TWI595817B - A wiring formation method, and an etchant for forming a wiring - Google Patents

Description

Wiring forming method, wiring forming etching liquid

The present invention relates to a wiring forming method for forming a wiring including a copper layer and a metal oxide layer, and an etching liquid for wiring formation.

A touch panel type display device or the like used in an electronic device has a display area and a frame edge area around the display area. In the frame edge region, a plurality of wires are formed which are connected to the circuit for detecting the touch position and are drawn from the display region.

As a method of forming the wiring of the rim region, for example, there is a method of forming a wiring by coating a surface of an electrode layer containing a metal oxide or the like on the surface of the electrode layer including the metal oxide as disclosed in JP 2008-77332A. However, in recent years, it has been demanded to reduce the resistance value of the wiring material in order to correspond to a display device which is small and requires high performance as a smart phone or a tablet terminal. Therefore, copper which is lower than the above-mentioned silver paste resistance is being studied as a wiring material.

As a method of forming a wiring when copper is used as a wiring material, a metal wiring constituting the electrode layer exposed between copper wirings is removed by etching after forming a copper wiring on the electrode layer. The electrode layer is a layer containing a metal oxide such as indium tin oxide (ITO) or indium zinc oxide (IZO), and can be etched using hydrochloric acid or the like.

However, when copper is used as the wiring material as described above, when the metal oxide is etched with hydrochloric acid, the copper is corroded, and it is difficult to selectively etch the metal oxide.

In the small display device as described above, it is particularly required to change the frame area Narrow, the wiring width of the frame edge area is also required to be narrow. In the wiring having a narrow width, it is more difficult to selectively etch the metal oxide exposed on the narrow portion without etching the copper layer.

The present invention has been made in view of the problems of the prior art as described above, and provides a wiring forming method and a wiring forming etching liquid which can selectively etch a metal oxide layer.

In the wiring forming method of the present invention, An etching step is performed in which the etching liquid is brought into contact with a portion of the metal oxide layer on which the conductor pattern of the copper-containing layer is formed, and the portion of the conductor pattern is not laminated, and the metal oxide layer of the portion is etched. By the etching step, wiring including the patterned metal oxide layer and the copper layer is formed.

The metal oxide layer contains an oxide of one or more metals selected from the group consisting of zinc, tin, aluminum, indium, and gallium. The etching solution is an acidic aqueous solution containing a thiocarbonyl compound and a halide ion.

According to the invention, since the specific etching liquid is used, corrosion of the conductor pattern of the copper-containing layer can be suppressed, and the metal oxide layer in which the portion of the conductor pattern is not laminated can be selectively etched.

Further, the "copper layer" in the present invention may be a layer composed of copper or a layer containing a copper alloy containing copper and other metals.

As one aspect of the present invention, the metal oxide (hereinafter also referred to as a metal oxide) may be crystalline. In the case where the metal oxide is crystalline, copper is more easily etched than the metal oxide when the previous etching liquid is used, and thus it is particularly difficult to selectively etch the metal oxide layer. According to the invention, even if the metal oxide is crystalline, the metal oxide layer can be selectively etched.

In another aspect of the invention, the concentration of the thiocarbonyl compound in the etching solution may be 0.05% by mass or more and 50% by mass or less. When the concentration of the thiocarbonyl compound is in the above range, the selective etching property of the above metal oxide tends to be improved.

In another aspect of the invention, the concentration of the halide ion in the etching solution may be 1% by mass or more and 35% by mass or less. When the concentration of the halide ion is in the above range, the etching property of the metal oxide tends to be improved. In particular, when the metal oxide is crystalline, the concentration of the halide ion is preferably 20% by mass or more.

In still another aspect of the present invention, the conductor pattern may further include a cover metal layer disposed on a surface of the copper layer opposite to the side of the metal oxide layer, and the cover metal layer may be selected from the group consisting of aluminum, titanium, and chromium. And one or more metals selected from the group consisting of cobalt, nickel, zinc, molybdenum, silver, and alloys of the metals and copper.

In the case where the conductor pattern includes a metal layer, in the prior art, the so-called "Jaffane corrosion" which causes the corrosion to occur between the metal layer and the copper layer causes corrosion of the conductor pattern, and is difficult to selectively etch. Metal oxide layer. In contrast, the etching method according to the present invention, that is, The conductor pattern includes a cover metal layer, and the metal oxide layer can also be selectively etched.

