Patent ID: 7209584

Claim:
A pattern inspection apparatus which inspects a pattern formed on a plate, comprising: a pattern data generator configured to generate measured pattern data regarding the pattern on the plate; a memory which stores first design data and second design data, the first designed data representing an opaque pattern including a first alignment mark and the second designed data representing a phase shifting pattern including a second alignment mark; a control computer configured to control extraction of a first inspection area and a second inspection area, the first inspection area having a predetermined width from one of the first design data and the second design data, the second inspection area being obtained by correcting a designed position of one of the first alignment mark and the second alignment mark by a difference between a measured data difference and a designed data difference with respect to the other of the first designed data and the second designed data, the measured data difference concerning a difference of respective measured data of the first alignment mark and the second alignment mark which are obtained based on the measured pattern data, and the designed data difference concerning a difference of respective designed data of the first alignment mark and the second alignment mark; a bit pattern data generator configured to provide first bit pattern data obtained by converting said one of the first design data and the second designed data included in the first inspection area to a two-dimensional image data configured of squares comprising bit components, and second bit pattern data obtained by converting the other of the first design data and the second designed data included in the second inspection area to another two-dimensional image data configured of squares comprising bit components; reference pattern data generator configured to generate reference pattern data by performing combining and filtering of the first bit pattern data and the second bit pattern data; and a comparator configured to compare the reference pattern data with the measured pattern data to inspect a defect of the pattern on the plate.