| 摘要 |
PROBLEM TO BE SOLVED: To correct straightness errors of movable mirrors without driving a wafer stage. SOLUTION: Prior to exposure, a laser beam is applied from laser interferometers 7a, 7b to a movable mirror 11a for measuring a position of a wafer stage 5 in an X direction, the wafer stage 5 is step-by-step moved in a Y direction and then the straightness error of the movable mirror 11a for ever step is calculated from measured values of the laser interferometers 7a, 7b. Thereby a straightness map of straightness errors with respect to the position of the wafer stage 5 for the movable mirror 11a is made and stored in a memory 9. Likewise, a straightness map for a movable mirror 11b in the Y direction is made. During exposure, positional errors and yawing of the wafer stage 5 in the X and Y directions based on the straightness errors of the movable mirrors 11a, 11b are corrected by driving a reticle stage 4 in X, Y and rotational directions based on the straightness maps stored in the memory 9. |
