Fabrication and packaging of high-density multichip interconnect (HDMI) substrates

A process is described for the fabrication of high-density multichip interconnect (HDMI) substrates based on 6-in. diameter silicon or alumina wafers, a special low-coefficient-of-thermal-expansion polyimide dielectric, and aluminium metallization. Key issues in the assembly and hermetic packaging of large HDMI substrates, including tape-automated bonding interconnection, die attachment, and rework, are discussed. Large 2*4 in. and 4*4 in. aluminum nitride packages are being developed that are compatible with the silicon substrates, have a high thermal conductivity, and can be hermetically sealed.<<ETX>>