Method and system for generating programmed defects for use in metrology measurements

A lithography tool comprising:

• an illumination source;
• a mask stage configured to secure one or more pattern masks;
• a sample stage configured to secure a sample;
• and
• a set of optics configured to direct illumination from the illumination source to the one or more pattern masks to project two or more patterns from the one or more pattern masks onto the sample,
• wherein the one or more pattern masks includes at least one array pattern containing one or more programmed defects, wherein the one or more pattern masks are configured to form a first array pattern in a first layer and a second array pattern in a second layer on the sample, wherein at least one of the first array pattern or the second array pattern contains a programmed defect to change the pattern of the first array pattern relative to the second array pattern to differentiate the first array pattern from the second array pattern.

A metrology tool comprising:

• an electron beam source configured to generate a primary electron beam;
• a sample stage configured to secure a sample;
• a set of electron-optical elements configured to direct at least a portion of the primary electron beam onto a portion of the sample;
• a detector assembly configured to detect electrons emanating from one or more portions of two or more array patterns disposed on the sample, wherein at least one of a first array pattern in a first layer or a second array pattern in a second layer of the two or more array patterns contains a programmed defect to change the pattern of the first array pattern relative to the second array pattern to differentiate the first array pattern from the second array pattern;
• and
• a controller including one or more processors, wherein the one or more processors are configured to cause the one or more processors to execute a set of program instructions contained in memory, wherein the set of program instructions are configured to cause the one or more processors to:
• receive image data associated with the two or more array patterns from the detector assembly;
• and
• determine one or more metrology parameters associated with the two or more array patterns based on the received image data.