Composite defect classifier

A computer-implemented method for classifying defects detected on a wafer, comprising:

• acquiring inspection results for the wafer using an inspection system, wherein the inspection results comprise information for defects detected on the wafer;
• and
• classifying the defects detected on the wafer by:
• inputting the information for the defects detected on the wafer into each of at least two defect classifiers included in a composite defect classifier;
• and
• for at least one of the defects that is assigned to two or more bins in the composite defect classifier, determining a bin for the at least one of the defects based on a rank assigned to the two or more bins;
• wherein the rank is assigned to the two or more bins based on one or more characteristics determined for the two or more bins,
• wherein the one or more characteristics are determined based on a comparison of predetermined defect classifications for defects in a training set and defect classifications determined for the defects in the training set by the at least two defect classifiers, and
• wherein said acquiring and said classifying are performed by a computer system.

A non-transitory computer-readable medium, storing program instructions executable on a computer system for performing a computer-implemented method for classifying defects detected on a wafer, wherein the computer-implemented method comprises:

• acquiring a training set of data for defects detected on a training wafer and defect classifications determined for the defects in the training set;
• performing two or more defect classification processes by inputting the training set of data into two or more defect classifiers;
• comparing defect classification results produced by the two or more defect classifiers to the defect classifications determined for the defects in the training set;
• determining one or more characteristics of one or more bins in the two or more defect classifiers based on results of said comparing;
• assigning a rank to the one or more bins in the two or more defect classifiers based on the determined one or more characteristics;
• selecting at least two of the two or more defect classifiers to be included in a composite defect classifier based on the rank assigned to the one or more bins;
• acquiring inspection results for the wafer using an inspection system, wherein the inspection results comprise information for defects detected on the wafer;
• and
• classifying the defects detected on the wafer by inputting the information for the defects detected on the wafer into each of the at least two defect classifiers selected to be included in the composite defect classifier and, for at least one of the defects that is assigned to two or more bins in the composite defect classifier, determining a bin for the at least one of the defects based on the rank assigned to the two or more bins.

A system configured to classify defects detected on a wafer, comprising:

• an inspection subsystem configured to acquire inspection results for the wafer, wherein the inspection results comprise information for defects detected on the wafer;
• and
• a computer subsystem configured for:
• acquiring a training set of data for defects detected on a training wafer and defect classifications determined for the defects in the training set;
• performing two or more defect classification processes by inputting the training set of data into two or more defect classifiers;
• comparing defect classification results produced by the two or more defect classifiers to the defect classifications determined for the defects in the training set;
• determining one or more characteristics of one or more bins in the two or more defect classifiers based on results of said comparing;
• assigning a rank to the one or more bins in the two or more defect classifiers based on the determined one or more characteristics;
• selecting at least two of the two or more defect classifiers to be included in a composite defect classifier based on the rank assigned to the one or more bins;
• and
• classifying the defects detected on the wafer by inputting the information for the defects detected on the wafer into each of the at least two defect classifiers selected to be included in the composite defect classifier and, for at least one of the defects that is assigned to two or more bins in the composite defect classifier, determining a bin for the at least one of the defects based on the rank assigned to the two or more bins.