WO2024053623A1

WO2024053623A1 - Etchant composition

Info

Publication number: WO2024053623A1
Application number: PCT/JP2023/032305
Authority: WO
Inventors: 内田洋平
Original assignee: 花王株式会社
Priority date: 2022-09-06
Filing date: 2023-09-05
Publication date: 2024-03-14
Also published as: JP2024037160A

Abstract

Provided as one embodiment is an etchant composition having excellent storage stability.　An embodiment of the present disclosure relates to an etchant composition for etching layers containing at least one metal, the etchant composition comprising nitric acid, a polyvalent amine having a number-average molecular weight of 300 or higher, a nitrogen-containing basic compound having a molecular weight less than 300, and water.

Description

Etching liquid composition

The present disclosure relates to an etching solution 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. has been done.

For example, in JP2012-49535A (Patent Document 1), 50 to 80 mass% phosphoric acid, 0.5 to 10 mass% nitric acid, 5 to 30 mass% acetic acid, and 0.01 to 5 mass% A method has been proposed in which a multilayer film such as a Cu/Mo laminated metal film is etched at once using an etching solution composition containing % of imidazole.
In JP-A No. 2015-144230 (Patent Document 2), titanium is 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 a nitrogen atom. A method of etching a silicon-containing layer and a silicon-containing layer has been proposed.
JP-A No. 2013-237873 (Patent Document 3) discloses that phosphoric acid, nitric acid, three or more amino acids 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 containing polyalkylene polyamines containing groups have been proposed.
JP-A No. 2022-2324 (Patent Document 4) discloses an etching solution suitable for both tungsten-containing metals and TiN-containing materials, which contains water, an oxidizing agent, a fluorine-containing etching compound, an organic solvent, a chelating agent, and a corrosion inhibitor. Etching solutions containing at least one or two or more components selected from surfactants and surfactants have been proposed.

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. The present invention relates to an etching liquid composition containing a functional amine, a nitrogen-containing basic compound having a molecular weight of less than 300, and water.

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 liquid composition of the present disclosure.

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 liquid composition with excellent storage stability and an etching method using the same.

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, storage stability was improved by using an etching solution containing nitric acid, a polyvalent amine with a number average molecular weight of 300 or more, and a nitrogen-containing basic compound with a molecular weight of less than 300. It has been found that the storage stability can be particularly improved at low temperatures (10° C. or lower).

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. The present invention relates to an etching solution composition (hereinafter also referred to as "the etching solution composition of the present disclosure") containing a amine, a nitrogen-containing basic compound having a molecular weight of less than 300, and water.

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. Salts of amino groups and nitric acid do not have very high solubility in water, so the greater the number of amino groups forming a salt with nitric acid, the lower the solubility in the solution, especially at low temperatures (e.g. 10°C). (below), the liquid becomes more likely to become cloudy. In the present disclosure, a polyvalent amine having a number average molecular weight of 300 or more and a nitrogen-containing basic compound having a molecular weight of less than 300 are used together. As a result, the nitrogen-containing basic compound forms a salt with nitric acid, so the amount of nitric acid ions decreases, and the amount of amino groups that form a salt with nitric acid in one molecule of polyvalent amine decreases. It is thought that the amount of salt between the amino group and nitric acid in one molecule of polyvalent amine is reduced, and the solution is less likely to become cloudy even when stored at low temperatures (e.g., below 10°C), improving storage stability. .
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 8% 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 8% by mass or less is more preferable.

[Polyvalent amine with number average molecular weight of 300 or more]
In one or more embodiments, the polyvalent amine having a number average molecular weight of 300 or more 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, the polyvalent amine includes polyalkylene imine, a polymer having a structural unit derived from a compound having an amino group and an ethylenically unsaturated double bond, etc. from the viewpoint of etching suppression. . Examples of the polyalkyleneimine include polyethyleneimine (PEI), and branched polyethyleneimine is preferred. Examples of the polymer having a structural unit derived from a compound having an amino group and an ethylenically unsaturated double bond include diallylamine copolymer, diallylamine/sulfur dioxide copolymer, diallyldimethylammonium chloride polymer, and diallyldimethylammonium chloride. /sulfur dioxide copolymer. Among these, polyalkylene imines such as PEI are preferable as the polyvalent amine from the viewpoint of etching suppression. Polyvalent amines having a number average molecular weight of 300 or more may be used alone or in combination of two or more.

