JP2005250191A - Translucent / half-reflection electrode substrate, and method for manufacturing same, and liquid crystal display device using translucent / half-reflection electrode substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a translucent / half-reflection electrode substrate equipped with a transparent conductive layer which hardly produces any residue or the like resulting from etching and further which is resistant to an etchant for a metal reflection layer (a metal layer), a method for manufacturing the same, and a liquid crystal display device using the translucent / half-reflection electrode substrate. <P>SOLUTION: The translucent / half-reflection electrode substrate is equipped with the transparent substrate, the transparent conductive layer disposed on the transparent substrate and containing indium oxide as a main component, and further, one or more kinds of oxides selected from tungsten oxide, molybdenum oxide and niobium oxide, and the metal reflection layer disposed on the transparent substrate, reflecting external light and further electrically connected to the transparent conductive layer. The method for manufacturing the translucent / half-reflection electrode substrate and the liquid crystal display device using the translucent / half-reflection electrode substrate are also disclosed. The translucent / half-reflection electrode substrate hardly produces any residue, is superior in workability and brings about an improved yield. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a transflective / semireflective electrode substrate used in a transflective liquid crystal display device. The present invention also relates to a method of manufacturing the transflective / semireflective electrode substrate, and to a liquid crystal display device using the manufactured transflective / semireflective electrode substrate.

  The transflective liquid crystal display device is a liquid crystal display device that includes both a reflective electrode and a transparent electrode. For this reason, this device has the function of a transmissive liquid crystal display device and the function of a reflective liquid crystal display device at the same time. Conventionally, this transflective liquid crystal display device has been intensively researched and developed for the following reasons.

(1) Since the liquid crystal display device is a semi-transmissive / semi-reflective type, it can be used as a reflective type for performing liquid crystal display using outside light when outdoors with relatively strong external light, It can be used as a transmission type that performs liquid crystal display using a backlight. For this reason, it can be displayed with high brightness regardless of whether it is outdoors or indoors.
(2) When used in a bright place (place with strong external light), the liquid crystal display device can be used as a reflection type, so that power consumption can be saved.
(3) Since it can be used outdoors as a reflection type, it can operate with low power consumption. For this reason, it is suitable for a portable display.
(4) Full color is easy.

  However, in the transflective liquid crystal, it is necessary to install the reflective electrode and the transparent electrode in the same pixel in the electrode section for driving the liquid crystal, which makes the manufacturing process complicated, resulting in a decrease in yield and an increase in price. There is a problem that the liquid crystal display is difficult to see because the liquid crystal display looks different between the reflective type and the transmissive type.

Therefore, in the following patent document 1 and the following patent document 2, after forming a silver reflective film, the silver reflective film is covered with a protective film, and a transparent electrode for driving a liquid crystal is provided thereon. A liquid crystal driving electrode is disclosed. The silver reflective layer and the transparent electrode for driving the liquid crystal are alternately arranged to form a transflective liquid crystal drive electrode that exhibits a transflective function.
Patent Document 3 below discloses a transflective film in which a Si thin film or the like having an auxiliary reflective function is disposed under a metallic transflective layer.

JP 2002-49034 A JP 2002-49033 A JP 2001-305529 A

  However, according to Patent Documents 1 to 3 and the like, the transparent electrode portion and the reflective electrode portion are etched separately. For this reason, in order to form a layer to be a transparent electrode portion and a layer to be a reflective electrode portion, it is necessary to perform a repeated process of “film formation—etching by photolithography—film formation—etching by photolithography”. . At this time, the layer that becomes the transparent electrode portion and the layer that becomes the reflective electrode portion are electrically connected, and the battery reaction is caused by the developer, etchant, or release agent used when etching these electrode layers. May occur, and the reflective substrate (reflecting electrode portion) may be locally corroded.

  Further, when the reflective electrode is provided on the transparent electrode, the transparent electrode may be damaged when the reflective electrode is etched. In particular, ITO (indium-tin oxide) is generally used as the material used for the transparent electrode, and Al is used as the material used for the reflective electrode, but ITO is in contact with Al. If so, there is a problem that battery reaction is likely to occur.

  Further, in the case of crystalline ITO, etching cannot be performed unless strong acid such as aqua regia or hydrochloric acid is used. For example, there is a problem that the wiring material of the TFT is corroded. 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. On the other hand, although IZO (registered trademark: Idemitsu Kosan Co., Ltd., indium-zinc oxide) has been devised as an amorphous material, this material has a reflective electrode containing Al on a transparent electrode. Since it has the property of dissolving even with an Al etchant, it was difficult to use.

