Etchant composition

Abstract

To provide an etchant composition with which a metal film is less likely to lose glossiness after being etched.SOLUTION: In one embodiment, the present disclosure relates to an etchant composition for etching a metal film formed on a substrate. The etchant composition contains phosphoric acid, nitric acid, organic acid, a water-soluble organic solvent, an etching inhibitor, and water. The metal film is a metal film including at least one kind of metal selected from among tungsten, tantalum, zirconium, hafnium, molybdenum, niobium, ruthenium, osmium, rhenium, rhodium, copper, nickel, cobalt, titanium, titanium nitride, alumina, aluminum, and iridium.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present disclosure relates to an etching solution composition and an etching method using the same. [Background technology]

[0002] In the manufacturing process of a semiconductor device, a process is carried out in which a film to be etched, which contains at least one metal such as tungsten, tantalum, zirconium, hafnium, molybdenum, niobium, ruthenium, osmium, rhenium, rhodium, copper, nickel, cobalt, titanium, titanium nitride, alumina, aluminum, and iridium, is etched and processed into a predetermined pattern shape. In recent years, the semiconductor industry has become highly integrated, and this has created a demand for more complex and finer wiring. This has resulted in increased demands for pattern processing techniques and etching solutions, and various etching methods have been proposed.

[0003] For example, Patent Document 1 proposes an etching solution for a metal monolayer film or laminated film, which contains an azole, nitric acid, a peroxide, and a water-soluble organic solvent. The document also describes that the etching solution may further contain phosphoric acid, an organic acid, and the like. Patent Document 2 proposes an etching solution for etching a laminated film including a molybdenum film, the etching solution containing an oxidizing agent (e.g., nitric acid), a catalyst (e.g., phosphoric acid, glycols), and a moisture regulator (e.g., organic acid, organic solvent). Patent Document 3 proposes an etching solution for use in manufacturing thin film transistors, the etching solution being composed of phosphoric acid, nitric acid, acetic acid, water, and ethylene glycol or glycerin. Patent Document 4 proposes an etching solution suitable for both tungsten-containing metals and TiN-containing materials, the etching solution comprising water, an oxidizing agent (e.g., phosphoric acid, nitric acid), and one or more components selected from a fluorine-containing etching compound, an organic solvent, a chelating agent, a corrosion inhibitor (e.g., polyethyleneimine), and a surfactant. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2017-195311 A [Patent Document 2] JP 2021-114569 A [Patent Document 3] JP 2002-231706 A [Patent Document 4] JP 2019-165225 A Summary of the Invention [Problem to be solved by the invention]

[0005] In conventional etching methods, when a film containing metals such as tungsten is etched at a high speed, the etching may progress non-uniformly and the glossiness may be lost. In particular, the loss of glossiness may cause problems with laser scattering measuring instruments, making it impossible to accurately measure the surface cleanliness, shape, etc. In the manufacturing process of semiconductor wafers, from the viewpoints of productivity and yield, an etching solution that does not easily lose glossiness is required.

[0006] Therefore, in one aspect, the present disclosure provides an etching solution composition that is less likely to impair the gloss of a metal film after etching. [Means for solving the problem]

[0007] In one aspect, the present disclosure relates to an etching solution composition for etching a metal film formed on a substrate, the etching solution composition comprising phosphoric acid, nitric acid, an organic acid, a water-soluble organic solvent, an etching inhibitor, and water, the metal film being a metal film containing at least one metal selected from tungsten, tantalum, zirconium, hafnium, molybdenum, niobium, ruthenium, osmium, rhenium, rhodium, copper, nickel, cobalt, titanium, titanium nitride, alumina, aluminum, and iridium.

[0008] In one embodiment, the present disclosure relates to an etching method comprising the step of etching a metal film containing at least one metal with an etching solution composition of the present disclosure.

[0009] In one aspect, the present disclosure relates to a substrate processing method, comprising a step of etching a metal film formed on a substrate with an etching solution composition of the present disclosure, the substrate being at least one type of substrate selected from a semiconductor wafer, a substrate for a liquid crystal display device, a substrate for a plasma display, a substrate for an FED (Field Emission Display), a substrate for an optical disk, a substrate for a magnetic disk, a substrate for a magneto-optical disk, a substrate for a photomask, a ceramic substrate, and a substrate for a solar cell. Effect of the Invention

[0010] According to one aspect of the present disclosure, an etching solution composition can be provided that is less likely to impair the gloss of a metal film after etching. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] In one aspect, the present disclosure is based on the discovery that the decrease in gloss of a metal film due to etching can be suppressed by using an etching solution containing phosphoric acid, nitric acid, an organic acid, a water-soluble organic solvent, an etching inhibitor, and water.

[0012] In one aspect, the present disclosure relates to an etching solution composition for etching a metal film formed on a substrate, the etching solution composition comprising phosphoric acid, nitric acid, an organic acid, a water-soluble organic solvent, an etching inhibitor, and water, the metal film being a metal film containing at least one metal selected from tungsten, tantalum, zirconium, hafnium, molybdenum, niobium, ruthenium, osmium, rhenium, rhodium, copper, nickel, cobalt, titanium, titanium nitride, alumina, aluminum, and iridium (hereinafter also referred to as the "etching solution composition of the present disclosure"). According to the etching solution composition of the present disclosure, it is possible to provide an etching solution composition that is less likely to impair the gloss of a metal film after etching.

