Sample height regulating method, sample observing method, sample processing method and charged particle beam apparatus
View Patent ↗In a sample height regulating method, an area including the observation point on the sample is scan-irradiated with a first charged particle beam to obtain a first secondary electron image including the observation point. An area including the observation point on the sample is then scan-irradiated with a second charged particle beam to obtain a second secondary electron image including the observation point. Thereafter, based on magnifications of the first secondary electron image and the second secondary electron image and a distance between the observation point in the first secondary electron image and the observation point in the second secondary electron image, a height of the sample required for focusing the first charged particle beam and the second charged particle beam on the observation point is calculated. A sample stage supporting the sample is then displaced so as to position the sample at the calculated sample height.
1. A sample height regulating method for irradiating an observation point on a sample with two charged particle beams from different angles, comprising the steps of:
scan-irradiating an area including the observation point on the sample with a first charged particle beam to obtain a first secondary electron image including the observation point;
scan-irradiating an area including the observation point on the sample with a second charged particle beam to obtain a second secondary electron image including the observation point;
calculating, based on magnifications of the first secondary electron image and the second secondary electron image and a distance between the observation point in the first secondary electron image and the observation point in the second secondary electron image, a height of the sample required for focusing the first charged particle beam and the second charged particle beam on the observation point; and
displacing a sample stage so as to position the sample at the calculated sample height.
2. A sample observing method comprising the steps of:
executing a sample height regulating method according to claim 1 at a desired observation area or in a vicinity thereof; and
scan-irradiating the observation area or the vicinity thereof with the first charged particle beam to obtain a secondary electron image of the observation area.
3. A sample height regulating method according to claim 1 ; wherein the first charged particle beam is an electron beam and the second charged particle beam is an ion beam.
4. A sample processing method comprising the steps of:
executing a sample height regulating method according to claim 3 at a desired process area or in a vicinity thereof; and
scan-irradiating the process area or the vicinity thereof with the ion beam to etch the process area.
5. A sample processing method comprising the steps of:
executing a sample height regulating method according to claim 3 at a desired process area or in a vicinity thereof;
scan-irradiating the process area or the vicinity thereof with the ion beam to etch the process area; and
scan-irradiating a cross-section of the etched process area or vicinity thereof with the electron beam to observe the cross section.
6. A charged particle beam apparatus comprising:
a first charged particle source for generating first charged particles;
a first charged particle optical system for focusing the first charged particles into a first charged particle beam and irradiating an area including an observation point on a surface of a sample with the first charged particle beam under a scanning motion;
a second charged particle source for generating second charged particles;
a second charged particle optical system for focusing the second charged particles into a second charged particle beam and irradiating the area including the observation point on the surface of the sample with the second charged particle beam under a scanning motion;
a secondary electron detector that detects secondary electrons generated by irradiating the sample surface with the first charged particle beam or the second charged particle beam;
display means for displaying a secondary electron image based on the secondary electrons detected by the secondary electron detector;
calculation means for calculating a height of the sample required for focusing the first charged particle beam and the second charged particle beam on the observation point on the surface of the sample;
a sample stage for supporting the sample; and
displacement means for displacing the sample stage to position the sample at the height calculated by the calculation means.
7. A charged particle beam apparatus according to claim 6 ; wherein the calculation means calculates the height of the sample based on magnification of a first secondary electron image obtained by scan-irradiating the observation point on the surface of the sample with the first charged particle beam, magnification of a second secondary electron image obtained by scan-irradiating the observation point on the surface of the sample with the second charged particle beam, and a distance between the observation point in the first secondary electron image and the observation point in the second secondary electron image.
8. A charged particle beam apparatus according to claim 6 ; wherein the first charged particle beam is an electron beam and the second charged particle beam is an ion beam.
9. A sample height regulating method according to claim 1 ; wherein the step of scan-irradiating with the first charged particle beam comprises scan-irradiating with the first charged particle beam using a first charged particle source; and wherein the step of scan-irradiating with the second charged particle beam comprises scan-irradiating with the second charged particle beam using a second charged particle source different from the first charged particle source.
10. A sample height regulating method according to claim 9 ; wherein the first charged particle source is a scanning electron microscope and the second charged particle source is a focused ion beam apparatus.
11. A charged particle beam apparatus according to claim 6 ; wherein the first charged particle source is a scanning electron microscope and the second charged particle source is a focused ion beam apparatus.
12. A charged particle beam apparatus according to claim 11 ; wherein the first charged particle beam is an electron beam and the second charged particle beam is an ion beam.
13. A charged particle beam apparatus according to claim 7 ; wherein the first charged particle beam is an electron beam and the second charged particle beam is an ion beam.
14. A charged particle beam apparatus comprising:
a first charged particle source that generates first charged particles and focuses them into a first charged particle beam that is irradiated on an area including an observation point on a surface of a sample using a scanning motion of the first charged particle beam;
a second charged particle source that generates second charged particles and focuses them into a second charged particle beam that is irradiated on the area of the sample surface including the observation point using a scanning motion of the second charged particle beam;
a secondary electron detector that detects secondary electrons generated when the sample surface is irradiated with the first charged particle beam or the second charged particle beam;
a display that displays a secondary electron image in accordance with the secondary electrons detected by the secondary electron detector;
a calculating device that calculates a height of the sample required for focusing the first charged particle beam and the second charged particle beam on the observation point on the sample surface; and
a displacement device that displaces the sample to position the sample at the height calculated by the calculating device.
15. A charged particle beam apparatus according to claim 14 ; wherein the first charged particle beam is an electron beam and the second charged particle beam is an ion beam.
16. A charged particle beam apparatus according to claim 14 ; wherein the first charged particle source is a scanning electron microscope and the second charged particle source is a focused ion beam apparatus.
17. A charged particle beam apparatus according to claim 16 ; wherein the first charged particle beam is an electron beam and the second charged particle beam is an ion beam.
18. A charged particle beam apparatus according to claim 14 ; wherein the calculation device calculates the height of the sample based on magnification of a first secondary electron image obtained by scan-irradiating the observation point on the surface of the sample with the first charged particle beam, magnification of a second secondary electron image obtained by scan-irradiating the observation point on the surface of the sample with the second charged particle beam, and a distance between the observation point in the magnified first secondary electron image and the observation point in the magnified second secondary electron image.
19. A charged particle beam apparatus according to claim 14 ; further comprising a sample stage that supports the sample; and wherein the displacement device displaces the sample stage to position sample at the height of the sample calculated by the calculating device.
20. A sample height regulating method comprising:
focusing first charged particles into a first charged particle beam and irradiating the first charged particle beam on an area including an observation point on a surface of a sample using a scanning motion of the first charged particle beam;
focusing second charged particles different from the first charged particles into a second charged particle beam and irradiating the second charged particle beam on the area of the sample surface including the observation point using a scanning motion of the second charged particle beam;
detecting secondary electrons generated when the sample surface is irradiated with the first charged particle beam or the second charged particle beam;
calculating a height of the sample required for focusing the first charged particle beam and the second charged particle beam on the observation point on the sample surface; and
positioning the sample at the calculated height.