JP6817655B2 - Etching solution and its use - Google Patents

Description

The present invention relates to an etching technique for a transparent conductive film containing an indium oxide used in a liquid crystal display or the like, and more particularly to an etching solution used for etching a transparent conductive film having a pattern made of a copper conductor on its surface and its use.

Transparent conductive films such as ITO (indium-tin oxide) films are widely used in the field of electronic devices such as antistatic films, heat reflective films, photoelectric conversion elements, and transparent electrodes of various flat panel displays. Recently, with the spread of portable information terminals, notebook PCs, small TVs, etc., the demand for liquid crystal displays (LCDs) is increasing.

Sensors using an ITO film are widely used in touch panels, and in recent years, in addition to improving their sensitivity and responsiveness, improvements such as the screen itself becoming larger have been rapidly progressing. As a method for forming a fine electrode pattern on a transparent conductive film typified by such an ITO film, a wet method, that is, a transparent electrode film portion not masked with an etching solution composed of an acidic aqueous solution containing halogen ions is used. A method of removing is used (Patent Document 1).

In recent years, copper, which is relatively inexpensive and has good conductive performance, has been adopted as a metal used in a circuit for supplying power to the circuit of the ITO film, and has become mainstream. However, since the conventional etching solution has an oxidizing action on the metal layer and also has a corrosive action on copper, it cannot be applied as it is to etching a transparent conductive film having a pattern made of a copper conductor. ..

The etching solution (Patent Document 2) already completed by the applicant is composed of a halogenic acid, a halogen metal salt, an oxidizing agent and a residual diluent, and is the amount of corrosion of the copper conductor in the etching solution for the ITO film currently used. It is a drug with little etching. However, even if etching is performed using this etching solution, the dissolution of the copper conductor cannot be ignored, and damage to the high-definition copper circuit pattern is unavoidable.

Further, in the method of collectively etching the copper conductor and the ITO film using an etching solution containing ferric chloride, hydrochloric acid, and an oxidizing agent (Patent Documents 3 and 4), the manufacturing process of the transparent electrode pattern is efficient. Although there is an advantage that it can be formed, there is a problem that the etching of the copper conductor in the upper layer of the ITO film proceeds too much and the resistance value of the feeding circuit increases.

Further, a method has been proposed in which different etching solutions are used properly for etching the copper film and etching of the transparent conductor layer (Patent Document 5), but the composition of each etching solution has not been examined in detail here. It cannot be said that it has reached a practical level.

Further, conventionally, it has been pointed out that the etching rate of the etching solution for the ITO film changes with time as one of the problems (Patent Documents 6 and 7).

Japanese Unexamined Patent Publication No. 2015-60937 Japanese Patent No. 4897148 Japanese Unexamined Patent Publication No. 2011-114194 Japanese Unexamined Patent Publication No. 2013-89731 Japanese Unexamined Patent Publication No. 2014-52737 Japanese Unexamined Patent Publication No. 2017-10996 JP-A-2002-241968

The present invention has been made in view of the above points, and the object thereof is to selectively select an ITO circuit while maintaining a high etching rate for a crystalline transparent conductive film and without corroding a conductor containing copper as a main component. It is to realize the technology of etching. Another object of the present invention is to provide an etching method for a transparent conductive film capable of etching only an ITO conductor while suppressing dissolution of a copper conductor. Another object of the present invention is to obtain an etching solution having little change with time.

As a result of efforts to solve the above-mentioned problems, the present inventors were able to selectively dissolve the transparent conductive film without corroding the conductor containing copper as a main component, and the change with time was suppressed. , We have completed a new and high-performance etching solution. That is, the present invention is as follows.

