A position recognition algorithm for semiconductor alignment based on structural pattern matching

The authors propose a position recognition algorithm that can be used for future automated production of high-density semiconductor devices. It consists of a position detection method based on a pattern structure which is expressed as the distribution of characteristic local patterns, and an adaptive thresholding method based on an evaluation index which represents the binary state of characteristic local patterns. The validity and effectiveness of the algorithm are confirmed by experimentation with actual semiconductor chip patterns. High-speed processing of the algorithm is possible by using an image processor with simple matching hardware