Fast and Accurate Film Thickness Measurement for Semiconductor Wafers Based on Centroid Wavelength Analysis and Dense CRF Refinement

Fast and accurate measurement of thin film thickness across semiconductor wafers is critical for improving production efficiency. Conventional spectral interferometry achieves nanometer-scale precision but requires over an hour for processing due to extensive spectral data acquisition and analysis. This paper proposes a rapid measurement method using only the centroid wavelength (CWL) of the reflected spectrum, eliminating the need to process full spectral distributions. Three CWL images are captured using a λ-Capture® camera under different illumination spectra, and film thickness is determined via maximum a posteriori estimation. To suppress measurement errors from local instabilities, we introduce a dense CRF-based optimization model based on spatial continuity in the CWL images. Experiments on 8-inch wafers demonstrate that our method reduces processing time from 88 minutes to under 3 seconds while achieving measurement accuracy with error rates below 1%, meeting practical semiconductor manufacturing requirements across film thicknesses of 200-800 nm.