Patent ID: 7553751

Claim:
A method of forming a bump, the method comprising: forming a passivation layer on a wafer having a pad, such that the passivation layer exposes a portion of the pad; forming a first photoresist pattern on the passivation layer, the first photoresist pattern having a first opening that exposes the pad; forming a first under bump metallurgy (UBM) layer on the pad; forming a second UBM layer on the first photoresist pattern; forming a photoresist layer over the first and the second UBM layers; forming a groove in the photoresist layer so as to expose the second UBM layer by exposing and developing the photoresist layer; etching the second UBM layer exposed by the groove; forming a second photoresist pattern by re-exposing and re-developing the photoresist layer disposed on the first UBM layer to form a second opening that extends from the first opening; forming a solder bump in the first and the second openings; and applying a stripper into the groove to remove the second photoresist pattern and the first photoresist pattern, thereby removing the second UBM layer by a lift-off method.