JP2024002670A - Etchant composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an etchant composition with excellent storage stability.

SOLUTION: The etchant composition is for etching a layer to be etched containing at least one metal. The etchant composition includes nitric acid, a polyvalent amine having a number average molecular weight of 300 or more, and water. The blending amount of water is equal to or less than 30 mass%. The blending amount of nitric acid (mass%) a and the blending amount of polyvalent amine (mass%) b having an average molecular weight of 300 or more satisfy the relationship a⁴/b≤600.

SELECTED DRAWING: None

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present disclosure relates to an etching liquid composition and an etching method using the same.

In the manufacturing process of semiconductor devices, at least one of tungsten, tantalum, zirconium, hafnium, molybdenum, niobium, ruthenium, osmium, rhenium, rhodium, copper, nickel, cobalt, titanium, titanium nitride, alumina, aluminum, iridium, etc. A process of etching a layer to be etched containing metal into a predetermined pattern shape is performed.
In recent years, the semiconductor field has become more highly integrated, requiring more complex and finer wiring, and demands for pattern processing technology and etching solutions are also increasing, and various etching methods and solutions are being proposed. (Patent Documents 1 to 4).

For example, in Patent Document 1, an etching solution composition containing 50 to 80% by mass of phosphoric acid, 0.5 to 10% by mass of nitric acid, 5 to 30% by mass of acetic acid, and 0.01 to 5% by mass of imidazole. A method has been proposed in which a multilayer film such as a Cu/Mo laminated metal film is etched all at once using a material.
In Patent Document 2, a titanium-containing layer and a silicon-containing layer are etched 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 having nitrogen atoms. A method of etching has been proposed.
In Patent Document 3, phosphoric acid, nitric acid, and a polyalkylene polyamine containing three or more amino groups in one molecule are used for etching a metal film having at least one layer of a metal thin film of molybdenum or a molybdenum alloy. Etching solutions have been proposed.
US Pat. No. 5,001,201 discloses an etching solution suitable for both tungsten-containing metals and TiN-containing materials selected from water, oxidizing agents, fluorine-containing etching compounds, organic solvents, chelating agents, corrosion inhibitors, and surfactants. Etching solutions containing at least one or more components have been proposed.

Japanese Patent Application Publication No. 2012-49535 Japanese Patent Application Publication No. 2015-144230 JP2013-237873A JP2022-42324A

As the etching solution, a mixed acid aqueous solution (strongly acidic aqueous solution) containing phosphoric acid, nitric acid, and acetic acid is generally used. Patent Document 2 proposes adding a nitrogen-containing organic compound such as polyethyleneimine as an agent to suppress etching and improve etching selectivity, but adding polyethyleneimine or the like to the mixed acid aqueous solution causes turbidity. The storage stability of the etching solution deteriorates. In particular, there is a problem that turbidity tends to occur when stored at low temperatures (for example, 10° C. or lower).

Therefore, in one aspect, the present disclosure provides an etching solution composition with excellent storage stability and an etching method using the same.

In one aspect, the present disclosure provides an etchant composition for etching a layer to be etched containing at least one metal, the etchant composition comprising nitric acid and a polyester having a number average molecular weight of 300 or more. amine and water, the amount of water is 30% by mass or less, the amount of nitric acid (% by mass) a, and the amount of polyvalent amine having a number average molecular weight of 300 or more (% by mass). ) b satisfies the relationship of a ⁴ /b≦600. Note that a and b each represent mass or mass % (the same applies hereinafter).

In one embodiment, the present disclosure relates to an etching method that includes a step of etching a layer to be etched containing at least one metal using the etching solution composition of the present disclosure.

According to the present disclosure, in one embodiment, it is possible to provide an etching liquid composition with excellent storage stability.

As a result of intensive studies by the present inventors, the use of an etching solution containing nitric acid and a polyvalent amine with a number average molecular weight of 300 or more in a predetermined ratio improves storage stability, especially at low temperatures (below 10°C). ) was found to be able to improve storage stability.

In one aspect, the present disclosure provides an etchant composition for etching a layer to be etched containing at least one metal, the etchant composition comprising nitric acid and a polyester having a number average molecular weight of 300 or more. amine and water, the amount of water is 30% by mass or less, the amount of nitric acid (% by mass) a, and the amount of polyvalent amine having a number average molecular weight of 300 or more (% by mass). ) b satisfies the relationship of a ⁴ /b≦600 (hereinafter also referred to as "the etching solution composition of the present disclosure").

