Substrate processing method and etchant composition used for the same

Abstract

To provide a substrate processing method, in one embodiment of which, it is possible to suppress a decrease in the glossiness of a metal film due to etching.SOLUTION: In one embodiment, the present invention relates to a substrate processing method that includes an etching step for etching an exposed metal film part of a substrate that has a metal film with an etchant composition, the metal film is one of a tungsten film, a molybdenum film, an osmium film, an iridium film, a ruthenium film, a rhodium film, a copper film, and a nickel film, the etchant composition including a mixed acid component, an etching inhibitor, and water, the pH of which is 1 or less, the mixed acid component being composed of phosphoric acid, nitrate, and organic acid. The etching inhibitor is at least one organic amine compound selected from a polymer having a constitutional unit derived from polyalkyleneimine or diallylamine and polyalkylene polyamine, and the mass ratio of the blending amount of the mixed acid component to the blending amount of the etching inhibitor in the etchant composition is 20 to 900 inclusive.SELECTED DRAWING: None

Description

Technical Field

[0005]

[0001] The present disclosure relates to a substrate processing method and an etching liquid composition used therefor.

Background Art

[0002] In the manufacturing process of semiconductor devices, an etching step is performed in which an etched film containing metal is etched to be processed into a predetermined pattern shape. In recent years, in the semiconductor field, high integration has been progressing, and wiring complexity and miniaturization are required. The requirements for pattern processing technology and etching liquids are also increasing, and various etching methods have been proposed.

[0003] For example, Patent Document 1 discloses that when the molar ratio (P / W) of phosphoric acid to water in a mixed acid (etching liquid) containing phosphoric acid, nitric acid, and water is controlled within a certain numerical range, fluctuations in the etching rate can be suppressed, and variations in the tungsten etching amount between multiple substrates can be reduced. Patent Document 2 discloses that in a laminate in which two types of metal films and an insulating layer are alternately laminated, when etching two types of metal films (including tungsten) between the insulating layers (for example, when etching from FIG. 1A to B), the etching rate of an etching liquid containing phosphoric acid, acetic acid, and nitric acid can be changed (for example, the etching rate can be lowered), and the two types of metal films can be efficiently etched.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] For example, using a mixed aqueous solution of phosphoric acid, acetic acid, and nitric acid as an etching solution allows for high-speed etching of films containing metals such as tungsten. On the other hand, when the aforementioned mixed acid aqueous solution was used as an etching solution, uneven etching occurred, and the glossiness of the metal film surface after etching was sometimes lost. When glossiness is lost, it can interfere with laser scattering measuring instruments, making it impossible to accurately measure surface cleanliness, shape, etc. In the semiconductor wafer manufacturing process, there is a need for an etching solution that does not easily impair glossiness from the viewpoint of productivity and yield.

[0006] Therefore, in one embodiment, this disclosure provides a substrate processing method and an etching solution composition that can suppress the decrease in glossiness of a metal film due to etching. [Means for solving the problem]

[0007] This disclosure, in one embodiment, is a substrate processing method that includes an etching step of etching an exposed portion of a metal film on a substrate having a metal film with an etching solution composition, The aforementioned metal film is one of the following: tungsten film, molybdenum film, osmium film, iridium film, ruthenium film, rhodium film, copper film, and nickel film. The etching solution composition comprises a mixed acid component, an etching inhibitor, and water, and has a pH of 1 or less. The aforementioned mixed acid component consists of phosphoric acid, organic acid, and nitric acid. The etching inhibitor is at least one organic amine compound selected from polyalkylene imines, polymers having structural units derived from diallylamine, and polyalkylene polyamines. The present invention relates to a substrate processing method in which the mass ratio of the amount of mixed acid component in the etching solution composition to the amount of etching inhibitor is 20 or more and 900 or less.

[0008] This disclosure, in one embodiment, provides an etching solution composition for use in the etching step in the substrate processing method of this disclosure, It contains mixed acid components, etching inhibitors, and water. The pH is 1 or less. The aforementioned mixed acid component consists of phosphoric acid, organic acid, and nitric acid. The etching inhibitor is at least one organic amine compound selected from polyalkylene imines, polymers having structural units derived from diallylamine, and polyalkylene polyamines. The present invention relates to an etching solution composition in which the mass ratio of the amount of mixed acid component to the amount of etching inhibitor in the etching solution composition is 20 or more and 900 or less.

[0009] In one embodiment, this disclosure relates to a method for producing an etching solution composition, comprising the step of blending a mixed acid composition containing a mixed acid component consisting of phosphoric acid, an organic acid, and nitric acid with an etching inhibitor to obtain the etching solution composition. In one embodiment, this disclosure relates to a mixed acid composition for use in the substrate processing method or the etching solution composition of this disclosure, the mixed acid composition comprising a mixed acid component consisting of phosphoric acid, an organic acid, and nitric acid. [Effects of the Invention]

[0010] According to this disclosure, in one embodiment, a substrate processing method and an etching solution composition can be provided that can suppress the decrease in glossiness of a metal film due to etching. [Brief explanation of the drawing]

[0011] [Figure 1] Figure 1 is an explanatory diagram of an example of a conventional substrate processing (etching process). [Modes for carrying out the invention]

[0012] In one aspect, the present disclosure is based on the finding that when a predetermined organic amine compound is mixed with an etching solution containing a mixed acid component composed of phosphoric acid, an organic acid, and nitric acid at a predetermined ratio with respect to the blending amount of the mixed acid component, the etching rate is suppressed without significantly impairing the handling property, and furthermore, a decrease in the glossiness of the metal film due to etching can be suppressed.

