Low stress anhydride molding compound for RF applications

Anhydride cured epoxy molding compounds offer inherently high glass transition temperature (T/sub g/), high adhesion and low dielectric constant at a moderate cost. However, historical drawbacks of anhydride-cured compounds (poor moldability and moisture resistance, high coefficient of thermal expansion, shrinkage and brittleness) have limited their use for surface mount applications. This paper details the development of new anhydride compounds designed specifically for surface mount power applications.