Epoxy resin composition for interlayer insulation, resin sheet for interlayer insulation, laminate for circuit board, metal base circuit board, and power module

Abstract

Provided are an epoxy resin composition for interlayer insulation, a resin sheet for interlayer insulation, a laminate for circuit boards, a metal base circuit board, and a power module, which have excellent adhesion and heat resistance and are capable of highly maintaining good withstand voltage. An epoxy resin composition for interlayer insulation according to an embodiment of the present invention contains an epoxy resin, an epoxy-modified polybutadiene compound, and an aromatic amine compound, the epoxy-modified polybutadiene compound containing a repeating unit represented by general formula (I), a repeating unit represented by general formula (II), and a repeating unit represented by general formula (III), and at least one of a repeating unit represented by general formula (i), a repeating unit represented by general formula (ii), and a repeating unit represented by general formula (iii). # imgabs0 #

Description

Technical Field

[0001] The present invention relates to an epoxy resin composition for interlayer insulation, a resin sheet for interlayer insulation, a laminate for circuit substrates, a metal base circuit substrate, and a power module. Background Art

[0002] In recent years, electronic technology has developed significantly, and the performance and miniaturization of electrical and electronic equipment have been rapidly developing. Along with this, metal base circuit boards used in this field corresponding to high-density actual mounting have been developed to be more compact and high-density than before. Therefore, various performance improvements are also required for metal base circuit boards, and a wide range of measures have been taken to meet these requirements.

[0003] As a resin composition for forming an insulating layer of a metal base circuit board, a resin composition using an epoxy resin has been widely used. For example, Patent Document 1 discloses a resin composition in which a specific phenolic curing agent, a phenoxy resin and rubber particles are added to a composition containing an epoxy resin, and the resin composition is a resin composition that can provide an insulating layer with high interface adhesion strength with a plated conductor layer despite a small surface roughness of the insulating layer.

[0004] In addition, Patent Document 2 discloses a printed circuit board having an insulating layer having excellent characteristics of both resin components by adjusting the average domain size of the island phase and the blending ratio of the epoxy-modified acrylic rubber and the epoxy resin in an insulating layer having a phase separation structure composed of a sea phase of epoxy-modified acrylic rubber and an island phase of epoxy resin.

[0005] Epoxy resin compositions are also widely used as sealing materials in electronic component devices, and various improvements have been made to meet the performance required of sealing materials. For example, Patent Document 3 discloses a solvent-free epoxy resin composition containing a liquid epoxy resin, a liquid aromatic amine curing agent, an epoxidized polybutadiene compound, and an inorganic filler, which is a sealing epoxy resin composition with excellent adhesion under high temperature and high humidity. Here, as the epoxidized polybutadiene compound, an epoxidized butadiene rubber composed of a vinyl-1,2 bond repeating unit derived from butadiene and a 1,2 bond repeating unit formed by epoxidation of the repeating unit is used.

[0006] On the other hand, the thermal conductivity of resin is low, so research on adding inorganic fillers to the insulating layer in metal-based circuit boards to improve the thermal conductivity of the insulating layer is also being widely promoted. For example, Patent Document 4 discloses that boron nitride and aluminum oxide are added as inorganic fillers to the insulating layer to improve thermal conductivity, and in order to improve the adhesion strength between the metal foil and the insulating layer, the proportion of boron nitride in the inorganic filler is limited to less than 35% by volume. Prior art literature Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2007-254709 Patent Document 2: Japanese Patent Application Publication No. 2016-79367 Patent Document 3: Japanese Patent Application Publication No. 2007-254709 Patent Document 4: Japanese Patent Application Publication No. 2013-91179 Summary of the invention Technical problem to be solved by the invention

[0008] Metal-based circuit boards require heat resistance that can withstand solder reflow treatment when components are actually installed. Therefore, the interlayer insulation epoxy resin composition used for the insulating layer of the metal-based circuit board requires better heat resistance than the sealing epoxy resin composition used for the sealing component. In addition, with the increase in solder reflow temperature in recent years, the heat resistance requirements for metal-based circuit boards are becoming more and more stringent, so it is required to further improve the heat resistance and voltage resistance of the insulating layer of the metal-based circuit board.

[0009] An object of the present invention is to provide an interlayer insulating epoxy resin composition having excellent adhesion and heat resistance and maintaining good withstand voltage even after solder reflow treatment, for example, an interlayer insulating resin sheet, a circuit board laminate, a metal base circuit board, and a power module. Solutions to technical problems

[0010] According to a first aspect of the present invention, there is provided an epoxy resin composition for interlayer insulation, comprising: an epoxy resin, an epoxy-modified polybutadiene compound and an aromatic amine compound, wherein the epoxy-modified polybutadiene compound comprises a repeating unit represented by the following general formula (I), a repeating unit represented by the following general formula (II) and a repeating unit represented by the following general formula (III), and comprises at least one of a repeating unit represented by the following general formula (i), a repeating unit represented by the following general formula (ii) and a repeating unit represented by the following general formula (iii).

[0011] [Chemistry 1]

[0012] The interlayer insulating epoxy resin composition of the present embodiment contains at least bisphenol A type diglycidyl ether as the epoxy resin.

[0013] In the interlayer insulation epoxy resin composition of the present embodiment, the aromatic amine compound includes a compound represented by the following general formula (IV).

[0014] [Chemistry 2]

[0015] In the general formula (IV), R1 represents an alkyl group, m represents an integer greater than 2, and n represents an integer greater than 0, and m and n satisfy m+n≤6. When n is greater than 2, the plurality of R1s present may be the same as or different from each other.

[0016] Furthermore, the interlayer insulating epoxy resin composition of the present embodiment contains a boron-phosphorus complex represented by the following general formula (V) and a phosphorus compound represented by the following general formula (VI).

[0017] [Chemistry 3]

[0018] In the general formula (V), R2 and R3 each independently represent an alkyl group, r represents an integer from 0 to 5, and s represents an integer from 0 to 5. When r is an integer from 2 to 5, the multiple R2s present may be the same or different from each other, and when s is an integer from 2 to 5, the multiple R3s present may be the same or different from each other.

[0019] [Chemistry 4]

[0020] In the general formula (VI), R4 represents an alkyl group or an alkoxy group, and t represents an integer of 0 to 5. When t is an integer of 2 or more, a plurality of R4s present may be the same as or different from each other.

[0021] Furthermore, the interlayer insulating epoxy resin composition of the present embodiment may contain an inorganic filler.

[0022] According to a second aspect of the present invention, there is provided an interlayer insulating resin sheet comprising a cured product of the interlayer insulating epoxy resin composition and having a phase separation structure in which a discontinuous phase containing the epoxy-modified polybutadiene compound is dispersed in a continuous phase containing the epoxy resin.

[0023] In the interlayer insulation resin sheet of the present embodiment, the first glass transition temperature Tg1 derived from the epoxy-modified polybutadiene compound is -5°C or lower, and the second glass transition temperature Tg2 derived from the epoxy resin is 175°C or higher.

