Spatially-varying spectral metrology for local variation detection

A metrology method comprising:

• illuminating a sample with an illumination beam though one or more illumination optics including at least one of an illumination polarizer or an illumination compensator;
• collecting sample light generated in response to the illumination beam from the sample through one or more collection optics including at least one of a collection polarizer or a collection compensator;
• shearing the sample light from the one or more collection optics into two sheared beams;
• generating measurement data of the sample on a multi-pixel detector through a spectrometer, wherein the measurement data is spectrally resolved along one direction of the multi-pixel detector and has spatially varying components along an orthogonal direction of the multi-pixel detector, wherein the spatially varying components vary on a length scale smaller than a spot size of the illumination beam on the sample;
• and
• generating one or more spatially-varying metrology measurements of the sample based on the measurement data associated with one or more configurations of the one or more illumination optics and the one or more collection optics.

A metrology system comprising:

• a controller including one or more processors configured to execute program instructions causing the one or more processors to implement a metrology recipe by:
• receiving measurement data of a sample associated with one or more configurations of a spectral metrology sub-system, wherein the measurement data is generated by:
• illuminating the sample with an illumination beam though one or more illumination optics including at least one of an illumination polarizer or an illumination compensator;
• collecting sample light generated in response to the illumination beam from the sample through one or more collection optics including at least one of a collection polarizer or a collection compensator;
• shearing the sample light from the one or more collection optics into two sheared beams;
• and
• generating measurement data of the sample on a multi-pixel detector through a spectrometer;
• and
• generating one or more spatially-varying metrology measurements of the sample based on the measurement data associated with the one or more configurations of the spectral metrology sub-system.