| 摘要 |
<p>PROBLEM TO BE SOLVED: To prevent dropping of production efficiency and quality degradation in an integrated circuit pattern by stabilizing spectrum width of laser light within one burst period by causing the spectrum width of laser light outputted during an unstable period in one burst period to approach a target spectrum width.SOLUTION: The narrow band laser works by alternately repeating a burst period in which a narrow band laser light is pulse-oscillated continuously and an oscillation pause period in which oscillation is paused. An actuator is controlled in advance, which changes spectrum width by predicting the spectrum width in case pulse oscillation occurs during the oscillation pause period, according to duration of the oscillation pause period. Otherwise, the spectrum width control is performed during unstable period based on actual performance such as a measurement value of spectrum width which is measured during unstable period of spectrum width at previous initial stage of burst or before as well as an operation command value of a spectrum width adjustment mechanism at that time.</p> |