[0024] According to a third aspect of the present invention, there is provided a laminate for a circuit substrate, comprising a metal substrate, an insulating layer provided on at least one surface of the metal substrate, and a metal foil provided on the insulating layer, wherein the insulating layer is the above-mentioned interlayer insulating resin sheet.

[0025] According to a fourth aspect of the present invention, a metal-based circuit substrate is provided, which is a laminate for a circuit substrate comprising a metal substrate, an insulating layer provided on at least one surface of the metal substrate, and a circuit pattern provided on the insulating layer, wherein the insulating layer is the above-mentioned interlayer insulating resin sheet.

[0026] According to a fifth aspect of the present invention, there is provided a power module comprising the metal base circuit substrate. Effects of the Invention

[0027] According to the present invention, there are provided an interlayer insulating epoxy resin composition having excellent adhesion and heat resistance and maintaining good withstand voltage even after solder reflow treatment, for example, an interlayer insulating resin sheet, a circuit board laminate, a metal base circuit board, and a power module. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Graphs showing the behaviors of the storage modulus (E'), loss modulus (E"), and loss tangent (tan δ) of the interlayer insulating grease sheet according to one embodiment of the present invention. Figure 2 This is an image of a fracture surface photograph of a cured product of the interlayer insulating epoxy resin composition according to one embodiment of the present invention. Figure 3 This is an image of a fracture surface photograph of a cured product of a comparative epoxy resin composition using an epoxy-modified polybutadiene having no 1,4-bond repeating unit. Figure 4 This is a perspective view schematically showing a laminate for a circuit board according to one embodiment of the present invention. Figure 5 yes Figure 2 The laminated body for a circuit board shown is a cross-sectional view taken along line II-II. Figure 6 This is a cross-sectional view schematically showing a metal base circuit board according to one embodiment of the present invention. Figure 7 It is a cross-sectional view schematically showing a power module according to one embodiment of the present invention. Figure 8 is a cross-sectional view schematically showing a conventional power module. DETAILED DESCRIPTION

[0029] Hereinafter, the embodiments of the present invention are described in the order of an epoxy resin composition for interlayer insulation as a first embodiment, a resin sheet for interlayer insulation as a second embodiment, a laminate for circuit substrate as a third embodiment, a metal base circuit substrate as a fourth embodiment, and a power module as a fifth embodiment. These embodiments are more specific embodiments of any of the above aspects. In addition, the following includes descriptions with reference to the accompanying drawings, but the elements with the same or similar functions in the drawings referred to herein are marked with the same reference numerals, and repeated descriptions are omitted. In addition, in each of the drawings, the size ratio or shape may be different from the actual object.

[0030] <Epoxy resin composition for interlayer insulation> The epoxy resin composition for interlayer insulation according to the first embodiment (hereinafter also referred to as “epoxy resin composition”) contains an epoxy resin, an epoxy-modified polybutadiene compound, and an aromatic amine compound.

[0031] (Epoxy resin) As the epoxy resin, one or two or more known epoxy resins can be used. Examples of epoxy resins include: bisphenol epoxy resins, phenol novolac epoxy resins, o-cresol novolac epoxy resins, biphenyl epoxy resins, dicyclopentadiene epoxy resins, diphenylfluorene epoxy resins and their halogen, amino or alkyl substituted products, glycidyl epoxy resins, naphthalene epoxy resins, heterocyclic epoxy resins and other epoxy resins containing aromatic rings / aliphatic rings, isocyanate-modified epoxy resins, diaryl sulfone epoxy resins, hydroquinone epoxy resins, hydantoin epoxy resins, resorcinol diglycidyl ether, triglycidyl p-aminophenol, m-aminophenol triglycidyl ether, tetraglycidyl methylethylenediphenylamine, (trihydroxyphenyl)methane triglycidyl ether, tetraphenylethane tetraglycidyl ether and other epoxy resins (polyepoxides) containing two or more epoxy groups in the molecule.

[0032] Among them, from the perspective of the operability of the curable resin composition, the heat resistance of the cured product, etc., it is preferred to use a bisphenol epoxy resin as the epoxy resin. As specific examples of the bisphenol epoxy resin, bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin, bisphenol AD ​​epoxy resin, etc. can be cited. Among them, from the perspective of the operability of the curable resin composition and the heat resistance of the cured product, bisphenol A epoxy resin is more preferably used, and bisphenol A diglycidyl ether is further preferably used.

[0033] The weight average molecular weight (Mw) of the epoxy resin preferably used in this embodiment is 100 to 10000 according to one example, and 200 to 5000 according to another example. When the weight average molecular weight (Mw) of the epoxy resin is within the above range, it is preferred from the viewpoint of the adhesion and withstand voltage that the resin easily flows during bonding and follows the unevenness, the gap easily falls off, etc. Here, the weight average molecular weight is expressed as a polystyrene conversion value measured by GPC (gel permeation chromatography) method.

[0034] The epoxy equivalent of the epoxy resin preferably used in this embodiment is 50 to 2000 according to one example, and 100 to 1000 according to another example. When the epoxy equivalent of the epoxy resin is within the above range, the time required for curing is shortened and a high Tg can be obtained.

[0035] (Epoxy modified polybutadiene compound) The epoxy-modified polybutadiene compound is an epoxy-modified butadiene rubber obtained by epoxy-modifying a polymer (butadiene rubber) composed of 1,3-butadiene. The butadiene rubber is a polymer formed by addition polymerization of 1,3-butadiene of a conjugated diene monomer. Therefore, the epoxy-modified polybutadiene compound used in the present embodiment (hereinafter sometimes referred to as "epoxy-modified butadiene rubber", etc.) contains repeating units from trans-1,4-bonded butadiene represented by the following general formula (I), repeating units from cis-1,4-bonded butadiene represented by the following general formula (II), and repeating units from vinyl-1,2-bonded butadiene represented by the following general formula (III) in the main chain according to the bonding mode of the monomers.

[0036] [Chemistry 5]

[0037] In the epoxy-modified polybutadiene compound used in the present embodiment, at least one of the repeating units represented by the above-mentioned general formulas (I) to (III) is epoxidized. That is, the epoxy-modified polybutadiene compound of the present embodiment contains at least one of a 1,4-bonded repeating unit represented by the following general formula (i), a 1,4-bonded repeating unit represented by the following general formula (ii), and a 1,2-bonded repeating unit represented by the following general formula (iii) as a repeating unit derived from epoxidized butadiene.

[0038] [Chemistry 6]

[0039] Hereinafter, the repeating units belonging to group A composed of repeating units represented by general formulae (I), (II), (i) and (ii) are referred to as "1,4-bond repeating units", and the repeating units belonging to group B composed of repeating units represented by general formulae (III) and (iii) are referred to as "1,2-bond repeating units".

