Etching Composition

Abstract

The present disclosure relates to an etching composition which, for example, can be used to selectively remove silicon germanium (SiGe) from a semiconductor substrate as an intermediate step in a multi-step semiconductor manufacturing process.

Description

Cross-reference to related applications

[0001] This application claims priority to U.S. Provisional Application No. 63 / 546,795, filed November 1, 2023, the contents of which are incorporated herein by reference in their entirety. Technical Field

[0002] This disclosure relates to etching compositions and methods of using etching compositions. In particular, this disclosure relates to etching compositions that can selectively etch silicon-germanium in the presence of other exposed or underlying materials such as metallic conductors (e.g., copper), barrier materials, insulating materials (e.g., low-k dielectric materials). Background Technology

[0003] The semiconductor industry is rapidly shrinking the size and increasing the density of electronic circuits and components in microelectronic devices, silicon chips, liquid crystal displays, MEMS (microelectromechanical systems), and printed circuit boards. Integrated circuits are being layered or stacked, with the thickness of the insulating layers between circuit layers continuously decreasing, resulting in increasingly smaller volumetric dimensions. As volumetric dimensions shrink, patterns become smaller, and device performance parameters become more stringent and robust. Consequently, due to the smaller volumetric dimensions, various problems that were previously tolerable become intolerable or escalate into more significant issues.

[0004] In advanced integrated circuit manufacturing, high-k and low-k insulators and various barrier layer materials have been used to minimize problems related to higher density and optimize performance.

[0005] Silicon germanium (SiGe) can be used to manufacture semiconductor devices, liquid crystal displays, MEMS (microelectromechanical systems), printed circuit boards, etc., as nanowires and / or nanosheets. For example, it can be used as the gate material in multi-gate devices, such as multi-gate field-effect transistors (FETs) (e.g., all-around gate FETs). Summary of the Invention

[0006] In the fabrication of semiconductor devices, etching silicon germanium (SiGe) is frequently required. In the various applications and device environments of SiGe, other layers may come into contact with or be otherwise exposed to it during etching. In the presence of these other materials (e.g., metallic conductors, dielectrics, and hard masks), highly selective etching of SiGe is typically required to achieve device yield and long lifespan. SiGe etching can be performed using plasma etching. However, using plasma etching on SiGe layers can damage either or both of the gate insulating layer and the semiconductor substrate. Furthermore, the etching process can remove a portion of the semiconductor substrate by etching the gate insulating layer exposed by the gate electrode. The electrical characteristics of the transistor can be negatively affected. To avoid such etching damage, additional protective manufacturing steps can be employed, but these are costly.

[0007] This disclosure relates to compositions and methods for selectively etching SiGe relative to a hard mask layer, a gate material (e.g., SiN, poly-Si, or SiOx), and a low-k dielectric layer (e.g., SiN, poly-Si, SiOx, carbon-doped oxide, or SiCO) present in a semiconductor device. More specifically, this disclosure relates to compositions and methods for selectively etching SiGe relative to a low-k dielectric layer.

[0008] In some embodiments, this disclosure provides an etching composition comprising: At least one fluorinated acid, including hydrofluoric acid or hexafluorosilicic acid; At least one oxidizing agent; At least one organic acid or an anhydride of said at least one organic acid, or a combination thereof; At least one silicon-containing compound; and water.

[0009] In some embodiments, the at least one fluorinated acid accounts for about 0.01 wt% to about 2 wt% of the composition.

[0010] In some embodiments, the at least one oxidant comprises hydrogen peroxide or peracetic acid. In some embodiments, the at least one oxidant accounts for about 5 wt% to about 10 wt% of the composition.

[0011] In some embodiments, the at least one organic acid includes formic acid, acetic acid, propionic acid, or butyric acid. In some embodiments, the anhydride of the at least one organic acid includes formic anhydride, acetic anhydride, propionic anhydride, or butyric anhydride. In some embodiments, the composition includes an organic acid and its anhydride. In some embodiments, the organic acid is acetic acid and the anhydride is acetic anhydride. In some embodiments, the at least one organic acid accounts for about 10 wt% to about 30 wt% of the composition, and the anhydride of the at least one organic acid accounts for about 40 wt% to about 70 wt% of the composition.

[0012] In some embodiments, the silicon-containing compound comprises a siloxane or a silazane. In some embodiments, the silicon-containing compound is a tetraethoxysilane, triethoxymethylsilane, hexamethyldisilazane, or tetramethyldisilazane. In some embodiments, the silicon-containing compound is a silane-modified polymer. In some embodiments, the silane-modified polymer comprises a silane-modified olefin polymer. In some embodiments, the silane-modified olefin polymer is polyethylene, polypropylene, polybutadiene, polyisoprene, polystyrene, or copolymers thereof. In some embodiments, the silane-modified polymer comprises polybutadiene. In some embodiments, the silane-modified polymer comprises at least one trialkoxysilyl moiety. In some embodiments, each alkoxy moiety is independently C1-C5 alkoxy.

