Dynamic fluid control system for immersion lithography
First Claim
1. An apparatus, comprising:
- a stage that supports a substrate;
an optical system that projects an image onto the substrate, the optical system having a last optical element that is spaced from the substrate by a gap at least partly filled with an immersion liquid; and
a dynamic force control system that maintains a substantially constant force on the last optical element and the stage by locally changing the immersion liquid pressure in the gap to compensate for dynamic changes of the immersion liquid caused by motion of the immersion liquid through the gap and/or movement of the stage.
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Accused Products
Abstract
A dynamic fluid control system and method capable of reducing dynamic forces from the fluid on the last optical element (20) and substrate stage (14) caused by the motion of the immersion fluid. The system includes an imaging element (12) that defines an image and a stage (14) configured to support a substrate (16). An optical system (18) is provided to project the image defined by the imaging element onto the substrate. The optical system (18) includes a last optical element (20). A gap (22) filled with immersion fluid is provided between the substrate (16) and the last optical element (20). A dynamic force control system (34) is provided to maintain a substantially constant force on the last optical element and the stage (14) by compensating for dynamic changes of the immersion fluid caused by the motion of the immersion fluid through the gap and/or movement of the stage.
27 Citations
29 Claims
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1. An apparatus, comprising:
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a stage that supports a substrate; an optical system that projects an image onto the substrate, the optical system having a last optical element that is spaced from the substrate by a gap at least partly filled with an immersion liquid; and a dynamic force control system that maintains a substantially constant force on the last optical element and the stage by locally changing the immersion liquid pressure in the gap to compensate for dynamic changes of the immersion liquid caused by motion of the immersion liquid through the gap and/or movement of the stage. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29)
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Specification