Method and apparatus for detecting processing faults using scatterometry measurements

A method for characterizing a misprocessed wafer, comprising:

• providing a wafer having a grating structure;
• illuminating at least a portion of the grating structure;
• measuring light reflected from the grating structure to generate a reflection profile;
• comparing the generated reflection profile to a target reflection profile to determine a characteristic of the grating struture based on the comparison of the generated reflection profile and the target reflection profile;
• identifying a misprocessed condition of the wafer in response to the generated reflection profile being dissimilar to the target reflection profile;
• comparing the generated reflection profile to a fault classification library of reflection profiles, each reference reflection profile having an associated processing fault;
• selecting a reflection profile closest to the generated reflection profile;
• and
• characterizing the misprocessed condition of the wafer based on the processing fault associated with the selected reflection profile.

A metrology tool adapted to receive a wafer having a grating structure, comprising:

• a light source adapted to illuminate at least a portion of the grating structure;
• a detector adapted to measure light reflected from the grating structure to generate a reflection profile;
• and
• a data processing unit adapted to compare the generated reflection profile to a library of reference reflection profiles, each reference reflection profile having an associated characteristic, determine if the generated reflection profile correlates with any of the reference reflection profiles, identify a misprocessed condition of the wafer in response to the generated reflection profile not correlating with any of the reference reflection profiles, compare the generated reflection profile to a fault classification library of reflection profiles, each reference reflection profile having an associated processing fault, select a reflection profile closest to the generated reflection profile, and characterize the misprocessed condition of the wafer based on the processing fault associated with the selected reflection profile.

A metrology tool adapted to receive a wafer having a grating structure, comprising:

• a light source adapted to illuminate at least a portion of the granting structure;
• a detector adapted to measure light reflected from the grating structure to generated a reflection profile;
• and
• a data processing unit adapted to compare the generated reflection profile to a target reflection profile to determine a characteristic of the grating structure based on the comparison of the generated reflection profile and the target reflection profile, identify a misprocessed condition of the wafer in response to the generated reflection profile being dissimilar to the target reflection profile, compare the generated reflection profile to a fault classification library of reflection profiles, each reference reflection profile having an associated processing fault, select a reflection profile closest to the generated reflection profile, and characterize the misprocessed condition of the wafer based on the processing fault associated with the selected reflection profile.

A metrology tool adapted to receive a wafer having a grating structure, comprising:

• means for illuminating at least a portion of the grating structure;
• means for measuring light reflected from the grating structure to generate a reflection profile;
• means for comparing the generated reflection profile to a library of reference reflection profiles, each reference reflection profile having an associated characteristic;
• means for determining if the generated reflection profile correlates with any of the reference reflection profiles;
• means for identifying a misprocessed condition of the wafer in response to the generated reflection profile not correlating with any of the reference reflection profiles;
• means for comparing the generated reflection profile to a fault classification library of reflection profiles, each reference reflection profile having an associated processing fault;
• means for selecting a reflection profile closest to the generated reflection profile;
• and
• means for characterizing a misprocessed condition of the wafer based on the processing fault associated with the selected reflection profile.

A metrology tool adapted to receive a wafer having a grating structure, comprising:

• means for illuminating at least a portion of the grating structure;
• means for measuring light reflected from the grating structure to generate a reflection profile;
• means for comparing the generated reflection profile to a target reflection profile to determine a characteristic of the grating structure based on the comparison of the generated reflection profile and the target reflection profile;
• means for identifying a misprocessed condition of the wafer in response to the generated reflection profile being dissimilar to the target reflection profile;
• means for comparing the generated reflection profile to a fault classification library of reflection profiles, each reference reflection profile having an associated processing fault;
• means for selecting a reflection profile closest to the generated reflection profile;
• and
• means for characterizing the misprocessed condition of the wafer based on the processing fault associated with the select reflection profile.