Filtration method for etchant composition

Abstract

To provide a filtration method for an etchant composition that improves filtration speed while suppressing a change in concentration of components contained in the etchant composition even after filtration at a temperature of 30°C or higher, a manufacturing method and an etching method.SOLUTION: The filtration method includes the step for filtering at a temperature of 30°C or higher an etchant composition for etching a metal film formed on a substrate. The etchant composition contains phosphoric acid, nitric acid, organic acid whose solubility in water at 20°C is equal to or less than 900 g / L, etching inhibitor, and water. The blending amount of the organic acid in the etchant composition is equal to or greater than 10 mass% and equal to or less than 70%. The filtration system includes a tank 1 for storing the etchant composition, a pump 2 for pumping the etchant composition, a filter 3 for filtering the etchant composition, an outlet valve 4 for controlling the flow rate discharged from an outlet 5, a piping P1 connecting the above parts, a circulation route P2 branching from the piping and connecting upstream of the pump, and a circulation valve 7 for controlling the flow rate of the etchant composition being circulated.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a method for filtering an etching solution composition, a method for producing an etching solution composition, and an etching method. [Background technology]

[0002] In the manufacturing process of a semiconductor device, a process is performed in which a film to be etched, which contains at least one metal such as tungsten, tantalum, zirconium, hafnium, molybdenum, niobium, ruthenium, osmium, rhenium, rhodium, copper, nickel, cobalt, titanium, titanium nitride, alumina, aluminum, and iridium, is etched into a predetermined pattern shape. As an etching solution, a mixed acid solution containing phosphoric acid, nitric acid, and acetic acid is generally used. 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 resulted in increased demands for pattern processing techniques and etching solutions, and various etching solution compositions have been proposed.

[0003] For example, Patent Document 1 proposes an etching solution composition containing phosphoric acid, nitric acid, methoxyacetic acid, and water as an etching solution composition for etching a metal thin film containing silver as a main component. Patent Document 2 proposes an etching solution composition for etching a metal oxide containing indium or a metal oxide containing zinc and indium, the etching solution composition containing at least one kind of basic acid (phosphoric acid, nitric acid, etc.) and water, in which the acid dissociation constant pKa at 25°C in any of the dissociation stages of the basic acid is 2.15 or less and the hydrogen ion concentration pH at 25°C is 4 or less. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2006-253473 A [Patent Document 2] JP 2015-60937 A Summary of the Invention [Problem to be solved by the invention]

[0005] If foreign matter is present in the etching solution composition, the cleanliness of the substrate after etching may be deteriorated, and therefore the etching solution composition is usually filtered before use. When the viscosity of the etching solution is high, the filtration speed is slow and the productivity is low, but the viscosity of the etching solution can be reduced by increasing the filtration temperature. However, if the etching solution contains a compound that is easily volatile, such as acetic acid, the compound is volatilized by filtration at high temperatures, changing the concentration, making it difficult to maintain the etching solution composition as originally designed. If the etching solution composition changes, there is a problem that the etching performance cannot be maintained.

[0006] Therefore, in one aspect, the present disclosure provides a method for filtering an etching solution composition that can improve the filtration rate while suppressing changes in the concentrations of components contained in the etching solution composition even when the filtration is performed at a temperature of 30° C. or higher. [Means for solving the problem]

[0007] In one aspect, the present disclosure relates to a method for filtering an etching solution composition for etching a metal film formed on a substrate, the method comprising the step of filtering an etching solution composition at a temperature of 30° C. or higher, the etching solution composition containing phosphoric acid, nitric acid, an organic acid having a solubility in water at 20° C. of 900 g / L or less, an etching inhibitor, and water, and the amount of the organic acid in the etching solution composition is 10 mass% or more and 70 mass% or less.

[0008] In one aspect, the present disclosure relates to a method for producing an etching solution composition for etching a metal film formed on a substrate, the method comprising: filtering an etching solution composition at a temperature of 30° C. or higher; the etching solution composition contains phosphoric acid, nitric acid, an organic acid having a solubility in water at 20° C. of 900 g / L or less, an etching inhibitor, and water; and an amount of the organic acid in the etching solution composition is 10 mass % or more and 70 mass % or less.

[0009] In one aspect, the present disclosure relates to an etching method including a step of etching a metal film formed on a substrate using an etching solution composition obtained by filtering at a temperature of 30° C. or higher, the etching solution composition containing phosphoric acid, nitric acid, an organic acid having a solubility in water at 20° C. of 900 g / L or less, an etching inhibitor, and water, and the amount of the organic acid in the etching solution composition is 10 mass% or more and 70 mass% or less. Effect of the Invention

[0010] According to one aspect of the present disclosure, a method for filtering an etching solution composition can be provided that can improve the filtration rate while suppressing changes in the concentrations of components contained in the etching solution composition even when the etching solution composition is filtered at a temperature of 30° C. or higher. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic diagram illustrating one embodiment of a filling system. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] In one aspect, the present disclosure is based on the finding that by using an etching solution containing phosphoric acid, nitric acid, an organic acid having a solubility of 900 g / L or less in water at 20° C., an etching inhibitor, and water, it is possible to improve the filtration rate while suppressing changes in the concentrations of the components contained in the etching solution composition even when filtration is performed at high temperatures (30° C. or higher).