[0013] Although the details of the mechanism by which the effects of the present disclosure are manifested are not clear, it is presumed as follows. In the present disclosure, it is believed that the etching inhibitor tightly coats the surface of the metal film to be etched or forms a thick protective film, which allows the surface of the metal film to be protected while being slowly etched, thereby suppressing uneven etching and suppressing a decrease in the gloss of the metal film due to etching. In addition, in the present disclosure, it is believed that the combined use of the etching inhibitor and the water-soluble organic solvent enhances the wettability of the etching solution composition to the metal film and promotes the uniform wetting and spreading of the etching inhibitor on the metal film, which is believed to further suppress the progress of non-uniform etching and further suppress the decrease in gloss of the metal film due to etching. From the above, it is believed that the gloss of the metal film is unlikely to be impaired after etching. However, the present disclosure need not be construed as being limited to these mechanisms.

[0014] [phosphoric acid] The amount of phosphoric acid in the etching solution composition of the present disclosure is preferably 10% by mass or more, more preferably 20% by mass or more, and even more preferably 30% by mass or more from the viewpoint of suppressing a decrease in glossiness, and from the same viewpoint, is preferably 80% by mass or less, more preferably 70% by mass or less, and even more preferably 60% by mass or less. More specifically, the amount of phosphoric acid in the etching solution composition of the present disclosure is preferably 10% by mass or more and 80% by mass or less, more preferably 20% by mass or more and 70% by mass or less, and even more preferably 30% by mass or more and 60% by mass or less.

[0015] [nitric acid] The amount of nitric acid in the etching solution composition of the present disclosure is preferably 0.5% by mass or more, more preferably 1% by mass or more, and even more preferably 1.5% by mass or more from the viewpoint of suppressing a decrease in glossiness, and from the same viewpoint, is preferably 20% by mass or less, more preferably 10% by mass or less, and even more preferably 7% by mass or less. More specifically, the amount of nitric acid in the etching solution composition of the present disclosure is preferably 0.5% by mass or more and 20% by mass or less, more preferably 1% by mass or more and 10% by mass or less, and even more preferably 1.5% by mass or more and 7% by mass or less.

[0016] [Organic acid] Examples of organic acids contained in the etching solution composition of the present disclosure include at least one selected from formic acid, acetic acid, propionic acid, butyric acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, maleic acid, fumaric acid, phthalic acid, trimellitic acid, hydroxyacetic acid, lactic acid, salicylic acid, malic acid, tartaric acid, citric acid, aspartic acid, and glutamic acid. From the viewpoint of suppressing the decrease in gloss, the organic acid is preferably a monovalent organic acid having 1 to 10 carbon atoms, more preferably a monovalent carboxylic acid having 1 to 10 carbon atoms, further preferably containing acetic acid, and more preferably acetic acid. The organic acid may be used alone or in combination of two or more kinds.

[0017] The amount of organic acid in the etching solution composition of the present disclosure is preferably 1% by mass or more, more preferably 2% by mass or more, and even more preferably 3% by mass or more from the viewpoint of suppressing the decrease in glossiness, and from the same viewpoint, is preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less. More specifically, the amount of organic acid in the etching solution composition of the present disclosure is preferably 1% by mass or more and 50% by mass or less, more preferably 2% by mass or more and 40% by mass or less, and even more preferably 3% by mass or more and 30% by mass or less. When two or more organic acids are used in combination, the amount of organic acid is the total amount of the organic acids.

[0018] The total amount of phosphoric acid, nitric acid and organic acid in the etching solution composition of the present disclosure is preferably 30% by mass or more, more preferably 40% by mass or more, and even more preferably 45% by mass or more from the viewpoint of suppressing the decrease in glossiness, and from the same viewpoint, is preferably 95% by mass or less, more preferably 90% by mass or less, and even more preferably 85% by mass or less. More specifically, the amount of acid in the etching solution composition of the present disclosure is preferably 30% by mass or more and 95% by mass or less, more preferably 40% by mass or more and 90% by mass or less, and even more preferably 45% by mass or more and 85% by mass or less.

[0019] [Water-soluble organic solvent] In one or more embodiments, the water-soluble organic solvent contained in the etching solution composition of the present disclosure may be at least one of monoalcohols, polyhydric alcohols, glycol ethers, sulfoxides, amides, esters, ketones, and ethers, from the viewpoint of suppressing a decrease in glossiness. Among these, at least one selected from polyhydric alcohols, glycol ethers, and ketones is preferable from the viewpoint of suppressing a decrease in glossiness. The number of carbon atoms of the polyhydric alcohol is preferably 2 to 8, and more preferably 2 to 6, from the viewpoint of suppressing a decrease in glossiness. The valence of the polyhydric alcohol is preferably 2 to 4, and more preferably 2 to 3, from the viewpoint of suppressing a decrease in glossiness. Examples of the polyhydric alcohol include glycols, triols, and glycerin. As the polyhydric alcohol, a polyhydric alcohol having 2 to 8 carbon atoms is preferable, a polyhydric alcohol having 2 to 6 carbon atoms is more preferable, and a glycol having 2 to 6 carbon atoms is even more preferable, from the viewpoint of suppressing a decrease in glossiness. Examples of the glycol having 2 to 6 carbon atoms include ethylene glycol and dipropylene glycol. Examples of the glycol ether include triethylene glycol monomethyl ether. Examples of the ketone include acetone. The water-soluble organic solvent may be one type or a combination of two or more types. In the present disclosure, the water-soluble organic solvent refers to an organic solvent that dissolves in 100 mL of water at 25° C. in an amount of 10 mL or more.

