KR20120066581A - Etchant and the etching method using the same - Google Patents

Abstract

PURPOSE: Etchant and an etching method using the same are provided to selectively etch a copper layer in an object comprising an oxide layer and the copper layer. CONSTITUTION: Etchant is used for etching an object comprising a copper layer and a metal oxide layer including metal oxide of one or more selected from Zn, Sn, Al, In, and Ga. The etchant is a solution which comprises 0.1-3.0 weight% of copper ion as a second copper ion source, 0.1-30.0 weight% of organic acid with a carbon number of 6 weight% or less, and 0.1-3.0 weight% of one or more nitrogen-containing compounds selected from the group consisting of heterocyclic compounds having two or more nitrogen atoms in a loop and amino-containing compounds. The Ph of the solution is 5.0-10.5.

Description

Etching agent and etching method using the same {ETCHANT AND THE ETCHING METHOD USING THE SAME}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an etchant for etching an object to be treated in which a metal oxide layer and a copper layer coexist, and selectively etching the copper layer.

Conventionally, a conductive metal oxide layer composed of indium tin oxide (ITO), indium zinc oxide (IZO), or the like has been widely used as a transparent conductor by exhibiting high transmittance at low resistance. In addition, the metal oxide semiconductor layer composed of IGZO such as In-Ga-ZnO ₄ and In ₂ -Ga ₂ -ZnO ₇ has been studied by the application of various devices such as electronic paper. When the metal oxide layer is applied to various devices, the metal oxide layer is generally used in the form of coexistence with the patterned metal layer in the shape of an electrode.

The processing method in which the metal oxide layer and the patterned metal layer coexist, includes a workpiece in which a metal oxide layer is laminated on the metal layer, a workpiece in which a metal layer is laminated on the metal oxide layer, or a metal layer next to the metal oxide layer. There is known a method of preparing a workpiece which coexists with a metal oxide layer and a metal layer, such as a workpiece to be set, and selectively etching the metal layer using an etchant.

For example, Patent Document 1 below describes a method for producing a liquid crystal device in which an ITO layer and a patterned aluminum layer coexist, and a mixed acid composed of phosphoric acid, acetic acid, and nitric acid is used as an etchant for the aluminum layer.

[Prior Art Literature]

[Patent Document 1] Publication No. 10-96937

In recent years, the electrode wiring of the display field has tended to use fine wiring in response to requests for large screen size and high miniaturization, so that resistance electrodes lower than aluminum electrodes are required. Therefore, using a copper electrode instead of an aluminum electrode is examined. However, existing copper etchant has not been sufficiently studied for the configuration capable of selectively etching the copper layer in the workpiece (workpiece) in which the metal oxide layer and the copper layer coexist. In particular, since the finer the finer the thickness of the transparent metal oxide layer, such as the ITO layer used in the touch panel, is a fatal defect when the transparent metal oxide layer is eroded by the etchant of the copper layer. Therefore, there is a need for an etchant capable of selectively etching only a copper layer without eroding the metal oxide layer.

SUMMARY OF THE INVENTION The present invention has been devised in view of the above circumstances, and provides an etching agent and an etching method using the same, which are used for etching a workpiece having a metal oxide layer and a copper layer coexist, and which can selectively etch the copper layer.

In order to achieve the above object, the etchant of the present invention is used for the etching of a workpiece having a metal oxide layer and a copper layer coexisting with at least one metal oxide selected from Zn, Sn, Al, In and Ga, Heterocyclic compound having 0.1 to 3.0% by weight of the second copper ion source as copper ions, 0.1 to 30.0% by weight of organic acid having 6 or less carbon atoms, and two or more nitrogen atoms in the ring with an etchant that selectively etches the copper layer. And an aqueous solution containing 0 to 30.0% by weight of at least one nitrogen-containing compound selected from the group consisting of amino group-containing compounds having 8 or less carbon atoms, and the pH is 5.0 to 10.5.

In addition, in the etching method of the present invention, a metal oxide layer containing at least one metal oxide selected from Zn, Sn, Al, In, and Ga and a workpiece to coexist with a copper layer are treated with an etching agent to treat the copper layer. In the etching method of selectively etching, the said etching liquid is the etching agent of the said invention, It is an etching method characterized by the above-mentioned.

In the etching agent and the etching method of the present invention, the "copper layer" may be made of copper or may be made of a copper alloy. In addition, in this specification, "copper" means copper or a copper alloy.