[0013] In one aspect, the present disclosure is a substrate processing method including an etching step of etching a portion of an exposed metal film of a substrate having a metal film with an etching solution composition, wherein the metal film is any one of a tungsten film, a molybdenum film, an osmium film, an iridium film, a ruthenium film, a rhodium film, a copper film, and a nickel film, the etching solution composition contains a mixed acid component, an etching inhibitor, and water, and has a pH of 1 or less, the mixed acid component is composed of phosphoric acid, an organic acid, and nitric acid, the etching inhibitor is at least one organic amine compound selected from polyalkyleneimine, a polymer having a structural unit derived from diallylamine, and polyalkylene polyamine, and relates to a substrate processing method (hereinafter, also referred to as "the substrate processing method of the present disclosure") in which the mass ratio of the blending amount of the mixed acid component in the etching solution composition to the blending amount of the etching inhibitor is 20 or more and 900 or less.

[0014] According to the substrate processing method of the present disclosure, for example, a decrease in the glossiness of the metal film due to etching can be suppressed without significantly impairing the handling property of the etching solution composition.

[0015] Although the details of the mechanism of the present disclosure's effect manifestation are not clear, it is presumed as follows. In the present disclosure, an etching solution composition is used which contains a mixed acid component composed of phosphoric acid, an organic acid, and nitric acid and an etching inhibitor, and the mass ratio of the blending amount of the mixed acid component to the blending amount of the etching inhibitor is within a predetermined range. Thereby, the etching inhibitor can form a protective film that covers the surface of the metal film, which is the film to be etched, without gaps or has a certain thickness, and gently etches while protecting the surface of the metal film. Therefore, it is considered that the progress of non-uniform etching can be suppressed and the decrease in the glossiness of the metal film due to etching can be suppressed. If the mass ratio of the blending amount of the mixed acid component to the blending amount of the etching inhibitor becomes too large, the amount of the etching inhibitor becomes small relative to the amount of the acid, so it becomes difficult to form a protective film that covers the surface of the metal film, which is the film to be etched, without gaps or has a certain thickness, and rapid etching by the acid proceeds, resulting in a rough surface and a decrease in glossiness. On the other hand, if the mass ratio of the blending amount of the mixed acid component to the blending amount of the etching inhibitor becomes too small, the decrease in glossiness can be suppressed because the amount of the etching inhibitor is sufficient relative to the amount of the acid, but it is considered that the viscosity of the etching composition increases and the handling property deteriorates. However, the present disclosure may not be construed as being limited to these mechanisms.

[0016] The substrate processing method of the present disclosure can preferably be applied to substrate processing including an etching step that requires a low etching rate because the etching rate can be controlled low by adding an etching inhibitor to an etching solution containing a mixed acid component composed of phosphoric acid, an organic acid, and nitric acid.

[0017] [Substrate Processing Method] The substrate processing method of the present disclosure includes an etching step of etching a portion of the exposed metal film of a substrate having a metal film with the etching solution composition.

[0018] [Substrate] The substrate to be processed, which is the object of the substrate processing method of the present disclosure, has a metal film that is the film to be etched. In one or more embodiments, all or part of the film to be etched of the substrate to be processed is exposed so that the etching solution can come into contact. Since the substrate processing method of this disclosure enables etching with a suppressed etching rate, substrates with a structure that prefers a low etching rate as disclosed in Patent Document 2 (for example, a substrate like the one in Figure 1A) can also be processed. In Figure 1A, 100 is a polysilicon film, 101 is a tungsten film (film to be etched), 102 is a titanium nitride film (film to be etched), and 103 is an insulating layer (SiO2 layer). The film to be etched 102 in Figure 1 may be a film other than a titanium nitride film, and the substrate may not have a film to be etched 102. Accordingly, the substrate to be processed by the substrate processing method of the present disclosure may, in one or more embodiments, be a substrate having a laminated structure in which a metal film layer containing the film to be etched and an insulating layer (e.g., an SiO2 layer) are alternately and repeatedly stacked; in one or more embodiments, be a substrate in which a part of the film to be etched is exposed; and in one or more embodiments, be a substrate in which the metal film layer is a layer containing one or more metal films.

[0019] [Metal film] The metal film to be etched on the substrate to be processed is one of tungsten film, molybdenum film, osmium film, iridium film, ruthenium film, rhodium film, copper film, and nickel film, and in one or more embodiments, it is one of tungsten film, molybdenum film, and nickel film. In this disclosure, from the viewpoint of increasing complexity and miniaturization of wiring, in one or more embodiments, the metal film is preferably a metal film containing at least one metal selected from Group 6 transition metals and Group 10 transition metals, for example, at least one selected from tungsten film, molybdenum film, and nickel film.