The present invention has been made in view of the above problems, and provides a transflective / semi-reflective electrode substrate having a transparent electrode that hardly generates residues due to etching and is resistant to an etchant of a reflective electrode. For the purpose. Another object of the present invention is to provide a production method capable of efficiently obtaining the transflective / semi-reflective electrode substrate.
Still another object of the present invention is to provide a liquid crystal display device using the transflective / semi-reflective electrode substrate.

  (1) Therefore, in order to solve the above-mentioned problem, the first transflective / semi-reflective electrode substrate of the present invention is provided on a transparent substrate and the transparent substrate, and contains indium oxide as a main component, A transparent conductive layer containing one or more oxides selected from tungsten oxide, molybdenum oxide, and niobium oxide; and a transparent conductive layer that is provided on the transparent substrate, reflects external light, and is electrically connected to the transparent conductive layer. A semi-transmissive / semi-reflective electrode substrate comprising: a metal reflective layer connected to each other.

  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.

  By adding tungsten oxide, molybdenum oxide, or niobium oxide, the formed transparent conductive layer can be etched with an etchant containing oxalic acid after the transparent conductive layer is formed. The film formation substrate temperature is R.I. T.A. The temperature is preferably (room temperature) to 200 ° C, more preferably 80 ° C to 180 ° C. 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. This is because etching with an etchant containing oxalic acid may not be possible due to crystallization of the layer. Further, water or hydrogen can be added to the atmospheric gas during film formation. Thereby, it becomes easy to etch the formed transparent conductive layer using the etchant containing oxalic acid, and the residue can be further reduced.

Further, after the formed transparent conductive layer is etched by adding the metal oxide, the transparent conductive layer on the substrate can be easily crystallized by heating the temperature of the substrate to 200 ° C. or higher. . This crystallization temperature is suitably 220 ° C. or higher, more preferably 230 ° C. or higher.
By crystallizing the transparent conductive layer, it is possible to avoid damage to the transparent conductive layer due to the etchant in the mixed acid of phosphoric acid, acetic acid and nitric acid which is the etchant of the metal reflection layer. Further, the battery reaction can be suppressed by adding tungsten oxide, molybdenum oxide, or niobium oxide to the transparent conductive layer.

  The film thickness of a transparent conductive layer 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 thickness of the transparent conductive layer is less than 20 nm, the surface resistance of the transparent conductive layer may increase. On the other hand, if the thickness of the transparent conductive layer exceeds 500 nm, the transmittance may decrease or the processing accuracy may be problematic. May occur.

  The reflectance of the metal reflective layer is preferably 80% or more. The reflectance according to the present invention is measured using a graph in which the vertical axis (Y axis) represents the reflectance and the horizontal axis (X axis) represents the wavelength. That is, in the measurement range at wavelengths of 400 to 700 nm in this graph, the reflectance is defined as 100 when the reflectance at each wavelength is 100%, and with respect to this area, a metal reflective layer (or metal layer) ) Is defined as a value expressed as a percentage of the area of the measured data.

  Here, the area is an area surrounded by the X axis and the reflectance spectrum in the measurement range of wavelength 400 to 700 nm in the graph. Needless to say, this area is equal to the integrated value from 400 to 700 nm for the reflectance spectrum.

The film thickness of the metal reflective layer is preferably 10 to 1000 nm, more preferably 30 to 300 nm, and still more preferably 50 to 200 nm. If the thickness of the metal reflective layer is less than 10 nm, the reflectivity may not be 80% or more, while if it exceeds 1000 nm, there may be a problem in processing accuracy.
The transparent conductive layer has a function of substantially transmitting light, while the metal reflective layer has a function of substantially reflecting light. By simultaneously providing the transparent conductive layer having such a function and the metal reflective layer electrically connected to the transparent conductive layer, a semi-transmissive / semi-reflective electrode substrate is obtained.

  (2) Moreover, this invention contains In in the said transparent conductive layer which contains indium oxide as a main component, and also contains the said oxide of 1 type, or 2 or more types chosen from tungsten oxide, molybdenum oxide, and niobium oxide. The first semi-transmissive / semi-reflective electrode substrate according to claim 1, wherein a value of [In] / [all metals], which is a composition ratio, is 0.85 to 0.99.