[0040] [Chemistry 7]

[0041] Compared to the epoxy-modified polybutadiene compound used in Patent Document 3, which is an epoxy-modified butadiene rubber composed of only 1,2 bond repeating units, the epoxy-modified polybutadiene compound used in this embodiment contains 1,4 bond repeating units in addition to 1,2 bond repeating units as described above. That is, the epoxy-modified polybutadiene compound must contain 1,4 bond repeating units represented by general formulas (I) and (II) among the 1,4 bond repeating units belonging to group A, and optionally contains 1,4 bond repeating units represented by general formulas (i) and (ii). As an epoxy-modified butadiene rubber component used in combination with an epoxy resin, the epoxy resin composition of this embodiment containing such an epoxy-modified polybutadiene compound having 1,4 bond repeating units can provide a resin sheet for interlayer insulation having high adhesion and heat resistance and maintaining good voltage resistance after, for example, solder reflow treatment, as described later.

[0042] In the present embodiment, the blending ratio (molar ratio) of the 1,4-bond repeating unit to the 1,2-bond repeating unit contained in the epoxy-modified polybutadiene compound is preferably 5:5 to 0.5:9.5 according to one example, and more preferably 4:6 to 1:9 according to another example.

[0043] The epoxy-modified polybutadiene compound containing 1,4 bond repeating units can use commercial products or compounds manufactured by known methods. The number average molecular weight (Mn) of the epoxy-modified polybutadiene compound preferably used in this embodiment is 500 or more and 10000 or less according to one example, and 1000 or more and 7000 or less according to another example. When the number average molecular weight of the epoxy-modified polybutadiene compound is within the above range, it can be easily dissolved in a solvent to impart appropriate flexibility.

[0044] The epoxy equivalent of the epoxy-modified polybutadiene compound preferably used in the present embodiment is 50 to 500 according to one example, and 100 to 350 according to another example. When the epoxy equivalent of the epoxy-modified polybutadiene compound is within the above range, the adhesion between the epoxy-modified polybutadiene compound and the epoxy resin during phase separation can be appropriately adjusted, which is preferred.

[0045] The blending ratio of the epoxy-modified polybutadiene compound in the epoxy resin composition may be 5 to 40 parts by mass, and 10 to 30 parts by mass, based on 100 parts by mass of the total of the epoxy resin, the aromatic amine compound, and the epoxy-modified polybutadiene compound.

[0046] (Aromatic amine compound) The epoxy resin composition of the present embodiment contains an aromatic amine compound as a curing agent. The aromatic amine compound preferably has two or more amino groups substituted on the aromatic ring, and preferably contains an aromatic amine compound represented by the following general formula (IV).

[0047] [Chemistry 8]

[0048] In the general formula (IV), R1 represents an alkyl group, m represents an integer greater than 2, and n represents an integer greater than 0, and m and n satisfy m+n≤6. When n is an integer greater than 2, a plurality of R1s present may be the same as or different from each other.

[0049] m, which indicates the number of substitutions of the amino group on the benzene ring, is 2 to 6, may be 2 to 5, may be 2 or 3, or may be 2. When m is 2, the two amino groups on the benzene ring are preferably arranged at the meta or ortho position relative to one amino group.

[0050] R1 is any substituent on the benzene ring. The carbon number of the alkyl group represented by R1 may be 1 to 4, or 1 or 2. Specific examples of the alkyl group include methyl, ethyl, propyl, butyl, etc. n, which represents the number of substitutions of R1 on the benzene ring, is 0 to 4, 0 to 3, or 1 to 3.

[0051] The aromatic amine compound represented by the general formula (IV) has a small steric hindrance, and thus has an excellent curing property improvement effect, and can exhibit sufficient performance even with a short curing time. In addition, the aromatic amine compound represented by the general formula (IV) is liquid at room temperature, and thus is easily soluble in a solvent and easy to handle.

[0052] Specific examples of the aromatic amine compound represented by the general formula (IV) include diethyltoluenediamine represented by the following formula: [Chemistry 9] And 1,2-phenylenediamine, 1,3-phenylenediamine, 2,4-diaminotoluene, 2,6-diaminotoluene, 2,3-diaminotoluene, 3,4-diaminotoluene, 2,4,6-trimethyl-1,3-phenylenediamine, 1,2,4-triaminobenzene, 4,5-dimethyl-1,2-phenylenediamine, 1,4-phenylenediamine, 2,3,5,6-tetramethyl-1,4-phenylenediamine, etc.

[0053] The aromatic amine compound represented by the general formula (IV) may be used alone or in combination of two or more thereof. The preparation of these aromatic amine compounds is not particularly limited, and commercially available products may be used.

[0054] In the present embodiment, the blending ratio of the aromatic amine compound represented by the general formula (IV) in the epoxy resin composition can be 5 parts by mass or more and 50 parts by mass or less according to one example, and can be 10 parts by mass or more and 40 parts by mass or less according to another example, when the total amount of the epoxy resin and the aromatic amine compound is 100 parts by mass.

[0055] (Curing accelerator) The epoxy resin composition of the present embodiment preferably contains a curing accelerator. As the curing accelerator that can be used in the present embodiment, a boron-phosphorus complex represented by the following general formula (V) can be mentioned.

[0056] [Chemistry 10]

[0057] In the general formula (V), R2 and R3 each independently represent an alkyl group, r represents an integer from 0 to 5, and s represents an integer from 0 to 5. When r is an integer from 2 to 5, the multiple R2s present may be the same or different from each other. When s is an integer from 2 to 5, the multiple R3s present may be the same or different from each other.

[0058] R2 and R3 are any substituents on the benzene ring. Specific examples of the alkyl group represented by R2 and R3 include methyl and ethyl groups.

[0059] r, which represents the number of substitutions of R2 on the benzene ring substituted by the P atom, is 0 to 5, 0 to 3, 0 to 2, or 0 or 1. When r is 1, the configuration of the alkyl group represented by R2 may be any of the ortho, meta, or para positions relative to the P atom.

[0060] s, which represents the number of substitutions of R3 on the benzene ring substituted with the B atom, is 0 to 5, may be 0 to 3, may be 0 to 2, or may be 0.

[0061] Specific examples of the boron-phosphorus complex represented by the general formula (V) include triphenylphosphine triphenylborate (TPP-S) and tri-p-methylphenylphosphine triphenylborate (TPTP-S) shown in the following formula. However, in TPTP-S, the methyl group may be arranged at any of the ortho, meta, and para positions relative to the P atom.

[0062] [Chemistry 11]

[0063] In one embodiment, the epoxy resin composition of the present embodiment preferably contains TPP-S and / or TPTP-S as a curing accelerator.

[0064] The boron-phosphorus complex represented by the general formula (V) may be used alone or in combination of two or more thereof. The preparation of the boron-phosphorus complex represented by the general formula (V) is not particularly limited, and commercially available products may be used.

