Optical film thickness meter and thin film forming apparatus provided with optical film thickness meter

摘要

High precision optical film thickness that can be measured and the spectral characteristics of the optical film thickness meter and optical film thickness meter provides a thin film forming apparatus having a. Optical film thickness meter is provided with a light emitter 11, and the reflecting mirror 17, a light receiver 19, is composed of a spectroscope 20, a plate group for the measurement light incident direction ( ) (S) on the opposite side, a reflecting surface substantially perpendicular to the optical axis of measurement light and a reflection mirror arranged (17). Further, the plate group (S) is, are arranged with a predetermined inclination angle ( ) to the optical axis of measurement light. Measuring light (outgoing light and reflected light) is transmitted through the group to the plate (S) 2 times, it is possible to increase the amount of change in the transmittance (amount of light), it is possible to improve the control accuracy of the thickness measurement. In addition, it is possible to prevent occurrence of measurement error due to the difference in the transmission position, and also, since the measurement board through a predetermined path that is not transmitted through two determinations light receiver (19) no longer detected in the side, can be the measurement of the film thickness and the optical spectral characteristics with high accuracy. ;