Although the details of the mechanism by which the effects of the present disclosure are expressed are not clear, it is inferred as follows.
Polyvalent amines have multiple amino groups in their molecules, and all of these amino groups can form salts with nitric acid in water. How many amino groups in the polyvalent amine molecule form a salt with nitric acid depends on the amount of nitrate ions and ammonium ions contained in the etching solution composition. As the amount of polyvalent amine increases, the amount of nitrate ions decreases relative to the amount of ammonium ions, and therefore the amount of amino groups that form a salt with nitric acid in one molecule of the polyvalent amine decreases. When the blending amount of nitric acid increases, in addition to the increase in the amount of nitric acid, the pH greatly decreases, so the amount of nitric acid ions in the etching solution composition increases dramatically, forming a salt with nitric acid in one molecule of polyvalent amine. The amount of amino groups increases significantly. Also, amines/nitrates are not very soluble in water, so when the concentration of water is low, the more amino groups forming a salt with nitric acid, the lower the solubility in the solution, especially at low temperatures. (for example, below 10°C), the liquid tends to become cloudy. As mentioned above, the amount of salt formed depends on the amount of nitrate ions and ammonium ions, and is greatly influenced by the amount of nitric acid. The present inventors confirmed in detail the influence of the ratio between the amount of nitric acid ions and the amount of ammonium ions, and found that the amount of nitric acid (mass%) a and the amount of polyvalent amine with a number average molecular weight of 300 or more ( It has been revealed that when b satisfies the relationship a ⁴ /b≦600 (mass%), the liquid is less likely to become cloudy even when stored at low temperatures (for example, 10° C. or lower), and storage stability can be improved.
Further, since the etching liquid composition of the present disclosure has a stable composition, it is thought that uniform contact with the layer to be etched is made and uniform etching can be performed.
However, the present disclosure does not need to be interpreted as being limited to these mechanisms.

[nitric acid]
The content of nitric acid in the etching solution composition of the present disclosure is preferably 0.5% by mass or more, more preferably 1% by mass or more, even more preferably 1.5% by mass or more, from the viewpoint of improving the etching rate. From the viewpoint of improving storage stability, the content is preferably 20% by mass or less, more preferably 10% by mass or less, and even more preferably 5% by mass or less. More specifically, the amount of nitric acid in the etching solution composition of the present disclosure is preferably 0.5% by mass or more and 20% by mass or less, more preferably 1% by mass or more and 10% by mass or less, and 1.5% by mass or less. % or more and 5% by mass or less is more preferable.

[Polyvalent amine]
In one or more embodiments, the polyvalent amine contained in the etching solution composition of the present disclosure may be a compound having two or more amino groups in the molecule. In one or more embodiments, polyvalent amines include polyalkylene imines, polyalkylene polyamines, alkanolamines, alicyclic amines, and compounds having an amino group and an ethylenically unsaturated double bond, from the viewpoint of etching suppression. Examples include polymers having structural units derived from the above, aromatic amines, and the like. Examples of the polyalkyleneimine include polyethyleneimine (PEI), and branched polyethyleneimine is preferred. Examples of polyalkylene polyamines include diethylenetriamine, pentaethylenehexamine, and the like. Examples of alkanolamines include 2-(2-aminoethylamino)ethanol. Examples of the alicyclic amine include N-(2-hydroxyethyl)piperazine and N-(2-aminoethyl)piperazine. Examples of polymers having constitutional units derived from compounds having an amino group and an ethylenically unsaturated double bond include diallylamine copolymers, diallylamine/sulfur dioxide copolymers, diallyldimethylammonium chloride polymers, diallyldimethylammonium chloride/ Examples include sulfur dioxide copolymers. Examples of aromatic amines include benzotriazole, aminopyrazole, aminopyridine, aminopyrimidine, aminopyrazine, aminooxazole, and thiazoleamine.
Among these, polyalkylene imine such as PEI is preferred from the viewpoint of suppressing etching.
One type of polyvalent amine may be used alone, or two or more types may be used in combination.

In one or more embodiments, the number average molecular weight of the polyvalent amine is 300 or more, preferably 600 or more, more preferably 1,200 or more, and from the viewpoint of improving storage stability, in one or more embodiments. , preferably 100,000 or less, more preferably 5,000 or less, and even more preferably 3,000 or less. More specifically, the number average molecular weight of the polyvalent amine 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.

