| 摘要 |
<p>PURPOSE:To detect the accurate position of an alignment mark by a method wherein the height signal of the alignment mark is detected, the transverse- direction positional signal of the alignment mark in a prescribed height position is detected and the position of the mark is found. CONSTITUTION:A signal processing part 13 recognizes a signal detection position as the height of the formation layer of an alignment mark; the optimum position in the Z-axis of a wafer stage 1 is fixed at this point of time by means of a stage control part 14. In succession, the wafer stage 1 starts moving in the transverse direction (the X-direction). The strong intensity of a signal by interference light can be obtained, but only a low-level signal can be detected in the recessed part of the mark. Since the signal processing part 13 recognizes the central position of the end of the alignement mark as the position of the alignment mark, extremely apporoximate positional coordinates can be detected without being affected by the sidewall shape of the alignment mark, by a multilayered thin film and by a photoresist film.</p> |
