Substrate manufacturing method

Abstract

According to one embodiment of the present invention, a substrate manufacturing method is provided that is capable of suppressing generation of water-insoluble matter and suppressing residues adhering to a substrate.　One embodiment of the present disclosure relates to a substrate manufacturing method, the method including a step 1 and a step 2 described below, wherein the step 1 and the step 2 are consecutively performed. Step 1: A step for etching, with a composition containing phosphoric acid, nitric acid, and an organic acid, a layer to be etched of a substrate having the layer to be etched containing a group 6 element metal. Step 2: A step for cleaning the substrate obtained in step 1 with an acid having a pKa of 4 or less.

Description

Method for manufacturing a substrate

[0001] The present disclosure relates to a method for manufacturing a substrate and a method for processing a substrate after etching.

[0002] In the manufacturing process of semiconductor devices, for example, a step of etching an etched layer containing 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 to process it into a predetermined pattern shape is performed. In recent years, in the semiconductor field, high integration has been progressing, and there is a demand for more complex and finer wiring. The requirements for pattern processing technology and etching solutions are also increasing, and various etching solutions and etching methods have been proposed.

[0003] For example, Japanese Patent Application Laid-Open No. 2022-147744 (Patent Document 1) proposes a chemical solution used for etching a layer containing molybdenum, which is a chemical solution containing a mixed acid and polyethyleneimine, which is an organic amine. The mixed acid contains an inorganic acid, an oxidizing agent, a carboxylic acid, and water, and a chemical solution in which the concentration of polyethyleneimine in the chemical solution is within the range of 0.05 wt% to 10 wt% is proposed. Japanese Patent Application Laid-Open No. 2022-530669 (Patent Document 2) proposes an etching composition capable of selectively etching cobalt, which is a compound of the formula: R1-O-N-R2R3 (where each of R1, R2, and R3 is independently H or Cx-C6 alkyl), at least one unsaturated C3-C 12 carboxylic acid, at least one leveling agent, and water. Paragraph 0059 of the same document describes that the semiconductor substrate after etching may be rinsed with a rinse solvent, and examples of the rinse solvent include alcohols and aqueous rinse agents with a pH > 8.

[0004] This disclosure relates, in one embodiment, to a method for manufacturing a substrate, comprising the following steps 1 and 2, wherein steps 1 and 2 are performed sequentially. Step 1: A step of etching the etchable layer of a substrate having an etchable layer containing a group 6 elemental metal with a composition containing phosphoric acid, nitric acid, and an organic acid. Step 2: A step of washing the substrate obtained in step 1 with an acid having a pKa of 4 or less.

[0005] This disclosure relates to a substrate processing method in one embodiment, comprising a step of cleaning the substrate to be processed with an acid having a pKa of 4 or less (cleaning step), wherein the substrate to be processed is a substrate having a metal layer containing a group 6 elemental metal, which has been etched with a composition containing phosphoric acid, nitric acid, and an organic acid, and the cleaning step is performed immediately after etching the substrate having the metal layer containing the group 6 elemental metal.

[0006] Mixed acid aqueous solutions (strongly acidic aqueous solutions) containing phosphoric acid are commonly used as etching solutions. However, if water washing is performed after etching with an etching solution containing phosphoric acid, nitric acid, and organic acids, water-insoluble substances may precipitate. Such precipitates adhere to the substrate and become residues.

[0007] Therefore, this disclosure provides a method for manufacturing a substrate and a method for processing a substrate that can suppress the generation of water-insoluble substances and suppress the residue adhering to the substrate.

[0008] According to this disclosure, in one embodiment, a method for manufacturing a substrate can be provided that can suppress the generation of water-insoluble substances and suppress the residue adhering to the substrate.

[0009] This disclosure is based on the finding that, in one embodiment, by washing a substrate after etching using a composition containing phosphoric acid, nitric acid, and an organic acid with a specific acid before washing with water, the generation of water-insoluble substances can be suppressed and residue adhering to the substrate can be suppressed.

[0010] This disclosure relates, in one embodiment, to a method for manufacturing a substrate (hereinafter also referred to as "the substrate manufacturing method of this disclosure"), comprising the following steps 1 and 2, wherein steps 1 and 2 are performed sequentially. Step 1: A step of etching the layer to be etched of a substrate having an etchable layer containing a group 6 elemental metal with a composition containing phosphoric acid, nitric acid, and an organic acid (hereinafter also referred to as "etching solution") (hereinafter also referred to as "etching step"). Step 2: A step of washing the substrate obtained in step 1 with an acid having a pKa of 4 or less (hereinafter also referred to as "rinsing solution") (hereinafter also referred to as "washing step").

[0011] Although the detailed mechanism of the effect of this disclosure is not clear, it is presumed to be as follows: In a composition (etching solution) containing phosphoric acid, nitric acid, and organic acid, as etching progresses, the metal dissolved from the etched layer interacts with the compounds present in the etching solution to form a complex. This complex precipitates as a water-insoluble substance when the substrate is washed with water after etching. In this disclosure, it is thought that by washing with an acid with a pKa of 4 or less, which has high solubility for the complex, after etching and before washing with water, the precipitation of water-insoluble substances can be prevented, and residue adhering to the substrate can be suppressed. However, this disclosure does not have to be interpreted as being limited to these mechanisms.

[0012] [Substrate having an etchable layer containing a Group 6 elemental metal] In this disclosure, the etchable layer is, in one or more embodiments, a metal layer containing a Group 6 elemental metal. The metal layer may be a metal layer consisting only of a Group 6 elemental metal, or it may be a metal layer that is an alloy containing a Group 6 elemental metal. As the Group 6 elemental metal, at least one metal selected from tungsten and molybdenum is preferred, for example. As the etchable layer, in one or more embodiments, a tungsten film (layer) or a molybdenum film (layer) is mentioned. In this disclosure, a substrate having an etchable layer containing a Group 6 elemental metal is, in one or more embodiments, a substrate having a metal layer containing a Group 6 elemental metal. As the substrate, in one or more embodiments, at least one substrate selected from semiconductor wafers, liquid crystal display substrates, plasma display substrates, FED (Field Emission Display) substrates, optical disk substrates, magnetic disk substrates, magneto-optical disk substrates, photomask substrates, ceramic substrates, and solar cell substrates is mentioned.

