Reliability evaluation of polymer coated mu-chip multi-level microelectric assemblies

The purpose of this program was to consider reliability factors relating to polymer coated, beam lead chip, hybrid microcircuits fabricated on substrates with multi-level conductors. Such assemblies were considered as a means to reduce the cost and volume of conventional electronic subsystems using discrete microcircuits in hermetic packages. Monolithic large scale integration (LSI) is one potential means of achieving the desired goals, but it involves difficulties in testing, it is not repairable, and it becomes economical only in large production volumes. Hybrids permit using less complex circuit chips produced with high yield and at lower cost than LSI circuits. Such hybrids could be tested during assembly and malfunctioning chips could be replaced before final encapsulation as necessary. Beam lead contacts offer potential economies in contact bonding and improved reliability. Multi-level conductor substrates should provide the interconnection complexity needed to realize the desired electronic functions. The use of silicon nitride over silicon dioxide as the primary passivation on beam lead circuit chips should be given higher reliability as regards surface related failures.