[0013] In some embodiments, the water comprises about 5 wt% to about 30 wt% of the composition.

[0014] In some embodiments, the etching composition disclosed herein further includes at least one polymerized naphthalene sulfonic acid. In some embodiments, the at least one polymerized naphthalene sulfonic acid comprises a sulfonic acid having the following structure: , Where n is between 3 and 6.

[0015] In some embodiments, the at least one polymerized naphthalenesulfonic acid accounts for about 0.005 wt% to about 0.15 wt% of the composition.

[0016] In some embodiments, the etching composition disclosed herein further comprises at least one amine, including amines of formula (I): N-R1R2R3, wherein R1 is a C1-C8 alkyl group optionally substituted with OH or NH2, R2 is a C1-C8 alkyl group optionally substituted with H or OH, and R3 is a C1-C8 alkyl group optionally substituted with OH. In some embodiments, the amine of formula (I) is diisopropylamine, N-butyldiethanolamine, N-(3-aminopropyl)-diethanolamine, N-octylglucosamine, N-ethylglucosamine, N-methylglucosamine, or 1-[bis(2-hydroxyethyl)amino]-2-propanol. In some embodiments, the at least one amine is present in an amount from about 0.001 wt% to about 0.15 wt% of the composition.

[0017] In some embodiments, the etching composition disclosed herein further includes an inorganic acid. In some embodiments, the inorganic acid is sulfuric acid, nitric acid, or phosphoric acid.

[0018] In some embodiments, the etching composition disclosed herein has a pH of less than 1.

[0019] In some embodiments, this disclosure provides a method comprising: A semiconductor substrate containing a SiGe film is brought into contact with the composition disclosed herein to substantially remove the SiGe film. In some embodiments, the SiGe film comprises about 10 wt% to about 30 wt% Ge.

[0020] In some embodiments, the method of this disclosure further includes rinsing the semiconductor substrate with a rinsing solvent after the contact step. In some embodiments, the method of this disclosure further includes drying the semiconductor substrate after the rinsing step.

[0021] In some embodiments, the methods disclosed herein do not substantially remove SiN, polycrystalline Si, or SiCO.

[0022] In some embodiments, this disclosure provides an article of manufacture formed by the methods of this disclosure, wherein the article of manufacture is a semiconductor device. In some embodiments, the semiconductor device is an integrated circuit. Detailed Implementation

[0023] As defined herein, unless otherwise specified, all percentages expressed shall be understood as weight percentages of the total weight of the composition. Unless otherwise specified, ambient temperature is defined as between about 16 and about 27 degrees Celsius (°C).

[0024] Generally, this disclosure is characterized by an etching composition (e.g., an etching composition for selective removal of SiGe) comprising at least one fluorinated acid, including hydrofluoric acid or hexafluorosilicic acid. At least one oxidizing agent; At least one organic acid or an anhydride of said at least one organic acid, or a combination thereof; At least one silicon-containing compound; and water.

[0025] Generally, the etching compositions disclosed herein may include at least one (e.g., two, three, or four) fluorinated agents. The fluorinated acids described herein may be inorganic acids, such as HF or H2SiF6. In some embodiments, the at least one fluorescent acid comprises at least about 0.01 wt% (e.g., at least about 0.02 wt%, at least about 0.03 wt%, at least about 0.04 wt%, at least about 0.05 wt%, at least about 0.1 wt%, at least about 0.2 wt%, at least about 0.4 wt%, at least about 0.5 wt%, at least about 0.6 wt%, at least about 0.8 wt%, at least about 1 wt%, at least about 1.2 wt%, at least about 1.4 wt%, or at least about 1.5 wt%) to at most about 2 wt% (e.g., at most about 1.9 wt%, at most about 1.8 wt%, at most about 1.7 wt%, at most about 1.6 wt%, at most about 1.5 wt%, at most about 1.2 wt%, at most about 1 wt%, or at most about 0.5 wt%) of the etch composition disclosed herein. It is not intended to be limited by theory, but it is believed that the fluorescent acid can promote and enhance the removal of SiGe from the semiconductor substrate during the etching process.

[0026] The etching compositions disclosed herein may include at least one (e.g., two, three, or four) oxidants suitable for microelectronic applications. Examples of suitable oxidants include, but are not limited to, oxidizing acids or salts thereof (e.g., nitric acid, permanganic acid, or potassium permanganate), peroxides (e.g., hydrogen peroxide, dialkyl peroxide, urea hydrogen peroxide), persulfonic acids (e.g., hexafluoropropane persulfonic acid, methane persulfonic acid, trifluoromethane persulfonic acid, or p-toluene persulfonic acid) and their salts, ozone, peroxycarboxylic acids (e.g., peracetic acid) and their salts, superphosphate and their salts, persulfate and their salts (e.g., ammonium persulfate or tetramethylammonium persulfate), perchloric acid and its salts (e.g., ammonium perchlorate, sodium perchlorate, or tetramethylammonium perchlorate), and periodic acid and its salts (e.g., periodic acid, ammonium periodate, or tetramethylammonium periodate). These oxidants may be used alone or in combination.

