JP2010218975A - Insulating sheet, laminated plate, and multilayer laminated plate - Google Patents

Abstract

An insulating sheet capable of increasing the adhesive strength of a conductor layer when the conductor layer is formed on the surface of a cured product.
A polymer (A) having a surface arithmetic average roughness Ra of 0.1 μm or more and 3 μm or less and a weight average molecular weight of 10,000 or more, and an epoxy resin (B1 having a weight average molecular weight of less than 10,000) ) And at least one of the oxetane resins (B2) having a weight average molecular weight of less than 10,000 (B2), a curing agent (C), and a filler having an average particle size in the range of 0.1 to 5 μm. (D), and the content of the said filler (D) in 100 volume% of insulating sheets is in the range of 20-90 volume%.
[Selection] Figure 1

Description

  The present invention relates to an insulating sheet used to form an insulating layer such as a multilayer laminate, and more specifically, when the conductor layer is formed on the surface of a cured product, the adhesive strength of the conductor layer can be increased. The present invention relates to an insulating sheet that can be formed, and a laminated board and a multilayer laminated board using the insulating sheet.

  In recent years, electronic devices such as mobile phones and computers have been reduced in size and speeded up information processing. For this reason, in the printed wiring board used for the said electronic device, multilayering and a thin film are progressing, and the mounting density of an electronic component is increasing.

  Conventionally, as a method for producing a multilayer printed wiring board, a method of laminating and pressing an inner circuit board on which a circuit is formed and a copper foil through several prepreg sheets as an insulating adhesive layer is used. The prepreg sheet is generally a sheet that is made into a B-stage by impregnating a glass cloth with an epoxy resin. However, the above method requires a long time for the laminating press and further requires a large facility, which increases the manufacturing cost. For this reason, in recent years, a build-up type multilayer printed wiring board manufacturing method in which insulating layers are alternately stacked on a conductor layer of an inner circuit board has been widely adopted.

  The insulating sheet used for the build-up method is required to have handling properties at room temperature and appropriate fluidity to satisfactorily laminate the inner layer circuit.

  As an example of the insulating sheet, the following Patent Document 1 discloses an insulating adhesive in which a glass cloth is impregnated with an adhesive composition containing an epoxy resin, an epoxy resin curing agent, a curing accelerator, an elastomer, and an inorganic filler. A sheet is disclosed. Patent Document 2 below discloses an epoxy resin composition containing an epoxy resin having two or more epoxy groups in one molecule, a phenol resin composition, a rubber component, and a curing accelerator. Yes. The phenol resin composition is a mixture or condensate of phenols, a compound having a triazine ring and an aldehyde, and the mixture or condensate is substantially free of unreacted aldehydes and methylol groups.

JP 2006-342238 A Japanese Patent No. 378549

  The insulating sheet described in Patent Document 1 has low flexibility because a glass cloth is used. For this reason, the inner layer circuit could not be laminated satisfactorily. In addition, when glass cloth is used, it may be difficult to reduce the film thickness, the laser processability may be inferior, or sufficient heat dissipation may not be obtained due to the low thermal conductivity of the glass cloth itself. It was.

  Patent Document 2 describes that minute irregularities can be formed on the surface only by thermosetting the epoxy resin composition. For this reason, when the insulating layer of a printed wiring board is formed with the said epoxy resin composition, and the conductor layer is formed in the surface of the insulating layer, the adhesive strength of an insulating layer and a conductor layer becomes high. However, even when the epoxy resin composition is used, the adhesive strength between the insulating layer and the conductor layer may not be sufficiently high. Moreover, since the insulating sheet described in Patent Document 2 is not filled with a filler having a high thermal conductivity, the heat dissipation may be low.

  An object of the present invention is to provide an insulating sheet capable of increasing the adhesive strength of a conductor layer when a conductor layer is formed on the surface of a cured product, and a laminated board and a multilayer laminated board using the insulating sheet. It is.

  According to the present invention, the polymer (A) having a surface arithmetic average roughness Ra of 0.1 μm or more and 3 μm or less and a weight average molecular weight of 10,000 or more, and an epoxy resin having a weight average molecular weight of less than 10,000 (B1) and at least one of the oxetane resins (B2) having a weight average molecular weight of less than 10,000 (B2), a curing agent (C), and an average particle diameter within a range of 0.1 to 5 μm. An insulating sheet is provided which contains a filler (D) and the content of the filler (D) in 100% by volume of the insulating sheet is in the range of 20 to 90% by volume.

  The filler (D) is preferably at least one selected from the group consisting of alumina, crystalline silica, synthetic magnesite, boron nitride, aluminum nitride, silicon nitride, silicon carbide, zinc oxide and magnesium oxide. In this case, the heat dissipation of the insulating cured sheet can be further enhanced.

  In a specific aspect of the insulating sheet according to the present invention, the filler (D) is crushed, substantially polyhedral, or plate-shaped.

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

  The curing agent (C) is more preferably a phenol resin having a melamine skeleton or a triazine skeleton, or a phenol resin having an allyl group. By using this preferable curing agent (C), the adhesion between the insulating layer and the conductor layer can be further enhanced. Moreover, the softness | flexibility and flame retardance of an insulating sheet can be improved further.

  The curing agent (C) is obtained by an addition reaction between an acid anhydride having a polyalicyclic skeleton, a water addition of the acid anhydride or a modification of the acid anhydride, or a terpene compound and maleic anhydride. The acid anhydride having an alicyclic skeleton, a water addition of the acid anhydride, or a modified product of the acid anhydride is also preferable. The curing agent (C) is more preferably an acid anhydride represented by any of the following formulas (1) to (3). Use of these preferable hardening | curing agents (C) can further improve the softness | flexibility of a insulating sheet, moisture resistance, or adhesiveness.

  In said formula (3), R1 and R2 show hydrogen, a C1-C5 alkyl group, or a hydroxyl group, respectively.

  In another specific aspect of the insulating sheet according to the present invention, resin particles (E) are further included.

  In still another specific aspect of the insulating sheet according to the present invention, the polymer (A) is a polymer having an aromatic skeleton and having a weight average molecular weight of 30,000 or more. The polymer (A) is preferably a phenoxy resin. Use of the phenoxy resin can further enhance the heat resistance of the insulating cured sheet. Moreover, it is preferable that the glass transition temperature of the said phenoxy resin is 95 degreeC or more. In this case, the thermal deterioration of the resin can be further suppressed.

  In another specific aspect of the insulating sheet according to the present invention, the resin (B) has an aromatic skeleton, and has an epoxy monomer (B1b) having a weight average molecular weight of 600 or less and an aromatic skeleton, And at least one of oxetane monomers (B2b) having a weight average molecular weight of 600 or less.

  In still another specific aspect of the insulating sheet according to the present invention, in a total of 100% by weight of the resin components in the insulating sheet including the polymer (A), the resin (B), and the curing agent (C). The content of the polymer (A) is 20 to 60% by weight, the content of the resin (B) is 10 to 60% by weight, and the total content of the polymer (A) and the resin (B) is Less than 100% by weight.

  The laminated board according to the present invention comprises an insulating layer and a conductor layer laminated on at least one surface of the insulating layer, and the insulating cured sheet is obtained by curing the insulating sheet configured according to the present invention. It is formed by.

  A multilayer laminate according to the present invention includes a plurality of laminated insulating layers and a conductor layer disposed between the plurality of insulating layers, and the insulating layer cures an insulating sheet configured according to the present invention. It is formed with the insulation hardening sheet made to make.

  On the specific situation with the multilayer laminated board which concerns on this invention, the said conductor layer is formed by plating.

  The present invention is an insulating sheet containing a filler (D) having an average particle size of 0.1 to 5 μm together with the components (A) to (C), and has an arithmetic average roughness Ra of 0.1 μm or more and 3 μm or less. Therefore, when the conductor layer is formed on the surface of the cured product, the adhesive strength between the cured product and the conductor layer can be sufficiently increased.

  The laminate and multilayer laminate according to the present invention include an insulating layer and a conductor layer, and the insulating layer is formed of an insulating cured sheet obtained by curing an insulating sheet configured according to the present invention. Adhesive strength with the layer can be sufficiently increased.

FIG. 1 is a partially cutaway front sectional view schematically showing a laminate using an insulating sheet according to an embodiment of the present invention. FIG. 2 is a partially cutaway front cross-sectional view schematically showing a multilayer laminate using an insulating sheet according to an embodiment of the present invention. FIG. 3 is a partially cutaway front cross-sectional view schematically showing a laminated structure using an insulating cured sheet according to an embodiment of the present invention.

  Details of the present invention will be described below.

  The insulating sheet according to the present invention comprises a polymer (A) having a weight average molecular weight of 10,000 or more, an epoxy resin (B1) having a weight average molecular weight of less than 10,000, and an oxetane resin having a weight average molecular weight of less than 10,000 ( B2) includes at least one resin (B), a curing agent (C), and a filler (D) having an average particle diameter in the range of 0.1 to 5 μm.

(Polymer (A))
The polymer (A) contained in the insulating sheet according to the present invention is not particularly limited as long as the weight average molecular weight is 10,000 or more. The polymer (A) preferably has an aromatic skeleton. In this case, the heat resistance of the insulating cured sheet can be further enhanced. When the polymer (A) has an aromatic skeleton, the aromatic skeleton may be included in the whole polymer, may be included in the main chain skeleton, and may be included in the side chain. Also good. The polymer (A) preferably has an aromatic skeleton in the main chain skeleton. In this case, the heat resistance of the insulating cured sheet can be further enhanced. As for a polymer (A), only 1 type may be used and 2 or more types may be used together.

