Enhancing film measurement accuracy with calibration and correction techniques for a line-field Linnik white-light dispersive interferometer

White-light dispersive interferometry (WLDI) is an optical metrology technique that is used to measure precise and complex surfaces. However, the accuracy of spectral signal acquisition can affect the precision and subsequent evaluation of measurement results, particularly for the measurement of surface profiles and film thickness. We proposed a high-precision WLDI system, and a new method is introduced to correct various error sources in the system, including spectral distortion, objective lens mismatch, misalignment of optical components, and numerical aperture of the objective lens. This calibration method significantly enhances measurement accuracy in interferometry systems and closely aligns with manufacturing specifications. The experimental results show that this method can be applied to improve the high-accuracy simultaneous measurement of the profile and thickness of films.