[0027] In some embodiments, the at least one oxidant may comprise at least about 5% by weight (e.g., at least about 6% by weight, at least about 7% by weight, at least about 8% by weight, at least about 9% by weight, at least about 10% by weight, at least about 11% by weight, at least about 13% by weight, or at least about 15% by weight) to at most about 20% by weight (e.g., at most about 18% by weight, at most about 16% by weight, at most about 15% by weight, at most about 14% by weight, at most about 12% by weight, or at most about 10% by weight) of the etch composition disclosed herein. Not wishing to be limited by theory, it is believed that the oxidant can promote and enhance the removal of SiGe from the semiconductor substrate.

[0028] Generally, the etching compositions of this disclosure may include at least one (e.g., two, three, or four) organic acids or their anhydrides. In some embodiments, the organic acid may be formic acid, acetic acid, propionic acid, or butyric acid. In some embodiments, the organic anhydride may be formic anhydride, acetic anhydride, propionic anhydride, or butyric anhydride. In some embodiments, the at least one organic acid may account for at least about 10 wt% (e.g., at least about 15 wt%, at least about 20 wt%, at least about 25 wt%, at least about 30 wt%, or at least about 35 wt%) to at most about 40 wt% (e.g., at most about 35 wt%, at most about 30 wt%, at most about 25 wt%, at most about 20 wt%, or at most about 15 wt%) of the etching composition of this disclosure. In some embodiments, the anhydride of at least one organic acid may comprise at least 30% by weight (e.g., at least 35% by weight, at least 40% by weight, at least 45% by weight, at least 50% by weight, at least 55% by weight, or at least 60% by weight) to at most 90% by weight (e.g., at most 85% by weight, at most 80% by weight, at most 75% by weight, at most 70% by weight, at most 65% by weight, at most 60% by weight, at most 55% by weight, at most 50% by weight, at most 45% by weight, or at most 40% by weight) of the etching composition disclosed herein. It is not intended to be limited by theory, but it is believed that the organic acid or its anhydride can promote and enhance the removal of SiGe from the semiconductor substrate.

[0029] The etching compositions disclosed herein may typically include at least one polymerized naphthalenesulfonic acid (or poly(naphthalenesulfonic acid)), for example, as a surfactant or selective inhibitor. In some embodiments, the polymerized naphthalenesulfonic acid may be a sulfonic acid having the following chemical structure: , Where n is 3, 4, 5, or 6. Commercially available examples of such polymerized naphthalene sulfonic acids include the Takesurf A-47 series products available from Takemoto Oil & Fat Co., Ltd. In some embodiments, the at least one polymerized naphthalene sulfonic acid may comprise at least about 0.005% by weight (e.g., at least about 0.01% by weight, at least about 0.02% by weight, at least about 0.03% by weight, at least about 0.04% by weight, at least about 0.05% by weight, or at least about 0.1% by weight) to at most about 0.15% by weight (e.g., at most about 0.14% by weight, at most about 0.12% by weight, at most about 0.1% by weight, at most about 0.08% by weight, at most about 0.06% by weight, or at most about 0.05% by weight) of the etch composition of this disclosure. It is not intended to be theoretically limited, but it is believed that when removing SiGe from a semiconductor substrate using the etch composition of this disclosure, the polymerized naphthalene sulfonic acid may selectively inhibit the removal of SiN, polycrystalline Si, and SiCO.

[0030] Generally, the etching compositions disclosed herein may include at least one (e.g., two, three, or four) amines. In some embodiments, the amine may be an amine of formula (I): N-R1R2R3, wherein R1 is a C1-C8 alkyl group optionally substituted with OH or NH2, R2 is a C1-C8 alkyl group optionally substituted with H or OH, and R3 is a C1-C8 alkyl group optionally substituted with OH. Examples of suitable amines of formula (I) include diisopropylamine, N-butyldiethanolamine, N-(3-aminopropyl)-diethanolamine, N-octylglucosamine, N-ethylglucosamine, N-methylglucosamine, and 1-[bis(2-hydroxyethyl)amino]-2-propanol.

[0031] In some embodiments, the at least one amine may comprise at least about 0.001 wt% (e.g., at least about 0.002 wt%, at least about 0.005 wt%, at least about 0.008 wt%, at least about 0.01 wt%, at least about 0.02 wt%, at least about 0.05 wt%, or at least about 0.1 wt%) to at most about 0.15 wt% (e.g., at most about 0.14 wt%, at most about 0.12 wt%, at most about 0.1 wt%, at most about 0.08 wt%, at most about 0.06 wt%, or at most about 0.05 wt%) of the etch composition of this disclosure. It is not intended to be theoretically limited, but it is believed that the amine may selectively inhibit the removal of SiN, polycrystalline Si, and SiCO when removing SiGe from a semiconductor substrate using the etch composition of this disclosure.

[0032] In some embodiments, the etching composition disclosed herein includes at least one silicon-containing compound. In some embodiments, the silicon-containing compound includes a siloxane or a silazane. In some embodiments, the silicon-containing compound is tetraethoxysilane, triethoxymethylsilane, hexamethyldisilazane, or tetramethyldisilazane.

