Etching Composition

Abstract

The present disclosure relates to etching compositions that are useful, for example, for selectively removing cobalt (Co) from semiconductor substrates without substantially forming cobalt oxide by-products.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Provisional Patent Application No. 62 / 841,305, filed May 1, 2019, the entire contents of which are incorporated herein by reference.

[0002] The present disclosure relates to etching compositions and methods of using the etching compositions. In particular, the present disclosure relates to etching compositions capable of selectively etching cobalt (Co) without substantially forming a passive layer on the etched substrate. [Background technology]

[0003] In the semiconductor industry, the size and density of electronic circuits and components in microelectronic devices, silicon chips, liquid crystal displays, MEMS (microelectromechanical systems), printed wiring boards, etc. are rapidly decreasing and increasing. The integrated circuits therein are layered or stacked, and the thickness of the insulating layers between each circuit layer continues to decrease, resulting in smaller and smaller feature sizes. As the feature sizes decrease, the patterns become smaller and the device performance parameters become more stringent and robust. As a result, various problems that were previously acceptable are no longer acceptable or have become increasingly problematic as the feature sizes decrease.

[0004] In the manufacture of advanced integrated circuits, both high-k and low-k dielectrics, as well as combination barrier layer materials, have been used to minimize problems associated with increasing density and to optimize performance. Summary of the Invention [Problem to be solved by the invention]

[0005] Cobalt (Co) is used in semiconductor devices, liquid crystal displays, MEMS (microelectromechanical systems), printed wiring boards, etc., as a ground layer and capping layer for precious metals, aluminum (Al) and copper (Cu) wiring. In semiconductor devices, it can be used as a metal contact, interconnect, trench fill or capping layer. In the construction of devices for these applications, it is often necessary to etch Co. In many types of Co applications and device environments, other layers are in contact or exposed at the same time that Co is being etched. Highly selective etching of Co in the presence of these other materials (e.g., metal conductors, dielectrics and hard marks) is essential for device yield and long life. [Means for solving the problem]

[0006] The present disclosure is based on the unexpected discovery that certain etching compositions can selectively etch Co without substantially forming cobalt oxide by-products (e.g., a passive CoOx hydroxide layer (e.g., on a Co or CoOx layer) or excess amounts of CoOx) in semiconductor devices, thereby improving uniformity as well as enabling efficient Co etching with low or no residual CoOx hydroxide (CoOx-OH).

[0007] In one aspect, the present disclosure provides a compound of formula (I): R1-ON-R2R3, where each of R1, R2, and R3 is independently H or C1-C6 alkyl; 2) at least one unsaturated C3-C6 alkyl; 12 The etching composition includes: carboxylic acid; 3) at least one leveling agent; and 4) water.

[0008] In another aspect, the disclosure features a method that includes contacting a semiconductor substrate including Co features with an etching composition described in this disclosure to remove at least a portion of the Co features.

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

[0010] As defined in this disclosure, unless otherwise specified, all percentages expressed are to be understood as being weight percentages based on the total weight of the composition. Ambient temperature is defined to be between about 16 degrees Celsius and about 27 degrees Celsius (° C.), unless otherwise specified.

[0011] As defined in this disclosure, a "water-soluble" substance (e.g., a water-soluble alcohol, ketone, ester, ether, etc.) means a substance that has a solubility of at least 0.5% by weight (e.g., at least 1% by weight or at least 5% by weight) in water at 25°C.

[0012] In this disclosure, tautomerization is defined as the formal migration of a hydrogen atom or proton accompanied by the switching of a single and adjacent double bond. A description, description or claim of a triazole compound also includes tautomers of the triazole compound due to the low activation energy for tautomerization in the triazole ring system.

[0013] In general, the disclosure provides: 1) a compound of formula (I): R1-ON-R2R3, where in formula (I), each of R1, R2, and R3 is independently H or C1-C6 alkyl; 2) at least one unsaturated C3-C6 alkyl; 12 The present invention features an etching composition (e.g., an etching composition for selectively removing or etching Co) comprising (e.g., comprises, consists essentially of, or consists of) a carboxylic acid; 3) at least one leveling agent; and 4) water.

[0014] The etching composition of the present disclosure may include at least one (e.g., two, three, or four) compounds of formula (I): R1-ON-R2R3, where in formula (I), each of R1, R2, and R3 is independently H or C1-C6 alkyl (e.g., methyl, ethyl, propyl, isopropyl, n-butyl, or t-butyl). Examples of suitable compounds of formula (I) include hydroxylamine, N-tert-butyl-hydroxylamine, and N,O-dimethylhydroxylamine.

[0015] In some embodiments, the at least one compound of formula (I) can be at least about 0.01 wt% (e.g., at least about 0.05 wt%, at least about 0.1 wt%, at least about 0.2 wt%, at least about 0.3 wt%, at least about 0.4 wt%, at least about 0.5 wt%, at least about 0.6 wt%, at least about 0.7 wt%, at least about 0.8 wt%, at least about 0.9 wt%, or at least about 1 wt%) to at most about 10 wt% (e.g., at most about 8 wt%, at most about 6 wt%, at most about 5 wt%, at most about 4 wt%, at most about 2 wt%, at most about 1 wt%, or at most about 0.8 wt%) of the total weight of the etching composition. Without wishing to be bound by theory, it is believed that the compound of formula (I) can form an intermediate with Co during the etching process to facilitate and enhance the removal of Co on the semiconductor substrate.