  The composition of the transparent conductive layer is such that the In composition ratio (hereinafter sometimes referred to as the atomic ratio) as an atomic ratio is [In] / [all metals] = 0.85 to 0.99. If the In composition ratio is less than 0.85, the resistance value of the transparent conductive layer may increase, or the transparent conductive layer may not crystallize even if the substrate on which the transparent conductive layer is formed is heated to 200 ° C. or higher. . If the In composition ratio exceeds 0.99, when the transparent conductive layer is formed, the transparent conductive layer 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, and [All metals] represents the number of all metal atoms in the transparent conductive layer per unit volume.

Moreover, Sn and Zn can be added to the said transparent conductive layer as a 3rd atom. Note that the first atom is an indium atom in indium oxide, and the second atom is a tungsten atom in one or more oxides selected from tungsten oxide, niobium oxide, and molybdenum oxide, A niobium atom and a molybdenum oxide 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 layer is 0.2 or more, a residue may be generated during etching. Here, [Sn] represents the number of tin atoms per unit volume.

  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. When the value of [Zn] / [all metals] in the transparent conductive layer is 0.1 or more, the transparent conductive layer is damaged when the metal reflective layer is etched by a mixed acid containing phosphoric acid, acetic acid and nitric acid. There is. Here, [Zn] represents the number of zinc atoms per unit volume.

(3) Further, the present invention provides the first transflective / semi-reflective electrode substrate, wherein the metal reflective layer has a layer containing Al or Ag as a component.
As a component of a layer (a layer containing Al or Ag as a component) included in the metal reflection layer, in addition to Al or Ag, a lanthanoid metal such as Nd, Co, Ni, Pd, Au, Zr, Pt, Cu, etc. Heavy metals can be added.

  The content of the added lanthanoid metal and heavy metal is preferably 0.1 to 5 wt%, more preferably 0.5 to 3 wt%, and further preferably 0.5 to 2 wt%. When the content of the lanthanoid metal and heavy metal is less than 0.1 wt%, the addition effect may hardly appear. On the other hand, when the content of the lanthanoid metal and heavy metal is 5 wt% or more, the reflectivity of the metal reflection layer is low. It may decrease.

  (4) A second transflective / semi-reflective electrode substrate of the present invention is provided on a transparent substrate and the transparent substrate, contains indium oxide as a main component, and further comprises tungsten oxide, molybdenum oxide, and oxide. A transparent conductive layer containing one or more oxides selected from niobium, a TFT element provided on the transparent substrate, the transparent conductive layer provided on the transparent substrate, and the TFT element A semi-transmissive / semi-reflective electrode substrate, wherein the metal layer has a reflectance of 80% or more.

  The TFT element is a Thin Film Transistor (thin film transistor). By adding tungsten oxide, molybdenum oxide, or niobium oxide, the formed transparent conductive layer can be etched with an etchant containing oxalic acid after the transparent conductive layer is formed. The film formation substrate temperature is R.I. T.A. It is preferably (room temperature) to 200 ° C, more preferably 80 ° C to 180 ° C. 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, when the substrate temperature is 200 ° C. or higher, transparent conductive This is because etching with an etchant containing oxalic acid may not be possible due to crystallization of the layer. Further, water or hydrogen can be added to the atmospheric gas during film formation. Thereby, it becomes easy to etch the formed transparent conductive layer using the etchant containing oxalic acid, and the residue can be further reduced.

  Further, after the formed transparent conductive layer is etched by adding the metal oxide, the transparent conductive layer on the substrate can be easily crystallized by heating the temperature of the substrate to 200 ° C. or higher. . This crystallization temperature is suitably 220 ° C. or higher, more preferably 230 ° C. or higher. By crystallizing the transparent conductive layer, it is possible to avoid damage to the transparent conductive layer due to the etchant in the mixed acid of phosphoric acid, acetic acid and nitric acid which is the etchant of the metal reflection layer.

The film thickness of a transparent conductive layer 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 thickness of the transparent conductive layer is less than 20 nm, the surface resistance of the transparent conductive layer may increase. On the other hand, if the thickness of the transparent conductive layer exceeds 500 nm, the transmittance decreases or the processing accuracy increases. Problems may arise.
The film thickness of the metal reflective layer is preferably 10 to 1000 nm, more preferably 30 to 300 nm, and still more preferably 50 to 200 nm. If the thickness of the metal reflective layer is less than 10 nm, the reflectivity may not be 80% or more, while if it exceeds 1000 nm, there may be a problem in processing accuracy.

