APPARATUS FOR PRODUCING THIN FILM

PURPOSE:To obtain a thin film only with replacing a thin screen plate which is inexpensive and easily available, by dividing a container with an energy beam screen plate into a non-reaction space and a reaction space, and exhausting the both spaces of air while supplying a reaction gas to the reaction space. CONSTITUTION:An Si substrate 5 is disposed on a holder 6 in a reaction space 14, and the space 14 is evacuated of air through a tube 8b, while a valve 13 of a tube 12 is opened for evacuating air in a non-reaction space 10 defined between an energy beam entrance window 2 and a screen plate 3. The substrate 5 is heated, and after the reaction space 14 reaches a required degree of vacuum, a reaction gas is introduced therein from the tube 7 while exhasting air through the tube 8b so as to adjust the degree of vacuum to a predetermined degree. Then an incident energy beam 3 is supplied through the window 2 and screen plate 9 so that Si, SiO2 or the like is deposited on the substrate 5. During this operation, the valve 13 remains opened to continue air evacuation. With this constitution, a thin film can be formed without contaminating the expensive window only with appropriate replacement of the inexpensive screen plate 9. Further, the pressure difference between the spaces 14 and 16 can be reduced by adjustment, so that the screen plate 9 can be formed in a thickness less than 1mm. and the cost can be lowered.