JP2014172983A - Prepreg and copper-clad substrate having the same as insulating layer - Google Patents

Abstract

It is suitable for a copper-clad substrate that has high processing accuracy in via formation by laser and can form vias with high processing accuracy with few laser shots, especially in high energy laser processing by direct laser method. Prepreg.
A prepreg obtained by impregnating a glass cloth with a thermosetting resin composition having a glass transition point after curing of 170 to 300 ° C. The thermosetting resin composition contains a polyfunctional epoxy resin, a phenol resin and a thermosetting resin component (A) containing a imidazole curing agent, a phosphoric acid amide compound, and a phosphoric acid ester compound. A flame retardant component (B) and an inorganic filler component (C) containing aluminum hydroxide and silica as essential components are contained as essential components. Moreover, the content rate of the inorganic filler component (C) in the said thermosetting resin composition is 40-80 mass%.
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Description

  The present invention relates to a prepreg and a copper-clad substrate using the same as an insulating layer, and more particularly to a prepreg having a specific configuration for providing a copper-clad substrate suitable for forming a via by direct laser processing, and the insulating layer. To a copper-clad substrate.

  A prepreg used as an insulating material for printed wiring boards is made by impregnating a glass cloth with a thermosetting resin composition having electrical performance, thermal characteristics, mechanical characteristics, and processing characteristics, and is used for such prepregs. As the thermosetting resin composition to be applied, for example, resin compositions containing an epoxy resin, a phenol resin, a phosphoric acid flame retardant and an inorganic filler are disclosed (Patent Documents 1 and 2).

  Further, it is disclosed that a flame retardant epoxy resin composition obtained by adding phosphoric acid amide as a flame retardant to an epoxy resin composition is used as a prepreg (Patent Document 3).

  In recent years, as the printed wiring board is highly integrated, the board has been miniaturized and multi-layered, and high precision laser processing is used for forming the via. In addition, in order to shorten the process time, it has been required to form vias with fewer laser shots.

  As a method of forming fine vias on a printed wiring board by laser, a method of forming vias using laser after removing copper foil, and drilling both conductive layers and insulating layers at once by laser. A direct laser method (Patent Documents 4 and 5) for forming vias is known. In particular, in the case of this direct laser method, since it is necessary to irradiate a high energy laser, it is difficult to form a via with high processing accuracy.

JP 2002-105287 A JP 2008-291056 A JP 2001-354836 A JP 2002-124769 A JP 2007-129147 A

Accordingly, a first object of the present invention is to provide a prepreg suitable for forming a via with high processing accuracy using a laser.
A second object of the present invention is to provide a copper-clad substrate capable of forming a via with high accuracy even by a direct laser method using a small number of laser shots.

  The present inventors have found that a prepreg obtained by impregnating a glass cloth with a thermosetting resin composition having a specific composition having a glass transition point after curing of 170 to 300 ° C. solves the above problem. The present invention has been reached.

  That is, the present invention is a prepreg obtained by impregnating a glass cloth with a thermosetting resin composition having a glass transition point after curing of 170 to 300 ° C., wherein the thermosetting resin composition is a polyfunctional epoxy resin. A thermosetting resin component (A) containing a phenol resin and an imidazole curing agent, a phosphoric acid flame retardant component (B) containing a phosphoric acid amide compound and a phosphoric ester compound, and aluminum hydroxide and A prepreg containing an inorganic filler component (C) containing silica as an essential component and a content of the inorganic filler component (C) in the thermosetting resin composition of 40 to 80% by mass. And a copper-clad substrate, wherein the prepreg is an insulating layer.

  In the prepreg of the present invention, the polyfunctional epoxy resin is preferably at least one polyfunctional epoxy resin selected from the group consisting of a biphenylene aralkyl type epoxy resin, a cresol novolac epoxy resin, and a tetrafunctional epoxy resin. The phenol resin used together with the other functional epoxy resin is preferably a biphenylene aralkyl type phenol resin.

The phosphoric acid amide compound is preferably a phosphoric acid amide compound represented by the following general formula (1).

However, in the formula, R ^{01 to} R ²⁰ are a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms or a halogen atom, Z ¹ and Z ² are direct bonds, and 1 to 4 carbon atoms. An alkanediyl group, an alkylidene group having 1 to 4 carbon atoms, X ¹ is an arylene group having 6 to 18 carbon atoms, a cycloalkylene group having 6 to 18 carbon atoms, an arylene-alkylene-arylene group having 13 to 18 carbon atoms, or carbon It is an arylene-alkylidene-arylene group of several 13 to 18.

Moreover, it is preferable that the said phosphate ester compound is a phosphate ester represented by following General formula (2).

However, ^R 21 ^{to R 28} in the formula is a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or cycloalkyl group, or a halogen atom having 3 to 8 carbon atoms, ^{A 1} and ^{A 2} are hydrogen atoms, or, They are linked by a single bond, and X ² is a hydrogen atom or a dihydroxyaryl group.

  By using the prepreg of the present invention for a copper-clad substrate, it is possible to form a via with a laser with high processing accuracy. In addition, even in the direct laser method, formation of a via with high processing accuracy with a small number of laser shots. Became possible.

FIG. 1 is an explanatory view of a cross section of a copper clad substrate measured in an example.

As for the thermosetting resin composition in the prepreg of this invention, the glass transition temperature after hardening needs to be 170-300 degreeC, and it is preferable that it is 170-280 degreeC.
In the present invention, the glass transition temperature is the IPC standard TM-650 No. According to 2.4.4.24.2, the temperature is a temperature at which the loss tangent, which is a value obtained by measuring dynamic viscoelasticity by the DMA method and dividing the loss elastic modulus by the storage elastic modulus, exhibits a maximum value.

If the glass transition temperature is lower than 170 ° C., sufficient processing accuracy in forming vias by laser cannot be obtained.
On the other hand, if the glass transition temperature exceeds 300 ° C., it is necessary to increase the laser energy or increase the number of shots in order to perform the processing, so that the processing efficiency is lowered.

