A method of forming a metal pattern is disclosed. According to the method, a gate electrode and a pixel electrode are formed on a substrate. A metal layer is formed covering the gate electrode and the pixel electrode. A photo pattern is formed wherein a thickness of an area of the photo pattern that overlaps the gate electrode is smaller than a thickness of other areas of the photo pattern. The photo pattern is soft-baked. The photo pattern is exposed to light. The photo pattern is developed to expose a portion of the metal layer that overlaps the gate electrode. The exposed portion of the metal layer is removed to form a source electrode and a drain electrode, the source electrode and the drain electrode being spaced apart from each other with respect to the gate electrode.