(1)
It contains (a) hydrogen halide, (b) metal halide, (c) copper dissolution inhibitor, (d) diluent, and may optionally contain (e) oxidizing agent.
The above (a) hydrogen halide consists of one or more selected from hydrogen chloride, hydrogen bromide, and hydrogen iodide.
The metal halide (b) is composed of one or more selected from the halides of the first, second and thirteenth elements in the periodic table of elements.
The copper dissolution inhibitor (c) is composed of one or more selected from hydroxylamine and a salt thereof.
The diluent (d) is composed of water and / or an organic solvent, and may optionally contain phosphoric acids.
The above-mentioned (e) oxidizing agent comprises one or more selected from chlorates, nitrates or nitrites of alkali metals and / or alkaline earth metals, perchloric acid, nitric acid, hydrogen peroxide, and organic peroxides.
Used for etching transparent conductive films having a conductor pattern containing copper as the main component on the surface.
Etching solution.

(2)
A transparent conductive film having a conductor pattern containing copper as a main component on the surface contains (a) hydrogen halide, (b) metal halide, (c) copper dissolution inhibitor, and (d) diluent, and optionally ( e) A method for etching a transparent conductive film having a conductor pattern containing copper as a main component on the surface, which comprises a step of contacting with an etching solution containing an oxidizing agent.
The above (a) hydrogen halide consists of one or more selected from hydrogen chloride, hydrogen bromide, and hydrogen iodide.
The metal halide (b) is composed of one or more selected from the halides of the first, second and thirteenth elements in the periodic table of elements.
The copper dissolution inhibitor (c) is composed of one or more selected from hydroxylamine and a salt thereof.
The diluent (d) is composed of water and / or an organic solvent, and may optionally contain phosphoric acids.
The above-mentioned (e) oxidizing agent comprises one or more selected from chlorates, nitrates or nitrites of alkali metals and / or alkaline earth metals, perchloric acid, nitric acid, hydrogen peroxide, and organic peroxides.
A method for etching a transparent conductive film having a conductor pattern containing copper as a main component on the surface.

(3)
The following steps 1 to 4;
(Step 1) A step of forming a transparent conductive film on a substrate,
(Step 2) A step of forming a conductor film containing copper as a main component on the transparent conductive film.
(Step 3) A step of etching a conductor film containing copper as a main component to form a conductor pattern containing copper as a main component on a transparent conductive film.
(Step 4) A transparent conductive film having a conductor pattern containing copper as a main component obtained in step 3 on the surface is provided with (a) hydrogen halide, (b) metal halide, (c) copper dissolution inhibitor, and (. d) A step of etching a transparent conductive film by contacting it with an etching solution containing a diluent and optionally (e) an oxidizing agent to form a transparent electrode pattern.
It is a method of forming a transparent electrode pattern having a conductor pattern containing copper as a main component on the surface.
In step 4 above
The above (a) hydrogen halide consists of one or more selected from hydrogen chloride, hydrogen bromide, and hydrogen iodide.
The metal halide (b) is composed of one or more selected from the halides of the first, second and thirteenth elements in the periodic table of elements.
The copper dissolution inhibitor (c) is composed of one or more selected from hydroxylamine and a salt thereof.
The diluent (d) is composed of water and / or an organic solvent, and may optionally contain phosphoric acids.
The above-mentioned (e) oxidizing agent comprises one or more selected from chlorates, nitrates or nitrites of alkali metals and / or alkaline earth metals, perchloric acid, nitric acid, hydrogen peroxide, and organic peroxides.
A method for forming a transparent electrode pattern having a conductor pattern containing copper as a main component on the surface.

In the present invention, (c) a copper dissolution inhibitor is newly added to an etching solution in which a main component composed of the above components (a) and (b) and an optional component (d) are dissolved in a diluent (d). As a result, we succeeded in significantly reducing the corrosive action of the etching solution on metallic copper.

By using the etching solution of the present invention, the transparent conductive film can be etched in detail corresponding to the resist pattern without corroding the copper conductor pattern adjacent thereto. By using such an etching method, the copper conductor and the transparent electrode can be patterned with higher definition.

A transparent conductive film having a conductor pattern containing copper as a main component on the surface immediately before etching is schematically represented. A transparent electrode having a conductor pattern containing copper as a main component, which is formed by using the etching solution of the present invention, is schematically represented. Here, the resist pattern has already been removed. (C) A transparent electrode having a conductor pattern containing copper as a main component on the surface, which is formed by using a comparative etching solution containing no copper dissolution inhibitor, is schematically represented. Here, the resist pattern has already been removed.

