Etching composition

Abstract

This disclosure relates to an etching composition that is useful, for example, as an intermediate step in a multi-stage semiconductor manufacturing process for selectively removing hafnium oxide from a semiconductor substrate.

Description

Technical Field

[0001] Cross - reference to related applications This application claims the priority of U.S. Provisional Patent Application No. 63 / 457,841, filed on April 7, 2023, the entire content of which is incorporated herein by reference.

[0002] This disclosure relates to an etching composition and a process using the etching composition. In particular, the disclosure relates to an etching composition capable of selectively etching hafnium oxide in the presence of other exposed materials or underlying materials such as metal conductors (e.g., copper), gate materials (e.g., SiGe), barrier materials, and insulator materials (e.g., low - k dielectric materials).

Background Art

[0003] In the semiconductor industry, miniaturization and high - density integration of electronic circuits and components in microelectronics devices, silicon chips, memory chips, liquid crystal displays, MEMS (Micro - Electro - Mechanical Systems), printed circuit boards, etc. are rapidly progressing. The integrated circuits among them have a layer structure or a stacked structure, and the insulating layers between each circuit layer are continuously thinned. As the feature size is reduced, the pattern becomes smaller, and the performance parameters of the device have become more stringent and non - negotiable. As a result, various problems that were previously acceptable have become unacceptable or have become increasingly problematic due to the reduction of the feature size.

[0004] In the manufacture of highly integrated circuits, both high - k and low - k insulators, as well as various barrier layer materials, have been used to minimize problems associated with high - density integration and optimize performance.

[0005] Hafnium oxide (HfOx) can be used in the manufacture of semiconductor devices, liquid crystal displays, MEMS (micro-electromechanical systems), and printed circuit boards. Hafnium oxide often needs to be removed during the etching process in the presence of other exposed or underlying materials in the semiconductor substrate. [Overview of the project] [Problems that the invention aims to solve]

[0006] In the construction of semiconductor devices, hafnium oxide (HfOx, such as HfO2) often needs to be etched. In various uses of HfOx and in different device environments, this material is etched simultaneously with other layers being in contact or otherwise exposed. For device yield and long lifespan, highly selective etching of HfOx in the presence of these other materials (e.g., metallic conductors, dielectrics, channel materials, gate materials, and hard masks) is usually required.

[0007] This disclosure relates to compositions for selectively etching HfOx against hard mask layers (e.g., SiOx), gate materials (e.g., SiGe or SiOx), and / or low-k dielectric layers (e.g., SiOx, carbon-doped oxides, SiCO, or silicon oxycarbonitride (SiOCN)) present in semiconductor devices, and to processes using the etching compositions described herein. More specifically, this disclosure relates to compositions and processes for selectively etching HfOx against SiOx. [Means for solving the problem]

[0008] In one embodiment, the present disclosure describes an etching composition comprising: (1) at least one first acid or salt thereof containing a fluorine-containing inorganic acid; (2) at least one second acid having a pKa of about 3 or less, different from the at least one first acid; (3) at least one organic solvent having a logP of about -0.2 to about 1.6; and (4) water.

[0009] In another aspect, the disclosure describes an etching composition comprising: (1) at least one first acid or salt thereof containing a fluorine-containing inorganic acid; (2) at least one second acid having a pKa of about 3 or less, unlike the at least one first acid; (3) at least one organic solvent having a ClogP of about -0.3 to about 1.6; and (4) water.

[0010] In another embodiment, the present disclosure features a method for substantially removing a hafnium oxide film (e.g., contained within an HfOx-containing feature) by contacting a semiconductor substrate supporting the hafnium oxide film with an etching composition described herein.

[0011] In yet another aspect, the disclosure features an article which is a semiconductor device (e.g., an integrated circuit) formed by the method described above. [Modes for carrying out the invention]

[0012] As defined herein, unless otherwise specified, all percentages expressed should be understood as weight percentages of the total weight of the composition. Where used herein, the terms “layer” and “film” are interchangeable.

