Use of a composition for selective etching of silicon and method for selective etching of silicon

Abstract

The present invention relates to the use of a composition for the selective etching of a silicon layer in the presence of a layer comprising a silicon-germanium alloy, the composition comprising: (a) 0.0005% to 3% of a nitroaromatic compound having the formula E1, E2, or E3, a tautomer thereof, or a salt thereof as described herein, wherein if X E1 is N, one ring carbon atom in formula E1 can be replaced by a nitrogen atom; excluding 2-hydroxy-5-nitropyridine; (b) 1% to 10% by weight of an amine having the formula E2 as described herein; and (c) water.

Description

[0001] The present invention relates to a composition for selectively etching silicon at the surface of a microelectronic device substrate relative to etching a silicon-germanium-containing material at the same surface, and a method for selectively etching silicon at the surface of a microelectronic device substrate relative to etching a silicon-germanium-containing material at the same surface. Background Technology

[0002] The fabrication of certain microelectronic devices, such as integrated circuits, may involve the selective removal of silicon (Si) material from a surface containing Si combined with silicon-germanium (SiGe). According to some example fabrication steps, Si can be used as a sacrificial layer in a structure that also contains SiGe. Based on such fabrication steps, advanced device structures, such as silicon nanowires and suspended silicon (SON) structures, can be fabricated. The steps in these processes include epitaxial deposition of alternating layers of Si and SiGe, followed by patterning and finally selective lateral etching to remove the Si layers and produce a three-dimensional silicon structure.

[0003] In certain methods for fabricating field-effect transistors (FETs) for integrated circuits, Si and SiGe materials are deposited as layers, i.e., as an “epitaxy stack” of Si and SiGe, onto a substrate. These layers are then patterned using standard techniques, such as by using a mask generated using standard photolithography. Next, oriented isotropic etching can be used to laterally etch away the sacrificial Si material, leaving SiGe nanowire or nanosheet structures.

[0004] For example, the epitaxial stack can be formed by alternating Si and SiGe layers, where the Si layer is the sacrificial layer and the SiGe layer is the channel layer. The Si layer can then be removed by selective etching, which, due to the similarity of the materials constituting the sacrificial layer and the substrate, can also inadvertently create trenches in the host substrate.

[0005] To enable the realization of smaller structures within semiconductor structures, the electronics industry is seeking solutions that selectively remove amorphous or crystalline silicon relative to SiGe layers. This is necessary to achieve well-defined nanowire or nanosheet structures.

[0006] Another potential application of Si etching relative to SiGe is Backside Power Delivery Network (BS PDN). A backside-PDN configuration contains dense micro-through-silicon vias (µTSVs) and a power / ground metal stack on the back side of the chip. This approach separates the PDN from the conventional signaling network of back-end processes (BEOL) and improves power integrity and core utilization. This approach represents a complete redesign of existing architectures because both sides of the silicon have metallization layers. To achieve this, one silicon wafer is extremely thinned via CMP and chemical etching and then connected to another wafer.

[0007] Numerous alkaline etchants have been reported for wet etching of silicon. TMAH and ammonium hydroxide are the most commonly used silicon etchants due to their known high selectivity between Si and SiO2. However, when used in processes that selectively etch silicon relative to SiGe, these etchants suffer from low levels of etch power when releasing Si from the SiGe / Si stack. Furthermore, the selectivity of these etchants for removing Si relative to SiGe is typically low, i.e., < 100:1.

[0008] EP 3 447 109 A1 discloses an etching composition comprising: water; at least one of a quaternary ammonium hydroxide compound and an amine compound; a water-miscible solvent; optionally a surfactant and optionally a corrosion inhibitor; and a method for selective silicon removal using the etching composition. US 2019 / 0085240 A1 discloses selective removal of Si relative to SiGe from a microelectronic device comprising: water; at least one of a quaternary ammonium hydroxide compound and an amine compound; a water-miscible solvent; optionally a surfactant and optionally a corrosion inhibitor; and a method for selective silicon removal using the etching composition.

[0009] WO 2023 / 280637 discloses the use of a composition for selectively etching a silicon layer in the presence of a layer comprising a silicon-germanium alloy, the composition comprising:

[0010] (a) 4% to 15% by weight of an amine having formula E1

[0011]

[0012] (b) Water;

[0013] Where X E1 X E1 and X E1 Independently selected from chemical bonds and C1-C6 alkyldiyl groups; Y E Selected from N, CR E1 And P; and R E1 Selected from H and C1-C6 alkyl groups.

[0014] European Patent Application No. 23189280.3 discloses the use of a composition for selectively etching a silicon layer in the presence of a layer comprising a silicon-germanium alloy, the composition comprising 0.1% to 5% by weight of a specific pyridine compound substituted with a carboxyl, hydroxyl, amino, amide, or cyano group, and optionally a diamine.

[0015] However, existing technological solutions cannot meet all requirements because they still have at least one of the following drawbacks:

[0016] (a) The Si / SiGe selectivity is too low to remove one or more Si layers without eroding the SiGe layer;

[0017] (b) The Si etching rate is too low, which results in a long time required to completely remove one or more Si layers;

[0018] (c) Excessively high SiGe etch rates, making it difficult to remove one or more Si layers without damaging one or more SiGe layers; and / or

[0019] (d) High Si etching anisotropy indicated by the decrease in etching rate over time.

[0020] Therefore, the object of the present invention is to improve the Si etching rate while maintaining or even improving the selectivity of Si relative to SiGe and / or maintaining or even improving the isotropic nature of Si etching. Summary of the Invention

[0021] It has now been found that the use of nitro (-NO2) substituted carbocyclic or heterocyclic aromatic compounds in combination with amines enables the Si etching rate to be increased and stabilized over a longer period of time. This is partly due to the increased isotropic etching rate (at least for Si100 and Si110) and / or the increased selectivity of Si relative to SiGe.

[0022] Therefore, one embodiment of the present invention relates to the use of a composition for selectively etching a silicon layer in the presence of a layer comprising a silicon-germanium alloy, the composition comprising:

[0023] (a) 0.0005% to 3% by weight of a nitroaromatic compound having the formula E1, E2, or E3, its tautomer, or a salt thereof.

[0024]

[0025]

[0026]

[0027] in

[0028] R E1 It is a C1 to C4 alkyl group, Cl or CN;

[0029] R E2 It is -OH, -COOH, or CHO;

[0030] X E1 X E2 Independently selected from C and N;

[0031] i is a substituent R E2 The number is 1, 2, or 3;

[0032] j is a substituent R E1 The number is 0, 1, 2, or 3;

[0033] k is a substituent R E1 The number and is either 0 or 1;

[0034] And if X E1 If N is present, then one of the ring carbon atoms in formula E1 can be replaced by a nitrogen atom;

[0035] Excluding 2-hydroxy-5-nitropyridine;

[0036] (b) 1% to 10% by weight of an amine having formula A1

[0037]

[0038] in

[0039] X A1 X A2 Independently selected from C2-C3 alkyldiyl groups;

[0040] Y A Selected from NH2 and OH;

[0041] n is 0, 1, 2, or 3;

[0042] as well as

[0043] (c) Water.

[0044] Of particular surprise is that the etching composition according to the invention is suitable for allowing highly controlled, uniform and selective etching of silicon (Si), preferably amorphous silicon (aSi) or crystalline silicon, without damaging or significantly damaging the silicon-germanium (SiGe) layer.

