JP5141125B2 - Epoxy resin composition for semiconductor encapsulation and semiconductor device - Google Patents

Description

  The present invention relates to an epoxy resin composition for semiconductor encapsulation and a semiconductor device using the same.

As a sealing method for semiconductor elements such as IC and LSI, transfer molding of an epoxy resin composition for semiconductor sealing is suitable for low-cost and mass production, and it has been used for a long time. The improvement of the characteristic has been aimed at by the improvement of the phenol resin hardening | curing agent which is. However, due to the recent trend toward smaller, lighter, and higher performance electronic devices, semiconductors have been increasingly integrated and the surface mounting of semiconductor devices has been promoted. The demand for compositions has become increasingly severe. For this reason, the problem which cannot be solved with the conventional epoxy resin composition for semiconductor sealing has also come out.
The biggest problem is that by adopting surface mounting, the semiconductor device is suddenly exposed to a high temperature of 200 ° C. or higher in the solder dipping or solder reflow process, and the moisture when moisture absorbed explosively evaporates. In particular, a phenomenon in which reliability is remarkably reduced due to peeling at the interface between various plated joints such as gold plating and silver plating on semiconductor elements, lead frames, and inner leads and the cured product of the epoxy resin composition. It is. In addition, with the shift from leaded solder to lead-free solder, which originated from environmental problems, the temperature during the soldering process increased, and the solder resistance due to explosive stress generated by the evaporation of moisture contained in the semiconductor device However, it has become a bigger problem than before.

In order to improve reliability reduction due to solder processing, the amount of inorganic filler in the epoxy resin composition is increased to achieve low moisture absorption, high strength, and low thermal expansion of the cured product of the epoxy resin composition. In addition, there is a technique for improving the solder resistance of a semiconductor device and maintaining low viscosity and high fluidity at the time of molding an epoxy resin composition by using a low melt viscosity resin (for example, Patent Document 1). reference.). By using this method, the solder resistance of the cured product of the epoxy resin composition is considerably improved. However, as the filling ratio of the inorganic filler increases, the fluidity at the time of molding the epoxy resin composition is sacrificed, and the epoxy resin composition is cured. There was a drawback that the resin composition was not sufficiently filled in the package and voids were likely to occur.
In addition, as an effort to improve productivity, application of a release agent having a high release effect has been proposed (see, for example, Patent Document 2), but due to a decrease in resin components accompanying an increase in inorganic filler, There are problems with poor mold releasability, which is thought to be due to insufficient dispersibility of the mold release agent component, and poor appearance of resin trays and cured resin products, especially mold release agents with a high mold release effect. There was a defect that the surface of the cured product was easily raised, and the appearance of the cured resin product was significantly soiled when continuously produced. For this reason, even if the amount of the inorganic filler is increased, the fluidity and filling property during molding are not impaired, and the problems such as continuous moldability, appearance of the cured resin product, and mold contamination are dealt with. There has been a demand for further technology that satisfies the reliability of the apparatus.

JP-A 64-65116 JP 2002-80695 A

  The present invention has good fluidity, curability, releasability, and continuous moldability at the time of sealing molding even when the amount of inorganic filler is increased, and appearance stains and molds of resin cured products It is an object of the present invention to provide an epoxy resin composition for encapsulating a semiconductor that is less likely to cause dirt.

The present invention
[1] In the epoxy resin composition containing an epoxy resin (A), a phenol resin-based curing agent (B), an inorganic filler (C), a curing accelerator (D), and a release agent (E), the curing acceleration The agent (D) includes a curing accelerator (D1) having a cation part and a silicate anion part, and the release agent (E) is a pentaerythritol tetrafatty acid ester (E1) and / or dipentaerythritol hexafatty acid ester (E2). An epoxy resin composition for semiconductor encapsulation, comprising:
[2] In the epoxy resin composition for semiconductor encapsulation according to [1], the total amount of the pentaerythritol tetrafatty acid ester (E1) and the dipentaerythritol hexafatty acid ester (E2) is all epoxy. An epoxy resin composition for encapsulating a semiconductor, characterized in that the ratio is 0.01 wt% or more and 1 wt% or less in the resin composition;
[3] In the epoxy resin composition for semiconductor encapsulation according to [1] or [2], the cation part of the curing accelerator (D1) having the cation part and the silicate anion part is a phosphocation. An epoxy resin composition for encapsulating a semiconductor, characterized by comprising:

（ただし、上記一般式（１）において、Ｒ１、Ｒ２、Ｒ３及びＲ４は、それぞれ、芳香環又は複素環を有する有機基、或いは脂肪族基を表し、互いに同一であっても異なっていてもよい。Ｘ１は、基Ｙ１及びＹ２と結合する有機基である。Ｘ２は、基Ｙ３及びＹ４と結合する有機基である。Ｙ１及びＹ２はプロトン供与性基がプロトンを放出してなる基であり、同一分子内の基Ｙ１、及びＹ２が珪素原子と結合してキレート構造を形成するものである。Ｙ３及びＹ４はプロトン供与性基がプロトンを放出してなる基であり、同一分子内の基Ｙ３及びＹ４が珪素原子と結合してキレート構造を形成するものである。Ｘ１、及びＸ２は互いに同一であっても異なっていてもよく、Ｙ１、Ｙ２、Ｙ３、及びＹ４は互いに同一であっても異なっていてもよい。Ｚ１は芳香環又は複素環を有する有機基、或いは脂肪族基である。） [4] In the epoxy resin composition for semiconductor encapsulation according to any one of [1] to [3], the curing accelerator (D1) having the cation part and the silicate anion part is as follows. An epoxy resin composition for semiconductor encapsulation, which is a compound represented by the formula (1):

(In the general formula (1), R1, R2, R3 and R4 each represents an organic group having an aromatic ring or a heterocyclic ring, or an aliphatic group, and may be the same or different from each other. X1 is an organic group bonded to the groups Y1 and Y2, X2 is an organic group bonded to the groups Y3 and Y4, and Y1 and Y2 are groups formed by proton-donating groups releasing protons, Groups Y1 and Y2 in the same molecule bind to a silicon atom to form a chelate structure Y3 and Y4 are groups formed by proton donating groups releasing protons, and group Y3 in the same molecule And Y4 bind to a silicon atom to form a chelate structure, X1 and X2 may be the same or different, and Y1, Y2, Y3, and Y4 may be the same. Different Good .Z1 is an organic group, or an aliphatic group having an aromatic ring or a heterocyclic ring.)

