Charged particle beam adjusting method and charged particle beam apparatus

Abstract

In an apparatus for obtaining an image by irradiating a charged particle beam on a specimen, a condition of the beam conditioned differently from vertical incidence as in the case of the beam being tilted is required to be adjusted. To this end, the apparatus has a controller for automatically controlling a stigmator, an objective lens and a deflector such that astigmatism is corrected, focus is adjusted and view filed shift is corrected. The controller has a selector for inhibiting at least one of the astigmatism correction, focus adjustment and FOV shift correction from being executed.

1 - 9 . (canceled) 
   
   
       10 . A charged particle beam adjusting method for performing astigmatism correction of a charged particle beam using a stigmator capable of adjusting intensities of astigmatism correction in a plurality of directions when the charged particle beam is irradiated while being titled in relation to an optical axis of an objective lens, comprising the steps of:
 acquiring images corresponding to individual combinations of the intensities of astigmatism correction in the plurality of directions;   determining an evaluation value of each of the images in respect of the individual combinations; and   determining combination of intensities of astigmatism correction to be set by the stigmator on the basis of a combination of intensities of astigmatism correction for which the evaluation value is high.   
   
   
       11 . A charged particle beam adjusting method according to  claim 10 , wherein the images acquiring step is executed within a predetermined range of magnification. 
   
   
       12 . A charged particle beam apparatus comprising:
 a charged particle beam source;   an objective lens for focusing a charged particle beam emitted from said charged particle beam source so as to irradiate it on a specimen;   a detector for detecting charged particles emitted from the specimen;   a deflector for deflecting the charged particle beam to a region which is out of axis of said objective lens and tilting the charged particle beam in relation to an optical axis of said objective lens;   a stigmator capable of adjusting intensities of astigmatism correction in a plurality of directions; and   a controller for acquiring images corresponding to individual combinations of intensities of astigmatism correction which are adjusted in the plurality of directions, determining evaluation values of the images corresponding to the individual combinations, and setting a combination of intensities which are adjusted by the stigmator on the basis of a combination of intensities for which the evaluation value is high.   
   
   
       13 . A charged particle beam apparatus according to  claim 12 , wherein said controller acquires the images within a predetermined range of magnification. 
   
   
       14 . A charged particle beam apparatus according to  claim 12 , wherein:
 said controller acquires the images corresponding to individual first combinations of intensities of astigmatism correction in one direction of X-axis and intensities of astigmatism correction in another direction of Y-axis, on a two-dimensional region formed by the X-axis and the Y-axis, and   when a combination of the first combinations of intensities for which the evaluation value is high exists at an edge of the first combinations, said controller sets a combination of intensities on the basis of a plurality of combinations on the two-dimensional region in which a center combination of the plurality of second combinations corresponds to the edge of the first combinations.   
   
   
       15 . A charged particle beam apparatus according to  claim 14 , wherein said controller executes additional acquisition of an image of a combination in the second combinations in which any images are not acquired. 
   
   
       16 . A charged particle beam apparatus according to  claim 12 , wherein said plurality of directions are two directions of a X-direction and a Y-direction.