Etching Composition

Abstract

The present disclosure relates to etching compositions useful for selectively removing silicon germanium (SiGe) from semiconductor substrates, for example, as an intermediate step in a multi-step semiconductor manufacturing process.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Provisional Application No. 63 / 254,625, filed October 12, 2021, the contents of which are incorporated herein by reference in their entirety.

[0002] The present disclosure relates to etching compositions and processes using the etching compositions. In particular, the present disclosure relates to etching compositions that can selectively etch silicon germanium in the presence of other exposed or underlying materials, such as metal conductors (e.g., copper), barrier materials, insulator materials (e.g., low-k dielectric materials), etc. [Background technology]

[0003] The semiconductor industry is rapidly shrinking the dimensions and densifying electronic circuits and components, such as microelectronic devices, silicon chips, liquid crystal displays, MEMS (Micro Electro Mechanical Systems), printed wiring boards, etc. The integrated circuits therein are layered and stacked with ever-decreasing thicknesses of insulating layers between each circuit layer and smaller and smaller feature sizes. As feature sizes shrink, patterns become smaller and device performance parameters become tighter and more robust. As a result, various problems that were previously tolerated are no longer tolerated or become more problematic due to the smaller feature sizes.

[0004] In the manufacture of advanced integrated circuits, both high and low dielectric constant insulators and a variety of barrier layer materials have been used to minimize problems associated with high density and optimize performance.

[0005] Silicon germanium (SiGe), as nanowires and / or nanosheets, can be utilized in the manufacture of semiconductor devices, liquid crystal displays, MEMS (Micro Electro Mechanical Systems), printed wiring boards, etc. For example, it can be used as a 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 construction of semiconductor devices, silicon germanium (SiGe) must frequently be etched. In various types of uses and device environments for SiGe, other layers are contacted or otherwise exposed at the same time that this material is etched. Highly selective etching of SiGe in the presence of these other materials (e.g., metal conductors, dielectrics, and hard masks) is generally required for device yield and long life. The etching process for SiGe may be a plasma etching process. However, using a plasma etching process on the SiGe layer may cause damage to either or both the gate insulating layer and the semiconductor substrate. The etching process may also remove portions of the semiconductor substrate by etching the gate insulating layer exposed by the gate electrode. The electrical properties of the transistor may be adversely affected. To avoid such etching damage, additional protective device fabrication steps may be used, but at significant cost.

[0007] The present disclosure relates to compositions and processes for selectively etching SiGe relative to hardmask layers, gate materials (e.g., SiN, poly-Si, or SiOx), conductive materials (e.g., SiGe doped with boron), and low-k dielectric layers (e.g., SiN, poly-Si, SiOx, carbon-doped oxide, or SiCO) present in semiconductor devices. More specifically, the present disclosure relates to compositions and processes for selectively etching SiGe relative to boron-doped SiGe or low-k dielectric layers.

[0008] In one aspect, the disclosure features an etching composition that includes: a) at least one fluorine-containing acid, including hydrofluoric acid or hexafluorosilicic acid; b) at least one oxidizing agent; c) at least one organic acid or anhydride thereof, where the at least one organic acid includes formic acid, acetic acid, propionic acid, or butyric acid; d) at least one polymerized naphthalenesulfonic acid; e) at least one hexafluorosilicate salt; f) at least one amine, including an amine of formula (I): N-R1R2R3, where R1 is C1-C8 alkyl optionally substituted with OH or NH2, R2 is H, or C1-C8 alkyl optionally substituted with OH, and R3 is C1-C8 alkyl optionally substituted with OH; and g) water.

[0009] In another aspect, the disclosure features a method that includes contacting a semiconductor substrate including a SiGe film with an etching composition described herein to substantially remove the SiGe film.

[0010] In another aspect, the present disclosure provides a method comprising contacting a semiconductor substrate comprising a SiGe film and a film comprising SiGe doped with boron with an etching composition to substantially remove the SiGe film, the etching composition comprising: a) at least one fluorine-containing acid comprising hydrofluoric acid or hexafluorosilicic acid; b) at least one oxidizing agent; and c) at least one organic acid or anhydride thereof, the at least one organic acid comprising formic acid, acetic acid, propionic acid, or butyric acid. or an anhydride thereof; d) at least one polymerized naphthalenesulfonic acid; e) at least one inorganic acid different from the at least one fluorine-containing acid; f) at least one amine comprising an amine of formula (I): N-R1R2R3, wherein R1 is C1-C8 alkyl optionally substituted with OH or NH2, R2 is H or C1-C8 alkyl optionally substituted with OH, and R3 is C1-C8 alkyl optionally substituted with OH; and g) water.

