JP7563912B2 - Resin materials and multilayer printed wiring boards - Google Patents

Description

The present invention relates to a resin material containing a compound having a cyclohexane ring. The present invention also relates to a multilayer printed wiring board using the above resin material.

Conventionally, various resin materials have been used to obtain electronic components such as semiconductor devices, laminates, and printed wiring boards. For example, in multilayer printed wiring boards, resin materials are used to form insulating layers for insulating between internal layers and to form insulating layers located on the surface. Wiring, which is generally metal, is laminated on the surface of the insulating layer. In addition, resin films in which the resin materials are filmized may be used to form the insulating layers. The resin materials and resin films are used as insulating materials for multilayer printed wiring boards, including build-up films.

The following Patent Document 1 discloses a resin composition containing a compound having a maleimide group, a divalent group having at least two imide bonds, and a saturated or unsaturated divalent hydrocarbon group. Patent Document 1 also describes that a cured product of this resin composition can be used as an insulating layer for a multilayer printed wiring board or the like.

The following Patent Document 2 discloses a resin composition for electronic materials that contains a bismaleimide compound having two maleimide groups and one or more polyimide groups having a specific structure. In the bismaleimide compound, the two maleimide groups are each independently bonded to both ends of the polyimide group via at least a first linking group in which eight or more atoms are linearly linked.

The following Patent Document 3 discloses a resin composition that contains (A) an epoxy compound and (B) a maleimide compound, in which the maleimide compound (B) contains either an alkyl group having 5 or more carbon atoms or an alkylene group having 5 or more carbon atoms.

WO2016/114286A1 JP 2018-90728 A JP 2019-44128 A

When an insulating layer is formed using conventional resin materials such as those described in Patent Documents 1 to 3, the dielectric tangent of the cured product may not be sufficiently low, or the thermal dimensional stability may not be sufficiently high.

In addition, with conventional resin materials, smears in the vias may not be sufficiently removed by the desmear process when forming the insulating layer.

Furthermore, when an insulating layer is formed using conventional resin materials, the surface roughness after etching may not be sufficiently small, and the plating peel strength with the metal layer laminated on the surface of the insulating layer by plating may not be sufficiently high.

The object of the present invention is to provide a resin material that can 1) reduce the dielectric tangent of the cured product, 2) increase the thermal dimensional stability of the cured product, 3) effectively remove smears by desmearing, 4) reduce the surface roughness after etching, and 5) increase the plating peel strength. Another object of the present invention is to provide a multilayer printed wiring board using the above resin material.

According to a broad aspect of the present invention, there is provided a resin material comprising at least one cyclohexane ring-containing compound selected from a maleimide compound having a cyclohexane ring and a benzoxazine compound having a cyclohexane ring, and a curing accelerator, the cyclohexane ring-containing compound having a first skeleton derived from an aliphatic diamine compound having a cyclohexane ring and a second skeleton derived from a dimer diamine, the aliphatic diamine compound having a cyclohexane ring is different from a dimer diamine, the average proportion of the first skeleton derived from the aliphatic diamine compound having a cyclohexane ring is 50 mol% or more and 85 mol% or less out of 100 mol% of all structural units of the skeleton derived from the diamine compound possessed by the cyclohexane ring-containing compound, and the average proportion of the second skeleton derived from the dimer diamine is 15 mol% or more and less than 50 mol% out of 100 mol% of all structural units of the skeleton derived from the diamine compound possessed by the cyclohexane ring-containing compound.

In a particular aspect of the resin material according to the present invention, the cyclohexane ring-containing compound has a third skeleton derived from a diamine compound different from the aliphatic diamine compound having a cyclohexane ring, and the diamine compound different from the aliphatic diamine compound having a cyclohexane ring is different from a dimer diamine.

In a particular aspect of the resin material according to the present invention, the third skeleton derived from a diamine compound other than the aliphatic diamine compound having a cyclohexane ring has an aromatic ring.

In a particular aspect of the resin material according to the present invention, the third skeleton derived from a diamine compound other than the aliphatic diamine compound having a cyclohexane ring has a fluorine atom.

In a specific aspect of the resin material according to the present invention, in the first skeleton derived from the aliphatic diamine compound having a cyclohexane ring, the nitrogen atom constituting the first amino group and the carbon atom constituting the cyclohexane ring are bonded directly or via two or less atoms.

In a specific aspect of the resin material according to the present invention, in the first skeleton derived from the aliphatic diamine compound having a cyclohexane ring, the nitrogen atom constituting the second amino group different from the first amino group is directly bonded to the carbon atom constituting the cyclohexane ring or is bonded via three or less atoms.

In a particular aspect of the resin material according to the present invention, the aliphatic diamine compound having a cyclohexane ring is tricyclodecane diamine, norbornane diamine, or isophorone diamine.

In a particular aspect of the resin material according to the present invention, the glass transition temperature of the cyclohexane ring-containing compound is 80°C or higher and 250°C or lower.

In a particular aspect of the resin material according to the present invention, the weight average molecular weight of the cyclohexane ring-containing compound is 2,000 or more and 100,000 or less.

In a particular aspect of the resin material according to the present invention, the resin material contains a thermosetting compound different from the cyclohexane ring-containing compound and a curing agent.

In a particular aspect of the resin material according to the present invention, the cyclohexane ring-containing compound is a maleimide compound having the cyclohexane ring, and the thermosetting compound includes a maleimide compound.

In a specific aspect of the resin material according to the present invention, the maleimide compound is a maleimide compound that does not have a skeleton derived from dimer diamine, or the maleimide compound is a maleimide compound that has a skeleton derived from dimer diamine and in which the average proportion of skeletons derived from dimer diamine is 50 mol % or more out of 100 mol % of all structural units of the skeleton derived from a diamine compound contained in the maleimide compound.

In a particular aspect of the resin material according to the present invention, the thermosetting compound includes an epoxy compound.

In a particular aspect of the resin material according to the present invention, the curing agent includes an active ester compound.

In a particular aspect of the resin material according to the present invention, the thermosetting compound includes a radically curable compound.

In a particular aspect of the resin material according to the present invention, the resin material contains an inorganic filler.

In a particular aspect of the resin material according to the present invention, the content of the inorganic filler is 50% by weight or more out of 100% by weight of the components excluding the solvent in the resin material.

In a particular aspect of the resin material according to the present invention, the inorganic filler is silica.

In a particular aspect of the resin material according to the present invention, the resin material is a resin film.

The resin material according to the present invention is suitable for use in forming insulating layers in multilayer printed wiring boards.

According to a broad aspect of the present invention, there is provided a multilayer printed wiring board comprising a circuit board, a plurality of insulating layers disposed on a surface of the circuit board, and a metal layer disposed between the plurality of insulating layers, at least one of the plurality of insulating layers being a cured product of the above-mentioned resin material.

The resin material according to the present invention includes at least one of a cyclohexane ring-containing compound, which is a maleimide compound having a cyclohexane ring and a benzoxazine compound having a cyclohexane ring, and a curing accelerator. In the resin material according to the present invention, the cyclohexane ring-containing compound has a first skeleton derived from an aliphatic diamine compound having a cyclohexane ring and a second skeleton derived from a dimer diamine, and the aliphatic diamine compound having a cyclohexane ring is different from a dimer diamine. In the resin material according to the present invention, the average proportion of the first skeleton derived from the aliphatic diamine compound having a cyclohexane ring is 50 mol% or more and 85 mol% or less out of the total structural units 100 mol% of the skeleton derived from the diamine compound possessed by the cyclohexane ring-containing compound. In the resin material according to the present invention, the average proportion of the second skeleton derived from the dimer diamine is 15 mol% or more and less than 50 mol% out of the total structural units 100 mol% of the skeleton derived from the diamine compound possessed by the cyclohexane ring-containing compound. The resin material according to the present invention has the above-mentioned features, which allow 1) the dielectric tangent of the cured product to be lowered, 2) the thermal dimensional stability of the cured product to be increased, 3) smears to be effectively removed by desmearing, 4) the surface roughness after etching to be reduced, and 5) the plating peel strength to be increased.

FIG. 1 is a cross-sectional view showing a multilayer printed wiring board using a resin material according to one embodiment of the present invention.

The present invention is described in detail below.

The resin material according to the present invention contains at least one cyclohexane ring-containing compound selected from the group consisting of a maleimide compound having a cyclohexane ring and a benzoxazine compound having a cyclohexane ring, and a curing accelerator.

In the resin material according to the present invention, the cyclohexane ring-containing compound has a first skeleton derived from an aliphatic diamine compound having a cyclohexane ring, and the aliphatic diamine compound having a cyclohexane ring is different from a dimer diamine.

In the resin material according to the present invention, the cyclohexane ring-containing compound has a second skeleton derived from dimer diamine.

In the resin material according to the present invention, the average proportion of the first skeleton derived from the aliphatic diamine compound having the cyclohexane ring is 50 mol % or more and 85 mol % or less out of 100 mol % of all structural units of the skeleton derived from the diamine compound possessed by the cyclohexane ring-containing compound.

In the resin material according to the present invention, the average proportion of the second skeleton derived from the dimer diamine is 15 mol % or more and less than 50 mol % of the total structural units of the skeleton derived from the diamine compound possessed by the cyclohexane ring-containing compound.

The resin material according to the present invention has the above-mentioned features, so 1) it is possible to lower the dielectric tangent of the cured product, 2) it is possible to increase the thermal dimensional stability of the cured product, 3) it is possible to effectively remove smears by desmearing, 4) it is possible to reduce the surface roughness after etching, and 5) it is possible to increase the plating peel strength. The resin material according to the present invention can achieve all of the effects 1)-5).

The resin material according to the present invention has the above-mentioned configuration, and therefore can enhance the compatibility between the cyclohexane ring-containing compound and a thermosetting compound different from the cyclohexane ring-containing compound. As a result, the occurrence of excessive phase separation can be suppressed, and the uniformity of the surface can be improved.

In addition, the resin material according to the present invention has the above-mentioned configuration, which can increase the flexibility of the B-stage film.

In addition, since the resin material according to the present invention has the above-mentioned configuration, the elongation characteristics of the cured product can be improved. Therefore, connection reliability can be improved even in areas where stress is likely to concentrate, such as multi-stage via stack sections.

The resin material according to the present invention may be a resin composition or a resin film. The resin composition has fluidity. The resin composition may be in a paste form. The paste form includes a liquid form. Since the resin material according to the present invention has excellent handleability, it is preferable that the resin material is a resin film.

The resin material according to the present invention is preferably a thermosetting material. When the resin material is a resin film, the resin film is preferably a thermosetting resin film.

Below, we will explain the details of each component used in the resin material according to the present invention, as well as the uses of the resin material according to the present invention. In addition, we will specifically explain preferred structures that can more effectively exert the effects of the present invention.

[Cyclohexane ring-containing compound]
The resin material according to the present invention includes a cyclohexane ring-containing compound. The cyclohexane ring-containing compound is at least one of a maleimide compound having a cyclohexane ring and a benzoxazine compound having a cyclohexane ring. In this specification, the "maleimide compound having a cyclohexane ring" may be described as a "maleimide compound containing a cyclohexane ring", and the "benzoxazine compound having a cyclohexane ring" may be described as a "benzoxazine compound containing a cyclohexane ring". Therefore, the cyclohexane ring-containing compound is at least one of a maleimide compound containing a cyclohexane ring and a benzoxazine compound containing a cyclohexane ring. The cyclohexane ring-containing compound may be used alone or in combination of two or more.

The cyclohexane ring-containing maleimide compound preferably has a maleimide skeleton at the terminal. The cyclohexane ring-containing maleimide compound may have a maleimide skeleton at a portion other than the terminal. The cyclohexane ring-containing maleimide compound may be used alone or in combination of two or more.

The cyclohexane ring-containing benzoxazine compound has a benzoxazine skeleton. The cyclohexane ring-containing benzoxazine compound may be used alone or in combination of two or more.

In this specification, a cyclohexane ring means a six-membered alicyclic structure in which six carbon atoms are bonded in a ring. The carbon atoms constituting the cyclohexane ring may be bonded to a hydrocarbon group having 1 to 20 carbon atoms, or may be bonded to a hydrocarbon group having 1 to 4 carbon atoms. The cyclohexane ring-containing compound may have a cyclohexane ring as a ring constituting a tricyclodecane ring, a norbornane ring, an adamantane skeleton, or the like. The cyclohexane ring-containing compound may have a structure in which multiple cyclohexane rings are connected via a hydrocarbon group such as an alkyl group.

Examples of the cyclohexane ring include rings represented by the following formulas (X1), (X2), (X3), (X4), and (X5):

In the above formula (X1), R1 to R10 each represent a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms. In the above formula (X1), R1 to R10 each preferably represent a hydrogen atom or a methyl group. In the above formula (X1), R1 to R10 may be the same or different.

In the above formula (X2), R1 to R10 each represent a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms. In the above formula (X2), R1 to R10 each preferably represent a hydrogen atom or a methyl group. In the above formula (X2), R1 to R10 may be the same or different.

In the above formula (X3), R1 to R18 each represent a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, and Q represents any group. In the above formula (X3), R1 to R18 each preferably represent a hydrogen atom or a methyl group. In the above formula (X3), Q is preferably a hydrocarbon group having 1 to 4 carbon atoms, or a group having an aromatic ring, more preferably an alkylene group, and even more preferably a methylene group. In the above formula (X3), when Q is a group having an aromatic ring, Q may be a group in which the aromatic rings are bonded to each other via an ester bond. In the above formula (X3), R1 to R18 may be the same or different.

In the above formula (X4), R1 to R8 each represent a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms. The ring represented in the above formula (X4) is a norbornane ring. In the above formula (X4), R1 to R8 each preferably represent a hydrogen atom or a methyl group. In the above formula (X4), R1 to R8 may be the same or different.

The cyclohexane ring may be a ring represented by the following formula (X4-1):

In the above formula (X4-1), R1 to R10 each represent a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, and two of R1 to R10 represent groups bonded to the nitrogen atom constituting the imide skeleton. In the above formula (X4-1), when R9 and R10 represent groups bonded to the nitrogen atom constituting the imide skeleton, it corresponds to the above formula (X4).

In the above formula (X5), R1 to R12 each represent a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms. The ring represented in the above formula (X5) is a tricyclodecane ring. In the above formula (X5), R1 to R12 each preferably represent a hydrogen atom or a methyl group. In the above formula (X5), R1 to R12 may be the same or different.

The cyclohexane ring may be a ring represented by the following formula (X5-1):

In the above formula (X5-1), R1 to R14 each represent a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, and two of R1 to R14 represent groups bonded to the nitrogen atom constituting the imide skeleton. In the above formula (X5-1), when R13 and R14 represent groups bonded to the nitrogen atom constituting the imide skeleton, this corresponds to the above formula (X5).

