Plasma etching of ceramic superconducting films at low temp. - using photoresist masking films and a triode generated etching plasma in a reactive gas contg. chlorine@

摘要

The film of a metal oxide superconducting ceramic material is masked with an etch mask and exposed to a dry etching process, using a chemically reactive ionic species, to remove unmasked material. The masking layer can be a resist directly deposited on the superconducting film and the etching is carried out below 120 deg.C using a triode arrangement with ion energy over 100 eV, pref. at least 500 eV. The resist layer is removed after the etch, pref. using an O2 plasma. The gas pressure during the plasma discharge is pref. 0.1-10 Pa, esp. 1-5 Pa, in a gas which contains at least one halogen or a halogen-cpd. and pref. another gaseous component. USE/ADVANTAGE - The process allows etching of ceramic superconductor layers at low temps., avoiding degradation of the layers, at high etch rates. The masking layer needed is easily formed and defined and can be easily removed afterwards. The etch rate obtd. varies linearly with HF energy level to 6 nm/min. at an energy level below 100W and is twice the rate obtd. using no LF energy applied to the lower electrode.