| 摘要 |
PURPOSE:To stabilize a furnace temperature and to prevent an increase of temperature in a clean room by providing heat shielding means having a reach including both a furnace and a clean room to prevent convection of the air between the furnace side and the clean room side. CONSTITUTION:A clean room 8A is arranged at the front end of, and in touch with, a furnace 2 of a pressure-reduced CVD device. At the rear end of the furnace 2, a clean room 8B is arranged similarly. A reaction tube 6 is inserted into a heat insulating member 4 fixed to the inside of the furnace 2 and the front end of this reaction tube 6 faces the clean room 8A and the rear end faces the clean room 8B. Between the end parts of the reaction tube 6 and the end parts of the furnace 2, a water cooling jacket 34A as a heat shielding means which insulates the furnace 2 from the clean room 8A while covering an exposed part of the reaction tube 6 with its reach including said two end parts. On a periphery of the water cooling jacket 34A, a water inlet pipe 38 for circulating a cooling water spirally is arranged. The existence of the water cooling jackets 34A and 34B enables the restraint of variation of temperature of the furnace 2 caused by convection of the air, resulting in the stabilization of the temperature of the furnace 2.
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