Abstract: The method for manufacturing a thin film transistor includes sequentially forming a gate electrode on a surface of a substrate, forming a gate insulating layer covering the surface of the substrate and the gate electrode, forming an active layer and an etching stop layer above the gate electrode, forming a metal layer including a first region covering the etching stop layer and a pair of second regions connecting both sides of the first region on the active layer, and forming a photosensitive layer on the metal layer; removing a portion of the photosensitive layer to expose a portion of the first region; removing the exposed portion of the first region with the remaining first region having a height same as the remaining photosensitive layer located at two opposite sides of the etching stop layer; and removing the remaining photosensitive layer.