Method of using an electroless plating for depositing a metal seed layer for the subsequent plated backside metal film

Abstract

A method of backside metal process for semiconductor electronic devices, particularly of using an electroless plating for depositing a metal seed layer for the plated backside metal film. The backside of a semiconductor wafer, with electronic devices already fabricated on the front side, is first coated with a thin metal seed layer by electroless plating. Then, the backside metal layer, such as a gold layer or a copper layer, is coated on the metal seed layer. The metal seed layer not only increases the adhesion between the front side metal layer and the backside metal layer through backside via holes, but also prevents metal peeling after subsequent fabrication processes. This is helpful for increasing the reliability of device performances. Suitable materials for the metal seed layer includes Pd, Au, Ni, Ag, Co, Cr, Cu, Pt, or their alloys, such as NiP, NiB, AuSn, Pt—Rh and the likes.