[0011] In yet another aspect, the disclosure features an article formed by a method described herein, where the article is a semiconductor device (eg, an integrated circuit). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] As defined herein, unless otherwise specified, all percentages expressed are to be understood as percentages by weight based on the total weight of the composition. Ambient temperature is defined to be about 16 to about 27 degrees Celsius (° C.), unless otherwise specified.

[0013] In general, the present disclosure features an etching composition (e.g., an etching composition for selectively removing SiGe) that includes: a) at least one fluorine-containing acid, including hydrofluoric acid (HF) or hexafluorosilicic acid (HSiF); b) at least one oxidizing agent, including hydrogen peroxide; c) at least one organic acid or anhydride thereof, where the at least one organic acid includes formic acid, acetic acid, propionic acid, or butyric acid; d) at least one polymerized naphthalene sulfonic acid; e) at least one amine, including an amine of formula (I): N-R1R2R3, where R1 is C1-C8 alkyl optionally substituted with OH or NH2, R2 is H, or C1-C8 alkyl optionally substituted with OH, and R3 is C1-C8 alkyl optionally substituted with OH; and f) water.

[0014] In general, the etching compositions of the present disclosure may include at least one (e.g., two, three, or four) fluorine-containing acid. The fluorine-containing acid described herein may be an inorganic acid such as HF or H2SiF6. In some embodiments, the at least one fluorine-containing acid is present in an amount of at least about 0.05 wt.% (e.g., at least about 0.06 wt.%, at least about 0.07 wt.%, at least about 0.08 wt.%, at least about 0.09 wt.%, at least about 0.1 wt.%, at least about 0.15 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 about 2 wt.% or less (e.g., about 1.9 wt.% or less, about 1.8 wt.% or less, about 1.7 wt.% or less, about 1.6 wt.% or less, about 1.5 wt.% or less, about 1.2 wt.% or less, about 1 wt.% or less, about 0.5 wt.% or less, about 0.4 wt.% or less, or about 0.2 wt.% or less). Without wishing to be bound by theory, it is believed that fluorine-containing acids can facilitate and enhance the removal of SiGe on a semiconductor substrate during an etching process.

[0015] In some embodiments, the etching composition of the present disclosure can optionally include at least one (e.g., two, three, or four) salt of a fluorine-containing acid (e.g., in addition to the fluorine-containing acid described above). For example, the salt can be a fluoride salt (e.g., ammonium fluoride) or a hexafluorosilicate. Examples of hexafluorosilicate salts include ammonium hexafluorosilicate ((NH4)2SiF6) or tetraalkylammonium hexafluorosilicate (e.g., a compound containing a C1-C6 alkyl group). Examples of tetraalkylammonium hexafluorosilicates include tetramethylammonium hexafluorosilicate, tetraethylammonium hexafluorosilicate, tetrapropylammonium hexafluorosilicate (e.g., tetra(n-propyl)ammonium hexafluorosilicate or tetraisopropylammonium hexafluorosilicate), and tetrabutylammonium hexafluorosilicate (e.g., tetra(n-butyl)ammonium hexafluorosilicate, tetraisobutylammonium hexafluorosilicate, and tetra(t-butyl)ammonium hexafluorosilicate).

[0016] In some embodiments, the fluorine-containing acid salt may be present in an amount of at least about 0.01 wt.% (e.g., at least about 0.02 wt.%, at least about 0.04 wt.%, at least about 0.05 wt.%, at least about 0.06 wt.%, at least about 0.08 wt.%, at least about 0.1 wt.%, at least about 0.12 wt.%, at least about 0.14 wt.%, or at least about 0.15 wt.%) to about 1 wt.% or less (e.g., about 0.9 wt.% or less, about 0.8 wt.% or less, about 0.7 wt.% or less, about 0.6 wt.% or less, about 0.5 wt.% or less, about 0.4 wt.% or less, about 0.3 wt.% or less, about 0.2 wt.% or less, or about 0.15% or less) of the etching composition of the present disclosure. Without wishing to be bound by theory, it is believed that the fluorine-containing acid salt can reduce the etching or removal of Si on the semiconductor substrate during the etching process.

[0017] The etching composition of the present disclosure may include at least one (e.g., two, three, or four) oxidizing agent suitable for use in microelectronic applications. Examples of suitable oxidizing agents include, but are not limited to, oxidizing acids or their salts (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, perphosphoric acid and its salts, persulfuric acid and its 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 oxidizing agents can be used alone or in combination.

[0018] In some embodiments, the at least one oxidizing agent can be 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 about 20% by weight or less (e.g., about 18% by weight or less, about 16% by weight or less, about 15% by weight or less, about 14% by weight or less, about 12% by weight or less, or about 10% by weight or less) of the etching compositions of the present disclosure. Without wishing to be bound by theory, it is believed that the oxidizing agent can facilitate and enhance the removal of SiGe on the semiconductor substrate.

