Etching liquid composition

Abstract

The invention provides an etching liquid composition with excellent storage stability in one mode. In one embodiment, the present invention relates to an etchant composition for etching a layer to be etched containing at least one metal, the etchant composition containing nitric acid, a polyamine having a number average molecular weight of 300 or more, a nitrogen-containing basic compound having a molecular weight of less than 300, and water.

Description

Technical Field

[0001] The invention relates to an etching liquid composition and an etching method using the same. Background Art

[0002] In the manufacturing process of semiconductor devices, for example, 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, aluminum oxide, aluminum, and iridium is etched to form a predetermined pattern.

[0003] In recent years, the semiconductor field has been continuously advancing towards high integration, and the industry has required more complex and miniaturized wiring. The requirements for pattern processing technology or etching solutions have also gradually increased, and various etching methods or etching solutions have been proposed.

[0004] For example, Japanese Patent Publication No. 2012-49535 (Patent Document 1) proposes a method that uses an etching solution composition containing 50 to 80 mass % of phosphoric acid, 0.5 to 10 mass % of nitric acid, 5 to 30 mass % of acetic acid, and 0.01 to 5 mass % of imidazole to etch multiple films such as copper / molybdenum (Cu / Mo) stacked metal films at one time.

[0005] Japanese Patent Application Laid-Open No. 2015-144230 (Patent Document 2) proposes a method of etching a titanium-containing layer and a silicon-containing layer using an etching solution containing nitric acid, a fluorine-containing compound, and a nitrogen-containing organic compound A or a phosphorus-containing compound B having a plurality of repeating units containing nitrogen atoms.

[0006] Japanese Patent Application Laid-Open No. 2013-237873 (Patent Document 3) proposes an etching solution for etching a metal film having at least one metal thin film of molybdenum or a molybdenum alloy, and containing phosphoric acid, nitric acid, and a polyalkylene polyamine having three or more amino groups in one molecule.

[0007] Japanese Patent Gazette No. 2022-2324 (Patent Document 4) proposes an etching solution that is suitable for both tungsten-containing metals and tin (TiN)-containing materials, and comprises at least one or more components selected from water, an oxidant, a fluorine-containing etching compound, an organic solvent, a chelating agent, an anti-corrosion agent, and a surfactant. Summary of the invention

[0008] The present invention relates in one embodiment to an etching solution composition for etching a target layer containing at least one metal, the etching solution composition comprising nitric acid, a polyamine having a number average molecular weight of 300 or more, a nitrogen-containing basic compound having a molecular weight of less than 300, and water.

[0009] In one embodiment, the present invention relates to an etching method including the step of etching a layer to be etched containing at least one metal using the etching solution composition of the present invention. DETAILED DESCRIPTION

[0010] As an etching solution, a mixed acid aqueous solution (strong acid aqueous solution) containing phosphoric acid, nitric acid, and acetic acid is generally used. Although Patent Document 2 proposes adding nitrogen-containing organic compounds such as polyethyleneimine (PEI) as an agent for inhibiting etching and improving etching selectivity, if polyethyleneimine is added to the mixed acid aqueous solution, turbidity will occur, and the storage stability of the etching solution will deteriorate. In particular, if it is stored at low temperatures (for example, below 10°C), there is a problem that turbidity is easily generated.

[0011] In view of this, the present invention provides, in one embodiment, an etching solution composition having excellent storage stability and an etching method using the same.

[0012] According to the present invention, in one embodiment, an etching solution composition having excellent storage stability can be provided.

[0013] The inventors of the present invention have conducted intensive research and found that the storage stability can be improved, especially the storage stability at low temperatures (below 10° C.) by using an etching solution containing nitric acid, a polyamine with a number average molecular weight of 300 or more, and a nitrogen-containing basic compound with a molecular weight of less than 300.

[0014] The present invention relates in one embodiment to an etching solution composition (hereinafter also referred to as “the etching solution composition of the present invention”), which is used for etching a layer to be etched containing at least one metal, and the etching solution composition contains nitric acid, a polyamine having a number average molecular weight of 300 or more, a nitrogen-containing basic compound having a molecular weight of less than 300, and water.

[0015] The details of the mechanism by which the effects of the present invention are expressed are not yet clear, but are presumed as follows.

