Thermal phenomena during the encapsulation of electronic devices

Abstract

As the complexity of integrated circuit packaging increases, the thermo-mechanical integrity of the package becomes critical because of thermal stresses induced by the fabrication and operating temperature range. A variety of materials with a wide range in thermal expansion coefficients, modulus and crack propagation properties (toughness) are required. The stresses induced in the encapsulation and fabrication processes and subsequent assembly operations are usually larger because of the mismatch in material properties than the stresses during service ambient. Thermomechanical stresses from different materials in the package as related to assembly and testing provide designers with difficult choice of options. Review of thermally-induced failures of encapsulated devices in relation to fabrication and assembly sequences and testing will be discussed for broad product applications.