JP2001142093A - Active matrix substrate for liquid crystal display device and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify a method for manufacturing an active matrix substrate for a liquid crystal display device using reverse staggered thin-film transistors(TFTs). SOLUTION: Gate electrodes 19, common electrodes 13, gate bus wiring and common bus wiring 24 of the active matrix substrate for the cross electric field type liquid crystal display device using the reverse staggered TFTs are composed of Al films or first Al alloy films and source-drain electrodes 17 and 18 and drain bus wiring 25 are composed of single layer films of second Al alloy films. The lower layers as the gate terminals and drain terminals are composed of the Al films or the first Al alloy films and the upper layers are composed the multilayer film of the second Al alloy films. The ground surface is subjected to high-frequency sputter etching when the second Al alloy films are formed, by which the contact resistance of the source-drain electrodes and (n) type semiconductor layers 15, etc., is lowered.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an active matrix substrate for a liquid crystal device and a method for manufacturing the same, and more particularly to an active matrix substrate suitable for a lateral electric field type (hereinafter referred to as an IPS type) liquid crystal display device and a reflection type liquid crystal display device. And its manufacturing method.

[0002]

2. Description of the Related Art In recent years, as the size of liquid crystal display devices has increased, gate bus lines formed using a metal material having a relatively high electric resistance such as chromium (Cr), molybdenum (Mo), and tantalum (Ta). The delay of the signal on the drain bus wiring is a serious problem. Therefore, as a wiring material, pure aluminum (Al) having a low specific resistance or an alloy thereof has been widely used.

An IPS type liquid crystal display device using an Al alloy for the gate, drain, common wiring, and electrode is disclosed in, for example, Japanese Patent Application Laid-Open No.
Of the prior art). This conventional T
FIG. 11 shows a cross-sectional structural view of the FT, and FIG. 12 shows a plan view and a cross-sectional view of the gate terminal.

Referring to the sectional view of the TFT shown in FIG. 11, a gate electrode 89 is formed on a transparent glass substrate 11 by coating an anodic oxide film 94 on an Al alloy film 91, and further covers a gate insulating film 82. After that, the non-doped semiconductor layer 84 and the n-type semiconductor layer 85 are patterned.
Furthermore, the n-type semiconductor layer 85, the connecting Cr film 93 and the Al
After the drain electrode 88 and the source electrode 87 made of a multilayer film of the alloy film 92 are patterned, the protective film 90 is covered to form a TFT portion.

Japanese Patent Application Laid-Open No. 11-2840 discloses that
The wiring structure of the drain bus wiring is a multilayer structure of a lower Cr film and an upper Al alloy film. For connection with the ITO film of the external connection conductive film, the lower Cr film is exposed, and the ITO film and the Cr film are exposed.
Techniques for connecting membranes are disclosed.

In FIG. 12, Al is placed on a transparent glass substrate 11.
After depositing and patterning the alloy film 91, an ITO film 96 for connection to an external drive circuit is deposited and patterned on the Al alloy film 91, and a chromium film (Cr film) 93 and an Al alloy film 92 are sequentially deposited. And patterned to form a gate terminal. Cr film 93 is ITO film 9
1 and the Al alloy film 94. The electrical connection between the Al alloy film 94 and the ITO film 91 via the Cr film 93 as described above is because an Al oxide film is formed between the ITO film 91 and the Al alloy film 94. This is because the contact property is easily reduced.

[0007]

In the first prior art, the Al alloy film is used for the gate wiring, the source / drain electrodes, etc., but the connection between the n-type semiconductor layer of the TFT and the Al alloy film. The connection between the ITO film for external connection of the gate terminal and the drain terminal and the Al alloy film is made by interposing a high melting point metal such as a Cr film, so that complicated processes such as a combination of wet etching and dry etching are performed. Is required, which causes an increase in the active matrix substrate manufacturing cost. Furthermore, since the total thickness of the wirings and electrodes is increased by the amount of the upper layer metal, the margin of the rubbing condition for properly maintaining the alignment of the liquid crystal is narrowed. There are problems that are likely to occur.

