Position measuring system for use in lithographic apparatus
US6894261B2 · kind B2 · utility
6Cited by
23References
23Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Dec 20, 2000 |
| Grant date | May 17, 2005 |
| Priority date | — |
| Expiry date | Dec 20, 2020 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F9/7049
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A position measuring apparatus includes a radiation source mounted on an isolated reference frame and a two-dimensional radiation detector mounted adjacent the radiation source. The object whose position is to be detected has a retro-reflector mounted on it so as to reflect light emitted from the radiation source along a return path that is parallel to but displaced from the incident light path. The amount of displacement is dependent on the position of the object and is measured by the two-dimensional detector. Three such apparatus can be combined in a system to measure the position of the object in all six degrees of freedom.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.