[0020] In one or more embodiments, if the substrate to be processed comprises a plurality of metal films, the first film may be one of tungsten film, molybdenum film, osmium film, iridium film, ruthenium film, rhodium film, copper film, and nickel film, and the second film may be one of titanium nitride film and tantalum nitride film. It is possible for the first membrane to be of multiple types. If the substrate to be processed comprises a plurality of metal films in one or more embodiments, it comprises at least one first film. In one or more embodiments, the substrate to be processed may not have a second film. Accordingly, in one or more embodiments, the substrate to be processed in the substrate processing method of the present disclosure includes a laminated structure in which metal film layers and insulating layers are alternately and repeatedly stacked, wherein the metal film layers include one or more types of metal films, and the substrate includes at least one of the following metal films: tungsten film, molybdenum film, osmium film, iridium film, ruthenium film, rhodium film, copper film, and nickel film. Furthermore, examples of substrates processed by the substrate processing method of this disclosure include, in one or more embodiments, semiconductor wafers, substrates for liquid crystal display devices, substrates for plasma displays, substrates for FEDs (Field Emission Displays), substrates for optical discs, substrates for magnetic discs, substrates for magneto-optical discs, substrates for photomasks, ceramic substrates, and substrates for solar cells.

[0021] [Etching solution composition] The etching solution composition used in the etching step of the substrate processing method of this disclosure (hereinafter also referred to as "the etching solution composition of this disclosure") contains a mixed acid component, an etching inhibitor, and water, and has a pH of 1 or less.

[0022] [Mixed acid components] The mixed acid component contained in the etching solution composition of this disclosure consists of phosphoric acid, an organic acid, and nitric acid.

[0023] [phosphoric acid] From the viewpoint of glossiness, the amount of phosphoric acid in the etching solution composition of this disclosure is preferably 35% by mass or more, more preferably 40% by mass or more, even more preferably 45% by mass or more, even more preferably 50% by mass or more, and even more preferably 55% by mass or more. From the viewpoint of glossiness, it is preferably 90% by mass or less, more preferably 85% by mass or less, and even more preferably 80% by mass or less.

[0024] [Organic acid] Examples of organic acids included in the etching solution composition of this disclosure 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. From the viewpoint of suppressing a decrease in gloss, monovalent organic acids having 1 to 10 carbon atoms are preferred, monovalent carboxylic acids having 1 to 10 carbon atoms are more preferred, and acetic acid is even more preferred. The organic acids may be used alone or in combination of two or more. From the viewpoint of etching inhibition rate, the amount of organic acid 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 etching inhibition rate, preferably 45% by mass or less, more preferably 40% by mass or less, and even more preferably 35% by mass or less. If there is a combination of two or more organic acids, the amount of organic acid is the total amount of those combined.

[0025] [nitric acid] From the viewpoint of glossiness, the amount of nitric acid in the etching solution composition of this 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, and from the viewpoint of glossiness, preferably 20% by mass or less, more preferably 10% by mass or less, and even more preferably 7% by mass or less.

[0026] For example, when the organic acid is acetic acid, in a mixed acid component consisting of phosphoric acid, acetic acid, and nitric acid, the amount of phosphoric acid is preferably 50% to 95% by mass, more preferably 60% to 93% by mass, and even more preferably 65% ​​to 90% by mass, from the viewpoint of glossiness, in one or more embodiments. The amount of phosphoric acid in the mixed acid is preferably 45% to 95% by mass, more preferably 50% to 93% by mass, and even more preferably 55% to 90% by mass, from a similar viewpoint, in one or more other embodiments. From a similar viewpoint, the amount of acetic acid in the mixed acid is preferably 2% to 80% by mass, more preferably 3% to 70% by mass, and even more preferably 5% to 60% by mass. From a similar viewpoint, the amount of nitric acid in the mixed acid is preferably 0.5% to 20% by mass, more preferably 1% to 15% by mass, and even more preferably 1.5% to 10% by mass. The mass ratio of phosphoric acid, acetic acid, and nitric acid (phosphoric acid / acetic acid / nitric acid) can be set as appropriate; for example, it can be 88 / 8 / 4.

[0027] From the viewpoint of suppressing a decrease in glossiness, the total amount of mixed acid in the etching solution composition of this disclosure is preferably 70% by mass or more, more preferably 75% by mass or more, and even more preferably 80% by mass or more. Similarly, from the viewpoint of suppressing a decrease in glossiness, it is preferably 98% by mass or less, more preferably 95% by mass or less, and even more preferably 90% by mass or less. Similarly, from the viewpoint of suppressing a decrease in glossiness, the amount of mixed acid in the etching solution composition of this disclosure is preferably 70% by mass or more and 98% by mass or less, more preferably 75% by mass or more and 95% by mass or less, and even more preferably 80% by mass or more and 90% by mass or less.

[0028] [Etching inhibitor] The etching inhibitors in this disclosure include organic amine compounds selected from polyalkylene imines, polymers having structural units derived from diallylamine, and polyalkylene polyamines. Among these, in one or more embodiments, at least one of polyalkylene imines and polyalkylene polyamines is preferred as the etching inhibitor from the viewpoint of suppressing a decrease in gloss. Examples of the polyalkyleneimines include polyethyleneimine. Examples of polymers containing the aforementioned diallylamine-derived structural units include diallylamine / sulfur dioxide copolymers. Examples of polyalkylene polyamines include triethylenetetramine and diethylenetriamine. The etching inhibitor contained in the etching solution composition of this disclosure may be used alone or in combination of two or more types.

