COMPARISON OF EXPERIMENTS WITH A LUMPED-PARAMETER MODEL OF THE PLASMA-ASSISTED CHEMICAL-VAPOR-DEPOSITION OF COPPER

Experiments show that pure copper films can be formed at temperatures below 190 degrees C by H-2, plasma assisted chemically vapor deposited copper(II)-hexafluoroacetylacetonate. A fundamental surface reaction mechanism has been derived for the reaction between dissociatively ads orbed precursor and atomic hydrogen produced in the plasma. The mechan ism suggests that the deposition rate is proportional to [Cu(HFA)(2)]( 1/2)[H] and film purity improves with an increase in atomic hydrogen c oncentration. A new lumped parameter model has also been developed tha t agrees very well with experiments, to relate the operating condition s to the concentrations of Cu(HFA)(2) and atomic hydrogen. Our model s hows that at temperatures above 200 degrees C, surface recombination o f atomic hydrogen decreases adsorbed [H] leading to copper films posse ssing high resistivity. It also indicates that at plasma powers above GO TN, high electron concentrations lead to the gas-phase decompositio n of the precursor and high film resistivity. An apparent activation e nergy of 5.0 kcal/mol is also suggested for the deposition, by the exp eriments and the reactor model.