[0045] Another embodiment of the present invention is a method for selectively removing a silicon layer relative to a silicon-germanium layer from the surface of a microelectronic device, the method comprising:

[0046] (a) Providing a microelectronic device surface, the microelectronic device surface including the silicon layer and a layer comprising a silicon-germanium alloy;

[0047] (b) Providing an etching composition comprising the compositions as defined above and described herein; and

[0048] (c) The surface is brought into contact with the composition at a time and temperature at which the silicon layer is effectively and selectively removed relative to the silicon-germanium layer. Detailed Implementation

[0049] The purpose of the etching composition is to etch a silicon (Si) layer in the presence of a silicon-germanium alloy (SiGe) or a layer composed thereof.

[0050] The compositions used in the invention according to this subject matter comprise, are substantially composed of, or consist of the following:

[0051] (a) 0.0005% to 3% of a nitroaromatic compound having formula E1, E2, or E3 as described herein, or its tautomer, and (if applicable) its salt, wherein if X E1 If the atom is N, then one of the ring carbon atoms in formula E1 or E2 can be replaced by a nitrogen atom; except if X in formula E1 E1 It is N and R E2 If i is 1, then the -NO2 substituent must not be outside the 5th position;

[0052] (b) 1% to 10% by weight of an amine having formula A1 as described herein; and

[0053] (c) Water.

[0054] definition

[0055] As used herein, a “silicon layer” or “Si layer” is a layer that is substantially composed of elemental silicon, preferably elemental silicon. It specifically includes, but is not limited to, layers composed of: amorphous silicon, polycrystalline silicon, or (mono-)crystalline silicon; p-doped silicon; or n-doped silicon. Etching compositions are particularly suitable when etching silicon, especially amorphous silicon (aSi) or crystalline silicon (cSi), in the presence of SiGe. The term “substantially composed of silicon” means that the silicon content in the layer is greater than 90% by weight, preferably greater than 95% by weight, and even more preferably greater than 98% by weight. When using undoped silicon, it is particularly preferred that the silicon layer does not contain any other elements besides silicon. When using n- or p-doped silicon, it is particularly preferred that the silicon layer does not contain any other elements besides n-type or p-type dopants, which may be present in amounts less than 10% by weight, preferably less than 2% by weight. Preferably, the germanium content of the silicon layer is less than 5% by weight, more preferably less than 2% by weight, more preferably less than 1% by weight, and even more preferably less than 0.1% by weight. Most preferably, the silicon layer does not contain germanium.

[0056] As used herein, "silicon-germanium layer" or "SiGe layer" corresponds to a layer comprising or preferably composed of a silicon-germanium (SiGe) alloy, which is known in the art and is represented by the following formula: Si x Ge y, where x is in the range of about 0.50 to 0.90, particularly 0.60 to 0.85, and y is in the range of about 0.10 to about 0.50, particularly 0.15 to 0.40, where x + y = 1.00. SiGe25 here means that y is 0.25.

[0057] As used herein, "selective etching" (or "selective etch rate") preferably means, in the presence of a layer containing a second material (in this case, SiGe) or composed thereof, the etch rate of the composition for etching the first layer is at least 150 times, preferably at least 200 times, and most preferably at least 240 times, that of the composition for etching the second layer. x SiON or SiN should not be damaged.

[0058] As used herein, "layer" means a portion of a substrate that is disposed separately on the surface of the substrate and has a composition that is distinguishable from adjacent layers.

[0059] Term "C" x "This means that the corresponding group contains x number of C atoms. The term "C" x To C y "Alkyl" means an alkyl group having x to y carbon atoms, and unless explicitly specified, includes unsubstituted straight-chain, branched, and cyclic alkyl groups. As used herein, "alkanediyl" means a digroup of a straight-chain, branched, or cyclic alkane or a combination thereof.

[0060] Unless otherwise indicated, all percentages, ppm or similar values ​​refer to weight relative to the total weight of the corresponding composition. The terms “wt%” and “by weight %” are used synonymously herein.

[0061] The term "about" in this document includes any value that is close to the specified number and the specific number itself. Unless otherwise specified, "close to" means plus or minus 10%, preferably plus or minus 5%, more preferably plus or minus 1% relative to the specified number. Most preferably, "about" means the exact number it refers to.

[0062] All cited references are incorporated into this paper by way of citation.

[0063] Si etching rate enhancer

[0064] The composition contains a Si etch rate enhancer, also referred to herein as a “nitroaromatic compound” or “enhancer”, to improve the Si etch rate and stabilize the Si etch rate over a longer period of time, partly due to the increased isotropic etch rate (at least for Si100 and Si110) and / or the increased selectivity of Si relative to SiGe.

[0065] The reinforcing agent used in this invention is a nitroaromatic compound having the formula E1, E2, or E3, or a tautomer thereof or a salt thereof.

[0066]

[0067]

[0068]

[0069] In this article, R E1 It is a straight-chain or branched C1 to C4 alkyl group, Cl, or CN. R E2 It can be a -OH (hydroxyl), -COOH (carboxyl), or -CHO (aldehyde) substituent. X E1 X E2 It can be independently selected from C and N. i is a substituent R E2 The number is 1, 2, or 3. j is the substituent R in formulas E1 and E2. E1 The number of [substituents] is 0, 1, 2, or 3, preferably 0, 1, or 2, more preferably 0 or 1, and most preferably 0. k is the substituent R in formula E3. E1 The number is 0 or 1, preferably 0. In equation E1, if X E1 If the atom is N, then a carbon atom in the ring can also be replaced by a nitrogen atom. In this case, the nitro aromatic compound contains two nitrogen atoms in the ring.

[0070] Depending on the pH used in the composition, nitroaromatic compounds can be protonated or deprotonated, or even used in the form of their salts. The counterions in their salts can be any ion that does not interfere with etching. Typically, anionic compound salts are those containing Group 1 or 2 metal ions, tetraalkylammonium ions (like tetramethylammonium or tetraethylammonium ions), etc. Typically, cationic compound salts are those containing sulfate, sulfonate, halide ions (especially chloride ions), phosphate, etc.

[0071] Of particular surprise is that the etching composition according to the invention is suitable for allowing highly controlled, uniform and selective etching of silicon (Si), preferably amorphous silicon (aSi) or (semi)crystalline silicon, without damaging or significantly damaging the silicon-germanium (SiGe) layer.

[0072] In the first preferred embodiment of formula E1, the reinforcing agent is a nitro aromatic compound, namely X. E1 It is N:

[0073]

[0074] Alternatively, if one carbon atom in the ring is replaced by a nitrogen atom.

[0075]

[0076] 2-Hydroxy-5-nitropyridine needs to be excluded from compounds having formula E1a because it does not exhibit the desired properties. Preferably, in compounds having formula E1a, if R E2 If the OH group is -OH and i is 1, then the -NO2 substituent should not be at position 5.

[0077] Preferred examples of nitroaromatic compounds having formula E1 are those having the following:

[0078] R E1 Selected from methyl, ethyl and propyl, Cl or CN, preferably selected from methyl, ethyl, Cl or CN;

[0079] R E2 It is -OH;

[0080] i is a substituent R E2 The number is 1 or 2; and

[0081] j is a substituent R E1 The number is 0, 1, 2, or 3, preferably 0, 1, or 2, even more preferably 0 or 1, and most preferably 0;

[0082] In this embodiment, hydroxypyridine derivatives and their tautomer forms can be used:

[0083]

[0084] Nitroaromatic compounds can also be used in the form of salts with counterions that do not interfere with the substrate, such as, but not limited to, sulfate, chloride, nitrate (anions), or ammonium, tetraalkylammonium, alkali metal or alkaline earth metal ions (cations).