The cyclohexane ring-containing compound has a first skeleton derived from an aliphatic diamine compound having a cyclohexane ring, and the aliphatic diamine compound having the cyclohexane ring is different from a dimer diamine. Therefore, the aliphatic diamine compound is different from a dimer diamine and is an aliphatic diamine compound having a cyclohexane ring. The first skeleton has a cyclohexane ring.

In this specification, "an aliphatic diamine compound that is different from dimer diamine and has a cyclohexane ring" may be referred to as "aliphatic diamine compound A."

The cyclohexane ring-containing compound has a second skeleton derived from dimer diamine. Dimer diamine is a diamine compound. The second skeleton is different from the first skeleton.

The cyclohexane ring-containing compound may or may not have a third skeleton derived from a diamine compound different from the aliphatic diamine compound having a cyclohexane ring. However, with respect to the third skeleton, the aliphatic diamine compound having the cyclohexane ring (the diamine compound constituting the third skeleton) is different from dimer diamine. Therefore, the diamine compound constituting the third skeleton is a diamine compound that is different from dimer diamine and different from the aliphatic diamine compound having a cyclohexane ring (aliphatic diamine compound A). The third skeleton is different from the first skeleton. The third skeleton is different from the second skeleton. The third skeleton may or may not have a cyclohexane ring.

In this specification, a "diamine compound that is different from dimer diamine and different from an aliphatic diamine compound having a cyclohexane ring" may be referred to as "diamine compound B."

The skeleton and other details of the cyclohexane ring-containing compound will be described in more detail below. In addition, preferred structures that can more effectively exert the effects of the present invention will be specifically described below.

<First skeleton derived from aliphatic diamine compound A>
The cyclohexane ring-containing compound has a first skeleton derived from an aliphatic diamine compound A. The cyclohexane ring-containing compound has the cyclohexane ring by having at least the first skeleton derived from an aliphatic diamine compound A. The first skeleton derived from an aliphatic diamine compound A is present as a partial skeleton in the cyclohexane ring-containing compound.

Aliphatic diamine compound A is an aliphatic diamine compound different from dimer diamine. Aliphatic diamine compound A has a cyclohexane ring. Aliphatic diamine compound A has a first amino group and a second amino group.

It is preferable that the number of carbon atoms in the aliphatic diamine compound A is less than the number of carbon atoms in the dimer diamine (36). In other words, it is preferable that the number of carbon atoms in the aliphatic diamine compound A is less than 36.

The aliphatic diamine compound A may have one, two, or three or more cyclohexane rings.

The carbon atoms constituting the cyclohexane ring of the aliphatic diamine compound A may be bonded to a hydrocarbon group having 1 to 20 carbon atoms. The aliphatic diamine compound A may also have a cyclohexane ring as a ring constituting a tricyclodecane ring, a norbornane ring, an adamantane skeleton, or the like.

Examples of the cyclohexane ring contained in the aliphatic diamine compound A include rings represented by the above formula (X1), (X2), (X3), (X4), and (X5).

From the viewpoint of exerting the effects of the present invention more effectively, in the first skeleton derived from the aliphatic diamine compound A, it is preferable that the nitrogen atom constituting the first amino group and the carbon atom constituting the cyclohexane ring are directly bonded or bonded via two or less atoms. The atoms are preferably carbon atoms.

From the viewpoint of exerting the effects of the present invention more effectively, in the first skeleton derived from the aliphatic diamine compound A, it is preferable that the nitrogen atom constituting the second amino group and the carbon atom constituting the cyclohexane ring are directly bonded or bonded via three or less atoms. The atoms are preferably carbon atoms.

When the aliphatic diamine compound A has the tricyclodecane ring as the cyclohexane ring, in the first skeleton derived from the aliphatic diamine compound A, the nitrogen atom constituting the first amino group and the carbon atom constituting the tricyclodecane ring are preferably bonded directly or via two or less atoms. The atoms are preferably carbon atoms. In this case, the effects of the present invention can be exerted even more effectively.

When the aliphatic diamine compound A has the tricyclodecane ring as the cyclohexane ring, it is preferable that in the first skeleton derived from the aliphatic diamine compound A, the nitrogen atom constituting the second amino group and the carbon atom constituting the tricyclodecane ring are directly bonded or bonded via two or less atoms. In this case, the effect of the present invention can be exerted even more effectively. It is preferable that the atom is a carbon atom.

Examples of the first skeleton derived from the aliphatic diamine compound A include skeletons represented by the following formula (A1), (A2), (A3), (A4), (A5), and (A6).

In the above formula (A1), R1 to R10 each represent a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, and R11 and R12 each represent a group that constitutes a heterocycle together with the nitrogen atom. In the above formula (A1), it is preferable that R1 to R10 each represent a hydrogen atom or a methyl group. In the above formula (A1), R1 to R10 may be the same or different. In the above formula (A1), R11 and R12 may be the same or different.

In the skeleton represented by the above formula (A1), the nitrogen atom constituting the first amino group (amino group on the left) and the atom constituting the cyclohexane ring are bonded via one carbon atom, and the nitrogen atom constituting the second amino group (amino group on the right) and the atom constituting the cyclohexane ring are bonded via one carbon atom.

In the above formula (A2), R1 to R10 each represent a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, and R11 and R12 each represent a group that constitutes a heterocycle together with the nitrogen atom. In the above formula (A2), it is preferable that R1 to R10 each represent a hydrogen atom or a methyl group. In the above formula (A2), R1 to R10 may be the same or different. In the above formula (A2), R11 and R12 may be the same or different.

In the skeleton represented by the above formula (A2), the nitrogen atom constituting the first amino group (amino group on the left) is directly bonded to an atom constituting the cyclohexane ring, and the nitrogen atom constituting the second amino group (amino group on the right) is bonded to an atom constituting the cyclohexane ring via one carbon atom.

In the above formula (A3), R1 to R10 each represent a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, and R11 and R12 each represent a group that constitutes a heterocycle together with the nitrogen atom. In the above formula (A3), it is preferable that R1 to R10 each represent a hydrogen atom or a methyl group. In the above formula (A3), R1 to R10 may be the same or different. In the above formula (A3), R11 and R12 may be the same or different.

In the skeleton represented by the above formula (A3), the nitrogen atom constituting the first amino group (amino group on the left) and the atom constituting the cyclohexane ring are bonded via two carbon atoms, and the nitrogen atom constituting the second amino group (amino group on the right) and the atom constituting the cyclohexane ring are directly bonded.

In the above formula (A4), R1 to R18 each represent a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, R19 and R20 each represent a group that constitutes a heterocycle together with a nitrogen atom, and Q represents any group. In the above formula (A4), R1 to R18 each preferably represent a hydrogen atom or a methyl group. In the above formula (A4), Q is preferably a hydrocarbon group having 1 to 4 carbon atoms or a group having an aromatic ring, more preferably an alkylene group, and even more preferably a methylene group. In the above formula (A4), when Q is a group having an aromatic ring, Q may be a group in which the aromatic rings are bonded to each other via an ester bond. In the above formula (A4), R1 to R18 may be the same or different. In the above formula (A4), R19 and R20 may be the same or different.

In the skeleton represented by the above formula (A4), the nitrogen atom constituting the first amino group (amino group on the left) is directly bonded to an atom constituting the cyclohexane ring, and the nitrogen atom constituting the second amino group (amino group on the right) is directly bonded to an atom constituting the cyclohexane ring.

In the above formula (A5), R1 to R8 each represent a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, and R9 and R10 each represent a group that forms a heterocycle together with the nitrogen atom. In the above formula (A5), it is preferable that R1 to R8 each represent a hydrogen atom or a methyl group. In the above formula (A5), R1 to R8 may be the same or different. In the above formula (A5), R9 and R10 may be the same or different.

In the skeleton represented by the above formula (A5), the nitrogen atom constituting the first amino group (amino group on the left) and the atom constituting the cyclohexane ring are bonded via one carbon atom, and the nitrogen atom constituting the second amino group (amino group on the right) and the atom constituting the cyclohexane ring are bonded via one carbon atom.

The first skeleton derived from the aliphatic diamine compound A may be a skeleton represented by the following formula (A5-1).

In the above formula (A5-1), R1 to R8, R11, and R12 each represent a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, two of R1 to R8, R11, and R12 each represent a group bonded to the nitrogen atom constituting the imide skeleton, and R9 and R10 each represent a group constituting a heterocycle together with the nitrogen atom. In the above formula (A5-1), the case where R11 and R12 each represent a group bonded to the nitrogen atom constituting the imide skeleton corresponds to the above formula (A5). In the above formula (A5-1), it is preferable that R1 to R8, R11, and R12 each represent a hydrogen atom or a methyl group. In the above formula (A5-1), R1 to R8, R11, and R12 may be the same or different. In the above formula (A5-1), R9 and R10 may be the same or different.

In the above formula (A6), R1 to R12 each represent a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, and R13 and R14 each represent a group constituting a heterocycle together with a nitrogen atom. In the above formula (A6), it is preferable that R1 to R12 each represent a hydrogen atom or a methyl group. In the above formula (A6), R1 to R12 may be the same or different. In the above formula (A6), R13 and R14 may be the same or different.

In the skeleton represented by the above formula (A6), the nitrogen atom constituting the first amino group (amino group on the left) is bonded to the atom constituting the cyclohexane ring via one carbon atom, and the nitrogen atom constituting the second amino group (amino group on the right) is bonded to the atom constituting the cyclohexane ring via two carbon atoms. In the skeleton represented by the above formula (A6), the nitrogen atom constituting the second amino group is bonded to the carbon atom constituting the tricyclodecane ring via one carbon atom.

The first skeleton derived from the aliphatic diamine compound A may be a skeleton represented by the following formula (A6-1).

In the above formula (A6-1), R1 to R12, R15, and R16 each represent a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, two of R1 to R12, R15, and R16 each represent a group bonded to the nitrogen atom constituting the imide skeleton, and R13 and R14 each represent a group constituting a heterocycle together with the nitrogen atom. In the above formula (A6-1), the case where R15 and R16 each represent a group bonded to the nitrogen atom constituting the imide skeleton corresponds to the above formula (A6). In the above formula (A6-1), it is preferable that R1 to R12, R15, and R16 each represent a hydrogen atom or a methyl group. In the above formula (A6-1), R1 to R12, R15, and R16 may be the same or different. In the above formula (A6-1), R13 and R14 may be the same or different.

In the above formulas (A1), (A2), (A3), (A4), (A5), (A5-1), (A6) and (A6-1), examples of groups constituting a heterocycle together with the nitrogen atom include groups represented by the following formulas (A11), (A12) and (A13).

Hereinafter, further explanation will be given on compounds capable of forming the skeletons of the above formulae (A1), (A2), (A3), (A4), (A5) and (A6), and compounds capable of forming skeletons derived from aliphatic diamine compounds having a cyclohexane ring other than the skeletons of the above formulae (A1), (A2), (A3), (A4), (A5) and (A6).

Examples of the aliphatic diamine compound A include tricyclodecanediamine, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, bis(aminomethyl)norbornane, 3(4),8(9)-bis(aminomethyl)tricyclo[5.2.1.02,6]decane, 1,3-cyclohexanediamine, 1,4-cyclohexanediamine, isophoronediamine, 4,4'-methylenebis(cyclohexylamine), and 4,4'-methylenebis(2-methylcyclohexylamine). Only one type of aliphatic diamine compound A may be used, or two or more types may be used in combination.

From the viewpoint of exerting the effects of the present invention more effectively, the aliphatic diamine compound A is preferably tricyclodecane diamine, norbornane diamine, or isophorone diamine, and more preferably tricyclodecane diamine. When the aliphatic diamine compound A is tricyclodecane diamine, the cyclohexane ring-containing compound has, for example, the skeleton represented by the above formula (A6). When the aliphatic diamine compound A is norbornane diamine (bis(aminomethyl)norbornane), the cyclohexane ring-containing compound has, for example, the skeleton represented by the above formula (A5). When the aliphatic diamine compound A is isophorone diamine, the cyclohexane ring-containing compound has, for example, the skeleton represented by the above formula (A2).

The first skeleton derived from the aliphatic diamine compound A is preferably a skeleton derived from a reaction product of the aliphatic diamine compound A and an acid dianhydride. The skeleton derived from the reaction product of the aliphatic diamine compound A and an acid dianhydride has a first skeleton derived from the aliphatic diamine compound A.

Examples of the acid dianhydride include tetracarboxylic acid dianhydrides.

Examples of the tetracarboxylic dianhydride include pyromellitic dianhydride, 3,3',4,4'-benzophenone tetracarboxylic dianhydride, 3,3',4,4'-biphenylsulfone tetracarboxylic dianhydride, 1,4,5,8-naphthalene tetracarboxylic dianhydride, 2,3,6,7-naphthalene tetracarboxylic dianhydride, 3,3',4,4'-biphenyl ether tetracarboxylic dianhydride, 3,3',4,4'-dimethyldiphenylsilane tetracarboxylic dianhydride, 3,3',4,4'-tetraphenylsilane tetracarboxylic dianhydride, 1,2,3,4-furan tetracarboxylic dianhydride, 4,4'-bis(3,4-dicarboxyphenoxy)diphenyl sulfide dianhydride, 4,4'-bis(3,4-dicarboxyphenoxy)diphenyl sulfone dianhydride, 4,4'-bis(3,4-dicarboxylic acid ... xyphenoxy)diphenylpropane dianhydride, 3,3',4,4'-perfluoroisopropylidenediphthalic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, bis(phthalic acid)phenylphosphine oxide dianhydride, p-phenylene-bis(triphenylphthalic acid) dianhydride, m-phenylene-bis(triphenylphthalic acid) dianhydride, bis(triphenylphthalic acid)-4,4'-diphenylether dianhydride, bis(triphenylphthalic acid)-4,4'-diphenylmethane dianhydride, 4,4'-(hexafluoroisopropylidene)diphthalic anhydride, bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, and 5-(2,5-dioxotetrahydrofuryl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride.

From the viewpoint of further increasing the thermal dimensional stability of the cured product and increasing compatibility with other resins, the average proportion of the first skeleton derived from the aliphatic diamine compound A is 50 mol % or more and 85 mol % or less out of 100 mol % of all structural units of the skeleton derived from the diamine compound possessed by the cyclohexane ring-containing compound.

