a substrate, wherein a first metal layer and a first insulating layer are disposed sequentially on the substrate, the first insulating layer comprises a first region and a second region adjacent to the first region, and a thickness of the second region is less than a thickness of the first region;

an oxide semiconductor layer disposed on a surface of the first region of the first insulating layer away from the first metal layer, wherein a projection of at least a portion of the oxide semiconductor layer projected on the substrate overlaps with a projection of the first metal layer projected on the substrate;

a second insulating layer disposed on a surface of the oxide semiconductor layer away from the first insulating layer, wherein a second metal layer and a third insulating layer are disposed sequentially on the second insulating layer, the third insulating layer covers the second metal layer, the second insulating layer, the oxide semiconductor layer, and the first insulating layer; and

a third metal layer disposed on a surface of the third insulating layer away from the second metal layer, wherein the third metal layer is electrically connected to the oxide semiconductor layer through a first via hole and a second via hole, the third metal layer is connected to the first metal layer through a third via hole in the second region, and the third via hole is extended through the first insulating layer and the third insulating layer.