Charged particle image inspection
An unknown defect type cannot be identified or classified by existing defect classification techniques. An improved defect classification method includes obtaining an inspection image of a wafer resulting from a lithography process, obtaining layout data associated with the inspection image, obtaining a probability map derived from the layout data, wherein the probability map identifies a probability of a first defect type resulting from the lithography manufacturing process occurring in a region of the layout data, identifying a potential defect in the inspection image occurring at a first location, evaluating a confidence score for the potential defect, based on a threshold corresponding to a known defect type, indicating the potential defect as an unknown defect type if the confidence score does not satisfy the threshold, and classifying the unknown defect type based on the probability map and the first location.
1 . A system comprising:
a memory storing a set of instructions; and
at least one processor configured to execute the set of instructions to cause the system to perform:
obtaining an inspection image of a wafer resulting from a lithography manufacturing process;
obtaining layout data associated with the inspection image;
obtaining a probability map derived from the layout data wherein the probability map identifies a probability of a first type of defect resulting from the lithography manufacturing process occurring in a region of the layout data;
identifying a potential defect resulting from the lithography manufacturing process in the inspection image occurring at a first location;
evaluating a confidence score for the potential defect based on a threshold corresponding to a known defect type;
indicating the potential defect as an unknown defect type if the confidence score does not satisfy the threshold; and
classifying the unknown defect type based on the probability map and the first location.
2 . The system of claim 1 , wherein, in classifying the unknown defect type, the at least one processor is configured to execute the set of instructions to further cause the system to perform:
classifying the unknown defect type as the first type of defect when the first location corresponds to the region of the layout data.
3 . The system of claim 2 , wherein, in classifying the unknown defect type, the at least one processor is configured to execute the set of instructions to further cause the system to perform:
determining the probability that the unknown defect type is above a threshold probability of being the first type of defect; and
in response to a determination that the probability is below the threshold probability, classifying the unknown defect type as a new defect type.
4 . The system of claim 1 , wherein the first type of defect is one of a predetermined set of known defect types.
5 . The system of claim 1 , wherein the first type of defect is one of a hard bridge defect, a soft bridge defect, a hard break defect, a soft break defect, a line-end pullback defect, or a particle defect.
6 . The system of claim 1 , wherein, in evaluating the confidence score, the at least one processor is configured to execute the set of instructions to further cause the system to perform:
evaluating the confidence score based on a threshold corresponding to a known defect type among a predetermined set of known defect types.
7 . The system of claim 1 , wherein the layout data is in Graphic Database System (GDS) format, Graphic Database System II (GDS II) format, Open Artwork System Interchange Standard (OASIS) format, or Caltech Intermediate Format (CIF).
8 . A non-transitory computer readable medium that stores a set of instructions that is executable by at least one processor of a computing device to cause the computing device to perform a method of defect classification, the method comprising:
obtaining an inspection image of a wafer resulting from a lithography manufacturing process;
obtaining layout data associated with the inspection image;
obtaining a probability map derived from the layout data wherein the probability map identifies a probability of a first type of defect resulting from the lithography manufacturing process occurring in a region of the layout data;
identifying a potential defect resulting from the lithography manufacturing process in the inspection image occurring at a first location;
evaluating a confidence score for the potential defect based on a threshold corresponding to a known defect type;
indicating the potential defect as an unknown defect type if the confidence score does not satisfy the threshold; and
classifying the unknown defect type based on the probability map and the first location.
9 . The non-transitory computer readable medium of claim 8 , wherein, in classifying the unknown defect type, the set of instructions that is executable by at least one processor of the computing device to cause the computing device to further perform:
classifying the unknown defect type as the first type of defect when the first location corresponds to the region of the layout data.
10 . The non-transitory computer readable medium of claim 9 , wherein the set of instructions that is executable by at least one processor of the computing device to cause the computing device to further perform:
determining the probability that the unknown defect type is above a threshold probability of being the first type of defect; and
in response to a determination that the probability is below the threshold probability, classifying the unknown defect type as a new defect type.
11 . The non-transitory computer readable medium of claim 8 , wherein the first type of defect is one of a predetermined set of known defect types.
12 . The non-transitory computer readable medium of claim 8 , wherein the first type of defect is one of a hard bridge defect, a soft bridge defect, a hard break defect, a soft break defect, a line-end pullback defect, or a particle defect.
13 . The non-transitory computer readable medium of claim 8 , wherein, in evaluating the confidence score, the set of instructions that is executable by at least one processor of the computing device to cause the computing device to further perform:
evaluating the confidence score based on a threshold corresponding to a known defect type among a predetermined set of known defect types.
14 . A method of defect classification comprising:
obtaining an inspection image of a wafer resulting from a lithography manufacturing process;
obtaining layout data associated with the inspection image;
obtaining a probability map derived from the layout data, wherein the probability map identifies a probability of a first type of defect resulting from the lithography manufacturing process occurring in a region of the layout data;
identifying a potential defect resulting from the lithography manufacturing process in the inspection image occurring at a first location;
evaluating a confidence score for the potential defect based on a threshold corresponding to a known defect type;
indicating the potential defect as an unknown defect type if the confidence score does not satisfy the threshold; and
classifying the unknown defect type based on the probability map and the first location.
15 . The method of claim 14 , wherein classifying the defect further comprises:
classifying the unknown defect type as the first type of defect when the first location corresponds to the region of the layout data.
16 . The method of claim 15 , wherein classifying the unknown defect type further comprises:
determining the probability that the unknown defect type is above a threshold probability of being the first type of defect; and
in response to a determination that the probability is below the threshold probability, classifying the unknown defect type as a new defect type.
17 . The method of claim 14 , wherein the first type of defect is one of a predetermined set of known defect types.
18 . The method of claim 14 , wherein the first type of defect is one of a hard bridge defect, a soft bridge defect, a hard break defect, a soft break defect, a line-end pullback defect, or a particle defect.