According to the etching agent and the etching method of this invention, when etching the to-be-processed object which a metal oxide layer and a copper layer coexist, only the said copper layer can be selectively etched. In this way, for example, when manufacturing the apparatus which a metal oxide layer and a patterned metal layer coexist, a yield can be improved and manufacturing cost can be reduced.

The etchant of the present invention is used for etching a metal oxide layer including at least one metal oxide selected from Zn, Sn, Al, In and Ga and a workpiece to which a copper layer coexists, and selectively etching the copper layer. The etchant is intended. The metal oxide constituting the metal oxide layer may be either 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), there may be mentioned, such as IGZO, such as _{ZnO 7 - in - Ga - ZnO} 4 and in ₂ - Ga _2. In view of preventing erosion of the metal oxide layer when etching the copper layer, a metal oxide layer containing at least one metal oxide selected from Zn, Sn and Al is preferred, and ZnO, SnO ₂ , Al ₂ O ₃ , ITO More preferred are metal oxide layers containing at least one metal oxide selected from IZO and IGZO.

(Second copper ion source)

In the etchant of the present invention, the second copper ion source is a component that acts as a copper oxidant. As said 2nd copper ion source, the copper complex of the nitrogen containing compound mentioned later, copper hydroxide, the copper complex of the organic acid mentioned later, copper carbonate, copper sulfate, copper oxide, or copper halides, such as copper chloride or copper bromide, are mentioned, for example. Can be mentioned. In the present invention, these may be used alone or in combination. Among them, copper formate, copper acetate, copper chloride, and copper bromide are preferable from the viewpoint of improving the etching rate.

The content of the second copper ion source is 0.1 to 3.0% by weight, preferably 0.25 to 2.5% by weight, and more preferably 0.5 to 2.0% by weight of copper ions from the viewpoint of improving the etching rate.

(Organic acid with 6 or less carbon atoms)

In the etchant of the present invention, the organic acid having 6 or less carbon atoms is blended as a component for dissolving oxidized copper. It is preferable that it is 1-5, and, as for the said organic acid carbon number from a viewpoint of the solubility improvement of copper, it is more preferable that it is 1-4. In addition, the said organic acid may be mix | blended with an etching agent independently, and may be mix | blended with an etching agent as a copper complex.

As said organic acid, an aliphatic carboxylic acid, aromatic carboxylic acid, etc. are mentioned, for example. As a specific example of the said aliphatic carboxylic acid, For example, Aliphatic saturated monocarboxylic acids, such as formic acid, acetic acid, a propionic acid, butyric acid, a gil acetic acid, a caproic acid; Aliphatic unsaturated monocarboxylic acids such as acrylic acid, crotonic acid and isocrotononic acid; Aliphatic saturated dicarboxylic acids such as hydroxyl, maronic acid, succinic acid, glutaric acid, adipic acid and pimeric acid; Aliphatic unsaturated dicarboxylic acids such as maleic acid; Oxycarboxylic acids such as glycolic acid, lactic acid, malic acid, citric acid; Carboxylic acids having substituents such as thrumic acid, β-chloropropionic acid, nicotinic acid, ascorbic acid, hydroxy pivalate acid and levulinic acid; And derivatives thereof. In the present invention, these may be used alone or in combination. Among these, aliphatic saturated monocarboxylic acid, aliphatic saturated dicarboxylic acid, and oxycarboxylic acid are preferable since they do not inhibit the oxidation of copper and there is no danger of causing an increase in viscosity of the etchant. Formic acid, acetic acid, propionic acid, butyric acid, caproic acid, Fisheries, lactic acid, malic acid and citric acid are more preferred.

The organic acid content is 0.1 to 30.0% by weight, preferably 0.5 to 20.0% by weight, more preferably 1.0 to 10.0% by weight. If the organic acid content is 0.1% or more, the solubility of copper oxide is improved. Moreover, when content of the said organic acid is 30.0 weight% or less, the fall of copper dissolution stability can be suppressed and crystal precipitation of an organic acid can be prevented.

(Nitrogen-containing compound)

The at least one nitrogen-containing compound selected from the group consisting of a heterocyclic compound having two or more nitrogen atoms in the ring and an amino group-containing compound having 8 or less carbon atoms in the etchant of the present invention retains dissolved copper as an complex in the etchant. It is mix | blended as a component to make. The present invention can use one kind or several kinds of nitrogen-containing compounds. In addition, the said nitrogen containing compound may be mix | blended with an etching agent independently, and may be mix | blended with an etching agent as a copper complex. In addition, the said nitrogen containing compound does not contain the said organic acid.

