Capability Evaluation Models for Larger-the-better Type Process on the Assembly and Packaging of IC-manufacturing Industry

Abstract

For years the passive components industry plays a vital role in the development of the electronic industry and economy in our country. Among the assembly and packaging manufacturing processes, wire bonding is the critical process. If the quality of the wire bonding is poor, mal-functioning or even breaking may occur in connecting the signal plug on the IC and the gold wire when moving, molding, roasting the product, or sticking it to an electrical circuit board. In such cases, normal operation cannot be expected in the whole IC processes. Because the quality of wire bonding plays a critical role in the normal operation of an IC, the wire bonding process thus becomes the most important element in the IC assembly and packaging procedure. Several capability indices such as Cp, Cpu, Cpl and Cpk have been widely used in manufacturing industry to provide common quantitative measure on process potential and performance. However, those process capability indices are only appropriate to evaluate single-process products. Therefore, the objective of this study is to develop a process capability index so that the multi-process quality of a wire bonding can be evaluated. The relationship between the index and the yield as well as some statistical features of the index will also be discussed in this paper. Finally, a set of simple procedure for evaluation will also be provided to the industry for reference.