[0013] [Step 1: Etching Step] Step 1 in the substrate manufacturing method of the present disclosure is a step (etching step) in which the layer to be etched of a substrate having an etchable layer containing a Group 6 elemental metal is etched with a composition (etching solution) containing phosphoric acid, nitric acid, and an organic acid.

[0014] Step 1 is, in one or more embodiments, a step of bringing an etching solution into contact with a substrate having an etchable layer containing a Group 6 element metal. Examples of etching methods in Step 1, or methods for bringing an etching solution into contact with a substrate having an etchable layer, include immersion etching and single-wafer etching.

[0015] In one or more embodiments, when the layer to be etched is a tungsten film, the temperature of the etching solution in step 1 (etching temperature) is preferably 0°C or higher, more preferably 50°C or higher, even more preferably 70°C or higher, preferably 150°C or lower, more preferably 130°C or lower, and even more preferably 110°C or lower, from the viewpoint of uniform etching of the layer to be etched. 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 in step 1 (etching temperature) is preferably 0°C or higher, more preferably 15°C or higher, even more preferably 20°C or higher, preferably 80°C or lower, more preferably 65°C or lower, and even more preferably 50°C or lower, from the viewpoint of uniform etching of the layer to be etched. More specifically, in one or more embodiments, when the layer to be etched is a molybdenum film, the etching temperature is preferably 0°C to 80°C, more preferably 15°C to 65°C, and even more preferably 20°C to 50°C.

[0016] In step 1, the etching time, or the time for contacting the substrate having the layer to be etched with the etching solution, can be set to, for example, 1 minute or more and 180 minutes or less.

[0017] [Composition used in Step 1 (etching solution)] In one or more embodiments, the composition (etching solution) used in Step 1 is a composition containing phosphoric acid, nitric acid, and an organic acid. In one or more embodiments, the composition (etching solution) used in Step 1 is a composition further containing water. In one or more embodiments, the composition (etching solution) used in Step 1 is a composition further containing a nitrogen-containing basic compound. The following describes each component contained in the composition used in Step 1 (hereinafter also referred to as "etching solution used in Step 1").

[0018] (Organic Acids in Etching Solution) Examples of organic acids included in the etching solution used in step 1 include at least one selected from 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. From the viewpoint of uniform etching of the layer to be etched, monovalent organic acids having 1 to 10 carbon atoms are preferred as organic acids, monovalent carboxylic acids having 1 to 10 carbon atoms are more preferred, and those containing acetic acid are even more preferred. One type of organic acid may be used alone, or two or more types may be used in combination.

[0019] From the viewpoint of uniform etching of the layer to be etched, the amount of organic acid in the etching solution used in step 1 is preferably 2% by mass or more, more preferably 3% by mass or more, and even more preferably 5% by mass or more. From the same viewpoint, it is preferably 95% by mass or less, more preferably 70% by mass or less, and even more preferably 50% by mass or less. More specifically, the amount of organic acid in the etching solution used in step 1 is preferably 2% by mass or more and 95% by mass or less, more preferably 3% by mass or more and 70% by mass or less, and even more preferably 5% by mass or more and 50% by mass or less. If there is a combination of two or more organic acids, the amount of organic acid is the total amount of those combined. If the organic acid contains acetic acid, the amount of acetic acid used in the etching solution in step 1 is preferably 2% by mass or more, more preferably 3% by mass or more, and even more preferably 5% by mass or more, from the viewpoint of uniform etching of the layer to be etched, and similarly, preferably 95% by mass or less, more preferably 90% by mass or less, even more preferably 88% by mass or less, even more preferably 80% by mass or less, even more preferably 70% by mass or less, even more preferably 50% by mass or less, and even more preferably 10% by mass or less.

[0020] (Phosphoric acid in etching solution) From the viewpoint of uniform etching of the layer to be etched, the amount of phosphoric acid in the etching solution used in step 1 is preferably 5% by mass or more, more preferably 20% by mass or more, and even more preferably 40% by mass or more. From the same viewpoint, it is preferably 90% by mass or less, more preferably 85% by mass or less, and even more preferably 80% by mass or less. More specifically, the amount of phosphoric acid in the etching solution used in step 1 is preferably 5% by mass or more and 90% by mass or less, more preferably 20% by mass or more and 85% by mass or less, and even more preferably 40% by mass or more and 80% by mass or less.

[0021] (Nitric acid in etching solution) From the viewpoint of improving the etching rate, the amount of nitric acid in the etching solution used in step 1 is preferably 0.5% by mass or more, more preferably 1% by mass or more, and even more preferably 2% by mass or more. From the viewpoint of uniform etching of the layer to be etched, it is preferably 20% by mass or less, more preferably 10% by mass or less, and even more preferably 5% by mass or less. More specifically, the amount of nitric acid in the etching solution used in step 1 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 2% by mass or more and 5% by mass or less.

[0022] The total amount of phosphoric acid, nitric acid, and organic acid in the etching solution used in step 1 is preferably 70% by mass or more, more preferably 75% by mass or more, and even more preferably 80% by mass or more, and from the viewpoint of uniform etching of the layer to be etched, it is preferably 100% by mass or less, more preferably 99.9% by mass or less, even more preferably 99% by mass or less, and even more preferably 98% by mass or less. The total amount of phosphoric acid, nitric acid, and organic acid in the etching solution used in step 1 is preferably 70% by mass or more and 100% by mass or less, more preferably 75% by mass or more and 99.9% by mass or less, and even more preferably 80% by mass or more and 99% by mass or less or 80% by mass or more and 98% by mass or less.

[0023] The acid contained in the etching solution used in step 1 is, in one or more embodiments, an acid containing phosphoric acid, nitric acid, and an organic acid, and from the viewpoint of improving the etching rate, it is preferably an acid containing phosphoric acid, nitric acid, and acetic acid, and more preferably a mixed acid consisting of phosphoric acid, nitric acid, and acetic acid. In this disclosure, "mixed acid" is, in one or more embodiments, a mixed acid containing an organic acid, in one or more embodiments, a mixed acid containing phosphoric acid, nitric acid, and an organic acid, in yet another or more embodiments, a mixed acid containing phosphoric acid, nitric acid, and acetic acid, and in yet another or more embodiments, a mixed acid consisting of phosphoric acid, nitric acid, and acetic acid.

