| 摘要 |
PURPOSE:To realize a method for detecting position at a high speed with high accuracy by providing slit window pattern on a reticle pattern, and setting an illumination optical system for detecting patterns through a half mirror between the reticle and a reduced projection lens. CONSTITUTION:When the pattern 50 on a wafer 5 is illuminated by the light emitted from an illumination optical system for detection consisting of a light source 9, an illumination lens system 10, an aperture 11 and a half mirror 12, the reflected projection image is formed through a projection lens 4 on the slit window pattern 30 on a reticle 20. If a DC servocontrol motor 18 is driven to move the wafer 5 in an arrow direction with a feed screw 19, the distribution in the quantity of light in the scanning direction of the reflected projection image is detected with a photodetector 15 by the pattern 30. The moving position of the wafer 5 is detected with laser interferometers 7, 8, and the signal thereof 21 is fed to a control circuit 16, so that the signal 22 for the change in the quantity of light corresponding to the position is taken into the circuit 16. The position where the pattern 30 faces the wafer 5 is detected at a high speed with high accuracy by a control device 17 including a computer. |
