JPS6266665A - Manufacture of driving circuit substrate - Google Patents

Abstract

PURPOSE:To avoid an interlayer shortcircuit of matrix wirings by forming wirings of a driving circuit substrate for a display unit by arranging thin film switching elements in a matrix state of a metal film capable of being oxidized, when forming the substrate, and heat treating to convert the surface to an insulator layer. CONSTITUTION:When a conductor layer made of Ta is formed on a transparent insulating substrate 1 made of glass, the layer is composed of address wirings 2-1 extending longitudinally, a gate electrode 2-2 branched from the midway, and a wiring pad 2-3 disposed at the end. Then, the layer except the electrode 2-2 is subjected to an anodic oxidation to convert to an insulating film 4, another insulating film 3 is coated on the electrode 2-2, an N<+> type a-Si conductor layer 5 is mounted on the film 3, a contacting hole 3-2 is opened in the pad 2-3, and a pad electrode 8-4 is buried. Thereafter, picture element electrodes 6 are formed on the film 4, a source electrode 8-2 and a drain electrode 8-3 are formed on the layer 5, and data wirings 8-1 crossed perpendicularly to the electrode 8-2 are formed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Summary of the Invention] The present invention relates to a method for manufacturing a drive circuit board for a display device in which thin film switching elements are arranged in a matrix.

[Technical background of the invention and one point] Display devices such as electroluminescent panels, light emitting diodes, plasma panels, fluorescent display tubes, and liquid crystal panels can have thinner display parts, and are used in measuring instruments, office equipment, and other devices. There is a strong demand for use in terminal display devices such as computer computers or special display devices. Among these, electroluminescence and liquid crystal display devices using thin film transistors have attracted attention as display devices because they can reduce power consumption and cost, and have been developed in various places in recent years (for example, IEEE Trar, 5act
ion on Electron Device M
ol ED-20, No. 11. November1
973, PP995-1001). Materials for such switching transistors include crystal, polycrystal, AmoA/77X state No.8i or Cd8e, Te,
Cd8 etc. are used. Among these, thin film devices using polycrystalline semiconductors or amorphous semiconductors are capable of low-temperature processing, and active matrix devices such as switching transistors can also be formed on substrates that need to be handled at relatively low temperatures, such as glass substrates. This has brought a low-cost, large-area display device to the practical stage.

Figure @4 is an equivalent circuit of a display device using a general thin film transistor. Address distribution, f) (11) (11
1-112, 113...lln) drive the gate electrodes of the thin film transistors (13) arranged in the horizontal direction, and the data wirings (12) (121, 122, 123, 1
1 @ @ @ 12m) are #IIJ arranged vertically)
An image signal is applied to the source 'c electrode of the image register (13). Each of the thin film transistors (13) has an address wiring 41
1 (11) and the data distribution GN (12), and the pole of each drain □1 is connected to the display element (1
5) and is also connected to a capacitor (14).

The display element (15) is, for example, a liquid crystal. Taking a liquid crystal display device as an example, an address wiring (11), a data wiring (12), a transistor (13), and a capacitor (14) are integrally formed, and nine driving circuit boards and transparent electrodes facing the same are formed. It is constructed by forming it on the entire surface and sandwiching a liquid crystal layer between it and the FC substrate. In addition, recently, the ON-0FF characteristics of the thin film transistors used here have been improved, and even if there is no capacitor (14) serving as an auxiliary capacitance, the capacitance of the liquid crystal itself, which serves as the display device (15), is sufficient. The active matrix type display device is now able to retain the stored image information for a sufficiently long time, and is based on a line-sequential quantification method in which one life's worth of image data is stored for each address wiring run. By adopting this, the display element (15) can be driven at a duty ratio of approximately 100%, so that an easy-to-see image can be obtained.

By the way, this oak display panel is made in recent years.

As we move toward larger areas and higher definition2, the number of transistors will be extremely large in order to realize these large-capacity F-type active matrix substrates or large-area displays.

For example, if the address is 1,500 x the data is 20,000, 3,000,000 elements are required, and the number of intersections between address wiring and data wiring and the number of capacitors are also 30 each.
00000 pieces are required.

It is extremely difficult to manufacture a drive circuit board having such a large-scale transistor array with a high yield. The main causes of these defects are (1) electrical short circuits between multilayer interconnects or capacitors, (2) disconnections in interconnects, (
3) There may be a defect in the transistor, etc. However, if point defects in the display panel can be tolerated to some extent, disconnections in wiring and defects in transistors will not be a big problem. For example, in Figure 1, address wiring (11)
Even if the address wiring is cut at one point along the way (11)
This is because inputting signals from both directions does not affect the operation of other pixels, and it is expected that all pixels will operate normally depending on the position of the cut.

