Sealing resin composition and power semiconductor device

Abstract

A sealing resin composition containing an epoxy resin, a maleimide compound having a biphenyl structure, and a curing agent.

Description

Encapsulation resin composition and power semiconductor device

[0001] The present invention relates to a encapsulating resin composition and a power semiconductor device.

[0002] Power semiconductor devices are a type of semiconductor device primarily used for controlling the voltage or frequency of power, and for converting DC to AC or AC to DC. They are used in various fields that utilize power as a power source, such as electronic equipment, motors, and power generation devices. In recent years, there has been a shift from conventional Si devices to SiC devices in power semiconductor devices, and it is expected that operating temperatures and rated voltages will be increased. Therefore, conventional epoxy resin compositions that have been used until now lack sufficient heat resistance, and encapsulation materials that can withstand use at higher operating temperatures are required. Power semiconductor devices generate a large amount of heat during use, which tends to lead to a decrease in reliability during operation. Therefore, power semiconductor modules containing power semiconductor devices are required to have electrical reliability that can withstand use under high voltage and high current conditions. Resin compositions containing epoxy resin are widely used as resin compositions for encapsulating power semiconductor devices (see, for example, Patent Document 1).

[0003] International Publication No. 2013 / 047696

[0004] In power semiconductor devices, nickel-plated lead frames, for example, are used as conductive materials. To suppress a decrease in reliability, it is necessary to achieve a higher level of adhesion between the resin composition used to encapsulate the power semiconductor element and nickel.

[0005] This disclosure aims to provide a sealing resin composition capable of forming a sealing portion that suppresses peeling from nickel, and a power semiconductor device manufactured using this sealing resin composition.

[0006] This disclosure includes the following forms: <1> A encapsulation resin composition comprising an epoxy resin, a maleimide compound having a biphenyl structure, and a curing agent. <2> The encapsulation resin composition according to <1>, wherein the total content of the maleimide compound having a biphenyl structure is 30% by mass or more relative to the content of the epoxy resin. <3> The encapsulation resin composition according to <1> or <2>, comprising a sulfur-containing compound. <4> The encapsulation resin composition according to any one of <1> to <3>, wherein the curing agent comprises a phenol resin. <5> The encapsulation resin composition according to any one of <1> to <4>, for encapsulating power semiconductor elements. <6> A power semiconductor device comprising a power semiconductor element, an insulating substrate, and a heat dissipation member in this order, wherein the power semiconductor element is encapsulated with a cured product of the encapsulation resin composition according to any one of <1> to <5>.

[0007] This disclosure provides a sealing resin composition capable of forming a sealing portion in which peeling from nickel is suppressed, and a power semiconductor device manufactured using this sealing resin composition.

[0008] This is a schematic cross-sectional view showing an example of a power semiconductor device.

[0009] Embodiments of the present disclosure will be described in detail below. However, the present disclosure is not limited to the following embodiments. In the following embodiments, the components (including elemental steps, etc.) are not essential unless otherwise specified. The same applies to numerical values ​​and their ranges, and they do not limit the present disclosure. In numerical ranges indicated using "~" in the present disclosure, the numerical values ​​before and after "~" are included as the minimum and maximum values, respectively. In numerical ranges described in stages in the present disclosure, the upper or lower limit of one numerical range may be replaced with the upper or lower limit of another numerical range described in stages. Also, in numerical ranges described in the present disclosure, the upper or lower limit of that numerical range may be replaced with the value shown in the example. In the present disclosure, each component may contain multiple types of the corresponding substance. If multiple types of the substance corresponding to each component are present in the composition, the content or amount of each component means the total content or amount of the multiple types of substances present in the composition unless otherwise specified. In the present disclosure, each component may contain multiple types of particles. If multiple types of particles corresponding to each component are present in the composition, the particle size of each component refers to the value for a mixture of such multiple types of particles present in the composition, unless otherwise specified. In this disclosure, the term "layer" includes cases where the layer is formed not only over the entire region when the region in which the layer exists is observed, but also where it is formed only on a part of the region.

[0010] <Resin Composition> The encapsulating resin composition of this disclosure contains an epoxy resin, a maleimide compound having a biphenyl structure, and a curing agent. Hereinafter, the "encapsulating resin composition" will also be simply referred to as the "resin composition." The "maleimide compound having a biphenyl structure" will also be referred to as the "specific maleimide compound." The reason why the above problems are solved in the resin composition having the above configuration is thought to be as follows.

[0011] As power semiconductor devices become larger, the impact of substrate warping is becoming more significant. Substrate warping occurs due to the difference in thermal expansion coefficients between the substrate and the encapsulation area. When power semiconductor devices are small, even if the substrate warps due to heating, the absolute value of the warping is small. However, as the substrate size increases, the impact of warping becomes apparent.

[0012] Therefore, this disclosure solves the above problem by changing the resin system. Specifically, the resin composition contains a maleimide compound in addition to an epoxy resin. In this resin system, it is expected that the curing reaction will involve reactions between epoxy resins and between maleimide compounds, as well as a reaction between the epoxy resin and the maleimide compound, resulting in a complex reactant. This will result in a cured product with a high glass transition temperature. In particular, because the maleimide compound has a biphenyl structure, a benzene ring is incorporated into the reactant, resulting in a cured product with an even higher glass transition temperature.

[0013] Generally, the adhesive strength of a sealing portion decreases significantly at high temperatures. However, a sealing portion made from a cured product of the resin composition of this disclosure, which has a high glass transition temperature, does not lose adhesive strength even at high temperatures. Therefore, the sealing portion obtained from the resin composition of this disclosure exhibits reduced peeling from nickel.

[0014] The resin composition of this disclosure may optionally contain curing accelerators, inorganic fillers, coupling agents, ion exchangers, mold release agents, stress relaxants, flame retardants, colorants, etc. From the viewpoint of further suppressing peeling of the cured encapsulated portion from the substrate, the resin composition of this disclosure preferably contains a sulfur-containing compound. The sulfur-containing compound may be contained as an epoxy resin, as a curing agent, or as a coupling agent. The sulfur-containing compound may be used alone or in combination of two or more. The main components constituting the resin composition of this disclosure are described below.

