Comparison of Experiments with a Lumped Parameter Model of the Plasma Assisted Chemical Vapor Deposition of Copper

Abstract

Experiments show that pure copper films can be formed at temperatures below 190 °C by plasma assisted chemically vapor deposited copper(II)‐hexafluoroacetylacetonate. A fundamental surface reaction mechanism has been derived for the reaction between dissociatively adsorbed precursor and atomic hydrogen produced in the plasma. The mechanism suggests that the deposition rate is proportional to and film purity improves with an increase in atomic hydrogen concentration. A new lumped parameter model has also been developed that agrees very well with experiments, to relate the operating conditions to the concentrations of and atomic hydrogen. Our model shows that at temperatures above 200 °C, surface recombination of atomic hydrogen decreases adsorbed [H] leading to copper films possessing high resistivity. It also indicates that at plasma powers above 60 W, high electron concentrations lead to the gas‐phase decomposition of the precursor and high film resistivity. An apparent activation energy of 5.0 kcal/mol is also suggested for the deposition, by the experiments and the reactor model.