Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Patent
1997-02-26
1998-12-29
Gulakowski, Randy
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
523443, 525523, C08L 6300
Patent
active
058543163
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to an epoxy resin composition to seal semiconductor devices, a process for producing it, and a semiconductor device sealed with it, said epoxy resin composition being superior in flame retardance, solder heat resistance, and reliability at high temperatures.
BACKGROUND ART
The sealing of semiconductor devices and other electronic parts usually employs a sealing resin composition composed of epoxy resin, hardener, and inorganic filler because of its low price, high manufacturing efficiency, and balanced properties. Demand for sealing resin compositions has become more stringent than before in accordance with recent thin, dense semiconductor devices which need good solder heat resistance and reliability at high temperatures.
For the sake of safety, semiconductor devices and other electronic parts are required to possess flame retardance conforming to the UL standard. For this reason, it has been common practice to incorporate sealing resin compositions with a flame retard ant (such as brominated epoxy resin and other halogenated polymers) and a flame retarding auxiliary (such as antimony trioxide and other antinomy compounds).
Recent environmental issues have turned public attention to a variety of compounds used as a flame retardant in resin compositions to seal semiconductor devices. It has been pointed out that flame retardants based on a halogenated polymer give off a halogenated gas at the time of their combustion. In addition, it is considered that flame retardants in a hot environment give off a halogenated gas which gradually corrodes the wiring of semiconductor devices to reduce their reliability. Moreover, flame-retarded sealing resin compositions pose a problem with waste disposal if the flame retardant contains an antimony compound. Therefore, it is desirable to minimize the amount of halogenated polymer and antimony compound.
There are substitutes for halogenated polymer and antimony oxide mentioned above. They are hydroxide- and phosphorus-based flame retardants (such as aluminum hydroxide and phosphate ester) disclosed in Japanese Patent Laid-open No. 240314/1987. Unfortunately, they need to be incorporated into sealing resin compositions in large quantities for good flame retardance. The result is deteriorated resin performance and poor molding appearance due to their decomposition and foaming that occur during molding. These disadvantages limit their use to special areas.
The present invention is characterized by incorporating the epoxy resin composition with alumina in a specific amount as part of an inorganic filler. The idea of incorporating an epoxy resin composition with alumina as part of inorganic filler is disclosed in Japanese Patent Laid-open Nos. 70446/1985 and 183915/1985. Alumina in such use is intended for heat dissipation from semiconductor devices. Nothing is mentioned in the disclosures about the use of alumina as a flame retardant.
In view of the foregoing, the present invention was completed to fulfill the following objects. good flame retardance after curing. without voids when used to seal semiconductor devices. immune to cracking when the sealed semiconductor devices are soldered at high temperatures. which permits the sealed semiconductor devices to retain their performance during storage at high temperatures.
DISCLOSURE OF THE INVENTION
The above-mentioned objects are achieved by an epoxy resin composition composed of an epoxy resin (A), a hardener (B), and an inorganic filler (C), characterized in that the content of the inorganic filler (C) is 70-97 wt % and the inorganic filler (C) contains 0.1-50 wt % of alumina.
According to a preferred embodiment, the epoxy resin composition is characterized in that the content of the inorganic filler (C) is 70-97 wt % and the inorganic filler (C) contains 0.1-20 wt % of alumina.
According to another preferred embodiment, the epoxy resin composition is characterized in that the content of the inorganic filler (C) is 87-97 wt % and the inorganic filler (C) contains 0.1-50 wt %
REFERENCES:
patent: 5056214 (1991-10-01), Holt
patent: 5362775 (1994-11-01), Shintai et al.
patent: 5552459 (1996-09-01), Baumann et al.
Hawley's Condensed Chemical Dictionary, pp. 47 and 1034, 12th edition, 1993 .
Sawamura Yasushi
Shimizu Ken
Tanaka Masayuki
Gulakowski Randy
Miller Austin R.
Toray Industries Inc.
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