[0013] In general, this disclosure describes etching compositions (e.g., etching compositions for selectively removing HfOx) comprising (1) at least one first acid or salt thereof comprising a fluorine-containing inorganic acid; (2) at least one second acid having a pKa of about 3 or less, different from at least one first acid; (3) at least one organic solvent having a logP of about -0.2 to about 1.6; and (4) water. In some embodiments, the etching composition contains only these four components.

[0014] In some embodiments, the disclosure describes an etching composition comprising: (1) at least one first acid or salt thereof containing a fluorine-containing inorganic acid; (2) at least one second acid having a pKa of about 3 or less, different from at least one first acid; (3) at least one organic solvent having a ClogP of about -0.3 to about 1.6; and (4) water. In some embodiments, the etching composition contains only these four components.

[0015] In some embodiments, the etching composition of the present disclosure comprises at least one (e.g., two, three, or four) first acid or a salt thereof. In some embodiments, the first acid may be a fluorine-containing inorganic acid. In some embodiments, the first acid or a salt thereof may be hydrofluoric acid (HF), ammonium fluoride (NH4F), ammonium hydrogen fluoride (NH4F·HF), tetramethylammonium fluoride (TMAF), hexafluorosilicic acid (H2SiF6), hexafluorophosphate (HPF6), or tetrafluoroboric acid (HBF4). While not theoretically bound, the first acid is thought to facilitate the removal of HfOx from the semiconductor substrate during the etching process and to enhance the etching selectivity of HfOx.

[0016] In some embodiments, the first acid contained in the etching composition described herein may be present in an amount that, in combination with other materials of the etching composition, provides desired etching performance (e.g., desired HfOx etching rate and selectivity). In some embodiments, the amount of the first acid is about 0.1% by weight or more (e.g., about 0.2% by weight or more, about 0.4% by weight or more, about 0.5% by weight or more, about 0.6% by weight or more, about 0.8% by weight or more, about 1% by weight or more, about 1.2% by weight or more, about 1.4% by weight or more, about 1.5% by weight or more, about 1.6% by weight or more, about 1.8% by weight or more, or about 2% by weight or more) or about 5% by weight or less (e.g., about 4.5% by weight or less, about 4% by weight or less, about 3.5% by weight or less, about 3% by weight or less, about 2.8% by weight or less, about 2.6% by weight or less, about 2.5% by weight or less, about 2.4% by weight or less, about 2.2% by weight or less, or about 2% by weight or less) relative to the etching composition described herein.

[0017] In some embodiments, the etching compositions of the present disclosure may contain at least one (e.g., two, three, or four) second acid distinct from the first acid. In some embodiments, the second acid is a strong acid and has a pKa in the range of about 3 or less (e.g., about 2.5 or less, about 2 or less, about 1.5 or less, about 1 or less, about 0.5 or less, or about 0 or less) and about -10 or more (e.g., about -9 or more, about -8 or more, about -7 or more, about -6 or more, or about -5 or more). In some embodiments, the second acid does not contain a fluorine atom. In some embodiments, the second acid may be an inorganic acid (e.g., hydrochloric acid, hydrobromic acid, nitric acid, phosphoric acid, sulfuric acid) or an organic acid (e.g., sulfonic acid). While not theoretically bound, the second acid is thought to be able to maintain the pH of the etching composition at a low level and enhance the etching selectivity of HfOx.

[0018] In some embodiments, the etching compositions of the present disclosure include at least one (e.g., two, three, or four) organic solvents. In some embodiments, the organic solvents may have a ClogP (representing the partition coefficient) in the range of about -0.3 or higher (e.g., about -0.2 or higher, about -0.15 or higher, about -0.1 or higher, about -0.05 or higher, about 0 or higher, about 0.05 or higher, about 0.1 or higher, about 0.15 or higher, about 0.2 or higher, about 0.25 or higher, or about 0.3 or higher) and about 1.6 or lower (e.g., about 1.5 or lower, about 1.4 or lower, about 1.2 or lower, about 1 or lower, about 0.9 or lower, about 0.8 or lower, about 0.7 or lower, about 0.6 or lower, about 0.5 or lower, or about 0.4 or lower). Examples of organic solvents having the above ClogP values ​​include alcohols such as ethanol, isopropanol, ethylene glycol monobutyl ether, 3-methoxy-3-methyl-1-butanol, benzyl alcohol, diethylene glycol monobutyl ether, and 4-methyl-2-pentanol; ketones such as cyclohexanone; and ethers such as tetrahydrofuran. When used herein, the above ClogP values ​​are calculated using the software ChemDraw and are summarized in Table 1 below. [Table 1]

