JP2003073860A - Multilayer-type transparent electroconductive film, and method for patterning the film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology for patterning a multilayer-type transparent electroconductive film. SOLUTION: The transparent electroconductive film has a multilayer structure comprising a first ITO film, a metallic thin film, and a second ITO film, and is characterized by not exposing the film to an atmosphere of 300 deg.C or higher, through start of formation to etching of the transparent film, to make the first and the second ITO films keep an amorphous structure. The ITO film having the amorphous structure, and a crystallized ITO film are respectively shown in the Fig. 10 (a, b) and (c) in the specification. Then, the first and the second ITO films having the amorphous structure can be etched by oxalic acid.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a manufacturing process of an organic EL device, and more particularly to a laminated transparent conductive film forming an anode electrode film of the organic EL device and a patterning method thereof.

[0002]

2. Description of the Related Art Conventionally, a polycrystalline ITO film (ITO: transparent conductive film) has been used as an anode electrode film of an organic EL device.
Indium tin oxide) is used.

However, since the resistance value of the polycrystalline ITO film is large, there is a problem that when the panel size becomes large, unevenness in brightness occurs in the panel surface due to voltage drop.

In order to solve this, a metal thin film and ITO
A technique has been proposed in which films are laminated to form a laminated transparent conductive film. This laminated transparent conductive film has excellent surface smoothness and low resistance, and is therefore regarded as a promising anode electrode for organic EL devices.

However, when the ITO film in the laminated transparent conductive film is formed without heating, the adhesion between the ITO film and the metal thin film or the adhesion between the ITO film and the resist film. However, there is a problem that film peeling and side etching during patterning by wet etching are severe.

On the other hand, although the heat-treated ITO film improves the adhesion, it can be etched only by a strong acid such as salt iron (diiron chloride + hydrochloric acid) or chloronitric acid (HCl + HNO ₃ ). The etching rate is significantly different from that of the thin film, and it becomes difficult to perform uniform etching.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned etching characteristics, and to provide a technique for forming a good pattern of a laminated transparent conductive film.

[0008]

In order to solve the above problems, the invention according to claim 1 provides a first ITO film formed on a substrate and a transparent film formed on the surface of the first ITO film. Metal thin film and a second I formed on the surface of the metal thin film
A laminated transparent conductive film having a TO film, wherein the first and second ITO films and the metal thin film are formed at a temperature of less than 300 ° C.
The invention according to claim 2 is the transparent conductive film according to claim 1, wherein the first and second ITO films and the metal thin film are formed at room temperature. The invention according to claim 3 is the transparent conductive film according to claim 1 or 2, wherein the transparent conductive film is annealed at a temperature of less than 300 ° C. The invention according to claim 4 is the transparent conductive film according to any one of claims 1 to 3, wherein the metal thin film contains silver as a main component. According to the invention of claim 5, a first ITO film formed on a substrate, a transparent metal thin film formed on the surface of the first ITO film, and a second metal film formed on the surface of the metal thin film.
The first and second ITO films and the metal thin film are patterned by a patterning method of patterning a laminated transparent conductive film formed at a temperature of less than 300 ° C. The resist film is formed on the second ITO film.
It is a patterning method which is formed on a film and at least the second ITO film is etched with a first etching solution containing oxalic acid. The invention according to claim 6 is characterized in that the metal thin film is composed of a silver alloy thin film containing silver as a main component, and the metal thin film is etched with a second etching liquid in which phosphoric acid and nitric acid are mixed. The patterning method according to claim 5. The invention according to claim 7 provides the first I
The patterning method according to claim 5 or 6, wherein the TO film is etched with the first etching solution, wherein the ITO residue is removed by hydrochloric acid or sulfuric acid after the etching of the first ITO film. Patterning method.

The present invention is formed as described above, and the first and second ITO films forming the laminated transparent conductive film are
From the formation to the patterning, the temperature is not raised to 300 ° C. or higher. Therefore, I
The crystallization of TO does not proceed, and the first and second ITO films can be etched with the first etching liquid containing oxalic acid as a main component.

Annealing before the resist patterning etching is performed with the resist film formed on the surface of the second ITO film,
This is for improving the adhesiveness with the second ITO film, so that it is heated only to a temperature lower than 300 ° C. and crystallization does not proceed.

Further, in the transparent conductive film having the laminated structure, the first and second ITO films are in contact with the metal thin film disposed in the middle thereof, and the metal thin film is being annealed.
It is thought to suppress the rearrangement of atoms in the film.

