发明名称 |
Apparatus for detecting a mutual positional relationship of two sample members |
摘要 |
An apparatus for detecting a mutual positional relationship of a semiconductor wafer and mask comprises first and second diffraction gratings formed on the wafer and mask and located parallel to each other; a laser source for radiating a coherent light vertically toward the first and second diffraction gratings; a drive mechanism for periodically varying a relative distance between the first and second diffraction gratings; a pair of photosensors for receiving a first interference beam resulting from those +n-order diffracted beams included in said diffracted beams and a second interference beam resulting from those -n-order diffracted beams included in said diffracted beams; and a differential amplifier calculating the difference between the intensities of the first and second interference lights thereby detecting a mutual positional displacement between the first and second diffraction grating.
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申请公布号 |
US4332473(A) |
申请公布日期 |
1982.06.01 |
申请号 |
US19800114354 |
申请日期 |
1980.01.22 |
申请人 |
TOKYO SHIBAURA DENKI KABUSHIKI KAISHA |
发明人 |
ONO, AKIRA |
分类号 |
G01D5/38;(IPC1-7):G01B9/02 |
主分类号 |
G01D5/38 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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