[0013] In one aspect, the present disclosure relates to a method for filtering an etching solution composition (hereinafter also referred to as the "filtration method of the present disclosure"), the method including a step of filtering an etching solution composition for etching a metal film formed on a substrate (hereinafter also referred to as the "pre-filtered etching solution composition of the present disclosure") at a temperature of 30°C or higher (hereinafter also referred to as the "filtration step"), the etching solution composition containing phosphoric acid, nitric acid, an organic acid having a solubility in water at 20°C of 900 g / L or less, an etching inhibitor, and water, and the amount of the organic acid in the etching solution composition is 10 mass% or more and 70 mass% or less. According to the filtration method of the present disclosure, even when filtration is performed at a temperature of 30° C. or higher, the filtration rate can be improved while suppressing changes in the concentrations of the components contained in the etching solution composition.

[0014] Although the details of the mechanism by which the effects of the present disclosure are manifested are not clear, it is presumed as follows. An organic acid having a solubility in water of 900 g / L or less (e.g., methoxyacetic acid) is less likely to volatilize at temperatures of 30° C. or higher than an organic acid having a solubility in water of more than 900 g / L (e.g., acetic acid). In the present disclosure, by using a predetermined amount of an organic acid having a solubility in water of 900 g / L or less, it is believed that the change in concentration of the components contained in the etching solution composition can be suppressed even when filtration is performed at a temperature of 30° C. or higher, and the viscosity of the etching solution composition can be reduced. Furthermore, it is believed that the reduced viscosity of the etching solution composition increases the filtration rate and improves productivity. However, the present disclosure need not be construed as being limited to these mechanisms.

[0015] [Filtration process] The filtering method of the present disclosure includes a step (filtering step) of filtering an etching solution composition for etching a metal film formed on a substrate (the etching solution composition before filtration of the present disclosure) at a temperature of 30° C. or higher. In one or more embodiments, the etching solution composition obtained in the filtering step (the etching solution composition after filtration) can be used for etching as it is.

[0016] In one or more embodiments, the filtration step includes a filtration process using a filter. Examples of the filter include a pleated filter, a depth filter, a filter containing a filter aid, and the like that have been used in the past, and these can be used in combination. From the viewpoint of improving the filtration rate, a pleated filter is preferred, and a combination of a depth filter and a pleated filter is more preferred, and a filter containing a filter may also be combined. In one or more embodiments, when a filter containing a filter aid is used, it is preferable to provide a pleated filter in the latter stage. As the pleated filter, generally, a filter material is formed into a pleated shape (pleats) and made into a hollow cylindrical cartridge type (Advantec Toyo, Nippon Pall, CUNO, Daiwabo, 3M, Entegris, cobetter, etc.) can be used. Pleated filters are different from depth filters that capture particles at each part in the thickness direction, in that the filter material is thin and it is said that the majority of particles are captured on the filter surface, and they are generally characterized by high filtration accuracy. Pleated filters may be used in one stage or multiple stages (for example, arranged in series). Specific examples of depth type filters include bag type filters (Sumitomo 3M, etc.) and cartridge type filters (Advantec Toyo, Nippon Pall, CUNO, Daiwabo, etc.). A depth type filter is a filter characterized in that the pore structure of the filter material is coarse at the inlet side, fine at the outlet side, and becomes finer continuously or stepwise from the inlet side to the outlet side. Thus, large particles in the etching solution composition are collected near the inlet side, and small particles are collected near the outlet side. Examples of the shape of the depth type filter include a bag type and a cartridge type having a hollow cylindrical shape. In addition, a filter material having the above characteristics is simply molded into a pleated shape, and is classified as a depth type filter because it has the function of a depth type filter. The depth type filter may be used in one stage, or may be used in combination in multiple stages (for example, in a direct arrangement), or filters with different pore sizes may be used in multiple stages in descending order of pore size. Furthermore, a bag type and a cartridge type may be used in combination. The filter aid-containing filter is a filter containing a filter aid. Examples of the filter aid include insoluble mineral substances such as silicon dioxide, kaolin, acid clay, diatomaceous earth, perlite, bentonite, and talc. Among the filter aids, silicon dioxide, diatomaceous earth, and perlite are preferred from the viewpoint of improving dispersibility, diatomaceous earth and perlite are more preferred, and diatomaceous earth is even more preferred. The filter aid-containing filter can contain the filter aid on either or both of the filter surface and the inside of the filter.

[0017] The filtration temperature in the filtration step is 30° C. or higher, preferably 35° C. or higher, and more preferably 40° C. or higher, from the viewpoint of improving the filtration rate, and is preferably 80° C. or lower, more preferably 75° C. or lower, and even more preferably 70° C. or lower, from the viewpoint of the volatility of the etching solution composition. More specifically, the filtration temperature is preferably 30° C. or higher and 80° C. or lower, more preferably 35° C. or higher and 75° C. or lower, and even more preferably 40° C. or higher and 70° C. or lower. In the present disclosure, the filtration temperature refers to the temperature of the etching solution composition during filtration.