[0020] The amount of the water-soluble organic solvent in the etching solution composition of the present disclosure is preferably 0.1% by mass or more, more preferably 1% by mass or more, and even more preferably 5% by mass or more from the viewpoint of suppressing the decrease in glossiness, and is preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less from the viewpoint of suppressing the decrease in glossiness. More specifically, the amount of the water-soluble organic solvent in the etching solution composition of the present disclosure is preferably 0.1% by mass or more and 50% by mass or less, more preferably 1% by mass or more and 40% by mass or less, and even more preferably 5% by mass or more and 30% by mass or less. When the water-soluble organic solvent is a combination of two or more kinds, the amount of the water-soluble organic solvent is the total amount thereof.

[0021] [Etching inhibitor] The etching inhibitor contained in the etching liquid composition of the present disclosure may be used alone or in combination of two or more kinds.

[0022] From the viewpoint of suppressing a decrease in gloss, the etching inhibitor in the present disclosure preferably has an etching inhibition rate of 20% or more, more preferably 30% or more, even more preferably 40% or more, even more preferably 50% or more, even more preferably 60% or more, even more preferably 70% or more, even more preferably 80% or more, even more preferably 85% or more, even more preferably 90% or more, and even more preferably 94% or more.

[0023] In the present disclosure, the etching inhibition rate refers to the rate of decrease in the etching rate when an etching inhibitor is used relative to the etching rate when no etching inhibitor is used. In one or more embodiments, the etching inhibition rate can be a value obtained by subtracting the relative etching rate A of the etching rate of the etching solution composition from 100 when the etching rate of a mixed acid aqueous solution consisting of phosphoric acid, nitric acid, acetic acid, and water, the mass ratio of the amounts of phosphoric acid, nitric acid, and acetic acid being the same as the mass ratio of the amounts of phosphoric acid, nitric acid, and acetic acid in the etching solution composition, and the total amount of phosphoric acid, nitric acid, and acetic acid being 49 mass%, is taken as 100. The mass ratio of the amounts of each component in the mixed acid aqueous solution can be appropriately set. In one or more embodiments, the etching inhibition rate can be measured by adapting the implementation conditions such as temperature to the conditions for performing etching. Specifically, the etching inhibition rate can be determined by the method described in the Examples. The measurement conditions of the etching inhibition rate vary depending on the metal contained in the etched layer, and the preferred ranges of temperature and time when measuring the etching inhibition rate include the preferred ranges of etching temperature and etching time in the etching step of the present disclosure described later in one or more embodiments. For example, the predetermined temperature and the predetermined time in measuring the etching inhibition rate can be 90°C for 180 minutes when the metal plate used for the measurement is a tungsten plate, 40°C for 10 minutes when the metal plate used for the measurement is a molybdenum plate, and 40°C for 10 minutes when the metal plate used for the measurement is a nickel plate. The shape of the metal plate used for the measurement can be, for example, a plate-like body with a length of 2 cm, a width of 2 cm, and a thickness of 0.1 mm. Specifically, the etching inhibition rate can be determined by the method described in the Examples.

[0024] In one or more embodiments, the etching inhibitor in the present disclosure may be an organic amine compound, such as at least one organic amine compound selected from polyalkyleneimine, a polymer having a constitutional unit derived from diallylamine, polyalkylenepolyamine, and amino acid. Among these, in one or more embodiments, polyalkyleneimine and polyalkylenepolyamine are preferred as the etching inhibitor from the viewpoint of suppressing the decrease in gloss. The polyalkyleneimine includes, for example, polyethyleneimine, and branched polyethyleneimine is preferable. Examples of the polymer containing a constitutional unit derived from diallylamine include a diallylamine / sulfur dioxide copolymer. An example of the polyalkylene polyamine is diethylene triamine. Examples of amino acids include arginine and aspartic acid.

[0025] When the etching inhibitor is a polyalkyleneimine, the number average molecular weight of the etching inhibitor is preferably 300 or more, more preferably 600 or more, and even more preferably 1,200 or more from the viewpoint of suppressing a decrease in gloss, and is preferably 100,000 or less, more preferably 10,000 or less, more preferably 5,000 or less, and even more preferably 3,000 or less from the viewpoint of viscosity. From the same viewpoint, the number average molecular weight of the etching inhibitor is preferably 300 or more and 100,000 or less, more preferably 600 or more and 5,000 or less, and even more preferably 1,200 or more and 3,000 or less. When the etching inhibitor is a polymer containing a structural unit derived from diallylamine, the weight average molecular weight of the etching inhibitor is preferably 2,000 or more, more preferably 3,000 or more, still more preferably 4,000 or more, and from the viewpoint of suppressing the decrease in glossiness, preferably 50,000 or less, more preferably 10,000 or less, still more preferably 7,000 or less. From the same viewpoint, the weight average molecular weight of the etching inhibitor is preferably 2,000 or more and 50,000 or less, more preferably 3,000 or more and 10,000 or less, still more preferably 4,000 or more and 7,000 or less. When the etching inhibitor is a polyalkylene polyamine, the number average molecular weight or molecular weight of the etching inhibitor is preferably 50 or more, more preferably 80 or more, still more preferably 100 or more, and from the viewpoint of suppressing the decrease in glossiness, preferably 1,000 or less, more preferably 500 or less, still more preferably 300 or less. From the same viewpoint, the number average molecular weight or molecular weight of the etching inhibitor is preferably 50 or more and 1,000 or less, more preferably 80 or more and 500 or less, still more preferably 100 or more and 300 or less.