In the present disclosure, the number average molecular weight can be measured by gel permeation chromatography (GPC) under the following conditions.
<GPC conditions>
Sample solution: adjusted to a concentration of 0.1 wt% Device/detector: HLC-8320GPC (integrated GPC) manufactured by Tosoh Corporation Column: α-M + α-M (manufactured by Tosoh Corporation)
Eluent: 0.15 mol/L Na ₂ SO ₄ , 1% CH ₃ COOH/water Column temperature: 40°C
Flow rate: 1.0mL/min
Sample liquid injection amount: 100μL
Standard polymer: pullulan with known molecular weight (Shodex P-5, P-50, P-200, P-800)

From the viewpoint of improving storage stability, the blending amount of the polyvalent amine in the etching solution composition of the present disclosure is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, and 0.4% by mass or more. is more preferable, and from the viewpoint of liquid permeability during filtration depending on solution viscosity, it is preferably 20% by mass or less, more preferably 10% by mass or less, and even more preferably 5% by mass or less. More specifically, the blending amount of the polyvalent amine in the etching solution composition of the present disclosure 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, More preferably 0.4% by mass or more and 5% by mass or less. When the polyvalent amine is a combination of two or more types, the blending amount of the polyvalent amine is the total blending amount of the polyvalent amine.

In the present disclosure, when the blending amount (mass%) of nitric acid is a, and the blending amount (mass%) of a polyvalent amine having a number average molecular weight of 300 or more is b, the blending amount a of nitric acid and the number average molecular weight 300 The above blending amount b of the polyvalent amine satisfies the relationship a ⁴ /b≦600. From the viewpoint of improving storage stability and improving storage stability at temperatures of 10° C. or lower, a ⁴ /b is 600 or less, preferably 550 or less, more preferably 500 or less, and even more preferably 450 or less. Preferably, from the viewpoint of uniform etching of the layer to be etched, it is preferably 0.01 or more, more preferably 0.1 or more, and even more preferably 0.5 or more.

[Acids other than nitric acid]
The etching liquid composition of the present disclosure can further contain an acid other than nitric acid from the viewpoint of uniformly etching the layer to be etched. Acids other than nitric acid may be used alone or in combination of two or more.
Examples of acids other than nitric acid include at least one selected from phosphoric acid, hydrochloric acid, sulfuric acid, and organic acids. Examples of organic acids include 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, and tri-acid. At least one selected from mellitic acid, hydroxyacetic acid, lactic acid, salicylic acid, malic acid, tartaric acid, citric acid, aspartic acid, and glutamic acid is mentioned. Among these, as the acid other than nitric acid, at least one selected from phosphoric acid, acetic acid, methoxyacetic acid, and ethoxyacetic acid is preferable from the viewpoint of uniformly etching the layer to be etched, and at least one of phosphoric acid and acetic acid is more preferable. Preferably, a combination of phosphoric acid and acetic acid is more preferable.

When the etching solution of the present disclosure further contains an acid other than nitric acid, the amount of the acid other than nitric acid in the etching solution of the present disclosure is preferably 65% by mass or more, and 70% by mass or more from the viewpoint of uniform etching of the layer to be etched. It is more preferably at least 75% by mass, even more preferably at least 75% by mass, and from the same point of view, it is preferably at most 98% by mass, more preferably at most 95% by mass, and even more preferably at most 90% by mass. More specifically, the amount of acids other than nitric acid in the etching solution composition of the present disclosure 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 75% by mass. The content is more preferably 90% by mass or less. When the types of acids other than nitric acid are a combination of two or more, the amount of the acids other than nitric acid is the total amount of the acids other than nitric acid.
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 disclosure is 50% by mass or more and 95% by mass or less from the viewpoint of uniform etching of the layer to be etched. is preferable, 55% by mass or more and 93% by mass or less is more preferable, and even more preferably 60% by mass or more and 90% by mass or less. From the same viewpoint, the amount of acetic acid in the etching solution composition of the present disclosure 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 5% by mass or more and 30% by mass. The following are more preferable.

[water]
The etching liquid composition of the present disclosure contains water in one or more embodiments. Examples of the water contained in the etching solution of the present disclosure include distilled water, ion exchange water, pure water, ultrapure water, and the like.

