Thermal-Mechanical behavior of highly (111)-oriented Nano Twinned Electroplated copper for advanced electronic packaging

Abstract

This study investigates the thermal-mechanical behavior of 3μm thick, highly (111)-oriented Nano-Twinned (NT) electroplated copper films. The research focuses on understanding the temperature-dependent elastoplastic behavior of NT copper under thermal loading, using in-situ curvature measurements during thermal cycling experiments, with temperatures ranging from RT to 420°C. The results are benchmarked against classical copper films. The study reveals that NT copper exhibits a larger stress relaxation at high temperatures, and higher mechanical strength compared to classical copper. Additionally, the microstructural analysis shows that NT copper maintains its (111) orientated columnar grain structure and demonstrates considerable thermal stability after multiple thermal cycles. These findings highlight the potential of NT copper for high-performance electronic packaging technologies.