Sealing resin composition and semiconductor module

Abstract

This sealing resin composition comprises a curable resin component, an inorganic filler, an elastomer component, and a maleimide compound.

Description

Encapsulating resin composition and semiconductor module

[0001] The present invention relates to an encapsulating resin composition and a semiconductor module.

[0002] BACKGROUND ART Resin compositions containing a curable resin component such as an epoxy resin are widely used as materials (encapsulants) for encapsulating electronic components such as transistors and ICs (integrated circuits).

[0003] In recent years, the demand for power semiconductors used to control power sources has increased with the spread of electric vehicles. However, because power semiconductors generally generate a large amount of heat, there is a demand for improved heat resistance in the encapsulating materials used for them.

[0004] As a technique for improving the heat dissipation of power semiconductors that operate at high temperatures, a method is known in which a metal circuit board and a metal cooler of a module are joined by sintering with heat and pressure or with heat and pressure using a metal adhesive. Patent Document 1 describes joining the metal circuit board and the metal cooler via a heat dissipation sheet using a joining layer formed by sintering a sintering paste containing metal particles such as silver particles and copper particles.

[0005] Furthermore, Patent Document 1 describes a resin composition used to seal a power semiconductor element, a bonding layer, a circuit board, and a heat dissipation sheet, and a power module including a sealing material of the resin composition.

[0006] JP 2022-98698 A

[0007] The power module described in Patent Document 1 is composed of multiple components, such as a power semiconductor element, a metal circuit board, and a metal cooler. Therefore, there is a problem in that the bonding layer (e.g., sintered layer) bonding the metal circuit board and the metal cooler is likely to peel off due to expansion of the components during sintering and contraction of the components when cooled to room temperature. It is desirable for the power module to be able to suppress peeling of the bonding layer. For example, an encapsulating resin composition that can reduce stress applied to the entire module during heating or cooling and that can produce an encapsulating material that can suppress peeling of the bonding layer is desirable.

[0008] In view of the above circumstances, the present disclosure aims to provide an encapsulating resin composition that can reduce stress applied to the entire module when heated or cooled and that can produce an encapsulating material that can suppress peeling of the bonding layer, and a semiconductor module that includes an encapsulating material formed from this resin composition.

[0009] <1> An encapsulating resin composition comprising a curable resin component, an inorganic filler, an elastomer component, and a maleimide compound. <2> The encapsulating resin composition according to <1>, wherein the elastomer component is liquid, solid, or particulate, and the elastomer component contains a compound having a siloxane bond. <3> The encapsulating resin composition according to <2>, wherein the compound having a siloxane bond contains a compound having a structural unit represented by the following formula (1):

[0010]

[0011] [In formula (1), R １ and R ２are each independently selected from the group consisting of an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a monovalent organic group having an epoxy group, a monovalent organic group having a carboxy group, and a polyalkylene ether group having 3 to 500 carbon atoms.] <4> The encapsulating resin composition according to <2> or <3>, wherein the compound having a siloxane bond includes a compound having at least one bond selected from an epoxy group and an ether bond in a side chain. <5> The encapsulating resin composition according to any one of <1> to <4>, wherein the curable resin component includes an epoxy resin and a curing agent. <6> The encapsulating resin composition according to <5>, wherein the curing agent includes a phenolic curing agent. <7> The encapsulating resin composition according to any one of <1> to <6>, which is used as an encapsulant for electronic component devices. <8> A semiconductor module comprising: a circuit board; a semiconductor element provided on one surface of the circuit board; a first bonding layer bonding the semiconductor element to the circuit board; a cooler provided on a surface of the circuit board opposite to the surface on which the semiconductor element is provided; a second bonding layer bonding the circuit board to the cooler; and an encapsulant covering the semiconductor element, the first bonding layer, and the circuit board, wherein the encapsulant comprises a cured product of the encapsulating resin composition according to any one of <1> to <7>.

[0012] According to the present invention, it is possible to provide an encapsulating resin composition that can be used to produce an encapsulating material that can reduce the stress applied to the entire module when heated or cooled and can suppress peeling of the bonding layer, and a semiconductor module that includes an encapsulating material formed from this resin composition.

[0013] 1 is a cross-sectional view schematically illustrating a power module 10 that is an example of a semiconductor module according to the present disclosure.

[0014] Hereinafter, embodiments for carrying out the present invention will be described in detail. However, the present invention is not limited to the following embodiments. In the following embodiments, components (including element steps, etc.) are not essential unless otherwise specified. The same applies to numerical values ​​and their ranges, and do not limit the present invention.

[0015] In the present disclosure, the term "process" includes not only processes that are independent of other processes, but also processes that cannot be clearly distinguished from other processes as long as the purpose of the process is achieved. In the present disclosure, numerical ranges indicated using "to" include the numerical values ​​before and after "to" as the minimum and maximum values, respectively. In numerical ranges described in stages in the present disclosure, the upper or lower limit value described in one numerical range may be replaced with the upper or lower limit value of another staged numerical range. Furthermore, in numerical ranges described in the present disclosure, the upper or lower limit value of that numerical range may be replaced with a value shown in the examples. In the present disclosure, each component may contain multiple corresponding substances. When multiple substances 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 substances present in the composition, unless otherwise specified. In the present disclosure, each component may contain multiple types of particles. When multiple types of particles corresponding to each component are present in the composition, the particle size of each component means the value for a mixture of the multiple types of particles present in the composition, unless otherwise specified.

[0016] [Encapsulating Resin Composition] The encapsulating resin composition of the present disclosure is a composition containing a curable resin component, an inorganic filler, an elastomer component, and a maleimide compound.

[0017] The encapsulating resin composition is expected to be used as an encapsulating material to cover a semiconductor element, a bonding layer, and a circuit board when a semiconductor module is formed by sinter-bonding a circuit board, which is bonded to a semiconductor element via a bonding layer, and a cooler using a metal fine powder. In this case, if the encapsulating material has a high elastic modulus and large thermal expansion, peeling of the bonding layer (e.g., a sintered layer) between the circuit board and the cooler is likely to occur. One method for reducing the elastic modulus of the encapsulating material and suppressing warpage of the module is to add an elastomer component to the encapsulating resin composition. The inclusion of the elastomer component in the encapsulating resin composition relatively reduces the proportion of the curable resin component. As a result, it is believed that an encapsulating resin composition can be obtained that has low elasticity while suppressing an increase in the thermal expansion coefficient, and has excellent warpage suppression effects.

[0018] However, when an elastomer component is used, the strength and heat resistance of the encapsulant decrease, making it difficult to suppress peeling of the bonding layer. On the other hand, the use of a maleimide compound in combination improves the flexural strength and elastic modulus of the encapsulant, making it possible to suppress peeling of the bonding layer. Here, if the amount of inorganic filler in the encapsulating resin composition is increased, adding a maleimide compound to the composition can improve the flexural strength and elastic modulus, but this increases the load on the module, which may further increase peeling of the bonding layer. In the encapsulating resin composition of the present disclosure, the use of an elastomer component in combination with a maleimide compound can more effectively suppress peeling of the bonding layer, even when the amount of inorganic filler is increased to increase the load on the module.

