Etching solution composition

Abstract

In one embodiment, an etching solution composition is provided that can improve the uniformity of etching on a component containing a titanium-based metal, a tungsten-based metal, a titanium-tungsten-based metal, or a nitride thereof. [Solution] In one aspect, this disclosure relates to an etching solution composition for etching a member containing a titanium-based metal, a tungsten-based metal, a titanium-tungsten-based metal, or a nitride thereof, wherein the etching solution composition comprises the following components A, B, and D, and the mass ratio A / D is 1 or more and 4 or less. Component A: Phosphate Component B: Nitric acid Component D: Aprotic polar solvent

Description

Technical Field

[0001] The present disclosure relates to an etching solution composition and an etching method using the same.

Background Art

[0002] In the manufacturing process of semiconductor devices, for example, a step of etching a member containing at least one of tungsten, titanium, titanium nitride, etc. to process it into a predetermined pattern shape is performed. In the semiconductor field in recent years, high integration has been progressing, and wiring complexity and miniaturization are required. The requirements for pattern processing technology and etching solutions are also increasing, and various etching methods and etching solutions have been proposed.

[0003] For example, Patent Document 1 proposes an etching solution suitable for both tungsten-containing metals and TiN-containing materials, which comprises at least one or two or more components selected from water, an oxidizing agent, a fluorine-containing etching compound, an organic solvent, a chelating agent, a corrosion inhibitor, and a surfactant. Patent Document 2 proposes a liquid etching solution containing a compound containing fluorine such as hydrofluoric acid, ammonium fluoride, ammonium bifluoride, fluoroboric acid, and fluorosulfonic acid; and an oxidizing agent such as nitric acid, nitrous acid, hydrogen peroxide, ozone, perchloric acid, and percarboxylic acid. The same document describes that the liquid etching solution may further contain an additive selected from inorganic oxygen-containing acids (e.g., phosphoric acid), carboxylic acids (e.g., acetic acid), aromatic carboxylic acids, hydroxycarboxylic acids, percarboxylic acids, carboxylic acid esters, carboxylic acid peresters, carboxylic acid amides, or bipolar solvents (e.g., dimethyl sulfoxide). Patent Document 3 proposes an etching composition containing 65 to 90% by weight of phosphoric acid, 0.01 to 4% by weight of acetic acid, and 0.01 to 5% by weight of nitric acid.

Prior Art Documents

Patent Documents

[0004] [Patent Document 1] Japanese Patent Publication No. 2019-165225 [Patent Document 2] Special Publication No. 2008-512862 [Patent Document 3] Special Publication No. 2022-502835 [Overview of the project] [Problems that the invention aims to solve]

[0005] A mixed acid aqueous solution (strongly acidic aqueous solution) containing phosphoric acid, nitric acid, and acetic acid is commonly used as an etching solution. However, during the etching process of components containing titanium-based metals, tungsten-based metals, titanium-tungsten-based metals, or nitrides thereof, chemical reactions such as oxidation of the titanium-based metals, tungsten-based metals, titanium-tungsten-based metals, or nitrides thereof may occur due to the etching solution. This can result in uneven etching of the surface of components containing titanium-based metals, tungsten-based metals, titanium-tungsten-based metals, or nitrides thereof, leading to the formation of an uneven surface or a halt in the etching process.

[0006] Therefore, this disclosure provides an etching solution composition that can improve the uniformity of etching on components containing titanium-based metals, tungsten-based metals, titanium-tungsten-based metals, or nitrides thereof, as well as an etching method using the same and a method for manufacturing a semiconductor substrate. [Means for solving the problem]

[0007] This disclosure relates, in one embodiment, to an etching solution composition for etching a component containing a titanium-based metal, a tungsten-based metal, a titanium-tungsten-based metal, or a nitride thereof, wherein the etching solution composition comprises the following components A, B, and D, and the mass ratio A / D is 1 or more and 4 or less. Component A: Phosphate Component B: Nitric acid Component D: Aprotic polar solvent

[0008] This disclosure relates, in one embodiment, to an etching method that includes the step of etching a member containing a titanium-based metal, a tungsten-based metal, a titanium-tungsten-based metal, or a nitride thereof using the etching solution composition of this disclosure.

[0009] This disclosure relates, in one embodiment, to a method for manufacturing a semiconductor substrate, including the etching method of this disclosure. [Effects of the Invention]

[0010] According to this disclosure, in one embodiment, an etching solution composition can be provided that can improve the uniformity of etching on a component containing a titanium-based metal, a tungsten-based metal, a titanium-tungsten-based metal, or a nitride thereof. [Modes for carrying out the invention]

[0011] As a result of diligent research by the present inventors, it has been found that by using an etching solution containing an aprotic polar solvent, the wettability to components containing titanium-based metals, tungsten-based metals, titanium-tungsten-based metals, or nitrides thereof is improved, thereby enabling good etching of the components and improving the uniformity of the etching on the components.

[0012] This disclosure relates, in one embodiment, to an etching solution composition for etching a component containing a titanium-based metal, a tungsten-based metal, a titanium-tungsten-based metal, or a nitride thereof, wherein the etching solution composition comprises the following components A, B, and D, and the mass ratio A / D is 1 or more and 4 or less (hereinafter also referred to as "the etching solution composition of Embodiment 1"). Component A: Phosphate Component B: Nitric acid Component D: Aprotic polar solvent

[0013] According to the etching solution composition of this embodiment 1, the wettability to members containing titanium-based metals, tungsten-based metals, titanium-tungsten-based metals, or nitrides thereof is improved, so that the members can be etched well and the uniformity of etching on the members can be improved. Furthermore, the smoothness and in-plane uniformity of the member surface after etching can be improved.