[0019] While not bound by theory, organic solvents with ClogP within the above range are thought to be able to improve HfOx / SiOx etching selectivity.

[0020] In some embodiments, the amount of the organic solvent is about 80% by weight or more (e.g., about 82% by weight or more, about 84% by weight or more, about 85% by weight or more, about 86% by weight or more, about 88% by weight or more, about 90% by weight or more, about 92% by weight or more, about 94% by weight or more, or about 95% by weight or more) or about 99% by weight or less (e.g., about 98% by weight or less, about 97% by weight or less, about 96% by weight or less, or about 95% by weight or less) relative to the etching composition described herein.

[0021] In general, the etching compositions of this disclosure may contain water as a solvent. In some embodiments, the water may be deionized water and ultrapure water, water free of organic contaminants, and / or water having a minimum resistivity of about 4 to about 17 megaohms or at least about 17 megaohms. In some embodiments, the amount of water is about 0.01% by weight or more (e.g., about 0.05% by weight or more, about 0.1% by weight or more, about 0.5% by weight or more, about 1% by weight or more, about 1.5% by weight or more, about 2% by weight or more, about 2.5% by weight or more, or about 3% by weight or more) and about 10% by weight or less (e.g., about 9% by weight or less, about 8% by weight or less, about 7% by weight or less, about 6% by weight or less, about 5% by weight or less, or about 4% by weight or less) relative to the etching composition. Although not theoretically bound, it is thought that if the amount of water exceeds 10% by weight of the composition, the HfOx / SiOx etching selectivity will decrease. On the other hand, although not bound by theory, it is considered that the etching composition of this disclosure should contain a certain level of water (e.g., about 0.01% by weight or more) in order to avoid a decrease in etching performance.

[0022] In some embodiments, the etching compositions of this disclosure may have a pH of about 0 or higher (e.g., about 0.2 or higher, about 0.4 or higher, about 0.5 or higher, about 0.6 or higher, about 0.8 or higher, about 1 or higher, about 1.2 or higher, about 1.4 or higher, or about 1.5 or higher) and / or about 2 or lower (e.g., about 1.8 or lower, about 1.6 or lower, about 1.5 or lower, about 1.4 or lower, about 1.2 or lower, about 1 or lower, about 0.8 or lower, about 0.6 or lower, or about 0.5 or lower). Not limited to theory, etching compositions with a pH below 0 are thought to cause significant corrosion to other materials on the substrate. Furthermore, not limited to theory, etching compositions with a pH greater than 2 are thought to lack a sufficient HfOx removal rate.

[0023] In some embodiments, the cleaning composition of the present disclosure may optionally include at least one (e.g., two, three, or four) pH adjuster (e.g., an acid or a base) to adjust the pH to about 0 to about 2. When a pH adjuster is required, the amount of the required pH adjuster may vary depending on the concentrations of other components (e.g., the first and second acids described herein) varying in various formulations. In some embodiments, the pH adjuster may be about 0.1 wt% or more (e.g., about 0.2 wt% or more, about 0.4 wt% or more, about 0.5 wt% or more, about 0.6 wt% or more, about 0.8 wt% or more, about 1 wt% or more, about 1.2 wt% or more, about 1.4 wt% or more, or about 1.5 wt% or more) and / or about 3 wt% or less (e.g., about 2.8 wt% or less, about 2.6 wt% or less, about 2.5 wt% or less, about 2.4 wt% or less, about 2.2 wt% or less, about 2 wt% or less, or about 1.8 wt% or less) with respect to the etching composition. In some embodiments, the etching composition of the present disclosure may not substantially contain a pH adjuster.

