Method for optimizing source and mask to control line width roughness and image log slope
First Claim
1. A method for illuminating a mask with a source to project a desired image pattern through a lithographic system onto a photoactive material, the method comprising:
- defining a representation of the mask;
obtaining a fractional resist shot noise (FRSN) parameter;
determining a first relationship between a first set of optical intensity values and an edge roughness metric based on the FRSN parameter;
determining a second relationship between a second set of optical intensity values and a lithographic performance metric;
imposing a set of metric constraints in accordance with one of the first and second relationships;
setting up an objective function of optimization in accordance with the remaining of the first and second relationships;
determining optimum constrained values of the representation of the mask in accordance with the set of metric constraints and the objective function of optimization;
outputting the optimum constrained values of the representation of the mask;
fabricating the mask according to the optimum constrained values of the representation of the mask; and
projecting the mask through the lithographic system onto the photoactive material.
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Abstract
A method for illuminating a mask with a source to project a desired image pattern through a lithographic system onto a photoactive material including: defining a representation of the mask; obtaining a fractional resist shot noise (FRSN) parameter; determining a first relationship between a first set of optical intensity values and an edge roughness metric based on the FRSN parameter; determining a second relationship between a second set of optical intensity values and a lithographic performance metric; imposing a set of metric constraints based on one of the first and second relationships; setting up an objective function of optimization based on the remaining of the two relationships; determining optimum constrained values of the representation of the mask based on the set of metric constraints and the objective function; and outputting these values.
15 Citations
41 Claims
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1. A method for illuminating a mask with a source to project a desired image pattern through a lithographic system onto a photoactive material, the method comprising:
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defining a representation of the mask; obtaining a fractional resist shot noise (FRSN) parameter; determining a first relationship between a first set of optical intensity values and an edge roughness metric based on the FRSN parameter; determining a second relationship between a second set of optical intensity values and a lithographic performance metric; imposing a set of metric constraints in accordance with one of the first and second relationships; setting up an objective function of optimization in accordance with the remaining of the first and second relationships; determining optimum constrained values of the representation of the mask in accordance with the set of metric constraints and the objective function of optimization; outputting the optimum constrained values of the representation of the mask; fabricating the mask according to the optimum constrained values of the representation of the mask; and projecting the mask through the lithographic system onto the photoactive material. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for illuminating a mask with a source to project a desired image pattern through a lithographic system onto a photoactive material, the method comprising:
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defining a representation of the mask; obtaining a fractional resist shot noise (FRSN) parameter; determining a first relationship between a first set of optical intensity values and an edge roughness metric based on the FRSN parameter; determining a second relationship between a second set of optical intensity values and a lithographic performance metric; determining a third relationship between a set of polygons in the mask and a mask-writing difficulty metric; imposing a set of metric constraints in accordance with the first, second, and third relationships; setting up an objective function of optimization in accordance with one of the first, second, and third relationships; determining optimum constrained values of the representation of the mask in accordance with the set of metric constraints and the objective function of optimization; outputting the optimum constrained values of the representation of the mask; fabricating the mask according to the optimum constrained values of the representation of the mask; and projecting the mask through the lithographic system onto the photoactive material.
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10. A method for illuminating a mask with a source to project a desired image pattern through a lithographic system onto a photoactive material, the method comprising:
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defining a representation of the mask and a representation of a projection process; obtaining a fractional resist shot noise (FRSN) parameter; determining a first relationship between a first set of optical intensity values and an edge roughness metric based on the FRSN parameter; determining a second relationship between a second set of optical intensity values and a lithographic performance metric; imposing a set of metric constraints in accordance with one of the first and second relationships; setting up an objective function of optimization in accordance with the remaining of the first and second relationships; determining optimum constrained values of the representations of the mask and the projection process in accordance with the set of metric constraints and the objective function of optimization; outputting the optimum constrained values of the representations of the mask and the projection process; fabricating the mask according to the optimum constrained values of the representation of the mask; and projecting the mask through the lithographic system onto the photoactive material according to the optimum constrained values of the representation of the projection process. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A method for illuminating a mask with a source to project a desired image pattern through a lithographic system onto a photoactive material, the method comprising:
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defining a representation of the mask and a representation of a projection process; obtaining a fractional resist shot noise (FRSN) parameter; determining a first relationship between a first set of optical intensity values and an edge roughness metric based on the FRSN parameter; determining a second relationship between a second set of optical intensity values and a lithographic performance metric; determining a third relationship between a set of polygons in the mask and a mask-writing difficulty metric; imposing a set of metric constraints in accordance with the first, second, and third relationships; setting up an objective function of optimization in accordance with one of the first, second, and third relationships; determining optimum constrained values of the representations of the mask and the projection process in accordance with the set of metric constraints and the objective function of optimization; and outputting the optimum constrained values of the representations of the mask and the projection process; and projecting the mask through the lithographic system onto the photoactive material according to the optimum constrained values of the representation of the projection process.
