Etchant composition

Abstract

To provide an etchant composition which can suppress generation of particles in an embodiment.SOLUTION: The present disclosure relates to an etchant composition for etching an etching target layer including at least one type of metal. The etchant composition includes phosphoric acid, a nitrogen-containing basic compound, and water. The content of pyrophosphoric acid in the etchant composition is 50 mass ppm or less.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 step is carried out in which a layer 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 field has seen an increase in integration density, which has led to a demand for more complex and finer wiring. This has led to increasing demands for pattern processing techniques and etching solutions, and various etching methods have been proposed (Patent Documents 1 and 2).

[0003] For example, Patent Document 1 proposes an etching solution composition for etching a layer to be etched that contains at least one kind of metal, the etching solution composition containing an etching inhibitor, an acid containing at least nitric acid, and water, and having a pH of 1 or less, wherein the etching inhibitor is at least one kind of nitrogen-containing compound selected from polymers containing structural units derived from polyalkyleneimine and diallylamine. Patent Document 2 proposes a chemical solution containing mixed acid and polyethyleneimine as a chemical solution used for etching a layer containing molybdenum, the mixed acid containing an inorganic acid, an oxidizing agent, a carboxylic acid, and water, and the concentration of polyethyleneimine in the chemical solution is 0.05 to 10 wt %. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2022-140256 [Patent Document 2] Japanese Patent Publication No. 2022-147744 Summary of the Invention [Problem to be solved by the invention]

[0005] An acid aqueous solution containing phosphoric acid is commonly used as an etching solution. Patent Documents 1 and 2 propose adding a nitrogen-containing compound such as polyethyleneimine to the etching solution as an etching inhibitor, but adding a nitrogen-containing compound to an acid aqueous solution containing phosphoric acid can generate particles in the etching solution. The generated particles can cause a decrease in quality, such as surface residues on the surface of the layer to be etched (metal film surface).

[0006] Therefore, in one aspect, the present disclosure provides an etching solution composition that can suppress the generation of particles. [Means for solving the problem]

[0007] In one aspect, the present disclosure relates to an etching solution composition for etching a layer to be etched that contains at least one metal, the etching solution composition comprising phosphoric acid, a nitrogen-containing basic compound, and water, and a content of pyrophosphoric acid in the etching solution composition being 50 ppm by mass or less.

[0008] In one aspect, the present disclosure relates to an etching solution composition for etching a layer to be etched that contains at least one metal, the etching solution composition comprising phosphoric acid, nitric acid, acetic acid, and water, and a content of pyrophosphoric acid in the etching solution composition being 50 ppm by mass or less.

[0009] In one aspect, the present disclosure relates to an etching solution composition for etching a layer to be etched that contains at least one metal, the etching solution composition comprising phosphoric acid and water, and a content of pyrophosphoric acid in the etching solution composition being 50 ppm by mass or less.

[0010] In one aspect, the present disclosure relates to an etching method including a step of etching a layer to be etched that contains at least one metal using the etching solution composition of the present disclosure.

[0011] In one aspect, the present disclosure relates to an etching method including a step of etching a layer to be etched that contains at least one metal using an etching solution composition containing phosphoric acid, a nitrogen-containing basic compound, and water, the etching method including a step of adjusting the content of pyrophosphoric acid in the etching solution composition used for etching to 50 ppm by mass or less, or a step of confirming that the content of pyrophosphoric acid in the etching solution composition used for etching is 50 ppm by mass or less. [Effects of the Invention]

[0012] According to one aspect of the present disclosure, an etching solution composition capable of suppressing particle generation can be provided. DETAILED DESCRIPTION OF THE INVENTION

[0013] A commercially available aqueous phosphoric acid solution is usually used to prepare an etching solution containing phosphoric acid. As a result of extensive research, the present inventors have found that commercially available aqueous phosphoric acid solutions contain 80 mass ppm or more of pyrophosphoric acid, which reacts with nitrogen-containing compounds to generate particles. Therefore, in one aspect, the present disclosure is based on the finding that the number of particles in the etching solution can be reduced by using an etching solution that contains at least phosphoric acid and has a pyrophosphate content of 50 mass ppm or less.

