Patent US5394520A successfully refreshed from Google Patents.
EP0302178A2
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Position sensor
Assignee: Sumitomo Heavy Industries Ltd
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Filing: 1988-04-11
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Granted: —
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Expires: 2008-04-11
Abstract
Abstract An apparatus senses the positions of two objects separated from each other by a very small distance on the order of several microns to several tens of microns, such as the distance between a mask and a wafer in an X-ray exposure system. The apparatus is provided with a lens system for imaging the marks of the two objects in an identical plane by visible light having two different wavelengths, and a filter for cancelling blurring caused by chromatic aberration. The images of the respective marks are optically processed. Thus, the positional relationship of the two objects can be sensed by a single lens and the small distance between the objects can be accurately set.
Inventors
- 👤 Tsutomu Miyatake
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-02 02:05
CPC Classifications
G; G03; G03F; G03F9/00; G03F9/70; G03F9/7003; G03F9/7023; G03F9/7026
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
131 words
An apparatus for sensing the positions of first and second objects separated from each other by a very small distance, comprising: a lens system designed in accordance with the distance between the first and second objects and visible light having first and second suitably set wavelengths for imaging, in an identical plane, a mark of the first object by the visible light of the first wavelength and a mark of the second object by the visible light of the second wavelength; a filter for cancelling light other than the light for imaging, said filter conforming to the shapes of the respective imaged marks of the first and second objects; and a processing system for processing images passed by said filter and indicating a positional relationship between the first and second objects.
Claim 2
Independent Claim
131 words
An apparatus for sensing the positions of first and second objects separated from each other by a very small distance, comprising: a lens system designed in accordance with the distance between the first and second objects and visible light having first and second suitably set wavelengths for imaging, in an identical plane, a mark of the first object by the visible light of the first wavelength and a mark of the second object by the visible light of the second wavelength; a filter for cancelling light other than the light for imaging, said filter conforming to the shapes of the respective imaged marks of the first and second objects; and a processing system for processing images passed by said filter and indicating a positional relationship between the first and second objects.
Claim 3
Dependent Claim
37 words
The apparatus according to Claim 1, wherein said filter comprises: a first coated surface for passing only the light of the first wavelength; and a second coated surface for passing only the light of the second wavelength.
Claim 4
Independent Claim
130 words
An apparatus for sensing the positions of first and second objects separated from each other by a very small distance, comprising: a lens system designed in accordance with the distance between the first and second objects and visible light having first and second suitably set wavelengths for imaging, in an identical plane, a mark of the first object by the visible light of the first wavelength and a mark of the second object by the visible light of the second wavelength; a filter for cancelling light other than the light for imaging, said filter conforming to positions of the respective iamged marks of the first and second objects; and a processing system for processing images passed by said filter and indicating a positional relationship between the first and second objects.
Claim 5
Independent Claim
130 words
An apparatus for sensing the positions of first and second objects separated from each other by a very small distance, comprising: a lens system designed in accordance with the distance between the first and second objects and visible light having first and second suitably set wavelengths for imaging, in an identical plane, a mark of the first object by the visible light of the first wavelength and a mark of the second object by the visible light of the second wavelength; a filter for cancelling light other than the light for imaging, said filter conforming to positions of the respective iamged marks of the first and second objects; and a processing system for processing images passed by said filter and indicating a positional relationship between the first and second objects.
Claim 6
Dependent Claim
37 words
The apparatus according to Claim 3, wherein said filter comprises: a first coated surface for passing only the light of the first wavelength; and a second coated surface for passing only the light of the second wavelength.
References Cited (Backward Citations)
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