Method for manufacturing wiring, thin film transistor, light emitting device and liquid crystal display device, and droplet discharge apparatus for forming the same
View Patent ↗As a semiconductor device, specifically, a pixel portion included in a semiconductor device is made to have higher precision and higher aperture ratio, it is required to form a smaller wiring in width. In the case of forming a wiring by using an ink-jet method, a dot spreads on a wiring formation surface, and it is difficult to narrow width of a wiring. In the present invention, a photocatalytic substance typified by TiO 2 is formed on a wiring formation surface, and a wiring is formed by utilizing photocatalytic activity of the photocatalytic substance. According to the present invention, a narrower wiring, that is, a smaller wiring in width than a diameter of a dot formed by an ink-jet method can be formed.
1. A method for manufacturing a thin film transistor comprising:
forming a substance having a photocatalytic function over an insulating surface;
selectively irradiating the substance with light to be hydrophilic;
discharging a conductive material mixed with a water-based solvent to a region irradiated with the light by an ink-jet method to form a wiring;
forming a semiconductor film over the wiring;
forming a gate insulating film comprising a substance having a photocatalytic function to cover the semiconductor film;
selectively irradiating the gate insulating film with light to be hydrophilic; and
discharging a conductive material mixed into a water-based solvent to a region irradiated with the light by an ink-jet method to form a gate electrode.
2. A method for manufacturing a thin film transistor according to any one of claim 1 , further comprising the steps of:
forming an electrode connected to the wiring; and
forming a protective film by an ink-jet method to cover the semiconductor film, the gate electrode, and a part of the electrode.
3. A method for manufacturing a thin film transistor according to claim 1 , further comprising the steps of forming an electroluminescent layer and an electrode over the electroluminescent layer.
4. A method for manufacturing a thin film transistor according to claim 1 , further comprising the steps forming an orientation film, dropping a liquid crystal over the orientation film, and attaching an opposing substrate provided with an electrode, a color filter, and an orientation film.
5. A method for manufacturing a thin film transistor according to claim 1 , wherein the thin film transistor is incorporated in at least one selected from the group consisting of a video camera, a digital camera, a goggle type display, a navigation system, an audio reproducing device, a personal computer, a game machine, a personal digital assistance, and an image reproducing device.