| 摘要 |
<p>PURPOSE:To save a space and to reduce the cost, by a method wherein an optical system and a photodetector are made to be shared by an alignment system of a scanning beam system and an alignment system of a static beam system. CONSTITUTION:After passing through beam expanders 11, 12 and a cylindrical lens 12a, a laser beam from a laser light source 10 is reflected by a scanner mirror 13 and converged as a slit-shaped spot light SP on a pattern surface of a reticle R through relay lenses 14, 15, a mirror 16, an objective lens 17 and a mirror 18. A movable mirror body 20 is provided in an optical path so that it can be moved forward and backward by a switching drive system 21, and the beam is stopped or scanned with the forward or backward motion thereof. Optical information from a mark of the reticle R or a mark of a wafer W is returned to a beam splitter 30 and it is reflected thereon and detected by a photoelectric element 32.</p> |
