| 摘要 |
PROBLEM TO BE SOLVED: To suppress the occurrence of TISs (errors caused by equipment). SOLUTION: An overlay inspection device is provided with a stage 11 on which a wafer 10 is placed, an illumination stop 13, condenser lenses 14 and 15, a half mirror 16, a lighting optical system which leads the light from a light source 12 to the wafer 10 through an objective lens 17, an image picking-up optical system which fetches the image of the wafer 10 to a CCD sensor 18 through the lens 17 and mirror 16, and a picture processing section 19 which processes picture signals outputted from the sensor 18. The overlay inspection device uses a two-luminous-flux lighting system which forms an image on the wafer 10 by using two luminous fluxes of zeroth- and first-order light as the lighting optical system and and a four-opening type stop as the illumination step 13. |