[5] In the epoxy resin composition for semiconductor encapsulation according to any one of [1] to [4], the pentaerythritol tetrafatty acid ester (E1) is pentaerythritol and has 22 or more carbon atoms, 36 An epoxy resin composition for semiconductor encapsulation, which is a tetraester with the following saturated fatty acid,
[6] In the epoxy resin composition for semiconductor encapsulation according to any one of [1] to [4], the dipentaerythritol hexafatty acid ester (E2) is dipentaerythritol and 22 or more carbon atoms. An epoxy resin composition for semiconductor encapsulation, which is a hexaester with 36 or less saturated fatty acids,
[7] In the epoxy resin composition for semiconductor encapsulation according to any one of [1] to [6], the pentaerythritol tetrafatty acid ester (E1) and dipentaerythritol hexafatty acid ester (E2). An acid value of 10 mgKOH / g or more and 50 mgKOH / g or less, an epoxy resin composition for semiconductor encapsulation,
[8] A semiconductor device, wherein a semiconductor element is sealed with a cured product of the epoxy resin composition for sealing a semiconductor according to any one of [1] to [7],
It is.

  According to the present invention, even when the blending amount of the inorganic filler is increased, it has good fluidity, curability, releasability, and continuous moldability at the time of sealing molding of a semiconductor element, etc. An epoxy resin composition for encapsulating semiconductors that hardly causes appearance stains and mold stains is obtained.

The present invention includes an epoxy resin (A), a phenol resin-based curing agent (B), an inorganic filler (C), a curing accelerator (D) including a curing accelerator (D1) having a cation portion and a silicate anion portion, And a mold release agent (E) containing pentaerythritol tetrafatty acid ester (E1) and / or dipentaerythritol hexafatty acid ester (E2), thereby providing fluidity, curability, mold release, It is possible to obtain an epoxy resin composition for semiconductor encapsulation which is excellent in continuous moldability and hardly causes appearance stains and mold stains of the cured resin.
Hereinafter, the present invention will be described in detail.

  The epoxy resin (A) used in the present invention is a monomer, oligomer, or polymer in general having two or more epoxy groups in one molecule, and its molecular weight and molecular structure are not particularly limited. Resin, bisphenol type epoxy resin, stilbene type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, triphenolmethane type epoxy resin, alkyl-modified triphenolmethane type epoxy resin, triazine nucleus-containing epoxy resin, dicyclopentadiene modified Phenol type epoxy resin, phenol aralkyl type epoxy resin having phenylene skeleton, biphenylene skeleton, etc., sulfur atom containing type epoxy resin, naphthol type epoxy resin, naphthalene type epoxy resin, phenylene skeleton, Naphthol aralkyl type epoxy resins. Having Eniren skeleton like, which may be used in combination of two or more be used one kind alone. Among these, when solder resistance is particularly required, it is a crystalline solid at room temperature, but it becomes a liquid with a very low viscosity above the melting point, and can be highly filled with inorganic fillers. Biphenyl type epoxy resin, bisphenol type Crystalline epoxy resins such as epoxy resins and stilbene type epoxy resins are preferred. From the viewpoint of increasing the filling of the inorganic filler, it is desirable to use other epoxy resins having a viscosity as low as possible. In addition, when solder resistance, flexibility, and low moisture absorption are required, there should be no phenylene skeleton or biphenylene skeleton or the like having an epoxy group between the aromatic rings to which the epoxy group is bonded. Thus, aralkyl type epoxy resins such as phenol aralkyl type epoxy resins and naphthol aralkyl type epoxy resins exhibiting low hygroscopicity and low elasticity in a high temperature range during mounting are preferred. However, when an epoxy resin having low viscosity or flexibility as described above is used, the crosslink density of the cured resin becomes low, so that the releasability of the cured resin from the mold is lowered. There is also a point, and it may be necessary to improve releasability by using pentaerythritol tetrafatty acid ester (E1) and / or dipentaerythritol hexafatty acid ester (E2) described later.

  The blending ratio of the entire epoxy resin (A) used in the present invention is not particularly limited, but is preferably 2% by weight or more and 10% by weight or less in the total epoxy resin composition, and is 4% by weight or more, 8 More preferably, it is less than or equal to weight percent. When the blending ratio of the entire epoxy resin (A) is within the above range, there is little risk of causing a decrease in solder resistance, a decrease in fluidity, and the like.