[0016] Polyamines have multiple amino groups in the molecule, and all of these amino groups can form salts with nitric acid in water. Since the solubility of the salt of amino group with nitric acid in water is not that high, the more the number of amino groups that form salts with nitric acid, the lower the solubility in the solution, especially at low temperatures (e.g., below 10°C), the liquid is prone to turbidity. In the present invention, a polyamine with a number average molecular weight of 300 or more and a nitrogen-containing basic compound with a molecular weight of less than 300 are used in combination. As a result, the nitrogen-containing basic compound forms a salt with nitric acid, thereby reducing the amount of nitrate ions and reducing the amount of amino groups that form salts with nitric acid in one molecule of the polyamine. It is believed that the amount of the salt of amino group with nitric acid in one molecule of the polyamine is reduced, and even if stored at low temperatures (e.g., below 10°C), the liquid is less likely to become turbid, which can improve storage stability.

[0017] In addition, it is considered that the etching solution composition of the present invention has a stable composition and therefore can uniformly contact with the layer to be etched and perform uniform etching.

[0018] However, the present invention should not be construed limited to these mechanisms.

[0019] [nitric acid]

[0020] The amount of nitric acid in the etching solution composition of the present invention is preferably 0.5% by mass or more, more preferably 1% by mass or more, and further preferably 1.5% by mass or more from the viewpoint of increasing the etching rate, and is preferably 20% by mass or less, more preferably 10% by mass or less, and further preferably 8% by mass or less from the viewpoint of improving storage stability. More specifically, the amount of nitric acid in the etching solution composition of the present invention 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 further preferably 1.5% by mass or more and 8% by mass or less.

[0021] [Polyamine having a number average molecular weight of 300 or more]

[0022] In one or more embodiments, the polyamine having a number average molecular weight of 300 or more contained in the etching solution composition of the present invention may be a compound having two or more amino groups in the molecule. As the above-mentioned polyamine, in one or more embodiments, from the viewpoint of inhibiting etching, examples include: polyalkylene imine, polymers having structural units derived from compounds having amino groups and ethylenically unsaturated double bonds, and the like. As the above-mentioned polyalkylene imine, for example, polyethylene imine (PEI) and the like can be mentioned, preferably branched polyethylene imine. As the above-mentioned polymer having structural units derived from compounds having amino groups and ethylenically unsaturated double bonds, for example, diallylamine copolymers, diallylamine / sulfur dioxide copolymers, diallyldimethylammonium chloride polymers, and diallyldimethylammonium chloride / sulfur dioxide copolymers can be mentioned. Among them, from the viewpoint of inhibiting etching, as the above-mentioned polyamine, polyalkylene imines such as PEI are preferred. The polyamine having a number average molecular weight of 300 or more can be used alone or in combination of two or more.

[0023] Regarding the number average molecular weight of the polyamine, in one or more embodiments, from the viewpoint of suppressing etching, it is 300 or more, preferably 600 or more, and more preferably 1200 or more, and from the viewpoint of improving storage stability, it is preferably 100000 or less, more preferably 5000 or less, and further preferably 3000 or less. More specifically, the number average molecular weight of the polyamine is preferably 300 or more and 100000 or less, more preferably 600 or more and 5000 or less, and further preferably 1200 or more and 3000 or less.

[0024] In the present invention, the number-average molecular weight can be measured by gel permeation chromatography (GPC) under the following conditions.

[0025] <GPC Conditions>

[0026] Test solution: A test solution adjusted to a concentration of 0.1 wt%

[0027] Apparatus / Detector: HLC-8320GPC (Integrated GPC) manufactured by Tosoh Corporation

[0028] Column: α-M + α-M (manufactured by Tosoh Corporation)

[0029] Eluent: 0.15 mol / L Na2SO4, 1% CH3COOH / water

[0030] Column temperature: 40 °C

[0031] Flow rate: 1.0 mL / min

[0032] Test solution injection volume: 100 μL

[0033] Standard polymer: Amylopectin with known molecular weight (P-5, P-50, P-200, P-800 from Shodex)

[0034] Regarding the blending amount of the polyamine having a number-average molecular weight of 300 or more in the etching solution composition of the present invention, from the viewpoint of improving storage stability, it is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, and further preferably 0.4% by mass or more. Also, from the viewpoint of the liquid permeability during filtration associated with the solution viscosity, it is preferably 20% by mass or less, more preferably 10% by mass or less, and further preferably 5% by mass or less. More specifically, the blending amount of the polyamine having a number-average molecular weight of 300 or more in the etching solution composition of the present invention is preferably 0.1% by mass or more and 20% by mass or less, more preferably 0.2% by mass or more and 10% by mass or less, and further preferably 0.4% by mass or more and 5% by mass or less. In the case of a combination of two or more kinds of the above polyamines, the blending amount of the above polyamines is their total blending amount.

