Mapping variations of a surface
First Claim
1. A method comprising:
- dividing a surface of a sample object into pixels which are characterized by a parameter variation;
defining blocks of the surface as respective groups of the pixels;
irradiating the pixels in multiple scans over the surface and applying differently oriented, respective first polarization states to an incident radiation;
receiving returning radiation from the pixels in response to each of the scans;
analyzing at least part of the returning radiation of the scans and applying respective second polarization states to said returning radiation to generate processed returning radiation from the returning radiation;
detecting the processed returning radiation;
for each of the scans, (i) constructing respective block signatures of the blocks in response to the processed returning radiation from the group of pixels in each block; and
(ii) determining a block signature variation using the respective block signatures of the blocks; and
in response to a correlation between the block signature variation and the parameter variation, selecting one of the first polarization states and at least one of the second polarization states for use in subsequent examination of a test object such that the combination of the at least two polarization states provides an optimal sensitivity of the block signature variation.
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Abstract
A method for characterizing a surface, consisting of dividing the surface into pixels which are characterized by a parameter variation and defining blocks of the surface as respective groups of the pixels. The pixels are irradiated in multiple scans over the surface with radiation having different first polarization states. At least part of the radiation returning from the pixels is analyzed using second polarization states, to generate processed returning radiation. For each scan, block signatures of the blocks are constructed using the processed returning radiation from the group of pixels in each block. Also for each scan, a block signature variation is determined using the respective block signatures of the blocks, and, in response to the block signature variation, one of the first polarization states and at least one of the second polarization states are selected for use in subsequent examination of a test object.
39 Citations
23 Claims
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1. A method comprising:
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dividing a surface of a sample object into pixels which are characterized by a parameter variation; defining blocks of the surface as respective groups of the pixels; irradiating the pixels in multiple scans over the surface and applying differently oriented, respective first polarization states to an incident radiation; receiving returning radiation from the pixels in response to each of the scans; analyzing at least part of the returning radiation of the scans and applying respective second polarization states to said returning radiation to generate processed returning radiation from the returning radiation; detecting the processed returning radiation; for each of the scans, (i) constructing respective block signatures of the blocks in response to the processed returning radiation from the group of pixels in each block; and
(ii) determining a block signature variation using the respective block signatures of the blocks; andin response to a correlation between the block signature variation and the parameter variation, selecting one of the first polarization states and at least one of the second polarization states for use in subsequent examination of a test object such that the combination of the at least two polarization states provides an optimal sensitivity of the block signature variation. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method comprising:
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dividing a surface of a sample object into pixels which are characterized by a parameter variation; defining blocks of the surface as respective groups of the pixels; irradiating the pixels in multiple scans over the surface and applying differently oriented, respective first polarization states to an incident radiation; receiving returning radiation from the pixels in response to each of the scans; analyzing at least part of the returning radiation and applying respective second polarization states to said returning radiation to generate processed returning radiation from the returning radiation; detecting the processed returning radiation; constructing respective composite block signatures of the blocks in response to the processed returning radiation from the group of pixels in each block; determining a composite block signature variation using the composite block signatures of the blocks; and in response to a correlation between the composite block signature variation and the parameter variation, selecting two or more of the first polarization states and at least one of the second polarization states for use in subsequent examination of a test object. - View Dependent Claims (14)
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15. An apparatus comprising:
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a processor configured to; divide a surface of a sample object into pixels which are characterized by a parameter variation, and define blocks of the surface as respective groups of the pixels; and a radiation scanner configured to; irradiate the pixels in multiple scans over the surface with radiation having different, respective first polarization states, receive returning radiation from the pixels in response to each of the scans, analyze at least part of the returning radiation of the scans using respective second polarization states to generate processed returning radiation from the returning radiation, and detect the processed returning radiation, and wherein the processor is further configured to; for each of the scans, (i) construct respective block signatures of the blocks in response to the processed returning radiation from the group of pixels in each block, and (ii) determine a block signature variation using the block signatures of the blocks, and in response to a correlation between the block signature variation and the parameter variation, select one of the first polarization states and at least one of the second polarization states for use in subsequent examination of a test object.
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16. An apparatus comprising:
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a processor configured to; divide a surface of a sample object into pixels which are characterized by a parameter variation, and define blocks of the surface as respective groups of the pixels; and a radiation scanner configured to; irradiate the pixels in multiple scans over the surface with radiation having different, respective first polarization states, receive returning radiation from the pixels in response to each of the scans, analyze at least part of the returning radiation using respective second polarization states to generate processed returning radiation from the returning radiation, and detect the processed returning radiation; wherein the processor is further configured to; construct respective composite block signatures of the blocks in response to the returning radiation from the group of pixels in each block, determine a composite block signature variation using the composite block signatures of the blocks, and in response to a correlation between the composite block signature variation and the parameter variation, select two or more of the first polarization states and at least one of the second polarization states for use in subsequent examination of a test object. - View Dependent Claims (17, 18)
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19. A method comprising:
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simulating a surface of a sample object as a simulated surface, and defining simulated characteristics of the simulated surface; dividing the simulated surface into pixels which are characterized by a parameter variation; defining blocks of the simulated surface as respective groups of the pixels; simulating irradiation of the pixels in multiple scans over the simulated surface with radiation having different, respective first polarization states; simulating receiving returning radiation from the pixels in response to each of the scans; simulating analysis of at least part of the returning radiation from the scans using respective second polarization states to generate processed returning radiation from the returning radiation; simulating detection of the processed returning radiation; for each of the scans, (i) constructing respective block signatures of the blocks in response to the processed returning radiation from the group of pixels in each block; and
(ii) determining a block signature variation using the block signatures of the blocks; andin response to a correlation between the block signature variation and the parameter variation, selecting one of the first polarization states and at least one of the second polarization states for use in subsequent physical examination of a test object. - View Dependent Claims (20)
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21. A method comprising:
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simulating a surface of a sample object as a simulated surface, and defining simulated characteristics of the simulated surface; dividing the simulated surface into pixels which are characterized by a parameter variation; defining blocks of the simulated surface as respective groups of the pixels; simulating irradiation of the pixels in multiple scans over the simulated surface with radiation having different, respective first polarization states; simulating receiving returning radiation from the pixels in response to each of the scans; simulating analysis of at least part of the returning radiation from the scans using respective second polarization states to generate processed returning radiation from the returning radiation; simulating detection of the processed returning radiation; constructing respective composite block signatures of the blocks in response to the processed returning radiation from the group of pixels in each block; determining a composite block signature variation using the composite block signatures of the blocks; and in response to a correlation between the composite block signature variation and the parameter variation, selecting two or more of the first polarization states and at least one of the second polarization states for use in subsequent physical examination of a test object. - View Dependent Claims (22)
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23. A method comprising:
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providing a sample object having a variation of a parameter; dividing the surface into pixels; defining blocks of the surface as respective groups of the pixels; irradiating the pixels in multiple scans over the surface with radiation having different, respective first polarization states; for each of the scans; detecting returning radiation from the pixels by one or more detectors, wherein for at least one of the detectors, at least part of the returning radiation is passed through a polarization element configured to pass radiation having a second polarization state different from the respective first polarization states; constructing respective block signatures of the blocks in response to the returning radiation; determining a block signature variation using the respective block signatures of the blocks, thereby generating a collection of block signature variations; and selecting at least one block signature variation from among said collection to thereby provide the respective one of the first polarization states and at least one of the second polarization states for use in subsequent characterization of a surface of a target object.
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Specification