JP2011124077A - Insulating sheet, laminated structure, and manufacturing method of laminated structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an insulating sheet and a laminated structure high in handleability at a non-cured state, capable of obtaining a cured object with high heat resistance and capable of restraining a warp of a laminated object laminated on the cured object. <P>SOLUTION: The insulating sheet contains a polymer with a diphenylene sulfone group, a curing compound with an epoxy group or an oxetane group, a curing agent and a filler. The laminated structure 1 is provided with a substrate 2 having a first conductive layer 2b at least on one of its faces and either a through-hole or a concave part on one of the faces, insulating layers 3, 4 laminated on one or both faces of the substrate 2, and second conductive layers 5, 8 laminated on a face opposite to the face of the substrate 2 laminated with the insulating layers 3, 4 or a circuit board. The insulating layers 3, 4 are formed by curing the insulating sheet. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an insulating sheet that can be used, for example, to form an insulating layer of a laminated structure such as a multilayer substrate, a laminated structure using the insulating sheet, and a method for manufacturing the laminated structure.

  In recent years, printed wiring boards having an insulating layer have been used in electronic devices and communication devices. The insulating layer is formed using a paste-like or sheet-like insulating material.

  As an example of the printed wiring board, for example, in Patent Document 1 below, a resin layer, a circuit board on which wiring circuits are formed on both surfaces of the resin layer, and a surface on both sides of the circuit board are formed. A multilayer wiring board having an insulating layer is disclosed. A via hole is formed in the circuit board. A conductive film is formed on the inner peripheral surface of the via hole. Wiring circuits formed on the surfaces on both sides of the resin layer are connected by the conductive film. The via hole is filled with a first insulating material and cured to form an insulating portion. This first insulating material contains an electrically insulating filler having a high thermal conductivity and a resin having a low thermal expansion characteristic equal to or lower than that of the metal of the conductive film. In addition, after the insulating portion is formed, an insulating layer is formed by applying and curing a second insulating material on the wiring circuit of the circuit board.

  Patent Document 2 below discloses a multilayer wiring board including a circuit board having a concave portion on the upper surface and an insulating layer laminated on the upper surface of the circuit board. A first insulating layer is formed by filling a concave portion on the upper surface of the circuit board with a first insulating material so as to fill the concave portion and curing the first insulating material. This first insulating material contains an inorganic filler having a high thermal conductivity. In addition, after the first insulating layer is formed, the second insulating layer is formed by laminating and curing a sheet-like second insulating material on the circuit board.

Japanese Patent Laid-Open No. 10-163594 Japanese Patent Laid-Open No. 07-226583

  In recent years, the electronic devices and communication devices have been miniaturized and information processing speeded up. For this reason, in the printed multilayer wiring board used for the said electronic device, multilayering and thinning are progressing, and the mounting density of an electronic component is high. Along with this, a large amount of heat is easily generated from the electronic components, and the need to dissipate the generated heat is increasing. In order to dissipate heat, the insulating layer of the printed multilayer wiring board needs to have a high thermal conductivity.

  In addition, in order to suppress the warpage of the substrate laminated on the insulating layer, due to the difference in thermal expansion coefficient between the insulating layer and the conductor layer, the solder layer used for the insulating layer, conductor layer, or bonding In order to suppress the occurrence of cracks, the insulating layer needs to have a low coefficient of thermal expansion.

  However, when the insulating layer of the printed multilayer wiring board is formed using a conventional insulating material, the thermal linear expansion coefficient of the insulating layer is relatively high, so that the substrate laminated on the insulating layer may be warped. . Furthermore, the heat resistance of the insulating layer may not be sufficient.

  Furthermore, the insulating material for forming the insulating layer described in Patent Documents 1 and 2 is not a sheet itself having a self-supporting property in an uncured state, and has low handling properties.

  Even when a conventional sheet-like insulating material is used, the handling property of the insulating material may be low, the thermal expansion coefficient of the insulating layer may be relatively high, or the heat resistance of the insulating layer may be low. In particular, when the filler is filled at a high density in order to improve the heat dissipation property of the insulating layer, the sheet-like insulating material becomes hard and brittle, and the handling property of the sheet-like insulating material may be lowered.

  An object of the present invention is to provide an insulating sheet that can obtain a cured product having high handling properties in an uncured state and high heat resistance, and that can suppress warping of the laminate laminated on the cured product, and the insulating sheet. It is to provide a laminated structure used and a method for producing the laminated structure.

  The limited object of this invention is to provide the insulating sheet which can improve the heat dissipation of hardened | cured material, the laminated structure using this insulating sheet, and the manufacturing method of a laminated structure.

  According to a wide aspect of the present invention, there is provided an insulating sheet containing a polymer having a diphenylene sulfone group, a curable compound having an epoxy group or an oxetane group, a curing agent, and a filler.

  In a specific aspect of the insulating sheet according to the present invention, the polymer is soluble in an organic solvent.

  When the insulating sheet according to the present invention is cured, the cured product has a thermal conductivity of 0.5 W / m · K or more, and the cured product has an average coefficient of linear thermal expansion at 25 to 100 ° C. of 20 ppm / ° C. or less. It is preferable that the 1 GHz relative dielectric constant is 5 or less.

  In another specific aspect of the insulating sheet according to the present invention, the curing agent is a phenol resin, an acid anhydride having an aromatic skeleton or an alicyclic skeleton, a water additive of the acid anhydride, or the acid anhydride. It is a modified product.

  In still another specific aspect of the insulating sheet according to the present invention, the curing agent is an acid anhydride having a polyalicyclic skeleton, a water additive of the acid anhydride or a modified product of the acid anhydride, or a terpene. An acid anhydride having an alicyclic skeleton obtained by an addition reaction between a system compound and maleic anhydride, a water additive of the acid anhydride, or a modified product of the acid anhydride.

  In still another specific aspect of the insulating sheet according to the present invention, the curing agent is an acid anhydride represented by any of the following formulas (1) to (4).

  In said formula (4), R1 and R2 show hydrogen, a C1-C5 alkyl group, or a hydroxyl group, respectively.

  In still another specific aspect of the insulating sheet according to the present invention, the curing agent is a phenol resin having a melamine skeleton or a triazine skeleton, or a phenol resin having an allyl group.

  The filler is preferably at least one selected from the group consisting of silica, alumina, boron nitride, aluminum nitride, silicon nitride, silicon carbide, zinc oxide, magnesite and magnesium oxide. In 100% by volume of the insulating sheet, the filler content is preferably in the range of 30 to 90% by volume. The filler is preferably spherical. The filler is preferably treated with a coupling agent.

  The laminated structure according to the present invention includes a substrate having a first conductor layer on at least one surface and having a through hole or a concave portion on the one surface, and the one surface or both surfaces of the substrate. A laminated insulating layer; and a second conductor layer or circuit board laminated on a surface of the insulating layer opposite to the surface on which the substrate is laminated, wherein the insulating layer is configured according to the present invention. It is formed by curing an insulating sheet.

  In a specific aspect of the multilayer structure according to the present invention, at least one of the first conductor layer and the second conductor layer is a wiring circuit.

