Residual Stresses and Cracking in Metal/Ceramic Systems for Microelectronics Packaging

Abstract

Residual stresses that develop in a metal/ceramic system due to thermal expansion mismatch were calculated for a work‐hardening metal. The calculations were conducted for a cylindrical configuration, pertinent to certain microelectronics packaging systems. Experimental measurements of the stress have also been made on a Cu/cordierite ceramic system, using an indentation technique. It is shown that porosity in the metal can plastically expand and provide a mode of dilatational relaxation. Porosity in the metal thus emerges as an important stress‐relaxing mechanism.