A method of inspecting a wafer quality includes injecting ions into a wafer using an ion beam in an ion implantation process, collecting data about the ion beam by using a Faraday cup, extracting first data from the data about the ion beam, extracting a wafer section from the first data, calculating a feature value of a wafer from the wafer section, and evaluating a quality of the wafer by comparing the feature value with a predetermined threshold or range.