| 摘要 |
PROBLEM TO BE SOLVED: To provide a projection aligner which can provide good pattern projection by suppressing a distortion of a mask caused by thermal deformation of a mask holder. SOLUTION: A mask 100 is accommodated in grooves 53 of holding frames 50 and 52 of a mask holder 10. When air, having a constant temperature and a constant flow rate is supplied from an air conditioner 12 in such directions as shown by arrows F, the air is passed sequentially through pipes 14, air inlets 58 and passages 56, and then discharged from outlets 54 toward the mask 100. This causes ends of the mask 100 to be pushed from three directions and to be held by holding frames 50 and 52 but in non-contact relationship therewith. For this reason, the heat emitted from the mask 100 is prevented from being transmitted to the mask holder 10. Air discharged from the outlets 54 cools the mask 100 and also lightens a magnification change of the mask 100 caused by thermal expansion. |