[0024] In some embodiments, the pH adjuster is free of metal ions (excluding trace metal ion impurities). Suitable metal ion-free pH adjusters include acids and bases. Suitable acids that can be used as pH adjusters include organic acids (e.g., carboxylic acids) and inorganic acids. Exemplary carboxylic acids include monocarboxylic acids, dicarboxylic acids, tricarboxylic acids, α-hydroxy acids and β-hydroxy acids of monocarboxylic acids, α-hydroxy acids or β-hydroxy acids of dicarboxylic acids, or α-hydroxy acids and β-hydroxy acids of tricarboxylic acids, but are not limited thereto. Examples of suitable carboxylic acids include citric acid, maleic acid, fumaric acid, lactic acid, glycolic acid, oxalic acid, tartaric acid, succinic acid, and benzoic acid. Examples of suitable inorganic acids include phosphoric acid, nitric acid, sulfuric acid, and hydrochloric acid.

[0025] Suitable bases that can be used as pH adjusters include ammonium hydroxide, monoamines (including alkanolamines), and cyclic amines. Examples of suitable monoamines include, but are not limited to, triethylamine, tributylamine, tripentylamine, diethylamine, butylamine, dibutylamine, and benzylamine. Examples of suitable alkanolamines include, but are not limited to, monoethanolamine, diethanolamine, triethanolamine, and aminopropyldiethanolamine. Examples of suitable cyclic amines include, but are not limited to, 1,8-diazabicyclo[5.4.0]-7-undecene (DBU), 1,5-diazabicyclo[4.3.0]-5-nonene (DBN), and octahydro-2H-quinolizine.

[0026] In some embodiments, the etching composition of the present disclosure may contain additives such as a pH adjuster, a corrosion inhibitor, a surfactant, an additional organic solvent, a biocide, and an antifoaming agent as optional components. Examples of some suitable additives include alcohols (e.g., polyvinyl alcohol and sugar alcohols). Examples of suitable antifoaming agents include polysiloxane antifoaming agents (e.g., polydimethylsiloxane), polyethylene glycol methyl ether polymers, ethylene oxide / propylene oxide copolymers, and glycidyl ether-terminated acetylene diol ethoxylates (such as those described in U.S. Patent No. 6,717,019, which is incorporated herein by reference). Examples of suitable surfactants may be cationic, anionic, nonionic, and amphoteric surfactants.

[0027] In general, the etching compositions of this disclosure can have relatively high HfOx removal rates. In some embodiments, when an HfOx film is treated with the etching composition, the etching composition may have an HfOx removal rate of about 0.5 Å / min or more (e.g., about 1 Å / min or more, about 2 Å / min or more, about Å / min or more, about 5 Å / min or more, about 10 Å / min or more, about 15 Å / min or more, about 20 Å / min or more, about 25 Å / min or more, about 30 Å / min or more, about 35 Å / min or more, or about 40 Å / min or more), or about 100 Å / min or less (e.g., about 90 Å / min or less, about 80 Å / min or less, about 70 Å / min or less, about 60 Å / min or less, or about 50 Å / min or less).

[0028] In general, the etching compositions of this disclosure can have relatively low SiOx removal rates (e.g., SiOx removal rates lower than HfOx removal rates). In some embodiments, when a SiOx film is treated with the etching composition, the etching composition may have SiOx removal rates of about 0.5 Å / min or more (e.g., about 1 Å / min or more, about 2 Å / min or more, about Å / min or more, about 5 Å / min or more, about 10 Å / min or more, about 15 Å / min or more, about 20 Å / min or more, about 25 Å / min or more, about 30 Å / min or more, about 35 Å / min or more, or about 40 Å / min or more), or about 100 Å / min or less (e.g., about 90 Å / min or less, about 80 Å / min or less, about 70 Å / min or less, about 60 Å / min or less, or about 50 Å / min or less).

