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US 10,761,022 B2Granted
Rotated boundaries of stops and targets
AssigneeKLA-Tencor Corporation
InventorsTzahi Grunzweig, Alexander Svizher
Life of this patent
Estimating the term…
Abstract
A scatterometry metrology system, configured to measure diffraction signals from at least one target having respective at least one measurement direction, the scatterometry metrology system having at least one field stop having edges which are slanted with respect to the at least one measurement direction.
Claims21
A scatterometry metrology system comprising:
- a light source;
- one or more optical elements positioned to direct illumination from the light source to a target disposed on a sample, the target including at least one periodic structure including elements distributed along one or more measurement directions parallel to a surface of the sample;
- a detector located at a pupil plane;
- one or more optical elements positioned to direct radiation diffracted from the target in response to the illumination from the light source to the detector to generate a pupil plane image of the radiation diffracted from the target for one or more metrology measurements along the one or more measurement directions;
- and
- one or more field stops located at one or more planes conjugate to the sample, wherein the one or more field stops include one or more straight edges oriented to provide conjugates of the one or more straight edges on the sample along directions oblique to at least one of the one or more measurement directions to at least partially mitigate an influence of diffraction associated with the one or more straight edges on the radiation diffracted from the target in the pupil plane for the one or more metrology measurements along the one or more measurement directions.
3 more elements
A method to mitigate edge diffraction effects in metrology measurements comprising:
- receiving a target disposed on a sample, the target including at least one periodic structure including elements distributed along one or more measurement directions in a metrology system parallel to a surface of the sample, the metrology system including one or more optical elements positioned to direct illumination from a light source to the target, the metrology system further including one or more optical elements positioned to direct radiation diffracted from the target in response to the illumination from the light source to a detector located at a pupil plane to generate a pupil plane image of the radiation diffracted from the target for one or more metrology measurements along the one or more measurement directions;
- and
- providing one or more field stops located at one or more planes of the metrology system conjugate to the sample, wherein the one or more field stops include one or more straight edges oriented to provide conjugates of the one or more straight edges on the sample along directions oblique to at least one of the one or more measurement directions to at least partially mitigate an influence of diffraction associated with the one or more straight edges on the radiation diffracted from the target in the pupil plane for the one or more metrology measurements along the one or more measurement directions.
A method to mitigate edge diffraction effects in metrology measurements comprising:
- fabricating a target on a sample to include at least one periodic structure including features distributed along one or more distribution directions parallel to a surface of the sample, wherein the target includes at least one straight edge defining a boundary of the target arranged oblique to at least one of the one or more distribution directions;
- receiving the target on the sample in a metrology system, the metrology system including one or more optical elements positioned to direct illumination from a light source to the target, the metrology system further including one or more optical elements positioned to direct radiation diffracted from the target in response to the illumination from the light source to a detector located at a pupil plane to generate a pupil plane image of the radiation diffracted from the target for one or more metrology measurements along one or more measurement directions;
- and
- aligning at least one of the one or more distribution directions of the target with at least one of the one or more measurement directions of the metrology system to at least partially mitigate an influence of diffraction associated with the at least one straight edge of the target on the radiation diffracted from the target in the pupil plane image for the one or more metrology measurements along the one or more measurement directions.
1 more element
Dependencies are inferred from the claim text.