Patent ID: 7015130

Claim:
A method for making bumps on a wafer, comprising the steps of: providing a wafer with an active surface having a plurality of bonding pads thereon; forming an UBM (Under Bump Metallurgy) layer over the active surface of the wafer to connect the bonding pads; forming a photoresist layer on the UBM layer; creating a plurality of openings in the photoresist layer in locations corresponding to the bonding pads of the wafer; forming a liquid photoresist in the openings of the photoresist layer; exposing and developing the liquid photoresist for modifying the openings of the photoresist layer; forming a plurality of bumps in the openings in photoresist layer, the bumps being bonded onto the UBM layer; removing the photoresist layer and the liquid photoresist; etching the UBM layer to form a plurality of UBM pads under the bumps, using the bumps as a mask; and reflowing the bumps on the UBM pads.