Abstract: A method for forming contact holes is applied in a transistor array substrate. The transistor array substrate includes first contact pads, second contact pads located over the first contact pads, a first insulation layer covering the first contact pads, and a second insulation layer covering the second contact pads. Firstly, a photoresist pattern layer having recesses and first openings is formed on the second insulation layer. The first openings expose the second insulation layer partially. Then, the first insulation layer and the second insulation layer inside the first openings are removed partially, to expose the first contact pads. Then, the thickness of the photoresist pattern layer is reduced, so that the recesses form a plurality of second openings which expose the second insulation layer partially. After that, a part of the second insulation layer which is located inside the second openings is removed, to expose the second contact pads.

Abstract: A method for forming contact holes is applied in a transistor array substrate. The transistor array substrate includes first contact pads, second contact pads located over the first contact pads, a first insulation layer covering the first contact pads, and a second insulation layer covering the second contact pads. Firstly, a photoresist pattern layer having recesses and first openings is formed on the second insulation layer. The first openings expose the second insulation layer partially. Then, the first insulation layer and the second insulation layer inside the first openings are removed partially, to expose the first contact pads. Then, the thickness of the photoresist pattern layer is reduced, so that the recesses form a plurality of second openings which expose the second insulation layer partially. After that, a part of the second insulation layer which is located inside the second openings is removed, to expose the second contact pads.