  The transparent conductive layer has a function of substantially transmitting light, while the metal layer has a function of substantially reflecting light. By electrically connecting the transparent conductive layer and the TFT element by a metal layer, the transparent conductive layer and the metal layer function as electrodes used in a liquid crystal display device, and the metal layer Since the reflectance is 80% or more, the metal layer functions as a reflective electrode. Thus, by providing the metal layer functioning as the reflective electrode and the transparent conductive layer at the same time, the intended transflective / semi-reflective electrode substrate is obtained.

  (5) In addition, the present invention includes In in the transparent conductive layer containing indium oxide as a main component and further containing one or more oxides selected from tungsten oxide, molybdenum oxide, and niobium oxide. The second semi-transmissive / semi-reflective electrode substrate is characterized in that the value of [In] / [all metals], which is the composition ratio, is 0.85 to 0.99.

  The composition of the transparent conductive layer is such that the atomic composition ratio of In is [In] / [all metals] = 0.85 to 0.99. If the In composition ratio is less than 0.85, the resistance value of the transparent conductive layer may increase, or the transparent conductive layer may not crystallize even if the substrate on which the transparent conductive layer is formed is heated to 200 ° C. or higher. . If the In composition ratio exceeds 0.99, when the transparent conductive layer is formed, the transparent conductive layer is crystallized and cannot be etched with an etchant containing oxalic acid, or a large amount of residue is generated. Because there is.

Moreover, Sn and Zn can be added to the said transparent conductive layer as a 3rd 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 layer is 0.2 or more, a residue may be generated during etching.
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. When the value of [Zn] / [all metals] in the transparent conductive layer is 0.1 or more, the transparent conductive layer is damaged when the metal reflective layer is etched by a mixed acid containing phosphoric acid, acetic acid and nitric acid. There is.

(6) Further, the present invention is the second transflective / semi-reflective electrode substrate, wherein the metal layer having a reflectance of 80% or more has a layer containing Al or Ag as a component. .
If the reflectance of the metal layer is not 80% or more, the reflectance of external light may be low, and the liquid crystal display may be difficult to see. As a component of a layer (a layer containing Al or Ag as a component) included in the metal layer, in addition to Al or Ag, a lanthanoid metal such as Nd, Co, Ni, Pd, Au, Zr, Pt, Cu, etc. It is also preferable to add heavy metals.

  The content of the added lanthanoid metal and heavy metal is preferably 0.1 to 5 wt%, more preferably 0.5 to 3 wt%, and further preferably 0.5 to 2 wt%. When the content of lanthanoid metal and heavy metal is less than 0.1 wt%, the effect of addition may hardly appear. On the other hand, when the content of lanthanoid metal and heavy metal exceeds 5 wt%, the reflectivity of the metal layer decreases. There is a case to do.

  (7) In addition, the present invention includes indium oxide as a main component, and further includes one or more oxides selected from tungsten oxide, molybdenum oxide, and niobium oxide, and on the transparent substrate. Etching the transparent conductive layer deposited on the transparent conductive layer with an etchant containing oxalic acid, and etching the metal layer electrically connected to the transparent conductive layer with a mixed acid containing phosphoric acid / acetic acid / nitric acid. Forming a reflective layer. The method of manufacturing the first transflective / semi-reflective electrode substrate.

  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.

  The concentration of phosphoric acid, acetic acid and nitric acid in the mixed acid used for etching the metal layer can be selected as appropriate. The phosphoric acid concentration is preferably 40 to 95 wt%, and the acetic acid concentration is 5 to 60 wt%. The nitric acid concentration is preferably 0.5 to 5 wt%. This mixed acid can be diluted with water as appropriate.

  Before or after the metal layer is formed, the substrate on which the transparent conductive layer is formed is heated to 200 ° C. or higher, preferably 220 ° C. or higher, more preferably 230 ° C. or higher to form the transparent conductive layer. It is desirable to crystallize. By crystallizing the transparent conductive layer, damage to the transparent conductive layer when the metal layer is etched by a mixed acid of phosphoric acid, acetic acid, and nitric acid can be reduced.

  (8) Further, the present invention includes indium oxide as a main component, and further includes one or more oxides selected from tungsten oxide, molybdenum oxide, and niobium oxide, and on the transparent substrate. The step of etching the formed transparent conductive layer with an etchant containing oxalic acid, electrically connecting the transparent conductive layer and the TFT element, and having a reflectance of 80% or more Etching the metal layer with a mixed acid containing phosphoric acid, oxalic acid, and nitric acid. The method for producing the second transflective / semi-reflective electrode substrate.

