REACTIVE ION ETCHING OF ION-PLATED CARBON-FILMS

Accurate pattern transfer by dry etching methods requires resistant ma sks. Carbon is a good candidate due to its low sputtering rate, and it is widely used for high temperature superconductor patterning. This p aper reports on radio frequency reactive ion etching of carbon films w ith diamond-like properties, deposited by ion plating at various bias voltages. Gold, polyimide and chalcogenide glass have been used as mas ks for deep carbon etching in oxygen, but failed to assure good select ivity Best pattern transfer has been observed using a two-layer resist system based on photoresist and Mo or Ta. The etching is carried out on two stages: (1) metal etching in CF4; (2) deep etching of carbon in oxygen plasma using the metal mask. A correlation has been found betw een film characteristics (etch rate, surface morphology, optical band gap) and the deposition bias voltage. The proposed technique is suitab le for fine patterning of carbon films and production of masks with hi gh ion etching resistance combined with good mechanical and thermal pr operties. (C) 1997 Elsevier Science Ltd. All rights reserved.