Etching compositions

Abstract

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

Description

[Technical Field]

[0001] Cross-reference to related applications

[0002] This application claims priority to U.S. Provisional Application No. 63 / 314,624, filed February 28, 2022, and U.S. Provisional Application No. 63 / 320,272, filed March 16, 2022, the contents of which are incorporated herein by reference in their entirety. This disclosure field

[0003] This disclosure relates to an etching composition and a method of using the etching composition. In particular, this disclosure relates to an etching composition that can selectively etch silicon in the presence of other exposed or underlying materials, such as metallic conductors (e.g., copper), gate materials (e.g., SiGe), barrier materials, and insulating materials (e.g., low-k dielectric materials). [Previous Technology]

[0004] Background of this disclosure

[0005] The semiconductor industry has been rapidly shrinking the size and increasing the density of electronic circuits and components in microelectronic devices, silicon wafers, liquid crystal displays, MEMS (microelectromechanical systems), printed circuit boards, etc. Integrated circuits are layered or stacked, with the thickness of the insulating layer between each circuit layer continuously decreasing, resulting in smaller and smaller topological dimensions. As the topological dimensions shrink, patterns become smaller, and device performance parameters become more compact and robust. Therefore, various problems that were previously tolerable are no longer tolerable or become more problematic due to the smaller topological dimensions.

[0006] In the production of advanced integrated circuits, high-k and low-k insulators and various barrier layer materials have been used to minimize problems related to higher density and optimize performance.

[0007] Silicon (Si) can be used in the manufacture of semiconductor devices, liquid crystal displays, MEMS (microelectromechanical systems), printed circuit boards, etc. For example, it can be used as a sacrificial material in the manufacturing process of multi-gate devices, such as multi-gate field-effect transistors (FETs) (e.g., gate-all-around FETs (GAA FETs)). In particular, an epitaxial stack (i.e., an epitaxial growth stack) can be formed from alternating layers of silicon (Si) and silicon-germanium alloy (SiGe), wherein 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 wet etching), and since the material constituting the sacrificial layer is similar to the substrate, the etching may unintentionally create trenches in the bulk substrate. Subsequently, the SiGe layer can be formed in nanowire channels suspended over the trenches. Then, a thin gate dielectric is disposed around the SiGe nanowire channels and in the recessed trenches of the substrate. Then, a metal is disposed on the dielectric to form the metal gate electrode of the GAA MOSFET. [Summary of the Invention]

[0008] Summary of this disclosure

[0009] In the construction of semiconductor devices, silicon (Si) etching is frequently required. In the various applications and device environments of Si, other layers may come into contact with or be exposed to it in other ways during the etching process. In the presence of these other materials (such as metallic conductors, dielectrics, channel materials, gate materials, and hard masks), highly selective Si etching is usually required to achieve device throughput and long service life.

[0010] This disclosure relates to a composition and method for selectively etching Si relative to a hard mask layer, a gate material (e.g., SiGe, SiN, polycrystalline Si, or SiOx), and / or a low-k dielectric layer (e.g., SiN, polycrystalline Si, SiOx, carbon-doped oxide, or SiCO) in a semiconductor device. More specifically, this disclosure relates to a composition and method for selectively etching Si relative to SiGe and / or SiN.

[0011] In one embodiment, the present disclosure is characterized by an etching composition comprising a) at least one quaternary ammonium hydroxide or a salt thereof; b) at least one alkanolamine; c) at least one SiGe corrosion inhibitor comprising 11-mercaptoundecylphosphonic acid, 8-mercaptooctanoic acid, 6-mercaptohexanoic acid, 12-mercaptododecanoic acid, 8-quinolineboronic acid, 8-aminequinoline, 8-quinolinecarboxylic acid, 8-quinolinethiol, 2,8-quinolinediol, 8-quinolineacetic acid, 8-quinolinesulfonic acid, 2-methyl-8-quinolineol, 5-hydroxyquinoline or 6-hydroxyquinoline mercapto-acid, substituted quinoline or a salt thereof; d) at least one polymeric naphthalenesulfonic acid; e) at least one organic solvent; and f) water.

