A thin film transistor array panel according to an exemplary embodiment of the present invention includes: an insulating substrate; a polycrystal semiconductor layer formed on the insulating substrate; a buffer layer formed below the polycrystal semiconductor layer and containing fluorine; a gate electrode overlapping the polycrystal semiconductor layer; a source electrode and a drain electrode overlapping the polycrystal semiconductor layer and separated from each other; and a pixel electrode electrically connected to the drain electrode.