METHODS IN OR RELATING TO PHOTOMASKS

摘要

1277037 Photo-masks WESTERN ELECTRIC CO Inc 2 July 1969 [3 July 1968] 33410/69 Heading G2M [Also in Divisions B6 and C7] Photo-masks for exposing photo-resists comprise a rigid transparent substrate having the mask areas defined by a layer of inorganic material having a thickness of up to 3Á, a Moh hardness of at least 4 and being at least 20% transparent to at least a portion of the visible spectrum but less than 3% transparent to radiation suitable for exposing a photo-resist. Preferred materials are Pb silicate, iron oxide and vanadium oxide. A mask is prepared by forming a film of Pb silicate on a glass substrate by sputtering using Pb and Si cathodes in an O 2 atmosphere, and then etching the film by a photo-resist technique using hot H 2 O 2 .