Epoxy resin composition for semiconductor encapsulation and semiconductor device obtained using same

Abstract

This epoxy resin composition for semiconductor encapsulation is characterized by comprising components (A) to (D): (A) an epoxy resin represented by general formula (1); (B) a phenolic hardener; (C) an inorganic filler; (D) organosilicon compounds comprising (D1) and (D2), (D1) being one or more epoxidized organosilicon compounds selected from among organooxysilanes represented by general formula (2) and hydrolyzates thereof and (D2) being an organosilicon compound which has an S-Si bond and is an organooxysilane represented by general formula (3). Due to this, the resin composition for semiconductor encapsulation gives cured objects which have satisfactory electrical insulating properties at high temperatures, have high adhesiveness to copper, silver, organic primers, etc., and are less apt to detach after reflow soldering. Also provided is a semiconductor device obtained through encapsulation with a cured object of the resin composition for semiconductor encapsulation.

Description

Epoxy resin composition for semiconductor encapsulation and semiconductor device using the same

[0001] The present invention relates to a semiconductor encapsulation epoxy resin composition used for encapsulating semiconductor devices, and to a semiconductor device encapsulated using the semiconductor encapsulation epoxy resin composition.

[0002] In recent years, power semiconductor devices incorporating elements using Si (silicon), SiC (silicon carbide), and GaN (gallium nitride) have attracted attention (Patent Document 1). Power semiconductors are semiconductors that can handle large voltages and currents, and are attracting attention from an energy-saving perspective because they have low energy loss. Elements that can operate under harsh conditions, such as elements using SiC and GaN (semiconductor elements), require semiconductor encapsulants provided in semiconductor devices to protect these elements to have higher heat resistance than before. Generally, the glass transition temperature (Tg) is used as an indicator to represent the heat resistance of the cured product of a semiconductor encapsulation resin composition. This is because, in the temperature range above Tg, the encapsulation resin composition (cured product) becomes rubbery, and as a result, its electrical insulation, strength, and adhesive strength decrease (Patent Documents 2 and 3).

[0003] Power semiconductor devices are sometimes joined to printed circuit boards (PCBs) using surface mount technology. This technique involves applying lead-free solder paste to the PCB, precisely placing the semiconductor device, and then passing it through a reflow oven for soldering. However, the vaporization of moisture contained in the semiconductor device generates very high stress inside the device. As a result, the semiconductor element or lead frame may delaminate from the sealing resin, or the sealing resin may crack.

[0004] To improve solder reflowability, epoxy resin compositions containing biphenyl-type epoxy resins, which are low-viscosity epoxy resins filled with a high concentration of inorganic fillers, have been proposed (Patent Documents 4 and 5). However, when these biphenyl-type epoxy resins are used, the Tg is low, and electrical insulation at high temperatures decreases. Numerous techniques have also been proposed to improve adhesion to semiconductor elements and lead frames. From the viewpoint of improving adhesion to metal surfaces, compounds containing sulfur atoms have attracted attention for a long time, and in recent years, compounds having disulfide groups bonded to aromatic hydrocarbon groups such as diphenyl disulfide have been proposed (Patent Documents 6 and 7). However, a resin composition that has high adhesion to copper and silver, and exhibits little peeling after solder reflow, has yet to be realized.

[0005] JP 2005-167035 JP 2018-165296 JP 2022-98698 JP 5-131486 JP 8-253555 JP 10-176036 JP 2005-002221

[0006] Conventional technologies have a problem in that it is difficult to realize a cured product of a semiconductor encapsulation resin composition that has high adhesion to copper, silver, etc., and exhibits little peeling after solder reflow.

[0007] The present invention has been made to solve the above problems, and aims to provide a semiconductor encapsulation resin composition that provides a cured product with good electrical insulation at high temperatures, high adhesion to copper, silver, organic primers, etc., and less peeling after solder reflow, and a semiconductor device encapsulated with a cured product of the semiconductor encapsulation resin composition.

[0008] To solve the above problems, the present invention provides an epoxy resin composition for semiconductor encapsulation, characterized in that it contains the following components (A) to (D). (A) An epoxy resin represented by the following general formula (1) (In the formula, R １ R is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. ２(1) represents a hydrogen atom or a methyl group. n is an integer from 0 to 10. ) (B) Phenolic curing agent (C) Inorganic filler (D) Organosilicon compounds containing the following (D1) and (D2) (D1) Epoxy group-containing organosilicon compounds which are one or more selected from organoxysilanes represented by the following general formula (2) and their hydrolysates, (In the formula, R ３ R is an alkyl group having 1 to 4 carbon atoms independently. ４ (D2) An organoxysilane represented by the following general formula (3), which is an organosilicon compound having an S-Si bond. (In the formula, R ３ , R ４ n and m are the same as in equation (2) above, and R ５ (These are independently C1-C10 alkyl groups, C6-C10 aryl groups, or C1-C20 alkoxy groups.)

