Etching Composition

Abstract

The present disclosure is directed to etching compositions that are useful, for example, for selectively removing silicon from a semiconductor substrate as an intermediate step in a multi-step semiconductor manufacturing process.

Description

[Technical field]

[0001] Technical Field The present disclosure relates to etching compositions and methods of using the etching compositions. In particular, the present disclosure relates to etching compositions that can selectively etch silicon in the presence of other exposed or underlying materials, such as metal conductors (e.g., copper), gate materials (e.g., SiGe), barrier materials, insulator materials (e.g., low-k dielectrics), etc. [Background technology]

[0002] The semiconductor industry is rapidly moving towards a reduction in size and increased density of electronic circuits and components in microelectronic devices, silicon chips, liquid crystal displays, MEMS (microelectromechanical systems), printed wiring boards, and the like. The integrated circuits therein are layered or stacked, with the thickness of the insulating layers between each circuit layer constantly decreasing, resulting in smaller and smaller feature sizes. As feature sizes are reduced, patterns become smaller and device performance parameters become more stringent and more critical. As a result, various problems that were previously tolerable are no longer tolerable or have become more critical issues due to the smaller feature sizes.

[0003] In the manufacture of advanced integrated circuits, both high and low k insulators and a wide array of barrier layer materials are used to minimize problems and optimize performance associated with higher densities.

[0004] Silicon (Si) can be utilized in the manufacture of semiconductor devices, liquid crystal displays, MEMS (microelectromechanical systems), printed wiring boards, and the like. For example, it can be used as a sacrificial material in the manufacture of multi-gate devices such as multi-gate field effect transistors (FETs) (e.g., gate-all-around FETs (GAA FETs)). In particular, an epi-stack (i.e., an epitaxially grown stack) can be formed from alternating layers of silicon (Si) and silicon germanium alloy (SiGe), where the Si layer is the sacrificial layer and the SiGe layer is the channel layer. The Si layer can then be removed by selective etching (e.g., by a wet etching method), which also forms unintended trenches in the bulk substrate due to the similarity of the materials that make up the sacrificial layer and the substrate. A SiGe layer can then be formed in the nanowire channel formed beyond the trench. A thin gate dielectric is then deposited around the SiGe nanowire channel and over the trench formed in the substrate. Metal is then deposited over the dielectric to form the metal gate electrode of the GAA MOSFET. Summary of the Invention

[0005] In the construction of semiconductor devices, silicon (Si) frequently needs to be etched. In various types of Si applications and device environments, other layers are contacted or otherwise exposed at the same time that this material is etched. Highly selective etching of Si in the presence of these other materials (e.g., metal conductors, dielectrics, channel materials, gate materials, and hardmasks) is usually necessary for device yield and long life.

[0006] The present disclosure relates to compositions and methods for selective etching of Si relative to hardmask layers, gate materials (e.g., SiGe, SiN, or SiOx) and / or low-k dielectric layers (e.g., SiN, SiOx, carbon-doped oxide, or SiCO) present in semiconductor devices. More particularly, the present disclosure relates to compositions and methods for selective etching of Si relative to SiOx and / or SiN.

[0007] In one aspect, the disclosure features an etching composition that includes one or more quaternary ammonium hydroxides or salts thereof, one or more oxidizing agents, one or more polyamines, and water, the composition having a pH of about 13 or greater.

[0008] In another aspect, the disclosure features a method that includes contacting a semiconductor substrate supporting a Si-containing feature with an etching composition described herein to substantially remove the Si-containing feature.

[0009] In yet another aspect, the disclosure features an article formed by the above method, the article being a semiconductor device (eg, an integrated circuit). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] As defined herein, unless otherwise specified, all percentages expressed are to be understood as weight percent of the total weight of the composition. Unless otherwise specified, ambient temperature is defined to be about 16 to about 27 degrees Celsius (°C). As used herein, the terms "layer" and "film" are used interchangeably.

[0011] In general, the present disclosure features an etching composition (e.g., an etching composition for selectively removing Si) that includes (e.g., comprises or consists of) one or more quaternary ammonium hydroxides or salts thereof, one or more oxidizing agents, one or more polyamines, and water. In some embodiments, the etching composition includes only these four components. In some embodiments, the Si to be removed is amorphous silicon or polysilicon (poly-Si), such as doped poly-Si (e.g., n-type poly-Si). The doped poly-Si can include a suitable dopant, such as phosphorus.

