POSITION DETECTING APPARATUS BY DOUBLE LINEAR FRESNEL ZONE PLATE THROUGH ILLUMINATION WITH MULTI WAVELENGTHS

摘要

PURPOSE:To achieve high throughput by providing a cylindrical lens between an objective lens and a linear sensor, processing signals obtained from said linear sensor and detecting the position of an alignment mark. CONSTITUTION:A wafer 15 and a mask 14 are overlapped with each other by a gap 18 of several tens mum. In the right and left upwards in a slantwise direction from the wafer 15 and mask 14, there are provided an illuminating optical device 5 and a detecting optical device 10 confronting each other. An illuminating angle 19 of incident light from an optical axis of the device 5 for a normal line of the mask 14 or wafer 15 is selected to be equal to a slantwise detecting angle 20 of an optical axis of the device 10. The illuminating light and detecting light are thus inclined for the mask 14 and wafer 15. Therefore, alignment marks 16, 17 within an X-ray exposing region 13 can be detected without moving the devices 5, 10. Furthermore, because the device 10 is placed outside an optical path of the region 13, the marks 16, 17 can be detected even during the exposing time, and it is not necessary to move the device 10 at every alignment; thereby, high throughput can be achieved.