JP2005258115A - Thin film transistor type substrate, thin film transistor type liquid crystal display device, and method of manufacturing thin film transistor type substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thin film transistor type substrate provided with a transparent conductive film that hardly generates residues due to etching, a manufacturing method thereof, and a liquid crystal display device using the thin film transistor type substrate.
A transparent substrate, a source electrode provided on the transparent substrate, a drain electrode provided on the transparent substrate, and a transparent pixel electrode provided on the transparent substrate are provided. In the thin film transistor type substrate, the transparent pixel electrode contains indium oxide as a main component, and further contains one or more oxides selected from tungsten oxide, molybdenum oxide, nickel oxide, and niobium oxide. It is a conductive film, and the transparent pixel electrode is a thin film transistor type substrate electrically connected to the source electrode or the drain electrode, a manufacturing method thereof, and a liquid crystal display device using the thin film transistor type substrate.
[Selection] Figure 1

Description

  The present invention relates to a thin film transistor substrate for driving a liquid crystal of a liquid crystal display device. The present invention also relates to a method of manufacturing the thin film transistor substrate, and relates to a liquid crystal display device using the thin film transistor substrate.

Conventionally, liquid crystal display devices have been intensively researched and developed. In particular, in recent years, since the appearance of liquid crystal display devices for large-sized televisions, research and development has been made more actively.
In general, ITO (Indium Tin Oxide) is used as the material of the pixel electrode of the liquid crystal display device. This is because ITO is excellent in conductivity and transparency and can be easily etched by a strong acid (aqua regia, hydrochloric acid-based etchant).

  However, since ITO deposited on a large substrate by sputtering is a crystalline film, the crystal state changes variously depending on the substrate temperature, the atmosphere gas, and the plasma density, and the like. In some cases, a crystalline film and an amorphous film coexist. Due to this mixture, there has often been a problem that etching defects (conduction with adjacent electrodes, pixel electrode thinning due to over-etching, pixel defects due to etching residue, etc.) occur.

To solve the problems arising during etching, for example, Patent Document 1, by the ITO pixel electrode layer in an amorphous, _HCl-HNO 3 -H ₂ O system ITO / Al etching speed ratio to the etching solution of Is disclosed, and a method for improving the elution of Al generated during etching is disclosed.
In addition, the target made of ITO generates black particles (nodules) on the surface of the target during continuous film formation for a long time, which may cause abnormal discharge or cause foreign matters to cause pixel defects. It was often a problem.

  Therefore, when ITO is formed, amorphous ITO is formed by adding water or hydrogen to the sputtering gas, and after this ITO is etched, it is heated and crystallized. A method is being considered. However, when water or hydrogen is added at the time of film formation, the adhesion to the base substrate is often lowered, or the ITO surface is reduced and a large amount of nodules is often generated.

  In order to solve these problems, IZO (registered trademark: Idemitsu Kosan Co., Ltd., Indium Zinc Oxide) is used instead of the ITO. This IZO can form an almost complete amorphous film at the time of film formation, can be etched with a oxalic acid-based etchant which is a weak acid, can be etched with a mixed acid of phosphoric acid, acetic acid and nitric acid, an aqueous solution of ceric ammonium nitrate, etc. It is very useful. Also, this IZO can be etched with a weaker acid than ITO. Further, the target made of IZO is a useful target because it generates little nodules during sputtering and suppresses the generation of foreign matter.

As a target containing the above IZO, for example, in Patent Document 2 below, an oxide sintered body containing a hexagonal layered compound represented by the general formula In ₂ O ₃ (ZnO) _m (m = 2 to 20) is disclosed. A target is disclosed. According to this target, it becomes possible to form a transparent conductive film excellent in moisture resistance (durability).
As the transparent conductive film containing IZO, for example, in Patent Document 3 below, a coating solution prepared by dissolving an indium compound and a zinc compound in the presence of alkanolamine is applied to a substrate and baked. Thereafter, a method for producing a transparent conductive film by reducing treatment is disclosed. According to this method for producing a transparent conductive film, a transparent conductive film having excellent moisture resistance (durability) can be obtained.

As a method for etching the transparent conductive film containing IZO, for example, in Patent Document 4 below, a pixel electrode is formed by etching a transparent conductive film made of In ₂ O ₃ —ZnO with an aqueous oxalic acid solution. A method for manufacturing a liquid crystal display device is disclosed. According to this method of manufacturing a liquid crystal display device, etching is performed using an oxalic acid solution, so that a pattern of pixel electrodes can be easily formed. For this reason, a yield can be improved.

JP 63-184726 A JP-A-6-234565 Japanese Patent Laid-Open No. 6-187832 Japanese Patent Application Laid-Open No. 11-264995

However, ITO, which is generally used as a transparent pixel electrode material, has a problem that battery reaction is likely to occur when it is in contact with Al. In addition, crystalline ITO cannot be etched unless it is a strong acid such as aqua regia or hydrochloric acid, and there may be a problem that, for example, the wiring material of the TFT is corroded during the etching. On the other hand, in the case of amorphous ITO, the adhesiveness with the underlying substrate is often lowered, and the contact resistance with the TFT wiring material may be increased. In addition, a residue is generated during etching, which may cause a short circuit between the electrodes and a problem of liquid crystal driving.
In contrast, IZO has been devised as an amorphous material, but this material must produce a special hexagonal layered compound from indium oxide and zinc oxide, and the manufacturing process is The problem is that it is complicated and the cost is high.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a thin film transistor substrate including a transparent conductive film that hardly generates residues due to etching. Another object of the present invention is to provide a liquid crystal display device using the thin film transistor substrate. Still another object of the present invention is to provide a production method capable of efficiently obtaining the thin film transistor substrate.

  The above-mentioned object of the present invention is a transparent conductive material containing indium oxide as a main component as a transparent pixel electrode, and further containing one or more oxides selected from tungsten oxide, molybdenum oxide, nickel oxide, and niobium oxide. This is achieved by using a membrane. This transparent conductive film is formed in the shape of a transparent pixel electrode by patterning with an acidic etchant. Specifically, the present invention employs the following means.

  (1) First, the present invention provides a transparent substrate, a source electrode provided on the transparent substrate, a drain electrode provided on the transparent substrate, a transparent pixel electrode provided on the transparent substrate, In the thin film transistor substrate, the transparent pixel electrode contains indium oxide as a main component, and one or more oxides selected from tungsten oxide, molybdenum oxide, nickel oxide, and niobium oxide. A thin film transistor substrate, wherein the transparent pixel electrode is electrically connected to the source electrode or the drain electrode.

