Rjr Polymers, Inc.

Tony B Shaffer

Richard J Ross

John Qiang Ni

K Scott Mellen

Cynthia L Ross

Raymond S Bregante

Semiconductor circuit devices (dies) are incorporated into moisture-impenetrable electronic packages by forming enclosures around the die in three separate parts&mdash;base, sidewalls, and lid. The die is first soldered or otherwise bonded to the base, followed by attachment of the sidewalls to the base, and finally the lid to the sidewalls. For procedures involving a heat-conductive base and a high soldering temperature, the die can be secured to the base at the high soldering temperature, followed by application of the sidewalls to the base at a significantly lower temperature, avoiding potential high-temperature damage to the sidewalls. Plastic sidewalls which would otherwise deteriorate or become distorted upon exposure to the high soldering temperature can thus be used. For electronic packages in general, the use of plastic sidewalls allows the use of combinations of materials for the lid and base that are otherwise incompatible, and reduces or eliminates the incidence of failure due to stress fractures that occur during the high temperatures encountered in fabrication, assembly, testing, or use of the package.

Use of diverse materials in air-cavity packaging of electronic devices

Electronic packages that consist of dies sealed within hollow plastic enclosures with electrically conductive leads penetrating the enclosure walls to access the die circuitry are manufactured by applying a heat-curable adhesive to the leads at only those locations where the surfaces of the leads will interface with the enclosure material, molding the package around the leads, and curing the adhesive during the molding process or during a post-cure. The adhesive is formulated to form a gas-tight seal around the leads and to maintain the seal during the thermal cycling that the components are exposed to during the typical procedures involved in manufacturing the packages and in making the electrical connections to other circuitry, as well as the typical environmental changes that the finished and installed product is exposed to during use. In particular, the adhesive is selected to accommodate differences in the coefficients of thermal expansion between the leads and the enclosure material while still maintaining a vapor-tight seal.

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Alameda, CA, United States of America

Tony B Shaffer