公开(公告)号：US20040016897A1

公开(公告)日：2004-01-29

申请号：US10289005

申请日：2002-11-05

Applicant: KLA-Tencor Technologies Corporation

Inventor： Stan Stokowski ,  Damon F. Kvamme ,  Chun Shen Lee ,  Donald W. Pettibone

IPC: G01N021/88 ,  H01J005/16

CPC classification number: G03F1/84 ,  G01N21/95607 ,  G01N2021/95676

Abstract: Provided are apparatus and methods for detecting phase defects. The invention relies generally on the distortion of light as it passes through defects in phase shift masks to detect these defects. Light traveling through a defect, such as a bump in an etched area will travel at a different angle than light traveling through air. In order to enhance the signals generated from the defects, the invention in several embodiments provides a multiple element detector having at least four elements, arranged in a radially symmetric configuration. Individual elements of the detector are selected to form a differential signal based on the configuration of pattern lines in the area proximate to the defect. The resulting differential signal is used to generate an image signal and to identify phase defects.