On the other hand, a short circuit between multilayer interconnections is not just a point defect, and has a significant impact on the display panel.

Moreover, although it is possible to separate the short circuit position using a laser or the like, it is necessary to know the short circuit position, which requires a huge amount of time to check for disconnection and inspect for differences. Furthermore, since the number of steps for separating short-circuited parts is increased, productivity is unavoidably lowered. In this way, short-circuit defects occur because the glabella insulating film is different from a thermally oxidized film of crystalline silicon and must be formed at low temperatures by sputtering or CVD.

This is due to the very poor quality of the film, and it is expected that the number will increase considerably as display panels become larger in area. Furthermore, in order to eliminate these defects, attempts have been made to form an interlayer insulating film by an anodic oxidation method. However, forming a transistor using an oxide film made only by the anodic oxidation method has problems such as large variations in characteristics. The present invention provides a method for manufacturing a drive circuit board that can solve the problems and effectively prevent short circuits between ji and j in multilayer wiring, thereby improving the yield and reliability of display panels.

[Summary of the invention]

That is, in the present invention, first, a first conductor layer and a first insulating film are sequentially deposited on an insulating substrate, and then the Jl insulating film is processed to form a desired pattern. Thereafter, the first conductive layer exposed on the surface is oxidized to form a second insulating film, and address wiring and gate electrodes are created from the first conductive layer covered with the first insulating film pattern. A semiconductor thin film pattern 7 is formed with the pixel '' using a transparent conductive film as a pole, a region T/c on the gate electrode, and partially overlapping the first insulating film and the second insulating film.

Then, the data wiring perpendicular to the address wiring,
A north pole extending from a desired location of this data wiring and overlapping a part of the semiconductor thin film pattern 7, and a drain electrode connected to this semiconductor thin film pattern on the one hand and the pixel electrode on the other hand are formed. A drive circuit board can be obtained.

〔Effect of the invention〕

According to the present invention, even if pinholes exist in the first insulating film, the first conductive layer exposed by the pinholes is
IJ has a multilayer wiring structure and serves as an insulating film.
It is possible to prevent the glabella short circuit defect of the Fuchs wire.

It is possible to improve the yield and reliability of this ninth display panel.

[Embodiments of the invention]

FIGS. 1(a) to (15) are plan views showing the manufacturing process of the present invention.

Further, FIG. 2 shows a cross-sectional view of a display device drive circuit board obtained by the manufacturing method of the present invention. An embodiment of the present invention will be described below with reference to FIGS.

First, a first conductor 1 made of a Ta film with a thickness of about 20,000 mm is placed on a transparent insulating substrate (1) such as a glass plate. !
(2) is deposited by sputtering. Next, a first insulating film (3) made of approximately 200 OA of silicon oxide g (8i02) is formed by, for example, a CVD method or a sputtering method using plasma, light, microwaves, heat, etc.
Attach. Next, a desired photoresist pattern is formed and the first resist dd (3) is etched. After that, this photoresist is removed, and the first conductive layer (2) not covered with the pattern of the first SM film (3) is removed from the surface of the insulating substrate using, for example, a boric acid-based molten tel. (1) Apply positive TFJ up to the surface and apply the second insulation 1
11(4), the first conductor layer covered with the pattern of the first insulating film (3) is the address wiring (2-
1), gate 1 pole (2-2) and this address arrangement! (2-
Figure 1 (a)) where wiring pads (2-3) around the substrate in 1) are made.

Next, a new photoresist is formed and the wiring pads (2-3
) on the first insulating film (3) to open a contact hole (3-2) of a predetermined size [Fig.
b)].

Next, undoped amorphous silicon (a-8i) with a thickness of about 300 OA was deposited by plasma CVD.
001 Norine doped amorphous silicon (n”a
A semiconductor layer (5) consisting of a continuous layer of -8i) is deposited and CDI is applied using photoresist so as to remain only in the device area.
(Chemical dry etching) [Figure 1 (C)].

Next, a transparent conductive layer such as ITO (inodium tin oxide) is deposited to a thickness of about 1000 by sputtering or E-Gun deposition, and a pixel electrode (6) is formed using a similar photoresist. (d)].

