Electron microscope

Abstract

An electron microscope is provided, which enables an observation with high resolution. The electron microscope is able to detect the deviation of an electron beam relative to the opening of a slit quantitatively, thereby shifting the electron beam accurately to the center of the opening of slit so as to execute energy selection. The electron microscope has an energy filter control unit for adjusting a relative position between an electron beam and a slit by shifting the position of electron beam based on a signal delivered by an energy filter electron beam detector. Also a method for controlling an energy filter is provided, which includes the steps of shifting the position of an electron beam, determining the position of electron beam and letting the electron beam pass through the center of an opening of the slit by controlling the position of slit or position of electron beam.

1 - 10 . (canceled)  
   
   
       11 . An energy filter for selecting an electron beam having a required range of energy levels comprising: 
 an energy dispersion section for dispersing an electron beam according to energy levels;    a slit for selecting the electron beam dispersed by the energy dispersion section; and    an energy filter control unit for adjusting a relative position between the slit and the electron beam;    wherein when an electron beam is applied, which conducts a reciprocating motion on the slit, the energy filter control unit adjusts the relative position according to an electron beam which has passed through the slit.    
   
   
       12 . An energy filter according to  claim 11 , wherein the reciprocating motion is a cyclical motion carried out relative to a center position on which an electron beam without adjustment illuminates.  
   
   
       13 . An energy filter according to  claim 11 , wherein the slit is disposed at a position on which the electron beam dispersed by the energy dispersion section illuminates and an electron beam does not illuminate when dispersion is not carried out by the energy dispersion section.  
   
   
       14 . An energy filter according to  claim 11 , wherein the energy filter is disposed in one of upstream and downstream of a specimen relative to a direction of traveling of an electron beam.  
   
   
       15 . A method for adjusting a position of one of an energy filter which selects an electron beam having a required range of energy levels, a slit and an electron beam applied to the slit, the method comprising the steps of: 
 guiding an electron beam into an energy dispersion section for dispersing the electron beam according to energy levels;    applying the electron beam dispersed by the energy dispersion section to the slit; and    adjusting a relative position between the slit and the electron beam according to intensity of an electron beam which has passed through the slit;    wherein applying the electron beam comprises controlling one of the electron beam and the slit so that the electron beam carries out an reciprocal motion on the slit.    
   
   
       16 . A method for adjusting a position of one of an energy filter which selects an electron beam having a required range of energy levels, a slit and an electron beam applied to the slit, wherein the energy filter comprises an energy dispersion section for dispersing an electron beam according to energy levels and a slit having a gap which is formed by at least a first shield and a second shield, the method comprising the steps of: 
 repeating shifting of a position of an electron beam on the slit at least once from a first position where the electron beam is intercepted by the first shield, via the gap, to a second position where the electron beam is intercepted by the second shield; and    controlling the position of the electron beam according to a change of intensity of an electron beam passing through the slit.    
   
   
       17 . A method according to  claim 15 , prior to guiding the electron beam into the energy dispersion section, the method further comprising the step of: adjusting coarsely one of the slit, the energy dispersion section and a trajectory of an electron beam so that the electron beam is positioned on the slit.