JPH08122822A - Thin film transister substrate and its manufacture and anodic oxidation device - Google Patents

Abstract

PURPOSE: To improve work environment for anodic oxidation by making a gate bus line and a gate electrode of metallic material having low resistance, and forming an anodic oxidation film to cover the gate bus-line and the gate electrode so that a boundary to a gate terminal part may be excellent in control ability. CONSTITUTION: A thin film transistor substrate has a gate bus line 12; a signal bus line 14; a thin film transister 16; a gate terminal part 18; and a gate electrode 20, and the gate bus line 12 and the gate electrode 20 are formed of an aluminum layer 52, and the gate terminal part 18 has structure where aluminum 52, titanium 54 and ITO 56 are overlapped, and the gate bus line 12 and the gate electrode 20 are covered by an aluminum anodic oxidation film 34, and an anodic oxidation film 34 is obtained by carrying out an anodic oxidation treatment as it is covered by the titanium layer 54.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film transistor substrate used in, for example, a liquid crystal display device, a method of manufacturing the thin film transistor substrate, and, for example, an anodizing device suitable for manufacturing the thin film transistor substrate.

[0002]

2. Description of the Related Art In a liquid crystal display device, liquid crystal is enclosed between a pair of substrates, and a light transmission state of the liquid crystal is changed by applying a voltage to perform display. 2. Description of the Related Art Recently, liquid crystal display devices that perform active matrix driving have been actively developed with the increase in size and definition of liquid crystal display devices.
In a liquid crystal display device that performs active matrix driving, one of a pair of substrates is called a thin film transistor substrate, and has gate bus lines, signal bus lines, and thin film transistors provided in a matrix.
The pixel electrode is arranged in a region surrounded by the gate bus line and the signal bus line, and is connected to the thin film transistor. The other substrate is called a color filter substrate, and is provided with a color filter including red, blue, and green portions and a common electrode for each minute region.

In manufacturing a thin film transistor substrate,
The gate bus line and the gate electrode are first formed on the transparent insulating plate. An insulating layer is formed thereon, a semiconductor layer for forming a thin film transistor is formed thereon, and a signal bus line, a drain electrode and a source electrode are further formed thereon. Then, after forming the final protective film, the pixel electrode is formed.

The thin film transistor substrate has an area larger than that of the image display area, has a gate terminal portion (and a drain terminal portion) outside the image display area, and further has a peripheral conductor film outside thereof. The gate terminal portion is at the terminal end portion of the gate bus line and is for connecting to an external wiring such as TAB. A peripheral conductive film is formed in a ring shape around the insulating plate so as to surround the gate bus line, and the peripheral conductive film is connected to all gate terminal portions to prevent a short circuit. The peripheral conductive film is separated from the gate terminal portion when the gate terminal portion is connected to the external wiring.

The gate bus line, the gate electrode, the gate terminal portion, the signal bus line, the drain terminal portion, the drain electrode, the source electrode, etc. are formed of a metal material such as aluminum or titanium. Along with the increase in size and definition of liquid crystal display devices, there is a demand for high-speed driving of thin film transistors, reduction of resistance of gate wiring, uniformization of in-plane luminance distribution, and improvement of manufacturing yield. Therefore, it is preferable that the gate bus line and the gate electrode are made of a metal material having a low resistance, for example, aluminum or an alloy thereof, and an anodic oxide film of the metal material is formed to be a part of the gate insulating film. (For example, Japanese Patent Laid-Open No. 2-85826). In order to perform anodic oxidation, prepare a chemical conversion bath containing the chemical conversion liquid, immerse the insulating plate (thin film transistor substrate) on which the gate bus line, gate electrode, gate terminal portion, etc. are formed in the chemical conversion liquid, and Connect to the power supply anode.
Further, the cathode electrode is immersed in the chemical conversion liquid.

[0006]

In such anodizing treatment, the anodized film is preferably alumina (Al ₂ O ₃ ) in order to form an insulating film having high resistance. For this purpose, it is preferable to use an organic acid having a large molecular weight such as tartaric acid as the chemical conversion liquid. However, when an organic acid having a large molecular weight is used, there is a problem that the concentration cannot be made uniform unless a highly flammable solvent such as ethylene glycol or propylene glycol is used as the solvent.

[0007] In one aspect, the present invention aims to further develop an anodizing process suitable for manufacturing a thin film transistor substrate. Then, it is an object of the present invention to provide an anodizing device that can use pure water as a solvent of a chemical conversion liquid without using a solvent such as highly flammable ethylene glycol or propylene glycol. However, applying an ultrasonic wave in the anodizing treatment is disclosed in, for example, JP-A-62-188215 and JP-A-3-399.
No. 36 and Japanese Patent Laid-Open No. 4-368128.

Further, when the gate bus line and the gate electrode are formed of, for example, aluminum and the aluminum anodic oxide film is used as a part of the gate insulating film, the gate terminal portion located at the end of the gate bus line is anodized. There is a problem that it must be prevented.
That is, since the gate terminal portion is a portion connected to the external wiring, the portion should not be covered with the insulating film.