After this, a thickness of approximately 5 mm is applied using vacuum evaporation method or sputtering method.
ooX Mo and aluminum with a thickness of about 1 μm are continuously deposited, and a source electrode (8-2) is formed using photoresist.
and the address wiring (2-1), which is perpendicular to the data wiring (8-1), and the drain electrode (8-3), which overlaps the semiconductor thin film pattern (5) and connects to the pixel electrode (6).
)make. At this time, a pad electrode (8-4) made of this metal film is also formed in the address wiring wiring pad (2-3) portion around the substrate, thereby completing the display device drive circuit board 13''. "t"n, aCg"
II(e) FIG. 3 is a sectional view showing one pixel of a display device drive circuit board according to another embodiment of the present invention.

□ 1''.I''ra''absolute''property''('')1'.
2゜□. (9) (t*i)L', 2) tJ'@rA7°turning to form address wiring (2-1), gate electrode (2-2), and wiring pad (2-3). put. Thereafter, based on the above-mentioned ninth embodiment, a step of sequentially depositing a first conductive layer and a first insulating film, and a step of sequentially depositing the first insulating film (
3) forming a first insulating film pattern (3-1) matching the pattern of the second conductor layer (9), and then oxidizing the conductor layer (2); A process of forming a semiconductor thin film pattern (5) in the area above the gate electrode (2-2), a process of forming a pixel electrode (6) at a predetermined position, and a process of forming a data wiring (8-1) and a source. By performing the steps of forming the electrode (8-2), drain electrode (8-3), and pad electrode (8-4), the display device drive circuit board can be completed.

Note that the first conductive layer used in the embodiments of the present invention is not limited to Tag but may be any other material as long as it is a metal that can be anodized and has excellent light transmittance when formed into an oxide film. Metal may also be used.

Further, this oxidation means is not limited to the anodic oxidation method, and a thermal oxidation method or the like may be used in combination.

Furthermore, the opening of the first insulating film on the wiring pad of the address wiring may be performed after forming the pixel electrode made of a transparent conductive film or after processing the semiconductor thin film pattern.

In addition, the first insulating film is limited to 5tO2, SiNx or Ag2.
Other insulating films such as O3 may also be used.

Furthermore, the embodiment shown in FIG. 3 is particularly effective in reducing the resistance of the address wiring on a large-area board, and in such a case, the second conductor layer is connected to the address wiring (2-1) and the wiring. It is used for the pad (2-3), but the gate is used for the pole (2-2).
) does not need to be created.

In short, the present invention prevents short circuits between wirings of a drive circuit board for an active matrix display device by separating an oxidizable metal film into a wiring body and an insulator by oxidizing it in a desired pattern. It is something.

[Brief explanation of drawings]

The first prisoner is a display device drive circuit board according to the present invention]
of! ! FIG. 2 is a plan view of a process showing an example of the
The figure is a cross-sectional view showing one pixel of a display device drive circuit board obtained by the manufacturing method of the present invention. Figures 1 to 3 are cross-sectional views showing other embodiments of the present invention. Figure 4: is a general FIG. 3 is an equivalent circuit diagram of a display device using thin film transistors. 1...ig3 edge base i 2...first conductor layer j 2-1...address wiring '2-2 11. Ge-) 4 poles, 2-3-61. @, : , C1 3...
・First insulating film 3-1...First insulating film pattern 3-2...Contact hole 4...Second insulating film 5...Semiconductor thin film pattern 6...Pixel electrode 7・...Ohmic electrode 8-1...Data wiring 8-2...Source electrode 8-3...Drain electrode 8-4...Pad electrode 9...Second conductor layer

Claims (4)

[Claims] (1) A step of sequentially depositing a first conductive layer and a first insulating film on one main surface of an insulating substrate, and a step in which the first insulating film covers the surfaces of the address wiring and the gate electrode. oxidizing the first conductor layer other than under the first insulating film pattern to form a second insulating film; and forming a desired pattern of the first insulating film on the address wiring. forming a pixel electrode made of a transparent conductive film; and forming a semiconductor thin film pattern on a first insulating film whose main region is above the gate electrode. a data line perpendicular to the address line; a source electrode extending from a desired location of the data line and in contact with a part of the semiconductor thin film pattern; and a source electrode connected to the semiconductor thin film pattern on the one hand and a pixel electrode on the other hand. 1. A method of manufacturing a drive circuit board, comprising the steps of forming an electrode on a drain electrode for connection and an opening in an insulating film on the address wiring. (2) The method for manufacturing a drive circuit board according to claim 1, wherein the means for oxidizing the first conductor layer uses an anodic oxidation method. (3) The method for manufacturing a drive circuit board according to claim 2, wherein Ta is used as the first conductor layer. (4) The first conductor layer has a thickness of 1000 Å to 3000 Å.
Claim 2, characterized in that Ta of Å is used.
A method for manufacturing a drive circuit board as described in 2.