[0019] The encapsulating resin composition may be solid or liquid at room temperature and normal pressure (for example, 25°C, atmospheric pressure). When the encapsulating resin composition is solid, it may be in the form of a powder, tablet, or the like. When the encapsulating resin composition is in the form of a tablet, it is preferable from the viewpoint of handleability that the dimensions and mass of the tablet-shaped encapsulating resin composition are set to dimensions and mass that are suitable for the molding conditions of the package. Each component of the encapsulating resin composition will be described below, but the encapsulating resin composition of the present disclosure is not limited thereto.

[0020] The encapsulating resin composition can be applied to, for example, the production of electronic component devices, particularly power devices, which will be described later. The encapsulating resin composition may be used as an encapsulant for electronic component devices, or may be used to encapsulate electronic components in power devices.

[0021] <Elastomer Component> The type of elastomer component is not particularly limited. Specific examples of the elastomer component include compounds having a siloxane bond (Si—O—Si) in the molecule (hereinafter also referred to as siloxane compounds), styrene-based elastomers, olefin-based elastomers, urethane-based elastomers, polyester-based elastomers, polyether-based elastomers, polyamide-based elastomers, polybutadiene-based elastomers, organic phosphorus compounds such as triphenylphosphine oxide and phosphate esters, 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. The elastomer component may be used alone or in combination of two or more.

[0022] From the viewpoint of stress relaxation, the elastomer component preferably contains a compound having a siloxane bond (hereinafter also referred to as "siloxane compound"). From the viewpoint of handleability, the elastomer component preferably contains a styrene-based elastomer, and more preferably contains an indene-styrene-coumarone copolymer. Furthermore, a siloxane compound and a styrene-based elastomer may be used in combination as the elastomer component. When a siloxane compound and a styrene-based elastomer are used in combination, the content of the siloxane compound relative to the entire elastomer component may be, for example, 20% to 80% by mass, and preferably 30% to 70% by mass. Alternatively, the content of the siloxane compound relative to the entire elastomer component may be 50% to 100% by mass, 70% to 100% by mass, or 90% to 100% by mass. The elastomer component may be in any of a liquid, solid, or particulate form.

[0023] In the present disclosure, when an elastomer component is a compound that also corresponds to a curable resin component (for example, when the elastomer component has a functional group that causes a curing reaction, such as an epoxy group), the compound is classified as an elastomer component. An elastomer component refers to a component that has little effect on the resin crosslinking reaction but relieves the stress of the entire resin, and refers to a component that has a functional group equivalent of 400 g / eq or more even if it has a functional group that causes a curing reaction.

[0024] -Siloxane Compound- The molecular weight of the siloxane compound is not particularly limited. From the viewpoint of suppressing warpage of the module, the number average molecular weight of the siloxane compound is preferably 10,000 or more, and more preferably 15,000 or more. There is no particular upper limit to the number average molecular weight, but from the viewpoint of handleability, it is preferably 30,000 or less, and more preferably 20,000 or less.

[0025] In the present disclosure, the number average molecular weight (Mn) is a value measured by gel permeation chromatography (GPC) using a calibration curve based on standard polystyrene. Specifically, for example, the value is measured using a pump (Hitachi, Ltd., L-6200 model), columns (TSKgel-G5000HXL and TSKgel-G2000HXL, both manufactured by Tosoh Corporation, trade names) and a detector (Hitachi, Ltd., L-3300RI model) for GPC, using tetrahydrofuran as the eluent, at a temperature of 30°C and a flow rate of 1.0 ml / min.

[0026] From the viewpoint of suppressing warpage of the module, the siloxane compound is preferably a siloxane compound having a structural unit represented by the following formula (1).

[0027]

[0028] In formula (1), R １ and R ２ are each independently selected from the group consisting of an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a monovalent organic group having an epoxy group, a monovalent organic group having a carboxy group, and a polyalkylene ether group having 3 to 500 carbon atoms.

[0029] From the viewpoint of suppressing warpage of the module, R １ and R ２ are each independently preferably an alkyl group having 1 to 10 carbon atoms or an aryl group having 6 to 10 carbon atoms, more preferably a methyl group or a phenyl group, and even more preferably a methyl group. When a plurality of structural units represented by formula (1) are present, a plurality of R １ and multiple R ２ may be the same or different.

[0030] In the siloxane compound having the structural unit represented by formula (1), the number of structural units represented by formula (1) is not particularly limited. For example, it can be selected from the range of 1 to 200, and more preferably from the range of 5 to 150.

[0031] From the viewpoint of suppressing warpage of the module, it is preferable that the elastomer component contains, as the siloxane compound, a siloxane compound having an alkylene group having 1 to 10 carbon atoms which forms a main chain together with the structural unit represented by formula (1). Examples of siloxane compounds which contain a structural unit represented by formula (1) and an alkylene group having 1 to 10 carbon atoms which forms a main chain include siloxane compounds having a structural unit represented by formula (1) and a structural unit represented by the following formula (2):

[0032]

[0033] In formula (2), R ３ is an alkylene group having 1 to 10 carbon atoms, and preferably an alkylene group having 1 to 5 carbon atoms. When a plurality of structural units represented by formula (2) are present, a plurality of R ３ may be the same or different.

[0034] An encapsulating resin composition containing a siloxane compound having a structural unit represented by formula (1) and a structural unit represented by formula (2) not only has the effect of suppressing warpage of a module, but also tends to be less likely to cause poor appearance such as whitening of the encapsulating material surface. This is thought to be because, compared with a siloxane compound having only the structural unit represented by formula (1), a siloxane compound having a structural unit represented by formula (1) and a structural unit represented by formula (2) has better compatibility with the curable resin component, and bleeding of the siloxane compound from the encapsulating resin composition is more suppressed.

[0035] In a siloxane compound having a structural unit represented by formula (1) and a structural unit represented by formula (2), the number of structural units represented by formula (2) is not particularly limited. For example, it can be selected from the range of 2 to 400, and more preferably from the range of 3 to 300.

[0036] In a siloxane compound having a structural unit represented by formula (1) and a structural unit represented by formula (2), the mass ratio of the structural unit represented by formula (1) to the structural unit represented by formula (2) (formula (1) / formula (2)) is not particularly limited.

[0037] In a siloxane compound having a structural unit represented by formula (1) and a structural unit represented by formula (2), the arrangement of the structural unit represented by formula (1) and the structural unit represented by formula (2) is not particularly limited, and may be in a block form or random form. From the viewpoint of the effect of suppressing warpage of the module, a block form is preferable, and it is more preferable that a block consisting of the structural unit represented by formula (2), a block consisting of the structural unit represented by formula (1), and a block consisting of the structural unit represented by formula (2) are arranged in this order.

