| 摘要 |
<p>PURPOSE:To enhance the cooling effect by a method wherein refrigerators are provided above and below a vacuum vessel for CVD processing so that both upper and lower surfaces of a substrate is evenly cooled down by isotropical diffusion when a vacuum vessel is within a low pressure region while by approaching the substrate when the pressure in the vacuum vessel exceeds a specific value. CONSTITUTION:A lower refrigerator 28 is provided on the upper end of a pedestal 27 while an upper refrigerator 29 is provided on the ceiling surface of a vacuum vessel 5. Firstly, a cooling pipe 32 of the lower refirgerator 28 and another cooling pipe 35 of a cooling block 34 are communicated with cooling water at the uppermost position (almost intermediate position between the upper refrigerator 29 and the lower refrigerator 28) while the vacuum vessel 5 evacuated at a high degree of vacuum is fed with nitrogen gas through the intermediary of a nitrogen gas feed pipe 42 so as to cool down the glass substrate 1. At this time, the nitrogen gas is diffused isotropically at low pressure region to evenly gas-cool down the upper and lower surface of the glass substrate 1 however, when the pressure in the vacuum vessel 5 is boosted, the cooling efficiency is decreased so as to decelerate the cooling rate. Finally, the glass substrate 1 is lowered at the position near the upper part of the lower refrigerator 28 so as to lead-in the nitrogen gas from another nitrogen gas feed pipe 7.</p> |
