JPH08109311A - Resin composition for semiconductor sealing - Google Patents

Abstract

PURPOSE: To produce a resin composition for semiconductor sealing stably storage at normal temperature, having excellent reliability and flame-retardancy after the soldering treatment in the surface mounting of a semiconductor pack age and enabling effective utilization of resources by adding a crushed waste such as cull and runner as a filler to a resol-type phenolic resin. CONSTITUTION: This resin composition contains (A) a resol-type phenolic resin, (B) a cure accelerator, (C) an inorganic filler and (D) a crushed product of a hardened material of a resin composition for semiconductor sealing having a particle diameter distribution of 0.01-150μm and an average particle diameter of 5-20μm (preferably 0.5-25wt.% based on the total composition) as essential components. The component A is e.g. a resin expressed by formula, the component B is 1,8-diazabicycloundecene, etc., and the component C is e.g. fused silica powder having an average particle diameter of 10-20μm and maximum particle diameter of 70-150μm.

Description

Detailed Description of the Invention

[0001]

The present invention makes effective use of waste,
The present invention relates to a resin composition for semiconductor encapsulation, which has excellent room-temperature storability, moldability, solder heat resistance, moisture resistance reliability, and flame retardancy.

[0002]

2. Description of the Related Art As a resin component of a resin composition for semiconductor encapsulation such as transistors, capacitors, diodes, ICs, LSIs, a combination of epoxy resin and phenol resin curing agent is a resin suitable for moldability, reliability and mass productivity. Has been adopted as. However, in recent market trends of miniaturization, weight reduction, and high performance of electronic devices, there is an increasing demand for contributions to resource reuse and environmental problems. Are becoming more and more demanding. Therefore, there are problems that cannot be solved by conventional resin compositions.

The first problem is that the surface mounting of a semiconductor package causes the package to be rapidly exposed to a high temperature of 200 ° C. or higher during solder dipping or a reflow process, which may cause the package to crack or seal the chip and the chip. There is a problem of solder heat resistance that interface separation from the resin occurs and moisture resistance decreases. Regarding the improvement of solder heat resistance, use of heat-resistant epoxy resin, use of flexible resin for stress reduction during solder immersion and improvement of adhesion to lead frames and chips, addition of adhesion-imparting components, thermal expansion Many proposals have been made such as increasing the amount of the inorganic filler compounded to reduce the coefficient or improving the treatment conditions of the silane coupling agent on the silica surface. However, the fundamental drawback is that epoxy resin has low heat resistance,
In the above environment, the physical durability suddenly decreases,
It is impossible to maintain the strength that can withstand thermal stress. The effects of the above proposals cannot be sufficiently obtained unless the reduction in heat resistance is improved. Although the use of an epoxy resin having a special skeleton structure is improving properties considerably, the price is high and the application is naturally limited to high value-added products. The second problem is the increase in total production cost. The use of special raw materials inevitably raises the price of raw materials, and storage conditions often require very strict conditions such as cryogenic storage. The third problem is the presence of brominated epoxies, antimony, etc. from the viewpoint of environmental hygiene, and the epoxy resin cannot inherently have flame retardancy that can be used without blending these flame retardants. The fourth problem is that in terms of effective use of resources, as long as the current semiconductor encapsulant uses a thermosetting resin, there is currently a method other than discarding for the treatment of molded articles such as culls and runners. That is not the case.

[0004]

As a result of various studies on effective use of resources of a resin composition for encapsulating a semiconductor, storability at room temperature, solder heat resistance, flame retardancy, etc., The resin component is a resol-type phenol resin, and cal,
The present invention has been completed by using a crushed product of waste such as a runner as a filler.

[0005]

The present invention provides a resin composition for semiconductor encapsulation having a resol type phenol resin, a curing accelerator, an inorganic filler and a particle size distribution of 0.01 to 150 μm and an average particle size of 5 to 20 μm. It is a resin composition for semiconductor encapsulation which has a crushed product of cured product as an essential component, without using flame retardant such as brominated epoxy or antimony in addition to effective use of resources, storage at room temperature and solder heat resistance. It has excellent flame retardancy.

