A New Algorithm for Reticle Inspection

Wafer steppers have widely used for fine line delineation for VLSI processing. In order to increase patterning yield, any defects in the reticle pattern must be inspected precisely. Currently, various reticle inspection apparatuses are commercially available [1,2,3]. Their inspections are performed by firstly converting of an optically detected pattern to a two-level pattern (0 or 1 signal) and then comparison of it with a designed data (e.g. EB data). However, the method has such drawbacks as (i) difficulty in detecting halftone defects, (ii) detection limit is defined by its pixel size and (iii) alignment error between the pixel of sensed data and that of designed data.