The content of water in the etching solution composition of the present disclosure is preferably 2% by mass or more, more preferably 5% by mass or more, even more preferably 7% by mass or more, from the viewpoint of improving storage stability, and From the viewpoint of uniform etching of the layer, the content is preferably 30% by mass or less, more preferably 25% by mass or less, and even more preferably 20% by mass or less. More specifically, the amount of water in the etching solution composition of the present disclosure 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 7% by mass or more and 20% by mass. % or less is more preferable.

[Other ingredients]
The etching solution composition of the present disclosure may further contain other components as long as the effects of the present disclosure are not impaired. Other components include chelating agents, surfactants, solubilizers, preservatives, rust preventives, bactericidal agents, antibacterial agents, antioxidants, and the like.

In one or more embodiments, the etching solution composition of the present disclosure can be substantially free of imidazole. The amount of imidazole in the etching solution composition of the present disclosure is preferably less than 0.01% by mass, more preferably 0.001% by mass or less, and even more preferably 0% by mass.

In one or more embodiments, the etching solution composition of the present disclosure can be substantially free of fluorine-containing compounds. The amount of the fluorine-containing compound in the etching solution composition of the present disclosure is preferably less than 0.001% by mass, more preferably 0.0001% by mass or less, and even more preferably 0% by mass.

In one or more embodiments, the etching solution composition of the present disclosure may contain hydrogen peroxide or may not contain hydrogen peroxide.

In one or more embodiments, the etching solution composition of the present disclosure is preferably 10°C or higher, more preferably 5°C or higher, even more preferably 1°C or higher, even more preferably 0.5°C or higher, and still more preferably 0°C or higher. No turbidity occurs at temperatures above ℃. The presence or absence of turbidity can be confirmed by the method described in Examples.

[Method for manufacturing etching liquid composition]
In one embodiment, the etching solution composition of the present disclosure is obtained by blending nitric acid, a polyvalent amine having a number average molecular weight of 300 or more, water, and optionally the above-mentioned optional components by a known method. . Therefore, in one aspect, the present disclosure provides a method for producing an etching liquid composition (hereinafter referred to as "the present disclosure (also referred to as "method for producing an etching solution").
In the present disclosure, "blending at least nitric acid, a polyvalent amine with a number average molecular weight of 300 or more, and water" means, in one or more embodiments, nitric acid and a polyvalent amine with a number average molecular weight of 300 or more. The method includes mixing the polyvalent amine, water, and optionally the above-mentioned optional components simultaneously or sequentially. The order of mixing may not be particularly limited. The blending can be carried out using a mixer such as a propeller type stirrer, liquid circulation stirring using a pump, a homomixer, a homogenizer, an ultrasonic disperser, and a wet ball mill.
In the etching solution manufacturing method of the present disclosure, 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 disclosure described above.

In the present disclosure, "the amount of each component in the etching solution composition" refers to the amount used in the etching process, that is, at the time of starting use for the etching process (at the time of use), in one or more embodiments. The amount of each component in the etching solution composition.
The blending amount of each component in the etching solution composition of the present disclosure can be considered as the content of each component in the etching solution composition of the present disclosure in one or more embodiments. However, if it is affected by neutralization, the blending amount and content may differ.

Embodiments of the etching solution composition of the present disclosure may be a so-called one-component type, in which all components are supplied to the market in a pre-mixed state, or a so-called two-component type, in which all components are mixed at the time of use. There may be. One embodiment of a two-component etching solution composition includes a solution containing nitric acid (first solution) and a solution containing a polyvalent amine having a number average molecular weight of 300 or more (second solution), Examples include those in which the first liquid and the second liquid are mixed during use. After the first liquid and the second liquid are mixed, they may be diluted with water or an acid aqueous solution as necessary. The first liquid or the second liquid may contain all or part of the water used for preparing the etching liquid. The first liquid and the second liquid may each contain the above-mentioned optional components as necessary.

The pH of the etching solution composition of the present disclosure is preferably 1 or less, more preferably 0 or less, even more preferably less than 0, and even more preferably about -1 from the viewpoint of uniform etching of the layer to be etched. Note that the pH of the etching solution composition of the present disclosure can be preferably -5 or higher, more preferably -3 or higher. In the present disclosure, the pH of the etching solution composition is a value at 25° C., and can be measured using a pH meter, specifically, by the method described in Examples.

