1. A defect recognition system, comprising: a light source configured to project light on a wafer; a light detector configured to inspect the wafer to generate a defect map and locate at least one defect on the wafer by using the defect map; a spectrum analyzer configured to analyze the light reflected from one of the at least one defect to obtain a spectrum of the light; and a processor operatively connected to the light detector and the spectrum analyzer, wherein the processor is programmed to compare a waveform of the obtained spectrum with a plurality of waveforms respectively in spectrums of different substances to determine a composition of the defect, wherein the light detector scans the wafer by lines to generate data of lines representing light reflected from the lines of the wafer, compares a plurality of features of a sample image formed by the data of lines with a corresponding plurality of features of a reference image, and recognizes features in the sample image deviating from corresponding features of the reference image as the defect based on the comparison.