Avoidance of Bonding Pad Contamination Affecting Back-End Assembly Process

While the process fabrication and the electronic applications develop quickly, the die size and the package type also confront the improvement from the customers’ request to achieve the better signal performance in IC products. In cost consideration and marketing competition, most of commercial IC products still adopt the wire-bond technology, except some high performance products with solder/gold balls adhesion process. For consumer ICs, the gold wire is the major material to connect the IC chip and the lead frame through the bondability technology. In the recent era, the bond pad size and pitch is always shrinking. Therefore, the bond performance strongly depends on wire bond machine to provide lighters, thinner, and more reliable IC. After pad size shrinkage, the quality of pad is more impressed for wire bond reliability, especially in fine-pitch assembly process. It’s a challenge in reliability requirement. In this study, the root cause and promising solution of bond pad contamination were investigated. One is to improve the bonding yield in wire-bond process; the other is to promote the bonding reliability after the whole assembly process.