| 摘要 |
<p>PURPOSE:To perform focusing at an exposing position at every exposure by using exposing light by again forming the images of reflected light from a substrate on a minute pattern array and detecting the intensity of the diffracted light. CONSTITUTION:A pattern array 31 drawn in a pattern section 3 for minute detecting exposure in a scribe area 22 adjacent to a circuit pattern 21 on a reticle 2 is irradiated with light having the same wavelength as that of the light for exposing a fine circuit pattern through a mirror 301. After the principal ray of the illuminating light 30 irradiates the center of the section 3, the zeroth- order transmitted light 301 of the principal ray does not reach a wafer, since the light 301 is blocked on the outside of the entrance pupil 41 of a reduction lens. The first-order diffracted light 300 of the principal ray, on the other hand, passes through the center of the pupil 41 and nearly perpendicularly irradiates the area corresponding to the scribe area 22 of the wafer. The light forming this projection pattern returns the same optical path and is again made incident to the minute pattern array of the section 3 on the reticle after being reflected by the wafer.</p> |