(Etching liquid)
The etching solution of the present invention contains (a) hydrogen halide, (b) metal halide, (c) copper dissolution inhibitor, (d) diluent, and may optionally contain (e) oxidizing agent.

The above (a) hydrogen halide comprises one or more selected from hydrogen chloride, hydrogen bromide, and hydrogen iodide. Of these, hydrogen chloride (hydrochloric acid) is preferable. Such (a) hydrogen halide is used in the form of (d) dissolved in a diluent, preferably in the form of an aqueous solution. The concentration of (a) hydrogen halide in the etching solution of the present invention is appropriately adjusted according to a desired etching rate, but is generally 0.1 mol% to 7 mol%, preferably 1.0 mol%. It is in the range of ~ 5.0 mol%.

The metal halide (b) comprises one or more selected from the halides of the first, second and thirteenth elements in the periodic table of elements. Such (b) metal halide is generally one or more selected from sodium, potassium, magnesium, calcium, aluminum chloride, bromide, and iodide, and has an element period in that the etching rate can be increased. Chloride of the Group 2 element (alkali earth metal) in the table is preferable, and calcium chloride is particularly preferable. Calcium chloride and other metal halides can also be used in combination. As the calcium chloride, an easily available hydrate can be used. Such (b) metal halides are used in the form of (d) dissolved in a diluent, preferably in the form of an aqueous solution. The concentration of the metal halide in the etching solution of the present invention is appropriately adjusted according to the desired etching rate, but is generally 0.01 mol% to 6 mol%, preferably 0.1 mol%. It is in the range of ~ 5.0 mol%.

The copper dissolution inhibitor (c) comprises one or more selected from hydroxylamine and a salt thereof. As the salt of hydroxylamine, hydroxylammonium chloride, hydroxylammonium nitrate and hydroxylammonium sulfate can be used, and among them, hydroxylammonium chloride is preferable. Such a (c) copper dissolution inhibitor is used in the form of being dissolved in (d) a diluent, preferably in the form of an aqueous solution. The concentration of the (c) copper dissolution inhibitor in the etching solution of the present invention is not limited as long as it is at least a concentration capable of suppressing the copper solubility of the etching solution of the present invention.

(C) When hydroxylammonium chloride is used as the copper dissolution inhibitor, generally, a 20% by weight aqueous solution of hydroxylammonium chloride is prepared on a weight basis to obtain (a) hydrogen halide and (b) halogenation. 1 ml or more of the above aqueous solution is added per 1 L of the mother liquor of the etching solution which may contain a metal, (d) diluent and optionally (e) oxidizing agent, preferably 1 ml to 20 ml in consideration of cost.

The diluent (d) is composed of water and / or an organic solvent, and may optionally contain phosphoric acids. This (d) diluent functions as a solvent for (a) hydrogen halide, (b) metal halide, and (c) copper dissolution inhibitor contained in the etching solution of the present invention, and also serves as a solvent for the etching solution of the present invention. It also functions as a solvent for the (e) oxidizing agent, which is an optional component.

(D) As the water used as the diluent, ion-exchanged water or distilled water is usually used. (D) The organic solvent used as the diluent is not limited as long as it can dissolve the constituent components of the etching solution of the present invention, exhibits relatively low electrical conductivity, and does not affect the etching process. Can be used. Examples of such an organic solvent include methanol, ethanol, isopropanol, 1-propanol, 1-butanol, 2-butanol, t-butanol, 2-methyl-1-propanol, 1-pentanol, 1-hexanol, 1 -Alcohols such as heptanol, 4-heptanol, 1-octanol, 1-nonyl alcohol, 1-decanol, 1-dodecanol; diols such as ethylene glycol, 1,2-propanediol, propylene glycol, butanediol, glycerin or Triols; ketones such as acetone, acetylacetone, methylethylketone; nitriles such as acetonitrile, propionitrile, butyronitrile, isobutyronitrile, benzonitrile; aldehydes such as acetaldehyde and propionaldehyde; ethylene glycol monomethyl ether, propylene glycol mono Lower alkylene glycol monoalkyl ethers such as ethyl ether; ethers such as tetrahydrofuran and dioxane, fluorine-containing alcohols such as trifluoroethanol, pentafluoropropanol, 2,2,3,3-tetrafluoropropanol, and organic solvents such as sulfolane. Can be used. Among such organic solvents, lower alcohols such as methanol, ethanol, isopropanol, and 1-propanol are preferable in terms of ease of handling. Further, a mixture of two or more kinds can be used as such an organic solvent. The diluent (d) of the present invention may be the above-mentioned water, the above-mentioned organic solvent, or a mixture of the above-mentioned water and the organic solvent in an arbitrary amount ratio. ..