[0029] When the etching inhibitor is a polyalkylene imine, the number-average molecular weight of the etching inhibitor is preferably 300 or more, more preferably 600 or more, and even more preferably 1,200 or more, from the viewpoint of suppressing a decrease in glossiness, and from the viewpoint of viscosity, it is preferably 100,000 or less, more preferably 5,000 or less, and even more preferably 3,000 or less. From the viewpoint of viscosity, the number-average molecular weight of the etching inhibitor is preferably 300 or more and 100,000 or less, more preferably 600 or more and 5,000 or less, and even more preferably 1,200 or more and 3,000 or less. When the etching inhibitor is a polymer containing constituent units derived from diallylamine, the weight-average molecular weight of the etching inhibitor is preferably 2,000 or more, more preferably 3,000 or more, and even more preferably 4,000 or more, from the viewpoint of suppressing a decrease in glossiness, and similarly, preferably 50,000 or less, more preferably 10,000 or less, and even more preferably 7,000 or less. From the viewpoint of viscosity, the weight-average molecular weight of the etching inhibitor is preferably 2,000 or more and 50,000 or less, more preferably 3,000 or more and 10,000 or less, and even more preferably 4,000 or more and 7,000 or less. When the etching inhibitor is a polyalkylene polyamine, the number average molecular weight or molecular weight of the etching inhibitor is preferably 50 or more, more preferably 80 or more, still more preferably 100 or more, from the viewpoint of suppressing the decrease in glossiness, and, from the same viewpoint, preferably 1,000 or less, more preferably 500 or less, still more preferably 300 or less. From the same viewpoint, the number average molecular weight or molecular weight of the etching inhibitor is preferably 50 or more and 1,000 or less, more preferably 80 or more and 500 or less, still more preferably 100 or more and 300 or less.

[0030] In the present disclosure, the average molecular weight can be measured by gel permeation chromatography (GPC).

[0031] Examples of the method for measuring the average molecular weight of the etching inhibitor of the present disclosure are shown below. <GPC conditions (polyalkyleneimine)> Sample solution: Adjusted to a concentration of 0.1 wt% Apparatus / detector: HLC-8320GPC (integrated GPC) manufactured by Tosoh Corporation Column: α-M + α-M (manufactured by Tosoh Corporation) Eluent: 0.15 mol / L Na2SO4, 1% CH3COOH / water Column temperature: 40 °C Flow rate: 1.0 mL / min Sample solution injection volume: 100 μL Standard polymer: Pullulan with known molecular weight (Shodex P-5, P-50, P-200, P-800) <GPC conditions (polymer containing structural units derived from diallylamine)> Sample solution: Adjusted to a concentration of 0.1 wt% Detector: HLC-8320GPC (integrated GPC) manufactured by Tosoh Corporation Column: α-M + α-M (manufactured by Tosoh Corporation) Eluent: 0.15 mol / L Na2SO4, 1% CH3COOH / water Column temperature: 40 °C Flow rate: 1.0 mL / min Sample solution injection volume: 100 μL Standard polymers: Pullulans with known molecular weights (Shodex P-5, P-50, P-200, P-800)

[0032] The etching inhibitor in this disclosure preferably has an etching inhibition rate of 20% or more, more preferably 30% or more, even more preferably 40% or more, even more preferably 50% or more, even more preferably 60% or more, even more preferably 70% or more, even more preferably 80% or more, even more preferably 85% or more, even more preferably 90% or more, and even more preferably 93% or more, from the viewpoint of suppressing a decrease in glossiness.

[0033] In this disclosure, etching inhibition rate refers to the rate of reduction in etching rate when an etching inhibitor is used compared to the etching rate when no etching inhibitor is used. In one or more embodiments, the etching inhibition rate can be defined as the relative etching rate A of the etching solution composition, where the etching rate of a mixed acid aqueous solution consisting of phosphoric acid, acetic acid, nitric acid, and water, wherein the mass ratio of the amounts of phosphoric acid, acetic acid, and nitric acid is the same as the mass ratio of the amounts of phosphoric acid, acetic acid, and nitric acid in the etching solution composition, and the total amount of phosphoric acid, acetic acid, and nitric acid is 85% by mass, is set to 100, and the relative etching rate A of the etching solution composition is subtracted from 100. The mass ratio of the amounts of each component in the mixed acid aqueous solution can be set as appropriate. In one or more embodiments, the etching inhibition rate can be measured by adjusting the implementation conditions such as temperature and time to match the etching conditions. The measurement conditions for the etching inhibition rate vary depending on the metal contained in the layer to be etched, and preferred ranges for temperature and time when measuring the etching inhibition rate include, in one or more embodiments, preferred ranges for etching temperature and etching time in the etching process of this disclosure described later. For example, the predetermined temperature and time for measuring the etching inhibition rate can be 90°C for 120 minutes if the metal plate used for measurement is a tungsten plate, and 40°C for 10 minutes if the metal plate used for measurement is a molybdenum plate or a nickel plate. The shape of the metal plate used for measurement can be, for example, a plate-like body with dimensions of 2 cm in length, 2 cm in width, and 0.1 mm in thickness. The etching inhibition rate can be specifically determined by the method described in the examples.

[0034] In one or more embodiments of this disclosure, the etching inhibitor is preferably an organic amine compound with an etching inhibition rate of 20% or more, from the viewpoint of suppressing a decrease in glossiness.

[0035] In one or more embodiments, the etching inhibitor in this disclosure is preferably an organic amine compound that can raise the zeta potential of the surface of the metal film to be etched to more than 0 mV and 50 mV or less, from the viewpoint of suppressing a decrease in glossiness. From the viewpoint of reducing etching unevenness, the zeta potential of the metal surface is preferably greater than 0 mV, more preferably 10 mV or more, and even more preferably 20 mV or more. The zeta potential of the metal surface may be 50 mV or less, 40 mV or less, or 35 mV or less.

