JP2016074805A - Resin composition for sealing semiconductor and semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin composition for sealing a semiconductor that can produce a cured product excellent in heat resistance, thermal decomposition stability and mechanical strength retention, is excellent in flowability during molding process and is suitable for use as sealing material for a power semiconductor device and to provide a resin cured product for sealing a semiconductor.SOLUTION: The resin composition for sealing a semiconductor contains as essential components a biphenylaralkyl type epoxy resin, a triphenol methane type curing agent (a repeating number of 0.2 to 4.0), a phenol novolak type curing agent (a repeating number of 1 or 2), a curing catalyst and an organic filler in a specific ratio thereof.SELECTED DRAWING: None

Description

  The present invention relates to a resin composition for semiconductor encapsulation and a semiconductor device, and more specifically, it provides a cured resin for semiconductor encapsulation excellent in heat resistance and thermal decomposition stability, and adhesion to a metal wiring of a semiconductor element. The present invention relates to a semiconductor sealing resin composition and a semiconductor device that are particularly excellent for power semiconductor sealing.

  Epoxy resins are used in a wide range of industrial applications. As an example, there is an application as a sealing material in a semiconductor device, but the required performance in the semiconductor device has become increasingly sophisticated in recent years, and the required power density has become a region that is difficult to reach with conventional Si devices. . Under such circumstances, SiC power devices can be cited as devices that are expected to have higher power density and are being developed in recent years. To achieve higher power density, the temperature of the chip surface during operation Reaches 250 ° C. Therefore, development of a sealing material that can withstand the temperature and can maintain the physical properties for 1000 hours or more is strongly desired.

  Under such circumstances, Patent Document 1 discloses an epoxy resin, an epoxy resin composition, and a cured product having a biphenol-biphenyl aralkyl structure, and shows that it is excellent in heat resistance, moisture resistance, and thermal conductivity. Has been. However, even when the epoxy resin disclosed in Patent Document 1 is used as described above, only a cured product having a glass transition temperature of about 200 ° C. is obtained when phenol novolac is used as a curing agent by a normal molding method. Absent. Therefore, the subject that the characteristic of the sealing material for high heat resistant SiC power devices which can endure a high operating temperature of 250 degreeC cannot be satisfied occurred. Moreover, in patent document 1, long-term thermal stability required for the sealing material for SiC power devices is not described. Patent Document 2 discloses triphenolmethane polyhydric hydroxy resin and phenol aralkyl as curing agents, but the adhesion to the substrate has not been studied, and there is a problem with the adhesion to the substrate. There is a possibility of causing a malfunction in the semiconductor device.

WO2011 / 0774517 pamphlet WO2014 / 066512 Pamphlet

  Accordingly, an object of the present invention is to obtain a resin-cured resin for semiconductor encapsulation excellent in high Tg property (heat resistance) and adhesion to the metal wiring of the element, and also excellent in fluidity during molding. Then, it is providing the resin composition for semiconductor sealing suitable for using as a power device sealing material.

（但し、ｎは数平均値として０．２〜４．０を示し、Ｇはグリシジル基を示す。）

（但し、Ｒ、Ｒ₁、は水素原子又は炭素数１〜６の炭化水素基を示し、ｌは０又は１の数を、ｍは数平均値として０．２〜４．０を示す。） That is, the present invention is a resin composition for semiconductor encapsulation containing an epoxy resin, a phenolic curing agent, a curing catalyst and an inorganic filler, and the biphenylaralkyl type represented by the following general formula (1) as an epoxy resin The epoxy resin is contained in an amount of 80 wt% or more based on the total amount of the epoxy resin, and a triphenolmethane type curing agent represented by the following general formula (2) is contained as a phenolic curing agent in an amount of 40 to 90 wt% based on the total amount of the curing agent. The phenol novolak-type curing agent represented by the following general formula (3) is contained in an amount of 10 to 60 wt% with respect to the total amount of the curing agent, and the phenolic curing agents of the general formulas (2) and (3) are combined. 80% by weight or more based on the total amount, and the spiral flow of the composition at 175 ° C. is 110 cm or more. A epoxy resin composition.

(However, n shows 0.2-4.0 as a number average value, G shows a glycidyl group.)

(However, R and R ₁ represent a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms, 1 represents a number of 0 or 1, and m represents a number average value of 0.2 to 4.0.)

