A photolithography technology using light having an increasingly small wavelength to form fine semiconductor patterns on a wafer has been researched, developed and used. At the present, an apparatus using an extreme ultraviolet (EUV) light is a promising emerging technology. The technology includes applying a laser onto a target material to generate plasma and using the EUV light generated from the plasma. A core issue of the technology is the application of a droplet with a laser accurately but it may be difficult to align a droplet generator in order to apply the droplet with the laser accurately due to various mechanical reasons.