Methods and system for model-based generic matching and tuning
First Claim
1. A computer-implemented method of tuning a to-be-tuned lithographic process to a reference lithographic process, comprising:
- obtaining respective lithographic process models for both the reference lithographic process and the to-be-tuned lithographic process;
identifying a set of tunable parameters of the to-be-tuned lithographic process, wherein the tunable parameters are distinct and independent from patterns on a design layout to be imaged using the to-be-tuned lithographic process;
determining responses of the to-be-tuned lithographic process model to changes in the set of tunable parameters;
determining optimal changes in the tunable parameters that cause the lithographic process models to match, wherein the step of determining optimal changes includes applying non-uniform weights to different terms on the lithographic process models; and
adjusting the model for the to-be-tuned lithographic process based on the determined optimal changes,wherein one or more of the obtaining, identifying, determining responses, determining optimal changes, and adjusting steps are implemented by the computer.
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Abstract
The present invention relates to a method for tuning lithography systems so as to allow different lithography systems to image different patterns utilizing a known process that does not require a trial and error process to be performed to optimize the process and lithography system settings for each individual lithography system. According to some aspects, the present invention relates to a method for a generic model-based matching and tuning which works for any pattern. Thus it eliminates the requirements for CD measurements or gauge selection. According to further aspects, the invention is also versatile in that it can be combined with certain conventional techniques to deliver excellent performance for certain important patterns while achieving universal pattern coverage at the same time.
66 Citations
18 Claims
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1. A computer-implemented method of tuning a to-be-tuned lithographic process to a reference lithographic process, comprising:
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obtaining respective lithographic process models for both the reference lithographic process and the to-be-tuned lithographic process; identifying a set of tunable parameters of the to-be-tuned lithographic process, wherein the tunable parameters are distinct and independent from patterns on a design layout to be imaged using the to-be-tuned lithographic process; determining responses of the to-be-tuned lithographic process model to changes in the set of tunable parameters; determining optimal changes in the tunable parameters that cause the lithographic process models to match, wherein the step of determining optimal changes includes applying non-uniform weights to different terms on the lithographic process models; and adjusting the model for the to-be-tuned lithographic process based on the determined optimal changes, wherein one or more of the obtaining, identifying, determining responses, determining optimal changes, and adjusting steps are implemented by the computer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A computer program product comprising a non-transitory computer readable medium having instructions recorded thereon, the instructions when executed by a computer implementing a method of tuning a to-be-tuned lithographic process to a reference lithographic process, the method comprising:
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obtaining respective lithographic process models for both the reference lithographic process and the to-be-tuned lithographic process; identifying a set of tunable parameters of the to-be-tuned lithographic process, wherein the tunable parameters are distinct and independent from patterns on a design layout to be imaged using the to-be-tuned lithographic process; determining responses of the to-be-tuned lithographic process model to changes in the set of tunable parameters; determining optimal changes in the tunable parameters that cause the lithographic process models to match, wherein the step of determining optimal changes includes applying non-uniform weights to different terms on the lithographic process models; and adjusting the model for the to-be-tuned lithographic process based on the determined optimal changes. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
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Specification