| 摘要 |
PURPOSE:To reduce the correcting time making highly precise correction feasible by a method wherein a metallic corrected material being heated, evaporated and decomposed by laser beam is deposited on a missing defective part within vacuum. CONSTITUTION:A missing defective photomask 7 is fixed to an enclosed correcting vessel 8 which is put into an air-tight state. Then a valve 12 is opened to exhaust the correcting vessels 8 simultaneously heating the vessel 8 and corrected material container 11 by heaters 16, 17. A corrected material 10 may be sublimated at 100-290 deg.C if it is bisbenzene chrome while at 50-100 deg.C if it is bisbenzene molybdenum and a corrected material gas may be introduced into the correcting vessels 8 by opening another valve 9. In such a status, the focussing point of laser beam 19 and a missing defective position are aligned under observation by means of irradiating optical system 23, a halfmirror 24, an eyepiece 25 and an objective lens 22. Then a defective part may be corrected by means of depositing chrome or molybdenum on the photomask 7 when the defective part is irradiated by laser beam 19 with a shutter 20 opened and closed after specified time lapse. |