[0014] In the present disclosure, "particles" refer to particles having a particle diameter of 0.1 μm or more. The number of particles in the etching solution can be measured using a particle counter described in the Examples below. A lower value indicates a smaller number of particles in the etching solution.

[0015] That is, in one aspect, the present disclosure relates to an etching solution composition for etching a layer to be etched that contains at least one kind of metal, the etching solution composition comprising phosphoric acid, a nitrogen-containing basic compound, and water, and a content of pyrophosphoric acid in the etching solution composition being 50 ppm by mass or less (hereinafter also referred to as the "etching solution composition of the present disclosure"). The etching solution composition of the present disclosure can suppress the generation of particles.

[0016] Although the details of the mechanism by which the effects of the present disclosure are manifested are not clear, it is presumed as follows. Pyrophosphoric acid is a component that is generally contained in phosphoric acid aqueous solutions. Under acidic conditions, when pyrophosphoric acid, which has a negative potential, is present with compounds that have a positive potential, including nitrogen-containing compounds such as polyalkylimines and alkylimines, they form ionic bonds to form sparingly soluble aggregates. These sparingly soluble aggregates are thought to then adhere to the substrate as particles, resulting in a deterioration in etching quality. Therefore, in the present disclosure, by removing pyrophosphoric acid from the phosphoric acid aqueous solution and adjusting the content of pyrophosphoric acid in the etching solution composition to 50 ppm by mass or less, it is presumed that the formation of aggregates due to ionic bonding between pyrophosphoric acid and a compound having a positive potential can be suppressed, and particles adhering to the substrate can be reduced, thereby providing an etching solution composition of excellent quality. In addition, the effort required for particle removal treatment can be eliminated. However, the present disclosure need not be construed as being limited to these mechanisms.

[0017] [phosphoric acid] The amount of phosphoric acid blended in the etching solution composition of the present disclosure can be set as appropriate. For example, the amount of phosphoric acid blended can be set as follows depending on the type of nitrogen-containing basic compound contained in the etching solution composition of the present disclosure. When the etching solution composition of the present disclosure contains a polyalkyleneimine as the nitrogen-containing basic compound, the amount of phosphoric acid in the etching solution composition of the present disclosure is preferably 40% by mass or more, more preferably 45% by mass or more, and even more preferably 50% by mass or more from the viewpoint of storage stability, and is preferably 80% by mass or less, more preferably 75% by mass or less, and even more preferably 70% by mass or less from the viewpoint of improving the quality of the layer to be etched. From the same viewpoint, the amount of phosphoric acid in the etching solution composition of the present disclosure is preferably 40% by mass or more and 80% by mass or less, more preferably 45% by mass or more and 75% by mass or less, and even more preferably 50% by mass or more and 70% by mass or less. When the etching solution composition of the present disclosure contains an alkylamine as the nitrogen-containing basic compound, the amount of phosphoric acid in the etching solution composition of the present disclosure is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and even more preferably 1.0% by mass or more, from the viewpoint of improving the quality of the layer to be etched, and is preferably 40% by mass or less, more preferably 20% by mass or less, and even more preferably 10% by mass or less, from the viewpoint of storage stability. From the same viewpoint, the amount of phosphoric acid in the etching solution composition of the present disclosure is preferably 0.1% by mass or more and 40% by mass or less, more preferably 0.5% by mass or more and 20% by mass or less, and even more preferably 1.0% by mass or more and 10% by mass or less. When the etching solution composition of the present disclosure does not contain a nitrogen-containing basic compound, the amount of phosphoric acid in the etching solution composition of the present disclosure is preferably 1 mass % or more from the viewpoint of improving the quality of the layer to be etched, and is preferably 80 mass % or less from the viewpoint of productivity.