[0033] Other examples of silicon-containing compounds contemplated for use in the compositions of this disclosure include, but are not limited to, hexamethyldisiloxane, 1,3-diphenyl-1,3-dimethyldisiloxane, 1,1,3,3-tetramethyldisiloxane, 1,1,1-triethyl-3,3-dimethyldisiloxane, 1,1,3,3-tetra-n-octyldimethyldisiloxane, bis(nonafluorohexyl)tetramethyldisiloxane, 1,3-bis(trifluoropropyl)tetramethyldisiloxane, 1,3-di-n-butyltetramethyldisiloxane, 1,3-di-n-octyltetramethyldisiloxane, 1,3-diethyltetramethyldisiloxane, 1,3-diphenyltetramethyldisiloxane, hexa-n-butyldisiloxane, hexaethyldisiloxane, hexavinyldisiloxane, 1,1,1,3, 3-Pentamethyl-3-acetoxydisiloxane, 1-Allyl-1,1,3,3-Tetramethyldisiloxane, 1,3-bis(3-aminopropyl)tetramethyldisiloxane, 1,3-bis(heptadecanofluoro-1,1,2,2-tetrahydrodecyl)tetramethyldisiloxane, 1,3-Divinyltetraphenyldisiloxane, 1,3-Divinyltetramethyldisiloxane, 1,3-Diallyltetra(trimethylsiloxy)disiloxane, 1,3-Diallyltetramethyldisiloxane, 1,3-Diphenyltetra(dimethylsiloxy)disiloxane, (3-chloropropyl)pentamethyldisiloxane, 1,3-Divinyltetra(trimethylsiloxy)disiloxane, 1,1,3,3-tetraisopropyldisiloxane, 1,1,3,3-tetravinyldimethyl 1,1,3,3-Tetracyclopentyldichlorodisiloxane, vinylpentamethyldisiloxane, 1,3-bis(3-chloroisobutyl)tetramethyldisiloxane, hexaphenyldisiloxane, 1,3-bis[(bicyclo[2.2.1]hept-2-enyl)ethyl]tetramethyldisiloxane, 1,1,1-triethyl-3,3,3-trimethyldisiloxane, 1,3-bis(3-methacryloyloxypropyl)tetramethyldisiloxane, 1,3-bis(chloromethyl)tetramethyldisiloxane, 1,1,3,3-tetramethyl-1,3-diethoxydisiloxane, 1,1,3,3-tetraphenyldimethyldisiloxane, methacryloyloxypentamethyldisiloxane, pentamethyldisiloxane, 1,3-bis(3-chloropropyl)tetramethyldisiloxane Siloxanes, 1,3-bis(4-hydroxybutyl)tetramethyldisiloxane, 1,3-bis(triethoxysilylethyl)tetramethyldisiloxane, 3-aminopropylpentamethyldisiloxane, 1,3-bis(2-aminoethylaminomethyl)tetramethyldisiloxane, 1,3-bis(3-carboxypropyl)tetramethyldisiloxane, 1,3-dichloro-1,3-diphenyl-1,3-dimethyldisiloxane, 1,3-diethynyltetramethyldisiloxane, n-butyl-1,1,3,3-tetramethyldisiloxane, 1,3-dichlorotetraphenyldisiloxane, 1,3-dichlorotetramethyldisiloxane, 1,3-di-tert-butyldisiloxane, 1,3-dimethyltetramethoxydisiloxane, 1,3-divinyltetraethoxydisiloxane, 1,1,3,3-Tetraethoxy-1,3-dimethyldisiloxane, vinyl-1,1,3,3-tetramethyldisiloxane, platinum-[1,3-bis(cyclohexyl)imidazol-2-yl][hexachlorodisiloxane], 1,1,3,3-tetraisopropyl-1-chlorodisiloxane, 1,1,1-trimethyl-3,3,3-triphenyldisiloxane, 1,3-bis(trimethylsiloxy)-1,3-dimethyldisiloxane, 3,3-diphenyltetramethyltrisiloxane, 3-phenylheptamethyltrisiloxane, hexamethylcyclotrisiloxane, n-propylheptamethyltrisiloxane, 1,5-diethoxyhexamethyltrisiloxane, 3-ethylheptamethyltrisiloxane, 3-(tetrahydrofurfuryloxypropyl)heptamethyltrisiloxane, 3-(3,3,3-trifluoro 3-(3-acetoxypropyl)heptamethyltrisiloxane, 1,1,3,5,5-pentaphenyl-1,3,5-trimethyltrisiloxane, octamethyltrisiloxane, 1,1,5,5-tetraphenyl-1,3,3,5-tetramethyltrisiloxane, hexaphenylcyclotrisiloxane, 1,1,1,5,5,5-hexamethyltrisiloxane, octachlorotrisiloxane, 3-phenyl-1,1,3,5,5-pentamethyltrisiloxane, (3,3,3-trifluoropropyl)methylcyclotrisiloxane, 1,3,5-trivinyl-1,1,3,5,5-pentamethyltrisiloxane, 1,3,5-trivinyl-1,3,5-trimethylcyclotrisiloxane, 3-(3-acetoxypropyl)heptamethyltrisiloxane, 3-(m-pentadecanylphenoxypropyl))heptamethyl Trisiloxane, limonenyltrisiloxane, 3-dodecylheptamethyltrisiloxane, 3-octylheptamethyltrisiloxane, 1,3,5-triphenyltrimethylcyclotrisiloxane, 1,1,1,3,3,5,5-heptamethyltrisiloxane, 1,1,3,3,5,5-hexamethyltrisiloxane, 1,1,1,5,5,5-hexaethyl-3-methyltrisiloxane, 1,5-dichlorohexamethyltrisiloxane, 3-trianetraalkylheptamethyltrisiloxane, 3-(3-hydroxypropyl)heptamethyltrisiloxane, hexamethylcyclomethylphosphonotrisiloxane, 3-octadecylheptamethyltrisiloxane, furfuryloxytrisiloxane, tetra(dimethylsiloxy)silane, 1,1,3,3,5,5,7,7-octamethyltetrasiloxane, diphenyl 1,3-Diphenyl-1,3-dimethyldisiloxane copolymer, octamethylcyclotetrasiloxane, 1,3-bis(trimethylsiloxy)-1,3-dimethyldisiloxane, dimethylsiloxane-[65-70% (60% propylene oxide / 40% ethylene oxide) block copolymer], bis(hydroxypropyl)tetramethyldisiloxane, tetra-n-propyltetramethylcyclotetrasiloxane, octaethylcyclotetrasiloxane, decamethyltetrasiloxane, dodecylcyclohexasiloxane, dodecylpentasiloxane, tetradecamethylhexasiloxane, hexaphenylcyclotrisiloxane, polydimethylsiloxane, polyoctadecylmethylsiloxane, hexadecyl-terminated polydimethylsiloxane, decamethylcyclopentasiloxane, poly(3,3,3-Trifluoropropylmethylsiloxane), trimethylsiloxy-terminated polydimethylsiloxane, 1,1,3,3,5,5,7,7,9,9-decamethylpentasiloxane, or triethylsiloxy-terminated polydiethylsiloxane.

