JP3192255B2 - Resin composition for semiconductor encapsulation - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin composition for encapsulating a semiconductor, and more particularly to a transistor, an IC and an LS.
The present invention relates to a highly reliable semiconductor sealing resin composition for sealing a semiconductor such as I by transfer molding.

[0002]

2. Description of the Related Art As a method for encapsulating semiconductor elements such as transistors, ICs and LSIs, a method by transfer molding of an epoxy resin is adopted as a method suitable for low cost and mass production. It is at a level that can be fully used by improvement. However, with the trend toward smaller and lighter electronic products, a new mounting method called surface mounting of semiconductor packages was born.
A major problem has arisen in the reliability of epoxy resin-sealed semiconductor products. That is, at the time of soldering the semiconductor package to the circuit board, after the semiconductor package is temporarily fixed to the circuit board, a very high temperature condition of about 240 ° C. is applied when reflowing the semiconductor package to perform soldering by reflow processing. Therefore, the sealing package is damaged by the thermal expansion of the hygroscopic water, a gap is generated between the silicon pellet and the resin interface, or a crack is generated in the package itself, so that the reliability of the semiconductor product is significantly deteriorated.

Conventionally, in order to solve this problem, the epoxy resin is made heat resistant (Japanese Patent Application Laid-Open No. Sho 61-168620), or the epoxy resin is made flexible (Japanese Patent Application Laid-Open No. Sho 62-168620).
−115850,62−116654,62−1281
62, 62-136860) have been proposed, but none of these methods is sufficient and could not reach a level that guarantees 100% reliability of semiconductor products after reflow processing.

[0004]

SUMMARY OF THE INVENTION The present invention provides a resin composition for semiconductor encapsulation for preventing the deterioration of reliability after reflow treatment in the surface mounting of such semiconductor products.

[0005]

SUMMARY OF THE INVENTION The present invention relates to a resin composition for semiconductor encapsulation comprising an epoxy resin, a phenol novolak resin, a curing accelerator and an inorganic filler as main components.
As a filler, a polyimide resin having an average particle diameter of 20 to 70 μm, a spherical particle having a maximum particle diameter of 150 μm or less, having pores of 20 to 80 vol% of its own volume, and having a softening temperature of 200 to 240 ° C. , 1 to 2 in the total amount of the resin composition
It is a resin composition for semiconductor encapsulation containing 0 wt%.

[0006] The epoxy resin used in the present invention may be any one used in a usual resin composition for encapsulating a semiconductor. For example, cresol novolak type epoxy, trifunctional epoxy, biphenyl type bifunctional epoxy, bisphenol type epoxy, Although brominated epoxy etc. are mentioned, it does not specifically limit. These epoxy resins may be used alone or in combination. The phenol novolak resin of the curing agent may be any one used in a usual resin composition for semiconductor encapsulation, for example, a phenol novolak type,
Examples thereof include cresol novolak type and modified resins thereof, but are not particularly limited. These may be used alone or in combination.

The curing accelerator may be any one which promotes the reaction between the epoxy group and the phenolic hydroxyl group, and those commonly used in resin compositions for semiconductor encapsulation can be widely used. Tertiary amines,
Examples thereof include organic phosphorus compounds such as imidazoles, DBU, and triphenylphosphine, which can be used alone or in combination. Further, examples of the inorganic filler used in the present invention include crystalline silica, fused silica, alumina, calcium carbonate, talc, mica, and glass fiber.

The polyimide filler used in the present invention is thermoplastic and has an average particle diameter of 20 to 70 μm and a maximum particle diameter of 1 μm.
A spherical shape of 50 μm or less is preferable, and even if it has a particle size or an irregular shape other than this, although it has an action of preventing package cracking at the time of reflow treatment, fluidity at the time of molding is inferior,
There are problems such as unfilling, wire flow, and pad shift. The pores inside the polyimide filler are essential for absorbing and relaxing the high-pressure steam gas generated inside the package during the reflow process, and the high-pressure steam gas at about 240 ° C. At high speed, and is absorbed by reaching the pores inside the polyimide, thereby preventing package cracking during reflow.