[0014] In other embodiments, this disclosure relates to an etching solution composition for etching a component containing a titanium-based metal, a tungsten-based metal, a titanium-tungsten-based metal, or a nitride thereof, comprising the following components A, B, C, and D, wherein the mass ratio A / D is 1 or more and 10 or less (hereinafter also referred to as "the etching solution composition of Embodiment 2"). Component A: Phosphate Component B: Nitric acid Component C: Monovalent carboxylic acid with 1 to 10 carbon atoms. Component D: Aprotic polar solvent

[0015] The etching solution of this embodiment 2 improves the wettability to members containing titanium-based metals, tungsten-based metals, titanium-tungsten-based metals, or nitrides thereof, thereby enabling good etching of the member and improving the uniformity of the etching on the member. Furthermore, it improves the smoothness and in-plane uniformity of the member surface after etching.

[0016] Although the detailed mechanism of how the effects of this disclosure are realized is not clear, it is presumed to be as follows. In etching processes for components containing titanium-based metals, tungsten-based metals, titanium-tungsten-based metals, or nitrides thereof, nitric acid in the etching solution oxidizes the component surface, and the oxidized component surface is then etched by phosphoric acid. When a chemical reaction such as oxidation of a member by nitric acid occurs, gas (bubbles) may be generated. However, when the wettability between the etching solution and the surface of a member containing a titanium-based metal, a tungsten-based metal, a titanium-tungsten-based metal, or their nitrides is low, it is considered that the detachment phenomenon of bubbles generated by the chemical reaction is unlikely to occur. When bubbles continue to adsorb on the surface of a member containing a titanium-based metal, a tungsten-based metal, a titanium-tungsten-based metal, or their nitrides, it is considered that the surface of the member is not etched uniformly, an uneven surface is formed, or the etching does not proceed. Therefore, in the present disclosure, by using an aprotic polar solvent as a wettability improver, or by using a monovalent carboxylic acid having 1 to 10 carbon atoms and an aprotic polar solvent in combination as a wettability improver, the wettability between the etching solution and a member containing a titanium-based metal, a tungsten-based metal, a titanium-tungsten-based metal, or their nitrides can be improved, the surface of the member can be etched well, and the uniformity of etching on the member can be improved. Furthermore, it is considered that the smoothness and in-plane uniformity of the surface of the member after etching can be improved. However, the present disclosure may not be construed as being limited to these mechanisms.

[0017] Hereinafter, the etching solution composition of the first aspect and the etching solution composition of the second aspect are also collectively referred to as "the etching solution composition of the present disclosure".

[0018] [Member] In one or more embodiments, the member to be etched using the etching solution composition of the present disclosure is a member containing a titanium-based metal, a tungsten-based metal, a titanium-tungsten-based metal, or their nitrides. In one or more embodiments, the member preferably includes at least one titanium-based metal selected from titanium and titanium nitride. Among these, as the member, a member containing titanium nitride is preferably mentioned. Therefore, in one or more embodiments, the etching solution composition of the present disclosure is preferably an etching solution composition for etching a member containing titanium nitride. In one or more embodiments, the member may be a layer or a film.

[0019] [Component A: Phosphoric acid] From the perspective of improving the etching rate, the content of phosphoric acid (hereinafter also referred to as "Component A") in the etching solution composition of the present disclosure is preferably 30% by mass or more, more preferably 40% by mass or more, still more preferably 50% by mass or more, and from the same perspective, it is preferably 80% by mass or less, more preferably 70% by mass or less, still more preferably 60% by mass or less. More specifically, the content of phosphoric acid (Component A) in the etching solution composition of the present disclosure is preferably 30% by mass or more and 80% by mass or less, more preferably 40% by mass or more and 70% by mass or less, still more preferably 50% by mass or more and 60% by mass or less.

[0020] [Component B: Nitric acid] From the perspective of oxidizing titanium-based metals, tungsten-based metals, titanium-tungsten-based metals or their nitrides, the content of nitric acid (hereinafter also referred to as "Component B") in the etching solution composition of the present disclosure is preferably 1% by mass or more, more preferably 1.5% by mass or more, still more preferably 2% by mass or more, and from the perspective of improving the etching rate, it is preferably 10% by mass or less, more preferably 8% by mass or less, still more preferably 5% by mass or less. More specifically, the content of nitric acid (Component B) in the etching solution composition of the present disclosure is preferably 1% by mass or more and 10% by mass or less, more preferably 1.5% by mass or more and 8% by mass or less, still more preferably 2% by mass or more and 5% by mass or less.

[0021] From the perspective of improving the etching rate, the mass ratio A / B (content of Component A / content of Component B) of Component A and Component B in the etching solution composition of the present disclosure is preferably 1 or more, more preferably 5 or more, still more preferably 10 or more, and from the perspective of oxidizing titanium-based metals, tungsten-based metals, titanium-tungsten-based metals or their nitrides, it is preferably 50 or less, more preferably 30 or less, still more preferably 28 or less. More specifically, the mass ratio A / B is preferably 1 or more and 50 or less, more preferably 5 or more and 30 or less, still more preferably 10 or more and 28 or less.