As a result, since the first and second ITO films are composed of fine crystals, it is presumed that the first and second ITO films can be etched with the first etching solution of a weak acid such as oxalic acid.

The metal thin film containing silver as a main component is the first
In contrast to the first etching solution, the second etching solution etches the metal thin film containing silver as a main component and does not etch the ITO film because the first and second ITO films do not etch with the second etching solution. By etching the metal thin film located in the middle of, the patterning of the laminated transparent conductive film becomes possible.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference numeral 10 in FIG. 9 shows a sputtering film forming apparatus for a laminated transparent conductive film to which the present invention can be applied. The sputtering film forming apparatus 10 includes a first to a third sputtering chamber 1
It has 1, 12, and 13.

The sputtering film forming apparatus 10 is an in-line type film forming apparatus, and includes first to third sputtering chambers 11 to 1.
3 are arranged on a straight line. The first sputtering chamber 11 and the second sputtering chamber 12 are partitioned by a valve 14, and similarly, the second sputtering chamber 12 and the third sputtering chamber 13 are partitioned by a valve 15.

The first sputtering chamber 11 is a film forming chamber for forming a first ITO film on the surface of an object to be formed, and the second sputtering chamber 12 is for forming a metal thin film on the formed ITO film surface. It is a film forming chamber. The third sputtering chamber 13 is a film forming chamber in which an ITO film is further formed on the surface of the metal thin film.

The first to third sputtering chambers 11 to 13 are respectively connected to a vacuum exhaust system, and valves 14 and 15 are provided.
In the closed state, the sputtering chambers 11 to 13 can be individually evacuated.

In the first to third sputtering chambers 11 to 13,
The first to third gas introduction systems 31 to 33 are connected.

The first to third gas introduction systems 31 to 33 are each adapted to be able to introduce Ar gas as a sputtering gas, and further, the first gas introduction system 31 and the third gas introduction system 33. Is capable of introducing a reactive gas in addition to the sputtering gas. Here, O ₂ gas and H ₂ O gas are used as the reactive gas.

Inside the first to third sputtering chambers 11 to 13, first to third cathode electrodes 36 to 38 are arranged, respectively.

The first to third targets 16 to 18 are mounted on the first to third cathode electrodes 36 to 38, respectively.

The first target 16 and the third target 18 are each composed of an ITO plate having a composition of In ₂ O ₃ -10 wt% SnO ₂ , and the second target 1
Reference numeral 7 is a silver alloy plate having a composition containing silver as a main component and 2 wt% gold and 2 wt% copper.

Further, the first to third cathode electrodes 36 to 3
The first to third DC power supplies 22 to 24 are connected to each of the eight, and the first to third DC power supplies 22 to 24 are individually operated to operate the first to third cathode electrodes 11 to 13. It is configured such that a DC voltage can be applied to each.

A process of forming an ITO film having a laminated structure using this sputtering film forming apparatus 10 will be described.

Here, the first to third sputtering chambers 11 to 1 are used.
The inside of 3 is evacuated, the glass substrate 26 is attached to the carrier 25, and the glass substrate 26 is held together with the carrier 25 in the first sputtering chamber 11 while maintaining the vacuum atmosphere inside each of the sputtering chambers 11 to 13. Bring in.

The first to third targets 16 to 18 are arranged on the bottom surface inside the first to third sputtering chambers 11 to 13, the glass substrate 26 is carried in near the ceiling, and the film forming surface thereof is formed. Can be turned downwards.

Next, the first gas introduction system 31 introduces the sputtering gas (Ar gas) and the reactive gas (O ₂ gas, H ₂ O gas) into the first sputtering chamber 11 while controlling the flow rates. , The internal pressure of the first sputter chamber 11 is 0.
When stabilized at 67 Pa, the first cathode electrode 36
When a DC voltage is applied to the first target 16 to generate plasma of sputtering gas and plasma of reactive gas in the vicinity of the surface of the first target 16, the first target 16 is sputtered.

When the carrier 25 is horizontally moved in this state, the glass substrate 26 moves above the first target 16 and the first ITO film grows on the surface of the glass substrate 26.

When the first ITO film was grown, and when the metal thin film and the second ITO film described later were grown, the glass substrate 26 was not heated and the thin film was grown at a low temperature of about room temperature. .

After the glass substrate 26 has passed above the first target 16 and the first ITO film has been formed to a predetermined thickness on the surface thereof, the first sputtering chamber 11 and the second sputtering chamber 12 are formed. The valve 14 between and is moved, the carrier 25 is moved, the glass substrate 26 is carried into the second sputtering chamber 12 together with the carrier 25, and the valve 14 is closed.

