AUTOMATED-ANALYSIS OF FOURIER IMAGES FOR SEMICONDUCTOR WAFER MONITORING

A method for automating the analysis of images generated from the Fourier imaging (FI) process is described. Fourier imaging is used to observe the evolving topography of wafers as they are being etched in a reactive ion etcher. The focus of the research described in this paper is the segmentation and analysis of images generated from FI. A brief overview of the theory of FI is presented. Segmentation of a Fourier image is done in three steps; local maxima detection, Fourier component extent identification, and boundary tracking. Quantification descriptions for each component are then generated from the segmented image. The algorithm presented demonstrates how it is possible to obtain subpixel resolution automatically in image analysis to collect data that may be used to compute critical dimensions of the microtopography of the wafer substrate.