[0016] Generally, the etching compositions of the present disclosure contain at least one (e.g., two, three, or four) unsaturated C3-C 12 In some embodiments, the unsaturated C3-C 12The carboxylic acid can include one or more (e.g., two or three) carbon-carbon double bonds or carbon-carbon triple bonds and / or one or more (e.g., two or three) carboxylic acid groups. In some embodiments, the unsaturated carboxylic acid can be non-aromatic and / or acyclic (e.g., having no ring structure). In some embodiments, the unsaturated carboxylic acid can include one or more heteroatoms (e.g., N, O, or S) in addition to the oxygen atom in the carboxyl group. In some embodiments, the unsaturated carboxylic acid can be represented by the formula (II): R-(COOH) n In the formula (II), n is 1, 2, or 3, and R is a C-C 11 alkenyl or C2-C 11 and wherein the alkenyl or alkynyl is optionally substituted with C1-C4 alkyl, aryl (e.g., phenyl), or heteroaryl (e.g., furyl). For example, the unsaturated carboxylic acid can include acrylic acid, crotonic acid, 2-pentenoic acid, trans-2-hexenoic acid, fumaric acid, 10-undecenoic acid, 2-methyl-2-pentenoic acid, 2-pentenoic acid, 2-methyl-4-pentenoic acid, 2-octenoic acid, and 3-(2-furyl)acrylic acid.

[0017] In some embodiments, the at least one unsaturated C3-C 12 The carboxylic acid can be at least about 0.01 wt.% (e.g., at least about 0.02 wt.%, at least about 0.05 wt.%, at least about 0.1 wt.%, at least about 0.2 wt.%, or at least about 0.5 wt.%) to at most about 3 wt.% (e.g., at most about 2.5 wt.%, at most about 2 wt.%, at most about 1.5 wt.%, at most about 1 wt.%, at most about 0.8 wt.%, or at most about 0.5 wt.%) of the total weight of the etching composition. Without wishing to be bound by theory, it is believed that the unsaturated carboxylic acid can reduce or prevent the formation of a secondary passive CoOx hydroxide layer on the CoOx layer or the formation of an excess amount of CoOx on the semiconductor substrate.

[0018] In some embodiments, the etching compositions of the present disclosure may include at least one leveling agent. As used in this disclosure, the term "leveling agent" refers to an organic compound capable of providing a substantially planar metal layer. In some embodiments, the at least one leveling agent may include a polymer, such as, for example, a sulfur-containing polymer or a nitrogen-containing polymer. Examples of leveling agents include poly(4-styrenesulfonic acid), polyethyleneimine, polyglycine, poly(allylamine), polyaniline, sulfonated polyaniline, polyurea, polyacrylamide, poly(melamine-co-formaldehyde), polyaminoamide, or polyalkanolamine.

[0019] In some embodiments, the at least one leveling agent can be at least about 0.01 wt. % (e.g., at least about 0.02 wt. %, at least about 0.05 wt. %, at least about 0.1 wt. %, at least about 0.2 wt. %, or at least about 0.5 wt. %) to at most about 3 wt. % (e.g., at most about 2.5 wt. %, at most about 2 wt. %, at most about 1.5 wt. %, at most about 1 wt. %, at most about 0.8 wt. %, or at most about 0.5 wt. %) of the total weight of the etching composition. Without wishing to be bound by theory, it is believed that the leveling agent can form a substantially planar metal layer on a semiconductor substrate.

[0020] In general, the etching compositions of the present disclosure can include water as a solvent. In some embodiments, the water can be deionized water and ultrapure water, can be free of organic contaminants, and can have a minimum resistivity of about 4 to about 7 megaohms, or at least about 17 megaohms. In some embodiments, the water can be in an amount of at least about 50% by weight (e.g., at least about 50% by weight, at least about 55% by weight, at least about 65% by weight, at least about 70% by weight, at least about 75% by weight, at least about 80% by weight, at least about 85% by weight, at least about 90% by weight, or at least about 95% by weight) up to about 99% by weight (e.g., up to about 98% by weight, up to about 97% by weight, up to about 95% by weight, up to about 90% by weight, up to about 85% by weight, up to about 80% by weight, up to about 75% by weight, or up to about 70% by weight) of the etching composition. While not wishing to be bound by theory, it is believed that when the amount of water is greater than 99% by weight of the composition, it adversely affects the Co etch rate and reduces Co removal in the etching process. However, while not 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 50% by weight) to keep all other components solubilized and avoid reducing etching performance.

[0021] In some embodiments, the etching composition of the present disclosure may optionally further comprise at least one (e.g., two, three, or four) Co etch accelerator. The Co etch accelerator may be selected from the group consisting of carboxylic acids or amino acids (e.g., those containing mono-, bi-, tri-, and polycarboxylic acid groups). In some embodiments, the Co etch accelerator may comprise a water-soluble carboxylic acid or a water-soluble amino acid. Examples of suitable Co etch accelerators may include citric acid, formic acid, acetic acid, oxalic acid, glycine, glycolic acid, malonic acid, lactic acid, and diethylenetriaminepentaacetic acid.