  In this patent, “comprising indium oxide as a main component” means that indium oxide is contained as a main component, and generally means that the atomic composition ratio is 50% or more. Further, when forming the transparent pixel electrode, a target composed of one or more oxides selected from tungsten oxide, molybdenum oxide, nickel oxide, and niobium oxide, which is mainly composed of indium oxide, is used. In this target, nodules are hardly generated.

  An amorphous transparent conductive film is formed by adding tungsten oxide, molybdenum oxide, nickel oxide, or niobium oxide to the transparent conductive film, and the formed amorphous transparent conductive film is then etched with oxalic acid. It is possible to perform etching using The film formation substrate temperature is R.I. T.A. It is preferable that it is (room temperature) -200 degreeC, More preferably, it is 80-180 degreeC. The reason why the substrate temperature at the time of film formation is within the above range is that, in order to control the substrate temperature to room temperature or lower, cooling is required and energy is lost. On the other hand, if the substrate temperature exceeds 200 ° C., the transparent conductive This is because etching with an etchant containing oxalic acid may not be possible due to crystallization of the film. In addition, water or hydrogen can be added to the atmospheric gas during film formation. Thereby, it becomes easy to etch the formed transparent conductive film using the etchant containing oxalic acid, and the residue can be further reduced.

In addition, the transparent conductive film on the substrate can be easily crystallized by etching the transparent conductive film formed by adding the metal oxide and then heating the temperature of the substrate to over 200 ° C. . The crystallization temperature is preferably 220 ° C., more preferably 230 ° C. or higher.
By crystallizing the transparent conductive film, the battery reaction is suppressed even when the transparent conductive film is in electrical connection with Al and in contact with the electrolyte. For this reason, etching defects such as disconnection of Al hardly occur.
The specific resistance of the transparent conductive film thus formed is reduced to the same extent as that of ITO. Moreover, this transparent conductive film is excellent in transparency.

The film thickness of a transparent conductive film becomes like this. Preferably it is 20-500 nm, More preferably, it is 30-300 nm, More preferably, it is 30-200 nm. If the film thickness of the transparent conductive film is less than 20 nm, the surface resistance of the transparent conductive film may increase. On the other hand, if the film thickness of the transparent conductive film exceeds 500 nm, the transmittance may decrease or the processing accuracy may be problematic. May occur.
The composition in the transparent conductive film has an In composition ratio (hereinafter sometimes referred to as an atomic ratio) as an atomic ratio, and a value of [In] / [all metals] is 0.85 to 0.99. It is preferable. When the In composition ratio is less than 0.85, the resistance value of the transparent conductive film may increase, or the transparent conductive film may not crystallize even if the substrate on which the transparent conductive film is formed is heated to 200 ° C. or higher. . If the In composition ratio exceeds 0.99, when the transparent conductive film is formed, the transparent conductive film is crystallized and cannot be etched with an etchant containing oxalic acid, or a large amount of residue is generated. Because there is. Here, [In] represents the number of indium atoms per unit volume in the transparent conductive film, and [All Metals] represents the number of all metal atoms per unit volume in the transparent conductive film.

Moreover, it is also preferable to add Sn and Zn as the third atom in the transparent conductive film. Note that the first atom is an indium atom in indium oxide, and the second atom is one or more kinds of oxides selected from tungsten oxide, niobium oxide, nickel oxide, and molybdenum oxide. A tungsten atom, a niobium atom, a nickel atom, and a molybdenum atom.
When adding Sn, the composition ratio of Sn as an atomic ratio is preferably [Sn] / [all metals] <0.2, and more preferably [Sn] / [all metals] <0. 1. If the value of [Sn] / [all metals] in the transparent conductive film is 0.2 or more, a residue may be generated during etching. Here, [Sn] represents the number of tin atoms per unit volume in the transparent conductive film.
When Zn is added, the composition ratio of Zn as an atomic ratio is preferably [Zn] / [all metals] <0.1, and more preferably [Zn] / [all metals] <0.1. 0.05. Here, [Zn] represents the number of zinc atoms per unit volume in the transparent conductive film.

  (2) Further, the present invention provides a transparent substrate, a source electrode provided on the transparent substrate, a drain electrode provided on the transparent substrate, a transparent pixel electrode provided on the transparent substrate, A thin film transistor comprising: a thin film transistor substrate comprising: a color filter substrate provided with a plurality of colored patterns; a thin film transistor substrate; and a liquid crystal layer sandwiched between the color filter substrates. Type transparent liquid crystal display device, wherein the transparent pixel electrode contains indium oxide as a main component and further contains one or more oxides selected from tungsten oxide, molybdenum oxide, nickel oxide, and niobium oxide. A thin film transistor, wherein the transparent pixel electrode is electrically connected to the source electrode or the drain electrode. It is a Njisuta type liquid crystal display device.

  In the thin film transistor type substrate, etching defects such as Al disconnection hardly occur in the manufacturing process. Therefore, if such a thin film transistor type substrate is used, a thin film transistor type liquid crystal display device with few display defects can be manufactured.

  (3) Further, the present invention provides a method of manufacturing the thin film transistor substrate according to (1) above, wherein the step of depositing the transparent conductive film on the transparent substrate and the depositing the transparent conductive film are acidified. And forming the transparent pixel electrode by etching using an etchant. The method of manufacturing a thin film transistor substrate, comprising:

The acidic etchant is preferably a weak acid. Even when the transparent conductive film is etched using an etchant of weak acid, almost no residue is generated by etching.
The oxalic acid concentration of the etchant containing oxalic acid is preferably 1 to 10 wt%, and more preferably 1 to 5 wt%. If the oxalic acid concentration is less than 1 wt%, the etching rate of the transparent conductive layer may be slow, and if it exceeds 10 wt%, oxalic acid crystals may be precipitated in an aqueous solution of an etchant containing oxalic acid.

  (4) Moreover, the present invention is characterized in that the acidic etchant contains one or more of oxalic acid, a mixed acid composed of phosphoric acid / acetic acid / nitric acid, and ceric ammonium nitrate (3) Is a method for producing a thin film transistor type substrate.

As described above, the transparent conductive film in the thin film transistor substrate of the present invention hardly generates residues due to etching using a weak acid (such as an organic acid) during production. For this reason, the thin film transistor substrate of the present invention is excellent in processability and yield is improved. Moreover, since the thin film transistor type liquid crystal display device of the present invention includes the thin film transistor type substrate, the manufacturing efficiency is improved.
In addition, according to the method for manufacturing a thin film transistor substrate of the present invention, a residue or the like due to etching of the transparent conductive film using a predetermined acidic etchant is hardly generated, so that the thin film transistor substrate can be efficiently manufactured. It becomes.