[0038] Examples of the siloxane compound having a structural unit represented by formula (1) and a structural unit represented by formula (2) include a compound having a structure represented by the following formula (3) (hereinafter also referred to as a first specific siloxane compound):

[0039]

[0040] In formula (3), n is an integer from 1 to 200, and m １ and m２ are each independently an integer of 1 to 200, and R １ and R ２ are each independently selected from the group consisting of an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a monovalent organic group having an epoxy group, a monovalent organic group having a carboxy group, and a polyalkylene ether group having 3 to 500 carbon atoms; R ３ are each independently an alkylene group having 1 to 10 carbon atoms, and R ４ are each independently a divalent hydrocarbon group having 1 to 10 carbon atoms.

[0041] In formula (3), n is preferably an integer of 5 to 200, and m １ and m ２ are preferably each independently an integer of 3 to 200. １ ~R ３ Preferred examples of R in formula (1) and formula (2) are １ ~R ３ The preferred examples are the same as those of R. ４ are preferably each independently an alkylene group having 1 to 10 carbon atoms.

[0042] The first specific siloxane compound can be prepared by a known method, for example, by reacting a polysiloxane compound corresponding to the structural unit represented by formula (1) with a compound corresponding to the structural unit represented by formula (2) (for example, a cyclic ester compound such as ε-caprolactone or a polymer thereof).

[0043] When the first specific siloxane compound is produced by the above method, a first specific siloxane compound having a desired structure can be obtained by appropriately selecting the ratio of each compound.

[0044] The first specific siloxane compound is solid (powdered) at room temperature (25° C.), which has the advantage that a larger amount can be blended when preparing a solid encapsulating resin composition than when using a liquid siloxane compound.

[0045] From the viewpoint of suppressing warpage of the module, it is preferable that the elastomer component contains, as the siloxane compound, a compound having at least one selected from an epoxy group and an ether bond in a side chain (hereinafter also referred to as the "second specific siloxane compound").

[0046] The second specific siloxane compound is, for example, a compound represented by the formula (1) in which R １ and R ２ and a siloxane compound in which at least one of the groups represented by the formula (I) is selected from the group consisting of a monovalent organic group having an epoxy group and a polyalkylene ether group having 3 to 500 carbon atoms.

[0047] R １ and R ２ Examples of the monovalent organic group having an epoxy group represented by the formula (I) include an alkyl group having 1 to 10 carbon atoms and having an epoxy group. １ and R ２ Examples of polyalkylene ether groups having 3 to 500 carbon atoms represented by the formula (I) include monovalent groups having a structure in which multiple alkylene structures having 1 to 10 carbon atoms are linked by ether bonds. Specific examples of polyalkylene ether groups having 3 to 500 carbon atoms include monovalent groups containing an ethylene oxide structure (EO structure), a propylene oxide structure (PO structure), and combinations thereof. The second specific siloxane compound may have both a monovalent organic group having an epoxy group and a polyalkylene ether group having 3 to 500 carbon atoms in its side chain.

[0048] The elastomer component may contain both a first specific siloxane compound and a second specific siloxane compound. When the elastomer component contains both a first specific siloxane compound and a second specific siloxane compound, the content of the first specific siloxane compound relative to the total siloxane compounds is, for example, preferably 50% by mass or more, more preferably 50% to 90% by mass, and even more preferably 60% to 80% by mass. Furthermore, the total content of the first specific siloxane compound and the second specific siloxane compound relative to the total siloxane compounds is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more.

[0049] The encapsulating resin composition may contain, as the siloxane compound, another siloxane compound different from the first specific siloxane compound and the second specific siloxane compound.

[0050] The content of the elastomer component (preferably a siloxane compound) may be 0.1% by mass to 10.0% by mass, 0.5% by mass to 5.0% by mass, or 1.0% by mass to 3.0% by mass, relative to the total amount of the encapsulating resin composition.

[0051] The content of the elastomer component (preferably a siloxane compound) is preferably 1 to 30 parts by mass, and more preferably 2 to 20 parts by mass, per 100 parts by mass of the curable resin component (for example, 100 parts by mass of the total amount of the epoxy resin and the curing agent).

[0052] When the elastomer component contains at least one of an indene-styrene-coumarone copolymer and triphenylphosphine oxide, the amount thereof is, for example, preferably 1 to 30 parts by mass, and more preferably 2 to 20 parts by mass, per 100 parts by mass of the curable resin component (for example, 100 parts by mass of the total amount of the epoxy resin and the curing agent).

[0053] <Maleimide Compound> The maleimide compound is a compound having one or more maleimide groups. The maleimide compound has, for example, 1 to 20, 1 to 15, or 1 to 10 maleimide groups. The maleimide compounds may be used alone or in combination of two or more.

[0054] The maleimide compound may be liquid at 25° C. or solid at 25° C. The maleimide compound may be a monomer or polymer capable of radical polymerization.

[0055] In some embodiments, the maleimide compound includes a compound having two maleimide groups. In the present disclosure, a compound having two maleimide groups may be referred to as a "bismaleimide." In some embodiments, the maleimide compound includes a compound having three or more maleimide groups.

[0056] The maleimide group can be represented by the following formula: * indicates the bonding position to other atoms.

[0057]

[0058] In the formula, R １ and R ２ each independently represents a hydrogen atom, an alkyl group, or a halogen atom.

[0059] In some embodiments, the maleimide compound comprises a compound represented by formula (m):

[0060]

[0061] In formula (m), X ｍ represents an organic group, and M represents a maleimide group.

[0062] X ｍ The organic group represented by the formula (I) may be a group containing at least one carbon atom, for example, a group containing at least one selected from the group consisting of a saturated aliphatic hydrocarbon group, an unsaturated aliphatic hydrocarbon group, an aromatic hydrocarbon group, a saturated alicyclic hydrocarbon group, and an unsaturated alicyclic hydrocarbon group. The organic group may further contain a linking group containing a hetero atom, a substituent containing a hetero atom, or the like.

[0063] The maleimide compound preferably contains a compound represented by the following formula (m-1) or a compound represented by the following formula (m-2).

[0064]

[0065] In formula (m-1), R １ ~R ４ each independently represents a hydrogen atom, an alkyl group, or a halogen atom, and Y represents a hydrocarbon group. ５ R each independently represents an alkylene group, and n represents an integer of 0 or more. １ ~R ４ are each preferably independently a hydrogen atom. The hydrocarbon group represented by Y may have 5 or more carbon atoms, or may have 10 or more carbon atoms. The hydrocarbon group represented by Y may have 30 or less carbon atoms, or may have 20 or less carbon atoms.５ are each independently preferably an alkylene group having 1 to 5 carbon atoms, more preferably an alkylene group having 1 or 2 carbon atoms.

[0066] A maleimide compound may be synthesized. The method for synthesizing the maleimide compound is not particularly limited. For example, a synthesis method may be used in which a primary amine and maleic anhydride are used as raw materials to produce a maleamic acid or maleamic acid ester as a maleimide precursor, followed by ring closure by dehydration or dealcoholization. The alkyl group of the primary amine may be, for example, a group containing at least one selected from the group consisting of a saturated aliphatic hydrocarbon group, an unsaturated aliphatic hydrocarbon group, an aromatic hydrocarbon group, a saturated alicyclic hydrocarbon group, and an unsaturated alicyclic hydrocarbon group.

