Study The Mixed-Mode Delamination of The Epoxy/Cu Interface

Abstract

The high density packaging, e.g. stacked die packages et al., includes interfaces between different materials. The device reliability is heavily related to the behavior of the interfaces. For instance, the delamination may propagate along dissimilar material interfaces and lead to electrical failure during the package manufacturing, testing processes and even in working state under severe environmental conditions. The interfaces between the epoxy-based composites and copper may be critical due to the large CTE mismatch of the materials. The interface fracture exhibits mixed-mode that combined with mode-I and model-II fractures. In this work, we designed the sandwich samples and a new apparatus to characterize the interface fracture of the epoxy/Cu interface. The sample can be loaded in different angles. The energy release rate and mode mixity were obtained upon the experimental results by the mixed-mode elastic fracture analysis. The method can be applied for other interface characterization in the packaging.