[0012] In some embodiments, the etching compositions of the present disclosure can include one or more (e.g., two, three, or four) quaternary ammonium hydroxides or salts thereof. The quaternary ammonium hydroxides or salts thereof described herein can be tetraalkylammonium hydroxides or salts thereof (e.g., fluoride, chloride, or bromide salts). In some embodiments, each alkyl group in the tetraalkylammonium hydroxide can be independently selected from C, which can be optionally substituted with OH or aryl (e.g., phenyl). 1 ~C 18 Examples of suitable tetraalkylammonium hydroxides or salts thereof include tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, benzyltrimethylammonium hydroxide (BTMAH), methyltriethylammonium hydroxide, ethyltrimethylammonium hydroxide (ETMAH), dimethyldiethylammonium hydroxide, 2-hydroxyethyltrimethylammonium hydroxide, tetraethanolammonium hydroxide, benzyltriethylammonium hydroxide, benzyltributylammonium hydroxide, hexadecyltrimethylammonium hydroxide, and salts thereof.

[0013] In some embodiments, the one or more quaternary ammonium hydroxides or salts thereof are present in an amount of 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 2 wt% or more, about 3 wt% or more, about 4 wt% or more, or about 5 wt% or more) to about 20 wt% or less (e.g., about 18 wt% or less, about 16 wt% or less, about 15 wt% or less, about 14 wt% or less, about 12 wt% or less, about 10 wt% or less, about 8 wt% or less, about 7 wt% or less, about 6 wt% or less, about 5 wt% or less, about 4 wt% or less, about 2 wt% or less, or about 1 wt% or less) of the etching composition of the present disclosure. Without wishing to be bound by theory, it is believed that the quaternary ammonium hydroxides or salts thereof can facilitate and enhance the removal of Si on the semiconductor substrate during the etching process.

[0014] The etching compositions of the present disclosure can include one or more (e.g., two, three, or four) oxidizing agents. Examples of suitable oxidizing agents include periodic acid, perchloric acid, and hydrogen peroxide.

[0015] In some embodiments, the at least one oxidizing agent can be about 0.01 wt% or more (e.g., about 0.02 wt% or more, about 0.05 wt% or more, about 0.08 wt% or more, about 0.1 wt% or more, about 0.2 wt% or more, about 0.3 wt% or more, about 0.5 wt% or more, about 1 wt% or more, about 2 wt% or more, or about 3 wt% or more) to about 5 wt% or less (e.g., about 4.5 wt% or less, about 4 wt% or less, about 3.5 wt% or less, about 3 wt% or less, about 2.5 wt% or less, about 2 wt% or less, about 1.5 wt% or less, about 1 wt% or less, about 0.9 wt% or less, or about 0.5 wt% or less) of the etching composition of the present disclosure. Without wishing to be bound by theory, it is believed that the oxidizing agent can facilitate and enhance the removal of Si (e.g., poly-Si or doped poly-Si) on a semiconductor substrate (e.g., in a high aspect vial).

[0016] In general, the etching compositions of the present disclosure can include one or more (e.g., two, three, or four) polyamines. In some embodiments, the polyamines can include diamines (e.g., diamines having no functional groups (e.g., hydroxyl) other than amino groups), triamines (e.g., triamines having no functional groups (e.g., hydroxyl) other than amino groups), or alkanolamines (e.g., alkanolamines including at least two amino groups).

[0017] As used herein, the term "alkanolamine" refers to a compound that contains one or more (e.g., two, three, or four) amino groups and one or more (e.g., two, three, or four) hydroxyl groups. In some embodiments, the alkanolamine has the formula (I): OR 3 -RN(R 1 R 2 ) (I), wherein R is C 1 ~C 6 is a straight or branched chain alkylene; R 1 , R 2 , and R 3 each independently represents H, C 3 ~C 6 Cycloalkyl, or OH or NH 2 C optionally substituted with 1 ~C 6 An example of a suitable alkanolamine is N-(3-aminopropyl)diethanolamine.

