| 摘要 |
PURPOSE:To detect the attenuating amount of infrared rays accurately, in an infrared-ray transmitting type film-thickness measuring device, by removing the effect due to the interference of a film by a plurality of filters. CONSTITUTION:The width of detecting wavelengths of a detector is made wide. A chopper is provided in front of the detector. A plurality of filters, i.e., three or more, having a single wavelength characteristics and an equal interval in 0.1mum unit or less are attached to the chopper. Transmitted energy is captured by the detector. The amount of the minimum energy including interference energy is made to be the amount of true energy, which is transmitted through a film, and the thickness of the film is computed in the detector. In this way, the effect of the interference due to the film thickness is removed, the amount of transmission attenuation can be detected accurately, and the true thickness can be measured. |