An inverted stagger type TFT array substrate for the purpose of reducing the manufacturing cost of the prior art is disclosed in
No. 319431 (hereinafter referred to as a second prior art). In this technique, a high melting point metal such as Cr, Mo, Ta, or W is used for the source / drain wiring and the gate electrode, and a single-layer film such as Al—Si—Cu or Al—Mo is used for the source / drain electrode and the gate wiring. Is used.

In the second prior art, since a high-resistance metal material is used for the source / drain wiring and the gate electrode, the electrical resistance of these wirings and electrodes is high, and the source / drain electrode and the n-type There is a problem that the contact resistance between the semiconductor layer and the source / drain electrode is increased.

Another technique which improves the first prior art is disclosed in Japanese Patent Application Laid-Open No. Hei 10-284493 (hereinafter referred to as a third prior art). In the present technology, one or more rare earth elements and Ti, Ta, Mo, C
A single layer film of an alloy film (for example, Al—Nd—Ti) of one or more of r, Au, Ag, and Cu and Al is used for the gate electrode, the so-so drain electrode, and the wiring.

However, in the third prior art, since a single-layer film of an Al alloy film is used for the gate electrode, the source / drain electrode and the wiring, the process of forming these electrodes and wiring can be simplified. However, there is a problem that the contact resistance between the source / drain electrodes and the contact layer (n-type semiconductor layer) tends to increase.

The above-described second and third prior arts do not disclose a wiring structure of an external connection terminal.

An object of the present invention is to provide an active matrix substrate suitable for an IPS type liquid crystal display device and a reflection type liquid crystal display device which solves the above-mentioned problems of the prior art, and a method of manufacturing the same.

[0014]

According to a first aspect of the present invention, there is provided:
In an active matrix substrate for an in-plane switching type liquid crystal display device using an inverted staggered thin film transistor, a gate electrode, a common electrode, a gate bus wiring, and a common bus wiring are connected to A
1 film or a first Al alloy film, a source electrode, a drain electrode, and a drain bus wiring are formed as a second Al alloy film, and a gate terminal and a drain terminal for connection to an external drive circuit are formed under the Al film or the first film. The first Al alloy film is characterized in that the upper layer is composed of a multilayer film of the second Al alloy film.

The first Al alloy film contains Al as a main component and a lanthanoid element, Si, Cu, A
one or two selected from u, Ag, Ti, Ta
The second Al alloy film may be an alloy of Al and Si or Al and Si and a lanthanoid element, Cu, A
one or two selected from u, Ag, Ti, Ta
An Al alloy to which more than one kind is added can be used. By including Si in the second Al alloy film, diffusion of Al into the thin film transistor can be prevented.

According to a second structure of the present invention, in an active matrix substrate for a reflection type liquid crystal display device using an inverted staggered thin film transistor, a gate electrode and a gate bus wiring are formed of an Al film or a first Al alloy film. The source electrode, the drain electrode, the drain bus line, and the projection below the pixel electrode on the gate insulating film are formed of a second Al alloy film, and the pixel electrode is formed of a third Al alloy film. The gate terminal has a lower layer formed of the Al film or the first Al alloy film, and an upper layer formed of a multilayer film of the third Al alloy film. A drain terminal for connecting an external drive circuit has a lower layer formed of the third Al alloy film. It is characterized in that it is constituted by the second Al alloy film and the upper layer is constituted by a multilayer film of the third Al alloy film.

In the above active matrix substrate for a liquid crystal display device according to the second configuration of the present invention, the first Al
As the alloy film and the second Al alloy film, the same films as the Al alloy film in the first configuration of the present invention can be used.