  The thermosetting resin component (A) used in the prepreg of the present invention is required to have a composition having good coating properties on the glass cloth at the time of prepreg production and workability in the impregnation step. It contains an epoxy resin, a phenol resin, and an imidazole curing agent as essential components.

The polyfunctional epoxy resin contained as an essential component in the thermosetting resin component (A) has two or more epoxy groups in the molecular structure.
Specifically, polyglycidyl ether compounds derived from mononuclear polyphenol compounds such as hydroquinone, resorcin, pyrocatechol, phloroglucinol; dihydroxynaphthalene, biphenol, methylene bisphenol (bisphenol F), methylene bis (orthocresol), Ethylidene bisphenol, isopropylidene bisphenol (bisphenol A), isopropylidene bis (orthocresol), tetrabromobisphenol A, 1,3-bis (4-hydroxycumylbenzene), 1,4-bis (4-hydroxycumylbenzene) ), 1,1,3-tris (4-hydroxyphenyl) butane, 1,1,2,2-tetra (4-hydroxyphenyl) ethane, thiobisphenol, sulfonylbisphenol, oxybi Polyglycidyl ether compounds derived from polynuclear polyphenol compounds such as phenol; poly derived from phenol novolac resins such as phenol novolak, cresol novolak, ethylphenol novolak, butylphenol novolak, octylphenol novolak, resorcin novolak, terpene phenol novolak Glycidyl ether compound; polyglycidyl ether compound derived from alkylene aralkyl type phenol resin, cycloalkylene aralkyl type phenol resin; ethylene glycol, propylene glycol, butylene glycol, hexanediol, polyglycol, thiodiglycol, glycerin, trimethylolpropane, Pentaerythritol, sorbitol, bisphenol A-eth Polyglycidyl ether compounds derived from polyhydric alcohols such as oxide adducts; maleic acid, fumaric acid, itaconic acid, succinic acid, glutaric acid, suberic acid, adipic acid, azelaic acid, sebacic acid, dimer acid, trimer acid From aliphatic, aromatic or cycloaliphatic polybasic acids such as phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, trimesic acid, pyromellitic acid, tetrahydrophthalic acid, hexahydrophthalic acid, endomethylenetetrahydrophthalic acid Derived glycidyl esters; and homopolymers or copolymers of glycidyl methacrylate; N, N-diglycidylaniline, bis (4- (N-methyl-N-glycidylamino) phenyl) methane, diglycidyl orthotoluidine, etc. An epoxy compound having a glycidylamino group; Vinylcyclohexene diepoxide, dicyclopentanediene diepoxide, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, 3,4-epoxy-6-methylcyclohexylmethyl-6-methylcyclohexanecarboxylate, bis ( 3,4-epoxy-6-methylcyclohexylmethyl) epoxides of cyclic olefin compounds such as adipate; epoxidized conjugated diene polymers such as epoxidized polybutadiene and epoxidized styrene-butadiene copolymer; complex such as triglycidyl isocyanurate A ring compound is mentioned.
In addition, these epoxy resins may contain polyvalent active hydrogens such as polyphenols, polyamines, carbonyl group-containing compounds, polyphosphates, even if they are internally cross-linked by a prepolymer having an isocyanate group at the end. It may be a polymer having a high molecular weight.
In the present invention, these polyfunctional epoxy resins are used alone or in combination of two or more.

  In the prepreg of the present invention, from the viewpoint that the glass transition temperature, the application to the glass cloth at the time of prepreg production, and the workability in the impregnation process are good, from the biphenylene aralkyl type epoxy resin, the cresol novolac epoxy resin and the tetrafunctional epoxy resin It is preferable to use at least one epoxy resin selected from the group consisting of:

The biphenylene aralkyl type epoxy resin is represented by the following general formula (3).

However, R < ¹⁰¹ > -R < ¹¹⁶ > in a formula is a group represented by a hydrogen atom, a halogen atom, a C1-C10 alkyl group, a C2-C10 alkenyl group, or following General formula (4). , R ^{117 to} R ¹³¹ represent a hydrogen atom, a halogen atom or an alkyl group having 1 to 10 carbon atoms, and m is a number from 0 to 100.
However, R < ¹³² > -R < ¹³⁵ > in a formula is a hydrogen atom, a halogen atom, a C1-C10 alkyl group, or a C2-C10 alkenyl group, T is a direct bond, a methylene group, an ethylidene group, a propylidene group. , Oxygen atom, sulfur atom or SO ₂ .

Examples of the halogen atom represented by R ^{101 to} R ¹¹⁶ and R ^{117 to} R ^{131 in the} general formula (3) and R ^{132 to} R ¹³⁵ in the general formula (4) include fluorine, chlorine, bromine, and iodine. Examples of the alkyl group having 1 to 10 carbon atoms include methyl, ethyl, propyl, isopropyl, butyl, secondary butyl, tertiary butyl, isobutyl, amyl, isoamyl, tertiary amyl, hexyl, 2-hexyl, 3-hexyl, and cyclohexyl. , 1-methylcyclohexyl, heptyl, 2-heptyl, 3-heptyl, isoheptyl, tertiary heptyl, n-octyl, isooctyl, tertiary octyl, 2-ethylhexyl, nonyl, isononyl, decyl, and the like. Examples of the alkenyl group having 2 to 10 carbon atoms include vinyl, 1-methylethenyl, 2-methylethenyl, propenyl, butenyl, isobutenyl, pentenyl, hexenyl, heptenyl, octenyl, decenyl and the like.

Among the biphenylene aralkyl type epoxy resins, those in which R ^{101 to} R ¹³¹ are hydrogen atoms and m is 2 to 20 are suitable because they are inexpensive. In particular, it is possible to impart better heat resistance to the cured resin, and when preparing a thermosetting resin composition having a glass transition point of 170 to 300 ° C., the range of the blending amount of other components In view of the fact that a large value can be obtained, it is preferable to use a biphenylene aralkyl type epoxy resin having m of 5 to 20.