[0029] In general, the etching compositions of this disclosure can have relatively high HfOx / dielectric material (e.g., SiOx such as SiO2, or SiOCN) removal rate selectivity (i.e., a high ratio of HfOx removal rate to dielectric material removal rate). In some embodiments, the etching compositions may have a SiN / SiOx removal rate selectivity of about 1 or more (e.g., about 1.5 or more, about 2 or more, about 2.5 or more, about 3 or more, about 3.5 or more, about 4 or more, about 4.5 or more, or about 5 or more) and / or about 10 or less (e.g., about 9 or less, about 8 or less, about 7 or less, about 6 or less, or about 5 or less) when the etching rates of HfOx and SiOx are measured under the same conditions (e.g., the same etching temperature).

[0030] In some embodiments, the etching compositions of the present disclosure may substantially omit one or more additive components, or any combination of two or more. Such components include polymers (e.g., nonionic, cationic, or anionic polymers), oxygen scavengers, quaternary ammonium compounds (e.g., salts or hydroxides), alkaline bases (NaOH, KOH, LiOH, Mg(OH)2, and Ca(OH)2, etc.), surfactants (e.g., cationic, anionic, or nonionic surfactants), defoamers, fluorine-containing compounds other than fluorine-containing inorganic acids or their salts (e.g., fluoride compounds or fluorinated compounds (fluorinated polymers / fluorinated surfactants, etc.)), silicon-containing compounds such as silanes other than those described herein (e.g., alkoxysilanes), nitrogen-containing compounds other than those described herein (e.g., amino acids, amines, imines (e.g., amidines such as 1,8-diazabicyclo[5.4.0]-7-undecene (DBU) and 1,5-diazabicyclo[4.3.0]nona-5-ene (DBN)), amides, or imides), abrasives (e.g., The following are selected from the group consisting of ceria abrasives, nonionic abrasives, surface modifying abrasives, negative / positive charged abrasives, or ceramic abrasive composites), plasticizers, oxidizing agents (e.g., peroxides such as hydrogen peroxide and periodic acid), corrosion inhibitors (e.g., azole or non-azole corrosion inhibitors), electrolytes (e.g., polymer electrolytes), silicates, cyclic compounds other than those described herein (e.g., azoles (diazole, triazole, or tetrazole, etc.); triazines; and cyclic compounds containing at least two rings, such as substituted or unsubstituted naphthalenes, or substituted or unsubstituted biphenyl ethers), chelating agents or complexing agents, buffering agents, acids such as organic acids (e.g., carboxylic acids such as hydroxycarboxylic acids and polycarboxylic acids, and sulfonic acids) and inorganic acids (e.g., sulfuric acid, sulfite, nitrite, nitric acid, phosphorous acid, and phosphoric acid), salts (e.g., halide salts or metal salts), and catalysts (e.g., metal-containing catalysts). In some embodiments, the composition is substantially free of oxidizing agents, complexing agents, surfactants, or amines. As used herein, the term "substantially absent" of an etching composition means a component that is not intentionally added to the etching composition.In some embodiments, the etching compositions described herein may contain one or more of the above components that are substantially absent from the etching compositions in amounts of about 1000 ppm or less (e.g., about 500 ppm or less, about 250 ppm or less, about 100 ppm or less, about 50 ppm or less, about 10 ppm or less, or about 1 ppm or less). In some embodiments, the etching compositions described herein may not contain one or more of the above components at all.

[0031] The etching compositions of this disclosure may be prepared simply by mixing the components together, or by blending two or more compositions contained in the kit (each containing specific components of the etching compositions described herein).

[0032] In some embodiments, the Disclosure describes a method for etching a semiconductor substrate containing an HfOx film (e.g., present in an HfOx-containing feature). The method may include contacting the semiconductor substrate containing the HfOx film with an etching composition described herein to substantially remove the HfOx film. In some embodiments, the semiconductor substrate may include patterns or features on its surface, and the HfOx film is part of the pattern or features. In some embodiments, the method may further include rinsing the semiconductor substrate with a rinsing solvent after the contact step and / or drying the semiconductor substrate after the rinsing step.