Furthermore, the metal covering the metal layer in the present invention means one or more metals selected from the group consisting of aluminum, titanium, chromium, cobalt, nickel, zinc, molybdenum, silver, and alloys of the metals and copper. The material is different from the above copper layer.

The wiring forming etching liquid of the present invention is used for etching the metal oxide layer in a portion where the conductor pattern is not laminated, in the wiring forming method of the present invention, and is an acidic aqueous solution containing a thiocarbonyl compound and a halide ion.

According to the present invention, it is possible to provide a wiring forming method and a wiring forming etching liquid which can selectively etch a metal oxide layer.

Hereinafter, a method of forming a wiring of the present invention will be described.

The wiring forming method of the present embodiment is an etching step of etching a portion of the metal oxide layer in which the etching solution is formed with a metal oxide layer having a conductor pattern containing a copper layer on the surface thereof, and etching the metal oxide layer in the portion. A wiring including the patterned metal oxide layer and the copper layer described above is formed. The etching solution is an acidic aqueous solution containing a thiocarbonyl compound and a halide ion.

(metal oxide layer)

In the present embodiment, the metal oxide layer removed in the etching step is a layer containing an oxide of one or more metals selected from the group consisting of zinc, tin, aluminum, indium, and gallium.

The metal oxide may be a single metal oxide or a composite metal oxide. For example, ZnO, SnO ₂ , Al ₂ O ₃ , indium tin oxide (ITO), indium zinc oxide (IZO), or a composite metal oxide doped with a dissimilar metal in ZnO may, for example, be mentioned. Examples of the composite metal oxide doped with a dissimilar metal in the ZnO include AZO doped with aluminum, GZO doped with gallium, and the like.

In view of the pattern formation property, a metal oxide layer containing an oxide of one or more metals selected from the group consisting of zinc, tin, and aluminum is preferable, and more preferably contains a metal oxide layer selected from the group consisting of ITO and IZO. A metal oxide layer of one or more metal oxides of AZO and GZO.

The metal oxide may be a metal oxide of either amorphous or crystalline, and in the case of crystallinity, adhesion to a substrate or the like forming a metal oxide layer is improved, and conductivity and durability are also improved. Therefore, it is better.

Further, whether or not the metal oxide is crystalline can be discriminated by, for example, observing the surface of the metal oxide layer by a field emission type transmission electron microscope (FE-TEM). In the case where the metal oxide is crystalline, for example, a polygonal or oblong crystal grain can be observed. In the present embodiment, the crystalline metal oxide refers to a case where the surface area of the metal oxide is observed by the field emission type transmission electron microscope (FE-TEM), and the area ratio of the crystal grains exceeds 50%. The metal oxide is preferably a metal oxide having an area ratio of the crystal grains of 70% to 100%.

The metal oxide layer may be directly provided on a resin substrate such as a polyethylene terephthalate film (PET film) or a glass substrate, or may be provided on the substrate via an undercoat layer containing SiO ₂ or the like. on. As a method of providing the metal oxide layer on the substrate, for example, a known method such as vacuum deposition or sputtering can be employed. The preferred thickness of the metal oxide layer is about 5 to 200 nm.

(conductor pattern)

The conductor pattern in the present embodiment includes a copper layer provided on the metal oxide layer and a cover metal layer provided on the copper layer as needed.

[copper layer]

The copper layer can be formed on the upper surface of the metal oxide layer by a known method such as vacuum deposition or sputtering. The copper layer preferably has a thickness of about 20 to 1000 nm. The copper layer may be a layer containing pure copper or may be a layer containing a copper alloy containing copper and other metals.

[covering metal layer]

In the upper surface of the copper layer of the present embodiment, the cover metal layer may be provided for rust prevention or the like of the copper layer. Examples of the material of the coating metal layer include aluminum, titanium, chromium, cobalt, nickel, zinc, molybdenum, silver, and alloys of the metals and copper. In the case where the copper layer contains a copper alloy, the cover metal layer preferably contains a copper alloy different from the material of the copper layer or a metal other than copper. In view of the rust preventive property of the copper layer and the pattern formability, it is preferably one or more selected from the group consisting of nickel, molybdenum, and alloys of the metals and copper. It is especially preferred to be a nickel-copper alloy having a nickel/copper mass ratio of 30/70 to 70/30.

The cover metal layer may be a single layer or a plurality of layers. The thickness of the above covering metal layer is preferably about 5 to 200 nm. As a method of forming the covering metal layer, for example, a known method such as vacuum vapor deposition or sputtering can be mentioned.