Therefore, conventionally, when performing the anodization, as shown in FIG. 21, when the gate terminal portion 101 is at the terminal end portion of the gate bus line 100, the gate terminal portion 10 is formed.
A resist 102 was formed on No. 1 and the insulating plate (thin film transistor substrate) was immersed in the chemical conversion liquid with the resist 102 still attached. By doing so, the gate terminal portion 10
No. 1 is not anodized, and only the portion of the gate bus line 100 and the gate electrode without the resist 102 is anodized. FIG. 22 shows the anodic oxide film 103 thus formed. After the anodizing treatment, the resist 102 is peeled off.

However, according to such a method, when patterning the resist 102, the gate bus line 1
00 tends to be over-etched from a portion corresponding to the end portion 104 of the resist 102. If there is over-etching, as shown in FIG. 22, unnecessary anodic oxidation 105 progresses along the interface between the gate terminal portion 101 and the resist 102, and the function of the resist 102 is not sufficiently fulfilled, so that a desired anode is formed. There is a problem that the shape of the oxide film 103 is lost.

Furthermore, since the anodic oxide film 103 is expanded in volume as compared with the original volume of the gate bus line 100,
When such unnecessary anodic oxidation 105 occurs, there is a problem that the resist 102 is lifted up or a downward wedge-shaped anodic oxidation 106 occurs. The wedge-shaped anodic oxidation 106 excessively reduces the conductor cross-sectional area of the gate bus line 100 or the gate terminal portion 101, and there is a possibility that an electrically open portion may be formed.

As another method, there is a method in which the gate bus line and the gate terminal portion are simultaneously anodized, and then the anodic oxide film on the gate terminal portion is etched and removed. However, in this case, it is necessary to perform etching using heavy metal such as chromic acid, and the working environment is not good. As still another method, it is considered that the gate bus line is immersed in the chemical conversion liquid, and the anodic oxidation is performed so that only the gate terminal portion is located above the liquid level of the chemical conversion liquid. However, for this purpose, it is necessary to accurately support the thin film transistor substrate and to accurately maintain the liquid surface level of the chemical conversion liquid, which requires a considerably expensive anodizing device as a whole.

An object of the present invention is to include an anodized film in which the gate bus line and the gate electrode are made of a metal material having a low resistance and which covers the gate bus line and the gate electrode, the anodized film being a boundary with respect to the gate terminal portion. To provide a thin film transistor substrate which can be formed with good controllability, and a method for manufacturing the same. Another object of the present invention is to provide a thin film transistor substrate in which the gate bus line and the gate electrode are made of a metal material having a low resistance such as aluminum, and the gate terminal portion located at the end of the gate bus line has a small contact resistance. And a method for manufacturing the same. Another object of the present invention is to provide an anodizing device which has a good working environment and can be suitably used, for example, in the manufacture of the thin film transistor substrate.

[0014]

A thin film transistor substrate according to the present invention includes a plurality of gate bus lines formed on an insulating plate, and a plurality of signal bus lines arranged to intersect the plurality of gate bus lines. A thin film transistor connected to the gate bus line and the signal bus line,
A gate terminal portion provided at an end of the gate bus line; and a gate electrode integrally extending from the gate bus line and forming a part of the thin film transistor, wherein the gate bus line and the gate electrode have a first A second metal layer overlying the first metal layer and at least partially overlying the first metal layer; and a third metal overlying the second metal layer. Layer, and the gate bus line and the gate electrode are covered with the anodic oxide film of the first metal.

A method of manufacturing a thin film transistor substrate according to the present invention comprises a plurality of gate bus lines formed on an insulating plate, a plurality of signal bus lines arranged to intersect the plurality of gate bus lines, and the gates. A thin film transistor connected to the bus line and the signal bus line; a gate terminal portion provided at an end of the gate bus line; and a gate electrode integrally extending from the gate bus line and forming a part of the thin film transistor. A method of manufacturing a thin film transistor substrate, comprising: forming a first metal layer for forming a gate bus line and a gate electrode on an insulating plate; and selecting a second metal layer in the region of the gate terminal portion. Formed as a mask and using the layer of the second metal as a mask
The metal layer is selectively anodized to form an anodized film covering the gate bus line and the gate electrode, and a thin film transistor is formed in a region including the gate electrode.

The anodizing apparatus according to the present invention comprises a chemical conversion tank for containing a chemical conversion liquid, an anode electrode immersed in the chemical conversion liquid, a cathode electrode immersed in the chemical conversion liquid, and a supersonic wave for applying ultrasonic vibration to the chemical conversion liquid. It is characterized by comprising a sound wave generating means and a solution circulating means for circulating the chemical conversion liquid so that the chemical conversion liquid overflows from a predetermined position of the chemical conversion tank.

[0017]

In the thin film transistor substrate and the method of manufacturing the same described above, anodization is performed with the second metal layer attached to the first metal layer to form an anodized film on the gate bus lines and the gate electrodes. Therefore, the second metal layer acts as a substantial mask in the anodizing process. Prior to the anodizing treatment, the second metal layer is patterned on the first metal layer in accordance with the shape of the gate terminal portion. At the time of patterning, a selective etchant is used. , The first metal layer is not over-etched. Therefore, undesired anodic oxidation at the interface between the second metal layer and the first metal layer, which occurs in the prior art, does not occur, and the anodic oxide film is formed with good controllability.