In the total structural units 100 mol% of the skeleton derived from the diamine compound possessed by the cyclohexane ring-containing compound, the average ratio of the first skeleton derived from the aliphatic diamine compound A is preferably 60 mol% or more, more preferably 65 mol% or more, even more preferably 70 mol% or more, preferably 80 mol% or less, and more preferably 75 mol% or less. When the average ratio of the first skeleton derived from the aliphatic diamine compound A is equal to or greater than the lower limit, the effect of the present invention can be more effectively exhibited. In addition, when the average ratio of the first skeleton derived from the aliphatic diamine compound A is equal to or greater than the lower limit, the glass transition temperature of the resin material can be further increased. When the average ratio of the first skeleton derived from the aliphatic diamine compound A is equal to or less than the upper limit, the compatibility of the cyclohexane ring-containing compound with a thermosetting compound different from the cyclohexane ring-containing compound can be further increased, and the surface uniformity after lamination and pre-curing can be further increased. In addition, since the concentration of the imide skeleton can be increased, the desmear property can be improved.

<Second skeleton derived from dimer diamine>
The cyclohexane ring-containing compound has a second skeleton derived from dimer diamine. The cyclohexane ring-containing compound has the cyclohexane ring by having the second skeleton derived from dimer diamine. The second skeleton derived from dimer diamine exists as a partial skeleton in the cyclohexane ring-containing compound. However, since dimer diamine is, for example, a mixture (natural product), it may be difficult to define the structure of the dimer diamine as a single structure. Therefore, the dimer diamine may contain, for example, a dimer diamine having a cyclohexene ring.

The cyclohexane ring-containing compound has a second skeleton derived from dimer diamine, so that the dielectric tangent of the cured product can be reduced, and smears can be effectively removed by desmearing. The second skeleton derived from the dimer diamine is a flexible skeleton. Therefore, when the cyclohexane ring-containing compound has a second skeleton derived from the dimer diamine, the sheet properties of resin films such as B-stage films can be improved. In addition, the elongation properties and stress relaxation properties of the cured product can be improved, so that warping can be effectively suppressed and the reliability of multilayer printed wiring boards and the like can be improved. In addition, the embeddability during lamination can be improved.

The second skeleton derived from the dimer diamine is preferably a skeleton derived from a reaction product of the dimer diamine and an acid dianhydride. The skeleton derived from the reaction product of the dimer diamine and an acid dianhydride has the second skeleton derived from the dimer diamine.

Examples of the dimer diamine include VERSAMINE 551 (product name, manufactured by BASF Japan, 3,4-bis(1-aminoheptyl)-6-hexyl-5-(1-octenyl)cyclohexene), VERSAMINE 552 (product name, manufactured by Cognix Japan, hydrogenated VERSAMINE 551), and PRIAMINE 1075 and PRIAMINE 1074 (product names, both manufactured by Croda Japan).

The above-mentioned acid dianhydrides include the above-mentioned tetracarboxylic acid dianhydrides.

From the viewpoints of lowering the dielectric tangent of the cured product, reducing the surface roughness after etching, and increasing the plating peel strength, the average proportion of the second skeleton derived from the dimer diamine is 15 mol % or more and less than 50 mol % out of 100 mol % of all structural units of the skeleton derived from the diamine compound possessed by the cyclohexane ring-containing compound.

In the total structural units (100 mol%) of the skeleton derived from the diamine compound contained in the cyclohexane ring-containing compound, the average proportion of the second skeleton derived from the dimer diamine is preferably 18 mol% or more, more preferably 20 mol% or more, preferably 40 mol% or less, more preferably 30 mol% or less. When the average proportion of the second skeleton derived from the dimer diamine is equal to or less than the upper limit, the effect of the present invention can be more effectively exhibited. When the average proportion of the second skeleton derived from the dimer diamine is equal to or less than the lower limit, the smear can be more effectively removed by the desmear treatment, and the flexibility of the resin film (B-stage film) and the elongation properties of the cured product can be further improved. In addition, the embedding property into the uneven surface during lamination can be improved.

<Third skeleton derived from diamine compound B>
The cyclohexane ring-containing compound does not have a third skeleton derived from diamine compound B or has a third skeleton derived from diamine compound B. When the cyclohexane ring-containing compound has a third skeleton derived from diamine compound B, the third skeleton derived from diamine compound B is present as a partial skeleton in the cyclohexane ring-containing compound.

Diamine compound B is a diamine compound different from both aliphatic diamine compound A and dimer diamine. Diamine compound B may or may not have an aromatic ring. Diamine compound B may or may not have an aromatic ring. Diamine compound B may or may not have an aliphatic ring. Diamine compound B may or may not have an aliphatic ring.

The diamine compound B may or may not have a fluorine atom. In addition, the diamine compound B may or may not have a phenolic hydroxyl group. When the diamine compound B is an aromatic diamine compound having a phenolic hydroxyl group, the linear expansion coefficient can be further reduced.

The diamine compound B may be an aliphatic diamine compound that does not have a cyclohexane skeleton, a diamine compound that has a cyclohexane skeleton and does not have an aliphatic skeleton, or a diamine compound that does not have a cyclohexane skeleton and does not have an aliphatic skeleton. The diamine compound B may be an aliphatic diamine compound that does not have a cyclohexane skeleton, a diamine compound that has a cyclohexane skeleton and does not have an aliphatic skeleton, or a diamine compound that does not have a cyclohexane skeleton and does not have an aliphatic skeleton. When the diamine compound B is a diamine compound that has an aromatic ring, the diamine compound B may or may not have a carbon chain between the aromatic ring and the amino group.

The aromatic rings include a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, a tetracene ring, a chrysene ring, a triphenylene ring, a tetraphene ring, a pyrene ring, a pentacene ring, a picene ring, and a perylene ring.

Examples of the aliphatic ring include a monocycloalkane ring, a bicycloalkane ring, a tricycloalkane ring, a tetracycloalkane ring, and a dicyclopentadiene ring.

From the viewpoint of further increasing the thermal dimensional stability of the cured product, it is preferable that the cyclohexane ring-containing compound has a third skeleton derived from diamine compound B having an aromatic ring. From the viewpoint of further increasing the thermal dimensional stability of the cured product, it is preferable that the third skeleton derived from diamine compound B has an aromatic ring.

The third skeleton derived from the diamine compound B is preferably a skeleton derived from a reaction product of the diamine compound B and an acid dianhydride. The skeleton derived from the reaction product of the diamine compound B and an acid dianhydride has a third skeleton derived from the diamine compound B. From the viewpoint of reducing the dielectric tangent and dielectric constant of the cured product, it is preferable that the third skeleton derived from the diamine compound B has a fluorine atom.

Examples of diamine compound B include 1,1-bis(4-aminophenyl)cyclohexane, 2,7-diaminofluorene, 4,4'-ethylenedianiline, 4,4'-methylenebis(2,6-diethylaniline), 4,4'-methylenebis(2-ethyl-6-methylaniline), 1,4-diaminobutane, 1,10-diaminodecane, 1,12-diaminododecane, 1,7-diaminoheptane, 1,6-diaminohexane, 1,5-diaminopentane, 1,8-diaminooctane, 1,3-diaminopropane, 1,11-diaminoundecane, 2-methyl-1,5-diaminopentane, 4,4'-isopropylidenebis(2-aminophenol), 4,4'-(hexafluoroisopropylidene)bis(2-aminophenol), and 4,4'-(hexafluoroisopropylidene)dianiline. Diamine compound B may be used alone or in combination of two or more.

The above-mentioned acid dianhydrides include the above-mentioned tetracarboxylic acid dianhydrides.

In order to improve the thermal dimensional stability of the cured product, the average proportion of the third skeleton derived from diamine compound B is less than 35 mol % out of 100 mol % of all structural units of the skeleton derived from the diamine compound possessed by the cyclohexane ring-containing compound.

In the total structural units 100 mol% of the skeleton derived from the diamine compound possessed by the cyclohexane ring-containing compound, the average proportion of the third skeleton derived from the diamine compound B is preferably 0 mol% or more, more preferably 5 mol% or more, preferably 20 mol% or less, more preferably 10 mol% or less. When the average proportion of the third skeleton derived from the diamine compound B is equal to or greater than the above lower limit and equal to or less than the above upper limit, the effect of the present invention can be more effectively exhibited. In the total structural units 100 mol% of the skeleton derived from the diamine compound possessed by the cyclohexane ring-containing compound, the average proportion of the third skeleton derived from the diamine compound B may be 0 mol% or may exceed 0 mol%. In particular, when a diamine compound having an aromatic skeleton is used as the diamine compound B, it is preferable to satisfy the above preferred range from the viewpoint of solubility. In addition, when a diamine compound having a hetero element other than the amine portion is used as the diamine compound B, when the average proportion of the third skeleton derived from the diamine compound B is equal to or greater than the above lower limit and equal to or less than the above upper limit, the adhesion to copper can be further improved.

The average proportion of the first skeleton derived from the aliphatic diamine compound A, the average proportion of the second skeleton derived from the dimer diamine compound, and the average proportion of the third skeleton derived from the diamine compound B in 100 mol % of all structural units derived from the diamine compound contained in the cyclohexane ring-containing compound can be calculated, for example, from the peak area of ¹ H-NMR.

The cyclohexane ring-containing compound may or may not have a branched structure.

The weight average molecular weight of the cyclohexane ring-containing compound is preferably 1000 or more, more preferably 2000 or more, even more preferably 3500 or more, particularly preferably 4000 or more, preferably 100000 or less, more preferably 70000 or less, even more preferably 25000 or less, even more preferably 18000 or less, and particularly preferably 15000 or less. When the weight average molecular weight is equal to or greater than the lower limit, the linear expansion coefficient can be kept low. In addition, when the weight average molecular weight exceeds 25000, the melt viscosity of the resin material becomes higher than when the weight average molecular weight is 25000 or less, and the embeddability in the uneven surface may decrease.

The weight average molecular weight above indicates the weight average molecular weight in terms of polystyrene measured by gel permeation chromatography (GPC).

From the viewpoint of further increasing the thermal dimensional stability of the cured product and further increasing the adhesion between the insulating layer and the metal layer, the glass transition temperature of the cyclohexane ring-containing compound is preferably greater than 75°C, more preferably 80°C or higher, even more preferably 85°C or higher, particularly preferably 90°C or higher, and preferably 250°C or lower.

The glass transition temperature can be determined from the inflection point of the reverse heat flow by heating from -30°C to 260°C at a heating rate of 3°C/min in a nitrogen atmosphere using a differential scanning calorimeter (e.g., TA Instruments' "Q2000").

The content of the cyclohexane ring-containing compound in 100% by weight of the components in the resin material excluding the inorganic filler and the solvent is preferably 3% by weight or more, more preferably 5% by weight or more, even more preferably 10% by weight or more, particularly preferably 15% by weight or more, preferably 80% by weight or less, and more preferably 70% by weight or less. If the content of the cyclohexane ring-containing compound is equal to or more than the lower limit, the dielectric tangent of the cured product can be further lowered and the linear expansion coefficient can be further reduced. If the content of the cyclohexane ring-containing compound is equal to or less than the upper limit, the uniformity of the surface roughness after etching can be improved.

The cyclohexane ring-containing maleimide compound can be prepared, for example, as follows. The aliphatic diamine compound A is reacted with an acid dianhydride to obtain a first reactant. The obtained first reactant is reacted with dimer diamine to obtain a second reactant. The obtained second reactant is reacted with maleic anhydride.

The number of the maleimide skeletons in the cyclohexane ring-containing maleimide compound is preferably 2 or more, more preferably 3 or more, and preferably 10 or less, more preferably 5 or less. When the number of the maleimide skeletons is equal to or more than the above lower limit and equal to or less than the above upper limit, the effect of the present invention can be more effectively exerted.

The cyclohexane ring-containing maleimide compound preferably has an imide skeleton. The number of imide skeletons in the cyclohexane ring-containing maleimide compound is preferably 1 or more, more preferably 2 or more, and preferably 15 or less, more preferably 10 or less.

The cyclohexane ring-containing compound may have an even number of imide skeletons, an odd number of imide skeletons, or a mixture of a compound having an even number of imide skeletons and a compound having an odd number of imide skeletons.

The cyclohexane ring-containing benzoxazine compound can be prepared, for example, as follows. An aliphatic diamine compound A is reacted with an acid dianhydride to obtain a first reactant having amino groups at both ends. The obtained first reactant is reacted with paraform and phenol.

[Thermosetting compound]
The resin material preferably contains a thermosetting compound different from the cyclohexane ring-containing compound. The thermosetting compound may have a skeleton derived from a dimer diamine. The thermosetting compound preferably contains a thermosetting compound different from a maleimide compound having a skeleton derived from an aliphatic diamine compound having a cyclohexane ring. The thermosetting compound may be used alone or in combination of two or more.

The above-mentioned thermosetting compounds include maleimide compounds, epoxy compounds, cyanate compounds, vinyl compounds, phenoxy compounds, oxetane compounds, polyarylate compounds, diallyl phthalate compounds, episulfide compounds, (meth)acrylic compounds, amino compounds, unsaturated polyester compounds, polyurethane compounds, and silicone compounds.

The thermosetting compound is preferably a maleimide compound, an epoxy compound, or a vinyl compound, more preferably contains an epoxy compound or a vinyl compound, and even more preferably contains an epoxy compound. The vinyl compound preferably contains a styrene compound or an acrylate compound, and more preferably contains a styrene compound. In this case, the dielectric tangent of the cured product can be further lowered and the thermal dimensional stability of the cured product can be further improved.

<Maleimide Compound>
The maleimide compound is a maleimide compound (hereinafter, sometimes referred to as "maleimide compound X") different from the cyclohexane ring-containing maleimide compound. Only one type of the maleimide compound X may be used, or two or more types may be used in combination.

The maleimide compound X may be a bismaleimide compound.

Examples of the maleimide compound X include N-phenylmaleimide and N-alkylbismaleimide.

The maleimide compound X may or may not have a skeleton derived from dimer diamine.

When the cyclohexane ring-containing compound is the cyclohexane ring-containing maleimide compound, the resin material preferably contains the maleimide compound X. In this case, the maleimide compound X is preferably a maleimide compound that satisfies the following (1) or (2): (1) A maleimide compound that does not have a skeleton derived from dimer diamine. (2) A maleimide compound that has a skeleton derived from dimer diamine, and in which the average proportion of skeletons derived from dimer diamine is 50 mol % or more out of 100 mol % of all structural units of the skeleton derived from a diamine compound contained in the maleimide compound.

The maleimide compound X preferably has an aromatic ring.

In the maleimide compound X, it is preferable that the nitrogen atom in the maleimide skeleton is bonded to an aromatic ring.

From the viewpoint of further enhancing the thermal dimensional stability of the cured product, the content of the maleimide compound X is preferably 0.5% by weight or more, more preferably 1% by weight or more, and preferably 15% by weight or less, more preferably 10% by weight or less, based on 100% by weight of the components excluding the solvent in the resin material.

The content of the maleimide compound X in 100% by weight of the components in the resin material excluding the inorganic filler and the solvent is preferably 2% by weight or more, more preferably 5% by weight or more, preferably 50% by weight or less, more preferably 35% by weight or less, and even more preferably 20% by weight or less. When the content of the maleimide compound X is equal to or more than the lower limit and equal to or less than the upper limit, the thermal dimensional stability of the cured product can be further improved.

