Liquid crystal display device and a manufacturing method of the same
In the conventional manufacture method that has reduced the number of manufacture processes by forming semiconductor layers and source-drain wires for a channel-etch type insulating gate transistor in a single photo etching process using halftone exposure technology, the channel length increases when the photosensitive resin pattern used at above formation process of source-drain patterning is reduced. Hence the manufacture tolerance (margin) is small, and the yield decreases when the distance between the source wire and drain wire is shortened. This invention suggests the 4-mask process and, 3-mask process of the TN type liquid crystal display devices and IPS-type liquid crystal display devices by combining the following: streamline technology to form the already known pixel electrodes and scanning lines simultaneously; new technology to streamline the opening formation process in gate insulating layers and island formation process of semiconductor layer, using halftone exposure technology; and new technology to streamline the protective layer formation process for electrode terminals by adding halftone exposure technology to the already known anode oxidization technology for source-drain wires.
1. A liquid crystal display device, with at least the following characteristics in a liquid crystal display device that is filled with liquid crystals between 1) a primary transparent insulating substrate that aligns, in a 2-dimensional matrix, unit pixels that have on a principal plane at least 1) an insulating gate type transistor, b) scanning lines that also work as gate electrodes and signal lines that also work as source wires for the said insulated gate type transistor, and c) pixel electrodes that are connected to drain wires and d) counter electrodes formed within a specific distance from said pixel electrodes, and 2) a secondary transparent insulating substrate or color filter that faces said primary transparent insulating substrate, comprising:
I) one or more primary metal layers as scanning lines and counter electrodes on a principal plane of a primary transparent insulating substrate;
II) an island-like channel layer through a gate insulating layer above the gate electrodes;
III) a protective insulating layer narrower than the gate electrodes on the said channel layer;
IV) a plurality of openings self aligned with said island-like channel layer, on said scanning lines outside an image display area, exposing parts of the scanning lines within said openings;
V) a pair of semiconductor layers as the source-drain of the insulating gate type transistor, on said channel layer, partly overlapping with the gate electrodes;
VI) a plurality of source wires and drain wires consisting of one or more secondary metal layers and a heat resistant metal layer on said semiconductor layers, and gate insulating layer, and electrodes terminals of scanning lines consisting of secondary metal layers on said openings, and electrode terminals of signal lines comprising parts of said signal lines; and
VII) a passivation insulating layer with openings on said electrode terminals of scanning lines and signal lines, on said primary transparent insulating substrate.
2. The liquid crystal display device according to claim 1 , wherein said channel layer has no impurity doping, and said semiconductor layers are doped with impurities.
3. The liquid crystal display device according to claim 1 , wherein said gate insulating layer further comprises a plasma protecting layer underneath.
4. The liquid crystal display device according to claim 1 , wherein said protective insulating layer is a silicon nitride (SiNx) layer.
5. The liquid crystal display device according to claim 1 , wherein said secondary metal layer comprises an anode-oxidizable metal layer and said passivation insulating layer is an anodized layer thereof.
6. The liquid crystal display device according to claim 5 , wherein said anode-oxidizable metal layer is an aluminum layer.
7. The liquid crystal display device according to claim 5 , wherein said anode-oxidizable metal layer is a tantalum layer.
8. The liquid crystal display device according to claim 1 , wherein said passivation insulating layer is a photo-sensitive organic insulation layer.
9. The liquid crystal display device according to claim 1 , wherein said photo-sensitive organic insulating layer is not covered on the electrode terminals for said signal lines.