  The multilayer structure according to the present invention is preferably a multilayer circuit board having two or more conductor layers. Furthermore, the laminated structure according to the present invention is preferably a multilayer circuit board used for a chip size package.

  The method for producing a laminated structure according to the present invention has the first conductor layer on at least one surface, and the one surface or both surfaces of the substrate having a through hole or a recess on the one surface, The step of laminating the insulating sheet configured according to the present invention so that a part of the insulating sheet is filled in the through-hole or the recess, and the surface of the laminated insulating sheet on which the substrate is disposed A step of laminating a conductor layer or a circuit board on the opposite surface and a step of curing the insulating sheet are provided.

  Since the insulating sheet according to the present invention contains a polymer having a diphenylene sulfone group, a curable compound having an epoxy group or an oxetane group, a curing agent, and a filler, the handling property in an uncured state is high. Furthermore, the heat resistance of the hardened | cured material of an insulating sheet can be improved, and the curvature of laminated bodies, such as a board | substrate or a semiconductor chip laminated | stacked on the hardened | cured material of the insulating sheet, can be suppressed.

  Furthermore, the insulating sheet according to the present invention has high handling properties in an uncured state even when the filler is filled with a high density in order to enhance the heat dissipation of the cured product. Therefore, the heat dissipation of the hardened | cured material of an insulating sheet can also be improved.

FIG. 1 is a partially cutaway front sectional view schematically showing a laminated structure according to an embodiment of the present invention. FIG. 2 is a partially cutaway front sectional view schematically showing a laminated structure according to another embodiment of the present invention.

  Details of the present invention will be described below.

  The insulating sheet according to the present invention contains a polymer (A) having a diphenylene sulfone group, a curable compound (B) having an epoxy group or an oxetane group, a curing agent (C), and a filler (D). . By adopting the above composition, it is possible to improve the handleability of the insulating sheet in an uncured state, to obtain a cured product having excellent heat resistance, and to further warp the laminate laminated on the cured product of the insulating sheet. Can be suppressed.

  Further, when a polymer having a diphenylene sulfone group is used, when the filler is filled at a high density, the insulating sheet tends to be hard and brittle. However, since the specific component is used together with the polymer (A) having a diphenylene sulfone group, the insulating sheet is hard and hard to be brittle, and the handling properties of the insulating sheet can be improved.

  Moreover, by adopting the above composition, the thermal conductivity of the cured product of the insulating sheet is 0.5 W / m · K or more, the average thermal linear expansion coefficient of the cured product at 25 to 100 ° C. is 20 ppm / ° C. or less, and the cured product The relative dielectric constant at 1 GHz can be made 5 or less.

  Furthermore, in the insulating sheet having the above composition, the filler (D) content in 100% by volume of the insulating sheet is 1% by volume or more, or the filler (D) having a thermal conductivity of 10 W / m · K or more is used. By doing, the heat dissipation of the hardened | cured material of an insulating sheet can be made high. Moreover, since the insulating sheet which concerns on this invention has the said composition, it can be filled with a filler (D) with high density.

(Polymer (A))
The polymer (A) contained in the insulating sheet according to the present invention is not particularly limited as long as it has a diphenylene sulfone group. As for a polymer (A), only 1 type may be used and 2 or more types may be used together.

  Examples of the polymer (A) include polyethersulfone, polysulfone, and polyarylsulfone. From the viewpoint of increasing the solubility in a solvent during the production of the insulating sheet, the molecular chain of the polymer (A) is preferably linear.

  The polymer (A) is preferably soluble in an organic solvent. In this case, the handleability of the insulating sheet in an uncured state can be further enhanced. The boiling point of the organic solvent is preferably 100 ° C. or lower. The polymer (A) is preferably soluble in methyl ethyl ketone, which is an organic solvent. The polymer (A) is preferably soluble in an organic solvent at 23 ° C.

  The weight average molecular weight of the polymer (A) is preferably 10,000 or more. The preferred lower limit of the weight average molecular weight of the polymer (A) is 30,000, the more preferred lower limit is 40,000, the still more preferred lower limit is 100,000, the preferred upper limit is 1,000,000, and the more preferred upper limit is 250,000. If the weight average molecular weight of a polymer (A) satisfy | fills the said preferable minimum, the heat resistance of the hardened | cured material of an insulating sheet can be improved further. When the weight average molecular weight of the polymer (A) satisfies the above preferable upper limit, the compatibility between the polymer (A) and another resin is increased. As a result, the handling property of the insulating sheet in the uncured state and the heat resistance of the cured product can be further enhanced.

  In a total of 100% by weight of the total resin components (hereinafter sometimes abbreviated as total resin component X) contained in the insulating sheet containing the polymer (A), the curable compound (B) and the curing agent (C), The content of the polymer (A) is preferably in the range of 20 to 60% by weight. The more preferable lower limit of the content of the polymer (A) in the total 100% by weight of all the resin components X is 30% by weight, and the more preferable upper limit is 50% by weight. When content of a polymer (A) satisfy | fills the said preferable minimum, the handleability of the insulating sheet in a non-hardened state can be improved further. When content of a polymer (A) satisfy | fills the said preferable upper limit, dispersion | distribution of a filler (D) will become easy. The total resin component X refers to the total of the polymer (A), the curable compound (B), the curing agent (C), and other resin components added as necessary. The total resin component X does not contain the filler (D).

(Curable compound (B))
The curable compound (B) contained in the insulating sheet according to the present invention is not particularly limited as long as it has an epoxy group or an oxetane group. As for a curable compound (B), only 1 type may be used and 2 or more types may be used together.

  The curable compound (B) may be a curable compound (B1) having an epoxy group or a curable compound (B2) having an oxetane group.

  From the viewpoint of further reducing the average thermal linear expansion coefficient of the cured product of the insulating sheet, the curable compound (B) preferably has two or more epoxy groups or oxetane groups, and more preferably three or more.

  From the viewpoint of further improving the heat resistance and dielectric breakdown characteristics of the cured product of the insulating sheet, the curable compound (B) preferably has an aromatic skeleton.

  The curable compound (B1) having an epoxy group is not particularly limited. As the curable compound (B1), an epoxy monomer (B1b) having an aromatic skeleton and having a weight average molecular weight of 600 or less is suitably used.

  Specific examples of the curable compound (B1) having an epoxy group include an epoxy monomer having a bisphenol skeleton, an epoxy monomer having a dicyclopentadiene skeleton, an epoxy monomer having a naphthalene skeleton, an epoxy monomer having an adamantene skeleton, and a fluorene skeleton. Examples include an epoxy monomer, an epoxy monomer having a biphenyl skeleton, an epoxy monomer having a bi (glycidyloxyphenyl) methane skeleton, an epoxy monomer having a xanthene skeleton, an epoxy monomer having an anthracene skeleton, and an epoxy monomer having a pyrene skeleton. As for a sclerosing | hardenable compound (B1), only 1 type may be used and 2 or more types may be used together.

  Examples of the epoxy monomer having a bisphenol skeleton include an epoxy monomer having a bisphenol A type, bisphenol F type, or bisphenol S type bisphenol skeleton.