[0018] [Pyrophosphate] In one or more embodiments, the etching solution composition of the present disclosure does not contain pyrophosphate, or in one or more embodiments, contains pyrophosphate in an amount of 50 ppm by mass or less. In one or more embodiments, the concentration (content) of pyrophosphate in the etching solution composition of the present disclosure is 50 ppm by mass or less, preferably 40 ppm by mass or less, more preferably 30 ppm by mass or less, even more preferably 20 ppm by mass or less, even more preferably 10 ppm by mass or less, and even more preferably 0 ppm by mass (i.e., not contained), from the viewpoint of suppressing particle generation. In one or more embodiments, the concentration (content) of pyrophosphate in the etching solution composition of the present disclosure is preferably more than 0 ppm, 0.001 ppm or more, or 0.01 ppm or more, from the viewpoint of stability. In one or more embodiments, the concentration (content) of pyrophosphate can be measured by P-NMR, specifically, by the method described in the Examples.

[0019] Here, the method for removing pyrophosphate present in the etching solution composition or the acid aqueous solution is not particularly limited, and examples thereof include a method of adding a salt that insolubilizes pyrophosphate. Examples of salts that insolubilize pyrophosphate include iron chloride. Iron chloride insolubilizes pyrophosphate, thereby reducing the content of pyrophosphate in the etching solution composition or the acid aqueous solution. After removing insolubilized pyrophosphate and salt residues such as iron chloride from the etching solution composition using a filter or the like, the etching solution composition may be used to etch the layer to be etched. Therefore, in one aspect, the present disclosure relates to a method for producing an etching solution composition, which includes a step of removing pyrophosphoric acid from an etching solution composition containing pyrophosphoric acid or an acid aqueous solution (pyrophosphoric acid removal step). In one or more embodiments, the etching solution composition containing pyrophosphoric acid or the etching solution composition of the present disclosure is produced using an aqueous acid solution. In one aspect, the present disclosure relates to an etching solution composition comprising phosphoric acid, a nitrogen-containing basic compound, and water, wherein the etching solution composition is adjusted to have a pyrophosphate concentration of 50 ppm by mass or less through a pyrophosphate removal step, and the content of pyrophosphate in the etching solution composition is 50 ppm by mass or less.

[0020] [Acids other than phosphoric acid] In one or more embodiments, the etching solution composition of the present disclosure may further contain an acid other than phosphoric acid (excluding pyrophosphoric acid) from the viewpoint of productivity. The acid other than phosphoric acid may be used alone or in combination of two or more. From the viewpoint of productivity, the acid other than phosphoric acid preferably includes at least one selected from nitric acid, hydrochloric acid, sulfuric acid, and an organic acid, such as formic acid, acetic acid, methoxyacetic acid, ethoxyacetic 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. Among these, from the viewpoint of productivity, the acid other than phosphoric acid preferably contains nitric acid and an organic acid, more preferably contains at least one selected from nitric acid, acetic acid, methoxyacetic acid, and ethoxyacetic acid, further preferably contains at least one of nitric acid and acetic acid, and further preferably contains a combination of nitric acid and acetic acid. Thus, in one or more other embodiments, the etching solution composition of the present disclosure is an etching solution composition for etching a layer to be etched that contains at least one metal, the etching solution composition comprising phosphoric acid, nitric acid, acetic acid, and water, and a content of pyrophosphoric acid in the etching solution composition being 50 ppm by mass or less.

