Microbump development on small bump pitch (50μM and lower)

Further miniaturization of electronic systems by 3D technologies has increased interest in the semiconductors community. Device scaling has become exponentially challenging. One of the challenges for fine pitch Cu/Sn stacking is to obtain high bump uniformity. Enhanced electroplating of microbumps is shown when plating is done after a plasma treatment or descum. The descum conditions influence the bump profile and bump adhesion strength which has been confirmed by shear testing. Best known method (BKM) is selected by analyzing resist consumption, plating uniformity, bump undercut and shear strength.