The heterocyclic compound is not particularly limited as long as it has two or more nitrogen atoms in the ring, and examples thereof include azoles such as imidazoles, pyrazoles, triazoles, tetrazole and derivatives thereof. . From the viewpoint of complexability with dissolved copper, pyrazoles such as imidazoles such as imidazole and benz imidazole or pyrazoles are preferable. Specifically, imidazole, 2-methyl imidazole, 1,2-diethyl imidazole, benz imidazole, pyrazole, triazole, benztriazole, etc. can be illustrated, Among them, imidazole, 2-methyl Preferred are imidazole, 1,2-diethylimidazole, benz imidazole and pyrazole.

The amino group-containing compound is not particularly limited as long as it has 8 or less carbon atoms, but is preferably 0 to 7 carbon atoms, and more preferably 0 to 5 carbon atoms from the viewpoint of complexability with dissolved copper.

As said amino-group containing compound, For example, Ammonia; Alkyl ammoniums such as methyl ammonium, dimethyl ammonium and trimethyl ammonium; Alkanol amines; Aromatic amines, such as aniline, etc. can be illustrated. Moreover, the amine compound which has 2 or more amino groups, such as ethylene diamine, and quaternary amine compounds, such as tetramethyl ammonium, can also be used. Among them, ammonia and alkanolamine are preferable from the viewpoint of complexability with dissolved copper.

Specific examples of the alkanolamine include monoethanolamine, N-methylethanolamine, N-ethylethanolamine, N-butylethanolamine, N, N-dimethylethanolamine, N, N-diethylethanolamine, Monoethanolamine and derivatives thereof such as 2- (2-hydroxy) ethoxyethanolamine; Diethanolamine and its derivatives such as diethanolamine, N-methyl diethanolamine and N-butyl diethanolamine; Triethanolamine; Propanolamine; Isopropanolamine; Hydroxyethyl piperazine; And derivatives thereof. Among them, monoethanolamine, diethanolamine, and triethanolamine are preferable from the viewpoint of complexability with dissolved copper.

From the viewpoint of complexability with dissolved copper, the nitrogen-containing compound is preferably imidazole, pyrazoles, ammonia, alkanolamine, and imidazole, 2-methylimidazole, 1,2-diethyl It is more preferable that they are midazole, benzimidazole, pyrazole, ammonia, monoethanolamine, diethanolamine, and triethanolamine.

The content of the nitrogen-containing compound is 0.1 to 30.0 wt%, preferably 1.0 to 25.0 wt%, more preferably 10.0 to 20.0 wt%. If content of the said nitrogen containing compound is 0.1% or more, an etching rate can be improved. Moreover, if content of the said nitrogen containing compound is 30.0 weight% or less, the viscosity rise of an etching agent can be suppressed.

(Other additives)

The etching agent of the present invention may contain a halogen ion source in order to improve the solubility and dissolution stability of copper and to increase the etching rate. Specific examples of the halogen ion source include inorganic acids such as hydrochloric acid, hydrobromic acid and hydroiodic acid; Inorganic salts such as copper chloride, copper bromide, iron chloride, sodium chloride, sodium iodide, ammonium chloride and the like. Moreover, in order to perform uniform etching, you may mix | blend surfactants, such as a polyalkylene glycol and a polyalkylene glycol derivative, etc. in order to perform uniform etching. The content of such additives in the etchant is about 0.01 to 10% by weight.

The pH of the etchant of the present invention is 5.0 to 10.5, preferably 5.0 to 10.0, and more preferably 5.0 to 7.0 from the viewpoint of preventing erosion of the metal oxide layer when etching the copper layer. In particular, the pH of the etchant is preferably 5.0 to 7.0 from the viewpoint of preventing erosion of the metal oxide layer including metal oxides of amphoteric metals such as Zn, Sn and Al. In addition, the pH of the etchant can be controlled by adjusting the content of the organic acid and the nitrogen-containing compound.

The etchant of this invention can be prepared easily by melt | dissolving said each component in water. As said water, ion-exchange water is preferable. In addition, the etchant of this invention may be mix | blended so that each said component may be made to predetermined | prescribed density | concentration at the time of use, and the concentrate may be prepared and diluted before use.

