The photothermal laser induced CVD of Cu from its hexafluoroacetylacetonate trimethylvinylsilane deriv. was studied as a function of added H2O vapor pressure. The height, width, elec. cond., and chem. compn. of the deposited Cu lines are measured. Under anhyd. conditions, the lines were characterized by a low growth rate, high C contamination, and poor elec. resistivity. In the presence of H2O vapor, a high growth rate (1800 mm/min) and high purity Cu lines were obtained with a resistivity ratio of 1.1.