[0026] In the present disclosure, the average molecular weight can be measured by gel permeation chromatography (GPC).

[0027] An example of the method for measuring the average molecular weight of the etching inhibitor of the present disclosure is shown below. <GPC conditions (polyalkyleneimine)> Sample solution: adjusted to a concentration of 0.1 wt% Apparatus / detector: HLC-8320GPC (integrated GPC) manufactured by Tosoh Corporation Column: α-M + α-M (manufactured by Tosoh Corporation) Eluent: 0.15 mol / L Na2SO4, 1% CH3COOH / water Column temperature: 40 °C Flow rate: 1.0 mL / min Sample solution injection volume: 100 μL Standard polymer: pullulan with known molecular weight (Shodex P-5, P-50, P-200, P-800) <GPC conditions (polymer containing structural units derived from diallylamine)> Sample solution: adjusted to a concentration of 0.1 wt% Detector: HLC-8320GPC (integrated GPC) manufactured by Tosoh Corporation Column: α-M + α-M (manufactured by Tosoh Corporation) Eluent: 0.15 mol / L Na2SO4, 1% CH3COOH / water Column temperature: 40 °C Flow rate: 1.0 mL / min Sample solution injection volume: 100 μL Standard polymer: pullulan with known molecular weight (Shodex P-5, P-50, P-200, P-800)

[0028] In one or more embodiments, as the etching inhibitor in the present disclosure, from the viewpoint of suppressing the decrease in glossiness, an organic amine compound having an etching inhibition rate of 20% or more is preferable. Therefore, in one aspect, the present disclosure relates to an etching solution composition for etching a metal film formed on a substrate, the etching solution composition containing phosphoric acid, nitric acid, an organic acid, a water-soluble organic solvent, an etching inhibitor, and water, and the etching inhibitor is an organic amine compound having an etching inhibition rate of 20% or more determined under the following conditions. Here, the etching inhibition rate is a value obtained by subtracting from 100 the relative rate A of the etching rate of the etching solution composition when the etching rate of a mixed acid aqueous solution composed of phosphoric acid, nitric acid, acetic acid, and water, in which the mass ratio of the blending amounts of the phosphoric acid, nitric acid, and acetic acid is the same as the mass ratio of the blending amounts of the phosphoric acid, nitric acid, and acetic acid in the etching solution composition, and the total blending amount of the phosphoric acid, nitric acid, and acetic acid is 49 mass%, is taken as 100.

[0029] The amount of the etching inhibitor in the etching solution composition of the present disclosure is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and even more preferably 0.5% by mass or more from the viewpoint of suppressing the decrease in glossiness, and from the same viewpoint, it is preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 3% by mass or less. More specifically, the amount of the etching inhibitor in the etching solution composition of the present disclosure is preferably 0.01% by mass or more and 10% by mass or less, more preferably 0.1% by mass or more and 5% by mass or less, and even more preferably 0.5% by mass or more and 3% by mass or less. When the etching inhibitor is a combination of two or more kinds, the amount of the etching inhibitor is the total amount thereof. The mass ratio of the amount of the water-soluble organic solvent to the amount of the etching inhibitor in the etching solution composition of the present disclosure (water-soluble organic solvent / etching inhibitor) is preferably 0.02 or more, more preferably 0.1 or more, and even more preferably 1 or more, from the viewpoint of suppressing a decrease in glossiness, and is preferably 5000 or less, more preferably 1000 or less, more preferably 600 or less, and even more preferably 100 or less, from the viewpoint of suppressing a decrease in glossiness. More specifically, the mass ratio (water-soluble organic solvent / etching inhibitor) is preferably 0.02 or more and 5000 or less, more preferably 0.1 or more and 1000 or less, more preferably 1 or more and 600 or less, and even more preferably 1 or more and 100 or less.

[0030] [water] In one or more embodiments, the etching solution composition of the present disclosure contains water. Examples of the water contained in the etching solution of the present disclosure include distilled water, ion-exchanged water, pure water, and ultrapure water.

[0031] The amount of water in the etching solution composition of the present disclosure is preferably 1% by mass or more, more preferably 5% by mass or more, and even more preferably 10% by mass or more, from the viewpoint of suppressing a decrease in glossiness, and is preferably 60% by mass or less, more preferably 50% by mass or less, and even more preferably 45% by mass or less, from the viewpoint of suppressing a decrease in glossiness. More specifically, the amount of water in the etching solution composition of the present disclosure is preferably 1% by mass or more and 60% by mass or less, more preferably 5% by mass or more and 50% by mass or less, and even more preferably 10% by mass or more and 45% by mass or less.