[0065] In the present embodiment, the blending ratio of the boron-phosphorus complex represented by the general formula (V) in the epoxy resin composition can be 0.01 to 5 parts by mass according to one example, and 0.1 to 5 parts by mass according to another example, when the total of the epoxy resin, the aromatic amine compound, and the epoxy-modified polybutadiene compound is 100 parts by mass.

[0066] As other curing accelerators that may be contained in the epoxy resin composition of this embodiment, a phosphorus compound represented by the following general formula (VI) may be mentioned. In this embodiment, the phosphorus compound represented by the following general formula (VI) is preferably used in combination with the boron-phosphorus complex represented by the above general formula (V).

[0067] [Chemistry 12]

[0068] In the general formula (VI), R4 represents an alkyl group or an alkoxy group, and t represents an integer of 0 to 5. When t is an integer of 2 or more, a plurality of R4s present may be the same as or different from each other.

[0069] R4 is an arbitrary substituent on the benzene ring. Specific examples of the alkyl group represented by R4 include methyl, ethyl, propyl, etc. Specific examples of the alkoxy group represented by R4 include methoxy, butoxy, etc.

[0070] t, which indicates the number of substitutions of R4 on the benzene ring, is 0 to 5, may be 0 to 4, may be 0 to 2, or may be 0.

[0071] Specific examples of the phosphorus compound represented by the general formula (VI) include triphenylphosphine (TPP) represented by the following formula.

[0072] [Chemistry 13]

[0072] The phosphorus compound represented by the general formula (VI) may be used alone or in combination of two or more thereof. The preparation of the phosphorus compound represented by the general formula (VI) is not particularly limited, and a commercially available product may be used.

[0073] The epoxy resin composition of the present embodiment contains an aromatic amine compound represented by the general formula (IV) as a curing agent, a boron-phosphorus complex represented by the general formula (V) as a curing accelerator, and a phosphorus compound represented by the general formula (VI). The voltage resistance, adhesion and heat resistance of the cured film obtained in a short curing time are all greatly improved. The reason may not be clear, but it is speculated as follows. That is, it is speculated that the curing reaction of the resin does not proceed at room temperature, and a rapid curing reaction will only occur when heated. Therefore, the molecular weight can be fully increased in a short time in the drying process, and it is easy to control, so it has a melt viscosity suitable for pressurization.

[0074] In the present embodiment, the compounding ratio of the phosphorus compound represented by the general formula (VI) in the epoxy resin composition can be 0.01 to 5 parts by mass according to one example, and 0.05 to 5 parts by mass according to another example, when the total of the epoxy resin, the aromatic amine compound, and the epoxy-modified polybutadiene compound is 100 parts by mass.

[0075] In addition, when determining the amount of the phosphorus compound represented by the general formula (VI), the amount of the boron-phosphorus complex represented by the general formula (V) is preferably considered. In one embodiment, [the total mass of the phosphorus compound represented by the general formula (VI) / the total mass of the boron-phosphorus complex represented by the general formula (V)] is preferably in the range of 0.002 to 5, and more preferably in the range of 0.1 or more and less than 1.

[0076] In addition, the total blending ratio of the boron-phosphorus complex represented by the general formula (V) and the phosphorus compound represented by the general formula (VI) in the epoxy resin composition can be 0.5 parts by mass or more and 10 parts by mass or less according to one example, and 1 part by mass or more and 10 parts by mass or less according to another example, when the total amount of the epoxy resin, the aromatic amine compound and the epoxy-modified polybutadiene compound is 100 parts by mass.

[0077] (Inorganic filler) The epoxy insulating composition of the present embodiment preferably contains an inorganic filler. Examples of the inorganic filler include aluminum oxide, aluminum nitride, boron nitride, silicon nitride, magnesium oxide, silicon oxide, etc. It is preferred to use one or more selected from these.

[0078] In the system that the epoxy resin composition of the present embodiment contains inorganic filler, there is a tendency to suppress the exothermic reaction produced by curing due to containing inorganic filler. Specifically, it is believed that there is a problem such as slowing down the curing reaction or hindering the curing reaction of thermosetting resin due to the surface functional groups of inorganic filler because the reaction heat is absorbed by the inorganic filler. Therefore, it is possible to use surface-treated inorganic filler, and it is also preferred to use inorganic filler with the appropriate combination of the above-mentioned curing accelerator. As the surface treatment of inorganic filler, for example, the surface of inorganic filler can be modified with the functional group that can be chemically bonded with the accompanying reaction of thermosetting resin, or it is also possible to modify (for example, cyanate group, epoxy group, amino, hydroxyl, carboxyl, vinyl, styryl, methacrylic group, acryl group, urea group, sulfhydryl, thioether group, isocyanate group etc.) with the high functional group of thermosetting resin compatibility, for example, silane coupling treatment or plasma treatment etc. can be used.

[0079] In the case where the epoxy resin composition of the present embodiment contains an inorganic filler, its blending ratio (the total blending ratio when containing two or more kinds) is preferably 30 volume % to 90 volume %, more preferably 50 volume % to 85 volume % based on the total volume of the epoxy resin, the epoxy-modified polybutadiene compound and the aromatic amine compound. If the filling rate is too low, not only the desired thermal conductivity cannot be obtained, but also the inorganic filler tends to precipitate. If the filling rate is too high, the viscosity is too high, and a uniform coating cannot be obtained, which may lead to an increase in pore defects.

[0080] In the epoxy resin composition of the present embodiment, by containing at least a specified amount of boron nitride (BN) as an inorganic filler, and making the proportion of boron nitride in the inorganic filler to be above a specified value, the heat-resistant adhesion can be further improved. Specifically, by making the proportion of the inorganic filler in the total volume of the epoxy resin, epoxy-modified polybutadiene compound and aromatic amine compound in the epoxy resin composition to be 50 volume % or more and 85 volume % or less, and making the proportion of boron nitride in the inorganic filler (hereinafter also referred to as "BN rate") preferably above 60 volume %, the heat-resistant adhesion can be further improved. The BN rate is more preferably above 65 volume %, and further preferably above 70 volume %.

[0081] This is surprising in view of the fact that boron nitride has almost no functional groups on the surface that contribute to the adhesion with resin, and therefore the adhesion strength tends to decrease as the proportion of boron nitride in the inorganic filler increases (see, for example, the claims of Patent Document 4, paragraphs 0078 and 0123, etc.). It is speculated that this phenomenon is the effect of the combined use of epoxy-modified polybutadiene compound and boron nitride, which will be described in detail later.

[0082] From the viewpoint of close fit and heat resistance, the upper limit of the BN rate in the inorganic filler is not particularly limited. The upper limit of the BN rate can be 100 volume % according to one example, 95 volume % according to another example, and 90 volume % according to another example. In addition, the BN rate of 100 volume % refers to the case where one boron nitride is contained as the inorganic filler.

