A method of manufacturing a backplane for a display device includes forming an insulation layer on a substrate, forming a pad electrode layer on the insulation layer, forming a photoresist pattern on the pad electrode layer in the pad region, etching the pad electrode layer and a portion of the insulation layer by the photoresist pattern as an etch-stop layer so as to simultaneously form a pad electrode and a side protection layer, the side protection layer covering a sidewall of the pad electrode, and stripping the photoresist pattern.