Patent ID: 8022543
Filing Date: 2011-09-20
Classification: H01L

Abstract:
1. A semiconductor structure comprising: a metal pad located on a metal interconnect structure; a dielectric passivation layer located over a periphery of said metal pad and containing an opening over a center portion of said metal pad; a first metallic diffusion barrier layer located on said metal pad; an elemental metal conductive layer comprising elemental Cu, elemental Au, elemental Ag, or elemental Ni and located on said first metallic diffusion barrier layer; a second metallic diffusion barrier layer located on said elemental metal conductive layer, wherein said second metallic diffusion barrier layer is a stack of a conductive metal layer and a conductive metal nitride layer, said conductive metal layer comprises an elemental metal and said conductive metal nitride layer comprises a conductive metal nitride derived from said elemental metal, and wherein said second metallic diffusion barrier layer and said first metallic diffusion barrier layer comprise different materials; and a wetting promotion layer located on said second metallic diffusion barrier layer and comprising a material that promotes wetting of a C4 ball, wherein said conductive metal layer of said second metallic diffusion barrier layer abuts said elemental metal conductive layer and said conductive metal nitride layer abuts said wetting promotion layer.