[0009] Such an epoxy resin composition for semiconductor encapsulation provides good electrical insulation at high temperatures, high adhesion to copper, silver, organic primers, etc., and yields a cured product with minimal peeling after solder reflow.

[0010] Furthermore, it is preferable that the (D1) component is a hydrolyzed product of the general formula (2).

[0011] Such a (D1) component is preferable because it can improve adhesion with the semiconductor element and lead frame.

[0012] Furthermore, the present invention provides a semiconductor device sealed with a cured product of the aforementioned epoxy resin composition for semiconductor encapsulation.

[0013] The cured product of the aforementioned epoxy resin composition for semiconductor encapsulation is effective as an encapsulation resin for semiconductor devices.

[0014] Furthermore, it is preferable that the semiconductor device is a power semiconductor device.

[0015] The semiconductor device can be suitably used for a power semiconductor device.

[0016] Further, it is preferable that the semiconductor device is a surface-mounted semiconductor device.

[0017] The semiconductor device can be suitably used for a surface-mounted semiconductor device.

[0018] As described above, the epoxy resin composition for semiconductor encapsulation of the present invention has excellent electrical insulation at high temperatures, excellent adhesion to copper lead frames, silver-plated lead frames, and organic primers, and also excellent reflow resistance characteristics. Therefore, it is suitable for encapsulating a surface-mounted semiconductor device using a cured product of the epoxy resin composition for semiconductor encapsulation of the present invention, particularly for encapsulating a power semiconductor device.

[0019] As described above, there has been a demand for the development of a resin composition for semiconductor encapsulation that has good electrical insulation at high temperatures, high adhesion to copper, silver, organic primers, etc., and gives a cured product with little peeling after solder reflow, and a semiconductor device encapsulated with the cured product.

[0020] As a result of intensive studies on the above problems, the present inventors have found that the problems of the present invention can be solved by an epoxy resin composition for semiconductor encapsulation containing the following components (A) to (D), and have completed the present invention.

[0021] That is, the present invention is an epoxy resin composition for semiconductor encapsulation, characterized by containing the following components (A) to (D). (A) An epoxy resin represented by the following general formula (1) (In the formula, R １ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R ２ represents a hydrogen atom or a methyl group. n is an integer of 0 to 10.) (B) A phenolic curing agent (C) An inorganic filler (D) An organosilicon compound containing the following (D1) and (D2) (D1) An epoxy group-containing organosilicon compound selected from one or more of organoxysilanes represented by the following general formula (2) and their hydrolyzates, (In the formula, R ３R is an alkyl group having 1 to 4 carbon atoms independently. ４ (D2) An organoxysilane represented by the following general formula (3), which is an organosilicon compound having an S-Si bond. (In the formula, R ３ , R ４ n and m are the same as in equation (2) above, and R ５ (These are independently C1-C10 alkyl groups, C6-C10 aryl groups, or C1-C20 alkoxy groups.)

[0022] The present invention will be described in detail below, but the present invention is not limited to these descriptions.

[0023] [(A) Epoxy resin] In the present invention, (A) epoxy resin is an epoxy resin containing a triphenolalkane type structure represented by the following general formula (1). (In the formula, R １ R is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. ２ (where n is an integer between 0 and 10, the first character represents a hydrogen atom or a methyl group.)

[0024] The structure of the general formula (1) above has a high concentration of epoxy functional groups and a high crosslinking density in the cured product, which raises the glass transition temperature (Tg), resulting in improved electrical insulation properties at high temperatures, resin strength, and adhesion to semiconductor devices and lead frames. The highest Tg occurs at R １ This is an unsubstituted structure where the atom is a hydrogen atom. １ In the case of a C3 isopropyl group and a C4 tert-butyl group, the bulky substituents conceal the hydroxyl group produced by the ring-opening reaction of the epoxy resin. This results in good electrical insulation properties at high temperatures and reduced moisture absorption.

[0025] In this invention, in addition to the epoxy resin represented by the general formula (1) above, various epoxy resins commonly used for semiconductor encapsulation can be used in combination. By using them in combination, it is possible to improve moisture resistance and reflow resistance while maintaining a high Tg.

[0026] The proportion of epoxy resin represented by the above general formula (1) is preferably 5% by mass or more and 100% by mass or less of the epoxy resin. If it is 5% by mass or more, the Tg is high and there are no problems with electrical insulation properties at high temperatures. Preferably it is 6% by mass or more and 90% by mass or less, and more preferably 7% by mass or more and 80% by mass or less.