  The aromatic skeleton is not particularly limited. Specific examples of the aromatic skeleton include naphthalene skeleton, fluorene skeleton, biphenyl skeleton, anthracene skeleton, pyrene skeleton, xanthene skeleton, adamantane skeleton, and bisphenol A skeleton. Of these, a biphenyl skeleton or a fluorene skeleton is preferable. In this case, the heat resistance of the insulating cured sheet can be further enhanced.

  As said polymer (A), a thermoplastic resin, a thermosetting resin, etc. can be used.

  The thermoplastic resin and thermosetting resin are not particularly limited. Examples of the thermoplastic resin and thermosetting resin include thermoplastic resins such as polyphenylene sulfide, polyarylate, polysulfone, polyethersulfone, polyetheretherketone, and polyetherketone. In addition, as the thermoplastic resin and the thermosetting resin, a heat-resistant resin group called a super engineering plastic such as thermoplastic polyimide, thermosetting polyimide, benzoxazine, or a reaction product of polybenzoxazole and benzoxazine, etc. Can be used. As for the said thermoplastic resin and the said thermosetting resin, only 1 type may respectively be used and 2 or more types may be used together. Either one of a thermoplastic resin and a thermosetting resin may be used, and a thermoplastic resin and a thermosetting resin may be used in combination.

  The polymer (A) is preferably a styrene polymer, a (meth) acrylic polymer, or a phenoxy resin, and more preferably a phenoxy resin. In this case, the oxidative deterioration of the insulating cured sheet can be prevented and the heat resistance can be further enhanced.

  Specifically, a homopolymer of a styrene monomer, a copolymer of a styrene monomer and an acrylic monomer, or the like can be used as the styrene polymer. Among these, a styrene polymer having a styrene-glycidyl methacrylate structure is preferable.

  Examples of the styrene monomer include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, p-ethylstyrene, and pn-. Butyl styrene, p-tert-butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, 2,4-dimethyl Examples include styrene and 3,4-dichlorostyrene.

  Examples of the acrylic monomer include acrylic acid, methacrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, acrylate-2-ethylhexyl, cyclohexyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, Examples include butyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, glycidyl methacrylate, ethyl β-hydroxyacrylate, propyl γ-aminoacrylate, stearyl methacrylate, dimethylaminoethyl methacrylate or diethylaminoethyl methacrylate. It is done.

  Specifically, the phenoxy resin is, for example, a resin obtained by reacting an epihalohydrin and a divalent phenol compound, or a resin obtained by reacting a divalent epoxy compound and a divalent phenol compound.

  The phenoxy resin comprises a bisphenol A skeleton, a bisphenol F skeleton, a bisphenol A / F mixed skeleton, a naphthalene skeleton, a fluorene skeleton, a biphenyl skeleton, an anthracene skeleton, a pyrene skeleton, a xanthene skeleton, an adamantane skeleton, and a dicyclopentadiene skeleton. It is preferred to have at least one skeleton selected from the group. Among these, the phenoxy resin preferably has at least one skeleton selected from the group consisting of a bisphenol A skeleton, a bisphenol F skeleton, a bisphenol A / F mixed skeleton, a naphthalene skeleton, a fluorene skeleton, and a biphenyl skeleton. Preferably, it has at least one of a fluorene skeleton and a biphenyl skeleton. By using the phenoxy resin having these preferable skeletons, the heat resistance of the insulating cured sheet can be further enhanced.

  The phenoxy resin preferably has a polycyclic aromatic skeleton in the main chain. Moreover, it is more preferable that the phenoxy resin has at least one skeleton of the skeletons represented by the following formulas (4) to (9) in the main chain.

In the above formula (4), R ₁ may be the same or different from each other, and is a hydrogen atom, a hydrocarbon group having 1 to 10 carbon atoms or a halogen atom, and X ₁ is a single bond, having 1 to 1 carbon atoms. 7 divalent hydrocarbon group, —O—, —S—, —SO ₂ —, or —CO—.

In the above formula (5), R _1a may be the same as or different from each other, and is a hydrogen atom, a hydrocarbon group having 1 to 10 carbon atoms, or a halogen atom, and R ₂ is a hydrogen atom, carbon number 1 10 is a hydrocarbon group having 1 to 10 carbon atoms or a halogen atom, R ₃ is a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, and m is an integer of 0 to 5.

In the above formula (6), R _1b may be the same or different from each other, and is a hydrogen atom, a hydrocarbon group having 1 to 10 carbon atoms or a halogen atom, and R ₄ is the same or different from each other. It is a hydrogen atom, a C1-C10 hydrocarbon group, or a halogen atom, and l is an integer of 0-4.

In the formula (8), _{R 5} and _{R 6} is a hydrogen atom, an alkyl group or a halogen atom having 1 to 5 carbon atoms, _{X 2} is _{-SO 2 -, - CH 2 -} , - C (CH 3) 2 -Or -O-, and k is 0 or 1.

  As the polymer (A), for example, a phenoxy resin represented by the following formula (10) or the following formula (11) is preferably used.

In the above formula (10), A ₁ has a structure represented by any _one of the above formulas (4) to (6), and the structure thereof is 0 to 0. 60 mol%, the structure represented by the above formula (5) is 5 to 95 mol%, and the structure represented by the above formula (6) is 5 to 95 mol%, and A ₂ is a hydrogen atom or the above formula (7) a group represented, _{n 1} is a number of 25 to 500 in average.

In the above formula (11), A ₃ has a structure represented by the above formula (8) or the above formula (9), and n ₂ is a value of at least 21 or more.

  The glass transition temperature Tg of the polymer (A) is preferably in the range of 60 to 200 ° C, and more preferably in the range of 90 to 180 ° C. If the Tg of the polymer (A) is too low, the resin may be thermally deteriorated. If the Tg of the polymer (A) is too high, the compatibility between the polymer (A) and the other resin is deteriorated. As a result, the handling properties of the uncured insulating sheet and the heat resistance of the insulating cured sheet may be reduced.

  When the polymer (A) is a phenoxy resin, the glass transition temperature Tg of the phenoxy resin is preferably 95 ° C. or higher, more preferably in the range of 110 to 200 ° C., and 110 to 180 ° C. More preferably, it is in the range. If the Tg of the phenoxy resin is too low, the resin may be thermally deteriorated. If the Tg of the phenoxy resin is too high, the compatibility between the phenoxy resin and the other resin is deteriorated. As a result, the handling properties of the uncured insulating sheet and the heat resistance of the insulating cured sheet may be reduced.

  The polymer (A) has a weight average molecular weight of 10,000 or more. The weight average molecular weight of the polymer (A) is preferably 30,000 or more, more preferably in the range of 30,000 to 1,000,000, and in the range of 40,000 to 250,000. More preferably it is. If the weight average molecular weight of the polymer (A) is too small, the insulating cured sheet may be thermally deteriorated. When the weight average molecular weight of the polymer (A) is too large, the compatibility between the polymer (A) and another resin is deteriorated. As a result, the handling properties of the uncured insulating sheet and the heat resistance of the insulating cured sheet may be reduced.

  The polymer (A) is in the range of 20 to 60% by weight in 100% by weight of the total resin components contained in the insulating sheet containing the polymer (A), the resin (B), and the curing agent (C). Contained within. The polymer (A) is contained within the above range so that the total content of the polymer (A) and the resin (B) is less than 100% by weight. The minimum with preferable content of the polymer (A) in 100 weight% of total of all the resin components is 30 weight%, and a preferable upper limit is 50 weight%. When there is too little content of a polymer (A), the handleability of an uncured insulating sheet may fall. When there is too much content of a polymer (A), dispersion | distribution of a filler (D) may become difficult. The total resin component means the sum of the polymer (A), the epoxy resin (B1), the oxetane resin (B2), the curing agent (C), and other resin components added as necessary.

(Resin (B))
The insulating sheet according to the present invention contains at least one of the epoxy resin (B1) and the oxetane resin (B2) (B). As the resin (B), only the epoxy resin (B1) may be used, or only the oxetane resin (B2) may be used, and both the epoxy resin (B1) and the oxetane resin (B2) are used. Also good.

  The epoxy resin (B1) has a weight average molecular weight of less than 10,000. The epoxy resin (B1) is not particularly limited as long as the weight average molecular weight is less than 10,000. As the epoxy resin (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 epoxy resin (B1) 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, an epoxy monomer having a fluorene skeleton, and biphenyl. Examples thereof include an epoxy monomer having a 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 an epoxy resin (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 given.

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

  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 or 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, 4,4'-diglycidyl-3,3 ', 5,5'-tetramethylbiphenyl, and the like.

  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 or 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 oxetane resin (B2) has a weight average molecular weight of less than 10,000. The oxetane resin (B2) is not particularly limited as long as the weight average molecular weight is less than 10,000. As the oxetane resin (B2), an oxetane monomer (B2b) having an aromatic skeleton and having a weight average molecular weight of 600 or less is preferably used.

  Specific examples of the oxetane resin (B2) 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, or oxetated phenol novolak. As for oxetane resin (B2), only 1 type may be used and 2 or more types may be used together.

  The weight average molecular weight of the epoxy resin (B1) and the oxetane resin (B2), that is, the weight average molecular weight of the resin (B) is less than 10,000. The weight average molecular weight of the resin (B) is preferably 600 or less. The minimum with a preferable weight average molecular weight of resin (B) is 200, and a more preferable upper limit is 550. If the weight average molecular weight of the resin (B) is too small, the volatility of the resin (B) may be too high and the handleability of the insulating sheet may be lowered. If the weight average molecular weight of the resin (B) is too large, the insulating sheet may be hard and brittle, or the adhesiveness of the insulating cured sheet may be lowered.

