Massive overlay metrology sampling with multiple measurement columns

A multi-column metrology tool comprising:

• two or more measurement columns distributed in a two-dimensional pattern, wherein the two or more measurement columns are configured to simultaneously probe two or more measurement regions on a sample including a plurality of metrology targets, wherein measurement regions of the two or more measurement columns are distributed to cover one or more selected areas of the sample including at least some of the plurality of metrology targets, wherein a particular measurement column of the two or more measurement columns comprises:
• an illumination sub-system configured to direct illumination from at least one of one or more illumination sources to the sample;
• a collection sub-system including a collection lens configured to collect measurement signals from the sample and direct the measurement signals to one or more detectors;
• and
• a column-positioning sub-system configured to adjust a position of the collection lens within a lateral plane parallel to a sample plane for a measurement, wherein a measurement region of the particular measurement column is defined by a field of view of the collection lens and a range of the column-positioning sub-system in the lateral plane;
• wherein the column-positioning sub-systems of the two or more measurement columns adjust the positions of respective collection lenses to align with metrology targets of the plurality of metrology targets in the respective measurement regions.

A multi-column metrology method comprising:

• providing illumination to two or more measurement columns, wherein the two or more measurement columns are configured to simultaneously probe two or more measurement regions on a sample including a plurality of metrology targets, wherein a particular measurement column of the two or more measurement columns comprises:
• an illumination sub-system configured to direct illumination from at least one of one or more illumination sources to the sample;
• a collection sub-system including a collection lens configured to collect measurement signals from the sample and direct the measurement signals to one or more detectors;
• and
• a column-positioning sub-system configured to adjust a position of the collection lens within a lateral plane parallel to a sample plane for a measurement, wherein a measurement region of the particular measurement column is defined by a field of view of the collection lens and a range of the column-positioning sub-system in the lateral plane;
• directing the illumination light to the metrology targets within measurement fields of view of the two or more measurement columns;
• collecting multiplexed measurement signals by the two or more measurement columns;
• detecting the multiplexed measurement signals on the one or more detectors;
• and
• generating metrology data for the metrology targets based on the detected measurement signals.