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, from the viewpoint of etching suppression, and from the viewpoint of improving storage stability. From this point of view, it is 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)

The amount of polyvalent amine having a number average molecular weight of 300 or more 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, from the viewpoint of improving storage stability. It is preferably 0.4% by mass or more, more preferably 0.4% by mass or more, and from the viewpoint of liquid permeability during filtration depending on the viscosity of the solution, 20% by mass or less is preferable, more preferably 10% by mass or less, and even more preferably 5% by mass or less. . More specifically, the amount of polyvalent amine having a number average molecular weight of 300 or more in the etching solution composition of the present disclosure is preferably 0.1% by mass or more and 20% by mass or less, and 0.2% by mass or more. It is more preferably 10% by mass or less, and even 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 thereof.

[Nitrogen-containing basic compound having a molecular weight of less than 300]
In one or more embodiments, the molecular weight of the nitrogen-containing basic compound contained in the etching solution composition of the present disclosure is less than 300, preferably 250 or less, more preferably 200 or less. Preferably, from the viewpoint of uniform etching of the layer to be etched, the number is preferably 15 or more, more preferably 20 or more, and even more preferably 30 or more. 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.

In one or more embodiments, the nitrogen-containing basic compound is at least one selected from ammonia, an alkylamine, an alkanolamine, an alicyclic amine, an aromatic amine, and a polyalkylene polyamine, from the viewpoint of improving storage stability. species are preferred, and at least one selected from ammonia, alicyclic amines, and polyalkylene polyamines is more preferred.
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 thiazoleamine. 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 alkylene diamines, dialkylene triamines and trialkylene tetramines. Examples of the alkylene diamine include ethylene diamine. Examples of the dialkylene triamine include diethylene triamine. Examples of the trialkylenetetramine include triethylenetetramine.
The nitrogen-containing basic compounds having a molecular weight of less than 300 may be used alone or in combination of two or more.

The amount of the nitrogen-containing basic compound having a molecular weight of less than 300 in the etching solution composition of the present disclosure is preferably 0.4% by mass or more, more preferably 0.8% by mass or more, from the viewpoint of improving storage stability. It is preferably 1.2% by mass or more, more preferably 1.2% by mass or more, and from the viewpoint of liquid permeability during filtration depending on the viscosity of the solution, 20% by mass or less is preferable, more preferably 15% by mass or less, and even more preferably 10% by mass or less. . 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 disclosure is preferably 0.4% by mass or more and 20% by mass or less, and 0.8% by mass or more. It is more preferably 15% by mass or less, and even more preferably 1.2% by mass or more and 10% by mass or less. When the nitrogen-containing basic compound is a combination of two or more types, the blending amount of the nitrogen-containing basic compound is the total blending amount of the nitrogen-containing basic compound.

In the present disclosure, the blending amount (mass %) a of nitric acid, the blending amount (mass %) b of a polyvalent amine having a number average molecular weight of 300 or more, and the blending amount (mass %) of a nitrogen-containing basic compound having a molecular weight of less than 300 %)c preferably satisfies the relationship (ac) ⁴ /b≦600. In one or more embodiments, a and c satisfy the relationship a<c, a=c, or a>c. Note that a, b, and c each represent mass or mass % (the same applies hereinafter).
(a-c) ⁴ /b is preferably 600 or less, more preferably 550 or less, even more preferably 500 or less, from the viewpoint of improving storage stability and improving storage stability at a temperature of 10 ° C. or less, 400 or less is more preferable, and from the viewpoint of uniform etching of the layer to be etched, 0.01 or more is preferable, 0.1 or more is more preferable, 0.5 or more, 50 or more, 100 or more, 200 or more, or 300 or more. The above is more preferable.
From the same viewpoint, (ac) ⁴ /b is preferably 0.01 or more and 600 or less, more preferably 0.1 or more and 600 or less, even more preferably 0.5 or more and 600 or less, and even more preferably 50 or more and 600 or less. It is preferably 100 or more and 600 or less, still more preferably 200 or more and 600 or less, even more preferably 300 or more and 600 or less, even more preferably 300 or more and 550 or less, and even more preferably 300 or more and 500 or less.

Here, the reason why (ac) ⁴ /b is preferably 600 or less will be explained below.
As mentioned above, the polyvalent amine has a plurality of amino groups in its molecule, and all of these amino groups can form a salt 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. When a polyvalent amine with a number average molecular weight of 300 or more and a nitrogen-containing basic compound with a molecular weight of less than 300 coexist, the nitrogen-containing basic compound forms a salt with nitric acid, so the amount of nitrate ions decreases, and the polyvalent amine It is thought that the amount of amino groups that form salts with nitric acid in one amine molecule is reduced. 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 the amount of ammonium ions, and this is greatly influenced by the amount of nitric acid and the amount of the nitrogen-containing basic compound.
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 ( When the amount (mass %) b of the nitrogen-containing basic compound having a molecular weight of less than 300 satisfies the relationship (a-c) ⁴ /b≦600, low temperature (for example, 10°C It was revealed that even when stored in the following conditions, turbidity of the liquid is less likely to occur, and storage stability can be further improved.
Since it has a more stable composition, it is thought that more uniform contact with the layer to be etched can be made and etching can be performed with less uneven etching.