  Examples of the epoxy monomer having a dicyclopentadiene skeleton include dicyclopentadiene dioxide and a phenol novolac epoxy monomer having a dicyclopentadiene skeleton.

  Examples of the epoxy monomer having a naphthalene skeleton include 1-glycidylnaphthalene, 2-glycidylnaphthalene, 1,2-diglycidylnaphthalene, 1,5-diglycidylnaphthalene, 1,6-diglycidylnaphthalene, 1,7-diglycidyl. Naphthalene, 2,7-diglycidylnaphthalene, triglycidylnaphthalene, 1,2,5,6-tetraglycidylnaphthalene and the like can be mentioned.

  Examples of the epoxy monomer having an adamantene skeleton include 1,3-bis (4-glycidyloxyphenyl) adamantene and 2,2-bis (4-glycidyloxyphenyl) adamantene.

  Examples of the epoxy monomer having a fluorene skeleton include 9,9-bis (4-glycidyloxyphenyl) fluorene, 9,9-bis (4-glycidyloxy-3-methylphenyl) fluorene, and 9,9-bis (4- Glycidyloxy-3-chlorophenyl) fluorene, 9,9-bis (4-glycidyloxy-3-bromophenyl) fluorene, 9,9-bis (4-glycidyloxy-3-fluorophenyl) fluorene, 9,9-bis (4-Glycidyloxy-3-methoxyphenyl) fluorene, 9,9-bis (4-glycidyloxy-3,5-dimethylphenyl) fluorene, 9,9-bis (4-glycidyloxy-3,5-dichlorophenyl) Fluorene and 9,9-bis (4-glycidyloxy-3,5-dibromophenyl) Fluorene, and the like.

  Examples of the epoxy monomer having a biphenyl skeleton include 4,4'-diglycidylbiphenyl and 4,4'-diglycidyl-3,3 ', 5,5'-tetramethylbiphenyl.

  Examples of the epoxy monomer having a bi (glycidyloxyphenyl) methane skeleton include 1,1′-bi (2,7-glycidyloxynaphthyl) methane, 1,8′-bi (2,7-glycidyloxynaphthyl) methane, 1,1′-bi (3,7-glycidyloxynaphthyl) methane, 1,8′-bi (3,7-glycidyloxynaphthyl) methane, 1,1′-bi (3,5-glycidyloxynaphthyl) methane 1,8'-bi (3,5-glycidyloxynaphthyl) methane, 1,2'-bi (2,7-glycidyloxynaphthyl) methane, 1,2'-bi (3,7-glycidyloxynaphthyl) Examples include methane and 1,2′-bi (3,5-glycidyloxynaphthyl) methane.

  Examples of the epoxy monomer having a xanthene skeleton include 1,3,4,5,6,8-hexamethyl-2,7-bis-oxiranylmethoxy-9-phenyl-9H-xanthene.

  The curable compound (B2) having an oxetane group is not particularly limited. As the curable compound (B2), an oxetane monomer (B2b) having an aromatic skeleton and having a weight average molecular weight of 600 or less is suitably used.

  Specific examples of the curable compound (B2) having an oxetane group include, for example, 4,4′-bis [(3-ethyl-3-oxetanyl) methoxymethyl] biphenyl, 1,4-benzenedicarboxylate bis [(3 -Ethyl-3-oxetanyl) methyl] ester, 1,4-bis [(3-ethyl-3-oxetanyl) methoxymethyl] benzene, oxetated phenol novolak, and the like. As for a sclerosing | hardenable compound (B2), only 1 type may be used and 2 or more types may be used together.

  The weight average molecular weight of the curable compound (B) is preferably less than 10,000. The weight average molecular weight of the curable compound (B) is preferably 600 or less. The preferable lower limit of the weight average molecular weight of the curable compound (B) is 200, and the more preferable upper limit is 550. When the weight average molecular weight of the curable compound (B) satisfies the above preferable lower limit, the volatile property of the curable compound (B) is lowered, and the handleability of the insulating sheet is further enhanced. When the weight average molecular weight of the curable compound (B) satisfies the preferable upper limit, the insulating sheet is hard and not easily brittle, and the adhesiveness of the cured product of the insulating sheet can be further enhanced.

  The content of the curable compound (B) is preferably in the range of 10 to 60% by weight in 100% by weight of the total resin component X. The more preferable lower limit of the content of the curable compound (B) in the total 100% by weight of all the resin components X is 10% by weight, and the more preferable upper limit is 40% by weight. The curable compound (B) is preferably contained so that the total content of the polymer (A) and the curable compound (B) is less than 100% by weight within the above range. When content of a sclerosing | hardenable compound (B) satisfy | fills the said preferable minimum, the adhesiveness and heat resistance of the hardened | cured material of an insulating sheet can be improved further. When content of a sclerosing | hardenable compound (B) satisfy | fills the said preferable upper limit, the handleability of the insulating sheet in a non-hardened state can be improved further.

(Curing agent (C))
The curing agent (C) contained in the insulating sheet according to the present invention is not particularly limited as long as it cures the insulating sheet. As for a hardening | curing agent (C), only 1 type may be used and 2 or more types may be used together.

  The curing agent (C) is preferably a phenol resin, or an acid anhydride having an aromatic skeleton or an alicyclic skeleton, a water additive of the acid anhydride, or a modified product of the acid anhydride. By using this preferable curing agent (C), a cured product of an insulating sheet having an excellent balance of heat resistance, moisture resistance and electrical properties can be obtained.

  The phenol resin is not particularly limited. Specific examples of the phenol resin include phenol novolak, o-cresol novolak, p-cresol novolak, t-butylphenol novolak, dicyclopentadiene cresol, polyparavinylphenol, bisphenol A type novolak, xylylene modified novolak, decalin modified novolak, Examples include poly (di-o-hydroxyphenyl) methane, poly (di-m-hydroxyphenyl) methane, and poly (di-p-hydroxyphenyl) methane. Especially, since the softness | flexibility and flame retardance of an insulating sheet can be improved further, the phenol resin which has a melamine skeleton, the phenol resin which has a triazine skeleton, or the phenol resin which has an allyl group is preferable.

  Commercially available products of the phenol resin include MEH-8005, MEH-8010 and NEH-8015 (all of which are manufactured by Meiwa Kasei Co., Ltd.), YLH903 (manufactured by Japan Epoxy Resin Co., Ltd.), LA-7052, LA-7054, and LA-7751. LA-1356 and LA-3018-50P (all manufactured by DIC), PS6313 and PS6492 (manufactured by Gunei Chemical Co., Ltd.), and the like.

  An acid anhydride having an aromatic skeleton, a water additive of the acid anhydride, or a modified product of the acid anhydride is not particularly limited. Examples of the acid anhydride having an aromatic skeleton, a water addition of the acid anhydride, or a modified product of the acid anhydride include, for example, a styrene / maleic anhydride copolymer, benzophenone tetracarboxylic acid anhydride, pyromellitic acid anhydride, Trimellitic anhydride, 4,4'-oxydiphthalic anhydride, phenylethynylphthalic anhydride, glycerol bis (anhydrotrimellitate) monoacetate, ethylene glycol bis (anhydrotrimellitate), methyltetrahydrophthalic anhydride Examples include acid, methylhexahydrophthalic anhydride, and trialkyltetrahydrophthalic anhydride. Of these, methyl nadic acid anhydride or trialkyltetrahydrophthalic anhydride is preferable. The use of methyl nadic acid anhydride or trialkyltetrahydrophthalic anhydride can increase the water resistance of the cured product of the insulating sheet.

