UV-curing and thermal stability of dual curable urethane epoxy adhesives for temporary bonding in 3D multi-chip package process

Multi-chip packages (MCP) refers to a packaging configuration, connected via wirebonds to a multilayer circuit board, and protected by either a molded encapsulant or a low-cost ceramic package. As it requires high processing temperature, the adhesives for MCP need to show proper adhesion and thermal stability at high temperature. This study employed semi-interpenetrated (semi-IPN) structured polymer networks using UV-curing with acrylate terminated dual-curable urethane epoxy adhesive, a dipentaerythritol hexacrylate (DPHA), using hydroxydimethyl acetophenone as photo-initiator. UV-curing and thermal stability focused on different photo-initiator contents were investigated using photo-DSC, FTIR-ATR spectroscopy, gel content and TGA. The results show that UV-curable acrylic formulations with different content of photo-initiator affects UV-curing and thermal stability.