Method for characterizing failed circuits on semiconductor wafers
First Claim
1. A method for characterizing mapped defects associated with a plurality of semiconductor wafers which have each been subjected to a plurality of separate process operations to create a plurality of circuits in each wafer, comprising the steps of:
- determining if the mapped defects associated with each wafer are spatially clustered in separate patterns, and if so, then classifying those wafers having spatially clustered defects into groups in accordance with the manner in which the defect clusters are patterned;
determining if a relationship exists between the defects associated with the wafers in each group and the process operations performed on the wafers in such group; and
if such a relationship exists, thenidentifying which process operations gave rise to the defects associated with the wafers in each group.
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Abstract
Failed circuits (e.g., defects) on each of a plurality of semiconductor wafers (10) in a batch can be characterized for the purpose of identifying defect sources by first mapping the defective ones of the circuits (121 -12n) in each wafer. A determination is made to see if the defects in the defect pattern map associated with each wafer (10) are sufficiently clustered to warrant further study. The defect pattern maps for the wafers in the batch identified as having spatial clustering present are smoothed and thresholded to identify where spatial clusters occur. All such smoothed and thresholded defect pattern maps are separated into groups in accordance with the pattern of defects. The pattern of defects associated with each group is then analyzed to determine if any relationship exists between the pattern and the order of the process steps or one of the patterns in a library of patterns associated with particular failure modes. Should a match be found, then the particular process step(s) or failure mode(s) responsible for such defects can be indicted.
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Citations
5 Claims
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1. A method for characterizing mapped defects associated with a plurality of semiconductor wafers which have each been subjected to a plurality of separate process operations to create a plurality of circuits in each wafer, comprising the steps of:
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determining if the mapped defects associated with each wafer are spatially clustered in separate patterns, and if so, then classifying those wafers having spatially clustered defects into groups in accordance with the manner in which the defect clusters are patterned; determining if a relationship exists between the defects associated with the wafers in each group and the process operations performed on the wafers in such group; and
if such a relationship exists, thenidentifying which process operations gave rise to the defects associated with the wafers in each group. - View Dependent Claims (2, 3, 4, 5)
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Specification