A new multichip module using a copper polyimide multilayer substrate

A multichip module using a multilayer substrate with a polyimide dielectric and a fine pattern of copper conductors is discussed. This substrate contains small copper columnar vias, which reduce the thermal resistance of the polyimide layers without causing a channel accommodation drop, and thin-film resistors for terminated transmission. The module can mount a high density of high-speed LSI chips that produce twice as much heat as those in conventional modules and can transmit high-speed pulses at over 2 Gb/s. The structure and features of the module, its design and fabrication, and its electrical and thermal characteristics are discussed. >