| 摘要 |
PURPOSE:To perform automatic positioning in a direction of rotation, by providing perpendicular cross signs of different width in two regions in the direction of the axis X of a substrate coordinate system parallel with a facet and by effecting scanning with an electron beam. CONSTITUTION:Perpendicularly intersecting lines L, M are made different in width from each other so that a firstly scanned line can be discriminated in terms of the distance between the peaks of a signal of reflected electrons in beam scanning 22 or 23. As a result, it can be judged whether the intersecting points P11, P12 of an axis X for a substrate, which extends on the intersecting points of the lines L, M, with the normals on the middle points between the intersecting points of the lines L, M with a scanning line are located above or below the scanning line. Errors in the substrate coordinates axis 21 and a beam coordinates axis 22 or 23 and the positiveness or negativeness of the errors can be detected by conventional calculation on the basis of the coordinates of the intersecting points P11, P12. The length of beam scanning with these X-shaped L, M can be reduced to about a half of that of beam scanning with V-shaped lines to heighten the accuracy of positioning. According to this method, sign regions are reduced, an error in a direction of rotation can be detected for an area of similar size and the accuracy of error correction is enhanced. |