The conductor pattern containing the above copper layer and the cover metal layer as needed generally forms a pattern having a line/gap of 1 μm/1 μm to 100 μm/100 μm.

<<Conductor pattern forming step》

In the wiring forming method of the present embodiment, the conductor pattern forming step of forming the conductor pattern may be performed before the etching step. As a method of forming the conductor pattern, for example, a method in which a resist such as a dry film is provided on the upper surface of the copper layer or the surface of the cover metal layer before pattern formation, and etching is performed, and an etching composition capable of etching the metal is used. The portion covered by the resist is contacted and etched.

The etching composition is not particularly limited as long as it is a composition capable of etching the copper layer, and examples thereof include an acidic aqueous solution containing copper chloride, an acidic aqueous solution containing ferric chloride, or a previously known etching for forming a copper pattern. Composition and the like.

Hereinafter, a case where the conductor pattern provided with the above-mentioned covering metal layer is formed will be described. To form a conductor pattern, the overlying metal layer is etched using an etching composition that etches the metal covering the metal layer, and then the copper layer is etched with an etchable copper etching composition, thereby forming a conductor pattern. Alternatively, etching may be performed using a composition that can simultaneously etch both the copper layer and the cover metal layer.

In the case where the covering metal layer is provided with a coating metal layer containing a nickel-copper alloy, it is particularly preferable to use one or more selected from the group consisting of inorganic acid and organic acid containing an oxidizing metal ion source. An etchant of an acid and an aqueous solution of an azole having only a nitrogen atom as a hetero atom of a hetero ring is used as an etching composition. When using the etchant, it can be etched simultaneously The copper layer and the metal layer are covered, and thus are preferred.

Specific examples of the components of the etchant are preferably the following components.

Examples of the oxidizing metal ion source include a copper (II) ion source such as a copper (II) salt and an iron (III) ion source such as an iron (III) salt. Specific examples of the copper (II) ion source include copper chloride, copper sulfate, copper bromide, an organic acid copper salt, and copper hydroxide. Further, specific examples of the iron (III) ion source include iron chloride, iron bromide, iron iodide, iron sulfate, iron nitrate, and an organic acid iron salt. Among the above oxidizing metal ion sources, a copper (II) ion source is preferably used from the viewpoint of stability of etching rate. Especially in the case of using copper chloride (copper (II) chloride), the etching speed becomes faster, which is preferable.

Examples of the inorganic acid include sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid, and the like. Examples of the organic acid include formic acid, acetic acid, oxalic acid, maleic acid, benzoic acid, and glycolic acid. Among the above acids, hydrochloric acid is preferably used from the viewpoint of stability of etching rate and solubility stability of copper.

The azole having only a nitrogen atom as a hetero atom of the hetero ring may be a monocyclic compound or a compound obtained by condensing a ring. In particular, an imidazole compound, a triazole compound, and a tetrazole compound are preferable, and a tetrazole compound is more preferable from the viewpoint of suppressing the reduction of the conductor pattern. Two or more kinds of these azoles may be used in combination.

Examples of the imidazole-based compound include imidazoles such as imidazole, 2-methylimidazole, 2-undecyl-4-methylimidazole, and 2-phenylimidazole, benzimidazole, and 2-methylbenzimidazole. 2-undecylbenzimidazole, 2-phenylbenzene Benzimidazoles such as imidazole and 2-mercaptobenzimidazole.

Among them, benzimidazole is preferably used.

Examples of the triazole-based compound include 1,2,3-triazole, 1,2,4-triazole, 5-phenyl-1,2,4-triazole, and 5-amino-1,2. , 4-triazole, benzotriazole, 1-methylbenzotriazole, tolutriazole, and the like.

Among them, benzotriazole is preferably used.

Examples of the tetrazole-based compound include 1H-tetrazole, 5-amino-1H-tetrazole, 5-methyl-1H-tetrazole, 5-phenyl-1H-tetrazole, and 5-mercapto-1H. - tetrazole, 1-phenyl-5-mercapto-1H-tetrazole, 1-cyclohexyl-5-mercapto-1H-tetrazole, 5,5'-bis-1H-tetrazole, and the like.

Among them, 1H-tetrazole and 5-amino-1H-tetrazole are preferably used.