[0083] (Solvent) The epoxy resin composition of the present embodiment preferably contains a solvent. The interlayer insulation resin sheet composed of the cured product of the epoxy resin composition of the present embodiment has a phase separation structure in which a non-continuous phase containing an epoxy-modified polybutadiene compound is dispersed in a continuous phase containing an epoxy resin. In order to form this phase separation structure, in the epoxy resin composition containing a solvent, it is preferred that the epoxy resin and the epoxy-modified polybutadiene compound are dissolved in the solvent to form a mutually uniformly dispersed state. When heated and cured from this state, the epoxy resin reacts with the amine curing agent, the molecular weight increases, and a continuous phase is formed, while the epoxy-modified polybutadiene compound having a lower reactivity than them partially condenses to form a non-continuous phase.

[0084] Therefore, as the solvent used in the epoxy resin composition, it is preferred that the solvent be capable of dissolving the epoxy resin and the epoxy-modified polybutadiene compound. As such a solvent, for example, amide solvents such as N,N-dimethylformamide (DMF), N,N-dimethylacetamide, N-methyl-2-pyrrolidone (NMP), ether solvents such as 1-methoxy-2-propanol, ethylene glycol monomethyl ether, ketone solvents such as methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), cyclohexanone, cyclopentanone, aromatic solvents such as toluene and xylene, etc. As the mode of use, one solvent may be used alone, or two or more solvents may be used in mixture.

[0085] (Other ingredients) The epoxy resin composition of the present embodiment may further contain other components. Examples of other components include coupling agents such as silane coupling agents and titanium coupling agents, ion adsorbents, anti-settling agents, anti-hydrolysis agents, leveling agents, antioxidants, and the like.

[0086] <Resin sheet for interlayer insulation> The resin sheet for interlayer insulation of the second embodiment is a sheet-like member composed of a cured product of the epoxy resin composition for interlayer insulation of the first embodiment, and can be obtained, for example, by heating and curing a coating film formed from an epoxy resin composition containing a solvent. The resin sheet for interlayer insulation of the present embodiment has a phase-separated structure in which a discontinuous phase containing an epoxy-modified polybutadiene compound is dispersed in a continuous phase containing an epoxy resin layer. The mechanism for forming such a phase-separated structure is as described above. That is, the epoxy resin and the epoxy-modified polybutadiene compound are dissolved in a solvent to form a mutually uniformly dispersed compatible state, and from this state, curing is carried out by heating. The molecular weight of a part of the epoxy-modified polybutadiene compound increases and the viscosity becomes high to form a discontinuous phase, and the epoxy resin with a lower viscosity forms a continuous phase (sea component), thereby forming a phase-separated structure (sea-island structure) in which a discontinuous phase (island component) containing an epoxy-modified polybutadiene compound is dispersed in a continuous phase (sea component) containing an epoxy resin.

[0087] The resin sheet for interlayer insulation of the present embodiment is formed from the epoxy resin composition of the first embodiment and contains the above-mentioned epoxy-modified polybutadiene compound having a 1,4-bond repeating unit, and thus has excellent heat resistance and adhesion and can maintain good withstand voltage even after, for example, solder reflow treatment. The mechanism will be described below based on the behavior of the loss tangent (tanδ) obtained by dynamic mechanical analysis (DMA).

[0088] In the resin sheet for interlayer insulation of the present embodiment, the glass transition temperature Tg can be determined by dynamic mechanical analysis (DMA). Specifically, using a dynamic mechanical analysis device, while changing the measurement temperature, the storage modulus (E') and the loss modulus (E") of the test piece of the resin sheet for interlayer insulation are determined. The temperature at which a peak top (maximum value) appears in the loss tangent (tanδ) represented by the ratio of the loss modulus (E") to the storage modulus (E') (E" / E') is the glass transition temperature Tg of the resin sheet for interlayer insulation.

[0089] In the loss tangent (tanδ) of the resin sheet for interlayer insulation having a phase-separated structure of a continuous phase containing an epoxy resin and a discontinuous phase of an epoxy-modified polybutadiene compound incompatible with the epoxy resin, there are a first peak of the first glass transition temperature Tg1 of the epoxy-modified polybutadiene compound and a second peak of the second glass transition temperature Tg2 of the epoxy resin. Here, the first glass transition temperature Tg1 and the second glass transition temperature Tg2 have a relationship of Tg1 < Tg2. Hereinafter, the first glass transition temperature Tg1 of the epoxy-modified polybutadiene compound will be referred to as "Tg1 of the epoxy-modified butadiene rubber phase", and the second glass transition temperature Tg2 of the epoxy resin will be referred to as "Tg2 of the epoxy resin phase", etc.

[0090] Figure 1 The present invention is a graph showing the behavior of the storage modulus (E'), loss modulus (E"), and loss tangent (tan δ) obtained by dynamic viscoelasticity measurement (DMA) of the interlayer insulation resin sheet manufactured using the epoxy resin composition of the first embodiment. Specifically, the present invention is a graph showing the behavior of the storage modulus (E'), loss modulus (E"), and loss tangent (tan δ) obtained by dynamic viscoelasticity measurement (DMA) of the insulation layer (interlayer insulation resin sheet) manufactured using the epoxy resin composition 1 prepared in Example 1 described later. The insulation layer contains bisphenol A type diglycidyl ether as an epoxy resin, and contains epoxy-modified butadiene rubber containing 1,4-bond repeating units and 1,2-bond repeating units as an epoxy-modified polybutadiene compound.

[0091] According to the intensive study by the present inventors, as an epoxy-modified butadiene rubber component incompatible with epoxy resin, when an epoxy-modified polybutadiene compound further containing 1,4-bond repeating units is used, Tg1 of the epoxy-modified butadiene rubber phase shifts to the low temperature side, while Tg2 of the epoxy resin phase shifts to the high temperature side, and the difference between Tg1 and Tg2 becomes larger, compared with the case of using the epoxy-modified polybutadiene compound composed of 1,2-bond repeating units used in Patent Document 3.

[0092] The lower the Tg1 of the epoxy-modified butadiene rubber phase, the lower the thermal expansion in the temperature range from Tg1 to Tg2 of the epoxy resin phase. Moreover, in a temperature region higher than Tg2, the thermal expansion suddenly increases, so the higher the Tg2 of the epoxy resin phase, the lower the expansion can be maintained. In this way, the larger the difference between Tg1 and Tg2, the more it can further suppress the thermal expansion of the insulating layer (resin sheet for interlayer insulation) until it reaches Tg2 of the epoxy resin phase during treatments such as the solder reflow process, so the interlayer insulation resin sheet of the present embodiment has improved heat resistance to close contact, and can maintain good voltage resistance to a high degree. Hereinafter, the larger difference between Tg1 and Tg2 is referred to as "low thermal expansion".

