Stresses in Thin Polymeric Films: Relevance to Adhesion and Fracture

Abstract

The problems of delamination and cracking in microelectronic structures are considered from a unified point of view, i.e., in terms of the stresses built up in the structure due to manufacturing processes and end use conditions. We take the position that delamination and cracking are simply different aspects of a larger problem, which is concerned with the thermal-mechanical stability of the structure. From this vantage point it is equally important to understand the bulk mechanical and thermodynamic properties of the materials used in the structure as well as the detailed properties of the various interfaces. These ideas are illustrated in detail for a simple via structure, which is subjected to thermal expansion mismatch stresses. Detailed finite element calculations of the relevant stress distributions are presented. The relevance of bulk mechanical properties on stresses affecting adhesion at interfaces is emphasized throughout.