JPH0244318A - Display device - Google Patents

Abstract

PURPOSE:To cut down cost and to reduce wiring resistance and to increase a rate of performation by forming a data line and a drain of a transparent conductor and metallic layers laminated on it and by forming an picture element electrode and a source of a transparent conductor. CONSTITUTION:The data line and the drain of a thin film transistor TFT are formed of the transparent conductor 13 and the metallic layer 16 and 17 laminated on it, and the picture element electrode and the source of the TFT are formed of the transparent conductor 13. The wiring resistance of a data line is reduced without reducing the numerical aperture. I.e., the resistance of the data line and the drain concerning with the propagation of a signal are low because the metallic layers 16 and 17 are laminated on th transparent conductor 13. Besides, since the picture element which acts to display and the source electrode are formed on only the transparent conductor, the rate of perforation of the source part can be increased as a display electrode. Thus, the efficiency of display can be improved and the cost can be cut down.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to an active matrix display device.

(Prior Art) In recent years, active matrix liquid crystal display devices using thin film transistors (hereinafter abbreviated as TPT) using an amorphous silicon film (hereinafter abbreviated as A-8I film) as switching elements have been attracting attention. This is due to the availability of inexpensive glass substrates, which allow for large areas.

This is because there is a possibility that high definition, high image quality, low cost, etc. can be achieved.

FIG. 3 shows an equivalent circuit for a display using a TFT array. In this FIG. 3, 31 (3L.

31□,...31o) Address line 32 that commonly drives the gate electrodes of 'rFT 33 in the id row direction.
(32+.

32□, . . . 32rl) are data lines that send display signals to the sources of the TFvr 33 in the column direction.

TFT 33 has address line 31 and data line 32
Each drain electrode is connected to the capacitor 34 as well as the display element 35. The display element 35 is, for example, a liquid crystal or an electroluminescent element. Taking a liquid crystal display panel as an example, there is a gap between a drive circuit board on which address lines 31, data lines 32, transistors 33, and capacitors 34 are integrated, and an opposing board on which transparent electrodes are formed on the entire surface. It is constructed by sandwiching a liquid crystal layer between the two. Such a display panel is driven by a line sequential method in which data is written for each address line, and has the advantage that the display element 35 can be driven at a duty ratio of approximately 100 inches. Note that the capacitor 34 may not be attached in the above configuration.

Next, FIG. 4 shows the specific structure of this type of display. In FIG. 4, a wiring no. 2 turf 42 serving as an address line and a gate is formed on a glass substrate 41, and a gate insulating film 43 and an a-8i 44 are deposited to form an a-8i island. After forming the display electrode 45, the source 461,
A drain electrode 462 and wiring to become a data line are formed.

If this type of display is made to have a large area and high definition, there will be problems such as an increase in cost, an increase in wiring resistance, and a decrease in aperture ratio, making manufacturing difficult. In order to reduce costs, it is effective to reduce the manufacturing process, especially the mask process. For example, the source, drain, and display transparent electrode of TF'I' are manufactured from the same ITO (Japan Display 86, PD-
3). Making the 7-space (pixel electrode side) a transparent electrode in this way is effective in increasing the aperture ratio. However, ITO has a resistivity of several mΩ, which is more than an order of magnitude higher than that of metal, which has a resistivity of 10 to 100α. Therefore, for a display device with a diagonal of 10 inches, the width is 20 μm, 2 m, Qm, the thickness is 2000 A, and the length is 2
In the case of 0-son wiring, the wiring resistance is as large as IMΩ, so the pulse propagation delay is 4m5ec, which is the write time of 3
It is very large compared to a 0μ crown and cannot be driven.

(Problems to be Solved by the Present Invention) As described above, it is necessary to simultaneously solve the problems of increased cost, increased wiring resistance, and decreased aperture ratio in a display device substrate using a conventional inverted staggered TPT. was difficult. The present invention aims to simultaneously solve the above problems.

[Structure of the invention]

(Means for Solving the Problems) The present invention provides a plurality of address wirings formed on an insulating substrate, a plurality of data lines forming insulating intersections with the address wirings, and a plurality of data lines in the vicinity of these intersections. a gate located adjacent to the intersection and electrically connected to the address line, a drain electrically connected to the data line, and a drain electrically connected to the pixel electrode. In the display device, the data line and the drain are formed of a transparent conductor and a metal layer laminated thereon, and the pixel electrode and the source are formed of a transparent conductor. This is a display device.

