Pattern inspection apparatus with corner rounding of reference pattern

Abstract

A pattern inspection apparatus for comparing/collating a test target pattern with a corresponding design pattern to detect the presence/absence of a defect which is present in the test target pattern includes a bit pattern generating circuit for developing the data of the design pattern into bits, a corner pattern detector for scanning a corner pattern detection window having a predetermined range with respect to reference pattern data as a reference of a pattern obtained by bit development performed by the bit pattern generating circuit to extract a contour pattern, and detecting a corner pattern to be subjected to corner rounding processing on the basis of the extracted contour pattern, a memory for storing predetermined change information corresponding to the corner detected by the corner pattern detector, a graphic pattern synthesizing circuit for changing a graphic pattern in accordance with the information in the memory, and a comparing circuit for comparing reference pattern data, obtained by rounding processing performed on the basis of the reference pattern data and the feature of the corresponding pattern, with test pattern data obtained from the test target pattern, and further includes a pattern correcting circuit constituted by an excessive rounding detector for detecting and correcting an inadequate excessive rounding operation, and a pattern changing circuit for changing the pattern data in accordance with the excessive rounding detection result.