JP5830940B2 - Prepreg, metal-clad laminate and printed wiring board - Google Patents

Description

  The present invention relates to a prepreg, and a metal-clad laminate and a printed wiring board using the prepreg.

In recent years, in the field of electronic equipment such as semiconductors, a trend of shifting from conventional surface mounting to area mounting has progressed due to advances in high-density mounting technology, and new packages such as BGA (Ball Grid Allay) and CSP (chip size package) have been developed. Appearance is increasing. For this reason, interposer substrates have attracted more attention than ever before, and there is an increasing demand for glass epoxy substrates with high heat resistance and low thermal expansion.
Under such circumstances, in general, inorganic fillers, particularly spherical fused silica, are frequently used to reduce the thermal expansion coefficient. In addition, with increasing environmental problems, resin systems that do not contain halides are required, and in combination with inorganic hydroxides such as aluminum hydroxide as flame retardants (for example, Patent Documents 1 to 3).

JP 2010-31263 A JP 2009-74036 A JP 2009-155398 A

  In the case of a prepreg comprising a glass filler such as silica for the purpose of reducing the thermal expansion coefficient and further using aluminum hydroxide for the purpose of ensuring flame retardancy and improving processability, When producing a material, streaks composed of resin flow are generated at the end of the base due to non-uniformity of the fluidity of the glass filler and aluminum hydroxide, and the base end deteriorates. However, there are problems that the characteristics are deteriorated compared to the central part, and the drilling workability of the base material is lowered.

  Therefore, in the present invention, although glass hydroxide such as silica is used together with aluminum hydroxide for the purpose of ensuring flame retardancy and improving workability, the glass filler is uniformly dispersed, and the resin flow A prepreg capable of obtaining a metal-clad laminate having excellent properties, excellent circuit formability, excellent drillability, and low thermal expansion, and a metal-clad laminate and a printed wiring board using the prepreg The purpose is to provide.

（ただし、Ｒはフェノール性水酸基を２個以上有しかつ分子量が１８０以上である有機基である。）
［４］前記化学式（１）におけるＲで示される有機基が、下記化学式（２）、（３）、（４）、（５）、及び（６）から選択される構造の１種又は２種以上を有し、フェノール性水酸基を２個以上有する［３］に記載のプリプレグ。
（化学式（２）〜（６）における＊は、化学式（１）のリン原子に直接結合する部位であることを示す。）

（化学式（５）におけるＲ¹は、水素原子又は炭素数１〜３のアルキル基であり、Ｒ²は、炭素数１〜４のアルキル基である。ｎは芳香環におけるＯＲ²基の数であり、１〜３のいずれかである。また、Ｒ^Aは、フェノール性水酸基を２個以上有する有機基である。）

（化学式（６）におけるＲ¹は、水素原子又は炭素数１〜３のアルキル基であり、Ｒ²は、炭素数１〜４のアルキル基である。ｎは芳香環におけるＯＲ²基の数であり、１〜３のいずれかである。また、Ｒ^Bは、フェノール性水酸基を２個以上有する有機基である。）
［５］化学式（１）におけるＲで示される有機基が、下記化学式（７）、（８）及び（９）から選択される構造の１種又は２種以上を有し、フェノール性水酸基を２個以上有する請求項４に記載のエポキシ樹脂組成物。
（化学式（７）〜（９）における＊は、化学式（１）のリン原子に直接結合する部位であることを示す。）

［６］［１］〜［５］のいずれかに記載のプリプレグを一枚又は複数枚重ね、その両面又は片面に金属箔を配し、加熱加圧して成る金属張積層板。
［７］［６］に記載の金属張積層板の金属層を配線加工して成る印刷配線板。 The present invention provides the following [1] to [7].
[1] In a prepreg formed by impregnating a resin composition into a substrate, the resin composition contains aluminum hydroxide having an average particle diameter of 2.5 to 4.5 μm, an average particle diameter of 1.0 to 3.0 μm, A glass filler having a specific gravity of 2.3 to 2.6 g / cm ³ and a SiO ₂ content of 50 to 65 mass%, and the aluminum hydroxide and the glass filler in the total solid content of the resin composition The prepreg whose sum total of the compounding quantity is 30-50 mass%.
[2] The prepreg according to [1], wherein the resin composition has a non-halogenated epoxy compound having at least two epoxy groups in one molecule.
[3] The prepreg according to [1] or [2], wherein the resin composition includes a phosphorus-containing curing agent represented by the following chemical formula (1).

(However, R is an organic group having two or more phenolic hydroxyl groups and a molecular weight of 180 or more.)
[4] One or two kinds of structures in which the organic group represented by R in the chemical formula (1) is selected from the following chemical formulas (2), (3), (4), (5), and (6) The prepreg according to [3], having the above and having two or more phenolic hydroxyl groups.
(* In chemical formulas (2) to (6) indicates a site directly bonded to the phosphorus atom of chemical formula (1).)