The cresol novolac type epoxy resin is represented by the following general formula (5).
However, n in a formula is a number of 0-30.
In particular, in the production of a prepreg, from the viewpoint that it is optimal to use a solid state epoxy resin, in the cresol novolac resin, n in the general formula (5) is preferably 5 to 30. 5 to 20 is preferred.

As said tetrafunctional epoxy resin, what is represented by following General formula (6) is mentioned.
However, Y ⁵ in the formula is a hydrocarbon group having an aromatic ring, unsubstituted or substituted with a halogen atom, the diglycidylamino group and the glycidyloxy group are directly bonded to the aromatic ring, and x is 0 1 or 2 and y is 4-2x.
In the general formula (6), examples of the halogen atom that is substituted into Y ⁵ include fluorine, chlorine, bromine, and iodine.

Specific examples of the tetrafunctional epoxy resin represented by the general formula (6) include compounds represented by the following general formulas (6-1) to (6-4).


However, R < ²⁹ > -R < ⁷² >, R < ⁷⁵ > -R < ⁸⁴ > in a formula is respectively independently a hydrogen atom, a halogen atom, or a methyl group, R ^<73> and R ^<74> is respectively independently a hydrogen atom or a methyl group, Q is An oxygen atom, a methylene group, or a group represented by the following general formula (6-5).
However, R ^{85 to} R ⁸⁸ in the formula are each independently a hydrogen atom, a halogen atom or a methyl group, and R ⁸⁹ and R ⁹⁰ are each independently a hydrogen atom or a methyl group.

Further, specific examples of the tetrafunctional epoxy resin include the following Nos. 1-No. 8 compounds.

  The phenol resin contained as an essential component in the thermosetting resin component (A) in the present invention is a resin composed of a novolak type, a resorcin type, or a mixture thereof obtained by a reaction between phenols and formaldehyde. Examples of the phenols include phenol, cresol, ethylphenol, n-propylphenol, isopropylphenol, butylphenol, tert-butylphenol, octylphenol, nonylphenol, dodecylphenol, cyclohexylphenol, chlorophenol, bromophenol, resorcin, catechol, hydroquinone. 2,2-bis (4-hydroxyphenyl) propane, 4,4′-thiodiphenol, dihydroxydiphenylmethane, naphthol, terpenephenol, biphenylaralkyl-modified phenol, phenolized dicyclopentadiene, and the like as aldehydes Is formaldehyde. These phenolic resins may be used alone or in combination of two or more.

In the present invention, an optimal glass transition temperature can be obtained, and in the process of applying or impregnating a glass cloth with a curable resin composition during prepreg production, the following general formula can be obtained. It is preferable to use a biphenylene aralkyl type phenol resin represented by (7).
However, ^R 201 ^{to R 216} is a hydrogen atom in the formula, a halogen atom, an alkyl group having 1 to 10 carbon atoms, a group represented by the alkenyl group having 2 to 10 carbon atoms, or the following general formula ^{(8), R 217} to R ²³¹ is a hydrogen atom, a halogen atom or an alkyl group having 1 to 10 carbon atoms, p is a number from 0 to 100.
However, R < ²³² > -R < ²³⁵ > in a formula is a hydrogen atom, a halogen atom, a C1-C10 alkyl group, or a C2-C10 alkenyl group, and T 'is a direct bond, a methylene group, an ethylidene group, propylidene. Group, oxygen atom, sulfur atom or SO ₂ —.

Examples of the halogen atom represented by R ^{201 to} R ²¹⁶ and R ^{217 to} R ²³¹ in the general formula (7) and R ^{232 to} R ²³⁵ in the general formula (8) include fluorine, chlorine, bromine, and iodine. Examples of the alkyl group having 1 to 10 carbon atoms include methyl, ethyl, propyl, isopropyl, butyl, secondary butyl, tertiary butyl, isobutyl, amyl, isoamyl, tertiary amyl, hexyl, 2-hexyl, 3-hexyl, and cyclohexyl. , 1-methylcyclohexyl, heptyl, 2-heptyl, 3-heptyl, isoheptyl, tertiary heptyl, n-octyl, isooctyl, tertiary octyl, 2-ethylhexyl, nonyl, isononyl, decyl, and the like. Examples of the alkenyl group having 2 to 10 carbon atoms include vinyl, 1-methylethenyl, 2-methylethenyl, propenyl, butenyl, isobutenyl, pentenyl, hexenyl, heptenyl, octenyl, decenyl and the like.

As the phenol resin of the general formula (7), those in which R ^{201 to} R ²³¹ are hydrogen atoms are inexpensive and easily available. Furthermore, p in the general formula (7) is preferably 1 to 50, and more preferably 4 to 40.

  The imidazole compound contained as an essential component in the thermosetting resin component (A) is a compound having a function as a curing agent that cures the thermosetting resin component by heat. The imidazole compound is not particularly limited, and for example, one or more known imidazole compounds used as a curing agent for epoxy resins may be used in combination.

  Examples of the imidazole compound include 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 1,2-dimethylimidazole, and 2-ethyl. -4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl 2-undecylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, 1-cyanoethyl-2-pheni Imidazolium trimellitate, 2,4-diamino-6- [2'-methylimidazolyl- (1 ')]-ethyl-s-triazine, 2,4-diamino-6- [2'-undecylimidazolyl- ( 1 ′)]-ethyl-s-triazine, 2,4-diamino-6- [2′-ethyl-4′-methylimidazolyl- (1 ′)]-ethyl-s-triazine, 2,4-diamino-6 -[2'-methylimidazolyl- (1 ')]-ethyl-s-triazine isocyanuric acid adduct, 2-phenylimidazole isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4 -Methyl-5-hydroxymethylimidazole, 2,3-dihydro-1H-pyrrolo [1,2-a] benzimidazole, 1-dodecyl-2-methyl-3- Emissions Jill imidazolium chloride, 2-methyl-imidazoline, 2-phenyl-imidazoline, and the like.

