A review of planar techniques for multichip modules

In VLSI and ULSI integrated circuit (IC) fabrication, the problem of planarity is well known, particularly at the intermetallic level. Numerous planarization approaches involving either the materials and/or techniques have been put forward. For multichip module (MCM) fabrication, thin-film multilayer substrates with excellent characteristics have become increasingly essential for miniaturizing and achieving a high level of functionality. Therefore, as for IC fabrication, topography-induced problems increase with increasing integration density. The author reviews various planar techniques which can be used in the fabrication of multilevel interconnects and compares their interest for MCMs