JPH0459862A - Epoxy resin composition for sealing semiconductor - Google Patents

Abstract

PURPOSE:To provide an epoxy resin composition having excellent soldering heat resistance, moisture resistant reliability and moldability free of burr and having good thermal hardness and useful for sealing semiconductors by compounding an epoxy resin, a curing agent, a filler and a polyfunctional silane coupling agent. CONSTITUTION:An epoxy resin preferably containing biphenyl epoxy resin having a skeleton of the formula (R<1>-R<8> are H, 1-4C alkyl or halogen) in an amount of >=30wt.% based on the whole epoxy resin, (B) a curing agent (preferably a novolak resin) in a A:B chemical equivalent ratio of 1:(0.5-0.6), especially 0.8-1.3, (C) 5-90wt.% or a filler (preferably molted silica), (D) a polyfunctional silane coupling agent in an amount of 0.1-5 pts.wt., preferably 0.2-3 pts.wt., per 100 pts.wt. of the component C and, if necessary, a curing agent, a flame retardant, etc., the component C being surface-treated with the component D, are melted and kneaded with each other to provide the objective resin composition.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an epoxy resin composition for encapsulating a semiconductor device. More specifically, for soldering when mounting resin-sealed semiconductor devices, we use epoxy resin compositions for semiconductor encapsulation that prevent cracks from occurring in the encapsulation resin during the process, especially those with excellent moisture resistance and moldability. The present invention relates to an epoxy resin composition for semiconductor encapsulation.

<Prior Art> In recent years, in the field of semiconductor integrated circuits, along with the development of technologies for higher integration and higher reliability, automation of the process of assembling semiconductor devices onto wiring boards has been promoted. For example, when attaching a flat package type semiconductor device to a circuit board, conventionally each lead pin was soldered individually, but recently the entire semiconductor device is immersed in a solder bath heated to 250°C or higher to solder the surface. The implementation method is adopted. Therefore, when soldering a package sealed with conventional sealing resin, cracks sometimes occur in the resin part, reducing reliability and making it unusable as a product.

In addition, as a method for encapsulating semiconductors, the most common method is to use a composition made of epoxy resin with a hardening agent, a filler, etc., set the semiconductor element in a mold, and encapsulate it by transfer molding or the like. It is being said.

The properties required of these semiconductor encapsulating resins include reliability, soldering heat resistance, and moldability, and reliability includes moisture resistance, and moldability includes Paris and hardness when heated.

Moisture resistance here means that when a resin-encapsulated semiconductor device is placed in a high-temperature, high-humidity environment, moisture may enter through the encapsulation resin or the interface between the encapsulation resin and the lead frame, causing the semiconductor to fail. In recent years, as the degree of integration of semiconductors has improved, a higher degree of moisture resistance has become required.

In order to improve the moisture resistance of the sealing resin, a silane coupling agent is usually added, and specifically, a method of adding epoxy silane (Japanese Patent Publication No. 17640/1983)
and a method of adding vinyl silane (JP-A-62-22
3219, Japanese Unexamined Patent Publication No. 57-155753), etc. have been proposed.

Furthermore, as a conventional method for improving the solder crack resistance of the sealing resin, a method using a biphenyl type epoxy resin (Japanese Patent Laid-Open No. 63-251419) has been proposed.

<Problem to be solved by the invention> However, in the method of adding epoxy silane or vinyl silane to improve moisture resistance, the addition of these does not sufficiently improve moisture resistance or soldering heat resistance, and it is difficult to use them as a product. It was difficult to do so.

In addition, in the method using biphenyl-type epoxy resin and epoxy silane, the solder crack resistance of the sealing resin is improved to some extent, but not only is it not at a satisfactory level.
In addition to low moisture resistance, it had problems such as low hardness when heated and a lot of flaking during molding, making it impractical.

Therefore, the object of the present invention is to solve the problems of the above-mentioned epoxy resin compositions, and to develop an epoxy resin composition that has reliability such as soldering heat resistance and moisture resistance, and excellent moldability such as Paris and hot hardness. An object of the present invention is to provide a resin-sealed semiconductor for surface mounting.

Means for Solving the Problems The present inventors have discovered that by using a polyfunctional silane coupling agent, the above problems can be achieved and an epoxy resin composition for semiconductor encapsulation that meets the purpose can be obtained. , arrived at the present invention.

That is, the present invention comprises an epoxy resin (A), a curing agent (B)
, filler (C) and polyfunctional silane coupling agent (D
) An epoxy resin composition for semiconductor encapsulation is provided.

The configuration of the present invention will be explained in detail below.