Further, a second metal layer having a gate terminal portion at least partially overlapped with the first metal layer, and the second metal layer.
Of the first metal, since the anodized film is obtained by anodizing treatment with the second metal layer attached. Even if the layer is made of an easily oxidizable metal material such as aluminum,
The first metal layer does not substantially come into contact with the atmosphere, so that the gate terminal portion having a structure with low contact resistance can be formed.

[0019] In the anodizing apparatus of the present invention, pure water can be used as a solvent for the chemical conversion liquid without using a highly flammable solvent such as ethylene glycol or propylene glycol. Therefore, the anodic oxidation treatment can be used in a clean room without taking any special measures against explosion. Therefore, it can be said that this anodizing device is particularly suitable for manufacturing a thin film transistor substrate manufactured in a clean room and a liquid crystal display device using the same.

[0020]

1 is a sectional view showing a thin film transistor substrate 10 according to a first embodiment of the present invention, which is a sectional view taken along the line I--I of FIG. FIG. 2 is a partial plan view of the thin film transistor substrate 10 of FIG. However, in FIG. 2, some overlapping layers are all shown by solid lines. FIG. 3 is a simplified plan view of the thin film transistor substrate 10 of FIG. 2, showing a state immediately after forming the gate bus lines. FIG. 4 is a diagram showing a configuration of an active matrix when the thin film transistor substrate 10 of FIGS. 1 to 3 is used in a liquid crystal display device.

In FIGS. 1 and 3, the thin film transistor substrate 10 includes a transparent insulating plate 11 such as glass. A gate bus line 12 is formed on the insulating plate 11. The signal bus line 14 is provided as a layer above the gate bus line 12. Further, the thin film transistor 16 is provided adjacent to the gate bus line 12 and the signal bus line 14. A gate terminal portion 18 is provided at the terminal end of the gate bus line 12. The gate terminal portion 18 is TAB
It is for connecting to external wiring such as. In the embodiment, the gate terminal portion 18 is provided only on one side of the insulating plate 11, but the gate terminal portion 18 may be provided on two opposite sides of the insulating plate 11. Further, the signal terminal portion (not shown) can be provided on the side adjacent to the side where the gate terminal portion 18 is provided in the latter manufacturing process.

As shown in FIGS. 3 and 5, the gate bus line 12 is formed integrally with the gate electrode 20 and the storage capacitor electrode 22. The storage capacitor electrode 22 extends on the opposite side of the gate electrode 20 with respect to the gate bus line 12. A peripheral conductor film 24 is formed in an annular shape around the insulating plate 11 so as to surround the gate bus line 12. The peripheral conductor film 24 is connected to the gate terminal portion 18. The peripheral conductor film 24 is separated from the gate terminal portion 18 along the line C in FIG. 5, for example, when the gate terminal portion 18 is connected to an external wiring. Furthermore, the two anodizing terminals 26 are connected to the insulating plate 11.
Is provided so as to be connected to the peripheral conductor film 24 at the edge portion of.

As shown in FIGS. 2 and 4, the gate bus lines 12 and the signal bus lines 14 are arranged so as to intersect each other with an insulating layer interposed therebetween. The thin film transistors 16 are connected to the gate bus lines 12 and the signal bus lines 14 and arranged in a matrix. Each thin film transistor 16
Is a gate electrode 20 extending from the gate bus line 12.
And a drain electrode 28 extending from the signal bus line 14.
And a source electrode 30 and a semiconductor layer 32.

Each of these elements is also shown in FIG.
Further, FIG. 1 shows a gate insulating film including an anodic oxide film 34 made of a metal material of the gate bus line 12 and the gate electrode 20 and an insulating layer 36 made of silicon nitride. Further, a channel protective film 38 is provided on the semiconductor layer 32, and a passivation layer 40 as a final protective film is further provided. In addition, the drain electrode 2
An ohmic contact layer 42 is provided below the electrode 8 and the source electrode 30.

As shown in FIGS. 1, 2 and 4, this embodiment shows a thin film transistor substrate 10 of a liquid crystal display device, in which a pixel electrode 44 is surrounded by a gate bus line 12 and a signal bus line 14. And is connected to the source electrode 30 of the thin film transistor 16. A liquid crystal display device includes the thin film transistor substrate 10, a color filter substrate that faces the thin film transistor substrate, and liquid crystal sealed between these substrates. In FIG. 4, the color filter substrate is 4
6, the liquid crystal is shown by 48. Further, a storage capacitor 50 is formed in parallel with the liquid crystal 48.

As shown in FIGS. 1 and 2, the gate terminal portion 18 is a first extended portion of the gate bus line 12.
Metal layer 52, a second metal layer 54 overlaid on the first metal layer 52, and a third metal overlaid over the second metal layer 54 Layer 56 of
A third metal layer 56 appears on the surface of the substrate and is connected to external wiring. The anodized film 34 starts from the edge portion of the second metal layer 54, and is obtained by anodizing with the second metal layer attached.

In the preferred embodiment, the first metal layer 52 is an aluminum layer, the second metal layer 54 is a titanium layer, and the third metal layer 56 is similar to the pixel electrode 44. It is a layer of ITO. As the first metal layer 52, it is possible to use other valve metals and their alloys that are easily anodized. The second metal layer 54 may be a metal (such as titanium or tantalum) and its alloy that can be continuously deposited directly on the first metal layer 52, for example, in a vacuum chamber. As described above, the gate terminal portion 18 having a structure made of three kinds of metals can be made suitable for connecting to an external wiring having a small contact resistance.