[0093] As described above, when boron nitride (BN) as an inorganic filler is used in combination with an epoxy-modified polybutadiene compound, the epoxy resin composition is mixed with boron nitride (BN) in a predetermined amount, and the proportion of boron nitride in the inorganic filler (BN ratio) becomes higher, the close contact heat resistance is further improved. In this case, the present inventors have confirmed that the difference between Tg1 and Tg2 is further increased, and the insulation layer has further reduced thermal expansion.

[0094] In the interlayer insulating resin sheet of the present embodiment, the first glass transition temperature Tg1 derived from the epoxy-modified polybutadiene compound is -5°C or lower in one example and -10°C or lower in another example, and the second glass transition temperature Tg2 derived from the epoxy resin is 175°C or higher in one example and 180°C or higher in another example.

[0095] The resin sheet for insulating layer of this embodiment has a phase separation structure including a continuous phase of epoxy resin and a discontinuous phase of epoxy-modified polybutadiene compound, and can be Figure 1 As shown in the loss tangent (tan δ), this was confirmed by the fact that the first peak derived from the first glass transition temperature Tg1 of the epoxy-modified polybutadiene compound and the second peak derived from the second glass transition temperature Tg2 of the epoxy resin did not overlap with each other.

[0096] In addition, the interlayer insulating resin sheet of the present embodiment has the above-mentioned phase separation structure, which can be confirmed by microscopic observation and / or scattering measurement in addition to the loss tangent (tanδ). In the case of microscopic observation, the phase separation structure can be confirmed by a scanning electron microscope (SEM), an atomic force microscope, an optical microscope, a transmission electron microscope, etc. In the case of scattering measurement, the phase separation structure can be confirmed by small-angle incident small-angle X-ray scattering measurement, elemental analysis, energy dispersive X-ray analysis, electron beam probe microanalyzer, X-ray photoelectron spectroscopy, etc. The details are described later. Figure 2 This is a photograph of a fracture surface of a cured product of the interlayer insulating epoxy resin composition of the present embodiment that does not contain an inorganic filler, and it can be seen that a phase separation structure is formed.

[0097] When the interlayer insulation resin sheet of the present embodiment contains an inorganic filler, the inorganic filler exists in both the discontinuous phase and the continuous phase. That is, the inorganic filler may exist in the discontinuous phase or the continuous phase.

[0098] <Laminate for circuit board> A circuit board laminate according to a third embodiment includes a metal substrate, an insulating layer provided on at least one surface of the metal substrate, and a metal foil provided on the insulating layer. Figure 4 1 is a perspective view schematically showing a laminate for a circuit substrate according to the present embodiment. Figure 5 yes Figure 4 The laminated body for a circuit board shown is a cross-sectional view taken along line II-II. Figure 4 and Figure 5The circuit board laminate 10 shown in the figure has a three-layer structure in which an insulating layer 12 is formed on one side of a metal substrate 11 and a metal foil 13 is formed on the insulating layer 12. In another embodiment, the circuit board laminate 10 may also be a five-layer structure in which insulating layers 12 are formed on both sides of the metal substrate 11 and metal foil 13 is formed on each insulating layer 12. In addition, Figure 4 and Figure 5 In the figure, the X and Y directions are directions parallel to the main surface of the metal substrate 2 and perpendicular to each other, and the Z direction is a thickness direction perpendicular to the X and Y directions. Figure 4 and Figure 5 In the figure, a rectangular circuit board laminate 10 is shown as an example, but the circuit board laminate 10 may have other shapes.

[0099] In the circuit substrate laminate 10, the metal substrate 11 is composed of, for example, a single metal or an alloy. As the material of the metal substrate 11, for example, aluminum, iron, copper, aluminum alloy or stainless steel can be used. The metal substrate 11 may also contain non-metals such as carbon. For example, the metal substrate 11 may contain aluminum composited with carbon. In addition, the metal substrate 11 may have a single-layer structure or a multi-layer structure.

[0100] The metal substrate 11 has a thermal conductivity. The metal substrate 11 typically has a thermal conductivity of 60 W·m -1 ·K -1 The metal substrate 11 may be flexible or inflexible. The thickness of the metal substrate 11 may be in the range of 0.2 mm to 5 mm, for example.

[0101] The metal foil 13 is provided on the insulating layer 12. The metal foil 13 faces the metal substrate 11 via the insulating layer 12. The metal foil 13 is made of, for example, a single metal or an alloy. As the material of the metal foil 13, for example, copper or aluminum can be used. The thickness of the metal foil 13 can be, for example, in the range of 10 μm to 500 μm.

[0102] The insulating layer 12 is a cured product of the epoxy resin composition of the first embodiment, that is, the interlayer insulating resin sheet of the second embodiment. Therefore, the insulating layer 12 has a phase separation structure including a continuous phase of the epoxy resin and a discontinuous phase of the epoxy-modified polybutadiene compound. The storage modulus (E') of the insulating layer 12 obtained by dynamic viscoelasticity measurement (DMA) shows Figure 1 The behavior shown in , the difference between the first glass transition temperature Tg1 from the epoxy-modified polybutadiene compound and the second glass transition temperature Tg2 from the epoxy resin is large, the heat-resistant adhesion is excellent, and the good withstand voltage can be maintained to a high degree. The thickness of the insulating layer 12 can be, for example, in the range of 50 μm to 300 μm.

[0103] The circuit board laminate 10 can be produced, for example, by the following method. First, the interlayer insulating epoxy resin composition of the present embodiment is applied to at least one of the metal substrate 11 and the metal foil 13 to form a coating film. The epoxy resin composition can be applied by, for example, a roller coating method, a rod coating method, or a screen printing method. It can be carried out in a continuous manner or in a single-plate manner. The coating film is dried as needed.

[0104] Next, the metal substrate 11 and the metal foil 13 are stacked so as to face each other with the coating film interposed therebetween, and then they are heat-pressed. In the above manner, the circuit board laminate 10 is obtained.

[0105] In this method, a coating film is formed by applying the epoxy resin composition of this embodiment to at least one of the metal substrate 11 and the metal foil 13, but in other embodiments, the epoxy resin composition can also be applied to a substrate such as a PET film and dried to form a coating film in advance, and then thermally transferred to one of the metal substrate 11 and the metal foil 13.

[0106] <Metal base circuit board> Next, a metal base circuit board according to a fourth embodiment will be described. Figure 6 1 is a cross-sectional view schematically showing a metal base circuit board according to a fourth embodiment. Figure 6 The metal base circuit board 20 shown in the figure comprises a metal base board 11, an insulating layer 12 and a circuit pattern 13a in this order. Figure 4 and Figure 5 The circuit board laminate 10 of the third embodiment shown is obtained by patterning the metal foil 13 of the circuit board laminate 10 to obtain the circuit pattern 13a. The patterning is obtained, for example, by forming a mask pattern on the metal foil 13 and etching away the exposed portion of the metal foil 13. The metal base circuit board 20 can be obtained, for example, by patterning the metal foil 13 of the previous circuit board laminate 10 and performing processing such as cutting and punching as needed.

