JP2596133B2 - Manufacturing method of epoxy resin molding material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention hardly causes cracks during a cooling / heating cycle,
The present invention relates to an epoxy resin molding material having excellent crack resistance, and particularly to an epoxy resin molding material for encapsulating electronic components such as an LSI having a large element size.

[Conventional technology]

Conventionally, epoxy resin molding materials have been widely used in the field of sealing electronic components such as coils, capacitors, transistors, and ICs. The reason for this is that the epoxy resin is balanced in various properties such as electrical properties, heat resistance, mechanical strength, and adhesiveness to an insert product.

[Problems to be solved by the invention]

Epoxy resin has the above-mentioned features, but on the other hand, it has a hard and brittle property that is a disadvantage of thermosetting resin,
There is a problem in terms of impact resistance and thermal shock resistance.

Electronic component packages are small, as represented by ICs.
It tends to be thinner, which causes a problem that the package cracks during a thermal cycle. Cracks generated in this package facilitate moisture penetration and cause corrosion of the insert. When molding electronic components with small and thin packages and large insert products, various problems occur with conventional epoxy resin molding materials. There is a strong demand for a material that is less likely to crack. As a remedy, there is a method of modifying an epoxy resin system with a silicone polymer. However, although the silicone polymer is incompatible with the epoxy resin, the thermal shock resistance of the molding material is improved, but it exudes at the time of molding, burrs (extrudes from the mold clearance) and the appearance of the molded product deteriorates. Easy to cause.

The present invention modifies the hard and brittle properties of an epoxy resin with a specific thermoplastic elastomer to obtain a molding material having excellent crack resistance and moldability.

[Means for solving the problem]

The epoxy resin molding material for sealing electronic parts of the present invention comprises: (A) an epoxy resin having two or more epoxy groups in one molecule; (B) a compound having two or more phenolic hydroxyl groups in one molecule; (C) It is characterized by containing a copolymer of polybutylene terephthalate and polytetramethylene ether glycol as an essential component, thereby significantly improving the package crack resistance of an actual FP (flat package) type IC. it can.

The epoxy resin having two or more epoxy groups in one molecule of the component (A) used in the present invention includes:
There is no limitation as long as it is a commonly used epoxy resin molding material for electronic component encapsulation, and phenolic novolak resin such as phenol novolak type epoxy resin and orthocresol novolak type epoxy resin are epoxidized. Diglycidyl ethers such as bisphenol A, bisphenol B, bisphenol F and bisphenol S, phthalic acid, glycidyl ester type epoxy resins obtained by the reaction of polychlorinated acids such as dimer acid with epichlorohydrin, diaminodiphenylmethane, isocyanuric acid, etc. Glycidylamine type epoxy resin obtained by the reaction of polyamine and epichlorohydrin, linear aliphatic epoxy resin obtained by oxidizing olefin bond with peracid such as peracetic acid, and alicyclic epoxy resin There are, can be used in combination even these at an appropriate number of types.

In one molecule of the component (B) used in the present invention, 2
As a compound having two or more phenolic hydroxyl groups,
Phenol, cresol, xylenol, resorcinol,
Novolak-type phenol resins obtained by subjecting phenols such as catechol, bisphenol A, bisphenol F and formaldehyde to a condensation reaction in the presence of an acidic catalyst, bisphenol A, bisphenol F, polyparavinylphenol resin, resorcinol, catechol, hydroquinone, etc. There are trivalent phenols and the like, and they may be used alone or in combination of two or more. Further, the equivalent ratio with the epoxy resin (A) (the number of hydroxyl groups in (B) / the number of epoxy groups in (A)) is as follows:
Although not particularly limited, 0.5 to 1.5 is preferable.

Further, a curing accelerator that promotes a curing reaction between the epoxy resin and the compound having a phenolic hydroxyl group can be used. Examples of the curing accelerator include tertiary amines such as triethylenediamine, benzyldimethylamine, triethanolamine, dimethylaminoethanol, and tris (dimethylaminomethyl) phenol, 2-methylimidazole, 2-phenylimidazole, Imidazoles such as phenyl-4-methylimidazole and 2-heptadecylimidazole; organic phosphines such as tributylphosphine, methyldiphenylphosphine, triphenylphosphine, diphenylphosphine and phenylphosphine; tetraphenylphosphonium tetraphenylborate; triphenylphosphine・ Tetraphenylborate, 2-ethyl-4-methylimidazole ・ Tetraphenylborate, N-methylmorpholine ・ Tetraphenylborate What tetraphenyl boron salts and the like. Further, as a filler, crystalline silica, fused silica, alumina, zircon, calcium silicate, calcium carbonate, silicon carbide, silicon nitride, boron nitride, beryllia,
Magnesia, zirconia, zircon, fosterite,
One or more kinds of powders such as steatite, spinel, mullite and titania, or spherical beads of these can be used. The amount of the filler is preferably 40 to 75% by volume, but is not particularly limited.

Other additives include higher fatty acids, higher fatty acid metal salts, release agents such as ester waxes, coloring agents such as carbon black, epoxy silane, amino silane, ureido silane, vinyl silane, alkyl silane, organic titanate, aluminum alcoholate, etc. Coupling agents and flame retardants can be used.