The concentration of the oxidizing metal ion source is preferably 0.1% by mass or more and 5% by mass or less based on the metal ion concentration. The concentration of the above acid is preferably 0.5% by mass or more and 15% by mass or less. The concentration of the above azole is preferably 0.1% by mass or more and 1% by mass or less.

For example, when the etchant containing a copper (II) ion source, hydrochloric acid, or a tetrazole-based compound is used as the etchant, the copper (II) ion concentration is preferably 0.5% by mass or more and 3% by mass or less. The concentration of hydrochloric acid is 1% by mass or more and 10% by mass or less based on the concentration of hydrogen chloride, and the concentration of the tetrazole compound is 0.2% by mass or more and 0.4% by mass or less. When the respective components are in the above-described concentration range, even when the copper layer and the metal layer are simultaneously etched, the conductor pattern can be suppressed from being thinned or the like.

The method of using the etchant is not particularly limited, and for example, the etchant is sprayed on a portion of the cover metal layer that is not covered with a resist. A method of immersing a substrate on which the above-mentioned metal layer and the copper layer is formed, in the etchant, or the like.

Among them, a method of etching by spraying is preferred.

In the case where the conductor pattern is formed by spraying using the above etchant, it is preferred to maintain the temperature of the etchant at 20 to 50 ° C and a spray pressure of 0.03 to 0.3 MPa. Further, other conditions such as the flow rate of the spray and the impact force of the spray covering the surface of the metal layer may be appropriately set.

Etching Step

In this embodiment, the etching step is performed to form a wiring including the patterned metal oxide layer and the copper layer: the etching liquid is brought into contact with the portion of the metal oxide layer on which the conductor pattern is formed, and the conductor pattern is not laminated. The metal oxide layer of the exposed portion is etched.

(etching solution)

As the etching liquid for etching the above metal oxide, an acidic aqueous solution containing a thiocarbonyl compound and a halide ion is used.

[thiocarbonyl compound]

The thiocarbonyl compound has a chain thiocarbonyl compound in which a carbon of a thiocarbonyl group (>C=S) is bonded by a chain structure, and a cyclic thiocarbonyl compound which is bonded by a cyclic structure. Specifically, examples of the chain thiocarbonyl compound include a thiourea compound, a thiuram compound, a dithiocarbamic acid compound, a xanthogen compound, ethyl methylthione, and 2,4-pentane. Mercaptan, thioacetamide, and the like.

Further, examples of the cyclic thiocarbonyl compound include 2-thiouracil and 2-sulfur Barbituric acid, 2-thioxanthine, 2-thiocoumarin, thiobarbital, cyclohexylthione, 2-thioxo-4-thiazolidinone (Rhodanine) and the like.

The thiocarbonyl compound used in the etching solution of the present embodiment may be either a chain or a ring, but a chain thiocarbonyl compound is preferred from the viewpoint of solubility. Further, specific examples thereof include the following compounds.

As the thiourea compound, 1-ethylindenyl-2-thiourea, 1-allyl-3-(2-hydroxyethyl)-2-thiourea, 1-mercapto-2-thiourea, 1 , 3-diethylthiourea, 1,3-diphenylthiourea, 1,3-dibutylthiourea, 1,3-dimethylthiourea, thiourea, tributylthiourea, trimethyl Thiourea, 1,3-bis(dimethylaminopropyl)-2-thiourea, tetramethylthiourea, N-methylthiourea, and the like.

Examples of the thiuram compound include tetramethylthiuram disulfide, tetraethylthiuram disulfide, and tetrabutylthiuram disulfide.

Examples of the dithiocarbamic acid compound include 2-(N,N'-diethylthiocarbamoylthio)benzothiazole, zinc dimethyldithiocarbamate, and diethyldisulfide. Nickel carbazide, nickel dibutyl dithiocarbamate, sodium dibutyl dithiocarbamate, and the like.

Examples of the xanthogen compound include zinc butyl xanthate and isopropyl xanthogen.

From the viewpoint of selectively etching the metal oxide layer, it is preferred to use a thiourea compound as the above thiocarbonyl compound. Further, among the above thiourea compounds, an alkylthiourea compound having an alkyl group as a substituent is preferable, and more preferably, the total carbon number of alkyl groups such as tetramethylthiourea or 1,3-diethylthiourea is More than 4 alkylthiourea compounds. When an alkylthiourea compound having an alkyl group having a total carbon number of 4 or more is used in the above etching liquid, formation of a guide can be suppressed The resist such as a dry film provided in the body pattern is peeled off during etching.