[0034] In some embodiments, the silicon-containing compound is a silane-modified polymer. In some embodiments, the silane-modified polymer is a silane-modified olefin polymer. Contemplated silane-modified olefin polymers include, but are not limited to, polyethylene, polypropylene, polybutadiene, polyisoprene, polystyrene, or copolymers thereof. In some embodiments, the silane-modified polymer includes polybutadiene.

[0035] In some embodiments, the silane-modified polymer comprises at least one trialkoxysilane moiety. In some embodiments, each alkoxy moiety is independently C1-C5 alkoxy.

[0036] In some embodiments, the silicon-containing compound is present in the compositions disclosed herein in an amount of about 0.005 wt% to about 0.250 wt%.

[0037] Generally, the etching compositions of this disclosure 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 water comprises an amount from at least about 5 wt% (e.g., at least about 7 wt%, at least about 10 wt%, at least about 13 wt%, or at least about 15%) to at most about 30 wt% (e.g., at most about 29 wt%, at most about 27 wt%, or at most about 25 wt%) of the etching composition. It is not intended to be theoretically limited, but it is believed that if the amount of water exceeds 30 wt% of the composition, it will adversely affect the SiGe etching rate and reduce its removal during the etching process. On the other hand, it is not intended to be theoretically limited, but it is believed that the etching compositions of this disclosure should include a certain amount of water (e.g., at least about 5 wt%) to keep all other components dissolved and to avoid a reduction in etching performance.

[0038] In some embodiments, the etching composition disclosed herein further includes an inorganic acid. In some embodiments, the inorganic acid is sulfuric acid, nitric acid, or phosphoric acid.

[0039] In some embodiments, the etching composition disclosed herein may further include at least one (e.g., two, three, or four) organic solvents. In some embodiments, the at least one organic solvent may include an alcohol or an alkylene glycol ether. Examples of suitable organic solvents include propylene glycol, hexanediol, 1,3-propanediol, ethylene glycol butyl ether, and 3-methoxy-3-methyl-1-butanol. In some embodiments, the at least one organic solvent may comprise at least about 10 wt% (e.g., at least about 15 wt%, at least about 20 wt%, at least about 25 wt%, at least about 30 wt%, or at least about 35 wt%) to at most about 40 wt% (e.g., at most about 35 wt%, at most about 30 wt%, at most about 25 wt%, at most about 20 wt%, or at most about 15 wt%) of the etching composition.

[0040] Furthermore, in some embodiments, the etching compositions of this disclosure may contain additives, such as pH adjusters, corrosion inhibitors, surfactants, additional organic solvents, biocides, and defoamers as optional components. Examples of suitable additives include alcohols (e.g., polyvinyl alcohol), 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 ethynyl glycol ethoxylates (such as those described in U.S. Patent No. 6,717,019, which is incorporated herein by reference). Examples of suitable surfactants may be cationic, anionic, nonionic, or amphoteric.

