| 摘要 |
PURPOSE:To improve optical characteristic, chemical durability and mechanical durability by using chromium contg. 1-10% boron in an atomic ratio as a target in the stage of forming a photomask blank by forming a chromium film contg. boron on a transparent substrate by a sputtering method. CONSTITUTION:Low-expansion glass having a smooth and flat surface or quartz glass or the like is used as the transparent substrate 1 and the chromium film contg. boron and nitrogen is used as a light shielding film 2. The control of an etching rate and side etching amt. is possible if the boron is incorporated into the light shielding chromium film. The chemical durability is improved if the nitrogen is incorporated into the light shielding chromium film. The chromium, boron and nitrogen to be incorporated into the light shielding film are required to be respectively in 50-69%, 1-10%, 30-40% ranges in the atomic ratio. The introduction of the boron and nitrogen into the chromium film is executed simply by executing sputtering in a gas prepd. by mixing gaseous nitrogen with gaseous argon. The optical characteristic, chemical durability and mechanical durability are thereby improved. |