  Hereinafter, a preferred example of the present embodiment will be described with reference to the drawings.

  FIG. 1 shows a cross-sectional view of the vicinity of an α-Si TFT (amorphous silicon thin film transistor) active matrix substrate 100 in the first embodiment. Metal Al was deposited on the translucent glass substrate 1 by high frequency sputtering so that the film thickness became 1500 angstroms. The glass substrate 1 corresponds to an example of a transparent substrate described in the claims.

Next, the deposited metal Al is formed into the shape shown in FIG. 1 by a photoetching method using a phosphoric acid / acetic acid / nitric acid / water (volume ratio of 12: 6: 1: 1) aqueous solution as an etching solution. Etching was performed to form the gate electrode 2 and the gate electrode wiring 12.
Next, a silicon nitride film (hereinafter also referred to as a SiN film) that becomes the gate insulating film 3 is formed on the glass substrate 1, the gate electrode 2, and the gate electrode wiring 12 by glow discharge CVD. The film was deposited so that the film thickness was 3000 angstroms. Subsequently, an α-Si: H (i) film 4 is deposited on the gate insulating film 3 so as to have a film thickness of 3500 angstroms, and further, a silicon nitride film (SiN film) serving as the channel protective layer 5 ) Was deposited on the α-Si: H (i) film 4 so as to have a film thickness of 3000 Å.

At this time, the SiH ₄ —NH ₃ —N ₂ mixed gas is used as the discharge gas for the gate insulating film 3 and the channel protective layer 5 formed from the SiN film, while the α-Si: H (i) film is used. For No. ₄ , SiH ₄ —N ₂ mixed gas was used. Further, the channel protective layer 5 formed from this SiN film was etched by dry etching using a CHF-based gas to form the shape shown in FIG.
Subsequently, the α-Si: H (n) film 6 is formed on the α-Si: H (i) film 4 and the channel protective layer 5 by using a mixed gas of SiH ₄ —H ₂ —PH _3. The film was deposited so that the film thickness was 3000 angstroms.

  Next, on the deposited α-Si: H (n) film 6, a metal Mo / metal Al bilayer film is further formed. The film thickness of the lower metal Mo is 0.05 μm, and the film thickness of the metal Al is The layers were sequentially deposited by sputtering so as to have a thickness of 0.2 μm.

This metal Mo / metal Al bilayer film is shown in FIG. 1 by a photoetching method using a phosphoric acid / acetic acid / nitric acid / water (volume ratio is 9: 8: 1: 2) aqueous solution as an etching solution. Etching into a shape made the pattern of the drain electrode 7 and the pattern of the source electrode 8.
Furthermore, α-Si: H formed from the α-Si: H film by using dry etching using a CHF-based gas and wet etching using a hydrazine (NH ₂ NH ₂ .H ₂ O) aqueous solution in combination. (I) The film 4 and the α-Si: H (n) film 6 are etched to form a pattern of the α-Si: H (i) film 4 having the shape shown in FIG. 1 and the α-Si: H (n) film. The pattern was 6. Further, as shown in FIG. 1, a protective film was formed using a transparent resin resist 10, and a pattern such as a through hole was further formed.

Next, an amorphous transparent conductive film 9 mainly composed of indium oxide and tungsten oxide was deposited on the substrate subjected to the above treatment by a sputtering method. The target used for this sputtering method was In ₂ O ₃ − prepared so that the value of [In] / ([In] + [W]), which is the atomic ratio of In and W in the target, was 0.97. WO ₃ sintered body. Here, [In] represents the number of indium atoms per unit volume in the transparent conductive film 9, and [W] represents the number of tungsten atoms per unit volume in the transparent conductive film 9.

For the sputtering, this In ₂ O ₃ —WO ₃ sintered body was used by being placed on a planar magnetron type cathode, and a transparent conductive film 9 was deposited so that the film thickness became 1000 Å. At this time, pure argon gas or argon gas mixed with a trace amount of O ₂ gas of about 1 vol% was used as a discharge gas during sputtering.

The form in which the tungsten is contained in the target is in the form of tungsten oxide such as WO ₃ or WO ₂ and may be dispersed in the indium oxide sintered body, but indium oxide such as In ₂ W ₃ O _12. -It may be in the form of a complex oxide between tungsten oxides and dispersed in the indium oxide sintered body. Preferably, tungsten atoms are dispersed and dissolved in the indium sites of indium oxide, so that tungsten is dispersed at the atomic level in the indium oxide sintered body. Thus, it is more effective for tungsten to be dispersed in the indium oxide sintered body at the atomic level in order to obtain a transparent conductive film 9 with low discharge and stable discharge during sputtering.

The relative density of the target made of this In ₂ O ₃ —WO ₃ sintered body was 96%. In addition, according to another test, when the relative density of the target made of the In ₂ O ₃ —WO ₃ sintered body is 95% or more, it is confirmed that no nodules and abnormal discharge occur.
Moreover, when the transparent conductive film 9 which is the In ₂ O ₃ —WO ₃ film formed by the above sputtering was analyzed by the X-ray diffraction method, no peak was observed and it was found that the film was an amorphous film. Moreover, the specific resistance of the transparent conductive film 9 which is this In ₂ O ₃ —WO ₃ film is about 3.8 × 10 ⁻⁴ Ω · cm, and it was confirmed that the film can be used as a sufficient electrode. In addition, the specific resistance of the transparent conductive film 9 formed by adding 1 to 10 wt% of tin oxide to the target made of the In ₂ O ₃ —WO ₃ sintered body is 1.8 × 10 ^−4. It was also found that it was less than Ω · cm.

The transparent conductive film 9 which is this In ₂ O ₃ —WO ₃ film was etched by a photoetching method using an aqueous solution of 3.2 wt% oxalic acid as an etchant so as to form a pattern of a transmissive pixel electrode. As a result, a transmissive pixel electrode pattern made of an amorphous electrode of the transparent conductive film 9 shown in FIG. 1 was formed.
At this time, the pattern of the source electrode 8 and the pattern of the transparent pixel electrode made of the transparent conductive film 9 were formed in a desired pattern so as to be electrically connected. At this time, the drain electrode 7 and the source electrode 8 containing metal Al were not eluted with the etching solution. Next, this glass substrate 1 was heat-treated at 250 ° C. for 30 minutes. The aqueous solution of 3.2 wt% oxalic acid corresponds to an example of an acidic etchant containing oxalic acid described in the claims.