  Examples of commercially available acid anhydrides having an aromatic skeleton, water additives of the acid anhydrides, or modified products of the acid anhydrides include SMA Resin EF30, SMA Resin EF40, SMA Resin EF60, and SMA Resin EF80. Also manufactured by Sartomer Japan), ODPA-M and PEPA (all of which are manufactured by Manac), Rikagit MTA-10, Rikagit MTA-15, Rikagit TMTA, Rikagit TMEG-100, Rikagit TMEG-200, Rikagit TMEG-300, Rikagit TMEG-500, Rikagit TMEG-S, Rikagit TH, Rikagit HT-1A, Rikagit HH, Rikagit MH-700, Rikagit MT-500, Rikagit DSDA and Rikagit TDA-100 (all of which are manufactured by Shin Nippon Rika Co., Ltd.), and PICLON B4400, EPICLON B650, and EPICLON B570 (all manufactured by both DIC Corporation).

  The acid anhydride having an alicyclic skeleton, a water additive of the acid anhydride, or a modified product of the acid anhydride is an acid anhydride having a polyalicyclic skeleton, a water additive of the acid anhydride, or the A modified product of an acid anhydride, or an acid anhydride having an alicyclic skeleton obtained by addition reaction of a terpene compound and maleic anhydride, a water additive of the acid anhydride, or a modified product of the acid anhydride It is preferable. In this case, the flexibility, moisture resistance or adhesion of the insulating sheet can be further enhanced. Examples of the acid anhydride having the alicyclic skeleton, a water addition of the acid anhydride, or a modified product of the acid anhydride include methyl nadic acid anhydride, acid anhydride having a dicyclopentadiene skeleton, and the acid. Examples of the modified product include anhydrides.

  Examples of commercially available acid anhydrides having the alicyclic skeleton, water additions of the acid anhydrides, or modified products of the acid anhydrides include Rikagit HNA and Rikagit HNA-100 (all manufactured by Shin Nippon Rika Co., Ltd.) , And EpiCure YH306, EpiCure YH307, EpiCure YH308H, EpiCure YH309 (all of which are manufactured by Japan Epoxy Resin Co., Ltd.) and the like.

  The curing agent (C) is more preferably an acid anhydride represented by any of the following formulas (1) to (4). By using this preferable curing agent (C), the flexibility, moisture resistance or adhesion of the insulating sheet can be further enhanced.

  In said formula (4), R1 and R2 show hydrogen, a C1-C5 alkyl group, or a hydroxyl group, respectively.

  In order to adjust the curing speed or the physical properties of the cured product, the curing agent and the curing accelerator may be used in combination.

  The said hardening accelerator is not specifically limited. Specific examples of the curing accelerator include tertiary amines, imidazoles, imidazolines, triazines, organic phosphorus compounds, quaternary phosphonium salts and diazabicycloalkenes such as organic acid salts. Examples of the curing accelerator include organometallic compounds, quaternary ammonium salts, metal halides, and the like. Examples of the organometallic compounds include zinc octylate, tin octylate and aluminum acetylacetone complex.

  Examples of the curing accelerator include a high melting point imidazole curing accelerator, a high melting point dispersion type latent curing accelerator, a microcapsule type latent curing accelerator, an amine salt type latent curing accelerator, and a high temperature dissociation type and thermal cation. A polymerization type latent curing accelerator or the like can be used. As for the said hardening accelerator, only 1 type may be used and 2 or more types may be used together.

  Examples of the high melting point dispersion type latent accelerator include dicyandiamide and amine addition type accelerators in which an amine is added to an epoxy monomer or the like. Examples of the microcapsule type latent accelerator include a microcapsule type latent accelerator in which the surface of an imidazole, phosphorus or phosphine accelerator is coated with a polymer. Examples of the high temperature dissociation type and thermal cationic polymerization type latent curing accelerator include Lewis acid salt or Bronsted acid salt.

  The curing accelerator is preferably a high melting point imidazole curing accelerator. By using a high melting point imidazole-based curing accelerator, the reaction system can be easily controlled, and the curing speed of the insulating sheet and the physical properties of the cured product of the insulating sheet can be more easily adjusted. A high-melting-point curing accelerator having a melting point of 100 ° C. or higher is excellent in handleability. Accordingly, the melting accelerator preferably has a melting point of 100 ° C. or higher.

  The content of the curing agent (C) is preferably in the range of 10 to 40% by weight in 100% by weight of the total resin component X. In a total of 100% by weight of all resin components X, the more preferable lower limit of the content of the curing agent (C) is 12% by weight, the still more preferable lower limit is 15% by weight, the more preferable upper limit is 40% by weight, and the more preferable upper limit is 25% by weight. %. When the content of the curing agent (C) satisfies the above preferable lower limit, it is easy to sufficiently cure the insulating sheet. When content of a hardening | curing agent (C) satisfy | fills the said preferable upper limit, it will become difficult to generate | occur | produce the excessive hardening | curing agent which does not participate in hardening, and bridge | crosslinking of hardened | cured material can fully advance. For this reason, the heat resistance and adhesiveness of the hardened | cured material of an insulating sheet can be improved further.

(Filler (D))
By including the filler (D) in the insulating sheet according to the present invention, the thermal conductivity of the cured product of the insulating sheet can be increased. As a result, the heat dissipation of the cured product of the insulating sheet is increased. As for a filler (D), only 1 type may be used and 2 or more types may be used together.

  The filler (D) may be an inorganic filler or an organic filler. From the viewpoint of further improving the heat dissipation of the cured product, the filler (D) is preferably an inorganic filler. From the viewpoint of further improving the heat dissipation of the cured product, the filler (D) was selected from the group consisting of silica, alumina, boron nitride, aluminum nitride, silicon nitride, silicon carbide, zinc oxide, magnesite and magnesium oxide. It is preferable that there is at least one.

  From the viewpoint of further improving the heat dissipation of the cured product of the insulating sheet, the thermal conductivity of the filler (D) is preferably 10 W / m · K or more. From the viewpoint of further improving the heat dissipation of the cured product, the preferred lower limit of the thermal conductivity of the filler (D) is 15 W / m · K, and the more preferred lower limit is 20 W / m · K. The upper limit of the thermal conductivity of the filler (D) is not particularly limited. Inorganic fillers having a thermal conductivity of about 300 W / m · K are widely known, and inorganic fillers having a thermal conductivity of about 200 W / m · K are easily available.

  The filler (D) is particularly preferably spherical. In the case of a spherical filler, since the filler (D) can be filled at a high density, the heat dissipation of the cured product of the insulating sheet can be further enhanced.

  The average particle diameter of the filler (D) is preferably in the range of 0.1 to 40 μm. When the average particle size is 0.1 μm or more, it becomes easy to fill the filler (D) at a high density. When the average particle diameter is 40 μm or less, the dielectric breakdown characteristics of the cured product of the insulating sheet can be further enhanced.

