| 摘要 |
PURPOSE:To enable to accurately catch the respective residual oscillation of the X and the Y axes after the time when transfer of the exposing position on the X and the Y stages ended by a method wherein the respective oscillation is simultaneously sampled at high speed on the X and Y axes and the oscillation amplitudes of the X and the Y axes are respectively measured on the basis of data obtained from the sampling. CONSTITUTION:Discrete position information, which are sent from a stage position instrumentation unit at a time point when a comparison timing 14 has generated, are simultaneously sampled by a sampling signal 18 at high speed on an X axis 16 and a Y axis 17, and the sampled information are respectively held in an X register 19 and a Y register 20. The computer compares the held data with data in the maximum and the minimum registers housing in the computer. By repeating the comparison operation at a period less than one-tenth of the respective oscillation period, calculation of the maximum values and the minimum values of oscillation within a section before the decision timing generates is executed. By this method, the oscillation amplitudes of the X and the Y axes within the section are found out and whether the amplitudes have been respectively converged within its prescribed extent is decided. As a result, the respective residual oscillation of the X and the Y axes after the time when transfer of the exposing positon on the X and the Y stages ended can be accurately catched. |
