Identification Number Recognition System for a Semiconductor Wafer Using the Generalized Hough Transform

Abstract

Semiconductor wafers are usually provided with identification information such as product numbers, manufacturing numbers and lot numbers by making. Such identification number is read, recognized, and used for various purposes, such as automatic control of manufacturing procedures, sorting of products, and quality control. System and method using the generalized Hough transform are developed to recognize wafer identification number. A template table which stores edge point parameters to be used for the generalized Hough transform is compressed so as to include only predetermined parameters, and is then divided into a plurality of template tables. Divided template tables are respectively loaded in the memories of a plurality of subprocessors operating in parallel under the control of a main processor. In performing recognition processing, these subprocessors operate in parallel according to their related partial template tables. Identification number recognition using the generalized Hough transform provides a high rate of recognition. Also, parallel processing using the compressed template tables and partial template tables helps shorten table search time and computation time, thereby increasing processing efficiency. © 1995, The Japan Society for Precision Engineering. All rights reserved.