Further, as the third Al alloy film, A
l as the main component, and lanthanoid elements, Si, C
An Al alloy to which one or more selected from u, Au, Ag, Ti, and Ta are added can be used.

In the manufacture of the active matrix substrate for a liquid crystal display device according to the first aspect of the present invention, the surface of the thin film transistor and the gate terminal and the drain terminal on which the second Al alloy film is formed is previously set in a vacuum device. After high-frequency sputter etching, the second Al alloy film (source / drain electrode) of the thin film transistor and the underlying semiconductor layer and the second Al alloy film are formed without breaking vacuum in the vacuum device. The contact resistance of the gate and drain terminals of the second Al alloy film can be reduced, and the reliability of the active matrix substrate can be improved.

In the manufacture of the active matrix substrate for a liquid crystal display device according to the second configuration of the present invention,
The second Al alloy film forming surface of the thin film transistor,
The third A of the gate terminal and the drain terminal
After high-frequency sputter etching of the l-alloy film forming surface in a vacuum device in advance, the second Al alloy film and the third Al alloy film are formed in the vacuum device without breaking vacuum, The second Al alloy film and the third A
The contact resistance between the alloy layer and the base can be reduced, and the reliability of the active matrix substrate can be improved.

[0021]

Next, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a first embodiment of the invention.
FIG. 4 is a circuit conceptual diagram of the active matrix substrate according to the embodiment of the present invention, which is applied to an IPS liquid crystal display device.

In FIG. 1, the active matrix substrate has a gate bus line 23, a common bus line 24, and a drain bus line 25 arranged in a matrix on a transparent glass substrate 11, and the gate bus line 23 and the drain bus line 2
5, near the intersection of the gate electrode 19, the source electrode 17,
It has a structure in which a thin film transistor (hereinafter abbreviated as TFT) composed of the drain electrode 18 is arranged. In FIG. 1, reference numeral 16 denotes a liquid crystal, and reference numerals 31, 3
2 is a gate terminal and a drain terminal, respectively, which are used for external connection.

FIG. 2A is a plan view of one pixel portion of the active matrix substrate of FIG. 1, and FIG. 2B is a plan view of FIG.
It is AA 'sectional drawing of (a). A gate electrode 19 made of an Al film or a first Al alloy film is selectively formed on the surface of the transparent glass substrate 11, and faces the gate electrode 19 via the gate insulating film 12 above the gate electrode 19. A non-doped semiconductor layer 14 made of island-shaped amorphous silicon or the like and an n-type semiconductor layer 15 made of amorphous silicon or the like, and a pair of second A connected to the non-doped semiconductor layer 14 via the n-type semiconductor layer 15 respectively.
A source electrode 17 and a drain electrode 18 made of an 1 alloy film are formed to form an inverted staggered TFT. Further, a gate bus wiring 23 and a common bus wiring 24 made of an Al film or a first Al alloy film selectively formed on the surface of the transparent glass substrate 11, and a gate bus wiring 23 and a common bus wiring 24 via the gate insulating film 12. An active matrix substrate is formed by arranging a drain bus line 25 and a source electrode 17 made of a second Al alloy film and intersecting with the drain electrode 18 in a matrix as shown in FIG. In FIG. 1, reference numerals 31 and 32 denote a gate terminal and a drain terminal for connection to an external drive circuit, respectively. When an Al film is used for the gate electrode or the like, an anodic oxide film is formed on the surface to prevent hillocks.

The first Al alloy film contains Al as a main component and a lanthanoid element, Si, Cu, A
An Al alloy added with one or more of u, Ag, Ti, and Ta can be used. La or Nd is suitable as a lanthanoid element.

As the second Al alloy film, Al—
Si alloy or Al with Si and lanthanoid element, Cu, A
An Al alloy film to which one or more of u, Ag, Ti, and Ta are added is used. The Si alloy containing Al is used as the second Al alloy film because the Al alloy to the n-type semiconductor layer (contact layer of the source / drain electrode) is used.
This is to prevent the diffusion reaction of.

