Disclosed is a method of locating systematic defects in integrated circuits. Extracting and index processing of a circuit design and feature searching are performed. During extracting and index processing, a window grid for the circuit design is established and basis patterns are merged with shapes within each. Shapes in each window are transformed into feature vectors by finding intersections between basis patterns and shapes. Feature vectors are clustered to produce an index of feature vectors. During feature searching, a defect region window of the circuit layout is identified and basis patterns are merged with shapes in the defect region window. Shapes in the defect region window are transformed into defect vectors by finding intersections between basis patterns and shapes. Feature vectors similar to the defect vector are found using representative feature vectors from the index of feature vectors. Similarities and differences between defect vectors and feature vectors are analyzed.