| 摘要 |
<P>PROBLEM TO BE SOLVED: To reduce adverse effects on resist pattern formation due to speckle noise, by allowing laser beams to have low space coherence. <P>SOLUTION: Beams from an oscillation-stage laser (MO) 10 are injected into a resonator of an amplification stage laser (PO) 20 via an MO beam-steering unit 30, and are amplified and oscillated. Beams from the amplification stage laser (PO) 20 are inciden on an OPS 50 via a PO beam steering unit 40, and light from the OPS 50 is outputted via a coherence monitor 60. A laser coherence controller 66 sends a drive signal to the actuator of the mirror of the MO beam steering unit 30 that of the PO beam steering unit 40, or the like, based on the detection value of the coherence motor 60 to control the angles, or the like, of the mirrors so that the coherence of output laser beams reaches a desired value. <P>COPYRIGHT: (C)2009,JPO&INPIT |
