Multichip modules: next-generation packages

Multichip modules (MCMs), which interconnect multiple bare dice by means of a stack of conductive and dielectric thin films, are discussed. Among their advantages are reduced delays between chips, simplified power distribution, and enhanced dissipation capabilities. Key design demands that should be weighed by IC design engineers planning to use MCMs are examined. They concern transmission delays, power distribution, heat dissipation, and temperature, as well as testing, burn-in, and rework. The various approaches to MCM packages are described. Factory-programmable versus user-programmable options are considered. Techniques for connecting chips to substrates are discussed