[0022] [Component C: Organic acid] The etching solution composition of this embodiment 1 may further contain an organic acid (hereinafter also referred to as "component C") in one or more embodiments. Examples of component C include at least one selected from formic acid, acetic acid, propionic acid, butyric acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, maleic acid, fumaric acid, phthalic acid, trimellitic acid, hydroxyacetic acid, lactic acid, salicylic acid, malic acid, tartaric acid, citric acid, aspartic acid, and glutamic acid. Among these, from the viewpoint of uniform etching of the layer to be etched, a monovalent organic acid having 1 to 10 carbon atoms is preferred as the organic acid, a monovalent carboxylic acid having 1 to 10 carbon atoms is more preferred, a component containing acetic acid is even more preferred, and acetic acid is even more preferred. The etching solution composition of this embodiment 2 contains, in one or more embodiments, a monovalent carboxylic acid (component C) having 1 to 10 carbon atoms. From the viewpoint of uniform etching of the layer to be etched, component C in the etching solution composition of this embodiment 2 preferably contains acetic acid, and more preferably acetic acid. In the etching solution composition of this disclosure, component C may be one type or a combination of two or more types. If the etching solution composition of this disclosure contains component C, the amount of component C in the etching solution composition of this disclosure is preferably 1% by mass or more, more preferably 2% by mass or more, even more preferably 3% by mass or more, and from the viewpoint of improving the etching rate, preferably 20% by mass or less, more preferably 15% by mass or less, and even more preferably 10% by mass or less. More specifically, the amount of component C in the etching solution composition of this disclosure is preferably 1% by mass or more and 20% by mass or less, more preferably 2% by mass or more and 15% by mass or less, and even more preferably 3% by mass or more and 10% by mass or less. If component C is a combination of two or more types, the amount of component C is the total amount of those types.

[0023] The total amount of component A and component B, or the total amount of component A, component B, and component C in the etching solution composition of this disclosure is preferably 40% by mass or more, 50% by mass or more, more preferably 55% by mass or more, and even more preferably 60% by mass or more, from the viewpoint of improving the etching rate. From the viewpoint of improving the wettability between the etching solution and the member containing titanium-based metals, tungsten-based metals, titanium-tungsten-based metals, or nitrides thereof, it is preferably 90% by mass or less, more preferably 80% by mass or less, and even more preferably 70% by mass or less. More specifically, the total amount of component A and component B, or the total amount of component A, component B, and component C in the etching solution composition of this disclosure is preferably 40% by mass or more and 90% by mass or less, or 50% by mass or more and 90% by mass or less, more preferably 55% by mass or more and 80% by mass or less, and even more preferably 60% by mass or more and 70% by mass or less.

[0024] When the etching solution composition of this disclosure contains component C, the mass ratio A / C (amount of component A / amount of component C) of component A to component C is preferably 1 or more, more preferably 5 or more, even more preferably 8 or more, and from the viewpoint of improving the etching rate, preferably 20 or less, more preferably 18 or less, and even more preferably 15 or less. More specifically, the mass ratio A / C is preferably 1 or more and 20 or less, more preferably 5 or more and 18 or less, and even more preferably 8 or more and 15 or less.

[0025] When the etching solution composition of this disclosure contains component C, the mass ratio B / C (amount of component B / amount of component C) of component B to component C is preferably 0.01 or higher, more preferably 0.1 or higher, even more preferably 0.2 or higher, and from the viewpoint of improving the etching rate, preferably 1 or lower, more preferably 0.5 or lower, and even more preferably 0.3 or lower. More specifically, the mass ratio B / C is preferably 0.01 or higher and 1 or lower, more preferably 0.1 or higher and 0.5 or lower, and even more preferably 0.2 or higher and 0.3 or lower.

[0026] [Component D: Aprotic polar solvent] Examples of the aprotic polar solvent (hereinafter also referred to as "component D") contained in the etching solution composition of this disclosure include sulfoxide solvents such as dimethyl sulfoxide (DMSO). Component D may be one type or a combination of two or more types.

[0027] The amount of component D in the etching solution composition of this disclosure is preferably 1% by mass or more, more preferably 2% by mass or more, even more preferably 5% by mass or more, even more preferably 10% by mass or more, and even more preferably 15% by mass or more, from the viewpoint of improving the wettability between the etching solution and the member containing titanium-based metals, tungsten-based metals, titanium-tungsten-based metals or nitrides thereof. More specifically, the amount of component D in the etching solution composition of this disclosure is preferably 1% by mass or more and 50% by mass or less, more preferably 2% by mass or more and 40% by mass or less, even more preferably 5% by mass or more and 30% by mass or less, even more preferably 10% by mass or more and 30% by mass or less. If component D is a combination of two or more types, the amount of component D included is the total amount of those combinations.

[0028] In the etching solution composition of this embodiment 1, the mass ratio A / D (amount of component A / amount of component D) of component A to component D is preferably 1 or more, more preferably 1.5 or more, and more preferably 2 or more, from the viewpoint of improving the wettability between the etching solution and a member containing titanium-based metals, tungsten-based metals, titanium-tungsten-based metals, or nitrides thereof, and improving the etching rate. More specifically, the mass ratio A / D is preferably 1 or more and 4 or less, more preferably 1.5 or more and 4 or less, more preferably 2 or more and 4 or less, and even more preferably 2 or more and 3 or less. In the etching solution composition of this embodiment 2, the mass ratio A / D (amount of component A / amount of component D) of component A to component D is preferably 1 or more, more preferably 1.5 or more, and more preferably 2 or more, from the viewpoint of improving the wettability between the etching solution and the member containing titanium-based metals, tungsten-based metals, titanium-tungsten-based metals or nitrides thereof, and improving the etching rate. More specifically, the mass ratio A / D is preferably 1 or more and 10 or less, more preferably 1.5 or more and 7 or less, and more preferably 2 or more and 5 or less.