FIG. 3A is a plan view of the gate terminal 31, and FIG. 3B is a sectional view taken along the line AA 'of FIG. 3A.
The gate terminal 31 is connected to the second Al film through the opening 33 in which the Al film or the first Al alloy film 41 drawn out as the end of the gate bus wiring 23 is provided in the gate insulating film 12.
It is connected to the alloy film 42 and has a structure in which an opening 35 is provided in the upper protective film 20 so as to be connected to an external drive circuit.

FIG. 4A is a plan view of the drain terminal 32, and FIG. 4B is a sectional view taken along the line AA 'of FIG. 4A. The drain terminal is connected to the second Al alloy film 42 drawn as an end of the drain bus wiring 25 and the Al film or the Al film previously provided in the lowermost layer through the openings 34 and 36 provided in the gate insulating film 12. It has a structure in which an opening 36 is provided in the upper protective film 20 by connecting the first Al alloy film 41 to the external drive circuit.

Next, a method of manufacturing the active matrix substrate according to the first embodiment of the present invention will be described with reference to FIG.

FIG. 5 is a cross-sectional view of the drain terminal portion, the TFT portion, and the gate terminal portion of the substrate shown in the order of steps for explaining the method of manufacturing the active matrix substrate according to the first embodiment of the present invention. The circuit conceptual diagram of the active matrix substrate is as shown in FIG. First, FIG.
, An Al—Nd—Si alloy target is formed on a transparent glass substrate 11 by sputtering using an Al—Nd—Si alloy target.
The first Al alloy film 41 made of d-Si is
A film is formed to a thickness of 00 nm.

Next, a gate electrode 19, a gate bus wiring 23, a comb-shaped common electrode 13, and a common bus wiring 24 (see FIG. 1) are formed by photolithography and etching.

Next, a gate insulating film 12 made of, for example, silicon nitride is coated to a thickness of about 400 nm by a plasma CVD method. Further, a non-doped semiconductor film made of amorphous silicon is covered by about 300 nm, and an n-type semiconductor film made of amorphous silicon is covered thereon by about 30 nm. Next, these semiconductor films are patterned by a photolithography method and an etching method, and a non-doped semiconductor layer 14 and an n-type semiconductor layer 15 are formed in an island shape (FIG. 5B), and then openings for gate and drain terminals are formed. The openings 33 and 34 are opened by etching (FIG. 5C).

Next, by performing high frequency sputter etching using an inert gas such as argon (Ar) in a sputtering apparatus, the Al--N exposed from the openings 33 and 34 is formed.
First Al alloy made of d-Si and n already exposed
After removing the surface native oxide film of the mold semiconductor layer 15, a second Al alloy film 42 of Al-Nd-Si is formed to a thickness of about 150 to 300 nm without breaking vacuum, and then photolithography and etching are performed. The source electrode 1
7, a drain electrode 18, and a drain bus wiring 25 (see FIG. 1) are formed.

After the completion of the high frequency sputter etching, the second
It is desirable that the time before the sputter deposition of the Al alloy film is as short as possible, for example, less than 1 minute. The reason is that although the inside of the sputtering apparatus is kept in a vacuum, a trace amount of oxygen or water is present, so that the surface of the n-type semiconductor layer 15 is oxidized again after a long time, and the oxide film becomes thick. It is to go. The sputtering apparatus used here is a multi-chamber type in which a high-frequency sputter etching chamber and a sputter deposition chamber are connected and maintained in a vacuum in a transfer chamber. 0.2-1W / c
m ² , gas pressure 0.5-1 Pa, processing time 0.5-
4 minutes. Under such conditions, a natural oxide film of about 5 to 30 nm is etched.

Next, the n-type semiconductor layer 15 exposed between the source and drain electrodes is removed by etching using the source and drain electrodes 17 and 18 as a mask (FIG. 5).
(D)).

