Patent Number: 
Section: claims

1. A charged particle beam apparatus comprising:a charged particle source;a charged particle optical system for focusing a charged particle beam emitted from said charged particle source and for scanning the focused charged particle beam on a material;a detector for detecting a secondary signal particle which is emitted from said material by being scanned by said charged particle beam; anda control apparatus for detecting an image which is formed by detecting said secondary signal particle, or for detecting periodic information of said material from a line profile, and for measuring an image magnification error based upon the detected periodic information,wherein the control apparatus detects said periodic information by way of an auto-correlation function method in a case that pixel number corresponding to a predetermined portion on said material is larger than a predetermined value, and detects said periodic information by way of a FFT transforming method in a case that pixel number corresponding to a predetermined portion on said material is equal to or smaller than a predetermined value. 2. A charged particle beam apparatus as claimed in claim 1 wherein:said control apparatus measures the image magnification error of said charged particle beam based upon said detected periodic information, and either a pixel size of said image or set image magnification of said image. 3. A charged particle beam apparatus as claimed in claim 2 wherein:said control apparatus calculates an auto-correlation function as to either said image or said line profile so as to calculate said periodic information. 4. A charged particle beam apparatus as claimed in claim 2 wherein:said control apparatus averages said line profile along a predetermined direction, shifts said averaged line profile along a direction different from said predetermined direction so as to calculate an auto-correlation function, and acquires a peak of a correlation value from a distribution of said calculated auto-correlation function. 5. A charged particle beam apparatus as claimed in claim 2 wherein:said control apparatus FFT (Fast Fourier Transformation) transforms said image so as to detect said periodic information. 6. A charged particle beam apparatus as claimed in claim 2 wherein:said control apparatus changes an image magnification control parameter based upon said measured image magnification error. 7. A charged particle beam apparatus as claimed in claim 2 wherein:said control apparatus determines both a total pixel number and image magnification when an image is acquired based upon a material pitch dimension known in the technical field, a selection range for pixel numbers of images, and a selection range of image magnification, and then, said control apparatus acquires an image based upon said determined pixel size and said determined image magnification. 8. A charged particle beam apparatus as claimed in claim 1 wherein:said control apparatus is comprised of:display means for displaying thereon a message in the case that said measured image magnification error exceeds a predetermined range. 9. A charged particle beam apparatus as claimed in claim 1, further comprising:a display apparatus for displaying thereon said measured image magnification error. 10. A charged particle beam apparatus, comprising:a charged particle source;a charged particle optical system for focusing a charged particle beam emitted from said charged particle source and for scanning the focused charged particle beam on a material;a detector for detecting a secondary signal particle which is emitted from said material by being scanned by said charged particle beam; anda control apparatus for detecting an image which is formed by detecting said secondary signal particle, or for detecting periodic information of said material from a line profile, and for measuring an image magnification error based upon the detected periodic information, wherein:said control apparatus detects said periodic information on the basis of a plurality of images obtained in selectively different visual fields in a case that a ratio of a pixel number of a predetermined portion of said material to a pixel number in an image is larger than a predetermined value; andin such a case that a periodic repletion number which is obtained by dividing a total pixel number of said image by a pixel number of said detected periodic information is smaller than a preset value, said control apparatus acquires images in a plurality of different visual fields which have been determined in correspondence with said periodic number, detects a period from each of said acquired plural images, and then, calculates an averaged value from said plurality of the detected periodic information so as to set said averaged value as a representative value of the periods. 11. A charged particle beam apparatus as claimed in claim 10 wherein:said plurality of the different visual fields are obtained by electrically moving (deflecting) an irradiation position of the charged particle beam. 12. A charged particle beam apparatus as claimed in claim 10 wherein:said control apparatus measures the image magnification error of said charged particle beam based upon said detected periodic information, and either a pixel size of said image or set image magnification of said image. 13. A charged particle beam apparatus as claimed in claim 10 wherein:said control apparatus calculates an auto-correlation function as to either said image or said line profile so as to calculate said periodic information. 14. A charged particle beam apparatus as claimed in claim 10 wherein:said control apparatus averages said line profile along a predetermined direction, shifts said averaged line profile along a direction different from said predetermined direction so as to calculate an auto-correlation function, and acquires a peak of a correlation value from a distribution of said calculated auto-correlation function. 15. A charged particle beam apparatus as claimed in claim 10 wherein:said control apparatus FFT (Fast Fourier Transformation)—transforms said image so as to detect said periodic information. 16. A charged particle beam apparatus as claimed in claim 10 wherein:said control apparatus changes an image magnification control parameter based upon said measured image magnification error. 17. A charged particle beam apparatus as claimed in claim 10 wherein:said control apparatus is comprised of:display means for displaying thereon a message in the case that said measured image magnification error exceeds a predetermined range. 18. A charged particle beam apparatus as claimed in claim 10, further comprising:a display apparatus for displaying thereon said measured image magnification error. 19. A charged particle beam apparatus as claimed in claim 10 wherein:said control apparatus determines both a total pixel number and image magnification when an image is acquired based upon a material pitch dimension known in the technical field, a selection range for pixel numbers of images, and a selection range of image magnification, and then, said control apparatus acquires an image based upon said determined pixel size and said determined image magnification.