JP2825572B2 - Resin composition for semiconductor encapsulation - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a resin composition for semiconductor encapsulation,
The present invention relates to a resin composition suitable for sealing a semiconductor device requiring solder heat resistance, such as a surface-mounted semiconductor device.

[Conventional technology]

In the fields of electrical equipment and electronic components, especially semiconductors, high-density packaging and multifunctionality are on the rise, and the material that seals this is a resin composition with excellent heat resistance to high-temperature solder in the mounting process. The development of products is strongly desired.

Conventionally, as a resin composition for semiconductor encapsulation, an epoxy resin represented by an o-cresol novolac type epoxy resin, a resin composition containing a curing agent and silica as main components have excellent moldability and reliability. Therefore, it has become mainstream.

[Problems to be solved by the invention]

As a recent trend, for resin-encapsulated semiconductor devices,
Due to the flow of high-density mounting described above, semiconductor devices are being changed to surface-mount type semiconductor devices. In such a surface-mount type semiconductor device, unlike the conventional insertion type semiconductor device, the entire semiconductor device is exposed to a soldering temperature of 200 ° C. or more in the step of soldering to the substrate. At this time, cracks occur in the sealing resin, and a problem has arisen that the reliability of the semiconductor device is significantly reduced. From this point, many studies have been made on using imide-based resins having excellent heat resistance for the purpose of improving resin strength, but cured products of imide resins have problems in terms of flexibility and moldability. Yes, it has been studied to balance moldability and heat resistance by using the epoxy resin in combination. However, the imide resin and the epoxy resin have poor compatibility and it is difficult to always obtain stable performance.

An object of the present invention is to provide a sealing resin composition applicable to a resin-sealed semiconductor device requiring solder heat resistance.

[Means for solving the problem]

The present inventors have conducted intensive studies for the purpose of improving the heat resistance of the resin composition by using an epoxy resin and an imide resin together, and as a result, using a bismaleimide having a rigid biphenyl skeleton in the imide resin, By using an epoxy resin having the same biphenyl skeleton as the bismaleimide in the molecular chain, they have found that excellent heat resistance can be obtained, and have completed the present invention.

That is, the present invention provides a resin composition consisting essentially of a bismaleimide (A), an epoxy resin (B), an epoxy curing agent (C), and an inorganic filler (D), wherein the bismaleimide (A) has a general formula: I): (R _{1 to} R ₄ represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.)
And the epoxy resin (B) has the general formula (II): Wherein R _{5 to} R ₈ represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. 5 to 50% by weight of an epoxy resin represented by the following formula:

The bismaleimide (A) used in the present invention has the general formula (I): (R _{1 to} R ₄ represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.) A bismaleimide represented by the general formula (III): (Wherein R _{1 to} R ₄ represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms).

Specific examples of such diamines include 4,4'-bis (4
-Aminophenoxy) biphenyl, 4,4'-bis (3-
Aminophenoxy) biphenyl, 4,4'-bis (4-aminophenoxy) -3,3 ', 5,5'-tetramethylbiphenyl, 4,4'-bis (3-aminophenoxy) -3,3',
5,5'-tetramethylbiphenyl, 4,4'-bis (4-aminophenoxy) -3,3 ', 5,5'-tetraethylbiphenyl, 4,4'-bis (3-aminophenoxy) -3, 3 ′,
5,5'-tetraethylbiphenyl, 4,4'-bis (4-aminophenoxy) -3,3 ', 5,5'-tetrapropylbiphenyl, 4,4'-bis (3-aminophenoxy) -3,
3 ', 5,5'-tetrapropylbiphenyl, 4,4'-bis (4-aminophenoxy) -3,3', 5,5'-tetrabutylbiphenyl, 4,4'-bis (3-aminophenoxy )
-3,3 ', 5,5'-tetrabutylbiphenyl and the like.

Bismaleimides derived from these diamines are:
4,4'-bis (4-maleimidophenoxy) biphenyl, 4,4'-bis (3-maleimidophenoxy) biphenyl and 4,4'-bis (4-maleimidophenoxy), respectively
-3,3 ', 5,5'-tetramethylbiphenyl, 4,4'-bis (3-maleimidophenoxy) -3,3', 5,5'-tetramethylbiphenyl, 4,4'-bis (4 -Maleimidophenoxy) -3,3 ', 5,5'-tetraethylbiphenyl, 4,
4'-bis (3-maleimidophenoxy) -3,3 ', 5,5'
-Tetraethylbiphenyl, 4,4'-bis (4-maleimidophenoxy) -3,3 ', 5,5'-tetrapropylbiphenyl, 4,4'-bis (3-maleimidophenoxy)-
3,3 ', 5,5'-tetrapropylbiphenyl, 4,4'-bis (4-maleimidophenoxy) -3,3', 5,5'-tetrabutylbiphenyl, 4,4'-bis (3- Maleimidophenoxy) -3,3 ', 5,5'-tetrabutylbiphenyl and the like, and one or more of these are used.