  In a total of 100% by weight of all resin components contained in the insulating sheet containing the polymer (A), the resin (B), and the curing agent (C), the resin (B) is in the range of 10 to 60% by weight. It is preferable that it is contained within. It is more preferable that the resin (B) is contained within a range of 10 to 40% by weight in a total of 100% by weight of all the resin components. The resin (B) is preferably contained so that the total content of the polymer (A) and the resin (B) is less than 100% by weight within the above range. When there is too little content of resin (B), the adhesiveness and heat resistance of an insulation hardening sheet may fall. When there is too much content of resin (B), the handleability of an insulating sheet may fall.

  The resin (B) has an aromatic skeleton and an epoxy monomer (B1b) having a weight average molecular weight of 600 or less, and an oxetane monomer (B2b) having an aromatic skeleton and a weight average molecular weight of 600 or less. It is preferable that at least one of the monomers is included.

  The resin (B) is an epoxy monomer (B1b) having an aromatic skeleton and having a weight average molecular weight of 600 or less and an oxetane monomer (B2b) having an aromatic skeleton and having a weight average molecular weight of 600 or less. It is preferable to contain at least one of the monomers within the range of 40 to 100% by weight, more preferably within the range of 60 to 100% by weight, and particularly preferably within the range of 80 to 100% by weight. . When content of an epoxy monomer (B1b) and an oxetane monomer (B2b) exists in the said preferable range, the softness | flexibility of an insulating sheet and the adhesiveness and heat resistance of an insulation hardening sheet 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. 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), an insulating cured sheet having an excellent balance of heat resistance, moisture resistance and electrical properties can be obtained. As for a hardening | curing agent (C), only 1 type may be used and 2 or more types may be used together.

  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. Among these, a phenol resin having a melamine skeleton, a phenol resin having a triazine skeleton, or a phenol resin having an allyl group is preferable, and a phenol resin having a triazine skeleton is more preferable. In this case, the adhesion between the insulating cured sheet and the conductor layer can be further enhanced. Furthermore, the softness | flexibility and flame retardance of an insulating sheet or an insulation hardening sheet can be improved further.

  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 Dainippon Ink, Inc.), 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, or trialkyltetrahydrophthalic anhydride. Of these, methyl nadic acid anhydride or trialkyltetrahydrophthalic anhydride is preferable. By using methyl nadic acid anhydride or trialkyltetrahydrophthalic anhydride, the water resistance of the insulation cured sheet can be increased.

  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 (any of the above Is 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 (any more than Dainippon Ink and Chemicals Co., Ltd.) EPICLON B570, and the like.

  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 adhesiveness of the insulating sheet or the insulating cured sheet can be further enhanced. Examples of the acid anhydride having an alicyclic skeleton, a water addition of the acid anhydride, or a modified product of the acid anhydride include maleated terpinene, methyl nadic acid anhydride, and acid anhydride having a dicyclopentadiene skeleton. Or a modified product of the acid anhydride.

  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.) Etc.

  The curing agent (C) is more preferably an acid anhydride represented by any of the following formulas (1) to (3). By using this preferable hardening | curing agent (C), the softness | flexibility, moisture resistance, or adhesiveness of an insulating sheet or an insulation hardening sheet can be improved further.

  In said formula (3), R1 and R2 show hydrogen, a C1-C5 alkyl group, or a hydroxyl group, respectively.

  In order to adjust the curing rate or the physical properties of the insulating cured sheet, 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, diazabicycloalkenes such as organic acid salts, and the like. 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.

  As the above-mentioned curing accelerator, 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, or 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 amine addition type accelerators in which dicyandiamide or 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. When an imidazole curing accelerator having a high melting point is used, the reaction system can be easily controlled, and the curing speed of the insulating sheet and the physical properties of the insulating cured 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.

  In a total of 100% by weight of all resin components contained in the insulating sheet containing the polymer (A), the resin (B), and the curing agent (C), the curing agent (C) is 10 to 40% by weight. It is preferable that it is contained within the range. The minimum with more preferable content of the hardening | curing agent (C) in the total 100 weight% of the said all resin component is 12 weight%, and a more preferable upper limit is 25 weight%. If the content of the curing agent (C) is too small, it may be difficult to sufficiently cure the insulating sheet. When there is too much content of a hardening | curing agent (C), the excess hardening agent which does not participate in hardening may generate | occur | produce, or bridge | crosslinking may not fully advance in the case of hardening of an insulating sheet. For this reason, the heat resistance and adhesiveness of an insulation hardening sheet may not fully be improved.

(Filler (D))
By including the filler (D) having an average particle diameter of 0.1 to 5 μm in the insulating sheet according to the present invention, the arithmetic average roughness Ra of the surface of the insulating sheet is set to 0.1 μm or more and 3 μm or less. The arithmetic average roughness Ra of the surface of the insulating cured sheet obtained by curing the insulating sheet can be 0.1 μm or more and 3 μm or less. For this reason, the adhesive strength with the conductor sheet formed by plating on the insulating sheet or the insulating cured sheet can be increased. The minimum with a preferable average particle diameter of a filler (D) is 0.2 micrometer, and a more preferable minimum is 0.3 micrometer. The upper limit with a preferable average particle diameter (D) of a filler (D) is 4 micrometers, and a more preferable upper limit is 3 micrometers. When the average particle diameter of the filler (D) satisfies these preferable lower limits or upper limits, the adhesive strength between the insulating cured sheet and the conductor layer can be further increased. In addition, when the average particle diameter of a filler (D) is too small, the unevenness | corrugation formed on the surface of an insulating sheet is too small, and a filler (D) does not contribute to the adhesive improvement of an insulation hardening sheet and a conductor layer. Or it may be difficult to fill the filler (D) at a high density. When the average particle diameter of the filler (D) is too large, the dielectric breakdown characteristics of the insulating cured sheet may be deteriorated.

  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.

  The filler (D) is not particularly limited as long as the average particle diameter is in the range of 0.1 to 5 μm. As for a filler (D), only 1 type may be used and 2 or more types may be used together. The filler (D) is preferably at least one selected from the group consisting of alumina, crystalline silica, synthetic magnesite, boron nitride, aluminum nitride, silicon nitride, silicon carbide, zinc oxide and magnesium oxide. By using these preferable fillers (D), the heat dissipation of the insulating cured sheet can be further enhanced.

  The shape of the filler (D) is preferably crushed, substantially polyhedral or plate-like, and is preferably crushed or substantially polyhedral. When the filler (D) has this preferable shape, irregularities can be formed on the surface of the insulating sheet at a higher density. For this reason, the adhesive strength of an insulation hardening sheet and a conductor layer can be raised further.

  Examples of the crushed filler include crushed alumina. The crushed filler can be obtained, for example, by crushing a massive inorganic substance using a uniaxial crusher, a biaxial crusher, a hammer crusher, a ball mill, or the like.

  The aspect ratio of the crushed filler is not particularly limited. The aspect ratio of the crushed filler is preferably in the range of 1.5-20. The aspect ratio of the crushed filler can be determined, for example, by measuring the crushed surface of the filler using a digital image analysis type particle size distribution measuring device (trade name: FPA, manufactured by Nippon Luft).

  In 100% by volume of the insulating sheet, the filler (D) is preferably contained within a range of 20 to 90% by volume. When the content of the filler (D) is within the above range, the adhesive strength between the insulating cured sheet and the conductor layer can be sufficiently increased. 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. If the content of the filler (D) is too small, the heat dissipation of the insulating sheet cannot be sufficiently increased, or unevenness is not effectively formed on the surface, resulting in low adhesion between the insulating cured sheet and the conductor layer. There are things to do. If the content of the filler (D) is too large, the flexibility and adhesion of the insulating sheet will be remarkably lowered, or if the new Mohs hardness of the filler (D) is high, the insulation cured sheet by drilling or punching press Workability may be deteriorated.

  The thermal conductivity of the filler (D) is preferably 10 W / m · K or more. When the thermal conductivity is 10 W / m · K or less, the heat dissipation of the insulating cured sheet may not be sufficiently exhibited. Since the heat dissipation of the insulating cured sheet can be further enhanced, the thermal conductivity of the filler (D) is more preferably 20 W / m · K or more, and further preferably 30 W / m · K or more.

In the filler (D), anhydrous magnesium carbonate (D1d1) not containing water of crystallization represented by the chemical formula MgCO ₃ and the surface of the anhydrous magnesium carbonate (D1d1) are coated with an organic resin, silicone resin or silica. The filler (Dd1) may be at least one of the covered bodies (D2d1). By using such a filler (Dd1), it is possible to improve the workability of the insulating cured sheet while sufficiently ensuring the thermal conductivity and heat resistance of the insulating cured sheet. Since the insulating sheet of the present invention is excellent in workability, for example, it is possible to suppress wear of equipment used when processing the insulating cured sheet. Therefore, the insulating sheet can be stably produced over a long period.

The anhydrous magnesium carbonate (D1d1) containing no water of crystallization represented by the above chemical formula MgCO ₃ has a relatively good thermal conductivity of 15 W / m · K and a low Mohs hardness of 3.5. Furthermore, the anhydrous magnesium carbonate (D1d1) is less expensive than nitride. Therefore, the production cost of the insulating sheet can be reduced by using the magnesium carbonate salt (D1d1) or the covering (D2d1) containing the magnesium carbonate salt.

Formula MgCO ₃ magnesium carbonate does not contain crystal water represented by anhydrous salt (D1d1), for example different from the hydroxy magnesium carbonate of Formula _{4MgCO 3 · Mg (OH 2)} · 4H 2 O. This hydroxy magnesium carbonate is sometimes simply referred to as magnesium carbonate. When this hydroxy magnesium carbonate is heated to around 100 ° C., it releases crystal water. For this reason, magnesium magnesium carbonate is not suitable for applications requiring high solder heat resistance, for example.

