JP3346979B2 - Resin composition for sealing electronic parts - 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 sealing electronic parts with windows, such as a solid-state image sensor, which has excellent dimensional stability and in which penetration of moisture from the outside is problematic.

[0002]

2. Description of the Related Art Transistors, ICs, capacitors,
As a method for encapsulating electronic components such as diodes, a method by transfer molding of an epoxy resin composition is suitable for low-cost mass production, and has been widely put into practical use. ing. Recently, with the progress of multimedia, it is necessary to capture images and images to a personal computer or to transmit the images to a remote place instantly, and a small-sized, light-weight, low-cost solid-state imaging device is required. Conventionally, a solid-state imaging device is mounted on a ceramic case and bonded with a glass window, but it has high performance but is expensive. Therefore, to reduce costs, a method of mounting the element in a case molded with an epoxy resin composition and attaching a window made of glass or acrylic resin has been adopted, but the dimensional accuracy is lower than that of ceramic and moisture entering from the outside is It gradually penetrated the epoxy resin and eventually became dewed in the case, causing deterioration in characteristics. In general, in order to prevent water intrusion, a means of filling the resin with a filler having low hygroscopicity such as silica is used, but it is insufficient for this application and moisture diffuses inside the resin for a long period of time and Device. Therefore, in order to prevent the diffusion in the resin, a moisture absorbent such as a water absorbent polymer is being studied to fix the water content.However, when an organic moisture absorbent is used, swelling occurs and there is a problem in the dimensional stability and appearance of the product. Was.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a resin composition for sealing electronic parts, which has significantly improved dimensional stability and ability to block moisture entering from the outside.

[0004]

The present invention provides an epoxy resin, a phenol resin curing agent, a curing accelerator, an inorganic filler,
Silica gel is an essential component, the maximum particle size of the silica gel is 200 μm or less, the average particle size is 5 to 40 μm, the average pore volume is 0.1 to 50 ml / g, and the content of silica gel in the total composition is 1 to 30. % By weight, which is a resin composition for sealing electronic parts.

The silica gel has a particle diameter of 50-300.
There are innumerable holes of about Å and moisture can be absorbed and held. The volume of pores is important. If the average pore volume is less than 0.1 ml / g, the water adsorption capacity is low and not practical, and if the average pore volume exceeds 50 ml / g, the fluidity of the resin deteriorates. The maximum particle size is 200 μm
Above, the filling property is inferior. The average particle size is required to be in the range of 5 to 40 μm. If the average particle size is less than 5 μm, the fluidity is deteriorated. If the content in the whole resin composition is less than 1% by weight, the moisture absorption performance is low, and if it exceeds 30% by weight, the moisture permeability is higher than the moisture proof property, and the moisture intrusion prevention property is low. In addition, the fluidity is deteriorated, resulting in poor molding. The shape of the silica gel particles is not particularly limited, such as a crushed shape and a spherical shape.

As the inorganic filler, silica, alumina,
Clay, calcium carbonate, aluminum nitride, silicon nitride, etc. are preferred, and among these, silica is preferred. As the silica, fused silica or crystalline silica is preferably crushed or spherical, having an average particle size of 10 to 30 μm, and a maximum particle size of 150 μm.
m or less, but other particles may be used, or a mixture of these may be used. The total amount of silica and silica gel used in the present invention is 65% by weight to 90% of the total composition.
When the total amount of silica and silica gel, which needs to be in the range of 65% by weight, is 65 to 90% by weight, the dimensional stability and the hygroscopicity are particularly excellent.

[0007] The epoxy resin used in the present invention is not particularly limited as long as it contains two or more epoxy groups.
For example, cresol novolak type epoxy resin, trifunctional epoxy resin, biphenyl type epoxy resin, dicyclopentadiene type epoxy resin, bisphenol type epoxy resin, brominated epoxy resin and the like can be mentioned. These epoxy resins may be used alone or as a mixture. The phenol resin curing agent is not particularly limited as long as it contains two or more hydroxyl groups. For example, phenol novolak resin, cresol novolak resin, phenol aralkyl resin,
Examples include dicyclopentadiene-modified phenolic resins, triphenylmethane-type resins, and modified resins thereof. These phenol resins may be used alone or as a mixture. The amount of these curing agents is preferably such that the number of epoxy groups in the epoxy resin and the number of hydroxyl groups in the curing agent match. Examples of the curing accelerator include, but are not particularly limited to, imidazole, organic phosphine, tertiary amine, 1,8-diazabicyclo (5,4,0) undecene-7, and the like. These may be used alone or as a mixture.

The present invention comprises an epoxy resin, a phenolic resin curing agent, a curing accelerator, an inorganic filler, and silica gel as essential components. In addition to these, a surface treating agent for an inorganic filler such as a silane coupling agent may be used if necessary. , Flame retardants such as antimony trioxide, coloring agents such as carbon black and red iron oxide,
A release agent such as natural wax and synthetic wax and a low stress additive such as silicone oil and rubber and other various additives may be appropriately compounded. Further, in order to manufacture the resin composition for sealing electronic parts of the present invention as a molding material, epoxy resin, phenol resin curing agent, curing accelerator, inorganic filler, silica gel, and other additives are sufficiently mixed with a mixer or the like. After uniform mixing, the mixture is further melt-kneaded with a hot roll or a kneader, and cooled and pulverized to obtain a sealing material.