[0027] Examples of epoxy resins represented by the above general formula (1) include novolac-type epoxy resins, cresol-novolac-type epoxy resins, aralkyl-type epoxy resins, biphenyl skeleton-containing aralkyl-type epoxy resins, biphenyl-type epoxy resins, dicyclopentadiene-type epoxy resins, polyfunctional epoxy resins, heterocyclic epoxy resins, naphthalene ring-containing epoxy resins, bisphenol A-type epoxy compounds, bisphenol F-type epoxy compounds, stilbene-type epoxy resins, triglycidyl isocyanate compounds, monoallyl diglycidyl isocyanate compounds, and copolymer compounds obtained by hydrosilylation reactions of alkenyl group-containing epoxy compounds with hydrogen organopolysiloxanes represented by the following average composition formula (4).

[0028]

[0029] In the above average composition formula (4), R is a monovalent hydrocarbon group having 1 to 10 carbon atoms, preferably 1 to 6 carbon atoms, where a is 0.01 ≤ a ≤ 1, and b is 1 ≤ b ≤ 3, or 1.01 ≤ a + b < 4.

[0030] These can be used individually or in combination of two or more types.

[0031] Alkenyl group-containing epoxy compounds can be obtained, for example, by epoxidizing an alkenyl group-containing phenol resin with epichlorohydrin, or by partially reacting a conventionally known epoxy compound with 2-allylphenol. The epoxy compound can be represented, for example, by the following general formula (5).

[0032] (R ２’ R is an aliphatic monovalent hydrocarbon group having an alkenyl group, with 3 to 15 carbon atoms, preferably 3 to 5 carbon atoms, and ３’ This is a glycidyloxy group or -OCH ２ CH(OH)CH ２ The group is represented by OR', where R' is a monovalent hydrocarbon group having an alkenyl group and having 3 to 10 carbon atoms, preferably 3 to 5 carbon atoms, and k is 1. ’ (where x is 0 or 1, x is a positive number between 1 and 30, and y is a positive number between 1 and 3.)

[0033] Examples of epoxy compounds represented by the above general formula (5) include the following compounds. (In the equation, x and y are positive numbers such that 1 < x < 10 and 1 < y < 3.)

[0034] The hydrogen organopolysiloxane represented by the above average composition formula (4) has one or more hydrosilyl groups in one molecule. In the above average composition formula (4), R can be an alkyl group such as a methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, pentyl group, neopentyl group, hexyl group, octyl group, nonyl group, decyl group, etc., an alkenyl group such as a vinyl group, allyl group, propenyl group, isopropenyl group, butenyl group, hexenyl group, cyclohexenyl group, octenyl group, etc., an aryl group such as a phenyl group, tolyl group, xylyl group, naphthyl group, etc., a alkyl group such as a benzyl group, phenylethyl group, phenylpropyl group, etc. Preferably, it is a methyl group, an ethyl group, or a phenyl group.

[0035] The hydrogen organopolysiloxane represented by the average composition formula (4) above may be linear, cyclic, or branched. For example, it can be represented by the following general formulas (a) to (c).

[0036] In the above general formula (a), R is independently a monovalent hydrocarbon group having 1 to 10 carbon atoms, preferably 1 to 6 carbon atoms, and R ９ R is a group selected from a hydrogen atom and the above-mentioned R options,８ The formula is as shown below. n １ n is an integer between 5 and 200. ２ n is an integer between 0 and 2, and n ３ n is an integer between 0 and 10. ４ It is either 1 or 0.

[0037] The above R ８ In the formula showing R and R ９ As stated above, n ５ n is an integer between 1 and 10. However, the compound of formula (a) above has one or more hydrogen atoms bonded to a silicon atom in each molecule.

[0038]

[0039] In the above general formula (b), R is as described above, and n ６ n is an integer between 1 and 10, and ７ It is either 1 or 2.

[0040]

[0041] In the above general formula (c), R and R ９ As described above, r is an integer from 0 to 3, and R １０ This is a monovalent hydrocarbon group having 1 to 10 carbon atoms, which may have a hydrogen atom or an oxygen atom, and the compound of the above general formula (c) has one or more hydrogen atoms bonded to a silicon atom in one molecule.

[0042] Suitable examples of the above-mentioned hydrogen organopolysiloxanes include terminally hydrogen-methylpolysiloxanes and terminally hydrogen-methylphenylpolysiloxanes. For example, the following compounds are preferred. (In the formula, n is an integer between 20 and 100.) (In the formula, m is an integer between 1 and 10, and n is an integer between 10 and 100.)

[0043] Among the above, preferred are dicyclopentadiene type epoxy resins, copolymer compounds obtained by a hydrosilylation reaction between an alkenyl group-containing epoxy compound with a low modulus of elasticity and a hydrogen organopolysiloxane represented by the above average composition formula (4).

