Measuring a process parameter for a manufacturing process involving lithography
First Claim
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1. A method of measuring a process parameter for a manufacturing process involving lithography, comprising:
- performing first and second measurements of overlay error in a region on a substrate using respective first and second target structures; and
obtaining a measure of the process parameter based on the first and second measurements of overlay error,wherein the first and second target structures are configured such that the first measurement of overlay error is more sensitive to a perturbation in the process parameter than the second measurement of overlay error by a known amount.
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Abstract
There is disclosed a method of measuring a process parameter for a manufacturing process involving lithography. In a disclosed arrangement the method comprises performing first and second measurements of overlay error in a region on a substrate, and obtaining a measure of the process parameter based on the first and second measurements of overlay error. The first measurement of overlay error is designed to be more sensitive to a perturbation in the process parameter than the second measurement of overlay error by a known amount.
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Citations
13 Claims
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1. A method of measuring a process parameter for a manufacturing process involving lithography, comprising:
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performing first and second measurements of overlay error in a region on a substrate using respective first and second target structures; and obtaining a measure of the process parameter based on the first and second measurements of overlay error, wherein the first and second target structures are configured such that the first measurement of overlay error is more sensitive to a perturbation in the process parameter than the second measurement of overlay error by a known amount. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A non-transitory computer readable product comprising machine-readable instructions for causing a processor to perform the operations step of comprising:
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performing first and second measurements of overlay error in a region on a substrate using respective first and second target structures; and obtaining a measure of the process parameter based on the first and second measurements of overlay error, wherein the first and second target structures are configured such that the first measurement of overlay error is more sensitive to a perturbation in the process parameter than the second measurement of overlay error by a known amount.
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11. An inspection apparatus for measuring a process parameter for a manufacturing process involving lithography, comprising:
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an optical system arranged to direct radiation onto a substrate; a detector arranged to detect radiation after interaction between the radiation and the substrate; an overlay error processing module arranged to obtain a measure of overlay error by analyzing an output from the detector; and a process parameter obtaining module arranged to obtain a measure of the process parameter by causing the optical system, detector and overlay error processing module to; perform first and second measurements of overlay error in a region on the substrate using respective first and second target structures; and obtain a measure of the process parameter based on the first and second measurements of overlay error, wherein the first and second target structures are configured such that the first measurement of overlay error is more sensitive to a perturbation in the process parameter than the second measurement of overlay error by a known amount.
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12. A lithographic system comprising:
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a lithographic apparatus comprising; an illumination system arranged to illuminate a pattern; a projection optical system arranged to project an image of the pattern onto a substrate; and an inspection apparatus comprising, an optical system arranged to direct radiation onto a substrate; a detector arranged to detect radiation after interaction between the radiation and the substrate; an overlay error processing module arranged to obtain a measure of overlay error by analyzing an output from the detector; and a process parameter obtaining module arranged to obtain a measure of the process parameter by causing the optical system, detector and overlay error processing module to; perform first and second measurements of overlay error in a region on the substrate using respective first and second target structures; and obtain a measure of the process parameter based on the first and second measurements of overlay error, wherein the first and second target structures are configured such that the first measurement of overlay error is more sensitive to a perturbation in the process parameter than the second measurement of overlay error by a known amount; wherein the lithographic apparatus is arranged to use one or more process parameters measured by the inspection apparatus in applying the pattern to the substrate or further substrates.
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13. A method of manufacturing devices wherein a device pattern is applied to a series of substrates using a lithographic process, the method comprising:
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measuring a process parameter by inspecting first and second target structures formed as part of or beside the device pattern on at least one of the substrates using a method comprising, performing first and second measurements of overlay error in a region on a substrate using respective first and second target structures; and obtaining a measure of the process parameter based on the first and second measurements of overlay error, wherein the first and second target structures are configured such that the first measurement of overlay error is more sensitive to a perturbation in the process parameter than the second measurement of overlay error by a known amount; and controlling the lithographic process for later substrates in accordance with the result of the measuring of the process parameter.
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Specification