Alignment measurement system
First Claim
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1. An apparatus comprising:
- a laser source for generating an incident laser beam which is directed to a two-dimensional target grating on a target substrate such that multiple diffracted beams are created;
a beam splitter for transmitting a first plurality of the multiple diffracted beams onto a first optical path and directing a second plurality of the multiple diffracted beams onto a second optical path;
a first reference grating in the first optical path;
a first detector beyond the first reference grating in the first optical path;
a second reference grating in the second optical path; and
a second detector beyond the second reference grating in the second optical path.
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Abstract
One embodiment relates to an apparatus for alignment measurement. A laser source generates an incident laser beam which is directed to a two-dimensional target grating on a target substrate such that multiple diffracted beams are created. A beam splitter transmits a first plurality of the multiple diffracted beams onto a first optical path and directs a second plurality of the multiple diffracted beams onto a second optical path. Each of the two optical paths includes a reference grating and a detector. Another embodiment relates to a method of measuring alignment of a target substrate. Other embodiments, aspects and features are also disclosed.
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Citations
20 Claims
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1. An apparatus comprising:
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a laser source for generating an incident laser beam which is directed to a two-dimensional target grating on a target substrate such that multiple diffracted beams are created; a beam splitter for transmitting a first plurality of the multiple diffracted beams onto a first optical path and directing a second plurality of the multiple diffracted beams onto a second optical path; a first reference grating in the first optical path; a first detector beyond the first reference grating in the first optical path; a second reference grating in the second optical path; and a second detector beyond the second reference grating in the second optical path. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method of measuring alignment of a target substrate, the method comprising:
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generating an incident laser beam which is directed to a two-dimensional target grating on the target substrate such that multiple diffracted beams are created; transmitting a first plurality of the multiple diffracted beams onto a first optical path; deflecting a second plurality of the multiple diffracted beams onto a second optical path; focusing the first plurality of the multiple diffracted beams onto a first reference grating which generates a first diffraction; and focusing the second plurality of the multiple diffracted beams onto a second reference grating which generates a second diffraction. - View Dependent Claims (13, 14, 15, 16, 17, 18)
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19. An alignment measurement system comprising:
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a two-dimensional target grating on a target substrate, wherein the target grating has features spaced apart periodically along two dimensions; a laser source for generating an incident laser beam which is directed to the two-dimensional target grating such that multiple diffracted beams are created; a beam splitter for transmitting a first plurality of the multiple diffracted beams onto a first optical path and directing a second plurality of the multiple diffracted beams onto a second optical path; a first reference grating in the first optical path; a first detector beyond the first reference grating in the first optical path; a second reference grating in the second optical path; and a second detector beyond the second reference grating in the second optical path. - View Dependent Claims (20)
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Specification