[0035] [Nitrogen-containing basic compound having a molecular weight less than 300]

[0036] The molecular weight of the nitrogen-containing basic compound contained in the etching solution composition of the present invention is, in one or more embodiments, less than 300, preferably 250 or less, and more preferably 200 or less from the viewpoint of improving storage stability, and is preferably 15 or more, more preferably 20 or more, and even more preferably 30 or more from the viewpoint of uniformly etching the etched layer. More specifically, the molecular weight of the nitrogen-containing basic compound is preferably 15 or more and less than 300, more preferably 20 or more and 250 or less, and even more preferably 30 or more and 200 or less.

[0037] In one or more embodiments, the nitrogen-containing basic compound is preferably at least one selected from ammonia, alkylamines, alkanolamines, alicyclic amines, aromatic amines, and polyalkylene polyamines, and more preferably at least one selected from ammonia, alicyclic amines, and polyalkylene polyamines from the viewpoint of improving storage stability.

[0038] Examples of the alkylamine include ethylamine. Examples of the alkanolamine include 2-(2-aminoethylamino)ethanol. Examples of the alicyclic amine include N-(2-hydroxyethyl)piperazine and N-(2-aminoethyl)piperazine. Examples of the aromatic amine include benzotriazole, aminopyrazole, aminopyridine, aminopyrimidine, aminopyrazine, aminooxazole, and thiazolylamine. From the same viewpoint, the polyalkylene polyamine is preferably a polyalkylene polyamine having 2 to 4 amino groups in the molecule, and more preferably at least one selected from alkylenediamine, dialkyltriamine, and trialkylenetetramine. Examples of the alkylenediamine include ethylenediamine. Examples of the dialkyltriamine include diethylenetriamine. Examples of the trialkylenetetramine include triethylenetetramine.

[0039] The nitrogen-containing basic compound having a molecular weight of less than 300 may be used alone or in combination of two or more.

[0040] The amount of the nitrogen-containing basic compound having a molecular weight of less than 300 in the etching solution composition of the present invention is preferably 0.4% by mass or more, more preferably 0.8% by mass or more, and further preferably 1.2% by mass or more from the viewpoint of improving storage stability, and preferably 20% by mass or less, more preferably 15% by mass or less, and further preferably 10% by mass or less from the viewpoint of liquid permeability during filtration associated with solution viscosity. More specifically, the amount of the nitrogen-containing basic compound having a molecular weight of less than 300 in the etching solution composition of the present invention is preferably 0.4% by mass or more and 20% by mass or less, more preferably 0.8% by mass or more and 15% by mass or less, and further preferably 1.2% by mass or more and 10% by mass or less. In the case where the above-mentioned nitrogen-containing basic compound is a combination of two or more kinds, the amount of the above-mentioned nitrogen-containing basic compound is the total amount of these compounds.

[0041] In the present invention, the blending amount (mass %) a of nitric acid, the blending amount (mass %) b of the polyamine having a number average molecular weight of 300 or more, and the blending amount (mass %) c of the nitrogen-containing basic compound having a molecular weight of less than 300 preferably satisfy the relationship (a-c): 4 / b≤600. In one or more embodiments, a and c satisfy the relationship of a<c, a=c, or a>c. It should be noted that a, b, and c each represent mass or mass % (the same below).

[0042] About (a-c) 4 / b, from the viewpoint of improving storage stability and improving storage stability at a temperature below 10°C, is preferably 600 or less, more preferably 550 or less, further preferably 500 or less, further preferably 400 or less, and from the viewpoint of uniformly etching the etched layer, is preferably 0.01 or more, more preferably 0.1 or more, further preferably 0.5 or more, 50 or more, 100 or more, 200 or more, or 300 or more.

[0043] From the same point of view, (a-c) 4 / b is preferably greater than or equal to 0.01 and less than or equal to 600, more preferably greater than or equal to 0.1 and less than or equal to 600, further preferably greater than or equal to 0.5 and less than or equal to 600, further preferably greater than or equal to 50 and less than or equal to 600, further preferably greater than or equal to 100 and less than or equal to 600, further preferably greater than or equal to 200 and less than or equal to 600, further preferably greater than or equal to 300 and less than or equal to 600, further preferably greater than or equal to 300 and less than or equal to 550, further preferably greater than or equal to 300 and less than or equal to 500.

