Patent ID: 7241996

Claim:
A charged particle beam apparatus for obtaining an image by irradiating a charged particle beam on a specimen and detecting a generation signal inclusively indicative of secondary electrons generated from the specimen, comprising: input means for inputting current and voltage values to be applied to a charged particle optical system through which said charged particle beam travels; apparatus parameter memory means for storing shape, position and physical properties of said charged particle optical system and accuracy of the applied current or voltage; electromagnetic field calculation means for calculating an electromagnetic field near a charged particle beam path; charged particle trajectory calculation means for calculating a trajectory of said charged particle beam in the calculated electromagnetic field; a central controller for implementing comparison and judgment between an optical condition obtained by simulation and an optical condition at image acquisition; optical condition memory means for storing a result of the trajectory calculation; and a controller for controlling said charged particle optical system on the basis of the result of the trajectory calculation; wherein the central controller repeats operations to be implemented by said input means through the comparison and judgment.