  The phenol resin-based curing agent (B) used in the present invention is a monomer, oligomer or polymer in general having two or more phenolic hydroxyl groups in one molecule, and its molecular weight and molecular structure are not particularly limited. Phenol novolac resin, cresol novolac resin, dicyclopentadiene modified phenol resin, terpene modified phenol resin, triphenolmethane type resin, phenol aralkyl resin having phenylene skeleton, biphenylene skeleton, etc., sulfur atom containing type phenol resin, naphthol novolak resin, phenylene Examples thereof include naphthol aralkyl resins having a skeleton, a biphenylene skeleton, and the like, and these may be used alone or in combination of two or more. Among these, when solder resistance is particularly required, a low-viscosity resin is preferable in terms of being able to increase the filling of the inorganic filler, as well as the epoxy resin, and further, flexibility and low hygroscopicity are required. In this case, it is preferable to use a phenol aralkyl resin having a phenylene skeleton or a biphenylene skeleton. However, when a phenol resin-based curing agent having low viscosity or flexibility is used, the crosslink density of the cured resin becomes low, so that the releasability of the cured resin from the mold is lowered. In some cases, it is necessary to improve releasability by using pentaerythritol tetrafatty acid ester (E1) and / or dipentaerythritol hexafatty acid ester (E2) described later.

  The blending ratio of the phenol resin-based curing agent (B) used in the present invention is not particularly limited, but is preferably 2% by weight or more and 8% by weight or less in the total epoxy resin composition, and 3% by weight or more. 6% by weight or less is more preferable. When the blending ratio of the entire phenol resin-based curing agent (B) is within the above range, there is little risk of causing a decrease in solder resistance, a decrease in fluidity, and the like.

  As a compounding ratio of the epoxy resin (A) and the phenol resin curing agent (B) used in the present invention, the ratio of the number of epoxy groups (EP) of all epoxy resins and the number of phenolic hydroxyl groups (OH) of all phenol resin curing agents. (EP / OH) is preferably 0.7 or more and 1.3 or less. Within this range, it is possible to suppress a decrease in curability of the epoxy resin composition, a decrease in the glass transition temperature of the cured resin, a decrease in moisture resistance reliability, and the like.

  As an inorganic filler (C) used for this invention, what is generally used for the epoxy resin composition for semiconductor sealing can be used, Although it does not specifically limit, For example, fused silica, crystalline silica , Talc, alumina, silicon nitride, and the like, and most preferably used is spherical fused silica. These inorganic fillers may be used alone or in combination of two or more. The maximum particle size of the inorganic filler (C) is not particularly limited, but is 105 μm or less in consideration of prevention of defects such as wire flow caused by the coarse particles of the inorganic filler being sandwiched between the narrowed wires. It is preferable that it is 75 μm or less.

  Although content of the inorganic filler (C) used by this invention is not specifically limited, It is preferable that they are 80 weight% or more and 94 weight% or less in all the epoxy resin compositions, and 84 weight% or more and 92 weight%. % Or less is more preferable. Within this range, a decrease in solder resistance, a decrease in fluidity, and the like can be suppressed.

（ただし、上記一般式（１）において、Ｒ１、Ｒ２、Ｒ３及びＲ４は、それぞれ、芳香環又は複素環を有する有機基、或いは脂肪族基を表し、互いに同一であっても異なっていてもよい。Ｘ１は、基Ｙ１及びＹ２と結合する有機基である。Ｘ２は、基Ｙ３及びＹ４と結合する有機基である。Ｙ１及びＹ２はプロトン供与性基がプロトンを放出してなる基であり、同一分子内の基Ｙ１、及びＹ２が珪素原子と結合してキレート構造を形成するものである。Ｙ３及びＹ４はプロトン供与性基がプロトンを放出してなる基であり、同一分子内の基Ｙ３及びＹ４が珪素原子と結合してキレート構造を形成するものである。Ｘ１、及びＸ２は互いに同一であっても異なっていてもよく、Ｙ１、Ｙ２、Ｙ３、及びＹ４は互いに同一であっても異なっていてもよい。Ｚ１は芳香環又は複素環を有する有機基、或いは脂肪族基である。） The curing accelerator (D) used in the present invention is a curing accelerator (D1) having a cation part that can promote the curing reaction of the epoxy resin and a silicate anion part that suppresses the catalytic activity of the cation part that promotes the curing reaction. ) (Hereinafter, also simply referred to as “curing accelerator (D1)”). Since the curing accelerator (D1) does not easily start and accelerate the curing reaction at a temperature lower than the molding temperature of the epoxy resin (A) and the phenol resin-based curing agent (B), fluidity and storage stability. It is possible to impart excellent characteristics to the above. In addition, the curing accelerator (D1) is capable of easily imparting excellent curability in addition to the above characteristics because the cation portion is easily liberated in the molding temperature range to promote the curing reaction. It is. As a hardening accelerator (D1) which has a cation part and a silicate anion part, what a cation part contains a phosphorus cation is preferable, and the compound represented by following General formula (1) is more preferable.

(In the general formula (1), R1, R2, R3 and R4 each represents an organic group having an aromatic ring or a heterocyclic ring, or an aliphatic group, and may be the same or different from each other. X1 is an organic group bonded to the groups Y1 and Y2, X2 is an organic group bonded to the groups Y3 and Y4, and Y1 and Y2 are groups formed by proton-donating groups releasing protons, Groups Y1 and Y2 in the same molecule bind to a silicon atom to form a chelate structure Y3 and Y4 are groups formed by proton donating groups releasing protons, and group Y3 in the same molecule And Y4 bind to a silicon atom to form a chelate structure, X1 and X2 may be the same or different, and Y1, Y2, Y3, and Y4 may be the same. Different Good .Z1 is an organic group, or an aliphatic group having an aromatic ring or a heterocyclic ring.)

In the general formula (1), examples of the groups R1, R2, R3, and R4 include a phenyl group, a methylphenyl group, a methoxyphenyl group, a hydroxyphenyl group, a naphthyl group, a hydroxynaphthyl group, a benzyl group, a methyl group, and ethyl. Group, n-butyl group, n-octyl group, cyclohexyl group and the like, and among these, aromatic groups such as phenyl group, methylphenyl group, methoxyphenyl group, hydroxyphenyl group and hydroxynaphthyl group are more preferable.