[0085] A particularly preferred example of an N-heteroaromatic compound having formula E1a is:

[0086]

[0087] In a second preferred embodiment of formula E1, the additive is a carbocyclic aromatic compound, that is, in formula E1, X E1It is C. These carbocyclic aromatic compounds can be nitrophenol compounds, i.e., R. E1 It is -OH, or it can be a nitrobenzoic acid or nitro-phthalic acid compound, i.e., R E1 It is -COOH.

[0088] Particularly preferred examples of nitrophenol compounds are:

[0089]

[0090] Particularly preferred examples of nitrobenzoic acid compounds are:

[0091]

[0092] Particularly preferred examples of nitro-substituted phthalic acid compounds are:

[0093]

[0094] In a third preferred embodiment, a compound having the formula E2 is used, wherein

[0095] R E1 Selected from methyl, ethyl, and propyl, preferably selected from methyl and ethyl;

[0096] j is a substituent R E1 The number is 0, 1, 2, or 3, preferably 0, 1, or 2, even more preferably 0 or 1, and most preferably 0.

[0097] A particularly preferred example of an N-heterocyclic compound having the formula E2 is:

[0098]

[0099] In the fourth preferred embodiment, a compound having the formula E3 is used, wherein

[0100] R E1 Selected from methyl, ethyl, and propyl, preferably selected from methyl and ethyl;

[0101] X E1 It is either C or N, with C being the preferred choice;

[0102] k is a substituent R E1 The number is 0 or 1, preferably 0.

[0103] Particularly preferred examples of N-heterocyclic compounds having one, two, or three nitrogen atoms of formula E3 are:

[0104]

[0105]

[0106] The reinforcing agent can be present in an amount of about 0.0005% to about 3% by weight. If this amount is too low, the reinforcing effect is too poor. Further increasing the concentration is technically feasible, but not commercially meaningful. The preferred concentration is about 0.001% to about 2% by weight, more preferably about 0.01% to about 1.5% by weight, and even more preferably about 0.02% to about 1.2% by weight. The most preferred concentration range is about 0.05% to about 1% by weight.

[0107] amine

[0108] Depending on the corresponding Si etch rate enhancer used, the composition may contain 1% to 10% by weight of an amine having formula A1 (also known as an "etcher").

[0109]

[0110] It further supports selective etching of silicon layers, preferably aSi, while the etching rate of layers containing SiGe, preferably SiGe25 or composed thereof remains high.

[0111] In formula A1, the spacer group X A1 and X A2 It is independently selected from C2-C3 alkyldiyl, preferably from 1,2-ethanediyl, 1,2-propanediyl and 1,3-propanediyl.

[0112] Y A It can be NH2 or OH, with NH2 being preferred.

[0113] n can be 0, 1, 2 or 3, preferably 0, 1 or 2, and most preferably 0 or 1.

[0114] In a first preferred embodiment, the amine is an alkanolamine, preferably an ethanolamine.

[0115] In a second preferred embodiment, the amine is a diamine, triamine, or tetraamine, preferably ethylenediamine, propane-1,2-diamine, or propane-1,3-diamine.

[0116] Particularly preferred amines are ethylenediamine, ethanolamine, propane-1,2-diamine, propane-1,3-diamine and diethylenetriamine.

[0117] The amine can be present in amounts from about 1% to about 10% by weight. If this amount is too low, the enhancing effect is too poor. Further increasing the concentration is technically feasible, but not commercially meaningful. The preferred concentration is from about 1.5% to about 8% by weight, more preferably from about 2% to about 7% by weight. The optimal concentration window is from about 3% to about 6% by weight.

[0118] Alkanolamines are known to react with carbon dioxide, even from the atmosphere, resulting in the formation of carbamic acid, carbamate, or ammonium carbonate (bicarbonate) adducts. Small amounts of the CO2 reaction product have been found to be beneficial for Si etching. To produce the CO2 reaction product, the ethanolamine or etching bath can be exposed to air or treated with pure carbon dioxide. Alternatively, the etching bath can be prepared with the addition of carbonates or bicarbonates. Useful carbonates or bicarbonates are not limited to those containing ammonium, C1 to C6 tetraalkylammonium, C1 to C6 tetraalkylphosphonium, alkali metals, or alkaline earth metals. In preferred embodiments, the carbonate or bicarbonate can be added in amounts from about 0.01% to about 5% by weight, more preferably from about 0.05% to about 2% by weight, and most preferably from about 0.1% to about 1% by weight.

[0119] The compositions according to the invention may contain one or more of the amines described herein.

[0120] water

[0121] The etching composition developed in this invention is water-based and therefore contains water. Water has several functions, such as dissolving one or more components in the composition, acting as a carrier for components, acting as an aid in removing residues, acting as a viscosity modifier for the composition, and acting as a diluent. Preferably, the water used in the composition is deionized (DI) water. The scope of water described in the following paragraph includes all water from any source in the composition.

[0122] For most applications, the weight percentage of water in the composition will be within a range having a starting point and an ending point selected from the following number groups: 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 92, 94, 96, 98, 99. Examples of ranges of water that can be used in the composition include, for example, water from about 45% to about 99% by weight, or from about 50% to about 94% by weight; or from about 60% to about 99% by weight, or from about 70% to about 96% by weight, or from about 80% to about 96% by weight, or from about 85% to about 99% by weight, or from about 90% to about 99% by weight. Other preferred embodiments of the invention may include water to achieve the desired weight percentage of other components.

[0123] organic solvents

[0124] In one embodiment, the etching composition may optionally contain one or more water-miscible organic solvents.

[0125] Examples of water-miscible organic solvents that can be used include ethylene glycol, propylene glycol, 1,4-butanediol, glycerol, tripropylene glycol methyl ether, propylene glycol propyl ether, diethylene glycol n-butyl ether (BDG), dipropylene glycol methyl ether (DPM), hexoxypropylamine, poly(ethylene oxide)diamine, dimethyl sulfoxide (DMSO), tetrahydrofurfuryl alcohol, glycerol, alcohols, sulfolane, sulfoxide, diethanolamine, triethanolamine, or mixtures thereof. Preferred solvents are alcohols, glycols, or mixtures thereof. Most preferred solvents are C2 to C6 polyols, particularly C2 to C4 polyols, including glycols such as ethylene glycol or propylene glycol, and triols such as glycerol.

[0126] For most applications, the amount of water-miscible organic solvent in the composition can be in the range of starting and ending points selected from the following list of weight percentages: 0.5, 1, 5, 7, 10, 12, 15, 20, 25, 29, 30, 33, 35, 40, 44, 49.5, 50. Examples of such ranges of solvent include about 0.5% to about 50% of the composition by weight; or about 1% to about 45% by weight; or about 1% to about 40% by weight; or about 0.5% to about 30% by weight; or about 1% to about 30% by weight; or about 5% to about 30% by weight; or about 5% to about 20% by weight; or about 7% to about 20% by weight; or about 10% to about 30% by weight; or about 15% to about 25% by weight.

