Lithography verification using guard bands
First Claim
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1. A computer-implemented method for verifying a lithographic process, comprising:
- defining a set of guard bands around a target pattern, wherein the target pattern is to be printed on a semiconductor die using a photo-mask in the lithographic process;
using a processor to calculate an estimated pattern using a model of the lithographic process, wherein the model of the lithographic process includes a mask pattern corresponding to the photo-mask and a model of an optical path, wherein an inverse optical calculation was used to determine the mask pattern at an object plane in the optical path based at least in part on the target pattern at an image plane in the optical path and the model of the optical path, and wherein the model of the optical path includes information in addition to a magnification of the optical path; and
determining if positions of differences between the estimated pattern and the target pattern exceeded one or more guard bands in the set of guard bands.
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Abstract
A method for verifying a lithographic process is described. During the method, a set of guard bands are defined around a target pattern that is to be printed on a semiconductor die using a photo-mask in the lithographic process. An estimated pattern is calculated using a model of the lithographic process. This model of the lithographic process includes a mask pattern corresponding to the photo-mask and a model of an optical path. Then, whether or not positions of differences between the estimated pattern and the target pattern exceeded one or more guard bands in the set of guard bands is determined.
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Citations
22 Claims
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1. A computer-implemented method for verifying a lithographic process, comprising:
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defining a set of guard bands around a target pattern, wherein the target pattern is to be printed on a semiconductor die using a photo-mask in the lithographic process; using a processor to calculate an estimated pattern using a model of the lithographic process, wherein the model of the lithographic process includes a mask pattern corresponding to the photo-mask and a model of an optical path, wherein an inverse optical calculation was used to determine the mask pattern at an object plane in the optical path based at least in part on the target pattern at an image plane in the optical path and the model of the optical path, and wherein the model of the optical path includes information in addition to a magnification of the optical path; and determining if positions of differences between the estimated pattern and the target pattern exceeded one or more guard bands in the set of guard bands. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A computer-program product for use in conjunction with a computer system, the computer-program product comprising a computer-readable storage medium and a computer-program mechanism embedded therein for verifying a lithographic process, the computer-program mechanism including:
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instructions for defining a set of guard bands wound a target pattern, wherein the target pattern is to be printed on a semiconductor die using a photo-mask in the lithographic process; instructions for calculating an estimated pattern using a model of the lithographic process, wherein the model, of the lithographic process includes a mask pattern corresponding to the photo-mask and a model of an optical path, wherein an inverse optical calculation was used to determine the mask pattern at an object plane in the optical path based at least in part on the target pattern at an image plane in the optical path and the model of the optical path, and wherein the model of the optical path includes information in addition to a magnification of the optical path; and instructions for determining if positions of differences between the estimated pattern and the target pattern exceeded one or more guard bands in the set of guard bands.
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20. A computer system, comprising:
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at least one processor; at least one memory; and at least one program module, the program module stored in the memory and configured to be executed by the processor, wherein at least the program module is for verifying a lithographic process, at least the program module including; instructions for defining a set of guard bands around a target pattern, wherein the target pattern is to be printed on a semiconductor die using a photo-mask in the lithographic process; instructions for calculating an estimated pattern using a model of the lithographic process, wherein the model of the lithographic process includes a mask pattern corresponding to the photo-mask and a model of an optical path, wherein an inverse optical calculation was used to determine the mask pattern at an object plane in the optical path based at least in part on the target pattern at an image plane in the optical path and the model of the optical path, and wherein the model of the optical path includes information in addition to a magnification of the optical path; and instructions for determining if positions of differences between the estimated pattern and the target pattern exceeded one or more guard bands in the set of guard bands.
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21. A computer system, comprising:
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means for computing; means for storing; and at least one program module mechanism, the program module mechanism stored in at least the means for storing and configured to be executed by at least the means for computing, wherein at least the program module mechanism is for verifying a lithographic process, at least the program module mechanism including; instructions for defining a set of guard bands around a target pattern, wherein the target pattern is to be printed on a semiconductor die using a photo-mask in the lithographic process; instructions for calculating an estimated pattern using a model of the lithographic process, wherein the model of the lithographic process includes a mask pattern corresponding to the photo-mask and a model of an optical path, wherein an inverse optical calculation was used to determine the mask pattern at an object plane in the optical path based at least in part on the target pattern at an image plane in the optical path and the model of the optical path, and wherein the model of the optical path includes information in addition to a magnification of the optical path; and instructions for determining if positions of differences between the estimated pattern and the target pattern exceeded one or more guard bands in the set of guard bands.
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22. A computer-implemented method for verifying a semiconductor-manufacturing process, comprising:
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defining a set of guard bands around a target pattern, wherein the target pattern is to be printed on a semiconductor die using a write device in the semiconductor-manufacturing process; using a processor to calculate an estimated pattern using a model of the semiconductor-manufacturing process, wherein the model of the semiconductor-manufacturing process includes a write pattern for the write device, wherein an inverse optical calculation was used to determine the write pattern at an object plane of the write device based at least in pad on the target pattern at an image plane in the write device and the model of the semiconductor-manufacturing process, and wherein the model of the optical path includes information in addition to a magnification of the optical path; and determining if positions of differences between the estimated pattern and the target pattern exceeded one or more guard bands in the set of guard bands.
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Specification