US 2026/0287334 A1Published application

System and method for transparent layer compensation in 3d optical metrology

AssigneeOrbotech Ltd.

InventorsElkana Porat, Nir Turko

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Abstract

An illumination subsystem includes a light source that emits light split into a reference beam and an object beam and a beam steering element that directs the object beam to a workpiece disposed on a stage. A detection subsystem includes a first beam splitter that combines the reference beam with the object beam transmitted through the workpiece or reflected by the workpiece into a combined beam and a detector that generates a detection signal based on the combined beam. A processor receives the detection signal from the detector as the stage scans relative to the object beam for a scan length, the illumination subsystem adjusts an effective illumination wavelength of the object beam for a portion of the scan length in an area of destructive interference, and the processor generates an interference image of the workpiece based on the detection signal received for the entire scan length.

Claims20

Dependent claims

A system comprising:

a stage configured to support a workpiece;
an illumination subsystem comprising:
a light source configured to emit light split into a reference beam and an object beam;
and
a beam steering element disposed in a path of the object beam, wherein the beam steering element is configured to direct the object beam to the workpiece;
a detection subsystem comprising:
a first beam splitter configured to combine the reference beam with the object beam transmitted through the workpiece or reflected by the workpiece into a combined beam;
and
a detector configured to generate a detection signal based on the combined beam received from the first beam splitter;
and
a processor in electronic communication with the illumination subsystem and the detection subsystem, wherein the processor is configured to:
receive the detection signal from the detector as the stage scans relative to the object beam for a scan length;
send instructions to the illumination subsystem to adjust an effective illumination wavelength of the object beam directed to the workpiece for a portion of the scan length in an area of destructive interference in the workpiece;
and
generate an interference image of the workpiece based on the detection signal received for the entire scan length.

12 more elements

A method comprising:

emitting light from a light source, wherein the light is split into a reference beam and an object beam;
directing, with a beam steering element, the object beam to a workpiece supported by a stage;
combining, with a beam splitter, the reference beam and the object beam transmitted through the workpiece or reflected by the workpiece into a combined beam;
generating, with a detector, a detection signal based on the combined beam received from the beam splitter;
receiving, with a processor, the detection signal from the detector as the stage scans relative to the object beam for a scan length;
adjusting an effective illumination wavelength of the object beam directed to the workpiece for a portion of the scan length in an area of destructive interference in the workpiece;
and
generating, with the processor, an interference image of the workpiece based on the detection signal received for the entire scan length.

5 more elements

Dependencies are inferred from the claim text.