A thin film transistor array panel is disclosed. The thin film transistor array panel may include a gate line disposed on a substrate and including a gate electrode, a semiconductor layer including an oxide semiconductor disposed on the substrate, a data wiring layer disposed on the substrate and including a data line crossing the gate line, a source electrode connected to the data line and a drain electrode facing the source electrode, a polymer layer covering the source electrode and the drain electrode, and a passivation layer disposed on the polymer layer. The data wiring layer may include copper or a copper alloy and the polymer layer may include fluorocarbon.