  Thereafter, a SiN passivation film (not shown) and a light shielding film pattern (not shown) were formed, and the α-Si TFT active matrix substrate 100 shown in FIG. 1 was manufactured. 1 is regularly formed on the glass substrate 1 of the α-Si TFT active matrix substrate 100. As shown in FIG. That is, the α-Si TFT active matrix substrate 100 of Example 1 is an array substrate. The α-Si TFT active matrix substrate 100 corresponds to a preferred example of the thin film transistor substrate described in the claims.

  A TFT-LCD type flat display was manufactured by providing a liquid crystal layer and a color filter substrate on the α-Si TFT active matrix substrate 100. This TFT-LCD type flat display corresponds to an example of a thin film transistor type liquid crystal display device described in claims. As a result of a dot inspection on the TFT-LCD type flat display, there was no defect of the pixel electrode, and a good display was obtained.

The α-Si TFT active matrix substrate 100 in Example 2 is substantially the same as FIG. 1 except for the composition of the transparent conductive film 9 of the α-Si TFT active matrix substrate 100 in Example 1 described above. Therefore, the α-Si TFT active matrix substrate 100 of Example 2 will also be described with reference to FIG.
As shown in FIG. 1, metal Al was deposited on a translucent glass substrate 1 by high frequency sputtering so that the film thickness was 1500 angstroms. Next, the deposited metal Al is formed into the shape shown in FIG. 1 by a photoetching method using a phosphoric acid / acetic acid / nitric acid / water (volume ratio of 12: 6: 1: 1) aqueous solution as an etching solution. Etching was performed to form the gate electrode 2 and the gate electrode wiring 12. The glass substrate 1 corresponds to an example of a transparent substrate described in the claims.

  Next, a silicon nitride film (hereinafter also referred to as a SiN film) that becomes the gate insulating film 3 is formed on the glass substrate 1, the gate electrode 2, and the gate electrode wiring 12 by glow discharge CVD. The film was deposited so that the film thickness was 3000 angstroms. Subsequently, an α-Si: H (i) film 4 is deposited on the gate insulating film 3 so as to have a film thickness of 3500 angstroms, and further, a silicon nitride film (SiN film) serving as the channel protective layer 5 ) Was deposited on the α-Si: H (i) film 4 so as to have a film thickness of 3000 Å.

At this time, the SiH ₄ —NH ₃ —N ₂ mixed gas is used as the discharge gas for the gate insulating film 3 and the channel protective layer 5 formed from the SiN film, while the α-Si: H (i) film is used. For No. ₄ , SiH ₄ —N ₂ mixed gas was used. The channel protective layer 5 formed from this SiN film was etched by dry etching using a CHF-based gas to form the shape shown in FIG.

Subsequently, the α-Si: H (n) film 6 is formed on the α-Si: H (i) film 4 and the channel protective layer 5 by using a mixed gas of SiH ₄ —H ₂ —PH _3. The film was deposited so that the film thickness was 3000 angstroms.
Next, on the deposited α-Si: H (n) film 6, a metal Mo / metal Al bilayer film is further formed. The film thickness of the lower metal Mo is 0.05 μm, and the film thickness of the metal Al is The layers were sequentially deposited by sputtering so as to have a thickness of 0.2 μm.
This metal Mo / metal Al bilayer film is shown in FIG. 1 by a photoetching method using a phosphoric acid / acetic acid / nitric acid / water (volume ratio is 9: 8: 1: 2) aqueous solution as an etching solution. Etching into a shape made the pattern of the drain electrode 7 and the pattern of the source electrode 8.

Furthermore, α-Si: H formed from the α-Si: H film by using dry etching using a CHF-based gas and wet etching using a hydrazine (NH ₂ NH ₂ .H ₂ O) aqueous solution in combination. (I) The film 4 and the α-Si: H (n) film 6 are etched to form a pattern of the α-Si: H (i) film 4 having the shape shown in FIG. 1 and the α-Si: H (n) film. The pattern was 6. Further, as shown in FIG. 1, a protective film was formed using a transparent resin resist 10, and a pattern such as a through hole was further formed.

Next, an amorphous transparent conductive film 9 mainly composed of indium oxide and molybdenum oxide was deposited on the substrate subjected to the above treatment by a sputtering method. The target used for this sputtering method was In ₂ O ₃ − prepared so that the value of [In] / ([In] + [Mo]), which is the atomic ratio of In to Mo in the target, was 0.90. This is a MoO ₃ sintered body. Here, [In] represents the number of indium atoms per unit volume in the transparent conductive film 9, and [Mo] represents the number of molybdenum atoms per unit volume in the transparent conductive film 9.

For the sputtering, this In ₂ O ₃ —MoO ₃ sintered body was used by being placed on a planar magnetron type cathode, and a transparent conductive film 9 was deposited so that the film thickness was 1000 angstroms. At this time, pure argon gas or argon gas mixed with a trace amount of O ₂ gas of about 1 vol% was used as a discharge gas during sputtering.
The form in which the molybdenum element is contained in the target may be a form of molybdenum oxide such as MoO ₃ or MoO ₂ and dispersed in the indium oxide sintered body. However, it may be in the form of a composite oxide of indium and molybdenum such as In ₂ Mo ₄ O ₆ , In ₂ Mo ₃ O ₁₂ or In ₁₁ Mo ₄ O ₆₂ and dispersed in the indium oxide sintered body. Preferably, molybdenum atoms are dispersed and dissolved in the indium sites of indium oxide, so that molybdenum is dispersed at the atomic level in the indium oxide crystal. Thus, it is more effective to obtain a transparent conductive film 9 having low resistance because molybdenum is dispersed in an indium oxide sintered body at an atomic level so that discharge is stable in sputtering.

The relative density of the target made of this In ₂ O ₃ —MoO ₃ sintered body was 96%. In addition, according to another test, when the relative density of the target made of the In ₂ O ₃ —MoO ₃ sintered body is 95% or more, it has been confirmed that no nodules and abnormal discharge occur.
Moreover, when the transparent conductive film 9 which is an In ₂ O ₃ —MoO ₃ film formed by the above sputtering was analyzed by an X-ray diffraction method, no peak was observed, and it was found to be an amorphous film. Moreover, the specific resistance of the transparent conductive film 9 which is this In ₂ O ₃ —MoO ₃ film is about 3.4 × 10 ⁻⁴ Ω · cm, and it was confirmed that the film can be used as a sufficient electrode. In addition, the specific resistance of the transparent conductive film 9 formed by adding 1 to 10 wt% of tin oxide to the target made of an In ₂ O ₃ —MoO ₃ sintered body is 1.9 × 10 ^−4. It was also found that it was less than Ω · cm.