The third metal layer 56 is connected to the second metal layer 54 through the holes 56a formed in the insulating layer 36 and the passivation layer 40. The pixel electrode 44 is connected to the source electrode 30 through a hole 44a provided in the passivation layer 40, and the storage capacitor electrode 22 is connected through the hole 22a (FIG. 2) provided in the insulating layer 36 and the passivation layer 40 to the pixel electrode. Connected to 44.

Next, a method of manufacturing the thin film transistor substrate 10 will be described with reference to FIGS. As shown in FIG. 6, a first metal (aluminum) layer 52 and a second metal (titanium) layer 54 are continuously and entirely deposited on the insulating plate 11 in the sputtering (vacuum). To do.

As shown in FIG. 7, with the stepper, the first metal layer 52 and the second metal layer 54 which are overlapped with each other are provided on the gate bus line 12, the gate terminal portion 18, and the gate electrode 2.
0, the storage capacitor electrode 22, the peripheral conductive film 24, and the anodic oxidation terminal 26 are patterned. This state is shown in FIG. These elements are united. Patterning includes application of resist, exposure, development, etching using resist, and stripping of resist. The etching is performed by RIE using, for example, Cl ₂ + BCl ₃ , and then the corrosion of aluminum is prevented by O ₂ + H ₂ O. Wash after removing the resist.

As shown in FIG. 8, the second metal layer 5
4 at least partially in the region of the gate terminal 18 over the first metal layer 52 (in this case the gate terminal 18 and the peripheral conductor film 24).
Of the first metal layer 5)
2 is exposed in the regions of the gate bus line 12 and the gate electrode 20. Therefore, the resist 6
Use 0. The resist 60 has a shape corresponding to the hatched portion in FIG.

In the embodiment, after the resist 60 is applied on the entire surface, the back surface of the insulating plate 11 is masked with the first metal layer 52 and the second metal layer 54 of the pattern formed as described above. After further exposure (SA exposure) to form a self-aligned pattern, proximity exposure and development are performed to leave the resist 60 only in the regions of the gate terminal portion 18 and the peripheral conductor film 24. Therefore, a dilute HF-based aqueous solution (for example, hydrofluoric nitric acid) is used to exist in the regions of the gate bus line 12, the gate electrode 20, and the storage capacitor electrode 22 other than the regions of the gate terminal portion 18 and the peripheral conductor film 24. The second metal layer 54, titanium, is selectively etched. Instead of the dilute HF-based aqueous solution, titanium may be selectively etched by RIE with a gas such as SF ₆ or CF ₄ .

Next, as shown in FIG. 9, the portion of the first metal layer 52 exposed from the second metal layer 54 is anodized to form the gate bus lines 12, the gate electrodes 20,
An anodic oxide film 34 is formed to cover the storage capacitor electrode 22. Here, for example, the chemical conversion tank shown in FIG. 14 or FIG. 15 is used. This chemical conversion tank contains a specified chemical conversion solution (for example, ammonium tartrate aqueous solution). By applying ultrasonic vibration to the chemical conversion solution and causing the chemical conversion solution to overflow from the bottom to the top of the chemical conversion solution, the concentration of the chemical conversion solution becomes uniform. I am trying to become.

The thin film transistor substrate 10 prepared by the procedure up to FIG. 8 is put in a chemical conversion tank, and the anodizing terminal 26 is set to DC.
The cathode side (not shown) is connected to the plus side of the power source 62 and the minus side of the DC power source 62. A constant DC current is flown, and when the voltage value reaches a predetermined value, the voltage is kept constant, and when the current value falls to a predetermined value, the formation is completed, so that the gate terminal portion 18 and the peripheral conductor film 2 are formed.
An Al ₂ O ₃ anodic oxide film 34 is formed on the gate bus lines 12, the gate electrodes 20, and the storage capacitor electrodes 22 other than 4. The anodizing terminal 26 is not anodized because it is not immersed in the chemical conversion liquid. After that, the substrate is washed with QDR to remove the chemical conversion liquid on the substrate.

After that, the resist 60 is stripped with a resist stripping solution (for example, a chemical solution containing NNT or triamine as a main component) that does not easily corrode the aluminum of the anodizing terminal 26, and then the substrate is washed again by QDR and pulled up. It is dried by a predetermined drying means such as drying, spin drying or air knife drying. After that, the substrate is annealed, and as shown in FIG. 10, a silicon nitride film (insulating layer 36), an amorphous silicon film (semiconductor layer 32), and a silicon nitride film (channel protection layer 38) are continuously formed by plasma CVD. To film. The channel protective layer 38 is formed into a predetermined shape through the steps of resist application, SA exposure and stepper exposure, development, etching, and resist stripping. At this time, the semiconductor layer 32 still remains entirely.

Next, the ohmic contact layer (n ⁺ a-S
i) After forming 42 by plasma CVD, titanium / aluminum / titanium is continuously formed by sputtering, and the signal bus line 14, drain electrode 28, and source electrode 30 are patterned by a stepper. When etching is performed by RIE with Cl ₂ + BCl ₃ , the ohmic contact layer 42, the semiconductor layer 32, and the titanium / aluminum / titanium layer (the signal bus line 14, the drain electrode 28, and the source electrode 30) have predetermined shapes. Then O ₂ +
Take measures against corrosion of aluminum with H ₂ O.