[0015] (Epoxy resin) The type of epoxy resin included in the resin composition is not particularly limited and can be selected from those commonly used in resin compositions for sealing. Specifically, these include: novolac-type epoxy resins (phenol novolac-type epoxy resins, orthocresol novolac-type epoxy resins, etc.) obtained by condensing or co-condensing a novolac resin obtained by condensing or co-condensing a phenolic compound selected from the group consisting of phenol compounds such as phenol, cresol, xylenol, resorcinol, catechol, bisphenol A, bisphenol F, and naphthol compounds such as α-naphthol, β-naphthol, and dihydroxynaphthalene, with an aliphatic aldehyde compound such as formaldehyde, acetaldehyde, or propionaldehyde under an acidic catalyst; triphenylmethane-type epoxy resins obtained by condensing or co-condensing a triphenylmethane-type phenolic resin obtained by condensing or co-condensing the above phenolic compound with an aromatic aldehyde compound such as benzaldehyde or salicylaldehyde under an acidic catalyst; and copolymer-type epoxy resins obtained by epoxidizing a novolac resin obtained by co-condensing the above phenolic compound and naphthol compound with an aldehyde compound under an acidic catalyst. Epoxy resins; diphenylmethane type epoxy resins which are diglycidyl ethers of bisphenol A, bisphenol F, etc.; biphenyl type epoxy resins which are diglycidyl ethers of alkyl-substituted or unsubstituted biphenols; stilbene type epoxy resins which are diglycidyl ethers of stilbene-based phenol compounds; sulfur atom-containing epoxy resins such as diglycidyl ethers of bisphenol S, thioether type epoxy resins, and bisphenol sulfide type epoxy resins; epoxy resins which are glycidyl ethers of alcohols such as butanediol, polyethylene glycol, and polypropylene glycol; glycidyl ester type epoxy resins which are glycidyl esters of polycarboxylic acid compounds such as phthalic acid, isophthalic acid, and tetrahydrophthalic acid; glycidylamine type epoxy resins in which the active hydrogen bonded to the nitrogen atom of aniline, diaminodiphenylmethane, isocyanuric acid, etc. is substituted with a glycidyl group; dicyclopentadiene type epoxy resins which are epoxidized from a co-condensation resin of dicyclopentadiene and a phenol compound;Alicyclic epoxy resins such as vinylcyclohexene diepoxide, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, and 2-(3,4-epoxy)cyclohexyl-5,5-spiro(3,4-epoxy)cyclohexane-m-dioxane, which have epoxidized olefin bonds within the molecule; paraxylylene-modified epoxy resins, which are glycidyl ethers of paraxylylene-modified phenol resins; metaxylylene-modified epoxy resins, which are glycidyl ethers of metaxylylene-modified phenol resins; terpene-modified epoxy resins, which are glycidyl ethers of terpene-modified phenol resins; and dicyclopentadiene-modified phenol resins, which are glycidyl ethers of dicyclopentadiene-modified phenol resins. Examples of epoxy resins include: cyclopentadiene-modified epoxy resins, which are glycidyl ethers of cyclopentadiene-modified phenolic resins; polycyclic aromatic ring-modified epoxy resins, which are glycidyl ethers of polycyclic aromatic ring-modified phenolic resins; naphthalene-type epoxy resins, which are glycidyl ethers of naphthalene ring-containing phenolic resins; halogenated phenol novolac-type epoxy resins; hydroquinone-type epoxy resins; trimethylolpropane-type epoxy resins; linear aliphatic epoxy resins obtained by oxidizing olefin bonds with peracids such as peracetic acid; and aralkyl-type epoxy resins, which are epoxidized aralkyl-type phenolic resins such as biphenyl aralkyl resins, phenol aralkyl resins, and naphthol aralkyl resins. Furthermore, epoxides of silicone resins and acrylic resins can also be cited as epoxy resins. These epoxy resins may be used individually or in combination of two or more types.

[0016] From the viewpoint of further increasing the glass transition temperature of the sealed portion formed by curing, it is preferable to include a triphenylmethane type epoxy resin. The proportion of the triphenylmethane type epoxy resin to the total amount of epoxy resin is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more. Furthermore, from the viewpoint of balancing various properties such as elastic modulus, fluidity, heat resistance, and moldability, the proportion of the triphenylmethane type epoxy resin to the total amount of epoxy resin may be 100% by mass, preferably 98% by mass or less, more preferably 95% by mass or less, and even more preferably 93% by mass or less.

[0017] From the viewpoint of further increasing the glass transition temperature of the sealed portion formed by curing, it is preferable to include a naphthalene-type epoxy resin. The proportion of triphenylmethane-type epoxy resin to the total amount of epoxy resin is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more. Furthermore, from the viewpoint of balancing various properties such as elastic modulus, fluidity, heat resistance, and moldability, the proportion of triphenylmethane-type epoxy resin to the total amount of epoxy resin may be 100% by mass, preferably 98% by mass or less, more preferably 95% by mass or less, and even more preferably 93% by mass or less.

[0018] From the viewpoint of reducing water absorption and improving adhesion to nickel, it is preferable to include a biphenyl aralkyl type epoxy resin. The proportion of the biphenyl aralkyl type epoxy resin to the total amount of epoxy resin is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more. Furthermore, from the viewpoint of balancing various properties such as elastic modulus, fluidity, heat resistance, and moldability, the proportion of the triphenylmethane type epoxy resin to the total amount of epoxy resin may be 100% by mass, preferably 98% by mass or less, more preferably 95% by mass or less, and even more preferably 93% by mass or less.

[0019] From the viewpoint of further suppressing peeling of the cured and formed sealing portion from the substrate, it is preferable to include a sulfur atom-containing epoxy resin. Examples of sulfur atom-containing epoxy resins include thioether-type epoxy resins.

[0020] The proportion of sulfur atom-containing epoxy resin to the total amount of epoxy resin is preferably 5% by mass or more, more preferably 8% by mass or more, and even more preferably 10% by mass or more. Furthermore, from the viewpoint of balancing various properties such as elastic modulus, fluidity, heat resistance, and moldability, the proportion of sulfur atom-containing epoxy resin to the total amount of epoxy resin is preferably 40% by mass or less, more preferably 30% by mass or less, and even more preferably 25% by mass or less.

[0021] The epoxy equivalent (molecular weight / number of epoxy groups) of the epoxy resin is not particularly limited. From the viewpoint of balancing various properties such as elastic modulus, fluidity, heat resistance, and moldability, it is preferably 100 g / eq to 1000 g / eq, and more preferably 150 g / eq to 500 g / eq. The epoxy equivalent of the epoxy resin shall be the value measured by the method in accordance with JIS K 7236:2009.