Moreover, there exist a natural product and a synthetic product as anhydrous magnesium carbonate (D1d1) containing no crystal water represented by the chemical formula MgCO ₃ . Since natural products contain impurities, physical properties such as heat resistance may not be stable when natural products are used. For this reason, the anhydrous magnesium carbonate (D1d1) is preferably a synthetic product.

  The covering body (D2d1) has a core / shell structure having magnesium carbonate anhydrous salt (D1d1) as a core and a covering layer formed of an organic resin, silicone resin or silica as a shell. Since the said covering (D2d1) has the said coating layer, the dispersibility to resin is high. Furthermore, the use of the covering body (D2d1) having the covering layer can further increase the acid resistance of the insulating cured sheet.

  The method for coating the surface of the magnesium carbonate anhydrous salt (D1d1) with the coating layer is not particularly limited. As this method, for example, a method of spray-drying a dispersion in which magnesium carbonate anhydrous (D1d1) is dispersed in a solution in which a silane coupling agent that is an organic resin, a silicone resin, or a silica raw material is dissolved, or an organic resin Alternatively, after the magnesium carbonate anhydrous salt (D1d1) is dispersed in the solution in which the silicone resin is dissolved, the organic resin or the poor solvent of the silicone resin is added to the surface of the magnesium carbonate anhydrous salt (D1d1). Method of depositing polysiloxane, reacting a polymerizable monomer such as acrylic resin, styrene resin or low molecular weight silane in a medium in which anhydrous magnesium carbonate (D1d1) is dispersed to make it high molecular weight and cannot be dissolved in the medium A table of anhydrous magnesium carbonate (D1d1) made of organic resin, silicone resin or silica The method and the like to be deposited on.

  The said organic resin will not be specifically limited if the surface of magnesium carbonate anhydrous salt (D1d1) can be coat | covered. The organic resin is preferably a resin that can impart acid resistance to the cured product. The organic resin may be a thermosetting resin or a thermoplastic resin.

  Specific examples of the organic resin include (meth) acrylic resin, styrene resin, urea resin, melamine resin, phenolic resin, thermoplastic urethane resin, thermosetting urethane resin, epoxy resin, thermoplastic polyimide. Resins, thermosetting polyimide resins, aminoalkyd resins, phenoxy resins, phthalate resins, polyamide resins, ketone resins, norbornene resins, polyphenylene sulfide, polyarylate, polysulfone, polyethersulfone, polyetheretherketone, Examples include polyether ketone, thermoplastic polyimide, thermosetting polyimide, benzoxazine, or a reaction product of polybenzoxazole and benzoxazine. Among these, (meth) acrylic resins or styrene resins are preferred because there are many types of monomers, the covering layer can be designed widely, and the reaction can be easily controlled by heat or light.

  Since the acid resistance at the time of etching can be improved, the organic resin preferably contains a crosslinkable monomer having two or more reactive groups in the molecule.

  The thickness of the coating layer is preferably in the range of 10 nm to 1 μm. When the thickness of the coating layer is less than 10 nm, the effect of improving the dispersibility of the cover (D2d1) in the resin and the effect of improving the acid resistance of the insulating cured sheet may not be sufficiently obtained. When the thickness of the coating layer exceeds 1 μm, the thermal conductivity of the coated body (D2d1) may be significantly reduced.

The filler (Dd1) includes spherical magnesium carbonate anhydrous salt (D1d2) not containing water of crystallization represented by the chemical formula MgCO ₃ , and the surface of the spherical magnesium carbonate anhydrous salt (D1d2) is made of organic resin, silicone resin or silica. It is preferable that the filler (Dd2) is at least one of the coated bodies (D2d2). The surface of the spherical magnesium carbonate anhydrous salt (D1d2) is coated with an organic resin, a silicone resin, or silica to make the coated body (D2d2) spherical. The filler (Dd2) is preferably spherical. In the case of a spherical shape, the insulating sheet can be filled with the filler (Dd2) at a high density, and therefore the heat dissipation of the insulating cured sheet can be enhanced. Furthermore, the dielectric breakdown characteristics of the insulating cured sheet can be enhanced.

  The spherical shape is not limited to a true spherical shape. The spherical shape includes a shape in which the true sphere is slightly flattened or distorted. For example, a spherical shape has a shape with an aspect ratio in the range of 1 to 1.5, or many parts of the surface, for example, 30% or more of the surface is not a flat surface but a curved surface, and a part of the surface For example, a shape in which less than 70% of the surface is not a curved surface but a flat surface or the like is included. A shape in which 50% or more of the surface is a curved surface is more preferable, and a shape in which a portion of 70% or more of the surface is a curved surface is more preferable.

  The spherical magnesium carbonate anhydrous salt (D1d2), the coated body (D2d2) or the spherical filler (Dd2) using the spherical magnesium carbonate anhydrous salt is pulverized by a jet mill or a rotating rotor and a stator. -It is preferable that it is spheroidized by a surface treatment apparatus. By such a spheronization treatment, the sphericity can be increased, and a spherical shape or a shape close to a spherical shape can be obtained. Furthermore, the aggregate of filler (Dd2) can be crushed by the spheroidizing treatment. Therefore, the filler (Dd2) can be filled in the insulating sheet at a high density. For this reason, the heat dissipation of an insulation hardening sheet can be improved further. Furthermore, the dielectric breakdown characteristics of the insulating cured sheet can be further enhanced.

  Two or more types of fillers (Dd1) having different shapes may be used to form a densely packed structure in the insulating sheet to enhance the heat dissipation of the insulating cured sheet, and two or more types of fillers having different particle sizes. (Dd1) may be used.

The filler (Dd1) has a substantially polyhedral magnesium carbonate anhydrous salt (D1d3) not containing water of crystallization represented by the chemical formula MgCO ₃ , and the surface of the substantially polyhedral magnesium carbonate anhydrous salt (D1d3) is an organic resin, It is also preferable that it is at least one filler (Dd3) in the covering (D2d3) covered with silicone resin or silica. The surface of the substantially polyhedral magnesium carbonate anhydrous salt (D1d3) is coated with an organic resin, silicone resin, or silica, whereby the coated body (D2d3) can be formed into a substantially polyhedral shape. The filler (Dd3) is preferably substantially polyhedral. In addition, when the filler (Dd3) has a substantially polyhedral shape, other fillers other than the filler (Dd3) are further included, and the other fillers are preferably plate-like fillers.

  When the filler (Dd3) is substantially polyhedral and includes a plate-like filler, the filler (Dd3) and the plate-like filler are not in point contact but in surface contact in the insulating sheet, and the filler (Dd3) and The contact area with the plate filler is increased. In addition, a plurality of fillers (Dd3) dispersed at a distance in the insulating sheet contact or approach each other via the plate-like filler, so that each filler in the insulating sheet is bridged or efficiently approached. It becomes the structure made. For this reason, the heat conductivity of an insulation hardening sheet can be made still higher.

  The average major axis of the plate-like filler is in the range of 0.1 to 5 μm. By using the filler (Dd3) and the plate filler, the filler (Dd3) and the plate filler can be sufficiently brought into contact with each other in the insulating sheet. For this reason, the heat conductivity of an insulation hardening sheet can be made still higher. In addition, when a filler (D) is a plate-shaped filler, the average particle diameter of a filler (D) shows an average major axis.

  The “substantially polyhedral shape” includes not only a polyhedron shape constituted only by a plane, which is a general definition of a polyhedron, but also a shape having a curved surface with a plane and a certain ratio or less. The substantially polyhedral shape includes, for example, a shape constituted by a curved surface of 10% or less of the surface and a plane of 90% or more of the surface. The substantially polyhedral shape is preferably a substantially cubic shape or a substantially rectangular parallelepiped shape.

  When the average major axis of the plate-like filler is less than 0.1 μm, it is difficult to fill the plate-like filler, or the plate-like filler is used to bridge the substantially polyhedral filler (Dd3) efficiently and sufficiently. May not be possible. A more preferable lower limit of the average major axis of the plate-like filler is 0.5 μm, and a more preferable lower limit is 1 μm.

  The average thickness of the plate-like filler is preferably 100 nm or more. When the thickness of the plate filler is 100 nm or more, the thermal conductivity of the cured product can be further increased. The aspect ratio of the plate filler is preferably in the range of 2-50. When the aspect ratio of the plate filler exceeds 50, it may be difficult to fill the plate filler. The aspect ratio of the plate filler is more preferably in the range of 3 to 45.

  The plate-like filler is preferably at least one of alumina and boron nitride. In this case, the thermal conductivity of the insulating cured sheet can be further increased. In particular, the combined use of the filler (Dd3) and at least one of alumina and boron nitride can further increase the thermal conductivity of the insulating cured sheet.

  When the filler (Dd1) and other fillers other than the filler (Dd1) are used in combination, the blending amount seems to be optimal depending on the type, particle size and shape of the filler (Dd1) and other fillers. To be determined. The total content of the filler (Dd1) and other fillers in 100% by volume of the insulating sheet is preferably in the range of 60 to 90% by volume. If the total content of the filler (Dd1) and other fillers is less than 60% by volume, the heat dissipation of the cured product may not be sufficiently improved. When the total content of the filler (Dd1) and the other filler (D) exceeds 90% by volume, the flexibility or adhesiveness of the insulating sheet may be significantly reduced.

  When the filler (Dd1) and other fillers are used in combination, the content of the filler (Dd1) in 100% by volume of the insulating sheet is more preferably in the range of 20 to 80% by volume.

