US 11,531,280 B2Granted

Compact alignment sensor arrangements

AssigneesASML Holding N.V., ASML Netherlands B.V.

InventorsTamer Mohamed Tawfik Ahmed Mohamed Elazhary, Justin Lloyd Kreuzer, Franciscus Godefridus Casper Bijnen, Krishanu Shome

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Abstract

An apparatus and system for determining alignment of a substrate in which a periodic alignment mark is illuminated with spatially coherent radiation which is then provided to a compact integrated optical device to create self images of the alignment mark which may be manipulated (e.g., mirrored, polarized) and combined to obtain information on the position of the mark and distortions within the mark. Also disclosed is a system for determining alignment of a substrate in which a periodic alignment mark is illuminated with spatially coherent radiation which is then provided to an optical fiber arrangement to obtain information such as the position of the mark and distortions within the mark.

Claims18

Dependent claims

An apparatus for sensing an alignment pattern comprising a grating on a substrate, the apparatus comprising:

at least one light source configured to generate a first beam of coherent radiation illuminating a portion of the grating from a first angle and a second beam of coherent radiation illuminating the portion of the grating from a second angle, the first and second beams being diffracted by the portion of the grating;
and
a multimode interference device comprising:
a first input port arranged to receive a positive diffraction order of the first beam and a positive diffraction order of the second beam as diffracted by the grating portion;
a second input port arranged to receive a negative diffraction order of the first beam and a negative diffraction order of the second beam as diffracted by the grating portion;
a first output port arranged to output a first spatially overlapped image comprising an image of the grating portion as illuminated by the first beam and a mirror image of the grating portion as illuminated by the second beam;
and
a second output port arranged to output a second spatially overlapped image comprising an image of the grating portion as illuminated by the second beam and a mirror image of the grating portion as illuminated by the first beam.

5 more elements

An apparatus for sensing an alignment pattern comprising a grating on a substrate, the apparatus comprising:

at least one light source configured to generate a first beam of coherent radiation illuminating a portion of the grating from a first angle and a second beam of coherent radiation illuminating the portion of the grating from a second angle, the first and second beams being diffracted by the portion of the grating;
and
a plurality of multimode interference devices, each of the multimode interference devices being arranged adjacent to a respective segment of the grating portion and comprising:
a first input port arranged to receive a positive diffraction order of the first beam and a positive diffraction order of the second beam as diffracted by the respective segment of the grating portion;
a second input port arranged to receive a negative diffraction order of the first beam and a negative diffraction order of the second beam as diffracted by the respective segment of the grating portion;
a first output port arranged to output a first spatially overlapped image comprising an image of the segment of the grating portion as illuminated by the first beam and a mirror image of the segment of the grating portion as illuminated by the second beam;
and
a second output port arranged to output a second spatially overlapped image comprising an image of the segment of the grating portion as illuminated by the second beam and a mirror image of the segment of the grating portion as illuminated by the first beam.

5 more elements

An apparatus for sensing an alignment pattern comprising a grating on a substrate, the apparatus comprising:

at least one light source configured to generate a first beam of coherent radiation illuminating a portion of the grating from a first angle and a second beam of coherent radiation illuminating the portion of the grating from a second angle, the first and second beams being diffracted by the portion of the grating;
and
a plurality of optical fiber based devices each arranged adjacent to a respective segment of the grating portion and comprising:
a first input port arranged to receive a positive diffraction order of the first beam and a positive diffraction order of the second beam as diffracted by the grating portion;
a second input port arranged to receive a negative diffraction order of the first beam and a negative diffraction order of the second beam as diffracted by the grating portion;
a first output port arranged to output a first spatially overlapped image comprising a p-polarized image from the negative diffraction orders and an s-polarized image from the positive diffraction orders;
and
a second output port arranged to output a second spatially overlapped image comprising an s-polarized image from the negative diffraction orders and order sand a p-polarized image from the positive diffraction orders.

5 more elements

Dependencies are inferred from the claim text.

Facts

Application: 17/271,684Filed 22 Aug 2019 · us provisional application
Priority: 29 Aug 2018
Published: US 2021/0318627 A114 Oct 2021
Granted: 20 Dec 2022
Term ends: Not estimatedThe source records don’t support an estimate.

Classification5 codes

G03F 9/7088
For microlithography: alignment mark detection, e.g. TTR, TTL, off-axis detection, array detector, video detection
G03F 7/70775
Handling of masks or workpieces: position control, e.g. interferometers or encoders for determining the stage position
G03F 9/7049
For microlithography: technique, e.g. interferometric
G03F 9/7076
Alignment marks and their environment: mark details, e.g. phase grating mark, temporary mark