[0036] The amount of etching inhibitor in the etching solution composition of this disclosure is preferably 0.05% by mass or more, more preferably 0.07% by mass or more, and even more preferably 0.09% by mass or more, from the viewpoint of suppressing the decrease in gloss and suppressing the etching rate, and from the viewpoint of good handling, it is preferably less than 5% by mass, more preferably 3% by mass or less, and even more preferably 2% by mass or less. More specifically, the amount of etching inhibitor in the etching solution composition of this disclosure is preferably 0.05% by mass or more and less than 5% by mass, more preferably 0.07% by mass or more and 3% by mass or less, and even more preferably 0.09% by mass or more and 2% by mass or less, from the viewpoint of suppressing the decrease in gloss, suppressing the etching rate, and good handling. When there is a combination of two or more etching inhibitors, the amount of etching inhibitors is the total amount of those inhibitors.

[0037] [Mass ratio: mixed acid / etching inhibitor] The mass ratio of the amount of mixed acid component to the amount of etching inhibitor in the etching solution composition of this disclosure (mixed acid / etching inhibitor) is preferably 20 or more, preferably 100 or more, and more preferably 150 or more, from the viewpoint of good handling properties, and preferably 900 or less, preferably 500 or less, and more preferably 300 or less, from the viewpoint of suppressing the decrease in gloss and suppressing the etching rate. The mass ratio (mixed acid / etching inhibitor) in the etching solution composition of this disclosure is preferably 20 or more and 900 or less, preferably 100 or more and 500 or less, and more preferably 150 or more and 300 or less, from the viewpoint of suppressing the decrease in gloss, suppressing the etching rate, and good handling properties.

[0038] [water] The etching solution compositions of this disclosure include water in one or more embodiments. Examples of water contained in the etching solution of this disclosure include distilled water, deionized water, pure water, and ultrapure water.

[0039] From the viewpoint of suppressing a decrease in glossiness, the amount of water 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. Similarly, from the viewpoint of suppressing a decrease in glossiness, it is preferably 30% by mass or less, more preferably 25% by mass or less, and even more preferably 20% by mass or less. Similarly, from the viewpoint of suppressing a decrease in glossiness, the amount of water 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.

[0040] [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 inorganic acids other than phosphoric acid and nitric acid, chelating agents, surfactants, solubilizers, preservatives, rust inhibitors, disinfectants, antibacterial agents, antioxidants, and the like.

[0041] The etching solution compositions of this disclosure are preferably hydrogen peroxide-free from the viewpoint of reducing etching unevenness. Here, "hydrogen peroxide-free" includes, in one or more embodiments, the absence of hydrogen peroxide, substantially the absence of hydrogen peroxide, or the absence of hydrogen peroxide in an amount that would affect the etching result. The amount of hydrogen peroxide blended in the etching solution compositions of this disclosure is not particularly limited, but is preferably 3% by mass or less, more preferably 1% by mass or less, even more preferably 0.1% by mass or less, even more preferably 0.01% by mass or less, and even more preferably 0% by mass.

[0042] This disclosure, in one embodiment, provides an etching solution composition for use in the etching step in the substrate processing method of this disclosure, It contains mixed acid components, etching inhibitors, and water. The pH is 1 or less. The aforementioned mixed acid component consists of phosphoric acid, organic acid, and nitric acid. The etching inhibitor is at least one organic amine compound selected from polyalkylene imines, polymers having structural units derived from diallylamine, and polyalkylene polyamines. The present invention relates to an etching solution composition in which the mass ratio of the amount of mixed acid component to the amount of etching inhibitor in the etching solution composition is 20 or more and 900 or less.

[0043] [Method for producing etching solution composition] The etching solution compositions of this disclosure are obtained in one or more embodiments by blending phosphoric acid, an organic acid, nitric acid, an etching inhibitor, water, and optionally the above-mentioned optional components in a known manner. In this disclosure, "combining at least phosphoric acid, an organic acid, nitric acid, an etching inhibitor, and water" means, in one or more embodiments, simultaneously or sequentially mixing phosphoric acid, an organic acid, nitric acid, an etching inhibitor, water, and any of the above-mentioned optional components as needed. The order of mixing is not particularly limited. The compounding can be carried out using, for example, a mixer such as a propeller-type stirrer, liquid circulation stirring with a pump, a homomixer, a homogenizer, an ultrasonic disperser, and a wet ball mill. The preferred amounts of each component can be the same as the amounts of each component in the etching solution composition of this disclosure described above.

[0044] In this disclosure, "amount of each component in the etching solution composition" means, in one or more embodiments, the amount of each component in 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.