[0067] The content of the maleimide compound may be 0.5% by mass to 10.0% by mass, 1.0% by mass to 6.0% by mass, or 1.5% by mass to 5.0% by mass, relative to the total amount of the encapsulating resin composition.

[0068] <Curable Resin Component> The type of curable resin component contained in the encapsulating resin composition is not particularly limited. From the viewpoint of a balance of various properties as an encapsulant, a combination of an epoxy resin and a curing agent is preferred.

[0069] -Epoxy Resin- The type of epoxy resin is not particularly limited as long as it has an epoxy group in the molecule, and can be selected depending on the desired properties of the encapsulating resin composition. Specific examples of epoxy resins include novolac epoxy resins (phenol novolac epoxy resins, orthocresol novolac epoxy resins, etc.) obtained by epoxidizing novolac resins obtained by condensing or co-condensing, under an acid catalyst, at least one phenolic compound selected from the group consisting of phenolic compounds such as phenol, cresol, xylenol, resorcinol, catechol, bisphenol A, bisphenol F, etc., and naphthol compounds such as α-naphthol, β-naphthol, dihydroxynaphthalene, etc., with an aliphatic aldehyde compound such as formaldehyde, acetaldehyde, propionaldehyde, etc.; triphenylmethane epoxy resins obtained by epoxidizing triphenylmethane phenolic resins obtained by condensing or co-condensing, under an acid catalyst, the above-mentioned phenolic compound with an aromatic aldehyde compound such as benzaldehyde, salicylaldehyde, etc.; and novolac resins obtained by co-condensing, under an acid catalyst, the above-mentioned phenolic compound and naphthol compound with an aldehyde compound. diphenylmethane-type epoxy resins which are diglycidyl ethers of bisphenol A, bisphenol F, or the like; 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 phenolic compounds; sulfur-containing epoxy resins which are diglycidyl ethers of bisphenol S, or the like; 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 acids such as phthalic acid, isophthalic acid, and tetrahydrophthalic acid; glycidylamine-type epoxy resins in which active hydrogen bonded to nitrogen atoms of aniline, diaminodiphenylmethane, isocyanuric acid, or the like is substituted with a glycidyl group; dicyclopentadiene-type epoxy resins in which a co-condensation resin of dicyclopentadiene and a phenolic compound is epoxidized;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 are produced by epoxidizing an intramolecular olefin bond; paraxylylene-modified epoxy resins, which are glycidyl ethers of paraxylylene-modified phenolic resins; metaxylylene-modified epoxy resins, which are glycidyl ethers of metaxylylene-modified phenolic resins; terpene-modified epoxy resins, which are glycidyl ethers of terpene-modified phenolic resins; and dicyclopentadiene-modified phenolic resins, which are glycidyl ethers of dicyclopentadiene-modified phenolic resins. Examples of suitable epoxy resins include pentadiene-modified epoxy resins, 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 obtained by epoxidizing aralkyl-type phenolic resins such as phenol aralkyl resins and naphthol aralkyl resins. These epoxy resins may be used alone or in combination of two or more.

[0070] The epoxy equivalent (molecular weight / number of epoxy groups) of the epoxy resin is not particularly limited, but from the viewpoint of a balance of various properties such as moldability, reflow resistance, and electrical reliability, it is preferably 100 g / eq to 1000 g / eq, and more preferably 150 g / eq to 500 g / eq.

[0071] The epoxy equivalent of the epoxy resin may be a value measured by a method in accordance with JIS K 7236:2009, for example.

[0072] The softening point or melting point of the epoxy resin is not particularly limited, but is preferably 50°C to 130°C from the viewpoint of ease of handling during preparation of the encapsulating resin composition.

[0073] The melting point of the epoxy resin is a value measured by differential scanning calorimetry (DSC), and the softening point of the epoxy resin is a value measured by a method in accordance with JIS K 7234:1986 (ring and ball method).

[0074] From the viewpoints of strength, fluidity, heat resistance, moldability, and the like, the content of the epoxy resin is preferably 0.5% by mass to 30% by mass, more preferably 2% by mass to 20% by mass, and even more preferably 3.5% by mass to 13% by mass, relative to the total amount of the encapsulating resin composition.

[0075] -Curing Agent- The type of curing agent is not particularly limited and can be selected depending on the desired properties of the encapsulating resin composition. When the resin used in combination is an epoxy resin, examples of the curing agent include phenol curing agents, amine curing agents, acid anhydride curing agents, polymercaptan curing agents, polyaminoamide curing agents, isocyanate curing agents, and blocked isocyanate curing agents. From the viewpoint of heat resistance, it is preferable that the curing agent be one having a phenolic hydroxyl group in the molecule (phenol curing agent). These curing agents may be used alone or in combination of two or more.

[0076] Specific examples of the phenolic curing agent include polyhydric phenolic compounds such as resorcinol, catechol, bisphenol A, bisphenol F, and substituted or unsubstituted biphenols; novolak-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, and aminophenol, and naphthol compounds such as α-naphthol, β-naphthol, and dihydroxynaphthalene, with an aliphatic aldehyde compound such as formaldehyde, acetaldehyde, and propionaldehyde, under an acidic catalyst; and phenolic compounds synthesized from the above phenolic compounds and dimethoxyparaxylene, bis(methoxymethyl)biphenyl, etc. Examples of suitable phenolic curing agents include aralkyl-type phenolic resins such as aralkyl resins, naphthol aralkyl resins, and biphenyl aralkyl resins; phenolic resins modified with at least one of paraxylylene and metaxylylene; melamine-modified phenolic resins; terpene-modified phenolic resins; dicyclopentadiene-type phenolic resins and dicyclopentadiene-type naphthol resins synthesized by copolymerization of the above-mentioned phenolic compounds with 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-mentioned phenolic compounds with aromatic aldehyde compounds such as benzaldehyde and salicylaldehyde under an acidic catalyst; and phenolic resins obtained by copolymerization of two or more of these. These phenolic curing agents may be used alone or in combination of two or more.

[0077] The functional group equivalent of the curing agent (hydroxyl group equivalent in the case of a phenolic curing agent) is not particularly limited. From the viewpoint of the balance of 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.

[0078] The functional group equivalent of the curing agent (hydroxyl group equivalent in the case of a phenolic curing agent) may be a value measured by a method in accordance with JIS K 0070:1992, for example.

[0079] The softening point or melting point of the curing agent is not particularly limited. From the viewpoints of moldability and reflow resistance, it is preferably 40°C to 180°C, and from the viewpoint of handleability during production of the resin composition, it is more preferably 50°C to 130°C.

[0080] The melting point of the curing agent is a value measured by differential scanning calorimetry (DSC), and the softening point of the curing agent is a value measured by a method (ring and ball method) in accordance with JIS K 7234:1986.

[0081] The equivalent ratio of the resin to the curing agent, i.e., the ratio of the number of functional groups in the curing agent to the number of functional groups in the resin (number of functional groups in the curing agent / number of functional groups in the resin), is not particularly limited. In order to minimize the amount of unreacted components, it is preferably set in the range of 0.5 to 2.0, and more preferably in the range of 0.6 to 1.3. From the viewpoints of moldability and reflow resistance, it is even more preferably set in the range of 0.8 to 1.2.