Moreover, this invention is the epoxy resin hardened | cured material for semiconductor sealing formed by shape | molding such an epoxy resin composition at the shaping | molding temperature of 100 to 200 degreeC, and carrying out post-curing at 200 to 300 degreeC. After the molding and curing, a cured product having a glass transition point (Tg) of 230 ° C. or more and an adhesion strength of 3.0 MPa or more with the metal wiring of the semiconductor element can be obtained.
Furthermore, a SiC power semiconductor device in which the semiconductor element sealed with such a cured epoxy resin is a SiC power semiconductor element.

  The cured product obtained by using the epoxy resin composition for semiconductor encapsulation of the present invention has high Tg property and excellent adhesion to the metal wiring of the semiconductor element, and this resin composition has excellent flow during molding. (Spiral flow). Therefore, the epoxy resin composition of the present invention can be suitably used particularly for the application of a sealing material for SiC power semiconductors.

  Hereinafter, the present invention will be described in detail. The resin composition for encapsulating a semiconductor of the present invention contains the epoxy resin of the general formula (1), the phenolic curing agent, the curing catalyst and the inorganic filler of the general formulas (2) and (3).

（但し、ｎは数平均値として０．２〜４．０を示す。）

（但し、Ｘは水酸基、ハロゲン原子又は炭素数１〜６のアルコキシ基を示す。） The epoxy resin represented by the general formula (1), which is an essential component of the resin composition for semiconductor encapsulation of the present invention, is a polyvalent hydroxy resin represented by the following general formula (a) and epichlorohydrin. Can be made to react. And this polyhydric hydroxy resin can be manufactured by making biphenols and the biphenyl type condensing agent represented by the following general formula (b) react.

(However, n indicates a number average value of 0.2 to 4.0.)

(However, X shows a hydroxyl group, a halogen atom, or a C1-C6 alkoxy group.)

  Examples of the biphenols used as the raw material for synthesizing the polyvalent hydroxy resin include 4,4′-dihydroxybiphenyls. These bifunctional phenolic compounds may be substituted with a hydrocarbon group having 1 to 6 carbon atoms. Examples of the substituent include a methyl group, an ethyl group, an isopropyl group, an allyl group, a tertiary butyl group, an amyl group, a cyclohexyl group, and a phenyl group. These dihydroxybiphenyls may be used alone or in combination of two or more.

In the general formula (b), X represents a hydroxyl group, a halogen atom or an alkoxy group having 1 to 6 carbon atoms. Specific examples of the biphenyl condensing agent represented by the general formula (b) include 4,4′-bishydroxymethylbiphenyl, 4,4′-bischloromethylbiphenyl, 4,4′-bisbromomethylbiphenyl, 4,4. Examples include '-bismethoxymethylbiphenyl and 4,4'-bisethoxymethylbiphenyl. From the viewpoint of reactivity, 4,4′-bishydroxymethylbiphenyl and 4,4′-bischloromethylbiphenyl are preferable. From the viewpoint of reducing ionic impurities, 4,4′-bishydroxymethylbiphenyl, 4 4,4'-bismethoxymethylbiphenyl is preferred.
In general formulas (1), (a), and (b), common symbols have the same meanings unless otherwise specified.

  As for the molar ratio at the time of making it react, 1 mol or less of a biphenyl-type condensing agent is preferable with respect to 1 mol of 4,4′-dihydroxybiphenyl, and generally ranges from 0.1 to 0.7 mol. Preferably it is the range of 0.2-0.5 mol. If it is less than this, the crystallinity becomes strong, the solubility in epichlorohydrin when synthesizing the epoxy resin is lowered, the melting point of the obtained epoxy resin is increased, and the handleability is lowered. On the other hand, if the amount is larger than this, the crystallinity of the resin is lowered and the softening point and the melt viscosity are increased, which hinders handling workability and moldability.

  In addition, when chloromethylbiphenyl is used as the condensing agent, the reaction can be carried out in the absence of a catalyst, but usually the condensation reaction is carried out in the presence of an acidic catalyst. The acidic catalyst can be appropriately selected from known inorganic acids and organic acids. For example, mineral acids such as hydrochloric acid, sulfuric acid, phosphoric acid, formic acid, oxalic acid, trifluoroacetic acid, p-toluenesulfonic acid, metasulfone Examples thereof include organic acids such as acid and trifluorometasulfonic acid, Lewis acids such as zinc chloride, aluminum chloride, iron chloride, and boron trifluoride, and solid acids.