[0045] The etching solution composition of this disclosure can be obtained in one or more embodiments by compounding a mixed acid composition containing phosphoric acid, an organic acid, and nitric acid with an etching inhibitor. Therefore, the substrate processing method of this disclosure can include in one or more embodiments a step of compounding a mixed acid composition containing a mixed acid component consisting of phosphoric acid, an organic acid, and nitric acid with an etching inhibitor to obtain the etching solution composition. In one embodiment, this disclosure relates to a method for producing the etching solution composition of this disclosure, which includes a step of compounding a mixed acid composition containing a mixed acid component consisting of phosphoric acid, an organic acid, and nitric acid with an etching inhibitor to obtain the etching solution composition of this disclosure. The mixed acid composition may contain water and, if necessary, other components as described above. The compounding of the mixed acid composition and the etching inhibitor can be carried out using the mixer described above. From the viewpoint of suppressing a decrease in glossiness, the amount of phosphoric acid in the mixed acid composition is preferably 25% by mass or more and 90% by mass or less, more preferably 30% by mass or more and 85% by mass or less, and even more preferably 35% by mass or more and 80% by mass or less. From the viewpoint of suppressing a decrease in glossiness, the amount of organic acid in the mixed acid composition is preferably 10% by mass or more and 70% by mass or less, more preferably 15% by mass or more and 65% by mass or less, and even more preferably 20% by mass or more and 60% by mass or less. From the viewpoint of suppressing a decrease in glossiness, the amount of nitric acid in the mixed acid composition is preferably 0.5% by mass or more and 20% by mass or less, more preferably 1% by mass or more and 15% by mass or less, and even more preferably 2% by mass or more and 10% by mass or less. The mass ratio of phosphoric acid, organic acid, and nitric acid in the mixed acid composition (phosphoric acid / organic acid / nitric acid) is preferably 25-90 / 8-70 / 0.5-20, more preferably 30-85 / 8-65 / 1-15, and even more preferably 35-80 / 8-60 / 2-10, from the viewpoint of suppressing a decrease in glossiness. From the viewpoint of suppressing a decrease in glossiness, the amount of water in the mixed acid composition is preferably 1% by mass or more and 30% by mass or less, more preferably 3% by mass or more and 25% by mass or less, and even more preferably 5% by mass or more and 20% by mass or less. The mixed acid composition is used in one or more embodiments to manufacture the substrate processing method or the etching solution composition of the present disclosure. Accordingly, in one embodiment, the present disclosure relates to a mixed acid composition for use in the substrate processing method or the etching solution composition of the present disclosure, comprising a mixed acid component consisting of phosphoric acid, an organic acid, and nitric acid.

[0046] 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. An example of a two-component etching solution composition is one in which water is separated into a first liquid and a second liquid, and phosphoric acid, an organic acid, nitric acid, and an etching inhibitor are contained in either one or both of the first and second liquids, respectively, and the first and second liquids are mixed at the time of use. The first and second liquids may each contain the above-mentioned optional components as needed.

[0047] From the viewpoint of suppressing a decrease in glossiness, the pH of the etching solution composition of this disclosure is preferably 1 or less, more preferably 0 or less, even more preferably less than 0, and even more preferably around -1. The pH of the etching solution composition of this disclosure can preferably be -5 or higher, and more preferably -3 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.

[0048] 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, 3 to 100 times.

[0049] [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"). The kits of this disclosure include, in one or more embodiments, a kit (two-component etching solution) that contains a first solution and a second solution in an unmixed state, with phosphoric acid, an organic acid, nitric acid, and an etching inhibitor each contained in either the first solution or the second solution, and the first solution and the second solution being mixed at the time of use. After the first solution and the second solution are mixed, they may be diluted with water or an aqueous acid solution as needed. The first solution or the second solution may contain all or part of the water used to prepare the etching solution. The first solution and the second solution may each contain the optional components described above as needed. Examples of the kits of this disclosure include a two-component etching solution containing, for example, a solution containing an etching inhibitor (Solution 1a) and a mixed acid composition containing phosphoric acid, an organic acid, and nitric acid (Solution 2a), which are mixed separately and mixed at the time of use. After Solution 1a and Solution 2a are mixed, they may be diluted with water or an aqueous acid solution as needed. Solution 1a or Solution 2a may contain all or part of the amount of water used to prepare the etching solution. The acid contained in Solution 2a may be all or part of the amount of acid used to prepare the etching solution. Solution 1a may contain an acid. Solution 1a and Solution 2a may each contain the optional components described above as needed. According to the kit of this disclosure, an etching solution composition that can be used in the substrate processing method of this disclosure can be obtained.

[0050] [Etching process] The etching step in the substrate processing method of this disclosure is a step of etching the exposed metal film portion of the substrate to be processed with the etching solution composition of this disclosure.

[0051] The etching solution composition used in the etching process of this disclosure has its etching rate controlled to a low level by an etching inhibitor, and is therefore preferably applicable to substrate processing that includes an etching process requiring a low etching rate.

[0052] In the etching process of this disclosure, examples of etching methods include immersion etching and single-wafer etching.

[0053] In one or more embodiments, when the film to be etched is a tungsten film, the temperature of the etching solution composition in the etching process of this disclosure (etching temperature) is preferably 0°C or higher, more preferably 50°C or higher, even more preferably 70°C or higher, and preferably 150°C or lower, more preferably 130°C or lower, and even more preferably 110°C or lower, from the viewpoint of suppressing a decrease in gloss. From a similar viewpoint, in one or more embodiments, when the film to be etched is a tungsten film, the etching temperature is preferably 0°C or higher and 150°C or lower, more preferably 50°C or higher and 130°C or lower, and even more preferably 70°C or higher and 110°C or lower. In one or more embodiments, when the film to be etched is a molybdenum film, the temperature of the etching solution composition in the etching process of the present disclosure (etching temperature) is preferably 0°C or higher, more preferably 15°C or higher, even more preferably 25°C or higher, and preferably 80°C or lower, more preferably 65°C or lower, and even more preferably 50°C or lower, from the viewpoint of reducing etching unevenness. From a similar viewpoint, in one or more embodiments, when the film to be etched is a molybdenum film, the etching temperature is preferably 0°C or higher and 80°C or lower, more preferably 15°C or higher and 65°C or lower, and even more preferably 25°C or higher and 50°C or lower. In one or more embodiments, when the film to be etched is a nickel film, the temperature of the etching solution composition in the etching process of the present disclosure (etching temperature) is preferably 0°C or higher, more preferably 15°C or higher, even more preferably 30°C or higher, and preferably 80°C or lower, more preferably 65°C or lower, and even more preferably 50°C or lower, from the viewpoint of reducing etching unevenness. Similarly, in one or more embodiments, when the film to be etched is a nickel film, the etching temperature is preferably 0°C or higher and 80°C or lower, more preferably 15°C or higher and 65°C or lower, and even more preferably 30°C or higher and 50°C or lower.