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

[kit]
In other aspects, the present disclosure relates to a kit for producing the etching solution composition of the present disclosure (hereinafter also referred to as "kit of the present disclosure").
The kit of the present disclosure includes, for example, a solution containing nitric acid (first solution) and a solution containing a polyvalent amine having a number average molecular weight of 300 or more (second solution) in an unmixed state; An example is a kit (two-component etching solution) in which the etching solution is mixed at the time of use. After the first liquid and the second liquid are mixed, they may be diluted with water or an acid aqueous solution as necessary. The first liquid or the second liquid may contain all or part of the water used for preparing the etching liquid. The first liquid and the second liquid may each contain the above-mentioned optional components as necessary. According to the kit of the present disclosure, an etching solution with excellent storage stability can be prepared.

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

[Etching method]
In one aspect, the present disclosure provides an etching process that includes a step of etching a layer to be etched containing at least one metal (hereinafter also referred to as "the etching step of the present disclosure") using the etching solution composition of the present disclosure. method (hereinafter also referred to as "the etching method of the present disclosure"). By using the etching method of the present disclosure, in one or more embodiments, productivity of semiconductor substrates can be improved by using an etching solution with excellent storage stability.

In the etching process of the present disclosure, examples of the etching treatment method include immersion etching, single wafer etching, and the like.

In one or more embodiments, when the layer to be etched is a tungsten film, the temperature of the etching solution composition (etching temperature) in the etching process of the present disclosure is preferably 0° C. or higher, and 50° C. from the viewpoint of reducing etching unevenness. The above temperature is more preferable, 70°C or higher is even more preferable, 150°C or lower is preferable, 130°C or lower is more preferable, and even more preferably 110°C or lower. More specifically, in one or more embodiments, when the layer to be etched is a tungsten film, the etching temperature is preferably 0°C or more and 150°C or less, more preferably 50°C or more and 130°C or less, and 70°C or more and 110°C or less. C. or less is more preferable.
In one or more embodiments, when the layer to be etched is a molybdenum film, the temperature of the etching solution composition (etching temperature) in the etching process of the present disclosure is preferably 0°C or higher, and 15°C or higher from the viewpoint of reducing etching unevenness. The above temperature is more preferable, 20°C or higher is even more preferable, 80°C or lower is preferable, 65°C or lower is more preferable, and even more preferably 50°C or lower. More specifically, in one or more embodiments, when the layer to be etched is a molybdenum film, the etching temperature is preferably 0°C or more and 80°C or less, more preferably 15°C or more and 65°C or less, and 20°C or more and 50°C or less. C. or less is more preferable.
In one or more embodiments, when the layer to be etched is a nickel film, the temperature of the etching solution composition (etching temperature) in the etching process of the present disclosure is preferably 0° C. or higher, and 15° C. from the viewpoint of reducing etching unevenness. The temperature is more preferably 30°C or higher, further preferably 80°C or lower, more preferably 65°C or lower, and even more preferably 50°C or lower. More specifically, in one or more embodiments, when the layer to be etched is a 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 30°C or more and 50°C or less. C. or less is more preferable.
In one or more embodiments, when the layer to be etched is a cobalt film, the temperature of the etching solution composition (etching temperature) in the etching process of the present disclosure is preferably 0° C. or higher, and 15° C. from the viewpoint of reducing etching unevenness. The temperature is more preferably 30°C or higher, further preferably 80°C or lower, more preferably 65°C or lower, and even more preferably 50°C or lower. More specifically, in one or more embodiments, when the layer to be etched is a cobalt 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 30°C or more and 50°C or less. C. or less is more preferable.
In one or more embodiments, when the layer to be etched is a titanium film, the temperature of the etching solution composition (etching temperature) in the etching process of the present disclosure is preferably 0°C or higher, and 50°C or higher from the viewpoint of reducing etching unevenness. The above temperature is more preferable, 70°C or higher is even more preferable, 150°C or lower is preferable, 130°C or lower is more preferable, and even more preferably 110°C or lower. More specifically, in one or more embodiments, when the layer to be etched 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 70°C or more and 110°C or less. C. or less is more preferable.
In one or more embodiments, when the layer to be etched is a copper film, the temperature of the etching solution composition (etching temperature) in the etching process of the present disclosure is preferably 0° C. or higher, and 15° C. from the viewpoint of reducing etching unevenness. The temperature is more preferably 30°C or higher, further preferably 80°C or lower, more preferably 65°C or lower, and even more preferably 50°C or lower. More specifically, in one or more embodiments, when the layer to be etched is a copper 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 30°C or more and 50°C or less. C. or less is more preferable.

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.

In one or more embodiments, the etching method of the present disclosure may include a step of preserving or storing or transporting the etching solution composition of the present disclosure at a temperature of 10° C. or lower.