Finally, the protective film 20 made of, for example, silicon nitride having a thickness of about 200 nm
After covering the entire substrate, the opening 3 for the gate and drain terminals
5 and 36 are opened by photolithography and etching to complete the active matrix substrate (FIG. 5).
(E)).

In the method of manufacturing the active matrix substrate according to the first embodiment, the protective film 20 is formed last. However, the step of forming the protective film 20 may be omitted.

Next, a second embodiment of the present invention will be described with reference to the drawings. FIG. 6 is a circuit conceptual diagram of an active matrix substrate according to a second embodiment of the present invention.
This is a case where the present invention is applied to a reflection type liquid crystal display device.

In FIG. 6, the active matrix substrate has a gate bus line 63 and a drain bus line 65 arranged in a matrix on a transparent glass substrate 11, and a gate electrode 59 near the intersection of the gate bus line 63 and the drain bus line 65. , A source electrode 57 and a drain electrode 58, and a thin film transistor (hereinafter abbreviated as TFT). In FIG. 1, reference numeral 56 denotes a liquid crystal, reference numeral 64 denotes a counter electrode, and reference numerals 71 and 72 denote a gate terminal and a drain terminal used for external connection.

FIG. 7A shows a thin film transistor (hereinafter referred to as TF).
7 (abbreviated as T).
FIG. 7B is a sectional view taken along the line AA ′ of FIG. TFT
Represents A selectively formed on the surface of the transparent glass substrate 11.
a non-doped semiconductor layer 54 made of island-shaped amorphous silicon or the like opposed to the gate electrode 59 via the gate electrode 59 made of the l film or the first Al alloy film and the gate insulating film 52, and an n-type semiconductor layer 55 It is an inverted staggered type having a pair of source and drain electrodes 57 and 58 made of a second Al alloy film connected to the non-doped semiconductor layer 54, respectively.

The pixel electrode 62 made of a third Al alloy film connected to the source electrode 57 through the opening 61
It is provided on an upper layer of the protrusion 66 made of the second Al alloy film as shown in FIGS. 7A and 7B, and has a structure having irregularities for the purpose of efficiently diffusing reflected light. Has become. Note that the projection 66 may be formed by any method as long as it is provided at least below the pixel electrode 62.

Further, a gate bus wiring 63 selectively formed on the surface of the transparent glass substrate 11 and a gate insulating film 52
Intersects with the gate bus line 63 through the drain electrode 58
Bus line 65 and source electrode 57 connected to
Are arranged in a matrix as shown in FIG. 6 to form an active matrix substrate.

As the first and second Al alloy films in FIG. 7, the same alloy films as in the first embodiment are used.
Further, the third Al alloy film mainly contains Al similar to the first Al alloy, and further includes a lanthanoid element, Si,
An Al alloy to which Cu, Au, Ag, Ti, Ta or the like is added is used.

FIG. 8A shows a gate terminal 71 (see FIG. 6).
8B is a sectional view taken along the line AA ′ of FIG. 8A. The gate terminal is an Al film or a first Al alloy film 41 drawn out as an end of the gate bus wiring 63.
And an uppermost third Al alloy 4 through an opening 73 provided so as to penetrate through the protective film 60 and the gate insulating film 52.
3 is connected to the external drive circuit.

FIG. 9A is a plan view of the drain terminal 72, and FIG. 9B is a sectional view taken along the line AA 'of FIG. 9A. The drain terminal is connected to the second Al alloy film 42 drawn out as an end of the drain bus wiring 65 and the uppermost third Al alloy 43 via an opening 74 provided in the protective film 60. This structure allows connection with an external drive circuit.

Next, a method of manufacturing an active matrix substrate according to a second embodiment of the present invention will be described with reference to FIG. FIG. 10 is a sectional view of a drain terminal portion, a TFT portion, and a gate terminal portion of a substrate shown in the order of steps for explaining a method of manufacturing an active matrix substrate according to a second embodiment of the present invention.