In the general formula (1), the group X1 is an organic group bonded to the groups Y1 and Y2. Similarly, the group X2 is an organic group bonded to the groups Y3 and Y4. The groups Y1 and Y2 are groups formed by releasing protons from proton-donating groups, and the groups Y1 and Y2 in the same molecule are bonded to a silicon atom to form a chelate structure. Similarly, groups Y3 and Y4 are groups in which proton donating groups release protons, and groups Y3 and Y4 in the same molecule are bonded to silicon atoms to form a chelate structure. The groups X1 and X2 may be the same or different, and the groups Y1, Y2, Y3, and Y4 may be the same or different.
Such a group represented by Y1X1Y2 and Y3X2Y4 in the general formula (1) is composed of a group in which a proton donor releases two protons. Examples of the proton donor include: Catechol, pyrogallol, 1,2-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, 2,2'-biphenol, 2,2'-binaphthol, salicylic acid, 1-hydroxy-2-naphthoic acid, 3-hydroxy-2-naphtho Acid, chloranilic acid, tannic acid, 2-hydroxybenzyl alcohol, 1,2-cyclohexanediol, 1,2-propanediol, glycerin, etc., among these, catechol, 1,2-dihydroxynaphthalene, 2, 3-dihydroxynaphthalene is more preferred.

  Z1 in the general formula (1) represents an organic group or an aliphatic group having an aromatic ring or a heterocyclic ring, and specific examples thereof include a methyl group, an ethyl group, a propyl group, a butyl group, and a hexyl group. Reactions of aliphatic hydrocarbon groups such as octyl and octyl groups, aromatic hydrocarbon groups such as phenyl, benzyl, naphthyl and biphenyl, glycidyloxypropyl, mercaptopropyl, aminopropyl and vinyl Among them, a methyl group, an ethyl group, a phenyl group, a naphthyl group, and a biphenyl group are more preferable from the viewpoint of thermal stability.

  Although the compounding quantity of the hardening accelerator (D1) which has a cation part and a silicate anion part used by this invention is not specifically limited, 0.1 weight% or more and 1.5 weight% or less in all the epoxy resin compositions More preferably, it is 0.2 wt% or more and 1 wt% or less. Within the above range, the viscosity of the epoxy resin composition can be lowered, the fluidity can be increased, and the storage stability during storage can be improved.

  In the present invention, the curing accelerator other than the curing accelerator (D1) may be an epoxy group and a phenol as long as the effect of using the curing accelerator (D1) having a cation part and a silicate anion part is not impaired. As long as it promotes the reaction of the reactive hydroxyl group, it can be used in combination without any particular limitation, but the blending ratio of the curing accelerator (D1) having a cation silicate anion moiety is 50% by weight with respect to the total curing accelerator (D). The above is preferable. Examples of curing accelerators that can be used in combination include adducts of phosphine compounds and quinone compounds; diazabicycloalkenes such as 1,8-diazabicyclo (5,4,0) undecene-7 and derivatives thereof; tributylamine, benzyl Amine compounds such as dimethylamine; imidazole compounds such as 2-methylimidazole; organic phosphines such as triphenylphosphine and methyldiphenylphosphine; tetraphenylphosphonium tetraphenylborate, tetraphenylphosphonium tetrakis (benzoyloxy) borate, tetra Examples thereof include tetra-substituted phosphonium / tetra-substituted borates such as phenylphosphonium / tetrakis (naphthoyloxy) borate, and these may be used alone or in combination of two or more.

  In this invention, it is essential to contain pentaerythritol tetrafatty acid ester (E1) and / or dipentaerythritol hexafatty acid ester (E2) as a mold release agent (E).

  The pentaerythritol tetrafatty acid ester (E1) used in the present invention is a tetraester obtained from pentaerythritol and a saturated fatty acid, and has excellent release properties. Monoesters, diesters, and triesters reduce the moisture resistance of the cured product of the epoxy resin composition due to the effects of residual hydroxyl groups, and as a result, the solder heat resistance may be adversely affected. The tetra fatty acid ester (E1) is suitable as a mold release agent for use in a resin composition for semiconductor encapsulation because it does not cause the adverse effects described above. As the pentaerythritol tetrafatty acid ester (E1) used in the present invention, specifically, pentaerythritol tetracaproate, pentaerythritol tetracaprylate, pentaerythritol tetracaprate, pentaerythritol tetralaurate, pentaerythritol Tetramyristate, pentaerythritol tetrapalmitate, pentaerythritol tetrastearate, pentaerythritol tetraarachinate, pentaerythritol tetrabehenate, pentaerythritol tetralignoserate, pentaerythritol tetraserotinate, penta Erythritol tetramontanate, pentaerythritol Toramerishin acid ester and the like. Among these, a tetraester of pentaerythritol and a saturated fatty acid having 22 to 36 carbon atoms is preferable from the viewpoint of releasability and appearance of the cured resin. Furthermore, pentaerythritol tetramontanate is more preferable. In addition, the carbon number of the saturated fatty acid in the present invention refers to the sum of the carbon number of the alkyl group and the carboxyl group in the saturated fatty acid.