The concentration of the thiocarbonyl compound in the etching solution is preferably in the range of 0.05% by mass to 50% by mass, more preferably 0.05% by mass to 30% by mass, even more preferably 0.1% by mass to 20% by mass. The following range. When the concentration is 0.05% by mass or more, the metal oxide layer can be selectively etched. In addition, when the concentration is 50% by mass or less, precipitation of the thiocarbonyl compound in the etching solution can be prevented.

It is considered that the etching liquid of the present embodiment can suppress the corrosion of copper due to the following mechanism.

Usually, if copper is eluted into the etching solution in the form of Cu ²⁺ by etching the copper-containing material with an acidic solution, the Cu ²⁺ acts as a strong copper oxidizing agent, thereby corroding copper.

The thiocarbonyl group of the thiocarbonyl compound forms a complex with copper. Therefore, as described above, at the time of using an etching solution, in particular in a continuous etching the copper layer from the amount of elution than a certain case of Cu ^2+, thiocarbonyl coordinated by Cu ²⁺ and Cu ²⁺ of inhibiting oxidation.

It is considered that by the above mechanism, corrosion of the copper layer can be suppressed while selectively etching the metal oxide.

[halide ion]

Examples of the halide ion used in the etching solution of the present embodiment include a fluoride ion, a chloride ion, a bromide ion, and an iodide ion. From the viewpoint of the etching property and handleability of the metal oxide, it is preferred. It is a chloride ion or a bromide ion, more preferably a chloride ion. The halide ion can be chlorinated by, for example, an acid such as hydrochloric acid or hydrobromic acid or sodium chloride, ammonium chloride or chlorination. A salt such as calcium, potassium chloride, potassium bromide, sodium fluoride or potassium iodide is formulated as a halide ion source and contained in an etching solution.

The concentration of the halide ion in the etching solution is preferably in the range of 1% by mass to 35% by mass, more preferably 5% by mass to 32% by mass, even more preferably 10% by mass to 30% by mass. The following range. When the concentration is 1% by mass or more, the etching property of the metal oxide layer is improved. In addition, when the concentration is 35% by mass or less, precipitation of a halide in the etching liquid can be prevented.

When the metal oxide is crystalline, the etching tends to be difficult to proceed compared with the case of the amorphous material. Therefore, the concentration of the halide ion in the etching solution is preferably 10% by mass or more, and further preferably. It is 15% by mass or more, and particularly preferably 20% by mass or more. Generally, such a solution having a higher concentration of halide ions also functions as an etchant for copper, and thus it is difficult in the prior art to selectively etch only the metal oxide layer. On the other hand, in the present invention, since the etching liquid contains a thiocarbonyl compound as described above, corrosion of the copper layer is suppressed. Therefore, even when the concentration of the halide ions in the etching liquid is increased in order to etch the crystalline metal oxide, the corrosion of the copper layer can be suppressed to selectively etch the metal oxide layer.

[acid]

The etching liquid of this embodiment is an acidic aqueous solution.

The acid to be added for acid formation is not particularly limited, and examples thereof include a sulfonic acid compound such as methanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, or taurine, hydrochloric acid, sulfuric acid, nitric acid, and fluoroboric acid. A mineral acid such as phosphoric acid, or a carboxylic acid such as formic acid, acetic acid, propionic acid or butyric acid.

The preferred concentration of the acid in H ⁺ concentration of 0.001 mass% to 1 mass%, and further preferably 0.3 mass% or less of the range of 0.9% by mass, and particularly preferably 0.4 mass% to 0.8 mass% of the range.

Among them, in the case of using hydrochloric acid, it is preferred to adjust the etching liquid to be acidic while also becoming the source of the halide ion. In the case of using hydrochloric acid, the concentration of the hydrogen chloride in the etching solution is preferably 1% by mass or more and 36% by mass or less, more preferably 10% by mass or more and 33% by mass or less, and particularly preferably 15% by mass or more. The range of mass % or less. In the case where the metal oxide is crystalline, it is particularly preferred that the concentration of hydrogen chloride in the etching solution is 20% by mass or more.

An additive such as a surfactant or a stabilizer may be added to the etching solution of the present embodiment as needed.

Further, in the etching liquid used in the present embodiment, the temperature used has an influence on the etching performance of the metal oxide. Therefore, it is preferred to adjust the respective components, particularly the halide ion concentration, depending on the temperature of the etching liquid to be used. Set to the appropriate concentration range.

