Method of forming solder bump with reduced surface defects

摘要

A method of forming a solder bump may involve forming a first photoresist pattern on a wafer having a pad. The first photoresist pattern may have an opening that exposes a portion of the pad. A first under bump metallurgy (UBM) layer may be formed on the pad, and a second UBM layer may be formed on the first photoresist pattern. A second photoresist pattern may be formed that exposes the first UBM layer. A solder bump may be formed in the opening. The second photoresist pattern and the first photoresist pattern may be removed using a stripper, thereby removing the second UBM layer by a lift-off method.