  As the imidazole compound used in the present invention, a compound that gives a curing temperature and a curing speed suitable as the prepreg production conditions may be selected. In particular, by using imidazoles having a phenyl group at the 2-position, the curing temperature of the curable resin composition can be increased, and the heat resistance of the resin cured product can be improved.

  In the thermosetting resin component (A) according to the present invention, the blending ratio of the polyfunctional epoxy resin, the phenol resin, and the imidazole curing agent, which are essential components, is 10 parts by mass with respect to 100 parts by mass of the polyfunctional epoxy resin. It is preferable that it is -100 mass parts and an imidazole compound is 1-25 mass parts.

Moreover, in the thermosetting resin component (A) which concerns on this invention, in the range which can hold | maintain the glass transition point after hardening of curable resin composition at 170-300 degreeC, as needed, other A curable component may be contained.
Examples of the other components include cyanate resins, phenoxy resins, and silane coupling agents.
The compounding amount of these curable components is usually 100 parts by mass or less and preferably 30 parts by mass or less with respect to 100 parts by mass of the polyfunctional epoxy resin. In the present invention, it is particularly preferable to use a silane coupling agent that improves adhesion to glass cloth, and the amount used is 1 to 10 parts by mass with respect to 100 parts by mass of the polyfunctional epoxy resin. preferable.

  The silane coupling agent is not particularly limited as long as it is a silicon compound having a functional group that reacts with a resin component and a functional group that reacts with glass cloth, and a well-known silane coupling agent can be used. In the present invention, it has an epoxy group, an amino group, an isocyanate group, or a mercapto group that reacts with an organic functional group possessed by an epoxy resin and a phenol resin, or an organic functional group formed by the reaction thereof, and a substrate or inorganic It is preferable to use a silane coupling agent having a silanol group or an alkoxysilyl group as the group that reacts with the filler component (C).

  Examples of the suitable silane coupling agent component include 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidpropyltrimethoxysilane, 3-glycidpropylpropylmethyldiethoxysilane, 3- Glycidpropyltriethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, N-2- (aminoethyl)- 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N- (1,3-dimethylbutylidene) propylamine, N-phenyl-3- Aminopropyltrimethoxysilane, 3-isocyanatopropyl Triethoxysilane, 3-isocyanate propyl trimethoxysilane, 3-mercaptopropyl trimethoxysilane, 3-mercaptopropyl methyl dimethoxy silane, and the like.

The phosphoric acid flame retardant component (B) used in the prepreg of the present invention contains a phosphoric acid amide compound and a phosphoric acid ester compound.
As the phosphoric acid amide compound, various phosphoric acid amide compounds that are usually used as flame retardants can be used. Examples of the phosphoric acid amide compound include compounds in which piperazine and organic amines and phosphoric acid selected from phosphoric acid, pyrophosphoric acid, metaphosphoric acid or partial esters of these phosphoric acids form an amide bond.

  In particular, from the viewpoint of obtaining a prepreg having a good film thickness uniformity and improving the processing accuracy of a copper-clad substrate by a laser, the phosphoric acid amide compound in the present invention is represented by the following general formula (1). It is preferred to use a compound which is

However, in the formula, R ^{01 to} R ²⁰ are a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms or a halogen atom, Z ¹ and Z ² are direct bonds, and 1 to 4 carbon atoms. An alkanediyl group, an alkylidene group having 1 to 4 carbon atoms, and X ¹ is an arylene group having 6 to 18 carbon atoms, a cycloalkylene group having 6 to 18 carbon atoms, and an arylene-alkylene-arylene group having 13 to 18 carbon atoms. Or an arylene-alkylidene-arylene group having 13 to 18 carbon atoms.

Examples of the alkyl group having 1 to 8 carbon atoms represented by R ^{01 to} R ²⁰ in the general formula (1) include methyl, ethyl, propyl, isopropyl, butyl, secondary butyl, tertiary butyl, isobutyl, amyl, Isoamyl, tertiary amyl, hexyl, 2-hexyl, 3-hexyl, cyclohexyl, 1-methylcyclohexyl, heptyl, 2-heptyl, 3-heptyl, isoheptyl, tertiary heptyl, n-octyl, isooctyl, tertiary octyl, 2 -Cycloalkyl group having 3 to 10 carbon atoms includes cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, methylcyclohexyl, dimethylcyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, and halogen atom. The Iodine, chlorine, bromine, and iodine.

Examples of the alkanediyl group having 1 to 4 carbon atoms represented by Z ¹ and Z ² include methylene, ethylene, propane-1,3-diyl, propane-1,2-diyl, butylene, butane-1,3-diyl. , Butane-2,3-diyl and butane-1,2-diyl. Examples of the alkylidene group having 1 to 4 carbon atoms include methylidene, dimethylmethylidene, ethylmethylmethylidene, diethylmethylidene, and methylpropylmethylidene. Is mentioned.

An arylene group having 6 to 18 carbon atoms, a cycloalkylene group having 6 to 18 carbon atoms, an arylene-alkylene-arylene group having 13 to 18 carbon atoms, or an arylene-alkylidene-arylene group having 13 to 18 carbon atoms represented by X ¹ Of the arylene groups having 6 to 18 carbon atoms are 1,2-phenylene, 1,3-phenylene, 1,4-phenylene, 2,5-dimethyl-1,4-phenylene, naphthalene-1,2- Diyl, naphthalene-1,3-diyl, naphthalene-1,4-diyl, naphthalene-1,5-diyl, naphthalene-1,6-diyl, naphthalene-1,7-diyl, naphthalene-1,8-diyl, Naphthalene-2,3-diyl, naphthalene-2,6-diyl, naphthalene-2,7-diyl, diphenyl sulfide-4,4′-diyl, diphenyl Rufon-4,4′-diyl and the like, and examples of the cycloalkylene group having 6 to 18 carbon atoms include cyclohexane-1,1-diyl, cyclohexane-1,2-diyl, cyclohexane-1,3-diyl, , 5,5-trimethylcyclohexane-1,3-diyl, 1-methylcyclohexane-1,3-diyl, cyclohexane-1,4-diyl, cycloheptane-1,1-4-diyl, cyclooctane-1,1 -5-diyl, cyclononane-1,1-5-diyl, cyclodecane-1,1-6-diyl, and the arylene-alkylidene-arylene group having 13 to 18 carbon atoms includes diphenylmethane-4,4'- Diyl, 1,1-diphenylethane-4,4′-diyl, 2,2-diphenylpropane-4,4′-diyl, 2,2-diphenyl Down-4,4'-diyl, 2,2-di (3,3'-dimethyl) propane-4,4'-diyl, and the like.

