METHOD FOR FORMING SELECTIVE PROTECTION LAYERS ON COPPER INTERCONNECTS

摘要

Disclosed is a method for forming selective protection layers on copper interconnects in a damascene process. A copper layer is deposited overlying a dielectric layer and filling interconnect trenches which are previously formed in the dielectric layer. The excess copper layer is polished by a chemical mechanical polishing process with a slurry comprising an aluminum organic substance. The aluminum organic substance reacts with copper via annealing to selectively form aluminum-copper alloys on the copper interconnects. The aluminum-copper alloys are then oxidized to form aluminum oxide protection layers capping the copper interconnects.