| 摘要 |
PURPOSE:To form a vapor deposition film of uniform composition on a substrate, by detecting film-forming rate with a film-thickness monitor arranged near the substrate, and by providing a control circuit which changes the distance between the substrate and the boat for vapor deposition source through comparing the detected rate with the reference signal. CONSTITUTION:A monitor 5 for film thickness is arranged near a substrate 4, hereby the formation of film on the substrate is found as resonance frequency. A control circuit 6 detects the resonance frequency and converts it into DC voltage according to the resonance frequency, and differentiates it to form differential signal which is compared with the reference signal. The result of comparison is fed to a displacement unit 7 for the substrate. When the differential signal is smaller than the reference voltage, the substrate 4 is brought near to the vapor deposition source boat 2, and when the differential signal is larger than the reference voltage, the approaching speed of the substrate 4 to the boat 2 is reduced. Hereby the rate of the growth of the film thickness on the substrate 4 is made constant. |