[0019] In general, the etching compositions of the present disclosure can include at least one (e.g., two, three, or four) organic acid or anhydride thereof. In some embodiments, the organic acid can be formic acid, acetic acid, propionic acid, or butyric acid. In some embodiments, the organic acid anhydride can be formic anhydride, acetic anhydride, propionic anhydride, or butyric anhydride. In some embodiments, the at least one organic acid or anhydride thereof (individually or in combination) can be at least about 30 wt% (e.g., at least about 35 wt%, at least about 40 wt%, at least about 45 wt%, at least about 50 wt%, at least about 55 wt%, or at least about 60 wt%) to about 90 wt% or less (e.g., about 85 wt% or less, about 80 wt% or less, about 75 wt% or less, about 70 wt% or less, about 65 wt% or less, about 60 wt% or less, about 55 wt% or less, about 50 wt% or less, about 45 wt% or less, or about 40 wt% or less) of the etching compositions of the present disclosure. Without wishing to be bound by theory, it is believed that the organic acid or anhydride thereof can facilitate and enhance the removal of SiGe on the semiconductor substrate.

[0020] The etching compositions of the present disclosure generally can 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 has the following chemical structure: [ka] and may be a sulfonic acid having the formula: wherein 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 can be at least about 0.005 wt.% (e.g., at least about 0.006 wt.%, at least about 0.007 wt.%, at least about 0.008 wt.%, at least about 0.009 wt.%, at least about 0.01 wt.%, at least about 0.02 wt.%, at least about 0.03 wt.%, at least about 0.04 wt.%, at least about 0.05 wt.%, or at least about 0.1 wt.%) to about 0.15 wt.% or less (e.g., about 0.14 wt.% or less, about 0.12 wt.% or less, about 0.1 wt.% or less, about 0.08 wt.% or less, about 0.06 wt.% or less, about 0.05 wt.% or less, about 0.04 wt.% or less, or about 0.02 wt.% or less) of the etching composition of the present disclosure. Without wishing to be bound by theory, it is believed that polymerized naphthalene sulfonic acid can selectively inhibit the removal of SiN, poly-Si, and SiCO when the etching compositions of the present disclosure are used to remove SiGe from a semiconductor substrate.

[0021] In general, the etching composition of the present disclosure can include at least one (e.g., two, three, or four) amines. In some embodiments, the amine can be an amine of formula (I): N-R1R2R3, where R1 is a C1-C8 alkyl optionally substituted with OH or NH2, R2 is H or a C1-C8 alkyl optionally substituted with OH, and R3 is a C1-C8 alkyl optionally substituted with OH. Examples of suitable amines of formula (I) include diisopropylamine, N-butyldiethanolamine, N-(3-aminopropyl)-diethanolamine, N-octylglucamine, N-ethylglucamine, N-methylglucamine, and 1-[bis(2-hydroxyethyl)amino]-2-propanol.

[0022] In some embodiments, the at least one amine can be at least about 0.001 wt. % (e.g., at least about 0.002 wt. %, at least about 0.004 wt. %, at least about 0.005 wt. %, at least about 0.006 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 about 0.15 wt. % or less (e.g., about 0.14 wt. % or less, about 0.12 wt. % or less, about 0.1 wt. % or less, about 0.08 wt. % or less, about 0.06 wt. % or less, about 0.05 wt. % or less, about 0.04 wt. % or less, or about 0.02 wt. % or less) of the etching composition of the present disclosure. Without wishing to be bound by theory, it is believed that amines can selectively inhibit the removal of SiN, poly-Si, and SiCO when SiGe is removed from a semiconductor substrate using the etching compositions of the present disclosure.

[0023] Generally, the etching compositions of the present disclosure can include water as a solvent. In some embodiments, the water can be deionized, ultra-pure, free of organic contaminants, and have a minimum resistivity of about 4 to about 17 megaohms, or at least about 17 megaohms. In some embodiments, water is present in an amount of at least about 10% by weight (e.g., at least about 12% by weight, at least about 14% by weight, at least about 15% by weight, at least about 16% by weight, at least about 18% 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, 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 about 75% by weight or less (e.g., about 70% by weight or less, about 65% by weight or less, about 60% by weight or less, about 55% by weight or less, about 50% by weight or less, about 45% by weight or less, about 40% by weight or less, about 35% by weight or less, about 30% by weight or less, about 25% by weight or less, or about 20% by weight or less). Without wishing to be bound by theory, it is believed that if the amount of water exceeds 75% by weight of the composition, it will adversely affect the SiGe etch rate and reduce its removal during the etching process. On the other hand, without wishing to be bound by theory, it is believed that the etching composition of the present disclosure should contain a certain level of water (e.g., at least about 10% by weight) to keep all other components solubilized and avoid reducing etching performance.