[0024] (Nitrogen-containing basic compounds in the etching solution) In one or more embodiments, the etching solution used in step 1 may further contain nitrogen-containing basic compounds. When the etching solution used in step 1 contains nitrogen-containing basic compounds, precipitation of water-insoluble substances becomes particularly pronounced when water washing is performed after step 1. This is thought to be because nitrogen-containing basic compounds readily form composites with metals that dissolve from the etched layer. In the substrate manufacturing method of this disclosure, by performing steps 1 and 2 consecutively, even if the etching solution contains nitrogen-containing basic compounds, the composite formed in step 1 is dissolved by the acid with a pKa of 4 or less used in step 2, and precipitation of water-insoluble substances can be further suppressed. In one or more embodiments, the nitrogen-containing basic compound contained in the etching solution used in step 1 is at least one compound selected from compounds with ethyleneimine as a repeating unit, compounds having repeating units derived from allylamine, and compounds having repeating units derived from diallylamine. The nitrogen-containing basic compound may be one type or a combination of two or more types. Examples of compounds with ethyleneimine as a repeating unit include polyethyleneimine (PEI). Examples of compounds having repeating units derived from allylamine include allylamine hydrochloride polymers and allylamine polymers. Examples of compounds having repeating units derived from diallylamine include diallylamine polymers and diallylamine / sulfur dioxide copolymers. Among these, from the viewpoint of uniform etching of the layer to be etched, the nitrogen-containing basic compound contained in the etching solution used in step 1 is preferably a compound with ethyleneimine as the repeating unit, and more preferably polyethyleneimine (PEI).

[0025] In one or more embodiments, the number-average molecular weight of a compound having ethyleneimine as a repeating unit is preferably 300 or more, more preferably 600 or more, and even more preferably 1,200 or more, from the viewpoint of uniform etching of the layer to be etched, and from the viewpoint of viscosity, it is preferably 100,000 or less, more preferably 10,000 or less, and even more preferably 5,000 or less. More specifically, the number-average molecular weight of a compound having ethyleneimine as a repeating unit is preferably 300 or more and 100,000 or less, more preferably 600 or more and 10,000 or less, and even more preferably 1,200 or more and 5,000 or less. In one or more embodiments, the weight-average molecular weight of a compound having allylamine-derived repeating units is preferably 1,000 or more, more preferably 2,000 or more, even more preferably 3,000 or more, and preferably 50,000 or less, more preferably 10,000 or less, and even more preferably 7,000 or less, from the viewpoint of uniform etching of the layer to be etched. More specifically, the weight-average molecular weight of the compound having repeating units derived from allylamine is preferably 1,000 to 50,000, more preferably 2,000 to 10,000, and even more preferably 3,000 to 7,000. In one or more embodiments, from the viewpoint of uniform etching of the etched layer, the weight-average molecular weight of the compound having repeating units derived from diallylamine is preferably 1,000 or more, more preferably 2,000 or more, even more preferably 3,000 or more, and preferably 50,000 or less, more preferably 10,000 or less, and even more preferably 7,000 or less. More specifically, the weight-average molecular weight of the compound having repeating units derived from diallylamine is preferably 1,000 to 50,000, more preferably 2,000 to 10,000, and even more preferably 3,000 to 7,000.

[0026] An example of a method for measuring the number-average molecular weight or weight-average molecular weight of nitrogen-containing basic compounds in this disclosure is shown below. <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)

[0027] The amount of nitrogen-containing basic compound in the etching solution used in step 1 is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, and still preferably 0.1% by mass or more, from the viewpoint of keeping the etching rate below a certain level. Furthermore, from the viewpoint of keeping the etching rate above a certain level, it is preferably 10% by mass or less, more preferably 5% by mass or less, and still preferably 3% by mass or less. More specifically, the amount of nitrogen-containing basic compound in the etching solution used in step 1 is preferably 0.01% by mass or more and 10% by mass or less, more preferably 0.05% by mass or more and 5% by mass or less, and still preferably 0.1% by mass or more and 3% by mass or less. When there is a combination of two or more nitrogen-containing basic compounds, the amount of nitrogen-containing basic compounds is the total amount of those compounds.

[0028] In one or more embodiments, the etching solution used in step 1 is preferably a composition containing phosphoric acid, nitric acid, acetic acid, and polyethyleneimine. The mass ratio of phosphoric acid to acetic acid (phosphoric acid / acetic acid) in the etching solution used in step 1 is preferably 0.5 or more, more preferably 1 or more, even more preferably 5 or more, and preferably 20 or less, more preferably 15 or less, and even more preferably 12 or less. The mass ratio of phosphoric acid to nitric acid (phosphoric acid / nitric acid) in the etching solution used in step 1 is preferably 5 or more, more preferably 10 or more, even more preferably 15 or more, and preferably 50 or less, more preferably 40 or less, and even more preferably 30 or less. The mass ratio of acetic acid to nitric acid (acetic acid / nitric acid) in the etching solution used in step 1 is preferably 1 or more, more preferably 1.5 or more, even more preferably 2 or more, and preferably 15 or less, more preferably 10 or less, and even more preferably 5 or less. The mass ratio of phosphoric acid to polyethyleneimine in the etching solution used in step 1 (phosphoric acid / polyethyleneimine) is preferably 40 or more, more preferably 50 or more, even more preferably 60 or more, and preferably 200 or less, more preferably 150 or less, and even more preferably 100 or less. The mass ratio of acetic acid to polyethyleneimine in the etching solution used in step 1 (acetic acid / polyethyleneimine) is preferably 1 or more, more preferably 4 or more, even more preferably 5 or more, and preferably 200 or less, more preferably 100 or less, and even more preferably 10 or less. The mass ratio of nitric acid to polyethyleneimine in the etching solution used in step 1 (nitric acid / polyethyleneimine) is preferably 1 or more, more preferably 1.5 or more, even more preferably 2 or more, and preferably 30 or less, more preferably 15 or less, and even more preferably 5 or less.