[0022] When the epoxy resin is solid, its softening point or melting point is not particularly limited. From the viewpoint of moldability and reflow resistance, it is preferably 40°C to 180°C, and from the viewpoint of ease of handling during the preparation of the resin composition, it is more preferably 50°C to 130°C. The melting point of the epoxy resin shall be the value measured by differential scanning calorimetry (DSC), and the softening point of the epoxy resin shall be the value measured by the method (ring-ball method) in accordance with JIS K 7234:1986.

[0023] The epoxy resin content in the resin composition is preferably 0.5% to 50% by mass, and more preferably 2% to 30% by mass, from the viewpoint of elastic modulus, fluidity, heat resistance, moldability, etc.

[0024] (Specific Maleimide Compounds) Specific maleimide compounds have a biphenyl structure. The number of maleimide groups in a specific maleimide compound may be one or more, or two or more. Maleimide compounds may contain amine compounds as synthesis raw materials. Specific maleimide compounds may be used individually or in combination of two or more.

[0025] A specific maleimide compound may have structures other than the maleimide group and the biphenyl structure. An example of such a structure is the aralkyl structure. The alkylene group in the aralkyl structure may be linear or branched. The number of carbon atoms in the alkylene group in the aralkyl structure is more preferably 1 or 2, and even more preferably 1. Examples of aryl groups in the aralkyl structure include the phenyl group, the naphthyl group, and the anthracenyl group, and it is preferable to include at least one selected from the group consisting of the phenyl group and the naphthyl group, and it is preferable to include the phenyl group.

[0026] When a specific maleimide compound has an aralkyl structure, it is preferable that the maleimide group is bonded to the aryl group in the aralkyl group. The aryl group in the aralkyl structure may or may not have substituents.

[0027] When a specific maleimide compound has both a biphenyl structure and an aralkyl structure, it may have multiple biphenylaralkyl units, in which an aralkyl unit is linked to biphenylene. An example of a specific maleimide compound having multiple biphenylaralkyl units is a resin represented by the following formula (I).

[0028]

[0029] In formula (I), R １ and R ２ Each of the following independently represents a substituent: n independently represents an integer from 0 to 4, and m represents an integer of 1 or greater. １ and R ２Examples of substituents represented by include alkyl groups and phenyl groups. Each n is preferably an integer between 0 and 2, more preferably 0 or 1, and even more preferably 0. m is preferably between 1 and 5, and more preferably greater than 1 and less than or equal to 5.

[0030] R １ and R ２ The alkyl group represented by R may be either linear or branched. １ and R ２ The alkyl group represented is preferably an alkyl group having 1 to 5 carbon atoms, and more preferably an alkyl group having 1 to 3 carbon atoms. Specifically, examples include methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, sec-butyl group, isobutyl group, tert-butyl group, pentyl group, and neopentyl group.

[0031] The number-average molecular weight of the specific maleimide compound is preferably 150 to 2000, and more preferably 400 to 1300. Furthermore, the weight-average molecular weight of the specific maleimide compound is preferably 150 to 2500, and more preferably 400 to 1500.

[0032] Furthermore, the maleimide compound represented by formula (I) preferably contains a difunctional group represented by m = 1 in formula (I) in an amount of 30% to 70% by mass, and more preferably 50% to 70% by mass. Furthermore, the maleimide compound represented by formula (I) preferably contains a polyfunctional group of three or more functions represented by m = 2 or more in formula (I) in an amount of 30% to 70% by mass, and more preferably 30% to 50% by mass. Furthermore, the maleimide compound represented by formula (I) may contain a monofunctional group represented by m = 0 in formula (I), or it may contain polyfunctional groups such as heptafunctional groups or octafunctional groups represented by m = 6 or more in formula (I), as long as the average value of the degree of polymerization, m, is between 1 and 5.

[0033] An example of a resin represented by formula (I) is the resin represented by formula (II) below.

[0034]

[0035] m in formula (II) has the same meaning as m in formula (I).

[0036] The encapsulating resin composition of the present disclosure may contain other maleimide compounds in addition to the specific maleimide compound. In the total amount of the maleimide compound, the content of the specific maleimide compound is preferably 10% by mass or more, preferably 20% by mass or more, preferably 30% by mass or more, and may be 40% by mass or more, 50% by mass or more, 60% by mass or more, 70% by mass or more, 80% by mass or more, 90% by mass or more, or 100% by mass.

[0037] Examples of other maleimide compounds include monofunctional maleimide compounds having one maleimide group in the molecule and polyfunctional maleimide compounds having two or more maleimide groups in the molecule (excluding the specific maleimide compound). Examples of the monofunctional maleimide compound include chlorophenyl maleimide such as o-chlorophenyl maleimide, methylphenyl maleimide such as o-methylphenyl maleimide, hydroxyphenyl maleimide such as p-hydroxyphenyl maleimide, carboxyphenyl maleimide such as p-carboxyphenyl maleimide, N-dodecyl maleimide, phenylmethane maleimide, and the like. Examples of the polyfunctional maleimide compound include 4,4'-diphenylmethane bismaleimide, polyphenylmethane maleimide, phenylene bismaleimide such as m-phenylene bismaleimide, bisphenol A diphenyl ether bismaleimide, 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethane bismaleimide, 4-methyl-1,3-phenylene bismaleimide, 1,6'-bismaleimide-(2,2,4-trimethyl)hexane, 4,4'-diphenyl ether bismaleimide, 4,4'-diphenyl sulfone bismaleimide, 1,3-bis(3-maleimidophenoxy)benzene, 1,3-bis(4-maleimidophenoxy)benzene, and the like.

[0038] From the viewpoint of further suppressing the peeling of the cured sealing portion from the substrate, the total content of the maleimide compound is preferably 30% by mass or more, more preferably 40% by mass or more, and still more preferably 45% by mass or more, based on the content of the epoxy resin. Further, the total content of the maleimide compound is preferably 200% by mass or less, more preferably 180% by mass or less, and still more preferably 150% by mass or less, based on the content of the epoxy resin.

