JPH09176279A - Epoxy resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a semiconductor-sealing epoxy resin compsn. having a good shelf stability at around ordinary temp. (20 deg.C) and a soldering cracking resistance by incorporating thereinto a specific amt. of an inorg. filler and setting the glass transition temp. thereof prior to curing in a specific range. SOLUTION: This resin compsn. comprises as the indispensable components an epoxy resin, a phenolic resin curing agent, a curing accelerator, an inorg. filler, and a thermoplastic polymer, provided that it contains 80-90wt.% inorg. filler and has a grass transition temp. of 20 to 50 deg.C before curing of the whole resin compsn. The thermoplastic polymer to be used is desirably compatible with the epoxy resin or the phenolic resin curing agent, and desirably has its own grass transition temp. of 90 to 250 deg.C. Pref. examples of the thermoplastic polymer include polyarylates, polycarbonates, and polymethyl methacryalte.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an epoxy resin composition for semiconductor encapsulation, which is excellent in storability at room temperature.

[0002]

2. Description of the Related Art Conventionally, electronic parts such as diodes, transistors and integrated circuits are sealed with thermosetting resin.
Particularly in integrated circuits, an epoxy resin composition in which an ortho-cresol novolac type epoxy resin having excellent heat resistance and moisture resistance is cured with a phenol novolac resin, and fused silica as a filler or an inorganic filler such as crystalline silica is used is used. ing. However, in recent years, the chips have become larger and larger due to the high integration of integrated circuits, and the package has a conventional DI.
Small and thin QFP, S surface mounted from P type
OP, SOJ, TSOP, TQFP, PLCC have been changed. The demand for solder crack resistance of epoxy resins for semiconductor encapsulation has increased with the surface mounting, and filler-filled materials using low-viscosity epoxy resins have become the mainstream. However, both the epoxy resin and the phenol resin are becoming less viscous due to higher filling of the filler. Therefore, the preservability of the encapsulating resin composition is lowered. Therefore, it is desired to develop an epoxy resin composition for semiconductor encapsulation, which has good solder crack resistance by a high filler filling method and good storage stability.

[0003]

SUMMARY OF THE INVENTION The present invention addresses these problems by including an inorganic filler in an amount of 80 to 90% by weight so that the glass transition temperature before curing is 20 to 35 ° C. Another object of the present invention is to provide a solder crack resistant epoxy resin composition for semiconductor encapsulation, which has good storage stability at around room temperature (20 ° C.).

[0004]

The present invention provides an epoxy resin, a phenol resin curing agent, a curing accelerator, an inorganic filler,
And a thermoplastic polymer as an essential component, and an inorganic filler 8
An epoxy resin composition comprising 0 to 90% by weight and having a glass transition temperature of 20 ° C. to 50 ° C. before curing of all resin compositions, preferably a thermoplastic polymer,
Compatible with epoxy resin or phenol resin curing agent,
It is an epoxy resin composition for semiconductor encapsulation having a glass transition temperature of 90 to 250 ° C.

If it has the above-mentioned characteristics, it can be stored for a long time at around room temperature and can be molded without lowering the fluidity.
If the glass transition temperature before curing is less than 20 ° C., the storability is deteriorated, and if the glass transition temperature is left at room temperature for a long time, molding defects such as unfilling and gold wire flow occur. On the other hand, if the temperature exceeds 50 ° C., the fluidity and the solder crack resistance deteriorate. The glass transition temperature is a differential scanning calorimeter (2910MDS) manufactured by TA Instruments.
C) measuring range: -20 to 130 ° C, heating rate: 5 ° C /
min, amplitude: ± 1.0, measured in a stream of dry nitrogen.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The epoxy resin used in the present invention refers to all monomers, oligomers and polymers having an epoxy group. For example, biphenyl type epoxy compound, bisphenol type epoxy compound, phenol novolac type epoxy resin, cresol novolac type epoxy resin,
Examples thereof include triphenol methane type epoxy compounds, alkyl-modified triphenol methane type epoxy compounds, and triazine nucleus-containing epoxy resins.

Examples of the curing agent used in the present invention include phenol novolac resin, cresol novolac resin, dicyclopentadiene modified phenol resin, paraxylylene modified phenol resin, terpene modified phenol resin and triphenol methane compound, and particularly phenol novolac resin. Preferred are dicyclopentadiene modified phenolic resin, paraxylylene modified phenolic resin, metaxylylene modified phenolic resin, terpene modified phenolic resin, and mixtures thereof. Moreover, it is preferable to mix these curing agents so that the number of epoxy groups of the epoxy compound and the number of hydroxyl groups of the curing agent are matched.

