CHEMICAL-VAPOR-DEPOSITION OF COPPER FROM (HFAC)CUL (L=VTMS AND 2-BUTYNE) IN THE PRESENCE OF WATER, METHANOL, AND DIMETHYL ETHER

The CVD of Cu using (hfac)Cu(VTMS) (hfac = hexafluoroacetylacetonate, VTMS = vinyltrimethylsilane) and (hfac)Cu(2-butyne) in the presence of water and other reagents has been studied. The overall CVD reaction i nvolving disproportionation of these copper(I) compounds in the presen ce of water is similar to the overall reaction in the absence of water . The Cu films deposited at low water vapor flow rate (0.2 seem) exhib ited near bulk resistivities (similar to 2.0 mu Omega cm) and dense su rface morphologies while the Cu films deposited at higher water vapor flow rate (2.4 seem) showed significantly higher resistivities (simila r to 12 mu Omega cm) and porous morphologies. At higher water flow rat es the deposition rate and conductivity of the films were reduced as a result of Cu2O incorporation. The presence of water during CVD is bel ieved to introduce a reaction parallel to the main CVD disproportionat ion reaction via reaction of water with surface-bound [Cu(hfac)] and r esults in the incorporation of copper(I) oxide (Cu2O) in the Cu films. Labeling experiments using H2O18 showed that the oxygen incorporated into the films (SIMS) at high water-flow rates was derived from reacti on with H2O18. The deposition rate enhancements with methanol and dime thyl ether showed similar trends as a function of flow rate but lower overall rate enhancements compared to water. The presence of water is believed to aid the dissociation of the L from the (hfac)CuL by hydrog en bonding with the hfac ligand and/or oxygen donation to the copper(I ) center. The incorporation of Cu2O was completely suppressed by intro duction of hfacH vapor along with the precursor and water vapor during CVD of Cu.