In semiconductor and Micro-Electro-Mechanical Systems production, thick resist films are indispensable for circuit formation, chemical mechanical planarization, or wafer-level packaging applications. We investigate multiple metrology protocols that aim at meeting the needs for fast, accurate, full-wafer determination of the thickness of up to 100 mu m thick resist layers deposited on silicon or glass wafers. We found very effective to use a two-step strategy consisting of: i/an accurate determination of the optical characteristics of the photoresist based on prism-coupling technique, and ii/the fast, full-wafer measurement of the wafers of interest, using high resolution spectroscopic reflectometry (SR). The robustness of this strategy increasedwhen analyzing the SR data with a Fourier transform (FT) based algorithmwhich combines FT-based filtering around the thickness of interest with spectral matching to improve measurement performance. (C) 2014 Elsevier B.V. All rights reserved.