In addition, bismaleimides other than those described above can be appropriately used in admixture, but the use ratio is preferably 20% by weight or less based on the total bismaleimide.

Other bismaleimides include, for example, N, N '
-Ethylene bismaleimide, N, N'-hexamethylene bismaleimide, N, N '-(1,3-phenylene) bismaleimide, N, N'-(1,4-phenylene) bismaleimide, bis (4-maleimide Phenyl) methane, bis (4-maleimidophenyl) ether, bis (3-chloro-4-maleimidophenyl) methane, bis (4-maleimidophenyl) sulfone, bis (4-maleimidocyclohexyl) methane, 1,4-bis ( Maleimidomethyl) cyclohexane, 1,4-bis (maleimidophenyl) cyclohexane, 1,4-bis (maleimidomethyl) benzene, 1,3-
Bis (3-maleimidophenoxy) benzene, bis [4
-(3-maleimidophenoxy) phenyl] methane, 1,
1-bis [4- (3-maleimidophenoxy) phenyl] ethane, 1,2-bis [4- (3-maleimidophenoxy) phenyl] ethane, 2,2-bis [4- (3-maleimidophenoxy) phenyl] Propane, 2,2- [4-
(3-maleimidophenoxy) phenyl] butane, 2,2
-Bis [4- (3-maleimidophenoxy) phenyl]
-1,1,1,3,3,3-hexanefluoropropane, bis [4
-(3-maleimidophenoxy) phenyl] ketone, bis [4- (3-maleimidophenoxy) phenyl] sulfide, bis [4- (3-maleimidophenoxy) phenyl] sulfoxide, bis [4- (3-maleimidophenoxy) phenyl] ] Sulfone, bis [4- (3-maleimidophenoxy) phenyl] ether and the like.

As the epoxy resin (B), any resin having at least two epoxy groups in one molecule can be used.

 These are illustrated below.

Novolak type epoxy resins derived from novolak resins which are reaction products of phenols such as phenol, cresol and resorcinol with aldehydes, and aralkyl resins which are reaction products of the above phenols and aralkyl ethers The aralkyl type epoxy resin to be used is preferable from the viewpoint of heat resistance and electric characteristics.

In addition, epoxy resins derived from compounds having two or more active hydrogens in one molecule, such as bisphenol A, bisphenol F, resorcinol, bishydroxydiphenyl ether, tetrabromobisphenol A,
Polyhydric phenols such as trihydroxyphenylmethane, tetrahydroxyphenylethane, and alkanetetrakisphenol; polyhydric alcohols such as ethylene glycol, neopentyl glycol, glycerin, trimethylolpropane, pentaerythritol, diethylene glycol, and polypropylene glycol; ethylenediamine;
There are epoxy resins obtained by reacting amines such as aniline and bis (4-aminophenyl) methane; polycarboxylic acids such as adipic acid, phthalic acid and isophthalic acid with epichlorohydrin or 2-methylepichlorohydrin. One or more resins are used.

Further, as the epoxy resin (B), an epoxy resin modified with a silicone compound such as an oily or rubbery material can be used.

For example, there are silicone-modified epoxy resins produced by the methods disclosed in JP-A-62-270617 and JP-A-62-273222.

However, in order to improve the compatibility between the epoxy resin and the bismaleimide and to improve the moldability and heat resistance of the resin composition, the epoxy resin contains the general formula (II): (R _{5 to} R ₈ represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms).
It is necessary to use 10 to 30% by weight. General formula (II)
If the epoxy resin represented by the formula is less than 5% by weight, good compatibility cannot be obtained between the imide resin and the epoxy resin, and if it exceeds 50% by weight, the heat resistance rapidly decreases.

Specific examples of the epoxy resin represented by the general formula (II) 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'-tetraethylbiphenyl, 4,4'-bis (2 , 3-epoxypropoxy) 3,3'5,5'-tetrapropylbiphenyl, 4,4'-
Bis (2,3-epoxypropoxy) -3,3 ', 5,5'-tetrabutylbiphenyl and the like;
More than types are used.

The epoxy curing agent (C) contains a compound having two or more phenolic hydroxyl groups in one molecule as an essential component.

