| 摘要 |
PROBLEM TO BE SOLVED: To rapidly and accurately judge front or rear surface of a substrate. SOLUTION: Sub-orientations OF1, OF2 for judging front or rear surface are formed except an orientation flat OF formed heretofore on a wafer W in a linear profile. A method for measuring the position includes first imaging the outer edge of the wafer W by using pre-alignment sensors 22a, 22b, and 22c disposed at a preset positional relationship, then extracting point group having a plurality of points along the profile of the wafer W from the imaged result of the pre-alignment sensor 22c, and linearly approximating the extracted point group by a least square method. The method also includes obtaining the positional relationship of the point group to the obtained approximate straight line, and judging whether a circular arc edge CE is disposed as a curved profile directly under the pre-alignment sensor 22c or not or sub-orientation OF1 is disposed or not to judge the front or rear surface of the wafer W. COPYRIGHT: (C)2005,JPO&NCIPI
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