To obtain a thin-film transistor(TFT) substrate free from bright point defects without changing production stages by providing the above process with a stage for providing TFT regions and regions covering at least light shielding patterns with a-Si and a stage for etching regions for etching away the residues of this a-Si.

First wiring groups 1 are formed of metallic films on a glass substrate. In this case, the light shielding patterns 2 are formed in the same stage. Next, an insulating film 9 and an a-Si film are continuously formed and the TFT part a-Si films 10 forming the TFTs are formed by plasma CVD, etc. Further, the films to allow the a-Si to remain are simultaneously formed. Next, a resist is applied therein and is subjected to exposing and developing in a PR stage for forming contact holes for connecting the first wiring groups 1 and the upper layer metal. The photoresist 11 is bored with slits for trenches for the purpose of cutting the a-Si layer. This substrate is etched by a drying etching device.