Specific examples of the phosphoric acid amide compound represented by the general formula (1) are as follows. 9-No. 21 compounds are mentioned.

As the phosphoric ester compound, various phosphoric ester compounds that are usually used as flame retardants can be used. For example, trimethyl phosphate, triethyl phosphate, tributyl phosphate, tributoxyethyl phosphate, trischloroethyl phosphate, trisdichloropropyl phosphate, triphenyl phosphate, tricresyl phosphate, cresyl diphenyl phosphate, trixylenyl phosphate, octyl diphenyl phosphate, xyl Renyl diphenyl phosphate, trisisopropylphenyl phosphate, 2-ethylhexyl diphenyl phosphate, t-butylphenyl diphenyl phosphate, bis (tertiary butylphenyl) phenyl phosphate, tris (tertiary butylphenyl) phosphate, isopropylphenyl diphenyl phosphate, bis (isopropyl Phenyl) diphenyl phosphate, Examples include ris (isopropylphenyl) phosphate, 1,3-phenylene bis (diphenyl phosphate), 1,3-phenylene bis (dixylenyl phosphate), bisphenol A, bis (diphenyl phosphate), etc. From the viewpoint of improving the processing accuracy by the laser, it is preferable to use a phosphate ester compound represented by the following general formula (2).

However, ^R 21 ^{to R 28} in the formula is a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group or a halogen atom having 3 to 8 carbon atoms, ^{A 1} and ^{A 2} are linked hydrogen atom or together X ² is a group that forms a single bond, and X ² is a hydrogen atom or a dihydroxyaryl group.

Examples of the alkyl group having 1 to 8 carbon atoms represented by R ^{21 to} R ²⁸ in the general formula (2) include methyl, ethyl, propyl, isopropyl, butyl, secondary butyl, tertiary butyl, isobutyl, amyl, Isoamyl, tertiary amyl, hexyl, 2-hexyl, 3-hexyl, cyclohexyl, 1-methylcyclohexyl, heptyl, 2-heptyl, 3-heptyl, isoheptyl, tertiary heptyl, n-octyl, isooctyl, tertiary octyl, 2 -Cycloalkyl group having 3 to 10 carbon atoms includes cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, methylcyclohexyl, dimethylcyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, and halogen atom. The Iodine, chlorine, bromine, and iodine.

Specific examples of the phosphoric acid ester compound represented by the general formula (2) are as follows. 22-No. 27 compounds are mentioned.

  If the amount of the phosphoric acid flame retardant component (B) according to the present invention is small, sufficient flame retardancy may not be obtained, and if it is large, the processing accuracy of vias by laser may be lowered. Therefore, it is preferable that the usage-amount of (B) component in this invention is 3-50 mass parts with respect to 100 mass parts of said thermosetting resin components (A), and it is more preferable that it is 5-30 mass parts. preferable.

  In addition, regarding the blending ratio of the phosphoric acid amide compound and the phosphoric acid ester compound in the phosphoric acid flame retardant component (B), if the amount of the phosphoric acid ester compound is small, flame retardancy may not be sufficiently obtained, If it is too large, the processing accuracy of vias by laser may be lowered, and the substrate moldability may be deteriorated. Therefore, it is preferable that it is 30-300 mass parts with respect to 100 mass parts of phosphoric acid amide compounds, and, as for the usage-amount of a phosphoric ester compound, it is more preferable that it is 50 mass parts-200 mass parts.

  The inorganic filler component (C) in the thermosetting resin composition used for the prepreg of the present invention contains aluminum hydroxide and silica as essential components. Aluminum hydroxide is used to improve the flame retardancy of the prepreg, and the content of aluminum hydroxide in the inorganic filler component (C) is preferably 10% by mass to 40% by mass. If it is less than 10% by mass, sufficient flame retardancy may not be obtained, and if it exceeds 40% by mass, the processing accuracy by the laser may be deteriorated.

  Silica is used for suppressing thermal expansion of the prepreg, improving insulation, improving mechanical strength, and the like. In the present invention, it is particularly preferable to use spherical fused silica. It is preferable that the content rate of the silica in an inorganic filler (C) is 60 mass%-90 mass%.

  In this invention, the content rate of the inorganic filler component (C) in a thermosetting resin composition needs to be 40-80 mass%. When the content of the inorganic filler component (C) is less than 40% by mass, the thermal properties, mechanical properties, low fluidity and flame retardance necessary for the prepreg cannot be obtained, and when it exceeds 80% by mass, the prepreg is produced. There are cases where the workability of the steel deteriorates.

  In addition to aluminum hydroxide and silica, other inorganic fillers may be used for the inorganic filler (C). Examples of inorganic fillers that can be used include silicates such as talc, calcined clay, unfired clay, mica and glass; oxides such as titanium oxide, alumina, magnesium oxide and zirconium oxide; calcium carbonate, magnesium carbonate and hydro Carbonates such as talcite; metal hydroxides such as magnesium hydroxide and calcium hydroxide; sulfates or sulfites such as barium sulfate, calcium sulfate and calcium sulfite; zinc borate, barium metaborate, aluminum borate, boron Examples thereof include borates such as calcium acid and sodium borate; nitrides such as aluminum nitride, boron nitride, silicon nitride and carbon nitride; fiber fillers such as glass fiber and carbon fiber; silica sand; cement and the like. These may be used alone or in combination of two or more.

