METHOD FOR FORMING SOLDER BUMPS USING SACRIFICIAL LAYER

摘要

A barrier layer is formed over electrically conductive contact pads on a substrate such as a wafer. A photoresist layer is applied over the barrier layer, and openings in the photoresist layer are filled with solder to form solder bumps. The barrier layer may be removed from within the openings prior to filling the openings with solder. The process is applicable to fine pitch architectures and chip size packaging substrates. The photoresist layer and portions of the barrier layer outside of the openings are removed following solder fill.

主权项

1. A method of making a circuit, comprising:
forming a metallic layer on a substrate, wherein the substrate comprises a plurality of electrically conductive contact pads; applying a photoresist layer on the metallic layer; forming a plurality of first openings in the photoresist layer above the contact pads exposing portions of the metallic layer; etching the exposed portions of the metallic layer; placing solder over the contact pads; removing the photoresist layer with a chemical composition, the substrate being protected from the chemical composition by the metallic layer; and etching the metallic layer.