[0082] When an active ester compound and a phenolic curing agent are used in combination as the curing agent, the molar ratio of the ester groups contained in the active ester compound to the phenolic hydroxyl groups contained in the phenolic curing agent (ester groups / phenolic hydroxyl groups) is preferably 9 / 1 to 1 / 9, more preferably 8 / 2 to 2 / 8, and even more preferably 3 / 7 to 7 / 3.

[0083] <Inorganic Filler> The type of inorganic filler is not particularly limited. Specific examples include inorganic materials such as silica (spherical silica, crystalline silica, etc.), glass, alumina, calcium carbonate, zirconium silicate, calcium silicate, silicon nitride, aluminum nitride, boron nitride, beryllia, zirconia, zircon, fosterite, steatite, spinel, mullite, titania, talc, clay, mica, and titanium compounds such as calcium titanate. Inorganic fillers having flame retardant properties may also be used. Examples of inorganic fillers having flame retardant properties include aluminum hydroxide, magnesium hydroxide, composite metal hydroxides such as magnesium-zinc composite hydroxide, and zinc borate.

[0084] Among the above inorganic fillers, silica is preferred from the viewpoint of reducing the linear expansion coefficient, 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. The inorganic filler may be in the form of powder, beads obtained by spheroidizing powder, fiber, etc.

[0085] The content of the inorganic filler contained in the encapsulating resin composition is not particularly limited. From the viewpoints of fluidity and strength, it is preferably more than 40% by volume, more preferably more than 50% by volume, even more preferably more than 50% by volume but not more than 90% by volume, and particularly preferably 55% to 85% by volume, based on the total volume of the encapsulating resin composition. Furthermore, from the viewpoints of fluidity and strength, the content of the inorganic filler contained in the encapsulating resin composition is preferably 75% to 92% by mass, more preferably 78% to 91% by mass, and even more preferably 80% to 90% by mass.

[0086] The content (vol %) of the inorganic filler in the encapsulating resin composition can be determined by the following method. A thin slice sample of the cured encapsulating resin composition is imaged using a scanning electron microscope (SEM). An arbitrary area S is identified in the SEM image, and the total area A of the inorganic fillers contained in area S is determined. The total area A of the inorganic fillers is divided by area S to convert it to a percentage (%), and this value is used as the content (vol %) of the inorganic filler in the encapsulating resin composition. Area S is set to an area sufficiently large relative to the size of the inorganic filler. For example, it is set to a size that contains 100 or more inorganic fillers. Area S may be the sum of multiple cross sections. The inorganic filler may have a bias in its presence in the direction of gravity when the encapsulating resin composition is cured. In this case, when imaging with an SEM, the entire cured product is imaged in the direction of gravity, and the area S containing the entire cured product in the direction of gravity is determined.

[0087] When the inorganic filler is particulate, its average particle diameter is not particularly limited. For example, the volume average particle diameter is preferably 0.2 μm to 40 μm, more preferably 0.2 μm to 20 μm, and even more preferably 0.5 μm to 15 μm. When the volume average particle diameter is 0.2 μm or more, an increase in the viscosity of the encapsulating resin composition tends to be further suppressed. When the volume average particle diameter is 40 μm or less, leakage of the encapsulating resin composition when filled into a mold tends to be suppressed. When the volume average particle diameter is 20 μm or less, the filling ability into narrow gaps tends to be further improved. The volume average particle diameter of the inorganic filler can be measured as the particle diameter (D50) at which the cumulative volume from the small diameter side reaches 50% in a volume-based particle size distribution obtained using a laser scattering diffraction particle size distribution analyzer.

[0088] The volume average particle diameter of the inorganic filler in the encapsulating resin composition or its cured product can be measured by a known method. For example, the inorganic filler is extracted from the encapsulating resin composition or the cured product using an organic solvent, nitric acid, aqua regia, or the like, and then thoroughly dispersed using an ultrasonic disperser or the like to prepare a dispersion. Using this dispersion, the volume average particle diameter of the inorganic filler can be measured from the volume-based particle size distribution measured using a laser diffraction scattering particle size distribution analyzer. Alternatively, the cured product can be embedded in a transparent epoxy resin or the like, polished, and the resulting cross-section observed using a scanning electron microscope to obtain a volume-based particle size distribution. Furthermore, the volume average particle diameter of the inorganic filler can also be measured by continuously observing two-dimensional cross-sections of the cured product using an FIB device (focused ion beam SEM) or the like, followed by three-dimensional structural analysis.

[0089] From the viewpoint of the fluidity of the encapsulating resin composition, the particle shape of the inorganic filler is preferably spherical rather than angular, and the particle size distribution of the inorganic filler is preferably wide.

[0090] <Various Additives> In addition to the components described above, the encapsulating resin composition may or may not independently contain various additives such as an organic filler, a curing accelerator, a coupling agent, an ion exchanger, a release agent, a flame retardant, a colorant, and a stress relaxation agent, as exemplified below. The encapsulating resin composition of the present disclosure may contain various additives known in the technical field as needed, in addition to the additives exemplified below.

[0091] -Curing Accelerator- The encapsulating resin composition may contain a curing accelerator. The type of curing accelerator is not particularly limited and can be selected depending on the type of curable resin component, the desired properties of the encapsulating resin composition, and the like. Examples of the curing accelerator 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; 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 a compound having a π bond, such as 2-isophenylmethane; cyclic amidinium compounds such as the tetraphenylborate salt of DBU, the tetraphenylborate salt of DBN, the tetraphenylborate salt of 2-ethyl-4-methylimidazole, and the 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, 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, trialkylphosphine, dialkyla tertiary phosphines such as alkyldiarylphosphines and alkyldiarylphosphines; phosphine compounds such as complexes of the above tertiary phosphines with organoborons; quinone compounds such as the above tertiary phosphines or the above phosphine compounds with 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, and diazophenylmethane. or a compound having intramolecular polarization obtained by adding a compound having a π bond to the tertiary phosphine or the phosphine compound; a compound obtained by adding the above-mentioned tertiary phosphine or the above-mentioned phosphine compound to 4-bromophenol, 3-bromophenol, 2-bromophenol, 4-chlorophenol, 3-chlorophenol, 2-chlorophenol, 4-iodophenol, 3-iodophenol, 2-iodophenol, 4-bromo-2-methylphenol, 4-bromo-3-methylphenol, 4-bromo-2,6-dimethylphenol, 4-bromo-3,5-dimethylphenol, 4-bromo-2,6-di-t-butylphenol, Examples of the curing accelerator include compounds having intramolecular polarization obtained by reacting a halogenated phenol compound such as 1-bromo-2-naphthol, 4-chloro-1-naphthol, 1-bromo-2-naphthol, 6-bromo-2-naphthol, or 4-bromo-4'-hydroxybiphenyl, followed by a dehydrohalogenation step; tetra-substituted phosphonium compounds such as tetraphenylphosphonium; tetra-substituted phosphonium compounds and tetra-substituted borates having no phenyl group bonded to the boron atom, such as tetra-p-tolylborate; and salts of tetraphenylphosphonium compounds with phenol compounds. One type of curing accelerator may be used alone, or two or more types may be used in combination.

