| 摘要 |
<p>PURPOSE:To improve the accuracy in detection of an alignment position by automatically changing a reference signal in order, according to the preset rule, and setting the reference signal so that the correlatively operated value may be maximum. CONSTITUTION:The signal D[x] issued from a mark for positioning is detected. At this time, in case that the intensity of a signal is not within a certain determined range, the intensity is adjusted. Next, the position where the maximum value of a correlation value AO(x) can be obtained is detected by performing the correlation operation between it and a reference signal SO(x). Furthermore, it is so arranged that the position can be detected between it and a further suitable reference signal S1(x) by enabling the reference signal SO(x) to be automatically changed, according to the signal. An alignment position can be detected with high accuracy by seeking such a reference signal that the maximum value of the correlation value can be gotten, this way.</p> |