[0041] Generally, the etching compositions of this disclosure may have relatively high SiGe / dielectric material (e.g., SiN, polysilicon, or SiCO) etch selectivity (i.e., a high ratio of SiGe etch rate to dielectric material etch rate). In some embodiments, the etching composition may have a SiGe / dielectric material etch selectivity of at least about 10 (e.g., at least about 15, at least about 20, at least about 25, at least about 30, at least about 35, at least about 40, at least about 45, at least about 50, at least about 55, at least about 60, at least about 65, at least about 70, or at least about 75) and / or up to about 500 (e.g., up to about 300, at most about 250, at most about 200, or at most about 100).

[0042] In some embodiments, the etching compositions disclosed herein may specifically exclude one or more of the additive components, or, if more than one, any combination of the additive components. These components are selected from the group consisting of: polymers, oxygen scavengers, quaternary ammonium salts (including quaternary ammonium hydroxides, such as TMAH), amines, basic bases (such as NaOH, KOH, and LiOH), surfactants other than defoamers, defoamers, fluorinated compounds, abrasives, silicates, hydroxycarboxylic acids containing more than two hydroxyl groups, carboxylic acids or polycarboxylic acids lacking an amino group, silanes (e.g., alkoxysilanes), cyclic compounds (e.g., azoles (such as diazoles, triazoles, or tetraazoles), triazines, and cyclic compounds containing at least two rings, such as substituted or unsubstituted naphthalenes, or substituted or unsubstituted biphenyl ethers), buffers, nonazole corrosion inhibitors, and metal salts (e.g., metal halides).

[0043] The etching composition disclosed herein can be prepared by simply mixing the components together, or by mixing two compositions in a kit. The first composition in the kit may be an aqueous solution of an oxidant (e.g., H2O2). The second composition in the kit may contain the remaining components of the etching composition disclosed herein in a concentrated form in a predetermined proportion, such that mixing the two compositions produces the desired etching composition disclosed herein.

[0044] In some embodiments, this disclosure features a method for etching a semiconductor substrate containing at least one SiGe film. The method may include contacting the semiconductor substrate containing at least one SiGe film with an etching composition of this disclosure to remove the SiGe film. In some embodiments, the method substantially removes the SiGe 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) 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., more than about 3% by weight or more than about 1% by weight) of metal conductors or dielectric materials from the semiconductor substrate.

[0045] In some embodiments, the SiGe film in the semiconductor substrate may comprise at least about 10 wt% (e.g., at least about 12 wt%, at least about 14 wt%, at least about 15 wt%, at least about 16 wt%, at least about 18 wt%, at least about 20 wt%) and / or up to about 35 wt% (e.g., up to about 34 wt%, up to about 32 wt%, up to about 30 wt%, up to about 28 wt%, up to about 26 wt%, up to about 25 wt%, up to about 24 wt%, up to about 22 wt%, up to about 20 wt%, up to about 18 wt%, up to about 16 wt%, or up to about 15 wt%) of Ge as a percentage of the SiGe film. Not wishing to be limited by theory, it is believed that SiGe films containing about 10 wt% to about 35 wt% Ge can be more easily removed from the semiconductor substrate by an etching composition compared to films containing more than 35 wt% or less than 10 wt% Ge.

[0046] In some embodiments, the etching method includes the following steps: (A) Providing a semiconductor substrate containing a SiGe film; (B) Contact the semiconductor substrate with the etching composition described herein; (C) Rinse the semiconductor substrate with one or more suitable rinsing solvents; and (D) The semiconductor substrate is dried, optionally (e.g., by any suitable means of removing the rinsing solvent without compromising the integrity of the semiconductor substrate).

[0047] In this method, the SiGe-containing semiconductor substrate to be etched may contain organic and inorganic metal residues, as well as a series of metal oxides, some or all of which may be removed during the etching process.

[0048] The semiconductor substrates (e.g., wafers) described herein are typically made of silicon, silicon germanium, group III-V compounds such as GaAs, or any combination thereof. The semiconductor substrate may additionally contain exposed integrated circuit structures, such as interconnect features (e.g., metal lines and dielectric materials). Metals and metal alloys used for interconnect features 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 contain the following layers: interlayer dielectric, polysilicon, silicon oxide, silicon nitride, silicon carbide, titanium oxide, and carbon-doped silicon oxide.

[0049] The semiconductor substrate can be brought 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.

[0050] The etch composition disclosed herein can be effectively used at temperatures up to about 85°C (e.g., about 20°C to about 80°C, about 55°C to about 65°C, or about 60°C to about 65°C). Within this temperature range, the etch rate of SiGe increases with increasing temperature, thus processes at higher temperatures can run for shorter times. Conversely, lower etch temperatures typically require longer etch times.

[0051] Etching times can vary widely depending on the specific etching method, thickness, and temperature used. When etching in an immersion batch process, suitable time ranges are, 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).