(R ¹ in chemical formula (5) is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and R ² is an alkyl group having 1 to 4 carbon atoms. N is the number of OR ² groups in the aromatic ring. Yes, and any one of 1 to 3. Further, R ^A is an organic group having two or more phenolic hydroxyl groups.

(R ¹ in chemical formula (6) is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and R ² is an alkyl group having 1 to 4 carbon atoms. N is the number of OR ² groups in the aromatic ring. There are either 1-3. also, R ^B is an organic group having two or more phenolic hydroxyl groups.)
[5] The organic group represented by R in the chemical formula (1) has one or more types of structures selected from the following chemical formulas (7), (8) and (9), and has 2 phenolic hydroxyl groups. The epoxy resin composition according to claim 4 having at least one.
(* In chemical formulas (7) to (9) indicates a site directly bonded to the phosphorus atom of chemical formula (1).)

[6] A metal-clad laminate obtained by stacking one or more prepregs according to any one of [1] to [5], placing metal foil on both sides or one side, and heating and pressing.
[7] A printed wiring board obtained by wiring a metal layer of the metal-clad laminate according to [6].

  According to the present invention, despite the combined use of glass filler and aluminum hydroxide, the glass filler is uniformly dispersed, and a metal-clad laminate having excellent drill workability and a low thermal expansion coefficient is obtained. It is possible to provide a prepreg that can be used, and a metal needle laminate and a printed wiring board using the prepreg.

[Prepreg]
The prepreg used in the present invention is obtained by impregnating a base material with a specific resin composition.
<Base material>
The substrate is not particularly limited as long as it is used when producing a metal foil-clad laminate or a multilayer printed wiring board, but a fiber substrate such as a woven fabric or a nonwoven fabric is usually used. Examples of the fiber base material include glass, alumina, boron, silica-alumina glass, silica glass, tyrano, silicon carbide, silicon nitride, zirconia, and other inorganic fibers, aramid, polyetheretherketone, polyetherimide, polyethersulfone Further, there are organic fibers such as carbon and cellulose, and mixed papers thereof, and glass fiber woven fabrics are particularly preferably used. As the base material used for the prepreg, a glass woven fabric of 10 μm to 200 μm is particularly preferably used.

<Resin composition>
The resin composition includes aluminum hydroxide having an average particle diameter of 2.5 to 4.5 μm, an average particle diameter of 1.0 to 3.0 μm, a specific gravity of 2.3 to 2.6 g / cm ³ and a SiO ₂ ratio of 50 to 50. 65 mass% glass filler is included, and the total of the compounding quantity of the said aluminum hydroxide and the said glass filler in solid content total amount is 30-50 mass%.
Next, each component of the resin composition will be described.

≪Aluminum hydroxide≫
The resin composition contains aluminum hydroxide. Aluminum hydroxide has more hydration water than magnesium hydroxide and other inorganic hydrates, has good flame retardancy, and is relatively stable against acids and alkalis. It is suitable for. In consideration of resin flow, the average particle size needs to be 2.5 to 4.5 μm. If it is less than 2.5 μm, the chemical resistance decreases due to an increase in specific surface area. On the other hand, if it exceeds 4.5 μm, the sedimentation in the varnish is accelerated, which is not preferable.
The average particle diameter can be measured using water as a dispersion using, for example, a laser scattering particle size distribution meter MT3000 manufactured by Nikkiso Co., Ltd.

≪Glass filler≫
As the glass filler, those content of SiO ₂ is 50 to 65 mass% is used. If the content of SiO ₂ is less than 50%, the effect of reducing thermal expansion becomes small, and if it exceeds 65%, the workability of a drill or the like deteriorates, which is not preferable.
Components other than SiO ₂ in the glass filler include Al ₂ O ₃ , K ₂ O, Na ₂ O, CaO, Fe ₂ O ₃ , B ₂ O ₃ , SrO, MgO, MnO, GeO ₂ and P ₂ O _3. , P ₂ O ₅ , Y ₂ O ₅ , ZrO _{2 and the} like can be considered, but are not limited thereto.
The glass filler has an average particle size of 1.0Myuemu～3.0Myuemu, and specific gravity of ^{2.3g / cm 3 ~2.5g / cm 3} . A prepreg having a glass filler outside this range has a large decrease in resin fluidity, and agglomeration occurs, resulting in poor circuit moldability.
As a thermal expansion characteristic, it is preferable that the thermal expansion coefficient below Tg is 40 ppm / ° C. The melting temperature of the glass filler is preferably 1700 ° C. or higher because stirring is performed uniformly and the quality is stabilized.