  By electrically connecting the transparent conductive layer and the TFT element by the metal layer, the transparent conductive layer and the metal layer can function as a liquid crystal drive electrode of a TFT drive system. Further, as described above, the transparent conductive layer has a function of substantially transmitting light, and the metal layer has a function of substantially reflecting light. When the metal layer functions as a reflective electrode, a semi-transmissive / semi-reflective electrode substrate is obtained.

(9) Further, the present invention is a liquid crystal display device including the first or second transflective / semireflective electrode substrate and a liquid crystal layer driven by the transflective / semireflective electrode substrate.
Since the liquid crystal display device includes the first or second semi-transmissive / semi-reflective electrode substrate, it has a function as a reflective liquid crystal display device and a function as a transmissive liquid crystal display device at the same time.

  As described above, the semi-transmissive / semi-reflective electrode substrate according to the present invention has almost no generation of residues due to the etching of the transparent conductive layer using a weak acid (such as organic acid, particularly oxalic acid) at the time of manufacture, and the upper part thereof When the metal reflective layer (metal layer) is etched, a transparent conductive layer resistant to the etchant (mixed acid) of the metal reflective layer (metal layer) is provided. For this reason, the transflective / semi-reflective electrode substrate of the present invention is excellent in workability.

Further, according to the method for producing a transflective / semi-reflective electrode substrate of the present invention, there is almost no generation of residues due to etching of the transparent conductive layer using a weak acid (organic acid or the like, particularly oxalic acid), and the When etching a metal reflective layer (metal layer), it is possible to provide a transflective / semi-reflective electrode substrate having a transparent conductive layer resistant to an etchant (mixed acid) of the metal reflective layer (metal layer) It becomes. For this reason, the yield in the manufacturing process of this transflective / semi-reflective electrode substrate is improved.
In addition, the liquid crystal display device of the present invention is provided with the semi-transmissive / semi-reflective electrode substrate, thereby improving the production efficiency.

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

  FIG. 1 shows a partial cross-sectional view of an α-Si TFT (amorphous silicon thin film transistor) active matrix substrate 100 according to the first embodiment. On the translucent glass substrate 1, metal Al is deposited by high frequency sputtering so that the film thickness becomes 1500 angstroms, and metal Mo is deposited on this metal Al so that the film thickness becomes 500 angstroms. did. The glass substrate 1 corresponds to an example of a transparent substrate described in the claims.

Next, the deposited metal Al and metal Mo are 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. The gate electrode 2 and the gate electrode wiring 12 were formed by etching into the shape shown.
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 into the shape shown in FIG. 1 by dry etching using a CHF-based gas.

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 this deposited α-Si: H (n) film 6, a metal Mo / metal Al / metal Mo three-layer film is formed, and the thickness of the lower metal Mo becomes 0.05 μm. The layers were sequentially deposited by sputtering so that the film thickness was 0.2 μm and the film thickness of the upper metal Mo was 0.05 μm.

This metal Mo / metal Al / metal Mo three-layer film is formed by a photoetching method using a phosphoric acid / acetic acid / nitric acid / water (volume ratio of 9: 8: 1: 2) aqueous solution as an etching solution. Etching into the shape shown in FIG. 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 10a was formed.

On the gate insulating film 3, an amorphous transparent conductive film 9 containing indium oxide as a main component and further containing tungsten oxide was deposited by sputtering. 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, and [W] represents the number of tungsten atoms per unit volume.

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 transparent conductive film 9 corresponds to an example of the transparent conductive layer described in the claims.

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.

When the transparent conductive film 9, which was an In ₂ O ₃ —WO ₃ film formed by 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 —WO ₃ film is about 3.8 × 10 ⁻⁴ Ω · cm, and it was found that the film can be used as a sufficient electrode.

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. The aqueous solution of 3.2 wt% oxalic acid corresponds to an example of an etchant containing oxalic acid described in the claims.

  Next, the substrate on which the transparent conductive film 9 is formed is heat-treated at 250 ° C. for 30 minutes, and then metal Mo is deposited on the transparent resin resist 10 by high frequency sputtering so that the film thickness becomes 500 angstroms. Then, metal Al was deposited on the metal Mo so as to have a film thickness of 2000 angstroms. When the reflectance of the layer composed of these metal Mo and metal Al was measured, the reflectance was 80% or more. In addition, the layer which consists of these metal Mo and metal Al is equivalent to an example of the metal layer as described in a claim.

