| 摘要 |
PURPOSE:To improve workability and to promote uniformity of precision by performing automatically the relative positioning between two objects utilizing diffraction grating. CONSTITUTION:A mask 5 and a wafer 6 are held by a mask holder 2 and a XY table 3 respectively on a supporting mechanism 1 so that the 1st patterns of these correspond to their second patterns, and a laser oscillator 15 is operated to output laser beam L. This laser beam L irradiates the 2nd pattern passing through the 1st pattern after reflected by a reflector 16a. Plus-primary diffracted lights L1-L4 generated by each diffraction grating of the 2nd pattern are received by each light sensors 16-19, and this received light quantity is compared in a signal processing circuit 20. Then, based on this compared value, a driving source 4 is operated to drive a table so that the receiving light quantities of each sensor 16-19 become equal. |