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21. A machine readable storage medium having one or more machine readable program codes stored thereon for causing the machine to perform a method for illuminating a mask with a source to project a desired image pattern through a lithographic system onto a photoactive material, in the medium, the one or more programs, when executed by a computer, performs the method comprising:
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defining a representation of the mask; obtaining a fractional resist shot noise (FRSN) parameter; determining a first relationship between a first set of optical intensity values and an edge roughness metric based on the FRSN parameter; determining a second relationship between a second set of optical intensity values and a lithographic performance metric; imposing a set of metric constraints in accordance with one of the first and second relationships; setting up an objective function of optimization in accordance with the remaining of the first and second relationships; determining optimum constrained values of the representation of the mask in accordance with the set of metric constraints and the objective function of optimization; and outputting the optimum constrained values of the representation of the mask. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29, 30, 31)
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32. A machine readable storage medium having one or more machine readable program codes stored thereon for causing the machine to perform a method for illuminating a mask with a source to project a desired image pattern through a lithographic system onto a photoactive material, in the medium, the one or more programs, when executed by a computer, performs the method comprising:
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defining a representation of the mask; obtaining a fractional resist shot noise (FRSN) parameter; determining a first relationship between a first set of optical intensity values and an edge roughness metric based on the FRSN parameter; determining a second relationship between a second set of optical intensity values and a lithographic performance metric; determining a third relationship between a set of polygons in the mask and a mask-writing difficulty metric; imposing a set of metric constraints in accordance with the first, second, and third relationships; setting up an objective function of optimization in accordance with one of the first, second, and third relationships; determining optimum constrained values of the representation of the mask in accordance with the set of metric constraints and the objective function of optimization; and outputting the optimum constrained values of the representation of the mask.
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33. A machine readable storage medium having one or more machine readable program codes stored thereon for causing the machine to perform a method for illuminating a mask with a source to project a desired image pattern through a lithographic system onto a photoactive material, in the medium, the one or more programs, when executed by a computer, performs the method comprising:
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defining a representation of the mask and a representation of a projection process; obtaining a fractional resist shot noise (FRSN) parameter; determining a first relationship between a first set of optical intensity values and an edge roughness metric based on the FRSN parameter; determining a second relationship between a second set of optical intensity values and a lithographic performance metric; imposing a set of metric constraints in accordance with one of the first and second relationships; setting up an objective function of optimization in accordance with the remaining of the first and second relationships; determining optimum constrained values of the representations of the mask and the projection process in accordance with the set of metric constraints and the objective function of optimization; and outputting the optimum constrained values of the representations of the mask and the projection process. - View Dependent Claims (34, 35, 36, 37, 38, 39, 40)
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41. A machine readable storage medium having one or more machine readable program codes stored thereon for causing the machine to perform a method for illuminating a mask with a source to project a desired image pattern through a lithographic system onto a photoactive material, in the medium, the one or more programs, when executed by a computer, performs the method comprising:
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defining a representation of the mask and a representation of a projection process; obtaining a fractional resist shot noise (FRSN) parameter; determining a first relationship between a first set of optical intensity values and an edge roughness metric based on the FRSN parameter; determining a second relationship between a second set of optical intensity values and a lithographic performance metric; determining a third relationship between a set of polygons in the mask and a mask-writing difficulty metric; imposing a set of metric constraints in accordance with the first, second, and third relationships; setting up an objective function of optimization in accordance with one of the first, second, and third relationships; determining optimum constrained values of the representations of the mask and the projection process in accordance with the set of metric constraints and the objective function of optimization; and outputting the optimum constrained values of the representations of the mask and the projection process.
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Specification