[0044] [(B) Phenolic Curing Agent] In the present invention, the (B) phenolic curing agent may be any conventionally known phenolic resin curing agent. Examples include phenol novolac resin, naphthalene ring-containing phenolic resin, triphenol alkane type resin, phenol aralkyl type phenolic resin, aralkyl type phenolic resin, biphenyl skeleton-containing aralkyl type phenolic resin, biphenyl type phenolic resin, dicyclopentadiene type phenolic resin, alicyclic phenolic resin, heterocyclic phenolic resin, naphthalene ring-containing phenolic resin, bisphenol A, bisphenol F, etc. These curing agents may be used individually or in combination of two or more. In the present invention, the mixing ratio of (A) epoxy resin and (B) phenolic curing agent is not particularly limited, but it is preferable that the molar ratio of phenolic hydroxyl groups in the (B) phenolic curing agent that are reactive with epoxy to 1 mole of epoxy groups in the (A) epoxy resin is in the range of 0.5 to 1.5, and more preferably in the range of 0.8 to 1.2.

[0045] [(C) Inorganic Filler] In the present invention, the inorganic filler (C) is not particularly limited, and inorganic fillers that are normally incorporated into epoxy resin compositions can be used. Examples include silicas such as fused silica and crystalline silica, spherical cristobalite, alumina, magnesium oxide, silicon nitride, aluminum nitride, boron nitride, titanium oxide, and glass fibers. These may be used individually or in combination of two or more. The average particle size and shape of these inorganic fillers are not particularly limited, but from the viewpoint of moldability and fluidity, the average particle size is preferably 5 to 40 μm, and spherical fused silica, spherical alumina, a combination of spherical fused silica and crushed fused silica, a combination of spherical fused silica and spherical alumina, a combination of spherical fused silica and crystalline silica, or a combination of spherical crystalline silica and magnesium oxide are desirable. The average particle size can be measured as the cumulative volume-based average value (or median diameter) in particle size distribution measurement by laser diffraction. Furthermore, it is preferable that the inorganic filler is pre-surface-treated with a coupling agent such as a silane coupling agent or a titanate coupling agent in order to strengthen the bonding strength with the resin. As such a coupling agent, it is preferable to use silane coupling agents such as epoxysilanes like γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, and β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, or aminosilanes like N-β(aminoethyl)-γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, and N-phenyl-γ-aminopropyltrimethoxysilane. The amount of coupling agent used for surface treatment and the surface treatment method may follow conventionally known methods and are not particularly limited.

[0046] (C) The amount of inorganic filler added is preferably 200 to 1,000 parts by mass, particularly 400 to 900 parts by mass, per 100 parts by mass of the total amount of (A) epoxy resin and (B) phenolic curing agent. If the amount of (C) inorganic filler is within the above range, the amount of moisture absorption will be suppressed, and improved moisture-absorbing reflowability can be expected. In addition, the coefficient of linear expansion will not become too large, and thermal stress on the package will be suppressed. Furthermore, if it is below the above upper limit, there is no risk of unfilling due to decreased fluidity, wire deformation, or increased thermal stress due to improved elastic modulus.

[0047] [(D) Organosilicon Compound] The organosilicon compound that is component (D) of the present invention is characterized by the use of two organosilicon compounds, (D1) and (D2), described below, in combination. The organosilicon compound of component (D) contains an organooxysilyl group, which is hydrolyzed by moisture in the air to a silanol group, which reacts with semiconductor elements, lead frames and organic primers to form Si-O-Si bonds, thereby providing high adhesion.

[0048] [(D1) Epoxy Group-Containing Organosilicon Compound] The (D1) epoxy group-containing organosilicon compound of the present invention is an epoxy group-containing organosilicon compound that is one or more selected from organoxysilanes represented by the following general formula (2) and their hydrolysates, which have a hydrolyzable silyl group and an epoxy group in their molecule. (In the formula, R ３ R is an alkyl group having 1 to 4 carbon atoms independently. ４ (The group is independently selected from alkyl groups having 1 to 20 carbon atoms, aryl groups having 6 to 10 carbon atoms, aralkyl groups having 7 to 10 carbon atoms, alkenyl groups having 2 to 10 carbon atoms, and alkoxy groups having 1 to 20 carbon atoms, where n is an integer from 1 to 3 and m is an integer from 1 to 12.)

[0049] In the above general formula (2), R ３ R is an alkyl group having 1 to 4 carbon atoms, independently. ４This group is independently selected from an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aralkyl group having 7 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, and an alkoxy group having 1 to 20 carbon atoms. The compound represented by the above general formula (2) is more preferably the one shown in the following general formula (6), and one or more of these can be used as organosilicon compounds. (In the formula, R ３ (,n is the same as above, and Me is a methyl group.)

[0050] The epoxy group in the above general formula (2) reacts with both the epoxy resin of component (A) and the phenolic curing agent of component (B) to form a strong bond.

[0051] Furthermore, the organosilicon compound of component (D1) can be hydrolyzed beforehand to improve its adhesion to semiconductor devices and lead frames. The hydrolyzed product can be obtained, for example, by adding 0.2 to 4 moles of deionized water to 1 mole of the organosilicon compound represented by the general formula (2) above, and shaking it in a shaker at 25°C until it becomes clear.

