A patterning apparatus includes a laser generator, at least one lens, a detector, and a controller. The laser generator generates a first laser beam and a second laser beam having different intensities. The at least one lens irradiates the first laser beam to form a pattern in a substrate, irradiates a second laser beam to determine a defect of the pattern, and condenses reflected beams generated as the second laser beam is reflected from the substrate. The detector converts the reflected beams to electrical signals. The controller determines a defect of the pattern based on the electrical signals.