| 摘要 |
PURPOSE:To perform highly accurate position alignment even if the wavelength of exposing light and the wavelength of aligning light are remarkably different by projecting two direct light beams from two mutually separated region on a first substance to two mutually separated diffracting points on a second substance, and detecting the two obtained diffraction light beams as interference light beams. CONSTITUTION:Aligning light from a laser light source 43 is made to be two light beams through a mirror 44-1 and a prism 44-2. The light beams are projected on mask marks 41-1 and 41-2 of a mask 11, and two n-order diffraction light beams are obtained. At this time, two direct beams (0-order diffraction light beams (d)) are guided to wafer marks 42 of a wafer 12 through a projection lens 13 and inputted into two diffracting points of each wafer mark 42. The light beams are reflected and diffracted, and the two secondary diffracted light beams appear. The two secondary diffraction light beams are inputted into a detector 47-1 as interference light beams. The change in intensities of the interference light beams is detected. Thus, the detected signals having the position deviation data of the wafer 12 are obtained. In this way, the mask 11 and the wafer 12 can be positioned at high accuracy. |
