DOUBLE-LEVEL CU INLAID INTERCONNECTS WITH SIMULTANEOUSLY FILLED VIA PLUGS

A double-level Cu interconnection process for lower submicron generati on ULSIs was developed. Cu interconnects were successfully formed by C u/WSiN sputtering, XeCl excimer laser annealing and Cu/WSiN chemical m echanical polishing. The composition of the WSiN barrier metal was opt imized to WSi0.6N and the diffusion barrier capability was confirmed b y physical analyses and electrical measurements. The electrical resist ivity of the inlaid Cu was 1.9+/-0.1 mu Omega . cm and contact resisti vity between the first-level Cu and the second-level Cu was (1.54-5.78 ) x 10(-9) Omega . cm(2). The electromigration lifetime of laser-annea led Cu/WSiN wiring was found to be one order of magnitude longer than that of previously reported Cu interconnects. The activation energy fo r electromigration was determined to be 1.1 eV.