(D) Phosphoric acids can also be further dissolved in the diluent. The phosphoric acids used here include all of phosphoric acid, phosphorous acid, and hypophosphorous acid. (D) The ionization equilibrium of the aqueous solution constituting the etching solution of the present invention can be adjusted by adding one or more of these phosphoric acids to the diluent. These phosphoric acids are supplemented at an appropriate concentration according to the characteristics of the material to be etched, such as the transparent electrode film to which the etching solution of the present invention is applied, the substrate in contact with the transparent electrode film, and the metal species such as copper in the conductor. Can be blended in.

As such a diluent (d) of the present invention, water and / or alcohol is typically used.

The above-mentioned (e) oxidizing agent increases the etching rate of the etching solution of the present invention and reduces the corrosion of the device material by (a) hydrogen halide and (b) metal halide contained in the etching solution of the present invention. Therefore, it is an ingredient used as needed. Such (e) oxidizing agent is one or more selected from chlorates, nitrates or nitrites of alkali metals and / or alkaline earth metals, perchloric acid, nitric acid, hydrogen peroxide, and organic peroxides. , Preferably sodium or calcium chlorates, nitrates, hydrogen peroxide, organic peroxides. (E) When an oxidizing agent is used, the amount added is not limited as long as it does not exceed the saturation amount, but is preferably 0.01 mol% or more, more preferably 0.01 mol% to the total amount of the etching solution. It is 2.0 mol%.

Further, from the viewpoint of the etching rate, the halogen concentration per 1 L of the etching solution of the present invention is 1 mol to saturated amount, and 10% by weight to 90% by weight of the total halogen amount contained in the etching solution is the above-mentioned (b) halide. It is preferably supplied from metal.

(Etching method)
By contacting the etching solution of the present invention with a transparent conductive film having a conductor pattern containing copper as a main component on the surface, the transparent conductive film having a conductor pattern containing copper as a main component on the surface can be dissolved by melting the copper conductor. It can be etched without causing it.

The "conductor containing copper as a main component" in the present invention is not only when the conductor is composed of a simple substance of copper, but also when the conductor is composed of a simple substance layer of copper and a layer of a composite oxide or alloy containing copper. Including the case.

A transparent conductive film having a conductor pattern mainly composed of copper on its surface is typically a film in which a circuit pattern composed of a conductor mainly composed of copper is formed on an ITO (indium-tin oxide) film. is there. Such a circuit pattern is formed in the electrode area connected to the display area. Therefore, a typical example of the transparent conductive film having a conductor pattern containing copper as a main component in the present invention is a portion having a so-called lead-out electrode.

At the time of contact between the transparent conductive film having a conductor pattern containing copper as a main component on the surface and the etching solution of the present invention, a resist pattern corresponding to the pattern of the transparent electrode is formed on the film. By the etching method of the present invention, a portion of the transparent conductive film not covered with the resist pattern is etched to form a transparent electrode pattern. Since the etching solution of the present invention does not dissolve copper, only the transparent conductive film is etched in this etching method in a state where the copper pattern already formed on the transparent conductive film is well preserved. As a result, a high-definition copper pattern and a transparent electrode pattern are formed.

