Method and system for lithography process-window-maximizing optical proximity correction
First Claim
1. A method comprising:
- computing, using a computer hardware system, an analytical function of a process condition parameter that approximates an aerial or resist image value across a process window for each of a plurality of evaluation points in a target pattern for a lithographic process;
determining a target value of the image value for each evaluation point based on the analytical function and a nominal condition comprising a nominal value of the process condition parameter, wherein determining the target value for each evaluation point is performed such that the process window about the nominal value of the process condition parameter is increased or maximized; and
performing, by the computer hardware system, optical proximity correction on the target pattern, using the target value as an optimizing target for each evaluation point, for physically manufacturing a physical patterning device based on the target pattern or for physically performing the lithographic process on a substrate based on the target pattern.
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Abstract
An efficient OPC method of increasing imaging performance of a lithographic process utilized to image a target design having a plurality of features. The method includes determining a function for generating a simulated image, where the function accounts for process variations associated with the lithographic process; and optimizing target gray level for each evaluation point in each OPC iteration based on this function. In one given embodiment, the function is approximated as a polynomial function of focus and exposure, R(ε,ƒ)=P0+ƒ2·Pb with a threshold of T+Vε for contours, where PO represents image intensity at nominal focus, ƒ represents the defocus value relative to the nominal focus, ε represents the exposure change, V represents the scaling of exposure change, and parameter “Pb” represents second order derivative images. In another given embodiment, the analytical optimal gray level is given for best focus with the assumption that the probability distribution of focus and exposure variation is Gaussian.
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Citations
20 Claims
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1. A method comprising:
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computing, using a computer hardware system, an analytical function of a process condition parameter that approximates an aerial or resist image value across a process window for each of a plurality of evaluation points in a target pattern for a lithographic process; determining a target value of the image value for each evaluation point based on the analytical function and a nominal condition comprising a nominal value of the process condition parameter, wherein determining the target value for each evaluation point is performed such that the process window about the nominal value of the process condition parameter is increased or maximized; and performing, by the computer hardware system, optical proximity correction on the target pattern, using the target value as an optimizing target for each evaluation point, for physically manufacturing a physical patterning device based on the target pattern or for physically performing the lithographic process on a substrate based on the target pattern. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method comprising:
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forming an analytical function of a process condition parameter of a lithographic process to approximate a value of an aerial or resist image characteristic; approximating values of the image characteristic across a plurality of values of the process condition parameter for each of a plurality of evaluation points in a target pattern using the analytical function; determining, using a computer hardware system, a target value of the image characteristic for each evaluation point based on the approximated values of the image characteristic corresponding to a maximum range of values of the process condition parameter; and performing, by the computer hardware system, optical proximity correction on the target pattern, using the target value as an optimizing target for each evaluation point, for physically manufacturing a physical patterning device based on the target pattern or for physically performing the lithographic process on a substrate based on the target pattern. - View Dependent Claims (8, 9, 10, 11)
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12. A non-transitory computer-readable storage medium having computer-executable instructions stored therein to cause a computer to at least:
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compute an analytical function of a process condition parameter that approximates an aerial or resist image value across a process window for each of a plurality of evaluation points in a target pattern; determine a target value of the image value for each evaluation point based on the analytical function and a nominal condition comprising a nominal value of the process condition parameter, wherein determining the target value for each evaluation point is performed such that the process window about the nominal value of the process condition parameter is increased or maximized; and perform optical proximity correction on the target pattern, using the target value as an optimizing target for each evaluation point, for physically manufacturing a physical patterning device based on the target pattern or for physically performing the lithographic process on a substrate based on the target pattern. - View Dependent Claims (13, 14, 15, 16, 17)
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18. A non-transitory computer-readable storage medium having computer-executable instructions stored therein to cause a computer to at least:
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form an analytical function of a process condition parameter of a lithographic process to approximate a value of an aerial or resist image characteristic; approximate values of the image characteristic across a plurality of values of the process condition parameter for each of a plurality of evaluation points in a target pattern using the analytical function; determine a target value of the image characteristic for each evaluation point based on the approximated values of the image characteristic corresponding to a maximum range of values of the process condition parameter; and perform optical proximity correction on the target pattern, using the target value as an optimizing target for each evaluation point, for physically manufacturing a physical patterning device based on the target pattern or for physically performing the lithographic process on a substrate based on the target pattern. - View Dependent Claims (19, 20)
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Specification