The study on failure mechanisms of bond pad metal peeling: Part A––Experimental investigation

Abstract

For the experimental investigation on failure mechanisms of bond pad metal peeling, 31 failed SDRAM chips after the pad peeling are gathered, and SEM and FIB are utilized. From the results of this study, the vertical tension loading transferred by the capillary to the deformed ball is recognized as the direct driving force for the pad peeling and the crack on the bonding pad as well as its propagation into the oxide layers under the pad is identified as the direct cause of the pad peeling. Moreover, the propagation of the crack along the interface of the layers under the pad is explained as the initiation of ‘ductile fracture type failure’, which can be considered as a possible cause of the pad peeling. A schematic diagram for the process of the pad peeling is constructed based on the results of this research and the effect of the probe test on the pad peeling is also investigated to confirm the result of Hotchkiss et al. [Proceedings of the 51st Electronic Components and Technology Conference, 2001, p. 1175].