On-the-fly scatterometry overlay metrology target

A system comprising:

• one or more controllers having one or more processors communicatively coupled to one or more metrology sub-systems, wherein the one or more processors are configured to execute a set of program instructions maintained in memory, wherein the set of program instructions is configured to cause the one or more processors to:
• receive, from one or more detectors at one or more pupil planes of the one or more metrology sub-systems, one or more signals indicative of at least one of intensity or phase variations associated with diffraction orders of an illumination beam on one or more metrology targets on a sample, wherein the one or more metrology targets of the sample include a first cell, the first cell comprising:
• a first portion of a first set of pattern elements formed along a first measurement direction in a first sample layer, wherein the first set of pattern elements comprises segmented pattern elements having a first pitch;
• a first portion of a second set of pattern elements formed along the first measurement direction in a second sample layer, wherein the second set of pattern elements comprises segmented pattern elements having a second pitch;
• and
• a first portion of a third set of pattern elements formed along the first measurement direction in the first sample layer, wherein the third set of pattern elements comprises segmented pattern elements having a third pitch;
• and
• generate an overlay error measurement between the first and second sample layers along the first measurement direction based on the signals received from the one or more metrology sub-systems associated with at least one of intensity or phase variations of diffraction orders of the illumination beam by the first portions of the first, second, and third sets of pattern elements as the sample is in motion.

A method of measuring overlay comprising:

• illuminating a sample having one or more metrology targets;
• detecting one or more signals indicative of at least one of intensity or phase variations associated with diffraction orders of an illumination beam on one or more metrology targets on a sample, wherein the one or more metrology targets of the sample include a first cell, the first cell comprising:
• a first portion of a first set of pattern elements formed along a first measurement direction in a first sample layer, wherein the first set of pattern elements comprises segmented pattern elements having a first pitch;
• a first portion of a second set of pattern elements formed along the first measurement direction in a second sample layer, wherein the second set of pattern elements comprises segmented pattern elements having a second pitch;
• and
• a first portion of a third set of pattern elements formed along the first measurement direction in first sample layer, wherein the third set of pattern elements comprises segmented pattern elements having a third pitch;
• and
• generating an overlay error measurement between the first and second sample layers along the first measurement direction based on the signals received from the one or more metrology sub-systems associated with at least one of intensity or phase variations of diffraction orders of the illumination beam by the first portions of the first, second, and third sets of pattern elements as the sample is in motion.

A method of forming a metrology target comprising:

• forming a first cell, the first cell comprising:
• a first portion of a first set of pattern elements formed along a first measurement direction in a first sample layer, wherein the first set of pattern elements comprises segmented pattern elements having a first pitch;
• a first portion of a second set of pattern elements formed along the first measurement direction in a second sample layer, wherein the second set of pattern elements comprises segmented pattern elements having a second pitch;
• and
• a first portion of a third set of pattern elements formed along the first measurement direction in the first sample layer, wherein the third set of pattern elements comprises segmented pattern elements having a third pitch, wherein at least one of intensity or phase variations of diffraction orders of an illumination beam incident by the first portions of the first, second, and third sets of pattern elements as the sample is in motion correlate to overlay between the first and second sample layers along the first measurement direction.