[0039] (Curing agent) The resin composition contains a curing agent. The type of the curing agent is not particularly limited, and examples thereof include a phenol curing agent, an amine curing agent, an acid anhydride curing agent, a polymercaptan curing agent, a polyaminoamide curing agent, an isocyanate curing agent, a blocked isocyanate curing agent, and the like. From the viewpoint of further suppressing the peeling of the cured sealing portion from the substrate, the curing agent preferably contains one having two or more phenolic hydroxyl groups in one molecule (phenol curing agent). The curing reaction of the maleimide compound is likely to be promoted by the phenolic hydroxyl group of the phenol curing agent.

[0040] Specifically, the phenolic curing agents include polyhydric phenolic compounds such as resorcinol, catechol, bisphenol A, bisphenol F, and substituted or unsubstituted biphenols; novolac-type phenolic resins obtained by condensing or co-condensing at least one phenolic compound selected from the group consisting of phenolic compounds such as phenol, cresol, xylenol, resorcinol, catechol, bisphenol A, bisphenol F, phenylphenol, aminophenol, and naphthol compounds such as α-naphthol, β-naphthol, and dihydroxynaphthalene, with aldehyde compounds such as formaldehyde, acetaldehyde, propionaldehyde, benzaldehyde, and salicylaldehyde under an acidic catalyst; and synthesis from the above phenolic compounds with dimethoxyp-xylene, bis(methoxymethyl)biphenyl, etc. Examples of phenol curing agents include aralkyl-type phenolic resins such as phenol aralkyl resins and naphthol aralkyl resins, and biphenyl aralkyl-type phenolic resins; phenolic resins modified with paraxylylene or metaxylylene; melamine-modified phenolic resins; terpene-modified phenolic resins; dicyclopentadiene-type phenolic resins and dicyclopentadiene-type naphthol resins synthesized by copolymerization of the above phenolic compound and dicyclopentadiene; cyclopentadiene-modified phenolic resins; polycyclic aromatic ring-modified phenolic resins; biphenyl-type phenolic resins; triphenylmethane-type phenolic resins obtained by condensation or co-condensation of the above phenolic compound and aromatic aldehyde compounds such as benzaldehyde and salicylaldehyde under an acidic catalyst; and phenolic resins obtained by copolymerizing two or more of these. These phenol curing agents may be used individually or in combination of two or more.

[0041] From the viewpoint of suppressing a decrease in the glass transition temperature of the cured product, the phenol curing agent preferably contains a novolac-type phenolic resin. The proportion of the novolac-type phenolic resin content to the total amount of curing agent is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more. Furthermore, from the viewpoint of balancing various properties such as elastic modulus, fluidity, heat resistance, and moldability, the proportion of the novolac-type phenolic resin content to the total amount of curing agent may be 100% by mass, 98% by mass or less, 95% by mass or less, or 93% by mass or less.

[0042] From the viewpoint of improving compatibility with specific maleimide compounds, it is preferable to include a biphenylaralkyl type phenol resin. The proportion of the biphenylaralkyl type phenol resin content to the total amount of curing agent is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more. Furthermore, from the viewpoint of balancing various properties such as elastic modulus, fluidity, heat resistance, and moldability, the proportion of the biphenylaralkyl type phenol resin content to the total amount of curing agent may be 100% by mass, 98% by mass or less, 95% by mass or less, or 93% by mass or less.

[0043] From the viewpoint of further increasing the glass transition temperature of the sealed portion formed by curing, it is preferable to include a triphenylmethane-type phenolic resin. The proportion of the triphenylmethane-type phenolic resin content to the total amount of curing agent is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more. Furthermore, from the viewpoint of balancing various properties such as elastic modulus, fluidity, heat resistance, and moldability, the proportion of the triphenylmethane-type phenolic resin content to the total amount of curing agent may be 100% by mass, 98% by mass or less, 95% by mass or less, or 93% by mass or less.

[0044] From the viewpoint of further increasing the glass transition temperature of the sealed portion formed by curing, it is preferable to include a naphthalene-type phenolic resin. The proportion of the triphenylmethane-type phenolic resin content to the total amount of curing agent is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more. Furthermore, from the viewpoint of balancing various properties such as elastic modulus, fluidity, heat resistance, and moldability, the proportion of the triphenylmethane-type phenolic resin content to the total amount of curing agent may be 100% by mass, preferably 98% by mass or less, more preferably 95% by mass or less, and even more preferably 93% by mass or less.

[0045] The functional group equivalent of the curing agent (hydroxyl group equivalent in the case of a phenol curing agent) is not particularly limited. From the viewpoint of balancing various properties such as moldability, reflow resistance, and electrical reliability, it is preferably 70 g / eq to 1000 g / eq, and more preferably 80 g / eq to 500 g / eq. The functional group equivalent of the curing agent (hydroxyl group equivalent in the case of a phenol curing agent) shall be the value measured by the method in accordance with JIS K 0070:1992.

[0046] If the curing agent is solid, its softening point or melting point is not particularly limited. From the viewpoint of moldability and reflow resistance, it is preferably 40°C to 180°C, and from the viewpoint of handling during the manufacture of the resin composition, it is more preferably 50°C to 130°C. The melting point or softening point of the curing agent shall be a value measured in the same manner as the melting point or softening point of the epoxy resin.

[0047] The mixing ratio of epoxy resin to curing agent is not particularly limited. From the viewpoint of minimizing unreacted components, it is preferable that the ratio of the number of functional groups of the curing agent to the number of epoxy groups of the epoxy resin (number of epoxy groups of epoxy resin / number of functional groups of curing agent) be set in the range of 0.5 to 2.0, more preferably in the range of 0.6 to 1.3, and even more preferably in the range of 0.8 to 1.2.