The method of contacting the etching solution of the present invention with a transparent conductive film having a conductor pattern containing copper as a main component on the surface follows a conventional method of etching treatment. Generally, the etching solution of the present invention heated to 30 ° C. to 70 ° C. is brought into contact with a transparent conductive film having a conductor pattern containing copper as a main component on the surface by a dipping method or a spraying method at this temperature. .. The immersion time in the immersion method, the amount of the spray liquid in the spray method, and the like are appropriately set in consideration of the etching rate. At this time, it is also possible to reduce the corrosion of the equipment material and extend the life of the equipment by etching while blowing a gaseous oxidant such as oxygen, chlorine, nitric oxide, or ozone.

(Method of forming a transparent electrode pattern)
A transparent electrode pattern can be formed by a method including the following steps using the etching method of the present invention.

(Step 1) This is a step of forming a transparent conductive film on a substrate according to a conventional method. As the substrate, a substrate made of glass, quartz, polyethylene terephthalate (PET), polyether sulfone (PES), etc., which is used for LCD (liquid crystal display), touch panel, etc. Used. Examples of the transparent conductive film include a film made of ITO (indium tin oxide), indium oxide, tin oxide, and zinc oxide. As the transparent conductive film of the present invention, an ITO film is preferable, and a crystal type ITO film is particularly preferable. As a method for forming a transparent conductive film on a substrate, any of sputtering, film vapor deposition, vacuum vapor deposition using ion assist, CVD (chemical vapor deposition), coating, spin coating, and spraying can be used. it can. The thickness of the transparent conductive film is selected according to the thickness according to the target device, but is generally in the range of 100 Å to 5000 Å.

(Step 2) This is a step of forming a conductor film containing copper as a main component on the transparent conductive film according to a conventional method. As a method for forming a conductor film containing copper as a main component, there are methods such as sputtering, CVD, and electroplating, but sputtering is generally used.

(Step 3) This is a step of etching the conductor film containing copper as a main component to form a conductor pattern containing copper as a main component on a transparent conductive film. In step 3, a resist material is applied onto a conductor film containing copper as a main component to form a photomask in which a pattern is drawn on the surface of the resist material. Next, the resist material is irradiated with energy rays such as electromagnetic waves and electron beams through a photomask. The resist material is developed to form a resist pattern.

Next, the conductor film containing copper as a main component is etched. The etching solution used in step 3 is an etching solution that does not corrode the transparent conductive film. As such an etching solution, an acidic etching solution such as a persulfuric acid-based etching solution or a hydrogen peroxide-based etching solution can be used. After selectively etching the copper, the film is washed.

(Step 4) This is a step of etching a transparent conductive film having a conductor pattern containing copper as a main component on the surface obtained in step 3 with the etching solution of the present invention. In step 4, a resist material is applied onto a transparent conductive film having a conductor pattern containing copper as a main component obtained in step 3 on the surface, and a photomask having a pattern drawn on the surface of the resist material is formed. Next, the resist material is irradiated with energy rays such as electromagnetic waves and electron beams through this photomask. The resist material is developed to form a resist pattern. The transparent conductive film thus obtained is brought into contact with the etching solution of the present invention as described above, and the conductor pattern already formed on the transparent conductive film is well preserved and is not protected by a resist. The transparent conductive film portion is selectively etched. After selectively etching the ITO film, the film is washed.

[Examples 1 to 6, Comparative Example 1]
As shown below, an ITO film having a conductor pattern made of copper on its surface is etched with the etching solution of the present invention and (c) a comparative etching solution that does not contain a copper dissolution inhibitor, and after etching. The pattern formation of the copper conductor and the ITO electrode was compared.

(Manufacturing of etching solution)
Table 1 shows the formulations of (a) hydrochloric acid as a hydrogen halide, (b) calcium chloride as a metal halide, (d) water as a diluent, and (e) calcium nitrate as an optional oxidizing agent. To prepare a mother liquor of the etching solution. The concentrations (mol%) shown in Table 1 are the concentrations of (a), (b), and (e) diluted with (d) water. The present invention comprises an amount of (c) a 20 wt% aqueous solution of hydroxyammonium hydrochloride as a copper dissolution inhibitor added and mixed per 1 L of this mother liquor, and then allowed to stand for a certain period of time (t) shown in Table 1. Was used as the etching solution (Examples 1 to 6). When t is 0, it indicates that the copper dissolution inhibitor (c) shown in Table 1 was added to the mother liquor and used for etching immediately after mixing.