The curing accelerator used in the present invention may be any one as long as it accelerates the curing reaction between the epoxy group and the hydroxyl group, and those generally used for sealing materials can be widely used. For example, 1,8-diazabicycloundecene,
Triphenylphosphine, dimethylbenzylamine and 2
-Methylimidazole, etc. may be mentioned, and they may be used alone or in combination.

As the inorganic filler used in the present invention, those generally used for the sealing material can be widely used.
Examples thereof include spherical fused silica powder, crushed fused silica powder, crystalline silica powder, secondary agglomerated silica powder, porous silica powder and alumina. The content in the entire resin composition is preferably 80 to 90% by weight, and if it is less than 80% by weight, the solder cracking property is deteriorated, and if it exceeds 90% by weight, the fluidity is deteriorated and molding failure occurs.

The thermoplastic polymer used in the present invention may be one compatible with an epoxy resin or phenol resin curing agent, and the glass transition temperature of the thermoplastic polymer itself is preferably 90 to 250 ° C. If the glass transition temperature is lower than 90 ° C, the proportion of the thermoplastic polymer used increases and the fluidity decreases, and if it exceeds 250 ° C, the thermoplastic polymer thickens and the fluidity decreases, which is not preferable. Incidentally, the measurement of the glass transition temperature of the thermoplastic polymer,
Seiko Electronics Differential Scanning Calorimeter (DSC220)
And measurement range: 0 to 300 ° C., heating rate: 10 ° C./mi
n, measured in a stream of dry nitrogen. Further, it is desirable that the thermoplastic polymer is melt-mixed in advance with an epoxy resin, a phenol resin curing agent or a mixture thereof before use. still,
The compatibility shown here means a temperature of 70 ° C. at which a generally used epoxy resin or phenol resin curing agent melts.
It shows that the thermoplastic polymer and the epoxy resin or phenol resin curing agent become uniformly transparent at ˜140 ° C. Preferred examples of the thermoplastic polymer include polyarylate, polycarbonate, polymethylmethacrylate and the like.

The epoxy resin composition of the present invention contains an epoxy resin, a curing agent, an inorganic filler, a curing accelerator and a thermoplastic polymer as essential components, but other than this, a silane coupling agent, a brominated epoxy may be added if necessary. Resins, antimony trioxide, flame retardants such as hexabromobenzene, colorants such as carbon black and red iron oxide, mold release agents such as natural wax and synthetic wax, and various additives such as low stress additives such as silicone oil and rubber. There is no problem in properly blending. Further, in order to produce the encapsulating epoxy resin composition of the present invention as a molding material, after the epoxy resin, the curing agent, the curing accelerator, the filler, and other additives are sufficiently uniformly mixed by a mixer or the like, Further, it can be melt-kneaded with a hot roll or a kneader, cooled, and then pulverized to obtain a sealing material. These molding materials can be applied to coating, insulation, sealing, etc. of transistors, integrated circuits, etc., which are electric or electronic parts.

[0012]

【Example】

[Example 1] The following composition-Fused mixture A 12.8 parts by weight-Spherical fused silica powder (average particle size 15 µm, specific surface area 1.0 m ² / cm ³ ) 85.0 parts by weight-1,8-diazabicyclo ( 5,4,0) Undecene-7 (DBU) 0.2 parts by weight Carbon black 0.5 parts by weight Carnauba wax 0.5 parts by weight are mixed in a mixer at room temperature, and the mixture is biaxially rotated at 70 to 100 ° C. −
Kneading with a mullet, cooling and pulverizing to obtain a molding material. [Melted mixture A] means biphenyl type epoxy resin (melting point 9
5 ° C., epoxy equivalent of 200 g / eq, 5.1 parts by weight, paraxylylene-modified phenol resin curing agent A (softening point 65
° C, hydroxyl equivalent 175 g / eq) 4.7 parts by weight, brominated epoxy resin (softening point 53 ° C, epoxy equivalent 360 g)
/ Eq) 1.0 part by weight and polyarylate (glass transition temperature 110 ° C.) 3.0 parts by weight are melt mixed at 150 ° C. The molding material obtained by crushing is tableted, and is 175 ° C. and 70 Kg by a low pressure transfer molding machine.
/ Cm ^2, the 6 × 6 mm of chip as a solder crack test was sealed in 52PQFP. The glass transition temperature was measured and the storability test was performed on the obtained molding material. Further, a solder crack test was conducted on the sealed test element.

