Patent ID: 7468320
Filing Date: 2008-12-23
Classification: H01L

Abstract:
1. A method for forming conductors with high electromigration resistance comprising forming a layer of dielectric on a substrate, forming at least one trench in said layer of dielectric, forming a metal liner in said trench, forming a conductor selected from the group consisting of copper and copper alloys on said metal liner filling said trench, forming a planarized upper surface of said conductor planar with the upper surface of said layer of dielectric, forming a conductive film over said upper surface of said conductor, said conductive film forming a metal to metal metallurgical bond to provide high electromigration resistance and high resistance to thermal stress voiding, annealing said substrate in one of an inert or reducing atmosphere at a temperature of at least 300° C. for at least 2 hours whereby excellent adhesion is obtained between said conductor and said conductive film, and wherein said conductive film has a thickness of 1 to 20 nanometers and is at least one member selected from the group consisting of CoWP, CoSnP, CoP, CoB, CoSnB, CoWB, NiB, Pd, In, and W.