Charged particle beam alignment method and charged particle beam apparatus

Abstract

An object of the present invention is to provide a charged particle beam apparatus and an alignment method of the charged particle beam apparatus, which make it possible to align an optical axis of a charged particle beam easily even when a state of the charged particle beam changes. The present invention comprises calculation means for calculating a deflection amount of an alignment deflector which performs an axis alignment for an objective lens, a plurality of calculation methods for calculating the deflection amount is memorized in the calculation means, and a selection means for selecting at least one of the calculation methods is provided.

1 . A charged particle beam alignment method which performs an axis alignment for a lens and uses a charged particle beam apparatus having a lens for converging a charged particle beam emitted from a charged particle source and forming a sample image by detecting secondary charged particles emitted from a sample by radiating the charged particle beam onto the sample converged by the lens, the method comprising the steps of:
 changing a convergence condition of said objective lens to two states when a deflection condition of said alignment deflector is rendered to a first state;   detecting a first deviation between first and second sample images obtained when the deflection condition of said alignment deflector is rendered to the first state;   changing the convergence condition of said objective lens to at least two states when the deflection condition of said alignment deflector is rendered to a second state;   detecting a second deviation between third and fourth sample images obtained when the deflection condition of said alignment deflector is rendered to the second state;   calculating an unknown changing depending on an operation condition of said charged particle beam optical system by applying information of the first and second deviations to an equation finding the deviation of the sample image relative to a change of an alignment condition; and   obtaining the alignment condition based on the calculated unknown and a condition in which an image deviation becomes small when the convergence condition of the objective lens is changed to the two condition.   
   
   
       2 .- 23 . (canceled)