[0012] In another embodiment, the present disclosure is characterized by an etching composition comprising a) at least one quaternary ammonium hydroxide or a salt thereof; b) at least one alkanolamine; c) at least one SiGe corrosion inhibitor comprising a mercapto acid, a substituted quinoline or a salt thereof; d) at least one polymeric naphthalenesulfonic acid; e) at least one organic solvent; and f) water.

[0013] In another embodiment, the present disclosure is characterized by a method comprising contacting a semiconductor substrate containing a Si film with an etch composition described herein to substantially remove the Si film.

[0014] In yet another aspect, the present disclosure is characterized by an article formed by the above method, wherein the article is a semiconductor device (e.g., an integrated circuit).

Implementation Method

[0015] Detailed Explanation of This Disclosure

[0016] Unless otherwise stated, all percentages defined herein shall be understood as percentages by weight of the total weight of the components. Unless otherwise stated, ambient temperature is defined as between about 16 and about 27 degrees Celsius (°C). The terms “layer” and “film” as used herein are used interchangeably.

[0017] Generally, the present disclosure is characterized by an etching composition (e.g., an etching composition for selectively removing Si) comprising a) at least one quaternary ammonium hydroxide or a salt thereof; b) at least one alkanolamine; c) at least one SiGe corrosion inhibitor; d) at least one polymeric naphthalene sulfonic acid; e) at least one organic solvent; and f) water.

[0018] In some embodiments, the etch composition disclosed herein may include at least one (e.g., two, three, or four) quaternary ammonium hydroxide or a salt thereof. The quaternary ammonium hydroxide or its salts described herein may be tetraalkylammonium hydroxide or its salts. In some embodiments, each alkyl group in the tetraalkylammonium hydroxide is independently a C1-C18 alkyl group optionally substituted with OH or an aryl group (e.g., phenyl). Suitable examples of tetraalkylammonium hydroxide or its salts include tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, benzyltrimethylammonium hydroxide, methyltriethylammonium hydroxide, ethyltrimethylammonium hydroxide (ETMAH), 2-hydroxyethyltrimethylammonium hydroxide, benzyltriethylammonium hydroxide, hexadecyltrimethylammonium hydroxide, or salts thereof.

[0019] In some embodiments, the amount of the at least one quaternary ammonium hydroxide or its salt thereof is at least about 0.1% by weight (e.g., at least about 0.2% by weight, at least about 0.4% by weight, at least about 0.5% by weight, at least about 0.6% by weight, at least about 0.8% by weight, at least about 1% by weight, at least about 2% by weight, at least about 3% by weight, at least about 4% by weight, or at least about 5% by weight) to at most about 10% by weight (e.g., at most about 9% by weight, at most about 8% by weight, at most about 7% by weight, at most about 6% by weight, at most about 5% by weight, at most about 4% by weight, at most about 3% by weight, at most about 2% by weight, at most about 1% by weight, or at most about 0.5% by weight) of the etch composition disclosed herein. It is not intended to be theoretically limited, but it is believed that the quaternary ammonium hydroxide or its salt thereof can promote and enhance the removal of Si from the semiconductor substrate during the etching process.

[0020] The etch composition disclosed herein may include at least one (e.g., two, three, or four) alkanolamine. The term "alkanolamine" as used herein refers to a compound comprising at least one (e.g., two, three, or four) amino group and at least one (e.g., two, three, or four) hydroxyl group. In some embodiments, the alkanolamine may be a compound having the formula (I): OR 3-RN(R 1R 2) (I), wherein R is a C 1-C 6 straight or branched alkyl or oxoalkyl group, and each of R 1, R 2, and R 3 is independently H, a C 3-C 6 cycloalkyl, or a C 1-C 6 alkyl group, optionally substituted with OH or NH 2. Suitable examples of alkanolamines include N-methylethanolamine (NMEA), monoethanolamine (MEA), diethanolamine, triethanolamine, triisopropanolamine, 2-(2-aminoethylamino)ethanol (also known as aminoethylethanolamine or AEEA), 2-(2-aminoethoxy)ethanol (AEE), N-ethylethanolamine, N,N-dimethylethanolamine, N,N-diethylethanolamine, N-methyldiethanolamine, N-ethyldiethanolamine, diisopropanolamine, or cyclohexylamine diethanolamine.

