A method for manufacturing a thin film transistor array panel includes forming a gate line and a gate electrode protruding from the gate line on a substrate; forming a gate insulating layer on the gate line and the gate electrode; depositing sequentially a semiconductor material and a metal material on the gate insulating layer; performing a first etching operation on the semiconductor material and the metal material using a first mask to form a semiconductor layer and a metal layer, the metal layer including a data line, a source electrode, and a drain electrode, in which the drain electrode protrudes from the data line, and the source electrode and the drain electrode having an integral shape; and performing a second etching operation on the metal layer using a second mask to divide the source electrode and the drain electrode.