P‐7.9: The Specification Study of Taper Angle in Metal Wire Electrode of TFT‐LCD

Abstract

The electrodes of Gate (GE) and Source & Drain (SE) in thin Film Transistor (TFT) devices which are made of metal wires are fabricated by getting patterned through WET Etching. The taper angle of these metal wires play key roles in liquid crystal display (LCD). Excessive taper angle of the metal wires after WET etching will lead to poor coverage of the insulating layer and light leakage at the edge of the metal and thus reduce the contrast of the LCD. The overlarge taper angle of the electrodes will result in a series of defects in the TFT LCD as stated above, however, the taper angle of the electrodes can not be too small. The lower taper will increase the resistance of the metal electrodes. Beyond that, the photoresist (PR) will peeling and thus the metal line disappearing if the taper angle are too small. This article mainly focus on developing the specifications of the taper angle in the GE and SE electrodes.