From the viewpoint of effectively exerting the effects of the present invention, the molecular weight of the maleimide compound X is preferably 500 or more, more preferably 1000 or more, and preferably less than 30000, more preferably less than 20000.

When the maleimide compound X is not a polymer and when the structural formula of the maleimide compound X can be specified, the molecular weight of the maleimide compound X means the molecular weight that can be calculated from the structural formula. When the maleimide compound X is a polymer, the molecular weight of the maleimide compound X means the weight average molecular weight in terms of polystyrene measured by gel permeation chromatography (GPC).

Commercially available products of the maleimide compound X include, for example, "BMI-4000" and "BMI-5100" manufactured by Daiwa Kasei Kogyo Co., Ltd., "MIR-3000" manufactured by Nippon Kayaku Co., Ltd., and "BMI-3000" and "BMI-689" manufactured by Designer Molecules Inc.

<Epoxy Compound>
As the epoxy compound, a conventionally known epoxy compound can be used. The epoxy compound is an organic compound having at least one epoxy group. The epoxy compound may be used alone or in combination of two or more kinds.

The above epoxy compounds include bisphenol A type epoxy compounds, bisphenol F type epoxy compounds, bisphenol S type epoxy compounds, phenol novolac type epoxy compounds, biphenyl type epoxy compounds, biphenyl novolac type epoxy compounds, biphenol type epoxy compounds, naphthalene type epoxy compounds, fluorene type epoxy compounds, phenol aralkyl type epoxy compounds, naphthol aralkyl type epoxy compounds, dicyclopentadiene type epoxy compounds, anthracene type epoxy compounds, epoxy compounds having an adamantane skeleton, epoxy compounds having a tricyclodecane skeleton, naphthylene ether type epoxy compounds, and epoxy compounds having a triazine nucleus in the skeleton.

The epoxy compound may be a glycidyl ether compound. The glycidyl ether compound is a compound having at least one glycidyl ether group.

From the viewpoint of further reducing the dielectric tangent of the cured product, it is preferable that the above epoxy compound contains an epoxy compound having a fluorine atom.

From the viewpoint of further lowering the dielectric tangent of the cured product and increasing the thermal dimensional stability and flame retardancy of the cured product, the above epoxy compound preferably contains an epoxy compound having an aromatic skeleton, preferably contains an epoxy compound having a naphthalene skeleton or a phenyl skeleton, and more preferably is an epoxy compound having an aromatic skeleton.

From the viewpoint of further lowering the dielectric tangent of the cured product and improving the coefficient of linear expansion (CTE) of the cured product, it is preferable that the above epoxy compound contains an epoxy compound that is liquid at 25°C and an epoxy compound that is solid at 25°C.

The viscosity of the epoxy compound that is liquid at 25°C is preferably 1000 mPa·s or less, and more preferably 500 mPa·s or less, at 25°C.

The viscosity of the epoxy compound can be measured, for example, using a dynamic viscoelasticity measuring device ("VAR-100" manufactured by Rheologica Instruments).

It is more preferable that the molecular weight of the epoxy compound is 1000 or less. In this case, even if the content of the inorganic filler is 50% by weight or more out of 100% by weight of the components excluding the solvent in the resin material, a resin material with high fluidity can be obtained when forming the insulating layer. Therefore, when the uncured or B-staged resin material is laminated onto a circuit board, the inorganic filler can be uniformly present.

When the epoxy compound is not a polymer and when the structural formula of the epoxy compound can be specified, the molecular weight of the epoxy compound refers to the molecular weight that can be calculated from the structural formula. When the epoxy compound is a polymer, the molecular weight refers to the weight average molecular weight.

From the viewpoint of further improving the thermal dimensional stability of the cured product, the content of the above epoxy compound is preferably 4% by weight or more, more preferably 7% by weight or more, and preferably 15% by weight or less, more preferably 12% by weight or less, based on 100% by weight of the components excluding the solvent in the resin material.

The content of the epoxy compound is preferably 15% by weight or more, more preferably 25% by weight or more, preferably 50% by weight or less, more preferably 40% by weight or less, based on 100% by weight of the components in the resin material excluding the inorganic filler and the solvent. When the content of the epoxy compound is equal to or more than the lower limit and equal to or less than the upper limit, the thermal dimensional stability of the cured product can be further improved.

The weight ratio of the content of the epoxy compound to the total content of the cyclohexane ring-containing compound and the curing agent described later (content of the epoxy compound/total content of the cyclohexane ring-containing compound and the curing agent described later) is preferably 0.2 or more, more preferably 0.3 or more, and preferably 1 or less, more preferably 0.8 or less. When the weight ratio is equal to or more than the lower limit and equal to or less than the upper limit, the dielectric tangent can be further reduced and the thermal dimensional stability can be further improved.

<Vinyl Compounds>
As the vinyl compound, a conventionally known vinyl compound can be used. The vinyl compound is an organic compound having at least one vinyl group. The vinyl compound may be used alone or in combination of two or more kinds.

The vinyl compound may be a styrene compound, an acrylate compound, a divinyl compound, or the like. The divinyl compound may be a divinyl benzyl ether compound. The vinyl compound may be a divinyl compound having an aliphatic skeleton, or a divinyl ether compound.

The styrene compound may be a phenylene ether compound modified with a terminal styrene. The styrene compound may be used alone or in combination of two or more.

Commercially available styrene compounds include, for example, "OPE-2St" manufactured by Mitsubishi Gas Chemical Company, Inc.

The styrene compound and the vinyl compound such as the acrylate compound also correspond to radical curing compounds. Therefore, the thermosetting compound preferably includes a radical curing compound. The thermosetting compound preferably includes a radical curing compound other than a maleimide compound. The resin material preferably includes a radical curing compound.

The content of the vinyl compound in 100% by weight of the components in the resin material excluding the inorganic filler and the solvent is preferably 5% by weight or more, more preferably 10% by weight or more, even more preferably 20% by weight or more, preferably 80% by weight or less, and more preferably 70% by weight or less. When the content of the vinyl compound is equal to or more than the lower limit and equal to or less than the upper limit, the dielectric tangent of the cured product can be further lowered and the thermal dimensional stability can be further improved.

[Inorganic filler]
The resin material preferably contains an inorganic filler. By using the inorganic filler, the dielectric loss tangent of the cured product can be further reduced. In addition, by using the inorganic filler, the dimensional change of the cured product due to heat can be further reduced. The inorganic filler may be used alone or in combination of two or more kinds.

The inorganic fillers include silica, talc, clay, mica, hydrotalcite, alumina, magnesium oxide, aluminum hydroxide, diamond, aluminum nitride, and boron nitride.

The inorganic filler is preferably an inorganic filler with a thermal conductivity of 10 W/mK or more, such as alumina or boron nitride. In this case, heat dissipation can be improved.

From the viewpoint of reducing the surface roughness of the cured product, further increasing the adhesive strength between the cured product and the metal layer, forming finer wiring on the surface of the cured product, and imparting better insulation reliability to the cured product, the inorganic filler is preferably silica or alumina, more preferably silica, and even more preferably fused silica. The silica may be hollow silica. By using silica, the thermal expansion coefficient of the cured product is further reduced, and the dielectric tangent of the cured product is further reduced. In addition, by using silica, the surface roughness of the cured product is effectively reduced, and the adhesive strength between the cured product and the metal layer is effectively increased. The silica is preferably spherical in shape.

From the viewpoint of promoting resin curing regardless of the curing environment, effectively increasing the glass transition temperature of the cured product, and effectively reducing the coefficient of linear thermal expansion of the cured product, it is preferable that the inorganic filler be spherical silica.

From the viewpoint of increasing thermal conductivity and insulating properties, it is preferable that the inorganic filler is alumina or boron nitride. In particular, boron nitride has anisotropy, which can further reduce the coefficient of linear thermal expansion.

The average particle size of the inorganic filler is preferably 50 nm or more, more preferably 100 nm or more, even more preferably 500 nm or more, and preferably 5 μm or less, more preferably 3 μm or less, and even more preferably 1 μm or less. When the average particle size of the inorganic filler is equal to or greater than the lower limit and equal to or less than the upper limit, the surface roughness after etching can be reduced and the plating peel strength can be increased, and the adhesion between the insulating layer and the metal layer can be further improved.

The median diameter (d50) at 50% is used as the average particle diameter of the inorganic filler. The average particle diameter can be measured using a particle size distribution measuring device that uses a laser diffraction scattering method. Note that when the inorganic filler is an agglomerated particle, the average particle diameter of the inorganic filler means the primary particle diameter.

The inorganic filler is preferably spherical, and more preferably spherical silica. In this case, the surface roughness of the cured product is effectively reduced, and the adhesive strength between the cured product and the metal layer is effectively increased. When the inorganic filler is spherical, the aspect ratio of the inorganic filler is preferably 2 or less, and more preferably 1.5 or less.

The inorganic filler is preferably surface-treated, more preferably surface-treated with a coupling agent, and even more preferably surface-treated with a silane coupling agent. By surface-treating the inorganic filler, the surface roughness of the roughened cured product is further reduced, and the adhesive strength between the cured product and the metal layer is further increased. In addition, by surface-treating the inorganic filler, finer wiring can be formed on the surface of the cured product, and better inter-wiring insulation reliability and inter-layer insulation reliability can be imparted to the cured product.

Examples of the coupling agent include silane coupling agents, titanium coupling agents, and aluminum coupling agents. Examples of the silane coupling agent include methacrylsilane, acrylic silane, amino silane, imidazole silane, vinyl silane, and epoxy silane.

The content of the inorganic filler is preferably 50% by weight or more, more preferably 60% by weight or more, even more preferably 65% by weight or more, particularly preferably 68% by weight or more, preferably 90% by weight or less, more preferably 85% by weight or less, even more preferably 80% by weight or less, and particularly preferably 75% by weight or less, based on 100% by weight of the resin material excluding the solvent. When the content of the inorganic filler is equal to or more than the lower limit, the dielectric tangent is effectively lowered. When the content of the inorganic filler is equal to or less than the upper limit, the thermal dimensional stability is improved and the warping of the cured product can be effectively suppressed. When the content of the inorganic filler is equal to or more than the lower limit and equal to or less than the upper limit, the surface roughness of the cured product can be further reduced, and finer wiring can be formed on the surface of the cured product. Furthermore, with this content of the inorganic filler, it is possible to lower the thermal expansion coefficient of the cured product and at the same time improve the smear removal properties.

[Curing agent]
The resin material preferably contains a curing agent. The curing agent is not particularly limited. A conventionally known curing agent can be used as the curing agent. The curing agent may be used alone or in combination of two or more kinds.

The above curing agents include phenol compounds (phenol curing agents), active ester compounds, cyanate ester compounds (cyanate ester curing agents), benzoxazine compounds without a cyclohexane ring (benzoxazine curing agents), carbodiimide compounds (carbodiimide curing agents), amine compounds (amine curing agents), thiol compounds (thiol curing agents), phosphine compounds, dicyandiamide, and acid anhydrides. The above curing agents preferably have functional groups that can react with the epoxy groups of the above epoxy compounds.

From the viewpoint of further lowering the dielectric tangent of the cured product and further increasing the thermal dimensional stability of the cured product, it is preferable that the curing agent contains at least one component selected from the group consisting of phenolic compounds, active ester compounds, cyanate ester compounds, benzoxazine compounds having no cyclohexane rings, carbodiimide compounds, and acid anhydrides. From the viewpoint of further lowering the dielectric tangent of the cured product and further increasing the thermal dimensional stability of the curing agent, it is more preferable that the curing agent contains at least one component selected from the group consisting of phenolic compounds, active ester compounds, cyanate ester compounds, benzoxazine compounds having no cyclohexane rings, and carbodiimide compounds, and it is even more preferable that the curing agent contains an active ester compound.

From the viewpoint of further improving thermal dimensional stability, it is preferable that the thermosetting compound contains an epoxy compound and the curing agent contains both a phenol compound and an active ester compound.

Examples of the phenolic compounds include novolac-type phenols, biphenol-type phenols, naphthalene-type phenols, dicyclopentadiene-type phenols, aralkyl-type phenols, and dicyclopentadiene-type phenols.

Commercially available products of the above phenol compounds include novolac type phenols (DIC Corporation's "TD-2091"), biphenyl novolac type phenols (Meiwa Chemical Industry Co., Ltd.'s "MEH-7851"), aralkyl type phenol compounds (Meiwa Chemical Industry Co., Ltd.'s "MEH-7800"), and phenols having an aminotriazine skeleton (DIC Corporation's "LA-1356" and "LA-3018-50P").

The above-mentioned active ester compound refers to a compound that contains at least one ester bond in the structure and has an aliphatic chain, an aliphatic ring, or an aromatic ring bonded to both sides of the ester bond. The active ester compound is obtained, for example, by a condensation reaction between a carboxylic acid compound or a thiocarboxylic acid compound and a hydroxy compound or a thiol compound. An example of an active ester compound is a compound represented by the following formula (1).

In the above formula (1), X1 represents a group containing an aliphatic chain, a group containing an aliphatic ring, or a group containing an aromatic ring, and X2 represents a group containing an aromatic ring. Preferred examples of the group containing an aromatic ring include a benzene ring which may have a substituent, and a naphthalene ring which may have a substituent. Examples of the substituent include a hydrocarbon group. The number of carbon atoms in the hydrocarbon group is preferably 12 or less, more preferably 6 or less, and even more preferably 4 or less.

In the above formula (1), examples of the combination of X1 and X2 include a combination of a benzene ring which may have a substituent and a benzene ring which may have a substituent, and a combination of a benzene ring which may have a substituent and a naphthalene ring which may have a substituent. Furthermore, in the above formula (1), examples of the combination of X1 and X2 include a combination of a naphthalene ring which may have a substituent and a naphthalene ring which may have a substituent.

The active ester compound is not particularly limited. From the viewpoint of further improving the thermal dimensional stability and flame retardancy, the active ester compound is preferably an active ester compound having two or more aromatic skeletons. From the viewpoint of lowering the dielectric tangent of the cured product and improving the thermal dimensional stability of the cured product, it is more preferable that the active ester compound has a naphthalene ring or a dicyclopentadiene skeleton in the main chain skeleton.

Commercially available products of the above active ester compounds include "HPC-8000-65T", "EXB9416-70BK", "EXB8100-65T", "HPC-8150-62T" and "EXB-8" manufactured by DIC Corporation.

From the viewpoint of lowering the melt viscosity of the resin material, shortening the distance between crosslinking points, and further reducing the linear expansion coefficient of the cured product, it is preferable that the active ester compound is an ester compound having low molecular weight activity. Commercially available ester compounds having low molecular weight activity include the above-mentioned "EXB-8" manufactured by DIC Corporation.

