CONTACT AND VIA STRUCTURES WITH COPPER INTERCONNECTS FABRICATED USING DUAL DAMASCENE TECHNOLOGY

A novel submicron process sequence was developed for the fabrication of CoSi2/n + Si, CoSi2/P + Si ohmic contacts and multilevel interconnects with copper as the interconnect/via metal and titanium as the diffusion barrier. SiO2 deposited by plasma enhanced chemical vapor deposition (PECVD) using TEOS/02 was planarized by the novel technique of chemical-mechanical polishing (CMP) and served as the dielectric. The recessed copper interconnects in the oxide were formed by chemical-mechanical polishing (dual Damascene process). Electrical characterization of the ohmic contacts yielded contact resistivity values of 10(-6) OMEGA-cm2 or less. A specific contact resistivity value of 1.5 x 10(-8) OMEGA-cm2 was measured for metal/metal contacts.