  These fillers may be used within a range in which the intended use effect can be obtained without impairing the effects of the present invention. The content rate of these fillers in an inorganic filler component (C) is 1-20 mass% normally.

You may add another additive to the thermosetting resin composition used for the prepreg of this invention as needed.
Examples of the other additives that can be used in the present invention include plasticizers such as natural waxes, synthetic waxes and metal salts of long-chain aliphatic acids, acid amides, esters, paraffins and the like. Molding agents, stress relaxation agents such as nitrile rubber and butadiene rubber, coupling agents such as titanate coupling agents and aluminum coupling agents, coloring agents such as dyes and pigments, oxidation stabilizers, light stabilizers, and improved moisture resistance Agents, thixotropy imparting agents, diluents, antifoaming agents, other various resins, tackifiers, antistatic agents, lubricants and ultraviolet absorbers. Also, alcohols, ethers, acetals, ketones, esters, alcohol esters, ketone alcohols, ether alcohols, ketone ethers, ketone esters and ester ethers, organic solvents such as aromatic solvents, etc. May be blended.

  The glass cloth used in the prepreg of the present invention is not particularly limited, and may be selected according to the use of the prepreg. In the case of a prepreg for a multilayer substrate, the thickness of the glass cloth is usually 10 μm to 60 μm, the diameter of the glass filament is about 3 to 10 μm, and the number of filaments per fiber is about 150 to 250 per inch. About 50 to 80 fibers are used both vertically and horizontally.

  The prepreg of the present invention is obtained by impregnating the above-mentioned thermosetting resin composition into a glass cloth, and its production method is not particularly limited, and a well-known method can be used. What is necessary is just to set the thickness of a prepreg suitably according to the design of a printed wiring board, and it is 20-50 micrometers normally. A prepreg is manufactured by immersing a glass cloth in a thermosetting resin composition, or by impregnating a glass cloth with a thermosetting resin by applying a thermosetting resin to the glass cloth and then heat-curing the glass cloth. . Furthermore, when the thermosetting resin composition contains an organic solvent, a step of drying the solvent may be added before heating. Moreover, heating temperature is 80-230 degreeC normally, and heating time is 1-10 minutes.

The copper clad substrate of the present invention is characterized in that the prepreg of the present invention is used as an insulating layer, and the insulating layer may be a single layer or a multilayer. Further, the number of prepregs used per insulating layer may be one or two or more. The manufacturing method and configuration of the copper-clad substrate of the present invention are not particularly limited, and are the same as in the case of a known copper-clad substrate.
In particular, the prepreg and the copper-clad substrate of the present invention are suitable for multilayer printed wiring boards because vias with high processing accuracy can be formed with few laser shots in high-energy laser processing. Applications of the prepreg and copper-clad substrate of the present invention include an IC package substrate, a CSP substrate, a super-multilayer copper-clad substrate for special communications, and the like.

  Hereinafter, the resin composition of the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

[Production Example 1: Thermosetting resin composition No. 1]
[A: Thermosetting resin component]
Biphenylene aralkyl type epoxy resin (NC-3000FH manufactured by Nippon Kayaku Co., Ltd.): 15 parts by mass of Compound No. 1: 20 parts by mass Cresol novolac type epoxy resin (EOCN-104S manufactured by Nippon Kayaku Co., Ltd.): 65 parts by mass phenoxy resin (YP-70 manufactured by Toto Kasei): 8.6 parts by mass Biphenylene aralkyl type phenol resin (manufactured by Meiwa Kasei Co., Ltd.) MEH-7851-4H): 31 parts by mass 2-phenylimidazole: 0.5 parts by mass N-phenyl-3-aminopropyltrimethoxysilane: 2.7 parts by mass [B: phosphoric acid flame retardant component]
Phosphoric acid amide compound 9:12 parts by mass Phosphate ester compound 25:12 parts by mass [C: inorganic filler component]
Aluminum hydroxide: 31 parts by mass Spherical silica: 125 parts by mass Fused silica: 0.84 parts by mass Filler component content: 48%

[Production Example 2: Thermosetting resin composition No. 2]
[A: Thermosetting resin component]
Bisphenol A type epoxy resin (EP-4100E manufactured by ADEKA): 20 parts by mass Biphenylene aralkyl type epoxy resin (NC-3000F manufactured by Nippon Kayaku Co., Ltd.): 30 parts by mass Compound No. 1: 20 parts by mass Cresol novolac type epoxy resin (EOCN-104S manufactured by Nippon Kayaku Co., Ltd.): 30 parts by mass biphenylene aralkyl type phenol resin (MEH-7851-H manufactured by Meiwa Kasei Co., Ltd.): 31 parts by mass 2-phenylimidazole: 0 0.5 parts by mass 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane: 1.7 parts by mass [B: phosphoric acid flame retardant component]
Phosphoric acid amide compound no. 9:16 parts by mass Phosphate ester compound No. 25:16 parts by mass [C: inorganic filler component]
Aluminum hydroxide: 34 parts by mass Crushed silica: 136 parts by mass Filler component content: 51%

[Comparative Production Example 1: Comparative Thermosetting Resin Composition No. 1]
[A: Thermosetting resin component]
(Thermosetting resin)
Bisphenol A type epoxy resin (JER-1001 manufactured by Mitsubishi Chemical Corporation): 20 parts by mass Bisphenol A type epoxy resin (EP-4100E manufactured by ADEKA): 40 parts by mass Phenol-dicyclopentadiene type epoxy resin (manufactured by Dainippon Ink, Inc.) -7200): 40 parts by mass butyral resin (B-11TX manufactured by Changchun Plastics Co., Ltd.): 9.7 parts by mass biphenylene aralkyl type phenol resin: (MEH-7851-H manufactured by Meiwa Kasei Co., Ltd.): 73 parts by mass 2-phenylimidazole : 0.2 part by mass [B: Phosphoric acid flame retardant component]
Phosphoric acid amide compound no. 9: 8.9 parts by mass [C: inorganic filler component]
Aluminum hydroxide: 73 parts by mass Filler component content: 28%