  In the insulating sheet, the substantially polyhedral filler (Dd3) and the plate filler are preferably contained in a volume ratio of 70:30 to 99: 1. The total content of the substantially polyhedral filler (Dd3) and the plate filler in 100% by volume of the insulating sheet is preferably in the range of 60 to 90% by volume. The content of the filler (Dd3) and the plate-like filler in the insulating sheet is 70:30 to 99: 1 by volume, and the filler (Dd3) and the plate are contained in 100% by volume of the insulating sheet. The total content with the filler is more preferably in the range of 60 to 90% by volume. When content of the said filler (Dd3) and the said plate-shaped filler exists in the said preferable range, respectively, the workability and heat conductivity of an insulation hardening sheet can be made still higher.

(Resin particles (E))
The insulating sheet according to the present invention preferably contains resin particles (E). When the insulating sheet contains the resin particles (E), the heat resistance reliability of the insulating cured sheet can be further increased. In addition, when the resin particles (E) are used, the resin particle portions are dropped off during repeated chemical treatment and cleaning in the printed wiring board manufacturing process, and finer irregularities are formed on the surface. The adhesion between the sheet and the conductor layer may be enhanced.

  The resin particles (E) are not particularly limited. Examples of the resin particles (E) include acrylic rubber, butadiene rubber, isoprene rubber, acrylonitrile butadiene rubber, styrene butadiene rubber, styrene isoprene rubber, urethane rubber, silicone rubber, fluorine rubber, or natural rubber. Especially, it is preferable that the resin particle (E) is an acrylic rubber particle or a silicone rubber particle, and it is more preferable that it is a silicone rubber particle. By using these preferable resin particles (E), it is possible to make the unevenness on the surface of the insulating cured sheet much finer, and to increase the stress relaxation property of the insulating cured sheet, thereby improving the flexibility of the insulating cured sheet. It can be increased, and a decrease in heat resistance of the insulating cured sheet can be suppressed. Further, the properties of the resin particles (E) are not particularly limited.

  By the combined use of the resin particles (E) and the filler (D), the coefficient of linear thermal expansion of the insulating cured sheet can be lowered and the stress relaxation property of the insulating cured sheet can be expressed. Furthermore, peeling or cracking of the insulating cured sheet is further less likely to occur under high temperature conditions or cooling cycle conditions.

  The resin particles (E) are preferably contained within a range of 0.1 to 40% by weight in 100% by weight of the insulating sheet. The minimum with more preferable content of the resin particle (E) in 100 weight% of insulating sheets is 0.3 weight%, and a more preferable upper limit is 20 weight%. When there is too little content of the resin particle (E), the stress relaxation property of an insulation hardening sheet may not fully express. When there is too much content of the resin particle (E), the adhesiveness of an insulation hardening sheet may become low.

(Other ingredients)
The insulating sheet according to the present invention may contain a dispersant (F). By using the dispersant (F), the thermal conductivity and dielectric breakdown characteristics of the insulating cured sheet can be further enhanced. Examples of the functional group containing the hydrogen atom having hydrogen bonding property of the dispersant (F) include a carboxyl group (pKa = 4), a phosphoric acid group (pKa = 7), and a phenol group (pKa = 10). Is mentioned.

  The pKa of the functional group containing the hydrogen atom having hydrogen bonding property of the dispersant (F) is preferably in the range of 2 to 10, and more preferably in the range of 3 to 9. When the pKa of the functional group is less than 2, the acidity of the dispersant (F) becomes too high, and the reaction of the epoxy component and the oxetane component in the raw resin component may be facilitated. Therefore, when the uncured insulating sheet is stored, the storage stability of the insulating sheet may be reduced. When pKa of the said functional group exceeds 10, the function as a dispersing agent may not fully be fulfilled, but the heat conductivity and dielectric breakdown characteristic of an insulation hardening sheet may not fully be improved.

  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 insulating cured sheet can be further enhanced.

  Specific examples of the dispersant (F) include polyester carboxylic acid, polyether carboxylic acid, polyacrylic carboxylic acid, aliphatic carboxylic acid, polysiloxane carboxylic acid, polyester phosphoric acid, Polyether phosphoric acid, polyacrylic phosphoric acid, aliphatic phosphoric acid, polysiloxane phosphoric acid, polyester phenol, polyether phenol, polyacrylic phenol, aliphatic phenol or polysiloxane phenol It is done. As for a dispersing agent (F), only 1 type may be used and 2 or more types may be used together.

  The dispersant (F) is preferably contained within a range of 0.01 to 20% by weight in 100% by weight of the insulating sheet. The minimum with more preferable content of the dispersing agent (F) in 100 weight% of insulating sheets is 0.1 weight%, and a more preferable upper limit is 10 weight%. When content of a dispersing agent (F) exists in the said range, aggregation of the said filler (D) can be suppressed and the heat conductivity and dielectric breakdown characteristic of an insulation hardening sheet can fully be improved.

  The insulating sheet preferably does not contain a base material, and particularly preferably does not contain glass cloth. When the insulating sheet does not contain the base material, the thickness of the insulating sheet can be reduced, and the thermal conductivity of the insulating sheet can be further increased. 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 an insulation hardening 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 copper foil is not present or in an uncured state.

  Moreover, the insulating sheet of this invention may contain the additive as needed. Examples of additives include thixotropic agents such as barium sulfate, talc, mica, clay, kaolin, diatomaceous earth, or calcium carbonate, flame retardants such as aluminum hydroxide, magnesium hydroxide, and phosphorus flame retardants, silicones, and fluorines. Or polymer-based antifoaming agents, silicone-based, fluorine-based or polymer-based leveling agents, phthalocyanine blue, phthalocyanine green, iodin green, disazo yellow, titanium oxide, carbon black and other colorants. .

(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 20 μm, a further preferable lower limit is 30 μm, a more preferable upper limit is 200 μm, and a further preferable upper limit is 120 μm. If the thickness is too thin, the insulating property of the insulating cured sheet may be lowered. When thickness is too thick, the heat dissipation of an insulation hardening sheet may fall.

  The glass transition temperature Tg of the uncured insulating sheet is preferably 25 ° C. or lower. When the glass transition temperature exceeds 25 ° C., it may be hard and brittle at room temperature. For this reason, the handleability of the uncured insulating sheet may be reduced.

  By curing the insulating sheet, an insulating cured sheet can be obtained.

  When the curing of the insulating sheet proceeds, the insulating sheet is cured or semi-cured. The insulating cured sheet includes not only a cured product that has been cured, but also a semi-cured product in a semi-cured state.

  The heating temperature when the curing of the insulating sheet proceeds is not particularly limited. The minimum with a preferable heating temperature is 130 degreeC, a more preferable minimum is 150 degreeC, and a preferable upper limit is 240 degreeC. If the heating temperature is too low, the insulating sheet is not sufficiently cured, so that the heat resistance or chemical resistance of the insulating cured sheet may be inferior. If the heating temperature is too high, the resin may be deteriorated during curing.

  The arithmetic average roughness Ra of the insulating sheet according to the present invention is not less than 0.1 μm and not more than 3 μm. For this reason, when the conductor layer is formed on the surface of the insulating cured sheet obtained by curing the insulating sheet, the adhesive strength between the insulating cured sheet and the conductor layer can be sufficiently increased. A preferable lower limit of the arithmetic average roughness Ra is 0.2 μm. A preferable upper limit of the arithmetic average roughness Ra is 2 μm, and a more preferable upper limit is 1 μm. If the arithmetic average roughness Ra is too large, the insulating property of the insulating layer may be lowered, or the conductor loss may be increased when fine wiring is formed. The arithmetic average roughness Ra can be obtained by a measurement method based on JIS B0601: 2001.

  The heat conductivity of the insulating cured sheet is preferably 0.5 W / m · K or more. The thermal conductivity of the insulating cured sheet is more preferably 1.0 W / m · K or more, and further preferably 3.0 W / m · K or more. If the thermal conductivity is too low, the heat dissipation of the insulating cured sheet may be lowered.

  The dielectric breakdown voltage of the insulating cured sheet is preferably 30 kV / mm or more. The dielectric breakdown voltage of the insulating cured sheet is more preferably 40 kV / mm or more, further preferably 50 kV / mm or more, further preferably 80 kV / mm or more, and 100 kV / mm or more. Most preferred. If the dielectric breakdown voltage is too low, the insulation may be lowered when the insulation-cured sheet is used for large current applications such as for power elements.

  The reaction rate of the uncured insulating sheet is preferably 10% or less. When the reaction rate of the uncured insulating sheet exceeds 10%, the uncured insulating sheet becomes hard and brittle, and the handling property of the uncured insulating sheet at room temperature decreases, or the insulating cured sheet adheres. May deteriorate. The reaction rate of the insulating sheet is obtained by calculating from the amount of heat generated when the insulating sheet is cured in two stages of 120 ° C. for 1 hour and then 200 ° C. for 1 hour using a differential scanning calorimeter.

  The bending elastic modulus at 25 ° C. of the uncured insulating sheet is preferably in the range of 10 to 1,000 MPa, and more preferably in the range of 20 to 500 MPa. When the bending elastic modulus at 25 ° C. of the uncured insulating sheet is less than 10 MPa, the self-supporting property of the uncured insulating sheet at room temperature is remarkably lowered, and the handling property of the uncured insulating sheet is degraded. Sometimes. If the bending elastic modulus at 25 ° C. of the uncured insulating sheet exceeds 1,000 MPa, the insulating cured sheet may not sufficiently adhere to the object to be bonded because the elastic modulus is not sufficiently lowered during heat bonding. And the adhesiveness of an insulation hardening sheet and an adhesion target object may fall.