  The “average particle diameter” is an average particle diameter obtained from a volume average particle size distribution measurement result measured by a laser diffraction particle size distribution measuring apparatus.

  From the viewpoint of increasing the dispersibility of the filler (D) and further improving the heat dissipation of the cured product of the insulating sheet, the filler (D) is preferably treated with a coupling agent.

  Examples of the coupling agent include silane coupling agents, titanate coupling agents, and aluminum coupling agents. Of these, a silane coupling agent is preferable. Examples of the silane coupling agent include silane compounds having an amino group, silane compounds having a mercapto group, silane compounds having an isocyanate group, silane compounds having an acid anhydride group, and silane compounds having an isocyanuric acid group.

  In 100% by volume of the insulating sheet, the filler (D) content is preferably in the range of 20 to 90% by volume. When content of a filler (D) exists in the said range, the heat dissipation of the hardened | cured material of an insulating sheet can be made high. A more preferable lower limit of the content of the filler (D) in 100% by volume of the insulating sheet is 30% by volume, a further preferable lower limit is 35% by volume, a more preferable upper limit is 85% by volume, and a further preferable upper limit is 80% by volume. When content of a filler (D) satisfy | fills the said preferable minimum, the heat dissipation of hardened | cured material can be improved further, and also the thermal expansion coefficient of hardened | cured material can be made still lower. When content of a filler (D) satisfy | fills the said preferable upper limit, an insulating sheet will have further moderate fluidity | liquidity, and it will become easy to fully fill an insulating sheet in a circuit or a via hole. Furthermore, the adhesiveness of an insulating sheet can fully be improved.

(Other ingredients)
The insulating sheet according to the present invention may contain rubber particles. By using the rubber particles, the stress relaxation property and flexibility of the cured product of the insulating sheet can be enhanced.

  The insulating sheet according to the present invention may contain a dispersant. By using the dispersant, the thermal conductivity and dielectric breakdown characteristics of the cured product of the insulating sheet can be further enhanced.

  The dispersant preferably has a functional group containing a hydrogen atom having hydrogen bonding properties. When the dispersing agent has a functional group containing a hydrogen atom having hydrogen bonding properties, the thermal conductivity and dielectric breakdown characteristics of the cured product of the insulating sheet can be further enhanced. Examples of the functional group containing a hydrogen atom having hydrogen bonding include a carboxyl group (pKa = 4), a phosphate group (pKa = 7), a phenol group (pKa = 10), and the like.

  The preferable lower limit of pKa of the functional group containing a hydrogen atom having hydrogen bonding properties is 2, a more preferable lower limit is 3, a preferable upper limit is 10, and a more preferable upper limit is 9. When the pKa of the functional group satisfies the preferable lower limit, the acidity of the dispersant does not become too high. Therefore, the storage stability of the insulating sheet can be further enhanced. When pKa of the said functional group satisfy | fills the said preferable upper limit, the function as the said dispersing agent will fully be fulfilled and the heat conductivity and dielectric breakdown characteristic of the hardened | cured material of an insulating sheet can be improved further.

  The functional group containing a hydrogen atom having hydrogen bonding properties is preferably a carboxyl group or a phosphate group. In this case, the thermal conductivity and dielectric breakdown characteristics of the cured product of the insulating sheet can be further enhanced.

  Specific examples of the dispersant include a polyester carboxylic acid, a polyether carboxylic acid, a polyacrylic carboxylic acid, an aliphatic carboxylic acid, a polysiloxane carboxylic acid, a polyester phosphoric acid, and a polyether type. Examples thereof include phosphoric acid, polyacrylic phosphoric acid, aliphatic phosphoric acid, polysiloxane phosphoric acid, polyester phenol, polyether phenol, polyacrylic phenol, aliphatic phenol, and polysiloxane phenol. As for the said dispersing agent, only 1 type may be used and 2 or more types may be used together.

  In 100% by weight of the insulating fat sheet, a preferable lower limit of the content of the dispersant is 0.01% by weight, a more preferable lower limit is 0.1% by weight, a preferable upper limit is 20% by weight, and a more preferable upper limit is 10% by weight. . When content of the said dispersing agent satisfy | fills the said preferable minimum and upper limit, aggregation of a filler (D) can be suppressed and the heat dissipation and dielectric breakdown characteristic of the hardened | cured material of an insulating sheet can be improved further.

  The insulating sheet according to the present invention may contain a base material such as glass cloth, glass nonwoven fabric, and aramid nonwoven fabric in order to further improve handling properties. However, even if it does not contain the said base material, the insulating sheet which concerns on this invention has self-supporting property at room temperature (23 degreeC), and has the outstanding handling property. Therefore, the insulating sheet preferably does not contain a base material, and particularly preferably does not contain glass cloth. When an insulating sheet does not contain the said base material, the thickness of an insulating sheet can be made thin and the thermal conductivity of the hardened | cured material of an insulating sheet can be improved further. Furthermore, when an insulating sheet does not contain the said base material, various processes, such as a laser processing or a drill drilling process, can also be easily performed to the hardened | cured material of an insulating sheet as needed. In addition, self-supporting means that the shape of a sheet can be maintained and handled as a sheet even when a support such as a PET film or a copper foil is not present.

  Moreover, the insulating sheet according to the present invention may contain a tackifier, a plasticizer, a curing agent, a coupling agent, a thixotropic agent, a flame retardant, a colorant, and the like as necessary.

(Insulating sheet)
The manufacturing method of the insulating sheet which concerns on this invention is not specifically limited. The insulating sheet can be obtained, for example, by forming a mixture obtained by mixing the above-described materials into a sheet shape by a method such as a solvent casting method or an extrusion film forming method. Defoaming is preferred when forming into a sheet.

  The thickness of the insulating sheet is not particularly limited. The thickness of the insulating sheet is preferably in the range of 10 to 300 μm. A more preferable lower limit of the thickness of the insulating sheet is 50 μm, a further preferable lower limit is 70 μm, a more preferable upper limit is 200 μm, and a further preferable upper limit is 120 μm. When the thickness of the insulating sheet satisfies the preferable lower limit, the insulating property of the cured product of the insulating sheet becomes high. When the thickness of the insulating sheet satisfies the above preferable upper limit, the heat dissipation of the cured product of the insulating sheet is further enhanced.

  The glass transition temperature Tg of the insulating sheet is preferably 25 ° C. or lower. When the glass transition temperature is 25 ° C. or lower, the insulating sheet is hard and not easily brittle at room temperature. For this reason, the handleability of the insulating sheet in an uncured state can be further enhanced.

  The heat conductivity of the cured product of the insulating sheet is preferably 0.5 W / m · K or more. The thermal conductivity of the cured product of the insulating sheet is preferably 1.0 W / m · K or more, more preferably 1.5 W / m · K or more, and 2.0 W / m · K or more. More preferably. The higher the thermal conductivity, the higher the heat dissipation of the cured product of the insulating sheet.

