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 involving disproportionation of these copper(I) compounds in the presence 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 sccm) exhibited near bulk resistivities (∼2.0 μΩ cm) and dense surface morphologies while the Cu films deposited at higher water vapor flow rate (2.4 sccm) showed significantly higher resistivities (∼12 μΩ cm) and porous morphologies. At higher water flow rates the deposition rate and conductivity of the films were reduced as a result of Cu 2 O incorporation. The presence of water during CVD is believed to introduce a reaction parallel to the main CVD disproportionation reaction via reaction of water with surface-bound [Cu(hfac)] and results in the incorporation of copper(I) oxide (Cu 2 O) in the Cu films. Labeling experiments using H 2 O 18 showed that the oxygen incorporated into the films (SIMS) at high water flow rates was derived from reaction with H 2 O. 18 The deposition rate enhancements with methanol and dimethyl 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 hydrogen bonding with the hfac ligand and/or oxygen donation to the copper(I) center. The incorporation of Cu 2 O was completely suppressed by introduction of hfacH vapor along with the precursor and water vapor during CVD of Cu.