The above cyanate ester compounds include novolac-type cyanate ester resins, bisphenol-type cyanate ester resins, and prepolymers in which these are partially trimerized. The above novolac-type cyanate ester resins include phenol novolac-type cyanate ester resins and alkylphenol-type cyanate ester resins. The above bisphenol-type cyanate ester resins include bisphenol A-type cyanate ester resins, bisphenol E-type cyanate ester resins, and tetramethylbisphenol F-type cyanate ester resins.

Commercially available products of the above cyanate ester compounds include phenol novolac type cyanate ester resins (PT-30 and PT-60 manufactured by Lonza Japan) and prepolymers in which bisphenol type cyanate ester resins are trimerized (BA-230S, BA-3000S, BTP-1000S, and BTP-6020S manufactured by Lonza Japan).

The content of the cyanate ester compound in 100% by weight of the components in the resin material excluding the inorganic filler and the solvent is preferably 10% by weight or more, more preferably 15% by weight or more, even more preferably 20% by weight or more, preferably 85% by weight or less, and more preferably 75% by weight or less. When the content of the cyanate ester compound is equal to or more than the lower limit and equal to or less than the upper limit, the thermal dimensional stability of the cured product can be further improved.

Examples of the benzoxazine compounds that do not have a cyclohexane ring include P-d type benzoxazine and F-a type benzoxazine.

Commercially available benzoxazine compounds that do not have a cyclohexane ring include "P-d type" manufactured by Shikoku Chemical Industry Co., Ltd. and "ODA-BOZ" manufactured by JFE Chemical Corporation.

The content of the benzoxazine compound not having a cyclohexane ring in the resin material (100% by weight, excluding inorganic fillers and solvents) is preferably 1% by weight or more, more preferably 5% by weight or more, even more preferably 10% by weight or more, preferably 70% by weight or less, and more preferably 60% by weight or less. When the content of the benzoxazine compound not having a cyclohexane ring is equal to or more than the lower limit and equal to or less than the upper limit, the dielectric tangent of the cured product can be lowered and the thermal dimensional stability of the cured product can be further improved.

The carbodiimide compound is a compound having a structural unit represented by the following formula (2). In the following formula (2), the right end and the left end are bonding sites with other groups. The above carbodiimide compounds may be used alone or in combination of two or more types.

In the above formula (2), X represents an alkylene group, a group in which a substituent is bonded to an alkylene group, a cycloalkylene group, a group in which a substituent is bonded to a cycloalkylene group, an arylene group, or a group in which a substituent is bonded to an arylene group, and p represents an integer of 1 to 5. When there are multiple Xs, the multiple Xs may be the same or different.

In one preferred embodiment, at least one X is an alkylene group, a group in which a substituent is bonded to an alkylene group, a cycloalkylene group, or a group in which a substituent is bonded to a cycloalkylene group.

Commercially available products of the above carbodiimide compounds include "Carbodilite V-02B", "Carbodilite V-03", "Carbodilite V-04K", "Carbodilite V-07", "Carbodilite V-09", "Carbodilite 10M-SP", and "Carbodilite 10M-SP (modified)" manufactured by Nisshinbo Chemical Co., Ltd., as well as "Stavaxol P", "Stavaxol P400", and "Hi-Kasil 510" manufactured by Rhein Chemie.

Examples of the acid anhydrides include tetrahydrophthalic anhydride and alkylstyrene-maleic anhydride copolymers.

Commercially available products of the above acid anhydrides include "Rikacid TDA-100" manufactured by New Japan Chemical Co., Ltd.

The content of the curing agent relative to 100 parts by weight of the epoxy compound is preferably 70 parts by weight or more, more preferably 85 parts by weight or more, preferably 150 parts by weight or less, more preferably 120 parts by weight or less. When the content of the curing agent is equal to or more than the lower limit and equal to or less than the upper limit, the curing property is more excellent, the thermal dimensional stability is further improved, and the volatilization of the remaining unreacted components can be further suppressed.

The total content of the cyclohexane ring-containing compound, the thermosetting compound, and the curing agent in the resin material (100% by weight, excluding inorganic fillers and solvents) is preferably 50% by weight or more, more preferably 60% by weight or more, and preferably 98% by weight or less, more preferably 95% by weight or less. When the total content is equal to or more than the lower limit and equal to or less than the upper limit, the curability is even better and the thermal dimensional stability can be further improved.

[Curing accelerator]
The resin material includes a curing accelerator. The use of the curing accelerator further accelerates the curing speed. By quickly curing the resin material, the crosslinked structure in the cured product becomes uniform, and the number of unreacted functional groups is reduced, resulting in a high crosslink density. The curing accelerator is not particularly limited, and a conventionally known curing accelerator can be used. The curing accelerator may be used alone or in combination of two or more.

Examples of the curing accelerator include anionic curing accelerators such as imidazole compounds, cationic curing accelerators such as amine compounds, curing accelerators other than anionic and cationic curing accelerators such as phosphorus compounds and organometallic compounds, and radical curing accelerators such as peroxides.

The above imidazole compounds include 2-undecylimidazole, 2-heptadecylimidazole, 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 1,2-dimethylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, and 1-cyanoethyl-2-phenylimidazolium trimethylate. Examples include melitate, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-undecylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-ethyl-4'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine isocyanuric acid adduct, 2-phenylimidazole isocyanuric acid adduct, 2-methylimidazole isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole, and 2-phenyl-4-methyl-5-dihydroxymethylimidazole.

Examples of the amine compounds include diethylamine, triethylamine, diethylenetetramine, triethylenetetramine, and 4,4-dimethylaminopyridine.

Examples of the phosphorus compounds include triphenylphosphine compounds.

The organometallic compounds include zinc naphthenate, cobalt naphthenate, tin octoate, cobalt octoate, cobalt bisacetylacetonate (II), and cobalt trisacetylacetonate (III).

Examples of the above peroxides include dicumyl peroxide and perhexyl 25B.

From the viewpoint of further reducing the curing temperature and effectively suppressing warping of the cured product, it is preferable that the curing accelerator contains the anionic curing accelerator, and it is more preferable that the curing accelerator contains the imidazole compound.

From the viewpoint of further reducing the curing temperature and effectively suppressing warping of the cured product, the content of the anionic curing accelerator in 100% by weight of the curing accelerator is preferably 20% by weight or more, more preferably 50% by weight or more, even more preferably 70% by weight or more, and most preferably 100% by weight (total amount). Therefore, it is most preferable that the curing accelerator is the anionic curing accelerator.

When the thermosetting compound contains a radically curable compound such as the vinyl compound, the acrylate compound, and the styrene compound, radical curing proceeds, so the curing accelerator preferably contains the radical curing accelerator, and more preferably contains a radical curing accelerator having a one-minute half-life temperature of 170°C or higher and 200°C or lower. Commercially available radical curing accelerators having a one-minute half-life temperature of 170°C or higher and 200°C or lower include "Perhexine 25B" manufactured by NOF Corporation.

The content of the curing accelerator is not particularly limited. The content of the curing accelerator is preferably 0.01% by weight or more, more preferably 0.05% by weight or more, preferably 5% by weight or less, more preferably 3% by weight or less, based on 100% by weight of the components in the resin material excluding the inorganic filler and the solvent. When the content of the curing accelerator is equal to or more than the lower limit and equal to or less than the upper limit, the resin material is cured efficiently. When the content of the curing accelerator is within a more preferred range, the storage stability of the resin material is further improved, and a better cured product is obtained.

[Thermoplastic resin]
The resin material preferably contains a thermoplastic resin. Examples of the thermoplastic resin include polyvinyl acetal resin, polyimide resin, phenoxy resin, and styrene-butadiene resin. The thermoplastic resin may be used alone or in combination of two or more kinds.

From the viewpoint of effectively lowering the dielectric tangent and effectively increasing the adhesion of the metal wiring regardless of the curing environment, the thermoplastic resin is preferably a phenoxy resin. The use of phenoxy resin prevents the resin film from becoming less able to fill holes or irregularities in the circuit board and prevents the inorganic filler from becoming non-uniform. In addition, the use of phenoxy resin improves the dispersibility of the inorganic filler because the melt viscosity can be adjusted, and the resin composition or B-stage product is less likely to wet and spread to unintended areas during the curing process.

The phenoxy resin contained in the resin material is not particularly limited. Any conventionally known phenoxy resin can be used as the phenoxy resin. Only one type of the phenoxy resin may be used, or two or more types may be used in combination.

Examples of the phenoxy resin include phenoxy resins having a skeleton such as a bisphenol A skeleton, a bisphenol F skeleton, a bisphenol S skeleton, a biphenyl skeleton, a novolac skeleton, a naphthalene skeleton, and an imide skeleton.

Commercially available products of the above phenoxy resins include, for example, "YP50", "YP55", and "YP70" manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., and "1256B40", "4250", "4256H40", "4275", "YX6954BH30", and "YX8100BH30" manufactured by Mitsubishi Chemical Corporation.

From the viewpoint of improving handling properties, plating peel strength at low roughness, and adhesion between the insulating layer and the metal layer, the thermoplastic resin is preferably a polyimide resin (polyimide compound).

From the viewpoint of improving solubility, the polyimide compound is preferably a polyimide compound obtained by reacting a tetracarboxylic dianhydride with a dimer diamine.

Examples of the tetracarboxylic dianhydride include pyromellitic dianhydride, 3,3',4,4'-benzophenone tetracarboxylic dianhydride, 3,3',4,4'-biphenylsulfone tetracarboxylic dianhydride, 1,4,5,8-naphthalene tetracarboxylic dianhydride, 2,3,6,7-naphthalene tetracarboxylic dianhydride, 3,3',4,4'-biphenyl ether tetracarboxylic dianhydride, 3,3',4,4'-dimethyldiphenylsilane tetracarboxylic dianhydride, 3,3',4,4'-tetraphenylsilane tetracarboxylic dianhydride, 1,2,3,4-furan tetracarboxylic dianhydride, 4,4'-bis(3,4-dicarboxyphenoxy)diphenylsulfonyl tetracarboxylic dianhydride, and 4,4'-bis(3,4-dicarboxyphenoxy)diphenylsulfonyl tetracarboxylic dianhydride. dianhydride, 4,4'-bis(3,4-dicarboxyphenoxy)diphenylsulfone dianhydride, 4,4'-bis(3,4-dicarboxyphenoxy)diphenylpropane dianhydride, 3,3',4,4'-perfluoroisopropylidenediphthalic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, bis(phthalic acid)phenylphosphine oxide dianhydride, p-phenylene-bis(triphenylphthalic acid) dianhydride, m-phenylene-bis(triphenylphthalic acid) dianhydride, bis(triphenylphthalic acid)-4,4'-diphenyl ether dianhydride, and bis(triphenylphthalic acid)-4,4'-diphenylmethane dianhydride are examples of such anhydrides.

Examples of the dimer diamine include VERSAMINE 551 (product name, manufactured by BASF Japan, 3,4-bis(1-aminoheptyl)-6-hexyl-5-(1-octenyl)cyclohexene), VERSAMINE 552 (product name, manufactured by Cognix Japan, hydrogenated VERSAMINE 551), PRIAMINE 1075, and PRIAMINE 1074 (product names, all manufactured by Croda Japan).

The polyimide compound may have an acid anhydride structure, a maleimide structure, or a citraconic imide structure at the end. In this case, the polyimide compound can be reacted with an epoxy compound. By reacting the polyimide compound with an epoxy compound, the thermal dimensional stability of the cured product can be improved.

From the viewpoint of obtaining a resin material with even better storage stability, the weight average molecular weight of the thermoplastic resin, the polyimide resin, and the phenoxy resin is preferably 10,000 or more, more preferably 15,000 or more, and preferably 100,000 or less, more preferably 50,000 or less.

The weight average molecular weights of the thermoplastic resin, polyimide resin, and phenoxy resin are polystyrene-equivalent weight average molecular weights measured by gel permeation chromatography (GPC).

The contents of the thermoplastic resin, the polyimide resin, and the phenoxy resin are not particularly limited. In 100% by weight of the components in the resin material excluding the inorganic filler and the solvent, the content of the thermoplastic resin (when the thermoplastic resin is a polyimide resin or a phenoxy resin, the content of the polyimide resin or the phenoxy resin) is preferably 1% by weight or more, more preferably 2% by weight or more, preferably 30% by weight or less, more preferably 20% by weight or less. When the content of the thermoplastic resin is equal to or more than the lower limit and equal to or less than the upper limit, the resin material has good embedding properties in holes or irregularities in the circuit board. When the content of the thermoplastic resin is equal to or more than the lower limit, the formation of the resin film becomes easier, and a better insulating layer is obtained. When the content of the thermoplastic resin is equal to or less than the upper limit, the thermal expansion coefficient of the cured product becomes even lower. When the content of the thermoplastic resin is equal to or less than the upper limit, the surface roughness of the surface of the cured product becomes even smaller, and the adhesive strength between the cured product and the metal layer becomes even higher.

[solvent]
The resin material does not contain or contains a solvent. By using the solvent, the viscosity of the resin material can be controlled within a suitable range, and the coatability of the resin material can be improved. The solvent may be used to obtain a slurry containing the inorganic filler. Only one type of the solvent may be used, or two or more types may be used in combination.

The above-mentioned solvents include acetone, methanol, ethanol, butanol, 2-propanol, 2-methoxyethanol, 2-ethoxyethanol, 1-methoxy-2-propanol, 2-acetoxy-1-methoxypropane, toluene, xylene, methyl ethyl ketone, N,N-dimethylformamide, methyl isobutyl ketone, N-methyl-pyrrolidone, n-hexane, cyclohexane, cyclohexanone, and naphtha, which is a mixture.

It is preferable that most of the solvent is removed when the resin composition is formed into a film. Therefore, the boiling point of the solvent is preferably 200°C or less, more preferably 180°C or less. The content of the solvent in the resin composition is not particularly limited. The content of the solvent can be changed as appropriate, taking into account the coatability of the resin composition, etc.

When the resin material is a B-stage film, the content of the solvent in 100% by weight of the B-stage film is preferably 1% by weight or more, more preferably 2% by weight or more, preferably 10% by weight or less, more preferably 5% by weight or less.

[Other ingredients]
For the purpose of improving impact resistance, heat resistance, resin compatibility, workability, and the like, the resin material may contain an organic filler, a leveling agent, a flame retardant, a coupling agent, a colorant, an antioxidant, an ultraviolet degradation inhibitor, a defoaming agent, a thickener, a thixotropy imparting agent, and the like.