  The dipentaerythritol hexafatty acid ester (E2) used in the present invention is a hexaester obtained from dipentaerythritol and a saturated fatty acid, and has excellent release properties. If it is not a hexaester, the moisture resistance of the cured product of the epoxy resin composition is lowered by the influence of the remaining hydroxyl group, and as a result, it may adversely affect the solder heat resistance. The ester (E2) is suitable as a release agent for use in a resin composition for semiconductor encapsulation because it does not cause the adverse effects described above. Specific examples of the dipentaerythritol hexafatty acid ester (E2) used in the present invention include dipentaerythritol hexacaproate, dipentaerythritol hexacaprylate, dipentaerythritol hexacaprate, dipentaerythritol hexalaurin. Acid ester, dipentaerythritol hexamyristic acid ester, dipentaerythritol hexapalmitic acid ester, dipentaerythritol hexastearic acid ester, dipentaerythritol hexaaracinic acid ester, dipentaerythritol hexabehenic acid ester, dipentaerythritol hexalignoceric acid Esters, dipentaerythritol hexacerotate, dipentaerythritol hexamontanate Le, dipentaerythritol hexa Meri Shin acid ester and the like. Among these, a hexaester of dipentaerythritol and a saturated fatty acid having 22 to 36 carbon atoms is preferable from the viewpoint of releasability and appearance of the cured resin. Furthermore, dipentaerythritol hexamontanate is more preferable. In addition, the carbon number of the saturated fatty acid in the present invention refers to the sum of the carbon number of the alkyl group and the carboxyl group in the saturated fatty acid.

  The dropping point of the pentaerythritol tetrafatty acid ester (E1) and / or dipentaerythritol hexafatty acid ester (E2) used in the present invention is preferably 60 ° C. or higher and 100 ° C. or lower, more preferably 70 ° C. or higher and 90 ° C. or lower. It is. The dropping point can be measured by a method based on ASTM D127. Specifically, using a metal nipple, it is measured as the temperature at which molten wax first drops from the metal nipple. In the following examples, it can be measured by the same method. When the dropping point is within the above range, pentaerythritol tetrafatty acid ester (E1) and / or dipentaerythritol hexafatty acid ester (E2) is excellent in thermal stability, and during molding, pentaerythritol tetrafatty acid ester (E1) and / or Dipentaerythritol hexafatty acid ester (E2) is difficult to seize. Therefore, it is excellent in the mold release property of the resin cured material from a metal mold | die, and is excellent in continuous moldability. Furthermore, when the epoxy resin composition is cured within the above range, pentaerythritol tetrafatty acid ester (E1) and / or dipentaerythritol hexafatty acid ester (E2) are sufficiently melted. Thereby, pentaerythritol tetrafatty acid ester (E1) and / or dipentaerythritol hexafatty acid ester (E2) are dispersed substantially uniformly in the cured resin. Therefore, segregation of pentaerythritol tetrafatty acid ester (E1) and / or dipentaerythritol hexafatty acid ester (E2) on the surface of the cured resin product is suppressed, and deterioration of the appearance of the mold and the cured resin product can be reduced. it can.

  The acid value of the pentaerythritol tetrafatty acid ester (E1) and / or dipentaerythritol hexafatty acid ester (E2) used in the present invention is preferably 10 mgKOH / g or more and 50 mgKOH / g or less, more preferably 15 mgKOH / g or more, 40 mgKOH / g or less. The acid value affects the compatibility with the cured resin. The acid value can be measured by a method based on JIS K 3504. Specifically, it is measured as the number of milligrams of potassium hydroxide required to neutralize free fatty acids contained in 1 g of waxes. In the following examples, it can be measured by the same method. When the acid value is within the above range, pentaerythritol tetrafatty acid ester (E1) and / or dipentaerythritol hexafatty acid ester (E2) are in a compatible state with the epoxy resin matrix in the cured resin. As a result, the pentaerythritol tetrafatty acid ester (E1) and / or dipentaerythritol hexafatty acid ester (E2) and the epoxy resin matrix do not cause phase separation. Therefore, segregation of pentaerythritol tetrafatty acid ester (E1) and / or dipentaerythritol hexafatty acid ester (E2) on the surface of the cured resin product is suppressed, and deterioration of the appearance of the mold and the cured resin product can be reduced. it can. Furthermore, since pentaerythritol tetrafatty acid ester (E1) and / or dipentaerythritol hexafatty acid ester (E2) is present on the surface of the cured resin, the cured resin is excellent in releasability from the mold. On the other hand, if the compatibility with the epoxy resin matrix is too high, the pentaerythritol tetrafatty acid ester (E1) and / or the dipentaerythritol hexafatty acid ester (E2) cannot ooze out on the surface of the resin cured product, and sufficient separation is caused. In some cases, it is not possible to ensure the type.

  The amount of pentaerythritol tetrafatty acid ester (E1) and / or dipentaerythritol hexafatty acid ester (E2) used in the present invention is 0.01% by weight or more and 1% by weight or less in the epoxy resin composition. Is preferable, and more preferably 0.03% by weight or more and 0.5% by weight or less. When the blending amount is within the above range, the mold releasability of the cured resin from the mold is excellent. Furthermore, since the adhesiveness with the lead frame member is excellent, peeling between the lead frame member and the cured resin can be suppressed during the soldering process. In addition, it is possible to suppress deterioration of the mold and the appearance of the cured resin.

  The method for producing pentaerythritol tetrafatty acid ester (E1) and / or dipentaerythritol hexafatty acid ester (E2) used in the present invention is not particularly limited. For example, pentaerythritol and / or dipenta may be used as a raw material compound. It can be obtained by an ester reaction method using erythritol or a fatty acid according to a known method. In addition, pentaerythritol tetrafatty acid ester (E1) and / or dipentaerythritol hexafatty acid ester (E2) used in the present invention is commercially available, such as Clariant Japan Co., Ltd., Recommont ET141, etc. In addition, a pulverizer such as a rotating disk mill (pin mill), a screen mill (hammer mill), a centrifugal mill (turbo mill), a jet mill or the like can be used after pulverization and particle size adjustment.

  Other mold release agents can be used in combination as long as the effects of using the pentaerythritol tetrafatty acid ester (E1) and / or dipentaerythritol hexafatty acid ester (E2) used in the present invention are not impaired. Examples of release agents that can be used in combination include natural waxes such as carnauba wax, and metal salts of higher fatty acids such as zinc stearate.

