Patent ID: 6864493

Claim:
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 an objective lens to two states when a deflection condition of an alignment deflector is rendered to a first state; detecting a first two dimensional deviation between first and second sample images obtained when the deflection condition of said alignment detector 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 two dimensional deviation between third and fourth sample images obtained when the deflection condition of said alignment detector is rendered to the second state; calculating an unknown changing depending on a condition of said charged particle beam optical apparatus by applying information of the first and second two dimensional deviations to an equation indicating the relation of an alignment condition and deviation of the sample images; 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 varies.