Next, a silicon nitride film is formed as the passivation film 40 by plasma CVD, and then the holes 22 are formed.
patterning for opening a, 44a with a stepper,
Patterning for forming the holes 56a is performed by proximity exposure, respectively, and RIE is performed with SF ₆ or CF ₄ .
Then, the silicon nitride film (insulating film 36, passivation film 40) is etched to form holes 22a, 44a and 56a. Then, after forming an ITO film on the substrate, the gate terminal portion 18, the signal terminal portion (not shown) and the pixel electrode 44 are patterned by a stepper, and the oxalic acid aqueous solution is used to form the ITO.
Are etched to form the gate terminal portion 18, the signal terminal portion (not shown) and the pixel electrode 44. Finally, by finally separating the peripheral conductor film 24 along the cutting line C of FIG. 5, the thin film transistor substrate 1 shown in FIGS.
0 is obtained.

11 to 13 show anodizing treatment,
It is a figure which shows the gate terminal part 18 after peeling the resist 60. The anodized film 34 is obtained by anodizing the first metal layer 52 with the second metal layer 54 attached. In the prior art described with reference to FIGS. 21 and 22, the aluminum gate bus line 100 is used.
Since the anodic oxidation is performed with the resist 102 attached on the top surface, if the gate bus line 100 is over-etched 104, the gate terminal portion 101 and the resist 10 are not formed.
There is a problem in that unnecessary anodic oxidation 105 and wedge-shaped anodic oxidation 106 progress along the interface with 2 and the desired shape of the anodic oxide film 103 is lost.

In the present invention, since the first metal layer 52 and the second metal layer 54 are continuously formed, the gap between the first metal layer 52 and the second metal layer 54 is reduced. Has strong adhesion. In addition, the second metal layer 54 is etched using an etchant that is selective to the first metal layer 52, so that the first metal layer 52 underneath the second metal layer 54 is etched. Over etching does not occur.

For this reason, the formed anodic oxide film 34 is formed into an accurate contour shape along the edge of the second metal layer 54 patterned into a predetermined shape, that is, controlled to have an intended shape. Formed well. The anodized film 34 is substantially absent at the interface between the first metal layer 52 and the second metal layer 54. Therefore, the conductivity of the gate bus line 12 and the gate terminal portion 18 is not adversely affected. Further, the anodic oxide film 34 is slightly expanded more than the outer shape of the original first metal layer 52, and the gate terminal portion 18 is formed.
It is designed to wrap around. Anodized film 34
Wraps the gate bus line 12, the gate electrode 20, and the storage capacitor electrode 22 properly, and even if a high temperature (for example, 300 ° C.) is applied when the insulating layer 36 is formed later, the gate bus line 12 made of aluminum, the gate Electrode 2
0, and the storage capacitor electrode 22 is not attacked.

FIG. 14 is a diagram showing an example of an anodizing device used in the anodizing step of FIG. The anodizing device includes a chemical conversion bath 70. The chemical conversion tank 70 contains a predetermined chemical conversion liquid 72 (for example, a citric acid aqueous solution or a tartaric acid aqueous solution with ammonia water added to adjust the pH). That is, in this example, water is used as the solvent of the chemical conversion liquid 72,
It can be used in a uniform concentration. Water can be used as the solvent of the chemical conversion liquid 72, because the concentration can be made uniform by subjecting the chemical conversion liquid 72 to ultrasonic vibration and causing the chemical conversion liquid to overflow from the bottom to the top as described below. Is. In order to make the concentration of the organic chemical conversion liquid uniform, the vibration of the chemical conversion liquid of ultrasonic wave of 42 KHz or more is used.
It has been found that it is preferable to give it to 2. For this reason,
An ultrasonic wave generator 74 is attached to the outer wall of the chemical conversion tank 70. The ultrasonic generator 74 includes an ultrasonic diaphragm having a known structure. The ultrasonic wave generator 74 can be attached to the side wall or the bottom wall of the chemical conversion tank 70.

The circulation device for the chemical conversion liquid 72 is constructed as follows. A chemical conversion liquid inlet 70a is provided on the bottom wall of the chemical conversion tank 70, and the top of the chemical conversion tank 70 is open. A storage tank 76 is provided separately from the chemical conversion tank 70, and an overflow tank 78 is attached around the chemical conversion tank 70.
Therefore, the chemical conversion liquid 72 is pumped from the storage tank 76 to the pump 80,
The chemical conversion liquid inlet 70a of the chemical conversion tank 70 through the filter 82
And overflows from the top of the chemical conversion tank 70,
Return to the storage tank 76 through the overflow tank 78. The pump 80 is controlled by the controller 80a. Further, a rectifying plate 80 is provided near a lower portion in the chemical conversion tank 70, and the chemical conversion liquid 72 supplied to the chemical conversion liquid inlet 70a of the chemical conversion tank 70 becomes a laminar flow by the flow regulating plate 80, thereby disturbing the turbulence in the chemical conversion tank 70. It reaches the top of the chemical conversion tank 70 while being suppressed as much as possible, and overflows while suppressing the fluctuation of the liquid surface.