Specifically, a novolak phenol resin which is a reaction product of a phenol such as phenol, kusol, and resorcinol with an aldehyde, an aralkyl phenol resin which is a reaction product of the above phenol with an aralkyl ether, trihydroxyphenyl Examples include polyhydric phenols such as methane, tetrahydroxyphenylethane, and alkanetetrakisphenol, and one or more of these are used.

Further, amines and acid anhydrides can be used in combination with the above compounds.

The blending amounts of bismaleimide (A), epoxy resin (B) and epoxy curing agent (C) are as follows.
The total amount of the epoxy resin (B) and the epoxy curing agent (C) is 10 to 500 parts by weight, preferably 25 to 100 parts by weight.
~ 300 parts by weight. The ratio of the epoxy resin (B) to the epoxy curing agent (C) is in the range of 0.1 to 10, preferably 0.5 to 2, in equivalent ratio of the epoxy curing agent (C) to the epoxy resin (B). is there.

As the inorganic filler (D), powders of silica, alumina, nitrogen silicon, silicon carbide, talc, calcium silicate, calcium carbonate, mica, clay, titanium white and the like;
Fibrous bodies such as glass fiber and carbon fiber are exemplified.

Among these, crystalline silica and / or fusible silica are preferred from the viewpoint of the coefficient of thermal expansion and thermal conductivity.

Further, considering the fluidity during molding of the resin composition, the shape is preferably spherical, or a mixture of spherical and amorphous.

The blending amount of the inorganic filler (D) must be 100 to 900 parts by weight based on 100 parts by weight of the total amount of the bismaleimide (A), the epoxy resin (B) and the epoxy curing agent (C). , Preferably 200 to 600 parts by weight.

In addition, the inorganic filler (D) is preferably used in combination with a coupling agent for the purpose of improving the adhesiveness to a resin from the viewpoint of mechanical strength, heat resistance, and the like. Titanate-based, aluminate-based and zircoaluminate-based coupling agents can be used, among which silane-based coupling agents are preferred, and in particular,
A silane coupling agent having a functional group that reacts with the thermosetting resin is most preferable.

Examples of such silane coupling agents include vinyltrimethoxysilane, vinyltriethoxysilane, N-
(2-aminoethyl) 3-aminopropylmethyldimethoxysilane, N- (2-aminoethyl) 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-anilinopropyltrimethoxysilane, 3-gly Sidoxypropyltrimethoxysilane, 3
-Glycidoxypropylmethyldimethoxysilane, 2-
(3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane and the like can be mentioned, and one or more of these are used.

In the present invention, in curing the resin composition, it is desirable to use a curing accelerator. Examples of the curing accelerator include imidazoles such as 2-methylimidazole and 2-methyl-4-ethylimidazole; amines such as triethanolamine, triethylenediamine and N-methylmorpholine; tributylphosphine, triphenylphosphine, and tolyl. Organic phosphines such as phosphine; tetraphenylboron salts such as tetraphenylphosphonium tetraphenylborate and triethylammonium tetraphenylborate; and 1,8-cyaza-bicyclo (5,4,0) undecene-7 and derivatives thereof.

The curing accelerators may be used alone or in combination of two or more, and a radical initiator such as an organic peroxide or an azo compound may be used in combination.

The amount of these curing accelerators used is bismaleimide (A),
It is used in the range of 0.01 to 10 parts by weight based on 100 parts by weight of the total amount of the epoxy resin (B) and the epoxy curing agent (C).

In the resin composition, in addition to the above components, if necessary,
Fatty acids, fatty acid salts, release agents such as wax, bromo compounds, flame retardants such as antimony and phosphorus, coloring agents such as carbon black, various silicone oils, etc. are blended, mixed and kneaded to form molding materials. .

〔Example〕

Hereinafter, the present invention will be specifically described with reference to Synthesis Examples, Examples, and Comparative Examples.

Synthesis Example (Bismaleimide) The bismaleimide in the present invention was synthesized as follows.

Into a reaction vessel equipped with a stirrer and a thermometer, 43.2 g (0.44 mol) of maleic anhydride and 130 g of acetone are charged and dissolved. A solution of 73.6 g (0.2 mol) of 4,4'-bis (3-aminophenoxy) biphenyl in 515 g of acetone is added dropwise at room temperature, and the mixture is further stirred at 23 to 27 ° C for 3 hours.
After completion of the reaction, drying was performed to obtain bismaleamic acid as yellow crystals.

112 g of bismaleamic acid thus obtained was suspended in 300 g of acetone, and 9.6 g of triethylamine was added.
Stir at room temperature for 30 minutes.

