| 摘要 |
PURPOSE:To discriminate a substrate with a semipermanent symbol and to eliminate any harm in making circuit patterns, by applying a lustrous marking by laser working in the matted part in the peripheral part on the side of the substrate. CONSTITUTION:A substrate for a photomask blank in a matted state having the as-cut-out peripheral part on the side is set as a work piece in a laser working machine, then the laser light from a laser oscillator is irradiated through a lens 8 to a mask 7 having a prescribed symbol to be marked. A prescribed symbol 9 in a lustrous state is thus obtd. in the matted part 10 in the peripheral part on the side of the substrate. The symbol is the sharp symbol marked on the matted part as a background, and permits identification of the kinds of mat and thin films with checking at just one place, and gives no harms in the post stage of forming patterns for IC circuits. Equally good results are obtained by using electron beam working and ultrasonic working. |