[0044] Here, for (a-c) 4 The reason why / b is preferably 600 or less is as follows.

[0045] As described above, the polyamine has multiple amino groups in the molecule, and all of these amino groups can form salts with nitric acid in water. Whether several amino groups in the molecule of the polyamine form salts with nitric acid depends on the amount of nitrate ions and ammonium ions contained in the etching solution composition. If the amount of the polyamine is increased, the amount of nitrate ions is relatively reduced relative to the amount of ammonium ions, so the amount of amino groups that form salts with nitric acid in one molecule of the polyamine is reduced. If the amount of nitric acid is increased, in addition to the increase in the amount of nitric acid, the pH also decreases significantly, so the amount of nitrate ions in the etching solution composition increases dramatically, and the amount of amino groups that form salts with nitric acid in one molecule of the polyamine increases significantly. It is believed that when a polyamine with a number average molecular weight of 300 or more coexists with a nitrogen-containing basic compound with a molecular weight of less than 300, the nitrogen-containing basic compound forms a salt with nitric acid, so the amount of nitrate ions decreases, and the amount of amino groups that form salts with nitric acid in one molecule of the polyamine is reduced. In addition, the solubility of amines / nitrates in water is not that high, so when the concentration of water is low, the more amino groups that form salts with nitric acid, the lower the solubility in the solution, and the liquid tends to become turbid, especially at low temperatures (e.g., below 10°C). The amount of salt formed depends on the amount of nitrate ions and ammonium ions as described above, which is greatly affected by the amount of nitric acid and the amount of nitrogen-containing basic compounds.

[0046] The inventors of the present invention have carefully examined the influence of the ratio of the amount of nitrate ions to the amount of ammonium ions, and have found that the amount of nitric acid (mass %) a, the amount of polyamine having a number average molecular weight of 300 or more (mass %) b, and the amount of nitrogen-containing basic compound having a molecular weight of less than 300 (mass %) c satisfy the relationship (a-c): 4 When / b≤600, the liquid is less likely to become turbid even when stored at low temperatures (eg, 10° C. or lower), and the storage stability can be further improved.

[0047] Furthermore, it is considered that since the composition is more stable, the etching target layer can be contacted more uniformly, and etching with further reduced etching unevenness can be performed.

[0048] [Acids other than nitric acid]

[0049] From the viewpoint of uniformly etching the etched layer, the etching solution composition of the present invention may further contain an acid other than nitric acid. The acid other than nitric acid may be used alone or in combination of two or more.

[0050] As the acid other than nitric acid, at least one selected from phosphoric acid, hydrochloric acid, sulfuric acid, and organic acid can be cited. As the organic acid, for example, 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, glycolic acid, lactic acid, salicylic acid, malic acid, tartaric acid, citric acid, aspartic acid, and glutamic acid can be cited. Among them, as the acid other than nitric acid, from the viewpoint of uniformly etching the etched layer, preferably at least one selected from phosphoric acid, acetic acid, methoxyacetic acid, and ethoxyacetic acid, more preferably at least one of phosphoric acid and acetic acid, more preferably a combination of phosphoric acid and acetic acid.

[0051] In the case where the etching solution of the present invention further contains an acid other than nitric acid, the amount of the acid other than nitric acid in the etching solution of the present invention is preferably 65% ​​by mass or more, more preferably 70% by mass or more, and further preferably 75% by mass or more, from the perspective of uniformly etching the etched layer, and, from the same perspective, preferably 98% by mass or less, more preferably 95% by mass or less, and further preferably 90% by mass or less. More specifically, the amount of the acid other than nitric acid in the etching solution composition of the present invention is preferably 65% ​​by mass or more and 98% by mass or less, more preferably 70% by mass or more and 95% by mass or less, and further preferably 75% by mass or more and 90% by mass or less. In the case where the types of acids other than nitric acid are a combination of two or more, the amount of the acid other than nitric acid is the total amount of these.

[0052] When the acid other than nitric acid is a combination of phosphoric acid and acetic acid, the amount of phosphoric acid in the etching solution composition of the present invention is preferably 50% by mass or more and 95% by mass or less, more preferably 55% by mass or more and 93% by mass or less, and further preferably 60% by mass or more and 90% by mass or less from the viewpoint of uniformly etching the etched layer. From the same viewpoint, the amount of acetic acid in the etching solution composition of the present invention is preferably 2% by mass or more and 80% by mass or less, more preferably 3% by mass or more and 60% by mass or less, and further preferably 5% by mass or more and 30% by mass or less.