[0029] In the etching solution composition of this disclosure, the mass ratio B / D (amount of component B / amount of component D) of component B to component D is preferably 0.01 or higher, more preferably 0.025 or higher, and even more preferably 0.05 or higher, from the viewpoint of improving the wettability between the etching solution and a member containing titanium-based metals, tungsten-based metals, titanium-tungsten-based metals, or nitrides thereof, and improving the etching rate. From the same viewpoint, it is preferably 1 or lower, more preferably 0.5 or lower, and even more preferably 0.3 or lower. More specifically, the mass ratio B / D is preferably 0.01 or higher and 1 or lower, more preferably 0.025 or higher and 0.5 or lower, and even more preferably 0.05 or higher and 0.3 or lower.

[0030] When the etching solution composition of this disclosure contains component C, the mass ratio C / D (amount of component C / amount of component D) of component C to component D is preferably 0.01 or higher, more preferably 0.025 or higher, and even more preferably 0.05 or higher, from the viewpoint of improving the wettability between the etching solution and the member containing titanium-based metals, tungsten-based metals, titanium-tungsten-based metals, or nitrides thereof, and improving the etching rate. From the same viewpoint, it is preferably 1 or lower, more preferably 0.75 or lower, and even more preferably 0.5 or lower. More specifically, the mass ratio C / D is preferably 0.01 or higher and 1 or lower, more preferably 0.025 or higher and 0.75 or lower, and even more preferably 0.05 or higher and 0.5 or lower.

[0031] [Ingredient E: Water] In one or more embodiments, the etching solution composition of this disclosure further comprises water (hereinafter also referred to as "component E"). Examples of component E include distilled water, deionized water, pure water, and ultrapure water. If the etching solution composition of this disclosure contains component E, the amount of component E in the etching solution composition of this disclosure is preferably 2% by mass or more, more preferably 5% by mass or more, and even more preferably 7% by mass or more, from the viewpoint of improving storage stability, and from the viewpoint of uniform etching of members containing titanium-based metals, tungsten-based metals, titanium-tungsten-based metals or nitrides thereof, it is preferably 30% by mass or less, more preferably 25% by mass or less, and even more preferably 20% by mass or less. More specifically, the amount of component E in the etching solution composition of this 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 even more preferably 7% by mass or more and 20% by mass or less.

[0032] When the etching solution composition of this disclosure contains component E, the mass ratio E / A (amount of component E / amount of component A) of component E to component A is preferably 0.1 or higher, more preferably 0.2 or higher, and even more preferably 0.3 or higher from the viewpoint of improving storage stability, and preferably 2 or lower, more preferably 1.5 or lower, and even more preferably 1 or lower from the viewpoint of improving etching rate. More specifically, the mass ratio E / A is preferably 0.1 or higher and 2 or lower, more preferably 0.2 or higher and 1.5 or lower, and even more preferably 0.3 or higher and 1 or lower.

[0033] When the etching solution composition of this disclosure contains component E, the mass ratio E / D (amount of component E / amount of component D) of component E to component D is preferably 0.1 or higher, more preferably 0.5 or higher, and even more preferably 0.8 or higher from the viewpoint of improving storage stability, and preferably 5 or lower, more preferably 2.5 or lower, and even more preferably 2 or lower from the viewpoint of improving wettability. More specifically, the mass ratio E / D (amount of component E / amount of component D) is preferably 0.1 or higher and 5 or lower, more preferably 0.5 or higher and 2.5 or lower, and even more preferably 0.8 or higher and 2 or lower.

[0034] [Other ingredients] The etching solution composition of this disclosure may further contain other components, to the extent that the effects of this disclosure are not impaired. Examples of other components include acids other than components A to C, solvents other than component D, chelating agents, surfactants, solubilizers, preservatives, rust inhibitors, disinfectants, antibacterial agents, antioxidants, and the like.

[0035] In one or more embodiments, the etching solution compositions of this disclosure may be substantially free of fluorine-containing compounds. The amount of fluorine-containing compounds in the etching solution compositions of this 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 present). In one or more embodiments of this disclosure, the present disclosure may be substantially free of azoles. The amount of azoles in the etching solution composition of this disclosure is preferably less than 0.005% by mass, more preferably 0.001% by mass or less, and even more preferably 0% by mass (i.e., not present).

[0036] [Method for producing etching solution composition] The etching solution composition of Embodiment 1 is obtained in one embodiment by blending component A, component B, component D, and optionally the above-mentioned optional components (component C, component E, and other components) in a known manner. Accordingly, this disclosure relates in one embodiment to a method for producing an etching solution composition (hereinafter also referred to as "the etching solution production method of this disclosure") which includes a step of blending at least component A, component B, and component D. The etching solution composition of Embodiment 2 is obtained in one embodiment by blending phosphoric acid (component A), nitric acid (component B), a monovalent carboxylic acid having 1 to 10 carbon atoms (component C), an aprotic polar solvent (component D), and optionally the above-mentioned optional components in a known manner. Accordingly, in other embodiments, this disclosure relates to a method for producing an etching solution composition (hereinafter also referred to as "the etching solution production method of this disclosure") which includes a step of blending at least phosphoric acid (component A), nitric acid (component B), a monovalent carboxylic acid having 1 to 10 carbon atoms (component C), and an aprotic polar solvent (component D). In this embodiment 1, "combining at least component A, component B, and component D" means, in one or more embodiments, simultaneously or sequentially mixing component A, component B, component D, and any optional component (component C, component E, or other components) as described above. In this embodiment 2, "combining at least component A, component B, component C, and component D" means, in one or more embodiments, simultaneously or sequentially mixing component A, component B, component C, component D, and any of the above-mentioned optional components as needed. The mixing order is not particularly limited. The mixture can be prepared using, for example, a propeller-type stirrer, liquid circulation stirring with a pump, a homomixer, a homogenizer, an ultrasonic disperser, and a wet ball mill. In the etching solution manufacturing method of this disclosure, the preferred blending amounts of each component can be the same as the preferred blending amounts of each component in the etching solution composition of this disclosure described above.

