| 摘要 |
<p>A method and a device for controlling a narrow-band oscillation excimer laser used as a source of light for a reduced-scale projection exposure device. The laser oscillator contains at least two wavelength select elements. There are carried out the center wavelength control for bringing the oscillation center wavelength determined by these wavelength select elements into agreement with a desired wavelength, the superpose control for superposing the wavelengths that have transmitted through these wavelength select elements, and the power control that controls the laser output by controlling a voltage applied to the electrodes in the laser chamber. The gas is replaced partly as a voltage applied to the electrodes in the laser chamber is increased. After the gas is partly replaced, the control period is set to be nearly the same for the superpose control and for the power control, or the superpose control is inhibited while the power control is being carried out. When the laser is energized, the superpose control is executed first, and then the center wavelength control is executed.</p> |
