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206)841-6000 RXECDTIW s " R YThis paper discusses effects of process parameters (viz. temperature, gas ratios and flow rates) for a chemical vapor deposition of tungsten on the resultant film properties and contact resistance. It is shown that deposition temperature has the greatest effect.Further, an inverse relationship is noted between contact resistance and temperature. K x T E N D m ABSTRACT Chemical vapor deposition of tungsten (CVD-W) has been recognized as a method to resolve the technological problems associated with the continued decrease in feature size in concert with increases in circuit complexity and density. This paper presents the results of a series of statistically designed experiments that were performed to improve the manufacturability of a blanket CVD-W process. The blanket process is used in two applications: (i) the tungsten film is patterned after deposition such that it provides contact plugs as well as interconnect, and (ii) the blanket tungsten is etched back to leave contact and/or via plugs.Key film properties and process parameters that were monitored include step coverage, reflectivity, deposition rate and uniformity, and bulk resistivity. The contact resistances to n-type polycrystalline silicon and titanium silicide were also monitored. Reflectivity measurements were referenced to a bare silicon wafer at a wavelength of 633 nm as the standard. The range of process conditions examined were as follows:June 12-1 3, 1990 VMIC Conference

Dilute HF/RCA and IEMC/SC2 cleans have been evaluated on two process lines with different metallic contamination levels. VPD-DSE-TXRF and SPV techniques were used to monitor the metallic contamination. Gate oxide integrity(GOI) tests were performed on several structures. Both HF/RCA and IMEC/SC2 cleans have shown good Qbd and Ebd results for the clean process line. Lower Qbd and Ebd values were obtained for both cleans in the relatively contaminated process line. These results suggest that poor GOI is related to the metallic contamination in the oxide or at the SiO2/Si interface.