Patent ID: 8941843
Filing Date: 2015-01-27
Classification: G01B,G01K

Abstract:
1. A light interference system of measuring a thickness or a temperature of a measurement target object having a first main surface and a second main surface facing the first main surface, the light interference system comprising: a light source configured to emit a measurement light having a wavelength that transmits through the measurement target object; a coupler having multiple input terminals and multiple output terminals corresponding to the multiple input terminals, at least one of the multiple input terminals serving as a first input terminal configured to receive the measurement light from the light source; multiple first collimators respectively connected to the multiple output terminals of the coupler, each being configured to emit the measurement light to the first main surface of the measurement target object and to receive reflected lights from the first main surface and the second main surface; a transmission device provided at a side of the multiple input terminals except the first input terminal and configured to send the reflected lights from the multiple output terminals to the multiple output terminals again; a spectrometer connected to the first input terminal and configured to measure an interference intensity distribution that is an intensity distribution of the reflected lights from the first main surface and the second main surface, the interference intensity distribution being dependent on a wavelength; and a measurement unit connected to the spectrometer and configured to measure a thickness or a temperature of the measurement target object based on a waveform obtained by Fourier transform of the interference intensity distribution.