Periodic patterns and technique to control misalignment between two layers
First Claim
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1. A target for measuring the relative positions between two layers of a device, said target comprising:
- a first periodic structure over a first layer of the device; and
a second periodic structure over a second layer of the device, said second periodic structure overlying or interlaced with said first periodic structure.
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Abstract
A method and system to measure misalignment error between two overlying or interlaced periodic structures are proposed. The overlying or interlaced periodic structures are illuminated by incident radiation, and the diffracted radiation of the incident radiation by the overlying or interlaced periodic structures are detected to provide an output signal. The misalignment between the overlying or interlaced periodic structures may then be determined from the output signal.
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Citations
54 Claims
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1. A target for measuring the relative positions between two layers of a device, said target comprising:
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a first periodic structure over a first layer of the device; and
a second periodic structure over a second layer of the device, said second periodic structure overlying or interlaced with said first periodic structure. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method for making a target, comprising:
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placing a first periodic structure over a first layer of a device; and
placing a second periodic structure over a second layer of a device, wherein said second periodic structure is overlying or interlaced with said first periodic structure. - View Dependent Claims (14, 15, 16, 17, 18)
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19. A method for providing a database to determine misalignment of overlying or interlaced periodic structures, comprising:
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providing information related to thickness, refractive index, extinction coefficient, or critical dimension, and misalignment of periodic structures that overly or interlace one another;
deriving from said information data related to radiation diffracted by the structures in response to a beam of radiation; and
constructing a database correlating the misalignment and the data. - View Dependent Claims (20)
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21. A method for detecting misalignment of overlying or interlaced periodic structures, comprising:
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illuminating the overlying or interlaced periodic structures with incident radiation;
detecting diffracted radiation from the illuminated portions of the overlying or interlaced periodic structures to provide an output signal; and
determining a misalignment between the structures from the output signal. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32)
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33. An apparatus for detecting misalignment of overlying or interlaced periodic structures, comprising:
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a source providing polarized incident radiation beam to illuminate the overlying or interlaced periodic structures;
at least one analyzer collecting diffracted radiation from the structures;
at least one detector detecting diffracted radiation collected by the analyzer to provide output signals; and
a signal processor determining any misalignment between the structures from the output signals. - View Dependent Claims (34, 35, 36, 37, 38, 39, 40, 41)
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42. An apparatus for detecting misalignment of overlying or interlaced periodic structures, comprising:
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a source providing polarized incident radiation beam to illuminate the overlying or interlaced periodic structures;
two analyzers collecting first-order diffracted radiation from the structures, the first-order diffracted radiation comprising a positive first-order diffraction and a negative first-order diffraction;
a first device interfering the positive first-order diffraction and the negative first order diffraction from the analyzers to provide a combined diffracted radiation signal;
a detector detecting the combined diffracted radiation signal to provide output signals; and
a signal processor determining any misalignment between the structures from the output signals. - View Dependent Claims (43)
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44. An apparatus for making overlying or interlaced periodic structures arid detecting misalignment between the overlying or interlaced periodic structures, comprising:
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a deposition instrument to provide the overlying or interlaced periodic structures;
a source providing polarized incident radiation beam to illuminate the overlying or interlaced periodic structures;
at least one analyzer collecting diffracted radiation from the structures;
at least one detector detecting diffracted radiation collected by the analyzer to provide output signals; and
a signal processor determining any misalignment between the structures from the output signals and providing the misalignment to the deposition instrument. - View Dependent Claims (45, 46, 47, 48, 49, 50, 51, 52)
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53. An apparatus for making overlying or interlaced periodic structures and detecting misalignment between the overlying or interlaced periodic structures, comprising:
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a deposition instrument to provide the overlying or interlaced periodic structures;
a source providing polarized incident radiation beam to illuminate the overlying or interlaced periodic structures;
two analyzers collecting first-order diffracted radiation from the structures, the first-order diffracted radiation comprising a positive first-order diffraction and a negative first-order diffraction;
a first device interfering the positive first-order diffraction and the negative first order diffraction from the analyzers to provide a combined diffracted radiation signal;
a detector detecting the combined diffracted radiation signal to provide output signals; and
a signal processor determining any misalignment between the structures from the output signals and providing the misalignment to the deposition instrument. - View Dependent Claims (54)
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Specification