| 摘要 |
PURPOSE:To conform the position of the focus of a reducing glass for a stepper and height set by a height measuring mechanism easily by fitting a photoelectric conversion element receiving beams transmitting a pattern for a reticle onto a stage, covering the phtoelectric conversion element with a light-shielding plate and forming a through- hole to the light-shielding plate in an exposure device. CONSTITUTION:When beams are projected from the upper section of a reticle 1, a pattern 1a for the reticle 1 reduce by a reading glass 2 is projected onto a light- shielding plate 3. The bright section of the projected pattern is shown by a region 7 and a dark section a shaded section region 8, and the intensity of light is represented by E. When the focus is adjusted at that time, the intensity of light of brightness and darkness suddenly changes as shown in 9: when the focus is not adjusted, the intensity of light gently changes as shown in 10. The intensity of light forms a triangular wave when the light-shielding plate 3 is positioned at the position of the focus of the glass, and the crest and trough sections of the triangular wave are rounded gradually when the plate 3 is displaced from the position of the focus. The position of the focus of the reducing glass is defined by the changes of the crest and trough sections of the triangular wave, and a height measuring mechanism can be set at the height.
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