For example, when hydrochloric acid is used as the source of the halide ion, when the temperature of the etching liquid is 25 to 45 ° C, if the concentration of hydrochloric acid is adjusted to be in the range of 17.5% by mass or more and 28% by mass or less based on the concentration of hydrogen chloride, The etching performance of the metal oxide is further improved, and thus it is preferable.

Particularly, from the viewpoint of the etching performance of the metal oxide, the concentration of hydrochloric acid is preferably about 28% by mass in terms of hydrogen chloride concentration when the temperature of the etching liquid is 25 ° C, and is 24.5% by mass or more in terms of hydrogen chloride concentration at 30 ° C. When the temperature is 35 to 40 ° C, the concentration of hydrogen chloride is 21% by mass or more, and when it is 45 ° C, The hydrogen chloride concentration is 17.5% by mass or more.

The method of etching the metal oxide layer by using the etching solution in the present embodiment is not particularly limited, and for example, the etching liquid is sprayed on a metal oxide layer exposed between the conductor patterns formed by the resist. The above method, or a method of immersing the substrate on which the conductor pattern is formed in the etching liquid, or the like.

From the viewpoint of the etching performance of the metal oxide, the treatment temperature at the time of etching with the above etching liquid is preferably 25 to 50 °C. For example, when the etching step is carried out by spraying, it is preferred to spray the etching liquid at a spray pressure of 0.03 to 0.3 MPa. Other conditions such as the flow rate of the spray at this time and the impact force of the spray on the surface of the metal oxide may be appropriately set.

The metal oxide exposed between the conductor patterns can be etched by performing an etching step using the above etching liquid. The conductor pattern includes the copper layer and the cover metal layer as needed. However, since the etching liquid selectively etches the metal oxide, corrosion of the copper layer of the conductor pattern can be suppressed, and the metal oxide can be etched.

In the case where a covering metal layer containing a dissimilar metal (a material different from the copper layer) is formed on the copper layer, if the etching is performed with the previous etching liquid, the copper layer is corroded by the japany corrosion. Hey. However, in the case of using the etching liquid of the present embodiment, even if the dissimilar metal, that is, the covering metal layer and the copper layer are mixed, the progress of corrosion of the copper layer can be suppressed.

The method for forming the wiring of the present embodiment is not particularly limited as long as it is applied to a method of forming a wiring containing a metal oxide layer and a copper layer. In the wiring formation of various devices such as a liquid crystal element, an organic EL element, a touch panel, an electronic paper, and a photoelectric conversion element, it is particularly suitable for wiring formation in a frame edge region of a display device.

In addition, the embodiments disclosed herein are to be considered as illustrative and not restrictive. The scope of the present invention is defined by the scope of the claims, and is intended to include all modifications within the meaning and scope of the claims.

[Examples]

Next, an embodiment of the present invention will be described together with a comparative example. Furthermore, the invention is not limited to the following examples.

"Selective Etching of ITO" (production of sample substrate)

Prepare the following substrate: on a PET film with a thickness of 100 μm, a layer of crystalline ITO (thickness 20 nm), a copper layer (thickness 150 nm), and a nickel/copper mass ratio = 70/30 nickel are sequentially formed. - Copper alloy layer (thickness 20 nm). The formation of the conductor pattern was carried out using the substrate in the following procedure.

The substrate was immersed in a 10% by mass aqueous sulfuric acid solution at 25 ° C for 1 minute to remove the oxide on the surface of the nickel-copper alloy layer.

A dry film (model SPG-152, manufactured by ASAHI KASEI E-materials Co., Ltd.) was used on the surface of the nickel-copper alloy layer of the above substrate to form a dry film resist pattern having a line/gap = 31 μm / 31 μm.

The substrate was treated at a liquid temperature of 25 ° C and a spray pressure of 0.1 MPa for 20 seconds using an etchant containing an aqueous solution containing 5.3% by mass of hydrogen chloride, 4.0% by mass of copper chloride, and 0.3% by mass of 5-amino-1H-tetrazole. Etching the nickel-copper alloy layer and For the copper layer, a sample substrate having a cross-sectional view as shown in Fig. 1(a) was produced.

That is, the sample substrate is formed with a metal oxide layer 2 containing ITO on the upper surface of the PET film 1, and a wire (L) / gap (S) = 31 μm / 31 μm is formed on the surface of the metal oxide layer 2 The conductor pattern 6 is provided with the copper layer 3 and the nickel-copper alloy layer, that is, the cover metal layer 4. A dry film resist pattern 5 is formed on the cover metal layer 4.

