Abstract: A method of detecting a fault in a semiconductor manufacturing process. The method includes obtaining measured data and reference data regarding at least one parameter related to semiconductor manufacturing conditions in a process included in a semiconductor manufacturing process during a pre-set period of time; converting the measured data and the reference data by using at least one principal component parameter obtained via principal component analysis with respect to the measured data and the reference data; calculating a similarity between the converted measured data and the converted reference data; and detecting a fault in the process based on the calculated similarity. As a result, production efficiency of a semiconductor manufacturing process may be improved.