公开(公告)号：JP2001033213A

公开(公告)日：2001-02-09

申请号：JP2000173240

申请日：2000-06-09

Applicant: IBM

Inventor： GOULD CHRIS ,  MULLER PAUL K ,  PRAKASH JAI V C ,  VAN DEN BERG ROBERT

IPC: G01B11/00 ,  G03F7/20 ,  G03F9/00 ,  H01L21/027 ,  H01L21/66 ,  H05K3/46

Abstract: PROBLEM TO BE SOLVED: To enable a simple measurement with good cost efficiency to be performed by converting the image of a repeat overlay mark into a phase image by an image processor, and analyzing the phase difference between repeat overlay marks on different levels in overlay measurement. SOLUTION: A digitizer 43 digitizes a first photo to generate a first digitized image. The digitizer 43 digitizes a second photo to generate an image. A Fourier transformer 45 transforms the second digitized image to a second geometric spectrum or a phase image. A phase comparator 48 calculates a phae difference between the first and second geometric spectra to measure alignment between two levels on a wafer 33. The digitizer 43 generates respective digitized images from a first and second portions of the photo. A signal processor 45 transforms the first and second digitized images to first and second geometric spectra. The phase comparator 48 calculates a phase difference between two geometric spectra to execute alignment measurement.