POSITION DETECTOR AND MANUFACTURE OF DEVICE USING IT

摘要

PROBLEM TO BE SOLVED: To accurately detect the relative position displacement between objects by allowing a diffracted light generating from a light entering an optical element on one object to enter an optical element on the other object and detecting an positional information on a given surface of the generated diffracted light. SOLUTION: Alignment marks 10 and 11 consisting of physical optical elements are formed on the surface of a mask (first object) 8 and alignment marks 12 and 13 comprising physical optical elements are formed on the surface of a wafer (second object) 9. The physical optical elements 10 to 12 are formed of diffraction grid. A light flux emitted from a light source 1 is made parallel through a collimator lens 2 and deflected through a mirror 5, and then it enters the physical elements 10 and 11 on a mask 8 inside an exposure area 7. The light flux affected optically by the elements 10 and 11 enters the physical optical elements 12 and 13 on the wafer 9. The diffracted lights from the respective physical optical elements include an information on the horizontal displacement quantity between the mask 8 and wafer 9, to form image on the light reception surface of a photodetector 15.