[0018] The filtration pressure in the filtration step is preferably from 0.1 MPa to 0.5 MPa, more preferably from 0.15 MPa to 0.45 MPa, and even more preferably from 0.2 MPa to 0.4 MPa, from the viewpoint of productivity.

[0019] From the viewpoint of productivity, the filtration rate in the filtration step is set to 0.1 kg / (m 2 ·min) or more is preferable, and 1kg / (m 2 ·min) or more is preferable, and 2kg / (m 2 ·min) or more is more preferable, and from the viewpoint of reducing the number of particles in the liquid, 30 kg / (m 2 ·min) or less is preferable, and 20kg / (m 2 ·min) or less is more preferable, and 15kg / (m 2 More specifically, the filtration rate is 0.1 kg / (m 2 · min) or more 30kg / (m 2 ·min) or less is preferable, and 1kg / (m2 · min) or more 20kg / (m 2 ·min) or less is more preferable, and 2kg / (m 2 ·min) or more than 15kg / (m 2 .minutes) or less is even more preferable. In the present disclosure, the "filtration rate" refers to the weight filtered per unit area per time, and in one or more embodiments, can be adjusted by adjusting the filtration pressure. When multiple filters are used for filtration, the filtration rate refers to the weight filtered per unit area per time calculated from the sum of the areas of all the filters used.

[0020] The filtration method in the filtration step may be a circulation type in which filtration is repeated, or a one-pass type. A batch type in which one-pass type is repeated may also be used. As for the liquid passing method, a pump is preferably used in the circulation type to apply pressure, and in the one-pass type, in addition to using a pump, a pressure filtration method in which the fluctuation range of the filter inlet pressure is small by introducing air pressure or the like into the tank may be used.

[0021] [Pre-filtered etching solution composition] The pre-filtration etching solution composition of the present disclosure contains phosphoric acid, nitric acid, an organic acid having a solubility in water at 20° C. of 900 g / L or less, an etching inhibitor, and water.

[0022] (phosphoric acid) The amount of phosphoric acid in the pre-filtration etching solution composition of the present disclosure is preferably 1% by mass or more, more preferably 3% by mass or more, and even more preferably 5% by mass or more from the viewpoint of improving the etching rate, storage stability, and filtration rate, and is preferably 90% by mass or less, more preferably 70% by mass or less, and even more preferably 60% by mass or less from the viewpoint of improving the filtration rate. More specifically, the amount of phosphoric acid in the pre-filtration etching solution composition of the present disclosure is preferably 1% by mass or more and 90% 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 60% by mass or less.

[0023] (nitric acid) The amount of nitric acid in the pre-filtration etching solution composition of the present disclosure is preferably 0.5% by mass or more, more preferably 1% by mass or more, more preferably 1.5% by mass or more, more preferably 2% by mass or more, more preferably 3% by mass or more, and more preferably 4% by mass or more, and from the viewpoint of reducing etching unevenness, it is preferably 20% by mass or less, more preferably 10% by mass or less, more preferably 7% by mass or less, and more preferably 6% by mass or less. More specifically, the amount of nitric acid in the pre-filtration 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, more preferably 1.5% by mass or more and 7% by mass or less, more preferably 2% by mass or more and 6% by mass or less, more preferably 3% by mass or more and 6% by mass or less, and more preferably 4% by mass or more and 6% by mass or less.

[0024] (organic acid) The organic acid having a solubility of 900 g / L or less in water at 20° C. and contained in the pre-filtration etching solution composition of the present disclosure may be at least one selected from alkoxycarboxylic acids, hydroxy acids, aliphatic polycarboxylic acids, and alkoxyacetic acid esters, from the viewpoints of improving the filtration rate while suppressing changes in the concentrations of the components contained in the etching solution composition. The alkoxycarboxylic acid may, for example, be methoxyacetic acid (solubility: 485 g / L). An example of the hydroxy acid is citric acid (solubility: 592 g / L). An example of the aliphatic polycarboxylic acid is succinic acid (solubility: 58 g / L). The alkoxyacetic acid ester may, for example, be 3-methoxybutyl acetate (solubility: 4.6 g / L). The organic acids having a solubility of 900 g / L or less in water at 20° C. may be used alone or in combination of two or more kinds.

[0025] The amount of the organic acid having a solubility of 900 g / L or less in water at 20 ° C. in the pre-filtration etching solution composition of the present disclosure is 10 mass % or more, preferably 20 mass % or more, more preferably 30 mass % or more, from the viewpoint of suppressing the concentration change of the components contained in the etching solution composition while improving the filtration rate, and is 70 mass % or less, preferably 65 mass % or less, more preferably 60 mass % or less, from the viewpoint of suppressing the concentration decrease rate of the organic acid. More specifically, the amount of the organic acid having a solubility of 900 g / L or less in water at 20 ° C. in the pre-filtration etching solution composition of the present disclosure is 10 mass % or more and 70 mass % or less, preferably 20 mass % or more and 65 mass % or less, more preferably 30 mass % or more and 60 mass % or less. When two or more organic acids having a solubility of 900 g / L or less in water at 20 ° C. are combined, the amount of the organic acid having a solubility of 900 g / L or less in water at 20 ° C. is the total amount of them.