[0052] To further enhance the etching capability of the etching composition disclosed herein, mechanical agitation may be employed. Examples of suitable agitation methods include circulating the etching composition above the substrate during the etching process, flowing or spraying the etching composition onto the substrate, and agitation using ultrasound or megaphones. The semiconductor substrate can be oriented at any angle relative to the ground. Horizontal or vertical orientation is preferred.

[0053] Following the etching, the semiconductor substrate may be rinsed with a suitable rinsing solvent for approximately 5 seconds to approximately 5 minutes, with or without stirring. 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. Optionally or additionally, an aqueous rinsing solution with a pH > 8 (such as a dilute aqueous solution of ammonium hydroxide) may be used. Examples of rinsing solvents include, but are not limited to, dilute aqueous solution of ammonium hydroxide, DI water, methanol, ethanol, and isopropanol. The rinsing solvent may be applied using a similar method to that used when 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.

[0054] 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 such as a heating plate or infrared lamp, Maragoni drying, rotagoni drying, IPA drying, or any combination thereof. The drying time will depend on the specific method used, but is typically from 30 seconds to at most a few minutes.

[0055] In some embodiments, the etching method described herein further includes forming a semiconductor device (e.g., an integrated circuit device, such as a semiconductor chip) from a semiconductor substrate obtained by the above method.

[0056] The present disclosure is described in more detail with reference to the following embodiments, which are for illustrative purposes and should not be construed as limiting the scope of the disclosure.

[0057] Example Unless otherwise specified, all percentages listed are by weight (wt%). Unless otherwise stated, controlled stirring during testing was performed with a 1-inch stir bar at 300 rpm.

[0058] General Procedure 1 Formulation Mixing While stirring, add the remaining components of the formulation to the calculated amount of solvent to prepare a sample of the etching composition. After obtaining a homogeneous solution, add any optional additives (if used).

[0059] General Procedure 2 Materials and Methods Commercially available unpatterned 300 mm diameter wafers were used, cut into 0.5” x 1.0” test pieces for evaluation, to measure the etching rate of the blanket film on the film. The main blanket film materials used for testing included: 1) a SiGe film with a thickness of approximately 500 Å deposited on a silicon substrate; 2) a polycrystalline silicon film with a thickness of approximately 1000 Å deposited on a silicon substrate; and 3) a SiOx film with a thickness of approximately 1200 Å deposited on a silicon substrate.

[0060] The thickness of the blanket-coated test specimens before and after treatment was measured to determine the blanket-coated etching rate. For SiGe, SiOx, and polycrystalline silicon blanket coatings, the film thickness before and after treatment was measured using ellipsometry with Woollam VASE.

[0061] Material compatibility and / or etching response were evaluated on patterned SiGe (3 nm) / Si test specimens. The treated test specimens were then evaluated using scanning electron microscopy (SEM). SEM images of the treated specimens were compared with previously obtained pre-treated SEM image sets to assess the material compatibility and etching response of each test formulation with the patterned test device morphology.

[0062] General Procedure 3 Etching assessment using beaker testing At room temperature (25) o C) All blanket-coated etching tests were performed in 200 mL PFA vials containing 100 g of sample solution, with the solution continuously stirred at 250 rpm. All blanket-coated 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 dicing tool for beaker-scale testing. Each individual test piece was held in place using a single 4” long locking plastic tweezer. The test piece, held in place with one side locked by the tweezer, was suspended in the 200 mL PFA vial and immersed in 100 g of test solution, while being kept at room temperature (25°C). o C) Stir the solution continuously at 250 rpm. Keep the test piece still in the stirred solution until the treatment time has elapsed (as described in General Procedure 3A). After the treatment time in the test solution has elapsed, immediately remove the sample test piece from the 200 mL PFA bottle and rinse according to General Procedure 3A. Following the final DIW rinsing step, use a handheld nitrogen blower to purge all test pieces with filtered nitrogen to forcefully remove all trace amounts of DIW, producing the final dry sample for test measurements.

[0063] Standard Procedure 3A (Blanket Test Piece) After the 2 to 10-minute treatment time according to general procedure 3, immediately immerse the sample in 300 mL of ultrapure deionized (DI) water for 15 seconds with gentle agitation, then immerse it in 300 mL of DI water for 15 seconds with gentle agitation, and finally rinse it in flowing DIW for 15 seconds. Complete the treatment according to general procedure 3.

[0064] Example 1 Formulation examples 1-3 (FE-1 to FE-3) were prepared according to general procedure 1 and evaluated according to general procedures 2 and 3A. The formulations and test results are summarized in Table 1.

[0065] Table 1 Si-1 = Polybutadiene with pendant trialkoxysilane and pendant vinyl moieties Si-2 = Polybutadiene with a side-chain trialkoxysilane moiety Si-3 = Polybutadiene with side-chain trialkoxysilane and side-chain maleic anhydride moieties. APDA = N-(3-aminopropyl)-diethanolamine SiGe25 = SiGe film containing 25wt% Ge ER = Etching Rate As shown in Table 1, FE-1 to FE-3 exhibit a significant increase in SiGe25 / SiO selectivity compared to CFE-1. In other words, these formulations can effectively remove the SiGe film while minimizing the removal of SiO exposed on the semiconductor substrate during the etching process.