[0018] In some embodiments, the polyamine has formula (I): N(R 3 R 4 )-RN(R 1 R 2 ) (I) In the formula (I), R is C 1 ~C 6 is a straight or branched chain alkylene; R 1 , R 2 , R 3 , and R 4 each independently represents H, C3 ~C 6 Cycloalkyl, or OH or N(R) 2 C optionally substituted with 1 ~C 6 alkyl, and each R is independently C 1 ~C 6 An example of a suitable triamine is pentamethyldiethylenetriamine.

[0019] In some embodiments, the one or more polyamines can be about 0.001 wt.% or more (e.g., about 0.002 wt.% or more, about 0.005 wt.% or more, about 0.01 wt.% or more, about 0.02 wt.% or more, about 0.04 wt.% or more, about 0.05 wt.% or more, about 0.06 wt.% or more, about 0.08 wt.% or more, about 0.1 wt.% or more, about 0.2 wt.% or more, or about 0.5 wt.% or more) to about 1 wt.% or less (e.g., about 0.8 wt.% or less, about 0.6 wt.% or less, about 0.5 wt.% or less, about 0.4 wt.% or less, about 0.2 wt.% or less, about 0.1 wt.% or less, about 0.08 wt.% or less, about 0.06 wt.% or less, or about 0.05 wt.% or less) of the etching composition of the present disclosure. Without wishing to be bound by theory, it is believed that the polyamines can reduce or minimize the corrosion or removal of SiN and / or SiOx on semiconductor substrates.

[0020] In general, the etching compositions of the present disclosure can include water as a solvent, in some embodiments, the water can be demineralized and ultrapure water, free of organic contaminants, and / or have a minimum resistivity of about 4 to about 17 megaohms or at least about 17 megaohms. In some embodiments, the water is in an amount of about 70% or more by weight (e.g., about 75% or more by weight, about 80% or more by weight, about 82% or more by weight, about 84% or more by weight, about 85% or more by weight, about 86% or more by weight, about 88% or more by weight, about 90% or more by weight, about 91% or more by weight, or about 92% or more by weight) to about 99% or less by weight (e.g., about 98% or less by weight, about 97% or less by weight, about 96% or less by weight, about 95% or less by weight, about 94% or less by weight, about 93% or less by weight, about 92% or less by weight, about 91% or less by weight, about 90% or less by weight, about 85% or less by weight, or about 80% or less by weight) of the etching composition. Without wishing to be bound by theory, it is believed that if the amount of water is greater than 99% by weight of the composition, it will adversely affect the Si etch rate and reduce its removal during the etching process. On the other hand, without wishing to be bound by theory, it is believed that the etching compositions of the present disclosure should contain a certain level of water (e.g., at least about 70% by weight) to avoid degrading etching performance.

[0021] In some embodiments, the etching compositions of the present disclosure may optionally include one or more (e.g., two, three, or four) organic solvents. In some embodiments, the organic solvent may be a water-soluble organic solvent. As defined herein, a "water-soluble" substance (e.g., a water-soluble organic solvent) refers to a substance that has a solubility of at least 1% by weight in water at 25°C. In some embodiments, the organic solvent may be selected from the group consisting of water-soluble alcohols (e.g., glycols such as alkanediols or alkylene glycols), water-soluble ketones, water-soluble esters, and water-soluble ethers (e.g., glycol ethers). Examples of suitable organic solvents include glycerol, propylene glycol, hexylene glycol, 1,3-propanediol, ethylene glycol butyl ether, 3-methoxy-3-methyl-1-butanol, acetone, cyclohexanone, ethyl acetate, and propylene glycol monoethyl ether acetate.

[0022] In some embodiments, the one or more organic solvents can be about 5% or more (e.g., about 10% or more, about 15% or more, about 20% or more, about 25% or more, about 30% or more, about 35% or more, or about 40% or more) to about 75% or less (e.g., about 70% or less, about 65% or less, about 60% or less, about 55% or less, about 50% or less, about 45% or less, or about 40% or less) by weight of the etching composition. In some embodiments, the etching compositions of the present disclosure can be substantially free of organic solvents.