  It is preferable that the average thermal linear expansion coefficient in 25-100 degreeC of the hardened | cured material of an insulating sheet is 20 ppm / degrees C or less. The average thermal expansion coefficient at 25 to 100 ° C. of the cured product of the insulating sheet is preferably 15 ppm / ° C. or less, and more preferably 10 ppm / ° C. or less. As the average thermal linear expansion coefficient is lower, the difference in thermal linear expansion coefficient between the cured product of the insulating sheet and the substrate or semiconductor chip becomes smaller, and the substrate or semiconductor chip laminated on the cured product of the insulating sheet is less likely to warp. Furthermore, during solder reflow or a cold / heat cycle test, cracks or peeling at the solder layer used for the insulating layer, conductor layer, or bonding is less likely to occur.

  The dielectric constant at 1 GHz of the cured product of the insulating sheet is preferably 5 or less. The relative dielectric constant at 1 GHz of the cured product of the insulating sheet is preferably 4 or less, and more preferably 3.5 or less. The smaller the relative dielectric constant, the lower the transmission loss and the higher the reliability of the electric signal.

  The dielectric breakdown voltage of the cured product of the insulating sheet is preferably 30 kV / mm or more, more preferably 40 kV / mm or more, further preferably 50 kV / mm or more, and 80 kV / mm or more. Is more preferably 100 kV / mm or more. The higher the dielectric breakdown voltage, the higher the insulation is when the cured product of the insulating sheet is used for a large current application such as for power elements.

(Use of insulation sheet)
The insulating sheet according to the present invention is used to form an insulating layer on the surface of a substrate having a through hole or a concave portion on the surface. The insulating sheet according to the present invention is suitably used for forming an insulating layer on the surface of a substrate having a through hole. When the insulating layer is formed on the surface of the substrate, an insulating sheet is laminated on the surface of the substrate. At this time, a part of the insulating sheet is filled in the through hole or the recess.

  The insulating sheet according to the present invention includes a substrate having a first conductor layer on at least one surface and having a through hole or a recess on one surface, and an insulating layer laminated on one surface or both surfaces of the substrate. It is suitably used to construct a laminated structure comprising a layer and a second conductor layer or circuit board laminated on the surface opposite to the surface on which the substrate of the insulating layer is laminated. The insulating layer of the laminated structure is formed by curing an insulating sheet configured according to the present invention.

  In FIG. 1, the laminated structure which concerns on one Embodiment of this invention is typically shown with a partial notch front sectional drawing.

  A laminated structure 1 shown in FIG. 1 includes a substrate 2 having a via hole 2a as a through hole. A conductor layer 2 b is formed on the surface of the substrate 2. The conductor layer 2b is formed on the upper surface 2c and the lower surface 2d of the substrate 2 and the inner peripheral surface of the via hole 2a. Insulating layers 3 and 4 are laminated on the upper surface 2 c and the lower surface 2 d of the substrate 2. The insulating layers 3 and 4 are filled in the via holes 2 a of the substrate 2. An insulating layer 6 is laminated on the upper surface 3 a of the insulating layer 3 with a conductor layer 5 interposed therebetween. On the insulating layer 6, a conductor layer 7 is laminated. A conductor layer 8 is laminated on the lower surface 4 a of the insulating layer 4.

  The conductor layer 2b, the conductor layer 5, and the conductor layer 7 are connected by via hole connection (not shown). The conductor layer 2b and the conductor layer 8 are connected by via hole connection (not shown). In order to form a via hole in the insulating layer or the conductor layer, various operations necessary for forming the multilayer circuit board such as drilling or plating may be performed.

  The laminated structure 1 can be formed by laminating an insulating sheet on the upper surface 2c and the lower surface 2d of the substrate 2 so that a part of the insulating sheet is filled in the via hole 2a. Moreover, after laminating an insulating sheet on the surface of the substrate 2, a conductor layer is formed on the insulating sheet as necessary. Furthermore, an insulating layer is formed on the conductor layer as necessary.

  FIG. 2 schematically shows a laminated structure according to another embodiment of the present invention in a partially cutaway front sectional view.

  In the laminated structure 11 shown in FIG. 2, a plurality of insulating layers 13 to 15 are laminated on the upper surface 12 a of the substrate 12. The substrate 12 has a conductor layer 12b in a partial region of the upper surface 12a. A recess 12c is formed in the upper surface 12a of the substrate 12 by a conductor layer 12b. The insulating layers 13 and 14 other than the uppermost insulating layer 15 have conductor layers 13b and 14b in partial regions of the upper surfaces 13a and 14a. Concave portions 13c and 14c are formed on the upper surfaces 13a and 14a of the insulating layers 13 and 14 by the conductor layers 13b and 14b. The insulating layers 13 to 15 are filled in the recesses 12c to 14c. The conductor layers 12b to 14b are connected by via hole connection (not shown).

  The laminated structure 11 can be formed by laminating an insulating sheet on the upper surface 12a of the substrate 12 so that a part of the insulating sheet is filled in the recess 12c. In addition, after an insulating sheet is laminated on the upper surface 12a of the substrate 12, a conductor layer is formed on the insulating sheet as necessary. Furthermore, an insulating layer is formed on the conductor layer as necessary.

  The substrate is preferably a substrate having a first conductor layer on at least one surface and having a through hole. When the insulating sheet according to the present invention is used, when the insulating sheet is laminated on the substrate having the through hole, a part of the insulating sheet can be sufficiently filled in the through hole of the substrate. The through hole is preferably a via hole.

  At least one of the first conductor layer and the second conductor layer is preferably a wiring circuit. When the first and second conductor layers are wiring circuits, a plurality of recesses are formed on the surface of the substrate. The recess is preferably a circuit recess. When the insulating sheet according to the present invention is used, when the insulating sheet is laminated on the substrate having the concave portion on the surface, a part of the insulating sheet can be sufficiently filled in the concave portion of the substrate. In addition, since the average thermal linear expansion coefficient of the insulating layer is low and the difference in thermal expansion coefficient between the conductor layer and the insulating layer is small, the occurrence of cracks can be suppressed.

  The multilayer structure according to the present invention is preferably a multilayer circuit board having two or more conductor layers. The laminated structure according to the present invention is preferably a multilayer circuit board used for a chip size package. Since the average thermal linear expansion coefficient of the insulating layer is low, even if the multilayer circuit board is a circuit board used for a chip size package, the occurrence of cracks in the solder layer used for the insulating layer, conductor layer, or bonding can be suppressed. .

  When the semiconductor mounting method is a chip size package, it is required to increase the density of the wiring circuit and reduce the thickness of the circuit. In such a case, the insulating sheet according to the present invention is suitably used.

  The laminated structure can be manufactured as follows, for example.

  An insulating sheet is provided on one or both surfaces of a substrate having a first conductor layer on at least one surface and having a through hole or a recess on one surface, and a part of the insulating sheet is a through hole or Lamination is performed so that the recess is filled. Next, a second conductor layer or a circuit board is laminated on the surface of the insulating sheet opposite to the surface on which the substrate is laminated. Thereafter, the insulating sheet is cured.

  Hereinafter, the present invention will be clarified by giving specific examples and comparative examples of the present invention. The present invention is not limited to the following examples.

  The following materials were prepared.