  This metal Mo and metal Al are etched 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, and the reflection shown in FIG. A pattern of the electrode 11 was formed. At this time, as shown in FIG. 1, the pattern of the reflective electrode 11 made of the metal Mo and the metal Al is such that the pattern of the source electrode 8 and the pattern of the transmissive pixel electrode made of the transparent conductive film 9 are in electrical contact. The pattern was formed as follows. At this time, the drain electrode 7 and the source electrode 8 containing metal Al were not eluted with the etching solution. When the reflectance of the reflective electrode 11 was measured, the reflectance was 80% or more.

The reflective electrode 11 corresponds to an example of a metal reflective layer described in the claims, and a phosphoric acid / acetic acid / oxalic acid / water (volume ratio of 9: 6: 1: 2) aqueous solution is: This corresponds to an example of a mixed acid composed of phosphoric acid, acetic acid and nitric 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. A TFT-LCD type flat display was manufactured by providing a liquid crystal layer on the α-Si TFT active matrix substrate 100. The α-Si TFT active matrix substrate 100 corresponds to an example of the transflective / semi-reflective electrode substrate described in the claims, and the TFT-LCD type flat display is a liquid crystal display device described in the claims. It corresponds to an example.

  The α-Si TFT active matrix substrate 100 in Example 2 is the same as that in FIG. 1 except that the composition of the transparent conductive film 9 of the α-Si TFT active matrix substrate 100 in Example 1 is different. 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 is deposited on a translucent glass substrate 1 by high-frequency sputtering so that the film thickness becomes 1500 angstroms, and the film thickness is 500 angstroms on the metal Al. Metal Mo was deposited so as to be. Next, the deposited metal Al and metal Mo are 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. The gate electrode 2 and the gate electrode wiring 12 were formed by etching into the shape shown. 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. The channel protective layer 5 formed from this SiN film was etched into the shape shown in FIG. 1 by dry etching using a CHF-based gas.

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 this deposited α-Si: H (n) film 6, a metal Mo / metal Al / metal Mo three-layer film is formed, and the thickness of the lower metal Mo becomes 0.05 μm. The layers were sequentially deposited by sputtering so that the film thickness was 0.2 μm and the film thickness of the upper metal Mo was 0.05 μm.

This metal Mo / metal Al / metal Mo three-layer film is formed by a photoetching method using a phosphoric acid / acetic acid / nitric acid / water (volume ratio of 9: 8: 1: 2) aqueous solution as an etching solution. Etching into the shape shown in FIG. 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 10a was formed.

On this gate insulating film 3, an amorphous transparent conductive film 9 containing indium oxide as a main component and further containing molybdenum oxide was deposited by sputtering. The target used for this sputtering method was In ₂ O ₃ —MoO prepared so that the value of [In] / ([In] + [Mo]), which is the atomic ratio of In to Mo in the target, was 0.90. _Three sintered bodies. Here, [In] represents the number of indium atoms per unit volume, and [Mo] represents the number of molybdenum atoms per unit volume.

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, 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 transparent conductive film 9 corresponds to an example of the transparent conductive layer described in the claims.

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 InMo 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.

When the transparent conductive film 9 which is an In ₂ O ₃ —MoO ₃ film formed by sputtering is analyzed by an 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 —MoO ₃ film is about 3.4 × 10 ⁻⁴ Ω · cm, and it was found that the film can be sufficiently used as an electrode.
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. The aqueous solution of 3.2 wt% oxalic acid corresponds to the etchant containing oxalic acid described in the claims.

  Next, the substrate on which the transparent conductive film 9 is formed is heat-treated at 250 ° C. for 30 minutes, and then metal Mo is deposited by high frequency sputtering so that the film thickness becomes 500 angstroms. Metal Al was deposited so that the film thickness was 2000 angstroms. When the reflectance of the layer composed of these metal Mo and metal Al was measured, the reflectance was 80% or more. In addition, the layer which consists of these metal Mo and metal Al is equivalent to an example of the metal layer as described in a claim.

  This metal Mo and metal Al are etched 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, and the reflection shown in FIG. The electrode 11 was formed in a pattern. At this time, the pattern of the reflective electrode 11 was formed such that the pattern of the source electrode 8 and the transmissive pixel electrode pattern made of the transparent conductive film 9 were in electrical contact as shown in FIG. During this etching, the drain electrode 7 and the source electrode 8 containing metal Al were not disconnected or thinned. When the reflectance of the reflective electrode 11 was measured, the reflectance was 80% or more.