[0127] In certain cases, the compositions according to the invention as defined herein may further comprise, as optional additional components, one or more water-miscible organic solvents, preferably selected from the group consisting of tetrahydrofuran (THF), N-methylpyrrolidone (NMP), dimethylformamide (DMF), dimethyl sulfoxide (DMSO), ethanol, isopropanol, butyl diethylene glycol, butyl glycol, sulfolane (2,3,4,5-tetrahydrothiophene-1,1-dioxide), and mixtures thereof; more preferably selected from the group consisting of THF, NMP, DMF, DMSO, sulfolane, and mixtures thereof.

[0128] In the context of this invention, the term "water-miscible organic solvent" preferably means an organic solvent that is miscible with water at a ratio of at least 1:1 (w / w) at 20°C and ambient pressure. In particular, compositions according to the invention that do not contain one or more water-miscible organic solvents are preferred.

[0129] In a preferred embodiment, the following composition according to the invention as defined herein is preferred, wherein, based on the total weight of the composition, the total amount of one or more water-miscible organic solvents is present in an amount from about 0.1% to about 30% by weight, preferably from about 0.5% to about 25% by weight, more preferably from about 5% to about 20% by weight, and even more preferably from about 1% to about 6% by weight.

[0130] In another preferred embodiment, the following composition according to the invention as defined herein is preferred, wherein the total amount of one or more water-miscible organic solvents is present, based on the total weight of the composition, in an amount from about 20% to about 55% by weight, preferably from about 25% to about 50% by weight, and more preferably from about 30% to about 45% by weight.

[0131] In yet another preferred embodiment, the composition according to the invention, as defined herein, is an aqueous solution substantially free of organic solvents (except for amines). In this context, "substantially free" means that the content of organic solvents is less than 1% by weight, preferably less than 0.1% by weight, even more preferably less than 0.01% by weight, even more preferably less than 0.001% by weight, and most preferably below the detection limit. Most preferably, the composition does not contain any solvents other than water (and amines).

[0132] Coordinating agent

[0133] The etching composition may optionally contain one or more coordinating agents.

[0134] Preferred ligands are 1,2-cyclohexyl diazonotetraacetic acid, 1,1,1,5,5,5-hexafluoro-2,4-pentanedione, acetylacetonate, 2,2'-azaalkyldiacetic acid, ethylenediaminetetraacetic acid, and etidronic acid. (acid), methanesulfonic acid, acetylacetone, 1,1,1-trifluoro-2,4-pentanedione, 1,4-benzoquinone, 8-hydroxyquinoline, salicylaniline; tetrachloro-1,4-benzoquinone, 2-(2-hydroxyphenyl)-benzoxazole, 2-(2-hydroxyphenyl)-benzothiazole, hydroxyquinoline sulfonic acid, sulfosalicylic acid, salicylic acid, gallic acid, pyridine, 2-ethylpyridine, 2-methoxypyridine, 3-methoxypyridine, 2-methylpyridine, dimethylpyridine, piperidine, piperazine, ethylamine, methylamine, isobutylamine, tert-butylamine, tributylamine, dipropylamine, dimethylamine Diethylene glycolamine, methyldiethanolamine, pyrrole, isoxazole, bipyridine, pyrimidine, pyrazine, pyridazine, quinoline, isoquinoline, indole, 1-methylimidazolium, diisopropylamine, diisobutylamine, aniline, pentamethyldiethylenetriamine, acetylacetamide, ammonium carbamate, pyrrolidine dithiocarbamate, dimethyl malonate, methyl acetoacetate, N-methylacetylacetamide, tetramethylammonium thiobenzoate, 2,2,6,6-tetramethyl-3,5-heptadecane, tetramethylthiuram disulfide, lactic acid, ammonium lactate, formic acid, propionic acid, γ-butyrolactone, and mixtures thereof.

[0135] The ligand may be 1,2-cyclohexyl diazonotetraacetic acid (CDTA) or may include CDTA and one or more of the other ligands mentioned above.

[0136] The following compositions according to the invention as defined herein are also preferred, wherein, based on the total weight of the composition, the amount of one or more ligands present is from about 0.01% to about 4% by weight, preferably from about 0.02% to about 1% by weight, and more preferably from about 0.05% to about 0.8% by weight.

[0137] In some embodiments, the compositions of the present invention will contain no or substantially no one or all of the ligands listed above.

[0138] surfactants

[0139] The composition may further contain one or more surfactants.

[0140] Preferred surfactants are selected from the group consisting of the following:

[0141] (i) Anionic surfactants, preferably selected from the group consisting of ammonium lauryl sulfate and fluorinated surfactants, and more preferably selected from the group consisting of: perfluorinated alkyl sulfonamide salts (preferably perfluorinated, N-substituted alkyl sulfonamide ammonium salts, PNAAS), perfluorooctane sulfonates, perfluorobutane sulfonates, perfluorononanoates and perfluorooctanoates; alkyl-aryl ether phosphates and alkyl ether phosphates;

[0142] (ii) an amphoteric surfactant, preferably selected from the group consisting of: (3-[(3-cholamidopropyl)dimethylammonium]-1-propanesulfonate) (“CHAPS”), cocamidopropylhydroxysulfonate betaine (CAS RN 68139-30-0), {[3-(dodecanoylamino)propyl](dimethyl)-ammonium}acetate, phosphatidylserine, phosphatidylethanolamine, phosphatidylcholine; and

[0143] (iii) A nonionic surfactant, preferably selected from the group consisting of glucoside alkyl ethers, glyceryl alkyl ethers, cocamidoethanolamine and lauryl dimethylamine oxide.

[0144] A more preferred surfactant in the compositions according to the invention is or comprises a perfluorinated, N-substituted alkylsulfonamide ammonium salt. A preferred surfactant (E) in the compositions according to the invention does not contain metals or metal ions.

