JPS6147982A - Drive circuit substrate for display unit and manufacture thereof - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a structure of a drive circuit board for a liquid crystal display device, etc., including a thin film transistor layer and a multilayer wiring structure, and a method for manufacturing the same.

[Technical background of the invention and its problems]

Electroluminescence, light emitting diode.

Display devices such as plasma, fluorescent display tubes, and liquid crystal display devices can have thinner display parts, and are in increasing demand for use in terminal display devices such as measuring instruments, office equipment, and computers, or special display devices. . Among these, electroluminescence and liquid crystal display devices that use switching element matrix arrays of thin film transistors are attracting attention as display devices and have been developed in various places in recent years because they can reduce power consumption and cost. (For example, I
EEETransactions on Electr
on Devices, Vol ED-20°No,
IL November 1971. PP995-10
01).

FIG. 9 is a circuit diagram of a display panel using a general thin film transistor array. 40 (40+, 4
02, . . . 40°) are address lines that commonly drive the gate electrodes of the thin film transistors 41 arranged in the lateral force direction, and 42 (428, 42□, . . . 42 u) are the source electrodes of the thin film transistors 41 arranged in the vertical direction. ; is a data line that provides a dihedral image signal. A thin film transistor 41 is used for each pixel corresponding to each intersection of an address line 40 and a data line 42, and each drain electrode is connected to a display element 43.
Both are also connected to a capacitor 44. The display element 43 is, for example, a liquid crystal or an electroluminescent element. Taking a liquid crystal display panel as an example, address lines 40. data line string.

It is constructed by sandwiching a liquid crystal layer between a drive circuit board on which a transistor 41 and a capacitor are integrated, and a substrate opposing the drive circuit board on which two transparent electrodes are formed on the entire surface. The thin film transistor used here has recently become 0N.
- The OFF characteristics have been improved, and even without a capacitor serving as an auxiliary capacitance, it has become possible to maintain the written image information for a sufficiently long time using only the capacitance of the liquid crystal itself, which serves as the display element 43. If such a display panel is driven in a line-sequential manner in which data is written for each address line, the display element 43 can be driven at a duty ratio of about 100 inches, so that an easy-to-see image can be obtained.

Ru.

By the way, Si in a crystalline, polycrystalline, or amorphous state can be used as a material for a switching transistor.

CdSe, Te, CdS, etc. are used. Among these, thin film technology for polycrystalline semiconductors and amorphous semiconductors is
Because low-temperature processes are possible, active matrix elements of switching transistors can be formed even on substrates that need to be handled at relatively low temperatures, such as glass substrates, making low-cost, large-area display devices practical. did.

However, in order to integrate active matrix elements including these switching transistors at high density and to obtain a large-area liquid crystal display device, sophisticated mask alignment technology is required. That is, when the area becomes large, the material or mask used tends to shrink, making it difficult to make the required transistor characteristics uniform.

[Purpose of the invention]

In view of the above-mentioned conventional problems, the present invention has been developed to eliminate the need for accurate mask alignment in the fine pattern part of a large-scale transistor matrix array, and to provide a display device that can uniformize the device characteristics of transistors. An object of the present invention is to provide a drive circuit board and a method for manufacturing the same.

[Summary of the invention]

That is, the present invention first includes a plurality of first metal wiring patterns forming gate electrodes formed on a transparent insulating substrate, and a plurality of first metal wiring patterns having the same width as the first metal wiring patterns on the first metal wiring patterns. A first insulating film pattern is formed on the first insulating film pattern, and a thin film semiconductor having the same width as the first extra-length wiring pattern and the first insulating film pattern and a predetermined length is formed on the first insulating film pattern. Multiple patterns are formed.

