Source-mask optimization in lithographic apparatus
First Claim
1. A method for optimizing an illumination source of a lithographic apparatus and a mask, the method comprising:
- dividing the illumination source into a plurality of pixel groups, each pixel group including one or more illumination source points;
dividing the mask into a plurality of mask tiles;
selecting an initial illumination shape for the illumination source;
selecting an initial mask pattern for the mask;
selecting an initial configuration for at least one lithographic process component;
selecting a lithographic model for a photolithographic simulation;
ranking pixel groups in the plurality of pixel groups and mask tiles in the plurality of mask tiles;
for each pixel group in the plurality of pixel groups and each mask tile in the plurality of mask tiles, in order of ranking, performing the steps of;
calculating, based on a result of the photolithographic simulation using the lithographic model, a lithographic metric as a result of an alteration in state of the each pixel group or the each mask tile;
based on a result of the calculation, adjusting an illumination shape of the illumination source by altering a state of the each pixel group to create a modified illumination shape or adjusting a mask pattern of the mask by altering a state of the each mask tile to create a modified mask pattern.
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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; selecting an illumination shape to expose a pattern, the illumination shape formed with at least one pixel group; ranking the pixel groups according to how a change in state of a pixel group affects a lithographic metric; and for each pixel group in order of ranking, determining whether to adjust the illumination shape by changing the state of the pixel group based on a calculation of the lithographic metric as a result of a change in state of the pixel group.
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Citations
20 Claims
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1. A method for optimizing an illumination source of a lithographic apparatus and a mask, the method comprising:
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dividing the illumination source into a plurality of pixel groups, each pixel group including one or more illumination source points; dividing the mask into a plurality of mask tiles; selecting an initial illumination shape for the illumination source; selecting an initial mask pattern for the mask; selecting an initial configuration for at least one lithographic process component; selecting a lithographic model for a photolithographic simulation; ranking pixel groups in the plurality of pixel groups and mask tiles in the plurality of mask tiles; for each pixel group in the plurality of pixel groups and each mask tile in the plurality of mask tiles, in order of ranking, performing the steps of; calculating, based on a result of the photolithographic simulation using the lithographic model, a lithographic metric as a result of an alteration in state of the each pixel group or the each mask tile; based on a result of the calculation, adjusting an illumination shape of the illumination source by altering a state of the each pixel group to create a modified illumination shape or adjusting a mask pattern of the mask by altering a state of the each mask tile to create a modified mask pattern. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A non-transitory computer program product having machine executable instructions, the instructions being executable by a machine to perform a method for optimizing an illumination source of a lithographic apparatus and a mask, the method comprising:
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dividing the illumination source into a plurality of pixel groups, each pixel group including one or more illumination source points; dividing the mask into a plurality of mask tiles; selecting an initial illumination shape for the illumination source; selecting an initial mask pattern for the mask; selecting an initial configuration for at least one lithographic process component; selecting a lithographic model for a photolithographic simulation; ranking pixel groups in the plurality of pixel groups and mask tiles in the plurality of mask tiles; for each pixel group in the plurality of pixel groups and each mask tile in the plurality of mask tiles, in order of ranking, performing the steps of; calculating, based on a result of the photolithographic simulation using the lithographic model, a lithographic metric as a result of an alteration in state of the each pixel group or the each mask tile; based on a result of the calculation, adjusting an illumination shape of the illumination source by altering a state of the each pixel group to create a modified illumination shape or adjusting a mask pattern of the mask by altering a state of the each mask tile to create a modified mask pattern.
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18. A lithographic apparatus comprising:
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an illumination system configured to condition a beam of radiation; a substrate table configured to hold a substrate; a projection system configured to project the beam of radiation patterned by a patterning device onto a surface of the substrate; and a processor to perform a method for optimizing an illumination source of the lithographic apparatus and a mask, the method comprising; dividing the illumination source into a plurality of pixel groups, each pixel group including one or more illumination source points; dividing the mask into a plurality of mask tiles; selecting an initial illumination shape for the illumination source; selecting an initial mask pattern for the mask; selecting an initial configuration for at least one lithographic process component; selecting a lithographic model for a photolithographic simulation; ranking pixel groups in the plurality of pixel groups and mask tiles in the plurality of mask tiles; for each pixel group in the plurality of pixel groups and each mask tile in the plurality of mask tiles, in order of ranking, performing the steps of; calculating, based on a result of the photolithographic simulation using the lithographic model, a lithographic metric as a result of an alteration in state of the each pixel group or the each mask tile; based on a result of the calculation, adjusting an illumination shape of the illumination source by altering a state of the each pixel group to create a modified illumination shape or adjusting a mask pattern of the mask by altering a state of the each mask tile to create a modified mask pattern.
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19. A method for configuring an illumination source of a lithographic apparatus, the method comprising:
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determining, for each pixel group in a plurality of pixel groups, a linear sensitivity value that indicates how an alteration in state of the each pixel group from an initial state affects a lithographic response; until the lithographic response converges, repeating the steps of; for each pixel group in the plurality of pixel groups, calculate the lithographic response based on the linear sensitivity value of the each pixel group; altering a state of a particular pixel group to an updated state, the calculated lithographic response for the particular pixel group indicating a greater amount of improvement over a current lithographic response than a calculated lithographic responses for pixel groups other than the particular pixel group, the current lithographic response calculated based on current states of the pixel groups; and updating the current lithographic response based on the updated state of the particular pixel group. - View Dependent Claims (20)
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Specification