Charged particle beam equipment with magnification correction

1. Charged particle beam equipment for irradiating an observed sample with a charged particle beam that is moved in a scanning motion in an X direction and a Y direction to obtain an image of the observed sample, the equipment comprising:

magnification error value calculating means which calculates magnification error values in the X direction and the Y direction by performing coordinate transformation in an FFT spatial domain; and

data-processing means for obtaining correction subject information from the observed sample and correcting it using the magnification error values,

wherein the coordinate transformation in the FFT spatial domain is performed by using a coordinate transformation expression,

wherein the coordinate transformation expression is derived by:

doing a rotation transform with rotation angle θ to an ideal coordinate system obtained by providing the FFT transformation to a standard size sample whose pattern direction of a periodic structure corresponds with the X direction or the Y direction of the image, the periodic structure having a known periodic pitch, and

applying a scaling transformation with magnification (mx, my) to the rotation transformed ideal coordinate system,

wherein the magnification error values are calculated by:

doing the FFT transformation to the image obtained by imaging the standard size sample, and

substituting structure information extracted from the coordinate system of the image in the FFT spatial domain into the coordinate transformation expression.

2. The charged particle beam equipment according to claim 1 , wherein the data-processing means comprises:

means for photographing the observed sample at an arbitrary magnification to generate a photographed image;

means for measuring a size of at least a part of the photographed image; and

means for correcting the result of measurement of the size by using a magnification error value corresponding to the arbitrary magnification.

3. The charged particle beam equipment according to claim 1 , wherein the data-processing means comprises:

means for photographing the observed sample at an arbitrary magnification to generate a photographed image; and

means for enlarging or reducing a size of the photographed image by using a magnification error value corresponding to the arbitrary magnification.

4. The charged particle beam equipment according to claim 1 , wherein the standard size sample comprises a single-crystal thin-film sample having a known crystal structure.

5. The charged particle beam equipment according to claim 1 , wherein the standard size sample comprises a sample that is made by artificially processing a material two- or three-dimensionally so as to provide it with a repetition pattern having a uniform size, wherein the size of the pattern is known.

6. Charged particle beam equipment for irradiating an observed sample with an electron beam that is moved in a scanning motion in an X direction and a Y direction so as to obtain an image of the observed sample, the equipment comprising:

magnification error value calculating means for storing magnification error values for the X direction and the Y direction by performing coordinate transformation in an FFT spatial domain; and

data-processing means for obtaining a scan waveform outputted by a scanning coil for the scanning of the observed sample and correcting the scan waveform using the magnification error values

wherein the coordinate transformation in the FFT spatial domain is performed by using a coordinate transformation expression,

wherein the coordinate transformation expression is derived by:

doing a rotation transform with rotation angle θ to an ideal coordinate system obtained by providing the FFT transformation to a standard size sample whose pattern direction of a periodic structure corresponds with the X direction or the Y direction of the image. the periodic structure having a known periodic pitch, and

applying a scaling transformation with magnification (mx, my) to the rotation transformed ideal coordinate system,

wherein the magnification error values are calculated by:

doing the FFT transformation to the image obtained by imaging the standard size sample, and

substituting structure information extracted from the coordinate system of the image in the FFT spatial domain into the coordinate transformation expression.

7. The charged particle beam equipment according to claim 6 , wherein the data-processing means controls the scan waveform for the X direction and the scan waveform for the Y direction independently for correction.

8. The charged particle beam equipment according to claim 6 , wherein the standard size sample comprises a single-crystal thin-film sample having a known crystal structure.

9. The charged particle beam equipment according to claim 6 , wherein the standard size sample comprises a sample that is made by artificially processing a material two- or three-dimensionally so as to provide it with a repetition pattern having a uniform size, wherein the size of the pattern is known.

10. A machine readable storage medium having stored therein a program for controlling charged particle beam equipment for irradiating an observed sample with an electron beam that is moved in a scanning motion in an X direction and a Y direction so as to obtain an image of the observed sample, the program comprising:

a program code for performing an information acquisition step for acquiring correction subject information from the observed sample being irradiated by the charged particle beam apparatus; and

a program code for performing a data-processing step for correcting the correction subject information using a magnification error value stored in magnification error value calculating means which calculates magnification error values for use in moving the electron beam the X direction and the Y direction by performing coordinate transformation in an FFT spatial domain, by doing the FFT transformation to the image obtained by imaging the standard size sample, and

substituting structure information extracted from the coordinate system of the image in the FFT spatial domain into the coordinate transformation expression,

wherein the coordinate transformation in the FFT spatial domain is performed by using a coordinate transformation expression, derived by:

doing a rotation transform with rotation angle θ to an ideal coordinate system obtained by providing the FFT transformation to a standard size sample whose pattern direction of a periodic structure corresponds with the X direction or the Y direction of the image, the periodic structure having a known periodic pitch, and

applying a scaling transformation with magnification (mx, my) to the rotation transformed ideal coordinate system.

11. The machine readable storage medium according to claim 10 , wherein the data-processing step comprises the steps of:

photographing the observed sample at an arbitrary magnification to generate a photographed image;

measuring the size of at least a part of the photographed image; and

acquiring a result of the measurement of the size by using a magnification error value corresponding to the arbitrary magnification.

12. The machine readable storage medium according to claim 10 , wherein the data-processing step comprises the steps of:

photographing the observed sample at an arbitrary magnification to generate a photographed image; and

enlarging or reducing a size of the photographed image by using a magnification error value corresponding to the arbitrary magnification.

13. A machine readable storage medium having stored therein a program for controlling charged particle beam equipment for irradiating an observed sample with an electron beam that is moved in a scanning motion in an X direction and a Y direction so as to obtain an image of the observed sample, the program comprising:

a program code for performing an information acquisition step for acquiring a scan waveform outputted by a scanning coil for the scanning of the observed sample; and

a program code for performing a data-processing step for correcting the scan waveform based on a magnification error value stored in magnification error value calculating means which calculates magnification error values for the X direction and the Y direction by performing coordinate transformation in an FFT spatial domain,

wherein the coordinate transformation in the FFT spatial domain is performed by using a coordinate transformation expression,

wherein the coordinate transformation expression is derived by:

doing a rotation transform with rotation angle θ to an ideal coordinate system obtained by providing the FFT transformation to a standard size sample whose pattern direction of a periodic structure corresponds with the X direction or the Y direction of the image, the periodic structure having a known periodic pitch, and

applying a scaling transformation with magnification (mx, my) to the rotation transformed ideal coordinate system, and

wherein the magnification error values are calculated by:

doing the FFT transformation to the image obtained by imaging the standard size sample, and

substituting structure information extracted from the coordinate system of the image in the FFT spatial domain into the coordinate transformation expression.

14. The machine readable storage medium according to claim 13 , wherein the data-processing step comprises controlling the scan waveform in the X direction and the scan waveform in the Y direction independently for correction.