| 摘要 |
PURPOSE:To increase the transmittance for visible light of a transparent substrate by executing sputtering to a target consisting of chromium in an atmosphere contg. an inert gas, gaseous nitrogen and oxidative gas. CONSTITUTION:A thin film which shields light of a photosensitive region is formed on a transparent substrate. Metallic chromium is used as the target and is subjected to sputtering in the atmosphere contg. the three components; the inert gas such as argon, gaseous nitrogen and oxidative gas. The oxidative gas is selected from gaseous oxygen, carbon dioxide and carbon monoxide. The gaseous atmosphere is composed, by molar ratio, of 1-5 gaseous nitrogen and about 0.05-0.5 oxidative gas by 1 inert gas. The sputtering is executed under 1.6-2.4X10<-2> total gaseous pressure and at 1-5A, 300-500V by a DC magnetron method. The transmittance for visible light is thus remarkably improved and the good photomask blank is obtd. |