[0024] In some embodiments, the etching composition of the present disclosure can further include at least one (e.g., two, three, or four) organic solvent. In some embodiments, the at least one organic solvent can include an alcohol or an alkylene glycol ether. Examples of suitable organic solvents include propylene glycol, hexylene glycol, 1,3-propanediol, ethylene glycol butyl ether, and 3-methoxy-3-methyl-1-butanol. In some embodiments, the at least one organic solvent can be at least about 10% by weight (e.g., at least about 15% by weight, at least about 20% by weight, at least about 25% by weight, at least about 30% by weight, or at least about 35% by weight) to about 40% by weight or less (e.g., about 35% by weight or less, about 30% by weight or less, about 25% by weight or less, about 20% by weight or less, or about 15% by weight or less) of the etching composition.

[0025] In some embodiments, the etching composition of the present disclosure can further include at least one (e.g., two, three, or four) sugar alcohols (e.g., mannitol or sorbitol). In some embodiments, the at least one sugar alcohol can be at least about 0.001% (e.g., at least about 0.002%, at least about 0.005%, at least about 0.01%, at least about 0.02%, or at least about 0.05%) to about 0.1% or less (e.g., about 0.08% or less, about 0.06% or less, about 0.05% or less, about 0.04% or less, about 0.02% or less, or about 0.01% or less) by weight of the etching composition. Without wishing to be bound by theory, it is believed that the inclusion of a sugar alcohol in the etching composition of the present disclosure can suppress the polysilicon etch rate.

[0026] In some embodiments, the etching compositions of the present disclosure can further include at least one (e.g., two, three, or four) boronic acid. For example, the boronic acid can be of the following formula: RB(OH)2, where R is C1-C 10alkyl, aryl, or heteroaryl, where aryl or heteroaryl optionally has 1 to 6 (e.g., 1, 2, 3, 4, 5, or 6) C-C 10 Examples of suitable boronic acids include phenylboronic acid and naphthalene-1-boronic acid.

[0027] In some embodiments, the at least one boronic acid may be 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%, or at least about 0.3 wt%) to about 0.5 wt% or less (e.g., about 0.4 wt% or less, about 0.3 wt% or less, about 0.2 wt% or less, about 0.1 wt% or less, about 0.08 wt% or less, or about 0.05 wt% or less) of the etching composition. Without wishing to be bound by theory, it is believed that the inclusion of boronic acid in the etching composition of the present disclosure can inhibit the SiOx etching rate.

[0028] In some embodiments, the etching composition of the present disclosure can further include at least one (e.g., two, three, or four) inorganic acid (e.g., mineral acid). Examples of suitable inorganic acids include sulfuric acid and boric acid. In general, the inorganic acids described herein are not boronic acids, since boronic acids are considered organic acids.

[0029] In some embodiments, the at least one inorganic acid can be at least about 0.1 wt. % (e.g., 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. %, at least about 1 wt. %, at least about 2 wt. %, or at least about 3 wt. %) to about 5 wt. % or less (e.g., about 4.5 wt. % or less, about 4 wt. % or less, about 3.5 wt. % or less, about 3 wt. % or less, about 2.5 wt. % or less, about 2 wt. % or less, about 1.5 wt. % or less, or about 1 wt. % or less) of the etching composition.

[0030] In some embodiments, the etching compositions of the present disclosure can have a pH of at least about 1 (e.g., at least about 1.2, at least about 1.4, at least about 1.5, at least about 1.6, at least about 1.8, at least about 2, at least about 2.2, at least about 2.4, or at least about 2.5) and / or about 3 or less (e.g., about 2.8 or less, about 2.6 or less, about 2.5 or less, about 2.4 or less, about 2.2 or less, about 2 or less, or about 1.5 or less). Without wishing to be bound by theory, it is believed that etching compositions having a pH higher than 3 do not have sufficient SiGe selectivity to low-k dielectric materials (e.g., SiOx) because such etching compositions may have significantly increased low-k dielectric material etch rates. Furthermore, it is believed that etching compositions having a pH lower than 1 may decompose certain components in the composition due to strong acidity.

[0031] Further, in some embodiments, the etching compositions of the present disclosure may contain optional additives such as pH adjusters, corrosion inhibitors, surfactants, additional organic solvents, biocides, and antifoaming agents. Examples of suitable additives include alcohols (e.g., polyvinyl alcohol) and organic acids (e.g., iminide acetic acid, malonic acid, oxalic acid, succinic acid, and malic acid). Examples of suitable antifoaming agents include polysiloxane antifoaming agents (e.g., polydimethylsiloxane), polyethylene glycol methyl ether polymers, ethylene oxide / propylene oxide copolymers, and glycidyl ether-capped acetylene diol ethoxylates (e.g., those described in U.S. Pat. No. 6,717,019, which is incorporated herein by reference). Examples of suitable surfactants may be cationic, anionic, nonionic, or amphoteric.