[0021] <Amount of Acid Other Than Phosphoric Acid> When the etching solution composition of the present disclosure contains an acid other than phosphoric acid (excluding pyrophosphoric acid), the amount of the acid other than phosphoric acid (excluding pyrophosphoric acid) in the etching solution composition of the present disclosure is the total amount of the acids other than phosphoric acid (excluding pyrophosphoric acid) when two or more types of acids other than phosphoric acid are combined. The amount of the acid other than phosphoric acid (excluding pyrophosphoric acid) blended in the etching solution composition of the present disclosure can be set appropriately, and for example, can be set as follows depending on the type of nitrogen-containing basic compound contained in the etching solution composition of the present disclosure. When the etching solution composition of the present disclosure contains a polyalkyleneimine as a nitrogen-containing basic compound, the amount of the acid other than phosphoric acid (excluding pyrophosphoric acid) in the etching solution composition of the present disclosure is preferably 10% by mass or more, more preferably 15% by mass or more, and even more preferably 20% by mass or more, from the viewpoint of improving the quality of the layer to be etched, and is preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 35% by mass or less, from the viewpoint of storage stability. From the same viewpoint, the amount of the acid other than phosphoric acid in the etching solution composition of the present disclosure is preferably 10% by mass or more and 50% by mass or less, more preferably 15% by mass or more and 40% by mass or less, and even more preferably 20% by mass or more and 35% by mass or less. When the nitrogen-containing basic compound contained in the etching solution composition of the present disclosure is an alkylamine, the amount of the acid other than phosphoric acid (excluding pyrophosphoric acid) in the etching solution composition of the present disclosure is preferably 65% by mass or more, more preferably 75% by mass or more, and even more preferably 85% by mass or more from the viewpoint of storage stability, and is preferably 95% by mass or less, more preferably 93% by mass or less, and even more preferably 90% by mass or less from the viewpoint of the quality of the layer to be etched. From the same viewpoint, the amount of the acid other than phosphoric acid in the etching solution composition of the present disclosure is preferably 65% by mass or more and 95% by mass or less, more preferably 75% by mass or more and 93% by mass or less, and even more preferably 85% by mass or more and 90% by mass or less. <Nitric acid blend amount> When the etching solution composition of the present disclosure contains nitric acid as an acid other than phosphoric 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 improving the quality of the layer to be etched, and is preferably 20% by mass or less, more preferably 10% by mass or less, and even more preferably 8% by mass or less from the viewpoint of improving the quality of the layer to be etched. From the same viewpoint, 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 8% by mass or less. <Amount of acetic acid> When the etching solution composition of the present disclosure contains acetic acid as an acid other than phosphoric acid and a polyalkyleneimine as a nitrogen-containing basic compound, the amount of acetic acid in the etching solution composition of the present disclosure is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more, from the viewpoint of improving the quality of the layer to be etched, and is preferably 45% by mass or less, more preferably 35% by mass or less, and even more preferably 30% by mass or less, from the viewpoint of storage stability. From the same viewpoint, the amount of acetic acid in the etching solution composition of the present disclosure is preferably 5% by mass or more and 45% by mass or less, more preferably 10% by mass or more and 35% by mass or less, and even more preferably 15% by mass or more and 30% by mass or less. When the etching solution composition of the present disclosure contains acetic acid as an acid other than phosphoric acid and an alkylamine as a nitrogen-containing basic compound, the amount of acetic acid in the etching solution composition of the present disclosure is preferably 60% by mass or more, more preferably 70% by mass or more, and even more preferably 80% by mass or more from the viewpoint of storage stability, and is preferably 92% by mass or less, more preferably 90% by mass or less, and even more preferably 88% by mass or less from the viewpoint of the quality of the layer to be etched. From the same viewpoint, the amount of acetic acid in the etching solution composition of the present disclosure is preferably 60% by mass or more and 92% by mass or less, more preferably 70% by mass or more and 90% by mass or less, and even more preferably 80% by mass or more and 88% by mass or less.

[0022] The total amount of phosphoric acid and the acid other than phosphoric acid (excluding pyrophosphoric acid) in the etching solution composition of the present disclosure is preferably 70% by mass or more, more preferably 75% by mass or more, and even more preferably 80% by mass or more, from the viewpoint of improving the quality of the layer to be etched.

[0023] [Nitrogen-containing basic compounds] In one or more embodiments, the etching solution composition of the present disclosure contains a nitrogen-containing basic compound. The etching solution composition of the present disclosure is excellent in that it can maintain high etching performance even without containing a nitrogen-containing basic compound, and can maintain a stable state even in the presence of a nitrogen-containing basic compound. This allows for a wider range of third components, such as etching inhibitors and dispersants, to be contained, and also leads to greater freedom in designing the etching solution composition. The nitrogen-containing basic compounds may be used alone or in combination of two or more. In one or more embodiments, the nitrogen-containing basic compound may be at least one selected from alkylamines and polyalkyleneimines from the viewpoint of suppressing etching. In one or more embodiments, the alkylamine may be an alkylamine having from 4 to 24 carbon atoms, such as a primary amine such as dodecylamine. One type of alkylamine may be used, or two or more types may be used in combination. In one or a plurality of embodiments, the polyalkyleneimine may be a polyalkyleneamine having an alkylene group with 2 or more and 5 or less carbon atoms, such as polyethyleneimine (PEI).