[Polymer (A)]
(1) Polyethersulfone 1 (soluble in methyl ethyl ketone as an organic solvent at 23 ° C., manufactured by Sumitomo Chemical Co., Ltd., trade name: PES5003P)
(2) Polyethersulfone 2 (soluble in methyl ethyl ketone as an organic solvent at 23 ° C., manufactured by Solven Advanced Polymers, Inc., trade name: P1700)
(3) Polyethersulfone 3 (soluble in methyl ethyl ketone as an organic solvent at 23 ° C., manufactured by BASF Japan, trade name: Ultra Zone E)
[Polymers other than polymer (A)]
(1) Acrylic polymer (trade name: UC-3000, Mw = 10,000, manufactured by Toa Gosei Co., Ltd.)

[Curable compound (B)]
(1) Bisphenol A type liquid epoxy resin (manufactured by Japan Epoxy Resin Co., Ltd., trade name: Epicoat 828US, Mw = 370)
(2) Bisphenol F type liquid epoxy resin (manufactured by Japan Epoxy Resin Co., Ltd., trade name: Epicoat 806L, Mw = 370)
(3) Trifunctional glycidyldiamine type liquid epoxy resin (manufactured by Japan Epoxy Resin Co., Ltd., trade name: Epicoat 630, Mw = 300)
(4) Fluorene skeleton epoxy resin (manufactured by Osaka Gas Chemical Co., Ltd., trade name: ONCOAT EX1011, Mw = 486)
(5) Naphthalene skeleton liquid epoxy resin (manufactured by DIC, trade name: EPICLON HP-4032D, Mw = 304)
(6) Hexahydrophthalic acid skeleton liquid epoxy resin (manufactured by Nippon Kayaku Co., Ltd., trade name: AK-601, Mw = 284)
(7) Oxetane resin containing benzene skeleton (manufactured by Ube Industries, trade name: etanacol OXTP, Mw = 362.4)

[Curing agent (C)]
(1) Alicyclic skeleton acid anhydride (trade name: MH-700, manufactured by Shin Nippon Rika Co., Ltd.)
(2) Aromatic skeleton acid anhydride (manufactured by Sartomer Japan, trade name: SMA resin EF60)
(3) Polyalicyclic skeleton acid anhydride (manufactured by Shin Nippon Rika Co., Ltd., trade name: HNA-100)
(4) Terpene-based skeleton acid anhydride (manufactured by Japan Epoxy Resin, trade name: Epicure YH-306)
(5) Biphenyl skeleton phenolic resin (Madewa Kasei Co., Ltd., trade name: MEH-7851-S)
(6) Allyl group-containing skeletal phenol resin (manufactured by Japan Epoxy Resin, trade name: YLH-903)
(7) Melamine skeleton phenolic resin (manufactured by Gunei Chemical Industry Co., Ltd., trade name: PS-6492)

[Filler (D)]
(1) Spherical alumina (Denka Co., Ltd., trade name: DAM-10, average particle size 10 μm, thermal conductivity 36 W / m · K)
(2) Crushed alumina (Nippon Light Metal Co., Ltd., trade name: LS-242C, average particle size 2 μm, thermal conductivity 36 W / m · K)
(3) Synthetic magnesite (manufactured by Kamishima Chemical Co., Ltd., trade name: MSL, average particle size 6 μm, thermal conductivity 15 W / m · K)
(4) Crystalline silica (manufactured by Tatsumori Co., Ltd., trade name: Crystallite CMC-12, average particle size 5 μm, thermal conductivity 10 W / m · K)
(5) Amorphous silica (treated with a phenylsilane coupling agent, manufactured by Admatechs, trade name: SE2050 SPE, average particle size 0.5 μm, thermal conductivity 1.4 W / m · K)

[Dispersant]
(1) Acrylic dispersant (manufactured by Big Chemie Japan, trade name: Disperbyk-2070, pKa has a carboxyl group of 4)
(2) Polyether-based dispersant (manufactured by Enomoto Kasei Co., Ltd., trade name: ED151, pKa has 7 phosphate groups)

[Additive]
(1) Epoxysilane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KBE403)

[solvent]
(1) Methyl ethyl ketone

(Examples 1-14 and Comparative Examples 1-4)
Using a homodisper type stirrer, each raw material was blended in the proportions shown in Tables 1 to 3 below (blending unit is parts by weight) and kneaded to prepare an insulating material.

  The insulating material was applied to a release PET sheet having a thickness of 50 μm so as to have a thickness of 50 μm, and dried in an oven at 90 ° C. for 30 minutes to produce an insulating sheet on the PET sheet.

(Evaluation)
(1) Handling property A laminate sheet having a PET sheet and an insulating sheet formed on the PET sheet was cut into a size of 460 mm x 610 mm to obtain a test sample. Using the obtained test sample, the handling property when the insulating sheet was peeled from the PET sheet in an uncured state at room temperature (23 ° C.) was evaluated according to the following criteria.

[Handling criteria]
○: The insulating sheet is not deformed and can be easily peeled. Δ: Although the insulating sheet can be peeled, sheet elongation or breakage occurs. ×: The insulating sheet cannot be peeled.

(2) Thermal conductivity The thermal conductivity of the insulating sheet was measured using a thermal conductivity meter “quick thermal conductivity meter QTM-500” manufactured by Kyoto Electronics Industry Co., Ltd.

(3) Average thermal linear expansion coefficient The insulating sheet was cut into a size of 3 mm × 25 mm, cured in a 120 ° C. oven for 1 hour, and then cured in a 200 ° C. oven for 1 hour to prepare a test sample. After heating once from room temperature to 320 ° C. at a temperature rising rate of 10 ° C./min with a TMA apparatus (TMA / SS6000, manufactured by Seiko Instruments Inc.), the temperature rising rate from 0 ° C. to 300 ° C. is 10 ° C./min. The temperature at 25 to 100 ° C. when the temperature was raised at −100 ° C. The slope of the TMA straight line was measured, and the reciprocal of the obtained measured value was calculated as the average thermal linear expansion coefficient.

(4) Relative dielectric constant The insulating sheet was cut into a size of 30 mm × 30 mm, cured in a 120 ° C. oven for 1 hour, and then cured in a 200 ° C. oven for 1 hour to prepare a test sample. The relative permittivity of the test sample at a frequency of 1 GHz was measured using an impedance measuring instrument ("HP4291B" manufactured by Hewlett-Packard Company).

(5) Solder heat resistance test An insulating sheet is sandwiched between an aluminum plate having a thickness of 1.5 mm and an electrolytic copper foil having a thickness of 35 μm, and while maintaining a pressure of 4 MPa with a vacuum press machine at 120 ° C. for 1 hour, further at 200 ° C. The insulating sheet was press-cured for 1 hour to form a copper-clad laminate. The obtained copper-clad laminate was cut into a size of 50 mm × 60 mm to obtain a test sample. The obtained test sample was floated in a solder bath at 288 ° C. with the copper foil side facing down, and the time until the copper foil swelled or peeled off was measured and judged according to the following criteria.