[0021] In some embodiments, the at least one alkanolamine may comprise at least about 0.01% by weight (e.g., at least about 0.05% by weight, at least about 0.1% by weight, at least about 0.5% by weight, at least about 1% by weight, at least about 2% by weight, at least about 3% by weight, at least about 4% by weight, or at least about 5% by weight) to at most about 10% by weight (e.g., at most about 9% by weight, at most about 8% by weight, at most about 7% by weight, at most about 6% by weight, at most about 5% by weight, at most about 4% by weight, at most about 3% by weight, at most about 2% by weight, or at most about 1% by weight) of the etch composition disclosed herein. Not wishing to be bound by theory, it is believed that the alkanolamine may reduce or minimize the removal of other exposed materials on the semiconductor substrate during the etching process of the Si layer.

[0022] Generally, the etching composition disclosed herein may include at least one (e.g., two, three, or four) SiGe corrosion inhibitor. In some embodiments, the SiGe corrosion inhibitor may include a salt of a mercapto-acid, a substituted quinoline, or the like. In some embodiments, the mercapto-acid may be a mercapto-phosphate or a mercapto-carboxylic acid. Suitable examples of mercapto-acids may include 11-mercaptoundecylphosphate, 8-mercaptooctanoic acid, 6-mercaptohexanoic acid, 11-mercaptoundecanoic acid, and 12-mercaptododecanoic acid. In some embodiments, the substituted quinoline includes quinolines substituted with OH, NH₂, COOH, SH, CH₂COOH, SO₃H, or borate groups. Suitable examples of substituted quinolines include 8-quinolineboronic acid, 8-aminoquinoline, 8-quinolinecarboxylic acid, 8-quinolinethiol, 2,8-quinolinediol, 8-quinolineacetic acid, 8-quinolinesulfonic acid, 2-methyl-8-quinolineol, 5-hydroxyquinoline, 6-hydroxyquinoline, and 8-hydroxyquinoline.

[0023] In some embodiments, the at least one SiGe etching inhibitor may comprise at least about 0.01% by weight (e.g., at least about 0.02% by weight, at least about 0.05% by weight, at least about 0.1% by weight, at least about 0.2% by weight, at least about 0.5% by weight, or at least about 1% by weight) to at most about 3% by weight (e.g., at most about 2.5% by weight, at most about 2% by weight, at most about 1.5% by weight, at most about 1% by weight, at most about 0.8% by weight, at most about 0.6% by weight, at most about 0.5% by weight, at most about 0.4% by weight, at most about 0.2% by weight, or at most about 0.1% by weight) of the etch composition disclosed herein. Without being bound by theory, it is believed that the SiGe etching inhibitor can reduce or minimize the etching or removal of SiGe on a semiconductor substrate.

[0024] In some embodiments, the etch composition disclosed herein may optionally include at least one (e.g., two, three, or four) polymeric naphthalene sulfonic acid (or poly(naphthalene sulfonic acid)), such as, as a surfactant or selective inhibitor (e.g., a SiN corrosion inhibitor). In some embodiments, the polymeric naphthalene sulfonic acid may be a sulfonic acid having the following chemical structure: where n is 3, 4, 5, or 6. Examples of commercially available polymeric naphthalene sulfonic acids include the Takesurf A-47 series products available from Takemoto Oil & Fat Co., Ltd.