[0029] (Water in the etching solution) In one or more embodiments, the etching solution used in step 1 may further contain water. Examples of water in the etching solution used in step 1 include distilled water, deionized water, pure water, and ultrapure water. From the viewpoint of uniform etching of the layer to be etched, the amount of water in the etching solution used in step 1 is preferably 0% by mass or more, more preferably 5% by mass or more, and even more preferably 7% by mass or more. From the same viewpoint, it is preferably 30% by mass or less, more preferably 25% by mass or less, and even more preferably 20% by mass or less. More specifically, the amount of water in the etching solution used in step 1 is preferably 0% by mass or more and 30% by mass or less, more preferably 5% by mass or more and 25% by mass or less, and even more preferably 7% by mass or more and 20% by mass or less.

[0030] (Other Components) The etching solution used in Step 1 may further contain other components, to the extent that the effects of this disclosure are not impaired. Examples of other components include inorganic acids other than phosphoric acid and nitric acid, chelating agents, surfactants, solubilizers, preservatives, rust inhibitors, disinfectants, antibacterial agents, antioxidants, etc. In one or more embodiments, the etching solution used in Step 1 may be substantially free of hydrofluoric acid. For example, the content or amount of hydrofluoric acid in the etching solution used in Step 1 is preferably less than 0.1% by mass, more preferably 0.01% by mass or less, and even more preferably 0% by mass (i.e., not included). In one or more embodiments, the etching solution used in Step 1 may be substantially free of hydroxylamine compounds selected from hydroxylamine and hydroxylamine salts. For example, the content or amount of hydroxylamine compounds in the etching solution used in Step 1 is preferably less than 0.001% by mass, and more preferably 0% by mass (i.e., not included).

[0031] The etching solution used in step 1 is obtained in one or more embodiments by compounding phosphoric acid, nitric acid, and organic acid with the above-mentioned optional components (nitrogen-containing basic compounds, other components) in a known manner. The order in which the components for preparing (manufacturing) the etching solution are mixed in this disclosure is not particularly limited. The compounding can be carried out using a mixer such as a propeller-type stirrer, liquid circulation stirring with a pump, homomixer, homogenizer, ultrasonic disperser, and wet ball mill. The preferred amount of each component in the preparation (manufacturing) of the etching solution can be the same as the preferred amount of each component in the etching solution used in step 1 described above.

[0032] In this disclosure, "amount of each component of the etching solution" means, in one or more embodiments, the amount of each component in the etching solution at the time of use in step 1, that is, at the time of use when the etching process begins (at the time of use). In one or more embodiments, the amount of each component in the etching solution used in step 1 can be considered as the content of each component in the etching solution used in step 1. However, if neutralization is involved, the amount of each component and the content may differ.

[0033] The etching solution used in step 1 may be a so-called one-component type, where all components are pre-mixed and supplied to the market, or a so-called two-component type, where the components are mixed at the time of use. An example of a two-component etching solution is one in which water is separated into a first solution and a second solution, and phosphoric acid, nitric acid, an organic acid, and water are contained in either the first solution or the second solution, or in both, and the first solution and the second solution are mixed at the time of use. After the first solution and the second solution are mixed, they may be diluted with water or an acidic aqueous solution as needed. The first solution and the second solution may each contain the above-mentioned optional components (nitrogen-containing basic compounds, other components) as needed.

[0034] The pH of the etching solution used in step 1 is preferably 1 or less, more preferably 0 or less, even more preferably less than 0, and even more preferably around -1, from the viewpoint of uniform etching of the layer to be etched. The pH of the etching solution used in step 1 can preferably be -5 or higher, and more preferably -3 or higher. In this disclosure, the pH of the etching solution is the value at 25°C and can be measured using a pH meter, specifically by the method described in the examples.

[0035] The etching solution used in step 1 may be stored and supplied in a concentrated state, to the extent that its storage stability is not compromised. This is preferable because it can reduce manufacturing and transportation costs. This concentrated solution can then be used in the etching process after being appropriately diluted with water or an acidic aqueous solution as needed. The dilution ratio can be, for example, 3 to 100 times.

[0036] [Step 2: Cleaning Step] Step 2 in the substrate manufacturing method of the present disclosure is a step (cleaning step) in which the substrate obtained in Step 1 is cleaned with an acid (rinsing solution) having a pKa of 4 or less.

[0037] Step 2, in one or more embodiments, includes bringing the substrate after Step 1 into contact with a rinsing solution. Examples of cleaning methods in Step 2, or methods for bringing the substrate after Step 1 into contact with the rinsing solution, include immersion cleaning, ultrasonic cleaning, agitation cleaning, spray cleaning, and cleaning using rotation such as a spinner. The above-mentioned cleaning methods may be performed individually or in combination. In Step 2, the temperature of the rinsing solution may be, for example, 0°C to 100°C. In Step 2, the cleaning time for rinsing solution cleaning, or the time for contacting the substrate after Step 1 with the rinsing solution, may be, for example, 10 seconds to 120 minutes. In Step 2, ultrasonic waves may also be irradiated when the rinsing solution and the substrate come into contact. Examples of the ultrasonic irradiation conditions may be 20 to 5000 kHz.

[0038] (Acid with pKa of 4 or less (rinsing solution)) The pKa of the acid used for cleaning in step 2 is preferably 4 or less, preferably 3 or less, more preferably 2 or less, and even more preferably 1 or less, and from the same viewpoint, preferably -12 or more, more preferably -11 or more, and even more preferably -10 or more. More specifically, the pKa of the acid used for cleaning in step 2 is preferably -12 or more and 3 or less, more preferably -11 or more and 2 or less, and even more preferably -10 or more and 1 or less. In this disclosure, if the acid has multiple pKa values, pKa is pKa1 in one or more embodiments.

[0039] In one or more embodiments, the acid with a pKa of 4 or less used in step 2 is preferably at least one of an inorganic acid and an organic acid, from the viewpoint of suppressing the generation of water-insoluble substances. Examples of inorganic acids include at least one selected from hydrofluoric acid (pKa 3.2), hydrochloric acid (pKa -8.0), sulfuric acid (pKa -3.0), and phosphoric acid (pKa 2.2). Examples of organic acids include at least one selected from methanesulfonic acid (pKa -2.6), citric acid (pKa 3.1), tartaric acid (pKa 2.89), and lactic acid (pKa 3.86). In one or more embodiments, from a similar viewpoint, the acid with a pKa of 4 or less in step 2 is preferably at least one selected from hydrofluoric acid, hydrochloric acid, sulfuric acid, phosphoric acid, methanesulfonic acid, and citric acid, and more preferably at least one selected from hydrochloric acid, sulfuric acid, phosphoric acid, and citric acid. The acid with a pKa of 4 or less used for washing in step 2 may be one type or a combination of two or more types.

