Charged particle beam apparatus, charged particle beam focusing method, microstructure measuring method, microstructure inspecting method, semiconductor device manufacturing method, and program

Abstract

A charged particle beam apparatus includes: a charged particle source which generates a charged particle beam to apply to a specimen having a microstructure formed on a surface thereof; an objective lens which excites at least one of an electric field and a magnetic field to converge the charged particle beam onto the specimen; a deflector which scans the specimen with the charged particle beam; a detector which detects at least one of a secondary charged particle, a reflection charged particle and a back scattering charged particle generated from the specimen and which outputs a detection signal; a focusing area arranging unit which arranges a plurality of focusing areas including edge points of the microstructure therein in a surface area of the specimen; a deflection controller which controls the deflector so that the focusing areas are sequentially scanned to correspond to excitation conditions while changing stepwise the excitation conditions of the objective lens; a focus calculator which calculates an index indicating a convergence state in each excitation condition on the basis of the detection signal and which calculates an optimum excitation condition providing an optimum focal position from the index; and an objective lens controller which drives the objective lens under the optimum excitation condition.