[0145] Specific surfactants used in the compositions described herein include, but are not limited to, bis(2-ethylhexyl) phosphate, perfluoroheptanoic acid, perfluorodecanoic acid, trifluoromethanesulfonic acid, phosphonoacetic acid, dodecenylsuccinic acid, dioctadecyl hydrogen phosphate, dioctadecyl dihydrogen phosphate, dodecylamine, dodecenylsuccinic acid monodiethanolamide, lauric acid, palmitic acid, oleic acid, hinoki acid, 12-hydroxystearic acid, and dodecyl phosphate; polyoxyethylene lauryl ether (Emalmin NL-100 (Sanyo), Brij 30, Brij 98, Brij 35), dodecenylsuccinic acid monodiethanolamide (DSDA, Sanyo), ethylenediaminetetra(ethoxylate-block-propoxylate)tetraol (Tetronic 90R4), polyethylene glycol (e.g., PEG400), polypropylene glycol, polyethylene glycol ethers or polypropylene glycol ethers, and block copolymers based on ethylene oxide and propylene oxide (Newpole). PE-68 (Sanyo Corporation), Pluronic L31, Pluronic 31R1, Pluronic L61, Pluronic F-127 (Dynol 607), polyoxypropylene sucrose ether (SN008S, Sanyo Corporation), tert-octylphenoxypolyethoxyethanol (Triton X100), 10-ethoxy-9,9-dimethyldecyl-1-amine (TRITON® CF-32), branched polyoxyethylene (9) nonylphenyl ether (IGEPAL CO-250), branched polyoxyethylene (40) nonylphenyl ether (IGEPAL CO-890), polyoxyethylene sorbitan hexaoleate, polyoxyethylene sorbitan tetraoleate, polyethylene glycol dehydrated sorbitan monooleate (Tween80), dehydrated sorbitan monooleate (Span 80), combinations of Tween 80 and Span 80, alcohol alkoxylates (e.g., Pluafac) RA-20), alkyl-polyglucoside, ethyl perfluorobutyrate, 1,1,3,3,5,5-hexamethyl-1,5-bis[2-(5-norbornen-2-yl)ethyl]trisiloxane, and monomeric octadecylsilane derivatives such as SIS6952.0 (Siliclad, Gelest), siloxane-modified polysilazanes such as PP1-SG10, Siliclad Glide 10 (Gelest), silicone-polyether copolymers such as Silwet L-77 (Setre Chemicals), Silwet ECO spreading agent (Momentive), and ethoxylated fluorosurfactants (ZONYL® FSO-100, ZONYL® FSN-100); cetyltrimethylammonium bromide (CTAB), heptadecanefluorooctane sulfonic acid, tetraethylammonium, stearyltrimethylammonium chloride (Econol) TMS-28 (Sanyo Corporation), 4-(4-diethylaminophenylazo)-1-(4-nitrobenzyl)pyridinium bromide, cetylpyridinium chloride monohydrate, benzalkonium chloride, benzyl dimethyl dodecyl ammonium chloride, benzyl dimethyl hexadecyl ammonium chloride, hexadecyl trimethyl ammonium bromide, dimethyl dioctadecyl ammonium chloride, dodecyl trimethyl ammonium chloride, hexadecyl trimethyl p-toluenesulfonate ammonium, didodecyl dimethyl ammonium bromide, di(hydrogenated tallow) dimethyl ammonium chloride, tetraheptyl ammonium bromide, tetra(decyl) ammonium bromide, Aliquat® 336 and oxyphenonium bromide, guanidine hydrochloride (C(NH2)3Cl) or trifluoromethanesulfonates such as tetrabutyltrifluoromethanesulfonate, dimethyl dioctadecyl ammonium chloride, dimethyl dihexadecyl ammonium bromide and di(hydrogenated tallow) dimethyl ammonium chloride (e.g., Arquat) 2HT-75, Akzo Nobel); surfactants containing bromides, such as 1-hexadecyltrimethylammonium bromide.

[0146] The following compositions according to the invention as defined herein are also preferred, wherein, based on the total weight of the composition, the amount of one or more surfactants present is from about 0.0001% to about 1% by weight, preferably from about 0.0005% to about 0.5% by weight, and more preferably from about 0.001% to about 0.01% by weight.

[0147] In some embodiments, the compositions of the present invention will contain no or substantially no one or all of the surfactants listed above.

[0148] Corrosion inhibitors

[0149] The etching composition of the present invention may optionally contain one or more etching inhibitors. Etching inhibitors, if present, can protect silicon-germanium from etching. Examples of corrosion inhibitors include aliphatic aminocarboxylic acids, such as triethylenetetraminehexaacetic acid (TTHA), 1,3-diamino-2-hydroxypropane-N,N,N',N'-tetraacetic acid (DHPTA), methyliminodiacetic acid, propylenediaminetetraacetic acid, ethylenediaminetetraacetic acid (EDTA), butanediaminetetraacetic acid, (1,2-cyclohexanediamine)tetraacetic acid (CyDTA), diethylenetriaminepentaacetic acid (DETPA), ethylenediaminetetrapropionic acid, (hydroxyethyl)ethylenediaminetriacetic acid (HEDTA), and nitrotriacetic acid (NTA); aminophosphonic acids such as N,N,N',N'-ethylenediaminetetra(methylenephosphonic acid) (EDTMP); and carboxylic acids such as decanoic acid, citric acid, tartaric acid, gluconic acid, succinic acid, glyceric acid, oxalic acid, ascorbic acid, phthalic acid, benzoic acid, mercaptobenzoic acid, maleic acid, mandelic acid, malonic acid, lactic acid, and salicylic acid. Other possible corrosion inhibitors include propyl gallate, pyrogallol, quinolines such as 8-hydroxyquinoline, piperazines such as 1-(2-aminoethyl)piperazine, cysteine, and N,N,N',N",N"-pentamethyldiethylenetriamine (Polycat 5). Other corrosion inhibitors may include hexylamine. Some preferred corrosion inhibitors may contain sulfur-containing groups. Other preferred corrosion inhibitors may contain aminocarboxylic acids such as EDTA and CyDTA, quinolines such as 8-hydroxyquinoline, decanoic acid, 11-mercaptoundecanoic acid, piperazines such as 1-(2-aminoethyl)piperazine, benzimidazoles such as 2-mercapto-5-methylbenzimidazole, and carboxylic acids such as oxalic acid, decanoic acid, and ascorbic acid. More preferred corrosion inhibitors include decanoic acid, ascorbic acid, 11-mercaptoundecanoic acid, 1-(2-aminoethyl)piperazine, and 8-hydroxyquinoline.

[0150] For most applications, the amount of corrosion inhibitors in the composition, such as aminocarboxylic acids, carboxylic acids, quinoline, or piperazine, can be within the range of starting and ending points selected from the following list of weight percentages: 0.01, 0.05, 0.07, 0.1, 0.12, 0.15, 0.17, 0.2, 0.5, 1, 1.2, 1.5, 1.7, 2, 3, 4, 6, 8, 10, 12, 15. For example, based on the total weight of the composition, the corrosion inhibitor can be present in the composition in the following amounts: about 0.05 wt% to about 3 wt%, or about 0.01 to about 3 wt%, or about 0.1 wt% to about 5 wt%, or about 0.1 wt% to about 15 wt%; or about 0.1 wt% to about 10 wt%, or about 0.5 wt% to about 5 wt%, or about 0.05 wt% to about 2 wt%, or about 0.5 wt% to about 5 wt%.

[0151] In some embodiments, the compositions of the present invention will contain no or substantially no corrosion inhibitors listed above, that is, the compositions will not contain any or all of aminocarboxylic acids and / or carboxylic acids and / or quinolines and / or piperazines listed above.

[0152] Composition

[0153] Other commonly known components, such as dyes, chemical modifiers, and microbial agents, may be included in the etchant composition in conventional amounts, such as up to about 1%, 5%, or 10% by weight of the total composition, to the extent that they do not adversely affect the performance of the composition.

[0154] Alternatively, the compositions of the present invention may be free of or substantially free of any or all dyes, chemical modifiers, or microbial agents.

[0155] The etching solution compositions of the present invention are typically prepared by mixing the components together in a container at room temperature until all solids dissolve in the water-based medium.

[0156] Typically, the pH of the composition can be in the range of 8 to 14. In preferred embodiments, the pH of the etching composition is about 8.5 to about 13, more preferably about 9 to about 12 or about 9.5 to about 12.5, and most preferably about 9.5 to about 12.

[0157] The following compositions according to the invention, as defined herein, are particularly preferred, wherein the composition consists substantially of or comprises the following:

[0158] (a) 0.0005% to 3%, preferably 0.001% to 2%, more preferably 0.01% to 1.5%, even more preferably 0.03% to 1.2%, and most preferably 0.05% to 1% by weight of a nitroaromatic compound having formula E1, E2 or E3, preferably a nitroaromatic compound having formula E1.

