TFT CIRCUIT BOARD AND DISPLAY DEVICE HAVING THE SAME
The invention allows stable fabrication of a TFT circuit board used in a display device and having thereon an oxide semiconductor TFT. A TFT circuit board includes a TFT that includes an oxide semiconductor. The TFT has a gate insulating film formed on part of the oxide semiconductor and a gate electrode formed on the gate insulating film. A portion of the oxide semiconductor that is covered with the gate electrode 104 and a portion of the oxide semiconductor that is not covered with the gate electrode are both covered with a first interlayer insulating film. The first interlayer insulating film is covered with a first film 106 , and the first film is covered with a first AlO film.
1 . A method of manufacturing a TFT circuit board comprising;
forming an undercoat film formed on a substrate;
forming an oxide semiconductor layer on the undercoat film;
forming a gate insulating film on the oxide semiconductor layer;
forming a gate electrode on the gate insulating film;
forming a first interlayer insulating film on the gate electrode and the oxide semiconductor layer;
forming a first film that is directly in contact with the first interlayer insulating film;
forming a first AlO film that is directly in contact with the first film;
forming a first through hole in the first AlO film, the first film and the first interlayer insulating film by etching;
forming a planer layer on the first AlO film, and
forming a second through hole in the planer layer which is overlap the first through hole.
2 . The method of manufacturing the TFT circuit board according to claim 1 , wherein
the forming the first through hole include a first dry etching for the first AlO film, and a second dry etching for the first film and the first interlayer insulating film.
3 . The method of manufacturing the TFT circuit board according to claim 1 , wherein
the gate insulating film is formed on part of a surface of the oxide semiconductor, the surface facing the gate electrode.
4 . The method of manufacturing the TFT circuit board according to claim 1 , wherein
the gate electrode has a three-layered structure including a base metal layer, an Al alloy layer, and a capping metal layer.
5 . The method of manufacturing the TFT circuit board according to claim 1 ,
further including forming a second AlO film before the forming the first interlayer insulation film.