The Impact of Copper Contamination on the Quality of the Second Wire Bonding Process using X-Ray Photoelectron Spectroscopy (XPS) Method

摘要

A lot of wedge bonding failures were observed on the leadframe (LF) type A due to non stick on lead (NSOL) during the second wire bonding process of TQFP package. The copper ion contamination from the plating process was identified as one of the key factors that attributed to the NSOL failures. Surface analyses were performed in terms of X-ray photoelectron Spectroscopy (XPS) on the surface of leadframe type A. It was found that as received silver-plated surface of the copper leadframe type A was contaminated by the copper. After the copper contamination was solved out in plating process, the design of experiment (DOE) was implemented for the verification of the influence of copper contamination on the quality of the second bonding process. It was confirmed that copper contamination dramatically reduced the strength of wedge bonding. The wedge pull test showed that NSOL failures were not observed if the copper ion contamination in the plating process was well controlled.