A display panel is provided, which includes a first substrate, a first insulating layer on the first substrate, a semiconductor layer on the first insulating layer, and a second insulating layer on the semiconductor layer and the first insulating layer. The second insulating layer has a surface in contact with the first insulating layer. The second insulating layer has a first region. The first region has a thickness of 40 nm from the surface of the second insulating layer, and the second insulating layer has a fluoride ion gain ratio of 80% to 95% in the first region.