[0022] In some embodiments, the Co etch promoter is in an amount of at least about 0.01 wt. % (e.g., at least about 0.02 wt. %, at least about 0.05 wt. %, at least about 0.1 wt. %, at least about 0.2 wt. %, or at least about 0.5 wt. %) to at most about 3 wt. % (e.g., at most about 2.5 wt. %, at most about 2 wt. %, at most about 1.5 wt. %, at most about 1 wt. %, at most about 0.8 wt. %, or at most about 0.5 wt. %) of the etching composition. Without wishing to be bound by theory, it is believed that the Co etch promoter can facilitate the etching or removal of Co from a semiconductor substrate.

[0023] In some embodiments, the etching compositions of the present disclosure can optionally further comprise at least one (e.g., two, three, or four) organic solvent, which can be selected from the group consisting of water-soluble alcohols, water-soluble ketones, water-soluble esters, and water-soluble ethers.

[0024] Water-soluble alcohols include, but are not limited to, alkanediols (including but not limited to alkylene glycols), glycols, alkoxyalcohols (including but not limited to glycol monoethers), saturated aliphatic monohydric alcohols, unsaturated non-aromatic monohydric alcohols, and low molecular weight alcohols having a ring structure.

[0025] Examples of water-soluble alkanediols include, but are not limited to, 2-methyl-1,3-propanediol, 1,3-propanediol, 2,2-dimethyl-1,3-propanediol, 1,4-butanediol, 1,3-butanediol, 1,2-butanediol, 2,3-butanediol, pinacol, and alkylene glycols.

[0026] Examples of water soluble alkylene glycols include, but are not limited to, ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, triethylene glycol, and tetraethylene glycol.

[0027] Examples of water-soluble alkoxy alcohols include, but are not limited to, 3-methoxy-3-methyl-1-butanol, 3-methoxy-1-butanol, 1-methoxy-2-butanol, and water-soluble glycol monoethers.

[0028] Examples of water-soluble glycol monoethers include, but are not limited to, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono n-propyl ether, ethylene glycol monoisopropyl ether, ethylene glycol mono n-butyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monobutyl ether, 1-methoxy-2-propanol, 2-methoxy-1-propanol, 1-ethoxy-2-propanol, 2-ethoxy-1-propanol, propylene glycol mono-n-propyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monobutyl ether, dipropylene glycol mono-n-propyl ether, tripropylene glycol monoethyl ether, tripropylene glycol monomethyl ether, ethylene glycol monobenzyl ether, and diethylene glycol monobenzyl ether.

[0029] Examples of water-soluble saturated aliphatic monohydric alcohols include, but are not limited to, methanol, ethanol, n-propyl alcohol, isopropyl alcohol, 1-butanol, 2-butanol, isobutyl alcohol, tert-butyl alcohol, 2-pentanol, t-pentyl alcohol, and 1-hexanol.

[0030] Examples of water-soluble unsaturated non-aromatic monohydric alcohols include, but are not limited to, allyl alcohol, propargyl alcohol, 2-butenyl alcohol, 3-butenyl alcohol, and 4-penten-2-ol.

[0031] Examples of low molecular weight alcohols having a water-soluble ring structure include, but are not limited to, tetrahydrofurfuryl alcohol, furfuryl alcohol, and 1,3-cyclopentanediol.

[0032] Examples of water-soluble ketones include, but are not limited to, acetone, propanone, cyclobutanone, cyclopentanone, cyclohexanone, diacetone alcohol, 2-butanone, 5-hexanedione, 1,4-cyclohexanedione, 3-hydroxyacetophenone, 1,3-cyclohexanedione, and cyclohexanone.

[0033] Examples of water-soluble esters include, but are not limited to, ethyl acetate, glycol monoesters (e.g., ethylene glycol monoacetate, and diethylene glycol monoacetate), and glycol monoether monoesters (e.g., propylene glycol monomethyl ether acetate, ethylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, and ethylene glycol monoethyl ether acetate).

[0034] In some embodiments, the at least one organic solvent can be at least about 0.5 wt. % (e.g., at least about 1 wt. %, at least about 2 wt. %, at least about 4 wt. %, at least about 5 wt. %, at least about 6 wt. %, at least about 8 wt. %, or at least about 10 wt. %) to up to about 30 wt. % (e.g., up to about 25 wt. %, up to about 20 wt. %, up to about 18 wt. %, up to about 16 wt. %, up to about 15 wt. %, up to about 14 wt. %, up to about 12 wt. %, or up to about 10 wt. %) of the total weight of the etching composition.

