| 摘要 |
PURPOSE:To constantly assure the positions of the first element by a method wherein the first reference to be the alignment index of the first element such as a reticle as well as the second reference to be the alignment index of the second element such as a wafer at specified relative position to the first refer ence are monitored. CONSTITUTION:A mercury 1 is used for a light source. A g-beam is selected from the beams emitted from the mercury lamp 1 to lead the beam into a main body through the intermediary of an optical fiber 3. The fiber 3 is fixed to enter the beam into an optical system irradiating a main body side reticle alignment mark (main body side RA mark) upward. The main body side RA mark and (reticle side RA mark existing at specified gap are transmission- irradiated with this beam to image-form respective RA marks on a CCD or an image-pick up tube 9. Any detected image is fed to a computer (image proces sor) 13 to be image-processed for detecting relative slips of respective RA marks. Through these procedures, the data are transmitted to a reticle stage driving system to correct the slip for making alignment of the reticle with the main body. |