[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 composition 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 (that is, not included).

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 (i.e., not included). be.

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 includes nitric acid, a polyvalent amine 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 optionally any of the above-mentioned compounds. It can be obtained by blending the ingredients using a known method. Therefore, in one embodiment, the present disclosure includes at least a step of blending nitric acid, a polyvalent amine 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. The present invention relates to a method for producing an etching solution composition (hereinafter also referred to as "the method for producing an etching solution of the present disclosure").
In the present disclosure, "blending at least nitric acid, a polyvalent amine 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" refers to one or more embodiments. In the step, nitric acid, a polyvalent amine 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 optionally the above-mentioned optional components are mixed simultaneously or in order. including. 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), a polyvalent amine having a number average molecular weight of 300 or more, and a nitrogen-containing basic compound having a molecular weight of less than 300. The first liquid and the second liquid are 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.

From the viewpoint of uniform etching of the layer to be etched, 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. 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 and a nitrogen-containing basic compound having a molecular weight of less than 300 (second solution). ) are not mixed with each other, and these are mixed at the time of use (two-component etching solution). 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, storing, or transporting the etching solution composition of the present disclosure at a temperature of 10° C. or lower.

In one or more embodiments, the etchant composition of the present disclosure and the etching method of the present disclosure can be used 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.

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.

1. Preparation of etching solution (Examples 1 to 6, Comparative Example 1)
Etching solutions of Examples 1 to 6 and Comparative Example 1 (pH: -1) by blending nitric acid, acids other than nitric acid (phosphoric acid, acetic acid), polyvalent amines, nitrogen-containing basic compounds, and water shown in Table 1. I got it.
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%]
PEI (polyethyleneimine) [number average molecular weight 1,800, "Epomin SP-018" manufactured by Nippon Shokubai Co., Ltd.]
Ethylenediamine [molecular weight 60.1, Fujifilm Wako Pure Chemical Industries, Ltd.]
NH ₃ (ammonia) [molecular weight 17.03, manufactured by Kishida Chemical Co., Ltd., concentration 28%]
Triethylenetetramine [molecular weight 146.23, Fujifilm Wako Pure Chemical Industries, 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 cloudy even after being allowed to stand for 48 hours or more were classified as A, those that became cloudy after more than 24 hours but less than 48 hours were designated as B, and those that became cloudy for less than 24 hours were designated as C. The results are shown in Table 1.

[Evaluation of etching unevenness of molybdenum plate]
After storing the etching solutions prepared in each composition (Examples 1 to 6 and Comparative Example 1) at 1°C for one week, a molybdenum plate of 2 cm long, 2 cm wide, and 0.1 mm thick, whose weight had been measured in advance, was added to the etching solution. 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 measuring laser microscope VK-9710 manufactured by KEYENCE (lens magnification: 150 times), and a photograph was analyzed in the surface roughness mode of the same apparatus. Then, surface accuracy, which is an index of etching unevenness, was determined using the following formula. The results are shown in Table 1. It can be determined that the smaller the surface precision value is, the more the etching unevenness is suppressed.
Surface accuracy (%) = Surface roughness after etching / Surface roughness before etching x 100

As shown in Table 1, the etching solution compositions of Examples 1 to 6 all produced turbidity even when stored at low temperatures compared to Comparative Example 1, which did not contain a nitrogen-containing basic compound with a molecular weight of less than 300. was found to be suppressed and to have excellent storage stability.
Further, in Examples 1 to 6, the relational expression (ac) ⁴ /b was 0.01 or more and 600 or less, and it was found that etching unevenness was better suppressed.

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

An etching liquid composition for etching a layer to be etched containing at least one metal, the composition comprising:
The etching liquid composition includes nitric acid, a polyvalent amine 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.
The amount of nitric acid (mass%) a, the amount of polyvalent amine having a number average molecular weight of 300 or more (mass%) b, the amount of nitrogen-containing basic compound having a molecular weight of less than 300 (mass%) c, The etching solution composition according to claim 1, wherein (ac) 4 /b≦600.
The etching liquid composition according to claim 1 or 2, further comprising an acid other than nitric acid.
The etching liquid composition according to claim 3, 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 4.
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 5.