≪Aluminum hydroxide and glass filler≫
The sum total of the compounding quantity of the said aluminum hydroxide and the said glass filler in the solid content total amount of a resin composition is 30-50 mass%. If this total is less than 30% by mass, low thermal expansion characteristics for ensuring connection reliability cannot be obtained, and if it exceeds 50% by mass, the outer layer peel strength decreases, the drill wear increases, and the circuit formability. Decrease is observed.
The use ratio of aluminum hydroxide and glass filler can be arbitrarily set, but is preferably 4: 6 to 6: 4. Within this range, heat resistance is high, drill wear is small, and fluidity is excellent.

≪Resin≫
The resin in the resin composition is not particularly limited, but is preferably a thermosetting resin, and may be a thermoplastic resin having high heat resistance. As the resin, for example, an epoxy resin, a polyimide resin, a triazine resin, a melamine resin, a phenol resin, or the like is used. Two or more kinds of these resins may be used in combination, and if necessary, various curing agents and curing accelerators described later may be blended in the resin, and these may be blended as a solvent or a solution.

  As the resin, it is preferable to use an epoxy resin having at least two epoxy groups in one molecule. In particular, it is preferable to include a non-halogenated epoxy compound having at least two epoxy groups in one molecule and not containing a halogen atom. This prevents the generation of toxic gas due to the halogen element during combustion due to a fire or the like, and also prevents the heat resistance and reliability from being degraded due to decomposition of the halogen element during heating. Examples of the non-halogenated epoxy compound include bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol S type epoxy resin, biphenyl type epoxy resin, alicyclic epoxy resin, phenol novolac epoxy resin, bisphenol A novolac epoxy resin, and cresol. Examples thereof include, but are not limited to, novolak epoxy resins, diglycidyl etherified products of polyfunctional phenols, diglycidyl etherified products of polyfunctional alcohols, and hydrogenated products thereof. These non-halogenated epoxy compounds may be used alone or in combination. Among these, in consideration of heat resistance and a high glass transition temperature, novolac type epoxy resins such as phenol novolac epoxy resin, bisphenol A novolac epoxy resin, and cresol novolac epoxy resin are preferable. In consideration of electrical characteristics, it is desirable to use an epoxy resin such as tetramethylbiphenyl type epoxy, phenol aralkyl epoxy, naphthalene aralkyl epoxy, or dicyclopentadiene type epoxy.

≪Curing agent≫
As the curing agent, various conventionally known ones can be used. For example, when an epoxy resin is used as the resin, amine compounds such as dicyandiamide, diaminodiphenylmethane, and diaminodiphenylsulfone, phthalic anhydride, pyromellitic anhydride And polyfunctional phenolic compounds such as phenol novolac resins and cresol novolac resins. Several kinds of these curing agents can be used in combination.
(Phosphorus-containing curing agent)
A phosphorus-containing curing agent can also be used. As this phosphorus containing hardening | curing agent, the phosphorus containing hardening | curing agent shown by following Chemical formula (1) can be used conveniently.

(However, R is an organic group having two or more phenolic hydroxyl groups and a molecular weight of 180 or more.)

Molded articles such as prepregs and metal foil-clad laminates using this phosphorus-containing curing agent have flame retardancy and also have very good characteristics such as heat resistance, electrical characteristics, and water resistance.
In the above chemical formula (1), R is preferably an organic group having two or more phenolic hydroxyl groups and a molecular weight of 180 or more, more preferably an organic group of 190 or more. When the molecular weight is 180 or more, the solvent solubility of the phosphorus curing agent is improved and the handleability is improved. Examples of the phosphorus-containing curing agent include HCA-HQ (10- (2,5-dihydroxyphenyl) -10H-9-oxa-10-phosphaphenanthrene-10-oxide), HCA-NQ (10- (2, 7-dihydroxynaphthyl) -10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide) and the like.
Since these have low solubility in a solvent, they are generally blended after a pre-reaction. Furthermore, it is preferable that the structure of the organic group (R) has a structure represented by the chemical formula (— (CH ₂ ) —). When it has a structure represented by the chemical formula (— (CH ₂ ) —), the heat resistance is improved and the handleability is improved.

From the viewpoint of flame retardancy, the phosphorus content in the resin composition is preferably 0.8 to 5.0 mass% of the total solid content of the resin composition, and preferably 1.0 to 2.5 mass%. It is more preferable that When the phosphorus content is less than 0.8% by mass of the total solid content of the resin composition, it is difficult to obtain stable flame retardancy, and when it exceeds 5.0% by mass, the properties of the cured product are deteriorated. .
Here, the phosphorus content is the content of phosphorus atoms in the resin composition. For example, if a substance having a molecular weight of 620 has one phosphorus atom and contains 50% by mass of this substance, 2. The phosphorus component content is 5 mass% (since the atomic weight of phosphorus atoms is about 31, 31/620 × 0.5 = 0.0250).