[0035] In some embodiments, the etching compositions of the present disclosure can optionally further include at least one (e.g., two, three, or four) pH adjuster, e.g., an acid or a base. In some embodiments, the pH adjuster can be a metal ion-free base. Suitable metal ion-free bases include quaternary ammonium hydroxides (e.g., tetraalkylammonium hydroxides such as TMAH), ammonium hydroxides, amines (including alkanolamines), amidines (e.g., 1,8-diazabicyclo[5.4.0]-7-undecene (DBU) and 1,5-diazabicyclo[4.3.0]-5-nonene (DBN)), and guanidine salts (e.g., guanidine carbonate). In some embodiments, the base is not a quaternary ammonium hydroxide (e.g., tetraalkylammonium hydroxides such as TMAH).

[0036] In some embodiments, the pH adjuster can be an organic acid, such as a sulfonic acid (eg, methanesulfonic acid, trifluoromethanesulfonic acid, and p-toluenesulfonic acid).

[0037] In some embodiments, when the pH adjuster is an organic acid, the organic acid is not an unsaturated carboxylic acid as described above, or a saturated carboxylic acid containing one or more (e.g., two, three, or four) carboxyl groups (e.g., citric acid, oxalic acid, or acetic acid). In some embodiments, the pH adjuster is not a hydrogen halide.

[0038] In general, the pH adjuster in the etching composition of the present disclosure can be in an amount sufficient to adjust the pH of the etching composition to a desired value. In some embodiments, the pH adjuster can be at least about 0.01 wt.% (e.g., at least about 0.05 wt.%, at least about 0.1 wt.%, at least about 0.5 wt.%, at least about 1 wt.%, or at least about 2 wt.%) to at most about 6 wt.% (e.g., at most about 5.5 wt.%, at most about 5 wt.%, at most about 4 wt.%, at most about 3 wt.%, at most about 2 wt.%, or at most about 1 wt.%) of the total weight of the etching composition.

[0039] In some embodiments, the etching compositions of the present disclosure can have a pH of at least about 0 (e.g., at least about 0.2, at least about 0.4, at least about 0.5, at least about 0.6, at least about 0.8, at least about 1, at least about 1.5, at least about 2, at least about 2.5, or at least about 3) and / or up to about 7 (e.g., up to about 6.5, up to about 6, up to about 5.5, up to about 5, up to about 4.5, up to about 4, up to about 3.5, or up to about 3). Without wishing to be bound by theory, it is believed that etching compositions having a pH higher than 7 do not have sufficient Co etch rates. Furthermore, it is believed that etching compositions having a pH lower than 0 may cause excessive Co etching, inhibit the action of certain components in the composition (e.g., metal corrosion inhibitors), or decompose certain components in the composition due to the strong acidity.

[0040] In addition, in some embodiments, the etching compositions of the present disclosure may include optional additives such as additional corrosion inhibitors, surfactants, additional organic solvents, biocides, and antifoaming agents. 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 (e.g., 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, or amphoteric.

[0041] For example, the etching compositions of the present disclosure may include at least one (e.g., two, three, or four) metal corrosion inhibitor. Examples of corrosion inhibitors include substituted or unsubstituted azole compounds, such as triazole compounds, imidazole compounds, and tetrazole compounds. Triazole compounds may include triazoles, benzotriazoles, substituted triazoles, and substituted benzotriazoles. Examples of triazole compounds include, but are not limited to, 1,2,4-triazoles, 1,2,3-triazoles, or triazoles substituted with substituents such as C1-C8 alkyl groups (e.g., 5-methyltriazole), amino groups, thiol groups, mercapto groups, imino groups, carboxy groups, and nitro groups. Specific examples include tolyltriazole, 5-methyl-1,2,4-triazole, 3-amino-5-mercapto-1,2,4-triazole, 1-amino-1,2,4-triazole, 1-amino-1,2,3-triazole, 1-amino-5-methyl-1,2,3-triazole, 3-amino-1,2,4-triazole, 3-mercapto-1,2,4-triazole, and 3-isopropyl-1,2,4-triazole.

[0042] In some embodiments, the at least one metal corrosion inhibitor can include a benzotriazole optionally substituted with at least one substituent selected from the group consisting of an alkyl group, an aryl group, a halogen group, an amino group, a nitro group, an alkoxy group, and a hydroxyl group. Examples include benzotriazole, 5-aminobenzotriazole, hydroxybenzotriazole (e.g., 1-hydroxybenzotriazole), 5-phenylthiol-benzotriazole, halo-benzotriazoles (halo=F, Cl, Br, or I) (e.g., 5-chlorobenzotriazole, 4-chlorobenzotriazole, 5-bromobenzotriazole, 4-bromobenzotriazole, 5-fluorobenzotriazole, and 4-fluorobenzotriazole), naphthotriazole, tolyltriazole, 5-phenyl-benzotriazole, 5-nitrobenzotriazole, 4-nitrobenzotriazole, 3-amino-5-mercapto-1,2,4-triazole, 2-(5-amino-pentyl)-benzotriazole, 1-amino-benzotriazole, 5-methyl-1H-benzotriazole, benzotriazole-5-carboxylic acid, 4-methylbenzotriazole, 4-ethylbenzotriazole, 5-ethylbenzotriazole, benzotriazole, 4-propylbenzotriazole, 5-propylbenzotriazole, 4-isopropylbenzotriazole, 5-isopropylbenzotriazole, 4-n-butylbenzotriazole, 5-n-butylbenzotriazole, 4-isobutylbenzotriazole, 5-isobutylbenzotriazole, 4-pentylbenzotriazole, 5-pentylbenzotriazole, 4-hexylbenzotriazole, 5-hexylbenzotriazole, 5-methoxybenzotriazole, 5-hydroxybenzotriazole, dihydroxypropylbenzotriazole, 1-[N,N-bis(2-ethylhexyl)aminomethyl]-benzotriazole, 5-t-butylbenzotriazole, 5-(1',1'-dimethylpropyl)-benzotriazole, 5-(1',1',3'-trimethylbutyl)benzotriazole, 5-n-octylbenzotriazole, and 5-(1',1',3',3'-tetramethylbutyl)benzotriazole.