[0040] In one or more embodiments, the acid (rinsing solution) used for cleaning in step 2 is an aqueous acid solution containing an acid with a pKa of 4 or less in an amount of 0.01% by mass or more and 85% by mass or less. In one or more embodiments, the aqueous acid solution is an aqueous solution obtained by mixing an acid with a pKa of 4 or less with water. Examples of water contained in the aqueous acid solution include distilled water, deionized water, pure water, and ultrapure water. In one or more embodiments, from the viewpoint of suppressing the generation of water-insoluble matter, the amount of acid with a pKa of 4 or less in the aqueous acid solution is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and still preferably 1% by mass or more. From the viewpoint of viscosity, it is preferably 85% by mass or less, more preferably 70% by mass or less, and still preferably 60% by mass or less. More specifically, the amount of acid with a pKa of 4 or less in the aqueous acid solution is preferably 0.01% by mass or more and 85% by mass or less, more preferably 0.1% by mass or more and 70% by mass or less, and still preferably 1% by mass or more and 60% by mass or less. When there is a combination of two or more acids with a pKa of 4 or less, the amount of acids with a pKa of 4 or less is the total amount of those acids. In one or more embodiments, the amount of acids with a pKa of 4 or less in the acidic aqueous solution can be considered as the content of acids with a pKa of 4 or less in the acidic aqueous solution. When the acid with a pKa of 4 or less in step 2 is phosphoric acid, the amount of phosphoric acid in the acidic aqueous solution is preferably 5% by mass or more and 85% by mass or less in one or more embodiments, from a similar viewpoint.

[0041] In one or more embodiments, the acid (rinsing solution) used in step 2 preferably does not contain any components other than an acid with a pKa of 4 or less and water. In one or more embodiments, the acid (rinsing solution) used in step 2 substantially does not contain nitrogen-containing basic compounds. For example, the amount of nitrogen-containing basic compounds in the acid (rinsing solution) 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., not included). In one or more embodiments, the acid (rinsing solution) used in step 2 substantially does not contain nitric acid. For example, the amount of nitric acid in the acid (rinsing solution) is preferably less than 0.5% by mass, more preferably 0.1% by mass or less, and even more preferably 0% by mass (i.e., not included). In one or more embodiments, the acid (rinsing solution) used in step 2 substantially does not contain an oxidizing agent. The amount of oxidizing agent in the acid (rinse solution) used in step 2 is preferably 1% by mass or less, more preferably 0.5% by mass or less, even more preferably 0.1% by mass or less, and even more preferably 0% by mass (i.e., not included).

[0042] In step 2, the etching rate of the metal containing the Group 6 element metal is preferably 10 μm / min or less, more preferably 1 μm / min or less, and even more preferably 0.1 μm / min or less. In step 2, the metal containing the Group 6 element metal is not substantially etched. Therefore, in one or more embodiments, the acid (rinsing solution) used in step 2 does not substantially etch the metal layer (i.e., the metal layer containing the Group 6 element metal) that the substrate has after step 1.

[0043] In the substrate manufacturing method of this disclosure, steps 1 and 2 are performed continuously. Performing them continuously means, in one or more embodiments, that there is no step of washing the substrate obtained in step 1 with water between step 1 and step 2. Performing them continuously means, in one or more embodiments, that there is no step of washing the substrate obtained in step 1 with alkali between step 1 and step 2.

[0044] In one or more embodiments, the substrate manufacturing method of the present disclosure may further include a step of washing the substrate after step 2 with water (step 3). In one or more embodiments, step 3 includes bringing the substrate after step 2 into contact with water. Examples of the method of bringing the substrate after step 2 into contact with water include, for example, a method of immersing the substrate in a tank filled with water for contact, a method of spraying water onto the substrate in a spray form for contact, and the like. The time for bringing the substrate into contact with water is preferably, for example, 10 seconds or more and 120 minutes or less. In one or more embodiments, step 3 includes drying the substrate after washing with water (the substrate after contact with water). Examples of the drying method include, for example, air blow drying and the like. [[ID= '2']]

[0045] [Method for Processing Substrate] In one aspect, the present disclosure relates to a method for processing a substrate, including a step of washing the substrate to be processed with an acid having a pKa of 4 or less (washing step), wherein the substrate to be processed is a substrate having a metal layer containing a Group 6 element metal after being etched with a composition containing phosphoric acid, nitric acid, and an organic acid, and the washing step is continuously performed after etching. (Hereinafter, also referred to as "the substrate processing method of the present disclosure").

[0046] In the present disclosure, the substrate processing method is, in one or more embodiments, a method for washing a substrate. That is, the substrate processing method of the present disclosure is, in one or more embodiments, a method for washing a substrate, including a step of washing the substrate to be processed with an acid (rinsing solution) having a pKa of 4 or less (washing step). The washing step in the substrate processing method of the present disclosure corresponds to step 2 in the substrate manufacturing method of the present disclosure described above in one or more embodiments. In one or more embodiments, the washing method and washing conditions in the washing step in the substrate processing method of the present disclosure can be the same as the washing method and washing conditions in step 2 of the substrate manufacturing method of the present disclosure described above.

[0047] In the substrate processing method of the present disclosure, in one or more embodiments, the substrate having a metal layer containing a Group 6 element metal is the substrate after being etched with a composition (etching solution) containing phosphoric acid, nitric acid, and an organic acid. The substrate to be processed is, in one or more embodiments, the substrate after Step 1 in the substrate manufacturing method of the present disclosure described above.

[0048] In the substrate processing method of the present disclosure, the cleaning step is performed continuously after the etching of the substrate having a metal layer containing the Group 6 element metal. In one or more embodiments, the substrate processing method of the present disclosure does not include a step of washing the substrate to be processed with water after etching and before the cleaning step. In one or more embodiments, the substrate processing method of the present disclosure does not include a step of washing the substrate to be processed with an alkali after etching and before the cleaning step.

