Lithographic apparatus, device manufacturing method
AssigneeASML Netherlands B.V.
InventorsJohannes Catharinus Hubertus Mulkens, Wilhelmus Petrus De Boeij, Carsten Andreas Kohler
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Abstract
To compensate for birefringence of a mask in a lithographic projection apparatus, the birefringence of a mask is measured and stored as birefringence data in a data storage device. A birefringent compensation element is disposed in the optical path of the lithographic projection apparatus. Appropriate adjustments of the compensation element are determined as those optimally reducing impact of the mask birefringence on the state of polarization at substrate level.
Claims24
A lithographic apparatus arranged to project a pattern from a patterning device onto a substrate using an electro-magnetic radiation beam, comprising:
- a data storage device arranged to receive and store data characterizing a birefringence property of the patterning device,
- a manipulator comprising one or more birefringent elements disposed in a path traversed by the radiation beam and arranged to adjust said one or more birefringent elements to change a polarization state of the radiation beam, and
- a controller responsive to said data and arranged to control adjusting by the manipulator to compensate impact of the patterning device on a polarization state of said radiation beam at substrate level.
A device manufacturing method comprising projecting a pattern from a patterning device onto a substrate using an electro-magnetic radiation beam, the method comprising:
- storing data characterizing a birefringence property of the patterning device,
- adjusting one or more birefringent elements to change a polarization state of said radiation beam, and
- controlling said adjusting to compensate impact of the patterning device on a polarization state of said radiation beam at substrate level.
Dependencies are inferred from the claim text.