<< Evaluation Method >> Spiral Flow: A mold for measuring spiral flow according to EMMI-I-66 was used, and the mold temperature was 175 ° C.
The measurement was performed at an injection pressure of 70 kg / cm ² and a curing time of 2 minutes. Storability test: Spiral flow fluidity of a molding material stored at 25 ° C. was measured over time, and spiral flow residual rate = [(spiral flow value after storage for a certain number of days) / (spiral flow value before storage) × 100] was evaluated by the number of days until it reached 90%.・ Solder crack test: sealed test device at 85 ℃,
It was treated in an environment of 85% RH for 120 hours and 168 hours, then immersed in a solder bath at 260 ° C. for 10 seconds, and then external cracks were observed with a microscope.

[Examples 2 and 3] [Comparative Examples 1 and 2] Compounding was carried out according to the formulation shown in Table 1, and molding materials were obtained in the same manner as in Example 1. The glass transition temperature was measured, the storability test and the solder crack test were performed on this molding material. Table 1 shows the test results. The raw materials used in other than Example 1 are as follows. [Melted mixture B]: Biphenyl type epoxy resin (melting point 9
5 ° C., epoxy equivalent 200 g / eq) 4.5 parts by weight, paraxylylene-modified phenol resin curing agent B (softening point 75
° C, hydroxyl equivalent 175 g / eq) 4.3 parts by weight, brominated epoxy resin (softening point 53 ° C, epoxy equivalent 360 g)
/ Eq) 1.0 part by weight and polyarylate (glass transition temperature 110 ° C.) 2.0 parts by weight are melt-mixed at 150 ° C. [Melted mixture C]: Biphenyl type epoxy resin (melting point 9
5 ° C., epoxy equivalent 200 g / eq 4.0 parts by weight, paraxylylene-modified phenol resin curing agent A (softening point 65
℃, hydroxyl equivalent 175g / eq 3.8 parts by weight, brominated epoxy resin (softening point 53 ℃, epoxy equivalent 360g
/ Eq) 1.0 part by weight and polycarbonate (glass transition temperature 130 ° C.) 3.0 parts by weight are melt-mixed at 150 ° C. -Biphenyl type epoxy resin: melting point 95 ° C, epoxy equivalent 200g / eq-paraxylylene-modified phenol resin curing agent A: softening point 65 ° C, hydroxyl equivalent 175g / eq-brominated epoxy resin: softening point 53 ° C, epoxy equivalent 360g / eq

Table 1 Example Comparative Example 1 2 3 12 Compounding (parts by weight) Melt mixture A 13.8 Melt mixture B 11.8 Melt mixture C 11.8 Biphenyl type epoxy resin 5.6 12.3 Paraxylylene-modified phenolic resin A 5.2 10.5 Brominated epoxy resin 1.0 1.0 Spherical Fused silica 85.0 87.0 87.0 87.0 75.0 DBU 0.2 0.2 0.2 0.2 0.2 Carbon black 0.5 0.5 0.5 0.5 0.5 Carnauba wax 0.5 0.5 0.5 0.5 0.5 Characteristics Spiral flow (cm) 120 90 100 110 80 Glass transition temperature (° C) 35 35 40 18 20 Solder crack Moisture absorption 120 hours 0/8 0/8 0/8 0/8 8/8 Moisture absorption 168 hours 3/8 0/8 0/8 0/8 8/8 Storability (days) 7 7 10 1 2

[0016]

EFFECT OF THE INVENTION The epoxy resin composition for semiconductor encapsulation of the present invention has good solder crack resistance for a thin package and has improved storage stability at room temperature (20 ° C.).

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C08L 63/00 NJX C08L 63/00 NJX H01L 23/29 H01L 23/30 R 23/31

Claims (4)

[Claims] An epoxy resin, a phenol resin curing agent,
A curing accelerator, an inorganic filler, and a thermoplastic polymer as essential components, containing 80 to 90% by weight of the inorganic filler, and the glass transition temperature of the entire resin composition before curing is 20 to 50 ° C. Epoxy resin composition for semiconductor encapsulation. 2. The epoxy resin composition for semiconductor encapsulation according to claim 1, wherein the thermoplastic polymer is compatible with an epoxy resin and / or a phenol resin curing agent. 3. The glass transition temperature of the thermoplastic polymer is
The epoxy resin composition for semiconductor encapsulation according to claim 1 or 2, which has a temperature of 90 to 250 ° C. 4. The epoxy resin composition for semiconductor encapsulation according to claim 1, wherein the thermoplastic polymer is polyarylate or polycarbonate.