| 摘要 |
PURPOSE:To highly accurately measure the focusing position of a projecting optical system at a high speed and to calibrate inclination detecting systems in a short time. CONSTITUTION:Reference patterns 28A-28D are irradiated with irradiating light which is emitted from the lower surface of a pattern plate 8 and has the same wavelength as exposing light IL has. A photoelectric detector 14 receives a luminous flux returned from the pattern surface of a reticle R through a projecting optical system 6 and the patterns 28A-28D after the luminous flux is projected upon the pattern surface through the optical system 6 and reflected by the pattern surface. A signal processing unit 16 detects the focusing position of the optical system 6 based on a detecting signal S1 outputted from the detector 14 when the plate 8 and image forming surface of the optical system 6 are relatively moved in the direction of the optical axis. A main control system 27 finds the optimum image forming surface from focusing position at a plurality of positions in the image field of the optical system 6 and calibrates inclination detecting systems 17 and 18 by using the plate 8 in a state where the optimum image forming surface is made coincident with the surface of the plate 8. |