The present invention will be described in detail below. The resol type phenol resin used in the present invention is obtained by a dehydration condensation reaction of phenols with formaldehyde, an aldehyde source such as paraform, and has a phenolic hydroxyl group, a methylol group, a dimethylene ether group, a monomer,
A mixture containing an oligomer and a polymer and having a softening point (balling method) of 50 to 80 ° C. is preferable in terms of workability and the like. An important point of the present invention is to use a resol type phenol resin as a resin component. By using this resol type phenol resin, low pressure molding is possible and it has high fluidity, room temperature storage property, solder heat resistance,
It is possible to obtain a semiconductor sealing material having excellent flame retardancy and the like.
In addition, when a crushed product of a cured product such as cull or runner generated when a semiconductor is encapsulated as a filler is used together with a resol-type phenol resin, the crushed product of the cured product becomes an epoxy resin-based semiconductor encapsulating resin composition. Compared with the case of using, there is an advantage that a large amount can be mixed. That is, when the crushed product of the cured product is used for the epoxy resin-based semiconductor encapsulating resin composition, the curability is hindered by the phosphoric acid contained in the cured product. On the other hand, when used in a resol-type phenolic resin composition, phosphoric acid contained in the cured product does not hinder the curability, so a larger amount of the cured product crushed product than the epoxy resin-based semiconductor encapsulating resin composition is used. It can be blended and effective use of resources becomes possible.

The raw material of the cured product of the resin composition for semiconductor encapsulation, which is the crushed product of the present invention, is not particularly limited, but is mainly composed of cull, runner, etc. generated at the time of encapsulating and molding a semiconductor. . In addition to the epoxy resin-based semiconductor encapsulating resin composition that is currently the mainstream, resol-type phenol resin-based semiconductor encapsulating resin composition, allyl resin-based semiconductor encapsulating resin composition, vinyl resin-based semiconductor encapsulating resin composition The resin composition for semiconductor encapsulation, the resin composition for semiconductor encapsulation according to the present invention, and the like. These may be used alone or as a mixture, but the particle size distribution is from 0.01 to 15
It is essential that the average particle size is 0 μm and the average particle size is 5 to 20 μm. If it is less than 0.01 μm, the fluidity is lowered, and molding defects such as unfilling occur during molding. 150μ
If it exceeds m, large-sized particles are clogged in the gate portion, thin portion, etc. of the molded product, resulting in non-filling. The average particle size is 5 μm
If it is less than 20 μm, the fluidity is lowered, and if it exceeds 20 μm, burrs are likely to be formed on the molded product. The inorganic filler used in the present invention is the same as that used in the epoxy resin composition for semiconductor encapsulation, having an average particle size of 10 to 20 μm and a maximum particle size of 70.
Examples thereof include fused silica powder, crystalline silica powder, alumina, and silicon nitride having a particle size of 150 μm. Particularly in the case of a compound having a large amount of filler, spherical fused silica is generally used.
From the viewpoint of balance between moldability and reliability, it is preferable that the amount of the filler, which is a pulverized product of the cured product of the inorganic filler and the resin composition for semiconductor encapsulation, be 65 to 85% by weight in the total resin composition. . In addition, the compounding amount of this pulverized product is 25% by weight in maximum in the whole composition, and if it exceeds 25% by weight, the fluidity is lowered.

The curing accelerator used in the present invention serves as a catalyst for the cross-linking reaction of the resol type phenolic resin, and specifically, amine compounds such as hexamine, aniline and 1,8-diazabicycloundecene, Examples thereof include imidazole compounds such as 2-methylimidazole, acids such as p-toluenesulfonic acid, alkali compounds such as calcium hydroxide and magnesium hydroxide, and the present invention is not limited thereto, but preferably 1 , 8-diazabicycloundecene, 2-methylimidazole and other imidazole compounds. Further, these curing accelerators may be used alone or as a mixture. The resin composition of the present invention contains a resol type phenol resin, a curing accelerator, an inorganic filler and a crushed product of a cured product of a resin composition for semiconductor encapsulation as essential components. Various coupling agents typified by ring agents, colorants typified by carbon black, release agents such as natural wax and synthetic wax, silicone oil, silicone rubber,
A low-stress additive such as synthetic rubber may be appropriately mixed. In forming a molding material, all the components are heated and kneaded with a heating kneader or a heating roll, followed by cooling and pulverizing to obtain the target epoxy resin composition for semiconductor encapsulation.

