| 摘要 |
PURPOSE:To prevent the drop-out of a photomask pattern by forming a photomask blank of a substrate laminated with a thin transparent film contg. at least one of Al and B as well as Si and O on the main surface of a base body consisting of quartz glass and a thin chromium film laminated on the thin transparent film laminated on the main surface. CONSTITUTION:The quartz glass is first cut to a prescribed size and both main surfaces are polished, cleaned and dried, by which the base body 81 is obtd. The thin transparent film 82 (100Angstrom film thickness) consisting of Si, B and O is stuck on one main surface by using the target formed by sintering SiO2 powder incorporated therein with 10wt% B2O3 and by a high-frequency sputtering method to form the substrate 8. The thin chromium film 9 (3.0 optical density and 800Angstrom film thickness) is further laminated by a DC magnetron sputtering method on the film 82 of such substrate 8 to form the photomask blank 7. The thin transparent film consisting of Si, Al and O may be formed as well by using the target formed by sintering the SiO2 powder incorporated therein with Al2O3. |