The organic filler may be a particulate material made of benzoxazine resin, benzoxazole resin, fluororesin, acrylic resin, styrene resin, or the like. The fluororesin may be polytetrafluoroethylene (PTFE), or the like. By using fluororesin particles as the organic filler, the relative dielectric constant of the cured product can be further reduced. The average particle size of the organic filler is preferably 1 μm or less. If the average particle size of the organic filler is equal to or less than the upper limit, the surface roughness after etching can be reduced and the plating peel strength can be increased, and the adhesion between the insulating layer and the metal layer can be further improved. The average particle size of the organic filler may be 50 nm or more.

The median diameter (d50) at 50% is used as the average particle size of the organic filler. The average particle size can be measured using a laser diffraction scattering particle size distribution measuring device.

Examples of the coupling agent include silane coupling agents, titanium coupling agents, and aluminum coupling agents. Examples of the silane coupling agent include vinyl silane, amino silane, imidazole silane, and epoxy silane.

(Resin film)
The above-mentioned resin composition is molded into a film to obtain a resin film (B-stage product/B-stage film). The above-mentioned resin material is preferably a resin film. The resin film is preferably a B-stage film.

Methods for forming a resin composition into a film to obtain a resin film include the following: Extrusion molding, in which the resin composition is melt-kneaded and extruded using an extruder, and then molded into a film using a T-die or circular die. Casting molding, in which a resin composition containing a solvent is cast into a film. Other conventionally known film molding methods. Extrusion molding and casting molding are preferred because they can be made thinner. Films include sheets.

The resin composition is molded into a film and dried by heating for 1 to 10 minutes at, for example, 50°C to 150°C, to a degree that does not cause excessive curing due to heat, to obtain a resin film that is a B-stage film.

The film-like resin composition that can be obtained by the drying process described above is called a B-stage film. The B-stage film is in a semi-cured state. A semi-cured product is not completely cured, and curing can continue.

The resin film does not have to be a prepreg. If the resin film is not a prepreg, migration will not occur along the glass cloth or the like. In addition, when the resin film is laminated or precured, irregularities caused by the glass cloth will not occur on the surface.

The resin film can be used in the form of a laminated film comprising a metal foil or a base film and a resin film laminated on the surface of the metal foil or the base film. The metal foil is preferably a copper foil.

Examples of the base film of the laminated film include polyester resin films such as polyethylene terephthalate film and polybutylene terephthalate film, olefin resin films such as polyethylene film and polypropylene film, and polyimide resin films. The surface of the base film may be subjected to a release treatment, if necessary.

From the viewpoint of controlling the degree of cure of the resin film more uniformly, the thickness of the resin film is preferably 5 μm or more and preferably 200 μm or less. When the resin film is used as an insulating layer of a circuit, the thickness of the insulating layer formed by the resin film is preferably equal to or greater than the thickness of the conductor layer (metal layer) that forms the circuit. The thickness of the insulating layer is preferably 5 μm or more and preferably 200 μm or less.

(Semiconductor device, printed wiring board, copper-clad laminate, and multilayer printed wiring board)
The above-mentioned resin material is suitably used for forming a molding resin in which a semiconductor chip is embedded in a semiconductor device.

The above resin material is preferably used as an insulating material. The above resin material is preferably used to form an insulating layer in a printed wiring board.

The printed wiring board is obtained, for example, by heating and pressurizing the resin material.

A laminated member having a metal layer on one or both sides can be laminated onto the resin film. A laminated structure can be suitably obtained, which includes a laminated member having a metal layer on its surface and a resin film laminated on the surface of the metal layer, the resin film being the resin material described above. There is no particular limitation on the method for laminating the resin film and the laminated member having the metal layer on its surface, and any known method can be used. For example, the resin film can be laminated onto the laminated member having a metal layer on its surface while applying pressure with or without heating using a device such as a parallel plate press or a roll laminator.

The material of the metal layer is preferably copper.

The lamination target component having the above-mentioned metal layer on its surface may be a metal foil such as copper foil.

The above resin material is preferably used to obtain a copper-clad laminate. One example of the above copper-clad laminate is a copper-clad laminate having copper foil and a resin film laminated on one surface of the copper foil.

The thickness of the copper foil of the copper-clad laminate is not particularly limited. The thickness of the copper foil is preferably within the range of 1 μm to 50 μm. In addition, in order to increase the adhesive strength between the cured resin material and the copper foil, it is preferable that the copper foil has fine irregularities on its surface. The method of forming the irregularities is not particularly limited. Examples of the method of forming the irregularities include a method of forming the irregularities by treatment using a known chemical solution.

The above resin materials are suitable for use in producing multilayer substrates.

One example of the multilayer board is a multilayer board including a circuit board and an insulating layer laminated on the circuit board. The insulating layer of the multilayer board is formed from the resin material. The insulating layer of the multilayer board may also be formed from the resin film of the laminated film using a laminated film. The insulating layer is preferably laminated on the surface of the circuit board on which the circuits are provided. A portion of the insulating layer is preferably embedded between the circuits.

In the multilayer board, it is preferable that the surface of the insulating layer opposite the surface on which the circuit board is laminated is roughened.

The roughening method can be any conventionally known roughening method, and is not particularly limited. The surface of the insulating layer may be subjected to a swelling treatment before the roughening treatment.

It is also preferable that the multilayer substrate further comprises a copper plating layer laminated on the roughened surface of the insulating layer.

Another example of the multilayer board is a multilayer board comprising a circuit board, an insulating layer laminated on the surface of the circuit board, and copper foil laminated on the surface of the insulating layer opposite to the surface on which the circuit board is laminated. The insulating layer is preferably formed by using a copper-clad laminate comprising copper foil and a resin film laminated on one surface of the copper foil, and curing the resin film. Furthermore, the copper foil is preferably etched to form a copper circuit.

Another example of the multilayer board is a multilayer board including a circuit board and a plurality of insulating layers laminated on a surface of the circuit board. At least one of the plurality of insulating layers arranged on the circuit board is formed using the resin material. It is preferable that the multilayer board further includes a circuit laminated on at least one surface of the insulating layer formed using the resin film.

Among multilayer substrates, multilayer printed wiring boards require a low dielectric tangent and high insulation reliability from the insulating layer. Therefore, the resin material according to the present invention is suitable for use in forming an insulating layer in a multilayer printed wiring board.

The multilayer printed wiring board includes, for example, a circuit board, a plurality of insulating layers arranged on the surface of the circuit board, and a metal layer arranged between the plurality of insulating layers. At least one of the insulating layers is a cured product of the resin material.

Figure 1 is a cross-sectional view showing a multilayer printed wiring board using a resin material according to one embodiment of the present invention.

In the multilayer printed wiring board 11 shown in FIG. 1, a plurality of insulating layers 13-16 are laminated on the upper surface 12a of the circuit board 12. The insulating layers 13-16 are cured layers. A metal layer 17 is formed on a partial region of the upper surface 12a of the circuit board 12. Of the plurality of insulating layers 13-16, the insulating layers 13-15 other than the insulating layer 16 located on the outer surface opposite the circuit board 12 side have a metal layer 17 formed on a partial region of the upper surface. The metal layer 17 is a circuit. The metal layer 17 is disposed between the circuit board 12 and the insulating layer 13, and between each of the laminated insulating layers 13-16. The lower metal layer 17 and the upper metal layer 17 are connected to each other by at least one of via hole connection and through hole connection not shown.

In the multilayer printed wiring board 11, the insulating layers 13 to 16 are formed from the cured product of the resin material. In this embodiment, the surfaces of the insulating layers 13 to 16 are roughened, so that fine holes (not shown) are formed in the surfaces of the insulating layers 13 to 16. The metal layer 17 extends into the fine holes. In the multilayer printed wiring board 11, the width dimension (L) of the metal layer 17 and the width dimension (S) of the portion where the metal layer 17 is not formed can be reduced. In the multilayer printed wiring board 11, good insulation reliability is provided between the upper metal layer and the lower metal layer that are not connected by via hole connections and through hole connections (not shown).

(Roughening treatment and swelling treatment)
The resin material is preferably used to obtain a cured product to be subjected to roughening treatment or desmear treatment. The cured product also includes a pre-cured product that can be further cured.

In order to form fine irregularities on the surface of the cured product obtained by pre-curing the above resin material, the cured product is preferably subjected to a roughening treatment. Before the roughening treatment, the cured product is preferably subjected to a swelling treatment. After the pre-curing and before the roughening treatment, the cured product is preferably subjected to a swelling treatment, and is further preferably cured after the roughening treatment. However, the cured product does not necessarily have to be subjected to a swelling treatment.

The swelling treatment may be carried out, for example, by treating the cured product with an aqueous solution or an organic solvent dispersion of a compound whose main component is ethylene glycol. The swelling liquid used in the swelling treatment generally contains an alkali as a pH adjuster. The swelling liquid preferably contains sodium hydroxide. Specifically, for example, the swelling treatment is carried out by treating the cured product with a 40% by weight aqueous solution of ethylene glycol at a treatment temperature of 30°C to 85°C for 1 to 30 minutes. The temperature of the swelling treatment is preferably within the range of 50°C to 85°C. If the temperature of the swelling treatment is too low, the swelling treatment takes a long time, and the adhesive strength between the cured product and the metal layer tends to be reduced.

In the above roughening treatment, a chemical oxidizing agent such as a manganese compound, a chromium compound, or a persulfate compound is used. These chemical oxidizing agents are used as an aqueous solution or an organic solvent dispersion solution after water or an organic solvent is added. The roughening liquid used in the roughening treatment generally contains an alkali as a pH adjuster or the like. The roughening liquid preferably contains sodium hydroxide.

The manganese compounds include potassium permanganate and sodium permanganate. The chromium compounds include potassium dichromate and potassium chromate anhydride. The persulfate compounds include sodium persulfate, potassium persulfate, and ammonium persulfate.

The arithmetic mean roughness Ra of the surface of the cured product is preferably 10 nm or more, and preferably less than 300 nm, more preferably less than 200 nm, and even more preferably less than 150 nm. In this case, the adhesive strength between the cured product and the metal layer is increased, and finer wiring is formed on the surface of the insulating layer. Furthermore, conductor loss can be suppressed, and signal loss can be kept low. The arithmetic mean roughness Ra is measured in accordance with JIS B0601:1994.

(Desmearing)
Through holes may be formed in the cured product obtained by pre-curing the resin material. In the multilayer board, etc., vias or through holes are formed as the through holes. For example, vias can be formed by irradiating a laser such as a _CO2 laser. The diameter of the via is not particularly limited, but is about 60 μm to 80 μm. Due to the formation of the through holes, smears, which are resin residues derived from the resin components contained in the cured product, are often formed at the bottom of the via.

In order to remove the smears, the surface of the cured product is preferably subjected to a desmear treatment. The desmear treatment may also serve as a roughening treatment.

In the desmear treatment, a chemical oxidizing agent such as a manganese compound, a chromium compound, or a persulfate compound is used, as in the roughening treatment. These chemical oxidizing agents are used as an aqueous solution or an organic solvent dispersion solution after water or an organic solvent is added. The desmear treatment liquid used in the desmear treatment generally contains an alkali. The desmear treatment liquid preferably contains sodium hydroxide.

By using the above resin material, the surface roughness of the desmeared cured product is sufficiently small.

The present invention will be specifically described below by giving examples and comparative examples. The present invention is not limited to the following examples.

The following materials were prepared:

(Cyclohexane ring-containing compound)
Cyclohexane ring-containing maleimide compound 1:
According to the following Synthesis Example 1, a cyclohexane ring-containing maleimide compound 1 (molecular weight 4500) represented by the following formula (1A) was synthesized. However, the structure of the cyclohexane ring-containing maleimide compound 1 represented by the following formula (1A) is only one example, and the cyclohexane ring-containing maleimide compound 1 is, for example, a mixture of a compound represented by the following formula (1A) and a compound having an amine position different from that of the compound. In the obtained cyclohexane ring-containing maleimide compound 1, the average proportion of the first skeleton derived from the aliphatic diamine compound A was 72 mol%, and the average proportion of the second skeleton derived from the dimer diamine was 28 mol%, out of 100 mol% of all structural units of the skeleton derived from the diamine compound.

<Synthesis Example 1>
As the aliphatic diamine compound A, tricyclodecanediamine was used.

100g of toluene, 36g of N-methyl-2-pyrrolidone (NMP), and 6g of methanesulfonic acid were placed in a 500mL eggplant flask. Then, 6.6g (16mmol) of dimer diamine ("PRIAMINE 1075" manufactured by Croda Japan) and 12.5g (64mmol) of tricyclodecane diamine were added. Then, 17.7g (60mmol) of biphenyl dianhydride was added little by little. The eggplant flask was attached to a Dean-Stark apparatus and heated under reflux for 3.5 hours. In this way, a compound having amines at both ends and multiple imide skeletons was obtained. After removing the moisture discharged during condensation and returning to room temperature, 4.42g (45mmol) of maleic anhydride was added and stirred, and similarly heated and reacted. In this way, a compound having maleimide skeletons at both ends was obtained. The organic layer was washed with a mixed solvent of water and ethanol, and the mixed solvent was removed to obtain a toluene solution. Next, isopropanol was added to the toluene solution to reprecipitate the product. It was then dried in a vacuum oven to obtain cyclohexane ring-containing maleimide compound 1.

Cyclohexane ring-containing maleimide compound 2:
According to the following Synthesis Example 2, a cyclohexane ring-containing maleimide compound 2 (molecular weight 12000) represented by the following formula (2A) was synthesized. However, the structure of the cyclohexane ring-containing maleimide compound 2 represented by the following formula (2A) is only one example, and the cyclohexane ring-containing maleimide compound 2 is, for example, a mixture of a compound represented by the following formula (2A) and a compound having an amine position different from that of the compound. In the obtained cyclohexane ring-containing maleimide compound 2, the average proportion of the first skeleton derived from the aliphatic diamine compound A was 65 mol %, and the average proportion of the second skeleton derived from the dimer diamine was 35 mol %, out of 100 mol % of all structural units of the skeleton derived from the diamine compound.

<Synthesis Example 2>
As the aliphatic diamine compound A, tricyclodecanediamine was used.

105 g of toluene, 41 g of N-methyl-2-pyrrolidone (NMP), and 7 g of methanesulfonic acid were placed in a 500 mL eggplant flask. Then, 9.3 g (23 mmol) of dimer diamine ("PRIAMINE 1075" manufactured by Croda Japan) and 10.2 g (53 mmol) of tricyclodecane diamine were added. Then, 13.1 g (60 mmol) of pyromellitic dianhydride was added little by little. The eggplant flask was attached to a Dean-Stark apparatus and heated under reflux for 3.5 hours. In this way, a compound having amines at both ends and multiple imide skeletons was obtained. After removing the moisture discharged during condensation and returning to room temperature, 4.42 g (45 mmol) of maleic anhydride was added and stirred, and similarly heated and reacted. In this way, a compound having maleimide skeletons at both ends was obtained. The organic layer was washed with a mixed solvent of water and ethanol, and the mixed solvent was removed to obtain a toluene solution. Next, isopropanol was added to the toluene solution to reprecipitate the product. It was then dried in a vacuum oven to obtain cyclohexane ring-containing maleimide compound 2.

