A display device includes a first substrate, and a semiconductor layer, and a gate line disposed over the first substrate. The gate line overlaps the semiconductor layer. The display device also includes a first insulating layer disposed over the semiconductor layer, wherein a first opening is formed through the first insulating layer. The display device further includes a metal pad disposed over the first insulating layer, being electrically connected to the semiconductor layer through the first opening, and a data line disposed over the first insulating layer, wherein the data line crosses the gate line. In addition, the display device includes a second insulating layer disposed over the metal pad and the first insulating layer, wherein a second opening is formed through the second insulating layer, and the second opening at least partially overlaps the gate line.