On the other hand, (c) a mother liquor to which a copper dissolution inhibitor was not added was used as an etching solution for comparison (Comparative Example 1).

Dihydrate is used as the calcium chloride shown in Table 1, and the concentration thereof indicates the calcium chloride concentration in the mother liquor. Dihydrate is used as the calcium nitrate shown in Table 1, and the concentration thereof indicates the calcium nitrate concentration in the mother liquor.

(Etching and formation of transparent electrode pattern)
(Step 1) An ITO film having a thickness of 1500 Å was formed on a PET substrate having a thickness of 0.25 mm by sputtering. (Step 2) A copper film having a thickness of 1 μm was formed on the obtained ITO film by sputtering. (Step 3) A resist material was applied onto a copper film, and the resist material was exposed and developed through a photomask. In this way, a resist pattern was formed on the copper film. The copper film was etched with a commercially available acidic etching solution. In this way, a conductor pattern made of copper was formed on the ITO film. (Step 4) A resist material was applied to an ITO film on which a conductor pattern made of copper was formed, and the resist material was exposed and developed through a photomask. In this way, a conductor pattern made of copper and a resist pattern on the ITO film were formed. The resist pattern was formed with a resist line width of about 40 μm and a resist line interval of about 20 μm.

The ITO film having a conductor pattern made of copper thus obtained was immersed in the etching solution of the present invention prepared as follows and the etching solution for comparison.

Separately, an ITO film having a thickness of 1500 Å was provided separately on a PET substrate having a thickness of 0.25 mm by sputtering, and this film was used as a standard film for determining the immersion time. The standard film was immersed in each of the etching solutions shown in Table 1 in advance, and the time from the start of immersion to the completion of dissolution of the ITO film was defined as the standard time (T). The completion of dissolution of the ITO film was confirmed by the fact that the surface resistance value of the standard film measured by the tester showed infinity. The smaller T is, the higher the etching rate of each etching solution is.

An ITO film having a conductor pattern made of copper was immersed in each of the etching solutions shown in Table 1 over a time corresponding to T × 1.5. At the time of immersion, the temperature of each etching solution was maintained at 30 ° C.

Etching was performed over a sufficient period of time in this way. After the immersion was completed, the ITO film having a conductor pattern made of copper was washed and dried. In this way, the ITO electrode pattern was formed by using the etching method using the etching solution of the present invention and the etching solution for comparison.

(Evaluation)
Through etching (step 4) using the etching solutions of Examples 1 to 6 and Comparative Example 1, it was verified to what extent the shape of the resist pattern formed in step 3 was reproduced as the ITO electrode pattern.

FIG. 1 schematically shows an ITO film having a conductor pattern made of copper on its surface immediately before etching in step 4.

The resist line spacing (S1) immediately before etching was measured at four different points, and the average value (S1av) of the four values (S11, S12, S13, S14) was obtained.

The resist line width (L1) immediately before etching was measured at four different points, and the average value (L1av) of the four values (L11, L12, L13, L14) was obtained.

FIG. 2 schematically shows an ITO electrode pattern having a conductor pattern made of copper on the surface, which is formed by using the etching solution of the present invention (Examples 1 to 6). FIG. 3 schematically shows an ITO pattern having a conductor pattern made of copper on the surface, which is formed by using a comparative etching solution (Comparative Example 1).

The ITO pattern line width (S2) after etching was measured at the four points where S1 was measured, and the average value (S2av) of the four values (S21, S22, S23, S24) was obtained.

The ITO pattern line width (L2) after etching was measured at the four points where L1 was measured, and the average value (L2av) of the four values (L21, L22, L23, L24) was obtained.

The gap (ΔS) between the resist line spacing and the ITO electrode pattern line spacing in the etching using the etching solutions of Examples 1 to 6 and Comparative Example 1 was determined by the formula: ΔS = S1av-S2av. Table 1 shows the values of ΔS corresponding to Examples 1, 2, 3, 4, and Comparative Example 1. The smaller the absolute value of ΔS, the more faithfully the resist pattern line spacing is reproduced in the ITO electrode pattern line spacing by suppressing the corrosion of the copper conductor pattern on the ITO film.