[0026] The total amount of phosphoric acid, nitric acid and organic acid having a solubility of 900 g / L or less in water at 20 ° C. in the pre-filtration etching solution composition of the present disclosure is preferably 70 mass% or more, more preferably 75 mass% or more, and even more preferably 80 mass% or more from the viewpoint of suppressing the concentration change of the components contained in the etching solution composition while improving the filtration rate, and from the same viewpoint, it is preferably 98 mass% or less, more preferably 95 mass% or less, and even more preferably 90 mass% or less. The total amount of phosphoric acid, nitric acid and organic acid having a solubility of 900 g / L or less in water at 20 ° C. in the pre-filtration etching solution composition of the present disclosure is preferably 70 mass% or more and 98 mass% or less, more preferably 75 mass% or more and 95 mass% or less, and even more preferably 80 mass% or more and 90 mass% or less.

[0027] (Etching inhibitor) In one or more embodiments, the etching inhibitor contained in the pre-filtration etching solution composition of the present disclosure is an amine compound having no carboxyl group, and may be at least one selected from polyalkyleneimine and polyalkylenepolyamine. Examples of the polyalkyleneimine include polyethyleneimine (PEI). Examples of the polyalkylenepolyamine include pentaethylenehexamine, diethylenetriamine, triethylenetetramine, and tetraethylenepentamine. The etching inhibitor may be used alone or in combination of two or more.

[0028] When the etching inhibitor is a polyalkyleneimine, the number average molecular weight of the etching inhibitor is preferably 300 or more, more preferably 600 or more, and even more preferably 1,200 or more from the viewpoint of reducing etching unevenness, storage stability, and improving filtration speed, and is preferably 100,000 or less, more preferably 5,000 or less, and even more preferably 3,000 or less from the viewpoint of viscosity. More specifically, the number average molecular weight of the etching inhibitor is preferably 300 or more and 100,000 or less, more preferably 600 or more and 5,000 or less, and even more preferably 1,200 or more and 3,000 or less. When the etching inhibitor is a polyalkylene polyamine, the weight average molecular weight of the etching inhibitor is preferably 50 or more, more preferably 80 or more, and even more preferably 100 or more, from the viewpoints of reducing etching unevenness and maintaining storage stability and filterability, and from the same viewpoints, is preferably 1,000 or less, more preferably 500 or less, and even more preferably 300 or less. More specifically, the weight average molecular weight of the etching inhibitor is preferably 50 or more and 1,000 or less, more preferably 80 or more and 500 or less, and even more preferably 100 or more and 300 or less.

[0029] The average molecular weight of a compound such as an etching inhibitor used in the present disclosure can be measured by gel permeation chromatography (GPC). An example of a method for measuring the average molecular weight of the etching inhibitor of the present disclosure is shown below. <GPC Conditions (Polyalkyleneimine)> Sample solution: Adjusted to a concentration of 0.1 wt% Apparatus / Detector: HLC-8320GPC (Integrated GPC) manufactured by Tosoh Corporation Column: α-M + α-M (manufactured by Tosoh Corporation) Eluent: 0.15 mol / L Na2SO4, 1% CH3COOH / water Column temperature: 40 °C Flow rate: 1.0 mL / min Sample solution injection volume: 100 μL Standard polymer: Pullulan with known molecular weight (Shodex P-5, P-50, P-200, P-800)

[0030] The compounding amount of the etching inhibitor in the pre-filtration etching solution composition of the present disclosure is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, still more preferably 0.5% by mass or more, and from the viewpoints of reducing etching unevenness, storage stability, and improving filtration rate, 10% by mass or less is preferable, 5% by mass or less is more preferable, 3% by mass or less is still more preferable, and 2% by mass or less is still more preferable. More specifically, the compounding amount of the etching inhibitor in the pre-filtration 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, still more preferably 0.5% by mass or more and 3% by mass or less, and still more preferably 0.5% by mass or more and 2% by mass or less. When the etching inhibitor is a combination of two or more kinds, the compounding amount of the etching inhibitor is the total compounding amount thereof.

[0031] (Water) The pre-filtration etching solution composition of the present disclosure contains water in one or more embodiments. Examples of the water contained in the pre-filtration etching solution of the present disclosure include distilled water, ion-exchanged water, pure water, and ultrapure water. The amount of water in the pre-filtration etching solution composition of the present disclosure is preferably 2% by mass or more, more preferably 5% by mass or more, more preferably 7% by mass or more, and more preferably 10% by mass or more from the viewpoint of improving the filtration speed, and from the same viewpoint, it is preferably 35% by mass or less, more preferably 30% by mass or less, more preferably 25% by mass or less, and more preferably 20% by mass or less. More specifically, the amount of water in the pre-filtration etching solution composition of the present disclosure is preferably 2% by mass or more and 35% by mass or less, more preferably 5% by mass or more and 30% by mass or less, more preferably 7% by mass or more and 25% by mass or less, and more preferably 10% by mass or more and 20% by mass or less.

