Spectrum Calibration and Processing Research of Thin-Film Thickness Wideband Monitoring System

In thin-film thickness wideband monitoring system, the monitoring effectiveness depends on the real- time and accurate measurement of the spectrum. To achieve the correct spectral signal in real-time, by analyzing the configuration of the spectrometer, the proper slit width of 0.14 mm was determined, the spectrum calibration function was achieved; The strong background noise was eliminated by subtracting the signal in the dark state from the signal in the adjacent bright state to the same pixel; the random noise was suppressed by the wavelet threshold optimization algorithm. Experimental result showed that the spectral resolution was less than 2 nm and the root-mean-square error of the wavelength calibrated was 0.037 nm; Background noise and random noise were well suppressed and the details of the spectrum signal were reserved, maximum of the peak error and the peak location of the spectral signal was 1.0 % and 0.3 % respectively. This improves the monitoring accuracy, thin film thickness monitoring error is less than 10 -3 . Copyright © 2014 IFSA Publishing, S. L.