CHEMICAL-VAPOR DEPOSITION OF COPPER FROM HEXAFLUOROACETYLACETONATO COPPER(I) VINYLTRIMETHYLSILANE - DEPOSITION RATES, MECHANISM, SELECTIVITY, MORPHOLOGY, AND RESISTIVITY AS A FUNCTION OF TEMPERATURE AND PRESSURE

Chemical vapor deposition (CVD) of copper from (hfac)copper(I)VTMS, where hfac = hexafluoroacetylacetonato and VTMS = vinyltrimethylsilane has been studied as a function of temperature and pressure. Analogous to other (hfac)Cu(I)L compounds [L = trimethyl phosphine (PMe3), 1,5-cyclo-octadiene (COD) and 2-butynel, (hfac)CuVTMS also deposits pure copper films via a quantitative thermally induced disproportionation reaction. The reaction kinetics of (hfac)CuVTMS were examined in a warm-wall differential reactor over the temperature range of 130 to 200-degrees-C and pressure range of 10 to 500 mTorr. Deposition rates of up to approximately 5000 angstrom/min at 190-degrees-C and 500 mTorr were obtained. Apparent activation energies of 43(5) and 10(2) kcal/mol at 10 and 500 mTorr precursor pressure, respectively were obtained. The deposition rate was nearly first order over precursor partial pressure of 10 to 30 mTorr and zero order over 50 to 500 mTorr at 160-degrees-C. The data are consistent with a mechanism of chemisorption of (hfac)CuVTMS, dissociation to form (hfac)Cu and VTMS, disproportionation of (hfac)Cu to form Cu metal and Cu(hfac)2, and desorption of Cu(hfac)2 and VTMS. A strong dependence of film resistivity on precursor partial pressure was observed. Selectivity for tungsten (W) surfaces in the presence of PECVD SiO2 was not observed under the conditions employed.