Patent ID: 8563926
Filing Date: 2013-10-22
Classification: H01J

Abstract:
1. A method of making axial alignment of a charged particle beam in a charged particle beam system for adjusting the axis of the beam by a first alignment coil that deflects the beam in a first direction and a second alignment coil that deflects the beam in a second direction crossing the first direction, irradiating a sample with the beam, detecting a signal emanating from the sample, and obtaining image data, said method comprising the steps of: obtaining at least first through sixth image data while varying acquisition conditions including a focal position of the beam on the sample in a direction of incidence, an excitation current in the first alignment coil, and an excitation current in the second alignment coil; and calculating a value of the excitation current in the first alignment coil and a value of the excitation current in the second alignment coil for the axial alignment of the beam from the at least first through sixth image data obtained by the step of obtaining the image data; wherein during said step of obtaining the at least first through sixth image data, said first image data is obtained under conditions where said focal position is a first position, the value of the excitation current in said first alignment coil is a first electric current value, and the value of the excitation current in said second alignment coil is a second electric current value, said second image data is obtained under conditions where the focal position is a second position, the value of the excitation current in the first alignment coil is the first electric current value, and the value of the excitation current in the second alignment coil is the second electric current value, said third image data is obtained under conditions where the focal position is the first position, the value of the excitation current in the first alignment coil is the first electric current value, and the value of the excitation current in the second alignment coil is an electric current value obtained by varying the second electric current value by a first incremental current value, said fourth image data is obtained under conditions where the focal position is the second position, the value of the excitation current in the first alignment coil is the first electric current value, and the value of the excitation current in the second alignment coil is an electric current value obtained by varying the second electric current value by the first incremental current value, said fifth image data is obtained under conditions where the focal position is the first position, the value of the excitation current in the first alignment coil is an electric current value obtained by varying the first electric current value by the first incremental current value, and the value of the excitation current in the second alignment coil is the second electric current value, and said sixth image data is obtained under conditions where the focal position is the second position, the value of the excitation current in the first alignment coil is an electric current value obtained by varying the first electric current value by the first incremental current value, and the value of the excitation current in the second alignment coil is the second electric current value.