Magnetically-positioned X-Y stage having six-degrees of freedom
First Claim
1. An apparatus for magnetically positioning a movable X-Y stage with respect to X and Y horizontal axes and a Z vertical axis that comprises:
- a first set of a plurality of flat stationary electromagnetic coils of wire that substantially lie in a first horizontal X, Y plane and are angularly offset in said first horizontal X, Y plane by plus an oblique angle with respect to a given one of said X and Y horizontal axes;
a second set of a plurality of flat stationary electromagnetic coils of wire that substantially lie in a second horizontal X, Y plane substantially in vertical alignment with said first horizontal X, Y plane and are angularly offset in said second horizontal X, Y plane by minus said oblique angle with respect to the same one of said X and Y horizontal axes as said first set of coils of wire; and
a Halbach array of magnets attached to said movable X-Y stage, wherein said array substantially lies in a third horizontal X, Y plane, is oriented substantially parallel to the same one of said X and Y horizontal axes with respect to which said oblique angles are measured, and is simultaneously situated in a cooperative relationship with both of said first and second sets of coils of wire;
whereby a lateral force in said X and/or Y horizontal directions and/or a vertical force in said vertical Z direction may be selectively generated in accordance with the phase and magnitude of current energizing a wire of some of each of said plurality of flat stationary electromagnetic coils of said first and second sets.
2 Assignments
0 Petitions
Accused Products
Abstract
The respective square cross-section permanent magnets of each of a plurality of spaced Halbach magnet arrays, attached to the bottom of movable X-Y stage and aligned with a given one of the X and Y axes, are spaced from one another parallel to the other one of the X and Y axes of by the width of the square cross-section cooperates with both a first set of a plurality of flat stationary electromagnet coils of wire and a second set of a plurality of flat stationary electromagnet coils of wire that substantially lie in proximate horizontal X, Y planes and, respectively, are angularly offset by +45° and -45° with respect to the given one of the X and Y horizontal axes to provide a lateral translational force on the stage with respect to the horizontal X and/or Y axes and/or a levitating translational force on the stage with respect to the vertical Z axis. First, second and third pairs of spaced electromagnets attached to the bottom of movable X-Y stage and situated in spaces between adjacent Halbach magnet arrays cooperate with both the first and second sets electromagnet coils of wire to create couples that can tilt the stage about the X and/or Y axes and/or yaw the stage about the Z axis. This configuration of Halbach magnet arrays and electromagnetic coils provides a compact and energy efficient X-Y stage suitable for use in a wafer-stepper for positioning a large (e.g., 200-300 mm.) silicon wafer employed in the photolithographic manufacture of monolithic integrated circuits.
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Citations
19 Claims
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1. An apparatus for magnetically positioning a movable X-Y stage with respect to X and Y horizontal axes and a Z vertical axis that comprises:
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a first set of a plurality of flat stationary electromagnetic coils of wire that substantially lie in a first horizontal X, Y plane and are angularly offset in said first horizontal X, Y plane by plus an oblique angle with respect to a given one of said X and Y horizontal axes; a second set of a plurality of flat stationary electromagnetic coils of wire that substantially lie in a second horizontal X, Y plane substantially in vertical alignment with said first horizontal X, Y plane and are angularly offset in said second horizontal X, Y plane by minus said oblique angle with respect to the same one of said X and Y horizontal axes as said first set of coils of wire; and a Halbach array of magnets attached to said movable X-Y stage, wherein said array substantially lies in a third horizontal X, Y plane, is oriented substantially parallel to the same one of said X and Y horizontal axes with respect to which said oblique angles are measured, and is simultaneously situated in a cooperative relationship with both of said first and second sets of coils of wire; whereby a lateral force in said X and/or Y horizontal directions and/or a vertical force in said vertical Z direction may be selectively generated in accordance with the phase and magnitude of current energizing a wire of some of each of said plurality of flat stationary electromagnetic coils of said first and second sets. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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Specification