Liquid crystal display device and fabrication method thereof

Inactive Publication Date: 2005-01-13
HITACHI LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0070] By using a photomask having three areas having different optical transmissivities, it is possible to process drain wiring lines, source electrodes and drain electrodes and s-Si films through one photo-process for exposure and development, whereby it is possible to simplify the entire process. In addition, the number of photo-processes per TFT

Problems solved by technology

Moreover, in Japanese Patent Laid-Open No. 232409/1998, although the TFT glass substrate of a lateral electric field type, i.e., the IPS display mode, of liquid crystal display device is formed through four photo-processes, the terminals of its gate and drain wiring lines are not coated with a transparent conductive film such as Indium-Tin-Oxide (hereinafter, ITO), so that the terminals suffer the problem of electrical corrosion due to humidity.
In addition, s

Method used

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  • Liquid crystal display device and fabrication method thereof
  • Liquid crystal display device and fabrication method thereof
  • Liquid crystal display device and fabrication method thereof

Examples

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Example

[0104]FIG. 1 is a plan view showing a TFT substrate of a type according to Embodiment 1 of the invention. FIG. 2 is a cross-sectional view taken along line 2-2 of FIG. 1, showing a portion which extends from a TFT to a charge-holding capacitance portion Cstg through a pixel electrode PX. FIG. 3 is a cross-sectional view taken along line 3-3 of FIG. 1, showing a drain wiring line section. FIG. 4 is a cross-sectional view taken along line 4-4 of FIG. 1, showing a gate wiring line section. FIG. 5 is a cross-sectional view taken along line 5-5 of FIG. 1, showing a drain wiring line section. FIGS. 6A to 9B are cross-sectional views showing a fabrication method for the TFT substrate according to Embodiment 1 in the order of steps (from photoresist application to resist stripping) of a photo-process which is basically patterning, the respective steps corresponding to FIGS. 6A and 6B; 7A to 7D; 8A and 8B; and 9A and 9B.

[0105] In the TFT section of the liquid crystal display device, as show...

Example

[0138] The charge-holding capacitance Cstg of Embodiment 2 has a laminated structure consisting of an upper electrode made of the transparent conductive film ITO1 which is formed in the same process and of the same material as the pixel electrode PX and a lower electrode which is the gate wiring line GL, as in Embodiment 1. However, unlike the charge-holding capacitance Cstg of Embodiment 1, the charge-holding capacitance Cstg of Embodiment 2 has a dielectric film having a stacked structure made of the SiN gate insulating film GI and the half-etched a-Si channel film AS. In the structure of the charge-holding capacitance Cstg of Embodiment 2, the dielectric film is thin in thickness compared to the dielectric film of Embodiment 1 having a stacked structure made of the SiN gate wiring line GL and the SiN protective film. Moreover, the dielectric constant of the a-Si film is 12 which is greater than 7 of the SiN film, whereby Embodiment 2 makes it possible to form a larger charge-hold...

Example

[0143] As shown in the cross-sectional view of FIG. 14, Embodiment 3 is the same as Embodiment 2 shown in FIG. 11 in that in the section of the charge-holding capacitance Cstg, the gate wiring line GL and the gate insulating film GI are formed on the TFT transparent insulating substrate SUB1 and the a-Si channel film AS is partly formed on the gate insulating film GI. However, Embodiment 3 has a structure in which the pixel electrode PX made of the transparent conductive film ITO1 is directly connected to the gate insulating film GI via the through-hole CNS opened in the protective film PSV. The a-Si channel film AS has a structure such that it is in contact with side surfaces of the pixel electrode PX. Although the illustration of the plane structure of the section of the charge-holding capacitance Cstg is omitted, the a-Si channel film AS is removed from only the section of the through-hole CNS to the charge-holding capacitance Cstg inside the island-shaped pattern of the a-Si cha...

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Abstract

The present invention provides a novel photolithography processes using photoresist pattern having at least two areas which has different thickness from each other for a fabrication method for a liquid crystal display device having reversed staggered and channel-etched type thin film transistors, reduce a number of photolithography processes required for whole of the fabrication process of the liquid crystal display device, and improve brightness of the liquid crystal display device.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a liquid crystal display device and, for example, to one of a pair of substrates between which a liquid crystal layer is interposed, i.e., a so-called TFT substrate on which thin film transistors (hereinafter referred to as TFTs) are formed, as well as to a fabrication method for such a TFT substrate. [0003] 2. Description of the Related Art [0004] In the case of a related art liquid crystal display device, as described in Japanese Patent Laid-Open No. 202153 / 1994, its TFT substrate is fabricated by forming openings in the gate insulating film and the protective film laminated on the TFT substrate, through one photo-process (a process which includes the photolithography of forming a photomask on a work and partly removing the photomask according to a processing pattern), and carrying out patterning through a total of five photo-processes. In the TFT substrate obtained by this fabrica...

Claims

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Application Information

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IPC IPC(8): G02F1/1343G02F1/1362G02F1/1368G02F1/136G09F9/30H01L21/302H01L21/3065H01L21/336H01L29/786
CPCG02F1/134363G02F1/13458G02F1/136213G02F1/136227H01L27/1288G02F2001/13629H01L27/1255H01L27/1248G02F2001/136236G02F1/136236G02F1/13629G02F1/136
Inventor ONO, KIKUONAKAYOSHI, YOSHIAKIOKE, RYUTAROKANEKO, TOSHIKI
Owner HITACHI LTD
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