THIN FILM FORMING APPARATUS, FILM THICKNESS MEASURING METHOD AND FILM THICKNESS SENSOR

摘要

Provided is a technology of accurately measuring a film thickness even when peeling is generated. A differential frequency (?f0) is calculated from the value of a resonance frequency (f0) of a film thickness sensor (15) at a current time (a0) and the value of a resonance frequency (f1) at a past time (a1) just before the current time, and whether there has been peeling or not is detected based on the sign of the calculated value and the results of comparison with a reference value. When there has been peeling, a peeled film thickness (?t0) is added to an increased film thickness value (T) obtained from a resonance frequency (fx) measured at a future time (ax) to obtain a modified film thickness value (T'), and the value is converted into the film thickness of a film forming object (18), and end of film formation is judged by comparison with a target value. Thus, an accurate thickness value of a thin film on the surface of the film forming object (18) can be obtained even when peeling is generated on the film thickness sensor (15).