[0032] In general, the etching compositions of the present disclosure can have a relatively high SiGe / dielectric material (e.g., SiN, polysilicon, or SiCO) etch selectivity (i.e., the ratio of the SiGe etch rate to the dielectric material etch rate is large when the etch rates are measured under the same conditions). In some embodiments, the etching compositions can have a SiGe / 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 about 500 or less (e.g., about 100 or less).

[0033] In some embodiments, the etching compositions of the present disclosure can have a relatively low etch rate for removing films including SiGe doped with boron (i.e., SiGe:B). For example, the etching compositions can have a SiGe:B etch rate of about 3 Å / min or less (e.g., about 2.5 Å / min or less, about 2 Å / min or less, about 1.5 Å / min or less, about 1 Å / min or less, or about 0.5 Å / min or less) to 0 Å / min at 25° C.

[0034] In some embodiments, the etching compositions of the present disclosure may specifically exclude one or more additive components, in any combination of two or more, such as organic solvents, pH adjusters, polymers, oxygen scavengers, quaternary ammonium compounds (including quaternary ammonium hydroxides (e.g., TMAH) and salts), amines, alkali bases (e.g., NaOH, KOH, LiOH), surfactants other than antifoam agents, antifoaming agents, fluorine-containing compounds (e.g., fluoride compounds or fluorinated compounds (e.g., polymer / surfactants)), abrasives (e.g., silica / ceria abrasives, non-ionic abrasives, surface-modified abrasives, or negatively / positively charged abrasives), silicon-containing compounds (e.g., silicates or silanes (e.g., alkoxysilanes)), surfactants (e.g., tetrahydrofuran ... For example, cationic surfactants, anionic surfactants, or nonionic surfactants), plasticizers, hydroxycarboxylic acids (e.g., those containing more than two hydroxyl groups), carboxylic acids and polycarboxylic acids lacking amino groups, cyclic compounds (e.g., azoles (e.g., diazoles, triazoles, or tetrazoles), triazines, and cyclic compounds containing at least two rings, such as substituted or unsubstituted naphthalenes, or substituted or unsubstituted biphenyl ethers), buffers, non-azole corrosion inhibitors, and metal salts (e.g., metal halides).

[0035] The etching composition of the present disclosure can be prepared by simply mixing the components, or by blending two compositions in a kit. The first composition in the kit can be an aqueous solution of an oxidizing agent (e.g., H2O2). The second composition in the kit can contain the remaining components of the etching composition of the present disclosure in concentrated form in a predetermined ratio, such that blending of the two compositions results in the desired etching composition of the present disclosure.

[0036] In some embodiments, the present disclosure features a method of etching a semiconductor substrate including at least one SiGe film. The method can include contacting the semiconductor substrate including at least one SiGe film with an etching composition of the present disclosure to remove the SiGe film. 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. In some embodiments, the method does not substantially remove metal conductors (e.g., Cu) or dielectric materials (e.g., SiN, polysilicon, or SiCO) in the semiconductor substrate. For example, the method does not remove more than about 5% by weight (e.g., more than about 3% by weight or more than about 1% by weight) of metal conductors or dielectric materials in the semiconductor substrate.

[0037] In some embodiments, the SiGe film in the semiconductor substrate can include at least about 10% by weight (e.g., at least about 12% by weight, at least about 14% by weight, at least about 15% by weight, at least about 16% by weight, at least about 18% by weight, or at least about 20% by weight) and / or about 35% by weight or less (e.g., about 34% by weight or less, about 32% by weight or less, about 30% by weight or less, about 28% by weight or less, about 26% by weight or less, about 25% by weight or less, about 24% by weight or less, about 22% by weight or less, about 20% by weight or less, about 18% by weight or less, about 16% by weight or less, or about 15% by weight or less) of Ge in the SiGe film. Without wishing to be bound by theory, it is believed that SiGe films containing about 10% by weight to about 35% by weight of Ge can be more easily removed from the semiconductor substrate by an etching composition compared to films containing more than 35% by weight or less than 10% by weight of Ge.

[0038] In some embodiments, the etching method comprises: (A) preparing a semiconductor substrate including a SiGe film; (B) contacting the semiconductor substrate with an etching composition described herein; (C) rinsing the semiconductor substrate with one or more suitable rinsing solvents; (D) optionally drying the semiconductor substrate (e.g., by any suitable means that removes the rinsing solvent and does not damage the integrity of the semiconductor substrate); Includes.

[0039] In some embodiments, the present disclosure also features a method of etching a semiconductor substrate including a SiGe film and a film including SiGe doped with boron. The method can include contacting the semiconductor substrate with an etching composition of the present disclosure to remove the SiGe film. In some embodiments, the method does not substantially remove the film including SiGe doped with boron.