[0052] [Organosilicon compounds having (D2) S-Si bonds] The organosilicon compounds having (D2) S-Si bonds of the present invention are organoxysilanes represented by the following general formula (3), and are organosilicon compounds having S-Si bonds. (In the formula, R ３ , R ４ n and m are the same as in equation (2) above, and R ５ (These are independently C1-C10 alkyl groups, C6-C10 aryl groups, or C1-C20 alkoxy groups.)

[0053] Generally, mercapto groups exhibit excellent adhesion to metal lead frames, especially silver plating, but they are also functional groups that react with epoxy groups. Therefore, when used in combination with component (D1) above, the mercapto groups, which are effective for bonding to the metal lead frame, often react first with the epoxy groups of component (D1), resulting in a lack of the expected effect. The S-Si bond shown in general formula (3) above exhibits high adhesion to metal lead frames even in the presence of epoxy groups because the bond dissociates at the molding temperature, revealing the mercapto group.

[0054] Unlike component (D1) mentioned above, component (D2) undergoes hydrolysis, which dissociates the S-Si bond. Therefore, pre-hydrolysis is undesirable because it causes the mercapto group to be expressed first, thus diminishing the effect of adding component (D2).

[0055] As the compound represented by the general formula (3) above, those shown as structural formulas (7) to (12) below are more preferred, and one or more of these can be used as organosilicon compounds. (In the formula, R ３ n is the same as above, Me is a methyl group, and Et is an ethyl group.

[0056] In the above general formulas (2) and (3), R ３ Examples of alkyl and aryl groups include methyl, ethyl, propyl, butyl, and phenyl groups, with methyl and ethyl groups being preferred among them.

[0057] The total amount of (D1) and (D2), i.e., the content of component (D), is preferably 0.03 to 1% by mass relative to the total amount of the resin composition. When it is 0.03% by mass or more, the moisture absorption and reflowability are sufficiently improved by using the semiconductor encapsulation resin composition of the present invention, and when it is 1% by mass or less, there are no problems with the moldability of the semiconductor encapsulation resin composition, and a good molded product can be obtained, which is preferable.

[0058] Furthermore, the blending ratio of (D1) and (D2) is preferably 0.2 to 2.0, and more preferably 0.5 to 1.0, of the amount of (D2) per 1 part of the amount of (D1).

[0059] The resin composition of the present invention may further contain, depending on the purpose of the present invention, a curing accelerator, a mold release agent, a flame retardant, an ion trapping agent, a flexibility imparter, and other additives.

[0060] The curing accelerator is not particularly limited as long as it accelerates the curing reaction. Examples of curing accelerators include phosphorus compounds such as triphenylphosphine, tributylphosphine, tri(p-methylphenyl)phosphine, tri(p-nonylphenyl)phosphine, triphenylphosphine-triphenylborane, tetraphenylphosphine-tetraphenylborate, tetraphenylphosphine-tetra(p-methylphenyl)borate, or adducts of triphenylphosphine and p-benzoquinone; tertiary amine compounds such as triethylamine, benzyldimethylamine, α-methylbenzyldimethylamine, and 1,8-diazabicyclo[5.4.0]undecene-7; and imidazole compounds such as 2-methylimidazole, 2-phenylimidazole, and 2-phenyl-4-methylimidazole; salts of 2-phenylimidazole and trimellitic anhydride; N'-[3-[[[(dimethylamino)carbonyl]amino]methyl]-3,5,5-trimethylcyclohexyl]-N,N-dimethylurea; and 2:3-phenyl-1,1-dimethylurea. These curing accelerators can be used individually or in combination of two or more. They may also be used by impregnating porous silica with them or by coating it with a thermoplastic resin such as polymethyl methacrylate.

[0061] Examples of release agents include waxes such as carnauba wax, rice wax, polyethylene, polyethylene oxide, montanic acid, ester compounds of montanic acid with saturated alcohol, 2-(2-hydroxyethylamino)-ethanol, ethylene glycol, glycerin, etc.; stearic acid, stearic acid esters, stearic acid amide, ethylenebisstearic acid amide, copolymers of ethylene and vinyl acetate, etc., which may be used individually or in combination of two or more.

[0062] Examples of flame retardants include halogenated epoxy resins, phosphazene compounds, silicone compounds, zinc molybdate-supported talc, zinc molybdate-supported zinc oxide, aluminum hydroxide, magnesium hydroxide, molybdenum oxide, and antimony trioxide. These flame retardants may be used individually or in combination of two or more, but from the viewpoint of environmental impact and ensuring fluidity, phosphazene compounds, zinc molybdate-supported zinc oxide, molybdenum oxide, aluminum hydroxide, and magnesium hydroxide are preferably used.

[0063] Examples of ion trapping agents include hydrotalcite compounds, bismuth compounds, and zirconium compounds, which may be used individually or in combination of two or more.