[0024] When the nitrogen-containing basic compound is an alkylamine, the molecular weight of the nitrogen-containing basic compound contained in the etching solution composition of the present disclosure is, from the viewpoint of uniform etching of the layer to be etched, preferably 70 or more, more preferably 120 or more, and even more preferably 150 or more, and from the viewpoint of uniform etching of the layer to be etched, preferably 350 or less, more preferably 300 or less, and even more preferably 250 or less. More specifically, the molecular weight of the nitrogen-containing basic compound is preferably 70 or more and 350 or less, more preferably 120 or more and 300 or less, and even more preferably 150 or more and 250 or less. When the nitrogen-containing basic compound is a polyalkyleneimine, the number average molecular weight of the nitrogen-containing basic compound contained in the etching liquid composition of the present disclosure is preferably 300 or more, more preferably 600 or more, still more preferably 1,200 or more, from the viewpoint of etching suppression, and preferably 100,000 or less, more preferably 5,000 or less, still more preferably 3,000 or less, from the viewpoint of improving storage stability. More specifically, the number average molecular weight of the nitrogen-containing basic compound is preferably 300 or more and 100,000 or less, more preferably 600 or more and 5,000 or less, still more preferably 1,200 or more and 3,000 or less.

[0025] In the present disclosure, the number average molecular weight can be measured by gel permeation chromatography (GPC) under the following conditions. <GPC Conditions> 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)

[0026] The amount of the nitrogen-containing basic compound 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 etching suppression and improving the quality of the layer to be etched. From the viewpoint of storage stability, the amount is preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 3% by mass or less. From the same viewpoint, the amount of the nitrogen-containing basic compound 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 two or more nitrogen-containing basic compounds are used in combination, the amount of the nitrogen-containing basic compound is the total amount of the compounds.

[0027] In another aspect, the etching solution composition of the present disclosure may not contain a nitrogen-containing basic compound. Accordingly, in another aspect, the present disclosure relates to an etching solution composition for etching a layer to be etched that contains at least one metal, the etching solution composition comprising phosphoric acid and water, and a content of pyrophosphoric acid in the etching solution composition of 50 mass ppm or less.

[0028] [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 composition of the present disclosure include distilled water, ion-exchanged water, pure water, and ultrapure water. The blending amount of water in the etching liquid composition of the present disclosure is preferably 30% by mass or less, more preferably 25% by mass or less, and even more preferably 20% by mass or less, from the viewpoint of improving the quality of the layer to be etched.

[0029] [Other ingredients] The etching solution composition of the present disclosure may further contain other components, such as chelating agents, surfactants, solubilizing agents, preservatives, rust inhibitors, disinfectants, antibacterial agents, and antioxidants, as long as the effects of the present disclosure are not impaired.

[0030] [Method of manufacturing the etching solution composition] In one or more embodiments, the etching solution composition of the present disclosure can be obtained by blending phosphoric acid, a nitrogen-containing basic compound, water, and, if desired, the optional components described above, using a known method. Accordingly, in one or more embodiments, the present disclosure relates to a method for producing an etching solution composition (hereinafter also referred to as the "method for producing the etching solution composition of the present disclosure"), which includes a step of blending at least phosphoric acid, a nitrogen-containing basic compound, and water. In one or more embodiments, the method for producing an etching solution composition of the present disclosure further includes a step of removing pyrophosphate from an etching solution composition containing phosphoric acid or an acid aqueous solution (the pyrophosphate removal step described above). The removal of pyrophosphate may be carried out so that the pyrophosphate content of the etching solution composition at the time of use is 50 ppm or less. For example, the removal may be carried out during the production of the etching solution composition or immediately before use in an etching process. In the present disclosure, "blending at least phosphoric acid, a nitrogen-containing basic compound, and water" includes, in one or more embodiments, simultaneously or sequentially mixing phosphoric acid, a nitrogen-containing basic compound, water, and, if necessary, the optional components described above. The order of mixing is not particularly limited. The blending can be carried out using a mixer such as a propeller-type agitator, a pump-based liquid circulation agitator, a homomixer, a homogenizer, an ultrasonic disperser, or a wet ball mill. The preferred blending amounts of each component (excluding pyrophosphoric acid) in the method for producing the etching solution composition of the present disclosure can be the same as the preferred blending amounts of each component in the etching solution composition of the present disclosure described above.

