| 摘要 |
PURPOSE:To prevent the occurrence of pinhole defects and to enhance the yield of production. CONSTITUTION:An opaque film of Cr, CrO2, etc., is formed as a first mask pattern 2 on an optical glass substrate 1 and an opaque film of Al, Mo, etc., is formed as a second mask pattern 4 on the pattern 2. The width (b) of the second pattern 4 is made slightly smaller than the width (a) of the first pattern 2 by about 2mum. Since pinholes in the pattern 4 hardly overlap pinholes in the pattern 2, most of the resulting mask pattern is made free from pinhole defects. |