[0092] When the encapsulating resin composition contains a curing accelerator, the amount thereof is preferably 0.1 to 8 parts by mass, more preferably 0.3 to 7 parts by mass, and even more preferably 0.5 to 6 parts by mass, per 100 parts by mass of the curable resin component (e.g., 100 parts by mass of the total amount of epoxy resin and curing agent). By setting the content of the curing accelerator within the above range, the curing rate of the molding resin composition of the present disclosure becomes an appropriate value, making it easy to produce molded articles.

[0093] -Coupling Agent- The encapsulating resin composition may contain a coupling agent. From the viewpoint of improving the adhesion between the epoxy resin and the curing agent and the inorganic filler, the encapsulating resin composition preferably contains a coupling agent. Examples of the coupling agent include silane compounds such as epoxysilane, mercaptosilane, aminosilane, alkylsilane, ureidosilane, vinylsilane, and disilazane, titanium compounds, aluminum chelate compounds, and aluminum / zirconium compounds. One type of coupling agent may be used alone, or two or more types may be used in combination. The molecular weight of the coupling agent may be, for example, 1,000 or less, preferably 100 to 800, and more preferably 100 to 500.

[0094] Among these, the coupling agent is preferably a silane compound from the viewpoint of ease of handling. Examples of the silane compound include epoxy group-containing silane compounds such as 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, and 3-anilinopropyltrimethoxysilane; vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris(β-methoxyethoxy)silane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyldimethylmethoxysilane, and 3-methacryloxypropyldimethylethoxysilane. silane compounds having an unsaturated bond such as thoxysilane, 3-acryloxypropyltrimethoxysilane, 3-acryloxypropyltriethoxysilane, and vinyltriacetoxysilane; sulfur atom-containing silane compounds such as γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, and bis(triethoxysilylpropyl)tetrasulfide; amino group-containing silane compounds such as γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-[bis(β-hydroxyethyl)]aminopropyltriethoxysilane, N-β-(aminoethyl)-γ-aminopropyltriethoxysilane, and N-(trimethoxysilylpropyl)ethylenediamine; isocyanate group-containing silane compounds such as isocyanatepropyltrimethoxysilane and isocyanatepropyltriethoxysilane;Methyltrimethoxysilane, methyltriethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, diphenylsilanediol, triphenylmethoxysilane, triphenylethoxysilane, triphenylsilanol, cyclohexyltrimethoxysilane, cyclohexyltriethoxysilane, cyclohexylmethyldimethoxysilane, N-β-(N-vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane, hexamethyldisilane, 2-triethoxysilyl-N-(1,3-dimethylbutylidene)propylamine, 3-triethoxysilyl-N-( Silane compounds such as 1,3-dimethyl-butylidene)propylamine, N-(3-triethoxysilylpropyl)phenylimine, 3-(3-(triethoxysilyl)propylamino)-N,N-dimethylpropionamide, N-triethoxysilylpropyl-β-alanine methyl ester, 3-(triethoxysilylpropyl)dihydro-3,5-furandione, and bis(trimethoxysilyl)benzene; and imidazole silane compounds which are reaction products of imidazole compounds such as 1H-imidazole, 2-alkylimidazole, 2,4-dialkylimidazole, and 4-vinylimidazole with γ-glycidoxypropylalkoxysilanes such as γ-glycidoxypropyltrimethoxysilane and γ-glycidoxypropyltriethoxysilane. These compounds may be used alone or in combination of two or more.

[0095] When the encapsulating resin composition contains a coupling agent, the content of the coupling agent is preferably 0.05 parts by mass to 5 parts by mass, and more preferably 0.1 parts by mass to 2.5 parts by mass, relative to 100 parts by mass of the inorganic filler. When the amount of the coupling agent is 0.05 parts by mass or more relative to 100 parts by mass of the inorganic filler, the adhesiveness tends to be further improved. When the amount of the coupling agent is 5 parts by mass or less relative to 100 parts by mass of the inorganic filler, the moldability of the module tends to be further improved.

[0096] -Mold Release Agent- The encapsulating resin composition may contain a mold release agent from the viewpoint of obtaining good releasability from the mold during molding. There are no particular limitations on the mold release agent, and conventionally known ones can be used. Specific 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. One type of mold release agent may be used alone, or two or more types may be used in combination.

[0097] When the encapsulating resin composition contains a release agent, the amount thereof is preferably 0.01 to 10 parts by mass, more preferably 0.1 to 5 parts by mass, per 100 parts by mass of the curable resin component (e.g., 100 parts by mass of the total amount of the epoxy resin and the curing agent). When the amount of the release agent is 0.01 parts by mass or more per 100 parts by mass of the curable resin component, sufficient release properties tend to be obtained. When the amount of the release agent is 10 parts by mass or less per 100 parts by mass of the curable resin component, better adhesion tends to be obtained.

[0098] Flame Retardant The encapsulating resin composition may further contain a flame retardant. There are no particular limitations on the flame retardant, and conventionally known flame retardants can be used. Specific examples include organic or inorganic compounds containing a halogen atom, an antimony atom, a nitrogen atom, or a phosphorus atom, and metal hydroxides. One type of flame retardant may be used alone, or two or more types may be used in combination.

[0099] When the encapsulating resin composition contains a flame retardant, the amount thereof is not particularly limited as long as it is an amount sufficient to obtain the desired flame retardant effect. For example, the amount of the flame retardant is preferably 1 to 30 parts by mass, and more preferably 2 to 20 parts by mass, per 100 parts by mass of the curable resin component (e.g., 100 parts by mass of the epoxy resin and the curing agent combined).

[0100] Colorant The encapsulating resin composition may further contain a colorant. Examples of the colorant include known colorants such as carbon black, organic dyes, organic pigments, titanium oxide, red lead, and red iron oxide. The content of the colorant can be appropriately selected depending on the purpose, etc. One type of colorant may be used alone, or two or more types may be used in combination.

[0101] When the encapsulating resin composition contains a colorant, the amount of the colorant is preferably 0.01 to 10 parts by mass, and more preferably 0.1 to 5 parts by mass, relative to 100 parts by mass of the curable resin component (for example, 100 parts by mass of the total amount of the epoxy resin and the curing agent).