[0025] In some embodiments, the at least one polymeric naphthalene sulfonic acid may account for at least about 0.01% by weight (e.g., at least about 0.02% by weight, at least about 0.05% by weight, at least about 0.1% by weight, at least about 0.2% by weight, at least about 0.5% by weight, or at least about 1% by weight) to at most about 3% by weight (e.g., at most about 2.5% by weight, at most about 2% by weight, at most about 1.5% by weight, at most about 1% by weight, at most about 0.8% by weight, at most about 0.6% by weight, at most about 0.5% by weight, at most about 0.4% by weight, at most about 0.2% by weight, or at most about 0.1% by weight) of the etching composition disclosed herein. Without being bound by theory, it is believed that when removing Si from a semiconductor substrate using the etching composition disclosed herein, the polymeric naphthalene sulfonic acid may selectively inhibit the removal of SiN, polycrystalline Si, and SiCO.

[0026] In some embodiments, the etch composition disclosed herein may include at least one (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) means a substance having a solubility of at least 1% in water at 25°C. In some embodiments, the organic solvent may be selected from the group consisting of: water-soluble alcohols (e.g., alkane diols or glycols, such as 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.

[0027] In some embodiments, the at least one organic solvent may account for at least about 5% by weight (e.g., at least about 10% by weight, at least about 15% by weight, at least about 20% by weight, at least about 25% by weight, at least about 30% by weight, at least about 35% by weight, or at least about 40% by weight) to at most about 75% by weight (e.g., at most about 70% by weight, at most about 65% by weight, at most about 60% by weight, at most about 55% by weight, at most about 50% by weight, at most about 45% by weight, or at most about 40% by weight) of the etched composition.

[0028] Generally, the etching composition disclosed herein may include water as a solvent. In some embodiments, the water may be deionized and ultrapure, free of organic contaminants, and have a minimum resistivity of about 4 to about 17 megohms or at least about 17 megohms. In some embodiments, the amount of water is at least about 25% by weight (e.g., at least about 30% by weight, at least about 35% by weight, at least about 40% by weight, at least about 45% by weight, at least about 50% by weight, at least about 55% by weight, or at least about 60% by weight) to at most about 95% by weight (e.g., at most about 90% by weight, at most about 85% by weight, at most about 80% by weight, at most about 75% by weight, at most about 70% by weight, at most about 65% by weight, at most about 60% by weight, at most about 55% by weight, at most about 50% by weight, at most about 45% by weight, or at most about 40% by weight). Without being bound by theory, it is believed that the etching composition disclosed herein should include a certain level of water (e.g., at least about 25% by weight) to keep all other components soluble and avoid degradation of etching performance.

[0029] In some embodiments, the etch composition disclosed herein may have a pH of at least about 4 (e.g., at least about 4.2, at least about 4.4, at least about 4.5, at least about 4.6, at least about 4.8, at least about 5, at least about 5.2, at least about 5.4, at least about 5.5, at least about 5.6, at least about 5.8, or at least about 6) and / or up to about 8 (e.g., up to about 7.8, up to about 7.6, up to about 7.5, up to about 7.4, up to about 7.2, up to about 7, up to about 6.8, up to about 6.6, up to about 6.5, up to about 6.4, up to about 6.2, or up to about 6). It is not intended to be theoretically constrained, but it is believed that etch compositions with a pH above 8 do not have sufficient Si selectivity relative to the gate material (e.g., SiGe) and / or low-k dielectric material (e.g., SiN). Furthermore, it is believed that etch compositions with a pH below 4 will decompose some components of the composition due to strong acidity.

[0030] Furthermore, in some embodiments, the etching composition disclosed herein may contain additives such as pH adjusters, corrosion inhibitors, surfactants, additional organic solvents, bactericides, and defoamers as optional components. Examples of 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 defoamers include polysiloxane defoamers (e.g., polydimethylsiloxane), polyethylene glycol methyl ether polymers, ethylene oxide / propylene oxide copolymers, and glycidyl ether-terminated alkyne diol ethoxylates (e.g., those described in U.S. Patent No. 6,717,019, which are incorporated herein by reference). Examples of suitable surfactants may be cationic, anionic, nonionic, or amphoteric surfactants.