The gap (ΔL) between the resist line width and the ITO electrode pattern line width in the etching using the etching solutions of Examples 1 to 6 and Comparative Example 1 was determined by the formula: ΔL = L1av-L2av. Table 1 shows the values of ΔL corresponding to Examples 1, 2, 3, 4, and Comparative Example 1. The smaller the absolute value of ΔL, the more faithfully the resist pattern line width is reproduced in the ITO electrode pattern line width because the corrosion of the copper conductor pattern on the ITO film is suppressed.

As shown in Table 1, since the ITO film is selectively etched by the etching solution of the present invention containing (c) a copper dissolution inhibitor, the resist pattern is accurately reproduced on the ITO electrode pattern. Such a selective etching effect of the etching solution of the present invention is stable until at least 5 hours have passed since the etching solution was adjusted. Moreover, in the etching using the etching of the present invention, the etching rate does not decrease as compared with the case of Comparative Example 1 in which (c) the copper dissolution inhibitor is not used.

[Example 7, Example 8, Comparative Example 2]
An etching solution was produced under the conditions shown in Table 1. In Examples 8 and 9, etching was performed 24 hours after the addition of (c) a 20 wt% aqueous solution of hydroxyammonium hydrochloride. In Comparative Example 2, the mother liquor 24 hours after the preparation was used for etching.

Etching was performed using the etching solutions of Example 8 and Comparative Example 2 under the same conditions as in Example 1 and evaluated. In the etching using the etching solution of Example 9, the contact method of the etching solution was changed from the immersion method to the spray method, and the other conditions were the same as in Example 1, and the ITO film was etched and evaluated. The results are shown in Table 2.

As shown in Table 2, the selective etching effect of the etching solution of the present invention is maintained even after 24 hours have passed from the preparation of the etching solution or even if the contact method between the etching solution and the ITO film is changed.

[Example 9]
Example 9 is an example in which (c) a 20% by weight aqueous solution of hydroxyammonium hydrochloride was added in portions to the etching solution. In Example 9, 24 hours after adding 2 ml of a 20 wt% aqueous solution of (c) hydroxyammonium hydrochloride to 1 L of the mother liquor shown in Table 1, the same amount of 20 of (c) hydroxyammonium hydrochloride as before was added again. A wt% aqueous solution was added. The ITO film was etched and evaluated under the same conditions as in Example 1 using the etching solution 72 hours after the first addition of hydroxyammonium hydrochloride (c). The results are shown in Table 3.

[Example 10]
Example 10 is also an example in which a 20% by weight aqueous solution of (c) hydroxyammonium hydrochloride was added in portions to the etching solution. In Example 10, 24 hours and 48 hours after adding 2 ml of a 20 wt% aqueous solution of (c) hydroxyammonium hydrochloride to 1 L of the mother liquor shown in Table 1, the same amount of (c) as before was again obtained. A 20 wt% aqueous solution of hydroxyammonium hydrochloride was added. The ITO film was etched and evaluated under the same conditions as in Example 1 using the etching solution 72 hours after the first addition of hydroxyammonium hydrochloride (c). The results are shown in Table 3.

As shown in Table 3, by adding the (c) copper dissolution inhibitor in portions to the etching solution of the present invention, deterioration of the selective etching effect on the ITO film with time can be suppressed.

[Examples 11 and 12]
Examples 11 and 12 are examples in which (e) an oxidizing agent was not added. An etching solution of the present invention was produced by adding 2 ml of a 20 wt% aqueous solution of (c) hydroxyammonium hydrochloride to 1 L of the mother liquor shown in Table 4, and the ITO film was etched and evaluated under the same conditions as in Example 1. The results are shown in Table 4.

As shown in Table 4, in the etching solution of the present invention, (a) hydrogen halide, (b) metal halide, (c) copper dissolution inhibitor, (d) even when (e) no oxidizing agent is contained. ) High etching rate and selectivity for ITO are exhibited by blending a diluent.

