ERRONEOUS TRANSCRIPTION ADJUSTING DEVICE

摘要

PURPOSE:To adjust the optical system minimizing erroneous transcription by a method wherein the mutual matching status of alignment is detected. CONSTITUTION:The laser beam l transmitted from a laser beam source 10 is scanned by a polygon mirror 12 advancing to a reference mask 16 etc. through a half mirror 14. The alignment mark 1 of the reference mask 16 and the alignment mark 2 of the reference wafer 18 are scanned by the laser beam l through the intermediary of the transcription on optical system 17 returning to the half mirror 14 again where both said marks 1 and 2 are overlapped as shown in the drawing a partly reflected in the direction of photoelectric conversion element 20. The laser beam l scans in the scanning direction A from left to right while the photoelectric conversion element 20 detects the pulse type output at the position where said laser beam l intersects with said alignment marks 1 and 2. Any mismatching may be detected by means of measuring the time intervals W1,W2...W5 between pulse signals.