[0032] [Other ingredients] The etching solution composition of the present disclosure may further contain other components within the scope of the present disclosure, such as inorganic acids other than phosphoric acid and nitric acid, chelating agents, surfactants, solubilizing agents, preservatives, rust inhibitors, bactericides, antibacterial agents, and antioxidants.

[0033] In one or more embodiments, the etching solution composition of the present disclosure may be substantially free of azole. The amount of azole in the etching solution composition of the present disclosure is preferably less than 0.005% by mass, more preferably 0.001% by mass or less, and even more preferably 0% by mass (i.e., no azole is contained).

[0034] In one or more embodiments, the etching solution composition of the present disclosure may be substantially free of a fluorine-containing compound. The amount of the fluorine-containing compound in the etching solution composition of the present disclosure is preferably less than 0.01% by mass, more preferably 0.001% by mass or less, and even more preferably 0% by mass (i.e., no fluorine-containing compound is contained).

[0035] From the viewpoint of suppressing the decrease in glossiness, the etching solution composition of the present disclosure preferably does not contain hydrogen peroxide. Here, in one or more embodiments, "does not contain hydrogen peroxide" includes not containing hydrogen peroxide, not containing substantially hydrogen peroxide, or not containing an amount of hydrogen peroxide that affects the etching result. The amount of hydrogen peroxide blended in the etching solution composition of the present disclosure is not particularly limited, but is preferably 3 mass% or less, more preferably 1 mass% or less, even more preferably 0.1 mass% or less, even more preferably 0.01 mass% or less, and even more preferably 0 mass% (i.e., not contained).

[0036] [Method of manufacturing the etching solution composition] In one embodiment, the etching solution composition of the present disclosure is obtained by blending phosphoric acid, nitric acid, an organic acid, a water-soluble organic solvent, an etching inhibitor, water, and the above-mentioned optional components by a known method. Thus, in one embodiment, the present disclosure relates to a method for producing an etching solution composition (hereinafter also referred to as the "etching solution production method of the present disclosure") that includes a step of blending at least phosphoric acid, nitric acid, an organic acid, a water-soluble organic solvent, an etching inhibitor, and water. In the present disclosure, "blending at least phosphoric acid, nitric acid, an organic acid, a water-soluble organic solvent, an etching inhibitor, and water" includes, in one or more embodiments, simultaneously or sequentially mixing phosphoric acid, nitric acid, an organic acid, a water-soluble organic solvent, an etching inhibitor, water, and, if necessary, the optional components described above. The order of mixing is not particularly limited. The blending can be performed using a mixer such as a propeller-type agitator, a pump for liquid circulation agitation, a homomixer, a homogenizer, an ultrasonic disperser, and a wet ball mill. In the method for producing an etching solution according to the present disclosure, the preferred amount of each component may be the same as the preferred amount of each component in the etching solution composition according to the present disclosure described above.

[0037] In the present disclosure, the "amount of each component in the etching solution composition" refers, in one or more embodiments, to the amount of each component in the etching solution composition used in the etching step, i.e., at the time when the use in the etching treatment is started (at the time of use). In one or more embodiments, the blending amount of each component in the etching solution composition of the present disclosure can be regarded as the content of each component in the etching solution composition of the present disclosure. However, when the component is affected by neutralization, the blending amount and the content may differ.

[0038] The embodiment of the etching solution composition of the present disclosure may be a so-called one-liquid type in which all components are supplied to the market in a pre-mixed state, or a so-called two-liquid type in which the components are mixed at the time of use. An example of a two-liquid type etching solution composition is one in which water is separated into a first liquid and a second liquid, phosphoric acid, nitric acid, an organic acid, a water-soluble organic solvent, and an etching inhibitor are contained in either one or both of the first liquid and the second liquid, and the first liquid and the second liquid are mixed at the time of use. Each of the first liquid and the second liquid may contain the above-mentioned optional components as necessary.

[0039] From the viewpoint of suppressing the decrease in glossiness, the pH of the etching solution composition of the present disclosure is preferably 1 or less, more preferably 0 or less, even more preferably less than 0, and even more preferably about -1. The pH of the etching solution composition of the present disclosure can be preferably -5 or more, more preferably -3 or more. In the present disclosure, the pH of the etching solution composition is a value at 25°C, and can be measured using a pH meter, specifically, by the method described in the Examples.

[0040] The etching solution composition of the present disclosure may be stored and supplied in a concentrated state to the extent that its stability is not impaired. In this case, it is preferable in that the manufacturing and transportation costs can be reduced. The concentrated solution can be appropriately diluted with water or an aqueous acid solution as necessary and used in the etching process. The dilution ratio can be, for example, 3 to 100 times.