[0054] In the etching process of this disclosure, the etching time can be set, for example, to 1 minute or more and 180 minutes or less.

[0055] In one or more embodiments, when the film to be etched is a tungsten film, the etching rate in the etching process of this disclosure is preferably 0.0001 mg / min or more, more preferably 0.0005 mg / min or more, and even more preferably 0.001 mg / min or more, from the viewpoint of improving productivity, and preferably 10 mg / min or less, more preferably 1 mg / min or less, and even more preferably 0.1 mg / min or less, from the viewpoint of reducing etching unevenness. In one or more embodiments, when the film to be etched is a molybdenum film, the etching rate in the etching process of this disclosure is preferably 0.01 mg / min or more, more preferably 0.03 mg / min or more, and even more preferably 0.05 mg / min or more, from the viewpoint of improving productivity, and preferably 10 mg / min or less, more preferably 3 mg / min or less, and even more preferably 1 mg / min or less, from the viewpoint of reducing etching unevenness. In one or more embodiments, when the film to be etched is a nickel film, the etching rate in the etching process of this disclosure is preferably 0.001 mg / min or more, more preferably 0.005 mg / min or more, and even more preferably 0.01 mg / min or more, from the viewpoint of improving productivity, and preferably 10 mg / min or less, more preferably 1 mg / min or less, and even more preferably 0.5 mg / min or less, from the viewpoint of reducing etching unevenness.

[0056] The substrate processing method and etching solution composition of the present disclosure can be used in one or more embodiments to etch a substrate in the manufacturing process of electronic devices, particularly semiconductor wafers. The substrate processing method and etching solution composition of the present disclosure can be suitably used in one or more embodiments to produce at least one substrate selected from semiconductor wafers, liquid crystal display substrates, plasma display substrates, FED (Field Emission Display) substrates, optical disk substrates, magnetic disk substrates, magneto-optical disk substrates, photomask substrates, ceramic substrates, and solar cell substrates. According to the substrate processing method of this disclosure, in one or more embodiments, the decrease in glossiness of the metal film due to etching can be suppressed, and productivity and yield can be improved. According to the substrate processing method of this disclosure, in one or more embodiments, the etching rate can be suppressed, and productivity and yield can be improved. The substrate processing method and etching solution composition 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 non-volatile memories including NAND flash memory. The substrate processing method and etching solution composition 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 substrate processing method and etching solution composition of this disclosure can be used, for example, in etching methods such as those disclosed in Japanese Patent Application Publication No. 2020-145412 (Patent Document 2). [Examples]

[0057] 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.

[0058] 1. Preparation of etching solution (Examples 1-6, Comparative Examples 1-3) Etching solutions (pH: -1) for Examples 1-6 and Comparative Examples 1-3 were obtained by combining the etching inhibitors shown in Table 1, mixed acid (phosphoric acid / acetic acid / nitric acid, mass ratio: 88 / 8 / 4), and water. The mass ratio of the mixed acid is calculated on a mass basis. Table 1 shows the proportions (mass %) and effective content of each component in the prepared etching solution. Note that the proportion of water in Table 1 includes the amount of water contained in acidic aqueous solutions, etc.

[0059] The following components were used to prepare the etching solution. Phosphoric acid [manufactured by Phosphorus Chemical Industry Co., Ltd., concentration 85%] Nitric acid [Fujifilm Wako Pure Chemical Industries, Ltd., 70% concentration] (organic acid) Acetic acid [Fujifilm Wako Pure Chemical Industries, Ltd., 100% concentration] (Etching inhibitor) Polyethyleneimine [Number average molecular weight 1,800, "Epomin SP-018" manufactured by Nippon Shokubai Co., Ltd.] Triethylenetetramine [Molecular weight 146, manufactured by Tosoh Corporation as "TETA"] (water) 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.]

[0060] 2. Method for measuring the pH of etching solution The pH value of the etching solution 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 at 25°C.

[0061] 3. Method for measuring the viscosity of etching solution The viscosity of the etching solution was measured using the following viscometer under the following conditions. Device name: TVB-10 viscometer (with constant temperature bath) manufactured by Toki Sangyo Co., Ltd. Rotor: Spindle No. M1, Cord No. 20 Viscosity value measured at rotation speed: 100 rpm, after 60 seconds. Measurement temperature: 25℃

