Reduced Process Method for Thin-Film-Transistor Liquid-Crystal Display (TFT-LCD) with Dry-Etching Tapered ITO Data Bus Lines

For years, many studies have been conducted for the purpose of reducing the number of TFT processes. We have developed a top-gate TFT-LCD fabricated using only indium-tin-oxide (ITO: In2O3-SnO2) data bus lines by eliminating the metal data bus line process. Substituting ITO dry-etching for wet-etching allows tapering of the side walls of thick ITO data bus lines. Controlling the tapered angle of ITO data bus lines to be less than 40° results in successful fabrication of a transistor with no offset voltage. As a result, we have developed a 6-inch-diagonal TFT-LCD fabricated with data bus lines as well as drain-source electrodes of single-layered ITO.