  This reaction is carried out at 10 to 250 ° C. for 1 to 20 hours. In the reaction, alcohols such as methanol, ethanol, propanol, butanol, ethylene glycol, methyl cellosolve and ethyl cellosolve, and aromatic compounds such as benzene, toluene, chlorobenzene and dichlorobenzene can be used as a solvent. . After completion of the reaction, the solvent or water and alcohol produced by the condensation reaction are removed as necessary.

  A method for producing the biphenyl aralkyl type epoxy resin represented by the general formula (1) by the reaction of the polyvalent hydroxy resin represented by the general formula (a) and epichlorohydrin will be described. This reaction can be performed in the same manner as a well-known epoxidation reaction.

  For example, after the polyvalent hydroxy resin represented by the general formula (a) is dissolved in excess epichlorohydrin, it is 50 to 150 ° C., preferably 60 in the presence of an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide. The method of making it react for 1 to 10 hours in the range of -120 degreeC is mentioned. In this case, the amount of epichlorohydrin used is in the range of 0.8 to 2 mol, preferably 0.9 to 1.2 mol, relative to 1 mol of the hydroxyl group in the polyvalent hydroxy resin. Excess epichlorohydrin was distilled off after completion of the reaction, the residue was dissolved in a solvent such as toluene and methyl isobutyl ketone, filtered, washed with water to remove inorganic salts, and then the solvent was distilled off to remove the general formula ( The target epoxy resin represented by 1) can be obtained. When performing the epoxidation reaction, a catalyst such as a quaternary ammonium salt may be used.

  The purity of the biphenyl aralkyl type epoxy resin represented by the general formula (1), in particular the amount of hydrolyzable chlorine, is preferably smaller than the viewpoint of improving the reliability of the applied electronic component. Although it does not specifically limit, Preferably it is 1000 ppm or less, More preferably, it is 500 ppm or less. In addition, the hydrolyzable chlorine as used in the field of this invention means the value measured by the following method. Specifically, 0.5 g of sample was dissolved in 30 ml of dioxane, 1N-KOH, 10 ml was added, and the mixture was boiled and refluxed for 30 minutes. Is a value obtained by performing

  The blending amount of the biphenyl aralkyl type epoxy resin represented by the general formula (1) in the semiconductor sealing resin composition of the present invention is preferably 0.1 wt% to 28 wt%, and preferably 3 wt% to 16 wt%. %. If the blending amount of the epoxy resin of the general formula (1) is less than 0.1 wt%, the heat resistance and thermal decomposition stability of the cured product is not sufficiently improved. Conversely, if it exceeds 28 wt%, the equivalent balance of epoxy group and hydroxyl group The heat resistance, mechanical strength, etc. of the cured product are reduced.

ここで、Ｒは水素原子又は炭素数１〜６の炭化水素基を示し、ｌは０〜２の数を示す。

ここで、Ｒ、Ｒ₁、は水素原子又は炭素数１〜６の炭化水素基を示し、ｌは０又は１の数を、ｍは数平均値として０．２〜４．０を示す。 As a hardening | curing agent mix | blended with the resin composition for semiconductor sealing of this invention, it is necessary to use together the specific phenol type hardening | curing agent represented by General formula (2) and (3) in a specific ratio. That is, for the purpose of improving the fluidity at the time of molding and the adhesion to the semiconductor element substrate, the triphenolmethane type curing agent represented by the general formula (2) is 40 to 90 wt% with respect to the total amount of the curing agent. Preferably, the phenol novolac type curing agent represented by 50 to 80 wt% and the general formula (3) is contained in an amount of 10 to 60 wt%, more preferably 20 to 50 wt%, based on the total amount of the curing agent, and these general formulas (2 ) And (3) together with the phenolic curing agent, it is essential to contain 80 wt% or more, more preferably 90 wt% or more based on the total amount of the curing agent. By using these two types of phenolic curing agents in combination at a specific ratio, a particularly excellent effect is shown in a field where high adhesion to a metal wiring of a semiconductor element is required as a semiconductor sealing material.

Here, R shows a hydrogen atom or a C1-C6 hydrocarbon group, and l shows the number of 0-2.

Here, R and R ₁ represent a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms, l represents a number of 0 or 1, and m represents a number average value of 0.2 to 4.0.