[0048] (Curing accelerator) The resin composition may contain a curing accelerator. The type of curing accelerator is not particularly limited and can be selected according to the type of epoxy resin, the desired properties of the resin composition, etc. Examples of curing accelerators include diazabicycloalkenes such as 1,5-diazabicyclo[4.3.0]nonene-5 (DBN) and 1,8-diazabicyclo[5.4.0]undecene-7 (DBU), cyclic amidine compounds such as 2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, and 2-heptadecylimidazole; derivatives of the cyclic amidine compounds; phenol novolac salts of the cyclic amidine compounds or their derivatives; and quinone compounds such as maleic anhydride, 1,4-benzoquinone, 2,5-toluquinone, 1,4-naphthoquinone, 2,3-dimethylbenzoquinone, 2,6-dimethylbenzoquinone, 2,3-dimethoxy-5-methyl-1,4-benzoquinone, 2,3-dimethoxy-1,4-benzoquinone, and phenyl-1,4-benzoquinone. Compounds having intramolecular polarization obtained by adding compounds with π bonds, such as zophenylmethane; cyclic amidinium compounds such as tetraphenylborate salt of DBU, tetraphenylborate salt of DBN, tetraphenylborate salt of 2-ethyl-4-methylimidazole, and tetraphenylborate salt of N-methylmorpholine; tertiary amine compounds such as pyridine, triethylamine, triethylenediamine, benzyldimethylamine, triethanolamine, dimethylaminoethanol, and tris(dimethylaminomethyl)phenol; derivatives of the above tertiary amine compounds; ammonium salt compounds such as tetra-n-butylammonium acetate, tetra-n-butylammonium phosphate, tetraethylammonium acetate, tetra-n-hexylammonium benzoate, and tetrapropylammonium hydroxide;Triphenylphosphine, tributylphosphine, diphenyl(p-tolyl)phosphine, tris(alkylphenyl)phosphine, tris(alkoxyphenyl)phosphine, tris(alkyl-alkoxyphenyl)phosphine, tris(dialkylphenyl)phosphine, tris(trialkylphenyl)phosphine, tris(tetraalkylphenyl)phosphine, tris(dialkoxyphenyl)phosphine, tris(trialkoxyphenyl)phosphine, tris(tetraalkoxyphenyl)phosphine, tris(tetraalkoxyphenyl)phosphine, and other trialkylphosphines Tertiary phosphines such as phosphates, dialkylarylphosphines, and alkyldiarylphosphines; phosphine compounds such as complexes of the tertiary phosphines with organoborons; quinone compounds such as maleic anhydride, 1,4-benzoquinone, 2,5-tholquinone, 1,4-naphthoquinone, 2,3-dimethylbenzoquinone, 2,6-dimethylbenzoquinone, 2,3-dimethoxy-5-methyl-1,4-benzoquinone, 2,3-dimethoxy-1,4-benzoquinone, phenyl-1,4-benzoquinone, and diazophenylmethyl Compounds having intramolecular polarization obtained by adding compounds having π bonds, such as tang; the tertiary phosphine or the phosphine compound and 4-bromophenol, 3-bromophenol, 2-bromophenol, 4-chlorophenol, 3-chlorophenol, 2-chlorophenol, 4-iodidephenol, 3-iodidephenol, 2-iodidephenol, 4-bromo-2-methylphenol, 4-bromo-3-methylphenol, 4-bromo-2,6-dimethylphenol, 4-bromo-3,5-dimethylphenol, 4-bromo-2,6-di-ter Compounds with intramolecular polarization obtained by reacting halogenated phenol compounds such as t-butylphenol, 4-chloro-1-naphthol, 1-bromo-2-naphthol, 6-bromo-2-naphthol, and 4-bromo-4'-hydroxybiphenyl, followed by a dehalogenation step; tetrasubstituted phosphoniums such as tetraphenylphosphonium, tetrasubstituted phosphoniums and tetrasubstituted borates without phenyl groups bonded to the boron atom such as tetra-p-tolylborate; and salts of tetraphenylphosphonium and phenol compounds.

[0049] When the resin composition contains a curing accelerator, the amount is preferably 0.1 to 30 parts by mass, and more preferably 1 to 15 parts by mass, per 100 parts by mass of the resin components (total of epoxy resin, specific maleimide compound, and curing agent; the same applies hereinafter). When the amount of curing accelerator is 0.1 parts by mass or more per 100 parts by mass of the resin components, it tends to cure well in a short time. When the amount of curing accelerator is 30 parts by mass or less per 100 parts by mass of the resin components, it tends to result in a good molded product with a curing speed that is not too fast.

[0050] (Inorganic Fillers) The resin composition may contain inorganic fillers. The type of inorganic filler is not particularly limited and can be selected from those commonly used in resin compositions. Specifically, examples of inorganic materials include fused silica, crystalline silica, glass, alumina, calcium carbonate, zirconium silicate, calcium silicate, silicon nitride, aluminum nitride, boron nitride, beryllia, zirconia, zircon, fossterite, steatite, spinel, mullite, titania, talc, clay, and mica. Inorganic fillers with flame retardant properties may also be used. Examples of inorganic fillers with flame retardant properties include aluminum hydroxide, magnesium hydroxide, composite metal hydroxides such as magnesium and zinc hydroxide, and zinc borate.

[0051] Among inorganic fillers, silica such as fused silica is preferred from the viewpoint of reducing the coefficient of thermal expansion, and alumina is preferred from the viewpoint of high thermal conductivity. One type of inorganic filler may be used alone, or two or more types may be used in combination.

[0052] The content of inorganic fillers in the resin composition is not particularly limited. From the viewpoint of fluidity and strength, the content of inorganic fillers is preferably 30% to 90% by volume of the total resin composition, and more preferably 50% to 85% by volume. When the content of inorganic fillers is 30% or more by volume of the total resin composition, the properties such as the coefficient of thermal expansion, thermal conductivity, and elastic modulus of the cured product tend to improve further. When the content of inorganic fillers is 90% or less by volume of the total resin composition, the increase in viscosity of the resin composition is suppressed, the fluidity improves further, and the moldability tends to be better.

[0053] Furthermore, from the viewpoint of fluidity and strength, the inorganic filler content is preferably 70% to 90% by mass of the total resin composition, and may be 75% to 90% by mass. When the inorganic filler content is 70% by mass or more of the total resin composition, the properties of the cured product, such as the coefficient of thermal expansion, thermal conductivity, and elastic modulus, tend to improve further. When the inorganic filler content is 90% by mass or less of the total resin composition, the increase in viscosity of the resin composition is suppressed, fluidity improves further, and moldability tends to be better.

[0054] When the inorganic filler is in particulate form, its average particle size is not particularly limited. For example, the overall volume-average particle size of the inorganic filler is preferably 0.2 μm to 10 μm, and more preferably 0.5 μm to 5 μm. When the volume-average particle size is 0.2 μm or more, the increase in viscosity of the resin composition tends to be further suppressed. When the volume-average particle size is 10 μm or less, the ability to fill narrow gaps tends to be further improved. The volume-average particle size of the inorganic filler can be measured as the volume-average particle size (D50) using a laser scattering diffraction particle size distribution analyzer.

