| 摘要 |
PURPOSE:To increase a yield by preventing the reaction products adhering to a duct cover from being detached and adhering to a wafer by providing heating machanism for the duct cover. CONSTITUTION:The heater 11 for increasing the surface temperature of he duct cover covering a dispersion head 5 and for preventing reaction products 8 adhering to the duct cover 4 from being detached is arranged around the duct cover 4. A tray 2 on which a wafer 3 is put is sent under the dispersion head 5 which sprays a reactive gas onto the upper surface of the wafet 3 which has been heated, thereby forming a CVD film. Unreacted gas in part is drawn into the duct cover 4 and enters into a reaction with the air sent from the outside to produce the reaction products 8 adhering to the internal surface of the duct cover 4. As the surface temperature of the duct cover 4 is high, the reaction products 8 become a thick film and are not detached. |