[Criteria for solder heat resistance test]
◎: No swelling or peeling even after 10 minutes ○: Swelling or peeling occurs after 3 minutes and before 10 minutes △: Swelling or peeling after 1 minute and before 3 minutes X: Swelling or peeling occurs before 1 minute elapses

(6) Dielectric breakdown voltage The insulation sheet was cut out to a size of 100 mm × 100 mm to obtain a test sample. The obtained test sample was cured in an oven at 120 ° C. for 1 hour and further in an oven at 200 ° C. for 1 hour to obtain a cured product of an insulating sheet. An AC voltage was applied using a withstand voltage tester (MODEL7473, manufactured by EXTECH Electronics) so that the voltage increased at a rate of 1 kV / second between the cured products of the insulating sheet. The voltage at which the insulating sheet was broken was defined as the dielectric breakdown voltage.

(7) Transmission loss Ten insulating sheets were stacked to obtain a laminated body of insulating sheets. A copper foil having a thickness of 17 μm is disposed on the upper and lower surfaces of the obtained laminate, and the laminate of the insulating sheet is press-cured at 120 ° C. for 1 hour and further at 200 ° C. for 1 hour. A 55 mm test sample was prepared.

  The transmission loss of the obtained test sample was measured by a triplate line resonator method using a vector network analyzer, and evaluated according to the following evaluation criteria. The measurement conditions were a line width of 0.6 mm, an insulating layer distance between upper and lower ground conductors of 1.04 mm, a line length of 200 mm, a characteristic impedance of 50Ω, a frequency of 3 GHz, and a measurement temperature of 25 ° C.

[Evaluation criteria for transmission loss]
◯: Transmission loss is 10 dB / m or less ×: Transmission loss exceeds 10 dB / m

(8) Cooling cycle reliability A glass epoxy substrate having a circuit made of a copper foil having a thickness of 17 μm formed on one side was prepared. An insulating sheet was placed on the surface of the glass epoxy substrate on which the circuit was formed. Thereafter, an insulating sheet was laminated on one side of the glass epoxy substrate with a vacuum laminator (MVLP-500, manufactured by Meiki Seisakusho) under the condition of 80 ° C. Thereafter, the insulating sheet was cured at 120 ° C. for 1 hour and further at 200 ° C. for 1 hour to prepare a test sample.

  Using the obtained test sample, a 1000-cycle thermal cycle test was performed using a one-chamber type thermal cycle tester (WINTECH NT510, manufactured by ETACH) at -40 ° C for 20 minutes and 125 ° C for 20 minutes as one cycle. went. The presence or absence of cracks on the surface of the cured product of the test sample after the test was observed with an optical microscope (TRANSFORMER-XN, manufactured by Nikon). Moreover, the presence or absence of peeling on the surface of the cured product of the test sample after the test was observed with an ultrasonic flaw detector (mi-scope hyper, manufactured by Hitachi Construction Machinery Finetech Co., Ltd.). The number of specimens of the test sample in which cracks or peeling occurred in 10 specimens of the test sample was counted, and the thermal cycle reliability was evaluated according to the following evaluation criteria.

[Evaluation criteria for reliability of thermal cycle]
◯: 2 or less test samples out of 10 specimens in which crack or peeling occurred Δ: 3 to 4 specimens in 10 specimens in which crack or peeling occurred ×: 10 specimens in which crack or peeling occurred Among these, the results are shown in Tables 1 to 3 below.

DESCRIPTION OF SYMBOLS 1 ... Laminated structure 2 ... Board | substrate 2a ... Via hole 2b ... Conductor layer 2c ... Upper surface 2d ... Lower surface 3, 4 ... Insulating layer 3a ... Upper surface 4a ... Lower surface 5, 7, 8 ... Conductive layer 6 ... Insulating layer 11 ... Laminated structure DESCRIPTION OF SYMBOLS 12 ... Board | substrate 12a ... Upper surface 12b ... Conductor layer 12c ... Recessed part 13-15 ... Insulating layer 13a, 14a ... Upper surface 13b, 14b ... Conductive layer 13c, 14c ... Recessed part

Claims (16)

A polymer having a diphenylene sulfone group;
A curable compound having an epoxy group or an oxetane group;
A curing agent;
An insulating sheet containing a filler.   The insulating sheet according to claim 1, wherein the polymer is soluble in an organic solvent.   When the insulating sheet is cured, the cured product has a thermal conductivity of 0.5 W / m · K or more, the average thermal linear expansion coefficient at 25 to 100 ° C. of the cured product is 20 ppm / ° C. or less, and the cured product at 1 GHz. The insulating sheet according to claim 1 or 2, wherein the relative dielectric constant is 5 or less.   The said hardening | curing agent is an acid anhydride which has an aromatic skeleton or an alicyclic skeleton, the water additive of this acid anhydride, or the modified product of this acid anhydride, any one of Claims 1-3. The insulating sheet according to item.   Fats obtained by the addition reaction of an acid anhydride having a polyalicyclic skeleton, a water additive of the acid anhydride or a modified product of the acid anhydride, or a terpene compound and maleic anhydride. The insulating sheet according to claim 4, which is an acid anhydride having a cyclic skeleton, a water additive of the acid anhydride, or a modified product of the acid anhydride. The insulating sheet according to claim 5, wherein the curing agent is an acid anhydride represented by any one of the following formulas (1) to (4).

In said formula (4), R1 and R2 show hydrogen, a C1-C5 alkyl group, or a hydroxyl group, respectively.   The insulating sheet according to claim 4, wherein the curing agent is a phenol resin having a melamine skeleton or a triazine skeleton, or a phenol resin having an allyl group.   The filler according to any one of claims 1 to 7, wherein the filler is at least one selected from the group consisting of silica, alumina, boron nitride, aluminum nitride, silicon nitride, silicon carbide, zinc oxide, magnesite, and magnesium oxide. The insulating sheet according to item.   The insulating sheet according to any one of claims 1 to 8, wherein the filler content is in the range of 30 to 90% by volume.   The insulating sheet according to claim 1, wherein the filler is spherical.   The insulating sheet according to claim 1, wherein the filler is treated with a coupling agent. A substrate having a first conductor layer on at least one surface and having a through hole or a recess on the one surface;
An insulating layer laminated on the one surface or both surfaces of the substrate;
A second conductor layer or a circuit board laminated on a surface opposite to the surface on which the substrate of the insulating layer is laminated,
The laminated structure in which the said insulating layer is formed by hardening the insulating sheet of any one of Claims 1-11.   The laminated structure according to claim 12, wherein at least one of the first conductor layer and the second conductor layer is a wiring circuit.   The multilayer structure according to claim 12 or 13, which is a multilayer circuit board having two or more conductor layers.   The multilayer structure according to any one of claims 12 to 14, which is a multilayer circuit board used for a chip size package. 12. The device according to claim 1, wherein the first conductor layer is provided on at least one surface, and the one surface or both surfaces of the substrate having a through hole or a concave portion on the one surface are provided. Laminating the insulating sheet so that a part of the insulating sheet is filled in the through-hole or the recess;
Laminating a conductor layer or a circuit board on a surface of the laminated insulating sheet opposite to the surface on which the substrate is disposed;
And a step of curing the insulating sheet.

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