[0031] Generally, the etch composition disclosed herein may have a relatively high Si / Ge etch selectivity (i.e., a high Si etch rate to SiGe etch rate ratio). In some embodiments, the etch composition may have a Si / SiGe etch selectivity of at least about 2 (e.g., at least about 3, at least about 4, at least about 5, at least about 6, at least about 7, at least about 8, at least about 9, at least about 10, at least about 15, at least about 20, at least about 30, at least about 40 or at least about 50) and / or up to about 500 (e.g., up to about 100).

[0032] In some embodiments, the etch composition disclosed herein may be substantially free of one or more additive components, or any combination thereof if more than one is present. Such components are selected from the group consisting of: polymers (e.g., nonionic, cationic, or anionic polymers), oxygen scavengers, quaternary ammonium compounds (e.g., salts or hydroxides), amines, and basic bases (e.g., NaOH, KOH, LiOH, Mg(OH)₂, and Ca(OH)₂). 2) Surfactants (e.g., cationic, anionic, or nonionic surfactants), defoamers, fluorinated compounds (e.g., fluorinated compounds or fluorinated compounds (e.g., fluorinated polymers / surfactants)), silica compounds, such as silanes (e.g., alkoxysilanes), nitrogen compounds (e.g., amino acids, amines, imines (e.g., amides, such as 1,8-diazabicyclo[5.4.0]-7-undecene (DBU) and 1,5-diazabicyclo[4.3.0]non-5-ene (DBN))), abrasives (e.g., cerium oxide abrasives, nonionic abrasives, surface-modified abrasives, or negatively / positively charged abrasives), 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., polyelectrolytes), silicates, cyclic compounds (e.g., azoles (e.g., diazoles, triazoles, or tetraazoles), triazoles, and cyclic compounds containing at least two rings, such as substituted or unsubstituted naphthalenes, or substituted or unsubstituted biphenyl ethers), chelating agents, buffers, acids, such as 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, phosphoric acid, and phosphoric acid), salts (e.g., halide salts or metal salts), and catalysts (e.g., metal-containing catalysts). The term "substantially free" in the etching composition used herein refers to components not intentionally added to the etching composition. In some embodiments, the etching composition described herein has one or more of the components substantially absent from the aforementioned etching composition, up to about 1000 ppm (e.g., up to about 500 ppm, up to about 250 ppm, up to about 100 ppm, up to about 50 ppm, up to about 10 ppm, or up to about 1 ppm). In some embodiments, the etching composition described herein may be completely free of one or more of the aforementioned components.

[0033] The etch composition disclosed herein can be prepared by simply mixing the components together, or by combining two components in a kit (each containing some of the components of the etch composition described herein).

[0034] In some embodiments, the present disclosure is characterized by a method for etching a semiconductor substrate containing at least one Si film. The method may include contacting one of the semiconductor substrates containing the at least one Si film with the etching composition of the present disclosure to substantially remove the Si film. 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. In some embodiments, the method substantially does not remove metal conductors (e.g., Cu), gate materials (e.g., SiGe), or dielectric materials (e.g., SiN, polysilicon, or SiCO) from the semiconductor substrate. For example, the method does not remove more than about 5% by weight (e.g., no more than about 3% by weight or no more than about 1% by weight) of the metal conductors or dielectric materials from the semiconductor substrate.

[0035] In some embodiments, the etching method includes the following steps: (A) providing a semiconductor substrate containing a Si film; (B) contacting the semiconductor substrate with the etching composition described herein; (C) rinsing the semiconductor substrate with one or more suitable rinsing solvents; and (D) optionally drying the semiconductor substrate (e.g., by any suitable means that can remove the rinsing solvent without compromising the integrity of the semiconductor substrate).