[0049] In one or more embodiments, the substrate processing method of the present disclosure may further include a step of washing the substrate after the cleaning step with water (water washing step). In one or more embodiments, the water washing step includes bringing the substrate after the cleaning step (the substrate after being washed with an acid having a pKa of 4 or less) into contact with water. Examples of the method of bringing the substrate after the cleaning step into contact with water include, for example, a method of immersing the substrate in a tank filled with water to bring them into contact, a method of ejecting water in a spray form onto the substrate to bring them into contact, etc. The time for bringing the substrate into contact with water is preferably, for example, 10 seconds or more and 120 minutes or less. In one or more embodiments, the water washing step includes drying the substrate after water washing (the substrate after contact with water). Examples of the drying method include, for example, air blow drying.

[0050] The substrate processing method of this disclosure can be suitably used in the fabrication of semiconductor wafers in one or more embodiments. The substrate manufacturing method and substrate processing method of this disclosure can be suitably used in the fabrication of patterns having a three-dimensional structure in one or more embodiments. This makes it possible to obtain advanced devices such as high-capacity memory. The substrate manufacturing method and substrate processing method of this disclosure can be used in the manufacturing process of semiconductor memory such as electrode wiring used in electronic devices, particularly semiconductor devices such as liquid crystal display devices, and non-volatile memory including 3D-NAND flash memory, in one or more embodiments. The substrate manufacturing method and substrate processing method of this disclosure can be suitably used in the formation of single-layer metal wiring and the fabrication of multilayer metal wiring in one or more embodiments. This makes it possible to give the cross-sectional shape of the wiring side surface a good forward taper shape.

[0051] This disclosure further relates to one or more embodiments described below. <1> A method for manufacturing a substrate, comprising the following steps 1 and 2, wherein steps 1 and 2 are performed sequentially: Step 1: Etching the etchable layer of a substrate having an etchable layer containing a group 6 elemental metal with a composition containing phosphoric acid, nitric acid, and an organic acid. Step 2: Washing the substrate obtained in step 1 with an acid having a pKa of 4 or less. <2> The method according to <1>, wherein the composition used in step 1 is a composition further containing water. <3> The method according to <1> or <2>, wherein the composition used in step 1 is a composition further containing a nitrogen-containing basic compound. <4> The method according to any one of <1> to <3>, wherein the acid having a pKa of 4 or less in step 2 is at least one of an inorganic acid and an organic acid. <5> The method according to any one of <1> to <4>, wherein the acid having a pKa of 4 or less in step 2 is at least one selected from hydrochloric acid, sulfuric acid, phosphoric acid, and citric acid. <6> The manufacturing method according to any one of <1> to <5>, wherein the organic acid contained in the composition used in step 1 is a monovalent carboxylic acid having 1 to 10 carbon atoms. <7> The manufacturing method according to any one of <1> to <6>, wherein the amount of organic acid in the composition used in step 1 is 2% by mass or more, or 3% by mass or more, or 5% by mass or more, and 95% by mass or less, or 70% by mass or less, or 50% by mass or less. <8> The manufacturing method according to any one of <1> to <7>, wherein the amount of phosphoric acid in the composition used in step 1 is 5% by mass or more, or 20% by mass or more, or 40% by mass or more, and 90% by mass or less, or 85% by mass or less, or 80% by mass or less. <9> The manufacturing method according to any one of <1> to <8>, wherein the amount of nitric acid in the composition used in step 1 is 0.5% by mass or more, or 1% by mass or more, or 2% by mass or more, and 20% by mass or less, or 10% by mass or less, or 5% by mass or less. <10> The manufacturing method according to any one of <1> to <9>, wherein the total amount of phosphoric acid, nitric acid, and organic acid in the composition used in step 1 is 70% by mass or more, or 75% by mass or more, or 80% by mass or more, and 100% by mass or less, or 99.9% by mass or less, or 99% by mass or less, or 98% by mass or less.<11> The manufacturing method according to any one of <3> to <10>, wherein the nitrogen-containing basic compound contained in the composition used in step 1 is at least one compound selected from compounds having ethyleneimine as a repeating unit, compounds having repeating units derived from allylamine, and compounds having repeating units derived from diallylamine. <12> The manufacturing method according to any one of <3> to <11>, wherein the nitrogen-containing basic compound contained in the composition used in step 1 is polyethyleneimine. <13> The manufacturing method according to <11>, wherein the number average molecular weight of the compound having ethyleneimine as a repeating unit is 300 or more, or 600 or more, or 1,200 or more, and 100,000 or less, or 10,000 or less, or 5,000 or less. <14> The manufacturing method according to <11>, wherein the weight-average molecular weight of the compound having repeating units derived from allylamine is 1,000 or more, or 2,000 or more, or 3,000 or more, and 50,000 or less, or 10,000 or less, or 7,000 or less. <15> The manufacturing method according to <11>, wherein the weight-average molecular weight of the compound having repeating units derived from diallylamine is 1,000 or more, or 2,000 or more, or 3,000 or more, and 50,000 or less, or 10,000 or less, or 7,000 or less. <16> The manufacturing method according to any one of <3> to <15>, wherein the amount of nitrogen-containing basic compound in the composition used in step 1 is 0.01% by mass or more, or 0.05% by mass or more, or 0.1% by mass or more, and 10% by mass or less, or 5% by mass or less, or 3% by mass or less. <17> The manufacturing method according to any one of <1> to <16>, wherein the mass ratio of phosphoric acid to acetic acid (phosphoric acid / acetic acid) in the composition used in step 1 is 0.5 or more, or 1 or more, or 5 or more, and 20 or less, or 15 or less, or 12 or less. <18> The manufacturing method according to any one of <1> to <17>, wherein the mass ratio of phosphoric acid to nitric acid (phosphoric acid / nitric acid) in the composition used in step 1 is 5 or more, or 10 or more, or 15 or more, and 50 or less, or 40 or less, or 30 or less.<19> The manufacturing method according to any one of <1> to <18>, wherein the mass ratio of acetic acid to nitric acid (acetic acid / nitric acid) in the composition used in step 1 is 1 or more, or 1.5 or more, or 2 or more, and 15 or less, or 10 or less, or 5 or less. <20> The manufacturing method according to any one of <3> to <19>, wherein the mass ratio of phosphoric acid to polyethyleneimine (phosphoric acid / polyethyleneimine) in the composition used in step 1 is 40 or more, or 50 or more, or 60 or more, and 200 or less, or 150 or less, or 100 or less. <21> The manufacturing method according to any one of <3> to <20>, wherein the mass ratio of acetic acid to polyethyleneimine (acetic acid / polyethyleneimine) in the composition used in step 1 is 1 or more, or 4 or more, or 5 or more, and 200 or less, or 100 or less, or 10 or less. <22> The manufacturing method according to any one of <3> to <21>, wherein the mass ratio of nitric acid to polyethyleneimine (nitric acid / polyethyleneimine) in the composition used in step 1 is 1 or more, or 1.5 or more, or 2 or more, and 30 or less, or 15 or less, or 5 or less. <23> The manufacturing method according to any one of <1> to <22>, wherein the amount of water in the composition used in step 1 is 0% by mass or more, or 5% by mass or more, or 7% by mass or more, and 30% by mass or less, or 25% by mass or less, or 20% by mass or less. <24> The manufacturing method according to any one of <1> to <23>, wherein the pH of the composition used in step 1 is 1 or less, or 0 or less, or less than 0, or about -1, and -5 or more, or -3 or more. <25> The manufacturing method according to any one of <1> to <24>, wherein the acid used for washing in step 2 is an aqueous acid solution in which the amount of an acid with a pKa of 4 or less is 0.01% by mass or more, or 0.1% by mass or more, or 1% by mass or more, and 85% by mass or less, or 70% by mass or less, or 60% by mass or less. <26> The manufacturing method according to any one of <1> to <25>, wherein the pKa of the acid used for washing in step 2 is 4 or less, or 3 or less, or 2 or less, or 1 or less, and -12 or more, or -11 or more, or -10 or more.<27> The manufacturing method according to any one of <1> to <26>, wherein the Group 6 elemental metal is at least one selected from tungsten and molybdenum. <28> The manufacturing method according to any one of <1> to <27>, wherein performing step 1 and step 2 consecutively means that there is no step of washing the substrate obtained in step 1 with water between step 1 and step 2. <29> A method for processing a substrate, comprising a step of washing the substrate to be processed with an acid having a pKa of 4 or less (washing step), wherein the substrate to be processed is a substrate having a metal layer containing a Group 6 elemental metal after etching with a composition containing phosphoric acid, nitric acid and an organic acid, and the washing step is performed consecutively after etching the substrate having a metal layer containing a Group 6 elemental metal. <30> The substrate processing method according to <29>, wherein the composition further contains water. <31> The substrate processing method according to <29> or <30>, wherein the composition further contains a nitrogen-containing basic compound.

