| 摘要 |
<p>PURPOSE:To accurately recognize an alignment mark at a high speed even if it is near circuit patterns by forming said mark in the aggregate of microsegments having approximately 45 deg. inclination with respect to an ordinary pattern configuration direction, and making coherent luminous flux into striplike focused light. CONSTITUTION:An alignment mark 1 consists of the aggregate of microsegments having a direction of approximately 45 deg. with respect to the orthogonal (x) axis direction of circuit patterns. Since the diffracted beams 5, 6 of light from the mark 1 exit and arrive at regions 3, 4 in a longitudinal direction, photoelectric converting detectors are provided in these regions. A spot 2 and a wafer scan relatively, but in the case of the figure, they scan in the (y) axis direction, and at the time when the spot 2 falls onto the mark 1, the outputs of the photoelectric converting detectors go maximum.</p> |
