| 摘要 |
PURPOSE:To make it possible to perform highly accurate position alignment when a first body and a second body are relatively positioned by constituting one physical optic element of two physical optic elements with a linear grating lens, and utilizing the signal light beams. CONSTITUTION:First and second physical optic elements 3 and 4 having optical property are formed on a first body 1 such as a mask for position alignment and on the surface of a second body such as a wafer, respectively. One physical optic element 4 of the two elements is constituted with a linear grating lens element. Diffracted light beams 6 and 7 are set so that the diffracted light beams 6 and 7 on a specified plane have the reverse signs with respect to the amount of deviation between the light beams by using two detecting systems having the different orders. Even if the surface of the wafer is inclined or the positions of the centers of gravity of the alignment light beams 6 and 7 are changed by local inclination and the like, the relative positions of the centers of gravity of the two alignment signal light beams are detected. In this way, the position deviation can be accurately detected regardless of the inclination of the wafer surface. |