[0107] The metal base circuit board 20 of this embodiment is obtained from the above-mentioned circuit board laminate 10. Since it has an insulating layer 12 composed of the interlayer insulating resin sheet of the second embodiment, the metal base circuit board 20 has excellent heat-resistant adhesion and can maintain good voltage resistance even after, for example, solder reflow treatment.

[0108] <Power Module> Figure 71 is a cross-sectional view schematically showing a power module 100 of the fifth embodiment. The power module 100 includes a metal substrate 11, an insulating layer 12, and a metal base circuit substrate 20 of the fourth embodiment including a circuit pattern 13a. Therefore, the power module 100 of this embodiment has excellent heat-resistant adhesion and can maintain good voltage resistance even after, for example, solder reflow treatment. In the current situation where the heat generation temperature tends to increase with the high performance of power devices, the module of the embodiment of the present invention can also be applied to temperature regions that the existing power modules cannot cope with.

[0109] in addition, Figure 7 In the power module 100 shown, 101 represents a power device, 102 represents a solder layer, 103 represents a heat sink, and 104 represents a heat sink.

[0110] Furthermore, the power module 100 of this embodiment is Figure 8 Compared with the conventional power module 110 shown as an example in FIG. 1 , the metal base circuit substrate 20 of this embodiment has fewer components (layers) and a thinner overall thickness, so a compact design with lower thermal resistance can be achieved. In addition, since processing such as drilling and cutting is easy, it also has the advantage of easy assembly.

[0111] in addition, Figure 8 In the conventional power module 110 shown, 101 represents a power device, 102a represents a first solder layer, 13a represents a circuit pattern, 105 represents a ceramic substrate, 106 represents a metallization layer, 102b represents a second solder layer, 11 represents a metal substrate, 103 represents a heat sink, and 104 represents a heat sink. Example

[0112] <Preparation of epoxy resin composition> Epoxy resin compositions 1 to 4 and 101 to 104 were prepared by the method shown below. (Example 1) Bisphenol A diglycidyl ether, epoxy-modified polybutadiene compound 1, diethyltoluenediamine as a curing agent, triphenylphosphine triphenylborane as a curing accelerator 1, and triphenylphosphine as a curing accelerator 2 were mixed in the blending ratios shown in Table 1 described below to obtain a mixture 1. The numbers for the blending ratios in Table 1 represent parts by mass excluding the inorganic filler.

[0113] Next, to the obtained mixture 1, an alumina filler (Al2O3) and a boron nitride filler (BN) in a ratio of 20:45 (volume ratio) as inorganic fillers are added in an amount of 65 volume % relative to the total volume of bisphenol A diglycidyl ether, aromatic amine compound and epoxy-modified polybutadiene compound 1, thereby obtaining a mixture 2.

[0114] Then, methyl ethyl ketone (MEK) as a solvent was added to the obtained mixture 2 until the nonvolatile content concentration became 79 mass %, thereby preparing an epoxy resin composition 1 (slurry) having a viscosity suitable for coating.

[0115] The details of each raw material used in the preparation of the above-mentioned mixture 1 are as follows. Bisphenol A diglycidyl ether: trade name EXE850 CRP, manufactured by DIC Corporation, Mw 300-1500. Epoxy-modified polybutadiene compound 1: trade name Ricon (registered trademark) 657E, manufactured by Cray Valley Corporation, Mn about 1900, repeating unit: [Chemistry 14]

[0116] Curing agent: diethyltoluenediamine represented by the following formula (trade name DETDA-80; manufactured by Lonza Corporation) [Chemistry 15]

[0117] Curing accelerator 1: triphenylphosphine triphenylborane (trade name TPP-S; produced by Hokko Chemical Industry Co., Ltd.) [Chemistry 16]

[0118] Curing accelerator 2: triphenylphosphine (trade name TPP; manufactured by Hokko Chemical Industry Co., Ltd.) [Chemistry 17]

[0119] (Example 2) With respect to Example 1, except that the blending ratio of the epoxy-modified polybutadiene compound 1 was changed to the blending ratio shown in Table 1, an epoxy resin composition 2 was prepared in the same manner as in Example 1.

[0120] (Example 3) Epoxy resin composition 3 was prepared in the same manner as in Example 1 except that the volume ratio (20:45) of the alumina filler (Al 2 O 3 ) and the boron nitride filler (BN) was changed to the volume ratio shown in Table 1.

[0121] (Example 4) Epoxy resin composition 4 was prepared in the same manner as in Example 2 except that the volume ratio (20:45) of the alumina filler (Al 2 O 3 ) and the boron nitride filler (BN) was changed to the volume ratio shown in Table 1.

[0122] (Comparative Example 1) An epoxy resin composition 101 was prepared in the same manner as in Example 1 except that the epoxy-modified polybutadiene compound 1 was changed to the epoxy-modified polybutadiene compound 2 represented by the following formula. Epoxy-modified polybutadiene compound 2: trade name JP200, produced by Nippon Soda Co., Ltd., Mw 2200, repeating unit: [Chemistry 18]

[0123] (Comparative Example 2) With respect to Comparative Example 1, except that the blending ratio of the epoxy-modified polybutadiene compound 2 was changed to the blending ratio shown in Table 1, an epoxy resin composition 102 was prepared in the same manner as in Comparative Example 1.

[0124] (Comparative Example 3) An epoxy resin composition 103 was prepared in the same manner as in Comparative Example 1 except that the volume ratio (20:45) of the alumina filler (Al 2 O 3 ) and the boron nitride filler (BN) was changed to the volume ratio shown in Table 1.

[0125] (Comparative Example 4) An epoxy resin composition 104 was prepared in the same manner as in Comparative Example 2 except that the volume ratio (20:45) of the alumina filler (Al 2 O 3 ) and the boron nitride filler (BN) was changed to the mass ratio shown in Table 1.

[0126] <Confirmation of phase separation structure> For Example 1 and Comparative Example 1, epoxy resin compositions 1a and 101a were prepared by the same methods as in Example 1 and Comparative Example 1, except that no inorganic filler was added. The fracture surfaces of the test pieces composed of the cured products of these epoxy resin compositions were observed under a microscope. The fracture surface photograph of the epoxy resin composition 1a is Figure 2 The fracture surface photo of epoxy resin composition 101a is Figure 3 It was confirmed that a phase separation structure was formed in either case.

[0127] <Manufacturing of test specimen> Each epoxy resin composition prepared above was coated on a PET film using a coater and heated at 80°C for 40 minutes to dry the solvent to obtain a dry coating film. Each obtained coating film was thermally transferred onto a 2.0 mm thick copper substrate. Circuit copper with a thickness of 0.5 mm was temporarily bonded by overlapping the copper plate with the coating film interposed therebetween, and heat-treated at 185° C. for 1 hour to obtain test pieces of metal-based circuit boards having an insulating layer with a thickness of 120 μm.