The transparent conductive film 9 which is this In ₂ O ₃ —MoO ₃ film was etched by a photoetching method using an aqueous solution of 3.2 wt% oxalic acid as an etchant so as to form a transmissive pixel electrode pattern. As a result, a transmissive pixel electrode pattern made of an amorphous electrode of the transparent conductive film 9 shown in FIG. 1 was formed.
At this time, the pattern of the source electrode 8 and the pattern of the transparent pixel electrode made of the transparent conductive film 9 were formed in a desired pattern so as to be electrically connected. At this time, the metal Al drain electrode 7 and source electrode 8 were not eluted by the etching solution. Next, this glass substrate 1 was heat-treated at 250 ° C. for 30 minutes. The aqueous solution of 3.2 wt% oxalic acid corresponds to the acidic etchant containing oxalic acid described in the claims.

  Thereafter, a SiN passivation film (not shown) and a light shielding film pattern (not shown) were formed, and the α-Si TFT active matrix substrate 100 shown in FIG. 1 was manufactured. 1 is regularly formed on the glass substrate 1 of the α-Si TFT active matrix substrate 100. As shown in FIG. . That is, the α-Si TFT active matrix substrate 100 of Example 2 is an array substrate. The α-Si TFT active matrix substrate 100 corresponds to a preferred example of the thin film transistor substrate described in the claims, as in the first embodiment.

  A TFT-LCD type flat display was manufactured by providing a liquid crystal layer and a color filter substrate on the α-Si TFT active matrix substrate 100. This TFT-LCD type flat display corresponds to an example of a thin film transistor type liquid crystal display device described in claims. As a result of a dot inspection on the TFT-LCD type flat display, there was no defect of the pixel electrode, and a good display was obtained.

The α-SiTFT active matrix substrate 100 in Example 3 is substantially the same as that in FIG. 1 except that the composition of the transparent conductive film 9 in the α-SiTFT active matrix substrate 100 in Examples 1 and 2 is different. . Therefore, the α-Si TFT active matrix substrate 100 of Example 3 will also be described with reference to FIG.
On the light-transmitting glass substrate 1, metal Al (alloy) (its composition weight% is Al: Ni = 99: 1) was deposited by high frequency sputtering so as to have a film thickness of 2000 angstroms. Next, the deposited metal Al is deposited on the gate electrode of FIG. 1 by a photoetching method using a phosphoric acid / acetic acid / nitric acid / water (volume ratio of 9: 6: 1: 2) aqueous solution as an etching solution. 2 and the gate electrode wiring 12 were etched into the same shape to form a gate electrode and a gate electrode wiring. The glass substrate 1 corresponds to an example of a transparent substrate described in the claims.

  Next, a silicon nitride film (hereinafter also referred to as a SiN film) that becomes the gate insulating film 3 is formed on the glass substrate 1, the gate electrode 2, and the gate electrode wiring 12 by glow discharge CVD. The film was deposited so that the film thickness was 3000 angstroms. Subsequently, an α-Si: H (i) film 4 is deposited on the gate insulating film 3 so as to have a film thickness of 3500 angstroms, and further, a silicon nitride (SiN) film serving as the channel protective layer 5 Was deposited on the α-Si: H (i) film 4 so as to have a film thickness of 3000 Å.

At this time, the SiH ₄ —NH ₃ —N ₂ mixed gas is used as the discharge gas for the gate insulating film 3 and the channel protective layer 5 formed from the SiN film, while the α-Si: H (i) film is used. For No. ₄ , SiH ₄ —N ₂ mixed gas was used. Further, the channel protective layer 5 formed from this SiN film was etched by dry etching using a CHF-based gas to form the shape shown in FIG.

Subsequently, the α-Si: H (n) film 6 is formed on the α-Si: H (i) film 4 and the channel protective layer 5 by using a mixed gas of SiH ₄ —H ₂ —PH _3. The film was deposited so that the film thickness was 3000 angstroms.
Next, on the deposited α-Si: H (n) film 6, a metal Mo / metal Al bilayer film is further formed. The film thickness of the lower metal Mo is 0.05 μm, and the film thickness of the metal Al is The layers were sequentially deposited by sputtering so as to have a thickness of 0.2 μm.
This metal Mo / metal Al bilayer film is shown in FIG. 1 by a photoetching method using an aqueous solution of phosphoric acid / acetic acid / nitric acid / water (the volume ratio is 9: 6: 1: 2) as an etching solution. Etching into a shape made the pattern of the drain electrode 7 and the pattern of the source electrode 8.

Furthermore, α-Si: H formed from the α-Si: H film by using dry etching using a CHF-based gas and wet etching using a hydrazine (NH ₂ NH ₂ .H ₂ O) aqueous solution in combination. (I) The film 4 and the α-Si: H (n) film 6 are etched to form a pattern of the α-Si: H (i) film 4 having the shape shown in FIG. 1 and the α-Si: H (n) film. The pattern was 6. Further, as shown in FIG. 1, a protective film was formed using a transparent resin resist 10, and a pattern such as a through hole was further formed.

Next, as shown in FIG. 1, an amorphous transparent conductive film 9 mainly composed of indium oxide and niobium oxide was deposited on the substrate subjected to the above treatment by a sputtering method. The target used for this sputtering method was In ₂ O ₃ —Nb prepared so that the value of [In] / ([In] + [Nb]), which is the atomic ratio of In and Nb in the target, was 0.95. ₂ O ₅ sintered body. Here, [In] represents the number of indium atoms per unit volume in the transparent conductive film 9, and [Nb] represents the number of niobium atoms per unit volume in the transparent conductive film 9.

For sputtering, this In ₂ O ₃ —Nb ₂ O ₅ sintered body was used by placing it on a planar magnetron type cathode, and a transparent conductive film 9 was deposited so that its film thickness became 1000 Å. At this time, as the discharge gas at the time of sputtering, pure argon gas or argon gas mixed with a trace amount of O ₂ gas of about 1 vol% was used.
The form in which the niobium element is contained in the target may be a form of niobium oxide such as Nb ₂ O ₅ or Nb ₂ O ₃ and dispersed in the indium oxide sintered body. However, it may be in the form of a complex oxide of indium and niobium such as InNbO ₄ and dispersed in the indium oxide sintered body. Preferably, niobium atoms are dispersed and dissolved in the indium sites of indium oxide, so that niobium is dispersed at the atomic level in the indium oxide sintered body. Thus, it is more effective for the niobium to be dispersed in the indium oxide sintered body at the atomic level in order to obtain a low-resistance transparent conductive film 9 with stable discharge in sputtering.

