A novel submicron Al contact filling technology for ULSI metallization

A novel Al contact filling technology utilizing the combination of excimer laser planarization and chemical mechanical polishing (CMP) has been developed. In this technique, the newly developed excimer laser planarization technology is first employed to fill submicron, high aspect ratio (>1.5) contact/via with an Al alloy. The laser processed films including barrier layer are subsequently removed by a CMP process, leaving Al plugs intact in the contact/via. A second metal is next deposited to interconnect the Al plugs and patterned by the standard lithography and etch techniques. This technology alleviates most of the problems including poor surface morphology and potential difficulty in submicron pattern definition intrinsic to the high temperature sputtered films. Full electrical characterizations of device wafers processed by this technology yielded satisfactory results. This Al plug technology has been demonstrated to be capable of filling submicron contact/via with a wide process window and an improved surface morphology for submicron patterning