[0040] Semiconductor substrates, including SiGe, that are etched in this manner may contain organic and metal-organic residues, as well as a range of metal oxides, some or all of which may also be removed during the etching process.

[0041] The semiconductor substrates (e.g., wafers) described herein are generally composed of silicon, silicon germanium, III-V compounds such as GaAs, or any combination thereof. The semiconductor substrates may further include exposed integrated circuit structures such as interconnect features (e.g., metal lines and dielectric materials). Metals and metal alloys used in the 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 substrates may also include layers of interlayer dielectrics, polysilicon, silicon oxide, silicon nitride, silicon carbide, titanium oxide, and carbon-doped silicon oxide.

[0042] The semiconductor substrate may be contacted with the etching composition by any suitable method, such as by placing the etching composition in a tank and dipping and / or immersing the semiconductor substrate in the etching composition, by spraying the etching composition onto the semiconductor substrate, by pouring the etching composition onto the semiconductor substrate, or any combination thereof.

[0043] Etching compositions of the present disclosure 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.). Because the etch rate of SiGe increases with temperature in this range, processes at higher temperatures can be carried out for shorter times. Conversely, lower etch temperatures typically require longer etch times.

[0044] Etching times can vary over a wide range depending on the particular etching method, thickness, and temperature used. When etching in a submerged batch 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 a single wafer process 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).

[0045] Mechanical agitation means can be used to further enhance the etching ability of the etching composition of the present disclosure. Examples of suitable agitation means include circulation of the etching composition over the substrate, streaming or spraying of the etching composition over the substrate, and ultrasonic or megasonic agitation during the etching process. The orientation of the semiconductor substrate with respect to ground can be at any angle. Horizontal or vertical orientation is preferred.

[0046] Following etching, the semiconductor substrate may be rinsed with a suitable rinsing solvent for about 5 seconds to about 5 minutes, with or without agitation. Multiple rinsing steps using different rinsing solvents may be used. Examples of suitable rinsing solvents include, but are not limited to, deionized (DI) water, methanol, ethanol, isopropyl alcohol, N-methylpyrrolidinone, γ-butyrolactone, dimethylsulfoxide, ethyl lactate, and propylene glycol monomethyl ether acetate. Alternatively or additionally, an aqueous rinse with a pH>8 (such as dilute aqueous ammonium hydroxide) may be used. Examples of rinsing solvents include, but are not limited to, dilute aqueous ammonium hydroxide, DI water, methanol, ethanol, and isopropyl alcohol. The rinsing solvent may be applied using a means similar to that used in applying 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.

[0047] Optionally, the semiconductor substrate is dried after the rinsing step. Any suitable drying means known in the art can be used. Examples of suitable drying means include spin drying, flowing a drying gas over the semiconductor substrate, or heating the semiconductor substrate with a heating means such as a hot plate or infrared lamp, Maragoni drying, Rotagoni drying, IPA drying, or any combination thereof. Drying time depends on the specific method used, but is typically on the order of 30 seconds to several minutes.

[0048] In some embodiments, the etching methods described herein further include forming a semiconductor device (eg, an integrated circuit device such as a semiconductor chip) from the semiconductor substrate obtained by the aforementioned method.

[0049] 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

[0050] Unless otherwise stated, percentages listed are by weight (wt %). Unless otherwise stated, controlled stirring during testing was performed with a 1 inch stir bar at 250 rpm.

[0051] General Procedure 1 formulation mixing The etching composition samples were prepared by adding the remaining components of the formulation to the calculated amount of solvent with stirring. After a homogeneous solution was obtained, optional additives, if used, were added.

[0052] General Procedure 2 Materials and Methods Blanket film etch rate measurements of the films were performed using commercially available unpatterned 300 mm diameter wafers that were diced into 0.5 inch by 1.0 inch test coupons for evaluation. The primary blanket film materials used for testing included: 1) a SiGe film having a thickness of about 500 Å deposited on a silicon substrate; 2) a SiN film having a thickness of about 600 Å deposited on a silicon substrate; 3) a polysilicon film having a thickness of about 1000 Å deposited on a silicon substrate; 4) a SiCO film having a thickness of about 200 Å deposited on a silicon substrate; 5) a SiOx film having a thickness of about 1200 Å deposited on a silicon substrate; and 6) a boron doped SiGe film having a thickness of about 250 Å deposited on a silicon substrate.

[0053] Blanket film test coupons were measured for thickness before and after processing to determine the etch rate of the blanket films. For SiGe, SiOx and polysilicon blanket films, film thickness was measured before and after processing by ellipsometry using a Woollam VASE.

