ADVANCED CERAMIC SUBSTRATES FOR MULTICHIP MODULES WITH MULTILEVEL THIN-FILM INTERCONNECTS

A number of substrate options are available for multichip modules which use low dielectric constant polymers and thin films to form high density interconnects. Ceramic, cofired ceramic, silicon, metal, and ceramic metal composite substrates have all been used [1]-[3]. Each has its own combination of advantages and disadvantages with respect to thermal conductivity; coefficient of thermal expansion; surface finish and flatness; strength; ability to incorporate passive components; and ability to form an integrated package. Cofired 99.6% alumina/tungsten and aluminum nitride materials systems have been developed which offer significant advantages for use as multichip module bases. The materials properties, process capabilities, and application guidelines for these two systems are described herein.