[Comparative Production Example 2: Comparative thermosetting resin composition No. 2]
[A: Thermosetting resin component]
Bisphenol A type epoxy resin (EP-4100E, manufactured by ADEKA): 40 parts by mass Phenol-dicyclopentadiene type epoxy resin (HP-7200, manufactured by Dainippon Ink): 35 parts by mass Biphenylene aralkyl type epoxy resin (manufactured by Nippon Kayaku Co., Ltd.) NC-3000): 35 parts by mass Compound No. 1:10 parts by mass Biphenylene aralkyl type phenol resin (MEH-7851-H manufactured by Meiwa Kasei Co., Ltd.): 37 parts by mass 2-phenylimidazole: 0.2 parts by mass [B: phosphoric acid flame retardant component]
Phosphoric acid amide compound no. 9:12 parts by mass [C: inorganic filler component]
Aluminum hydroxide: 144 parts by mass Filler component content: 46%

[Comparative Production Example 3: Comparative thermosetting resin composition No. 3]
[A: Thermosetting resin component]
Biphenylene aralkyl type epoxy resin (NC-3000FH manufactured by Nippon Kayaku Co., Ltd.): 15 parts by mass of Compound No. 1: 20 parts by mass Cresol novolac type epoxy resin (EOCN-104S manufactured by Nippon Kayaku Co., Ltd.): 65 parts by mass phenoxy resin (YP-70 manufactured by Toto Kasei): 8.6 parts by mass Biphenylene aralkyl type phenol resin (manufactured by Meiwa Kasei Co., Ltd.) MEH-7851-4H): 31 parts by mass 2-phenylimidazole: 0.5 parts by mass N-phenyl-3-aminopropyltrimethoxysilane: 2.7 parts by mass [B: phosphoric acid flame retardant component]
Phosphoric ester compound no. 25:24 parts by mass [C: inorganic filler component]
Aluminum hydroxide: 31 parts by mass Spherical silica: 125 parts by mass Fused silica: 0.84 parts by mass Filler component content: 48%

[Comparative Production Example 4: Comparative thermosetting resin composition No. 4]
[A: Thermosetting resin component]
Biphenylene aralkyl type epoxy resin (NC-3000FH, manufactured by Nippon Kayaku Co., Ltd.): 55 parts by mass Cresol novolac type epoxy resin (EOCN-104S manufactured by Nippon Kayaku Co., Ltd.): 45 parts by mass phenoxy resin (YP-70, manufactured by Toto Kasei) Mass parts biphenylene aralkyl type phenol resin (MEH-7851-4H manufactured by Meiwa Kasei Co., Ltd.): 30 parts by mass 2-phenylimidazole: 0.5 parts by mass N-phenyl-3-aminopropyltrimethoxysilane: 1.5 parts by mass [ B: Phosphate flame retardant component]
Phosphoric acid amide compound no. 9:14 parts by mass Phosphate ester compound No. 9 25:14 parts by mass [C: inorganic filler component]
Aluminum hydroxide: 40 parts by weight Spherical silica: 125 parts by weight Filler component content: 50%

[Comparative Production Example 5: Comparative thermosetting resin composition No. 5]
[A: Thermosetting resin component]
Biphenylene aralkyl type epoxy resin (NC-3000FH manufactured by Nippon Kayaku Co., Ltd.): 15 parts by mass of Compound No. 1: 20 parts by mass Cresol novolac type epoxy resin (EOCN-104S manufactured by Nippon Kayaku Co., Ltd.): 65 parts by mass phenoxy resin (YP-70 manufactured by Toto Kasei): 8.6 parts by mass Biphenylene aralkyl type phenol resin (manufactured by Meiwa Kasei Co., Ltd.) MEH-7851-4H): 31 parts by mass 2-phenylimidazole: 0.5 parts by mass N-phenyl-3-aminopropyltrimethoxysilane: 2.7 parts by mass [B: phosphoric acid flame retardant component]
Phosphoric acid amide compound no. 9:12 parts by mass of the phosphoric acid ester compound No. 25:12 parts by mass [C: inorganic filler component]
Aluminum hydroxide: 18 parts by mass Spherical silica: 74 parts by mass Fused silica: 0.5 parts by mass Filler component content: 36%

[Measurement of glass transition temperature]
The thermosetting resin composition Nos. Obtained in the above production examples and comparative production examples. 1 and comparative thermosetting resin compositions 1 to 5 were cured under conditions of 190 ° C. and 90 minutes under a pressure of 30 kg / cm ² , respectively, to obtain cured products. About the obtained hardened | cured material, IPC specification TM-650 No. Based on 2.4.4.2, the dynamic viscoelasticity was measured by the DMA method, and the temperature at which the loss tangent, which is a value obtained by dividing the loss elastic modulus by the storage elastic modulus, was a maximum value was defined as the glass transition temperature.
For measuring dynamic viscoelasticity, a dynamic viscoelasticity measuring device (DMS6100: manufactured by Seiko Instruments Inc.) was used, and the temperature rising rate was 5 ° C./min and the measurement wavelength was 1 Hz.
The results are shown below.
Thermosetting resin composition No. 1: 200 ° C
Thermosetting resin composition No. 2: 175 ° C
Comparative thermosetting resin composition No. 1: 150 ° C
Comparative thermosetting resin composition No. 2: 165 ° C
Comparative thermosetting resin composition No. 3: 180 ° C
Comparative thermosetting resin composition No. 4: 160 ° C
Comparative thermosetting resin composition No. 5: 200 ° C

  Thermosetting resin composition No. 1 was mixed with 100 parts by mass, methyl ethyl ketone 40 parts by mass and propylene glycol monomethyl ether 20 parts by mass to obtain a varnish. The obtained varnish was applied to a glass cloth substrate of PC standard 1086 with a dip coater, heated at 130 ° C. for 10 minutes, and prepreg No. 80 having a thickness of 80 μm. 1 was produced.

