JP2867471B2 - Resin composition - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a resin composition used for sealing a semiconductor device. More specifically, it is a resin composition that prevents cracks in a sealing resin during a soldering process when mounting a resin-sealed semiconductor device, and has a high reliability particularly excellent in moisture resistance and moldability. And a resin composition of

<Related Art> In recent years, in the field of semiconductor integrated circuits, high integration,
At the same time as the development of high reliability technology, automation of the process of assembling semiconductor devices onto wiring boards is being promoted. For example, when mounting a flat-package type semiconductor device on a circuit board, soldering has conventionally been performed for each lead pin, but recently, the entire semiconductor device is immersed in a solder bath heated to 250 ° C or higher. The mounting method is adopted. For this reason, a conventional package sealed with a sealing resin has a problem that cracks occur in the resin portion at the time of soldering, and the reliability is reduced and the package cannot be used as a product.

As a method for sealing a semiconductor, a method in which a semiconductor element is set in a mold and sealed by a transfer molding method or the like using a composition obtained by adding a curing agent and a filler to an epoxy resin is generally performed. Have been done.

The characteristics required for these semiconductor sealing resins include:
There are solder heat resistance, reliability, moldability, and the like. Reliability includes moisture resistance and the like, and moldability includes release properties, flow marks, and the like. Moisture resistance here means high temperature,
If the resin-encapsulated semiconductor is left in a high-humidity environment, the intrusion of moisture through the interface between the encapsulation resin and the encapsulation resin and the lead frame prevents the semiconductor from being damaged, In recent years, as the degree of integration of semiconductors has been improved, higher moisture resistance has been required.

In view of the above situation, as a conventional method for improving the solder crack resistance of the sealing resin, for example, a method using a biphenyl type epoxy resin (Japanese Patent Application Laid-Open No. 63-251419) has been proposed. I have.

In order to improve the moisture resistance of the sealing resin, a silane coupling agent is usually added. Specifically, a method of adding epoxysilane to a normal epoxy resin (Japanese Patent Publication No. Sho 62-17640) JP-A-62-223219 and JP-A-57-223219.
No. 155753).

<Problems to be Solved by the Invention> However, in the method using a biphenyl-type epoxy resin, although the solder crack resistance of the sealing resin is improved, there are problems such as a decrease in moisture resistance, releasability and flow marks. It was not practical.

In addition, in the method of adding a vinyl silane coupling agent or an epoxy silane coupling agent, the improvement of moisture resistance by these additions has not been sufficient yet, and it has been difficult to use as a product.

Accordingly, an object of the present invention is to solve the above-mentioned problems of the epoxy resin composition for semiconductor encapsulation, and to provide an epoxy resin excellent in reliability such as solder heat resistance and moisture resistance, moldability and moldability such as flow mark. An object of the present invention is to provide a composition to enable a resin-sealed semiconductor for surface mounting.

<Means for Solving the Problems> The present inventors have proposed a biphenyl type epoxy resin,
By adding a silane coupling agent having a vinyl group, the above-mentioned problems were achieved, and it was found that an epoxy resin composition meeting the above-mentioned object was obtained.

That is, the present invention provides a resin composition comprising an epoxy resin (A), a curing agent (B), a filler (C), and a silane coupling agent (D), wherein the epoxy resin (A) has the following formula (I) ) (However, R ^{1 to} R ^{8 each} represent a hydrogen atom, a lower alkyl group having 1 to 4 carbon atoms or a halogen atom). The epoxy resin (a) having a skeleton represented by the following formula: The present invention provides a resin composition, wherein the silane coupling agent (D) is a silane compound containing a vinyl group.

 Hereinafter, the configuration of the present invention will be described in detail.

The epoxy resin (A) in the present invention has the following formula (I) (However, R ^{1 to} R ⁸ represent a hydrogen atom, a lower alkyl group having 1 to 4 carbon atoms or a halogen atom.) A biphenyl type epoxy resin (a) having a skeleton represented by the following formula: It is important to.

When the epoxy resin (a) is not contained, the effect of preventing the occurrence of cracks in the soldering step cannot be expected.