  By using 40 to 90 wt% of the triphenolmethane type curing agent represented by the general formula (2) with respect to the total amount of the curing agent, a high Tg property of 200 ° C. or higher required for a sealant for power devices is found. In addition, high thermal decomposition stability is exhibited by maintaining the glass state during a long-term heat test, and the phenol novolac type curing agent represented by the general formula (3) is used in an amount of 10 to 60 wt% with respect to the total amount of the curing agent. Therefore, it is considered that higher adhesion strength is expressed by the introduction of an appropriate cross-linking structure, and the phenolic curing agents of the general formulas (2) and (3) are used in an amount of 80 wt% or more based on the total amount of the curing agent. By doing so, the resin composition for semiconductor sealing which can be especially used as a SiC power device sealing material can be provided.

  Among the phenolic curing agents used in the epoxy resin composition of the present invention, the triphenolmethane type polyvalent hydroxy compound represented by the general formula (2) is salicylaldehyde or p-hydroxyaldehyde and a phenolic hydroxyl group-containing compound. Can be made to react.

  Here, as the phenolic hydroxyl group-containing compound, phenol, o-cresol, m-cresol, p-cresol, 2-ethylphenol, 4-ethylphenol, 2-propylphenol, 4-propylphenol, 4-tert-butylphenol 4-pentylphenol, 4-tert-pentylphenol, 4-neopentylphenol, 2-cyclopentylphenol, 2-hexylphenol, 4-hexylphenol, and the like.

  On the other hand, the phenol novolac type polyvalent hydroxy compound represented by the general formula (3) that is essential to be used in combination at a specific ratio is a phenol novolak produced by reacting phenols with paraformaldehyde or formalin solution, Cresol novolac can be preferably used. Moreover, in General formula (3), m is 1 or more, From a viewpoint of expression of high Tg property and a solvent solubility improvement, Preferably it is 0.2-4 as an average value (number average), More preferably It is the range of 1-3. Furthermore, it is most preferable that m is 2 or 3 and 50 wt% or more is contained. If it is smaller than this, the Tg will decrease due to a decrease in the crosslinking density, and if it is larger than this, the moldability will deteriorate and the adhesion will decrease due to the increase in molecular weight.

  The compounding quantity of the whole phenolic hardening | curing agent in the epoxy resin composition for semiconductor sealing of this invention is the equivalent balance of the epoxy group in the epoxy resin represented by General formula (1), and the hydroxyl group of a phenolic hardening | curing agent. Mix in consideration. The equivalent ratio of epoxy resin and curing agent is usually in the range of 0.2 to 5.0, preferably in the range of 0.5 to 2.0, more preferably in the range of 0.8 to 1.5. It is. If it is larger or smaller than this, the curability of the resin composition for semiconductor encapsulation is lowered, and the heat resistance, mechanical strength and the like of the cured product are lowered.

  Moreover, as above-mentioned, content of the triphenolmethane type hardening | curing agent represented by General formula (2) is 40 wt%-90 wt% in a hardening | curing agent component, Preferably it is 50 wt%-80 wt%, and more Preferably it is the range of 65 wt%-75 wt%. If it is less than this, the heat resistance will be lowered, and if it is more than this, the adhesion will not be sufficiently developed.

  Further, the content of the phenol novolac type curing agent represented by the general formula (3) is 10 wt% to 60 wt% in the curing agent component as described above, preferably 20 wt% to 50 wt%, more preferably. Is in the range of 25 wt% to 35 wt%. When it is less than this, the adhesiveness is lowered, and when it is more than this, the heat resistance is not sufficiently exhibited.

  Further, in this epoxy resin composition for semiconductor encapsulation, as the curing agent component, other than the triphenolmethane type curing agent of the general formula (2) and the phenol novolak type curing agent represented by the general formula (3), Polyhydric phenols that are phenolic curing agents may be included. Examples of the polyhydric phenols include bisphenol A, bisphenol F, bisphenol S, fluorene bisphenol, hydroquinone, resorcin, catechol, biphenols, and naphthalenediol. More than trivalent typified by dihydric phenols such as 1,2,2,2-tetrakis (4-hydroxyphenyl) ethane, naphthol novolak, dicyclopentadiene type phenol resin, phenol aralkyl resin, etc. There are phenols. Furthermore, naphthols or divalent phenols such as bisphenol A, bisphenol F, bisphenol S, fluorene bisphenol, 4,4′-biphenol, 2,2′-biphenol, hydroquinone, resorcin, catechol, naphthalenediol and formaldehyde , Acetaldehyde, benzaldehyde, p-hydroxybenzaldehyde, p-xylylene glycol, p-xylylene glycol dimethyl ether, divinylbenzene, diisopropenylbenzene, dimethoxymethylbiphenyls, divinylbiphenyl, diisopropenylbiphenyls, etc. Polyphenolic compounds synthesized by reaction, biphenyl aralkyl type phenol resins obtained from phenols and bischloromethylbiphenyl, etc. . Furthermore, naphthol aralkyl resins synthesized from naphthols and paraxylylene dichloride are exemplified.