  Thermosetting resin composition No. In place of thermosetting resin composition No. 1 A prepreg No. 80 μm thick was prepared in the same manner as in Example 1 except that No. 2 was used. 2 was produced.

[Comparative Examples 1-5]
Thermosetting resin composition No. In place of comparative thermosetting resin composition No. 1 Comparative prepregs A to E having a thickness of 80 μm were produced in the same manner as in Example 1 except that 1 to 5 were used.

The prepreg No. obtained in Example 1 above. A copper foil having a thickness of 12 μm is laminated on both surfaces of the substrate 1 and pressed under the conditions of 190 ° C., 90 minutes, 30 kg / cm ² . 1 was obtained.

  The prepreg No. obtained in Example 2 above. A copper-clad board No. 2 was prepared in the same manner as in Example 3 except that No. 2 was used. 2 was obtained.

[Comparative Examples 6 to 10]
Prepreg No. Comparative copper-clad substrates A to E were obtained in the same manner as in Example 3 except that comparative prepregs A to E were used instead of 1.

[Evaluation]
About each copper-clad board | substrate obtained by the said Example 3, Example 4, and Comparative Examples 6-10, 400 direct laser processing by 2 shots on the following conditions was performed.
[Processing conditions]
Laser source: ML-605GTW-III (Mitsubishi Electric Corporation)
Laser shape: Top flat Energy 1st time: Power: 31 mJ, Pulse width: 38 μsec
Second time: Power; 18 mJ, pulse width; 24 μsec

  About each processed copper-clad board | substrate, the processing precision was evaluated from the upper part image and cross-sectional image by the optical microscope of an upper part and a cross section.

1. From the upper image, the average roundness, the minimum roundness and the maximum diameter difference of the processed via were evaluated.
The roundness is the ratio (%) of the small diameter to the large diameter in the combination in which the difference between the two orthogonal diameters is the largest, and the average roundness is the average of the measured values of 400 vias. And the smallest measured value was defined as the minimum roundness.
The difference between the minimum value and the maximum value of the via diameter was defined as the maximum diameter difference.

2. From the cross-sectional images, the average overhang value and the maximum value (μm), the protrusion of the vertical glass cloth of the via (μm), and the thickness uniformity of the insulating layer were evaluated.
The overhang is the portion 6 in FIG. 1, and the via perpendicularity is the angle (θ) formed between the inner wall of the via (FIGS. 1 and 5) and the bottom surface of the substrate (FIGS. 1 and 1). The length of the glass cloth 8 protruding into the via.
In addition, the uniformity of the thickness of the insulating layer is determined by measuring the thickness of any 50 locations of the insulating layer formed by curing the prepreg, calculating an average value, and calculating the maximum and minimum values of the thickness. When the difference from the average value was less than 5% of the average value, the evaluation was ○, and the evaluation was 5 × or more.
The results are shown in Table 1.

  From the above results, it was confirmed that the copper-clad substrate manufactured using the prepreg of the present invention can be processed with high accuracy by direct laser processing.

  Since the prepreg of the present invention can provide a copper-clad substrate with high processing accuracy, it is suitable for manufacturing an IC package substrate, a CSP substrate, and an ultra-high multi-layer substrate for special communications, and is extremely useful industrially.

1. 1. Copper-clad substrate 2. Insulating layer Copper foil4. Via 5 Via inner wall6. 6. Overhang Glass cloth8. Glass cloth protrusion

Claims (6)

  A prepreg obtained by impregnating a glass cloth with a thermosetting resin composition having a glass transition point after curing of 170 to 300 ° C., wherein the thermosetting resin composition comprises a polyfunctional epoxy resin, a phenol resin, and an imidazole. A thermosetting resin component (A) containing a system curing agent, a phosphoric acid flame retardant component (B) containing a phosphoric acid amide compound and a phosphate ester compound, and aluminum hydroxide and silica as essential components A prepreg characterized by containing an inorganic filler component (C) to be contained as an essential component and a content of the inorganic filler component (C) in the thermosetting resin composition being 40 to 80% by mass or more.   The prepreg according to claim 1, wherein the polyfunctional epoxy resin is at least one polyfunctional epoxy resin selected from the group consisting of a biphenylene aralkyl epoxy resin, a cresol novolac epoxy resin, and a tetrafunctional epoxy resin.   The prepreg according to claim 1 or 2, wherein the phenol resin is a biphenylene aralkyl type phenol resin. The prepreg according to any one of claims 1 to 3, wherein the phosphoric acid amide compound is a phosphoric acid amide compound represented by the following general formula (1);
However, ^R 01 ^{to R 20} in the formula is a hydrogen atom, a halogen atom, an alkyl group or a cycloalkyl group having 3 to 10 carbon atoms having 1 to 8 carbon atoms, ^{Z 1} and ^{Z 2} is a direct bond, C 1 -C -4 alkanediyl group or alkylidene group having 1 to 4 carbon atoms, ^{X 1} is an arylene group having 6 to 18 carbon atoms, cycloalkylene group having 6 to 18 carbon atoms, an arylene of 13-18 carbon atoms - alkylene - arylene Or an arylene-alkylidene-arylene group having 13 to 18 carbon atoms. The prepreg according to any one of claims 1 to 4, wherein the phosphate ester compound is a phosphate ester compound represented by the following general formula (2);
However, ^R 21 ^{to R 28} in the formula is a hydrogen atom, a halogen atom, an alkyl group or a cycloalkyl group having 3 to 8 carbon atoms having 1 to 8 carbon atoms, ^{A 1} and ^{A 2} is a hydrogen atom, Alternatively, they are linked by a single bond, and X ² is a hydrogen atom or a dihydroxyaryl group.   A copper-clad board, wherein the prepreg according to claim 1 is used as an insulating layer.