[0053] [water]

[0054] In one or more embodiments, the etching liquid composition of the present invention contains water. Examples of the water contained in the etching liquid composition of the present invention include distilled water, ion-exchanged water, pure water, and ultrapure water.

[0055] The amount of water in the etching solution composition of the present invention is preferably 2% by mass or more, more preferably 5% by mass or more, and further preferably 7% by mass or more from the viewpoint of improving storage stability, and is preferably 30% by mass or less, more preferably 25% by mass or less, and further preferably 20% by mass or less from the viewpoint of uniformly etching the etched layer. More specifically, the amount of water in the etching solution composition of the present invention is preferably 2% by mass or more and 30% by mass or less, more preferably 5% by mass or more and 25% by mass or less, and further preferably 7% by mass or more and 20% by mass or less.

[0056] [Other ingredients]

[0057] The etching solution composition of the present invention may be further formulated with other components within the range that does not impair the effects of the present invention. Examples of other components include chelating agents, surfactants, cosolvents, preservatives, rust inhibitors, bactericides, antibacterial agents, antioxidants, and the like.

[0058] In one or more embodiments, the etching solution composition of the present invention may be substantially free of imidazole. The amount of imidazole in the etching solution composition of the present invention is preferably less than 0.01% by mass, more preferably 0.001% by mass or less, and further preferably 0% by mass (i.e., free of imidazole).

[0059] In one or more embodiments, the etching solution composition of the present invention may be substantially free of fluorine-containing compounds. The amount of fluorine-containing compounds in the etching solution composition of the present invention is preferably less than 0.001% by mass, more preferably 0.0001% by mass or less, and further preferably 0% by mass (i.e., free).

[0060] In one or more embodiments, the etching solution composition of the present invention may contain hydrogen peroxide or may not contain hydrogen peroxide.

[0061] In one or more embodiments, the etching solution composition of the present invention preferably does not generate turbidity at a temperature of 10° C. or higher, more preferably 5° C. or higher, further preferably 1° C. or higher, further preferably 0.5° C. or higher, further preferably 0° C. or higher. Whether turbidity is generated can be confirmed by the method described in the Examples.

[0062] [Method for producing etching liquid composition]

[0063] In one embodiment, the etching solution composition of the present invention can be obtained by mixing nitric acid, a polyamine having a number average molecular weight of 300 or more, a nitrogen-containing basic compound having a molecular weight of less than 300, water, and the above-mentioned optional components as required by a known method. Therefore, the present invention relates in one embodiment to a method for producing an etching solution composition (hereinafter also referred to as "the etching solution production method of the present invention"), which includes at least a step of mixing nitric acid, a polyamine having a number average molecular weight of 300 or more, a nitrogen-containing basic compound having a molecular weight of less than 300, and water.

[0064] In one or more embodiments, the term "at least nitric acid, a polyamine having a number average molecular weight of 300 or more, a nitrogen-containing alkaline compound having a molecular weight of less than 300, and water" in the present invention includes the case where nitric acid, a polyamine having a number average molecular weight of 300 or more, a nitrogen-containing alkaline compound having a molecular weight of less than 300, water, and the above optional components are mixed simultaneously or sequentially. The mixing order may not be particularly limited. The above-mentioned mixing can be carried out using, for example, a propeller-type stirrer, a liquid circulation stirring using a pump, a homogenizer, a homogenizer, an ultrasonic disperser, and a wet ball mill.

[0065] In the method for producing an etching solution of the present invention, the preferred blending amount of each component can be the same as the preferred blending amount of each component in the etching solution composition of the present invention described above.

[0066] In one or more embodiments, the "amount of each component in the etching solution composition" in the present invention refers to the amount of each component in the etching solution composition used in the etching step, that is, at the time of starting the etching process (at the time of use).

[0067] In one or more embodiments, the amount of each component in the etching solution composition of the present invention may be regarded as the content of each component in the etching solution composition of the present invention. However, due to the influence of neutralization, the amount of each component may be different from the content.

[0068] The embodiment of the etching liquid composition of the present invention may be a so-called one-liquid type supplied to the market in a state where all components are pre-mixed, or a so-called two-liquid type mixed when used. As an embodiment of the two-liquid etching liquid composition, there can be cited a two-liquid etching liquid composition composed of a solution containing nitric acid (the first liquid), and a solution containing a polyamine with a number average molecular weight of 300 or more and a nitrogen-containing alkaline compound with a molecular weight of less than 300 (the second liquid), in which the first liquid and the second liquid are mixed when used. After the first liquid and the second liquid are mixed, they can be diluted with water or an acid aqueous solution as needed. The first liquid or the second liquid may contain all or part of the water used to prepare the etching solution. The first liquid and the second liquid may each contain the above-mentioned optional components as needed.

