Method of manufacturing thin film diode

A method of manufacturing thin film diodes incorporated in a liquid crystal display, comprising a lower electrode patterned in the shape of an island disconnected from a signal electrode, an anodic oxidation film formed on a surface of the lower electrode, and a first upper electrode and a second upper electrode which are formed so as to overlie the lower electrode via the anodic oxidation film, the second upper electrode being connected to a pixel electrode said method comprising:

• a process comprising steps of forming a lower electrode material film made of a tantalum nitride film on a substrate, forming a photoresist on the lower electrode material film, and patterning on the photoresist by applying a photolithographic treatment;
• a process of forming the lower electrode and the signal electrode by etching the lower electrode material film using the patterned photoresist as an etching mask;
• a process of forming an anodic oxidation film made of a tantalum oxide film on the surface of the lower electrode by applying the anodic oxidation treatment to the lower electrode using an anodic oxidation solution;
• a first annealing process applied annealing in a vacuum to the anodic oxidation film;
• a process of forming an upper electrode material film composed of a transparent and electrically conductive film on the entire surface of the substrate including the surface of the lower electrode with the anodic oxidation film formed thereon;
• a second annealing process applied annealing in a vacuum to the substrate with the upper electrode material film formed thereon;
• a process comprising steps of forming a photoresist on the upper electrode material film, and patterning on the photoresist by applying the photolithographic treatment;
• a process of forming the first upper electrode, the second upper electrode and the pixel electrode by etching the upper electrode material film using the patterned photoresist as an etching mask;
• a process of forming an overcoating film made of an insulation material on the entire surface of the substrate after completion of the processes described in the foregoing;
• a process comprising steps of forming a photoresist on the overcoating film, and patterning on the photoresist by applying the photolithographic treatment;
• and
• a process comprising steps of forming an opening region by etching the overcoating film, the anodic oxidation film, and the lower electrode using the patterned photoresist as an etching mask, and forming the lower electrode patterned in the shape of an island disconnected from the signal electrode.