(Organic group represented by R in chemical formula (1))
The organic group represented by R in the chemical formula (1) has one or more types of structures selected from the following chemical formulas (2), (3), (4), (5), and (6). And having two or more phenolic hydroxyl groups. * In chemical formulas (2) to (6) indicates a site directly bonded to the phosphorus atom of chemical formula (1).

（化学式（５）におけるＲ¹は、水素原子又は炭素数１〜３のアルキル基であり、Ｒ²は、炭素数１〜４のアルキル基である。ｎは芳香環におけるＯＲ²基の数であり、１〜３のいずれかである。また、Ｒ^Aは、フェノール性水酸基を２個以上有する有機基である。）

(R ¹ in chemical formula (5) is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and R ² is an alkyl group having 1 to 4 carbon atoms. N is the number of OR ² groups in the aromatic ring. Yes, and any one of 1 to 3. Further, R ^A is an organic group having two or more phenolic hydroxyl groups.

（化学式（６）におけるＲ¹は、水素原子又は炭素数１〜３のアルキル基であり、Ｒ²は、炭素数１〜４のアルキル基である。ｎは芳香環におけるＯＲ²基の数であり、１〜３のいずれかである。また、Ｒ^Bは、フェノール性水酸基を２個以上有する有機基である。）

(R ¹ in chemical formula (6) is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and R ² is an alkyl group having 1 to 4 carbon atoms. N is the number of OR ² groups in the aromatic ring. There are either 1-3. also, R ^B is an organic group having two or more phenolic hydroxyl groups.)

  In addition, the organic group represented by R in the chemical formula (1) has one or more types of structures selected from the following chemical formulas (7), (8) and (9), and includes two phenolic hydroxyl groups. It can be set as the organic group which has the above. * In chemical formulas (7) to (9) indicates a site directly bonded to the phosphorus atom of chemical formula (1).

When it has a structure shown by the said Chemical formula (2), the heat resistance of the epoxy resin composition containing this phosphorus containing hardening | curing agent improves. Moreover, since the solubility of the phosphorus containing hardening | curing agent to the solvent which is a reaction system improves, a handleability improves.
When having the structure represented by the chemical formula (3), the reactivity with the resin is improved.
When it has a structure shown by the said Chemical formula (4), the heat resistance of the epoxy resin composition containing this phosphorus containing hardening | curing agent improves.
When it has a structure shown by the said Chemical formula (5)-(9), the heat resistance of the epoxy resin composition containing this phosphorus containing hardening | curing agent improves.
In particular, since the phosphorus-containing curing agent having the structure represented by the chemical formula (2) has a low viscosity, it is excellent in handleability and can improve productivity.

(Phosphorus-containing curing agent 1)
For example, the phosphorus-containing curing agent can be a resin having a structural unit A represented by the following chemical formula (10) and a structural unit B represented by the chemical formula (11).

That is, this resin may have a unit in which a plurality of structural units A are continuous, or may have a unit in which a plurality of structural units B are continuous. It may have a unit formed by alternately connecting B and may have a structure in which the three party units are mixed.
When the phenol resin having the structural unit described above is used as a phosphorus-containing curing agent, the heat resistance of the epoxy resin composition is improved.

(Phosphorus-containing curing agent 2)
(A) The phosphorus-containing curing agent can be a resin having a structural unit C represented by the following chemical formula (12) and a structural unit D represented by the chemical formula (13).

That is, this resin may have a unit in which a plurality of structural units C are continuous, or may have a unit in which a plurality of structural units D are continuous. It may have a unit formed by alternately connecting D and may have a structure in which the three party units are mixed.
When the phenol resin having the structural unit described above is used as a phosphorus-containing curing agent, the heat resistance of the epoxy resin composition is improved.

(Phosphorus-containing curing agent 3)
(A) The phosphorus-containing curing agent may be a resin having a structural unit E represented by the following chemical formula (14) and a structural unit F represented by the chemical formula (15).

That is, this resin may have a unit in which a plurality of structural units E are continuous, or may have a unit in which a plurality of structural units F are continuous. It may have a unit formed by alternately connecting with F, and may have a structure in which the three party units are mixed.
When the phenol resin having the structural unit described above is used as a phosphorus-containing curing agent, the heat resistance of the epoxy resin composition is improved.

(Method for producing phosphorus-containing curing agent)
The phosphorus-containing curing agent represented by the chemical formula (1) is obtained by reacting a compound having a phenolic hydroxyl group with the phosphorus compound represented by the chemical formula (16). In some cases, p-anisaldehyde may be added.

