| 摘要 |
PROBLEM TO BE SOLVED: To improve the tracking performance of the energy control device of an excimer laser with respect to alterations of the objective value of pulse energy in a pulse oscillation in a burst operation mode and to control each pulse energy to be constant. SOLUTION: An energy control device is constituted in such a structure, that when pulse oscillation takes place in a burst operation mode, continuous pulse oscillations and continuous pulse oscillation interrupt during a prescribed time are repeated alternately, a learning control is executed in the initial stage of each continuous pulse oscillation. After the learning control, the control of each pulse is executed and at the learning control, the current voltage command voltage Vi is calculated, on the basis of the result of the first pulse oscillation at the time of the last continuous pulse oscillation at the first pulse oscillation from the start of the oscillation and at the time of the control of above each pulse, the current voltage command value VI is calculated on the basis of the result of the oscillation immediately prior to the same time's continuous pulse oscillation to provide an output control part 10, to make the pulse oscillations take place and each pulse energy is controlled. In this case, the control part 10 corrects the voltage command values Vi and VI corresponding to the amount of the change in the objective value Ed of each pulse energy at the time of the learning control and at the control of each pulse. For example, a voltage correction valueΔV for responding to a difference between both voltage command values, which respectively correspond to the current objective value Ed and a reference value, is added to the voltage command values Vi and VI for correcting the command values Vi and VI. |