[0069] From the viewpoint of uniformly etching the etched layer, the pH of the etching solution composition of the present invention is preferably 1 or less, more preferably 0 or less, further preferably less than 0, and further preferably about -1. It should be noted that the pH of the etching solution composition of the present invention may be preferably -5 or more, more preferably -3 or more. In the present invention, the pH of the etching solution composition is a value at 25°C, which can be measured using a pH meter, and specifically, can be measured using the method described in the Examples.

[0070] The etching liquid composition of the present invention can be stored and supplied in a concentrated state within a range that does not impair its stability. In this case, the manufacturing and transportation costs can be reduced, so it is preferred. In addition, the concentrated solution can be appropriately diluted with water or an acid aqueous solution as needed and used in the etching process. The dilution ratio can be set to 5 to 100 times, for example.

[0071] [Set]

[0072] In another aspect, the present invention relates to a kit for producing the etching solution composition of the present invention (hereinafter also referred to as “the kit of the present invention”).

[0073] As the kit of the present invention, for example, there can be mentioned the following kit (two-liquid etching solution), which contains a solution containing nitric acid (first liquid) and a solution containing a polyamine with a number average molecular weight of 300 or more and a nitrogen-containing basic compound with a molecular weight of less than 300 (second liquid) in a state where they are not mixed with each other, and they are mixed when used. After the first liquid and the second liquid are mixed, they can be diluted with water or an acid aqueous solution as needed. The first liquid or the second liquid can contain all or part of the water used to prepare the etching solution. The first liquid and the second liquid can each contain the above-mentioned optional components as needed. According to the kit of the present invention, an etching solution with excellent storage stability can be prepared.

[0074] [Etched layer]

[0075] In one or more embodiments, the etched layer to be etched using the etching liquid composition of the present invention is an etched layer containing at least one metal. Here, as a metal, there is no particular limitation as long as the effect of the present invention can be exerted, and for example, at least one metal selected from tungsten, tantalum, zirconium, hafnium, molybdenum, niobium, ruthenium, osmium, rhenium, rhodium, copper, nickel, cobalt, titanium, titanium nitride, aluminum oxide, aluminum, and iridium can be cited. Among them, the etching liquid composition of the present invention is preferably used for etching an etched layer containing at least one metal selected from the group of tungsten, molybdenum, niobium, tantalum, and zirconium in one or more embodiments, and is suitable for etching a tungsten film or a molybdenum film in one or more embodiments. That is, in one or more embodiments, as the etched layer, a tungsten film or a molybdenum film can be cited.

[0076] [Etching method]

[0077] The present invention relates in one embodiment to an etching method (hereinafter also referred to as "the etching method of the present invention"), which includes a step of etching a layer to be etched containing at least one metal using the etching solution composition of the present invention (hereinafter also referred to as "the etching step of the present invention"). By using the etching method of the present invention, in one or more embodiments, by using an etching solution with excellent storage stability, the productivity of the semiconductor substrate can be improved.

[0078] In the etching step of the present invention, examples of the etching treatment method include immersion etching and single-wafer etching.

[0079] In one or more embodiments, when the etched layer is a tungsten film, the temperature of the etching solution composition in the etching process of the present invention (etching temperature) is preferably 0°C or more, more preferably 50°C or more, and further preferably 70°C or more, and preferably 150°C or less, more preferably 130°C or less, and further preferably 110°C or less, from the viewpoint of reducing etching unevenness. More specifically, in one or more embodiments, when the etched layer is a tungsten film, the etching temperature is preferably 0°C or more and 150°C or less, more preferably 50°C or more and 130°C or less, and further preferably 70°C or more and 110°C or less.

[0080] In one or more embodiments, when the etched layer is a molybdenum film, the temperature of the etching solution composition in the etching process of the present invention (etching temperature) is preferably 0°C or more, more preferably 15°C or more, and more preferably 20°C or more, and preferably 80°C or less, more preferably 65°C or less, and more preferably 50°C or less, from the viewpoint of reducing etching unevenness. More specifically, in one or more embodiments, when the etched layer is a molybdenum film, the etching temperature is preferably 0°C or more and 80°C or less, more preferably 15°C or more and 65°C or less, and more preferably 20°C or more and 50°C or less.