As described above, the thin film transistor substrate 10 is placed in the chemical conversion bath 70, and is connected to the positive side of the DC power source so that the anodizing terminal 26 is located on the liquid surface. Further, the cathode electrode 82 is put in the chemical conversion bath 70, and DC
Connected to the negative side of the power supply. Thus, the gate bus line 1 other than the gate terminal portion 18 and the peripheral conductor film 24 is formed.
2, Al ₂ O for the gate electrode 20 and the storage capacitor electrode 22
An anodic oxide film 34 of ₃ is formed.

FIG. 15 is a diagram showing another example of the anodizing device. The anodizing device includes a chemical conversion bath 70. The chemical conversion tank 70 contains a predetermined chemical conversion liquid 72. Also in this example, water is used as the solvent of the chemical conversion liquid 72, and the chemical conversion liquid 72 can be used in a uniform concentration state. Therefore, ultrasonic vibration is applied to the chemical conversion liquid 72, and the chemical conversion liquid overflows from the bottom to the top of the chemical conversion tank.

A storage tank 76 and an overflow tank 78 are provided as means for circulating the chemical conversion liquid 72.
A chemical conversion liquid inlet 70a is provided on the bottom wall of the chemical conversion tank 70, the top of the chemical conversion tank 70 is opened, and the chemical conversion liquid 72 is stored in a storage tank 76.
Is supplied to the chemical conversion liquid inlet 70a of the chemical conversion tank 70 through the pump 80 and the filter 82, overflows from the top of the chemical conversion tank 70, and returns to the storage tank 76 through the overflow tank 78. The pump 80 is controlled by the controller 80a. Further, a current plate 80 is provided near the lower part in the chemical conversion tank 70.

In this embodiment, the storage tank 76 is suitably supported in the outer tub 84 to float on water. The ultrasonic wave generation device 74 is attached to the outer tank 84, and applies ultrasonic vibration to the chemical conversion liquid 72 via the water in the outer tank 84. The outer tub 84 has a water inlet 84a and a water outlet 84b, and water is circulated and supplied. An ultrasonic wave generator 7 is provided with a water level sensor (not shown).
It is designed so as to prevent the empty operation of No. 4. 76a, 84
Reference characters c are lids of the storage tank 76 and the outer tank 84, respectively.

Further, inside the storage tank 76, the chemical conversion liquid 72 is blown upward from the end of the return pipe 86 by 5 to 30 degrees with respect to the horizontal, and circulates inside the storage tank 76. It is like this.
The storage tank 76 is also provided with a chemical liquid level sensor and a temperature sensor (not shown).

Second Embodiment FIGS. 16 to 20 are views showing another embodiment of the thin film transistor substrate 10. This embodiment is substantially similar to the embodiment of FIGS. 1-13 except for the formation of the first metal layer 52 and the second metal layer 54. Therefore, here, the formation of the first metal layer 52 and the second metal layer 54 will be mainly described.

The thin film transistor substrate 10 has a gate bus line 12, a signal bus line 14, a thin film transistor 16 and a pixel electrode 44 formed on an insulating plate 11. The gate bus line 12 is the gate electrode 20.
And the storage capacitor electrode 22, the first metal layer 52 is made of aluminum. Gate bus line 1
The first metal layer 52 forming the second
It ends at the part that took a little. Gate terminal 18
In which the second metal layer 54 is the first metal layer 52.
A third metal layer 56 formed partially overlapping the edges of the
Are further overlaid on the second metal layer 54. A third metal layer 56 appears on the surface of the substrate and is connected to external wiring. The first metal layer 52 is an aluminum layer, the second metal layer 54 is a titanium or tantalum layer, and the third metal layer 56 is an ITO layer like the pixel electrode 44. Alloys of these metals can be used.

FIG. 17 is a view showing a region of the first metal layer 52 which is initially formed, and includes the gate bus line 12, the gate electrode 20, the storage capacitor electrode 22, and the anodizing terminal 26. 18 and 19 are views showing the region of the second metal layer 54 to be formed thereafter, which includes the gate terminal portion 18 and the peripheral conductor film 26. Second metal layer 54
Are partially overlapped with the first metal layer 52 forming the gate bus line 12 and the peripheral conductor film 26.

FIG. 20 is a diagram showing a method of manufacturing the thin film transistor substrate 10. As shown in (A), a first metal (aluminum) layer 52 is formed on the insulating plate 11 and patterned into a predetermined shape. Then, as shown in (B), a second metal (titanium) layer 5
4 is deposited on the patterned first metal layer 52. Then, as shown in (C), a resist 60 is applied, and after exposure and development, the second metal layer 54 is etched. Then, as shown in (D), anodic oxidation is performed with the resist 60 left, and an anodic oxide film 34 is formed around the first metal layer 52. The procedure thereafter is similar to that of the previous embodiment. However, in this case, since there is a time interval between the first metal layer forming step and the second metal layer forming step, the first metal layer and the second metal layer are different from each other as compared with the first embodiment. The interface is not clean.

[0052]

As described above, according to the thin film transistor substrate and the method of manufacturing the same of the present invention, the formation of the anodic oxide film (the boundary between the anodized portion and the non-anodized portion) around the gate terminal portion can be controlled with good controllability. Since it can be carried out, electrical defects around the gate terminal portion are eliminated, and the interface between the first and second metals is maintained in a clean state,
After that, the gate terminal portion having a low contact resistance can be formed together with the connected third metal layer. Further, according to the anodizing apparatus of the present invention, since the chemical conversion solution can be made to have a uniform concentration as an aqueous solution, it is not necessary to use a solvent which has an environmental problem as in the conventional case, and a special waste liquid treatment facility is provided. You don't need it and you can improve your working environment.

