| 摘要 |
PURPOSE:To improve the through-put in detection of positioning marks by a method wherein, when an overlapped or approached condition is generated on one of the image signal waveform patterns of each positioning mark, the pattern having wider width is detected, the relative position of a wafer and a mask is recognized without performing a step-feeding process, thereby enabling to cut down the time required for alignment. CONSTITUTION:When an overlapped or approached condition is generated on one of image signal waveform patterns of each positioning mark, it is considered that the overalpped or approached condition is generated on the wafer concerned and the positiong mark of the mask by detecting the pattern having wider width, and the relative positional relation is matched by calcurating the amount of positional deviation between the two. For example, pattern widths D1=Iu1-d1I and D2=Iu2-d2I are calculated by an arithmetic operation circuit 15 using the edge informations d1 and d2 of the positioning mark image signal waveform pattern on the mark and the edge information u1 and u<2> making a pair with the above- mentioned informations, and it is recognized that the positioning mark is approached to the wafer 2 having wider width between pattern widths D1 and D2, or that the positioning mark is overlapped. |
