| 摘要 |
PURPOSE:To enable highly-precise position alignment of a mask with a projecting lens and with a wafer by forming two first diffraction gratings on a first substance and a second diffraction grating on a second substance. CONSTITUTION:A high-reflection mirror 16 and a half mirror 17 are disposed above a mask 11, and a minus primary diffracted light q1 generated at a first mark 14 is led to a photoelectric detector 18 by the high-reflection mirror 16 through the half mirror 17. A plus primary diffracted light p1 generated at a first mark 13 is led to the photoelectric detector 18 by the half mirror 17. The minus primary diffracted light q1 and the plus primary diffracted light p1 interfere with each other at the half mirror 17 and an interference light e1 is sent to the detector 18. Then, a detection signal of the detector 18 is sent to a signal processing circuit 19. Besides, a high-reflection mirror 20 is provided above a second mark 15, a reflected interference light e2 generated at the second mark 15 is led to a photoelectric detector 21 and a detection signal is sent to a signal processing circuit 22. By this constitution, the mask can be aligned in position with a projecting lens and also with a wafer. |
