Patent ID: 7790599

Claim:
A method of fabricating an interconnect structure, the method comprising: forming an interconnect feature in an upper portion of a first insulating layer; deposing a dielectric capping layer over said interconnect feature and said first insulating layer; depositing a second insulating layer over said dielectric capping layer; etching a portion of said second insulating layer to form at least one via opening, wherein said at least one via opening exposes a portion of said interconnect feature; bombarding said portion of said interconnect feature for defining a gauging feature in a portion of said interconnect feature; etching said via gauging feature for forming at least one undercut area adjacent to said interconnect feature and said dielectric capping layer; depositing a noble metal layer, said noble metal layer filling said at least one undercut area of said via gauging feature to form a metal cap; depositing a metal layer over said metal cap; and wherein said at least one etched undercut feature extends alone an entire surface of said interconnect feature.