Patent Number: 
Section: claims

1. A charged particle beam application device comprising:a specimen stage on which a specimen is mounted;an irradiation optical system to scan said specimen mounted on said specimen stage with a primary charged particle beam;a detector to detect secondary charged particles generated by the scanning with said charged particle beam; anda display means to display the output signals from said detector in the form of images,wherein said irradiation optical system comprises:an aberration corrector to correct the aberration of said incoming primary charged particle beam; anda means for dividing an optical path of either said primary charged particle beam entering said aberration corrector or said primary charged particle beam having passed through said aberration corrector into plural optical paths. 2. A charged particle beam application device according to claim 1, wherein said means for dividing the optical path of said primary charged particle beam into plural optical paths is a stop having plural openings. 3. A charged particle beam application device according to claim 1,wherein said stop has a first aperture group having plural openings through which said primary charged particle beam divided into said plural optical paths passes, andwherein said first aperture group has a first opening, and plural second openings disposed symetrically around a center axis of said first opening. 4. A charged particle beam application device according to claim 3, wherein said irradiation optical system has a high-voltage wobbler function. 5. A charged particle beam application device according to claim 3, wherein said plural second openings include at least two openings disposed at the positions twofold rotationally symmetrical around the center of said first opening. 6. A charged particle beam application device according to claim 3, wherein said plural second openings include at least two openings disposed at the positions either fourfold rotationally symmetrical or eightfold rotationally symmetrical around the center of said first opening. 7. A charged particle beam application device according to claim 3, wherein said stop has a third opening disposed in addition to said first aperture group. 8. A charged particle beam application device according to claim 7, including a stop moving means of retracting either said first aperture group or said third opening from the optical axis of said primary charged particle beam. 9. A charged particle beam application device according to claim 8, including a control means for controlling said stop moving means,wherein said display means is connected to said control means, andwherein an icon to select any of said first aperture group, said second aperture group, and said third opening is displayed on said display means. 10. A charged particle beam application device according to claim 8, including:a control means for controlling said stop moving means; andan input means for selecting any of said first aperture group, said second aperture group, and said third opening. 11. A charged particle beam application device comprising:a specimen stage on which a specimen is mounted;an irradiation optical system to scan said specimen mounted on said specimen stage with a primary charged particle beam;a detector to detect secondary charged particles generated by the scanning with said charged particle beam; anda display means to display the output signals from said detector in the form of images,wherein said irradiation optical system comprises:a charged particle beam source;an aberration corrector to correct the aberration of said incoming primary charged particle beam; anda stop disposed between said charged particle beam source and said aberration corrector, andwherein said stop has a first opening disposed on an optical axis of the primary charged particles emitted from said charged particle beam source, and plural second openings disposed symmetrically around a center axis of said first opening. 12. A charged particle beam application device according to claim 11, wherein said charged particle beam source is an electron source. 13. A wafer inspection device using a charged particle beam application device according to any one of the claims 1 to 8 and 9 to 12, said wafer inspection device comprising a means for judging existence or nonexistence of defect in said specimen on the basis of the output signals of said detector. 14. A critical-dimension-measurement device using a charged particle beam application device according to any one of the claims 1 to 8 and 9 to 12, said critical-dimension-measurement device comprising a means for measuring the dimension of a pattern formed on said specimen on the basis of the output signals of said detector. 15. A charged particle beam application device comprising:a specimen stage on which a specimen is mounted;an irradiation optical system to scan said specimen mounted on said specimen stage with a primary charged particle beam;a detector to detect secondary charged particles generated by the scanning with said primary charged particle beam; anda display means to display the output signals from said detector in the form of images,wherein said irradiation optical system comprises:an aberration corrector to correct the aberration of said incoming primary charged particle beam; anda first stop for dividing an optical path of either said primary charged particle beam entering said aberration corrector or said primary charged particle beam having passed through said aberration corrector into plural optical paths. 16. A charged particle beam application device according to claim 15 further comprising a second stop having an orbicular zone aperture and a shield from the primary charged particle beam arranged in the center of the orbicular zone. 17. A charged particle beam application device according to claim 16, further comprising a means for switching said first stop and said second stop. 18. A charged particle beam application device according to claim 16, wherein the orbicular zone aperture comprises a plurality of round apertures. 19. A wafer inspection device using a charged particle beam application device according to any one of the claims 15 and 16 to 18, said wafer inspection device comprising a means for judging existence or nonexistence of defect in said specimen on the basis of the output signals of said detector. 20. A critical-dimension-measurement device using a charged particle beam application device according to any one of the claims 15 and 16 to 18, said critical-dimension-measurement device comprising a means for measuring the dimension of a pattern formed on said specimen on the basis of the output signals of said detector.