The relative density of the target made of this In ₂ O ₃ —Nb ₂ O ₅ sintered body was 97%. In addition, according to another test, when the relative density of the target made of the In ₂ O ₃ —Nb ₂ O ₅ sintered body is 95% or more, it has been confirmed that no nodules and abnormal discharge occur.
Further, when the transparent conductive film 9 which is an In ₂ O ₃ —Nb ₂ O ₅ film formed by sputtering is analyzed by X-ray diffraction, no peak is observed and the film is found to be an amorphous film. did. Moreover, the specific resistance of the transparent conductive film 9 which is this In ₂ O ₃ —Nb ₂ O ₅ film is about 3.6 × 10 ⁻⁴ Ω · cm, and it can be confirmed that the film can be used as a sufficient electrode. It was. In addition, the specific resistance of the transparent conductive film 9 formed by adding 1 to 10% of tin oxide to the target composed of the In ₂ O ₃ —Nb ₂ O ₅ sintered body is 1.7 × 10 6. It was also found to be ^-4 Ω · cm or less.

The transparent conductive film 9 which is this In ₂ O ₃ —Nb ₂ O ₅ film was etched so as to form a transmissive pixel electrode pattern by a photo-etching method using an aqueous solution of 3.2 wt% oxalic acid as an etchant. . As a result, a transmissive pixel electrode pattern made of an amorphous electrode of the transparent conductive film 9 shown in FIG. 1 was formed. The aqueous solution of 3.2 wt% oxalic acid corresponds to an example of an acidic etchant containing oxalic acid described in the claims.

At this time, the pattern of the source electrode 8 and the transmissive pixel electrode pattern were formed in a desired pattern so as to be electrically connected. At this time, the source electrode 8 and the drain electrode 7 were not disconnected or thinned during etching. Next, this glass substrate 1 was heat-treated at 250 ° C. for 30 minutes.
Thereafter, an α-Si TFT active matrix substrate 100 shown in FIG. 1 was manufactured by forming a SiN passivation film (not shown) and a light shielding film pattern (not shown). 1 is regularly formed on the glass substrate 1 of the α-Si TFT active matrix substrate 100. As shown in FIG. That is, the α-Si TFT active matrix substrate 100 of Example 3 is an array substrate. The α-Si TFT active matrix substrate 100 corresponds to a preferred example of the thin film transistor substrate described in the claims as in the first and second embodiments.

  A TFT-LCD type flat display was manufactured by providing a liquid crystal layer and a color filter substrate on the α-Si TFT active matrix substrate 100. This TFT-LCD type flat display corresponds to an example of a liquid crystal display device described in claims. This TFT-LCD type flat display was subjected to a dot inspection, and as a result, it was found that the display was good.

  The α-Si TFT active matrix substrate 100 in Example 4 is substantially the same as FIG. 1 except for the composition of the transparent conductive film 9 of the α-Si TFT active matrix substrate 100 in Examples 1 to 3 described above. Therefore, the α-Si TFT active matrix substrate 100 of Example 4 will also be described with reference to FIG.

  As shown in FIG. 1, a metal Al (alloy) (its composition weight% is Al: Ni = 99: 1) is formed on a translucent glass substrate 1 by high-frequency sputtering to have a film thickness of 2000 angstroms. To be deposited. The deposited thin film made of Al is formed into a shape shown in FIG. 1 by a photoetching method using an aqueous solution of phosphoric acid / acetic acid / nitric acid / water (volume ratio is 9: 6: 1: 2) as an etching solution. The gate electrode 2 and the gate electrode wiring 12 were formed. The glass substrate 1 corresponds to an example of a transparent substrate described in the claims.

  Next, as shown in FIG. 1, a silicon nitride film (hereinafter also referred to as a SiN film) to be the gate insulating film 3 was deposited by a glow discharge CVD method to a thickness of 3000 angstroms. Subsequently, as shown in FIG. 1, an α-Si: H (i) film 4 is deposited so as to have a film thickness of 3500 angstroms, and a silicon nitride film (SiN) to be a channel protective layer 5 is further formed. The spine was deposited so that the film thickness was 3000 angstroms.

At this time, the SiH ₄ —NH ₃ —N ₂ mixed gas is used for the gate insulating film 3 and the channel protective film 5 formed of the SiN film as the discharge gas, while the α-Si: H (i) film 4 is used. for, using a mixed gas of _SiH 4 -N ₂ system, respectively. Further, the channel protective film 5 made of this SiN film was etched by dry etching using a CHF-based gas to form the shape shown in FIG.

Subsequently, an α-Si: H (n) film 6 was deposited using a SiH ₄ —H ₂ —PH ₃ -based mixed gas so as to have a film thickness of 3000 Å as shown in FIG.
Next, on this deposited α-Si: H (n) film 6, a bilayer film of metal Mo / metal Al (alloy) (its composition weight% is Al: Ni = 99: 1) is further formed. The lower layer Mo was deposited by sputtering in order so that the film thickness of Mo became 0.05 μm and the film thickness of upper layer Al became 0.2 μm.
This metal Mo / metal Al bilayer film is etched into the shape shown in FIG. 1 by a photo-etching method using phosphoric acid / acetic acid / nitric acid / water (the deposition ratio is 9: 6: 1: 2). The pattern of the drain electrode 7 and the pattern of the source electrode 8 were used.

Next, by using dry etching using a CHF-based gas and wet etching using a hydrazine (NH ₂ NH ₂ .H ₂ O) aqueous solution, α-Si: formed from the α-Si: H film: A pattern of H (i) film 4 and a pattern of α-Si: H (n) film 6 were formed. Moreover, as shown in FIG. 1, the protective film was formed using the transparent resin resist 10, and patterns, such as a through hole, were formed after that.

Next, an amorphous transparent conductive film 9 mainly composed of indium oxide and nickel oxide was deposited on the substrate subjected to the above treatment by a sputtering method. The target used for this sputtering was In ₂ O ₃ − prepared so that the value of [In] / ([In] + [Ni]), which is the atomic ratio of In to Ni in the target, was 0.95. NiO sintered body. Here, [In] represents the number of indium atoms per unit volume in the transparent conductive film 9, and [Ni] represents the number of nickel atoms per unit volume in the transparent conductive film 9.