When the high temperature steam gas of about 240 ° C. rapidly diffuses into the pores inside the polyimide filler, the pressure of the steam gas is reduced by the cooling due to the expansion of the gas, which is effective for preventing package cracking. The volume of the pores needs to be 20 to 80 vol%, but preferably 50 to 80 vol%.
80 vol%. When the content is 80 vol% or more, the strength of the polyimide filler itself becomes weak, and the polyimide filler is destroyed by a compounding process of the sealing material or a molding pressure during molding, which is not preferable. The softening temperature of the polyimide filler is 200 to 240.
C. is preferable. If the temperature is 200 [deg.] C. or lower, it is deformed or broken at the time of molding at 165 to 185 [deg.] C. If it is 240 [deg.] C. or higher, it is not softened at around 240 [deg.] C. during reflow, and the water vapor absorbing effect is inferior. It is appropriate that the amount added to the resin composition for semiconductor encapsulation is 1 to 20% by weight based on the total amount of the resin composition. When the amount is 1% by weight or less, there is no effect, and when the amount is 20% by weight or more, the linear expansion coefficient of the resin composition. Is undesirably large.

[0010]

The present invention will be described below by way of examples. The mixing ratio is shown in parts by weight. Example 1 Biphenyl type epoxy resin (oiled shell, YX-4000H, epoxy equivalent 190, softening point 107 ° C) 90 parts by weight brominated epoxy resin (Nippon Kayaku, BREN, epoxy equivalent 270, softening point 70 ° C) 10 Parts by weight Phenol novolak resin (Sumitomo Durez, PR series, hydroxyl equivalent 104, softening point 110 ° C) 47 parts by weight Fused silica (1: 1 blend of Tatsumori RD-8 and Denka FB-74) 400 parts by weight Polyimide filler A 10 Parts by weight Triphenylphosphine 2 parts by weight γ-glycidoxypropyltrimethoxysilane (Nihon Unicar A-187) 4 parts by weight Antimony trioxide 10 parts by weight Carnauba wax 3 parts by weight Carbon black 2 parts by weight is sufficiently mixed at room temperature. And then kneaded at 80-100 ° C using a twin-screw roll, cooled and then ground Tableted Te to obtain a resin composition for semiconductor encapsulation.

The polyimide filler used in the present invention is represented by the following formulas (1) and (2):

[0012]

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[0013]

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Into a reactor at a molar ratio of 1: 1, a foaming agent was added in an amount of 5 wt% based on the formula (1), and a mixed solvent of N-methyl-2-pyrrolidone and toluene was used as a reaction solvent.
Dehydration reflux was performed at 0 ° C. for 5 hours. At this time, the particle size of the polyimide filler was adjusted by adjusting the stirring speed of the reaction solution to 150 to 500 rpm. After completion of the reaction, the reaction product was collected by filtration, dried at 150 ° C. under vacuum,
C. for 1 hour to obtain a polyimide filler. Table 1 shows the properties of the polyimide fillers A, B, and C. Example 2 In the same manner as in Example 1, a resin composition for semiconductor encapsulation shown in Table 1 was obtained.

Comparative Examples 1 to 3 In the same manner as in Example 1, semiconductor sealing resin compositions having the compositions shown in Table 1 were obtained. The resin compositions for semiconductor encapsulation of Examples 1 and 2 and Comparative Examples 1 to 3 were transferred using a transfer molding machine to 17
Molding was performed at 5 ° C. to obtain a test piece for evaluation. Table 2 shows the evaluation results.

Evaluation method: Reflow crack resistance: 52 pQF containing a simulated element
Using P (14 × 14 × 2.0 mm, chip 6 × 6 mm), judgment was made based on the presence or absence of a package crack after reflow treatment (after 168H moisture absorption treatment at 85 ° C. and 85% RH, and 240 ° C. reflow treatment).

[0017]

[Table 1]

[0018]

[Table 2]

[0019]

The resin composition for semiconductor encapsulation of the present invention is excellent in preventing package cracking during reflow treatment, and is useful for mounting a semiconductor package encapsulated with the composition on a circuit board before reflow. Drying before packaging can be omitted, and a highly reliable package can be obtained.

──────────────────────────────────────────────────の Continuation of the front page (51) Int.Cl. ⁷ identification code FI // (C08L 63/00 79:08) (58) Investigated field (Int.Cl. ⁷ , DB name) C08L 63/00- 63/10 C08L 79/08 H01L 23/29

Claims (1)

(57) [Claims] 1. A semiconductor encapsulation resin composition comprising an epoxy resin, a phenol novolak resin, a curing accelerator and an inorganic filler as main components, wherein the resin composition has a spherical shape having an average particle size of 20 to 70 μm and a maximum particle size of 150 μm or less. And a polyimide resin having a pore portion of 20 to 80 vol% of its own volume and having a softening temperature of 200 to 240 ° C. as a filler, and contains 1 to 2 in the total amount of the resin composition.
A resin composition for semiconductor encapsulation, comprising 0 wt%.