The reflective electrode 11 corresponds to an example of a metal reflective layer described in the claims, and a phosphoric acid / acetic acid / oxalic acid / water (volume ratio of 9: 6: 1: 2) aqueous solution is: This corresponds to an example of a mixed acid composed of phosphoric acid, acetic acid and 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. A TFT-LCD type flat display was manufactured by providing a liquid crystal layer on the α-Si TFT active matrix substrate 100. The α-Si TFT active matrix substrate 100 corresponds to an example of the transflective / semi-reflective electrode substrate described in the claims, and the TFT-LCD type flat display is a liquid crystal display device described in the claims. It corresponds to an example.

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

  As shown in FIG. 1, metal Al is deposited on a translucent glass substrate 1 by high-frequency sputtering so that the film thickness becomes 1500 angstroms, and the film thickness is 500 angstroms on the metal Al. Metal Mo was deposited so as to be. Next, the deposited metal Al and metal Mo are 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. The gate electrode 2 and the gate electrode wiring 12 were formed by etching into the shape shown. 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. The channel protective layer 5 formed from this SiN film was etched into the shape shown in FIG. 1 by dry etching using a CHF-based gas.

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 this deposited α-Si: H (n) film 6, a metal Mo / metal Al / metal Mo three-layer film is formed, and the thickness of the lower metal Mo becomes 0.05 μm. The layers were sequentially deposited by sputtering so that the film thickness was 0.2 μm and the film thickness of the upper metal Mo was 0.05 μm.

This metal Mo / metal Al / metal Mo three-layer film is formed by a photoetching method using a phosphoric acid / acetic acid / nitric acid / water (volume ratio of 9: 8: 1: 2) aqueous solution as an etching solution. Etching into the shape shown in FIG. 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.

On this gate insulating film 3, an amorphous transparent conductive film 9 containing indium oxide as a main component and further containing niobium oxide was deposited by sputtering. 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, and [Nb] represents the number of niobium atoms per unit volume.

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 transparent conductive film 9 corresponds to an example of the transparent conductive layer described in the claims.

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.

When the transparent conductive film 9 which is an In ₂ O ₃ —Nb ₂ O ₅ film formed by the above sputtering was analyzed by X-ray diffraction, 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 —Nb ₂ O ₅ film is about 3.6 × 10 ⁻⁴ Ω · cm, and it was found that the film can be used as a sufficient electrode. .

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 etchant containing oxalic acid described in the claims.

  Next, after the substrate on which the transparent conductive film 9 is formed is heat-treated at 250 ° C. for 30 minutes, a transparent resin resist 10 is formed on the TFT element and in the vicinity of the transmissive pixel electrode made of the transparent conductive film 9 with an interlayer insulating film. And the transparent resin resist 10 was formed in the pattern shown in FIG. 1 so that the function as a planarization layer for liquid crystal film thickness adjustment of the reflective electrode 11 may be exhibited. The TFT element is a thin film transistor and includes the gate electrode 2, the α-Si: H (i) film 4, the drain electrode 7, and the source electrode 8 shown in FIG. 1.

  A metal Mo was deposited on the transparent resist 10 by high frequency sputtering so that the film thickness was 500 angstroms, and a metal Al was deposited on the metal Mo so that the film thickness was 2000 angstroms. . When the reflectance of the layer composed of these metal Mo and metal Al was measured, the reflectance was 80% or more. In addition, the layer which consists of these metal Mo and metal Al is equivalent to an example of the metal layer as described in a claim.

  This metal Mo and metal Al are etched 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, and the reflection shown in FIG. A pattern of the electrode 11 was formed. At this time, the pattern of the reflective electrode 11 was formed so that the pattern of the source electrode 8 and the pattern of the transmissive pixel electrode made of the transparent conductive film 9 were in electrical contact as shown in FIG. At this time, the drain electrode 7 and the source electrode 8 containing metal Al were not eluted with the etching solution. When the reflectance of the reflective electrode 11 was measured, the reflectance was 80% or more.

The reflective electrode 11 corresponds to an example of a metal reflective layer described in the claims, and a phosphoric acid / acetic acid / nitric acid / water (volume ratio of 9: 6: 1: 2) aqueous solution is: This corresponds to an example of a mixed acid composed of phosphoric acid, acetic acid and nitric acid described in the claims.
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). A TFT-LCD type flat display was manufactured by providing a liquid crystal layer on the α-Si TFT active matrix substrate 100. The α-Si TFT active matrix substrate 100 corresponds to an example of the transflective / semi-reflective electrode substrate described in the claims, and the TFT-LCD type flat display is a liquid crystal display device described in the claims. It corresponds to an example.

