Polymer Film Thickness Determination with a High-Precision Scanning Reflectometer

Abstract

A fiber-optic-based optical low coherence reflectometer (OLCR) is used to measure the thickness of polyester films. The measurements are made on both stationary and moving films to show the feasibility of this technique in a process environment. Autocorrelation is used to extract useful data from raw reflectometry data, and a statistical analysis of the data from both moving and stationary films is done to help demonstrate the application of this method. Although the reflectometer is not optimally configured for process analysis, a reliable estimate of polymer film thickness is shown in less than one minute measurement time for the moving films.