[0036] The semiconductor substrate containing the Si film to be etched in this method may contain organic and inorganic metal residues and some metal oxides, some or all of which may also be removed during the etching process.

[0037] The semiconductor substrate (e.g., wafer) described herein is typically composed of silicon, silicon-germanium, group 3-5 compounds such as GaAs, or any combination thereof. The semiconductor substrate may additionally contain exposed integrated circuit structures, such as interconnects (e.g., metal lines and dielectric materials). Metals and metal alloys used for interconnects include, but are not limited to, aluminum, aluminum-copper alloys, copper, titanium, tantalum, cobalt, silicon, titanium nitride, tantalum nitride, and tungsten. The semiconductor substrate may also include interlayer dielectrics, polycrystalline silicon, silicon oxide, silicon nitride, silicon-germanium, silicon carbide, titanium oxide, and carbon-doped silicon oxide layers.

[0038] The semiconductor substrate may come into contact with the etching composition by any suitable method, such as placing the etching composition in a tank and immersing and / or submerging the semiconductor substrate in the etching composition, spraying the etching composition onto the semiconductor substrate, allowing the etching composition to flow onto the semiconductor substrate, or any combination thereof.

[0039] The etch composition disclosed herein can be effectively used at temperatures up to about 85°C (e.g., from about 20°C to about 80°C, from about 55°C to about 65°C, or from about 60°C to about 65°C). Within this range, the etch rate of Si increases with temperature, so processes at higher temperatures can run for shorter times. Conversely, lower etch temperatures typically require longer etch times.

[0040] Etching time can vary over a wide range depending on the specific etching method, thickness, and temperature used. When etching in an immersion batch process, a suitable time range is, for example, up to about 10 minutes (e.g., from about 1 minute to about 7 minutes, from about 1 minute to about 5 minutes, or from about 2 minutes to about 4 minutes). The etching time for a single wafer process can range from about 30 seconds to about 5 minutes (e.g., from about 30 seconds to about 4 minutes, from about 1 minute to about 3 minutes, or from about 1 minute to about 2 minutes).

[0041] To further improve the etching capability of the etch composition disclosed herein, mechanical stirring may be employed. Examples of suitable stirring methods include circulating the etch composition on the substrate during etching, flowing or spraying the etch composition onto the substrate, and stirring using ultrasonic or megasonic waves. The orientation of the semiconductor substrate relative to the ground can be any angle. Preferably, it is horizontal or vertical.

[0042] After etching, the semiconductor substrate may be rinsed with a suitable rinsing solvent for approximately 5 seconds to approximately 5 minutes, with or without agitation. Multiple rinsing steps using different rinsing solvents may be employed. Examples of suitable rinsing solvents include, but are not limited to, deionized (DI) water, methanol, ethanol, isopropanol, N-methylpyrrolidone, γ-butyrolactone, dimethyl sulfoxide, ethyl lactate, and propylene glycol monomethyl ether acetate. Alternatively or otherwise, an aqueous rinsing solution with a pH > 8 (e.g., a dilute aqueous solution of ammonium hydroxide) may be used. The rinsing solvent may be applied in a manner similar to that used for applying the etching composition described herein. The etching composition may have been 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.

[0043] Optionally, after the rinsing step, the semiconductor substrate is dried. Any suitable drying method known in the art may be used. Examples of suitable drying methods include rotary drying, passing a drying gas through the semiconductor substrate, heating the semiconductor substrate using a heating device (e.g., a hot plate or infrared lamp), Maragoni drying, Rotagoni drying, IPA drying, and any combination thereof. The drying time depends on the specific method used, but is typically from about 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 wafer) from a semiconductor substrate obtained by the above method.

[0045] Although the present invention has been described in detail with reference to certain embodiments, it will be understood that modifications and variations are within the spirit and scope of the description and claims.