[0054] General Step 3 Etching evaluation by beaker test All blanket film etching tests were performed in a temperature controlled water batch (25°C) in a 125mL PFA bottle containing 100g of sample solution with continuous stirring at 250 rpm, with the PFA screw in place at all times to minimize evaporation losses. All blanket test coupons with blanket dielectric film exposed on one side of the sample solution were diced by a diamond scribe into square test coupon sizes of 0.5" x 1.0" for beaker scale testing. Each individual test coupon was held in place using a single 4" long locking plastic tweezers clip. The test coupons held at one end by the locking tweezers clip were suspended in a 125mL PFA bottle and immersed in 100g of test solution with the solution continuously stirred at 250 rpm at 25°C. The test coupons were left undisturbed in the stirred solution until the treatment time (described in General Procedure 3A) had elapsed. After the treatment time in the test solution had elapsed, the sample coupons were immediately removed from the 125mL PFA bottle and rinsed according to General Procedure 3A. After the final IPA rinse step, all test coupons were subjected to a filtered nitrogen gas blow-off step using a handheld nitrogen gas blower, which forced all traces of IPA out to provide a final dry sample for test measurements.

[0055] General Procedure 3A (Blanket Test Coupon) Immediately after 2-10 min of treatment time according to General Procedure 3, the coupons were immersed in a 300 mL volume of ultra-high purity deionized (DI) water with gentle agitation for 15 s, followed by immersion in 300 mL of isopropyl alcohol (IPA) with gentle agitation for 15 s, and finally rinsed in 300 mL of IPA with gentle agitation for 15 s. The process was completed according to General Procedure 3.

[0056] Example 1 Formulation Examples 1-8 (FE-1-FE-8) were prepared according to General Procedure 1 and evaluated according to General Procedures 2, 3, and 3A. Specifically, for each tested substrate, etching tests were performed at 25° C. for 2 minutes while the etching composition was stirred at 250 rpm. The formulations and test results are summarized in Table 1 below. [Table 1]

[0057] As shown in Table 1, FE-1 to FE-3 all showed relatively high SiGe25 / SiGe:B, SiGe25 / poly-Si, SiGe25 / SiCO, SiGe25 / SiOx, and SiGe25 / SiN etch selectivities. In particular, FE-2 (containing acetic anhydride) surprisingly showed a significant decrease in the SiGe:B etch rate compared to FE-1 (not containing acetic anhydride). Furthermore, FE-3 (containing phenylboronic acid) surprisingly further decreased the SiGe:B etch rate compared to FE-2 (not containing phenylboronic acid).

[0058] Example 2 Formulation examples 4-6 (FE-4-FE-6) were prepared according to general procedure 1 and evaluated according to general procedures 2, 3 and 3A. For each test substrate, etching tests were performed at 24° C. with the etching composition stirred at 250 rpm. Etch times were 60 seconds for SiGe21, 10 minutes for SiOx, and 90 seconds for silicon. The formulations and test results are summarized in Table 2 below. [Table 2]

[0059] As shown in Table 2, FE-4 to FE-6 all showed relatively high SiGe21 / SiOx etching selectivity. On the other hand, FE-5 and FE-6 (containing ammonium hexafluorosilicate) surprisingly showed a significant reduction in Si loss compared to FE-4 (not containing ammonium hexafluorosilicate).

[0060] Although the invention has been described in detail with reference to specific embodiments thereof, it will be understood that modifications and variations are within the spirit and scope of what is described and claimed.

Claims

1. at least one fluorine-containing acid comprising hydrofluoric acid or hexafluorosilicic acid; at least one oxidizing agent; at least one organic acid or anhydride thereof, wherein the at least one organic acid comprises formic acid, acetic acid, propionic acid, or butyric acid; at least one polymerized naphthalene sulfonic acid; at least one hexafluorosilicate; Formula (I): NR １ R ２ R ３ (In the formula, R １ is OH or NH ２ C optionally substituted with １ -C ８ alkyl, and R ２ is C optionally substituted with H or OH １ -C ８ alkyl, and R ３ is C optionally substituted with OH １ -C ８ at least one amine, including an amine of the formula (I), Water and 1. An etching composition comprising:

2. The at least one polymerized naphthalene sulfonic acid is 【Chemical 1】 and a sulfonic acid having the structure n is 3 to 6; The composition of claim 1.

3. 10. The composition of claim 1, wherein the at least one polymerized naphthalene sulfonic acid is present in an amount of from 0.005% to 0.15% by weight of the composition.

4. 2. The composition of claim 1, wherein the amine of formula (I) is diisopropylamine, N-butyldiethanolamine, N-(3-aminopropyl)-diethanolamine, N-octylglucamine, N-ethylglucamine, N-methylglucamine, or 1-[bis(2-hydroxyethyl)amino]-2-propanol.

5. The composition of claim 4, wherein the at least one amine is present in an amount of from 0.001% to 0.15% by weight of the composition.

6. 10. The composition of claim 1, wherein the at least one fluorine-containing acid is present in an amount of 0.05% to 2% by weight of the composition.

