| 摘要 |
PROBLEM TO BE SOLVED: To improve throughput, while maintaining a satisfactory focusing position. SOLUTION: An aligner or a method of manufacturing a device, wherein an optimal focusing position for making projection exposure of the pattern of an original plate 6 onto a substrate 12, placed on a movable stage 11 via a projection optical system 9, is measured by obtaining predetermined evaluation information which indicates the degree of blurr of an observed image, while observing a reference mark 13 or the surface of the substrate 12 on the stage 11, using a focusing measurement means 27 with the relative position of the plate 6 with respect to the stage 11 changed in the direction of optical axis of the system 9, and projection exposure is performed at this optimal focusing position. In this aligner or method, whether or not an optimal focusing measurement is made is controlled, based on both the evaluation information obtained by the means 27 after a prescribed time has elapsed from the last projection exposure or at a predetermined timing and the evaluation information which is obtained, when the last optimal focusing measurement has been made. |