First, Al-Nd is placed on the transparent glass substrate 11.
The first Al alloy film 41 made of Al—Nd—Si is formed by a sputtering method using a
After forming a film of 50 to 300 nm, the gate electrode 59 and the gate bus wiring 6 are formed by photolithography and etching.
3 is formed (FIG. 10A).

Next, a gate insulating film 52 made of, for example, silicon nitride is coated to a thickness of about 400 nm by a plasma CVD method. Further, a non-doped semiconductor film made of amorphous silicon is about 300 nm, and an n-type semiconductor film is
After coating the semiconductor film, the semiconductor film is patterned into an island shape by a photolithography method and an etching method to form a non-doped semiconductor layer 54 and an n-type semiconductor layer 55 (FIG. 10B).

Next, by performing high-frequency sputter etching using a sputtering apparatus, the surface native oxide film of the n-type semiconductor layer 55 is removed, and then the Al-Nd
The second Al alloy film 42 made of Si
0 nm is formed. Thereafter, a source electrode 57, a drain electrode 58, a drain bus wiring 65, and a projection 66 made of a second Al alloy film are formed by photolithography and etching (FIG. 10C). Note that the projection 66 may be formed by any method as long as it is at least before the pixel electrode 62 is formed.

Further, after the n-type semiconductor layer 55 is removed by etching using the source and drain electrodes 57 and 88 as a mask, a protective film 60 made of, for example, silicon nitride is coated by a plasma CVD method to a thickness of about 200 nm. An opening 61 for connecting the electrode 57;
Openings 73 and 74 for the gate and drain terminals are formed by photolithography and etching (FIG. 10).
(D)).

Next, the first Al alloy film 41 and the second Al alloy film 42 exposed from the openings 61, 73 and 74 are subjected to high frequency sputter etching by a sputtering device.
After removing the surface natural oxide film, without breaking the vacuum,
The third Al alloy film 43 made of Al-Nd-Si is
A 50-300 nm film is formed, and then a third Al alloy film 43 is formed.
A pixel electrode 62 comprising a gate and drain terminals 71 and 7
2 is formed by photolithography and etching (FIG. 10E) to complete the active matrix substrate.

In the first and second embodiments, a channel-etch type TFT has been described. However, it is needless to say that the present invention can be applied to a channel protection type TFT.

In the present invention, as described in the method of manufacturing the active matrix substrate according to the first and second embodiments, the Al alloy film is formed on the n-type semiconductor layer and the lower layer film of the gate / drain terminal. It is characterized by having a high frequency sputter etching process before forming. By this treatment, the contact resistance of the n-type semiconductor layer, the lower layer film of the gate / drain terminal, and the Al alloy film formed on the surface thereof can be reduced.

FIG. 13 shows the result of examining the effect of high-frequency sputter etching on the contact resistance of the n-type semiconductor layer and the Al alloy film made of Al-Nd-Si formed thereon. As shown in FIG. 13, it was proved that the contact resistance was reduced by one to two digits when the high-frequency sputter etching was performed.

Similarly, FIG. 14 shows an example of a difference in TFT transistor characteristics depending on whether or not high-frequency sputter etching is performed. When the high-frequency sputter etching was not performed, a sufficient write current to drive the liquid crystal could not be obtained because of the high contact resistance between the Al—Nd—Si film and the n-type semiconductor layer. When high-frequency sputter etching was performed, the write current was improved by one digit or more, and favorable transistor characteristics were exhibited.

