| 摘要 |
PURPOSE:To maintain the desired film thickness and to judge the decrease and increase in the film thickness when it is changed, by monitoring the film thickness so that the output signals corresponding to the reflectivities of the thin film with respect to two different optical wavelengths are matched with each other. CONSTITUTION:The light from a light projector 23 is reflected by a semitransparent mirror 24, and passes a monitoring window 26. The light is reflected by a thin film on a substrate 14, and divided into two luminous fluxes by a semitransparent mirror 38 and a reflecting mirror 39. The fluxes pass two filters 40a and 40b having different passing wavelengths and enter light receivers 25a and 25b. The output signals therefrom are inputted into a display device 28 and a control and operation panel 29 through amplifiers 27a and 27b wherein the amplifications are adjusted so that the output signals with respect to the passing wavelengths of the filters 40a and 40b before the formation of the thin film become equal. The moving speed of the substrate 14, the electric power of an electric heater for an vaporizing source which is not shown, or the like are controlled so that matching relationship is maintained and the desired film thickness is maintained. |