[0023] In some embodiments, the etching compositions of the present disclosure can have a pH of about 13 or more (e.g., about 13.1 or more, about 13.2 or more, about 13.3 or more, about 13.4 or more, or about 13.5 or more) and / or about 14 or less (e.g., about 13.9 or less, about 13.8 or less, about 13.7 or less, about 13.6 or less, or about 13.5 or less). Without wishing to be bound by theory, it is believed that etching compositions having a pH less than 13 do not have sufficient Si removal rates and / or sufficient bath loading capacity.

[0024] In some embodiments, the etching compositions of the present disclosure can optionally include one or more (e.g., two, three, or four) pH adjusters (e.g., acids or bases) to control the pH to about 13 to about 14. When the concentrations of other components (e.g., the quaternary ammonium hydroxide and the polyamine) are varied in various formulations, the amount of the pH adjuster can be varied accordingly. In some embodiments, the pH adjuster can 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) of the etching composition. In some embodiments, the etching compositions of the present disclosure can be substantially free of pH adjusters.

[0025] In some embodiments, the pH adjuster is metal ion-free (except for trace amounts of 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, but are not limited to, monocarboxylic acids, dicarboxylic acids, tricarboxylic acids, monocarboxylic alpha-hydroxy acids and beta-hydroxy acids, dicarboxylic alpha-hydroxy acids or beta-hydroxy acids, or tricarboxylic alpha-hydroxy acids and beta-hydroxy acids. 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.

[0026] 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.

[0027] In some embodiments, the etching compositions of the present disclosure may include optional additives such as pH adjusters, rust inhibitors, surfactants, additional organic solvents, biocides, and antifoaming agents. Examples of certain suitable additives include alcohols (e.g., polyvinyl alcohol and sugar alcohols), organic acids (e.g., iminodiacetic acid, malonic acid, oxalic acid, succinic acid, and malic acid), and inorganic acids (e.g., boric acid). 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 capped acetylene diol ethoxylates (such as those described in U.S. Pat. No. 6,717,019, which is incorporated herein by reference). Examples of suitable surfactants may be cationic, anionic, nonionic, and amphoteric surfactants.

[0028] In general, the etching compositions of the present disclosure can have a relatively high Si / dielectric (e.g., SiN, SiOx, or SiCO) removal rate selectivity (i.e., the ratio of Si removal rate higher than the dielectric removal rate). In some embodiments, the etching compositions can have a Si / dielectric removal rate selectivity of about 10 or more (e.g., about 20 or more, about 40 or more, about 50 or more, about 60 or more, about 80 or more, about 100 or more, about 150 or more, about 200 or more, about 250 or more, about 300 or more, about 350 or more, about 400 or more, about 450 or more, or about 500 or more) and / or about 5000 or less (e.g., about 4000 or less, about 3000 or less, about 2000 or less, or about 1000 or less).

[0029] In some embodiments, the etching compositions of the present disclosure may be substantially free of any one or combination of additional components, such as organic solvents, 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), antifoaming agents, fluorine-containing compounds (e.g., fluoride compounds or fluorinated compounds (e.g., fluorinated polymers / surfactants, etc.)), silicon-containing compounds such as silanes (e.g., alkoxysilanes), nitrogen-containing compounds (e.g., amino acids, amines, imines (e.g., 1,8-diazabicyclo[5.4.0]-7-undecene (DBU) and 1,5-diazabicyclo[4.3.0]non-5-ene (DBN)), amides, or imides). abrasives (e.g., ceria abrasives, nonionic abrasives, surface modified abrasives, negatively / positively charged abrasives, or ceramic abrasive composites), plasticizers, oxidizers (e.g., peroxides such as hydrogen peroxide and periodic acid), rust inhibitors (e.g., azole or non-azole rust inhibitors), electrolytes (e.g., polyelectrolytes), silicates, cyclic compounds (e.g., azoles (diazoles, triazoles, or tetrazoles, etc.), triazines, and substituted or unsubstituted naphthalene water, or substituted or unsubstituted biphenyl ethers, etc. The etching composition may be selected from the group consisting of cyclic compounds containing at least two rings, chelating agents, buffering agents, organic acids (e.g., carboxylic acids such as hydroxycarboxylic acids, polycarboxylic acids, and sulfonic acids) and inorganic acids (e.g., sulfuric acid, sulfurous acid, nitrous acid, 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 salts other than quaternary ammonium salts. As used herein, a component that is "substantially free" of an etching composition refers to a component that is not intentionally added to the etching composition. In some embodiments, the etching compositions described herein may have 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) of one or more of the above components that are substantially free of the etching composition. In some embodiments, the etching compositions described herein may be completely free of one or more of the above components.