[0033] In some embodiments, the contact process may be carried out at room temperature (i.e., 23°C) or at a higher temperature. For example, the contact process may be carried out at a temperature within the range of approximately 23°C or higher (e.g., approximately 25°C or higher, approximately 30°C or higher, approximately 35°C or higher, or approximately 40°C or higher) and approximately 50°C or lower (e.g., approximately 45°C or lower, approximately 40°C or lower, approximately 35°C or lower, or approximately 30°C or lower). Although not theoretically bound, it is believed that carrying out the contact process at a higher temperature (e.g., within the above range) can increase the HfOx etching rate of the etching composition.

[0034] In some embodiments, the method does not substantially remove metallic conductors (e.g., Cu) or dielectric materials (e.g., SiOx or SiOCN) present in the semiconductor substrate. For example, the method does not remove more than about 5% by weight of metallic conductors or dielectric materials present in the semiconductor substrate (e.g., not more than about 3% by weight, or not more than about 1% by weight).

[0035] In some embodiments, the etching method is (A) A step of providing a semiconductor substrate including an HfOx film (e.g., an HfOx film in a pattern or feature), (B) A step of bringing a semiconductor substrate into contact with the etching composition described herein, (C) A step of rinsing the semiconductor substrate with one or more suitable rinsing solvents, (D) Optionally, a step of drying the semiconductor substrate (e.g., by any appropriate means that does not impair the integrity of the semiconductor substrate), Includes.

[0036] The semiconductor substrate etched using this method may contain organic and organometallic residues, as well as various metal oxides, some or all of which can be removed during the etching process.

[0037] The semiconductor substrates (e.g., wafers) described herein are typically constructed from Group III-V compounds such as silicon, silicon germanium, and GaAs, or any combination thereof. The semiconductor substrates may further include exposed integrated circuit structures such as interconnection features (e.g., metal wires and dielectric materials). Metals and metal alloys used in the interconnection features include, but are not limited to, aluminum, aluminum alloyed with copper, copper, titanium, tantalum, cobalt, silicon, titanium nitride, tantalum nitride, and tungsten. The semiconductor substrates may also include layers of interlayer dielectrics, polysilicon, silicon oxide, silicon nitride, silicon germanium, silicon carbide, titanium oxide, and carbon-doped silicon oxide.

[0038] The semiconductor substrate may be brought into contact with the etching composition by any suitable method, for example, by placing the etching composition in a bath and immersing and / or submerging the semiconductor substrate in the etching composition, by spraying the etching composition onto the semiconductor substrate, by flowing the etching composition onto the semiconductor substrate, or by any combination thereof.

[0039] The etching compositions of this disclosure can be effectively used at temperatures of at least about 20°C to about 60°C. Since the etching rate of HfOx increases with temperature within this range, processes at higher temperatures can be performed in shorter times. Conversely, lower etching temperatures typically require longer etching times.

[0040] Etching time can vary over a wide range depending on the specific etching method, thickness, and temperature used. For single-wafer etching processes, a suitable time range is, for example, about 10 minutes or less (e.g., about 1 minute to 7 minutes, about 1 minute to 5 minutes, or about 0.5 minutes to 4 minutes). For immersion batch processes, etching time may range from about 30 seconds to about 60 minutes (e.g., about 1 minute to 60 minutes, about 10 minutes to 60 minutes, about 20 minutes to 60 minutes, or about 30 minutes to 60 minutes).

[0041] Mechanical stirring means may be used to further enhance the etching ability of the etching composition of this disclosure. Examples of suitable stirring means include circulation of the etching composition on the substrate, flow or spraying of the etching composition on the substrate, and ultrasonic stirring or megasonic stirring during the etching process. The orientation of the semiconductor substrate relative to the ground may be at any angle. Horizontal or vertical orientation is preferred.