[0043] Examples of imidazole compounds include, but are not limited to, 2-alkyl-4-methylimidazole, 2-phenyl-4-alkylimidazole, 2-methyl-4(5)-nitroimidazole, 5-methyl-4-nitroimidazole, 4-imidazole methanol hydrochloride, and 2-mercapto-1-methylimidazole.

[0044] Examples of the tetrazole compound include 1-H-tetrazole, 5-methyl-1H-tetrazole, 5-phenyl-1H-tetrazole, 5-amino-1H-tetrazole, 1-phenyl-5-mercapto-1H-tetrazole, 5,5'-bis-1H-tetrazole, 1-methyl-5-ethyltetrazole, 1-methyl-5-mercaptotetrazole, 1-carboxymethyl-5-mercaptotetrazole, and the like.

[0045] In some embodiments, the at least one metal corrosion inhibitor can be at least about 50 ppm or about 0.005 wt. % (e.g., at least about 0.01 wt. %, at least about 0.02 wt. %, at least about 0.05 wt. %, at least about 0.1 wt. %, at least about 0.2 wt. %, or at least about 0.5 wt. %), to at most about 3 wt. % (e.g., at most about 2.5 wt. %, at most about 2 wt. %, at most about 1.5 wt. %, at most about 1 wt. %, at most about 0.8 wt. %, or at most about 0.5 wt. %) of the total weight of the etching composition.

[0046] In general, the etching compositions of the present disclosure can have a relatively high Co / dielectric material (e.g., SiN, polysilicon, high-k dielectrics, AlOx, SiOx, or SiCO) etch selectivity (i.e., a high ratio of the Co etch rate to the etch rate of the dielectric material). In some embodiments, the etching compositions can have a Co / dielectric material 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).

[0047] In some embodiments, the etching compositions of the present disclosure may specifically exclude one or more additive components, in any combination if more than one. Such components include organic solvents, pH adjusters, polymers (e.g., cationic polymers or anionic polymers), oxygen scavengers, quaternary ammonium salts (including quaternary ammonium hydroxides), amines, alkaline bases (e.g., NaOH, KOH, and LiOH), surfactants other than antifoaming agents, antifoaming agents, fluorine-containing compounds, oxidizers (e.g., peroxides, hydrogen peroxide, inorganic oxidizers (e.g., ferric nitrate, potassium iodate, potassium permanganate, and nitric acid), ammonium chlorite, ammonium chlorate, ammonium iodate, ammonium perborate, ammonium perchlorate, ammonium periodate, ammonium persulfate, tetramethylammonium chlorite, tetramethylammonium chlorate, tetramethylammonium iodate, tetramethylammonium perborate, tetramethylammonium perchlorate, tetramethylammonium periodate, tetramethylammonium persulfate, and aqueous urea peroxide. and peracids (e.g., peracetic acid), abrasives (e.g., cationic or anionic abrasives), silicates, hydroxycarboxylic acids (e.g., those containing more than two hydroxyl groups), carboxylic acids and polycarboxylic acids (e.g., those with or without amino groups), silanes (e.g., alkoxysilanes), cyclic compounds (e.g., cyclic compounds containing at least two rings such as azoles (such as diazoles, triazoles, or tetrazoles), triazines, and substituted or unsubstituted naphthalenes or substituted or unsubstituted biphenyl ethers), buffers, non-azole corrosion inhibitors, azoles (e.g., diazoles, triazoles, or tetrazoles), and salts (e.g., sulfates, sulfonates, halide salts (e.g., chloride salts), nitrates, acetates, phosphates, and metal salts such as metal halides, potassium salts (e.g., potassium nitrate, sodium salts, and silver salts).

[0048] The etching composition of the present disclosure can be prepared by simply mixing the components, or by compounding two compositions in a kit. The first composition in the kit can be an aqueous solution containing one or more of the components. The second composition in the kit can contain the remaining components of the etching composition of the present disclosure in concentrated form and in a predetermined ratio, such that compounding the two compositions provides the desired etching composition of the present disclosure.

[0049] In some embodiments, the disclosure features a method of etching a semiconductor substrate including at least one Co feature (e.g., a Co film or Co layer) and removing at least a portion of the Co feature. In some embodiments, the Co feature can be a Co-filled via or a Co-filled trench. In some embodiments, the method can remove at least about 10% (e.g., at least about 20%, at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 90%, or 100%) of the Co feature (e.g., Co filled in a via or trench).