[0081] In one or more embodiments, when the etched layer is a nickel film, the temperature of the etching solution composition in the etching process of the present invention (etching temperature) is preferably 0°C or more, more preferably 15°C or more, and further preferably 30°C or more, and preferably 80°C or less, more preferably 65°C or less, and further preferably 50°C or less, from the viewpoint of reducing etching unevenness. More specifically, in one or more embodiments, when the etched layer is a nickel film, the etching temperature is preferably 0°C or more and 80°C or less, more preferably 15°C or more and 65°C or less, and further preferably 30°C or more and 50°C or less.

[0082] In one or more embodiments, when the etched layer is a cobalt film, the temperature of the etching solution composition in the etching process of the present invention (etching temperature) is preferably 0° C. or higher, more preferably 15° C. or higher, and further preferably 30° C. or higher, from the viewpoint of reducing etching unevenness, and preferably 80° C. or lower, more preferably 65° C. or lower, and further preferably 50° C. or lower. More specifically, in one or more embodiments, when the etched layer is a cobalt 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 further preferably 30° C. or higher and 50° C. or lower.

[0083] In one or more embodiments, when the etched layer is a titanium film, the temperature of the etching solution composition in the etching process of the present invention (etching temperature) is preferably 0°C or more, more preferably 50°C or more, and further preferably 70°C or more, and preferably 150°C or less, more preferably 130°C or less, and further preferably 110°C or less, from the viewpoint of reducing etching unevenness. More specifically, in one or more embodiments, when the etched layer is a titanium film, the etching temperature is preferably 0°C or more and 150°C or less, more preferably 50°C or more and 130°C or less, and further preferably 70°C or more and 110°C or less.

[0084] In one or more embodiments, when the etched layer is a copper film, the temperature of the etching solution composition in the etching process of the present invention (etching temperature) is preferably 0° C. or higher, more preferably 15° C. or higher, and further preferably 30° C. or higher, and preferably 80° C. or lower, more preferably 65° C. or lower, and further preferably 50° C. or lower, from the viewpoint of reducing etching unevenness. More specifically, in one or more embodiments, when the etched layer is a copper 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 further preferably 30° C. or higher and 50° C. or lower.

[0085] In the etching step of the present invention, the etching time can be set to, for example, 1 minute or more and 180 minutes or less.

[0086] In one or more embodiments, the etching method of the present invention may include a step of preserving, storing or transporting the etching solution composition of the present invention at a temperature of 10° C. or less.

[0087] In one or more embodiments, the etching solution composition of the present invention and the etching method of the present invention can be used to etch metal in the manufacturing process of electronic devices, especially semiconductor wafers.

[0088] In one or more embodiments, the etching solution composition and the etching method of the present invention can be suitably used in the production of semiconductor wafers, thereby improving etching unevenness and improving productivity and yield.

[0089] In one or more embodiments, the etching solution composition and the etching method of the present invention can be used to etch electrodes in the manufacturing process of electronic devices, especially semiconductor memories such as non-volatile memories including NAND flash memories.

[0090] In one or more embodiments, the etching solution composition and the etching method of the present invention can be applied to the production of a pattern having a three-dimensional structure, thereby obtaining advanced devices such as a memory with a large capacity.

[0091] The etching liquid composition of the present invention and the etching method of the present invention can be used for the etching method disclosed in, for example, Japanese Patent Application Laid-Open No. 2020-145412.

[0092] Example

[0093] Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited to these examples at all.

[0094] 1. Preparation of etching solution (Examples 1 to 6, Comparative Example 1)

[0095] Nitric acid shown in Table 1, acids other than nitric acid (phosphoric acid, acetic acid), polyamines, nitrogen-containing basic compounds, and water were mixed to obtain etching solutions (pH: -1) of Examples 1 to 6 and Comparative Example 1.

[0096] The blending amount (mass %, active ingredient) of each component in the prepared etching solution is shown in Table 1. The blending amount of water in Table 1 also includes the blending amount of water contained in an acid aqueous solution or the like.

[0097] The following components were used to prepare the etching solution.

[0098] Nitric acid [Fujifilm Wako Pure Chemical Industries, Ltd., concentration 70%]

[0099] Phosphoric acid [manufactured by Phosphorus Chemical Industry Co., Ltd., concentration 85%]

[0100] Acetic acid [Fujifilm Wako Pure Chemical Industries, Ltd., 100% concentration]

[0101] PEI (polyethyleneimine) [number average molecular weight 1800, "EPOMIN SP-018" manufactured by Nippon Shokubai Co., Ltd.]

