Fig. 1. Principle of the proposed method. (a) Flowchart of the phase noise suppression method based on multi-period moving difference; (b) basic principle of moving sine fitting; (c) example of envelope and carrier phase calculation based on FFT

Fig. 2. Basic principle of Mirau type white light interference. (a) Mirau type white light interferometric optical path; (b) Mirau objective structure; (c) experimental equipment

Fig. 3. Measured data of Mirau-type white light interferometry. (a) Intensity and wrap phase distribution of the measured white light interferometer single-point signal; (b) carrier phase deviation before and after denoising of measured signals

Fig. 4. Denoising effect of the proposed method on the original measurement signal. (a) Intensity of the denoised signal; (b) distribution of phase noise before and after denoising

Fig. 5. Measurements results of step sample topography and profile outline. (a)(b) Proposed; (c)(d) FDA method; (e)(f) FFT-WLPSI

Fig. 6. Denoising effect of the proposed method on the measured etch slot signal. (a) Intensity of denoised signal; (b) distribution of phase increment before and after denoising

Fig. 7. Measurement results of the topography and profile of the inner etched groove step. (a) Proposed; (b) FDA method; (c) FFT-WLPSI; (d) profile comparison along Y=1000

Fig. 8. Topography and profile extraction results of the microlens array. (a) Proposed; (b) FFT-WLPSI method; (c) FDA method; (d) One-dimensional profiles obtained by three methods along X=521 pixel