[0050] In some embodiments, the method can include contacting the semiconductor substrate including at least one Co feature with an etching composition of the present disclosure to remove at least a portion of the Co feature. 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.

[0051] In some embodiments, an advantage of the method described in the present disclosure is that it does not substantially form a cobalt hydroxide (CoOx hydroxide, or CoOx-OH) layer on the CoOx layer on the semiconductor substrate exposed to the etching composition. For example, the method does not form a CoOx hydroxide layer on the semiconductor substrate of more than about 5 Å (e.g., more than about 3 Å, or more than about 1 Å). Without wishing to be bound by theory, it is believed that the CoOx-OH layer can be dark in color and can be a non-uniform porous oxide of various thicknesses that can cause non-uniform etching. Therefore, such secondary oxide layers are generally undesirable on typical Co / CoO metal surfaces.

[0052] In some embodiments, other advantages of the methods described herein include the ability to selectively and uniformly remove Co and / or etch Co to a desired depth or thickness, and in some embodiments, the methods can provide a Co surface without roughness after etching.

[0053] In some embodiments, the etching method comprises: (A) providing a semiconductor substrate including Co features; (B) contacting the semiconductor substrate with an 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 removes the rinsing solvent and does not compromise the integrity of the semiconductor substrate); Includes.

[0054] The semiconductor substrate (e.g., wafer) described in this disclosure is typically constructed from silicon, silicon germanium, group 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 dielectric materials). Metals and metal alloys used in interconnect 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 substrate may include layers of interlayer dielectrics, polysilicon, silicon oxide, silicon nitride, silicon carbide, titanium oxide, and carbon-doped silicon oxide.

[0055] Contacting the semiconductor substrate with the etching composition may be accomplished in any suitable manner, such as by placing the etching composition in a tank 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.

[0056] The etching compositions of the present disclosure 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.). The etch rate of Co increases with temperature within this range, and therefore, at higher temperatures the process can be carried out in shorter times. Conversely, etches at lower temperatures typically require longer etch times.

[0057] Etching times can vary over a wide range depending on the particular etching method, thickness, and temperature used. When etching is performed in an immersion batch type process, a suitable time range is, for example, up to about 10 minutes (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 5 minutes (e.g., about 30 seconds to about 4 minutes, about 1 minute to about 3 minutes, or about 1 minute to about 2 minutes). Etching times for cyclic processes (e.g., up to 16 cycles of etching, rinsing, and drying the wafer) can range from about 10 seconds to about 2 minutes per cycle.

[0058] Mechanical agitation means can be used to further improve the etching ability of the etching compositions of the present disclosure. Examples of suitable agitation means include circulation of the etching composition over the substrate, flowing or spraying 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 surface can be at any angle. Horizontal or vertical orientation is preferred.

[0059] Following the etching, the semiconductor substrate may be rinsed with a suitable rinsing solvent for a period of time ranging from about 5 seconds up to about 5 minutes, with or without agitation. Multiple rinsing steps using various rinsing solvents may be used. Examples of suitable rinsing solvents include, but are not limited to, deionized (DI) water, methanol, ethanol, isopropyl alcohol, N-methylpyrrolidone, gamma-butyrolactone, dimethylsulfoxide, ethyl lactate, and propylene glycol monomethyl ether acetate. Alternatively or additionally, an aqueous rinsing agent with a pH>8 may be used, such as, for example, a dilute aqueous ammonium hydroxide solution. Examples of rinsing solvents include, but are not limited to, a dilute aqueous ammonium hydroxide solution, DI water, methanol, ethanol, and isopropyl alcohol. The rinsing solvent may be applied using a means similar to that used to apply the etching compositions described herein. The etching composition may be removed from the semiconductor substrate prior to 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.

[0060] Optionally, the semiconductor substrate is dried after the rinsing step. Any suitable drying means known in the art may be used. Examples of suitable drying means include spin drying, flowing a drying gas over the semiconductor substrate, heating the semiconductor substrate using a heating means such as a hot plate or infrared lamps, Marangoni drying, Rotagoni drying, isopropyl alcohol (IPA) drying, or any combination thereof. Drying times vary depending on the specific method used, but are typically on the order of 30 seconds up to a few minutes.

[0061] 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 above-described method.

[0062] The present disclosure will be described 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 present disclosure. EXAMPLES

[0063] All percentages listed are by weight (wt %) unless otherwise noted. Testing was performed with controlled stirring at 325 rpm with a ½ inch stir bar unless otherwise noted.

[0064] General Procedure 1 Mixing the compound Samples of the etching composition were prepared by adding the remaining components of the formulation to the calculated amount of solvent with stirring. After a homogeneous solution was obtained, any optional additives were added.

[0065] General Procedure 2 Materials and Methods Blanket test coupons were evaluated for etching and material compatibility in the test solutions prepared according to General Procedure 1, following the procedures described in General Procedure 3.

[0066] Blanket film etch rate measurements were performed on commercial unpatterned 200 mm diameter wafers diced into 1.0 x 1.0 inch specimens for evaluation. The blanket film material used for testing was a Co film approximately 2000 Å thick deposited on a silicon substrate.