The present invention is characterized in that the epoxy resin composition is modified with the component (C), that is, a copolymer of polybutylene terephthalate and polytetramethylene ether glycol. The degree of polymerization and the copolymerization ratio of the copolymer of component (C), polybutylene terephthalate and polytetramethylene ether glycol, are not particularly limited, but the molecular weight of polybutylene terephthalate is several hundred to several thousand, and A block copolymer having a molecular weight of methylene ether glycol of about 1,000 to 3,000 and a total molecular weight of tens of thousands is preferable. Further, the ratio of the polybutylene terephthalate of the hard segment to the polytetramethylene ether glycol of the soft segment is preferably 30 to 70% by weight of the soft segment. ~ 70
% Is preferred. As the quantitative ratio of the components (A), (B) and (C), the ratio of the component (C) to the transmission of the components (A) and (B) is set to 0.02 to 0.35. When the ratio of the component (C) is less than 0.02, the effect on impact resistance is small,
If it exceeds 35, the heat resistance becomes poor. Furthermore, in using the component (C), it is necessary to previously melt and mix the component (C) uniformly with the epoxy resin (A) and the phenol compound (B) in order to enhance the dispersibility and the effect on crack resistance. is there. Here, “uniform” means a visually transparent state. Melt mixing conditions include:
Although not particularly limited, it is desirable that the epoxy resin (A) and the phenol compound (B) are melted and the reaction is not accelerated in the absence of a catalyst. Therefore, the softening point of (A) or (B) is desirably in the range of 20 ° C or higher to 170 ° C or lower. Since the base epoxy resin and the component (C) cannot be mixed uniformly in a usual molding material manufacturing process, that is, a kneading process using a roll, an extruder, or the like, a melt-mixing process is required in advance as described above. Thereafter, the resulting modified resin and additives such as a filler, a curing accelerator, and a filler are added, and the mixture is further kneaded to obtain a molding material.

[Action]

The cause of the package crack generated during the cooling / heating cycle is due to the thermal stress generated between the insert product and the molding compound for sealing due to a temperature difference.

The thermoplastic elastomer as the component (C) modifies the hard and brittle properties of the molding compound for encapsulation and imparts flexibility to the material, thereby improving the package crack resistance.
Further, when the thermoplastic elastomer is mixed and used in advance in the resin, the dispersibility of the thermoplastic elastomer is improved, and the material becomes uniform, so that the package crack resistance is further improved. Further, as an effect obtained by melting, the component (C) does not exude at the time of molding and does not deteriorate the moldability.

On the other hand, the thermal stress generated during the cooling and heating cycle can be reduced by modifying the epoxy resin with a thermoplastic elastomer to reduce the elastic modulus of the molding material. It is also considered that the thermal shock resistance was improved.

〔Example〕

Hereinafter, the present invention will be described with reference to examples, but the scope of the present invention is not limited to these examples.

Perprene P-40H (Polyester Elastomer, manufactured by Toyobo Co., Ltd.) based on 100 parts by weight of a cresol novolak type epoxy resin having an epoxy equivalent of 220 and a softening point of 78 ° C., and 48.2 parts by weight of a phenol novolak resin having a hydroxyl equivalent of 106 and a softening point of 83 ° C. Name) 10 parts by weight, 20 parts by weight, and 30 parts by weight of a melt-blended resin were prepared. The resin was prepared by stirring at 150 ° C. for 60 minutes without solvent. All of the obtained resins were yellow to orange and transparent and uniform. To these resin systems, triphenylphosphine (1 part by weight), carnauba wax (2 parts by weight), carbon black (1 part by weight), γ-glycidoxypropyltrimethoxysilane (2 parts by weight), quartz glass powder (70 parts by weight) % By weight)
Kneading temperature 80 ~ 90 ℃, using inch diameter heating roll,
The epoxy resin molding materials of Examples (1) to (3) were prepared under the conditions of a kneading time of 7 to 10 minutes. Also, as a comparison, 10 parts by weight of perprene P-40H pulverized to 100 μm or less was blended without melting and mixing, and the other example was prepared in the same manner as in the example, and molding without perprene P-40H was added. The material was produced as Comparative Example (2).

In order to clarify the effect of the present invention, the results of a thermal shock test of an FP (flat package) type IC are shown. The size of the FP used in this evaluation was 19 × 14 × 2.0 t (mm) and 6 × 6 (m
This is a 54-pin, 42-alloy lead with the element of m). The test conditions were soaking for 2 minutes each in silicone oil at 150 ° C. and liquid nitrogen at −196 ° C., and the cycle was one cycle. The evaluation was performed by observing the appearance with a microscope and determining whether or not there was a package crack. The FP molding is 180
° C., 90 seconds and in the conditions of 70kgf / cm ^2, 180 ℃ after molding was cured after 5 hours.

 Table 1 shows the results of the thermal shock test.

As shown in Examples (1) to (3) from Table 1, the package crack resistance is greatly improved by using a thermoplastic polyester elastomer, Perprene P-40H, which is mixed and melted in advance with an epoxy resin and a phenol novolak resin. it can. Further, the effect increases with the addition amount of P-40H. Furthermore, when the comparative example (1) and the example (1) are compared, the effect of melt mixing in advance is clear.

〔The invention's effect〕

The epoxy resin molding material obtained by the present invention can greatly improve crack resistance as compared with the conventional one. In the field of electronic components, especially in ICs such as FP (flat package) and SOP (small outline package), packages are becoming thinner and smaller, and package crack resistance is strongly required in conjunction with the increase in size of elements. It can be widely applied to these products, and its industrial value is great.

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Claims (1)

(57) [Claims] (A) an epoxy resin having two or more epoxy groups in one molecule; (B) a compound having two or more phenolic hydroxyl groups in one molecule; and (C) polybutylene terephthalate and polytetraethylene. A copolymer of methylene ether glycol as an essential component, (A), (B) and (C) are previously melt-mixed uniformly at a ratio of (C) / ((A) + (B)) of 0.02 to 0.35, Thereafter, a kneading process is performed by adding a filler, a curing accelerator, and the like, and a method for producing an epoxy resin molding material.