The method of using the etchant of the present invention is not particularly limited, and examples thereof include a method of spraying on a workpiece in which a metal oxide layer and a copper layer coexist, a method of immersing the target in an etchant, and the like. In the case of immersion, since the first copper ions generated in the etchant are oxidized to the second copper ions by etching of copper, air blowing by bubbling or the like may be performed. In the etching process, the temperature of the etchant is preferably 10 to 50 ° C, and the processing time is preferably 10 to 120 seconds.

The etchant of this invention is suitable for manufacture of the device etc. which a metal oxide layer and a patterned metal layer coexist. Examples of the electric device include liquid crystal elements, organic EL elements, touch panels, electronic paper, photoelectric conversion elements, and the like.

Next, the Example of the etching agent concerning this invention is demonstrated with a comparative example. In addition, this invention is not interpreted limited to the following Example.

(Etching speed of copper layer)

Copper plate laminated plate (Product Name: Glass Epoxy Multi R-1766) manufactured by Panasonic Electric Co., Ltd., 1.6 mm thick, was immersed in an etchant (200 g / L sulfuric acid, 50 g / L hydrogen peroxide, residual ion-exchanged water) to completely remove the copper foil of the laminate. An electroless plating chemical (trade name: OPC Copper H) manufactured by Okuno Pharmaceutical Industries, Ltd. was used on one side of the glass epoxy substrate, and electroless copper plating having a thickness of about 1.5 μm was applied to the entire surface, and 50 mm × 50 mm was cut to obtain a test substrate. This board | substrate was etched by the spraying process (spray pressure: 0.05 Mpa) for 30 second using each etching agent (temperature: 30 degreeC) in Table 1. And the etching rate was computed by the following formula from the weight of the test board before and behind a process. The results are shown in Table 2. In addition, "not measurable" of Table 2 shows that the weight of a test board does not change even if it is etched for 30 second.

Etch Rate (μm / min) = [Weight Before Treatment (g)-Weight After Treatment (g)] ÷ Board Area (m ² ) ÷ 8.92 (g / cm ³ ) ÷ Treatment Time (minutes)

(Etching speed of ITO layer and IGZO layer)

The thing which formed the ITO film or IGZO film of thickness 0.2 micrometer by sputtering on the float glass base material (made by Asahikara Co., Ltd.) of 100 mm x 100 mm and thickness 2mm was used as a test board | substrate. This test board | substrate was etched by the spray process (spray pressure: 0.1 MPa) using each etching agent (temperature: 30 degreeC) of Table 1, and the surface treated every 30 second of treatment time was measured by XPS. And the etching rate was computed by following Formula from the time when In peak which is one of a composition component disappeared. The results are shown in Table 2. In addition, "not measurable" of Table 2 shows that an In peak does not change even if it etches for 10 minutes.

Etch Rate (μm / min) = 0.2μm ÷ [Process Time (min) until In Peak Loss]

As shown in Table 2, according to the embodiment of the present invention, the difference between the etching rate of the copper layer and the etching rate of the ITO layer or the IGZO layer was larger than that of the comparative example. From this result, according to this invention, it was confirmed that only a copper layer can be selectively etched in the to-be-processed object which a metal oxide layer and a copper layer coexist.

Claims (5)

Second copper in an etchant which selectively etches the copper layer, which is used for etching a workpiece having a metal oxide layer including at least one metal oxide selected from Zn, Sn, Al, In and Ga and a copper layer. In the group consisting of 0.1 to 3.0% by weight of the ion source as copper ions, 0.1 to 30.0% by weight of the organic acid having 6 or less carbon atoms, and a heterocyclic compound having two or more nitrogen atoms in the ring and an amino group-containing compound having 8 or less carbon atoms Etching agent which consists of aqueous solution containing 0.1-30.0 weight% of 1 or more types of nitrogen containing compound chosen, and pH is 5.0-10.5. The etchant according to claim 1, wherein the pH is 5.0 to 7.0. The etchant according to claim 1, wherein the organic acid is at least one selected from the group consisting of aliphatic saturated monocarboxylic acids, aliphatic saturated dicarboxylic acids and oxycarboxylic acids. The etchant according to claim 1, wherein the nitrogen-containing compound is at least one member selected from the group consisting of imidazoles, pyrazoles, ammonia and alkanolamines. In an etching method for selectively etching the copper layer by treating a workpiece with a metal oxide layer and at least one metal oxide selected from Zn, Sn, Al, In and Ga and the copper layer coexist with an etching agent. The etching method is an etching agent according to any one of claims 1 to 4.