Method for pattern-wise etching of a metallic coating film

摘要

The invention provides an improved process for providing wirings and electrodes of aluminum film on the surface of a substrate. Instead of the conventional method of directly forming an organic resist layer on the metal film, a remarkable improvement in the fineness and accuracy of patterning is obtained by providing a subsidiary masking layer, mainly composed of silicon dioxide, between the metal film and the organic resist layer; and pattern-wise etching by first etching the subsidiary masking layer through a patterned mask of the organic resist layer with a fluorine-containing etching gas to form a patterned subsidiary masking layer, and then etching the metal film with a chlorine-containing etching gas through the mask of the patterned subsidiary masking layer, followed by final removal of the remaining subsidiary masking layer.