[0102] <Physical Properties> The encapsulating resin composition of the present disclosure preferably has a mold shrinkage of 0.30% or less, more preferably 0.25% or less, and even more preferably 0.20% or less when cured. A lower mold shrinkage is preferable, and there is no particular restriction on the lower limit, and it may be, for example, 0% or less. The mold shrinkage of a cured product is measured as follows. The encapsulating resin composition is molded using a transfer molding machine under conditions of a molding temperature of 175°C, a molding pressure of 6.9 MPa, and a curing time of 120 seconds to obtain a plate-shaped molded product (length 127 mm, width 12.7 mm, thickness 6.4 mm). The molded product is post-cured at 175°C for 5 hours to obtain a plate-shaped cured product. The mold shrinkage (%) is calculated using the previously measured length D of the mold cavity at 25°C and the length d of the cured product at room temperature (25°C) according to the following formula: Mold shrinkage (%) = ((D - d) / D) × 100

[0103] The encapsulating resin composition of the present disclosure preferably has a flexural strength of 115 MPa or more, more preferably 122 MPa or more, and even more preferably 145 MPa or more when cured. Furthermore, the flexural strength of the cured product is preferably 200 MPa or less, more preferably 190 MPa or less, and even more preferably 180 MPa or less. The flexural strength of the cured product is measured as follows. The encapsulating resin composition is molded using a transfer molding machine under conditions of a molding temperature of 175°C, a molding pressure of 6.9 MPa, and a curing time of 120 seconds, and the molded product is post-cured at 175°C for 5 hours to obtain a plate-shaped cured product. The flexural strength (MPa) of a 10 mm x 50 mm x 3 mm cured product measured at 25°C using a Tensilon universal testing machine (e.g., A&D Corporation's "Tensilon RTG-1310") is defined as the room temperature flexural strength.

[0104] The encapsulating resin composition of the present disclosure preferably has a modulus of elasticity of 6 GPa or more, more preferably 8 GPa or more, and even more preferably 12 GPa or more when cured. Furthermore, the modulus of elasticity of the cured product is preferably 30 GPa or less, more preferably 19 GPa or less, and even more preferably 16 GPa or less. The method for measuring the modulus of elasticity of the cured product is as follows. The encapsulating resin composition is molded using a transfer molding machine under conditions of a molding temperature of 175°C, a molding pressure of 6.9 MPa, and a curing time of 120 seconds, and the molded product is post-cured at 175°C for 5 hours to obtain a plate-shaped cured product. The modulus of elasticity (GPa) of a cured product measuring 10 mm x 50 mm x 3 mm measured at 25°C using a Tensilon universal testing machine (e.g., A&D Corporation's "Tensilon RTG-1310") is taken as the room temperature modulus.

[0105] The encapsulating resin composition of the present disclosure, when cured, preferably has a product of flexural strength (MPa) and molding shrinkage (%) (flexural strength MPa × molding shrinkage %) of 24 to 38, more preferably 25 to 36, and even more preferably 26 to 34.

[0106] The encapsulating resin composition of the present disclosure, when cured, preferably has a product of the elastic modulus (GPa) and molding shrinkage (%) (elastic modulus GPa × molding shrinkage %) of 3.5 to 6.8, more preferably 3.7 to 6.5, and even more preferably 4.0 to 6.0.

[0107] <Method for Preparing Encapsulating Resin Composition> The method for preparing the encapsulating resin composition is not particularly limited, and any method may be used as long as it can sufficiently disperse and mix the various components. A common method includes thoroughly mixing predetermined amounts of components using a mixer or the like, melt-kneading the mixture using a mixing roll, extruder, or the like, cooling, and pulverizing the mixture. More specifically, for example, a method includes stirring and mixing predetermined amounts of the above-mentioned components, kneading the mixture using a kneader, roll, extruder, or the like that has been preheated to 70°C to 140°C, cooling, and pulverizing the mixture.

[0108] [Semiconductor Module] A semiconductor module according to the present disclosure includes a circuit board, a semiconductor element provided on one surface of the circuit board, a first bonding layer bonding the semiconductor element to the circuit board, a cooler provided on a surface of the circuit board opposite to the surface on which the semiconductor element is provided, a second bonding layer bonding the circuit board to the cooler, and an encapsulant covering the semiconductor element, the first bonding layer, and the circuit board, wherein the encapsulant includes a cured product of the encapsulating resin composition according to the present disclosure.

[0109] In a semiconductor module including a circuit board, which is bonded to a semiconductor element via a first bonding layer, and a cooler, which is bonded to the circuit board via a second bonding layer, the encapsulating resin composition of the present disclosure is used as an encapsulant that covers the semiconductor element, the bonding layer, and the circuit board. By forming the encapsulant using the encapsulating resin composition, it is possible to reduce stress applied to the entire module during heating or cooling, and to suppress peeling of the second bonding layer.

[0110] <Example of Semiconductor Module> A power module 10, which is an example of a semiconductor module according to the present disclosure, will be described below. FIG. 1 is a cross-sectional view schematically illustrating the power module 10. For ease of explanation, the following description may be given assuming that the positional relationships (upper and lower relationships, etc.) of the components of the power module 10 are as shown in the drawings. However, the positional relationships in this description are unrelated to the positional relationships during use, manufacturing, etc. of the power module 10. The positional relationships and relative sizes of the components of the power module 10 are not limited to those shown in the drawings.

[0111] The power module 10 includes a power semiconductor chip 1, a first bonding layer 2, a metal circuit board 3, a second bonding layer 4, a metal cooler 5, a sealing material 6, and a lead frame 7. The first bonding layer 2 bonds the power semiconductor chip 1 and the metal circuit board 3 together, and may be, for example, a sintered layer formed by sintering a sintering paste containing metal particles.

[0112] Examples of the sintering paste include an Ag sintering paste containing silver particles, an Al sintering paste containing aluminum particles, and a Cu sintering paste containing copper particles.

[0113] The power semiconductor chip 1 is, for example, an insulated gate bipolar transistor (IGBT), a diode, etc. An electrode pattern (not shown) is formed on the upper surface of the power semiconductor chip 1, and a conductive pattern (not shown) is formed on the lower surface of the power semiconductor chip 1. The lower surface of the power semiconductor chip 1 is bonded to one surface of a metal circuit board 3 via a first bonding layer 2. The electrode pattern on the upper surface of the power semiconductor chip 1 is electrically connected to a wire, a lead frame, etc.

[0114] The power semiconductor chip 1 is made of, for example, SiC, GaN, Ga ２ O ３ Or it is a semiconductor made of diamond.

[0115] The metal circuit board 3 may be a circuit board having a Cu circuit. For example, a Cu circuit is provided on the surface of the power semiconductor chip 1 and the lead frame 7, and a Si ３ N ４ The substrate may be a substrate in which a ceramic substrate layer such as a Cu layer is laminated in the thickness direction.

[0116] The power semiconductor chip 1, the first bonding layer 2, and the metal circuit board 3 are encapsulated with an encapsulant 6 formed by molding the encapsulating resin composition of the present disclosure. At this time, a lead frame 7 electrically connected to the Cu circuit may also be encapsulated with the encapsulant 6. Methods for encapsulating each component using the encapsulating resin composition include compression molding, transfer molding, injection molding, and the like, and any of these can be employed.

[0117] In the power module 10, the metal circuit board 3 and the metal cooler 5 are bonded via a second bonding layer 4. The metal cooler 5 is provided on the side of the metal circuit board 3 opposite to the side on which the power semiconductor chip 1 is provided. The second bonding layer 4 and the metal cooler 5 may be partially sealed with a sealing material 6 formed by molding the sealing resin composition of the present disclosure, or may not be sealed at all.

