Method of making a bump on a substrate using multiple photoresist layers

摘要

A method of forming a bump on a substrate such as a semiconductor wafer or flip chip. The method includes the step of providing a semiconductor device having a contact pad and an upper passivation layer and an opening formed in the upper passivation layer exposing a portion of the contact pad. An under bump metallurgy is deposited over the upper passivation layer and the contact pad. A first photoresist layer is deposited in a liquid state so that the first photoresist layer covers the under bump metallurgy. A second photoresist layer is deposited and the second photoresist layer is a dry film photoresist. The unexposed portions of the first photoresist layer are removed. The remaining portions of the first photoresist layers are removed. The electrically conductive material is reflown to provide a bump on the semiconductor device.