[0037] In this disclosure, "amount of each component in the etching solution composition" means, in one or more embodiments, the amount of each component of the etching solution composition used in the etching process, i.e., at the time of use when the etching process begins (at the time of use). The amounts of each component in the etching solution composition of this disclosure can be considered as the content of each component in the etching solution composition of this disclosure in one or more embodiments. However, the amounts of each component and the content may differ when neutralization is involved.

[0038] Embodiments of the etching solution composition of this 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 the components are mixed at the time of use. One embodiment of a two-component etching solution composition is one in which a solution containing components A and B (first solution) and a solution containing component D (second solution) are mixed at the time of use. After the first and second solutions are mixed, they may be diluted with water or an aqueous acid solution as needed. The first or second solution may contain all or part of the water used to prepare the etching solution. The first and second solutions may each contain the above-mentioned optional components (component C, component E, and other components) as needed.

[0039] In one or more embodiments, the pH of the etching solution composition of this disclosure is preferably 2 or less, and more preferably 1 or less. In one or more embodiments, the pH of the etching solution composition of this disclosure may be -2 or higher. In this disclosure, the pH of the etching solution composition is the value at 25°C and can be measured using a pH meter, specifically by the method described in the examples.

[0040] The etching solution composition of this disclosure may be stored and supplied in a concentrated state, to the extent that its stability is not impaired. This is preferable in that it can reduce manufacturing and transportation costs. This concentrated solution can then be used in the etching process after being appropriately diluted with water or an aqueous acid solution as needed. The dilution ratio can be, for example, 5 to 100 times.

[0041] [kit] In other embodiments, this disclosure relates to a kit for manufacturing the etching solution composition of this disclosure (hereinafter also referred to as the "Kit of this Disclosure"). Examples of the kits of this disclosure include a kit (two-component etching solution) that contains a solution containing components A and B (first solution) and a solution containing component D (second solution) in an unmixed state, and which are mixed at the time of use. After the first and second solutions are mixed, they may be diluted with water or an aqueous acid solution as needed. The first or second solution may contain all or part of the water used to prepare the etching solution. The first and second solutions may each contain the aforementioned optional components (component C, component E, and other components) as needed. According to the kits of this disclosure, an etching solution capable of improving the uniformity of etching on components containing titanium-based metals, tungsten-based metals, titanium-tungsten-based metals, or nitrides thereof can be prepared.

[0042] [Etching method] This disclosure relates to an etching method (hereinafter also referred to as "the etching method of this disclosure") which, in one embodiment, includes a step of etching a member containing a titanium-based metal, a tungsten-based metal, a titanium-tungsten-based metal, or a nitride thereof using the etching solution composition of this disclosure (hereinafter also referred to as "the etching step of this disclosure"). Examples of members containing a titanium-based metal, a tungsten-based metal, a titanium-tungsten-based metal, or a nitride thereof include the members described above. By using the etching method of this disclosure, in one or more embodiments, the uniformity of etching on members containing a titanium-based metal, a tungsten-based metal, a titanium-tungsten-based metal, or a nitride thereof can be improved, and the productivity of semiconductor substrates can be improved.

[0043] In the etching process of this disclosure, examples of etching methods include immersion etching and single-wafer etching.

[0044] The temperature of the etching solution composition in the etching process of this disclosure (etching temperature) is preferably 40°C or higher, more preferably 50°C or higher, even more preferably 60°C or higher, and preferably 120°C or lower, more preferably 110°C or lower, and even more preferably 100°C or lower. More specifically, the etching temperature is preferably 40°C or higher and 120°C or lower, more preferably 50°C or higher and 110°C or lower, and even more preferably 60°C or higher and 100°C or lower.

[0045] In the etching process of this disclosure, the etching time can be set, for example, to 1 minute or more and 330 minutes or less.

[0046] The etching solution compositions and etching methods of the present disclosure can be used in one or more embodiments to etch components containing titanium-based metals, tungsten-based metals, titanium-tungsten-based metals, or nitrides thereof in the manufacturing process of electronic devices, particularly semiconductor substrates. The etching solution composition and etching method of the present disclosure can be suitably used in one or more embodiments to produce at least one substrate selected from semiconductor substrates, liquid crystal display substrates, plasma display substrates, FED (Field Emission Display) substrates, optical disk substrates, magnetic disk substrates, magneto-optical disk substrates, photomask substrates, ceramic substrates, and solar cell substrates. This improves the etching performance of materials containing titanium-based metals, tungsten-based metals, titanium-tungsten-based metals, or nitrides thereof, thereby improving productivity and yield. The etching solution compositions and etching methods of the present disclosure can be used in one or more embodiments to etch electrodes in the manufacturing process of electronic devices, particularly semiconductor memories such as DRAM and non-volatile memory including NAND flash memory. The etching solution composition and etching method of this disclosure can be suitably used in one or more embodiments to produce patterns having a three-dimensional structure. This makes it possible to obtain advanced devices such as high-capacity memory. The etching solution composition and etching method of this disclosure can be used, for example, in etching methods such as those disclosed in Japanese Patent Application Publication No. 2020-145412.

