US 11,899,380 B2
Apparatus for and method of sensing alignment marks
Krishanu Shome, Cheshire, CT (US); Igor Matheus Petronella Aarts, Port Chester, NY (US); and Junwon Lee, Weston, CT (US)
Assigned to ASML Holding N.V., Veldhoven (NL)
Appl. No. 17/770,575
Filed by ASML Holding N.V., Veldhoven (NL)
PCT Filed Sep. 28, 2020, PCT No. PCT/EP2020/077141
§ 371(c)(1), (2) Date Apr. 20, 2022,
PCT Pub. No. WO2021/078474, PCT Pub. Date Apr. 29, 2021.
Claims priority of provisional application 62/923,735, filed on Oct. 21, 2019.
Prior Publication US 2022/0291598 A1, Sep. 15, 2022
Int. Cl. G03F 7/20 (2006.01); G03F 9/00 (2006.01); G01J 9/02 (2006.01)
CPC G03F 9/7046 (2013.01) [G01J 9/02 (2013.01); G03F 9/7049 (2013.01); G03F 9/7088 (2013.01); G01J 2009/028 (2013.01)] 18 Claims
OG exemplary drawing
 
1. An apparatus for sensing an alignment mark on a substrate, the apparatus comprising:
a sensor comprising a self-referencing interferometer having a field of view at the substrate larger than the alignment mark and configured to receive light diffracted by the alignment mark and adapted to generate an output comprising at least one standing output image of the alignment mark as the alignment mark is scanned;
a detector adapted to detect a phase signal in the output;
a camera adapted to capture an image of the output;
an optical device configured to receive the output and adapted to convey the output to the detector and the camera; and
a processor configured to receive data from the camera and adapted to perform image manipulation on the data, wherein the image manipulation comprises setting a digital aperture that is one of an arbitrary shape, modulated, or apodized.