PROCESS TUNING WITH POLARIZATION
First Claim
1. A method for configuring an illumination source of a lithographic apparatus to enhance the imaging of a mask pattern onto a substrate, the image of the mask pattern on the substrate having a plurality of critical dimensions, the method comprising:
- dividing the illumination source into pixel groups, each pixel group including one or more illumination source points in a pupil plane of the illumination source;
changing a polarization state of each pixel group and determining an incremental effect on each of the plurality of critical dimensions resulting from the change of polarization state of each pixel group;
calculating a first plurality of sensitivity coefficients for each of the plurality of critical dimensions using the determined incremental effects;
selecting an initial illumination source;
iteratively calculating a lithographic metric as a result of a change of polarization state of a pixel group in the initial illumination source using the calculated first plurality of sensitivity coefficients, the change of the polarization state of the pixel group in the initial illumination source creating a modified illumination source; and
adjusting the initial illumination source based on the iterative results of calculations.
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Accused Products
Abstract
A method for configuring an illumination source of a lithographic apparatus, the method including dividing the illumination source into pixel groups, each pixel group including one or more illumination source points in a pupil plane of the illumination source; changing a polarization state of each pixel group and determining an incremental effect on each of the plurality of critical dimensions resulting from the change of polarization state; calculating a first plurality of sensitivity coefficients for each of the plurality of critical dimensions using the determined incremental effects; selecting an initial illumination source; iteratively calculating a lithographic metric as a result of a change of polarization state using the calculated first plurality of sensitivity coefficients, the change of the polarization state of the pixel group in the initial illumination source creating a modified illumination source; and adjusting the initial illumination source based on the iterative results of calculations.
18 Citations
20 Claims
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1. A method for configuring an illumination source of a lithographic apparatus to enhance the imaging of a mask pattern onto a substrate, the image of the mask pattern on the substrate having a plurality of critical dimensions, the method comprising:
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dividing the illumination source into pixel groups, each pixel group including one or more illumination source points in a pupil plane of the illumination source; changing a polarization state of each pixel group and determining an incremental effect on each of the plurality of critical dimensions resulting from the change of polarization state of each pixel group; calculating a first plurality of sensitivity coefficients for each of the plurality of critical dimensions using the determined incremental effects; selecting an initial illumination source; iteratively calculating a lithographic metric as a result of a change of polarization state of a pixel group in the initial illumination source using the calculated first plurality of sensitivity coefficients, the change of the polarization state of the pixel group in the initial illumination source creating a modified illumination source; and adjusting the initial illumination source based on the iterative results of calculations. - View Dependent Claims (2, 3, 4)
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5. A computer product having machine executable instructions, the instructions being executable by a machine to perform a method for configuring an illumination source of a lithographic apparatus to enhance the imaging of a mask pattern onto a substrate, the image of the mask pattern onto the substrate having a plurality of critical dimensions, the method comprising:
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dividing the illumination source into pixel groups, each pixel group including one or more illumination source points in a pupil plane of the illumination source; changing a polarization state of each pixel group and determining an incremental effect on each of the plurality of critical dimensions resulting from the change of polarization state of each pixel group; calculating a first plurality of sensitivity coefficients for each of the plurality of critical dimensions using the determined incremental effects; selecting an initial illumination source; iteratively calculating a lithographic metric as a result of a change of polarization state of a pixel group in the initial illumination source using the calculated first plurality of sensitivity coefficients, the change of the polarization state of the pixel group in the initial illumination source creating a modified illumination source; and adjusting the initial illumination source based on the iterative results of calculations.
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6. A lithographic apparatus comprising:
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an illumination source configured to condition a beam of radiation; a substrate table configured to hold a substrate; a projection system configured to project a beam of radiation patterned by a patterning device onto a surface of the substrate; and a processor configured to perform a method for configuring the illumination source to enhance the imaging of a pattern onto a substrate, the image of the mask pattern onto the substrate having a plurality of critical dimensions, the method comprising; dividing the illumination source into pixel groups, each pixel group including one or more illumination source points in a pupil plane of the illumination source; changing a polarization state of each pixel group and determining an incremental effect on each of the plurality of critical dimensions resulting from the change of polarization state of each pixel group; calculating a first plurality of sensitivity coefficients for each of the plurality of critical dimensions using the determined incremental effects; selecting an initial illumination source; iteratively calculating a lithographic metric as a result of a change of polarization state of a pixel group in the initial illumination source using the calculated first plurality of sensitivity coefficients, the change of the polarization state of the pixel group in the initial illumination source creating a modified illumination source; and adjusting the initial illumination source based on the iterative results of calculations.
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7. A method for configuring an illumination source of a lithographic apparatus to enhance the imaging of a mask pattern, the method comprising:
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dividing a pupil plane of the illumination source into pixel groups, each pixel group including one or more illumination source pixels in the pupil plane; selecting an initial set of pixel groups of the illumination source as an initial illumination source; iteratively changing a polarization state of a pixel group from at least a subgroup of the set of selected pixel groups in the initial illumination source, calculating a lithographic metric associated with at least a part of the mask pattern as a result of the changed polarization state, and applying the change of the polarization state of the pixel group to generate a modified illumination source when the calculated lithographic metric is improved due to the changed polarization state; and adjusting the initial set of pixel groups of the illumination source based on the iterative results of calculations. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14, 15)
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16. A method for configuring an illumination source of a lithographic apparatus to enhance the imaging of a mask pattern, the method comprising:
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performing a source mask optimization procedure using scalar imaging to provide a preliminary optimized illumination source and a preliminary optimized mask pattern, and performing a source mask polarization optimization procedure using, as initial conditions, the preliminary optimized illumination source and the preliminary optimized mask pattern.
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17. A method for configuring a transfer of an image of a pattern onto a substrate in a lithographic apparatus, said pattern to be illuminated by an illumination source of the lithographic apparatus, the method comprising:
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determining a first illumination source configured to illuminate said pattern; performing a source mask polarization optimization procedure that takes into account three dimensional effects associated with said pattern, said source mask polarization optimization procedure performed using said first illumination source as an initial illumination source in said source mask polarization optimization procedure. - View Dependent Claims (18, 19, 20)
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Specification