  The present invention relates to a curing accelerator (D1) having a cation moiety that can accelerate the curing reaction of an epoxy resin and a silicate anion moiety that suppresses the catalytic activity of the cation moiety that accelerates the curing reaction, and a pentaerythritol tetrafatty acid ester ( E1) and / or dipentaerythritol hexafatty acid ester (E2) is used in combination to express the synergistic effect. By using these two types in combination, even when the amount of the inorganic filler is increased, an ideal release behavior is exhibited without impairing the dispersibility of the release agent.

  The epoxy resin composition for semiconductor encapsulation of the present invention comprises an epoxy resin (A), a phenol resin-based curing agent (B), an inorganic filler (C), and a curing accelerator (D1) having a cation portion and a silicate anion portion. And a mold release agent (E) containing pentaerythritol tetrafatty acid ester (E1) and / or dipentaerythritol hexafatty acid ester (E2), and if necessary, an aminosilane. , Epoxy silane, mercapto silane, alkyl silane, ureido silane, acrylic silane, etc. coupling agents; hydrotalcites, ion trapping agents such as hydrous oxides of elements selected from magnesium, aluminum, bismuth, titanium, zirconium; silicone Low stress additives such as oil and rubber; thiazoline, tria Additives such as brominated epoxy resin, antimony trioxide, aluminum hydroxide, magnesium hydroxide, zinc borate, zinc molybdate, phosphazene and other flame retardants There is no problem.

  The epoxy resin composition for semiconductor encapsulation of the present invention is, for example, a material in which raw materials are sufficiently uniformly mixed using a mixer or the like, and then melt-kneaded with a kneader such as a hot roll, a kneader or an extruder. Those that have been appropriately adjusted in dispersity, fluidity, and the like can be used as needed, such as those pulverized after cooling.

  Conventional molding such as transfer molding, compression molding, injection molding, etc., is used to manufacture semiconductor devices by sealing various electronic components such as semiconductor elements using the epoxy resin composition for semiconductor sealing of the present invention. It may be cured by the method.

The semiconductor element that performs sealing in the present invention is not particularly limited, and examples thereof include an integrated circuit, a large-scale integrated circuit, a transistor, a thyristor, a diode, and a solid-state imaging element.
The form of the semiconductor device of the present invention is not particularly limited. For example, the dual in-line package (DIP), the plastic lead chip carrier (PLCC), the quad flat package (QFP), the small outline, and the like. Package (SOP), Small Outline J Lead Package (SOJ), Thin Small Outline Package (TSOP), Thin Quad Flat Package (TQFP), Tape Carrier Package (TCP), Ball Grid Examples include an array (BGA), a chip size package (CSP), and the like.
A semiconductor device sealed by a molding method such as the above transfer mold is completely cured at a temperature of about 80 ° C. to 200 ° C. for about 10 minutes to 10 hours, and then mounted on an electronic device or the like. Is done.

  FIG. 1 is a view showing a cross-sectional structure of an example of a semiconductor device using the epoxy resin composition according to the present invention. The semiconductor element 1 is fixed on the die pad 3 via the die bond material cured body 2. The electrode pad of the semiconductor element 1 and the lead frame 5 are connected by a gold wire 4. The semiconductor element 1 is sealed with a cured body 6 of a sealing resin composition.

Examples of the present invention are shown below, but the present invention is not limited thereto. The blending ratio is parts by weight.
In addition, it shows below about the content of the hardening accelerator and mold release agent which were used by the Example and the comparative example.

Curing accelerator 1: Compound represented by the following chemical formula (2)

Curing accelerator 2: Compound represented by the following chemical formula (3)

Curing accelerator 3: Compound represented by the following chemical formula (4)

Curing accelerator 4: Compound represented by the following chemical formula (5)

Curing accelerator 5: Compound represented by the following chemical formula (6)

Curing accelerator 6: Compound represented by the following chemical formula (7)

Curing accelerator 7: Compound represented by the following chemical formula (8)

Release agent 1: Pentaerythritol tetramontanate (manufactured by Clariant Japan Co., Ltd., Recommont ET141, dropping point 76 ° C., acid value 25 mgKOH / g)
Release agent 2: pentaerythritol tetrabehenate (melting behenic acid, pentaerythritol (molar ratio of pentaerythritol and behenic acid = 1: 4.2)) and tin compound (total amount of pentaerythritol and behenic acid 100 weight) The mixture was stirred at 200 ° C. under a nitrogen atmosphere and distilled in reaction water until the acid value decreased to less than 35. After completion of the reaction, the reaction was performed using an aqueous potassium hydroxide solution. The free fatty acid in the mixture was neutralized, and then washed with warm water, dehydrated, filtered, and pulverized (drop point 71 ° C., acid value 30 mgKOH / g).
Release agent 3: Dipentaerythritol hexabehenate (Riken Vitamin Co., Ltd., Riquester EW-861, dropping point 80 ° C., acid value 20 mgKOH / g)
Release agent 4: Dipentaerythritol hexamontanate (melting montanic acid, dipentaerythritol (molar ratio of dipentaerythritol and montanic acid = 1: 6.3)) and 70% methanesulfonic acid (dipentaerythritol) And 0.2% by weight relative to 100% by weight of the total amount of montanic acid), and stirred at 220 ° C. in a nitrogen atmosphere under distilling of the reaction water until the acid value dropped to less than 30. The free fatty acid in the reaction mixture was neutralized with an aqueous potassium hydroxide solution, followed by washing with warm water, dehydration, filtration, and pulverization (drop point 84 ° C., acid value 25 mgKOH / g).
Release agent 5: Pentaerythritol distearate (Riken Vitamin Co., Ltd., Riquemar HT-10, dropping point 52 ° C., acid value 3 mg KOH / g)
Release agent 6: Carnauba wax (manufactured by Nikko Fine Products Co., Ltd., trade name Nikko Carnauba, drop point 83 ° C., acid value 5 mgKOH / g)

