| 摘要 |
<p>PURPOSE:To make corrections following the change of environmental conditions by a method wherein an X-Y stage aligning light axis moving apparatus is so controlled as to make a reference pattern detection value conform to a 1st reference by a focus adjusting and controlling means. CONSTITUTION:A reference pattern is lit by a lighting source provided in a pattern detection optical system 9 and its image is projected and focused onto the original picture of a reticle 11 through a contraction lens 10. The reference pattern image and a reticle window pattern are enlarged together by the optical system 9 and re-forcused on a photosensor 13. The output signal of the sensor 13 is digitized by an A/D converter 14 and introduced to a computer system 15. The reticle 11 can be moved along the Z-direction by a mechanism 16 and a motor 17. The moved distance is detected by an encoder 18. With this constitution, correction following the change of environmental conditions can be made.</p> |
