Aluminium oxide thickness impact on wire bond shear

The extensive usage of electronics devices in automotive applications, where high reliability and long life is required making wire bond shear test a mandatory. Tremendous progress has been made to improve the quality and reliability of the semiconductor chip. However, the quality of interconnect seems to have been overlooked and lagged behind than other processes. Internal outgoing inspection on bond pads triggered this study of wire bonding to ensure our reliability before shipping to customer. This experiment mainly focuses on stained pads and metal grain on polyimide module. The introduction of Oxygen Plasma step before polyimide coating was carried out to mitigate the occurrence of stained pad phenomenon. In this paper, we discuss mainly on the impact of Oxygen plasma to aluminium oxide thickness and wire bonding reliability. TEM data indicates that the oxide thickness is acceptable and wire bond shear results will also be shown.