Patent ID: 11862522
Assignee: nan
Field: Optics (Instruments)
Classification: CPC H  G | IPC G  H

Claim 0:
1. An apparatus comprising:
an optical metrology tool that includes:
an optical illumination source;
optical elements;
a processing unit configured to:
select a plurality of measurement setups for a corresponding plurality of wafer regions, wherein the wafer regions are pre-determined or determined on-the-fly;
send instructions to carry out metrology measurements with one of the selected measurement setups for each corresponding wafer region using the optical metrology tool, wherein the metrology measurements are on a plurality of metrology targets on one or more wafers;
symmetrize pixel values in pupil images of the wafer regions;
modify at least one pixel value according to an average of neighboring pixel values thereby reducing noise in the pupil images;
concatenate pixels from the metrology measurements using a different one of the measurement setups;
determine metrology metric values from the concatenated pixels;
weight the concatenated pixels; and
determine measurement stability by comparing results from concatenations of different sub-sets of the metrology measurements.