Patent ID: 7713861
Filing Date: 2010-05-11
Classification: H01L

Abstract:
1. A method of forming a metallic bump on an I/O pad on an active side of a semiconductor device for establishing electrical contact to said I/O pad, comprising the steps of: forming an under bump metallurgy (UBM) on a top side of said I/O pad; arranging an isolative layer and a metallic foil sequentially in this order on a top side of said UBM; forming a via by removing a part of said isolative layer and said metallic foil so that a substantial part of said top side of said UBM is exposed; forming a thin metallic layer at least in said via so that said thin metallic layer is connected to said metallic foil; forming a resist on a top side of said metallic foil without covering said via coated with said thin metallic layer; forming said metallic bump in said via on said top side of said UBM by using said metallic foil and said thin metallic layer jointly to conduct electrical current; and removing said resist and said metallic foil from both sides of said metallic bump.