Cyclohexane ring-containing maleimide compound 3:
Cyclohexane ring-containing maleimide compound 3 (molecular weight 4,300) was synthesized according to the following Synthesis Example 3. In the obtained cyclohexane ring-containing maleimide compound 3, the average proportion of the first skeleton derived from aliphatic diamine compound A was 66 mol %, and the average proportion of the second skeleton derived from dimer diamine was 34 mol %, relative to 100 mol % of all structural units derived from the diamine compound.

<Synthesis Example 3>
In a 500 mL eggplant flask, 105 g of toluene, 41 g of N-methyl-2-pyrrolidone (NMP), and 7 g of methanesulfonic acid were placed. Then, 9.9 g (24.2 mmol) of dimer diamine ("PRIAMINE 1075" manufactured by Croda Japan) and 8.6 g (55.8 mmol) of norbornane diamine ("Pro-NBDA" manufactured by Mitsui Fine Chemicals) were added. Then, 15.9 g (54 mmol) of biphenyl dianhydride and 1.5 g (6 mmol) of bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride were mixed and then added little by little. The eggplant flask was attached to a Dean-Stark apparatus and heated under reflux for 3.5 hours. In this way, a compound having amines at both ends and having multiple imide skeletons was obtained. The water discharged during the condensation was removed, and the mixture was returned to room temperature, after which 4.42 g (45 mmol) of maleic anhydride was added, stirred, and similarly heated to react. In this way, a compound having a maleimide skeleton at both ends was obtained. The organic layer was washed with a mixed solvent of water and ethanol, and the mixed solvent was removed to obtain a toluene solution. Next, isopropanol was added to the toluene solution to reprecipitate the product. The mixture was then dried in a vacuum oven to obtain a cyclohexane ring-containing maleimide compound 3.

Cyclohexane ring-containing maleimide compound 4:
Cyclohexane ring-containing maleimide compound 4 (molecular weight 4400) was synthesized according to the following Synthesis Example 4. In the obtained cyclohexane ring-containing maleimide compound 4, the average proportion of the first skeleton derived from aliphatic diamine compound A was 63 mol %, the average proportion of the second skeleton derived from dimer diamine compound A was 29 mol %, and the average proportion of the third skeleton derived from diamine compound B was 8 mol %, relative to 100 mol % of all structural units derived from the diamine compound.

<Synthesis Example 4>
In a 500 mL eggplant flask, 90 g of toluene, 46 g of N-methyl-2-pyrrolidone (NMP), and 7 g of methanesulfonic acid were placed. Then, 9.0 g (22 mmol) of dimer diamine ("PRIAMINE 1075" manufactured by Croda Japan) and 7.4 g (52 mmol) of norbornane diamine ("Pro-NBDA" manufactured by Mitsui Fine Chemicals) were added. Then, 2.0 g (6 mmol) of 4,4'-(hexafluoroisopropylidene)dianiline were added. Then, 15.9 g (54 mmol) of biphenyl dianhydride and 1.5 g (6 mmol) of bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride were mixed and then added little by little. The eggplant flask was attached to a Dean-Stark apparatus and heated under reflux for 3.5 hours. In this way, a compound having amines at both ends and a plurality of imide skeletons was obtained. After removing the moisture discharged during condensation and returning to room temperature, 4.42 g (45 mmol) of maleic anhydride was added and stirred, and similarly heated to react. In this way, a compound having maleimide skeletons at both ends was obtained. The organic layer was washed with a mixed solvent of water and ethanol, and the mixed solvent was removed with an evaporator to obtain a toluene solution. Next, isopropanol was added to the toluene solution to reprecipitate the product. The product was then dried in a vacuum oven to obtain cyclohexane ring-containing maleimide compound 4.

The molecular weights of the cyclohexane ring-containing maleimide compounds synthesized in Synthesis Examples 1 to 4 were determined as follows.

GPC (Gel Permeation Chromatography) Measurement:
Using a high performance liquid chromatograph system manufactured by Shimadzu Corporation, measurements were performed at a column temperature of 40°C and a flow rate of 1.0 ml/min, with tetrahydrofuran (THF) as the developing medium. An "SPD-10A" was used as the detector, and two "KF-804L" columns (exclusion limit molecular weight 400,000) manufactured by Shodex Corporation were used in series. "TSK Standard Polystyrene" manufactured by Tosoh Corporation was used as the standard polystyrene, and a calibration curve was created using substances with weight average molecular weights Mw = 354,000, 189,000, 98,900, 37,200, 17,100, 9,830, 5,870, 2,500, 1,050, and 500, and the molecular weight was calculated.

The average ratio of each skeleton of the cyclohexane ring-containing maleimide compounds synthesized in Synthesis Examples 1 to 4 was calculated from the signal area ratio of the hydrogen atom bonded to the carbon atom bonded to the nitrogen atom constituting each diamine skeleton by ¹ H-NMR measurement.

(Thermosetting Compound)
Biphenyl type epoxy compound ("NC-3000" manufactured by Nippon Kayaku Co., Ltd.)
Naphthalene-type epoxy compound ("ESN-475V" manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.)
Resorcinol diglycidyl ether ("EX-201" manufactured by Nagase Chemtex Corporation)
Epoxy compound having a glycidylamine skeleton ("630" manufactured by Mitsubishi Chemical Corporation)
Epoxy compound having a polybutadiene skeleton ("PB3600" manufactured by Daicel Corporation)
Epoxy compound having an amide skeleton ("WHR-991S" manufactured by Nippon Kayaku Co., Ltd.)
Hyperbranched aliphatic epoxy compound (Nissan Chemical's "Foldi E101")
Maleimide compound 1 (N-alkyl bismaleimide compound, "BMI-1500" manufactured by Designer Molecules Inc.)
Maleimide compound 2 (N-alkyl bismaleimide compound, "BMI-1700" manufactured by Designer Molecules Inc.)
Maleimide compound 3 (manufactured by Daiwa Kasei Co., Ltd., "BMI-4100")
Maleimide compound 4 ("MIR-3000" manufactured by Nippon Kayaku Co., Ltd.)
Styrene compound ("OPE-2St-1200" manufactured by Mitsubishi Gas Chemical Company, Inc., a radical curing compound, a styrene compound having a phenylene ether skeleton)
Acrylate compound (Kyoeisha Chemical's "Light Acrylate DCP-A", a radical curing compound, abbreviated as "DCP-A" in the table)

(Inorganic filler)
Silica-containing slurry (75% silica by weight: Admatechs "SC4050-HOA", average particle size 1.0 μm, aminosilane treatment, cyclohexanone 25% by weight)

(Hardening agent)
Active ester compound 1-containing solution (DIC Corporation "EXB-9416-70BK", solid content 70% by weight)
Active ester compound 2-containing liquid (DIC Corporation "HPC-8150-62T", solid content 62% by weight)
Active ester compound 3-containing liquid (DIC Corporation "HPC-8000L-65T", solid content 65% by weight)
Active ester compound 4 ("EXB-8" manufactured by DIC Corporation, solid content 100% by weight)
Carbodiimide compound ("Carbodilite V-03" manufactured by Nisshinbo Chemical Co., Ltd., abbreviated as "V-03" in the table)
Phenol compound-containing liquid (DIC Corporation "LA-1356", solid content 60% by weight)

(Cure Accelerator)
Dimethylaminopyridine ("DMAP" manufactured by Wako Pure Chemical Industries, Ltd.)
2-Phenyl-4-methylimidazole ("2P4MZ" manufactured by Shikoku Chemical Industry Co., Ltd., anionic curing accelerator)
Dicumyl Peroxide

(Thermoplastic resin)
Styrene butadiene resin ("Tuftec H1043" manufactured by Asahi Kasei Corporation, abbreviated as "H1043" in the table)
Alicyclic thermoplastic resin ("Neoresin EP-140" manufactured by JXTG Corporation, abbreviated as "EP-140" in the table)
Polyimide compounds (polyimide resins):
A solution containing a polyimide compound (non-volatile content: 26.8% by weight), which is a reaction product of tetracarboxylic dianhydride and dimer diamine, was synthesized according to Synthesis Example 5 below.

<Synthesis Example 5>
In a reaction vessel equipped with a stirrer, a water divider, a thermometer and a nitrogen gas inlet tube, 300.0 g of tetracarboxylic dianhydride ("BisDA-1000" manufactured by SABIC Japan LLC) and 665.5 g of cyclohexanone were placed, and the solution in the reaction vessel was heated to 60 ° C. Then, 89.0 g of dimer diamine ("PRIAMINE 1075" manufactured by Croda Japan) and 54.7 g of 1,3-bisaminomethylcyclohexane (manufactured by Mitsubishi Gas Chemical Co., Ltd.) were dropped into the reaction vessel. Next, 121.0 g of methylcyclohexane and 423.5 g of ethylene glycol dimethyl ether were added to the reaction vessel, and the imidization reaction was carried out at 140 ° C. for 10 hours. In this way, a polyimide compound-containing solution (non-volatile content 26.8 wt%) was obtained. The molecular weight (weight average molecular weight) of the obtained polyimide compound was 20,000. The molar ratio of acid component/amine component was 1.04.

The molecular weight of the polyimide compound synthesized in Synthesis Example 5 was determined as follows.

GPC (Gel Permeation Chromatography) Measurement:
Using a high performance liquid chromatograph system manufactured by Shimadzu Corporation, measurements were performed at a column temperature of 40°C and a flow rate of 1.0 ml/min, with tetrahydrofuran (THF) as the developing medium. An "SPD-10A" was used as the detector, and two "KF-804L" columns (exclusion limit molecular weight 400,000) manufactured by Shodex Corporation were used in series. "TSK Standard Polystyrene" manufactured by Tosoh Corporation was used as the standard polystyrene, and a calibration curve was created using substances with weight average molecular weights Mw = 354,000, 189,000, 98,900, 37,200, 17,100, 9,830, 5,870, 2,500, 1,050, and 500, and the molecular weight was calculated.

(Examples 1 to 10 and Comparative Examples 1 to 3)
The components shown in Tables 1 to 3 below were mixed in the amounts (unit: parts by weight of solid content) shown in Tables 1 to 3 below, and stirred at room temperature until a homogeneous solution was obtained, to obtain a resin material.

Preparation of resin film:
The obtained resin material was applied to the release-treated surface of a release-treated PET film ("XG284" manufactured by Toray Industries, Inc., thickness 25 μm) using an applicator, and then dried for 2 minutes and 30 seconds in a gear oven at 100° C. to volatilize the solvent. In this way, a laminated film (a laminated film of a PET film and a resin film) was obtained in which a resin film (B-stage film) having a thickness of 40 μm was laminated on the PET film.

(evaluation)
(1) Dielectric loss tangent The obtained resin film was heated at 190° C. for 90 minutes to obtain a cured product. The obtained cured product was cut into a size of 2 mm in width and 80 mm in length, and 10 sheets were stacked together. The dielectric loss tangent was measured at room temperature (23° C.) and a frequency of 5.8 GHz by the cavity resonance method using a "Cavity Resonance Perturbation Method Dielectric Constant Measurement Device CP521" manufactured by Kanto Electronics Application Development Co., Ltd. and a "Network Analyzer N5224A PNA" manufactured by Keysight Technologies, Inc.

[Criteria for dielectric tangent]
○: Dielectric tangent is less than 2.8×10 ⁻³ ×: Dielectric tangent is 2.8×10 ⁻³ or more

(2) Thermal dimensional stability (average coefficient of linear expansion (CTE))
The resulting resin film (B-stage film) having a thickness of 40 μm was heated at 190° C. for 90 minutes, and the resulting cured product was cut into pieces measuring 3 mm×25 mm. The average linear expansion coefficient (ppm/°C) of the cut cured material from 25°C to 150°C was measured under the conditions of a tensile load of 33 mN and a heating rate of 5°C/min using a thermocouple (EXSTAR TMA/SS6100 manufactured by Epson Corporation). was calculated.

[Criteria for Average Linear Expansion Coefficient]
○○: Average linear expansion coefficient is 25 ppm/°C or less. ○: Average linear expansion coefficient is more than 25 ppm/°C and less than 29 ppm/°C. ×: Average linear expansion coefficient is more than 29 ppm/°C.

(3) Desmearing ability (ability to remove residues at the via bottom)
Lamination and semi-curing process:
The obtained resin film was vacuum laminated onto a CCL substrate ("E679FG" manufactured by Hitachi Chemical Co., Ltd.) and semi-cured by heating at 180° C. for 30 minutes. In this way, a laminate A in which a semi-cured resin film was laminated onto a CCL substrate was obtained.

Via formation:
A via (through hole) having a diameter of 60 μm at the top and a diameter of 40 μm at the bottom (bottom) was formed using a _CO2 laser (manufactured by Hitachi Via Mechanics Co., Ltd.) in the semi-cured resin film of the obtained laminate A. In this way, a laminate B was obtained in which the semi-cured resin film was laminated on the CCL substrate and the via (through hole) was formed in the semi-cured resin film.

Via bottom residue removal process:
(a) Swelling Treatment The obtained laminate B was placed in a swelling liquid (Swelling Dip Securigant P, manufactured by Atotech Japan) at 60° C. and shaken for 10 minutes. Thereafter, it was washed with pure water.

(b) Permanganate treatment (roughening treatment and desmear treatment)
The laminate B after the swelling treatment was placed in a roughening aqueous solution of potassium permanganate ("Concentrate Compact CP" manufactured by Atotech Japan) at 80° C. and was shaken for 30 minutes. Next, it was treated for 2 minutes using a cleaning solution ("Reduction Securigant P" manufactured by Atotech Japan) at 25° C., and then washed with pure water to obtain evaluation sample 1.

The bottom of the via of evaluation sample 1 was observed with a scanning electron microscope (SEM) and the maximum smear length from the wall surface of the via bottom was measured. The removability of the residue at the via bottom was evaluated according to the following criteria.

[Criteria for Removability of Residue at Via Bottom]
○○: The maximum smear length is less than 2 μm. ○: The maximum smear length is 2 μm or more and less than 4 μm. ×: The maximum smear length is 4 μm or more.