[0064] Examples of flexibility-imparting agents include silicone compounds such as silicone oil, silicone resin, silicone-modified epoxy resin, and silicone-modified phenolic resin, as well as thermoplastic elastomers such as styrene resin and acrylic resin. These may be used individually or in combination of two or more types.

[0065] The epoxy resin composition for semiconductor encapsulation of the present invention can be manufactured, for example, as follows: (A) epoxy resin, (B) phenolic curing agent, (C) inorganic filler, (D) organosilicon compound, and other materials are each blended in predetermined amounts, thoroughly and uniformly mixed using a mixer or the like, then subjected to a melt-mixing treatment using a hot roll, kneader, extruder, etc., followed by cooling and solidification, and then crushed to an appropriate size. The resulting cured product can be used as a molding material. It can also be further compressed into tablets. The cured product of the epoxy resin composition for semiconductor encapsulation of the present invention is effective as an encapsulating resin for semiconductor devices such as transistor type, module type, DIP type, SO type, and flat pack type. It is particularly suitable for semiconductor devices in which the semiconductor element is a power semiconductor, and is suitable when the semiconductor device is a surface mount type.

[0066] The method for encapsulating semiconductor devices using the epoxy resin composition for semiconductor encapsulation of the present invention is not particularly limited, and conventional molding methods, such as transfer molding and injection molding, may be used. Transfer molding is particularly preferred. The molding (curing) conditions for the composition of the present invention are not particularly limited, but 160 to 190°C for 90 to 300 seconds is preferred. Furthermore, post-curing at 170 to 250°C for 2 to 16 hours is preferred.

[0067] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[0068] The materials used in the examples and comparative examples are shown below.

[0069] (A) Epoxy resin Epoxy resin 1: Compound represented by the following structural formula (13) (EPPN-502H, manufactured by Nippon Kayaku Co., Ltd.) (In the formula, n is between 0 and 10.) Epoxy resin 2: Compound represented by the following structural formula (14) (FAE-2500, manufactured by Nippon Kayaku Co., Ltd.) (In the formula, n is 0 to 10, Me is a methyl group, and tBu is a tert-butyl group.) Epoxy resin 3: Compound represented by the following structural formula (15) (FAE-2500ST, manufactured by Nippon Kayaku Co., Ltd.) (In the formula, n is 0 to 10, Me is a methyl group, and iPr is an isopropyl group.) Other epoxy resins Epoxy resin 4: Copolymer of an alkenyl group-containing epoxy compound synthesized according to the synthesis example below and a hydrogen organopolysiloxane

[0070] [Synthesis Example] In a 1-liter four-necked flask equipped with a reflux condenser, thermometer, stirrer, and dropping funnel, 200 g of phenol novolac resin modified with allyl glycidyl ether (phenol equivalent 125, allyl equivalent 1,100), 800 g of chloromethyloxirane, and 0.6 g of cetyltrimethylammonium bromide were placed and heated, and stirred and mixed at 110°C for 3 hours. This was cooled to 70°C, and the pressure was reduced to 160 mmHg. Then, 128 g of a 50% aqueous solution of sodium hydroxide was added dropwise over 3 hours while azeotropically dehydrating. The resulting contents were reduced in pressure to remove the solvent, and then dissolved in a mixed solvent of 300 g of methyl isobutyl ketone and 300 g of acetone. After washing with water, the solvent was removed under reduced pressure to obtain an allyl group-containing epoxy resin (allyl equivalent 1590, epoxy equivalent 190). This epoxy resin was mixed with 170 g of methyl isobutyl ketone, 330 g of toluene, and 0.07 g of a 2% platinum-concentrated 2-ethylhexanol-modified chloroplatinic acid solution. Azeotropic dehydration was performed for 1 hour, and 133 g of organohydrogenpolysiloxane represented by the following structural formula (16) was added dropwise over 30 minutes at reflux temperature. The mixture was then stirred and reacted at the same temperature for 4 hours. The resulting contents were washed with water, and the solvent was removed under reduced pressure to obtain a white-yellow opaque solid copolymer. The epoxy equivalent was 280, the ICI melt viscosity at 150°C was 800 cP, the silicon content was 31%, and the epoxy equivalent was 323. (In the formula, n = 100, and in the above average composition formula (4), R = methyl group, a = 0.02, and b = 0.98.) Epoxy resin 5: Dicyclopentadiene type epoxy resin (HP-7200, manufactured by DIC: for comparison) Epoxy resin 6: Biphenyl type epoxy resin (YX-4000K, manufactured by Mitsubishi Chemical: for comparison)

[0071] (B) Phenolic resin curing agent Phenolic resin 1: Phenolic novolac (TD-2093Y, manufactured by DIC) Phenolic resin 2: Triphenol alkane type (MEH-7500, manufactured by UBE) Phenolic resin 3: Phenolic aralkyl (MEHC-7800SS, manufactured by UBE)

[0072] (C) Inorganic fillers: Spherical fused silica (manufactured by Ryusen, average particle size = 15 μm), Spherical fused alumina (manufactured by Resonac, average particle size = 30 μm)