[0041] [kit] In another aspect, the present disclosure relates to a kit for producing the etching liquid composition of the present disclosure (hereinafter also referred to as the "kit of the present disclosure"). In one or more embodiments, the kit of the present disclosure includes a kit (two-liquid etching solution) that contains a first liquid and a second liquid in a mutually unmixed state, and phosphoric acid, nitric acid, an organic acid, a water-soluble organic solvent, and an etching inhibitor are contained in either one or both of the first liquid and the second liquid, and the first liquid and the second liquid are mixed when used. After the first liquid and the second liquid are mixed, they may be diluted with water or an acid aqueous solution as necessary. The first liquid or the second liquid may contain all or a part of the water used to prepare the etching solution. The first liquid and the second liquid may each contain the above-mentioned optional components as necessary. The kit of the present disclosure may be, for example, a kit (two-liquid etching solution) that contains a solution (Liquid 1a) containing a water-soluble organic solvent and an etching inhibitor, and an aqueous acid solution (Liquid 2a) containing phosphoric acid, nitric acid, and an organic acid in a mutually unmixed state, and that is mixed at the time of use. After Liquid 1a and Liquid 2a are mixed, they may be diluted with water or an aqueous acid solution as necessary. Liquid 1a or Liquid 2a may contain all or a part of the water used to prepare the etching solution. The acid contained in Liquid 2a may be all or a part of the acid used to prepare the etching solution. Liquid 1a may contain an acid. Liquid 1a and Liquid 2a may each contain the above-mentioned optional components as necessary. According to the kit of the present disclosure, an etching solution can be obtained that is less likely to impair the gloss of a metal film after etching.

[0042] [Film to be etched] In one or more embodiments, the film to be etched using the etching solution composition of the present disclosure is a metal film containing at least one metal. Here, the metal is not particularly limited as long as the effects of the present disclosure are achieved, but examples thereof include at least one metal selected from tungsten, tantalum, zirconium, hafnium, molybdenum, niobium, ruthenium, osmium, rhenium, rhodium, copper, nickel, cobalt, titanium, titanium nitride, alumina, aluminum, and iridium. Among these, in one or more embodiments, the etching solution composition of the present disclosure is preferably used for etching a metal film containing at least one metal selected from tungsten, tantalum, zirconium, molybdenum, niobium, and nickel, and in one or more embodiments, is preferably used for etching a tungsten film, a molybdenum film, or a nickel film. That is, in one or more embodiments, the film to be etched is a tungsten film, a molybdenum film, or a nickel film.

[0043] [Etching method] In one aspect, the present disclosure relates to an etching method (hereinafter also referred to as the "etching method of the present disclosure") that includes a step of etching a metal film containing at least one metal using the etching solution composition of the present disclosure (hereinafter also referred to as the "etching step of the present disclosure"). According to the etching method of the present disclosure, it is possible to provide an etching method that does not easily impair the glossiness of the metal film after etching.

[0044] In the etching step of the present disclosure, examples of the etching method include immersion etching and single wafer etching.

[0045] In one or more embodiments, when the film to be etched is a tungsten film, the temperature (etching temperature) of the etching solution composition in the etching step of the present disclosure is preferably 0° C. or higher, more preferably 50° C. or higher, even more preferably 70° C. or higher, and preferably 150° C. or lower, more preferably 130° C. or lower, and even more preferably 110° C. or lower, from the viewpoint of suppressing a decrease in glossiness. From the same viewpoint, in one or more embodiments, when the film to be etched is a tungsten film, the etching temperature is preferably 0° C. or higher and 150° C. or lower, more preferably 50° C. or higher and 130° C. or lower, and even more preferably 70° C. or higher and 110° C. or lower. In one or more embodiments, when the film to be etched is a molybdenum film, the temperature of the etching solution composition in the etching step of the present disclosure (etching temperature) is, from the viewpoint of suppressing a decrease in glossiness, preferably 0° C. or higher, more preferably 15° C. or higher, even more preferably 25° C. or higher, and preferably 80° C. or lower, more preferably 65° C. or lower, and even more preferably 50° C. or lower. From the same viewpoint, in one or more embodiments, when the film to be etched is a molybdenum film, the etching temperature is preferably 0° C. or higher and 80° C. or lower, more preferably 15° C. or higher and 65° C. or lower, and even more preferably 25° C. or higher and 50° C. or lower. In one or more embodiments, when the film to be etched is a nickel film, the temperature of the etching solution composition in the etching step of the present disclosure (etching temperature) is, from the viewpoint of suppressing a decrease in glossiness, preferably 0° C. or higher, more preferably 15° C. or higher, even more preferably 30° C. or higher, and preferably 80° C. or lower, more preferably 65° C. or lower, and even more preferably 50° C. or lower. From the same viewpoint, in one or more embodiments, when the film to be etched is a nickel film, the etching temperature is preferably 0° C. or higher and 80° C. or lower, more preferably 15° C. or higher and 65° C. or lower, and even more preferably 30° C. or higher and 50° C. or lower.

[0046] In the etching process of the present disclosure, the etching time can be set to, for example, 1 minute or more and 180 minutes or less.

[0047] In one or a plurality of embodiments, when the film to be etched is a tungsten film, from the viewpoints of improving productivity and suppressing a decrease in glossiness, the etching rate in the etching step of the present disclosure is preferably 0.0001 mg / min or more, more preferably 0.0005 mg / min or more, and even more preferably 0.001 mg / min or more, and from the viewpoint of suppressing a decrease in glossiness, it is preferably 10 mg / min or less, more preferably 1 mg / min or less, and even more preferably 0.1 mg / min or less. In one or a plurality of embodiments, when the film to be etched is a molybdenum film, the etching rate in the etching step of the present disclosure is, from the viewpoints of improving productivity and suppressing a decrease in glossiness, preferably 0.01 mg / min or more, more preferably 0.03 mg / min or more, and even more preferably 0.05 mg / min or more, and from the viewpoint of suppressing a decrease in glossiness, preferably 10 mg / min or less, more preferably 3 mg / min or less, and even more preferably 1 mg / min or less. In one or more embodiments, when the film to be etched is a nickel film, the etching rate in the etching step of the present disclosure is, from the viewpoints of improving productivity and suppressing a decrease in glossiness, preferably 0.001 mg / min or more, more preferably 0.005 mg / min or more, and even more preferably 0.01 mg / min or more, and from the viewpoint of suppressing a decrease in glossiness, preferably 10 mg / min or less, more preferably 1 mg / min or less, and even more preferably 0.5 mg / min or less.

