发明名称 |
Apparatus for measuring position of an X-Y stage |
摘要 |
An interferometer used to measure distance to an object is provided with a laser sheath. The sheath encloses a substantial part of the measurement beam's path to provide a controlled environment which reduces environmental influences on the measured distance. The sheath is of variable length and responsive to a follower so as to maintain a sheath end nearest the object at a small distance from the object. An environmental controller controls the environment within the sheath. The environment within the sheath can be a vacuum or a suitable gas or gas mixture. A corrector can be used to compensate the interferometer's measured-distance signal for detected environmental characteristics to produce a corrected signal which indicates distance between the interferometer and the reflective surface. The apparatus and methods can be used to measure and control stage position in a projection-type wafer exposure system which is affected by variations in its atmospheric environment.
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申请公布号 |
US5552888(A) |
申请公布日期 |
1996.09.03 |
申请号 |
US19940349733 |
申请日期 |
1994.12.02 |
申请人 |
NIKON PRECISION, INC. |
发明人 |
SOGARD, MICHAEL R.;LEE, MARTIN E. |
分类号 |
G01B11/00;G01B9/02;G03F7/20;G03F9/00;H01L21/027;(IPC1-7):G01B9/02 |
主分类号 |
G01B11/00 |
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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