| 摘要 |
PURPOSE:To attain pattern dimensions with high in-plane uniformity by providing a heating means, a hot plate having a concentric recess, a temperature detecting means, and a temperature regulating means thereby heating a substrate uniformly. CONSTITUTION:A hot plate 1 is heated by means of a heater 2. Temperature of the hot plate 1 is detected by means of a thermocouple and regulated to a constant level by means of a temperature regulator 4. A photomask is mounted on the surface of the hot plate 1 and brought into tight contact therewith or a gap of about 0.1mm is set by inserting a spacer, e.g. a ball. Central temperature of the photomask can be lowered by making a recess in the center of the hot plate 1. The temperature drop depends on the diameter and the depth of recess an in case of a 152 mm square photomask of 6.3 mm deep, a recess of 50 mm diameter and 0.2 mm depth restrains the temperature rise from average temperature within 0.5 deg.C which is significantly low as compared with a case having no recess. Furthermore, temperature distribution can be improved signiticantly by employing a conical recess in the center. |