[0048] In one or a plurality of embodiments, the etching solution composition and the etching method of the present disclosure can be used to etch metals in the manufacturing process of electronic devices, particularly semiconductor wafers. In one or more embodiments, the etching solution composition of the present disclosure and the etching method of the present disclosure can be suitably used for the preparation of at least one substrate selected from a semiconductor wafer, a substrate for a liquid crystal display device, a substrate for a plasma display device, a substrate for an FED (Field Emission Display), a substrate for an optical disk, a substrate for a magnetic disk, a substrate for a magneto-optical disk, a substrate for a photomask, a ceramic substrate, and a substrate for a solar cell. That is, in one aspect, the present disclosure relates to a substrate processing method (hereinafter also referred to as the substrate processing method of the present disclosure) which includes a step of etching a metal film formed on a substrate using the etching solution composition of the present disclosure or the etching method of the present disclosure, and the substrate is at least one substrate selected from a semiconductor wafer, a substrate for a liquid crystal display device, a substrate for a plasma display device, a substrate for an FED (Field Emission Display), a substrate for an optical disk, a substrate for a magnetic disk, a substrate for a magneto-optical disk, a substrate for a photomask, a ceramic substrate, and a substrate for a solar cell. According to the substrate processing method of the present disclosure, the glossiness of the metal film is not easily impaired after etching, so that the productivity and yield can be improved. In one or a plurality of embodiments, the etching solution composition and the etching method of the present disclosure can be used to etch electrodes in the manufacturing process of electronic devices, particularly semiconductor memories such as nonvolatile memories including NAND flash memories. In one or more embodiments, the etching solution composition and the etching method of the present disclosure can be suitably used for producing a pattern having a three-dimensional structure, thereby making it possible to obtain an advanced device such as a large-capacity memory. The etching solution composition and the etching method of the present disclosure can be used, for example, in an etching method such as that disclosed in JP2020-145412A. EXAMPLES

[0049] The present disclosure will be specifically described below with reference to examples, but the present disclosure is not limited to these examples in any way.

[0050] 1. Preparation of Etching Solution (Examples 1 to 13, Comparative Examples 1 to 5) Etching solutions (pH: 0 to -2) of Examples 1 to 13 and Comparative Examples 1 to 5 were prepared by mixing phosphoric acid, nitric acid, an organic acid shown in Table 1, a water-soluble organic solvent shown in Table 1, an etching inhibitor shown in Table 1, and water. The amount of each component (mass %, active content) in the prepared etching solutions is shown in Table 1. The amount of water in Table 1 includes the amount of water contained in the acid aqueous solution, etc.

[0051] The following components were used to prepare the etching solution. Phosphoric acid [Rinkagaku Kogyo Co., Ltd., concentration 85%] Nitric acid [FUJIFILM Wako Pure Chemical Corporation, concentration 70%] (organic acid) Acetic acid [FUJIFILM Wako Pure Chemical Corporation, concentration 100%] (Water-soluble organic solvent) Dipropylene glycol [AGC Inc., 100% concentration] Ethylene glycol [Nippon Shokubai Co., Ltd., 100% concentration] Triethylene glycol monomethyl ether [Tokyo Chemical Industry Co., Ltd., concentration 100%] Acetone [FUJIFILM Wako Pure Chemical Corporation, concentration 100%] (Etching inhibitor) Polyethyleneimine [number average molecular weight 1,800, "Epomin SP-018" manufactured by Nippon Shokubai Co., Ltd.] Diethylenetriamine [molecular weight 103, "DETA" from Tosoh Corporation] (water) Water [Ultrapure water produced using a continuous pure water production system (Pure Conti PC-2000VRL type) and subsystem (Macace KC-05H type) manufactured by Kurita Water Industries Ltd.]

[0052] 2. How to measure the pH of the etching solution The pH value of the etching solution at 25° C. was measured using a pH meter (manufactured by DKK-Toa Corporation), and was the value measured one minute after the electrode of the pH meter was immersed in the etching solution.