A transparent conductive film pattern is formed from each of the thin film semiconductor patterns and is in contact with the end surfaces and side surfaces thereof. This transparent conductive pattern is perpendicular to the first metal wiring pattern and has the same width as the length of the thin film semi-conductor pattern, and the short strip pattern is centered on the thin film semiconductor pattern (separated left and right). are formed to form source and drain electrodes.This transparent conductive film, pattern and H,
A second insulating film pattern covering the in-film conductor pattern and the first insulating film pattern is formed to have the same width as the first insulating film. Then, on the second insulating film on which the transparent conductive film pattern and the thin film semiconductor pattern are not formed, a plurality of second metal wiring patterns are formed, which are perpendicular to the first metal wiring pattern and become data lines. Each of the second main wiring patterns extends to each of the source electrodes of the transparent conductive film pattern at a predetermined location, thereby making an electrical connection.

On the other hand, a third metal pattern electrically isolated from the second metal wiring pattern is formed on a second insulating film pattern located on a part of the transparent conductive film pattern and the thin film semiconductor pattern. There is.

〔Effect of the invention〕

According to the present invention, the gate electrode pattern, the gate insulating film pattern, and the thin film semiconductor pattern that will become the active layer are processed using the same mask, and the overlapping portions of the source and drain electrodes are formed on the thin film semiconductor film pattern and external light is used. The mask stand and beam used to form the second insulating film pattern for forming optical shield nozzles to eliminate leakage current from switching transistors uses self-line exposure from the back of the substrate, so there is no need for a mask stand. The total number of masks in the process of forming a switching transistor matrix layer can be greatly reduced compared to conventional manufacturing methods.

Wear.

In addition, the formation of the first metal wiring for the gate electrode] (the metal film as a turn, the gate insulation theory, and the thin film semiconductor layer) is coupled It is possible to eliminate defects that occur during the process of forming each film, especially pinholes in the gate insulating film.Furthermore, it is possible to eliminate defects that occur in the processing steps of each film formation process, especially pinholes in the gate insulating film.

Transparent conductive B becomes the drain electrode! The position of the second wiring nozzle, which will become the A/couple and data line electrodes, needs only to be perpendicular to the gate electrode, and even if the substrate material shrinks or expands during the process, fine mask alignment can be achieved. On the other hand, since the insulating film at the intersection of the gate electrode wiring and the data electrode has a two-layer groove structure (the Ugate electrode and the source and drain electrodes Since the parasitic capacitance can be reduced, it is possible not only to reduce the loss of the data signal in data writing but also to improve the writing speed.

[Embodiments of the invention]

Examples of the present invention are shown below in Figure 1 (a), (ω, (c), Figure 2 (a), (b), (c), '?A 8
Figures (a), (b), (c), $4Figure (a),
(b).

Figure 5 (a), (b), (c), $ Figure 6 (a)
, (b).

First, as shown in Figure 2, on a transparent insulating substrate (21) made of a glass substrate with a thickness of about 2 mm (-2 mm), an aluminum film of N (2 layers) is deposited by vacuum evaporation or sputtering, and then about S 1o2 of low temperature sensitive membrane at 2000
(c) was soaked and pressed using the CVD method, and then approximately 2000i a-
8iiQ4) and about 800% na-8i film (c) are successively grown in a vapor phase.

Then, a positive type photoresist (126) was applied to the entire surface of the substrate on which these films were deposited to form a predetermined pattern, and n''a-8i BfAIJe, a-8i
PjAQ4J,, 5iOzlli%123.

Aluminum Jia (2) was patterned by etching one after another, and the exposed parts on the side surfaces of the aluminum G and @ patterns were oxidized using the aluminum anodic oxidation method while leaving the photoresist (C), to form a side insulating film (fabric). ). During this anodic oxidation, an aluminum MC2' is formed in order to make an anodizing electrode extraction terminal (22e) on a part of the common electrode (22d) for anodizing provided around the insulating substrate (21). Before etching step 4, a photoresist of the same type is formed.Furthermore, after the anodization is completed, this photoresist is reprocessed by exposing it to light using a thick mask that hides the internal pattern and allows light to shine only around the substrate. Then n again
10a-8i membrane (c) 18-slm (foundation).

The SiOx film (c) is etched to form a terminal part (22b) of an aluminum film (manufactured by Co., Ltd.) that will become a gate electrode, an electrode extraction line for anodic oxidation (22c), and a common line (2).
2d) Expose. After removing this eye and the photoresist □□□, Figure 2 (a) and its cross-sectional view Figure 2 (b) and (
The structure shown in C) is obtained.

