Charged particle beam apparatus and alignment adjustment method of sample stage

1. A charged particle beam apparatus comprising:

a movable stage on which a sample table capable of holding a sample is placed;

an irradiation optical system that irradiates the sample with a charged particle beam;

a detector that detects a signal emitted from the sample;

a display device that displays a charged particle image formed based on the signal;

an optical microscope configured to obtain an optical image of the sample table; and

a processor configured to control movement of the moveable stage to perform alignment of the sample table based on (i) a first processed optical image at a first magnification of the optical image of the sample table and (ii) a second processed optical image at a second magnification of the optical image of the sample table by aligning a visual display of the sample table with the second processed optical image using an alignment point designation with respect to a plurality of feature points on the sample as an alignment point,

wherein the second magnification is higher than the first magnification,

wherein the first processed optical image based on the first magnification of the optical image obtained by imaging the sample table using the optical microscope includes an indicator for sample table alignment with respect to an outer shape of the sample table, said first processed optical image being obtained by zooming and/or shifting the optical image of the sample table imaged by the optical microscope, and

wherein the processor is configured to perform a first alignment adjustment of the sample table by aligning the visual display of the sample stage with said first processed optical image using the indicator with respect to the outer shape of the sample table as another alignment point, and to perform a second alignment adjustment of the sample table based on the alignment point designation of said second processed optical image by zooming and/or shifting the optical image of the sample table obtained by imaging the sample table using the optical microscope and on the charged particle image, such that the processor performs the alignment of the sample table with respect to the indicator by aligning the visual display of the sample stage with said first processed optical image at said first magnification and with respect to said alignment point designation of said second processed optical image at said second magnification so that the alignment of the sample table with respect to the first processed optical image is adjusted with reference to both the outer shape of the sample table and the feature points on the sample.

2. The charged particle beam apparatus according to claim 1 , wherein the second alignment adjustment is performed after the first alignment adjustment is performed.

3. The charged particle beam apparatus according to claim 1 , wherein the first and/or the second processed optical image is formed by zooming the optical image imaged by the optical microscope and thereafter shifting the zoomed image.

4. The charged particle beam apparatus according to claim 1 , wherein in a case where a plurality of sample tables are placed on the stage, the first and/or the second alignment adjustment is performed for each sample table.

5. The charged particle beam apparatus according to claim 4 , wherein in a case where a predetermined sample table among the plurality of sample tables is selected, the stage moves based on the first and/or second alignment adjustment of the sample table.

6. An alignment adjustment method in a charged particle beam apparatus that includes a movable stage on which a sample table capable of holding a sample is placed, an irradiation optical system that irradiates the sample with a charged particle beam, a detector that detects a signal emitted from the sample, a display device that displays a charged particle image formed based on the signal, and an optical microscope that images the sample table, the method comprising:

displaying an indicator for sample table alignment with respect to an outer shape of the sample table on a first processed optical image, the first processed optical image being obtained by zooming and/or shifting an optical image imaged by the optical microscope;

performing a first alignment adjustment of the sample table with respect to the first processed optical image using the indicator of the first processed optical image as an alignment point;

displaying an alignment point designation on a second processed optical image obtained by zooming and/or shifting the optical image obtained by imaging the sample table using the optical microscope and on the charged particle image; and

performing a second alignment adjustment of the sample table by aligning a visual display of the sample table with the second processed optical image using the alignment point designation on the second processed optical image as another alignment point so that the alignment of the sample table with respect to the first processed optical image is adjusted with reference to both the outer shape of the sample table and a plurality of feature points on the sample.

7. The alignment adjustment method according to claim 6 , wherein the second alignment adjustment is performed after the first alignment adjustment is performed.

8. The alignment adjustment method according to claim 6 , wherein the first and/or the second processed optical image is formed by zooming the optical image imaged by the optical microscope and thereafter shifting the zoomed image.

9. The alignment adjustment method according to claim 6 , wherein in a case where a plurality of sample tables are placed on the stage, the first and/or second alignment adjustment is performed for each sample table.

10. The alignment adjustment method according to claim 9 , wherein in a case where a predetermined sample table among the plurality of sample tables is selected, the stage moves based on the first and/or second alignment adjustment of the sample table.