(4) Surface roughness after etching (surface roughness) and uniformity of surface roughness Lamination process and semi-curing treatment:
A double-sided copper-clad laminate (CCL substrate) (Hitachi Chemical Co., Ltd. "E679FG") was prepared. Both sides of the copper foil surface of this double-sided copper-clad laminate were immersed in MEC Co., Ltd.'s "Cz8101" to roughen the copper foil surface. On both sides of the roughened copper-clad laminate, the resin film (B stage film) side of the laminate film was laminated on the copper-clad laminate using Meiki Seisakusho Co., Ltd.'s "batch vacuum laminator MVLP-500-IIA" to obtain a laminated structure. The lamination conditions were reduced pressure for 30 seconds to make the air pressure 13 hPa or less, and then pressed at 100 ° C and a pressure of 0.4 MPa for 30 seconds. Then, the resin film was heated at 180 ° C for 30 minutes to semi-cure. In this way, a laminate in which a semi-cured resin film was laminated on a CCL substrate was obtained.

Roughening treatment:
(a) Swelling treatment:
The obtained laminate was placed in a swelling liquid (Swelling Dip Securigant P, manufactured by Atotech Japan) at 60° C. and shaken for 10 minutes, and then washed with pure water.

(b) Permanganate treatment (roughening treatment and desmear treatment):
The laminate after the swelling treatment was placed in a roughening aqueous solution of potassium permanganate ("Concentrate Compact CP" manufactured by Atotech Japan) at 80° C. and swung for 30 minutes. Next, the laminate was treated for 2 minutes using a cleaning solution ("Reduction Securigant P" manufactured by Atotech Japan) at 25° C., and then washed with pure water to obtain an evaluation sample.

Surface roughness measurement:
On the surface of the evaluation sample (roughened cured product), 10 areas of 94 μm × 123 μm were arbitrarily selected. For each of the 10 areas, the arithmetic mean roughness Ra was measured using a non-contact three-dimensional surface profiler (Veeco's "WYKO NT1100"). The following surface roughness was evaluated from the average value of the arithmetic mean roughness Ra measured at the 10 points, and the following surface roughness uniformity was evaluated from the absolute value of the difference between the maximum and minimum values of the arithmetic mean roughness Ra measured at the 10 points. The arithmetic mean roughness Ra was measured in accordance with JIS B0601:1994.

[Criteria for surface roughness after etching]
◯: The average value of the arithmetic mean roughness Ra is less than 50 nm. ○: The average value of the arithmetic mean roughness Ra is 50 nm or more and less than 80 nm. ×: The average value of the arithmetic mean roughness Ra is 80 nm or more.

[Criteria for judging uniformity of surface roughness after etching]
◯: The absolute value of the difference between the maximum and minimum values of the arithmetic mean roughness Ra is less than 10 nm. Δ: The absolute value of the difference between the maximum and minimum values of the arithmetic mean roughness Ra is 10 nm or more and less than 20 nm. ×: The absolute value of the difference between the maximum and minimum values of the arithmetic mean roughness Ra is 20 nm or more.

(5) Plating peel strength Lamination process and semi-curing treatment:
A 100 mm square double-sided copper-clad laminate (CCL substrate) (Hitachi Chemical Co., Ltd. "E679FG") was prepared. Both sides of the copper foil surface of this double-sided copper-clad laminate were immersed in MEC Co., Ltd.'s "Cz8101" to roughen the copper foil surface. Using Meiki Seisakusho Co., Ltd.'s "batch-type vacuum laminator MVLP-500-IIA", the resin film (B stage film) side of the laminate film was laminated on both sides of the roughened copper-clad laminate to obtain a laminated structure. The lamination conditions were reduced pressure for 30 seconds to make the air pressure 13 hPa or less, and then laminated at 100 ° C. and a pressure of 0.7 MPa for 30 seconds, and further pressed at a press pressure of 0.8 MPa and a press temperature of 100 ° C. for 60 seconds. Thereafter, with the PET film still attached, the resin film in the laminated structure was heated at 100° C. for 30 minutes, and then further heated at 180° C. for 30 minutes to semi-cure the resin film. The PET film was then peeled off to obtain a laminate in which the semi-cured resin film was laminated on the CCL substrate.

Roughening treatment:
(a) Swelling treatment:
The obtained laminate was placed in a swelling liquid (Swelling Dip Securigant P, manufactured by Atotech Japan) at 60° C. and shaken for 10 minutes, and then washed with pure water.

(b) Permanganate treatment (roughening treatment and desmear treatment):
The laminate after the swelling treatment was placed in a roughening aqueous solution of potassium permanganate ("Concentrate Compact CP" manufactured by Atotech Japan) at 80° C. and swung for 30 minutes. Next, the laminate was treated for 2 minutes using a cleaning solution ("Reduction Securigant P" manufactured by Atotech Japan) at 25° C., and then washed with pure water to perform a roughening treatment.

Electroless plating process:
The surface of the roughened cured product was treated with an alkaline cleaner at 60°C (Atotech Japan's "Cleaner Securigant 902") for 5 minutes and degreased. After cleaning, the cured product was treated with a pre-dip liquid at 25°C (Atotech Japan's "Pre-dip Neogant B") for 2 minutes. The cured product was then treated with an activator liquid at 40°C (Atotech Japan's "Activator Neogant 834") for 5 minutes to attach a palladium catalyst. Next, the cured product was treated with a reducing liquid at 30°C (Atotech Japan's "Reducer Neogant WA") for 5 minutes.

Then, the cured material was placed in a chemical copper solution (Atotech Japan's "Basic Printganth MSK-DK", "Copper Printganth MSK", "Stabilizer Printganth MSK", and "Reducer Cu") and electroless plating was performed until the plating thickness reached approximately 0.5 μm. After electroless plating, the material was annealed at 120°C for 30 minutes to remove any remaining hydrogen gas. All steps up to the electroless plating step were performed using 2 L of treatment solution on a beaker scale while the cured material was agitated.

Electrolytic plating process:
Next, electrolytic plating was performed on the electroless plated cured product until the plating thickness reached 25 μm. As electrolytic copper plating, a copper sulfate solution ("copper sulfate pentahydrate" manufactured by Wako Pure Chemical Industries, Ltd., "sulfuric acid" manufactured by Wako Pure Chemical Industries, Ltd., "basic leveler Cupracid HL" manufactured by Atotech Japan, and "corrector Cupracid GS" manufactured by Atotech Japan) was used, and electrolytic plating was performed by passing a current of 0.6 A/cm ² until the plating thickness reached about 25 μm. After the copper plating, the cured product was heated at 200° C. for 60 minutes to further cure the cured product. In this way, a cured product having a copper plating layer laminated on the upper surface was obtained.

Measurement of plating peel strength:
A total of six 10 mm-wide rectangular cuts were made at 5 mm intervals on the surface of the copper plating layer of the cured product having a copper plating layer laminated on the upper surface. The cured product having a copper plating layer laminated on the upper surface was set in a 90° peel tester (TE-3001 manufactured by Tester Sangyo Co., Ltd.), the end of the copper plating layer with the cut was picked up with a gripper, and the copper plating layer was peeled off by 20 mm to measure the peel strength (plating peel strength). The peel strength (plating peel strength) was measured for each of the six cut locations, and the average plating peel strength was calculated. The plating peel strength was judged according to the following criteria.

[Criteria for plating peel strength]
○○: The average value of the plating peel strength is 0.5 kgf/cm or more. ○: The average value of the plating peel strength is 0.45 kgf/cm or more and less than 0.5 kgf/cm. △: The average value of the plating peel strength is 0.35 kgf/cm or more and less than 0.45 kgf/cm. ×: The average value of the plating peel strength is less than 0.35 kgf/cm.

(6) Glass transition temperature Tg
The obtained resin film (B-stage film) having a thickness of 40 μm was heated at 190° C. for 90 minutes, and the obtained cured product was cut into a size of 5 mm×50 mm. Measurements were performed using a thermomechanical analyzer (SII Nanotechnology Inc.'s "DMS6100") under the following conditions: chuck distance 20 mm, amplitude 10 μm, initial tension amplitude value 400 mN, temperature increase rate of 5° C./min from 50° C. to 330° C., and frequency of 10 Hz. In the obtained measurement results, the peak temperature of the loss tangent was taken as the glass transition temperature Tg (° C.).

[Criteria for determining glass transition temperature Tg]
○○: Tg is 180° C. or higher. ○: Tg is 175° C. or higher but less than 180° C. ×: Tg is less than 175° C.

(7) Embeddability into uneven surface Only the copper foil of a 100 mm square copper-clad laminate (a laminate of a 400 μm thick glass epoxy substrate and a 25 μm thick copper foil) was etched to open dents (openings) with a diameter of 100 μm and a depth of 25 μm in a straight line across a 30 mm square area in the center of the substrate, with the distance between the centers of adjacent holes being 900 μm. In this way, an evaluation substrate with a total of 900 dents was prepared.

The resin film side of the obtained laminated film was placed on the evaluation substrate, and heated and pressed at a lamination pressure of 0.4 MPa for 20 seconds, a press pressure of 0.8 MPa for 20 seconds, and a lamination and press temperature of 90°C using a Meiki Seisakusho batch vacuum laminator MVLP-500-IIA. After cooling to room temperature, the PET film was peeled off. In this way, an evaluation sample was obtained in which a resin film was laminated on an evaluation substrate.

The obtained evaluation samples were observed using an optical microscope to observe voids in the depressions. The percentage of depressions in which voids were observed was evaluated to determine the embeddability of the sample against an uneven surface according to the following criteria.

[Criteria for embeddability on uneven surfaces]
○: The percentage of voids observed was 0%.
△: The percentage of the number of depressions in which voids were observed was more than 0% and less than 5%. ×: The percentage of the number of depressions in which voids were observed was 5% or more.

(8) Flexibility of B-stage Film The obtained resin film (B-stage film) was folded 180 degrees at different positions a total of 10 times. The number of times that the resin film developed cracks or breaks was observed.

[Criteria for judging B-stage film flexibility]
OO: Cracking or cracking occurred less than 3 times out of 10 times. ○: Cracking or cracking occurred 3 or more times but less than 6 times out of 10 times. ×: Cracking or cracking occurred 6 or more times out of 10 times.

(9) Elongation properties of the cured product The obtained resin film (B-stage film) having a thickness of 40 μm was heated at 130° C. for 60 minutes, and then heated at 190° C. for 90 minutes to obtain a cured product, which was then cut into a size of 10 mm×100 mm. Using a tensile tester (Shimadzu Corporation, “AGS-J 100N”), measurements were performed under conditions of a chuck distance of 60 mm and a pulling speed of 5 mm/min, and the maximum elongation was measured. The initial tension was 0.35 N. The measurement was repeated five times, and the average value of the breaking elongation (average breaking elongation) was calculated.

[Criteria for evaluation of elongation properties of cured product]
◯: Average breaking elongation is 1.8% or more. ○: Average breaking elongation is 1.5% or more and less than 1.8%. ×: Average breaking elongation is less than 1.5%.

The compositions and results are shown in Tables 1 to 3 below.

11: multilayer printed wiring board 12: circuit board 12a: upper surface 13-16: insulating layers 17: metal layer

Claims (20)

a cyclohexane ring-containing compound which is a maleimide compound having a cyclohexane ring;
a thermosetting compound different from the cyclohexane ring-containing compound;
and a curing accelerator;
the cyclohexane ring-containing compound has a first skeleton derived from an aliphatic diamine compound having a cyclohexane ring and a second skeleton derived from a dimer diamine, the aliphatic diamine compound having a cyclohexane ring is different from a dimer diamine,
an average ratio of a first skeleton derived from an aliphatic diamine compound having a cyclohexane ring is 50 mol % or more and 85 mol % or less in relation to 100 mol % of all structural units of a skeleton derived from a diamine compound contained in the cyclohexane ring-containing compound;
an average ratio of the second skeleton derived from the dimer diamine to the total structural units (100 mol %) of the skeleton derived from the diamine compound contained in the cyclohexane ring-containing compound is 15 mol % or more and less than 50 mol %;
The resin material , wherein the thermosetting compound includes an epoxy compound . The resin material according to claim 1, wherein the cyclohexane ring-containing compound has a third skeleton derived from a diamine compound different from the aliphatic diamine compound having a cyclohexane ring, and the diamine compound different from the aliphatic diamine compound having a cyclohexane ring is different from a dimer diamine. The resin material according to claim 2, wherein the third skeleton derived from a diamine compound different from the aliphatic diamine compound having a cyclohexane ring has an aromatic ring. The resin material according to claim 2 or 3, wherein the third skeleton derived from a diamine compound different from the aliphatic diamine compound having a cyclohexane ring has a fluorine atom. The resin material according to any one of claims 1 to 4, wherein in the first skeleton derived from the aliphatic diamine compound having a cyclohexane ring, the nitrogen atom constituting the first amino group and the carbon atom constituting the cyclohexane ring are bonded directly or via two or less atoms. The resin material according to claim 5, wherein in the first skeleton derived from the aliphatic diamine compound having a cyclohexane ring, a nitrogen atom constituting a second amino group different from the first amino group is directly bonded to a carbon atom constituting the cyclohexane ring or is bonded via three or less atoms. The resin material according to any one of claims 1 to 6, wherein the aliphatic diamine compound having a cyclohexane ring is tricyclodecane diamine, norbornane diamine, or isophorone diamine. The resin material according to any one of claims 1 to 7, wherein the glass transition temperature of the cyclohexane ring-containing compound is 80°C or higher and 250°C or lower. The resin material according to any one of claims 1 to 8, wherein the weight average molecular weight of the cyclohexane ring-containing compound is 2,000 or more and 100,000 or less. The resin material according to any one of claims 1 to 9, further comprising a curing agent. The resin material of claim 10 , wherein the hardener comprises an active ester compound. The resin material according to any one of claims 1 to 11 , wherein the thermosetting compound comprises a maleimide compound. The maleimide compound as the thermosetting compound is a maleimide compound that does not have a skeleton derived from dimer diamine, or
13. The resin material according to claim 12, wherein the maleimide compound which is the thermosetting compound has a skeleton derived from a dimer diamine, and an average proportion of the skeleton derived from a dimer diamine is 50 mol % or more of all structural units (100 mol % ) of the skeleton derived from a diamine compound contained in the maleimide compound which is the thermosetting compound. The resin material according to claim 1 , wherein the thermosetting compound comprises a radically curable compound. The resin material according to any one of claims 1 to 14 , further comprising an inorganic filler. The resin material according to claim 15 , wherein the content of the inorganic filler is 50% by weight or more based on 100% by weight of components excluding the solvent in the resin material. The resin material according to claim 15 or 16 , wherein the inorganic filler is silica. The resin material according to any one of claims 1 to 17 , which is a resin film. The resin material according to any one of claims 1 to 18 , which is used to form an insulating layer in a multilayer printed wiring board. A circuit board;
a plurality of insulating layers disposed on a surface of the circuit board;
a metal layer disposed between a plurality of the insulating layers;
A multilayer printed wiring board, wherein at least one of the insulating layers is a cured product of the resin material according to any one of claims 1 to 19 .

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