[0047] [Manufacturing method for semiconductor substrates] The etching solution composition and etching method of this disclosure can be suitably used in the manufacture of semiconductor substrates. Accordingly, in one embodiment, this disclosure relates to a method for manufacturing a semiconductor substrate (hereinafter also referred to as the "method for manufacturing a semiconductor substrate of this disclosure"), including the etching method of this disclosure. In one or more embodiments, the method for manufacturing a semiconductor substrate of this disclosure includes a step of etching a substrate having a component containing a titanium-based metal, a tungsten-based metal, a titanium-tungsten-based metal, or a nitride thereof, using the etching solution composition of this disclosure. The processing method and processing conditions in the etching step are the same as those for the etching step of the etching method of this disclosure described above. In one or more embodiments, a substrate having a component containing a titanium-based metal, a tungsten-based metal, a titanium-tungsten-based metal, or a nitride thereof is a substrate having a component containing a titanium-based metal, a tungsten-based metal, a titanium-tungsten-based metal, or a nitride thereof, and an insulating component. In one or more embodiments, examples of members containing titanium-based metals, tungsten-based metals, titanium-tungsten-based metals, or nitrides thereof include the members described above, for example, titanium nitride is preferred. Examples of substrates include semiconductor substrates such as silicon wafers. Examples of insulating materials include silicon dioxide (SiO2). Examples of substrates having components containing titanium-based metals, tungsten-based metals, titanium-tungsten-based metals, or nitrides thereof include substrates in which a silicon oxide film (SiO2 film) is deposited on a silicon wafer, and a titanium nitride film (TiN film) is further deposited on the SiO2 film.

[0048] This disclosure further relates to one or more embodiments described below. <1> An etching solution composition for etching a component containing a titanium-based metal, a tungsten-based metal, a titanium-tungsten-based metal, or a nitride thereof, It contains the following ingredients A, B, and D: An etching solution composition having a mass ratio A / D of 1 or more and 4 or less. Component A: Phosphate Component B: Nitric acid Component D: Aprotic polar solvent <2> An etching solution composition for etching a component containing a titanium-based metal, a tungsten-based metal, a titanium-tungsten-based metal, or a nitride thereof, The following components A, B, C, and D are included: An etching solution composition having a mass ratio A / D of 1 or more and 10 or less. Component A: Phosphate Component B: Nitric acid Component C: Monovalent carboxylic acid with 1 to 10 carbon atoms. Component D: Aprotic polar solvent <3> It also contains organic acids (component C), <1> The etching solution composition described above. <4> This is an etching solution composition for etching components containing titanium nitride. <1> from <3> An etching solution composition as described in any of the following. <5> Component D is dimethyl sulfoxide. <1> from <4> An etching solution composition as described in any of the following. <6> The organic acid (component C) includes at least one selected from formic acid, acetic acid, propionic acid, butyric acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, maleic acid, fumaric acid, phthalic acid, trimellitic acid, hydroxyacetic acid, lactic acid, salicylic acid, malic acid, tartaric acid, citric acid, aspartic acid, and glutamic acid. <2> from <5> An etching solution composition as described in any of the following. <7> The mass ratio A / C of component A to component C is 1 or greater, or 5 or greater, or 8 or greater, and 20 or less, or 18 or less, or 15 or less. <2> from <6> An etching solution composition as described in any of the following. <8> The mass ratio A / D of component A to component D is 1 or greater, or 1.5 or greater, or 2 or greater, and 10 or less, or 4 or less, or 3 or less. <1> from <7> An etching solution composition as described in any of the following. <9> The mass ratio B / D of component B to component D is 0.01 or greater, or 0.025 or greater, or 0.05 or greater, and is 1 or less, or 0.5 or less, or 0.3 or less. <1> from <8> An etching solution composition as described in any of the following. <10> The mass ratio A / B of component A to component B is 1 or greater, or 5 or greater, or 10 or greater, and 50 or less, or 30 or less, or 28 or less. <1> from <9> An etching solution composition as described in any of the following. <11> The mass ratio C / D of component C to component D is 0.01 or greater, or 0.025 or greater, or 0.05 or greater, and is 1 or less, or 0.75 or less, or 0.5 or less. <2> from <10> An etching solution composition as described in any of the following. <12> The mass ratio B / C of component B to component C is 0.01 or greater, or 0.1 or greater, or 0.2 or greater, and 1 or less, or 0.5 or less, or 0.3 or less. <2> from <11> An etching solution composition as described in any of the following. <13> The amount of component A is 30% by mass or more, or 40% by mass or more, or 50% by mass or more, and 80% by mass or less, or 70% by mass or less, or 60% by mass or less. <1> from <12> An etching solution composition as described in any of the following. <14> The amount of component B is 1% by mass or more, or 1.5% by mass or more, or 2% by mass or more, and 10% by mass or less, or 8% by mass or less, or 5% by mass or less. <1> from <13> An etching solution composition as described in any of the following. <15> The amount of component C is 1% by mass or more, or 2% by mass or more, or 3% by mass or more, and 20% by mass or less, or 15% by mass or less, or 10% by mass or less. <2> from <14> An etching solution composition as described in any of the following. <16> The amount of component D is 1% by mass or more, or 2% by mass or more, or 5% by mass or more, or 10% by mass or more, or 15% by mass or more, and 50% by mass or less, or 40% by mass or less, or 30% by mass or less. <1> from <15> An etching solution composition as described in any of the following. <17> The total amount of component A and component B is 40% by mass or more, or 50% by mass or more, or 55% by mass or more, or 60% by mass or more, and 90% by mass or less, or 80% by mass or less, or 70% by mass or less. <1> from <16> An etching solution composition as described in any of the following. <18> The total amount of component A, component B, and component C is 40% by mass or more, or 50% by mass or more, or 55% by mass or more, or 60% by mass or more, and 90% by mass or less, or 80% by mass or less, or 70% by mass or less. <2> from <17> An etching solution composition as described in any of the following. <19> It also contains water (component E), <1> from <18> An etching solution composition as described in any of the following. <20> The mass ratio E / A of component E to component A is 0.1 or greater, or 0.2 or greater, or 0.3 or greater, and 2 or less, or 1.5 or less, or 1 or less. <1> from <19> An etching solution composition as described in any of the following. <21> The mass ratio E / D of component E to component D is 0.1 or greater, or 0.5 or greater, or 0.8 or greater, and 5 or less, or 2.5 or less, or 2 or less. <1> from <20> An etching solution composition as described in any of the following. <22> The pH is 2 or less, or 1 or less, and -2 or greater. <1> from <21> An etching solution composition as described in any of the following. <23> <1> from <22> An etching method comprising the step of etching a member containing a titanium-based metal, a tungsten-based metal, a titanium-tungsten-based metal, or a nitride thereof using an etching solution composition described in any of the above. <24> <23> A method for manufacturing a semiconductor substrate, including the etching method described above. [Examples]