Next, a transparent conductive film (c) made of, for example, ITO (indicum, tin, oxide) is deposited to a thickness of about 5,000 sq. by vacuum evaporation or sputtering. After that, apply a positive type E)l/Jisu)+21 to the entire surface of the substrate, for example, set @Y to 200ttmr, set the length , (22a), StO,
llG4123).

a-' A cyst pattern Ql is formed, which is arranged perpendicularly to the Si film, etc., and whose left-right ratio SST to the underlying pattern of length X is about 228. The transparent conductive film (c) in the area removed by photoresist development ζ2, the n"a-8i film (c),
The a-8f film ■ is continuously etched to produce the results shown in Fig. 8(a).
(b).

Obtain the structure (c).

Next, remove the photoresist @, apply a new negative type photoresist (1) to the entire surface of the substrate, and apply it to the insulating substrate (21).
Exposure is performed by shining light from the back of the photoresist.
It is formed on the a-8i film so that it overlaps by about 1 μm from both sides. Then, by this development, the transparent conductive film (to) in the part where the photoresist (to) was removed and f! +a-8
Im (c) is etched to form a source side electrode (23a) and a drain side electrode (28b) of the transparent conductive film to obtain the structure shown in FIGS. 4(a) and 4(b).

Next, remove the negative type (Ho) L/cyst (to) and replace the insulating film t31) made of a low temperature iron film such as Si02 with carbon.
Approximately 2000λ product is estimated using the VD method. Next, a positive type photoresist is applied to the entire surface of the pulp plate and exposed to light from the back to form an aluminum MA (22a) with a base pattern.

(22b), (22c), (22d), (22e
) is formed, and this photoresist (insulating MC31) is etched. After this, the rough mask used in the previous step is used again to coat the positive type photoresist on the gate electrode terminal area (22b) around the substrate (including the anodizing electrodes (22c), (22d), and (22e)). Reprocessed to 5iOt
) J51. Perform etching of f31J.

If all of this positive type photoresist is removed, the structures shown in FIGS. 5(a), (b), and (c) are obtained.

Next, apply a metal film such as aluminum to a thickness of about 1 inch over the entire surface of the substrate.
After depositing .mu.m, a positive type photoresist is applied, a mask is aligned, and the metal mr3z is etched. This nua includes a data line (32a) with a width of about 80 μm, a source electrode (32b), a data line electrode terminal part (2c), a light shield pattern (82d) on the channel part, and a gate fin electrode. terminal for (
82e) is formed at the same time as shown in FIG. 1(a).

The structures of (b) and (c) are obtained. This: From the second step, the substrate that constitutes the manorix array part of the thin film transistor can be completed, and after this, the substrate on the side opposite to this substrate:
A liquid crystal display device can be obtained by forming two transparent conductive films and injecting two liquid crystals into the gap between the two substrates, but at this time, the metal film such as aluminum is prevented from reacting with the liquid crystal and becoming defective. A protective film Q made of polyimide resin, etc. is applied to protect the
), (b).

In the above embodiments, Nialuminum was used as the metal film of the wiring serving as the gate electrode, but a metal such as Ta which is easily anodized may also be used.

Saraji is not limited to the anodization method, but when using a metal such as aluminum, an alumite processing method by boiling may be used. In this case, a common electrode for anodic oxidation and its extraction terminal for oxidizing the side surface of the gate electrode are unnecessary. Furthermore, the gate insulating film used in this example is SiO
In addition to □, the same can be made using insulating films such as Si3N4M deposited by low-temperature CVD method or Ta, 205, S+02 deposited by sputtering method.

Furthermore, the metal film used as the data line is not limited to aluminum, but may also be Cr, Aluminum, Co, Ti, Mo, or a combination of these metals.

Next, FIGS. 7 and 8 (showing a modification of the present invention).