[Brief description of drawings]

1 is a cross-sectional view taken along line I-I of FIG. 2, showing a thin film transistor substrate according to a first embodiment of the present invention.

FIG. 2 is a partial plan view of the substrate of FIG.

3 is a simplified overall plan view of the substrate of FIG. 2 showing the gate bus lines immediately after formation.

FIG. 4 is a diagram showing a configuration of an active matrix.

5 is a plan view showing a part of the substrate of FIG.

FIG. 6 is a diagram showing a step of depositing layers of first and second metals.

FIG. 7 is a diagram showing a step of patterning first and second metal layers.

FIG. 8 is a view showing a step of further patterning a second metal layer.

FIG. 9 is a diagram showing an anodic oxidation process.

FIG. 10 is a cross-sectional view showing a process of forming a semiconductor layer.

FIG. 11 is a plan view showing a gate terminal portion of a substrate subjected to anodization.

12 is a cross-sectional view taken along the line XII-XII in FIG.

FIG. 13 is a cross-sectional view taken along the line XIII-XIII in FIG.

FIG. 14 is a diagram showing an example of an anodizing device.

FIG. 15 is a diagram showing another example of the anodizing device.

FIG. 16 is a cross-sectional view showing another embodiment of the thin film transistor substrate.

FIG. 17 is a diagram illustrating a region of a first metal layer.

FIG. 18 is a diagram illustrating regions of first and second metal layers.

FIG. 19 is a partially enlarged view of FIG. 18.

FIG. 20 is a diagram showing a manufacturing process of the substrate of FIG. 16;

FIG. 21 is a diagram illustrating a conventional technique.

FIG. 22 is a diagram illustrating a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Substrate 11 ... Insulating plate 12 ... Gate bus line 14 ... Signal bus line 16 ... Thin film transistor 18 ... Gate terminal part 20 ... Gate electrode 34 ... Anodized film 36 ... Insulating film 52, 54, 56 ... Metal layer 70 ... Chemical formation Layer 74 ... Ultrasonic wave generation means 76 ... Storage tank 78 ... Overflow tank 80 ... Pump

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hideaki Takizawa Inventor Hideaki Takizawa 1015 Kamiodanaka, Nakahara-ku, Kawasaki, Kanagawa, Fujitsu Limited (72) Inventor Makoto Tachibaki 1015 Kamedota, Nakahara-ku, Kawasaki, Kanagawa Prefecture, Fujitsu Limited

Claims (24)

