Patent ID: 8193636

Claim:
A chip package comprising: a semiconductor chip comprising a silicon substrate, a transistor in or over said silicon substrate, a first dielectric layer over said silicon substrate, a metallization structure over said first dielectric layer, wherein said metallization structure comprises a first metal layer and a second metal layer over said first metal layer, a second dielectric layer between said first and second metal layers, a passivation layer over said metallization structure, over said first and second dielectric layers and over said transistor, wherein an opening in said passivation layer is over a contact point of a metal pad of said metallization structure, and said contact point is at a bottom of said opening, wherein said metal pad comprises a first copper layer having a thickness between 0.5 and 3 micrometers and a barrier metal layer at a bottom and a sidewall of said first copper layer, wherein said passivation layer comprises a nitride layer; a metal bump on said contact point, wherein said metal bump is connected to said contact point through said opening, wherein said metal bump comprises an aluminum-free adhesion layer on said contact point, a copper-containing seed layer on said aluminum-free adhesion layer, and a second copper layer with a thickness between 5 and 30 micrometers on said copper-containing seed layer, wherein said aluminum-free adhesion layer is at a bottom of said second copper layer, but not at a sidewall of said second copper layer; a flexible circuit film comprising a first polymer layer, a second polymer layer and a copper trace comprising a portion between said first and second polymer layers; a tin-alloy layer between said second copper layer and said copper trace, wherein said tin-alloy layer comprises gold, wherein said tin-alloy layer is vertically over said sidewall of said second copper layer; and a polymer between said semiconductor chip and said flexible circuit film, wherein said polymer contacts said semiconductor chip and said flexible circuit film and encloses said metal bump.