Taper Etching of Copper Using an Inductively Coupled O2 Plasma and Hexauoroacetylacetone

A one-step process consisting of copper lm oxidation with an O2 plasma and removal of the surface copper oxide by reaction with H(hfac) to form volatile Cu(hfac)2 and H2O was carried out for dry etching. The etching rate of Cu in the 50 to 700 A/min range depended on the substrate temperature, the H(hfac)/O2 ow rate ratio, and the plasma power. The optimum H(hfac)/O2 ow rate ratio was 1:1, suggesting that the oxidation process and the reaction with H(hfac) should be in balance. Cu patterning using a Ti mask was performed at a ow rate ratio of 1:1 at 250 C, and an isotropic etching prole with taper controllability was obtained. In addition, a self-aligned MgO layer obtained by annealing of a Cu(Mg) alloy lm played the role of an ecient hard mask for dry etching of copper lms. Dry patterning of Cu and Cu(Mg) lms with a tapered slope, which is necessary for advanced TFT/LCDs, was successfully obtained by employing the proposed one-stepF KCI Citation Count: 6