Patent ID: 11885737
Assignee: NOVA LTD.
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 0:
1. A method for use in measuring of a sample, the method consisting essentially of:
performing a first measurement by an optical unit of a patterned region of the sample, while applying a first measurement configuration of the optical unit, on a patterned region of a sample and generating a first data piece;
performing a second measurement of the patterned region of the sample by the optical unit, while applying a second measurement configuration of the optical unit, and generating a second data piece; wherein the first measurement configuration differs from the second measurement by a configuration difference; and
determining the symmetry of the one or more patterns of the patterned region of the sample based on the first data piece and the second data piece; and
wherein the configuration difference (a) comprises at least a polarization parameter of a collection channel of an optical unit, and (b) introduces a sensitivity to symmetry of the one or more patterns of the patterned region that is higher than the sensitivity to parameters that differ from the symmetry;
wherein each measurement of the first and second measurements comprises illuminating, by a light source of the optical unit, the patterned region of the sample through the illumination channel; and receiving, by a detection unit of the optical unit, light returned from the patterned region of the sample and propagated through a collection channel of the optical unit;, wherein the optical unit comprises a polarization unit that comprises a first polarization filter located in the collection channel.