Methods and system for lithography calibration
First Claim
1. A method of calibrating a photolithographic system, the method being implemented by a computer, comprising:
- obtaining a plurality of measured dimensions of circuit patterns generated by the photolithographic system using a configuration of a photolithographic process, wherein the configuration of the photolithographic process includes a plurality of values of parameters related to the projection of an image associated with the circuit patterns by the photolithographic system;
generating, using the computer, a plurality of estimated dimensions of the circuit patterns using a model of the configuration of the photolithographic process;
applying a polynomial expansion that approximates changes in the estimated dimensions based on changes in values of the parameters of the configuration; and
calibrating, using the computer, the photolithographic process based on the polynomial expansion, wherein calibrating the photolithographic process includes the step of minimizing differences between the estimated and measured dimensions using an optimization algorithm, and wherein the calibrated photolithographic process includes a plurality of calculated values of the parameters.
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Abstract
A method of efficient optical and resist parameters calibration based on simulating imaging performance of a lithographic process utilized to image a target design having a plurality of features. The method includes the steps of determining a function for generating a simulated image, where the function accounts for process variations associated with the lithographic process; and generating the simulated image utilizing the function, where the simulated image represents the imaging result of the target design for the lithographic process. Systems and methods for calibration of lithographic processes whereby a polynomial fit is calculated for a nominal configuration of the optical system and which can be used to estimate critical dimensions for other configurations.
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Citations
11 Claims
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1. A method of calibrating a photolithographic system, the method being implemented by a computer, comprising:
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obtaining a plurality of measured dimensions of circuit patterns generated by the photolithographic system using a configuration of a photolithographic process, wherein the configuration of the photolithographic process includes a plurality of values of parameters related to the projection of an image associated with the circuit patterns by the photolithographic system; generating, using the computer, a plurality of estimated dimensions of the circuit patterns using a model of the configuration of the photolithographic process; applying a polynomial expansion that approximates changes in the estimated dimensions based on changes in values of the parameters of the configuration; and calibrating, using the computer, the photolithographic process based on the polynomial expansion, wherein calibrating the photolithographic process includes the step of minimizing differences between the estimated and measured dimensions using an optimization algorithm, and wherein the calibrated photolithographic process includes a plurality of calculated values of the parameters. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A device manufacturing method comprising the steps of:
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(a) providing a substrate that is at least partially covered by a layer of radiation-sensitive material; (b) providing a projection beam of radiation using an imaging system and generating a mask utilized to cause the projection beam to have a pattern in its cross-section; (c) projecting the patterned beam of radiation onto a target portion of the layer of radiation-sensitive material, wherein, generating in step (b) comprises obtaining a plurality of measured dimensions of circuit patterns generated by the imaging system using a configuration of a photolithographic process, wherein the configuration of the photolithographic process includes a plurality of values of parameters related to the projection of the patterned beam of radiation by the imaging system; generating, using the computer, a plurality of estimated dimensions of the circuit patterns using a model of the configuration of the photolithographic process; applying a polynomial expansion that approximates changes in the estimated dimensions based on changes in values of the parameters of the configuration; and calibrating, using the computer, the photolithographic process based on the polynomial expansion, wherein calibrating the photolithographic process includes the step of minimizing differences between the estimated and measured dimensions using an optimization algorithm, and wherein the calibrated photolithographic process includes a plurality of calculated values of the parameters.
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Specification