The present invention will be specifically described below with reference to examples. Example 1 Resol type phenol resin represented by the formula (1) (softening point 60 ° C.) 25.00 parts by weight

[0010]

Embedded image (L = 1.1, m = 3.2, n = 1.5, p = 2.2)

Fused silica powder 63.40 parts by weight Hardened product crushed product 1 of resin composition for semiconductor encapsulation (hardened product crushed product containing epoxy resin of 70% by weight of inorganic filler, average particle diameter 12 μm, particle size distribution 0 1 to 120 μm) 10.00 parts by weight 1,8-diazabicycloundecene 0.30 parts by weight γ-aminopropyltriethoxysilane 0.50 parts by weight carnauba wax 0.50 parts by weight carbon black 0.30 parts by weight

After mixing the above components with a mixer, the mixture was heated and kneaded with a kneader and a roll at a barrel temperature of 100 ° C., further cooled and pulverized to obtain a resol type phenol resin composition. Using this resin composition, spiral flow, gelling time, glass transition temperature, package air vent burr, bending strength, and flame retardancy were measured. Furthermore, solder cracking property and moisture resistance reliability were evaluated. All sample molding is transfer molding, mold temperature 175 ℃,
Curing was carried out for 120 seconds, and post-curing was carried out at 175 ° C. for 8 hours.

Spiral flow: The length of resin flow in the mold when it is cured for 120 seconds at a transfer molding temperature of 175 ° C. and an effective pressure of 70 kgf / cm ² using a mold conforming to EMMI-I-66. Measured after initial storage and at room temperature for 10 days. Gelation time: A time period in which 2 g of the resin is placed on a hot plate at 175 ° C., spread using a spatula to a size of about 25 mm square and rubbed on the hot plate, and then the resin is cured and peeled off from the hot plate.
Measured after initial storage and at room temperature for 10 days. Glass transition temperature: measured by the TMA method. Package air vent burr: A 16 pDIP package is molded and the burr length of the air vent (15 μm) is measured. Bending strength: Measured at 240 ° C. according to JIS-K6911. Flame retardance: UL94 vertical method. Uses a 1.0 mm thick test piece. Number of solder cracks: 80 pQFP package (package size 14 × 20 mm, thickness 1.5 mm, chip size 9 × 9 mm) is molded and 168 ° C. at 175 ° C. and 85 ° C. and 85% RH after post-curing for 8 hours. It was left for a period of time and then immersed in a solder bath at 260 ° C. for 10 seconds. The packages were observed with a microscope, and the number of external cracks (the number of cracked packages / the total number of packages) was expressed by the number of cracks. Moisture resistance reliability: Molded 80p QFP package, 175
After post-curing at 8 ° C. for 8 hours, it was left in an environment of 85 ° C. and 85% RH for 24 hours, and then immersed in a solder bath at 260 ° C. for 10 seconds. Next, this package was subjected to PCT treatment at 125 ° C. and 2.3 atm, and the PCT treatment time until the defect rate became 50% was expressed as moisture resistance reliability. The evaluation results are shown in Table 1.

Examples 2 to 4 According to the formulations shown in Table 1, a sealing material was obtained in the same manner as in Example 1. Table 1 shows the evaluation results. Comparative Examples 1 to 4 According to the formulations in Table 2, the encapsulating material was obtained in the same manner as in Example 1. The cured product pulverized product 2 of the resin composition for semiconductor encapsulation is an epoxy resin-based cured product pulverized product containing 70% by weight of an inorganic filler and having an average particle size of 3 μm and a particle size distribution of 0.005 to 80 μm. The crushed product 3 of the resin composition for epoxy resin is a crushed product of an epoxy resin system containing 70% by weight of an inorganic filler, having an average particle size of 30 μm and a particle size distribution of 0.10 to 200 μm.
The property of m was used. Table 2 shows the evaluation results.

[0015]

[Table 1]

[0016]

[Table 2]

[0017]

EFFECTS OF THE INVENTION According to the present invention, it has excellent room-temperature storability, reliability after soldering process in surface mounting of semiconductor package, contributes to effective use of resources, and adds flame retardant such as brominated epoxy or antimony. It has excellent flame retardancy without

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Claims (2)

[Claims] 1. A resole-type phenol resin, a curing accelerator, an inorganic filler, and a particle size distribution of 0.01 to 150 μm.
A resin composition for semiconductor encapsulation, comprising a crushed product of a cured resin composition for semiconductor encapsulation having an average particle diameter of 5 to 20 μm as an essential component. 2. The resin composition for semiconductor encapsulation according to claim 1, wherein the content of the crushed product of the cured product in all the compositions is 0.5 to 25% by weight.