[0118] The second bonding layer 4 may be, for example, a sintered layer obtained by sintering a sintering paste containing metal particles, similar to the first bonding layer 2 .

[0119] The metal cooler 5 is a type of heat dissipation member and has a plate-shaped base 5A and a plurality of fins 5B extending from the underside of the base 5A. Examples of materials for the metal cooler 5 include copper and aluminum. The configuration, material, etc. of the cooler are not particularly limited as long as it is capable of dissipating heat generated in the power module 10, such as heat generated in the power semiconductor chip 1.

[0120] The above-described embodiment will be specifically described below using examples, but the scope of the above-described embodiment is not limited to these examples.

[0121] [Preparation of Encapsulating Resin Composition] The components shown in Table 1 were mixed in the amounts (parts by mass) shown in Table 1 to prepare an encapsulating resin composition. Specifically, the materials were mixed, then kneaded in a twin-screw extruder with the internal temperature adjusted to 70°C to 100°C, cooled, and pulverized to obtain an encapsulating resin composition. Details of each component are as follows.

[0122] Epoxy resin: triphenylmethane type epoxy resin, epoxy equivalent: 165 g / eq to 176 g / eq; Curing agent 1: phenol-formaldehyde resin, hydroxyl equivalent: 106 g / eq; Curing agent 2: biphenylaralkyl type phenol resin, hydroxyl equivalent: 202 g / eq; Curing accelerator: 2-phenyl-4-methylimidazole; Coupling agent: N-phenyl-3-aminopropyltrimethoxysilane; Mold release agent: carnauba wax; Pigment: carbon black; Maleimide compound: compound (R) represented by the above formula (m-2). ５ is a methylene group) Siloxane compound: a compound having a structure represented by the above formula (3) (R １ and R ２ are each independently a hydrogen atom, R ３ is a pentamethylene group, R ４ is a compound with an alkylene group having 1 to 10 carbon atoms) Inorganic filler: fused silica with an average particle size of 31.5 μm

[0123] (Preparation of Evaluation Sample) Metal circuit board (Cu circuit, Si３ N ４ The encapsulating resin composition was molded at 175°C for 120 seconds to encapsulate a substrate (900 μm thick) containing a Cu layer and a Cu layer, and then post-cured for 5 hours to produce a cured product (5.4 mm thick). Then, using a sintering paste containing Ag as metal particles, the metal circuit board and a metal cooler made of Cu were sinter-bonded on the side of the metal circuit board opposite the cured product side under conditions of 250°C, 13 MPa, and 10 minutes. The sinter-bonded bonding layer (150 μm thick) was left to cool at 25°C, and then the peeling rate (percentage of peeled area) was calculated. The sintering resistance was evaluated as follows. The results are shown in Table 1. A: Peeling rate 0% to 2% B: Peeling rate more than 2% but not more than 10% C: Peeling rate more than 10% but not more than 20% D: Peeling rate more than 20%

[0124] (Molding Shrinkage Measurement) The encapsulating resin composition was molded using a transfer molding machine under conditions of a molding temperature of 175°C, a molding pressure of 6.9 MPa, and a curing time of 120 seconds to obtain a plate-shaped molded product (length 127 mm, width 12.7 mm, thickness 6.4 mm). The molded product was post-cured for 5 hours at 175°C to obtain a plate-shaped cured product. The molding shrinkage (%) was calculated using the following formula from the previously measured length D of the mold cavity at 25°C and the length d of the cured product at room temperature (25°C). The results are shown in Table 1. Molding shrinkage (%) = ((D - d) / D) × 100

[0125] (Evaluation of flexural strength) The encapsulating resin composition was molded using a transfer molding machine under conditions of a molding temperature of 175°C, a molding pressure of 6.9 MPa, and a curing time of 120 seconds, and the molded product was post-cured at 175°C for 5 hours to obtain a plate-shaped cured product. A 10 mm x 50 mm x 3 mm-sized cured product was measured using A&D's "Tensilon RTG-1310." The flexural strength (MPa) measured at 25°C is shown in Table 1 as the room temperature flexural strength.

[0126] (Evaluation of Elastic Modulus) The encapsulating resin composition was molded using a transfer molding machine under conditions of a molding temperature of 175°C, a molding pressure of 6.9 MPa, and a curing time of 120 seconds, and the molded product was post-cured at 175°C for 5 hours to obtain a plate-shaped cured product. A 10 mm x 50 mm x 3 mm-sized cured product was measured using A&D Corporation's "Tensilon RTG-1310." The elastic modulus (GPa) measured at 25°C is shown in Table 1 as the room temperature elastic modulus. In Table 1, "flexural strength x molding shrinkage" is the value of "flexural strength MPa x molding shrinkage", and "elastic modulus x molding shrinkage" is the value of "elastic modulus GPa x molding shrinkage".

[0127]

[0128] As shown in Table 1, in each example, it was possible to reduce the molding shrinkage rate, thereby reducing the stress applied to the entire module and producing an encapsulant capable of suppressing peeling of the bonding layer. In particular, it was possible to reduce the stress applied to the entire module and produce an encapsulant capable of suppressing peeling of the bonding layer by adjusting the bending strength or elastic modulus while taking the molding shrinkage rate into consideration.

[0129] The disclosure of Japanese Patent Application No. 2024-146905 is incorporated herein by reference in its entirety. All documents, patent applications, and technical standards mentioned herein are incorporated herein by reference to the same extent as if each individual document, patent application, and technical standard was specifically and individually indicated to be incorporated by reference.

Claims

1. An encapsulating resin composition containing a curable resin component, an inorganic filler, an elastomer component, and a maleimide compound.

2. The encapsulating resin composition according to claim 1, wherein the elastomer component is in a liquid, solid or particulate form and contains a compound having a siloxane bond.

3. The encapsulating resin composition according to claim 2, wherein the compound having a siloxane bond includes a compound having a structural unit represented by the following formula (1): [In formula (1), R １ and R ２ are each independently selected from the group consisting of an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a monovalent organic group having an epoxy group, a monovalent organic group having a carboxy group, and a polyalkylene ether group having 3 to 500 carbon atoms.

4. The encapsulating resin composition according to claim 2, wherein the compound having a siloxane bond includes a compound having at least one selected from an epoxy group and an ether bond in a side chain.

5. The encapsulating resin composition according to claim 1, wherein the curable resin component comprises an epoxy resin and a curing agent.

6. The encapsulating resin composition according to claim 5, wherein the curing agent comprises a phenolic curing agent.

7. The encapsulating resin composition according to any one of claims 1 to 6, which is used as an encapsulating material for electronic component devices.

8. A semiconductor module comprising: a circuit board; a semiconductor element provided on one surface of the circuit board; a first bonding layer bonding the semiconductor element to the circuit board; a cooler provided on the surface of the circuit board opposite to the surface on which the semiconductor element is provided; a second bonding layer bonding the circuit board to the cooler; and an encapsulant covering the semiconductor element, the first bonding layer, and the circuit board, wherein the encapsulant comprises a cured product of the encapsulating resin composition according to any one of claims 1 to 6.

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