The epoxy resin (A) in the present invention is not particularly limited as long as it has at least two epoxy groups in its molecule, and specific examples thereof include cresol novolac type epoxy resin, phenol novolac type epoxy resin, etc. , biphenyl type epoxy resin (a) having a skeleton represented by the following formula (I) (R1 to R8 represent a hydrogen atom, a lower alkyl group of 01 to C4, or a halogen atom) Novolac type epoxy resins represented, ... [F] Various novolac type epoxy resins synthesized from bisphenol A, resorcin, etc., bisphenol A type epoxy resins, linear aliphatic epoxy resins, alicyclic epoxy resins , heterocyclic epoxy resins and halogenated epoxy resins.

Depending on the application, two or more types of epoxy resins may be used together, but for semiconductor encapsulation resins, from the viewpoint of soldering heat resistance, the total epoxy resin should contain at least 30% by weight of biphenyl-type epoxy resin (a). is preferred.

A preferred specific example of the biphenyl-type epoxy resin (a) is 4,4'-bis(2,3-epoxypropoxy)
biphenyl, 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-bromobiphenyl, 4,4'-bis(2,
Examples include 3-epoxypropoxy) 3.3', 5.5'-tetraethylbiphenyl and 4.4'-bis(2,3-epoxypropoxy)-3,3', 5.5'-tetrabutylbiphenyl. .

The curing agent (B) in the present invention is an epoxy resin (^)
It is not particularly limited as long as it is cured by reacting with the resin, and specific examples thereof include phenol novolak resin, cresol novolak resin, novolac resin represented by the following formula 0, ... slight bisphenol A and resorcinol. Examples include various novolac resins synthesized from various novolak resins, various polyhydric phenol compounds, acid anhydrides such as maleic anhydride, phthalic anhydride, and pyromellitic anhydride, and aromatic amines such as metaphenylene diamine, diaminodiphenylmethane, and diaminodiphenylsulfone. It will be done. For encapsulating semiconductor devices, novolak resins such as phenol novolac and cresol novolak are preferably used from the viewpoint of heat resistance, moisture resistance and storage stability, and two or more types of curing agents may be used in combination depending on the purpose.

In the present invention, the compounding ratio of the epoxy resin (A) and the curing agent (B) is such that the chemical equivalent ratio of (B) to (A) is 0.5 to 1°6, particularly from the viewpoint of mechanical properties and moisture resistance. 0.8
It is preferably in the range of 1.3 to 1.3.

In addition, in the present invention, epoxy resin (A) and curing agent (B
) A curing catalyst may be used to accelerate the curing reaction.

The curing catalyst is not particularly limited as long as it promotes the curing reaction, and examples thereof include 2-methylimidazole, 2,4-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, and 2-phenyl-4-methyl. Imidazole compounds such as imidazole and 2-heptadecyl imidazole, triethylamine, benzyldimethylamine, a-methylbenzyldimethylamine, 2-
(dimethylaminomethyl)phenol, 2.4.6-)
Lis(dimethylaminomethyl)phenol, tertiary amine compounds such as l,8-diazabicyclo(5,4,0)undecene-7, zirconium tetramethoxide, zirconium tetrapropoxide, tetrakis(acetylacetonato)zirconium, tri( Examples include organometallic compounds such as acetylacetonato)aluminum, and organic phosphine compounds (F) such as triphenylphosphine, trimethylphosphine, triethylphosphine, tributylphosphine, tri(p-methylphenyl)phosphine, and tri(nonylphenyl)phosphine. Among them, from the viewpoint of moisture resistance, organic bosphine compounds (F) are preferred, and triphenylphosphine is particularly preferably used.

Two or more of these curing catalysts may be used in combination depending on the application, and the amount added is preferably in the range of 0.1 to 10 parts by weight per 100 parts by weight of the epoxy resin (A).

The filler (C) in the present invention includes fused silica, crystalline silica, calcium carbonate, magnesium carbonate, alumina, magnesia, clay talc, calcium silicate,
Examples include titanium oxide, asbestos, and glass fiber. Among them, fused silica is preferably used because it has a large effect of lowering the coefficient of linear expansion and is effective in reducing stress. Furthermore, the proportion of filler (C) is 75 to 90% by weight of the whole.
and the filler contains 40% by weight or more of crushed fused silica (C') with an average particle size of 10- or less based on the total silica,
Preferable in terms of soldering heat resistance.

Note that the average particle size here refers to the particle size that accounts for 50% of the cumulative weight (
median diameter).

The silane coupling agent (D) in the present invention is a polyfunctional silane coupling agent. Specific examples of the polyfunctional silane coupling agent (D) include those represented by the following formula (2).

