IC Component Level Failure Induced By Intermetallic Layer Structural Defects of Solder Joint

Abstract

ABSTRACTSolder joint has been widely used in microelectronics industry as an interconnect of Integrated Circuit (IC) chip and Printed Circuit Board (PCB). Frequently, a functional failure of the component on the system is a result of solder joint damage. Eutectic 63Sn/37Pb solder joint mechanical behaviors on Ni/Au plated copper pad and bare copper pad were experimentally investigated to address the effect of pad surface cleanness on the formation of intermetallic compound. The joints with thinner intermetallic compound layer resulted in a poor solder ball shear strength. Microstructural analysis revealed that the oxidations of Ni and Cu during substrate manufacturing contributed to the improper growth of intermetallic compound during assembly and reliability tests. In additions, the experimental results showed that the growth of the intermetallic compound layer were dependent not only on the time and temperature of solder reflow and testing, but also on the cleanness of the pad surfaces and available area for the diffusion of Ni in the case of Ni/Au plated copper pad, Cu in the case of bare copper pad and Sn in the joint area.