[0062] 4. Evaluation of etching solution [Evaluation of etching rate and etching suppression rate of tungsten plates] Tungsten plates, measuring 2 cm in length, 2 cm in width, and 0.1 mm in thickness, whose weight had been measured beforehand, were immersed in etching solutions prepared for each composition (Examples 1-6 and Comparative Examples 1-3). The tungsten plates were etched at 90°C for 120 minutes. After rinsing with water, the weight of the tungsten plates was measured again, and the difference was determined as the etching amount. A precision balance was used to measure the weight. The etching rate was then determined using the following formula. Etching rate (mg / min) = Amount of etching (mg) / Etching time (min) The etching rate results for the tungsten plate are shown in Table 1. Furthermore, the etching suppression rate (%) for each example, obtained by subtracting the etching rate of the tungsten plate in Comparative Example 1 (set to 100) from 100, is also shown in Table 1. [Evaluation of etching rate and etching suppression rate of nickel plates] The nickel plate was etched in the same manner as the tungsten plate, except that a nickel plate measuring 2 cm in length, 2 cm in width, and 0.1 mm in thickness was used instead of the tungsten plate, and the etching conditions were changed to an etching temperature of 40°C and an etching time of 10 minutes. The etching rate of the nickel plate was then measured. The results of the etching rate of the nickel plate are shown in Table 1. Furthermore, the etching inhibition rate (%) was calculated by subtracting the relative etching rate of each example from 100, with the etching rate of the nickel plate in Comparative Example 1 set to 100, and this value is also shown in Table 1.

[0063] [Evaluation of glossiness] The appearance of the tungsten and nickel plates after etching with each etching solution was visually inspected, and the glossiness after etching was evaluated according to the following criteria. The results are shown in Table 1. <Evaluation Criteria> 5: The entire surface of the board is mirror-like. 4: Most of the board is mirror-like, but some signs of corrosion are visible. 3: Half of the board is mirror-like, but the other half shows signs of corrosion. 2: Most of the boards show signs of corrosion. 1: The entire surface of the board is cloudy and has no mirror-like surface at all.

[0064] [Evaluation of handling performance] The handling characteristics of each etching solution were evaluated based on the following criteria, and the results are shown in Table 1. <Evaluation Criteria> ○: Easy to handle △: High viscosity limits the types of pumps and other equipment that can be used.

[0065] [Table 1]

[0066] As shown in Table 1, the etching solutions of Examples 1 to 6, which contain etching inhibitors, showed slower etching rates for tungsten and nickel plates, suppressed reduction in gloss due to etching, and had better handling properties compared to Comparative Examples 1 to 3, which do not contain etching inhibitors. [Industrial applicability]

[0067] The substrate processing method of this disclosure is useful, for example, in the manufacture of semiconductor wafers, substrates for liquid crystal display devices, substrates for plasma displays, substrates for FEDs (Field Emission Displays), substrates for optical discs, substrates for magnetic discs, substrates for magneto-optical discs, substrates for photomasks, ceramic substrates, and substrates for solar cells.

Claims

1. A substrate processing method including an etching step of etching an exposed portion of a metal film of a substrate having a metal film with an etching liquid composition, wherein the metal film is any one of a tungsten film, a molybdenum film, an osmium film, an iridium film, a ruthenium film, a rhodium film, a copper film, and a nickel film, wherein the etching liquid composition contains a mixed acid component, an etching inhibitor, and water, and has a pH of 1 or less, wherein the mixed acid component consists of phosphoric acid, an organic acid, and nitric acid, wherein the etching inhibitor is at least one organic amine compound selected from polyalkyleneimine, a polymer having a structural unit derived from diallylamine, and polyalkylene polyamine, A substrate processing method, wherein a mass ratio of a blending amount of the mixed acid component in the etching liquid composition to a blending amount of the etching inhibitor is 20 or more and 900 or less.

2. The substrate processing method according to claim 1, including a step of obtaining the etching liquid composition by blending a mixed acid composition containing a mixed acid component consisting of phosphoric acid, an organic acid, and nitric acid and an etching inhibitor.

3. wherein the substrate includes a laminate structure in which a metal film layer and an insulating layer are alternately and repeatedly laminated, wherein the metal film layer includes one or more types of metal films and includes at least any one of a tungsten film, a molybdenum film, an osmium film, an iridium film, a ruthenium film, a rhodium film, a copper film, and a nickel film, the substrate processing method according to claim 1.

4. The substrate processing method according to claim 1, wherein the etching liquid composition does not contain hydrogen peroxide.

5. The substrate according to claim 1 is at least one substrate selected from a semiconductor wafer, a substrate for a liquid crystal display device, a substrate for a plasma display, a substrate for an FED (Field Emission Display), a substrate for an optical disk, a substrate for a magnetic disk, a substrate for a magneto-optical disk, a substrate for a photomask, a ceramic substrate, and a substrate for a solar cell.

6. An etching liquid composition for use in the etching step in the substrate processing method according to claim 1, comprising a mixed acid component, an etching inhibitor, and water, having a pH of 1 or less, wherein the mixed acid component consists of phosphoric acid, an organic acid, and nitric acid, wherein the etching inhibitor is at least one organic amine compound selected from polyalkyleneimine, a polymer having a structural unit derived from diallylamine, and polyalkylene polyamine, An etching liquid composition, wherein the mass ratio of the blending amount of the mixed acid component in the etching liquid composition to the blending amount of the etching inhibitor is 20 or more and 900 or less.

7. A method for producing the etching liquid composition according to claim 6, comprising a step of obtaining the etching liquid composition by blending a mixed acid composition containing a mixed acid component consisting of phosphoric acid, an organic acid, and nitric acid with an etching inhibitor.

8. A mixed acid composition for use in the substrate processing method according to any one of claims 2 to 5 or the method for producing the etching liquid composition according to claim 7, comprising a mixed acid component consisting of phosphoric acid, an organic acid, and nitric acid.

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