That is, as shown in FIG. 7, a transparent conductive film (
After forming the patterns 28a) and (28b), a source electrode (8) extending from the second electrode pattern (32a) is formed.
2b) to form an electrical l: contact. In addition, as shown in Fig. 8), transparent conductive film patterns (2sa) and (2s
If b) is formed, the second gold 5 pattern (32a)
There is no need to provide a convex source electrode (azb) as shown in FIG.

In short, the present invention provides a large-area matrix by combining a self-alignable structure, materials, and manufacturing method for forming source electrodes, drain electrodes, and electrodes provided at both ends of a thin-film semiconductor film pattern serving as a channel region. In addition to using a method that completely eliminates variations in the characteristics of each transistor caused by subtle positional misalignment of masks in the array, the structure and manufacturing method can eliminate a series of processes involved in manufacturing liquid crystal display devices. Demeru.

[Brief explanation of the drawing]

1 to 8 are diagrams showing embodiments of the present invention, and FIG. 9 is a diagram showing a conventional example. 21... Insulating substrates 22, 22a, 22b, 22c, 22d, 22
e...first gold, am23...first insulating layer
24...a-8i [25-n+a-8t M
26, 29, 30”・Photoresist 2
7... Side insulating film A + 28a, 28b... Transparent conductive film 31... Second insulating film 32, 82a, 32b, 32c, 32d, a
2e -'Jr 2's metal film 33...Protection theory agent Patent attorney Noriyuki Chika (and 1 other person) Fig. 1 An' Fig. 2 Pain' Fig. 3 Each' Fig. 4 4ρ Fig. 5 4θ Figure 6

Claims (2)

[Claims] (1) A first metal wiring pattern forming a plurality of gate electrodes formed on a transparent insulating substrate, and a gate formed on the first metal wiring pattern and having the same width as the first metal wiring pattern. a first insulating film pattern serving as an insulating film; and a transistor channel formed on the first insulating film pattern and having a predetermined length and the same width as the first insulating film pattern and the first metal pattern. The first metal wiring pattern is in contact with a plurality of thin film semiconductor patterns serving as a region at the end surfaces and side surfaces of each of the thin film semiconductor patterns, has a width equal to the length of the thin film semiconductor patterns, and is orthogonal to the first metal wiring pattern. a transparent conductive film pattern formed on an insulating substrate and serving as a source electrode and a drain electrode; and a first insulating film formed on a part of the transparent conductive film pattern, the thin film semiconductor pattern, and the insulating film pattern. A second insulating film pattern formed to have the same width as the film pattern, and the first insulating film on the second insulating film on which the transparent conductive film pattern and the thin film semiconductor pattern are not formed, and on the insulating substrate. and a second metal wiring pattern forming a plurality of data lines formed so as to be orthogonal to the metal wiring and in contact with each of the source electrodes of the transparent conductive film pattern at a predetermined location. A drive circuit board for display devices featuring features. (2) A step of successively depositing a first metal wiring film, a first insulating film, and a thin film semiconductor film on one main surface of a transparent insulating substrate, and forming a plurality of thin films with a predetermined width by photoetching. a step of forming the same pattern of a first insulating film and a first metal wiring film; a step of converting the exposed side surface of the first metal wiring film into an insulator; and a step of forming the same pattern of the first insulating film and the first metal wiring film; a step of attaching a transparent conductive film to the surface of a transparent substrate, forming a pattern of the transparent conductive film in a direction perpendicular to the plurality of first metal wiring patterns by photoetching, and then removing the exposed portion of the thin film semiconductor film. The photoresist is exposed from the back side of the transparent insulating substrate so that the photoresist overlaps a part of the thin film semiconductor film, and the transparent conductive film and the thin film semiconductor film in the part where the photoresist is not present are removed. a step of removing a part of the surface, a step of attaching a second insulating film to the entire surface of the insulating substrate, and a step of exposing the photoresist from the back side to form the second insulating film in the same pattern as the first insulating film. a step of depositing a second metal wiring film on the entire surface of the substrate; and a step of forming a pattern of the second metal wiring film perpendicularly to the first wiring film pattern and partially etching the pattern by photoetching. A method for manufacturing a display device drive circuit board, comprising the step of forming a source electrode in contact with the transparent conductive film.