7. 10. The composition of claim 1, wherein the at least one oxidizing agent comprises hydrogen peroxide or peracetic acid. thing.

8. The composition of claim 1, wherein the at least one oxidizing agent is present in an amount of from 5% to 20% by weight of the composition.

9. The composition of claim 1 , wherein the at least one organic acid or anhydride thereof comprises acetic acid or acetic anhydride.

10. 10. The composition of claim 1, wherein the at least one organic acid or anhydride thereof is present in an amount of from 30% to 90% by weight of the composition.

11. 10. The composition of claim 1, wherein the at least one hexafluorosilicate comprises ammonium hexafluorosilicate or a tetraalkylammonium hexafluorosilicate.

12. 10. The composition of claim 1, wherein the at least one hexafluorosilicate salt is present in an amount of from 0.01% to 1% by weight of the composition.

13. The composition of claim 1, wherein the water is present in an amount of from 10% to 75% by weight of the composition.

14. The composition of claim 1 further comprising at least one organic solvent.

15. The composition of claim 14 , wherein the at least one organic solvent comprises an alcohol or an alkylene glycol ether.

16. The composition of claim 15, wherein the at least one organic solvent comprises propylene glycol, hexylene glycol, 1,3-propanediol, or ethylene glycol butyl ether.

17. The composition of claim 14, wherein the at least one organic solvent is present in an amount of from 10% to 40% by weight of the composition.

18. The composition of claim 1 further comprising at least one inorganic acid.

19. 20. The composition of claim 18, wherein the at least one inorganic acid comprises sulfuric acid or boric acid.

20. 19. The composition of claim 18, wherein the at least one inorganic acid is present in an amount of 0.1% to 5% by weight of the composition.

21. 10. The composition of claim 1 having a pH of 1 to 3.

22. the at least one fluorine-containing acid comprises hydrofluoric acid and is present in an amount of 0.05% to 0.5% by weight of the composition; the at least one oxidizing agent is present in an amount of 5% to 10% by weight of the composition; the at least one organic acid or anhydride thereof is present in an amount of 50% to 80% by weight of the composition; the at least one polymerized naphthalene sulfonic acid is present in an amount of 0.005% to 0.1% by weight of the composition; the at least one hexafluorosilicate is present in an amount of 0.01% to 1% by weight of the composition; the at least one amine is present in an amount of 0.001% to 0.1% by weight of the composition; The composition of claim 1.

23. 23. The composition of claim 22, wherein the at least one oxidizing agent is 6% to 10% by weight of the composition.

24. 23. The composition of claim 22, wherein the at least one organic acid or anhydride thereof is 60% to 80% by weight of the composition.

25. 23. The composition of claim 22, wherein the at least one polymerized naphthalene sulfonic acid is 0.005% to 0.05% by weight of the composition.

26. 23. The composition of claim 22, wherein the at least one hexafluorosilicate is 0.05% to 0.5% by weight of the composition.

27. 23. The composition of claim 22, wherein the at least one amine is 0.005% to 0.05% by weight of the composition.

28. The composition of claim 22, further comprising at least one inorganic acid.

29. 30. The composition of claim 28, wherein the at least one inorganic acid comprises sulfuric acid.

30. 29. The composition of claim 28, wherein the at least one inorganic acid is present in an amount of 0.1% to 5% by weight of the composition.

31. hydrofluoric acid, Hydrogen peroxide and Acetic acid, 【Chemistry 2】 and n is 3 to 6, N-(3-aminopropyl)-diethanolamine, Sulfuric acid, ammonium hexafluorosilicate, Water and The composition of claim 1 comprising:

32. hydrofluoric acid in an amount of 0.05% to 0.5% by weight of the composition; hydrogen peroxide in an amount of 5% to 10% by weight of the composition; acetic acid in an amount of 50% to 80% by weight of the composition; 【Chemistry 3】 wherein n is 3 to 6 and is present in an amount of 0.005% to 0.1% by weight of the composition; N-(3-aminopropyl)-diethanolamine in an amount of 0.001% to 0.1% by weight of the composition; sulfuric acid in an amount of 0.1% to 5% by weight of the composition; ammonium hexafluorosilicate in an amount of 0.01% to 1% by weight of the composition; Water and 32. The composition of claim 31 , comprising:

33. contacting a semiconductor substrate containing a SiGe film with the composition of claim 1 to remove said SiGe film; A method comprising:

34. 34. The method of claim 33, wherein the SiGe film comprises 10% to 25% Ge by weight.

35. 34. The method of claim 33, further comprising rinsing the semiconductor substrate with a rinsing solvent after said contacting.

36. 36. The method of claim 35, further comprising drying the semiconductor substrate after said rinsing.

37. 34. The method of claim 33, wherein the method does not remove SiN, poly-Si, or SiCO.

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