For sputtering, the In ₂ O ₃ —NiO sintered body was used on a planar magnetron type cathode, and a transparent conductive film 9 was deposited so that the film thickness was 1000 angstroms. At this time, pure argon or Ar gas mixed with a total amount of O ₂ gas of about 1 vol% was used as a discharge gas during sputtering.

The form in which the nickel element is included in the target may be a form in which nickel oxide such as NiO is dispersed in the indium oxide sintered body. However, it may be in the form of a composite oxide of indium and nickel such as In ₂ NiO ₄ and dispersed in the indium oxide sintered body. Preferably, nickel atoms are dispersed and dissolved in the indium sites of indium oxide, so that nickel is dispersed at the atomic level in the indium oxide sintered body. Thus, it is effective for nickel to be dispersed in the indium oxide sintered body at the atomic level in order to obtain a low resistance transparent conductive film 9 with stable discharge in sputtering. The relative density of the target made of this In ₂ O ₃ —NiO sintered body was 97%. According to another test, it has been confirmed that no nodule or abnormal discharge occurs when the relative density of the target composed of the In ₂ O ₃ —NiO sintered body is 95% or more.

Further, when the transparent conductive film 9 which is an In ₂ O ₃ —NiO film formed by sputtering is analyzed by an X-ray diffraction method, no peak is observed and it is found that the film is an amorphous film. Moreover, the specific resistance of the transparent conductive film 9 which is this In ₂ O ₃ —NiO film is about 4.6 × 10 ⁻⁴ Ω · cm, and it was confirmed that the film can be used as a sufficient electrode. It was also found that the specific resistance of the formed transparent conductive film 9 was 2.2 × 10 ⁻⁴ Ω · cm or less by adding 1 to 10 wt% of tin oxide to the target.

The transparent conductive film 9 that is this In ₂ O ₃ —NiO film was etched by a photoetching method using an aqueous solution of 3.2% by weight of oxalic acid as an etchant so as to form a transmissive pixel electrode pattern. As a result, a transparent pixel electrode pattern made of an amorphous electrode of the transparent conductive film 9 shown in FIG. 1 was formed.
At this time, the pattern of the source electrode 8 and the transmissive pixel electrode pattern made of the transparent conductive film 9 were formed in a desired pattern so as to be electrically connected. At this time, the drain electrode 7 and the source electrode 8 of metal Al were not disconnected or thinned during the etching. Next, this glass substrate 1 was heat-treated at 250 ° C. for 30 minutes. The 3.2% by weight aqueous solution of oxalic acid corresponds to the acidic etchant containing oxalic acid described in the claims.

  Thereafter, a SiN passivation film (not shown) and a light shielding film pattern (not shown) were formed, and the α-Si TFT active matrix substrate 100 shown in FIG. 1 was manufactured. 1 is regularly formed on the glass substrate 1 of the α-Si TFT active matrix substrate 100. As shown in FIG. . That is, the α-Si TFT active matrix substrate 100 of Example 4 is an array substrate. The α-Si TFT active matrix substrate 100 corresponds to a preferred example of the thin film transistor substrate described in the claims, as in the first embodiment.

  A TFT-LCD type flat display was manufactured by providing a liquid crystal layer and a color filter substrate on the α-Si TFT active matrix substrate 100. This TFT-LCD type flat display corresponds to an example of a thin film transistor type liquid crystal display device described in claims. As a result of a dot inspection on the TFT-LCD type flat display, there was no defect of the pixel electrode, and a good display was obtained.

  In the said Examples 1-4, about the etchant used when etching the transparent conductive film 9, the example which is 3.2 wt% of oxalic acid aqueous solution was shown. However, the etchant used for etching the transparent conductive film 9 is preferably a mixed acid composed of phosphoric acid, acetic acid and nitric acid in addition to the oxalic acid aqueous solution, or may be a ceric ammonium nitrate aqueous solution. preferable.

As described in Examples 1 to 4, various oxides were used as the transparent conductive films 9 in the present embodiment. In Example 6, the electrode potential of these oxides with respect to an Ag / AgCl standard electrode was measured. The measurement was performed by measuring the electrode potential in various electrolytes (liquids).
Table 1 shows a measurement example in the case of using a TMAH (tetramethylammonium hydroxide) 2.8 wt% aqueous solution as the electrolyte. On the other hand, Table 2 shows a measurement example when a stripping solution is used as the electrolyte.

表１に示されているように、上記実施例１において用いたＩｎ_２Ｏ_３−ＷＯ_３による透明導電膜の電位（対Ａｇ／ＡｇＣｌ電極）は、−０．３５２Ｖであった。Ａｌとの電位差の絶対値は、０．５４３Ｖである（表１参照）。

As shown in Table 1, the potential (vs. Ag / AgCl electrode) of the transparent conductive film of In ₂ O ₃ —WO ₃ used in Example 1 was −0.352V. The absolute value of the potential difference from Al is 0.543 V (see Table 1).

Further, the potential of the transparent conductive film made of In ₂ O ₃ —MoO ₃ used in Example 2 (vs. Ag / AgCl electrode) was −0.386 V (see Table 1). The absolute value of the potential difference from Al is 0.509 V (see Table 1).
Further, the potential of the transparent conductive film by In ₂ O ₃ —Nb ₂ O ₅ used in Example 3 (vs. Ag / AgCl electrode) was −0.365 V (see Table 1). The absolute value of the potential difference from Al is 0.530 V (see Table 1).
Further, the potential of the transparent conductive film by In ₂ O ₃ —NiO used in Example 4 (vs. Ag / AgCl electrode) was −0.378 V (see Table 1). The absolute value of the potential difference from Al is 0.517 V (see Table 1).

  On the other hand, the potential of the transparent conductive film made of ITO (vs. Ag / AgCl electrode) was −0.238 V (see Table 1). The absolute value of the potential difference from Al is 0.657 V (see Table 1).

  The potential of the transparent conductive film by IZO (vs. Ag / AgCl electrode) was −0.247 V (see Table 1). The absolute value of the potential difference from Al is 0.648 V (see Table 1).

  Now, the potential of Al (vs. Ag / AgCl electrode) that has been compared so far is −0.895 V (see Table 1), and the potential of Al—Nd (Nd composition ratio: 1 wt%) alloy (vs. Ag / AgCl electrode) was −0.848 V (see Table 1).