[0159] (b) 1% to 10%, preferably 1.5% to 8%, more preferably 2% to 7%, and most preferably 3% to 6% by weight of an amine having formula A1;

[0160] (c) 0% to 3%, preferably 0% or 0.0005% to about 0.5% by weight of the surfactant as described above;

[0161] (d) 0% to 3%, preferably 0% or 0.01% to 4% by weight of the coordination agent as described above;

[0162] (e) Remaining water.

[0163] The following compositions according to the invention, as defined herein, are particularly preferred, wherein the composition consists substantially of or comprises the following:

[0164] (a) 0.0005% to 3%, preferably 0.01% to about 2%, more preferably about 0.02% to about 1.5%, even more preferably about 0.03% to about 1.2%, and most preferably 0.05% to 1% by weight of a nitroaromatic compound having formula E1, E2 or E3, preferably a nitroaromatic compound having formula E1.

[0165] (b) 1% to 10%, preferably 1.5% to 8%, more preferably 2% to 7%, and most preferably 3% to 6% by weight of an amine having formula A1;

[0166] (e) Remaining water.

[0167] In a particularly preferred embodiment, the composition consists essentially of a nitro aromatic compound, an amine, and water.

[0168] In this context, "substantially" means that the content of any other compound, except for the compound specifically mentioned, is less than 1% by weight, preferably less than 0.1% by weight, even more preferably less than 0.01% by weight, even more preferably less than 0.001% by weight, and most preferably below the detection limit.

[0169] The following compositions according to the invention, as defined herein, are particularly preferred, wherein the composition consists of a nitroaromatic compound having formula E1, E2 or E3, preferably having formula E1, an amine having formula A1, and water, as defined herein and to be defined based on examples.

[0170] application

[0171] In another aspect, a method is provided for selectively removing a silicon layer relative to a silicon-germanium layer from the surface of a microelectronic device, the method comprising:

[0172] (a) Providing a microelectronic device surface, the microelectronic device surface including the silicon layer and a layer comprising a silicon-germanium alloy;

[0173] (b) Providing an etching composition comprising

[0174] (i) 0.005% to 3% by weight of a nitroaromatic compound having formula E1, E2 or E3 or its tautomer.

[0175]

[0176]

[0177]

[0178] in

[0179] R E1 It is a C1 to C4 alkyl group, Cl or CN;

[0180] R E2 It is -OH, -COOH, or -COH;

[0181] X E1 X E2 Independently selected from C and N;

[0182] i is a substituent R E2 The number is 1, 2, or 3;

[0183] j is a substituent R E1 The number is 0, 1, 2, or 3;

[0184] k is a substituent R E1 The number and is either 0 or 1;

[0185] And if X E1 If N is present, then one of the ring carbon atoms in formula E1 can be replaced by a nitrogen atom;

[0186] Excluding 2-hydroxy-5-nitropyridine;

[0187] (ii) 1% to 10% by weight of an amine having formula A1

[0188]

[0189] in

[0190] X A1 X A2 Independently selected from C2-C3 alkyldiyl groups;

[0191] Y A Selected from NH2 and OH;

[0192] n is 0, 1, 2, or 3;

[0193] as well as

[0194] (iii) Water; and

[0195] (c) The surface is brought into contact with the composition at a time and temperature at which the silicon layer is effectively and selectively removed relative to the silicon-germanium layer.

[0196] In another aspect, a method for manufacturing a semiconductor device is provided, the method comprising the step of selectively removing a silicon layer from the surface of the microelectronic device relative to a silicon-germanium layer.

[0197] In another aspect, a method is provided for selectively increasing the etching rate of silicon relative to silicon-germanium in a microelectronic device comprising silicon and silicon-germanium, such as a composite semiconductor device, by etching the microelectronic device (composite semiconductor device) using a composition as described herein.

[0198] This composition is particularly useful for selectively etching silicon (Si) layers in the presence of a silicon-germanium alloy (SiGe) layer. Such layers may be present when fabricating field-effect transistors (FETs) for integrated circuits. The Si and SiGe materials are deposited on a substrate as layers, i.e., as an “epitaxy stack” of Si and SiGe. The Si layer can then be removed by selective etching, which, due to the similarity of the materials constituting the sacrificial layer and the substrate, can also inadvertently create trenches in the host substrate.

[0199] Another potential application of Si etching relative to SiGe is Backside Power Delivery Network (BS PDN), as described in IEEE Transactions on Electron Devices, Vol. 67, pp. 11-17. The backside-PDN configuration contains dense micro-through-silicon vias (µTSVs) and a power / ground metal stack on the back side of the chip. This approach separates the PDN from the conventional signaling network of back-end processes (BEOL) and improves power integrity and core utilization. This approach represents a complete redesign of existing architectures, as both sides of the silicon have metallization layers. To achieve this, one silicon wafer is extremely thinned via CMP and chemical etching and connected to another wafer. This invention describes a method for partial chemical etching.

[0200] It should be understood that the common practice is to prepare a concentrated form of the composition for dilution prior to use. For example, the composition may be manufactured in a more concentrated form and subsequently diluted at the manufacturer's facility with water, at least one oxidizing agent, or other components before and / or during use. Dilution ratios can range from about 0.1 parts diluent to 1 part composition concentrate to about 100 parts diluent to 1 part composition concentrate.

[0201] In the use of the compositions described herein, the compositions are typically contacted with the device structure for a sufficient period of about 1 minute to about 200 minutes, preferably about 5 minutes to about 60 minutes, at a temperature typically in the range of about 30°C to about 80°C, preferably about 40°C to about 70°C. Such contact times and temperatures are illustrative, and any other suitable time and temperature conditions can be used to effectively achieve the required removal selectivity. One advantage of the compositions according to the invention is the low temperature dependence of their Si / SiGe etch ratio. This Si / SiGe etch ratio has been found to be particularly advantageous at temperatures above room temperature but well below the boiling point of water.

[0202] After achieving the desired etching behavior, the composition can be readily removed from the microelectronic device to which it was previously applied, for example by rinsing, washing, or one or more other removal steps that may be desirable and effective in the given end-use application of the composition of the invention. For example, the device can be rinsed with a rinsing solution comprising deionized water, organic solvents, and / or dried (e.g., rotary drying, N2, steam drying, etc.).

[0203] Cleaning the surface of a blanket-coated wafer (removing oxides) with an aqueous solution containing about 0.1% to 5% HF by weight for about 10 to about 120 seconds at room temperature may be useful.

[0204] Preferably, the Si etching rate of the composition according to the invention is 300 nm / min or higher, more preferably 400 nm / min or higher. Preferably, the SiGe, particularly SiGe25, etching rate of the composition according to the invention is 3.5 nm / min or lower, more preferably 3.0 nm / min or lower. Preferably, the etching rate of the silicon layer is at least 100 times faster than the etching rate of the silicon-germanium layer, preferably 120 times faster, even more preferably 150 times faster, even more preferably 200 times faster, and most preferably more than 240 times faster (Si / SiGe selectivity).

[0205] Following the contact step is an optional rinsing step. The rinsing step can be performed by any suitable means, such as rinsing the substrate with deionized water using immersion or spray techniques. In a preferred embodiment, the rinsing step can be performed using a mixture of deionized water and an organic solvent such as isopropanol.