[0128] <Dynamic Viscoelasticity Measurement (DMA)> From each test body manufactured as described above, the base copper and circuit copper are removed by etching, and the insulating layer is taken out to obtain a test piece with a width of 2 mm, a length of 60 mm, and a film thickness of 120 μm. Using the test piece, dynamic viscoelasticity measurement (determination of storage modulus (E'), loss modulus (E") and loss tangent (tanδ)) is carried out under the following conditions. The glass transition temperatures Tg1 and Tg2 obtained from the loss tangent (tanδ) in each test piece are shown in Table 1. Tg1 is the glass transition temperature of the epoxy-modified butadiene rubber phase, and Tg3 is the glass transition temperature of the epoxy resin phase. In addition, the dynamic viscoelasticity measurement data obtained from each test piece is shown in the figure showing the dynamic viscoelasticity measurement data of Example 1 Figure 1 .

[0129] · Apparatus: Dynamic viscoelasticity measuring apparatus (manufactured by TA Instruments) Measurement mode: stretching mode Heating rate: 2℃ / min Frequency: 1Hz ·Atmosphere: N2 Temperature range: -50℃~300℃

[0130] <Adhesion and heat resistance> After each test body was floated in a solder bath at a temperature of 300°C for 5 minutes, an ultrasonic flaw detector (Scanning acoustic tomograph; SAT) was used to confirm whether the metal base substrate and the bonding interface with the circuit substrate were peeled off. Repeat until peeling occurs, measure the number of tolerances (holding times) without peeling, and evaluate according to the following criteria. The more times it is held, the better the heat resistance of the adhesion. The results are shown in Table 1. (Number of holds) 3 or more times: A 2nd: B 0 or 1 time: C

[0131] <Withstand voltage after welding> In the above-mentioned close contact heat resistance test, the withstand voltage is measured for each test body after the operation of floating in the solder bath for 5 minutes until the material temperature reaches 300°C is repeated twice. In addition, for the test body that has peeled off under the circuit, the withstand voltage can also be measured as long as the adhesion with the insulating layer is maintained. The withstand voltage is increased by 0.2KV every 5 seconds, and the voltage when the insulation is broken is the withstand voltage. The results are shown in Table 1.

[0132] Table 1

[0133] The results shown in Table 1 show that by using a compound containing a repeating unit derived from 1,4-bonded butadiene instead of a compound containing a repeating unit derived from 1,2-bonded butadiene as the epoxy-modified polybutadiene compound, the adhesion heat resistance is improved and the withstand voltage can be maintained at a high level.

[0134] In addition, the present invention is not limited to the above-mentioned embodiments, and various modifications can be made in the implementation stage without departing from the scope of the main purpose. In addition, each embodiment can also be implemented in appropriate combination, in which case the effect of the combination can be obtained. In addition, the above-mentioned embodiments include various inventions, and various inventions can be extracted by combining selected from the disclosed multiple constituent elements. For example, even if several constituent elements are deleted from all the constituent elements shown in the embodiment, in the case where the technical problem can be solved and the effect can be obtained, the structure after deleting the constituent element can be extracted as an invention.

[0135] Explanation of symbols 10Laminate for circuit board 11 metal substrate 12 Insulation layer 13 metal foil 13a Circuit pattern 20Metal base circuit board 100 Power Modules 110 Existing power modules 101 Power Devices 102 solder layer 102a First solder layer 102b Second solder layer 103 heat sink 104 Radiator 105 Ceramic Substrate 106 metallization layer

Claims

1. An epoxy resin composition for interlayer insulation, comprising: an epoxy resin, an epoxy-modified polybutadiene compound and an aromatic amine compound, wherein the epoxy-modified polybutadiene compound comprises a repeating unit represented by the following general formula (I), a repeating unit represented by the following general formula (II) and a repeating unit represented by the following general formula (III), and comprises at least one of a repeating unit represented by the following general formula (i), a repeating unit represented by the following general formula (ii) and a repeating unit represented by the following general formula (iii), [Chemistry 1] 2. The epoxy resin composition for interlayer insulation according to claim 1, wherein At least bisphenol A diglycidyl ether is contained as the epoxy resin.

3. The epoxy resin composition for interlayer insulation according to claim 1 or 2, wherein: The aromatic amine compound includes a compound represented by the following general formula (IV): [Chemistry 2] In the general formula (IV), R1 represents an alkyl group, m represents an integer greater than 2, and n represents an integer greater than 0, and m and n satisfy m+n≤6. When n is greater than 2, multiple R1s present may be the same as or different from each other.

4. The epoxy resin composition for interlayer insulation according to any one of claims 1 to 3, wherein Containing a boron-phosphorus complex represented by the following general formula (V) and a phosphorus compound represented by the following general formula (VI), [Chemistry 3] In the general formula (V), R2 and R3 each independently represent an alkyl group, r represents an integer from 0 to 5, s represents an integer from 0 to 5, when r is an integer from 2 to 4, the multiple R2s present may be the same or different from each other, when s is an integer from 2 to 4, the multiple R3s present may be the same or different from each other, [Chemistry 4] In the general formula (VI), R4 represents an alkyl group or an alkoxy group, t represents an integer of 0 to 5, and when t is an integer of 2 to 5, a plurality of R4s present may be the same as or different from each other.

5. The epoxy resin composition for interlayer insulation according to any one of claims 1 to 4, wherein Contains inorganic filler materials.

6. The epoxy resin composition for interlayer insulation according to claim 5, wherein The inorganic filler contains at least boron nitride, the inorganic filler accounts for 50 volume % to 85 volume % of the total volume of the epoxy resin, the epoxy-modified polybutadiene compound and the aromatic amine compound, and the boron nitride accounts for 60 volume % or more of the inorganic filler. 7 . An interlayer insulating resin sheet comprising a cured product of the interlayer insulating epoxy resin composition according to claim 1 , having a phase separation structure in which a discontinuous phase containing the epoxy-modified polybutadiene compound is dispersed in a continuous phase containing the epoxy resin.

8. The interlayer insulating resin sheet according to claim 7, wherein The first glass transition temperature Tg1 derived from the epoxy-modified polybutadiene compound is below -5°C, and the second glass transition temperature Tg2 derived from the epoxy resin is above 175°C.

9. A laminate for a circuit substrate, comprising a metal substrate, an insulating layer provided on at least one surface of the metal substrate, and a metal foil provided on the insulating layer, wherein: The insulating layer is the interlayer insulating resin sheet according to claim 7 or 8.

10. A metal base circuit board, which is a laminate for a circuit board comprising a metal substrate, an insulating layer provided on at least one surface of the metal substrate, and a circuit pattern provided on the insulating layer, wherein: The insulating layer is the interlayer insulating resin sheet according to claim 7 or 8. 11 . A power module comprising the metal base circuit board according to claim 10 .

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