[0049] The present disclosure will be specifically described below with reference to examples, but the present disclosure is not limited in any way by these examples.

[0050] 1. Preparation of etching solution (Examples 1-4, Comparative Examples 1-5) The etching solutions (pH:-1) of Examples 1-4 and Comparative Examples 1-5 were obtained by blending the components shown in Tables 1-2. Tables 1 and 2 show the amounts (mass %) and effective content of each component in the prepared etching solution. Note that the amounts of water in Tables 1 and 2 include the amount of water contained in acidic aqueous solutions, etc.

[0051] The following components were used to prepare the etching solution. (Component A) Phosphoric acid [manufactured by Phosphorus Chemical Industry Co., Ltd., concentration 85%] (Component B) Nitrate [Fujifilm Wako Pure Chemical Industries, Ltd., concentration 70%] (Component C) Acetic acid [Fujifilm Wako Pure Chemical Industries, Ltd., concentration 100%] (Component D) DMSO: Dimethyl sulfoxide [Toray Fine Chemicals Co., Ltd., 100% concentration] (Non-component D) Propylene glycol [Fujifilm Wako Pure Chemical Industries, Ltd., 100% concentration] (Component E) Water [Ultrapure water produced using a continuous pure water production system (PureConti PC-2000VRL model) and subsystem (MacAce KC-05H model) manufactured by Kurita Water Industries Ltd.]

[0052] 2. Measurement of the pH of the etching solution The pH value of the etching solution at 25°C was measured using a pH meter (manufactured by Toa DKK Co., Ltd.), and the value was obtained one minute after immersing the pH meter's electrode in the etching solution.

[0053] 3. Evaluation of etching solution The following etching tests were performed using each prepared etching solution, and the following evaluations were conducted.

[0054] [Etching test] A 1.5 × 1.5 cm TiN wafer to be etched was immersed in an etching solution heated to 70°C for a specified time (the time shown below). A water bath was used for the etching test. A glass container containing approximately 10 ml of the etching solution composition was placed in the water bath, and after standing for 30 minutes to stabilize the temperature, the TiN wafer was placed in the etching solution composition and etching was started. After etching was complete, the wafer was removed, washed with water, and then dried with air. To ensure uniform etching, the etching time was determined by the etching rate of the etching solution. The immersion time for Example 1 was 30 minutes, for Example 2 it was 21 minutes, for Example 3 it was 35 minutes, for Example 4 it was 14 minutes, for Comparative Example 1 it was 20 minutes, for Comparative Example 2 it was 17 minutes, for Comparative Example 3 it was 180 minutes, for Comparative Example 4 it was 14 minutes, and for Comparative Example 5 it was 10 minutes.

[0055] [Evaluation TiN wafer A] Evaluation TiN wafer A is a uniform blanket wafer in which an SiO2 film is deposited on a silicon wafer, and then a TiN film is deposited on top of the SiO2 film. [Evaluation TiN wafer B] Evaluation TiN wafer B is a uniform blanket wafer in which an SiO2 film is deposited on a silicon wafer, and a TiN film is further deposited on the SiO2 film using a different deposition method than wafer A.

[0056] [Calculation of etching amount and etching rate] The film thickness of wafers A and B before and after the etching test was measured by spectroscopic ellipsometry, and the difference was defined as the etching amount. The equipment and measurement conditions used are shown below. <Measurement conditions> Equipment: JAWoollam M-2000D Measurement temperature: room temperature (25℃) Measurement angles: 65°, 70°, 75° Sample size: 1.5cm square Acq. Time: 2.0 seconds Sample Thickness: 1.0mm The sample size must be larger than the light source diameter of the device. Therefore, a size of 1.0 cm square or larger is desirable, and 1.5 cm square or larger is preferable for ease of operation. The analysis was performed using CompleteEASE. The fitting model for the TiN film was TiN(LorentZ)+SiO2-JAW+INTR_JAW. The method for calculating the thickness of the TiN film is shown below. The calculation was performed by fitting the measurement results to the aforementioned fitting model under conditions where the SiO2-JAW value was fixed at 100.63 nm and the INTR_JAW value was fixed at 1.0 nm. The results are shown in Table 1. The etching rate was calculated by dividing the etching amount by the etching time. The calculation formula is shown below. Etching rate (nm / min) = Amount etched (nm) / Etching time (min)

[0057] [Contact angle measurement] The contact angles between the etching solution and TiN wafers A and B were measured using a contact angle meter. The equipment and measurement conditions used are shown below. <Measurement conditions> Equipment: DropMaster DMo-501 manufactured by Kyowa Interface Science Co., Ltd. Measurement method: Droplet method Measurement temperature: room temperature (25℃) Liquid volume: 3 μl Analysis software: FAMAS Analysis method: θ / 2 method The time from when the etching solution was applied to TiN wafers A and B until the contact angle value was read was set to 60 seconds. Five contact angle values ​​were measured, and the average of the three values ​​excluding the maximum and minimum values ​​was calculated. The results are shown in Tables 1 and 2.