(Function) In the present invention, the data line and the TPT drain are formed from a transparent conductor and a metal layer laminated thereon, and the pixel electrode and the TF'T source are formed from a transparent conductor, without reducing the aperture ratio. The wiring resistance of data lines can be reduced. That is, data lines and drains related to signal propagation are metal (preferably low resistance metal) on transparent conductors.
Since the layers are laminated, the data line resistance is low, and since the pixel electrode and source electrode, which have a display function, are formed only from transparent conductors, it is possible to increase the aperture ratio up to the source portion as a display electrode.

Furthermore, in the present invention, the manufacturing process can be simplified by forming the data line and drain metal layers by plating.

(Example) Hereinafter, a first example of the present invention will be described using FIG. 1. 2000^ of Ta12 was sputtered onto a glass substrate, and a gate electrode was patterned by plasma etching using CF4 and 02. Next, by plasma C' V D method, 5iOx13 was 2oooX, and-pro-8i14 was 3000AX
50OA of na-8i15 was deposited. M) 15
After depositing 50OA of
formed an island. Next, after opening a contact hole, the ITO film 16 was deposited at a thickness of 200 OA.

Ni17 was deposited at 500X and Ni/ITO was etched to form data lines, source, drain, and pixel electrodes. Next, make electrical contact to the end of the data line and add 1μ of CL118 to the data line and drain only in a Watts bath.
M plating was formed. Next, Ni on the north and pixel electrodes was etched and removed using HCt.

Next, the na-8i in the channel portion was etched by CDE to complete the TFT array. Next 5iNx19
was deposited by plasma C'VD, and then subjected to a deposition process. After removing the 5iNxlQ in the contact portion by etching, a 5ooX polyimide 20 was formed, and then rubbing orientation was performed.

A counter substrate 22 on which polyimide orientation 21 was similarly applied was adhered, and a TN liquid crystal 23 was sealed to form a liquid crystal display.

By forming such an address line, the line resistance could be greatly reduced from IMΩ to 1Ω. Further, by using such a plating process, the data line and the pixel electrode can be formed using the same mask, so the number of masks can be reduced by one. Furthermore, by removing the electrode in the source section, the aperture ratio of the pixel could be increased.

Next, FIG. 2 shows another embodiment. A-8iO islands and contact holes are formed on the glass substrate 11 in the same manner as in Example 1. Next, ■ TO film 16, Cv27
Deposit 500OA of AXAl, 28, AL/Cv
/ITO was etched to form data lines, source, drain, and pixel electrodes. Next, kl/CV on the source and pixel electrodes was etched away by patterning.

Next, a liquid crystal display was formed in the same manner as in Example 1.

By forming such an address line, the lie/resistance could be greatly reduced from IMΩ to 2Ω. Further, as in the first embodiment, the aperture ratio of the screen can be increased by removing the electric whisper in the drain section.

The metal on the upper layer of the data line is limited to At and Cu.λu,
A low resistance metal such as Ag may also be used. The intermediate metal on the ITO is not limited to Cv or Ni, but any metal with good adhesion may be used.

Further, the display is not limited to a black and white type as in this embodiment, but the same effect can be obtained with a color display equipped with a color filter.

〔Effect of the invention〕

According to the present invention, the aperture ratio can be increased, the arrangement resistance can be reduced, and the number of mask processes can be reduced, thereby improving display performance and reducing costs.

[Brief explanation of the drawing]

1 and 2 are schematic diagrams of a display device according to an embodiment of the present invention, FIG. 3 is an equivalent circuit diagram of an active matrix type display, and FIG. 4 is a schematic diagram of a conventional display device. DESCRIPTION OF SYMBOLS 11...Glass substrate, 12...Gate and address electrode, 13...A-SI, 14...Gate insulating film,
15 ・=Mo/na-8i 1 6 ・=
I T Ol 17 ·-Ni.

Claims (2)

[Claims] (1) A plurality of address wirings formed on an insulating substrate, a plurality of data lines forming intersections with the address wirings insulatively, pixel electrodes arranged near these intersections, and the intersections. a display comprising a thin film transistor disposed adjacent to the address line, the thin film transistor having a gate electrically connected to the address line, a drain electrically connected to the data line, and a source electrically connected to the pixel electrode. A display device characterized in that the data line and the drain are formed of a transparent conductor and a metal layer laminated thereon, and the pixel electrode and the source are formed of a transparent conductor. (2) A display device characterized in that the data line and drain metal layers are formed by a plating method.