Inspection Apparatus, Inspection Method and Manufacturing Method
First Claim
1. An inspection apparatus for measuring properties of a product structure, the apparatus comprising:
- a radiation source;
an illumination optical system; and
an image detector in combination with the illumination optical system,wherein the radiation source and the illumination optical system are arranged to provide a spot of radiation on the product structure, the radiation having a wavelength less than 50 nm,wherein the image detector is arranged to capture at least one diffraction pattern formed by said radiation after scattering by the product structure, andwherein the inspection apparatus further comprises a processor arranged (i) to receive image data representing said captured diffraction pattern, (ii) to receive reference data describing assumed structural features of the product structure and (iii) to calculate from the image data and the reference data one or more properties of the product structure.
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Accused Products
Abstract
An inspection apparatus is provided for measuring properties of a non-periodic product structure (500′). A radiation source (402) and an image detector (408) provide a spot (S) of radiation on the product structure. The radiation is spatially coherent and has a wavelength less than 50 nm, for example in the range 12-16 nm or 1-2 nm. The image detector is arranged to capture at least one diffraction pattern (606) formed by said radiation after scattering by the product structure. A processor receives the captured pattern and also reference data (612) describing assumed structural features of the product structure. The process uses coherent diffraction imaging (614) to calculate a 3-D image of the structure using the captured diffraction pattern(s) and the reference data. The coherent diffraction imaging may be for example ankylography or ptychography. The calculated image deviates from the nominal structure, and reveals properties such as CD, overlay.
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Citations
23 Claims
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1. An inspection apparatus for measuring properties of a product structure, the apparatus comprising:
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a radiation source; an illumination optical system; and an image detector in combination with the illumination optical system, wherein the radiation source and the illumination optical system are arranged to provide a spot of radiation on the product structure, the radiation having a wavelength less than 50 nm, wherein the image detector is arranged to capture at least one diffraction pattern formed by said radiation after scattering by the product structure, and wherein the inspection apparatus further comprises a processor arranged (i) to receive image data representing said captured diffraction pattern, (ii) to receive reference data describing assumed structural features of the product structure and (iii) to calculate from the image data and the reference data one or more properties of the product structure. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of measuring properties of a product structure, the method comprising the steps:
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providing a spot of radiation on the product structure, the radiation having a wavelength less than 50 nm; capturing at least one diffraction pattern formed by said radiation after scattering by the product structure; receiving reference data describing assumed structural features of the product structure; and calculating from the image data and the reference data one or more properties of the product structure. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A method of manufacturing devices, comprising
forming device features and metrology targets on a series of substrates by a lithographic process, measuring properties of the metrology targets on one or more processed substrates using comprising: -
providing a spot of radiation, the radiation having a wavelength less than 50 nm; capturing at least one diffraction pattern formed by said radiation after scattering; receiving reference data describing assumed structural features; and calculating from the image data and the reference data the properties; and adjusting parameters of the lithographic process for the processing of further substrates based on the measured properties.
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22. A computer program product containing one or more sequences of machine-readable instructions for implementing method of measuring properties of a product structure, the method including operations comprising:
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providing a spot of radiation on the product structure, the radiation having a wavelength less than 50 nm; capturing at least one diffraction pattern formed by said radiation after scattering by the product structure; receiving reference data describing assumed structural features of the product structure; and calculating from the image data and the reference data one or more properties of the product structure.
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23. (canceled)
Specification