[0032] (Other Ingredients) The pre-filtration etching solution composition of the present disclosure may further contain other components within the scope of the present disclosure, such as inorganic acids other than phosphoric acid and nitric acid, organic acids other than organic acids having a solubility in water at 20° C. of 900 g / L or less, chelating agents, surfactants, solubilizing agents, preservatives, rust inhibitors, bactericides, antibacterial agents, antioxidants, etc. In one or a plurality of embodiments, the pre-filtration etching solution composition of the present disclosure may be a composition containing a combination of an organic acid having a solubility of 900 g / L or less in water at 20° C. and an organic acid having a solubility of 900 g / L or more in water at 20° C. An example of an organic acid having a solubility of 900 g / L or more in water at 20° C. is acetic acid.

[0033] From the viewpoint of reducing etching unevenness, the pre-filtration etching solution composition of the present disclosure preferably does not contain hydrogen peroxide. Here, in one or more embodiments, "does not contain hydrogen peroxide" includes not containing hydrogen peroxide, not containing substantially hydrogen peroxide, or not containing an amount of hydrogen peroxide that affects the etching result. The amount of hydrogen peroxide in the pre-filtration etching solution composition of the present disclosure is not particularly limited, but is preferably less than 1 mass%, more preferably 0.5 mass% or less, even more preferably 0.1 mass% or less, even more preferably 0.01 mass% or less, and even more preferably 0 mass%.

[0034] (viscosity) The viscosity at 60°C of the pre-filtered etching solution composition of the present disclosure is preferably 30 mPa·s or less, more preferably 25 mPa·s or less, and even more preferably 20 mPa·s or less, from the viewpoint of the filtration rate. In the present disclosure, the viscosity of the etching solution composition can be measured using a general-purpose viscometer such as a Brookfield viscometer or an Ubbelohde viscometer, and specifically, can be measured by the method described in the Examples.

[0035] (pH) From the viewpoint of storage stability and reduction of etching unevenness, the pH of the pre-filtration etching solution composition of the present disclosure is preferably 1 or less, more preferably 0 or less, even more preferably less than 0, and even more preferably about -1. The pH of the pre-filtration etching solution composition of the present disclosure can be -5 or more, or -3 or more. In the present disclosure, the pH of the etching solution composition is a value at 25°C, and can be measured using a pH meter, specifically, can be measured by the method described in the Examples.

[0036] [Method of manufacturing pre-filtered etching solution composition] In one or a plurality of embodiments, the pre-filtration etching solution composition of the present disclosure is obtained by blending phosphoric acid, nitric acid, an organic acid having a solubility in water at 20° C. of 900 g / L or less, an etching inhibitor, water, and, if desired, the above-mentioned optional components by a known method.

[0037] [Etching solution composition after filtration] In one or more embodiments, the components and the amounts of the components contained in the post-filtration etching solution composition obtained in the filtration step of the present disclosure (hereinafter also referred to as the "post-filtration etching solution composition of the present disclosure") can be similar to those in the pre-filtration etching solution composition of the present disclosure described above. In the present disclosure, "the amount of each component in the etching solution composition after filtration" refers, in one or a plurality of embodiments, to the amount of each component in the etching solution composition used in the etching step, i.e., at the time when use in the etching treatment is started (at the time of use). In one or more embodiments, the blending amount of each component in the etching solution composition after filtration of the present disclosure can be regarded as the content of each component in the etching solution composition after filtration of the present disclosure. However, when there is an effect of neutralization, the blending amount and the content may differ.

[0038] The viscosity and pH of the post-filtered etchant composition of the present disclosure, in one or more embodiments, can be similar to the pH of the pre-filtered etchant composition described above.

[0039] The embodiment of the post-filtration etching solution composition of the present disclosure may be a so-called one-component type in which all components are premixed and supplied to the market, or may be a so-called two-component type in which components are mixed at the time of use.

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

[0041] [Film to be etched] In one or more embodiments, the film to be etched using the post-filtration etching solution composition of the present disclosure is a metal film containing at least one metal.Here, the metal film is not particularly limited as long as the effect of the present disclosure is exhibited, but for example, the metal film contains 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.In one or more embodiments, the metal film does not contain silver. In one or more embodiments, the post-filtration etching solution composition of the present disclosure is preferably used for etching a metal film (not including silver) containing at least one metal selected from tungsten, tantalum, zirconium, molybdenum, niobium, and nickel, and is preferably used for etching a tungsten film, a molybdenum film, or a nickel film in one or more embodiments. That is, the film to be etched is a tungsten film, a molybdenum film, or a nickel film in one or more embodiments.

[0042] [Method of manufacturing the etching solution composition] In one aspect, the present disclosure relates to a method for producing an etching solution composition (hereinafter also referred to as the "etching solution production method of the present disclosure"), which includes a step of filtering an etching solution composition for etching a metal film formed on a substrate at a temperature of 30° C. or higher (hereinafter also referred to as the "filtering step"), the etching solution composition containing phosphoric acid, nitric acid, an organic acid having a solubility in water at 20° C. of 900 g / L or less, an etching inhibitor, and water, and the amount of the organic acid in the etching solution composition is 10 mass % or more and 70 mass % or less. According to the etching solution production method of the present disclosure, the productivity of the etching solution composition can be improved. In one or a plurality of embodiments, the filtration method and filtration conditions in the filtration step in the etching solution production method of the present disclosure may be the same as those in the filtration step in the filtration method of the present disclosure described above. In one or a plurality of embodiments, the etching solution composition to be filtered in the filtration step in the etching solution production method of the present disclosure is the above-described pre-filtered etching solution composition of the present disclosure.