[0055]

As described above, according to the present invention, the following effects can be obtained. (1) Since the gate electrodes, source / drain electrodes, and other wirings of the active matrix substrate are formed of a single-layer film of an Al alloy, the number of photolithography steps can be reduced as compared with the related art, thereby manufacturing the active matrix substrate. Cost can be reduced and quality can be improved. (2) By using high-frequency sputter etching before forming the Al alloy film for the source / drain electrodes, it is possible to reduce the TFT contact resistance and improve the TFT characteristics. (3) An Al alloy film is used as the upper conductive film by subjecting the surface of the underlying Al alloy film to high-frequency sputter etching before the formation of the upper conductive film of the source / drain terminals, and is formed simultaneously with the wiring made of another Al alloy film. The manufacturing process can be simplified.

[Brief description of the drawings]

FIG. 1 is a circuit conceptual diagram of an active matrix substrate when applied to an IPS type liquid crystal display device according to a first embodiment of the present invention.

FIG. 2 is a plan view and a cross-sectional view of one pixel portion of the active matrix substrate of FIG.

3A and 3B are a plan view and a cross-sectional view of a gate terminal unit in FIG.

4A and 4B are a plan view and a cross-sectional view of the drain terminal section shown in FIG.

FIG. 5 is a cross-sectional view of a drain terminal portion, a TFT portion, and a gate terminal portion of the substrate shown in the order of steps for explaining the method of manufacturing the active matrix substrate according to the first embodiment of the present invention.

FIG. 6 is a circuit conceptual diagram of an active matrix substrate when applied to a reflective liquid crystal display device according to a second embodiment of the present invention.

7A and 7B are a plan view and a cross-sectional view of one pixel portion including the thin film transistor unit of FIG.

8A and 8B are a plan view and a cross-sectional view of the gate terminal unit shown in FIG.

9A and 9B are a plan view and a cross-sectional view of the drain terminal section shown in FIG.

FIG. 10 is a cross-sectional view of a drain terminal portion, a TFT portion, and a gate terminal portion of a substrate shown in a process order for describing a method of manufacturing an active matrix substrate according to a second embodiment of the present invention.

FIG. 11 is a sectional structural view of a TFT of a first conventional active matrix substrate.

FIG. 12 is a plan view and a sectional view of a gate terminal of a first conventional active matrix substrate.

FIG. 13 is a graph showing the effect of high-frequency sputter etching on the contact resistance between an n-type semiconductor layer and an Al alloy film.

FIG. 14 is a graph showing the effect of high-frequency sputter etching on the drain current of a TFT transistor.

[Explanation of symbols]

Reference Signs List 11 transparent glass substrate 12, 52, 82 gate insulating film 13 common electrode 14, 54, 84 non-doped semiconductor layer 15, 55, 85 n-type semiconductor layer 16 liquid crystal 17, 57, 87 source electrode 18, 58, 88 drain electrode 19, 59, 89 Gate electrode 20, 60, 90 Protective film 23, 63 Gate bus wiring 24 Common bus wiring 25, 65 Drain bus wiring 31, 71 Gate terminal 32, 72 Drain terminal 33, 34, 35, 36, 61, 73, 74 , 95
Opening 41 Al film or first Al alloy film 42 Second Al alloy film 43 Third Al alloy film 56 Liquid crystal 62 Pixel electrode 64 Counter electrode 66 Projection 91, 92 Al alloy film 93 Cr film 94 Anodized film 96 ITO film

 ──────────────────────────────────────────────────続 き Continued from the front page F term (reference) 2H092 GA42 JA26 JA40 JA44 JA47 JB07 JB24 JB33 KA05 KA10 KA18 KB04 MA05 MA13 MA18 NA18 NA27 NA28 NA29 PA01 PA12 5C094 AA12 AA24 AA31 AA43 AA44 AA48 AA53 BA03 DB01 DB02 EA05 EA06 EA07 EB02 EB04 FA01 FA02 FB12 FB14 FB15 GB10 5F033 GG04 HH09 HH10 JJ09 JJ10 KK08 KK09 KK10 MM05 QQ09 QQ14 QQ37 QQ92 QQ94 RR06 SS15 VV07 VV15 XX09 FF33 XXA XX33 XXA XX33 XXA HL23 HL26 NN01 NN24 NN35

