A scan control unit for generating two-dimensional coordinates for performing a scan with an electron beam of an electron scanning microscope is provided with first and second transforming units for transforming coordinates in the horizontal (X) direction and the vertical (V) direction. An area to be tested in a sample is scanned with an electron beam in an arbitrary direction. As the first and second transforming units, small-capacity transformation tables (LUTs) capable of operating at high speed in each of the horizontal (X) direction and the vertical (Y) direction are used. By also using a large-capacity transformation table (LUT) that stores coordinate transformation data corresponding to plural scan types, a test apparatus compatible with the plural scan types, having multiple functions, and capable of performing high-speed scan control is realized.
1. An apparatus comprising:
irradiating means for performing a scan in an arbitrary direction to irradiate discrete positions on a subject with an electron beam;
detecting means for sequentially detecting secondary electrons released from the discrete positions on the subject irradiated with the electron beam;
image processing means for sorting image data based on signals of the detected secondary electrons;
display means for displaying the sorted image data; and
scan control means for generating a signal for controlling the irradiating means;
wherein the scan control means has a coordinate transforming unit for transforming coordinates in each of a horizontal direction and a vertical direction.
2. The apparatus according to claim 1 , wherein the scan control means has a transformation table that stores transformation data by a plurality of scan types.
3. An apparatus comprising:
irradiating means for performing a scan in an arbitrary direction to irradiate discrete positions on a subject with an electron beam;
detecting means for sequentially detecting secondary electrons released from the discrete positions on the subject irradiated with the electron beam;
image processing means for sorting image data based on signals of the detected secondary electrons;
display means for displaying the sorted image data; and
scan control means for generating a signal for controlling the irradiating means;
wherein the scan control means has a coordinate transforming unit for transforming coordinates in each of a horizontal direction and a vertical direction and a transformation table that stores transformation data by a plurality of scan types; and
wherein a capacity of the transformation table is larger than a capacity of the coordinate transforming unit.