A liquid crystal display includes a substrate, an active layer on the substrate, the active layer having a source region, a channel region and a drain region, a gate line including a gate electrode, the gate electrode overlapping the channel region of the active layer and the gate line having a gate insulating layer disposed underneath, an insulating interlayer covering the exposed surface of the substrate including the gate line, a first contact hole and a second contact hole exposing portions of the source region and the drain region in the insulating interlayer, respectively, a data line including a source electrode on the insulating interlayer, the source electrode connected to the source region and the data line crossing over the gate line, a drain electrode on the insulating interlayer, the drain electrode connected to the drain region, a passivation layer covering the exposed surface of the substrate including the data line and the drain electrode, a third contact hole exposing a portion of the drain electrode on the passivation layer, a pixel electrode connected to the drain electrode on the passivation layer, and a first etching preventing layer covering the crossing portion of the gate lines and the data lines.
A method for fabricating a liquid crystal display device includes: forming a pixel electrode on a substrate; forming a first conductive layer on the pixel electrode; forming a first photoresist pattern on the conductive layer; forming a source electrode forming portion, a channel forming portion and a pixel electrode forming portion using the first photoresist pattern as a mask; forming a semiconductor layer over an entire surface of the substrate; forming an insulating layer on the semiconductor layer; forming a second conductive layer on the insulating layer; forming a second photoresist pattern on the second conductive layer; forming an active layer using the second photoresist pattern; and forming a gate electrode on the active layer.
A liquid crystal display device is described in which the TFTs are located directly below the spaces between pixels. The black matrix comprises an array of opaque conductive elements with one such element being above each TFT. The black matrix is incorporated into the TFT structure. By using highly conductive material for the black matrix elements their thickness is held to a minimum, thereby minimizing their impact on planarity. Optionally, this highly conductive layer may be laminated with layers of a non-reflective conductor that makes good ohmic contact to silicon. In one embodiment, metal filled via holes are added that connect the TFTs to the transparent conductive pixel control elements by way of the black matrix layer. In another embodiment, the black matrix layer is connected to be in parallel with the gate electrode, thereby reducing the series resistance of the latter. A process for manufacturing the display is also described.
The present invention improves the aperture ratio of a pixel of a reflection-type display device or a reflection type display device without increasing the number of masks and without using a blackmask. A pixel electrode (167) is arranged so as to partially overlap a source wiring (137) for shielding the gap between pixels from light, and a thin film transistor is arranged so as to partially overlap a gate wiring (166) for shielding a channel region of the thin film transistor from light, thereby realizing a high pixel aperture ratio.
An object of the present invention is to provide an active matrix type display unit having a pixel structure in which a pixel electrode formed in a pixel portion, a scanning line (gate line) and a data line are suitably arranged, and high numerical aperture is realized without increasing the number of masks and the number of processes. In this display unit, a first wiring arranged between a semiconductor film and a substrate through a first insulating film is overlapped with this semiconductor film and is used as a light interrupting film. Further, a second insulating film used as a gate insulating film is formed on the semiconductor film. A gate electrode and a second wiring are formed on the second insulating film. The first and second wirings cross each other through the first and second insulating films. A third insulating film is formed as an interlayer insulating film on the second wiring, and a pixel electrode is formed on this third insulating film. The pixel electrode can be overlapped with the first and second wirings so that an area of the pixel electrode can be increased in the display unit of a reflection type.
In a display device such as a liquid crystal display device, a large-sized display screen is realized under low power consumption. A surface of a source wiring line of a pixel portion employed in an active matrix type liquid crystal display device is processed by way of a plating process operation so as to lower a resistance value of this source wiring line. The source wiring line of the pixel portion is manufactured at a step different from a step for manufacturing a source wiring line of a drive circuit portion. Further, electrodes of a terminal portion are processed by a plating process operation so as to reduce a resistance value thereof.