Here, as an example, a method for synthesizing the curing accelerator 1 will be described, but the present invention is not limited thereto.
In a flask containing 1800 g of methanol, 249.5 g of phenyltrimethoxysilane and 384.0 g of 2,3-dihydroxynaphthalene were added and dissolved, and then 231.5 g of 28% sodium methoxide-methanol solution was added dropwise with stirring at room temperature. Furthermore, when a solution prepared by dissolving 503.0 g of tetraphenylphosphonium bromide prepared in advance in 600 g of methanol was added dropwise with stirring at room temperature, crystals were deposited. The precipitated crystals were filtered, washed with water, and vacuum-dried to obtain a pinkish white crystal curing accelerator 1.

Example 1
Epoxy resin 1: phenol aralkyl epoxy resin having a biphenylene skeleton represented by the following formula (9) (manufactured by Nippon Kayaku Co., Ltd., trade name: NC3000P, softening point: 58 ° C., epoxy equivalent: 273, in the following formula (9) The average value of n is 1.8.) 6.19 parts by weight

Phenol resin-based curing agent 1: phenol aralkyl resin having a biphenylene skeleton represented by the following formula (10) (Madewa Kasei Co., Ltd., trade name MEH-7851SS, softening point 67 ° C., hydroxyl group equivalent 204. Formula (10) The average value of n in) 1.5.)
4.61 parts by weight

Fused spherical silica 1: (average particle size 20 μm, maximum particle size 75 μm, specific surface area 3.6 m ² / g) 78.00 parts by weight Fused spherical silica 2: (average particle size 0.5 μm, maximum particle size 10 μm, specific surface area) 5.9 m ² / g) 10.00 parts by weight Curing accelerator 1 0.50 parts by weight Release agent 1 0.10 parts by weight Coupling agent: γ-glycidoxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.) , Trade name KBM-403) 0.30 parts by weight Carbon black: (Mitsubishi Chemical Co., Ltd., trade name MA-600) After mixing 0.30 parts by weight with a mixer, at 95 ° C. using a hot roll. The mixture was kneaded for 8 minutes, further cooled and pulverized to obtain an epoxy resin composition. The obtained epoxy resin composition was evaluated by the following methods. The results are shown in Table 1.

Evaluation method: Spiral flow: Using a low-pressure transfer molding machine (KTS-15, manufactured by Kotaki Seiki Co., Ltd.), a mold for spiral flow measurement according to EMMI-1-66, a mold temperature of 175 ° C. and an injection pressure of 6. The epoxy resin composition was injected under the conditions of 9 MPa and holding pressure time of 120 seconds, and the flow length was measured. The unit is cm. Spiral flow is a parameter of fluidity, and a larger value indicates better fluidity.

  Metal wire flow rate: Using a low-pressure transfer automatic molding machine (GP-ELF, manufactured by Daiichi Seiko Co., Ltd.), with a mold temperature of 175 ° C., an injection pressure of 9.8 MPa, and a curing time of 70 seconds, silicon is formed with an epoxy resin composition. Chips and the like are sealed and molded, and 160-pin LQFP (preprating frame: nickel / palladium alloy gold-plated, package outer dimensions: 24 mm × 24 mm × 1.4 mm thickness, pad size: 8.5 mm × 8.5 mm, A chip size of 7.4 mm × 7.4 mm × 350 μm thickness) was obtained. The obtained 160-pin LQFP package was observed with a soft X-ray fluoroscope (PRO-TEST100, manufactured by Softex Corporation), and the flow rate of the gold wire was determined as the ratio of (flow rate) / (gold wire length). . The criterion was ○ for less than 5% and x for 5% or more.

  Curability (curing torque ratio): Using a curast meter (manufactured by Orientec Co., Ltd., JSR curast meter IVPS type) under conditions of a die diameter of 35 mm, an amplitude angle of 1 °, and a mold temperature of 175 ° C. The curing behavior of the resin composition charged into the inside was measured by a change in torque. From the torque values 60 seconds and 300 seconds after the start of measurement, the curing torque ratio: (torque after 60 seconds) / (torque after 300 seconds) was calculated. The curing torque ratio in the curast meter is a parameter representing curability, and the larger the curing torque ratio, the better the curability. Judgment criteria set 0.7 or more as ◯ and less than 0.7 as x.

  Continuous moldability: Silicon chip using epoxy resin composition under conditions of mold temperature of 175 ° C., injection pressure of 9.8 MPa, curing time of 70 seconds using low pressure transfer automatic molding machine (Daiichi Seiko, GP-ELF) 80 pin QFP (Pre-plating frame: nickel / palladium alloy gold-plated, package outer dimensions: 14 mm x 20 mm x 2 mm thickness, pad size: 6.5 mm x 6.5 mm, chip size 6.0 mm Molding to obtain (× 6.0 mm × 350 μm thickness) was continuously performed up to 800 shots. Judgment criteria were ◎ for those that could be continuously molded up to 800 shots without any problems such as unfilling or mold release failure, ◯ for those that could be continuously molded up to 500 shots, and × otherwise.

  Package appearance and mold stain resistance: In the evaluation of the above-mentioned continuous moldability, the package and the mold after 500 shots were visually evaluated for stain. Judgment criteria for package appearance and mold dirtiness are indicated by x for those in which dirt has occurred up to 500 shots, ◯ for those in which dirt has not been stained up to 500 shots, and ◎ for those not dirty up to 800 shots. Further, in the above-mentioned continuous formability, those that could not be formed without any problem up to 800 shots were judged based on the package appearance and mold contamination status when the continuous forming was abandoned.