[0031] In the present disclosure, the term "amount of each component (excluding pyrophosphoric acid) in the etching solution composition" refers, in one or more embodiments, to the amount of each component of the etching solution composition used in the etching step, i.e., at the time of starting use in the etching treatment (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 considered to be the content of each component in the etching solution composition of the present disclosure. However, if there is an effect of neutralization, the blending amount and the content may differ.

[0032] An embodiment of the etching solution composition of the present disclosure may be a so-called one-component type, in which all components are supplied to the market in a pre-mixed state, or a so-called two-component type, in which components are mixed at the time of use. One embodiment of a two-component etching solution is one that is composed of an acid aqueous solution (first liquid) containing at least phosphoric acid and a solution (second liquid) containing a nitrogen-containing basic compound, and the first and second liquids are mixed at the time of use. After the first and second liquids are mixed, they may be diluted with water or an acid aqueous solution as needed. The first or second liquid may contain all or a part of the water used to prepare the etching solution. The first and second liquids may each contain the optional components described above as needed.

[0033] From the viewpoint of storage stability, the pH of the etching solution composition of the present disclosure is preferably 2 or less, and more preferably 1 or less. In the present disclosure, the pH of the etching solution is a value at 25°C, and can be measured using a pH meter, specifically, by the method described in the Examples.

[0034] The etching solution composition of the present disclosure may be stored and supplied in a concentrated state as long as its stability is not impaired. This is preferable in that production and transportation costs can be reduced. The concentrated solution can then be used in the etching process after being appropriately diluted with water or an aqueous acid solution, as needed. The dilution ratio can be, for example, 5 to 100 times.

[0035] [kit] In one 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 may be a kit (two-component etching solution) that contains an acid aqueous solution (first liquid) containing at least phosphoric acid and a solution (second liquid) containing a nitrogen-containing basic compound in a mutually unmixed state, and that is mixed at the time of use. After the first liquid and the second liquid are mixed, they may be diluted with water or an acid aqueous solution as needed. 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 needed. The kit of the present disclosure allows the preparation of an etching solution composition that can suppress particle generation.

[0036] [Layer to be etched] In one or more embodiments, the layer to be etched using the etching solution composition of the present disclosure is a layer to be etched containing at least one metal. The metal is not particularly limited as long as the effects of the present disclosure are achieved, but examples 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 to etch a layer to be etched containing at least one metal selected from tungsten, molybdenum, niobium, tantalum, and zirconium, and in one or more embodiments, is suitably used to etch a tungsten film or a molybdenum film. That is, in one or more embodiments, the layer to be etched is, for example, a tungsten film or a molybdenum film.

[0037] [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") including a step of etching a layer to be etched that contains at least one metal using an 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, in one or more embodiments, by using the etching solution composition of the present disclosure that can suppress the generation of particles, deterioration in the quality of the surface of the layer to be etched can be suppressed.

[0038] In the etching step of the present disclosure, examples of the etching method include immersion etching and single wafer etching.

[0039] In one or more embodiments, when the layer to be etched is a tungsten film, the temperature of the etching solution composition in the etching step of the present disclosure (etching temperature) is, from the viewpoint of reducing etching unevenness, 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. More specifically, in one or more embodiments, when the layer 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 layer 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 reducing etching unevenness, 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. More specifically, in one or more embodiments, when the layer 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.

