Fine pitch wafer bumping process

摘要

A fine pitch wafer bumping process comprises: providing a wafer that has a plurality of contact pads exposed by a passivation layer formed on the surface of the wafer, wherein an under bump metal (UBM) is formed respectively on each contact pad; on the surface of the wafer, forming a first mask film having a plurality of first openings that expose respectively the under bump metals (UBM); filling a first solder material respectively in the first openings; reflowing the first solder material into a plurality of solder posts; on the first mask film, forming a second mask film having a plurality of second openings that respectively expose the first openings; filling a second solder material respectively in the second openings; reflowing the second solder material and the first solder posts; removing the first and second mask films; and reflowing the first and second solder posts to form a plurality of bumps.