Moreover, in this epoxy resin composition for semiconductor sealing, you may mix | blend other type | system | group hardening | curing agents, such as an amine type and an acid anhydride type | system | group, in addition to a phenol type hardening | curing agent as a hardening | curing agent component. Examples of other curing agents in this case include dicyandiamide, acid anhydrides, aromatic and aliphatic amines, and one or more of these curing agents can be used in combination.
However, the amount of the curing agent other than the phenolic curing agent represented by the general formulas (2) and (3), that is, the phenolic curing agent and the non-phenolic curing agent other than the general formulas (2) and (3) is The amount of the curing agent is 20 wt% or less, and preferably 10 wt% or less.

Moreover, in addition to the biphenyl aralkyl type epoxy resin represented by General formula (1), you may mix | blend another epoxy resin as an epoxy resin component in this epoxy resin composition for semiconductor sealing. As the epoxy resin in this case, all ordinary epoxy resins having two or more epoxy groups in the molecule can be used. Examples include bisphenol A, bisphenol F, bisphenol S, fluorene bisphenol, 4,4′-biphenol, 3,3 ′, 5,5′-tetramethyl-4,4′-dihydroxybiphenyl, resorcin, naphthalenediols Trivalent or higher epoxides such as divalent phenols such as tris- (4-hydroxyphenyl) methane, 1,1,2,2-tetrakis (4-hydroxyphenyl) ethane, phenol novolak, o-cresol novolak, etc. Epoxidized products of phenols, epoxidized products of cocondensation resins obtained from dicyclopentadiene and phenols, epoxidized products of cocondensation resins obtained from cresols, formaldehyde and alkoxy-substituted naphthalenes, phenols and paraxylylene dichloride Obtained from etc. E Nord aralkyl resin epoxidized product, there phenols and bis-chloromethyl biphenyl biphenyl aralkyl type phenolic resins obtained from the epoxy compound, epoxidized naphthol aralkyl resin and the like which are synthesized from naphthols and para-xylylene dichloride and the like. These epoxy resins can be used alone or in combination of two or more.
However, the compounding quantity of the biphenyl aralkyl type epoxy resin represented by General formula (1) is 80-100 wt% in the whole epoxy resin, Preferably it is the range of 90-100 wt%.

  Furthermore, the epoxy resin composition for semiconductor encapsulation of the present invention can contain a curing catalyst. Examples of the curing catalyst include amines, imidazoles, organic phosphines, Lewis acids and the like. Specifically, 1,8-diazabicyclo (5,4,0) undecene-7, triethylenediamine, benzyldimethylamine, Tertiary amines such as ethanolamine, dimethylaminoethanol, tris (dimethylaminomethyl) phenol, 2-methylimidazole, 2-phenylimidazole, 2-ethyl-4-methylimidazole, 2-phenyl-4-methylimidazole, 2- Imidazoles such as heptadecylimidazole, organic phosphines such as tributylphosphine, methyldiphenylphosphine, triphenylphosphine, diphenylphosphine, and phenylphosphine, tetraphenylphosphonium tetraphenylborate, tetra Tetraphenyl such as phenylphosphonium / ethyltriphenylborate, tetrabutylphosphonium / tetrabutylborate, tetrasubstituted phosphonium / tetrasubstituted borate, 2-ethyl-4-methylimidazole / tetraphenylborate, N-methylmorpholine / tetraphenylborate, etc. There is boron salt. As addition amount, it is the range of 0.2-5 weight part normally with respect to 100 weight part of epoxy resins.

  As the inorganic filler, for example, silica powder such as spherical or crushed fused silica, crystalline silica, alumina powder, glass powder, or mica, talc, calcium carbonate, alumina, hydrated alumina, boron nitride, aluminum nitride, Examples thereof include silicon nitride, silicon carbide, titanium nitride, zinc oxide, tungsten carbide, and magnesium oxide. A preferable blending amount of the inorganic filler in the resin composition for semiconductor encapsulation is 70% by weight to 95% by weight, and more preferably 80% by weight to 90% by weight.