[0102] Ethylenediamine [molecular weight 60.1, Fujifilm Wako Pure Chemical Industries, Ltd.]

[0103] NH3 (ammonia) [molecular weight 17.03, manufactured by Kishida Chemical Co., Ltd., concentration 28%]

[0104] Triethylenetetramine [molecular weight 146.23, Fujifilm Wako Pure Chemical Industries, Ltd.]

[0105] Water [Ultrapure water produced using a continuous pure water production device (PURECONTI PC-2000VRL model) and a subsystem (MAKUACE KC-05H model) manufactured by Kurita Industry Co., Ltd.]

[0106] 2. Determination methods of various parameters

[0107] [pH of etching solution]

[0108] The pH of the etching solution at 25° C. is a value measured using a pH meter (manufactured by TOA-DKK Co., Ltd.), and is a value obtained by immersing the electrode of the pH meter in the etching solution for 1 minute.

[0109] 3. Evaluation of etching solution

[0110] [Whether turbidity occurs (storage stability)]

[0111] 20 ml of the etching solution composition just prepared was collected into a sample bottle, and whether turbidity was generated after being left at 1°C for different periods of time was visually confirmed. The one that did not generate turbidity even after being left at 48 hours or more was marked as A, the one that generated turbidity after more than 24 hours and less than 48 hours was marked as B, and the one that generated turbidity after less than 24 hours was marked as C. The results are shown in Table 1.

[0112] [Evaluation of Etching Unevenness of Molybdenum Plate]

[0113] After the etching solutions prepared with various compositions (Examples 1 to 6 and Comparative Example 1) were stored at 1°C for 1 week, a molybdenum plate with a length of 2 cm, a width of 2 cm, and a thickness of 0.1 mm, whose weight was previously measured, was immersed in these etching solutions, and the molybdenum plate was etched at 40°C for 30 minutes. Thereafter, after washing with water, the surface of the molybdenum plate was observed again using a shape measurement laser microscope VK-9710 (lens magnification 150 times) manufactured by KEYENCE to obtain a photograph, which was analyzed in the surface roughness mode of the device. In addition, the surface accuracy as an indicator of uneven etching was calculated by the following formula. The results are shown in Table 1. The smaller the value of the surface accuracy, the more it can be judged that the uneven etching is suppressed.

[0114] Surface accuracy (%) = surface roughness after etching / surface roughness before etching × 100

[0115] [Table 1]

[0116]

[0117] As shown in Table 1, compared with Comparative Example 1 which does not contain a nitrogen-containing basic compound having a molecular weight of less than 300, it is found that the etching solution compositions of Examples 1 to 6 are superior in storage stability because the generation of turbidity is suppressed even when stored at low temperatures.

[0118] In addition, in Examples 1 to 6, (a-c) 4 The relationship of / b shows that it is 0.01 or more and 600 or less, and it is found that the etching unevenness is suppressed more favorably.

[0119] Industrial Applicability

[0120] The etching solution composition of the present invention has excellent storage stability and can be used in a method for producing a large-capacity semiconductor memory.

Claims

1. An etching liquid composition for etching an etched layer comprising at least one metal, The etching solution composition comprises nitric acid, a polyamine with a number average molecular weight of 300 or more, a nitrogen-containing basic compound with a molecular weight of less than 300, and water.

2. The etching solution composition according to claim 1, wherein The blending amount a of nitric acid in mass %, the blending amount b of the polyamine having a number average molecular weight of 300 or more, and the blending amount c of the nitrogen-containing basic compound having a molecular weight of less than 300 in mass % satisfy the relationship (a-c): 4 / b≤600. 3 . The etching solution composition according to claim 1 , further comprising an acid other than nitric acid.

4. The etching solution composition according to claim 3, wherein The acid other than nitric acid is at least one selected from the group consisting of phosphoric acid, acetic acid, methoxyacetic acid, and ethoxyacetic acid.

5. The etching solution composition according to any one of claims 1 to 4, wherein The metal is at least one metal selected from tungsten, tantalum, zirconium, hafnium, molybdenum, niobium, ruthenium, osmium, rhenium, rhodium, copper, nickel, cobalt, titanium, titanium nitride, aluminum oxide, aluminum, and iridium. 6 . An etching method comprising the step of etching a layer to be etched containing at least one metal using the etching solution composition according to claim 1 .

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