[0052] The present disclosure will be specifically described below with reference to examples, but the present disclosure is not limited in any way by these examples.

[0053] 1. Preparation of Etching Solutions (Examples 1-11, Comparative Examples 1-3) As shown in Table 1, mixed acid (phosphoric acid / acetic acid / nitric acid, mass ratio in etching solution: 75 / 7 / 3), nitrogen-containing basic compound (polyethyleneimine), and water were mixed, and then molybdenum (Mo) powder was added. This was then thoroughly dissolved at 60°C until transparent, to obtain the etching solutions (pH: -1) of Examples 1-11 and Comparative Examples 1-3. The amount of each component (mass %) in each etching solution prepared as described above is shown in Table 1. The amount of water is the residue after subtracting the mixed acid and nitrogen-containing basic compound from the total amount of etching solution (100 mass%). Note that the mass ratio of the mixed acid is calculated on a mass basis, and the amount of water includes the amount of water contained in the acid aqueous solution, etc. The amount of Mo dissolved in the etching solution (ppm) is shown in Table 1. Note that 1 ppm is 0.0001 mass%. The etching solution with added molybdenum powder is intended to be the etching solution after it has been used to etch the molybdenum-containing layer (the etching solution after step 1).

[0054] The following components were used to prepare the etching solution: Phosphoric acid [manufactured by Phosphorus Chemical Industry Co., Ltd., 85% concentration] Nitric acid [manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., 70% concentration] Acetic acid [manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., 100% concentration] Polyethyleneimine (PEI) [number average molecular weight 1,800, "Epomin SP-018" manufactured by Nippon Shokubai Co., Ltd.] Water [ultrapure water produced using a continuous pure water production system (PureConti PC-2000VRL type) and subsystem (MacAce KC-05H type) manufactured by Kurita Water Industries Ltd.] Molybdenum powder ["Mo-3K" manufactured by Nippon Shinkinzoku Co., Ltd.]

[0055] 2. Preparation of Rinse Solution (Examples 1-11, Comparative Examples 1-3) (Examples 1-11, Comparative Examples 2-3) For the rinse solutions of Examples 1-11 and Comparative Examples 2-3, acidic aqueous solutions were obtained by mixing the acids shown in Table 1 with water. The amount of acid (mass%) in the acidic aqueous solutions is as shown in Table 1. (Comparative Example 1) For the rinse solution of Comparative Example 1, water (100 mass%) was used. The rinse solutions of Examples 1-11 and Comparative Examples 1-3 are intended to be rinse solutions used for cleaning the substrate after etching (acidic aqueous solutions or water used for cleaning in step 2).

[0056] The following ingredients were used to prepare the rinse solution: Phosphoric acid [manufactured by Phosphoric Chemical Industry Co., Ltd., 85% concentration] Hydrochloric acid [Fujifilm Wako Pure Chemical Industries, Ltd., 35% concentration] Sulfuric acid [Fujifilm Wako Pure Chemical Industries, Ltd., 96% concentration] Hydrofluoric acid [Sigma-Aldrich, 48% concentration] Methanesulfonic acid [Fujifilm Wako Pure Chemical Industries, Ltd., 98% concentration] Citric acid [Fuso Chemical Industries, Ltd., 50% concentration] Acetic acid [Fujifilm Wako Pure Chemical Industries, Ltd., 100% concentration] Ammonia [29% by mass aqueous ammonia, manufactured by Kanto Chemical Co., Ltd.] Water [Urpure water produced using a continuous pure water production system (PureConti PC-2000VRL model) and subsystem (MacAce KC-05H model) manufactured by Kurita Water Industries Ltd.]

[0057] 3. Method for measuring the pH of the etching solution The pH value of the etching solution at 25°C was measured using a pH meter (manufactured by Toa DKK Co., Ltd.), and the value was obtained one minute after immersing the pH meter electrode in the etching solution.

