Yield and reliability concerns in polyimide based multi-chip modules

The key technology elements used in the fabrication of a high-performance, low-cost silicon-on-silicon multichip module (MCM) are described. Al/PI multilayer substrates, flip-chip soldering of chips to substrate, and wire bonding of substrate to a ceramic pin grid array (PGA) package were the various interconnection elements used. Some of the yield and reliability issues encountered in the manufacture of the substrates, the flip-chip process, and wire bonding of the Al/PI structures are discussed, and process changes made to solve some of these problems are presented.<>