[0040] In the etching step of the present disclosure, the etching time can be set to, for example, 1 minute or more and 180 minutes or less. From the viewpoint of improving the quality of the etched layer, it is preferably 15 minutes or more and 90 minutes or less, and more preferably 30 minutes or more and 60 minutes or less.

[0041] In one or more embodiments, when the layer to be etched is a tungsten film, the etching rate in the etching step of the present disclosure is, from the viewpoint of improving productivity, preferably 0.0001 g / min or more, more preferably 0.0005 g / min or more, and even more preferably 0.001 g / min or more, and from the viewpoint of reducing etching unevenness, preferably 10 g / min or less, more preferably 1 g / min or less, and even more preferably 0.1 g / min or less. In one or more embodiments, when the layer to be etched is a molybdenum film, the etching rate in the etching step of the present disclosure is, from the viewpoint of improving productivity, preferably 0.01 g / min or more, more preferably 0.03 g / min or more, and even more preferably 0.05 g / min or more, and from the viewpoint of reducing etching unevenness, preferably 10 g / min or less, more preferably 3 g / min or less, and even more preferably 1 g / min or less.

[0042] In another aspect, the present disclosure relates to an etching method comprising a step of etching a layer to be etched that contains at least one metal using an etching solution composition containing phosphoric acid, nitric acid, acetic acid, and water, the etching method comprising a step of adjusting the content of pyrophosphoric acid in the etching solution composition used for etching to 50 ppm by mass or less, or a step of confirming that the content of pyrophosphoric acid in the etching solution composition used for etching is 50 ppm by mass or less. The etching method of this aspect is also one aspect of the etching method of the present disclosure. In the etching method of this embodiment, the components and contents of the etching composition, the method for measuring pyrophosphate, the method for removing pyrophosphate, the layer to be etched, and the etching method can be the same as those described above.

[0043] In one or more embodiments, the etching liquid composition and 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 and the etching method of the present disclosure can be suitably used in the production of semiconductor wafers, thereby improving the quality of the surface of the layer to be etched and increasing productivity and yield. In one or more 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 enabling the production of advanced devices such as high-capacity memories. 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 JP 2020-145412 A. [Example]

[0044] The present disclosure will be specifically described below using examples, but the present disclosure is not limited to these examples in any way.

[0045] 1. Preparation of Etching Solution The components shown in Table 1 (excluding pyrophosphoric acid) were mixed to obtain etching solutions (pH: -1.5) of Examples 1 to 6 and Comparative Examples 1 to 4. The amount of each component (mass % or mass ppm, active content) in each etching solution is shown in Table 1. The amount of water in Table 1 also includes the amount of water contained in the acid aqueous solution, etc. The etching solutions of Examples 1 to 6 were mixed with an FeCl2 aqueous solution (iron chloride aqueous solution, Fujifilm Wako Pure Chemical Industries, Ltd.) so that the pyrophosphate concentration was the value shown in Table 1, and then filtered through a hydrophilized 50 nm pore size filter (manufactured by Cobetter, material: PTFE (polytetrafluoroethylene)) to remove the mixture of pyrophosphate and Fe. However, the method for reducing the pyrophosphate concentration is not limited to this method. Similarly to Examples 1 to 6, Comparative Examples 1 to 4 were also filtered through a hydrophilized 50 nm pore size filter (manufactured by Cobetter, material: PTFE). The etching solutions of Comparative Examples 1 to 4 contain pyrophosphoric acid, which is contained in commercially available aqueous phosphoric acid solutions.

[0046] The following components were used to prepare the etching solution. (acid) Phosphoric acid [Rinkagaku Kogyo Co., Ltd., concentration 85%] Acetic acid [Fujifilm Wako Pure Chemical Corporation, concentration 100%] Nitric acid [Fujifilm Wako Pure Chemical Corporation, concentration 70%] (Nitrogen-containing basic compound) Polyethyleneimine [number average molecular weight 1800, Nippon Shokubai "SP-018"] Dodecylamine [Tokyo Chemical Industry Co., Ltd.] (water) Water [ultrapure water produced using a continuous pure water production system (Pure Conti PC-2000VRL) and a subsystem (MacAce KC-05H) manufactured by Kurita Water Industries Ltd.]