The etching solution of the present invention is epoch-making in that it has both an etching rate and selectivity for an ITO film, and has little deterioration with time. By using such an etching solution of the present invention, a transparent electrode pattern having copper wiring can be efficiently produced with high accuracy. The present invention can contribute to the manufacture of liquid crystal displays and touch panels that are required to be thinner and display high-definition images.

1 Substrate 2 ITO film 3 Copper conductor pattern 4 Resist pattern 5 ITO electrode pattern

Claims (3)

It contains (a) hydrogen halide, (b) metal halide, (c) copper dissolution inhibitor, (d) diluent, and may optionally contain (e) oxidizing agent.
The above (a) hydrogen halide consists of one or more selected from hydrogen chloride, hydrogen bromide, and hydrogen iodide.
The metal halide (b) is composed of one or more selected from the halides of the first, second and thirteenth elements in the periodic table of elements.
The copper dissolution inhibitor (c) is composed of one or more selected from hydroxylamine and a salt thereof.
The diluent (d) is composed of water and / or an organic solvent, and may optionally contain phosphoric acids.
The above-mentioned (e) oxidizing agent comprises one or more selected from chlorates, nitrates or nitrites of alkali metals and / or alkaline earth metals, perchloric acid, nitric acid, hydrogen peroxide, and organic peroxides.
Used for etching transparent conductive films having a conductor pattern containing copper as the main component on the surface.
Etching solution. A transparent conductive film having a conductor pattern containing copper as a main component on the surface contains (a) hydrogen halide, (b) metal halide, (c) copper dissolution inhibitor, and (d) diluent, and optionally ( e) A method for etching a transparent conductive film having a conductor pattern containing copper as a main component on the surface, which comprises a step of contacting with an etching solution containing an oxidizing agent.
The above (a) hydrogen halide consists of one or more selected from hydrogen chloride, hydrogen bromide, and hydrogen iodide.
The metal halide (b) is composed of one or more selected from the halides of the first, second and thirteenth elements in the periodic table of elements.
The copper dissolution inhibitor (c) is composed of one or more selected from hydroxylamine and a salt thereof.
The diluent (d) is composed of water and / or an organic solvent, and may optionally contain phosphoric acids.
The above-mentioned (e) oxidizing agent comprises one or more selected from chlorates, nitrates or nitrites of alkali metals and / or alkaline earth metals, perchloric acid, nitric acid, hydrogen peroxide, and organic peroxides.
A method for etching a transparent conductive film having a conductor pattern containing copper as a main component on the surface. The following steps 1 to 4;
(Step 1) A step of forming a transparent conductive film on a substrate,
(Step 2) A step of forming a conductor film containing copper as a main component on the transparent conductive film.
(Step 3) A step of etching a conductor film containing copper as a main component to form a conductor pattern containing copper as a main component on a transparent conductive film.
(Step 4) A transparent conductive film having a conductor pattern containing copper as a main component obtained in step 3 on the surface is provided with (a) hydrogen halide, (b) metal halide, (c) copper dissolution inhibitor, and (. d) A step of etching a transparent conductive film by contacting it with an etching solution containing a diluent and optionally (e) an oxidizing agent to form a transparent electrode pattern.
It is a method of forming a transparent electrode pattern having a conductor pattern containing copper as a main component on the surface.
In step 4 above
The above (a) hydrogen halide consists of one or more selected from hydrogen chloride, hydrogen bromide, and hydrogen iodide.
The metal halide (b) is composed of one or more selected from the halides of the first, second and thirteenth elements in the periodic table of elements.
The copper dissolution inhibitor (c) is composed of one or more selected from hydroxylamine and a salt thereof.
The diluent (d) is composed of water and / or an organic solvent, and may optionally contain phosphoric acids.
The above-mentioned (e) oxidizing agent comprises one or more selected from chlorates, nitrates or nitrites of alkali metals and / or alkaline earth metals, perchloric acid, nitric acid, hydrogen peroxide, and organic peroxides.
A method for forming a transparent electrode pattern having a conductor pattern containing copper as a main component on the surface.

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