[0066] Although this disclosure has been described in detail with reference to certain embodiments thereof, it should be understood that modifications and variations fall within the spirit and scope of the description and claims.

Claims

1. An etching composition comprising: At least one fluorinated acid, wherein the at least one fluorinated acid comprises hydrofluoric acid or hexafluorosilicic acid; At least one oxidizing agent; At least one organic acid or an anhydride of said at least one organic acid, or a combination thereof; At least one silicon-containing compound; and water.

2. The composition of claim 1, wherein the at least one fluorinated acid accounts for about 0.01 wt% to about 2 wt% of the composition.

3. The composition of claim 1, wherein the at least one oxidant comprises hydrogen peroxide or peracetic acid.

4. The composition of claim 1, wherein the at least one oxidant accounts for about 5 wt% to about 10 wt% of the composition.

5. The composition of claim 1, wherein the at least one organic acid comprises formic acid, acetic acid, propionic acid or butyric acid.

6. The composition of claim 1, wherein the anhydride of the at least one organic acid comprises formic anhydride, acetic anhydride, propionic anhydride or butyric anhydride.

7. The composition of claim 1, wherein the composition comprises an organic acid and its anhydride.

8. The composition of claim 7, wherein the organic acid is acetic acid and the acid anhydride is acetic anhydride.

9. The composition of claim 1, wherein the at least one organic acid accounts for about 10 wt% to about 30 wt% of the composition.

10. The composition of claim 1, wherein the anhydride of the at least one organic acid accounts for about 40 wt% to about 70 wt% of the composition.

11. The composition of claim 1, wherein the water comprises about 5 wt% to about 30 wt% of the composition.

12. The composition of claim 1, wherein the silicon-containing compound comprises a siloxane or a silazane.

13. The composition of claim 12, wherein the silicon-containing compound is tetraethoxysilane, triethoxymethylsilane, hexamethyldisilazane, or tetramethyldisilazane.

14. The composition of claim 1, wherein the silicon-containing compound is a silane-modified polymer.

15. The composition of claim 14, wherein the silane-modified polymer comprises a silane-modified olefin polymer.

16. The composition of claim 15, wherein the silane-modified olefin polymer is polyethylene, polypropylene, polybutadiene, polyisoprene, polystyrene, or a copolymer thereof.

17. The composition of claim 16, wherein the silane-modified olefin polymer comprises polybutadiene.

18. The composition of claim 14, wherein the silane-modified polymer comprises at least one trialkoxysilane moiety.

19. The composition of claim 18, wherein each alkoxy moiety is independently C1-C5 alkoxy.

20. The composition of claim 1, further comprising at least one polymerized naphthalenesulfonic acid.

21. The composition of claim 20, wherein the at least one polymerized naphthalenesulfonic acid comprises a sulfonic acid having the following structure: ， Where n is between 3 and 6.

22. The composition of claim 20, wherein the at least one polymerized naphthalenesulfonic acid accounts for about 0.005 wt% to about 0.15 wt% of the composition.

23. The composition of claim 1 further comprises at least one amine comprising an amine of formula (I): N-R1R2R3, wherein R1 is a C1-C8 alkyl group optionally substituted with OH or NH2, R2 is a C1-C8 alkyl group optionally substituted with H or OH, and R3 is a C1-C8 alkyl group optionally substituted with OH.

24. The composition of claim 23, wherein the amine of formula (I) is diisopropylamine, N-butyldiethanolamine, N-(3-aminopropyl)-diethanolamine, N-octylglucosamine, N-ethylglucosamine, N-methylglucosamine or 1-[bis(2-hydroxyethyl)amino]-2-propanol.

25. The composition of claim 23, wherein the at least one amine is present in an amount of about 0.001 wt% to about 0.15 wt% of the composition.

26. The composition of claim 1, further comprising an inorganic acid.

27. The composition of claim 26, wherein the inorganic acid is sulfuric acid, nitric acid, or phosphoric acid.

28. The composition of claim 1, wherein the composition has a pH of less than 1.

29. A method comprising: The semiconductor substrate containing the SiGe film is brought into contact with the composition as described in claim 1 to substantially remove the SiGe film.

30. The method of claim 29, wherein the SiGe film comprises about 10 wt% to about 30 wt% Ge.

31. The method of claim 29, further comprising rinsing the semiconductor substrate with a rinsing solvent after the contact step.

32. The method of claim 31, further comprising drying the semiconductor substrate after the rinsing step.

33. The method of claim 29, wherein the method substantially does not remove SiN, polycrystalline Si, or SiCO.

34. An article of manufacture formed by the method of claim 29, wherein the article of manufacture is a semiconductor device.

35. The article of manufacture as claimed in claim 34, wherein the semiconductor device is an integrated circuit.

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