Method For Forming Arbitrary Lithographic Wavefronts Using Standard Mask Technology
First Claim
1. A method for generating a desired set of diffracted waves using features of a lithographic mask for which a set of supported transmissions are chosen from a set of supported values, by the steps of:
- creating at a computer a representation of the mask as a set of polygonal elements,defining constraints for the computer which require that the ratio of spatial frequencies in the representation take on amplitude ratios of the desired set of diffracted waves, andusing an optimization algorithm stored in a memory of the computer to adjust transmission discontinuities at edges of the polygonal elements to substantial equality with discontinuity values allowed by the set of supported transmissions while maintaining the constraints.
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Accused Products
Abstract
A desired set of diffracted waves using mask features whose transmissions are chosen from a set of supported values are generated. A representation of the mask as a set of polygonal elements is created. Constraints which require that the ratio of the spatial frequencies in the representation take on the amplitude ratios of the desired set of diffracted waves are defined. An optimization algorithm is used to adjust the transmission discontinuities at the edges of the polygons to substantial equality with the discontinuity values allowed by the set of supported transmissions while maintaining the constraints.
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Citations
14 Claims
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1. A method for generating a desired set of diffracted waves using features of a lithographic mask for which a set of supported transmissions are chosen from a set of supported values, by the steps of:
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creating at a computer a representation of the mask as a set of polygonal elements, defining constraints for the computer which require that the ratio of spatial frequencies in the representation take on amplitude ratios of the desired set of diffracted waves, and using an optimization algorithm stored in a memory of the computer to adjust transmission discontinuities at edges of the polygonal elements to substantial equality with discontinuity values allowed by the set of supported transmissions while maintaining the constraints. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A memory storing a program of computer readable instructions executable by a processor to perform actions directed to generating a desired set of diffracted waves using features of a lithographic mask for which a set of supported transmissions are chosen from a set of supported values, the actions comprising:
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creating a representation of the mask as a set of polygonal elements, defining constraints which require that the ratio of the spatial frequencies in the representation take on the amplitude ratios of the desired set of diffracted waves, and using an optimization algorithm to adjust transmission discontinuities at edges of the polygonal elements to substantial equality with the discontinuity values allowed by the set of supported transmissions while maintaining the constraints. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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Specification