[0043] In one or more embodiments, the etching solution manufacturing method of the present disclosure may include a step of blending at least phosphoric acid, nitric acid, an organic acid having a solubility of 900 g / L or less in water at 20° C., an etching inhibitor, and water before the filtration step. In the present disclosure, "blending at least phosphoric acid, nitric acid, an organic acid having a solubility of 900 g / L or less in water at 20° C., an etching inhibitor, and water" includes, in one or more embodiments, simultaneously or sequentially mixing phosphoric acid, nitric acid, an organic acid having a solubility of 900 g / L or less in water at 20° C., an etching inhibitor, water, and the optional components described above as necessary. The order of mixing may not be particularly limited. The blending may be performed using a mixer such as a propeller-type agitator, a pump for liquid circulation stirring, a homomixer, a homogenizer, an ultrasonic disperser, and a wet ball mill. In the etching solution production method of the present disclosure, the preferred amount of each component may be the same as the preferred amount of each component in the pre-filtration etching solution composition of the present disclosure described above.

[0044] [Etching method] In one aspect, the present disclosure relates to an etching method (hereinafter also referred to as the "etching method of the present disclosure") that includes a step of etching a metal film formed on a substrate using an etching solution composition obtained by filtering at a temperature of 30° C. or higher (hereinafter also referred to as the "etching step of the present disclosure"). The etching solution composition contains phosphoric acid, nitric acid, an organic acid having a solubility in water at 20° C. of 900 g / L or less, an etching inhibitor, and water, and the amount of the organic acid in the etching solution composition is 10 mass% or more and 70 mass% or less. In one or more embodiments, the etching solution composition used in the etching step of the present disclosure is the filtered etching solution composition described above. According to the etching method of the present disclosure, the productivity of semiconductor substrates can be improved by using an etching solution composition that can improve the filtration rate while suppressing the concentration change of the components contained in the etching solution composition even when filtered at a temperature of 30° C. or higher. In one or more embodiments, the etching method of the present disclosure may include a step of circulating and filtering the etching solution composition. In one or more embodiments, the circulating and filtering step may include a step of subjecting the circulated etching solution composition to the filtering method described above.

[0045] In the etching step of the present disclosure, examples of the etching method include immersion etching and single wafer etching.

[0046] In one or more embodiments, when the film to be etched is a tungsten film, the temperature (etching temperature) of the etching solution composition in the etching step of the present disclosure is, 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. From the same viewpoint, in one or more embodiments, when the film to be etched is a tungsten film, the etching temperature is preferably 0° C. or higher and 150° C. or lower, more preferably 50° C. or higher and 130° C. or lower, and even more preferably 70° C. or higher and 110° C. or lower. In one or more embodiments, when the film to be etched is a molybdenum film, the temperature of the etching solution composition in the etching step of the present disclosure (etching temperature) is, from the viewpoint of 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. From the same viewpoint, in one or more embodiments, when the film to be etched is a molybdenum film, the etching temperature is preferably 0° C. or higher and 80° C. or lower, more preferably 15° C. or higher and 65° C. or lower, and even more preferably 25° C. or higher and 50° C. or lower. In one or more embodiments, when the film to be etched is a nickel film, the temperature of the etching solution composition in the etching step of the present disclosure (etching temperature) is, from the viewpoint of reducing etching unevenness, preferably 0° C. or higher, more preferably 15° C. or higher, even more preferably 30° C. or higher, and preferably 80° C. or lower, more preferably 65° C. or lower, and even more preferably 50° C. or lower. From the same viewpoint, in one or more embodiments, when the film to be etched is a nickel film, the etching temperature is preferably 0° C. or higher and 80° C. or lower, more preferably 15° C. or higher and 65° C. or lower, and even more preferably 30° C. or higher and 50° C. or lower.

[0047] In the etching process of the present disclosure, the etching time can be set to, for example, 1 minute or more and 180 minutes or less.

[0048] In one or a plurality of embodiments, when the film to be etched is a tungsten film, from the viewpoint of improving productivity, the etching rate in the etching step of the present disclosure is preferably 0.0001 mg / min or more, more preferably 0.0005 mg / min or more, and even more preferably 0.001 mg / min or more, and from the viewpoint of reducing etching unevenness, it is preferably 10 mg / min or less, more preferably 1 mg / min or less, and even more preferably 0.1 mg / min or less. In one or a plurality of embodiments, when the film to be etched is a molybdenum film, the etching rate in the etching step of the present disclosure is, from the viewpoint of improving productivity, preferably 0.01 mg / min or more, more preferably 0.03 mg / min or more, and even more preferably 0.05 mg / min or more, and from the viewpoint of reducing etching unevenness, preferably 10 mg / min or less, more preferably 3 mg / min or less, and even more preferably 1 mg / min or less. In one or a plurality of embodiments, when the film to be etched is a nickel film, the etching rate in the etching step of the present disclosure is, from the viewpoint of improving productivity, preferably 0.001 mg / min or more, more preferably 0.005 mg / min or more, and even more preferably 0.01 mg / min or more, and from the viewpoint of reducing etching unevenness, preferably 10 mg / min or less, more preferably 1 mg / min or less, and even more preferably 0.5 mg / min or less.