  In the epoxy resin composition for semiconductor encapsulation of the present invention, if necessary, a release agent such as carnauba wax or OP wax, a cup of 4-aminopropylethoxysilane, γ-glycidoxypropyltrimethoxysilane or the like. A coloring agent such as a ring agent or carbon black, a flame retardant such as antimony trioxide, a lubricant such as calcium stearate may be blended.

  In the epoxy resin composition for semiconductor encapsulation of the present invention, oligomers or polymer compounds such as polyester, polyamide, polyimide, polyether, polyurethane, petroleum resin, indene resin, indene-coumarone resin, phenoxy resin are modified. You may mix | blend suitably as a quality agent etc. In this case, the addition amount is usually in the range of 2 to 30 parts by weight with respect to 100 parts by weight of the epoxy resin.

  Moreover, additives, such as a pigment, a refractory agent, a thixotropic agent, a coupling agent, a fluidity improver, and an antioxidant, can also be blended in the epoxy resin composition for semiconductor encapsulation of the present invention.

  Among these, examples of the pigment include organic or inorganic extender pigments and scaly pigments. Examples of the thixotropic agent include silicon-based, castor oil-based, aliphatic amide wax, polyethylene oxide wax, and organic bentonite.

  Any method may be used for preparing the epoxy resin composition for semiconductor encapsulation of the present invention as long as various raw materials can be uniformly dispersed and mixed. As a general method, a raw material having a predetermined blending amount is used as a mixer. Examples of the method include sufficient mixing by using a mixing roll, an extruder, and the like, followed by cooling and pulverization.

  The epoxy resin composition for semiconductor encapsulation of the present invention and the cured product thereof are particularly suitable for sealing power semiconductor devices.

  The epoxy resin hardened | cured material for semiconductor sealing of this invention is obtained by thermosetting the said epoxy resin composition. In order to obtain a cured product using the epoxy resin composition of the present invention, for example, methods such as transfer molding, press molding, cast molding, injection molding, and extrusion molding are applied, but from the viewpoint of mass productivity. Transfer molding is preferred.

  The epoxy resin composition for semiconductor encapsulation of the present invention is molded at 100 ° C. to 200 ° C., preferably 120 ° C. to 190 ° C., more preferably 150 ° C. to 180 ° C., and then 200 ° C. to 300 ° C., preferably 220 ° C. to By post-curing at 280 ° C., more preferably 230 to 270 ° C., it can be molded and cured with good fluidity, and a cured product excellent in terms of glass transition point (Tg), mechanical strength retention and the like can be obtained. .

  The molding time is preferably 1 to 60 minutes, more preferably 1 to 10 minutes. If the molding time is long, the productivity will be poor, and if it is too short, it will be difficult to release. The post cure time is preferably 10 minutes to 10 hours, preferably 30 minutes to 8 hours, and particularly preferably 2 hours to 6 hours. When the post-cure time is short, curing does not proceed sufficiently, and sufficient characteristics such as heat resistance and mechanical properties cannot be obtained. Moreover, productivity will fall when it exceeds 10 hours.

  In the epoxy resin composition for semiconductor encapsulation of the present invention, the curing reaction proceeds even in a high post-cure temperature region where a general epoxy resin composition cannot react, and a very high glass transition point (Tg), semiconductor element A cured product having excellent adhesion to the metal wiring can be obtained.

  The epoxy resin cured product for semiconductor encapsulation of the present invention is a highly efficient power semiconductor that is expected to be applied to a hybrid vehicle or the like with the aim of improving fuel efficiency and downsizing in the future in place of a silicon semiconductor, particularly a SiC power device. It is useful for sealing (transistors, diodes, etc.), and has excellent heat resistance near 250 ° C. and adhesion to a power semiconductor substrate (nickel plating layer) as compared with conventional sealing materials.

  Hereinafter, based on a synthesis example, an Example, and a comparative example, this invention is demonstrated concretely.

