Optical film thickness controlling method, optical film thickness controlling apparatus, dielectric multilayer film manufacturing apparatus, and dielectric multilayer film manufactured using the same controlling apparatus or manufacturing apparatus

摘要

To provide a method of controlling film thickness of dielectric multilayer film, such as optical thin film, with high precision, an optical film thickness controlling apparatus and a dielectric multilayer film manufacturing apparatus that can control the film thickness based on the same method, and dielectric multilayer film manufactured using the controlling apparatus or manufacturing apparatus. An optical film thickness controlling apparatus includes a film formation device 15 having a rotatable substrate 23 and a sputtering target 28, a photodiode 16 that detects each of a plurality of monochromatic light beams applied to the rotatable substrate along a radius thereof at predetermined intervals, and an A/D converter 17, in which a movable shutter 29 that moves along the direction of the radius of the rotatable substrate 23 to shut off film formation on the substrate 23 is provided between the substrate 23 and the target 28. From each of the monochromatic light beams detected by the photodiode 16 and the A/D converter 17, a quadratic regression function of reciprocal transmittance is calculated by a least squares method, and a CPU 18 and a motor driver 19, which indicate motion of the movable shutter based on each predicted value of the film growing time when the latest surface layer film reaches to predetermined optical film thickness, move the movable shutter 29 to shut off the film formation at the film formation region where the predetermined optical film thickness is reached to.