| 摘要 |
PROBLEM TO BE SOLVED: To stably perform automatic-focusing by improving non-linear characteristics caused by a ringing phenomenon in an automatic focusing optical system. SOLUTION: The automatic focusing apparatus in an optical measuring apparatus including an illumination optical system and an observation optical system 10, is provided with a wedge mirror 23 arranged in almost a pupil position in an automatic focusing optical path, an AF photoelectric conversion element 26 for obtaining an image nearly conjugate to a position detection mark M on a wafer W in response to the reflected light transmitted through the wedge mirror, a focusing position detecting apparatus 31 for calculating a focusing error signal based on an image imaged by the element 26, and a wafer stage 33 for adjusting the position of the wafer in the optical axis direction based on the focusing error signal, and a relay lens 22 arranged in the automatic focusing optical path is shifted in a direction shown by an arrow A so as to shift the focal position of the image by a prescribed amount. COPYRIGHT: (C)2006,JPO&NCIPI |