[Claims] 1. A plurality of gate bus lines (12) formed on an insulating plate (11), and a plurality of signal bus lines (14) arranged so as to intersect with the plurality of gate bus lines.
A thin film transistor (16) connected to the gate bus line and the signal bus line, a gate terminal portion (18) provided at an end of the gate bus line, and extending integrally from the gate bus line and A gate electrode (20) forming a part of a thin film transistor, the gate bus line (12) and the gate electrode (20)
Is formed of a first metal layer (52), and the gate terminal portion (18) includes a second metal layer (54) at least partially overlying the first metal layer and the second metal layer (54). Two
A third metal layer (56) overlying the first metal layer, the gate bus line (12) and the gate electrode (20)
Is covered with an anodic oxide film (34) of the first metal. 2. The thin film transistor substrate according to claim 1, wherein the layer of the first metal is made of one of aluminum and an alloy containing aluminum as a main component. 3. The second metal layer is titanium, tantalum,
3. The thin film transistor substrate according to claim 2, wherein the thin film transistor substrate comprises one of alloys containing these metals as a main component. 4. The thin film transistor substrate according to claim 1, wherein a storage capacitor electrode (22) is provided integrally with the gate bus line and the gate electrode. 5. A layer of said second metal is formed at least partially overlying a layer of said first metal, said first layer of metal
The thin film transistor substrate according to claim 1, wherein the anodic oxide film is formed on a portion of the metal layer which does not overlap with the second metal layer. 6. A peripheral conductive film (24) is annularly formed on the peripheral portion of the insulating plate so as to surround the gate bus line,
The thin film transistor substrate according to claim 1, wherein the peripheral conductive film is connected to the gate terminal portion and can be separated from the gate terminal portion when the gate terminal portion is connected to an external wiring. . 7. The thin film transistor substrate according to claim 6, wherein two anodizing terminals (26) are provided at the edge of the insulating plate so as to be connected to the peripheral conductive film. . 8. The thin film transistor includes a gate electrode, a gate insulating layer formed of the anodized film and a second insulating film, a semiconductor layer formed on the gate insulating layer, and the signal bus line. 2. The third insulating film, which comprises a drain electrode connected to the semiconductor layer and a source electrode connected to the semiconductor layer, and further provided with a third insulating film covering the thin film transistor. Thin film transistor substrate. 9. The third insulating film is formed so as to cover the second metal in the gate terminal portion, and the third metal passes through a hole provided in the third insulating film to form the third insulating film. 9. The thin film transistor substrate according to claim 8, wherein the thin film transistor substrate is connected to the second metal. 10. The thin film transistor substrate is used in a liquid crystal display device and includes a pixel electrode, the pixel electrode being the third electrode.
Connected to the source electrode through a hole provided in the insulating film of
10. The thin film transistor substrate according to claim 9, wherein the pixel electrode and the third metal layer are formed of the same material at the same time. 11. A plurality of gate bus lines (12) formed on an insulating plate (11), and a plurality of signal bus lines (1) arranged so as to intersect the plurality of gate bus lines.
4), a thin film transistor (16) connected to the gate bus line and the signal bus line, a gate terminal portion (18) provided at an end of the gate bus line, and the gate bus line (12) A method for manufacturing a thin film transistor substrate, comprising: a gate electrode (20) that extends horizontally and becomes a part of the thin film transistor (16), the first method for forming a gate bus line and a gate electrode.
A metal layer (52) of the second metal is formed on the insulating plate (11), and a second metal layer (54) is selectively formed in the region of the gate terminal portion (18). Using the layer (54) as a mask, the first metal layer (52) is selectively anodized to form an anodized film (34) covering the gate bus line and the gate electrode. A method of manufacturing a thin film transistor substrate, comprising forming a thin film transistor (16) in a region including the thin film transistor. 12. An insulating film (36, 40) is formed so as to cover the thin film transistor and the region of the gate terminal portion, and a hole is formed in the region of the gate terminal portion of the insulating film to form a first layer on the insulating film. Forming a third metal layer (56) and passing the third metal layer through the holes to the second metal layer (54)
To expose the third metal layer (56) to the surface,
The method of manufacturing a thin film transistor substrate according to claim 11, wherein the gate terminal portion (18) connected to an external wiring is formed. 13. The step of forming a first metal layer comprises the steps of depositing the first metal layer over an insulating plate, and forming the first metal layer on the gate bus line and the gate electrode. , And a first according to at least a part of the gate terminal portion
And forming a second metal layer on the insulating plate, the second metal layer is formed on the entire surface of the insulating plate. The step of depositing the first metal layer in a predetermined shape that is the same as the predetermined shape of the first metal layer, and the second metal layer remaining at least partially in the region of the gate terminal portion and having the first shape. Forming a second metal layer in a second predetermined shape such that the metal layer is exposed in the regions of the gate bus line and the gate electrode, and forming the first metal layer in the predetermined shape. The method of manufacturing a thin film transistor substrate according to claim 11, wherein the step and the step of forming the second metal layer in a predetermined shape are performed at the same time. 14. The method according to claim 13, wherein a mask is used in the step of forming the second metal layer into the second predetermined shape, and the anodic oxidation step is performed with the mask attached. A method for manufacturing the thin film transistor substrate described. 15. The step of forming a first metal layer comprises the steps of depositing the first metal layer over the insulating plate, and forming the first metal layer on the gate bus line and the gate electrode. And forming a second metal layer over the entire surface of the first metal layer having a predetermined shape. A second metal layer at least partially overlaps the first metal layer and remains at least partially in the region of the gate terminal portion, and the first metal layer is a gate bus. 12. The method of manufacturing a thin film transistor substrate according to claim 11, further comprising the step of forming a second metal layer in a second predetermined shape so as to be exposed in the regions of the line and the gate electrode. 16. The method according to claim 14, wherein a mask is used in the step of forming the second metal layer into the second predetermined shape, and the anodic oxidation step is performed with the mask attached. A method for manufacturing the thin film transistor substrate described. 17. The method of manufacturing a thin film transistor substrate according to claim 11, wherein in the step of anodizing the layer of the first metal, ultrasonic waves are applied to the anodizing chemical solution. 18. The method of manufacturing a thin film transistor substrate according to claim 11, wherein water is used as a chemical conversion liquid for anodizing in the step of anodizing the first metal layer. 19. When forming a thin film transistor after the anodic oxidation step, an insulating film is further formed on the anodic oxide film, a semiconductor film is formed on the insulating film, and the semiconductor film is formed on the semiconductor film. The method of manufacturing a thin film transistor substrate according to claim 11, comprising a step of forming a signal bus line, a drain electrode and a source electrode. 20. In the step of forming the first metal layer, the insulating plate is formed of the same material as the first metal layer so as to surround the gate bus line and be connected to the gate terminal portion. The method of manufacturing a thin film transistor substrate according to claim 11, wherein a peripheral conductor film is formed in an annular shape on the peripheral portion of the. 21. The method of manufacturing a thin film transistor substrate according to claim 20, wherein the peripheral conductor film is separated from the gate terminal portion when the gate terminal portion is connected to an external wiring. 22. A chemical conversion tank (70) containing a chemical conversion liquid,
An anode electrode (10) immersed in the chemical conversion liquid, a cathode electrode (82) immersed in the chemical conversion liquid, an ultrasonic wave generation means (74) for applying ultrasonic vibration to the chemical conversion liquid, and the chemical conversion liquid in the chemical conversion tank. An anodizing device comprising a solution circulating means (76, 78, 80) for circulating the chemical conversion liquid so as to overflow from a predetermined position. 23. The anodizing device according to claim 22, wherein the ultrasonic wave generating means is attached to the chemical conversion tank. 24. The anodizing apparatus according to claim 22, wherein the ultrasonic wave generating means is attached to the solution circulating means.