[0058] [Surface roughness measurement] Etching was performed under the same conditions as in the etching test described above, and the surface roughness of TiN wafers A and B when the etching amount reached 10 nm was measured using an AFM (Digital Instrument NanoScope IIIa Multi Mode AFM). The results are shown in Table 1. A TiN wafer that was immersed in 1% BHF (buffered hydrofluoric acid solution) for 2 minutes and then washed with water was used as the blank. To verify the reliability of the obtained results, the blank TiN wafer was measured before and after etching TiN wafers A and B, and it was confirmed that the surface roughness of the blank had not changed. If the surface roughness of the blank changed by 10% or more, it was judged to be unreliable, and a remeasurement was performed. The results are shown in Tables 1 and 2. Note that in Comparative Example 3 in Table 2, the etching rate was less than 0.1 nm / min, which was not a sufficient speed for evaluation, so surface roughness was not measured. The equipment and measurement conditions used are shown below. Device: Bruker Dimension Icon Cantilever: Bruker RTESPA-300 Measurement method: Peak Force Tapping Measurement temperature: room temperature (25℃) Scan Size: 10.0 μm Scan Rate: 1.00 Hz Samples / Line:512 Analysis software: NanoScope Analysis 1.5 Roughness measurement image: Height Sensor

[0059] [Table 1]

[0060] As shown in Table 1, the etching solution composition of Example 1 showed improved wettability to titanium nitride-containing materials, as evidenced by the reduced contact angle compared to Comparative Example 1, which did not contain component D. Furthermore, Example 1 showed reduced surface roughness after etching compared to Comparative Example 1. From these findings, it is considered that the etching solution composition of Example 1 can improve the uniformity of etching to titanium nitride-containing materials by improving wettability to titanium nitride-containing materials.

[0061] [Table 2]

[0062] As shown in Table 2, the etching solution compositions of Examples 2-4, with a mass ratio A / D of 1-4, exhibited a reduced contact angle and improved wettability to titanium nitride-containing materials compared to Comparative Example 4, which had a mass ratio A / D outside the range of 1-4. Furthermore, Examples 2-4 showed reduced surface roughness after etching compared to Comparative Example 4. As mentioned above, Comparative Example 3, with a mass ratio A / D outside the range of 1-4, had an etching rate of 0.1 nm / min or less, which was not a sufficient rate for evaluation, so surface roughness was not measured. The etching solution composition of Example 2, containing components A to D, exhibited a reduced contact angle and improved wettability to titanium nitride-containing materials compared to Comparative Examples 2 and 5, which did not contain component D. Furthermore, Example 2 showed reduced surface roughness after etching compared to Comparative Examples 2 and 5. Based on these findings, it is believed that the etching solution compositions of Examples 2 to 4 can improve the uniformity of etching on titanium nitride-containing materials by improving their wettability to titanium nitride-containing materials. [Industrial applicability]

[0063] The etching solution composition of this disclosure is useful for manufacturing high-capacity semiconductor memory.

Claims

1. An etching solution composition for etching a component containing a titanium-based metal, a tungsten-based metal, a titanium-tungsten-based metal, or a nitride thereof, It contains the following components A, B, and D: An etching solution composition having a mass ratio A / D of 1 or more and 4 or less. Component A: Phosphate Component B: Nitric acid Component D: Aprotic polar solvent

2. The etching solution composition according to claim 1, which is an etching solution composition for etching a component containing titanium nitride.

3. The etching solution composition according to claim 1, wherein component D is dimethyl sulfoxide.

4. The etching solution composition according to claim 1, further comprising an organic acid (component C).

5. The etching solution composition according to claim 4, wherein the organic acid contains acetic acid.

6. The etching solution composition according to claim 1, wherein the mass ratio B / D of component B to component D is 0.01 or more and 1 or less.

7. The etching solution composition according to claim 1, wherein the mass ratio A / B of component A to component B is 1 or more and 50 or less.

8. The etching solution composition according to claim 4, wherein the mass ratio C / D of component C to component D is 0.01 or more and 1 or less.

9. The etching solution composition according to claim 1, wherein the amount of component A is 30% by mass or more and 80% by mass or less.

10. The etching solution composition according to claim 1, wherein the amount of component B is 1% by mass or more and 10% by mass or less.

11. The etching solution composition according to claim 1, wherein the amount of component D is 1% by mass or more and 50% by mass or less.

12. The etching solution composition according to claim 4, wherein the amount of component C is 1% by mass or more and 20% by mass or less.

13. The etching solution composition according to claim 1, further comprising water (component E).

14. The etching solution composition according to claim 1, wherein the pH is 2 or less.

15. An etching method comprising the step of etching a member containing a titanium-based metal, a tungsten-based metal, a titanium-tungsten-based metal, or a nitride thereof using an etching solution composition according to any one of claims 1 to 14.

16. A method for manufacturing a semiconductor substrate, comprising the etching method described in claim 15.

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