[0009]

The present invention will be described below by way of examples. The mixing ratio is shown in parts by weight. << Example 1 >> 90 parts by weight of biphenyl type epoxy resin (Yuka 4000, epoxy equivalent 190, melting point 107 ° C.) 8 parts by weight of brominated epoxy resin (Epiclon 152, Dainippon Ink and Chemicals, Inc.) Epoxy equivalent 360, softening point 65 ° C) Phenol novolak resin 52 parts by weight (Sumitomo Durez Co., Ltd .: hydroxyl equivalent 105, softening point 70 ° C) Silica gel A 15 parts by weight (maximum particle diameter 200 μm, average particle diameter 20 μm, average)・ Pore volume 5 ml / g) ・ Crushed fused silica 100 parts by weight (average particle size 15 μm, maximum particle size 100 μm) ・ Spherical fused silica 500 parts by weight (average particle size 23 μm, maximum particle size 75 μm) ・ γ-glycidoxypropyl 6 parts by weight of trimethoxysilane (Nippon Unicar Co., Ltd.) 1 part by weight of 2-methylimidazole (Shikoku Chemicals Co., Ltd. 2MZ) Antimony trioxide 8 parts by weight ・ Hoechst wax S 3 parts by weight ・ Carbon black 2 parts by weight are sufficiently mixed at room temperature, then kneaded at 80 to 110 ° C. using a biaxial heat roll, cooled, pulverized, and sealed for electronic parts. A resin composition for stopping was obtained.

Examples 2 and 3 A resin composition for sealing electronic parts was obtained in the same manner as in Example 1 with the composition shown in Table 1. As the epoxy resin of Example 2, a cresol novolak type epoxy resin (Sumitomo Chemical Co., Ltd .: epoxy equivalent: 200, softening point: 60 ° C.) was used. << Comparative Examples 1 to 5 >> Resin compositions for encapsulating electronic components were obtained in the same manner as in Example 1 with the formulations shown in Table 1. Using a transfer molding machine, the resin compositions obtained in Examples and Comparative Examples were heated at a temperature of 175 ° C. and an injection pressure of 120 kg / c.
After molding at m ² , post-curing treatment was performed at 175 ° C. for 8 hours to obtain a test piece. The silica gel used in the comparative example is as follows.・ Silica gel B: maximum particle size 30 μm, average particle size 2 μm,
Average pore volume 10 ml / g • Silica gel C: maximum particle size 150 μm, average particle size 25 μ
m, average pore volume 0.01 ml / g ・ Silica gel D: maximum particle size 100 μm, average particle size 8 μm
m, average pore volume 90 ml / g

<< Evaluation method >> Spiral flow (fluidity): Using a mold conforming to EMMI-I-66, 175 ° C., injection pressure 70 kg / cm ^2.
Was measured. Moisture absorption: A disk having a thickness of 50 mm and a thickness of 3 mm was molded, treated in a thermo-hygrostat at 85 ° C. and a relative humidity of 85% for 336 hours, cooled to a room temperature in a desiccator, and then measured for the rate of weight increase. Moisture trapping property: The resin composition was previously molded at 175 ° C. to obtain a molded plate having a diameter of 50 mm and a thickness of 1 mm, and the molded plate was sealed with an adhesive on the upper part of a concave glass container containing phosphorus pentoxide. 100 in a thermo-hygrostat at 85 ° C and 85% relative humidity
After standing for 300 hours for 300 hours, the weight increase rate of phosphorus pentoxide inside was measured. Evaluation ：: Less than 0.1% by weight, ×: 0.1% by weight or more Dimensional stability: A disk having a thickness of 50 mm 3 mm was formed, and
The surface smoothness of the molded product after the treatment in a thermo-hygrostat at 85 ° C. and a relative humidity of 85% for 336 hours was visually observed and judged with a microscope of 50 times magnification. Table 1 shows the evaluation results.

[0012]

[Table 1]

[0013]

EFFECT OF THE INVENTION By using the resin composition of the present invention, the dimensional stability is excellent, the infiltration of moisture from the outside can be prevented,
It is particularly suitable for electronic parts with windows such as solid-state imaging devices.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C08L 63/00-63/10 C08G 59/62 C08K 3/34-3/36 H01L 23/29

Claims (2)

(57) [Claims] An epoxy resin, a phenol resin curing agent,
Hardening accelerator, inorganic filler, silica gel as essential components,
The maximum particle size of the silica gel is 200 μm or less, and the average particle size is 5
４０40 μm, average pore volume is 0.1-50 ml / g,
A resin composition for sealing electronic parts, wherein the content of silica gel in the entire composition is 1 to 30% by weight. 2. The electronic component sealing resin composition according to claim 1, wherein the inorganic filler is silica, and the total amount of silica and silica gel is 65 to 90% by weight of the total composition.