[0058] 4. Evaluation [Evaluation of Precipitation of Water-Insoluble Matter] 0.2 g of etching solution containing Mo and 1.8 g of acidic aqueous solution were placed in a 9 mL glass bottle and mixed at room temperature (25°C). The mixing ratio of the etching solution and the rinsing solution, i.e., the amount of etching solution / the amount of rinsing solution, was 10% by mass / 90% by mass, as shown in Table 1. After 10 seconds, the presence or absence of precipitate (water-insoluble matter) was visually checked. The results regarding the presence or absence of precipitate are shown in Table 1. In Table 1, "1" is indicated if the presence of precipitate was confirmed, and "0" is indicated if the presence of precipitate was not confirmed.

[0059]

[0060] As shown in Table 1, in Examples 1 to 11, where an aqueous solution of an acid with a pKa of 4 or less was used as the rinsing solution in Step 2, the generation of water-insoluble matter was suppressed. On the other hand, in Comparative Example 1, where water was used as the rinsing solution in Step 2, Comparative Example 2, where an acid with a pKa of 4.6 was used as the rinsing solution in Step 2, and Comparative Example 3, where an acid with a pKa of 9.3 was used as the rinsing solution in Step 2, water-insoluble matter was generated in all of these cases. From these findings, it was concluded that using an acid with a pKa of 4 or less for rinsing a substrate etched with a composition containing phosphoric acid, nitric acid, and organic acids can suppress the generation of water-insoluble matter and reduce the amount of residue adhering to the substrate.

[0061] Furthermore, the following evaluations were performed for Example 2 and Comparative Example 1. [Evaluation of residue after etching] (Example 2) A wafer with molybdenum layers measuring 1 cm vertically and 2 cm horizontally was immersed in the etching solution of Example 2 (phosphoric acid / acetic acid / nitric acid / polyethyleneimine / water = 75 / 7 / 3 / 1 / 14 (mass ratio), Mo dissolution amount 5000 ppm) and etched at 30°C for 15 minutes. After etching, the wafer was continuously immersed in the rinsing solution of Example 2 (5 mass% aqueous phosphoric acid solution) for 5 minutes, then washed with water and dried by air blowing to obtain wafer 1. (Comparative Example 1) A wafer with molybdenum layers measuring 1 cm vertically and 2 cm horizontally was immersed in the etching solution of Comparative Example 1 (phosphoric acid / acetic acid / nitric acid / polyethyleneimine / water = 75 / 7 / 3 / 1 / 14 (mass ratio), Mo dissolution amount 5000 ppm) and etched at 30°C for 15 minutes. After etching, wafer 2 was obtained by washing with the rinse solution (water) of Comparative Example 1, i.e., washing with water only. The surfaces of the obtained wafers 1 and 2 were observed using a scanning electron microscope (S-4800, Hitachi High-Technologies Corporation). As a result, residue was observed in wafer 2, which was washed with water only after etching, whereas no residue was observed in wafer 1, which was washed by a method including immersion in the 5% by mass phosphoric acid aqueous solution after etching. From the above, it was found that by using an acid with a pKa of 4 or less in the rinse solution washing of a substrate etched with a composition containing phosphoric acid, nitric acid, and organic acid, the generation of water-insoluble matter can be suppressed and residue adhering to the substrate can be suppressed.

[0062] This disclosure provides a substrate manufacturing method that can suppress the generation of water-insoluble substances and reduce residue adhering to the substrate, and is useful in the manufacturing of high-capacity semiconductor memory.

Claims

1. A method for manufacturing a substrate, comprising the following steps 1 and 2, wherein steps 1 and 2 are performed sequentially: Step 1: Etching the etchable layer of a substrate having an etchable layer containing a group 6 elemental metal with a composition containing phosphoric acid, nitric acid, and an organic acid. Step 2: Washing the substrate obtained in step 1 with an acid having a pKa of 4 or less.

2. The manufacturing method according to claim 1, wherein the composition used in step 1 is a composition further containing water.

3. The manufacturing method according to claim 1 or 2, wherein the composition used in step 1 is a composition further comprising a nitrogen-containing basic compound.

4. The manufacturing method according to any one of claims 1 to 3, wherein the acid with a pKa of 4 or less in step 2 is at least one of an inorganic acid and an organic acid.

5. The manufacturing method according to any one of claims 1 to 4, wherein the acid with a pKa of 4 or less in step 2 is at least one selected from hydrochloric acid, sulfuric acid, phosphoric acid, and citric acid.

6. The manufacturing method according to any one of claims 1 to 5, wherein the organic acid contained in the composition used in step 1 is a monovalent carboxylic acid having 1 to 10 carbon atoms.

7. The manufacturing method according to any one of claims 1 to 6, wherein the amount of organic acid in the composition used in step 1 is 2% by mass or more and 95% by mass or less.

8. The manufacturing method according to any one of claims 1 to 7, wherein the amount of phosphoric acid in the composition used in step 1 is 5% by mass or more and 90% by mass or less.

9. The manufacturing method according to any one of claims 1 to 8, wherein the amount of nitric acid in the composition used in step 1 is 0.5% by mass or more and 20% by mass or less.

10. The manufacturing method according to any one of claims 1 to 9, wherein the acid used for washing in step 2 is an aqueous acid solution in which the amount of an acid with a pKa of 4 or less is 0.01% by mass or more and 85% by mass or less.

11. The manufacturing method according to any one of claims 3 to 10, wherein the nitrogen-containing basic compound contained in the composition used in step 1 is polyethyleneimine.

12. The manufacturing method according to any one of claims 1 to 11, wherein the Group 6 elemental metal is at least one selected from tungsten and molybdenum.

13. The manufacturing method according to any one of claims 1 to 12, wherein the process of performing step 1 and step 2 consecutively does not include a step of washing the substrate obtained in step 1 with water between step 1 and step 2.

14. A method for processing a substrate, comprising a step of cleaning the substrate to be processed with an acid having a pKa of 4 or less (cleaning step), wherein the substrate to be processed is a substrate having a metal layer containing a group 6 elemental metal, which has been etched with a composition containing phosphoric acid, nitric acid, and an organic acid, and the cleaning step is performed immediately after etching the substrate having the metal layer containing the group 6 elemental metal.

15. The substrate processing method according to claim 14, wherein the composition further comprises water.

16. The substrate processing method according to claim 14 or 15, wherein the composition further comprises a nitrogen-containing basic compound.

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