A system includes at least one tool, a storage device and a processor. The at least one tool performs semiconductor fabrication processes on at least one wafer, in which the at least one tool includes sensors. The storage device stores computer program codes. The processor executes the computer program codes in the storage device for: modeling profiles from the sensors to generate a modeling result; extracting features from the modeling result corresponding to the modeled profiles; based on the extracted features, extracting scores each representing a degree of the at least one wafer being processed by the at least one tool; and based on the extracted scores, displaying a ranking for fault detection of the at least one wafer.