CONTACT AND VIA STRUCTURES WITH COPPER INTERCONNECTS FABRICATED USINGDUAL DAMASCENE TECHNOLOGY

A novel submicron process sequence was developed for the fabrication o f CoSi2/n + Si, CoSi2/P + Si ohmic contacts and multilevel interconnec ts with copper as the interconnect/via metal and titanium as the diffu sion barrier. SiO2 deposited by plasma enhanced chemical vapor deposit ion (PECVD) using TEOS/02 was planarized by the novel technique of che mical-mechanical polishing (CMP) and served as the dielectric. The rec essed copper interconnects in the oxide were formed by chemical-mechan ical polishing (dual Damascene process). Electrical characterization o f the ohmic contacts yielded contact resistivity values of 10(-6) OMEG A-cm2 or less. A specific contact resistivity value of 1.5 x 10(-8) OM EGA-cm2 was measured for metal/metal contacts.