Gate lines are formed on a substrate. A gate insulating layer, an intrinsic a-Si layer, an extrinsic a-Si layer, a lower film of Cr and an upper film of Al containing metal are sequentially deposited. A photoresist having thicker first portions on wire areas and thinner second portions on channel areas is formed on the upper film. The upper film on remaining areas are wet-etched, and the lower film and the a-Si layers on the remaining areas are dry-etched along with the second portions of the photoresist. The upper film, the lower film, and the extrinsic a-Si layer on the channel areas are removed. The removal of the upper film and the lower film on the channel areas are performed by wet etching, and the first portions of the photoresist are removed after the removal of the upper film on the channel areas.