[0030] The etching compositions of the present disclosure may be prepared by simply mixing the components together, or may be prepared by combining two or more compositions in a kit, each containing certain components of the etching compositions described herein.

[0031] In some embodiments, the present disclosure features a method of etching a semiconductor substrate including at least one Si-containing feature. The method can include contacting the semiconductor substrate including the at least one Si-containing feature with an etching composition of the present disclosure to substantially remove the Si-containing feature. In some embodiments, the semiconductor substrate can include a pattern on a surface, and the Si-containing feature thin film is part of the pattern. In some embodiments, the method can further include rinsing the semiconductor substrate with a rinsing solvent after the contacting step and / or drying the semiconductor substrate after the rinsing step.

[0032] In some embodiments, the method does not substantially remove metal conductors (e.g., Cu) or dielectrics (e.g., SiN, SiOx, or SiCO) in the semiconductor substrate. For example, the method does not remove more than about 5% by weight (e.g., more than about 3% by weight or more than about 1% by weight) of the metal conductors or dielectrics in the semiconductor substrate.

[0033] In some embodiments, the etching method comprises: (A) providing a semiconductor substrate including Si-containing features (e.g., in a pattern); (B) contacting the semiconductor substrate with an etching composition described herein; (C) rinsing the semiconductor substrate with one or more suitable rinsing solvents; (D) optionally drying the semiconductor substrate (e.g., by any suitable means that removes rinsing solvent and does not damage the integrity of the semiconductor substrate); Includes.

[0034] Semiconductor substrates etched in this manner may contain organic and organometallic residues, and a range of metal oxides, some or all of which may be removed during the etching process.

[0035] The semiconductor substrate (e.g., wafer) described herein is typically composed of silicon, silicon germanium, III-V compounds such as GaAs, or any combination thereof. The semiconductor substrate may additionally include exposed integrated circuit structures such as interconnect features (e.g., metal lines and dielectrics). Metals and metal alloys used for interconnect features include, but are not limited to, aluminum, aluminum alloys with copper, copper, titanium, tantalum, cobalt, silicon, titanium nitride, tantalum nitride, and tungsten. The semiconductor substrate may also include layers of interlayer dielectrics, polysilicon, silicon oxide, silicon nitride, silicon germanium, silicon carbide, titanium oxide, and carbon-doped silicon oxide.

[0036] The semiconductor substrate may be contacted with the etching composition by any suitable method, such as by placing the etching composition in a bath and dipping 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 any combination thereof.

[0037] The etching compositions of the present disclosure can be effectively used at temperatures up to about 85° C. (e.g., about 50° C. to about 85° C., about 60° C. to about 80° C., or about 65° C. to about 75° C.). The etch rate of Si increases with temperature within this range, so processes at higher temperatures can be carried out in shorter times. Conversely, lower etching temperatures typically require longer times.

[0038] Etching times can vary over a wide range depending on the particular etching method, thickness, and temperature used. For etching in an immersion batch process, a suitable time range is, for example, about 10 minutes or less (e.g., about 1 minute to about 7 minutes, about 1 minute to about 5 minutes, or about 2 minutes to about 4 minutes). Etching times for single wafer processes can range from about 30 seconds to about 60 minutes (e.g., about 10 minutes to about 60 minutes, about 20 minutes to about 60 minutes, or about 30 minutes to about 60 minutes).

[0039] To further enhance the etching ability of the etching composition of the present disclosure, mechanical agitation means can be used. Examples of suitable agitation means include circulation of the etching composition over the substrate, flow or spraying of the etching composition over the substrate, and ultrasonic or megasonic agitation during the etching process. The orientation of the semiconductor substrate with respect to the ground can be at any angle. Horizontal or vertical orientation is preferred.