The second gas introduction system 32 introduces the sputtering gas into the second sputtering chamber 12 while controlling the flow rate, and when a pressure of 0.27 Pa is reached, a DC voltage is applied to the second cathode electrode 37. When applied and plasma of the sputtering gas is generated in the vicinity of the surface of the second target 17, the sputtering of the second target 17 is started.

When the carrier 25 is horizontally moved in this state, the glass substrate 26 moves above the second target 17 and a metal thin film grows on the surface of the first ITO film. Here, the sputtering rate and the glass substrate 26
Is adjusted so that the transparency of the metal thin film is maintained.

Then, after the glass substrate 26 passes above the second target 17 and a transparent metal thin film is formed on the surface of the first ITO film, the second sputtering chamber 12 and the third sputtering chamber 12 are formed. 13 and the valve 15 is opened, and the carrier 25 is moved.
6 is loaded into the third sputtering chamber 13, and the valve 15 is closed.

Inside the third sputtering chamber 13, the first sputtering chamber 13
The third target 18 is sputtered under the same conditions as those in the sputtering chamber 11 to form a second ITO film on the surface of the metal thin film. And the first IT
The glass substrate 26 having the transparent conductive film in which the O film, the metal thin film, and the second ITO film are laminated in this order is taken out from the inside of the sputtering film forming apparatus 10.

Reference numeral 40 in FIG. 1 indicates a laminated transparent conductive film on the glass substrate 26.
Is the first ITO film 41 having a film thickness of 40 nm and a film thickness of 10 n
It is composed of a metal thin film 42 of m and a second ITO film 43 having a film thickness of 400 nm.

Next, the glass substrate 26 taken out from the sputtering film forming apparatus 10 was placed in an oven, and the transparent conductive film 40 was annealed under the heating condition of 200 ° C. for 1 hour.

After the annealing treatment, a resist solution (manufactured by Tokyo Ohka Kogyo Co., Ltd .: OFPR-8) was formed on the surface of the second ITO film 43.
00) was applied, and a resist film having a predetermined pattern was formed by exposure and development.

Reference numeral 45 in FIG. 2 shows the resist film, and the resist film 45 has the second ITO film 4 on the bottom surface.
3 has an opening 46 exposed.

Next, the glass substrate 26 in this state is placed at 140
After heating to 0 ° C. to improve the adhesion between the resist film 45 and the second ITO film 43, the glass substrate 26 is immersed in the first etching solution for etching the ITO film, and the opening 46 is formed.
Etching the second ITO film 43 exposed on the bottom surface of
The second ITO film 43 is patterned.

This first etching solution is a commercially available oxalic acid solution.
(ITO-05N manufactured by Kanto Chemical Co., Inc.), and ITO is the first
While the silver alloy thin film is not dissolved, the second ITO film 43 is etched, and when the metal thin film 42 is exposed, the etching in the film thickness direction is stopped.

FIG. 3 shows this state, in which the metal thin film 42 is exposed at the bottom of the opening 46, and the second ITO film 43 is formed.
Are patterned according to the pattern of the resist film 45. Here, the surface of the metal thin film 42 was exposed by immersion for 100 seconds.

Next, the substrate 26 on which the second ITO film 43 is patterned is dipped in a second etching solution for etching a silver alloy. The second etching solution is a mixed acid of phosphoric acid and nitric acid (phosphoric acid: nitric acid: water = 4: 1: 5). The second etching liquid etches the metal thin film 42 exposed on the bottom surface of the opening 46.

Since the silver alloy is dissolved in the second etching solution, but the ITO film is not dissolved, as shown in FIG. 4, the film thickness is obtained when the first ITO film 41 is exposed at the bottom of the opening 46. Directional etching stops. Here, the first ITO film 41 was exposed by immersion for 10 seconds.

Next, when the glass substrate 26 is immersed in the first etching solution, the first ITO film 41 exposed on the bottom surface of the opening 46 is etched, and the first IT film is formed.
The O film 41 is patterned.

Since the glass substrate 26 is not etched by the first etching solution, the etching in the film thickness direction is completed when the surface of the glass substrate 26 is exposed at the bottom of the opening 46. Here, the surface of the glass substrate 26 was exposed at the bottom surface of the opening 46 by immersion for 50 seconds.

Then, the substrate 26 in that state is dipped in a resist stripping solution such as acetone to remove the resist film 45. FIG. 6 shows the glass substrate 26 and the transparent conductive film 40 in that state, and the transparent conductive film 40 has an opening 47 having the same planar shape as the resist film 45.