In the above formula (I), preferred specific examples of R ^{1 to} R ⁸ include a hydrogen atom, a methyl group, an ethyl group, a propyl group, i
-Propyl group, n-butyl group, sec-butyl group, tert-
Examples include a butyl group, a chlorine atom and a bromine atom.

Preferred specific examples of the epoxy resin (a) in the present invention include 4,4'-bis (2,3-epoxypropoxy) biphenyl and 4,4'-bis (2,3-epoxypropoxy)-
3,3 ', 5,5'-tetramethylbiphenyl, 4,4'-bis (2,3-epoxypropoxy) -3,3', 5,5'-tetramethyl-2-chlorobiphenyl, 4,4 '-Bis (2,3-epoxypropoxy) -3,3,5,5'-tetramethyl-2-promobiphenyl, 4,4'-bis (2,3-epoxypropoxy) -3,3', 5 5,5'-tetraethylbiphenyl and 4,
4'-bis (2,3-epoxypropoxy) -3,3 ', 5,5'
-Tetrabutylbiphenyl and the like.

The epoxy resin (A) in the present invention can contain, in addition to the above epoxy resin (a), another epoxy resin other than the epoxy resin (a). As other epoxy resins that can be used in combination, for example, cresol novolak type epoxy resin, phenol novolak type epoxy resin, novolak type epoxy resin represented by the following formula (II), Various novolak type epoxy resins synthesized from bisphenol A or resorcinol, bisphenol type epoxy resins, linear aliphatic epoxy resins, alicyclic epoxy resins,
Examples include a heterocyclic epoxy resin and a halogenated epoxy resin.

The proportion of the epoxy resin (a) contained in the epoxy resin (A) is not particularly limited, and the effect of the present invention is exhibited if the epoxy resin (a) is contained as an essential component. In order to exert the effect, it is necessary that the epoxy resin (a) is usually contained in the epoxy resin (A) in an amount of 30% by weight or more, preferably 50% by weight or more.

In the resin composition of the present invention, the amount of the epoxy resin (A) is usually 3 to 30% by weight, preferably 5 to 25% by weight.

The curing agent (B) in the present invention is not particularly limited as long as it reacts with the epoxy resin (A) and cures. Specific examples thereof include, for example, phenol novolak resin, cresol novolak resin, and the following formula (III)
Novolak resin represented by Various novolak resins synthesized from bisphenol A and resorcinol, various polyhydric phenol compounds, acid anhydrides such as maleic anhydride, phthalic anhydride and pyromellitic anhydride, and aromatics such as metaphenylenediamine, diaminodiphenylmethane, diaminodiphenylsulfone Amines and the like.

Above all, for encapsulation of semiconductor devices, novolak resins such as phenol novolak and cresol novolak are preferably used from the viewpoint of heat resistance, moisture resistance and storage stability. Can also.

In the resin composition of the present invention, the amount of the curing agent (B) is usually 1 to 20% by weight, preferably 2 to 15% by weight.
Furthermore, the mixing ratio of the epoxy resin (A) and the curing agent (B) is such that the chemical equivalent ratio of (B) to (A) is in the range of 0.5 to 1.6, particularly 0.8 to 1.3 from the viewpoint of mechanical properties and moisture resistance. Is preferred.

In the present invention, a curing catalyst may be used to accelerate the curing reaction between the epoxy resin (A) and the curing agent (B). The curing catalyst is not particularly limited as long as it promotes the curing reaction. For example, 2-methylimidazole, 2,4-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methyl Imidazole compounds such as imidazole and 2-heptadecyl imidazole, triethylamine, benzyldimethylamine, α-methylbenzyldimethylamine,
Tertiary amine compounds such as-(dimethylaminomethyl) phenol, 2,4,6-tris (dimethylaminomethyl) phenol, 1,8-diazabicyclo (5,4,0) undecene-7, zirconium tetramethoxide, zirconium Tetrapropoxide, tetrakis (acetylacetonato)
Organometallic compounds such as zirconium, tri (acetonatonat) aluminum and triphenylphosphine,
Organic phosphine compounds such as trimethylphosphine, triethylphosphine, tributylphosphine, tri (p-methylphenyl) phosphine, and tri (nonylphenyl) phosphine are exemplified. Above all, from the point of moisture resistance,
Organic phosphine compounds are preferred, and triphenylphosphine is particularly preferably used.