[0046] The following examples are provided to more clearly illustrate the principles and implementation of this disclosure. It should be understood that this disclosure is not limited to the examples described. Example General Procedure 1 Formulation Blending

[0047] While stirring, the remaining components of the formulation are added to the solvent calculated by vector to prepare an etched composition sample. General Procedure 2 Materials and Methods

[0048] Using commercially available unpatterned 300mm diameter wafers, 0.5” x 1.0” test pieces were cut for evaluation, and the etch rate of the cover film on the film was measured. The main cover film materials used for testing included 1) a polycrystalline silicon (polycrystalline Si) film with a thickness of about 1000Å deposited on a silicon substrate; 2) a SiN film with a thickness of about 600Å deposited on a silicon substrate; and 3) a SiO X film with a thickness of about 1200Å deposited on a silicon substrate.

[0049] The thickness of the cover film test piece before and after treatment is measured to determine the cover film etching rate. For polycrystalline Si, SiN, and SiOx cover films, the ellipsometry of Woollam VASE is used to measure the film thickness before and after treatment. General procedure 3: Etching evaluation is performed using a beaker test.

[0050] All cover film etching tests were conducted in 600mL glass beakers containing 200g of sample solution at 75°C with continuous stirring at 250rpm, using Parafilm® throughout to minimize evaporation loss. All cover film test pieces with one side exposed to the sample solution were cut into 0.5” x 1.0” square test piece sizes using a diamond scriber for beaker-scale testing. Each individual test piece was held in place using a single 4” long locking plastic tweezer. The test piece, with one side held by the locking tweezer, was suspended in a 600mL HDPE beaker and immersed in 200g of test solution, while the solution was continuously stirred at 75°C at 250rpm. After placing each sample in the stirred solution, the top of the 600mL HDPE beaker was immediately covered with Parafilm® and sealed again. The test pieces were kept still in the stirred solution until the processing time (0.5 minutes or 60 minutes) was completed.

[0051] After the treatment time in the test solution is completed, immediately remove the sample from the 600 mL HDPE beaker and rinse. Specifically, immerse the sample in 300 mL of ultra-high purity deionized (DI) water for 15 seconds with gentle stirring, then immerse it in 300 mL of isopropanol (IPA) for 15 seconds with gentle stirring, and finally immerse it in 300 mL of IPA for 15 seconds with gentle stirring. After the final IPA rinsing step, all test pieces are treated with a handheld nitrogen blower for a filtered nitrogen purging step. This blower forcibly removes all traces of IPA to produce a final dry sample for testing and measurement. Example 1

[0052] Formulation Example 1 (FE-1) was prepared according to general procedure 1 and evaluated according to general procedures 2 and 3. The formulation of FE-1 is summarized in Table 1. Table 1 Composition FE-1 20% by weight ETMAH aqueous solution 25% by weight 2-(2-aminoethoxy)ethanol 34% by weight glycerin 20% by weight SiGe inhibitors 0.9% by weight SiN inhibitors 0.1% by weight DI water 20% by weight total 100% by weight ETMAH = Ethyltrimethylammonium hydroxide

Claims

1. An etching composition comprising: at least one quaternary ammonium hydroxide or a salt thereof; at least one alkanolamine; at least one SiGe corrosion inhibitor comprising 11-mercaptoundecylphosphonic acid, 8-mercaptooctanoic acid, 6-mercaptohexanoic acid, 12-mercaptododecanoic acid, 8-quinolineboronic acid, 8-aminequinoline, 8-quinolinecarboxylic acid, 8-quinolinethiol, 2,8-quinolinediol, 8-quinolineacetic acid, 8-quinolinesulfonic acid, 2-methyl-8-quinolineol, 5-hydroxyquinoline or 6-hydroxyquinoline; at least one organic solvent; and water.

2. The composition of claim 1, wherein the at least one quaternary ammonium hydroxide or its salt comprises tetraalkylammonium hydroxide or its salt.

