| 摘要 |
PURPOSE:To contrive to shorten effectively the scanning distance and to shorten scanning time of an electron beam by a method wherein only the extremely nearby part of the edge part of a mark is scanned by the electron beam. CONSTITUTION:Aiming at effective shortening of the scanning distance of the beam, a means to scan only the neighborhood (the solid line parts of loci 8) of the edge parts 7 of the mark to constitute the most important informations to detect the pattern of the mark is provided. Because scanning of the beam is performed by generating a beam scanning signal through a D/A converter, interlaced scanning can be performed easily by changing digital signals to be applied to the D/A converter. By this method, beam scanning of two places for about 5mum at the neighborhood of the mark is enough for one scanning, beam scanning time is shortened to 1/6 of the customary method, and even when the other treating time is made to be contained, the time required can be shortened to 1/2 on the whole as compared with the customary method. |