化学式（１０）中のＸは、Ｈ原子又はハロゲン原子である。

X in the chemical formula (10) is an H atom or a halogen atom.

  As a compound having a phenolic hydroxyl group that can be used in the production of a phosphorus-containing curing agent, a compound having two or more phenolic hydroxyl groups in one molecule is preferable, and phenol, cresol, xylenol, resorcin, catechol, bisphenol A, Obtained by condensing or co-condensing phenols such as bisphenol F or naphthols such as α-naphthol, β-naphthol, dihydroxynaphthalene and the like and aldehydes such as formaldehyde, acetaldehyde, propionaldehyde, benzaldehyde, salicylaldehyde in the presence of an acidic catalyst. Resins (novolaks), polyparavinylphenol resins, phenol / aralkyl resins having a xylylene group synthesized from phenols and dimethoxyparaxylene, alone or in combination of two or more May be used.

≪Curing accelerator≫
The type and blending amount of the curing accelerator are not particularly limited, and for example, imidazole compounds, organophosphorus compounds, secondary amines, tertiary amines, quaternary ammonium salts, etc. are used, and two or more types are used. May be used in combination. Although the compounding quantity of a hardening accelerator is not restrict | limited in particular, 0.01-10.0 mass parts is desirable with respect to 100 mass parts of resin which is a main material.

≪Coupling agent≫
A coupling agent may be added to the resin composition. By adding a coupling agent, the dispersibility of the inorganic filler can be improved, and a material excellent in chemical resistance and peel strength can be obtained.
The coupling agent is generally used in thermosetting resin compositions and is not particularly limited. For example, a silane compound having primary and / or secondary and / or tertiary amino groups, epoxy silane, Examples include various silane compounds such as mercaptosilane, alkyl silane, ureido silane, and vinyl silane, titanium compounds, aluminum chelates, and aluminum / zirconium compounds.

<Method for producing prepreg>
The method for impregnating the base material with the resin composition is not particularly limited. For example, a method of impregnating a substrate with a resin composition varnish by a wet method or a dry method, a method of applying a resin composition to a substrate, and the like can be mentioned. For example, a prepreg can be obtained by applying and impregnating the thermosetting resin composition to a glass cloth or a glass nonwoven fabric, and heating or drying continuously or discontinuously to form a B stage.

[Metal-clad laminates and printed wiring boards]
A metal foil-clad laminate is obtained by laminating a metal foil on one or both sides of the prepreg or a laminate obtained by laminating a plurality of the prepregs and then subjecting the laminate to heating and pressing. The heating temperature is preferably 170 ° C to 240 ° C, and the pressure is preferably 1 to 8 MPa.
Further, the metal layer of the metal-clad laminate can be processed by wiring (circuit processing) to obtain a printed wiring board (circuit board).
The metal foil is generally 8 μm to 80 μm, and the thickness of the laminate is generally 20 μm to 200 μm.

  Further, by laminating the metal foil-clad laminate or the circuit pattern-formed inner layer substrate with the resin surface facing each other through the prepreg, thermoforming, and further forming the outer layer circuit, A multilayer printed wiring board can also be obtained.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples without departing from the technical idea of the present invention.
[Production Example 1 (Glass Filler A)]
After an inorganic substance containing SiO ₂ : 53 mass%, Al ₂ O ₃ : 14 mass%, CaO: 20 mass%, MgO: 3 mass%, B ₂ O ₃ : 10 mass% is dissolved at high temperature and cooled, Crushing and classification with a cyclone classifier were carried out to produce a glass filler (crushed inorganic filler) A having an average particle size of 2.0 μm and a specific gravity of 2.5 g / cm ³ .
The average particle diameter was measured using water as a dispersion using a laser scattering particle size distribution analyzer MT3000 manufactured by Nikkiso Co., Ltd.

[Production Example 2 (Glass filler B)]
An inorganic substance containing SiO ₂ : 62% by mass, Al ₂ O ₃ : 18% by mass, CaO: 8% by mass, B ₂ O ₃ : 12% by mass is dissolved at high temperature and cooled, and then pulverized with a ball mill, with a cyclone classifier. Classification was performed to prepare a glass filler (crushed inorganic filler) B having an average particle size of 2.0 μm and a specific gravity of 2.4 g / cm ³ .

