Patent ID: 6509564
Filing Date: 2003-01-21
Classification: H01J

Abstract:
A circuit pattern inspecting apparatus comprising:an irradiation optical system for converging a primary charged particle beam while deflecting said primary charged particle beam so as to scan a circuit pattern of a workpiece with said primary charged particle beam; a retarding/accelerating means for retarding said primary charged particle beam, and accelerating secondary charged particles produced from said workpiece by the irradiation of said workpiece with said primary charged particle beam and reflection particles reflected from said workpiece; a workpiece stage for holding said workpiece; a sensor for measuring the surface height of an irradiated position of said workpiece with said primary charged particle beam; a detector for detecting said secondary charged particles produced from said workpiece; an image forming means for forming an image of the irradiated region of said workpiece from a signal detected by said detector; an outer peripheral sample having outer peripheral standard marks formed on at least two surfaces different in thickness in the direction of the axis of said primary charged particle beam, said outer peripheral sample being provided at an outer peripheral portion of a substrate mounting area of said workpiece stage; a central sample having central standard marks formed on at least two surfaces different in thickness in the direction of the axis of said primary charged particle beam, said central sample being provided at a central portion of the substrate mounting area of said workpiece stage; a storing means for storing image signals obtained from said outer peripheral standard marks of said outer peripheral sample and said central standard marks of said central sample; a computing means for computing a distortion amount of said primary charged particle beam inherent to said outer peripheral portion from said outer peripheral and central standard mark image signals; an eliminating means for eliminating said distortion amount inherent to said outer peripheral portion from said outer peripheral standard mark image signals; a storing means for preparing a deflection correcting table corresponding to the height of said workpiece on the basis of said outer peripheral standard mark image signals from which said distortion amount has been eliminated, and storing said deflection correcting table; a deflection correcting signal generating circuit for obtaining a deflection correcting signal from said deflection correcting table in accordance with the surface height signal from which said distortion amount has been eliminated obtained by said sensor; and a control means for controlling irradiation of said outer peripheral sample having said outer peripheral standard marks at a desired timing to update said deflection correcting table.