Patent ID: 7273803
Filing Date: 2007-09-25
Classification: B32B,Y10T

Abstract:
1. A method for forming an interconnection structure for flip-chip attachment of microelectronic device clips to packages, comprising: forming an adhesion layer over a substrate; forming a seed layer over the adhesion layer, forming a resist layer over the seed layer, the resist layer having an opening that exposes the seed layer; forming a first solderable layer over the seed layer through the opening in the resist layer, wherein the first solderable layer comprises Cu; forming a diffusion barrier layer over the first solderable layer through the opening in the resist layer, wherein the diffusion barrier layer comprises CoWP; forming a second solderable layer over the diffusion barrier layer through the opening in the resist layer, wherein the second solderable layer comprises a layer of Ni having a thickness less than about 4 microns; removing the resist layer; removing portions of the seed layer and the adhesion layer that extend beyond the first solderable layer, the diffusion barrier layer and the second solderable layer; and forming at least one solder ball over the second solderable layer.