  When the insulating sheet is cured, the flexural modulus at 25 ° C. of the insulating cured sheet is preferably in the range of 1,000 to 50,000 MPa, and is in the range of 5,000 to 30,000 MPa. It is more preferable. When the bending elastic modulus at 25 ° C. of the insulating cured sheet is too low, for example, when using an insulating sheet to produce a laminated body such as a thin laminated board or a laminated board provided with copper circuits on both sides, The laminate is easy to bend. For this reason, a laminated body becomes easy to be damaged by bending, bending, etc. When the bending elastic modulus at 25 ° C. of the insulating cured sheet is too high, the insulating cured sheet becomes too hard and brittle, and the insulating cured sheet may be easily cracked.

  The bending elastic modulus is, for example, a universal tester RTC-1310A (made by Orientec Co., Ltd.), based on JIS K 7111, using a test piece having a length of 8 cm, a width of 1 cm and a thickness of 4 mm, and the distance between fulcrums. It can be measured under conditions of 6 cm and a speed of 1.5 mm / min. Moreover, when measuring the bending elastic modulus of an insulation hardening sheet, an insulation hardening sheet is obtained by making it harden | cure by the temperature of two steps of 120 degreeC for 1 hour and then 200 degreeC for 1 hour.

  In the insulating sheet according to the present invention, the tan δ of the uncured insulating sheet at 25 ° C. measured using a rotary dynamic viscoelasticity measuring device is in the range of 0.1 to 1.0 and It is preferable that the maximum value of tan δ of the insulating sheet when the cured insulating sheet is heated from 25 ° C. to 250 ° C. is in the range of 1.0 to 5.0. The tan δ of the insulating sheet is more preferably in the range of 0.1 to 0.5. The maximum value of tan δ of the insulating sheet is more preferably in the range of 1.5 to 4.0.

  When the tan δ of the uncured insulating sheet at 25 ° C. is less than 0.1, the flexibility of the uncured insulating sheet is lowered, and the uncured insulating sheet is easily damaged. When the tan δ of the uncured insulating sheet at 25 ° C. is 1.0 or more, the uncured insulating sheet may be too soft, and the handleability of the uncured insulating sheet may be reduced. When the maximum value of tan δ of the insulating sheet when the uncured insulating sheet is heated from 25 ° C. to 250 ° C. is less than 1.0, the insulating sheet does not sufficiently adhere to the object to be bonded during heat bonding Sometimes. When the maximum value of tan δ of the insulating sheet exceeds 5.0, the fluidity of the insulating sheet is too high, and the thickness of the insulating sheet becomes thin at the time of heat bonding, and desired dielectric breakdown characteristics may not be obtained. The tan δ of the uncured insulating sheet at 25 ° C. is a disk-shaped uncured insulating sheet having a diameter of 2 cm, using a rotary dynamic viscoelasticity measuring device VAR-100 (manufactured by Rheologicala Instruments). Can be measured at 25 ° C. with an oscillation strain control mode, a starting stress of 10 Pa, a frequency of 1 Hz, and a strain of 1% using a parallel plate having a diameter of 2 cm. In addition, the maximum value of tan δ of the insulating sheet when the uncured insulating sheet is heated from 25 ° C. to 250 ° C. is obtained by adding the uncured insulating sheet to the measurement conditions described above, and the heating rate is 30 ° C. It can be measured by raising the temperature from 25 ° C. to 250 ° C./min. When the flexural modulus and tan δ are within the specific ranges, the handleability of the uncured insulating sheet is significantly enhanced during manufacturing and use. Further, the adhesive strength such as the insulating sheet and the copper foil is remarkably increased. Moreover, the followability with respect to unevenness | corrugations of an inner layer circuit etc. can be improved. For this reason, it becomes difficult to form a space | gap in an adhesion | attachment interface, therefore heat dissipation becomes higher.

(Laminated board and multilayer laminated board)
The insulating sheet which concerns on this invention is used suitably in order to form the insulating layer of a laminated board and a multilayer laminated board.

  In FIG. 1, the laminated board using the insulating sheet which concerns on one Embodiment of this invention is shown.

  A laminated plate 1 shown in FIG. A conductor layer 3 is provided in a partial region of the upper surface 2 a of the substrate 2. An insulating layer 4 is laminated on the upper surface 2 a of the substrate 2 so as to cover the conductor layer 3. A conductor layer 5 is provided in a partial region of the upper surface 4 a of the insulating layer 4. Therefore, the laminated board 1 includes an insulating layer 4 and conductor layers 3 and 5 laminated on both surfaces of the insulating layer 4. The conductor layer 3 and the conductor layer 5 are connected by a via hole connection (not shown).

  In the laminated board 1, the insulating layer 4 is formed of an insulating cured sheet obtained by curing the insulating sheet according to one embodiment of the present invention. Therefore, even if heat is generated by the conductor layers 3 and 5, the heat can be efficiently dissipated by the insulating layer 4.

  In the multilayer laminate 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. A conductor layer 16 is provided in a partial region of the upper surface 12 a of the substrate 12. Conductive layers 17 and 18 are provided in partial regions of the upper surfaces 13a and 14a of the insulating layers 13 and 14 other than the uppermost insulating layer 15, respectively. Therefore, the multilayer laminate 11 includes a plurality of laminated insulating layers 13 to 15, a conductive layer 17 disposed between the insulating layers 13 and 14, and a conductive layer 18 disposed between the insulating layers 14 and 15. Prepare. The conductor layers 16 to 18 are connected by via hole connection (not shown).

  In the multilayer laminated board 11, the insulating layers 13-15 are formed of the insulation hardening sheet which hardened the insulating sheet which concerns on one Embodiment of this invention. Therefore, even if heat is generated by the conductor layers 16-18, the heat can be efficiently dissipated by the insulating layers 13-15.

  Further, since the insulating layer 4 and the insulating layers 13 to 15 are formed of an insulating cured sheet obtained by curing the insulating sheet, the adhesive strength between the insulating layer 4 and the conductor layers 3 and 5 and the insulating layers 13 to 15 Adhesive strength with the conductor layers 16 to 18 can be increased. Therefore, the loss of electric signals at the interface between the insulating layer 4 and the conductor layers 3 and 5 and at the interface between the insulating layers 13 to 15 and the conductor layers 16 to 18 can be reduced.

  In the case where the insulating layer is formed of an insulating cured sheet obtained by curing the insulating sheet configured according to the present invention, sufficient adhesion strength between the insulating layer and the conductor layer can be obtained without roughening the insulating layer. Can be high. However, the insulating layer may be roughened. By the roughening treatment, finer holes can be formed on the surface of the insulating layer. Therefore, fine wiring can be formed on the surface of the insulating layer, and the signal transmission speed in the wiring can be increased.

  The conductor layer is preferably a wiring circuit. In the case of a wiring circuit, since the adhesive strength between the insulating layer and the conductor layer can be increased, the reliability of the circuit can be increased.

  As a material for forming the conductor layer, a metal foil or metal plating, or a plating material used for circuit protection can be used. The conductor layer is preferably formed by plating. The conductor layer is preferably a plating layer. When the conductor layer is a plating layer formed by plating, the adhesive strength between the insulating layer and the conductor layer can be sufficiently increased.

  Examples of the plating material include gold, silver, copper, rhodium, palladium, nickel, and tin. Two or more kinds of these alloys may be used. Especially, it is preferable that a conductor layer is a copper layer, and it is more preferable that it is a copper plating layer.

  Before forming the conductor layer, the surface of the insulating layer may be roughened with a roughening solution in order to form fine irregularities on the surface of the insulating layer. It is preferable that at least a part of the surface of the insulating layer is roughened with a roughening solution, and a conductor layer is formed on the roughened surface by plating.

  It is preferable to swell before the roughening treatment. However, the swelling treatment is not necessarily performed.

  As the swelling treatment method, for example, a method of treating the surface of the insulating layer with an aqueous solution or an organic solvent dispersion solution of a compound mainly composed of ethylene glycol or the like is used. For the swelling treatment, a 40% by weight ethylene glycol aqueous solution is suitably used.

  For the roughening treatment, for example, a roughening solution such as a chemical oxidizing agent such as a manganese compound, a chromium compound, or a persulfuric acid compound is used. These chemical oxidizing agents are used as an aqueous solution or an organic solvent dispersion after, for example, water or an organic solvent is added.

  Examples of the manganese compound include potassium permanganate and sodium permanganate. Examples of the chromium compound include potassium dichromate and anhydrous potassium chromate. Examples of the persulfate compound include sodium persulfate, potassium persulfate, and ammonium persulfate.

  The roughening treatment method is not particularly limited. For the roughening treatment, for example, 30 to 90 g / L permanganic acid or permanganate solution or 30 to 90 g / L sodium hydroxide solution is preferably used.

(Laminated structure)
The insulating sheet according to the present invention is also used for bonding a heat conductor having a thermal conductivity of 10 W / m · K or more to a conductive layer.

  In FIG. 3, the laminated structure using the insulating sheet which concerns on one Embodiment of this invention is shown.

  The laminated structure 21 shown in FIG. 3 is opposite to the heat conductor 22, the insulating layer 23 laminated on one surface 22a of the heat conductor 22, and the surface of the insulating layer 23 on which the heat conductor 22 is laminated. And a conductive layer 24 laminated on the side surface. The insulating layer 23 is formed of an insulating cured sheet obtained by curing the insulating sheet according to one embodiment of the present invention. The thermal conductivity of the thermal conductor 22 is 10 W / m · K or more.

  It is sufficient that the insulating layer 23 and the conductive layer 24 are laminated in this order on at least one surface 22a of the heat conductor 22, and the insulating layer and the conductive layer are also formed on the other surface 22b of the heat conductor 22. You may laminate | stack in order.

  In the laminated structure 21, since the insulating layer 23 has a high thermal conductivity, heat from the conductive layer 24 side is easily transmitted to the thermal conductor 22 through the insulating layer 23. In the laminated structure 21, heat can be efficiently dissipated by the heat conductor 22.