[Synthesis Example 1 (Phosphorus Resin (Curing Agent) 1)]
A method for synthesizing the phosphorus resin (curing agent) 1 will be described below.
The melt viscosity at 180 ° C. was measured according to ASTM D4287, and the softening point was measured according to JIS K7234.
In a flask equipped with a thermometer, a condenser tube, a fractionating tube, a nitrogen gas inlet tube, and a stirrer, 192.4 g (1.85 mol) of phenol novolac resin, 68.0 g (0.50 mol) of p-anisaldehyde and 9 , 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (hereinafter abbreviated as HCA) 108.0 g (0.50 mol), heated to 180 ° C. and reacted at 180 ° C. for 8 hours. .
Next, water is removed under reduced pressure by heating, and a phenol resin (phosphorous resin (curing agent)) 1 having a structural unit represented by the following chemical formula (10) and a structural unit represented by the following chemical formula (11) is obtained. 355 g was obtained. The obtained phenol resin (phosphorus resin (curing agent)) 1 has a softening point of 125 ° C. (B & R method), a melt viscosity (measurement method: ICI viscometer method, measurement temperature: 180 ° C.) of 13 dPa · s, hydroxyl group equivalent Was 190 g / eq, and the phosphorus content was 4.2 mass%.

[Synthesis Example 2 (Phosphorus resin (curing agent) 2)]
In the synthesis example 1, the structural unit represented by the following chemical formula (12) and the following structure are the same as those in the synthesis example 1 except that the phenol novolac resin is changed to 330.4 g (2.80 mol) instead of the phenol novolac resin. 490 g of phenol resin (phosphorus resin (curing agent)) 2 having a structural unit represented by the chemical formula (13) was obtained. The softening point of this phenol resin (phosphorus resin (curing agent)) 2 is 139 ° C. (B & R method), the melt viscosity (measurement method: ICI viscometer method, measurement temperature: 180 ° C.) is 65 dPa · s, and the hydroxyl group equivalent is 232 g. / Eq, phosphorus content was 3.1% by mass.

[Synthesis Example 3 (Phosphorus resin (curing agent) 3)]
In Synthesis Example 1, the structural unit represented by the following chemical formula (14) and the following chemical formula were used in the same manner as in Synthesis Example 1 except that the phenol aralkyl resin was changed to 392.9 g (2.35 mol) instead of the phenol novolak resin. 550 g of phenol resin (phosphorus resin (curing agent)) 3 having the structural unit represented by (15) was obtained. The obtained phenol resin (phosphorus resin (curing agent)) 3 has a softening point of 102 ° C. (B & R method) and a melt viscosity (measurement method: ICI viscometer method, measurement temperature: 150 ° C.) of 2.5 dPa · s, The hydroxyl equivalent was 232 g / eq, and the rinn content was 2.7% by mass.

[Example 1]
In a glass flask equipped with a stirrer, a condenser, and a thermometer, 25.0 parts by mass of a phenol novolac type epoxy resin (epoxy equivalent: 178, manufactured by Mitsubishi Chemical Corporation, Epicoat 154) as an epoxy resin, and a brominated epoxy resin (Epoxy equivalent: 475, manufactured by Mitsubishi Chemical Corporation, Epicoat 5046) 75.0 parts by mass was added, and phenol novolak resin (Hitachi Chemical Industry Co., Ltd., HP-1100) 31.3 parts by mass as a curing agent (phenol resin). 30.0 parts by weight of aluminum hydroxide (manufactured by Sumitomo Chemical Co., Ltd., CL-303, average particle size 4.1 μm) is added as filler (1), and glass filler A30 is used as filler (2). 0.0 part by mass and 2E4MZ (manufactured by Shikoku Kasei Co., Ltd.) 0.1 part by mass as a curing accelerator Things and dissolved in MEK (methyl ethyl ketone) with a varnish temperature 40 ° C., diluted, stirring is carried out for 1 hour at room temperature, was adjusted with MEK to a solid content of 60 mass% of the resin composition varnish.
This varnish was impregnated into a glass cloth (style 2116, E glass) having a thickness of about 100 μm and dried at 150 ° C. for 5 minutes to obtain a prepreg having a resin content of 50% by mass. Sixteen prepregs were stacked, 12 μm copper foils were stacked on both sides thereof, and heated and pressed under 170 ° C. for 90 minutes and 4.0 MPa pressing conditions to prepare a copper clad laminate having a thickness of about 1.6 mm.

[Example 2]
As epoxy resin, phenol novolac type epoxy resin (epoxy equivalent: 178, manufactured by Mitsubishi Chemical Corporation, Epicoat 154) 15.0 parts by mass, tetrakishydroxyphenylmethane type epoxy resin (epoxy equivalent: 200, manufactured by Mitsubishi Chemical Corporation, Epicoat) 1031S) 3.0 parts by mass and brominated epoxy resin (epoxy equivalent: 475, manufactured by Mitsubishi Chemical Corporation, Epicoat 5046) 82.0 parts by mass, phenol novolac resin (Hitachi Chemical Industries) as a curing agent (phenol resin) As a filler (2), 28.6 parts by mass, HP-1100), 43.0 parts by mass of aluminum hydroxide (Sumitomo Chemical Co., Ltd., CL-303) are used as the filler (1). The same as in Example 1 except that 43.0 parts by mass of glass filler A was used. To give a leg and a copper-clad laminate.

