Reliability of area array pressure contacts on the DTAB package

Demountable tape automated bonding (DTAB) is a VLSI package, developed and qualified for high performance (≫100 MHz), high pincount (>400) ASICS with high power dissipation (~40 W). Extensive reliability testing has been used to optimize the design as well as to qualify the package for product applications. The formal tests have been extended beyond the industry standards to include system level tests, designed to stress the pressure contact under conditions not expected from other equivalent packages. Testing reveals that this package produces very high reliability "sealed" contacts, although thin gold of 5-μ-in thickness is used instead of the thick 50-μ-in thickness conventionally required by other applications. The test and testing methodology are discussed, the results and the failure modes and analysis are presented. The design changes and materials used to eliminate the failures are described