  The heat conductor having the heat conductivity of 10 W / m · K or more is not particularly limited. Examples of the heat conductor having a thermal conductivity of 10 W / m · K or more include aluminum, copper, alumina, beryllia, silicon carbide, silicon nitride, aluminum nitride, and a graphite sheet. Especially, it is preferable that the heat conductor whose said heat conductivity is 10 W / m * K or more is copper or aluminum. Copper or aluminum is excellent in heat dissipation.

  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) Bisphenol A-type phenoxy resin (trade name: E1256, Mw = 51,000, Tg = 98 ° C., manufactured by Japan Epoxy Resin Co., Ltd.)
(2) High heat resistance phenoxy resin (manufactured by Toto Kasei Co., Ltd., trade name: FX-293, Mw = 43,700, Tg = 163 ° C.)
(3) Epoxy group-containing styrene resin (manufactured by NOF Corporation, trade name: Marproof G-1010S, Mw = 100,000, Tg = 93 ° C.)

[Epoxy resin (B1)]
(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 (Dainippon Ink Chemical Co., Ltd., trade name: EPICLON HP-4032D, Mw = 304)
(6) Bisphenol A type solid epoxy resin (manufactured by Japan Epoxy Resin Co., Ltd., trade name: 1003, Mw = 1,300)
(7) Epoxy group-containing acrylic resin (manufactured by NOF Corporation, trade name: Marproof G-013S, Mw = 9,000, Tg = 69 ° C.)

[Oxetane resin (B2)]
(1) Oxetane resin containing benzene skeleton (manufactured by Ube Industries, trade name: etanacol OXTP, Mw = 362.4)

[Curing agent (C)]
(1) Alicyclic skeleton acid anhydride (manufactured by Shin Nippon Chemical Co., Ltd., trade name: MH-700)
(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 (acid anhydride represented by the above formula (1))
(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) Triazine skeleton phenolic resin (Dainippon Ink Chemical Co., Ltd., trade name: Phenolite KA-7052-L2)
(8) Melamine skeleton phenolic resin (manufactured by Gunei Chemical Industry Co., Ltd., trade name: PS-6492)
(9) Isocyanur-modified solid dispersion type imidazole (imidazole curing accelerator, manufactured by Shikoku Kasei Co., Ltd., trade name: 2MZA-PW)

[Filler (D)]
(1) Crushed alumina 1 (manufactured by Nippon Light Metal Co., Ltd., trade name: LS-242C, average particle diameter 2 μm)
(2) Crushed alumina 2 (Nippon Light Metal Co., Ltd., trade name: LS-250, average particle size 0.6 μm)
(3) Plate-form boron nitride (manufactured by Showa Denko KK, trade name: UHP-S1, average major axis 1 μm)
(4) Aluminum nitride (trade name: TOYALNITE-Super JA, average particle size 0.8 μm, manufactured by Toyo Aluminum Co., Ltd.)
(5) Crystalline silica (manufactured by Tatsumori Co., Ltd., trade name: Crystallite CMC-12, average particle size 5 μm)
(6) Synthetic magnesite (Kamishima Chemical Co., Ltd., trade name: MSS, average particle size 1 μm)
(7) Plate-like alumina (manufactured by Kinsei Matec Co., Ltd., trade name: Seraph 02025, average major axis 2 μm, aspect ratio 20-30)

[Fillers other than filler (D)]
(1) Spherical alumina (manufactured by Denki Kagaku Kogyo Co., Ltd., trade name: DAM-45, average particle size 45 μm)

[Resin particles (E)]
(1) 0.1 μm particles (core-shell type silicone-acrylic particles, manufactured by Asahi Kasei Wacker Silicone Co., Ltd., trade name: P22, average particle size 0.1 μm, having a core-shell structure, a skeleton in which oxygen atoms are directly bonded to silicon atoms (Including core layer containing compound and organic matter)

[Dispersant (F)]
(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)
(2) Mica (manufactured by Yamaguchi Mica Industry Co., Ltd., trade name: SJ005, average particle size 5 μm)
(3) Talc (Nippon Talc Co., Ltd., trade name: K-1, average particle size 8 μm)
(4) Aluminum hydroxide (manufactured by Nippon Light Metal Co., Ltd., trade name: B-103, average particle size 8 μm)
(5) Magnesium hydroxide (manufactured by Tateho Chemical Industry Co., Ltd., trade name: PZ-1, average particle size 1.2 μm)

[solvent]
(1) Methyl ethyl ketone

(Examples 1-34 and Comparative Examples 1-4)
Using a homodisper type stirrer, each raw material was blended in the proportions shown in Tables 1 to 5 below (the 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 flat shape of 460 mm x 610 mm to obtain a test sample. Using the obtained test sample, the handling property when the uncured insulating sheet was peeled from the PET sheet at room temperature (23 ° C.) was determined according to the following criteria.

[Handling criteria]
◯: Insulation sheet is not deformed and can be easily peeled Δ: Insulation sheet can be peeled, but sheet elongation or breakage occurs ×: Insulation sheet cannot be peeled (2) Glass transition temperature Differential scanning calorimeter “DSC220C” The glass transition temperature of the uncured insulating sheet was measured at a rate of temperature increase of 3 ° C./min using (Seiko Instruments Inc.).

(3) Arithmetic mean roughness Ra
The arithmetic average roughness Ra of the insulating sheet was measured according to JIS B 0601: 2001 using model SURFCOM 1400D manufactured by Tokyo Seimitsu. Measurement conditions were as follows.

Cut-off value: 0.8mm
Evaluation length: 4mm
Measurement speed: 0.3 mm / s
Tip radius of stylus: R 2 μm

(4) Thermal conductivity The insulating sheet was heated in an oven at 120 ° C. for 1 hour and then in an oven at 200 ° C. for 1 hour to cure the insulating sheet. The thermal conductivity of the insulating cured sheet was measured using a thermal conductivity meter “rapid thermal conductivity meter QTM-500” manufactured by Kyoto Electronics Industry Co., Ltd.

(5) Dielectric breakdown voltage The insulation sheet was cut out into a planar shape 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 an insulating cured sheet. Using a withstand voltage tester (MODEL7473, manufactured by EXTECH Electronics), an AC voltage was applied between the insulating cured sheets so that the voltage increased at a rate of 1 kV / sec. The voltage at which the insulation cured sheet was broken was defined as the dielectric breakdown voltage.

(6) Solder heat resistance test The inner layer circuit board was produced using the glass epoxy double-sided copper clad laminated board in which the 35-micrometer-thick copper foil was laminated | stacked on both surfaces. A laminated sheet having a PET sheet and an insulating sheet formed on the PET sheet is formed from the insulating sheet side on the inner circuit board by a vacuum laminator under conditions of a temperature of 100 ° C., 9.8 N / cm ² and an atmospheric pressure of 5 mmHg or less Laminated on both sides. Next, the release PET sheet was peeled off. It heated at 200 degreeC for 60 minutes, the insulating sheet was hardened, and the insulating layer was formed. After that, holes for via holes were made with a laser. The surface of the insulating layer was roughened with an alkaline oxidizer of permanganate (Atotech Japan Co., Ltd.), then electrolessly and electroplated, and a four-layer printed wiring board was obtained according to the subtractive method. Further, annealing was performed by heating at 200 ° C. for 30 minutes. The annealed printed wiring board was floated in a 300 ° C. solder bath with the copper foil side facing down, the time until the copper foil swelled or peeled off was measured, and the following criteria were used.

[Criteria for solder heat resistance test]
◎: Swelling and peeling do not occur even after 10 minutes 〇: Swelling or peeling occurs after 3 minutes and before 10 minutes △: Swelling or peeling after 1 minute and before 3 minutes have passed Generation ×: Swelling or peeling occurs before 1 minute elapses

(7) Adhesive strength (stripping strength)
An inner-layer circuit board was produced using a glass epoxy double-sided copper-clad laminate in which a 35 μm thick copper foil was laminated on both sides. A laminated sheet having a PET sheet and an insulating sheet formed on the PET sheet is formed from the insulating sheet side on the inner circuit board by a vacuum laminator under conditions of a temperature of 100 ° C., 9.8 N / cm ² and an atmospheric pressure of 5 mmHg or less Laminated on both sides. Next, the release PET sheet was peeled off. It heated at 200 degreeC for 60 minutes, the insulating sheet was hardened, and the insulating layer was formed. Thereafter, the surface of the insulating layer was roughened with an alkaline oxidizer of permanganate (Atotech Japan Co., Ltd.), and then a conductor layer band having a width of 10 mm was formed by electroless and electrolytic plating. Next, annealing was performed by heating at 200 ° C. for 30 minutes to obtain a laminate of an insulating layer and a conductor layer. The peel strength of the conductor layer of the obtained laminate was measured with respect to the cured product at an angle of 90 ° C. and a pulling speed of 50 mm / min.

(8) Workability 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 maintained at a pressure of 4 MPa with a vacuum press machine at 120 ° C. for 1 hour, and further at 200 ° C. The insulating sheet was press cured for a time to form a copper-clad laminate. The obtained copper-clad laminate was router-processed using a drill with a diameter of 2.0 mm (Union Tool, RA series) under conditions of a rotation speed of 30000 and a table feed speed of 0.5 m / min. The processing distance until the flash was generated was measured, and the workability was evaluated according to the following criteria.