[0042] Following etching, the semiconductor substrate may be rinsed with a suitable rinsing solvent for about 5 seconds to about 5 minutes, with or without agitation. Multiple rinsing steps using different rinsing solvents may be used. Examples of suitable rinsing solvents include, but are not limited to, deionized (DI) water, methanol, ethanol, isopropyl alcohol, N-methylpyrrolidinone, γ-butyrolactone, dimethyl sulfoxide, ethyl lactate, and propylene glycol monomethyl ether acetate. Alternatively, or in addition, an aqueous rinsing solution with pH > 8 (such as a dilute aqueous solution of ammonium hydroxide) may be used. The rinsing solvent may be applied using means similar to those used when applying the etching composition described herein. The etching composition may be removed from the semiconductor substrate before the start of the rinsing step, or it may still be in contact with the semiconductor substrate at the start of the rinsing step. In some embodiments, the temperature used in the rinsing step is 16°C to 27°C.

[0043] Optionally, the semiconductor substrate is dried after the rinsing step. Any suitable drying method known in the art may be used. Examples of suitable drying methods include spin drying, circulating a drying gas over the entire semiconductor substrate, heating the semiconductor substrate using a heating means such as a hot plate or infrared lamp, Marangoni drying, Rotagoni drying, IPA drying, and any combination thereof. The drying time varies depending on the specific method used, but is typically on the order of 30 seconds to several minutes.

[0044] In some embodiments, the etching method described herein further includes forming a semiconductor device (e.g., an integrated circuit device such as a semiconductor chip) from a semiconductor substrate obtained by the above method.

[0045] While the present invention has been described in detail with reference to its specific embodiments, it will be understood that any modifications and changes are within the spirit and scope of those described in the specification and claims.

[0046] This disclosure is illustrated in more detail by the following examples, which are illustrative and should not be construed as limiting the scope of this disclosure. [Examples]

[0047] General Procedure 1 Blend of ingredients A sample of the etching composition was prepared by adding the remaining components of the formulation to a calculated amount of solvent while stirring.

[0048] General Procedure 2 Materials and methods For evaluation purposes, commercially available 300 mm diameter unpatterned wafers, diced into 1.5 cm × 5.0 cm test pieces, were used to measure the blanket film etching rate against the film. The main blanket film materials used in the test included 1) an HfOx film with a thickness of approximately 200 Å deposited on a silicon substrate, and 2) an SiOx film with a thickness of approximately 1000 Å deposited on a silicon substrate.

[0049] The thickness of blanket film specimens was measured before and after treatment to determine the blanket film etching rate. For HfOx and SiOx blanket films, the film thickness was measured at three points on each specimen before and after treatment using ellipsometry with a Woollam VASE.

[0050] General Procedure 3 Etching evaluation by beaker test All blanket film etching tests were performed in a 500 ml PTFE beaker containing 200 g of sample solution, with continuous stirring at 250 rpm. The beaker was placed on a hot stirrer and set to the desired temperature. All blanket specimens with a blanket film exposed on one side to the sample solution were diced to a specimen size of 1.5 cm × 2.0 cm by diamond scribing for beaker-scale testing. Each specimen was held in place using a 4-inch long locking plastic tweezers clip. The specimen, held at one end by the locking tweezers clip, was suspended in the 500 ml PTFE beaker and immersed in 200 g of the test solution, which was continuously stirred at 250 rpm at 23°C. The specimen was kept stationary in the stirred solution for the processing time (1 minute, 3 minutes, or 10 minutes).

[0051] After the processing time had elapsed, the test specimens were immediately removed from the 500 ml PTFE beaker and rinsed. Specifically, the test specimens were immersed in 200 ml of isopropyl alcohol (IPA) for 15 seconds with gentle stirring, and then immersed in 200 ml of ultra-high purity deionized (DI) water for 20 seconds with gentle stirring. After the final rinsing step, all test specimens were subjected to a filtered nitrogen gas blowing step using a handheld nitrogen gas blower to forcibly remove any trace amounts of IPA, and a final dry sample for test measurement was obtained.