  As described above, when Al and the transparent electrode are in electrical contact with each other and the electrolyte is also contacted, a potential difference (electromotive force) as shown in Table 1 is generated. This potential difference (electromotive force) is considered to accelerate the corrosion of the Al electrode. As shown in Table 1, the transparent electrode of the present invention can reduce the potential difference (electromotive force) from Al by about 0.1 V or more as compared with ITO or IZO. Thus, according to the present invention, since the potential difference (electromotive force) is reduced, it is clear that the corrosion reaction of the electrode is suppressed.

  Next, Table 2 shows the measurement results when the electrolyte was used as the stripping solution. This stripping solution is a solution in which diethanolamine and N-methylpyrrolidone are mixed at 30 vol%: 70 vol%.

表２に示されているように、上記実施例１において用いたＩｎ_２Ｏ_３−ＷＯ_３による透明導電膜の電位（対Ａｇ／ＡｇＣｌ電極）は、−０．２４８Ｖであった。Ａｌとの電位差の絶対値は、０．４７２Ｖである（表２参照）。

As shown in Table 2, the potential (vs. Ag / AgCl electrode) of the transparent conductive film of In ₂ O ₃ —WO ₃ used in Example 1 was −0.248V. The absolute value of the potential difference from Al is 0.472 V (see Table 2).

The potential of the transparent conductive film made of In ₂ O ₃ —MoO ₃ used in Example 2 (vs. Ag / AgCl electrode) was −0.268 V (see Table 2). The absolute value of the potential difference from Al is 0.452 V (see Table 2).
Further, the potential of the transparent conductive film by In ₂ O ₃ —Nb ₂ O ₅ used in Example 3 (vs. Ag / AgCl electrode) was −0.256 V (see Table 2). The absolute value of the potential difference from Al is 0.464 V (see Table 2).

Further, the potential of the transparent conductive film by In ₂ O ₃ —NiO used in Example 4 (vs. Ag / AgCl electrode) was −0.287 V (see Table 2). The absolute value of the potential difference from Al is 0.433 V (see Table 2).

  On the other hand, the potential of the transparent conductive film made of ITO (vs. Ag / AgCl electrode) was −0.120 V (see Table 2). The absolute value of the potential difference from Al is 0.600 V (see Table 2).

  Now, the potential of Al that has been compared so far (vs. Ag / AgCl electrode) is −0.720 V (see Table 2).

  As described above, when Al and the transparent electrode are in electrical contact with each other and the electrolyte is also contacted, a potential difference (electromotive force) as shown in Table 2 is generated. This potential difference (electromotive force) is considered to accelerate the corrosion of the Al electrode. As shown in Table 2, the transparent electrode of the present invention can reduce the potential difference (electromotive force) from Al by about 0.1 V or more as compared with ITO or IZO. Thus, according to the present invention, since the potential difference (electromotive force) is reduced, it is clear that the corrosion reaction of the electrode is suppressed.

"Modification Example 1"
FIG. 2 shows a cross-sectional view of the vicinity of another α-Si TFT active matrix substrate 200 in this embodiment. A characteristic feature of the α-Si TFT active matrix substrate 200 of the first modification is that the transparent conductive film 9 is provided directly on the source electrode 108 without providing the transparent resin resist as shown in FIG. is there.
Further, as shown in FIG. 2, the drain electrode 7 and the source electrode 8 of the present modified example 1 are composed of a metal Cr / metal Al bilayer film. It is also preferable that the electrode 7 and the source electrode 8 are composed of a metal Mo / metal Al bilayer film. 2, the lower layer is a layer made of metal Cr, and the upper layer is a layer made of metal Al.

In addition, as shown in FIG. 2, the gate electrode 102 in the present modified example 1 has an example of a single layer structure composed of a metal Al layer. Similarly to the gate electrode 2, it is also preferable to have a two-layer structure composed of an Al layer and a Mo layer. Similarly to Example 3, it is also preferable that the metal Al layer is composed of metal Al (alloy) (its composition weight% is Al: Ni = 99: 1).
Note that the α-Si TFT active matrix substrate 200 of the first modification shown in FIG. 2 has the same operational effects as the α-Si TFT active matrix substrate 100 of the first to fourth embodiments.

It is sectional drawing of the vicinity of the alpha-SiTFT active matrix substrate of the Examples 1-3. It is sectional drawing of the vicinity of the alpha-SiTFT active matrix substrate of this modification 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Glass substrate 2 Gate electrode 3 Gate insulating film 4 α-Si: H (i) film 5 Channel protective layer 6 α-Si: H (n) film 7 Drain electrode 8 Source electrode 9 Transparent conductive film 10 Transparent resin resist 11 Reflection Electrode 12 Gate electrode wiring 100 α-Si TFT active matrix substrate 102 Gate electrode 107 Drain electrode 108 Source electrode 200 α-Si TFT active matrix substrate

Claims (4)

A transparent substrate;
A source electrode provided on the transparent substrate;
A drain electrode provided on the transparent substrate;
A transparent pixel electrode provided on the transparent substrate;
In the thin film transistor substrate, the transparent pixel electrode comprises:
Indium oxide as a main component, and one or more oxides selected from tungsten oxide, molybdenum oxide, nickel oxide, and niobium oxide,
A thin film transistor type substrate, wherein the transparent pixel electrode is electrically connected to the source electrode or the drain electrode. A thin film transistor substrate comprising: a transparent substrate; a source electrode provided on the transparent substrate; a drain electrode provided on the transparent substrate; and a transparent pixel electrode provided on the transparent substrate; ,
A color filter substrate provided with a coloring pattern of a plurality of colors;
A liquid crystal layer sandwiched between the thin film transistor substrate and the color filter substrate;
In the thin film transistor type liquid crystal display device comprising the transparent pixel electrode,
Indium oxide as a main component, and one or more oxides selected from tungsten oxide, molybdenum oxide, nickel oxide, and niobium oxide,
A thin film transistor type liquid crystal display device, wherein the transparent pixel electrode is electrically connected to the source electrode or the drain electrode. In the method of manufacturing the thin film transistor substrate according to claim 1,
Depositing the transparent conductive film on the transparent substrate;
Etching the deposited transparent conductive film using an acidic etchant to form the transparent pixel electrode;
A method of manufacturing a thin film transistor substrate, comprising: The acidic etchant
4. The method of manufacturing a thin film transistor substrate according to claim 3, comprising one or more of oxalic acid, a mixed acid composed of phosphoric acid / acetic acid / nitric acid, or ceric ammonium nitrate.

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