0.4 g magnesium oxide (II), cobalt acetate (II)
After adding 0.04 g of 4H ₂ O, 52 g of acetic anhydride is added dropwise at 25 ° C. over 30 minutes, and the mixture is further stirred for 3 hours. After completion of the reaction, the generated crystals were filtered, washed, and dried to obtain bismaleimide.

The yield was 84.5 g, 80% of the theoretical yield, and the melting point was 195-200 ° C.

Examples 1 to 3 and Comparative Examples 1 and 2 The bismaleimide and epoxy resin (o
-Clay sol novolak type epoxy resin; EOCN-1020,
Nippon Kayaku Co., Ltd.) 4,4'-bis (2,3-epoxypropoxy) as an epoxy resin represented by the general formula (II)
−3,3 ′, 5,5′-tetramethylbiphenyl (YX-4000,
Yuka Shell Epoxy Co., Ltd.) and epoxy curing agent (novolak phenol resin; PN-80, Nippon Kayaku Co., Ltd.)
Was charged into a flask equipped with a stirrer at the ratio (parts by weight) shown in Table 1 and melt-mixed at 200 ° C. for 10 minutes, then spread in a stainless steel vat, quenched, and cooled with a resin composition (1) to
(5) was obtained.

A small amount of the above resin compositions (1) to (5) is taken on a slide glass placed on a hot plate adjusted to 130 ° C., and a cover glass is further covered from above, and left for 3 minutes. Thereafter, the slide glass was taken out from the hot plate, cooled slowly at room temperature, and the dissolved state was observed.

 Table 1 shows the results.

Examples 4 to 6 and Comparative Examples 3 and 4 The above resin compositions (1) to (5) and the other components (parts by weight) shown in Table 2 were mixed with a Henschel mixer, and further mixed at 100 to 130 ° C. 3 minutes with hot roll
Kneaded.

This mixture was cooled, pulverized, and tableted to obtain a molding resin composition.

A test piece for measuring physical properties was formed by transfer molding (180 ° C., 30 kg / cm ² , 3 minutes) using these molding resin compositions.

In addition, a test element (10 mm × 10 mm square) is mounted on the element mounting part of the lead frame for a flat package type semiconductor device, and the semiconductor device for test is transferred (180 ° C., 30 kg / cm ² , 3 minutes). I got

These test moldings are subjected to 180
Post-curing was performed at 6 ° C. for 6 hours.

 Table 3 shows the test results.

 The test method is as follows.

-Glass transition temperature: TMA method-Flexural strength: JIS K-6911-Spiral flow: EMMI 1-66-VPS test: Test semiconductor device at 121 ° C, 2
After standing for 24 hours in a pressure cooker tester at atmospheric pressure, it was immediately put into a 260 ° C. molten solder bath, and the number of semiconductor devices having cracks in the package resin was counted. The test value is indicated by a fraction, the numerator is the number of semiconductor devices having cracks, and the denominator is the total number of semiconductor devices subjected to the test.

〔The invention's effect〕

As described in the Examples and Comparative Examples, the resin composition for semiconductor encapsulation according to the present invention can efficiently impart the heat resistance of the imide resin and the moldability of the epoxy resin. When a surface-mount type semiconductor device to which reflow and flow soldering methods are applied is sealed, a highly reliable resin-encapsulated semiconductor device that exhibits excellent solder heat resistance and moldability and can be obtained It is a useful invention.

────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification symbol FI // (C08K 13/02 3:00 5: 3417) (56) References JP-A-3-119052 (JP, A) JP-A JP-A-2-302424 (JP, A) JP-A-3-185048 (JP, A) JP-A-1-275620 (JP, A) JP-A-1-210408 (JP, A) JP-A-62-146925 (JP) , A) (58) Field surveyed (Int. Cl. ⁶ , DB name) C08L 63/00-63/10 C08G 59/22 C08K 5/3417 H01L 23/29

Claims (3)

(57) [Claims] 1. Bismaleimide (A), epoxy resin (B), epoxy curing agent (C) and inorganic filler (D)
Wherein the bismaleimide (A) is represented by the general formula (I): (R _{1 to} R ₄ represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.)
And the epoxy resin (B) has the general formula (II): Wherein R _{5 to} R ₈ represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. 5 to 50% by weight of an epoxy resin represented by the following formula: 2. The resin composition for semiconductor encapsulation according to claim 1, wherein the epoxy curing agent (C) contains a compound having two or more phenolic hydroxyl groups in one molecule as an essential component. 3. The resin composition for semiconductor encapsulation according to claim 1, wherein the inorganic filler (D) is spherical silica or a mixture of spherical silica and amorphous silica.