公开(公告)号：DE2860511D1

公开(公告)日：1981-04-02

申请号：DE2860511

申请日：1978-12-22

Applicant: IBM

Inventor： DAVIS DONALD EUGENE ,  WEBER EDWARD VICTOR ,  WILLIAMS MAURICE CARMEN ,  WOODARD OLLIE CLIFTON

IPC: G01B15/00 ,  H01J37/304 ,  H01L21/027 ,  H01L21/302 ,  H01J37/30 ,  H01L21/66

Abstract: A method and apparatus is described for performing automatic overlay measurements on wafers utilized in semiconductor manufacturing. The overlay measurements are made at selected sites on a given wafer where a single bar pattern has been overlaid over a double bar pattern. The position of the single bar center line with respect to the center line between the double bars is a direct indication of the overlay error of the two patterns. The overlay error is measured in both the X and Y dimensions and is utilized to monitor the overlay error or to produce statistics and correlations to system parameters so that the sources of overlay errors may be identified and the errors eliminated or minimized on subsequent wafers being processed.