Patent ID: 8377723

Claim:
A method of manufacturing a thin-film transistor (TFT) substrate, said method comprising: preparing a substrate; forming a gate electrode on the substrate; forming a gate insulating film on the gate electrode and on a region of the substrate on which the gate electrode is not formed; forming a first amorphous silicon thin film on the gate insulating film; modifying the first amorphous silicon thin film into a first crystalline silicon thin film, by crystallizing at least a region of the first amorphous silicon thin film, the region being an upper region of the gate electrode; removing a silicon oxide layer on a surface of the first crystalline silicon thin film by (i) placing the in-process TFT substrate after said modifying, in a dry etching apparatus and (ii) dry etching the surface of the first crystalline silicon thin film; forming a second amorphous silicon thin film on the first crystalline silicon thin film; forming a photoresist on the second amorphous silicon thin film; patterning the photoresist so that a region of the photoresist corresponding to the upper region of the gate electrode remains; and patterning the first crystalline silicon thin film and the second amorphous silicon thin film by dry etching using, as a mask, the photoresist remaining in said patterning of the photoresist, wherein during the time when the first crystalline silicon thin film and the second amorphous silicon thin film are dry etched in said patterning of the first crystalline silicon thin film and the second amorphous silicon thin film, presence or absence of the silicon oxide layer in a boundary between the first crystalline silicon thin film and the second amorphous silicon thin film is detected by measuring an emission intensity of predetermined radicals in plasma for the dry etching, and (i) when the presence of the silicon oxide layer is detected, it is determined that the in-process TFT substrate after said patterning of the first crystalline silicon thin film and the second amorphous silicon thin film cannot proceed to other processes subsequent to said patterning of the first crystalline silicon thin film and the second amorphous silicon thin film, and (ii) when the absence of the silicon oxide layer is detected, it is determined that the in-process TFT substrate after said patterning of the first crystalline silicon thin film and the second amorphous silicon thin film can proceed to the other processes.