[0053] 3.Evaluation of Etching Solutions [Evaluation of tungsten plate etching rate and etching inhibition rate] A tungsten plate with a length of 2 cm, a width of 2 cm, and a thickness of 0.1 mm, the weight of which had been measured in advance, was immersed in the etching solution prepared to each composition (Examples 1 to 13 and Comparative Examples 1 to 5), and the tungsten plate was etched at 90°C for 180 minutes. After that, the tungsten plate was washed with water and then weighed again, and the difference was taken as the amount of etching. A precision balance was used to measure the weight. The etching rate was then calculated using the following formula. Etching rate (mg / min) = amount etched (mg) / etching time (min) The results of the etching rate of the tungsten plate are shown in Table 1. The etching rate of the tungsten plate in Comparative Example 1 was taken as 100, and the relative rate of each Example was subtracted from 100 to obtain the etching inhibition rate (%), which is also shown in Table 1. [Evaluation of the etching rate and etching inhibition rate of nickel plate] The etching rate of the nickel plate was measured in the same manner as the above tungsten etching method, except that a nickel plate measuring 2 cm in length, 2 cm in width, and 0.1 mm in thickness was used instead of the tungsten plate, and the etching conditions were changed to an etching temperature of 40° C. and an etching time of 10 minutes. The results of the etching rate of the nickel plate are shown in Table 1. In addition, the etching inhibition rate (%) was calculated by subtracting the relative rate of each example from 100, where the etching rate of the nickel plate in Comparative Example 1 was taken as 100, and is shown in Table 1. [Evaluation of etching rate and etching inhibition rate of molybdenum plate] The molybdenum plate was etched in the same manner as the tungsten etching method described above, except that a molybdenum plate measuring 2 cm in length, 2 cm in width, and 0.1 mm in thickness was used instead of the tungsten plate, and the etching conditions were changed to an etching temperature of 40° C. and an etching time of 10 minutes, and the etching rate of the molybdenum plate was measured. The results of the etching rate of the molybdenum plate are shown in Table 1. In addition, the etching inhibition rate (%) was calculated by subtracting the relative rate of each example from 100, where the etching rate of the molybdenum plate in Comparative Example 1 was taken as 100, and is shown in Table 1.

[0054] [Gloss rating] The appearance of the tungsten plate, nickel plate and molybdenum plate after etching with each etching solution was visually inspected, and the gloss after etching was evaluated according to the following criteria. The results are shown in Table 1. <Evaluation criteria> 5: The entire board is mirror-finished 4: Most of the plate is mirror-finished, but some corrosion marks are visible. 3: Half of the plate is mirror-finished, but the other half shows signs of corrosion. 2: Most of the board shows signs of corrosion. 1: The entire plate is cloudy and has no mirror finish

[0055] [Table 1]

[0056] As shown in Table 1, the etching solutions of Examples 1 to 13, which contain a water-soluble organic solvent and an etching inhibitor, suppress the decrease in gloss due to etching of a tungsten plate, a nickel plate, and a molybdenum plate, compared to Comparative Example 1, which does not contain a water-soluble organic solvent and an etching inhibitor, and Comparative Examples 2 to 5, which contain a water-soluble organic solvent but no etching inhibitor, and it can be seen that these are etching compositions that are less likely to impair the gloss of a metal film after etching. [Industrial Applicability]

[0057] The etching solution composition of the present disclosure is useful for etching metal films on semiconductor wafers, substrates for liquid crystal displays, substrates for plasma displays, substrates for FEDs (Field Emission Displays), substrates for optical disks, substrates for magnetic disks, substrates for magneto-optical disks, substrates for photomasks, ceramic substrates, and substrates for solar cells, since the gloss of the metal film is not easily impaired after etching.

Claims

1. An etching liquid composition for etching a metal film formed on a substrate, containing phosphoric acid, nitric acid, an organic acid, a water-soluble organic solvent, an etching inhibitor, and water, wherein the metal film is a metal film containing at least one metal selected from tungsten, tantalum, zirconium, hafnium, molybdenum, niobium, ruthenium, osmium, rhenium, rhodium, copper, nickel, cobalt, titanium, titanium nitride, alumina, aluminum, and iridium. The etching liquid composition.

2. The etching liquid composition according to claim 1, wherein the water-soluble organic solvent is at least one of a monoalcohol, a polyhydric alcohol, a glycol ether, a sulfoxide, an amide, an ester, a ketone, and an ether.

3. The etching liquid composition according to claim 1, wherein the etching inhibitor is an organic amine compound.

4. The etching liquid composition according to claim 1, wherein the etching inhibitor is at least one organic amine compound selected from polyalkyleneimine, a polymer containing a structural unit derived from diallylamine, polyalkylene polyamine, and an amino acid.

5. The etching liquid composition according to claim 1, wherein the organic acid is at least one selected from formic acid, acetic acid, propionic acid, butyric acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, maleic acid, fumaric acid, phthalic acid, trimellitic acid, hydroxyacetic acid, lactic acid, salicylic acid, malic acid, tartaric acid, citric acid, aspartic acid, and glutamic acid.

6. The etching liquid composition according to claim 1, wherein the blending amount of the water-soluble organic solvent is 0.1% by mass or more and 50% by mass or less.

7. The mass ratio of the blending amount of the water-soluble organic solvent to the blending amount of the etching inhibitor (water-soluble organic solvent / etching inhibitor) is 0.02 or more and 5000 or less. The etching liquid composition according to claim 1.

8. The etching liquid composition according to claim 1, which does not contain hydrogen peroxide.

9. An etching method comprising a step of etching a metal film containing at least one kind of metal using the etching liquid composition according to any one of claims 1 to 8.

10. A step of etching a metal film formed on a substrate using the etching liquid composition according to any one of claims 1 to 8 is included, The substrate is at least one kind of substrate selected from a semiconductor wafer, a substrate for a liquid crystal display device, a substrate for a plasma display, a substrate for an FED (Field Emission Display), a substrate for an optical disk, a substrate for a magnetic disk, a substrate for a magneto-optical disk, a substrate for a photomask, a ceramic substrate, and a substrate for a solar cell. A substrate processing method.