[0049] In one or a plurality of embodiments, the etching solution composition and the etching method of the present disclosure can be used to etch metals in the manufacturing process of electronic devices, particularly semiconductor wafers. In one or more embodiments, the etching solution composition of the present disclosure and the etching method of the present disclosure can be suitably used for the preparation of at least one type of substrate selected from a semiconductor wafer, a substrate for a liquid crystal display device, a substrate for a plasma display device, a substrate for an FED (Field Emission Display), a substrate for an optical disk, a substrate for a magnetic disk, a substrate for a magneto-optical disk, a substrate for a photomask, a ceramic substrate, and a substrate for a solar cell. That is, in one aspect, the present disclosure relates to a substrate processing method (hereinafter also referred to as the substrate processing method of the present disclosure) which includes a step of etching a metal film formed on a substrate using the etching solution composition of the present disclosure and the etching method of the present disclosure, and the substrate is at least one type of substrate selected from a semiconductor wafer, a substrate for a liquid crystal display device, a substrate for a plasma display device, a substrate for an FED (Field Emission Display), a substrate for an optical disk, a substrate for a magnetic disk, a substrate for a magneto-optical disk, a substrate for a photomask, a ceramic substrate, and a substrate for a solar cell. According to the substrate processing method of the present disclosure, the productivity and yield of semiconductor substrates can be improved by using an etching solution filtered by the filtration method of the present disclosure. In one or a plurality of embodiments, the etching solution composition and the etching method of the present disclosure can be used to etch electrodes in the manufacturing process of electronic devices, particularly semiconductor memories such as nonvolatile memories including NAND flash memories. In one or more embodiments, the etching solution composition and the etching method of the present disclosure can be suitably used for producing a pattern having a three-dimensional structure, thereby making it possible to obtain an advanced device such as a large-capacity memory. The etching solution composition and the etching method of the present disclosure can be used, for example, in an etching method such as that disclosed in JP2020-145412A. EXAMPLES

[0050] The present disclosure will be specifically described below with reference to examples, but the present disclosure is not limited to these examples in any way.

[0051] 1. Preparation of Etching Solution (Examples 1 to 6, Comparative Examples 1 to 2) Phosphoric acid, nitric acid, an organic acid shown in Table 1, an etching inhibitor shown in Table 1, and water were mixed to obtain etching solutions (pH: 0 to -2) of Examples 1 to 6 and Comparative Examples 1 and 2. The amount of each component (mass %, effective amount) in the prepared etching solution is shown in Table 1. The amount of water in Table 1 includes the amount of water contained in the acid aqueous solution, etc.

[0052] The following components were used to prepare the etching solution. Phosphoric acid [Rinkagaku Kogyo Co., Ltd., concentration 85%] Nitric acid [FUJIFILM Wako Pure Chemical Corporation, concentration 70%] Acetic acid [FUJIFILM Wako Pure Chemical Corporation, concentration 100%, solubility in water at 20°C: 1000g / L] Methoxyacetic acid [FUJIFILM Wako Pure Chemical Corporation, concentration 95%, solubility in water at 20°C: 485g / L] Polyethyleneimine [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 (Pure Conti PC-2000VRL type) and subsystem (Macace KC-05H type) manufactured by Kurita Water Industries Ltd.]

[0053] 2. How to measure parameters [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.

[0054] [Viscosity of etching solution] The viscosity of the etching solution was measured using the following viscometer under the following conditions. Device name: TVB-10 viscometer (with thermostatic bath) manufactured by Toki Sangyo Co., Ltd. Rotor: Spindle No. M1, Cord No. 20 Rotation speed: 100 rpm, viscosity value measured after 60 seconds Measurement temperature: 25℃, 60℃

[0055] [Reduction rate of organic acid concentration] Prepare an aqueous solution of organic acid (the remainder is water) containing the same concentration of organic acid as that of each of the prepared etching solution compositions. Then, store the solution in an open system at 60°C for 30 minutes, and measure the weight of the aqueous solution before and after storage. Then, the concentration reduction rate of the organic acid is calculated using the following formula. Concentration reduction rate of organic acid (%) = 100 - (weight of organic acid solution after storage at 60°C for 30 minutes) / initial weight of organic acid solution

