1. An automatic defect classification (ADC) method, comprising: detecting defective parts on a substrate upon which at least one semiconductor manufacturing process has been performed; and classifying defect types of the respective defective parts, wherein classifying comprises: obtaining a scanning electron microscope (SEM) image of each of the defective parts; registering information about the substrate in a graphic data system (GDS) image corresponding to each SEM image; defining a plurality of defects of interest (DOIs); defining a DOI rule for determining which defects of the defective parts comprise a DOI from among the plurality of DOIs; and analyzing the SEM image and the GDS image according to the DOI rule to classify which of the defects of the respective defective parts correspond to which of the DOIs.