These curing catalysts may be used in combination of two or more depending on the use, and the addition amount thereof is preferably in the range of 0.1 to 10 parts by weight based on 100 parts by weight of the epoxy resin (A).

As the filler (C) in the present invention, fused silica,
Examples include crystalline silica, calcium carbonate, magnesium carbonate, alumina, magnesia, clay, talc, calcium silicate, titanium oxide, asbecit, and glass fiber. Among them, fused silica is preferably used because it has a large effect of lowering the linear expansion coefficient and is effective in reducing stress. Furthermore, the ratio of the filler (C) is 75 to 90% by weight of the whole, and the filler (C) is 90 to 40% by weight of the crushed fused silica (C ') having an average particle size of 12 μm or less, and the average particle size. 40μ
It is preferable from the viewpoint of solder heat resistance that fused silica composed of 10 to 60% by weight of spherical fused silica (C ″) of m or less is included.

Here, the average particle diameter means a particle diameter (median diameter) at which the cumulative weight becomes 50%.

The silane coupling agent (D) in the present invention is a silane compound containing a vinyl group. Specific examples of these silane coupling agents (D) include the following formula (IV):
(V) and (VI).

(R ¹ , R ² , and R ³ are a hydrogen atom, a monovalent hydrocarbon group having 1 to 20 carbon atoms, R ⁴ is a divalent hydrocarbon group having 0 to 20 carbon atoms, and R ⁵ is a carbon atom having 1 to 20 carbon atoms. And n represents an integer of 1 to 3. Among them, vinyltrimethoxysilane and γ-methacryloxypropyltriethoxysilane are preferably used from the viewpoint of moisture resistance reliability.

The amount of the silane coupling agent (D) to be added is usually 0.1 to 5 parts by weight, preferably 0.2 to 3 parts by weight, particularly preferably 0.3 to 1.5 parts by weight, based on 100 parts by weight of the filler. Depending on the application, other silane coupling agents such as epoxy silane, mercapto silane, amino silane, etc. can be used in combination.

In the present invention, it is preferable from the standpoint of reliability that the filler (C) is subjected to a surface treatment in advance with a silane coupling agent (D) and, if necessary, another silane coupling agent such as epoxysilane or mercaptosilane.

In the present invention, a silicone polymer (E) can be further added in order to reduce stress and improve reliability of the composition. The silicone polymer (E) has an organopolysiloxane structure, and specific examples include those represented by the following formula (VI).

(R _{1 to} R ₅ are one or more functional groups selected from hydrogen, an alkyl group having 1 to 20 carbon atoms, a phenyl group and a vinyl group, X,
Y is an alkyl group having 1 to 20 carbon atoms, a phenyl group, a vinyl group, a hydroxyl group, an amino group, an epoxy group, a carboxyl group,
It is a functional group having at least one group and / or atom selected from a mercapto group, a polyoxyalkylene group, an alkoxy group and a fluorine atom, and Y may be hydrogen. M represents an integer of 1 or more, and n represents an integer of 0 or more. The addition amount of the silicone polymer (E) is usually 0.01 to 5% by weight, preferably 0.1 to 5% in terms of low stress and reliability.
A preferred range is 3% by weight, especially 0.3 to 2% by weight.

The resin composition of the present invention further includes a halogen compound such as a halogenated epoxy resin, a flame retardant such as a phosphorus compound,
Flame retardant aids such as antimony trioxide, carbon black,
Colorants such as iron oxide, silicone rubber, styrene block copolymer, olefin copolymer, elastomer such as modified nitrile rubber, modified polybutadiene rubber, thermoplastic resin such as polyethylene, coupling agent such as titanate coupling agent A releasing agent such as a long-chain fatty acid, a metal salt of a long-chain fatty acid, an ester of a long-chain fatty acid, an amide of a long-chain fatty acid, paraffin wax and a crosslinking agent such as an organic peroxide can be optionally added.

