Plasma Applications for Wafer Level Packaging Part 1

In this paper, typical plasma applications for WLP, such as improving Cu-PI interface adhesion, increasing the PI surface roughness, reducing the current leakage in WLP, the oxide removal from bump surface, avoiding microvoids between Cu seed layer and electric Cu plating layer, TSV cleaning, EMC removal from solder balls on wafer, and wafer-on-frame treatment, are mentioned. Some first-hand data are shown and discussed in the part 1 of this paper. The results indicate that plasma treatment is the recommended process for enhancing interface adhesion, roughening the surface, removing oxide on bumps, and avoiding microvoids in WLP.