ABSTRACT
Electronics packaging provides protection for the semiconductor devices, a means of electrically interconnecting those devices with passive and other components, and a path for heat removal. Single chip packaging allows pretesting and screening of the individual devices prior to assembly into the system. However, this approach increases the number of interconnect interfaces between devices, that is, die-to-package, package-to-substrate, substrate-to-package, and package-to-die. PCBs based on polyimide laminates have been used at 225°C–250°C to interconnect single chip packages and passive components. Thick film substrates are fabricated by sequentially screen printing and firing conductor, resistor, and dielectric pastes onto a prefired ceramic substrate to build up the required interconnect and insulating pattern and form resistive elements. Die attach is the joining of the die to the package or substrate, while substrate attach joins the substrate to the package. Plastic packaging commonly used for consumer applications is not appropriate for high-temperature use.