[0067] The blanket film coupons were measured for thickness before and after processing to determine the blanket film etch rate. The Co film thickness was measured before and after processing using a CDE RESMAP 4-point probe.

[0068] The CoOx-OH layer was measured using a Woolam ellipsometer as follows. First, the Co film with an inherent CoOx layer was measured based on the ellipsometry model using several pre-cleaned Co films, and it was confirmed that the CoOx layer with a thickness of about 10 Å was only detected on the opaque Co metal layer. Then, the CoOx layer was used as the first layer to establish a ellipsometry model for measuring the thickness of the CoOx-OH layer in the 10 Å CoOx layer. The existence of the CoOx layer and the CoOx-OH layer was confirmed by XPS.

[0069] General Step 3 Etching evaluation by beaker test All blanket film etching tests were performed at 50°C in a 125mL PTFE bottle containing 100g of sample solution in a 600mL glass beaker water bath with continuous stirring at 325 rpm, using a PTFE bottle cap seal during heating to minimize evaporation losses. All blanket specimens with blanket dielectric film exposed on one side to the sample solution were diced with a diamond scriber to 0.5 x 0.5 inch square specimen size for beaker scale testing. Each individual specimen was held in place with one 4 inch long locking plastic tweezers clip. The specimens with one edge held by the locking tweezers clip were suspended in a 125mL PTFE bottle and immersed in 100g of sample solution while the solution was continuously stirred at 325 rpm at 50°C. The PTFE bottle was open to the atmosphere only for the short duration of the test specimen treatment and was resealed with the bottle cap during any heating or treatment time delays.

[0070] The test specimens were secured in the stirred solution with the stationary clips in the exact same position for each test until the treatment time (e.g., 2 to 10 minutes) had elapsed. After the treatment time in the test solution had elapsed, the test specimens were immediately removed from the 125 mL PTFE bottles and rinsed twice with DI water for 10 seconds. After the final DI rinse step, all test specimens were given a blow-off step with filtered nitrogen gas using a handheld nitrogen gas blower, which forced out all traces of DI water and provided the final dry sample for test measurement.

[0071] Example 1 Formulation Examples 1-9 (FE-1-FE-9) and Comparative Formulation Example 1 (CFE-1) were made according to General Procedure 1 and evaluated according to General Procedures 2 and 3. The formulations and test results are summarized in Table 1.

[0072] [Table 1]

[0073] As shown in Table 1, formulations FE-1, FE-2, FE-5, FE-8 and FE-9 exhibited relatively high Co etch rates, produced a mirror surface on the Co metal film, and did not result in a passive CoOx-OH layer. In contrast, formulation CF-1 exhibited a high Co etch rate, but the Co metal film was damaged or destroyed beyond ellipsometry reading.

[0074] 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 the invention described and claimed. The present invention may include the following embodiments. <1> 1) Formula (I): R 1 -ONR 2 R 3 In the above formula (I), R 1 、R 2 and R 3 each independently is H or C 1 -C 6 is an alkyl group; 2) At least one unsaturated C 3-C 12 Carboxylic acids; 3) at least one leveling agent; and 4) water, 1. An etching composition comprising: <2> The composition has a pH of about 0 to about 7. <1> The composition described in <3> The compound of formula (I) is a hydroxylamine. <1> The composition described in <4> The compound of formula (I) is in an amount of about 0.01% to about 10% by weight of the composition. <1> The composition described in <5> The at least one unsaturated C 3 -C 12 The carboxylic acid includes acrylic acid, crotonic acid, 2-pentenoic acid, trans-2-hexenoic acid, fumaric acid, 10-undecenoic acid, 2-methyl-2-pentenoic acid, 2-pentenoic acid, 2-methyl-4-pentenoic acid, 2-octenoic acid, or 3-(2-furyl)acrylic acid. <1> The composition described in <6> The at least one unsaturated C 3 -C 12 The carboxylic acid is present in an amount of about 0.01% to about 3% by weight of the composition. <1> The composition described in <7> The at least one leveling agent comprises a sulfur-containing polymer or a nitrogen-containing polymer. <1> The composition described in <8> the at least one leveling agent comprises poly(4-styrenesulfonic acid), polyethyleneimine, polyglycine, poly(allylamine), polyaniline, sulfonated polyaniline, polyurea, polyacrylamide, poly(melamine-co-formaldehyde), polyaminoamide, or polyalkanolamine; <1> The composition described in <9> The at least one leveling agent is present in an amount of about 0.01% to about 3% by weight of the composition. <1> The composition described in <10> The water is in an amount of about 50% to about 99% by weight of the composition. <1> The composition described in <11> further comprising at least one Co etching accelerator. <1> The composition described in <12> The at least one Co etching accelerator comprises an acid selected from the group consisting of carboxylic acids or amino acids. <11> The composition described in <13> The at least one Co etching accelerator comprises citric acid, formic acid, acetic acid, oxalic acid, glycine, glycolic acid, malonic acid, lactic acid, or diethylenetriaminepentaacetic acid. <11> The composition described in <14> the at least one Co etching accelerator is in an amount of about 0.01% to about 3% by weight of the composition; <11> The composition described in <15> further comprising at least one pH adjuster. <1> The composition described in <16> The at least one pH adjusting agent comprises a base or an acid. <15> The composition described in <17> The base does not contain a metal ion and is not a quaternary ammonium hydroxide or an alkyl hydroxide, and the acid is not a saturated carboxylic acid or a hydrogen halide. <16> The composition described in <18> The at least one pH adjusting agent is present in an amount of about 0.01% to about 6% by weight of the composition. <15> The composition described in <19> The method further comprises the step of preparing a water-soluble organic solvent selected from the group consisting of water-soluble alcohols, water-soluble ketones, water-soluble esters, and water-soluble ethers. <1> The composition described in <20> The organic solvent is in an amount of about 0.5% to about 30% by weight of the composition. <19> The composition described in <21> The semiconductor substrate including the Co features is <1> and removing at least a portion of the Co features. <22> The method further comprises rinsing the semiconductor substrate with a rinsing solvent after the contacting step. <21> The method according to <23> The method further comprises drying the semiconductor substrate after the rinsing step. <22> The method according to <24> The method does not substantially form a cobalt oxide hydroxide layer on the semiconductor substrate. <21> The method according to <25> The semiconductor device <21> 2. An article formed by the method of claim 1. <26> The semiconductor device is an integrated circuit. <25> The article described in