[0055] (Coupling agent) The resin composition may contain a coupling agent. Examples of known coupling agents include silane compounds such as epoxysilane, mercaptosilane, aminosilane, alkylsilane, ureidosilane, and vinylsilane, as well as titanium compounds, aluminum chelate compounds, and aluminum / zirconium compounds.

[0056] From the viewpoint of further suppressing peeling of the cured and formed sealing portion from the substrate, it is preferable to include a sulfur-containing coupling agent. Examples of sulfur-containing coupling agents include coupling agents having a mercapto group and coupling agents having a sulfide group, specifically, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, tetrasulfideditriethoxysilane, and the like.

[0057] When the coupling agent includes a sulfur-containing coupling agent, the amount of the sulfur-containing coupling agent is preferably 1% by mass or more, more preferably 3% by mass or more, and even more preferably 5% by mass or more, relative to the total amount of the coupling agent. Furthermore, when the coupling agent includes a sulfur-containing coupling agent, from the viewpoint of balancing various properties such as elastic modulus and moldability, the amount of the sulfur-containing coupling agent is preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 35% by mass or less, relative to the total amount of the coupling agent.

[0058] From the viewpoint of increasing the strength of the sealed portion formed by curing, the coupling agent is preferably a benzene ring-containing coupling agent. The amount of the benzene ring-containing coupling agent is preferably 40% by mass or more, more preferably 50% by mass or more, and even more preferably 60% by mass or more, based on the total amount of the coupling agent. Furthermore, when the coupling agent contains a benzene ring-containing coupling agent, from the viewpoint of balancing various properties, the amount of the benzene ring-containing coupling agent is preferably 80% by mass or less, more preferably 75% by mass or less, and even more preferably 70% by mass or less, based on the total amount of the coupling agent.

[0059] If the resin composition contains a coupling agent, the amount of the coupling agent is preferably 0.05 to 5 parts by mass, and more preferably 0.1 to 2.5 parts by mass, per 100 parts by mass of the inorganic filler.

[0060] (Release Agent) The resin composition may contain a release agent from the viewpoint of obtaining good release properties from the mold during molding. The release agent is not particularly limited, and conventionally known ones can be used. Specifically, examples include carnauba wax, higher fatty acids such as montanic acid and stearic acid, higher fatty acid metal salts, ester waxes such as montanic acid esters, and polyolefin waxes such as oxidized polyethylene and non-oxidized polyethylene. The release agent may be used alone or in combination of two or more types.

[0061] If the resin composition contains a release agent, the amount is preferably 0.01 to 10 parts by mass, and more preferably 0.1 to 5 parts by mass, per 100 parts by mass of the resin component. When the amount of release agent is 0.01 parts by mass or more per 100 parts by mass of the resin component, sufficient release properties tend to be obtained. When it is 10 parts by mass or less, better adhesion tends to be obtained.

[0062] (Colorants) The resin composition may further contain colorants. Examples of known colorants include carbon black, organic dyes, organic pigments, titanium dioxide, red lead, and red iron oxide. The amount of colorant can be appropriately selected depending on the purpose. One colorant may be used alone, or two or more colorants may be used in combination.

[0063] (Stress Relief Agent) The resin composition may contain stress relief agents such as silicone oil and silicone rubber particles. Including stress relief agents can further reduce package warping deformation and package cracking. Examples of stress relief agents include commonly used and known stress relief agents (flexible agents). Specifically, these include thermoplastic elastomers such as silicone-based, styrene-based, olefin-based, urethane-based, polyester-based, polyether-based, polyamide-based, and polybutadiene-based; rubber particles such as NR (natural rubber), NBR (acrylonitrile-butadiene rubber), acrylic rubber, urethane rubber, and silicone powder; and rubber particles having a core-shell structure such as methyl methacrylate-styrene-butadiene copolymer (MBS), methyl methacrylate-silicone copolymer, and methyl methacrylate-butyl acrylate copolymer. One type of stress relief agent may be used alone, or two or more types may be used in combination.

[0064] (Ion exchanger) The resin composition may contain an ion exchanger. In particular, when the resin composition is used as a molding material for sealing, it is preferable to contain an ion exchanger from the viewpoint of improving the moisture resistance and high-temperature storage characteristics of an electronic component device provided with an element to be sealed. The ion exchanger is not particularly limited, and conventionally known ones can be used. Specifically, hydrotalcite compounds, and hydrated oxides of at least one element selected from the group consisting of magnesium, aluminum, titanium, zirconium, and bismuth can be mentioned. The ion exchanger may be used alone or in combination of two or more. Among them, hydrotalcite represented by the following general formula (A) is preferable.

[0065] Mg （１－Ｘ） Al Ｘ (OH) ２ (CO ３ ) Ｘ／２ ・mH ２ O …… (A) (0 < X ≤ 0.5, m is a positive number)

[0066] When the resin composition contains an ion exchanger, its content is not particularly limited as long as it is sufficient to capture ions such as halogen ions. For example, it is preferably 0.1 part by mass to 30 parts by mass, and more preferably 1 part by mass to 5 parts by mass with respect to 100 parts by mass of the resin component.

[0067] (Flame retardant) The resin composition may contain a flame retardant. The flame retardant is not particularly limited, and conventionally known ones can be used. Specifically, organic or inorganic compounds containing a halogen atom, an antimony atom, a nitrogen atom, or a phosphorus atom, metal hydroxides, etc. can be mentioned. The flame retardant may be used alone or in combination of two or more.

[0068] When the resin composition contains a flame retardant, its amount is not particularly limited as long as it is sufficient to obtain a desired flame retardant effect. For example, it is preferably 1 part by mass to 30 parts by mass, and more preferably 2 parts by mass to 15 parts by mass with respect to 100 parts by mass of the resin component.

[0069] <Method for preparing the resin composition> The method for preparing the resin composition is not particularly limited. A common method is to thoroughly mix predetermined amounts of components using a mixer or the like, then melt-knead them using a mixing roll, extruder or the like, cool them, and pulverize them. More specifically, for example, a method can be used in which predetermined amounts of the above-mentioned components are uniformly stirred and mixed, then kneaded using a kneader, roll, extruder or the like that has been preheated to 70°C to 140°C, then cooled, and pulverized.