The sample substrate described above was treated under the following conditions using the etching liquid shown in Table 1. Further, each etching liquid was adjusted to have a copper (II) ion concentration of 2 ppm using a 1% by mass aqueous copper chloride solution.

Further, a sample substrate was produced in the same manner as above except that the nickel-copper alloy layer was not provided, and the following treatment was carried out as Comparative Example 2.

(Evaluation of the retention of the width of the copper layer)

Each sample substrate was immersed in each etching liquid shown in Table 1 at 40 ° C for 1 minute, and then washed with water and dried. At this time, a part of each of the sample substrates was sampled and observed by a scanning electron microscope (Model JSM-7000F, manufactured by JEOL Ltd.), and as a result, the exposed portions 7 between the conductor patterns 6 were obtained (refer to FIG. 1(a). The ITO layer has been removed. As an example, a surface SEM photograph of the conductor pattern 6 when etching with the etching solution of Example 2 is shown in Fig. 2 . As shown in Fig. 2, since no crystal grains of ITO (polygonal crystal grains) were observed, it was found that ITO was completely removed.

Then, the substrate was immersed in a 1% by mass aqueous sodium hydroxide solution at 30 ° C for 2 minutes to dissolve and remove the dry film.

Then, one part of each substrate is sampled at 10 mm×10 mm, embedded in the filling resin, and ground to obtain a guide as shown in FIG. 1(b). The cross section of the bulk pattern 6 was measured by an image using a scanning electron microscope (Model JSM-7000F, manufactured by JEOL Ltd.) to measure the width of the thinnest portion (w) of the copper layer 3.

The results are shown in Table 1.

(Evaluation of adhesion of resist pattern)

Each sample substrate was immersed in each etching liquid shown in Table 1 at 40 ° C for 1 minute, and then washed with water and dried. The resist pattern after drying was visually observed, and the resist pattern adhesion of the sample base material in which the resist pattern was completely peeled off from the upper surface of the conductor pattern was evaluated as C.

The sample substrate on which the resist pattern was not peeled off was adhered to a resist pattern by a finger press glass tape (trade name: Sellotape No. 405, manufactured by NICHIBAN Co., Ltd.), and then peeled off. The resist pattern adhesion of the sample substrate from which the agent pattern was peeled off was evaluated as B, and the sample substrate which was not peeled off was evaluated as A.

The results are shown in Table 1.

"AZO's Choice Etchability"

A substrate was prepared in which a layer of AZO containing crystals (thickness: 20 nm), a copper layer (thickness: 150 nm), and a molybdenum layer (thickness: 20 nm) were sequentially formed on a glass substrate having a thickness of 2 mm. The formation of the conductor pattern was carried out using the substrate as follows.

The substrate was immersed in a 10% by mass aqueous sulfuric acid solution at 25 ° C for 1 minute to remove the oxide on the surface of the molybdenum layer.

A liquid resist (Model OFPR-800, manufactured by Tokyo Ohka Kogyo Co., Ltd.) was used on the surface of the molybdenum layer of the above substrate to form a line/gap = 31 A resist pattern of μm/31 μm.

The substrate was treated at a liquid temperature of 25 ° C and a spray pressure of 0.1 MPa for 20 seconds using an etchant containing an aqueous solution containing 10.0% by mass of hydrogen chloride, 4.0% by mass of copper chloride, and 0.3% by mass of 5-amino-1H-tetrazole. Etching the molybdenum layer and the copper layer.

The sample substrate was treated in the same manner as in the above-described ITO selective etching property evaluation, and the immersion time to the etching liquid described in Table 1 was 30 seconds, and the evaluation was performed in the same manner. Further, each etching liquid was adjusted to a copper (II) ion concentration of 2 ppm using a 1 mass% copper chloride aqueous solution. Further, a sample substrate was produced in the same manner as the above-mentioned AZO selective etching property evaluation except that the molybdenum layer was not provided, and the same evaluation was carried out as Comparative Example 2. The results are shown in Table 1. Further, a part of each sample substrate was sampled and subjected to surface observation using a scanning electron microscope (Model JSM-7000F, manufactured by JEOL Ltd.), and as a result, the AZO layer exposed between the conductor patterns was removed.