The shape of the opening 47 of the transparent conductive film 40 is SEM.
As a result, it was observed that there was no side etching and the shape was sharp (see FIG. 11).

Under the same film forming conditions as the transparent conductive film 40, the transparent conductive film is formed by changing the film thicknesses of the first ITO film 41, the metal thin film 42, and the second ITO film 43. When an opening is formed by using the etching solution of No. 2 and the above-mentioned second etching solution, the first ITO film has a thickness of 10 nm or more and 200 n or more.
m or less, the metal thin film has a thickness in the range of 5 nm to 50 nm, and the second ITO film has a thickness of 10 nm to 200 nm.
It was confirmed that a sharp opening can be obtained with a film thickness in the range of nm or less.

In the first etching solution containing oxalic acid as a main component, the microcrystallized portions of the first and second ITO films 41 and 43 cannot be removed, and a residue may be produced.
(See Figure 12).

In this case, the ITO films 41 and 43 are formed in the first
After treating with the etching solution of 1), the residue may be etched with dilute hydrochloric acid, dilute sulfuric acid or the like. By these treatments, the residue can be removed without impairing the edge shape.

Next, as a comparative example, in place of the first etching solution, a third etching solution containing ferric chloride, hydrochloric acid, and water (chlorinated third solution) was used for etching the first and second ITO films 41 and 43. Diiron: hydrochloric acid: water = 1: 2: 1) was used, and the second thin film etching solution was used for etching the metal thin film 42, and the transparent conductive film 40 was patterned by the same procedure as above. The composition of the third etching solution is known as the etching solution for the polycrystalline ITO film.

The shape of the patterned transparent conductive film is S
When observed by EM, the side etch was awful
(See Figure 13). Therefore, it was found that the third etching solution is not suitable for forming the pattern of the ITO films 41 and 43.

Next, the difference in etching property between the first and second ITO films 41 and 43 in contact with the metal thin film 42 and the ITO film not in contact with the metal thin film will be described.

First, using the sputtering film forming apparatus 10,
As shown in FIG. 7, a film thickness of 40 n is formed on the surface of the glass substrate 26.
After forming the ITO film 48 of m, it was placed in an oven and heated in an air atmosphere at 200 ° C. for 1 hour (annealing treatment).

Then, as shown in FIG. 8, a patterned resist film 49 was formed on the surface of the ITO film 48.

The ITO film 48 is not in contact with the metal thin film, and the ITO film 48 is exposed on the bottom surface of the opening 50 of the resist film 49. However, even if it is dipped in the first etching solution, The ITO film 48 was not etched by the first etching solution and could not be patterned.

On the other hand, the above-mentioned laminated transparent conductive film 4
At 0, the first and second ITO films 41 and 43 could be etched with the first etching liquid.

The difference in the etching property with respect to the first etching solution is that the ITO film 48 that is not in contact with the metal thin film has large crystal grains during the annealing at 200 ° C. On the contrary, since the first and second ITO films 41 and 43 are in contact with the metal thin film 42 containing silver as a main component during annealing,
It is considered that the crystallization was suppressed, the small crystal grain size was maintained, and the etching property was not deteriorated.

Next, the annealing conditions of the laminated transparent conductive film 40 are made different, and the etching properties of the first and second ITO films 41 and 43 with respect to the first etching liquid and the first IT.
The crystallinity of the O film 43 was observed. The results are shown in Table 1 below.

[0060]

[Table 1]

The crystalline state is the result of measuring the surface of the second ITO film 43 by X-ray diffraction. In Table 1, “None (immediately after film formation)” indicates that annealing is not performed.

X-ray diffraction results are shown in FIGS. 10A to 10C for the second ITO film which was not annealed and the second ITO film which was annealed at 200 ° C. and 300 ° C., respectively. . It is apparent from FIGS. 10A and 10B that the amorphous structure is maintained. Figure 10 (c)
The downward arrow indicates the peak of the ITO crystal.
It can be seen that the crystallization of ITO has progressed at the annealing temperature of 0 ° C.

From the above results, the ITO film that can be patterned with the first etching solution is limited to the ITO film which is in contact with the metal thin film during annealing and which is annealed at a temperature of less than 300 ° C. Presumed to be.

It is presumed that the effect is high when the metal thin film is also a silver alloy thin film containing silver as a main component.

[0065]

EFFECTS OF THE INVENTION The anode electrode film of an organic EL device can be well patterned.

[Brief description of drawings]

FIG. 1 is a diagram for explaining a transparent conductive film of the present invention.