[0070] The resin composition is preferably solid at room temperature and atmospheric pressure (for example, 25°C and atmospheric pressure). The shape of the resin composition when it is solid is not particularly limited and may be in the form of powder, granules, tablets, etc.

[0071] <Physical Properties> (Glass Transition Temperature) The glass transition temperature of the cured resin composition is preferably 180°C or higher, more preferably 190°C or higher, and even more preferably 200°C or higher. A higher glass transition temperature of the cured product is desirable.

[0072] The glass transition temperature of a cured resin composition is determined by performing dynamic viscoelasticity measurements in tensile mode. The temperature at which tanδ is maximized in the relationship diagram between the obtained temperature and tanδ is defined as the glass transition temperature.

[0073] (Measurement of flexural strength) The cured resin composition preferably has a flexural strength of 110 MPa or more at 25°C, more preferably 120 MPa or more, even more preferably 130 MPa or more, and particularly preferably 140 MPa or more. There is no particular upper limit to the flexural strength.

[0074] The cured resin composition preferably has a flexural strength of 10 MPa or more at 260°C, more preferably 15 MPa or more, and even more preferably 20 MPa or more. There is no particular upper limit to the flexural strength.

[0075] The flexural strength of the cured resin composition is determined by performing a bending test at 25°C or 260°C using a Tensilon universal material testing machine. A bending stress-displacement curve is created from equation (A), and the maximum stress is defined as the flexural strength (MPa).

[0076] σ = 3FL / 2bh ２ ...Formula (A) σ: Bending stress (MPa) F: Bending load (N) L: Distance between supports (mm) b: Specimen width (mm) h: Specimen thickness (mm)

[0077] (Flexural modulus) The cured resin composition preferably has a flexural modulus of 25 GPa or less at 25°C, more preferably 23 GPa or less, and even more preferably 21 GPa or less.

[0078] The cured resin composition preferably has a flexural modulus of 5.0 GPa or less, more preferably 4.0 GPa or less, and even more preferably 3.5 GPa or less at 260°C.

[0079] The flexural modulus of the cured resin composition is determined by preparing test specimens according to JIS K7171:2016 and performing a three-point bending test.

[0080] (Shear Adhesion) The cured resin composition preferably has a shear adhesion strength to nickel at 25°C of 3 MPa or more, more preferably 4 MPa or more, and even more preferably 6 MPa or more. There is no particular upper limit to the shear adhesion strength to nickel at 25°C.

[0081] The cured resin composition preferably has a shear adhesion strength to nickel at 260°C of 0.5 MPa or more, more preferably 0.8 MPa or more, and even more preferably 1.0 MPa or more. There is no particular upper limit to the shear adhesion strength to nickel at 260°C.

[0082] The shear adhesion strength of the cured resin composition is measured using a bond tester at a shear rate of 50 μm / s.

[0083] (Uses of the resin composition) The resin composition of this disclosure can be used for encapsulation and is particularly suitable for encapsulating semiconductor devices, and is especially suitable for encapsulating power semiconductor devices in power semiconductor modules. However, since the resin composition of this disclosure prevents peeling from nickel substrates, it may be used for other purposes as well.

[0084] <Power Semiconductor Device> The power semiconductor device of the present disclosure comprises, in this order, a power semiconductor element, an insulating substrate, and a heat dissipation member, wherein the power semiconductor element is sealed with a cured product of the resin composition of the present disclosure, and the insulating substrate and the heat dissipation member are bonded together.

[0085] Common power semiconductor elements can be used. Insulating substrates can be common ones used in power semiconductor devices. For example, ceramic substrates such as alumina, aluminum nitride, and silicon nitride can be used as insulating substrates. Heat dissipation members may be heat sinks, heat spreaders, cooling members, etc. Heat dissipation members may be made of metals such as aluminum and copper.

[0086] Figure 1 is a schematic cross-sectional view showing an example of a power semiconductor device. Specific examples of power semiconductor devices will be described with reference to Figure 1, but this disclosure is not limited thereto. Furthermore, the sizes of the components in Figure 1 are conceptual, and the relative relationships between the components are not limited thereto.

[0087] The power semiconductor element 2 is placed on a substrate 4 made of copper or the like, and the power semiconductor element 2 and the substrate 4 are connected by a coupling portion 8. The chips are connected by wires 6. The wires 6 may be replaced with other conductive members such as busbars. An insulating layer 10 is placed on the side of the substrate 4 opposite to the power semiconductor element 2, and a substrate 12 made of nickel or the like is provided on the other side of the insulating layer 10. The power semiconductor module including these is sealed as a whole with a sealing material to form a sealing portion 14. Methods for forming the sealing portion 14 include transfer molding and compression molding. The substrate 12 is connected to a heat dissipation member 16, and a coupling portion 18 is formed between them. The coupling portions 8 and 18 may be joined by sintering or by soldering. Examples of sintering methods include silver sintering and copper sintering from the viewpoint of thermal conductivity.

[0088] The present disclosure will be described in detail below with reference to examples, but the scope of the present disclosure is not limited to these examples.

[0089] (Preparation of Resin Composition) The components shown below were blended in the proportions (parts by mass) shown in Table 1 or Table 2, and roll kneading was performed at a kneading temperature of 80°C for a kneading time of 10 minutes to prepare the resin composition.

[0090]

[0091]

[0092] The details of each component shown in the table are as follows: • Epoxy resin A: Triphenylmethane type epoxy resin (epoxy equivalent: 169 g / eq) • Epoxy resin B: Thioether type epoxy resin (epoxy equivalent: 244 g / eq) • Epoxy resin C: Biphenyl aralkyl type epoxy resin (epoxy equivalent: 207 g / eq) • Epoxy resin D: Naphthalene type epoxy resin (epoxy equivalent: 163-170 g / eq)

[0093] • Curing agent A: Biphenyl aralkyl type phenol resin (hydroxyl group equivalent: 199 g / eq) • Curing agent B: Biphenyl aralkyl type phenol resin (hydroxyl group equivalent: 132 g / eq) • Curing agent C: Triphenylmethane type phenol resin (hydroxyl group equivalent: 104 g / eq) • Curing agent D: Naphthol aralkyl resin (hydroxyl group equivalent: 215 g / eq) • Curing agent E: Phenol novolac resin (hydroxyl group equivalent: 106 g / eq) • Curing accelerator A: 4-methyl-2-phenylimidazole