[0047] [pH of 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.

[0048] [Pyrophosphate concentration in etching solution] The pyrophosphate concentration in the etching solution was measured by P-NMR using a nuclear magnetic resonance apparatus (Avance core 400 MHz, manufactured by Burker) under the following conditions. The results are shown in Table 1. <Measurement conditions> Measuring nucleus: 31P Number of times accumulated: 256 Relaxation time: 5 seconds

[0049] 2.Evaluation of etching solutions [Evaluate particle count] Using a liquid particle counter KS-42AF manufactured by Rion Co., Ltd., each etching solution was measured under the following conditions, and the number of particles per ml was calculated. The results are shown in Table 1. <Measurement conditions> Measurement flow rate: 10ml / min

[0050] [Liquid permeability] A filter with a pore size of 50 nm (manufactured by Cobetter, material: PTFE) was cut to a size of 25φ, hydrophilized, and then attached to a plastic holder manufactured by Advantec. Each etching agent was filtered through the filter for 3 minutes under conditions of 0.2 MPa. The flow rate (g / min) at this time was taken as the liquid permeability value. The liquid permeability values were ranked according to the following evaluation criteria. The results are shown in Table 1. The higher the flow rate, the better the liquid permeability. <Evaluation criteria> A: Flow rate is 12g / min or more B: Flow rate is 10 g / min or more but less than 12 g / min C: Flow rate less than 10g / min

[0051] [Table 1]

[0052] As shown in Table 1, in all of Examples 1 to 6, in which the content of pyrophosphate was 50 ppm by mass or less, the number of particles in the liquid was reduced and the liquid permeability was good compared to Comparative Examples 1 to 4, in which the content of pyrophosphate was more than 50 ppm by mass, and it was therefore considered that the generation of particles was suppressed. [Industrial Applicability]

[0053] The etching solution composition of the present disclosure can suppress particle generation and is useful in a method for manufacturing a large-capacity semiconductor memory.

Claims

1. An etching solution composition for etching a layer to be etched containing at least one metal, comprising: The etching solution composition contains phosphoric acid, a nitrogen-containing basic compound, and water, The etching solution composition, wherein the content of pyrophosphoric acid in the etching solution composition is 50 ppm by mass or less.

2. The etching solution composition according to claim 1 , further comprising an acid other than phosphoric acid (excluding pyrophosphoric acid).

3. 2. The etching solution composition according to claim 1, wherein the acid other than phosphoric acid (excluding pyrophosphoric acid) comprises at least one selected from the group consisting of nitric acid, acetic acid, methoxyacetic acid, and ethoxyacetic acid.

4. 2. The etching solution composition according to claim 1, wherein the metal is at least one metal selected from the group consisting of tungsten, tantalum, zirconium, hafnium, molybdenum, niobium, ruthenium, osmium, rhenium, rhodium, copper, nickel, cobalt, titanium, titanium nitride, alumina, aluminum, and iridium.

5. An etching solution composition for etching a layer to be etched containing at least one metal, comprising: The etching solution composition contains phosphoric acid, nitric acid, acetic acid, and water, The etching solution composition, wherein the content of pyrophosphoric acid in the etching solution composition is 50 ppm by mass or less.

6. An etching solution composition for etching a layer to be etched containing at least one metal, comprising: The etching solution composition contains phosphoric acid and water, The etching solution composition, wherein the content of pyrophosphoric acid in the etching solution composition is 50 ppm by mass or less.

7. An etching method comprising the step of etching a layer to be etched, the layer containing at least one metal, with the etching solution composition according to claim 1 .

8. An etching method comprising a step of etching a layer to be etched, the layer containing at least one metal, using an etching solution composition containing phosphoric acid, a nitrogen-containing basic compound, and water, An etching method comprising a step of adjusting the content of pyrophosphoric acid in an etching solution composition used for etching to 50 ppm by mass or less, or a step of confirming that the content of pyrophosphoric acid in the etching solution composition used for etching is 50 ppm by mass or less.

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