METHODS AND SYSTEMS FOR IMPROVED LOCALIZED FEATURE QUANTIFICATION IN SURFACE METROLOGY TOOLS

摘要

A method for enabling more accurate measurements of localized features on wafers is disclosed. The method includes: a) performing high order surface fitting to more effectively remove the low frequency shape components and also to reduce possible signal attenuations commonly observed from filtering; b) constructing and applying a proper two dimensional LFM window to the residual image from the surface fitting processing stage to effectively reduce the residual artifacts at the region boundaries; c) calculating the metrics of the region using the artifact-reduced image to obtain more accurate and reliable measurements; and d) using site-based metrics obtained from front and back surface data to quantify the features of interest. A method for filtering data from measurements of localized features on wafers is disclosed. This method includes an algorithm designed to adjust the filtering behavior according to the statistics of extreme data samples. A method for utilizing the 2D window and the data filtering to yield a more robust and more accurate Localized Feature quantification methodology is disclosed.