[0056] 3.Evaluation of etching solutions [Evaluation of filtration rate (productivity)] Each of the prepared etching solution compositions was filtered under the following conditions using the filtration system shown in FIG. 1, and the filtration rate (productivity) was evaluated based on the following evaluation criteria. 1 includes a tank 1 for storing an etching solution composition, a pump 2 for delivering the etching solution composition, a filter 3 for filtering the etching solution composition, an outlet valve 4 for controlling the flow rate of the etching solution composition discharged from an outlet 5, and a pipe P1 for connecting the tank 1, the pump 2, the filter 3, the outlet valve 4, and the outlet 5, and further includes a circulation path P2 that branches off from the pipe P1 between the filter 3 and the outlet valve 4 and connects to the upstream side of the pump 2. The filling system shown in FIG. 1 further includes a circulation valve 7 for controlling the flow rate of the etching solution composition circulated through the circulation path P2. First, the prepared etching solution composition is placed in a tank 1. Then, the etching solution composition in the tank 1 is pumped by a pump 2 and filtered by a filter 3. The filtered etching solution composition is filled into a container 6. <Conditions and Equipment> Pump 2: Diaphragm pump DP-10BPT (manufactured by Yamada Corporation) Piping P1, P2: Corrugated flexible hose 15A (manufactured by Fluorochemical Co., Ltd.) Filter 3: Fluoroguard FP CWEX010V1 (Entegris, 20 nm) Container 6: 20L container (polyethylene can (color: gray), manufactured by Kodama Plastics Industry) <Condition> Filtration temperature: Listed in Table 1 Filtration time: See Table 1 Filtration pressure: 0.3MPa Filtration flow rate: 0.5~20kg / (m 2 min) Scale: 300 kg of etching solution composition <Evaluation criteria> ○: No problems with productivity or changes in the composition of the etching solution ×: High viscosity and long filtration time, which creates productivity issues [Table 1]

[0057] As shown in Table 1, in Examples 1 to 6, in which an organic acid (methoxyacetic acid) having a solubility in water at 20°C of 900 g / L or less was used in combination with an etching inhibitor, the rate of decrease in the concentration of the organic acid before and after filtration was smaller than in Comparative Examples 1 and 2, in which an organic acid (acetic acid) having a solubility in water at 20°C of more than 900 g / L was used in combination with an etching inhibitor. Also, the viscosity was low and the filtration time was short. Therefore, even when filtration was performed at a temperature of 30°C or higher, it was found that the filtration rate was improved while the change in concentration of the components contained in the etching solution composition was suppressed. [Industrial Applicability]

[0058] The etching solution composition obtained using the filtration method of the present disclosure is useful for etching metal films on 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. [Explanation of symbols]

[0059] 1...tank, 2...pump, 3...filter, 4...outlet valve, 5...outlet, 6...container, 7...circulation valve, P1...piping, P2...piping (circulation path)

Claims

1. The method includes a step of filtering an etching solution composition for etching a metal film formed on a substrate at a temperature of 30° C. or higher, The etching solution composition contains phosphoric acid, nitric acid, an organic acid having a solubility in water at 20° C. of 900 g / L or less, an etching inhibitor, and water; A method for filtering an etching solution composition, wherein a blending amount of the organic acid in the etching solution composition is 10 mass % or more and 70 mass % or less.

2. 2. The filtration method according to claim 1, wherein the metal film is a metal film containing at least one metal selected from tungsten, tantalum, zirconium, hafnium, molybdenum, niobium, ruthenium, osmium, rhenium, rhodium, copper, nickel, cobalt, titanium, titanium nitride, alumina, aluminum, and iridium.

3. The filtration method according to claim 1 or 2, wherein the organic acid is at least one selected from the group consisting of alkoxycarboxylic acids, hydroxy acids, aliphatic polycarboxylic acids, and alkoxyacetic acid esters.

4. The filtration method according to claim 1 or 2, wherein the etching inhibitor is at least one selected from the group consisting of polyalkyleneimines and polyalkylenepolyamines.

5. 3. The filtering method according to claim 1 or 2, wherein the substrate is at least one type of substrate selected from the group consisting of a semiconductor wafer, a substrate for a liquid crystal display device, a substrate for a plasma display, a substrate for an FED (Field Emission Display), a substrate for an optical disk, a substrate for a magnetic disk, a substrate for a magneto-optical disk, a substrate for a photomask, a ceramic substrate, and a substrate for a solar cell.

6. 3. The filtration method according to claim 1, wherein the amount of hydrogen peroxide in the etching solution composition is less than 1 mass%.

7. The method includes a step of filtering an etching solution composition for etching a metal film formed on a substrate at a temperature of 30° C. or higher, The etching solution composition contains phosphoric acid, nitric acid, an organic acid having a solubility in water at 20° C. of 900 g / L or less, an etching inhibitor, and water; The method for producing an etching solution composition, wherein the amount of the organic acid in the etching solution composition is 10 mass % or more and 70 mass % or less.

8. The etching solution composition is filtered at a temperature of 30° C. or higher, and the etching solution composition is used to etch a metal film formed on a substrate. The etching solution composition contains phosphoric acid, nitric acid, an organic acid having a solubility in water at 20° C. of 900 g / L or less, an etching inhibitor, and water; The etching method, wherein the organic acid is present in an amount of 10% by mass or more and 70% by mass or less in the etching solution composition.

9. A method for manufacturing a semiconductor wafer, comprising using the etching method of claim 8.

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