[0094] Maleimide compound A: 4,4'-diphenylmethanedimaleimide; Maleimide compound B: Biphenylaralkyl-type maleimide resin (compound represented by formula (II))

[0095] • Coupling agent A: N-phenyl-3-aminopropyltrimethoxysilane • Coupling agent B: 3-mercaptopropyltrimethoxysilane • Coupling agent C: Tetrasulfide ditriethoxysilane • Release agent A: Carnauba wax • Release agent B: Mixture of linear polyethylene oxide and phenol novolac resin • Coloring agent: Carbon black • Adhesion additive A: Gallic acid • Inorganic filler A: Spherical fused silica (volume average particle size: 20 μm) • Inorganic filler B: Spherical fused silica (volume average particle size: 0.5 μm)

[0096] (Preparation of cured specimens for measurement) Cured specimens for measuring glass transition temperature, flexural strength, flexural modulus, and water absorption were obtained as follows: The resin composition was molded in a transfer molding machine under the conditions of a mold temperature of 175°C, a molding pressure of 6.9 MPa, and a curing time of 120 seconds. Subsequently, the molded material was post-cured at 175°C for 5 hours to obtain a cured specimen. For each measurement, a specific shape was cut from the cured specimen to serve as the test specimen.

[0097] (Measurement of Glass Transition Temperature) The cured material was cut into strips measuring 2 mm × 0.5 mm × 40 mm to prepare test specimens for evaluating the glass transition temperature. The glass transition temperature of the test specimens was calculated by performing dynamic viscoelasticity measurements in tensile mode. The measurement conditions were a frequency of 10 Hz, a heating rate of 5 °C / min, and a strain of 0.1%. In the relationship diagram between the obtained temperature and tanδ, the temperature at which tanδ was maximum was considered to be the glass transition temperature. An RSA-G2 (TA Instruments Corporation) was used as the evaluation device.

[0098] (Measurement of Bending Strength) The hardened material was cut into pieces measuring 4.0 mm × 10.0 mm × 80 mm to prepare test specimens for evaluating bending strength. The obtained test specimens were subjected to bending tests at 25°C or 260°C under the conditions of a support distance of 64 mm, a crosshead speed of 10 mm / min, and a temperature of 25°C using a Tensilon universal material testing machine (Instron 5948, Instron Corporation). Using the measured results, a bending stress-displacement curve was created from the above formula (A), and the maximum stress was defined as the bending strength (MPa).

[0099] (Measurement of flexural modulus) Test specimens were prepared according to JIS K7171 (2016), and the flexural modulus (GPa) at 25°C or 260°C was determined by three-point bending measurement. A Tensilon (A&D Company, Limited) evaluation device was used.

[0100] (Measurement of Water Absorption Rate) A disc-shaped molded object (50 mm in diameter x 3 mm in thickness) was prepared for measuring the water absorption rate. This was placed in a pressure cooker test apparatus at 121°C / 2.1 atm, removed after 24 hours, and the percentage increase in mass from the mass immediately before placement was calculated. Subsequently, the mass of the test piece was measured and the water absorption rate was calculated based on the following formula: Water absorption rate (%) = {(Mass after storage - Mass before storage) / Mass after storage} × 100

[0101] (Measurement of shear adhesion strength) The resin composition was molded onto a nickel plate using a transfer molding machine under the following conditions: mold temperature of 175°C, molding pressure of 6.9 MPa, and curing time of 120 seconds, to a size of 4 mm in base diameter, 3 mm in top diameter, and 4 mm in height. Subsequently, the molded product was post-cured at 175°C for 5 hours to obtain test specimens for adhesion strength measurement. The shear adhesion strength (MPa) of the obtained test specimens was determined using a bond tester (Nordson Advanced Technologies, Inc., Series 4000) at room temperature (25°C) or while maintaining the nickel plate temperature at 260°C, at a shear rate of 50 μm / s.

[0102]

[0103]

[0104] When comparing epoxy resins and curing agents of the same type, Example 1, which contains the specific maleimide compound, showed higher shear adhesion to nickel at both room temperature (25°C) and high temperature (260°C) compared to Reference Example 1, which does not contain the specific maleimide compound. Similarly, Example 2 showed higher shear adhesion to nickel compared to Comparative Example 1, Example 3 compared to Reference Example 2, Example 4 compared to Comparative Example 2 and Reference Example 2, Example 5 compared to Comparative Example 3 and Reference Example 3, and Example 6 compared to Reference Example 4. Thus, in situations where the use of the same type of resin system is desired, adding the specific maleimide compound exhibits the excellent effect of improving shear adhesion to nickel. Furthermore, even when the equivalent ratio (phenol group / epoxy group) was changed, Example 7, which contains the specific maleimide compound, showed higher shear adhesion to nickel at both room temperature (25°C) and high temperature (260°C) compared to Comparative Example 4, which does not contain the specific maleimide compound. Furthermore, in Example 8, where the amount of the specific maleimide compound was increased compared to Example 7, the shear adhesion strength to nickel was higher than that of Comparative Example 4, which did not contain the specific maleimide, at both room temperature (25°C) and high temperature (260°C). It should be noted that a low water absorption rate is desirable, as a high water absorption rate of the cured product (sealed portion) can cause delamination when heated to high temperatures in a reflow oven. In all examples, the water absorption rate was equivalent to or lower than that of the corresponding reference example and comparative example.

[0105] 2 Power semiconductor element 4, 12 Substrate 6 Wire 8, 18 Joint 10 Insulating layer 14 Sealing part 16 Heat dissipation member

Claims

1. A sealing resin composition containing an epoxy resin, a maleimide compound having a biphenyl structure, and a curing agent.

2. The encapsulating resin composition according to claim 1, wherein the total content of the maleimide compound having the biphenyl structure is 30% by mass or more relative to the content of the epoxy resin.

3. The encapsulating resin composition according to claim 1 or claim 2, comprising a sulfur-containing compound.

4. The encapsulating resin composition according to claim 1 or claim 2, wherein the curing agent comprises a phenolic resin.

5. The encapsulation resin composition according to claim 1 or claim 2, for use in encapsulating power semiconductor devices.

6. A power semiconductor device comprising a power semiconductor element, an insulating substrate, and a heat dissipation member in this order, wherein the power semiconductor element is sealed with a cured product of the sealing resin composition described in claim 1 or claim 2.

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