Multiple electron beam inspection apparatus and multiple electron beam inspection method
According to one aspect of the present invention, a multiple electron beam inspection apparatus includes a reference image generation circuit generating reference images corresponding to the secondary electron images, in accordance with an image generation characteristic of a secondary electron image by irradiation of one beam; and a correction circuit generating corrected reference images in which, on the basis of deviation information between a figure pattern of the secondary electron image by irradiation of the one beam of the multiple primary electron beams and a figure pattern of a secondary electron image by irradiation of another beam different from the one beam of the multiple primary electron beams, a shape of a figure pattern of a reference image corresponding to the figure pattern of the secondary electron image by the irradiation of the another beam in the reference images is corrected.
1. A multiple electron beam inspection apparatus comprising:
a secondary electron image acquisition mechanism acquiring secondary electron images of figure patterns by irradiating a substrate formed with the figure patterns with multiple primary electron beams and detecting multiple secondary electron beams emitted from the substrate in accordance with the irradiation of the multiple primary electron beams;
a reference image generation circuit generating reference images corresponding to the secondary electron images, in accordance with an image generation characteristic of a secondary electron image by irradiating one beam of the multiple primary electron beams, based on design data of the figure patterns;
a correction circuit generating corrected reference images in which, on the basis of deviation information between a figure pattern of the secondary electron image by irradiating the one beam of the multiple primary electron beams and a figure pattern of a secondary electron image by irradiating another beam different from the one beam of the multiple primary electron beams, a shape of a figure pattern of a reference image corresponding to the figure pattern of the secondary electron image by the irradiation of the another beam in the reference images is corrected; and
a comparison circuit comparing a secondary electron image of the secondary electron images and a corrected reference image of the corrected reference images.
2. The multiple electron beam inspection apparatus according to claim 1 , wherein the correction circuit corrects an edge shape of the figure pattern of the reference image corresponding to the figure pattern of the secondary electron image by the irradiation of the another beam in the reference images, by comparing peak intensities and trail amounts of edge slopes between the figure pattern of the secondary electron image by irradiation of the one beam of the multiple primary electron beams and the figure pattern of the secondary electron image by irradiation of the another beam different from the one beam of the multiple primary electron beams.
3. The multiple electron beam inspection apparatus according to claim 1 , wherein deviation information of inclinations of edge slope between the figure pattern of the secondary electron image by irradiation of the one beam and the figure pattern of the secondary electron image by irradiation of the another beam is obtained by comparing the secondary electron images of the calibration patterns by irradiating a calibration substrate formed with the calibration patterns with the multiple primary electron beams and detecting multiple secondary electron beams emitted from the calibration substrate in accordance with irradiation of the multiple primary electron beams.
4. The multiple electron beam inspection apparatus according to claim 1 , wherein deviation information of inclinations of edge slope between the figure pattern of the secondary electron image by irradiation of the one beam and the figure pattern of the secondary electron image by irradiation of the another beam is acquired by the secondary electron images of the figure patterns of the substrate to be inspected.
5. The multiple electron beam inspection apparatus according to claim 1 , wherein the correction circuit generates the corrected reference images in which an edge shape of a figure pattern of a reference image corresponding to the figure pattern of the secondary electron image by irradiation of the one beam in the reference images is not corrected and an edge shape of a figure pattern of a reference image corresponding to the figure pattern of the secondary electron image by irradiation of the another beam in the reference images is corrected.
6. The multiple electron beam inspection apparatus according to claim 5 , wherein a center beam of the multiple primary electron beams is used as for the one beam.
7. The multiple electron beam inspection apparatus according to claim 1 , further comprising:
a filter function calculation circuit calculating a coefficient of a filter function to generate the reference image according to the image generation characteristic of the secondary electron image by irradiation of the one beam, by a secondary electron image acquired in a sample region of an inspection region of the substrate and a design image of the sample region based on the design data.
8. The multiple electron beam inspection apparatus according to claim 7 , wherein the filter function calculation circuit calculates the coefficient of the filter function by an image portion by irradiation of the one beam in the secondary electron image of the sample region.
9. The multiple electron beam inspection apparatus according to claim 7 , wherein both a region where a figure pattern having a narrow line width is disposed and a region where a figure pattern having a wide line width is disposed are set as the sample region.
10. A multiple electron beam inspection method comprising:
acquiring secondary electron images of figure patterns by irradiating a substrate formed with the figure patterns with multiple primary electron beams and detecting multiple secondary electron beams emitted from the substrate in accordance with the irradiation of the multiple primary electron beams;
generating reference images corresponding to the secondary electron images, in accordance with an image generation characteristic of a secondary electron image by irradiating one beam of the multiple primary electron beams, based on design data of the figure patterns;
generating corrected reference images in which, on the basis of deviation information between a figure pattern of the secondary electron image by irradiating the one beam of the multiple primary electron beams and a figure pattern of a secondary electron image by irradiating another beam different from the one beam of the multiple primary electron beams, a shape of a figure pattern of a reference image corresponding to the figure pattern of the secondary electron image by the irradiation of the another beam in the reference images is corrected; and
comparing a secondary electron image of the secondary electron images and a corrected reference image of the corrected reference images and outputting a comparison result.
11. The multiple electron beam inspection method according to claim 10 , wherein an edge shape of the figure pattern of the reference image corresponding to the figure pattern of the secondary electron image by the irradiation of the another beam in the reference images is corrected by peak intensities and trail amounts of edge slopes between the figure pattern of the secondary electron image by irradiation of the one beam of the multiple primary electron beams and the figure pattern of the secondary electron image by irradiation of the another beam different from the one beam of the multiple primary electron beams.
12. The multiple electron beam inspection method according to claim 10 , wherein deviation information of inclinations of edge slope between the figure pattern of the secondary electron image by irradiation of the one beam and the figure pattern of the secondary electron image by irradiation of the another beam is acquired by the secondary electron images of the figure patterns of the substrate to be inspected.
13. The multiple electron beam inspection method according to claim 10 , wherein the corrected reference images in which an edge shape of a figure pattern of a reference image corresponding to the figure pattern of the secondary by irradiation of the one beam in the reference images is not corrected and an edge shape of a figure pattern of a reference image corresponding to the figure pattern of the secondary electron image by irradiation of the another beam in the reference images is corrected are generated.
14. The multiple electron beam inspection method according to claim 10 , further comprising:
calculating a coefficient of a filter function to generate the reference image according to the image generation characteristic of the secondary electron image by irradiation of the one beam, by a secondary electron image acquired in a sample region of an inspection region of the substrate and a design image of the sample region based on the design data.
15. The multiple electron beam inspection method according to claim 14 , wherein the coefficient of the filter function is calculated by an image portion by irradiation of the one beam in the secondary electron image of the sample region.