[0206] Following the contact step and the optional rinsing step is an optional drying step, which is carried out by any suitable means, such as isopropanol (IPA) vapor drying, heating, or centrifugal force. Example

[0207] The following embodiments of the present invention, including its sub-combinations, are particularly preferred:

[0208] 1. The use of a composition for selectively etching a silicon layer in the presence of a layer comprising a silicon-germanium alloy, the composition comprising:

[0209] (a) 0.0005% to 3% by weight of a nitroaromatic compound having the formula E1, E2, or E3, its tautomer or salt thereof.

[0210]

[0211]

[0212] in

[0213] R E1 It is a C1 to C4 alkyl group, Cl or CN;

[0214] R E2 It is -OH, -COOH, or -CHO;

[0215] X E1 X E2 Independently selected from C and N;

[0216] i is a substituent R E2 The number is 1, 2, or 3;

[0217] j is a substituent R E1 The number is 0, 1, 2, or 3;

[0218] k is a substituent R E1 The number and is either 0 or 1;

[0219] And if X E1 If N is present, then one of the ring carbon atoms in formula E1 can be replaced by a nitrogen atom;

[0220] Excluding 2-hydroxy-5-nitropyridine, and preferably excluding the following compounds, wherein if X in formula E1 E1 It is N and R E2 If i is 1, then the -NO2 substituent is at position 5;

[0221] (b) 1% to 10% by weight of an amine having formula A1

[0222]

[0223] in

[0224] X A1 X A2 Independently selected from C2-C3 alkyldiyl groups;

[0225] Y A Selected from NH2 and OH;

[0226] n is 0, 1, 2, or 3;

[0227] as well as

[0228] (c) Water.

[0229] 2. According to the use described in Example 1, where j or k or both j and k are 0.

[0230] 3. According to the use described in Example 1 or 2, a nitroaromatic compound having the formula E1a or E1b, preferably E1a, is used.

[0231]

[0232] .

[0233] 4. The use according to any one of embodiments 1 to 3, wherein i is 1.

[0234] 5. According to the use described in Example 2, wherein the nitroaromatic compound is selected from...

[0235] (a) 4-hydroxy-3-nitropyridine and its tautomer 3-nitropyridine-4-one

[0236] (b) 3-hydroxy-2-nitropyridine, and

[0237] (c) 2,4-Dihydroxy-3-nitropyridine and its tautomers 2-hydroxy-3-nitropyridine-4-one and 4-hydroxy-3-nitropyridine-2-one.

[0238] 6. According to the use described in Example 2, wherein the nitroaromatic compound is selected from...

[0239] (a) 4-Carboxy-3-nitropyridine,

[0240] (b) 3-Carboxy-2-nitropyridine, and

[0241] (c)2,4-Dicarboxy-3-nitropyridine.

[0242] 7. A nitro aromatic compound having the formula E2 is used according to the application described in Example 1.

[0243] 8. According to the use described in Example 7, wherein the nitro aromatic compound is selected from 2-nitropyridine-N-oxide, 3-nitropyridine-N-oxide and 4-nitropyridine-N-oxide.

[0244] 9. A nitroaromatic compound having the formula E3 is used in accordance with the application described in Example 1.

[0245] 10. The use according to Example 9, wherein the nitroaromatic compound is selected from...

[0246] (a) 4-nitroimidazole, and

[0247] (b) 3-nitro-1H-1,2,4-triazole

[0248] 11. The use according to any one of the foregoing embodiments, wherein,

[0249] Y A It is NH2; and

[0250] n is 0 or 1.

[0251] 12. The use according to any one of the foregoing embodiments, wherein X A1 Selected from ethane-1,2-diyl, propane-1,3-diyl and propane-1,2-diyl.

[0252] 13. The use according to any one of the foregoing embodiments, wherein the amine is selected from ethanolamine, ethylenediamine, 1,2-propanediamine, 1,3-propanediamine and diethylenetriamine.

[0253] 14. The use according to any one of the foregoing embodiments, wherein the amine is present in the composition in an amount of 2% to 8% by weight, preferably 3% to 6% by weight.

[0254] 15. The use according to any one of the foregoing embodiments, wherein the nitroaromatic compound is present in the composition in an amount of 0.001% to 0.75% by weight, preferably 0.01% to 0.5% by weight.

[0255] 16. The use according to any one of the foregoing embodiments, wherein the composition is substantially composed of or consists of the following:

[0256] (a) 0.001% to 1% by weight of the nitroaromatic compound having the formula E1, E2 or E3;

[0257] (b) 2% to 10% by weight of an amine having formula A1;

[0258] (c) 0% to 3% by weight of surfactant;

[0259] (d) 0% to 3% by weight of a complexing agent;

[0260] (e) Remaining water.

[0261] 17. The use according to any one of the foregoing embodiments, wherein the composition is substantially composed of or consists of the following:

[0262] (a) 0.001% to 1% by weight of the nitroaromatic compound having the formula E1, E2 or E3;

[0263] (b) 2% to 10% by weight of an amine having formula A1;

[0264] (d) 0% to 3% by weight of a complexing agent;

[0265] (e) Remaining water.

[0266] 18. The use according to any one of the foregoing embodiments, wherein the composition is substantially composed of or consists of the following:

[0267] (a) 0.001% to 1% by weight of a nitroaromatic compound having formula E1, E2 or E3, preferably a nitroaromatic compound having E1;

[0268] (b) 2% to 10% by weight of an amine having formula A1;

[0269] (c) 0% to 3% by weight of surfactant;

[0270] (e) Remaining water.

[0271] 19. The use according to any one of the foregoing embodiments, wherein the composition has a pH of 9 to 13, particularly 9.5 to 12.5.

[0272] 20. A method for selectively removing a silicon layer relative to a silicon-germanium layer from the surface of a microelectronic device, the method comprising:

[0273] (a) Providing a microelectronic device surface, the microelectronic device surface including the silicon layer and a layer comprising a silicon-germanium alloy;

[0274] (b) Providing an etching composition comprising

[0275] (i) 0.0005% to 3% by weight of a nitroaromatic compound having formula E1, E2 or E3, or its tautomer or salt thereof.

[0276]

[0277]

[0278]

[0279] in

[0280] R E1 It is a C1 to C4 alkyl group, Cl or CN;

[0281] R E2 It is -OH, -COOH, or -CHO;

[0282] X E1 X E2 Independently selected from C and N;

[0283] i is a substituent R E2 The number is 1, 2, or 3;

[0284] j is a substituent R E1The number is 0, 1, 2, or 3;

[0285] k is a substituent R E1 The number and is either 0 or 1;

[0286] And if X E1 If it is N, then one of the ring carbon atoms in formula E1 or E2 can be replaced by a nitrogen atom;

[0287] Except for X in equation E1 E1 It is N and R E2 If i is 1, then the -NO2 substituent must not be outside the 5th position.

[0288] (ii) 1% to 10% by weight of an amine having formula A1

[0289]

[0290] in

[0291] X A1 X A2 Independently selected from C2-C3 alkyldiyl groups;

[0292] Y A Selected from NH2 and OH;

[0293] n is 0, 1, 2, or 3;

[0294] as well as

[0295] (iii) Water; and

[0296] (c) The surface is brought into contact with the composition at a time and temperature at which the silicon layer is effectively and selectively removed relative to the silicon-germanium layer.