Synthesis example 1
In a 1000 ml four-necked flask, 77.5 g of 4,4′-dihydroxybiphenyl, 180.8 g of diethylene glycol dimethyl ether, and 52.3 g of 4,4′-bischloromethylbiphenyl were charged, and the temperature was raised to 170 ° C. with stirring in a nitrogen stream. The reaction was allowed to warm for 2 hours. After the reaction, 123 g of diethylene glycol dimethyl ether was recovered, dissolved in 385.4 g of epichlorohydrin and 57.8 g of diethylene glycol dimethyl ether, and 69.4 g of 48% aqueous sodium hydroxide solution was added dropwise at 62 ° C. under reduced pressure (about 130 Torr) over 4 hours. . During this time, the generated water was removed from the system by azeotropy with epichlorohydrin, and the distilled epichlorohydrin was returned to the system. After completion of the dropwise addition, the reaction was continued for another hour. Thereafter, epichlorohydrin was distilled off, methyl isobutyl ketone was added, salts were removed by washing with water, filtration and washing were performed, and then methyl isobutyl ketone as a solvent was distilled off under reduced pressure to obtain 129 g of an epoxy resin. (Epoxy resin A). The epoxy equivalent of this epoxy resin A was 196. Moreover, the peak temperature in this DSC measurement result using the differential scanning calorimeter shown below for this epoxy resin A was 126 degreeC, Furthermore, the melt viscosity in 150 degreeC was 0.68 Pa.s. In addition, the measuring method of these physical-property values is as having shown below.

Examples 1-9, Comparative Examples 1-6
As an epoxy resin component, the epoxy resin A obtained in Synthesis Example 1 and as a curing agent component, two types of phenolic curing agents, that is, a triphenylmethane type polyvalent hydroxy resin represented by the general formula (2) A phenol novolak resin (manufactured by Showa Denko KK, OH equivalent 105, softening point 80 ° C.) represented by Chemical Industry Co., Ltd., OH equivalent 97.5, softening point 105 ° C.) and general formula (3) was used. Further, curing catalyst A: 2-phenyl-4,5-dihydroxymethylimidazole (product name: 2PHZ-PW, manufactured by Shikoku Kasei Co., Ltd.) was used, and spherical silica (product name: FB-8S, electrochemical) as an inorganic filler. Kogyo Co., Ltd.) was used. Furthermore, carnauba wax (product name: TOWAX171, manufactured by Toa Kasei Co., Ltd.) was added as a release agent, and carbon black (product name: MA-100, manufactured by Mitsubishi Chemical Corporation) was added as a colorant. A resin composition for semiconductor encapsulation was obtained by blending 2 and 2.

The explanation of the abbreviations in the table is as follows.
(Main agent)
Epoxy resin A; epoxy resin (curing agent) obtained in Synthesis Example 1
Curing agent A: Triphenolmethane type polyvalent hydroxy resin (TPM-100 (manufactured by Gunei Chemical Industry Co., Ltd.), OH equivalent 97.5, softening point 105 ° C.)
Curing agent B: phenol novolac type polyvalent hydroxy resin (BRG-557 (manufactured by Showa Denko KK), OH equivalent 105, softening point 80 ° C.)
(Curing catalyst)
Curing catalyst A; 2-phenyl-4,5-dihydroxymethylimidazole (product name: 2 PHZ-PW, manufactured by Shikoku Kasei Co., Ltd.)
(Inorganic filler)
Spherical silica (Product name: FB-8S, manufactured by Denki Kagaku Kogyo Co., Ltd.)
(Release agent)
Carnauba wax (Product name: TOWAX171, manufactured by Toa Kasei Co., Ltd.)
(Coloring agent)
Carbon black (Product name: MA-100, manufactured by Mitsubishi Chemical Corporation)
(Primer A)
Alkoxysilyl group-containing polyamideimide resin (Composeran H 90-2: manufactured by Arakawa Chemical Industries, Ltd.)

Moreover, using the epoxy resin composition for semiconductor encapsulation according to Examples 1 to 9 and Comparative Examples 1 to 6, the SiC power semiconductor was nickel-plated as a metal wiring. In Examples 7 to 9, primer A was used. After processing, it was sealed with the epoxy resin composition and molded under the molding conditions shown below. And after obtaining the hardened | cured material test piece (epoxy resin hardened | cured material for semiconductor sealing), it used for the various physical property measurement described below. The results are shown in Tables 1-2.
Molding condition A; molding temperature 175 ° C., 3 minutes. Post cure temperature 175 ° C., 5 hours.
Molding condition B; molding temperature 175 ° C., 3 minutes. Post cure temperature 200 ° C., 5 hours Molding condition C; molding temperature 175 ° C., 3 minutes. Post cure temperature 250 ° C, 5 hours