[0040] After etching, the semiconductor substrate can be rinsed with a suitable rinsing solvent for about 5 seconds to about 5 minutes or less with or without agitation. A multi-step rinsing step using different rinsing solvents can be used. Examples of suitable rinsing solvents include, but are not limited to, demineralized (DI) water, methanol, ethanol, isopropyl alcohol, N-methylpyrrolidinone, γ-butyrolactone, dimethylsulfoxide, ethyl lactate, and propylene glycol monomethyl ether acetate. Alternatively, or in addition, an aqueous rinse with a pH>8 (such as a dilute aqueous solution of ammonium hydroxide) can be used. Rinse solvents can be applied using similar means as those used in applying the etching compositions described herein. The etching composition may be removed from the semiconductor substrate before the start of the rinsing step or 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 between 16°C and 27°C.

[0041] Optionally, the semiconductor substrate is dried after the rinsing step. Any suitable drying means known in the art can be used. Examples of suitable drying means include spin drying, flowing a drying gas over the semiconductor substrate, or heating the semiconductor substrate using a heating means such as a hot plate or an infrared lamp, Marangoni drying, Rotagoni drying, IPA drying, and any combination thereof. Drying time depends on the particular method used, but is usually on the order of 30 seconds to a few minutes or less.

[0042] In some embodiments, the etching methods described herein further include forming a semiconductor device (e.g., an integrated circuit device such as a semiconductor chip) from the semiconductor substrate obtained by the method.

[0043] Although the invention has been described in detail with reference to specific embodiments thereof, it will be understood that modifications and variations are within the spirit and scope of what is described in the specification and claims.

[0044] The present disclosure will be illustrated in more detail with reference to the following examples, which are for illustrative purposes and should not be construed as limiting the scope of the disclosure. EXAMPLES

[0045] Basic Step 1 Formulation Combination Samples of the etching composition were prepared by adding the calculated amount of solvent to the remaining components of the formulation with stirring.

[0046] Basic Step 2 Materials and Methods Thin blanket film etch rate measurements were performed using commercially available unpatterned 300 mm diameter wafers that were diced into 0.5" x 1.0" test coupons for evaluation. The primary blanket film materials used for testing included: 1) an approximately 3000 Å thick polysilicon (poly-Si) film deposited on a silicon substrate; 2) an approximately 140 Å thick SiN film deposited on a silicon substrate; and 3) an approximately 1200 Å thick SiOx film deposited on a silicon substrate.

[0047] Blanket film test coupons were measured for pre- and post-treatment thickness to determine blanket film etch rates. For poly-Si, SiN, and SiOx blanket films, thin film thickness was measured pre- and post-treatment by ellipsometry using a Woollam VASE.

[0048] Basic Step 3 Etching evaluation using the beaker test Full blanket film etch testing was performed at 70°C to 75°C in a 600 mL glass beaker containing 200 g of sample solution with continuous stirring at 250 rpm, with a Parafilm® cover in place at all times to minimize evaporative loss. Full blanket test coupons with blanket films exposed on one side to the sample solution were diced with a diamond scribe into 0.5" x 1.0" square test coupon size for beaker-scale testing. Each individual test coupon was held in position using a single 4" long plastic locking tweezer clip. The test coupon, held by one edge with the locking tweezer clip, was suspended in a 600 mL high density polyethylene (HDPE) beaker and immersed in 200 g of test solution while the solution was continuously stirred at 250 rpm at 75°C. Immediately after each sample coupon was placed in the stirred solution, the top of the 600 mL high density polyethylene (HDPE) beaker was covered with Parafilm®. The test coupons were held stationary in the stirred solution until the treatment time (0.5 minutes or 60 minutes) had elapsed.

[0049] After the treatment time in the test solutions had elapsed, the sample coupons were immediately removed from the 600 mL high density polyethylene (HDPE) beaker and rinsed. Specifically, the coupons were immersed in a 300 mL volume of ultrapure demineralized (DI) water for 15 seconds with gentle agitation, then immersed in 300 mL of isopropyl alcohol (IPA) for 15 seconds with gentle agitation, and given a final rinse by immersing in 300 mL of IPA for 15 seconds with gentle agitation. After the final IPA rinse step, all test coupons were subjected to a filtered nitrogen gas blow-off step using a handheld nitrogen gas blower to forcefully remove all traces of IPA.