The epoxy resin composition of the present invention is produced by a known kneading method such as a Banbury mixer, a kneader, a roll, a single-screw or twin-screw extruder and a co-kneader, preferably by melt-kneading.

<Example> Hereinafter, the present invention will be specifically described with reference to examples.

For the formulation shown in Table 1, the fused silica shown in Table 2, the silane coupling agent shown in Table 3, and the modified silicone oil shown in Table 4 were blended at the composition ratio shown in Table 5, respectively. This was dry-blended by a mixer.
Next, the mixture was heated and kneaded for 5 minutes using a mixing roll having a roll surface temperature of 90 ° C., and then cooled and pulverized to produce an epoxy-containing composition.

Using this composition, low pressure transfer molding
Post-curing was performed at 175 ° C for 4 minutes for 5 hours. After the post cure, the physical properties of each composition were measured by the following physical property measuring methods.

Solder heat resistance: After humidifying 20 pieces of 64 pins at 85 ° C / 85% RH for 50 hours, 2
It was immersed in a solder bath heated to 60 ° C. for 10 seconds, and the ratio of the number of QFPs in which cracks did not occur was determined.

Reliability: USPCBT was performed using a 16-pin DIP at 120 ° C / 85% RH and a bias voltage of 15V, and the time required for the cumulative failure rate to reach 50% was determined.

The moldability was evaluated by the following method using the resin composition produced by the above method.

Measurement of releasability: Molding was performed by a low-pressure transfer molding method using a mold for measuring releasability under the conditions of 175 ° C. × 120 seconds, and the release force was measured with a push-pull gauge.

◎: 5kgf or less ○: 10kgf or less △: 20kgf or less ×: 30kgf or less Flow mark: Diameter 10 by low pressure transfer molding method
A cm disk was molded under the conditions of 175 ° C. × 120 seconds, and flow marks were observed.

:: 100 shots or more without flow mark ○: 50 shots or more without flow mark △: 10 shots or more without flow mark ×: 5 shots or more without flow mark The above evaluation results are summarized in Table 5.

As shown in Table 5, the resin composition of the present invention (Examples 1 to 4) is excellent in solder heat resistance, reliability, and flow mark. On the other hand, Comparative Example 1 containing no biphenyl type epoxy resin has extremely poor solder heat resistance, and Comparative Example 2 not using the vinyl silane coupling agent of the present invention is inferior in solder heat resistance, reliability and releasability. Then, a flow mark also appears.

The resin compositions of the present invention containing 75 to 90% by weight of a specific fused silica (Examples 7 to 10) are excellent in reliability and further improved in solder heat resistance.

As shown in Table 5, the epoxy resin composition of the present invention further containing a silicone polymer (Example 11)
Nos. 14 to 14) have excellent solder heat resistance and further improved reliability and releasability.

<Effect of the Invention> The resin composition of the present invention is excellent in solder heat resistance, reliability and moldability, and has ideal performance for semiconductor encapsulation.

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁶ identification code FI C08K 3:00 5:54) (56) References JP-A-63-251419 (JP, A) JP-A-62-223219 (JP) , A) JP-A-63-99221 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C08L 63/00-63/10 C08K 5/54 C08K 13/02 H01L 23/29

Claims (3)

(57) [Claims] 1. A resin composition comprising an epoxy resin (A), a curing agent (B), a filler (C) and a silane coupling agent (D), wherein the epoxy resin (A) has the following formula (I) ) Wherein R ^{1 to} R ⁸ represent a hydrogen atom, a lower alkyl group having 1 to 4 carbon atoms or a halogen atom. The epoxy resin (a) having a skeleton represented by the following formula: A resin composition, wherein the ring agent (D) is a vinyl silane compound containing a vinyl group. 2. The resin composition according to claim 1, further comprising a silicone polymer (E) in addition to the components (A) to (D). 3. A semiconductor device sealed with the resin composition according to claim 1.