To provide a lithographic apparatus with an autofocus system.
The lithographic apparatus comprises a lighting system which supplies a radiation beam, a pattern grant equipment which gives a pattern to the cross-section of the radiation beam and forms a patterned radiation beam, a substrate table configured to hold a substrate, and a projection system that includes a plurality of mirrors arranged to project the patterned radiation beam onto a target portion of the substrate. The lithographic apparatus further includes the autofocus system having (a) a light source, (b) a position sensitive detector, and (c) a light directing arrangement. The light directing arrangement directs a first portion of light from the light source to the projection system, and directs a second portion of light from the light source into the position sensitive detector. After the first portion of light has traveled through the projection system to the substrate and back through the projection system to the light directing arrangement, the first portion of light is directed to the position sensitive detector.
VAN DIJSSELDONK ANTONIUS JOHAN
| JPH09115822A | 1997-05-02 | |||
| JP2002164276A | 2002-06-07 | |||
| JPH09283423A | 1997-10-31 |
Hajime Asamura
Katsunori Shirae
Yutaka Yoshida