FIG. 2 is a view for explaining the patterning process of the transparent conductive film (1)

FIG. 3 is a view for explaining the patterning process of the transparent conductive film (2)

FIG. 4 is a view for explaining the patterning process of the transparent conductive film (3)

FIG. 5 is a view for explaining the patterning process of the transparent conductive film (4)

FIG. 6 is a view for explaining the patterning process of the transparent conductive film (5)

FIG. 7 is a diagram (1) for explaining a comparative example.

FIG. 8 is a diagram (2) for explaining a comparative example.

FIG. 9 is a view for explaining the manufacturing process of the transparent conductive film of the present invention.

10 (a): X-ray diffraction diagram immediately after forming the transparent conductive film of the present invention, (b): X-ray diffraction diagram after annealing at 200 ° C., (c): After annealing at 300 ° C. X-ray diffraction diagram of

FIG. 11 is an electron micrograph showing an edge shape of a laminated transparent conductive film obtained by etching an ITO film with a first etching solution and a metal thin film with a second etching solution.

FIG. 12 is an electron micrograph showing the residue.

FIG. 13 is an electron micrograph showing an edge shape of a laminated transparent conductive film in which an ITO film is etched with a third etching solution and a metal thin film is etched with a second etching solution.

[Explanation of symbols]

40: laminated transparent conductive film 41: first ITO film 42 ... Metal thin film 43 ... second ITO film

─────────────────────────────────────────────────── ─── Continued Front Page (51) Int.Cl. ⁷ Identification Code FI Theme Coat (Reference) H05B 33/10 H05B 33/10 33/14 33/14 A 33/28 33/28 (72) Inventor Ito Masahiro 523 Yokota, Yamatake-cho, Yamatake-gun, Chiba Inventor Yuji Ichinohe (72) Inventor, Yuji Ichinohe 523 Yokota, Yamatake-cho, Sanmu-gun, Chiba Prefecture In-house, Institute for Supermaterials, Chiba (72) Inventor Lee Jie-hee 523 Yokota, Yamatake-cho, Yamatake-gun, Chiba Prefecture Inventor, Takaba Komatsu, Institute of Supermaterials (72) Takashi Komatsu 523 Yokota Yokota, Yamatake-cho, Yamatake-gun, Chiba Prefecture (72) Inventor, Kensuke Okasaka Saitama Chibabu City 2804 Terao, Aruba Film Co., Ltd. (72) Inventor Kenji Fujii 2804 Terao, Chichibu City, Saitama Prefecture Aruba Film Co., Ltd. In-house (72) Inventor Takahide Sasaki 2804 Terao, Chichibu City, Saitama Prefecture F-term (reference) within Arvac Film Co., Ltd. (reference) 3K007 AB17 AB18 CB04 DB03 FA01 4K029 AA09 BA02 BA04 BA50 BC08 BC09 BD02 CA06 EA08 GA00 4K044 AA12 AB10 BA08 BA10 BA12 BB10 BB15 BC14 CA13 CA62 4K057 WA11 WB01 WB20 WC01 WE02 WE04 WE14 WM03 WN02

Claims (7)

[Claims] 1. A first ITO film formed on a substrate, a transparent metal thin film formed on the surface of the first ITO film, and a second ITO film formed on the surface of the metal thin film. In the laminated transparent conductive film, the first and second ITO films and the metal thin film have a temperature of 300 ° C.
A transparent conductive film formed at a temperature of less than 1. 2. The transparent conductive film according to claim 1, wherein the first and second ITO films and the metal thin film are formed at room temperature. 3. The transparent conductive film is annealed at a temperature of less than 300 ° C.
The transparent conductive film according to claim 1. 4. The transparent conductive film according to claim 1, wherein the metal thin film contains silver as a main component. 5. A first ITO film formed on a substrate, a transparent metal thin film formed on the surface of the first ITO film, and a second ITO film formed on the surface of the metal thin film. And the first and second ITO films and the metal thin film have a temperature of 300 ° C.
A patterning method for patterning a laminated transparent conductive film formed at a temperature of less than, wherein a patterned resist film is formed on the second ITO film, and at least the second ITO film is formed using oxalic acid. First to contain
Patterning method of etching with the etching solution of. 6. The metal thin film is composed of a silver alloy thin film containing silver as a main component, and the metal thin film is etched with a second etching liquid containing a mixture of phosphoric acid and nitric acid. The patterning method described. 7. The patterning method according to claim 5, wherein the first ITO film is etched with the first etching solution, and the patterning method is performed after the etching of the first ITO film. A patterning method of removing an ITO residue with hydrochloric acid or sulfuric acid.