| abstract |
The bumping process is comprising the steps of: providing a wafer; forming a patterned photo-resist with many openings corresponding to the bonding pad positions; forming a conductive layer on the exposed bonding pad and photo-resist; providing a lift-off thin film to lift the conductive layer on the photo-resist and leave the conductive layer on the openings; filling solder paste into the openings; and, finally, making a spherical bump by proceeding reflowing action for the solder paste and stripping off the photo-resist. |