Claims

1. 1) Formula (I): R １ -O-N-R ２ R ３ In the above formula (I), R １ , R ２ and R ３ each independently is H or C １ -C ６ is an alkyl group; 2) at least one unsaturated C ３ -C １２ Carboxylic acid; 3) at least one leveling agent comprising a sulfur-containing polymer or a nitrogen-containing polymer; and 4) water, 1. An etching composition for etching cobalt comprising:

2. The composition of claim 1 , wherein the composition has a pH of from 0 to 7.

3. The composition of claim 1 , wherein the compound of formula (I) is a hydroxylamine.

4. The composition of claim 1, wherein the compound of formula (I) is in an amount of 0.01% to 10% by weight of the composition.

5. The at least one unsaturated C ３ -C １２ 2. The composition of claim 1, wherein the carboxylic acid comprises acrylic acid, crotonic acid, 2-pentenoic acid, trans-2-hexenoic acid, fumaric acid, 10-undecenoic acid, 2-methyl-2-pentenoic acid, 2-pentenoic acid, 2-methyl-4-pentenoic acid, 2-octenoic acid, or 3-(2-furyl)acrylic acid.

6. The at least one unsaturated C ３ -C １２ The composition of claim 1, wherein the carboxylic acid is in an amount of from 0.01% to 3% by weight of the composition.

7. 2. The composition of claim 1, wherein the at least one leveling agent comprises poly(4-styrenesulfonic acid), polyethyleneimine, polyglycine, poly(allylamine), polyaniline, sulfonated polyaniline, polyurea, polyacrylamide, poly(melamine-co-formaldehyde), polyaminoamide, or polyalkanolamine.

8. The composition of claim 1, wherein the at least one leveling agent is in an amount of from 0.01% to 3% by weight of the composition.

9. The composition of claim 1, wherein the water is in an amount of from 50% to 99% by weight of the composition.

10. The composition of claim 1 further comprising at least one Co etch accelerator.

11. 11. The composition of claim 10, wherein the at least one Co etch accelerator comprises an acid selected from the group consisting of a carboxylic acid or an amino acid.

12. 11. The composition of claim 10, wherein the at least one Co etch accelerator comprises citric acid, formic acid, acetic acid, oxalic acid, glycine, glycolic acid, malonic acid, lactic acid, or diethylenetriaminepentaacetic acid.

13. The composition of claim 10, wherein the at least one Co etch accelerator is in an amount of 0.01% to 3% by weight of the composition.

14. The composition of claim 1 further comprising at least one pH adjuster.

15. The composition of claim 14 , wherein the at least one pH adjuster comprises a base or an acid.

16. 16. The composition of claim 15, wherein the base does not contain a metal ion and is not a quaternary ammonium hydroxide and the acid is not a saturated carboxylic acid or a hydrogen halide.

17. The composition of claim 14, wherein the at least one pH adjusting agent is in an amount of from 0.01% to 6% by weight of the composition.

18. 10. The composition of claim 1, further comprising an organic solvent selected from the group consisting of water-soluble alcohols, water-soluble ketones, water-soluble esters, and water-soluble ethers.

19. 19. The composition of claim 18, wherein the organic solvent is in an amount of from 0.5% to 30% by weight of the composition.

20. 13. A method comprising contacting a semiconductor substrate including Co features with the composition of claim 1 and removing at least a portion of the Co features.

21. 21. The method of claim 20, further comprising rinsing the semiconductor substrate with a rinsing solvent after the contacting step.

22. 22. The method of claim 21, further comprising drying the semiconductor substrate after the rinsing step.

23. 21. The method of claim 20, wherein the method does not substantially form a cobalt oxide hydroxide layer on the semiconductor substrate.

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