[0052] Example 1 Formulations 1-34 (FE-1-FE-34) were prepared according to general procedure 1 and evaluated according to general procedures 2 and 3. The formulations for FE-1-FE-34 are summarized in Table 2, and the test results are summarized in Table 3. In Table 3, the HfO2 etching rate was measured after immersing the test specimen in the formulation for 1 minute or 3 minutes at 23°C, and the SiO2 etching rate was measured after immersing the test specimen in the formulation for 10 minutes at 23°C. [Table 2] MMB = 3-methoxy-3-methyl-1-butanol, EGBE = Ethylene glycol monobutyl ether, DEGBE = Diethylene glycol monobutyl ether, PC = Propylene Carbonate MEK = Methyl ethyl ketone [Table 3] RT = room temperature, ER = etching rate FCVD SiO2 = SiO2 produced by flowable chemical vapor deposition. PEALD SiO2 = SiO2 fabricated by plasma-enhanced atomic layer deposition.

[0053] In general, etching compositions are desirable to have an HfOx etching rate of approximately 3 Å / min or higher, an SiOx etching rate of approximately 5 Å / min or lower, and an HfOx / SiOx etching rate selectivity of approximately 1 or higher. As shown in Table 3, numerous test formulations exhibited the above characteristics.

[0054] While the present invention has been described in detail with reference to its specific embodiments, it will be understood that any modifications and changes are within the spirit and scope of those described in the specification and claims.

Claims

1. A first acid containing a fluorine-containing inorganic acid or a salt thereof, Unlike the aforementioned first acid, the second acid comprises at least one acid having a pKa of about 3 or less, At least one organic solvent having a ClogP of approximately -0.3 to approximately 1.6, Water and, An etching composition containing the following:

2. The above-mentioned at least one first acid or salt thereof is HF, NH ４ F, NH ４ F・HF, TMAF, H ２ SiF ６ HPF ６ , or HBF ４ The composition according to claim 1, comprising:

3. The composition according to claim 1 or claim 2, wherein the amount of at least one first acid or salt thereof is about 0.1% to about 5% by weight relative to the composition.

4. The composition according to any one of claims 1 to 3, wherein the at least one second acid comprises hydrochloric acid, hydrobromic acid, nitric acid, phosphoric acid, sulfuric acid, or sulfonic acid.

5. The composition according to any one of claims 1 to 4, wherein the amount of at least one second acid is about 0.01% by weight to about 1% by weight relative to the composition.

6. The composition according to any one of claims 1 to 5, wherein the at least one organic solvent has about 0.2 to about 0.8 ClgP.

7. The composition according to any one of claims 1 to 5, wherein the at least one organic solvent comprises ethanol, isopropanol, tetrahydrofuran, ethylene glycol monobutyl ether, 3-methoxy-3-methyl-1-butanol, diethylene glycol monobutyl ether, 4-methyl-2-pentanol, or cyclohexanone.

8. The composition according to any one of claims 1 to 7, wherein the amount of at least one organic solvent is about 80% to about 99% by weight relative to the composition.

9. The composition according to any one of claims 1 to 8, wherein the amount of water is about 0.01% by weight to about 10% by weight relative to the composition.

10. A composition according to any one of claims 1 to 9, having a pH of approximately 0 to approximately 2.

11. A composition according to any one of claims 1 to 10, which is substantially free of oxidizing agents, complexing agents, surfactants, or amines.

12. The composition according to any one of claims 1 to 11, comprising the at least one first acid, the at least one second acid, the at least one organic solvent, and water.

13. A first acid containing a fluorine-containing inorganic acid or a salt thereof, At least one organic solvent having a ClogP of approximately -0.3 to approximately 1.6, Water and, An etching composition containing the following:

14. A method comprising contacting a semiconductor substrate supporting a hafnium oxide film with the composition described in any one of claims 1 to 13 to substantially remove the hafnium oxide film.

15. The method according to claim 14, wherein a pattern is formed on the surface of the semiconductor substrate, and the hafnium oxide film is part of the pattern.

16. The method according to claim 14 or claim 15, wherein silicon dioxide is not substantially removed.

17. An article which is a semiconductor device formed by the method described in any one of claims 14 to 16.

18. The article according to claim 17, wherein the semiconductor device is an integrated circuit.

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