Reliability study on polymer/inorganic interface in microelectronic packaging

Abstract

Flip chip technology has been increasingly used in electronics packaging and considerable effort has been made in the recent years to increase the reliability of the solder joints. It has been well established that underfill can be introduced to improve lifetime of solder joints in flip chip structures. However, due to considerable coefficient of thermal expansion (CTE) mismatch between the underfill and its adjacent materials such as silicon wafer and FR-4 composite, delamination at the interface of the adjacent layers becomes a new reliability problem. The CTE mismatch and manufacturing defects between underfill and its adjacent materials may induce severe interfacial delamination during temperature variation or in the presence of moisture. The present project, therefore, aimed to study the delamination behaviour using either temperature cycling test or hygrothermal loading.