The etchant composition of the present disclosure and the etching method of the present disclosure can be used in one or more embodiments to etch metal in the manufacturing process of electronic devices, particularly semiconductor wafers.
The etching liquid composition of the present disclosure and the etching method of the present disclosure can be suitably used for manufacturing semiconductor wafers in one or more embodiments. This improves etching unevenness and improves productivity and yield.
In one or more embodiments, the etching solution composition of the present disclosure and the etching method of the present disclosure are used to etch electrodes in the manufacturing process of electronic devices, particularly semiconductor memories such as nonvolatile memories including NAND flash memories. It can be used for
The etching solution composition of the present disclosure and the etching method of the present disclosure can be suitably used for producing a pattern having a three-dimensional structure in one or more embodiments. This makes it possible to obtain advanced devices such as large-capacity memories.
The etching solution composition of the present disclosure and the etching method of the present disclosure can be used, for example, in an etching method as disclosed in JP-A-2020-145412.

EXAMPLES The present disclosure will be specifically explained below with reference to Examples, but the present disclosure is not limited to these Examples in any way.

1. Preparation of etching solution (Examples 1 to 12, Comparative Examples 1 to 3)
Etching solutions (pH: -1) of Examples 1 to 12 and Comparative Examples 1 to 3 were obtained by blending nitric acid, acids other than nitric acid (phosphoric acid, acetic acid), polyvalent amines, and water shown in Table 1.
Table 1 shows the amount (% by mass, effective content) of each component in the prepared etching solution. Note that the amount of water contained in Table 1 also includes the amount of water contained in the acid aqueous solution and the like.

The following components were used to prepare the etching solution.
Nitric acid [Fujifilm Wako Pure Chemical Industries, Ltd., concentration 70%]
Phosphoric acid [manufactured by Rin Kagaku Kogyo Co., Ltd., concentration 85%]
Acetic acid [Fujifilm Wako Pure Chemical Industries, Ltd., concentration 100%]
Polyethyleneimine [number average molecular weight 1,800, “Epomin SP-018” manufactured by Nippon Shokubai Co., Ltd.]
Water [ultra pure water produced using Kurita Water Industries, Ltd.'s continuous pure water production equipment (Pure Conti PC-2000VRL model) and subsystem (MacAce KC-05H model)]

2. How to measure each parameter [pH of etching solution]
The pH value of the etching solution at 25° C. is a value measured using a pH meter (manufactured by DKK Toa), and is a value obtained 1 minute after immersing the electrode of the pH meter in the etching solution.

3. Evaluation of etching solution [Presence or absence of turbidity (storage stability)]
Immediately after preparation, 20 ml of the etching liquid composition was taken into a sample bottle, and the presence or absence of turbidity was visually confirmed when the sample bottle was allowed to stand at 1° C. for each hour. Those that did not become turbid even after being left for 48 hours or more were rated as ○, those that became turbid between 24 and 48 hours were rated △, and those that became turbid for less than 24 hours were rated as ×. The results are shown in Table 1.

As shown in Table 1, in all Examples 1 to 12, the blending amount (mass%) of nitric acid a and the blending amount (mass%) b of polyvalent amine satisfy ^{a 4} /b≦600. It was found that compared to Comparative Examples 1 to 3 where /b>600, the generation of turbidity was suppressed even when stored at low temperatures, and the storage stability was excellent.

The etching solution composition of the present disclosure has excellent storage stability and is useful in a method for manufacturing a large-capacity semiconductor memory.

Claims (5)

An etching liquid composition for etching a layer to be etched containing at least one metal, the composition comprising:
The etching solution composition contains nitric acid, a polyvalent amine having a number average molecular weight of 300 or more, and water,
The blending amount of water is 30% by mass or less,
An etching liquid composition in which the amount (mass%) a of nitric acid and the amount (mass %) b of a polyvalent amine having a number average molecular weight of 300 or more satisfy the relationship a ⁴ /b≦600. The etching liquid composition according to claim 1, further comprising an acid other than nitric acid. The etching liquid composition according to claim 2, wherein the acid other than nitric acid is at least one selected from phosphoric acid, acetic acid, methoxyacetic acid, and ethoxyacetic acid. 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, alumina, aluminum, and iridium. , the etching solution composition according to any one of claims 1 to 3. An etching method comprising the step of etching a layer to be etched containing at least one metal using the etching liquid composition according to any one of claims 1 to 4.