[Criteria for workability]
○: Can be processed 5 m or more without burring △: Can be processed 1 m or more but less than 5 m without burring × Burr is generated by processing less than 1 m

(9) Extrusion amount at the time of laminating press After a laminated sheet having a PET sheet and an insulating sheet formed on the PET sheet was cut into a 13 cm × 5 cm planar shape, the insulating sheet was peeled from the PET sheet. Also, a 13 cm × 5 cm flat aluminum plate (Engineering Test Service, JIS H4000 A5052P, maximum height roughness Rz = 1.1) and a 13 cm × 5 cm flat copper foil (Fukuda Metal Foil Powder Industry) Made by the company, electrolytic copper foil, CT-T8).

  After a laminated body was obtained by sandwiching an insulating sheet between the rough surface of the aluminum plate and the rough surface of the copper foil, the laminate was heated and pressed at a temperature of 120 ° C. and a pressure of 4 MPa for 10 minutes. The weight of the insulating sheet which protruded from the side surface of the laminated body after pressing was measured, and the amount of protrusion of the insulating sheet was determined by the following formula. The amount of protrusion was determined according to the following criteria.

  Amount of protrusion = (weight of insulating sheet protruding from side surface of laminate after pressing) / (weight of insulating sheet before pressing) × 100

[Criteria for protruding amount during laminating press]
○: The amount of protrusion of the insulating sheet is less than 7% △: The amount of protrusion of the insulating sheet is more than 7% and less than 10% ×: The amount of protrusion of the insulating sheet is 10% or more

(10) Self-supporting property In the evaluation of the above (1) handling properties, an uncured insulating sheet after being peeled from the PET sheet was prepared. The square of the uncured insulating sheet was fixed, and the insulating sheet was suspended in the air so that the square was positioned in a direction parallel to the horizontal direction, and left at 23 ° C. for 10 minutes. The deformation of the insulating sheet after being left was observed, and the self-supporting property was determined according to the following criteria.

[Independence criteria]
○: The insulation sheet is bent downward, and the insulation sheet is bent in the vertical direction (degree of deformation) within 5 cm. Δ: The insulation sheet is bent downward, and the insulation sheet is bent in the vertical direction ( Deformation degree) exceeds 5 cm ×: The insulating sheet was torn

(11) Heat dissipation Insulation sheet is sandwiched between an aluminum plate with a thickness of 1 mm and an electrolytic copper foil with a thickness of 35 μm. The sheet was press cured to form a copper clad laminate. The copper foil surface of the obtained copper-clad laminate was pressed against a heating element with a smooth surface controlled to 60 ° C. of the same size at a pressure of 196 N / cm ² . The temperature of the surface of the aluminum plate was measured with a thermocouple, and the heat dissipation was determined according to the following criteria.

[Criteria for heat dissipation]
A: Temperature difference between the heating element and the aluminum plate surface is 3 ° C or less. ○: Temperature difference between the heating element and the aluminum plate surface exceeds 3 ° C and less than 6 ° C. Δ: Temperature difference between the heating element and the aluminum plate surface. Exceeding 6 ° C. and 10 ° C. or less ×: Temperature difference between the surface of the aluminum plate and the heating element exceeds 10 ° C.

(12) Flexural modulus Using a universal testing machine RTC-1310A (manufactured by Orientec Co., Ltd.), a test piece having a length of 8 cm, a width of 1 cm and a thickness of 4 mm in accordance with JIS K7111, a fulcrum distance of 6 cm and a speed of 1. By measuring under each condition of 5 mm / min, the flexural modulus at 25 ° C. of the uncured insulating sheet was measured.

  The insulating sheet was cured at 120 ° C. for 1 hour and then at 200 ° C. for 1 hour to obtain an insulating cured sheet. Using a universal testing machine (made by Orientec Co., Ltd.) in the same manner as the uncured insulating sheet, a test piece having a length of 8 cm, a width of 1 cm and a thickness of 4 mm was obtained from a fulcrum distance of 6 cm and a speed of 1 according to JIS K 7111. The bending elastic modulus at 25 ° C. of the obtained insulating cured sheet was measured by measuring under each condition of 0.5 mm / min.

(13) Modulus of elasticity Using a rotary dynamic viscoelasticity measuring device VAR-100 (manufactured by Rheologicala Instruments Co., Ltd.), using a disk-shaped uncured insulating sheet sample with a diameter of 2 cm, a parallel type with a diameter of 2 cm Using the plate, the tan δ at 25 ° C. of the uncured insulating sheet was measured under the conditions of the oscillation strain control mode, the starting stress of 10 Pa, the frequency of 1 Hz, and the strain of 1%. In addition, the maximum value of tan δ of the insulating sheet when the uncured insulating sheet is heated from 25 ° C. to 250 ° C. is obtained by adding the uncured insulating sheet sample to the above measurement conditions and increasing the heating rate 30 It was measured by raising the temperature from 25 ° C. to 250 ° C. at a rate of ° C./min.

(14) Reaction rate Using a differential scanning calorimeter “DSC220C” manufactured by Seiko Instruments Inc., the obtained insulating sheet was heated to 120 ° C. at a measurement start temperature of 30 ° C. and a heating rate of 8 ° C./min. After holding for 1 hour, the temperature was further raised to 200 ° C. at a heating rate of 8 ° C./min and held for 1 hour. The amount of heat generated when the insulating sheet was cured in these two stages (hereinafter referred to as heat amount A) was measured.

  Next, on the release PET sheet having a thickness of 50 μm, the insulating material prepared in the preparation of the insulating sheets of Examples and Comparative Examples was applied so as to have a thickness of 50 μm. An uncured insulating sheet dried without heating was prepared in the same manner as in the examples and comparative examples except that it was dried for 1 hour. Similarly to the measurement of the amount of heat A, the amount of heat generated when cured in two stages (hereinafter referred to as the amount of heat B) was measured. From the obtained heat quantity A and heat quantity B, the reaction rate of the uncured insulating sheet was determined by the following formula.

Reaction rate (%) = [1- (heat amount A / heat amount B)] × 100
The results are shown in Tables 1 to 5 below.

DESCRIPTION OF SYMBOLS 1 ... Laminated board 2 ... Board | substrate 2a ... Upper surface 3 ... Conductor layer 4 ... Insulating layer 4a ... Upper surface 5 ... Conductor layer 11 ... Multilayer laminated board 12 ... Substrate 12a ... Upper surface 13-15 ... Insulating layer 13a, 14a ... Upper surface 16-18 ... Conductor layer 21 ... Laminated structure 22 ... Thermal conductor 22a ... One side 22b ... The other side 23 ... Insulating layer 24 ... Conductive layer

Claims (16)

The arithmetic average roughness Ra of the surface is 0.1 μm or more and 3 μm or less,
At least one of a polymer (A) having a weight average molecular weight of 10,000 or more, an epoxy resin (B1) having a weight average molecular weight of less than 10,000, and an oxetane resin (B2) having a weight average molecular weight of less than 10,000 A resin (B), a curing agent (C), and a filler (D) having an average particle diameter in the range of 0.1 to 5 μm,
The insulating sheet whose content of the said filler (D) in 100 volume% of insulating sheets exists in the range of 20-90 volume%.   The filler (D) is at least one selected from the group consisting of alumina, crystalline silica, synthetic magnesite, boron nitride, aluminum nitride, silicon nitride, silicon carbide, zinc oxide and magnesium oxide. The insulation sheet as described in 2.   The insulating sheet according to claim 1 or 2, wherein the filler (D) has a crushed shape, a substantially polyhedral shape or a plate shape.   The curing agent (C) is 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. The insulation sheet of any one of Claims.   The insulating sheet according to claim 4, wherein the curing agent (C) is a phenol resin having a melamine skeleton or a triazine skeleton, or a phenol resin having an allyl group.   The curing agent (C) is obtained by an addition reaction of an acid anhydride having a polyalicyclic skeleton, a water addition of the acid anhydride or a modification of the acid anhydride, or a terpene compound and maleic anhydride. The insulating sheet according to claim 4, which is an acid anhydride having an alicyclic skeleton, a water additive of the acid anhydride, or a modified product of the acid anhydride. The insulating sheet according to claim 6, wherein the curing agent (C) is an acid anhydride represented by any of the following formulas (1) to (3).

In said formula (3), R1 and R2 show hydrogen, a C1-C5 alkyl group, or a hydroxyl group, respectively.   The insulating sheet according to any one of claims 1 to 7, wherein the insulating sheet further includes resin particles (E).   The insulating sheet according to any one of claims 1 to 8, wherein the polymer (A) is a polymer having an aromatic skeleton and having a weight average molecular weight of 30,000 or more.   The insulating sheet according to any one of claims 1 to 9, wherein the polymer (A) is a phenoxy resin.   The insulating sheet according to claim 10, wherein the glass transition temperature of the phenoxy resin is 95 ° C or higher.   The resin (B) has an aromatic skeleton and an epoxy monomer (B1b) having a weight average molecular weight of 600 or less and an oxetane monomer (B2b) having an aromatic skeleton and a weight average molecular weight of 600 or less. The insulating sheet according to any one of claims 1 to 11, comprising at least one of the monomers.   The content of the polymer (A) is 20 to 60% by weight in a total of 100% by weight of the resin components in the insulating sheet containing the polymer (A), the resin (B), and the curing agent (C). The content of the resin (B) is 10 to 60% by weight, and the total content of the polymer (A) and the resin (B) is less than 100% by weight. The insulating sheet according to item 1. An insulating layer, and a conductor layer laminated on at least one surface of the insulating layer,
The laminated board in which the said insulating layer is formed with the insulation hardening sheet which hardened the insulating sheet of any one of Claims 1-13. A plurality of laminated insulating layers, and a conductor layer disposed between the plurality of insulating layers,
The multilayer laminated board in which the said insulating layer is formed with the insulation hardening sheet which hardened the insulating sheet of any one of Claims 1-13.   The multilayer laminate according to claim 15, wherein the conductor layer is formed by plating.

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