Scanning charged-particle beam instrument

A scanning charged-particle beam instrument comprising:

• a specimen stage assembly including a combination of an X-Y stage for translation along X and Y axes and a rotating stage, said rotating stage having a center of rotation about a third axis;
• means for directing a charged-particle beam to a specimen placed on said specimen stage assembly generally along the third axis;
• means for scanning said charged-particle beam in two dimensions across said specimen;
• a detector for detecting signals arising from said specimen;
• means for displaying a scanned image of said specimen on a viewing screen in response to an output signal from said detector;
• storage means in which amounts of correction made to X and Y coordinates of said X-Y stage to cause said scanned image to be rotated about the center of said viewing screen when said rotating stage is mechanically rotated are stored together in a table with corresponding angular positions of said rotating stage for different X and Y coordinates of the center of rotation of said rotating stage;
• and
• means for prior to a given rotation reading said amounts of correction from said storage means according to the X and Y coordinates of the center of rotation of said rotating stage at the beginning of a rotation and according to the angle of the given rotation.