X-N-R'-8i (OR2) n (R1 is a divalent hydrocarbon group having 1 to 20 carbon atoms, R2 is a hydrogen atom, m hydrocarbon groups having 1 to 20 carbon atoms, n is 1 to
each represents an integer of 3, X represents a 2-aminoethyl group, glycidyl group, methacrylic group, or hydride group, Y represents an allyl group, trimethoxysilylpropyl group, dimethoxymethylglobyl group, or glycidyl group) Specific examples of the polyfunctional silane coupling agent (D) in the invention include 3-[N-allyl-N(2-aminoethyl)]aminopropyltrimethoxysilane, N,N-bis[3-(
trimethoxysilyl>provircomethacrylamide, 3
-(N-allyl-N-glycidyl)aminopropyltrimethoxysilane, 3-(N,N-diglycidyl)aminopropyltrimethoxysilane, 3-[N-allyl-N
-glycidyl)aminopropyltrimethoxysilane and 3-(N-allyl-N-methacryl)aminopropyltrimethoxysilane.

The amount of these polyfunctional silane cutting agents (D) added is usually 1001! 0.1 to 5 parts by weight, preferably 0.2 to 3 parts by weight, particularly preferably 0.
The amount is 3 to 1.5 parts by weight, and other silane coupling agents such as -functional epoxysilane, mercaptosilane, aminosilane, and vinylsilane may be used in combination depending on the purpose.

In the present invention, it is preferable from the viewpoint of reliability that the filler (C) is previously surface-treated with a polyfunctional silane coupling agent (D).

The resin composition for semiconductor encapsulation of the present invention includes halogen compounds such as halogenated boxy resin, flame retardants such as phosphorus compounds, flame retardant aids such as antimony trioxide, colorants such as carbon black and iron oxide, and silicone. Elastomers such as rubber, silicone oil, styrene block copolymers, olefin copolymers, modified nitrile rubber, modified polybutadiene rubber, thermoplastic resins such as polyethylene, coupling agents such as titanate coupling agents, long chain fatty acids , metal salts of long chain fatty acids, esters of long chain fatty acids, amides of long chain fatty acids, mold release agents such as paraffin wax, and crosslinking agents such as organic peroxides can be optionally added.

The epoxy resin composition of the present invention is preferably produced by melt-kneading, for example, using a Banbury mixer,
It is produced by melt-kneading using a known mixing method such as a kneader roll, a single-screw or two-wheel extruder, and a coney goo.

<Example> Hereinafter, the present invention will be specifically explained with reference to Examples.

For the formulation shown in Table 1, various silane coupling agents shown in Table 2 and various fused silicas shown in Table 3 were tri-blended using a mixer at the composition ratios shown in Table 4. This was heated and mixed for 5 minutes using a mixing roll with a roll surface temperature of 90° C., then cooled and pulverized to produce an epoxy-containing composition.

Using this composition, 1
Post-curing was performed for 5 hours at 75°C for 4 minutes. After post-curing, the physical properties of each composition were measured using the following physical property measuring method.

Soldering heat resistance: 85℃/85% for 24 80pin QFPs
After humidifying at RH for 50 hours, the QFPs were immersed in a solder bath heated to 260° C. for 10 seconds to determine the percentage of QFPs that did not develop cracks.

Reliability: 120℃/85 using 44pin QFP
USPCBT was performed at %RH and a bias voltage of 15 V, and the time required for the cumulative porosity to reach 50% was determined.

Furthermore, using the epoxy resin composition produced by the above method, moldability was evaluated by the following method.

Flash: Resin flash was measured using a flash mold using a low-pressure transfer molding method.

Hardness when heated: 175℃× by low pressure transfer molding method
It was molded for 2 minutes and the hardness (Shore D) when heated was measured.

The above evaluation results are summarized in Table 4.

As seen in Table 4, the compositions (Examples 1 to 3) using the polyfunctional silane coupling agent of the present invention have solder heat resistance,
Excellent balance in reliability, Paris and hot hardness.

On the other hand, compositions that do not use the polyfunctional silane coupling agent of the present invention (Comparative Examples 1 to 4) are inferior in solder heat resistance, reliability, Paris, and hardness when heated.

In addition, the epoxy resin compositions of the present invention containing 30% by weight or more of a specific epoxy resin (Examples 4 to 5) have excellent moldability such as reliability, Paris, and hot hardness, and have excellent soldering heat resistance. It's getting even better.

Furthermore, the epoxy resin compositions of the present invention containing specific fused silica (Examples 6 to 9) have further improved solder heat resistance.

<Effects of the Invention> Because the epoxy resin composition of the present invention contains a polyfunctional silane coupling agent, a curing agent, a filler, and an epoxy resin, it has excellent solder heat resistance, reliability, and moldability, and is suitable for semiconductor encapsulation. It has ideal performance as a stop.

Claims (2)

[Claims] (1) Epoxy resin (A), curing agent (B), filler (C
) and a polyfunctional silane coupling agent (D). (2) Epoxy resin (A) has the following formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(I) (However, R^1 to R^8 are hydrogen atoms, C_1 to C_4
represents a lower alkyl group or a halogen atom. The epoxy resin composition for semiconductor encapsulation according to claim 1, characterized in that the total epoxy resin (A) contains 30% by weight or more of the epoxy resin (a) having a skeleton represented by the following formula.