1) Measurement of epoxy equivalent Using a potentiometric titrator, methyl ethyl ketone was used as a solvent, a brominated tetraethylammonium acetic acid solution was added, and the potential was measured using a 0.1 mol / L perchloric acid-acetic acid solution.
2) Melt viscosity It measured at 150 degreeC using the Toa Kogyo Co., Ltd. make and the CV-1S type | mold cone plate viscometer.
3) Gel time The resin composition for semiconductor encapsulation is added onto the plate of a gelation tester (Nisshin Kagaku Co., Ltd.) that has been heated to 175 ° C., and is rotated twice per second using a fluororesin rod. The gelation time required for the semiconductor sealing resin composition to cure was examined.
4) Spiral flow Molding the resin composition for semiconductor encapsulation with a spiral flow measurement mold in accordance with the standard (EMMI-1-66) under conditions of spiral flow injection pressure (150 kgf / cm ² ) and curing time of 3 minutes. Then, the flow length was examined.
5) Glass transition point (Tg)
The Tg of the obtained cured product test piece was obtained under the condition of a temperature rising rate of 10 ° C./min using a Seiko Instruments TMA6100 type thermomechanical measuring device.
6) Adhesion strength By the pudding cup method, the adhesion strength measurement with respect to the nickel plating base material which is a metal wiring of a SiC power semiconductor element was implemented at 25 points | pieces, and the average value was made into adhesion strength. Here, the shear rate of the shear tester was 50 μm / s, the shear height was 100 μm, and the cup area was 10 mm ² .

  As is clear from Tables 1 and 2, the curing agent A of Comparative Examples 1 to 3 has a high melt viscosity and poor moldability (spiral flow), while the curing agent B of Comparative Examples 4 to 6 has a high post-cure. Even at the temperature (molding condition C), the rate of increase of the glass transition point (Tg) is low. On the other hand, the epoxy resin composition for sealing a SiC power semiconductor of this example is molded and cured with good fluidity (spiral flow), and a high post-cure temperature at which a general epoxy resin composition cannot react. Curing reaction also proceeds in the region (molding condition C), and a cured product excellent in terms of adhesion to the metal wiring (nickel plating substrate) of the SiC power semiconductor element, which has a very high glass transition point (Tg). Can be obtained. In addition, the SiC power semiconductor sealing resin composition of a present Example can also raise adhesion strength markedly by interposing a primer (Examples 7-9).

Claims (6)

A resin composition for encapsulating a semiconductor containing an epoxy resin, a phenolic curing agent, a curing catalyst, and an inorganic filler, and the total amount of the biphenylaralkyl type epoxy resin represented by the following general formula (1) as the epoxy resin The phenolic curing agent contains a triphenolmethane type curing agent represented by the following general formula (2) in an amount of 40 to 90 wt% based on the total amount of the curing agent, and the following general formula (3 10 to 60 wt% of the phenol novolak type curing agent represented by the formula (2) and 80 wt% of the total amount of the curing agent in combination with the phenolic curing agents of the general formulas (2) and (3). An epoxy resin composition for encapsulating a semiconductor, wherein the composition has a spiral flow at 175 ° C. of 110 cm or more.

(However, n shows 0.2-4.0 as a number average value, G shows a glycidyl group.)

(However, R and R ₁ represent a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms, 1 represents a number of 0 or 1, and m represents a number average value of 0.2 to 4.0.)   50-80 wt% of the triphenolmethane type curing agent represented by the general formula (2) is contained with respect to the total amount of the curing agent, and the phenol novolac type curing agent represented by the general formula (3) is based on the total amount of the curing agent. The epoxy resin composition for semiconductor encapsulation according to claim 1, comprising 20 to 50 wt% and 90 wt% or more of the phenolic curing agents of the general formulas (2) and (3).   2. The epoxy resin composition for semiconductor encapsulation according to claim 1, wherein a cured product having a glass transition point (Tg) of 230 ° C. or higher and an adhesion strength of 3.0 MPa or higher with a semiconductor element substrate can be obtained after molding and curing.   A cured epoxy resin for semiconductor encapsulation, wherein the epoxy resin composition according to claim 1 is molded at a molding temperature of 100 ° C to 200 ° C and then post-cured at 200 ° C to 300 ° C.   A semiconductor device formed by sealing a semiconductor element with the cured epoxy resin according to claim 4.   The semiconductor device according to claim 5, wherein the semiconductor element sealed with the cured epoxy resin is a SiC power semiconductor element.