[Example 3]
100.0 parts by mass of a phenol novolac type epoxy resin (epoxy equivalent: 178, manufactured by Mitsubishi Chemical Corporation, Epicoat 154) is used as an epoxy resin, and a phenol novolak resin (manufactured by Hitachi Chemical Co., Ltd., HP) is used as a curing agent (phenol resin). −1100) 59.0 parts by mass, 79.0 parts by mass of aluminum hydroxide (manufactured by Sumitomo Chemical Co., Ltd., CL-303) as filler (1), and glass filler A79.0 as filler (2). A prepreg and a copper clad laminate were obtained in the same manner as in Example 1 except that the parts by mass were used.

[Example 4]
As epoxy resin, phenol novolac type epoxy resin (epoxy equivalent: 178, manufactured by Mitsubishi Chemical Corporation, Epicoat 154) 80.0 parts by mass, and tetrakishydroxyphenylmethane type epoxy resin (epoxy equivalent: 200, manufactured by Mitsubishi Chemical Corporation, Epicoat) 1031S) 20.0 parts by mass, 53.0 parts by mass of phenol novolac resin (manufactured by Hitachi Chemical Co., Ltd., HP-1100) as a curing agent (phenol resin), and phosphorus phenol as a phosphorus resin (curing agent) 33.5 parts by mass of resin (Dow Chemical Company, XZ-92741) and 60.0 parts by mass of aluminum hydroxide (manufactured by Sumitomo Chemical Co., Ltd., CL-303) as filler (1) and filler (2 ) As in Example 1 except that 60.0 parts by mass of glass filler B is used. It was obtained a prepreg and a copper-clad laminate.

[Example 5]
A prepreg and a copper clad laminate were obtained in the same manner as in Example 4 except that 40.0 parts by mass of glass filler B was used as the filler (2).

[Example 6]
As epoxy resins, phenol novolac type epoxy resin (epoxy equivalent: 178, manufactured by Mitsubishi Chemical Corporation, Epicoat 154) 80.0 parts by mass, and bisphenol A novolac type epoxy resin (epoxy equivalent: 210, manufactured by Mitsubishi Chemical Corporation, Epicoat) 157) Using 20.0 parts by mass, omitting the curing agent (phenolic resin), using 103.5 parts by mass of the resin synthesized in Synthesis Example 1 as the phosphorus resin (curing agent), and using the filler (1) Prepreg and copper-clad as in Example 1 except that 45.0 parts by mass of aluminum hydroxide (Sumitomo Chemical Co., Ltd., CL-303) and 45.0 parts by mass of glass filler A as filler (2) were used. A laminate was obtained.

[Example 7]
As epoxy resins, 50.0 parts by mass of phenol novolac type epoxy resin (epoxy equivalent: 178, manufactured by Mitsubishi Chemical Corporation, Epicoat 154) and bisphenol A novolac type epoxy resin (epoxy equivalent: 210, manufactured by Mitsubishi Chemical Corporation, Epicoat) 157) Using 50.0 parts by mass, omitting the curing agent (phenolic resin), using 119.0 parts by mass of the resin synthesized in Synthesis Example 2 as the phosphorus resin (curing agent), and using the filler (1) Prepreg and copper-clad as in Example 1 except that 60.0 parts by mass of aluminum hydroxide (CL-303, manufactured by Sumitomo Chemical Co., Ltd.) and 90.0 parts by mass of glass filler A as filler (2) were used. A laminate was obtained.

[Example 8]
As epoxy resins, phenol novolac type epoxy resin (epoxy equivalent: 178, manufactured by Mitsubishi Chemical Corporation, Epicoat 154) 30.0 parts by mass, and bisphenol A novolac type epoxy resin (epoxy equivalent: 210, manufactured by Mitsubishi Chemical Corporation, Epicoat) 157) Using 70.0 parts by mass, omitting the curing agent (phenolic resin), using 100.0 parts by mass of the resin synthesized in Synthesis Example 3 as a phosphorus resin (curing agent), and using the filler (1) Prepreg and copper-clad as in Example 1 except that 120.0 parts by mass of aluminum hydroxide (CL-303, manufactured by Sumitomo Chemical Co., Ltd.) and 80.0 parts by mass of glass filler B as filler (2) were used. A laminate was obtained.

[Comparative Example 1]
Example 1 except that 30 parts by mass of silica (manufactured by Admatechs Co., Ltd., SO-25R, amorphous silica powder, average particle size 0.5 μm) was used as the filler (3) instead of the filler (2). Similarly, a prepreg and a copper clad laminate were obtained.