[0050] Example 1 Formulation Examples 1-12 (FE-1-FE-12) were prepared according to General Procedure 1 and evaluated according to General Procedures 2 and 3. Formulations containing polyamines (i.e., FE-1-FE-8) and their test results are summarized in Table 1. Poly-Si etch rates were measured after immersion of test coupons in the formulations for 0.5 minutes at 75° C. SiN and SiOx etch rates were measured after immersion of test coupons in the formulations for 60 minutes at 75° C.

[0051] [Table 1] APDA = N-(3-aminopropyl)diethanolamine PMDTA = pentamethyldiethylenetriamine BTMAH = benzyltrimethylammonium hydroxide ER = etch rate

[0052] The formulations without polyamines (ie, FE-9 through FE-12) and the test results are summarized in Table 2.

[0053] [Table 2]

[0054] As shown in Tables 1 and 2, FE-1 through FE-8 (all of which contained polyamine) exhibited lower SiN and / or SiOx etch rates compared to FE-9 through FE-12 (which did not contain polyamine).

[0055] Related Applications This application claims priority to U.S. Provisional Patent Application No. 63 / 318,498, filed March 10, 2022, the contents of which are incorporated by reference in their entirety herein.

Claims

1. one or more quaternary ammonium hydroxides or salts thereof; one or more oxidizing agents; one or more polyamines; Water, An etching composition comprising: The composition has a pH of about 13 or greater. composition.

2. 2. The composition of claim 1, wherein the one or more quaternary ammonium hydroxides or salts thereof comprise a tetraalkylammonium hydroxide or salt thereof.

3. 2. The composition of claim 1, wherein the one or more quaternary ammonium hydroxides or salts thereof comprise tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, benzyltrimethylammonium hydroxide, methyltriethylammonium hydroxide, ethyltrimethylammonium hydroxide, dimethyldiethylammonium hydroxide, 2-hydroxyethyltrimethylammonium hydroxide, tetraethanolammonium hydroxide, benzyltriethylammonium hydroxide, benzyltributylammonium hydroxide, hexadecyltrimethylammonium hydroxide, or salts thereof.

4. The composition of claim 1, wherein the one or more quaternary ammonium hydroxides or salts thereof are in an amount of about 0.1% to about 20% by weight of the composition.

5. The composition of claim 1 , wherein the one or more oxidizing agents comprise periodic acid, perchloric acid, or hydrogen peroxide.

6. The composition of claim 1, wherein the one or more oxidizing agents are in an amount of about 0.01% to about 5% by weight of the composition.

7. 2. The composition of claim 1, wherein the one or more polyamines comprise a diamine, a triamine, or an alkanolamine containing at least two amino groups.

8. The composition of claim 1, wherein the one or more polyamines comprise N-(3-aminopropyl)diethanolamine or pentamethyldiethylenetriamine.

9. The composition of claim 1 , wherein the one or more polyamines are in an amount of from about 0.001% to about 1% by weight of the composition.

10. The composition of claim 1 , wherein the water is in an amount of from about 70% to about 99% by weight of the composition.

11. The composition of claim 1 , wherein the composition has a pH of about 14 or less.

12. 10. The composition of claim 1, wherein the composition is substantially free of organic solvents, salts other than quaternary ammonium salts, and rust inhibitors.

13. 2. The composition of claim 1, wherein the composition consists solely of the one or more quaternary ammonium hydroxides or salts thereof, one or more oxidizing agents, one or more polyamines, and water.

14. 13. A method comprising contacting a semiconductor substrate supporting a Si-containing feature with the composition of claim 1 to substantially remove the Si-containing feature.

15. 15. The method of claim 14, wherein a pattern is formed on a surface of the semiconductor substrate, and the Si-containing feature is part of the pattern.

16. 15. The method of claim 14, wherein the method does not substantially remove SiN or SiOx.

17. 15. An article formed by the method of claim 14, wherein the article is a semiconductor device.

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

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