"GZO's choice of etching"

Prepare the following substrate: on a glass substrate with a thickness of 2 mm, a layer of crystal-containing GZO (thickness 20 nm), a copper layer (thickness 150 nm), and a nickel/copper mass ratio = 30/70 nickel are sequentially formed. - Copper alloy layer (thickness 20 nm). The formation of the conductor pattern was carried out using the substrate as follows.

The substrate was immersed in a 10% by mass aqueous sulfuric acid solution at 25 ° C for 1 minute to remove the oxide on the surface of the nickel-copper alloy layer.

On the surface of the nickel-copper alloy layer of the above substrate, a dry film (Model SPG-152, manufactured by ASAHI KASEI E-materials Co., Ltd.) was used to form a line/ Dry film resist pattern with gap = 31 μm / 31 μm.

The substrate was treated at a liquid temperature of 25 ° C and a spray pressure of 0.1 MPa for 20 seconds using an etchant containing an aqueous solution containing 5.3% by mass of hydrogen chloride, 4.0% by mass of copper chloride, and 0.3% by mass of 5-amino-1H-tetrazole. Etching the nickel-copper alloy layer and the copper layer.

Using this sample substrate, the immersion time to the etching liquid shown in Table 1 was set to 30 seconds in the selective etching property evaluation of the above ITO, and the same procedure was carried out, and the same evaluation was performed. Further, each etching liquid was adjusted to a copper (II) ion concentration of 2 ppm using a 1% by mass aqueous copper chloride solution. Further, a sample base material was produced in the same manner as the above-mentioned GZO selective etching property evaluation except that the nickel-copper alloy layer was not provided, and the same evaluation was carried out as Comparative Example 2. The results are shown in Table 1. Further, a part of each sample substrate was sampled and subjected to surface observation using a scanning electron microscope (Model JSM-7000F, manufactured by JEOL Ltd.), and as a result, the GZO layer exposed between the conductor patterns was removed.

In each of the examples, the width of the copper layer was also maintained after the treatment with the etching solution of Table 1 as compared with each of the comparative examples. Further, in each of the examples, a resist pattern remained after the etching liquid of Table 1. In Examples 2 to 4 and 7 in which the alkylthiourea compound having a total carbon number of 4 or more was used as the thiocarbonyl compound, the adhesion of the resist pattern was good.

1‧‧‧PET film

2‧‧‧ metal oxide layer

3‧‧‧ copper layer

4‧‧‧ covering metal layer

5‧‧‧ dry film resist pattern

6‧‧‧Conductor pattern

7‧‧‧Exposed part

Fig. 1(a) is a schematic cross-sectional view showing a sample substrate used in the examples, and Fig. 1(b) is a schematic cross-sectional view showing a sample substrate subjected to an etching treatment in the examples.

Fig. 2 is a view showing an SEM photograph of the surface of the example.

1‧‧‧PET film

2‧‧‧ metal oxide layer

3‧‧‧ copper layer

4‧‧‧ covering metal layer

5‧‧‧ dry film resist pattern

6‧‧‧Conductor pattern

7‧‧‧Exposed part

Claims (6)

A wiring forming method for forming a wiring layer including a patterned metal oxide layer and a copper layer by performing an etching step of forming a metal oxide layer having a conductor pattern of the copper layer on a surface thereof A portion of the conductor pattern is not laminated, and the metal oxide layer of the portion is etched, and the metal oxide layer contains an oxide of one or more metals selected from the group consisting of zinc, tin, aluminum, indium, and gallium. The etching solution is an acidic aqueous solution containing a thiocarbonyl compound and a halide ion. The wiring forming method of claim 1, wherein the oxide of the above metal is crystalline. The wiring forming method according to claim 1 or 2, wherein a concentration of the thiocarbonyl compound in the etching solution is 0.05% by mass or more and 50% by mass or less. The wiring forming method according to claim 1 or 2, wherein the concentration of the halide ion in the etching solution is 1% by mass or more and 35% by mass or less. The wiring forming method according to claim 1 or 2, wherein the concentration of the halide ion in the etching solution is 20% by mass or more. The wiring forming method of claim 1 or 2, wherein the conductor pattern further comprises a covering metal layer provided on a surface of the copper layer opposite to the side of the metal oxide layer, and the covering metal layer is selected from the group consisting of aluminum and titanium. And one or more metals selected from the group consisting of chromium, cobalt, nickel, zinc, molybdenum, silver, and alloys of the metals and copper.