3. The composition of claim 1, wherein the at least one quaternary ammonium hydroxide or its salt comprises tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, benzyltrimethylammonium hydroxide, methyltriethylammonium hydroxide, ethyltrimethylammonium hydroxide, 2-hydroxyethyltrimethylammonium hydroxide, benzyltriethylammonium hydroxide, hexadecyltrimethylammonium hydroxide, or salts thereof.

4. The composition of claim 1, wherein the amount of the at least one quaternary ammonium hydroxide or its salt accounts for about 0.1% to about 10% by weight of the composition.

5. The composition of claim 1, wherein the at least one alkanolamine comprises N-methylethanolamine, monoethanolamine, diethanolamine, triethanolamine, triisopropanolamine, 2-(2-aminoethylamino)ethanol, 2-(2-aminoethoxy)ethanol, N-ethylethanolamine, N,N-dimethylethanolamine, N,N-diethylethanolamine, N-methyldiethanolamine, N-ethyldiethanolamine, diisopropanolamine, or cyclohexylamine diethanolamine.

6. The composition of claim 1, wherein the at least one alkanolamine is present in an amount of about 0.01% by weight to about 10% by weight of the composition.

7. The composition of claim 1, wherein the amount of the at least one SiGe corrosion inhibitor is from about 0.01% to about 3% by weight of the composition.

8. The composition of claim 1, wherein the at least one organic solvent comprises an alcohol or an alkyl diol ether.

9. The composition of claim 8, wherein the at least one organic solvent comprises glycerol, propylene glycol, hexylene glycol, 1,3-propanediol, ethylene glycol butyl ether, 3-methoxy-3-methyl-1-butanol, acetone, cyclohexanone, ethyl acetate, or propylene glycol monoethyl ether acetate.

10. The composition of claim 1, wherein the amount of the at least one organic solvent is from about 5% by weight to about 75% by weight of the composition.

11. The composition of claim 1, wherein the amount of water accounts for about 25% to about 95% by weight of the composition.

12. The composition of claim 1 further comprises at least one polymeric naphthalene sulfonic acid.

13. The composition of claim 12, wherein the at least one polymeric naphthalene sulfonic acid comprises a sulfonic acid having the following structure: wherein n is 3 to 6.

14. The composition of claim 12, wherein the amount of the at least one polymeric naphthalenesulfonic acid is from about 0.01% to about 3% by weight of the composition.

15. The composition of claim 1, wherein the composition has a pH of about 4 to about 8.

16. An etching composition comprising: at least one quaternary ammonium hydroxide or a salt thereof; at least one alkanolamine; at least one SiGe corrosion inhibitor comprising a mercapto acid, a substituted quinoline or a salt thereof; at least one polymeric naphthalenesulfonic acid; at least one organic solvent; and water.

17. A composition of claim 16, wherein the mercapto acid comprises a mercaptophosphoric acid or a mercaptocarboxylic acid.

18. A composition of claim 17, wherein the mercapto acid comprises 11-mercaptoundecylphosphonic acid, 8-mercaptooctanoic acid, 6-mercaptohexanoic acid, 11-mercaptoundecanoic acid or 12-mercaptododecanoic acid.

19. A composition of claim 16, wherein the substituted quinoline comprises a quinoline substituted with an OH, NH₂, COOH, SH, CH₂COOH, SO₃H or borate group.

20. A composition of claim 19, wherein the substituted quinoline comprises 8-quinoline boric acid, 8-aminoquinoline, 8-quinoline carboxylic acid, 8-quinoline thiol, 2,8-quinolinediol, 8-quinoline acetic acid, 8-quinoline sulfonic acid, 2-methyl-8-quinoline alcohol, 5-hydroxyquinoline, 6-hydroxyquinoline or 8-hydroxyquinoline.

21. A method comprising: contacting a semiconductor substrate containing a Si film with a composition as claimed in claim 1 to substantially remove the Si film.

22. The method of claim 21, wherein the method substantially does not remove SiN or SiGe.

23. An article formed by the method of claim 21, wherein the article is a semiconductor device.

24. The article of claim 23, wherein the semiconductor device is an integrated circuit.