[0297] 21. A method for manufacturing a semiconductor device, the method comprising the step of selectively removing a silicon layer relative to a silicon-germanium layer from the surface of a microelectronic device, as described in Example 20.

[0298] The following examples are intended to further illustrate the invention but do not limit its scope. Example

[0299] General procedures and substrates

[0300] The following substrates were used as test pieces of approximately 2.5 x 2.5 cm:

[0301] Blanket-coated wafer test piece composed of crystalline Si(100), Si(110) and Si(111).

[0302] Blanket-covered wafer test piece consisting of SiGe25 (50 nm or 100 nm) on Si.

[0303] Etching bath preparation:

[0304] The etchant is prepared by adding a corresponding enhancer and amine to DI water in specified amounts. The etchant is then transferred to a plastic beaker equipped with a thermostat.

[0305] Pre-etching:

[0306] UPW and 1 wt% hydrogen fluoride were placed in two plastic beakers. Each sample (SiGe25, Si(100), Si(110), Si(111)) was pre-etched in 1 wt% hydrogen fluoride for 60 s, then immersed in UPW for 2-3 s and dried with compressed air.

[0307] Set the etchant to 50°C ± 0.5°C. Once this temperature is reached, immerse the Si(100) or SiGe25 wafer test piece in the etchant. Etch each test piece for 0.25 to 60 minutes with stirring, depending on the substrate thickness, then rinse with DI water and dry.

[0308] The obtained thickness was determined by elliptic polarization spectroscopy. The Si etching rate was achieved using Si(100) fully immersed in the etchant (surface area 2 x 6.25 cm²). 2 ρ(Si) = 2.329 g / cm³ 2 The etching isotropic properties were determined by gravimetric analysis. To determine the etching isotropic properties, Si(100), Si(110), or Si(111) specimens were partially immersed in the etchant. The height of the etched steps was then analyzed by confocal laser scanning microscopy (CLSM) and / or stylus profilometry.

[0309] Example 1

[0310] The compositions in water depicted in Table 1 were prepared as described above. Etching rates were determined by elliptic polarization by comparing the layer thickness (SiGe25) before and after etching, or by gravimetric analysis (Si100) as described. The results are also described in Table 1.

[0311] Table 1

[0312]

[0313] wt% is given relative to the total weight of the entire composition used.

[0314] The results depicted in Table 1 show that the combination of ethylenediamine and nitro-substituted heterocycles increases the Si etching rate by up to 2 times compared to ethylenediamine. Furthermore, these additives promote improved Si / SiGe selectivity greater than 520. Pyridine derivatives with at least one hydroxyl group at the 2- or 4-position and a nitro substituent at the 3- or 5-position, as well as nitroimidazoles and nitro-substituted pyridine-N-oxides, exhibit the best results.

[0315] The comparison of Example C1.2 with Examples 1.3 and 1.4 also shows that Si etching and observable Si / SiGe selectivity require the addition of amines.

[0316] Example 2

[0317] The compositions in water depicted in Table 2 were prepared as described above. Etching rates were determined by elliptic polarization by comparing the layer thickness (SiGe25) before and after etching, or by gravimetric analysis (Si100) as described. The results are also described in Table 2.

[0318] Table 2

[0319]

[0320] The compositions in water depicted in Table 3 were prepared as described above. Etching rates were determined by elliptic polarization by comparing the layer thickness (SiGe25) before and after etching, or by gravimetric analysis (Si100) as described. The results are also described in Table 3.

[0321] Table 3

[0322]

[0323] The examples shown in Table 3 demonstrate how the etch rates of Si100 and Si110 can be improved by combining the presented nitro-substituted additives with amines.

Claims

1. The use of a composition for selectively etching a silicon layer in the presence of a layer comprising a silicon-germanium alloy, the composition comprising: (a) 0.0005% to 3% by weight of a nitroaromatic compound having the formula E1, E2, or E3, its tautomer or salt thereof. in R E1 It is a C1 to C4 alkyl group, Cl, or CN; R E2 It is -OH, -COOH, or -CHO; X E1 X E2 Independently selected from C and N; i is a substituent R E2 The number is 1, 2, or 3; j is a substituent R E1 The number is 0, 1, 2, or 3; k is a substituent R E1 The number and is either 0 or 1; And if X E1 If N is present, then one of the ring carbon atoms in formula E1 can be replaced by a nitrogen atom; Excluding 2-hydroxy-5-nitropyridine; (b) 1% to 10% by weight of an amine having formula A1 in X A1 X A2 Independently selected from C2-C3 alkyldiyl groups; Y A Selected from NH2 and OH; n is 0, 1, 2, or 3; as well as (c) Water.

2. The use according to claim 1, wherein, j or k is 0.

3. The use according to claim 1 or 2, using a nitroaromatic compound having formula E1a or E1b. 。 4. The use according to any one of claims 1 to 3, wherein, i is 1 or 2.

5. The use according to claim 1, using a nitroaromatic compound having the formula E2. According to the use described in claim 1, a nitro aromatic compound having the formula E3 is used. According to the use of any one of the preceding claims, wherein, Y A It is NH2; and n is 0 or 1. According to the use of any one of the preceding claims, wherein, X A1 It is selected from ethane-1,2-diyl, propane-1,3-diyl, and propane-1,2-diyl. According to the use of any one of the preceding claims, wherein, The amine is selected from ethanolamine, ethylenediamine, propane-1,2-diamine, propane-1,3-diamine and diethylenetriamine. According to the use of any one of the preceding claims, wherein, The amine is present in the composition in an amount of 2% to 8% by weight, preferably 3% to 6% by weight. According to the use of any one of the preceding claims, wherein, The nitroaromatic compound is present in the composition in an amount of 0.001% to 0.75% by weight, preferably 0.01% to 0.5% by weight. According to the use of any one of the preceding claims, wherein, The composition has a pH of 9 to 13, particularly 9.5 to 12.

5. A method for selectively removing a silicon layer relative to a silicon-germanium layer from the surface of a microelectronic device, the method comprising: (a) Providing a microelectronic device surface, the microelectronic device surface including the silicon layer and a layer comprising a silicon-germanium alloy; (b) Providing an etching composition comprising (i) 0.0005% to 3% by weight of a nitroaromatic compound having formula E1, E2 or E3, or its tautomer or salt thereof. in R E1 It is a C1 to C4 alkyl group, Cl, or CN; R E2 It is -OH, -COOH, or -CHO; X E1 X E2 Independently selected from C and N; i is a substituent R E2 The number is 1, 2, or 3; j is a substituent R E1 The number is 0, 1, 2, or 3; k is a substituent R E1 The number and is either 0 or 1; And if X E1 If it is N, then one of the ring carbon atoms in formula E1 or E2 can be replaced by a nitrogen atom; Excluding 2-hydroxy-5-nitropyridine; (ii) 1% to 10% by weight of an amine having formula A1 in X A1 X A2 Independently selected from C2-C3 alkyldiyl groups; Y A Selected from NH2 and OH; n is 0, 1, 2, or 3; as well as (iii) Water; and (c) The surface is brought into contact with the composition at a time and temperature at which the silicon layer is effectively and selectively removed relative to the silicon-germanium layer. A method for manufacturing a semiconductor device, the method comprising the following steps: The selective removal of the silicon layer from the surface of a microelectronic device relative to the silicon-germanium layer as described in claim 14.

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