Research note Irregular effect of chloride impurities on migration failure reliability: contradictions or understandable?

Rigid flex circuits have hislorically been used in military and high-end performance electronic packaging to improve reliability, reduce weight and save space. This type of interconnect olFers higher reliability and a tighter form factor when compared to more conventional interconnect techniques. Improvements in printed circuit fabrication processes and laminate materials have made possible unique opportunities for high density rigid Ilex circuitry. Recently MCM-L or laminate based multi chip modules have been gaining in popularity as a lower cost packaging alternative to traditional MCM-C or ceramic substrate based multi chip modules. This paper describes the steps taken to redesign existing modules from MCM-C technology to MCM-L(F). Several actual products that have been redesigned from ceramic substrate technology lo laminate based packaging using rigid flex as the enabling technology are shown. Data is presented on thermal dissipation, mechanical reliability, electrical performance, and thermal reliability of the laminate substrate as well as assembly information. ʹ.ʹ(ʹ•; 1998 IMAPS.