[Comparative Example 2]
Example 2 except that 43 parts by mass of silica (manufactured by Admatechs, SO-25R, amorphous silica powder, average particle size 0.5 μm) was used as the filler (3) in place of the filler (1). Similarly, a prepreg and a copper clad laminate were obtained.

[Comparative Example 3]
A prepreg and a copper clad laminate were obtained in the same manner as in Example 2 except that the filler (1) and the filler (2) were not added.
Tables 1 and 2 summarize the main components used in Examples 1-8 and Comparative Examples 1-3.

[Evaluation]
The following evaluations were performed using samples obtained by etching the entire surface of the outer layer copper foil of the copper clad laminate produced in Examples 1 to 8 and Comparative Examples 1 to 3. The results are shown in Table 3.
(1) Appearance evaluation A sample in which no streak consisting of resin flow was generated on the surface of the sample was defined as "good". In addition, a streak was defined as a streak, and the occurrence location was identified.
(2) Thermal expansion coefficient About the said sample, the thermal expansion coefficient of the surface direction and the thickness direction was measured in the range of 50-120 degreeC by the compression method using TMA2940 (made by TA Instruments Co., Ltd.).
(3) Drill workability With respect to the above sample, drilling of 20,000 holes was performed with a drill diameter of 0.2 mm, a rotation speed of 300 krpm, a feed rate of 2.1 m / min, two stacked sheets, and an entry board 150 μm aluminum plate. The drill edge wear was measured. In addition, the product number: MD E747S by a union tool company was used for the drill.

[result]
The copper-clad laminates of the examples were found to have excellent substrate appearance, a small coefficient of thermal expansion, and excellent drillability (lifetime).
On the other hand, in Comparative Example 1 in which silica having a small average particle diameter (average particle diameter of 0.5 μm) was used instead of the filler (2), the substrate surface edge was not obtained due to the non-uniform fluidity of silica and aluminum hydroxide. A streak of resin flow occurred in the part, and the appearance of the substrate deteriorated.
Moreover, the comparative example 2 which used the silica (average particle diameter of 0.5 micrometer) with a small average particle diameter with the filler (2) was inferior to drill workability.
Comparative Example 3 containing no filler had a high coefficient of thermal expansion.

Claims (7)

In the prepreg formed by impregnating the base material with the resin composition,
The resin composition contains aluminum hydroxide having an average particle diameter of 2.5 to 4.5 μm, an average particle diameter of 1.0 to 3.0 μm, a specific gravity of 2.3 to 2.6 g / cm ³ and a content of SiO ₂ . Contains 50 to 65 mass% glass filler,
The total amount of the aluminum hydroxide and the glass filler in the total solid content of the resin composition is 30 to 50% by mass ,
A prepreg in which the usage ratio of the aluminum hydroxide and the glass filler is 4: 6 to 6: 4 .   The prepreg according to claim 1, wherein the resin composition has a non-halogenated epoxy compound having at least two epoxy groups in one molecule. The prepreg according to claim 1 or 2, wherein the resin composition contains a phosphorus-containing curing agent represented by the following chemical formula (1).

(However, R is an organic group having two or more phenolic hydroxyl groups and a molecular weight of 180 or more.) The organic group represented by R in the chemical formula (1) has one or more types of structures selected from the following chemical formulas (2), (3), (4), (5), and (6). And the prepreg of Claim 3 which has 2 or more of phenolic hydroxyl groups.
(* In chemical formulas (2) to (6) indicates a site directly bonded to the phosphorus atom of chemical formula (1).)

(R ¹ in the chemical formula (5) is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and R ² is an alkyl group having 1 to 4 carbon atoms. N is the number of OR ² groups in the aromatic ring. Yes, and any one of 1 to 3. In addition, ^RA is an organic group having two or more phenolic hydroxyl groups.)

(R ¹ in chemical formula (6) is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and R ² is an alkyl group having 1 to 4 carbon atoms. N is the number of OR ² groups in the aromatic ring. There are either 1-3. also, R ^B is an organic group having two or more phenolic hydroxyl groups.) The organic group represented by R in the chemical formula (1) has one or more of the structures selected from the following chemical formulas (7), (8) and (9), and has two or more phenolic hydroxyl groups. The prepreg according to claim 4.
(* In chemical formulas (7) to (9) indicates a site directly bonded to the phosphorus atom of chemical formula (1).)

  A metal-clad laminate obtained by stacking one or more prepregs according to any one of claims 1 to 5, placing metal foil on both sides or one side, and heating and pressing.   A printed wiring board obtained by wiring a metal layer of the metal-clad laminate according to claim 6.