| 摘要 |
PURPOSE:To enable the detection of surface interval and position slip to be performed with high precision by a method wherein the surface interval between a mask and a wafer is detected by slipping the mutual positions of the mask and the wafer by specific amount corresponding to the dimensions of AA marks. CONSTITUTION:The distance between a spot 30 on the primary focussing surface 32 formed by diffracting the pattern of AA alignment marks (AA marks) 20M1, 20W1 and another spot 31 on the primary focussing surface 32 formed by diffracting the pattern of AA marks 20M2, 20W2 is fluctuated corresponding to the position slip amount between a mask 18 and a wafer 19. On the other hand, the distance between these two spots 30 and 31 is projected on an AA line sensor 12 surface of a photodetector 11 by a photodetecting lens 10. Next, the light intensity of the two spots 30, 31 is detected by the AA line sensor 12 so as to detect the relative position slip between the mask 18 and the wafer 19. Through these procedures, the detection of surface interval and the position slip can be performed with high precision. |
