Dry etching of copper film with hexafluoroacetylacetone via oxidation process

Abstract

Dry etching of Cu film was achieved via oxidation process using oxidizing agents such as O-2 plasma, O-3, Or O-3 plasma, followed by the removal process of the copper oxides (CuOx) by reaction with hexafluoroacetylacetone [H(hfac)] to form volatile copper compound, [bis-hexafluoroacetylacetonate: Cu(hfac)(2)] and H2O. The etching rate was increased with the increase of etchant [H(hfac) and O-3] flow rate, plasma power, and substrate temperature. Oxygen radical concentration is the highest in the plasma generated with ozone, which leads to the highest etching rate up to 1400 Angstrom/min. The etch rate dependence on the substrate temperature showed the activation energy of about 7 kcal/mol and gas phase transport seems to be the rate controlling step. (C) 1999 American Vacuum Society. [S0734-211X(99)03201-1].