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.