Patent ID: 8178435

Claim:
A method of forming a post passivation system, comprising: providing a silicon substrate, a first interconnect metal layer over said silicon substrate, a second interconnect metal layer over said first interconnect metal layer, a dielectric layer between said first and second interconnect metal layers, a first metal pad over said silicon substrate, and a passivation layer over said first and second interconnect metal layers, wherein said passivation layer comprises a nitride layer, wherein a first opening in said passivation layer is over a first contact point of said first metal pad and has a width greater than 0.1 micrometers, and said first contact point is at a bottom of said first opening, wherein said passivation layer has a top surface with a first region and a second region, wherein said first opening is between said first and second regions; forming a first polymer layer on said passivation layer, wherein a second opening in said first polymer layer exposes said first opening and said first and second regions, wherein said forming said first polymer layer comprises exposing and developing said first polymer layer; forming a patterned circuit layer over said first polymer layer, on said first and second regions and on said first contact point, wherein said patterned circuit layer comprises a coil over said first polymer layer, wherein said coil is connected to said first contact point through said first and second openings, wherein said forming said patterned circuit layer comprises forming a glue layer, next forming a seed layer over said glue layer, next forming a bulk metal layer over said seed layer, and then removing said seed layer and said glue layer not under said bulk metal layer; and forming a second polymer layer over said patterned circuit layer.