"Modification Example 1"
In Examples 1 to 3 described above, the example in which the reflective electrode 11 is composed of a metal Mo layer and a metal Al layer is shown. However, the reflective electrode 11 of this example is made of metal Ag instead of the metal Al layer. It is also preferred that it is composed of layers. That is, it is also preferable that the reflective electrode 11 of this example is composed of metal Mo and metal Ag. As described above, even when the metal Ag layer is included instead of the metal Al layer, the reflective electrode 11 of the present modified example 1 has the same effect as the reflective electrode 11 of the above-described examples 1 to 3.

  Moreover, in the said Examples 1-3, although the metal Al layer contained in the reflective electrode 11 showed about the example which consists of pure Al (Al: 100%), this metal Al layer is other than metal Al, It is also preferable to contain a lanthanoid metal such as Nd or a heavy metal such as Co, Ni, Pd, Au, Zr, Pt, or Cu. Similarly, the metal Ag layer preferably contains the lanthanoid metal and heavy metal. Also in this case, the reflective electrode 11 of the present modified example 1 has the same effect as the reflective electrode 11 of the above-described examples 1 to 3.

It is a fragmentary sectional view of the alpha-SiTFT active matrix substrate of a present Example.

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 film 6 α-Si: H (n) film 7 Drain electrode 8 Source electrode 9 Transparent conductive film 10 Transparent resin resist 10a Through Hole 11 Reflective electrode 12 Gate electrode wiring 100 α-Si TFT active matrix substrate

Claims (9)

A transparent substrate;
A transparent conductive layer provided on the transparent substrate, containing indium oxide as a main component, and further containing one or more oxides selected from tungsten oxide, molybdenum oxide, and niobium oxide;
A metal reflective layer provided on the transparent substrate and reflecting external light and electrically connected to the transparent conductive layer;
A transflective / semi-reflective electrode substrate.   [In] / In is the composition ratio of In in the transparent conductive layer containing indium oxide as a main component and further containing one or more oxides selected from tungsten oxide, molybdenum oxide, and niobium oxide. 2. The transflective / semi-reflective electrode substrate according to claim 1, wherein a value of [all metals] is 0.85 to 0.99.   The transflective / semi-reflective electrode substrate according to claim 1 or 2, wherein the metal reflective layer has a layer containing Al or Ag as a component. A transparent substrate;
A transparent conductive layer provided on the transparent substrate, containing indium oxide as a main component, and further containing one or more oxides selected from tungsten oxide, molybdenum oxide, and niobium oxide;
TFT element provided on the transparent substrate;
A metal layer provided on the transparent substrate and electrically connecting the transparent conductive layer and the TFT element;
And a semi-transmissive / semi-reflective electrode substrate, wherein the metal layer has a reflectance of 80% or more.   [In] / In is the composition ratio of In in the transparent conductive layer containing indium oxide as a main component and further containing one or more oxides selected from tungsten oxide, molybdenum oxide, and niobium oxide. 5. The transflective / semi-reflective electrode substrate according to claim 4, wherein the value of [all metals] is 0.85 to 0.99.   6. The transflective / semi-reflective electrode substrate according to claim 4, wherein the metal layer having a reflectance of 80% or more has a layer containing Al or Ag as a component. The transparent conductive layer containing indium oxide as a main component, further containing one or more oxides selected from tungsten oxide, molybdenum oxide, and niobium oxide, and formed on the transparent substrate Etching with an etchant containing oxalic acid;
Etching the metal layer electrically connected to the transparent conductive layer with a mixed acid containing phosphoric acid / acetic acid / nitric acid to form the metal reflective layer;
The method for producing a transflective / semi-reflective electrode substrate according to any one of claims 1 to 3, wherein: The transparent conductive layer comprising indium oxide as a main component, further comprising one or more oxides selected from tungsten oxide, molybdenum oxide, and niobium oxide, and formed on the transparent substrate; Etching with an etchant containing oxalic acid;
Etching the metal layer electrically connected to the transparent conductive layer and the TFT element and having a reflectance of 80% or more with a mixed acid containing phosphoric acid, oxalic acid, and nitric acid;
The method for producing a semi-transmissive / semi-reflective electrode substrate according to any one of claims 4 to 6, comprising: The transflective / semi-reflective electrode substrate according to any one of claims 1 to 6,
A liquid crystal layer driven by the transflective / semi-reflective electrode substrate;
Including a liquid crystal display device.

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