[0073] (D) Silicon compound: Compound represented by the above general formula (2) (D1) Silicon compound 1: Compound represented by the following structural formula (17) (KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd.) (In the formula, Me is a methyl group.) Hydrolysis product of silicon compound 1: A compound obtained by adding 3 moles of deionized water to 1 mole of silicon compound 1 represented by the above structural formula (17) and shaking at room temperature for 2 hours. Compound (D2) represented by the above general formula (3) Silicon compound 2: A compound represented by the following structural formula (18) (X-12-1056MS, manufactured by Shin-Etsu Chemical Co., Ltd.) (In the formula, Me is a methyl group.) Silicon compound 3: Compound represented by the following structural formula (19) (X-12-1056ES, manufactured by Shin-Etsu Chemical Co., Ltd.) (In the formula, Me is a methyl group and Et is an ethyl group.) Other silicon compounds Silicon compound 4: γ-aminopropyltriethoxysilane (KBE-903, manufactured by Shin-Etsu Chemical: for comparison) Silicon compound 5: γ-mercaptopropyltrimethoxysilane (KBM-803P, manufactured by Shin-Etsu Chemical: for comparison)

[0074] Other components: Ion trapping agent: DHT-4A-2 (manufactured by Toagosei Co., Ltd.) Release agent: TOWAX-131 (manufactured by Toa Kasei Co., Ltd.) Pigment: Denka Black (manufactured by Denka Co., Ltd.) Curing catalyst 1: Salt of 2-phenylimidazole and trimellitic anhydride (2PZ-TMA, manufactured by Shin-Etsu Chemical Co., Ltd.) Adduct of triphenylphosphine and p-benzoquinone (CAT-MBA, manufactured by Shin-Etsu Chemical Co., Ltd.) Curing catalyst 2: Adduct of triphenylphosphine and p-benzoquinone (CAT-MBA, manufactured by Shin-Etsu Chemical Co., Ltd.)

[0075] (Production of epoxy resin composition for semiconductor encapsulation) <Examples 1 to 8 and Comparative Examples 1 to 5> Each component ((A) to (D) and other components) was blended in the amounts shown in Table 1, mixed in a blender for 5 minutes to homogenize, then kneaded and melted in a kneader heated to 80°C and extruded, cooled, and then pulverized to a predetermined particle size in a pulverizer to obtain a granular epoxy resin composition for semiconductor encapsulation.

[0076] The obtained epoxy resin compositions were evaluated as described below ((a) to (d)). The results are shown in Table 1.

[0077] (a) Each 150°C electrically insulating composition was transfer molded at 175°C for 120 seconds under a molding pressure of 6.9 MPa, and then post-cured at 180°C for 4 hours to obtain a hardened disc with a thickness of 2 mm and a diameter of 90 mm. In accordance with JIS K6911, the volume resistivity was determined using an insulation resistance meter (B2985A, Keysight Technologies) in a 150°C atmosphere.

[0078] (i) A 10 mm square Si diode chip was bonded to a moisture-absorbing reflowable copper alloy lead frame TO-247 with AuSn eutectic solder. The package was formed at a mold temperature of 175°C, an injection pressure of 6.9 MPa, and a curing time of 120 seconds, followed by post-curing at 180°C for 4 hours. The formed packages were examined for cracks and delamination inside the package using an ultrasonic flaw detection device, and 10 packages without cracks or delamination were produced.

[0079] Following this, the packages underwent a moisture absorption treatment at 85°C x 60% RH for 168 hours, and then reflow processing was performed in an IR reflow oven at a maximum temperature of 265°C. After this, the inside of the package was inspected using an ultrasonic inspection device to check for delamination and crack defects on the copper alloy lead frame surface and diode chip portion.

[0080] (c) A 10 mm square silicon diode chip was bonded to a copper alloy lead frame TO-247, which was fully silver-plated and hygroscopic to a silver-plated lead frame, using gold-tin eutectic solder. The package was formed at a mold temperature of 175°C, an injection pressure of 6.9 MPa, and a curing time of 120 seconds, followed by post-curing at 180°C for 4 hours. The formed packages were examined for cracks and delamination inside the package using an ultrasonic flaw detection device, and 10 packages without cracks or delamination were produced.

[0081] Following this, the packages underwent a moisture absorption treatment at 85°C x 60% RH for 168 hours, and then reflow processing was performed in an IR reflow oven at a maximum temperature of 265°C. After this, the inside of the packages was inspected using an ultrasonic inspection device to check for delamination and crack defects on the silver-plated lead frame surface and diode chip portion.