  Solder resistance: The package formed in the above-described evaluation of continuous formability is post-cured at 175 ° C. for 8 hours, and the resulting package is humidified at 85 ° C. and 60% relative humidity for 168 hours, followed by IR reflow treatment at 260 ° C. Did. For 20 packages, the adhesion state of the interface between the semiconductor element and the cured product of the epoxy resin composition was observed with an ultrasonic flaw detector, and the peeling occurrence rate [(number of peeling occurrence packages) / (total number of packages) × 100] Calculated. The criteria for determining solder resistance were ◯ when no peeling occurred, Δ when the peeling rate was less than 20%, and x when the peeling rate was 20% or more.

Examples 2-13, Comparative Examples 1-7
According to the composition of Table 1, Table 2, and Table 3, an epoxy resin composition was obtained in the same manner as in Example 1 and evaluated in the same manner as in Example 1. The results are shown in Table 1, Table 2, and Table 3.
The raw materials used other than Example 1 are shown below.
Epoxy resin 2: Biphenyl type epoxy resin represented by the following formula (11) (manufactured by Japan Epoxy Resin Co., Ltd., trade name YX-4000, epoxy equivalent 190, melting point 105 ° C.)

Phenol resin curing agent 2: Phenol aralkyl resin represented by the following formula (12) (Mitsui Chemicals, trade name: XLC-LL, hydroxyl group equivalent: 165, softening point: 79 ° C.)

Examples 1 to 13 include a curing accelerator (D1) having a cation part and a silicate anion part, pentaerythritol tetrafatty acid ester (E1) and / or dipentaerythritol hexafatty acid ester (E2), and epoxy. Type and blending ratio of resin (A) and phenol resin-based curing agent (B), blending ratio of inorganic filler (C), type and blending ratio of curing accelerator (D1) having a cation part and a silicate anion part, Including any of the different types and blending ratios of pentaerythritol tetrafatty acid ester (E1) and / or dipentaerythritol hexafatty acid ester (E2), both have good fluidity (spiral flow), gold wire flow Rate, curability, mold release, continuous moldability, package appearance, mold stain resistance and solder resistance It was the result of having.
On the other hand, in Comparative Examples 1, 2, and 6 that did not use pentaerythritol tetrafatty acid ester (E1) and / or dipentaerythritol hexafatty acid ester (E2), the continuous moldability deteriorated, the package appearance, mold soiling, The solder resistance was also inferior.
Further, in Comparative Examples 3, 4, 5, and 7 in which the curing accelerator (D1) having a cation portion and a silicate anion portion is not used, the deformation rate of the gold wire deteriorates due to the decrease in the fluidity of the resin composition. In addition, continuous formability, package appearance, mold stain resistance, and solder resistance were poor. Further, depending on the type and amount of the curing accelerator, the curability was inferior.
From the above, the epoxy resin composition for semiconductor encapsulation of the present invention has fluidity and curability at the time of molding even though the blending amount of the inorganic filler is as high as 88% by weight and 90% by weight of the whole resin composition. It has been found that a semiconductor device package having an excellent balance of releasability, continuous formability, package appearance, mold contamination and solder resistance can be provided.

  The epoxy resin composition for semiconductor encapsulation of the present invention has good fluidity, curability, releasability, and continuous moldability at the time of molding even when the blending amount of the inorganic filler is increased, and the resin is cured. It is possible to obtain an epoxy resin composition that hardly causes appearance stains or mold stains on the product. Therefore, the amount of the inorganic filler can be increased by using it in combination with an epoxy resin and / or a phenol resin curing agent having low viscosity and flexibility, thereby enabling high-temperature solder processing corresponding to lead-free solder. In addition, since an epoxy resin composition for semiconductor encapsulation having good solder resistance that does not generate cracks can be obtained, it can be suitably used for a semiconductor device that performs surface mounting using lead-free solder.

It is the figure which showed the cross-section about an example of the semiconductor device using the epoxy resin composition which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Semiconductor element 2 Die-bonding material hardening body 3 Die pad 4 Gold wire 5 Lead frame 6 Hardening body of resin composition for sealing

Claims (3)

In the epoxy resin composition for semiconductor encapsulation containing an epoxy resin (A), a phenol resin-based curing agent (B), an inorganic filler (C), a curing accelerator (D), and a release agent (E), the curing The accelerator (D) includes a curing accelerator (D1) having a cation part and a silicate anion part, and the curing accelerator (D1) is any compound represented by the following chemical formulas (2) to (5) There, the saw including a release agent (E) is pentaerythritol tetra fatty acid ester (E1) and / or dipentaerythritol hexa fatty acid ester (E2), the pentaerythritol tetra fatty acid ester (E1) is pentaerythritol and 22 carbon atoms These are tetraesters with 36 or less saturated fatty acids, and the dipentaerythritol hexafatty acid ester (E2) is dipentaerythritol. And pentaerythritol tetrafatty acid ester (E1) and dipentaerythritol hexafatty acid ester (E2) having an acid value of 10 mgKOH / g or more and 50 mgKOH / g. epoxy resin composition for semiconductor encapsulation which is characterized in that less.

  2. The epoxy resin composition for semiconductor encapsulation according to claim 1, wherein the total amount of the pentaerythritol tetrafatty acid ester (E1) and the dipentaerythritol hexafatty acid ester (E2) is 0 in the total epoxy resin composition. An epoxy resin composition for encapsulating a semiconductor, characterized by having a ratio of 0.01% by weight or more and 1% by weight or less. Wherein a semiconductor element is sealed with a cured product of claim 1 or the semiconductor encapsulating epoxy resin composition according to claim 2.

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