Back to results
US 5,469,260 AGranted
Stage-position measuring apparatus
AssigneeNikon Corporation
InventorsShinichi Takagi, Kenji Nishi
Life of this patent
Estimating the term…
Abstract
An apparatus for measuring the position of a movable stage by the use of a laser interferometer is of a construction in which covers are provided on respective ones of a beam optical path for reference travelling toward a fixed mirror in the laser interferometer and a beam optical path for measurement travelling toward a movable mirror and temperature-controlled gas is supplied into the covers.
Claims7
A position measuring apparatus for detecting a position of a stage movable in a predetermined direction on a base, comprising:
- a movable mirror having a reflecting surface perpendicular to the direction of movement of said stage and mounted on a portion of said stage;
- a fixed mirror disposed fixedly relative to said base;
- a light wave interferometer projecting coherent light beams substantially perpendicularly to respective ones of said movable mirror and said fixed mirror, causing the light beams reflected by respective ones of said movable mirror and said fixed mirror to interfere with each other and receiving said light beams, and photoelectrically detecting said interference beams and outputting a measurement signal;
- a position detecting circuit for detecting the position of said stage based on said measurement signal;
- first cover means covering a beam optical path from said light wave interferometer to said fixed mirror;
- second cover means covering a beam optical path from said light wave interferometer to said movable mirror, said second cover means having its dimension in the direction of said beam optical path variable with the movement of said stage;
- and
- gas supply means for supplying gas of controlled temperature to interiors of said first cover means and said second cover means at a predetermined flow rate.
5 more elements
A position measuring apparatus for detecting a position of a stage movable in a predetermined direction on a base, comprising:
- a movable mirror having a reflecting surface perpendicular to the direction of movement of said stage and mounted on a portion of said stage;
- a fixed mirror disposed fixedly relative to said base;
- a light wave interferometer projecting coherent light beams substantially perpendicularly to respective ones of said movable mirror and said fixed mirror, causing the light beams reflected by respective ones of said movable mirror and said fixed mirror to interfere with each other and receiving the reflected light beams, and photoelectrically detecting said interference beams and outputting a measurement signal;
- a position detecting circuit for detecting the position of said stage based on said measurement signal;
- cover means covering a beam optical path from said light wave interferometer to said fixed mirror, said cover means being invariable in its dimension in the direction of said beam optical path;
- and
- gas supply means for supplying gas of controlled temperature to an interior of said cover means at a predetermined flow rate.
4 more elements
A position measuring apparatus for detecting a position of a stage movable in a predetermined direction on a base, comprising:
- a movable mirror having a reflecting surface perpendicular to the direction of movement of said stage and mounted on a portion of said stage;
- a fixed mirror disposed fixedly relative to said base;
- a light wave interferometer projecting coherent light beams substantially perpendicularly to respective ones of said movable mirror and said fixed mirror, causing the light beams reflected by respective ones of said movable mirror and said fixed mirror to interfere with each other and receiving the reflected light beams, and photoelectrically detecting the interference beams and outputting a measurement signal;
- a position detecting circuit for detecting the position of said stage based on said measurement signal;
- first cover means covering a beam optical path from said light wave interferometer to said fixed mirror;
- second cover means covering a part of a beam optical path from said light wave interferometer to said movable mirror which is near said movable mirror;
- and
- gas supply means for supplying gas of controlled temperature to interiors of said first cover means and said second cover means at a predetermined flow rate, and flowing said gas of controlled temperature within said second cover means from said movable mirror toward said light wave interferometer.
5 more elements
Dependencies are inferred from the claim text.