[0082] (e) Moisture-absorbing reflowability with organic primer-coated copper lead frame 0.18 g of KBE-903 was added to a solution of 171 g of ethanol and 9 g of water and mixed, and allowed to stand for 12 hours to prepare the organic primer solution. A 10 mm square silicon diode chip was joined to a copper alloy lead frame TO-247 with gold-tin eutectic solder, and then the organic primer solution was applied with an air spray gun. Heat treatment was performed at 80°C for 1 hour, followed by 180°C for 1 hour. Then, molding was performed at a mold temperature of 175°C, injection pressure of 6.9 MPa, and curing time of 120 seconds, followed by post-curing at 180°C for 4 hours. The molded packages were examined for cracks and delamination inside the package using an ultrasonic flaw detector, and 10 packages without cracks or delamination were produced.

[0083] Following this, the packages underwent a moisture absorption treatment at 85°C × 60% RH for 168 hours, and then reflow processing was performed in an IR reflow oven at a maximum temperature of 265°C. After this, the inside of the packages was observed using an ultrasonic inspection device to check for delamination and crack defects on the organic primer-coated lead frame surface and diode chip portion. These results are shown in Table 1.

[0084]

[0085] As shown in Table 1 above, in Examples 1 to 8 using the epoxy resin composition for semiconductor encapsulation of the present invention, it was confirmed that the volume resistivity at 150°C was high and that defects after moisture absorption reflow hardly occurred. On the other hand, in Comparative Examples 1 and 3, which do not contain component (D2) of the present invention, and Comparative Example 2, which does not contain component (D1), many defects were observed after moisture absorption reflow, and in Comparative Examples 4 and 5, which do not contain component (A) of the present invention, it was confirmed that the electrical insulation properties were inferior. Therefore, according to the present invention, when applied to a surface mount package equipped with a power semiconductor element, it is possible to provide a power semiconductor device with excellent reliability, which is industrially useful.

[0086] This specification includes the following embodiments: [1]: An epoxy resin composition for semiconductor encapsulation, characterized by comprising the following components (A) to (D): (A) an epoxy resin represented by the following general formula (1) (In the formula, R １ R is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. ２ (1) represents a hydrogen atom or a methyl group. n is an integer from 0 to 10. ) (B) Phenolic curing agent (C) Inorganic filler (D) Organosilicon compounds containing the following (D1) and (D2) (D1) Epoxy group-containing organosilicon compounds which are one or more selected from organoxysilanes represented by the following general formula (2) and their hydrolysates, (In the formula, R ３ R is an alkyl group having 1 to 4 carbon atoms independently. ４ (D2) An organoxysilane represented by the following general formula (3), which is an organosilicon compound having an S-Si bond. (In the formula, R ３ , R ４ n and m are the same as in equation (2) above, and R ５ (These are independently C1-C10 alkyl groups, C6-C10 aryl groups, or C1-C20 alkoxy groups.) [2]: The epoxy resin composition for semiconductor encapsulation according to [1], characterized in that the (D1) component is a hydrolysate of the general formula (2). [3]: A semiconductor device characterized by being encapsulated with a cured product of the epoxy resin composition for semiconductor encapsulation according to [1] or [2]. [4]: ​​The semiconductor device according to [3], characterized in that the semiconductor device is a power semiconductor device. [5]: The semiconductor device according to [3] or [4], characterized in that the semiconductor device is a surface mount type.

[0087] It should be noted that the present invention is not limited to the embodiments described above. The embodiments described above are illustrative, and any configuration that is substantially identical to the technical idea described in the claims of the present invention and achieves similar effects is included within the technical scope of the present invention.

Claims

1. A semiconductor encapsulation epoxy resin composition, characterized by comprising the following components (A) to (D). (A) An epoxy resin represented by the following general formula (1) (In the formula, R ５ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R ２ is a hydrogen atom or a methyl group. n is an integer from 0 to 10.) (B) A phenolic curing agent (C) An inorganic filler (D) An organosilicon compound containing the following (D1) and (D2) (D1) An epoxy group-containing organosilicon compound which is one or more selected from organooxysilanes represented by the following general formula (2) and their hydrolyzates, (In the formula, R ３ is independently an alkyl group having 1 to 4 carbon atoms, and R ４ is independently a group selected from an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aralkyl group having 7 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, and an alkoxy group having 1 to 20 carbon atoms. n is an integer from 1 to 3, and m is an integer from 1 to 12.) (D2) An organooxysilane represented by the following general formula (3), which is an organosilicon compound having an S-Si bond (In the formula, R ３ , R ４ , n and m are the same as those in the above formula (2), and R ５ is independently an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, or an alkoxy group having 1 to 2 decades.) 2. The epoxy resin composition for semiconductor encapsulation according to claim 1, characterized in that the (D1) component is a hydrolyzed product of the general formula (2).

3. A semiconductor device characterized by being sealed with a cured product of the epoxy resin composition for semiconductor encapsulation described in claim 1.

4. The semiconductor device according to claim 3, characterized in that the semiconductor device is a power semiconductor device.

5. The semiconductor device according to claim 3 or 4, characterized in that the semiconductor device is of the surface mount type.

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