Charged particle beam scanning method and charged particle beam apparatus
View Patent ↗In a method of scanning a charged particle beam which can position the scan position to a proper location inside a deflectable range of the scan position of charged particle beam, the scan position of charged particle beam is deflected to a plurality of target objects inside a scan position deflectable region and on the basis of a shift of a target object at a scan location after deflection, the deflection amount at the scan location is corrected.
1. A method of scanning a charged particle beam by deflecting the scan position of the charged particle beam through the use of a deflector to scan the charged particle beam, the method comprising the steps of:
positioning the scan of said charged particle beam to each of a plurality of target objects of a specimen in which said plurality of target objects are arranged at known distances from a reference target object;
deflecting the scan position of said charged particle beam so as to scan each of said plurality of target objects,
detecting an error in position between the scan position of said charged particle beam and each of the plurality of said target objects, and
on the basis of the plural position errors, deriving correction signals of said deflector to be used for scanning of the scan position of said charged particle beam.
2. A charged particle beam scanning method according to claim 1 , wherein said reference target object is positioned under an optical axis of said charged particle beam.
3. A charged particle beam scanning method according to claim 1 , wherein images of said reference target object and of said plurality of target objects are acquired by scanning said charged particle beam, and on the basis of a distance between a centroid of said reference target object and that of each of said target objects, a position error is detected.
4. A charged particle, beam scanning method according to claim 1 , wherein images of said reference target object and of said plurality of target objects are acquired by scanning said charged particle beam, and on the basis of a distance between said reference target object and each of said plural target objects obtained by performing pattern matching between them, a position error is detected.
5. A charged particle beam scanning method according to claim 1 , wherein said plurality of target objects are arranged two-dimensionally at intervals of known spacings on said specimen.
6. A charged particle beam scanning method according to claim 1 , wherein said position error is determined by adding or subtracting movement components of a movement stage for moving said specimen.