Patent ID: 7244933

Claim:
A pattern evaluation method for evaluating patterns formed on a sample, comprising: a) a step of advancing an electron beam emitted from an electron gun along a primary optical system formed normal to the sample; b) a step of deflecting said electron beam toward a beam separator by a deflector; c) a step of deflecting said electron beam by an angle of α to one direction by an electrostatic deflector of said beam separator and further deflecting said electron beam by an angle of 2α a to the opposite direction by an electromagnetic deflector of said beam separator whereby said electron beam is resultantly deflected to the opposite direction by an angle of α as a difference between said two deflections; d) a step of focusing said primary beam on said sample by an objective lens; e) a step of deflecting secondary electrons emanated from said sample to detectors by said beam separator after having passed through said objective lens; and f) detecting said secondary electrons by said detectors and evaluating a sample image.