Claims (9)

[Claims] 1. An inverted staggered thin film transistor,
In an active matrix substrate for a horizontal electric field type liquid crystal display device, a gate electrode, a common electrode, a gate bus wiring, a common bus wiring is an Al film or a first Al alloy film, and a source electrode, a drain electrode, and a drain bus wiring are a second Al
The gate terminal and the drain terminal for connection to an external drive circuit are made of an alloy film, the lower layer of which is the Al film or the first A film.
An active matrix substrate for a liquid crystal display device, wherein an upper layer of an l-alloy film is constituted by a multilayer film of the second Al alloy film. 2. The method according to claim 1, wherein the first Al alloy film contains Al as a main component and a lanthanoid element, Si, Cu, Au, A
2. The active matrix substrate for a liquid crystal display device according to claim 1, wherein the active matrix substrate is made of an Al alloy to which one or more selected from g, Ti, and Ta are added. 3. The method according to claim 1, wherein the second Al alloy film is made of an alloy of Al and Si or Al and Si and a lanthanoid element, Cu, A
one or two selected from u, Ag, Ti, Ta
3. The active matrix substrate for a liquid crystal display device according to claim 1, wherein the active matrix substrate is made of an Al alloy to which at least one kind is added. 4. An inverted staggered thin film transistor,
In an active matrix substrate for a reflection type liquid crystal display device, the gate electrode and the gate bus wiring are formed of an Al film or
The source electrode, the drain electrode, the drain bus wiring, and the pixel electrode lower protrusion on the gate insulating film are formed of the second Al alloy film, and the pixel electrode is formed of the third Al alloy film.
The gate terminal for external drive circuit connection has a lower layer formed of the Al film or the first Al alloy film and an upper layer formed of a multilayer film of the third Al alloy film. A liquid crystal display characterized in that a drain terminal for connecting an external drive circuit has a lower layer formed of the second Al alloy film and an upper layer formed of a multilayer film of the third Al alloy film. Active matrix substrate for equipment. 5. A method according to claim 1, wherein the first Al alloy film contains Al as a main component and a lanthanoid element, Si, Cu, Au, A
5. The active matrix substrate for a liquid crystal display device according to claim 4, wherein the active matrix substrate is made of an Al alloy to which one or more selected from g, Ti, and Ta are added. 6. The second Al alloy film is made of an alloy of Al and Si or Al and Si and a lanthanoid element, Cu, A
one or two selected from u, Ag, Ti, Ta
6. The active matrix substrate for a liquid crystal display device according to claim 4, wherein the active matrix substrate is made of an Al alloy to which at least one kind is added. 7. The third Al alloy film contains Al as a main component and a lanthanoid element, Si, Cu, Au, A
7. The active matrix substrate for a liquid crystal display device according to claim 4, wherein the active matrix substrate is made of an Al alloy to which one or more selected from g, Ti, and Ta are added. 8. The method of manufacturing an active matrix substrate for a liquid crystal display device according to claim 1, wherein said thin film transistor and said gate terminal and drain terminal on which said second Al alloy film is to be formed have a vacuum. A method for manufacturing an active matrix substrate for a liquid crystal display device, comprising a step of forming the second Al alloy film without breaking vacuum in the vacuum device after high-frequency sputter etching in the device. 9. The method for manufacturing an active matrix substrate for a liquid crystal display device according to claim 4, wherein said second Al alloy film forming surface of said thin film transistor, said gate terminal and said drain terminal are provided. Third
Forming the second Al alloy film and the third Al alloy film without breaking the vacuum in the vacuum device after the high frequency sputter etching of the Al alloy film forming surface in advance in the vacuum device. A method for manufacturing an active matrix substrate for a liquid crystal display device, comprising: