Compositions, uses and methods for selective etching of silicon-germanium materials - Patents.com

Abstract

1. A composition for selectively etching a silicon germanium alloy (SiGe) layer in the presence of a silicon layer, comprising: (a) 1 to 10 mass % of an oxidizing agent; (b) an etching solution containing 1 to 14 mass % of a fluoride ion source; (c) 0.001 to 3 mass% of formula S1 [Formula 1] Selectivity enhancer represented by TIFF2025506779000025.tif14102, (d) 0.001 to 3 mass% of formula S31 [Case 2] an additional selectivity enhancer represented by TIFF2025506779000026.tif36125; and (e) water Including, During the ceremony, R S1 X S -OH and Y S -(CO)-OH; R S2 (i) R S1 , (ii) H, (iii) C1-C 10 Alkyl, (iv) C1-C 10 alkenyl, (v) C1-C 10 Alkynyl, and (vi)-X S1 -(O-C2H3R S6 ) m -OR S6 is selected from R S6 is selected from H and C1-C6 alkyl; R S31 , R S32 , R S33 are independently selected from C1 to C6 alkyl; R S34 , R S35 , R S36 are independently selected from H and C1-C6 alkyl; X S is linear or branched C1-C 10 Alkanediyl, linear or branched C2-C 10 Alkenyl, linear or branched C2-C10 Alkynediyl, and -X S1 -(O-C2H3R S6 ) m - selected from Y S is a chemical bond and X S is selected from X S1 is a C1-C6 alkanediyl, X S31 C1-C6 alkanediyl and -X S1 -(O-C2H3R S6 ) m - selected from The composition, wherein m is an integer from 1 to 10.

Description

[Technical field]

[0001] The present invention relates to compositions, uses and methods for selectively etching silicon-germanium materials at the surface of a microelectronic device substrate relative to silicon-containing materials at the same surface. [Background technology]

[0002] The process of fabricating certain microelectronic devices, such as integrated circuits, can include selectively removing silicon germanium (SiGe) material from a surface that includes SiGe in combination with silicon (Si). According to certain example fabrication processes, SiGe can be used as a sacrificial layer in structures that also contain silicon. Based on such fabrication processes, advanced device structures, such as silicon nanowires and silicon-on-nothing (SON) structures, can be fabricated. The steps in these methods include epitaxial deposition of structures of alternating layers of Si and SiGe, followed by removal of the SiGe layers by patterning and finally by selective lateral etching, and the three-dimensional silicon structures are generated.

[0003] In one particular embodiment of a method for fabricating field effect transistors (FETs) for integrated circuits, Si and SiGe materials are deposited as layers on a substrate, i.e., as an "epitaxial stack" of Si and SiGe. This layer is then patterned using standard techniques, for example with a mask generated by standard lithography. A directional isotropic etch can then be useful to laterally etch away the sacrificial SiGe material, leaving behind a silicon nanowire or sheet structure.

[0004] To enable smaller features in semiconductor structures, the electronics industry is searching for solutions to selectively remove SiGe layers with respect to amorphous or crystalline silicon, which is necessary to realize well-defined nanowire or nanosheet structures.

[0005] EP3447791A1 discloses an etching solution for selective removal of silicon-germanium on polysilicon from microelectronic devices, comprising water, an oxidizing agent, a water-miscible organic solvent, a fluoride ion source, and optionally a surfactant. Example 5 discloses a composition comprising H2O2, NH4F, butyl diglycol, citric acid, and Surfynol® 485, a polyethoxylated dialkylacetylene compound having an ethylene oxide content (molar) of 30, which is an agent in inhibiting the poly-Si etch rate.

[0006] Unpublished International Patent Application No. PCT / EP2021 / 072975 discloses a composition for selectively etching a layer comprising a silicon germanium alloy (SiGe) in the presence of a layer comprising silicon, the composition comprising an etching solution comprising 5-15% by weight of an oxidizing agent, 5-20% by weight of a fluoride ion source, 0.001-3% by weight of an acetylenic hydroxy compound as a selectivity enhancer, and water.

[0007] However, the state of the art solution is SiO x , SiON, or SiN have too high an etch rate to meet all requirements.

[0008] Therefore, the object of the present invention is to maintain the SiGe / Si selectivity and to form a SiGe / SiO x , SiGe / SiON or SiGe / SiN selectivity, especially SiGe / SiO x The aim is to increase selectivity. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] EP3447791A1 [Patent Document 2] International Patent Application No. PCT / EP2021 / 072975 Summary of the Invention [Problem to be solved by the invention]

[0010] By using a small amount of ammonium acrylamide compound and its derivatives, SiO x It has been found that the SiGe / Si selectivity relative to SiON or SiN is significantly and selectively improved. [Means for solving the problem]

[0011] Accordingly, one embodiment of the present invention is a composition for selectively etching a silicon germanium alloy (SiGe) layer in the presence of a silicon layer, comprising: The composition comprises: (a) 1 to 10 mass % of an oxidizing agent; (b) an etching solution containing 1 to 14 mass % of a fluoride ion source; (c) 0.001 to 3 mass% of formula S1

[0012] [ka] A selectivity enhancer represented by the formula: (d) 0.001 to 3 mass% of formula S31 [ka] an additional selectivity enhancer represented by and (e) water Including, During the ceremony, R S1 X S -OH and Y S -(CO)-OH; R S2 (i) R S1 , (ii) H, (iii) C1-C 10 Alkyl, (iv) C1-C 10 alkenyl, (v) C1-C 10 Alkynyl, and (vi)-X S1 -(O-C2H3R S6 ) m-OR S6 is selected from R S6 is selected from H and C1-C6 alkyl; R S31 , R S32 , R S33 are independently selected from C1 to C6 alkyl; R S34 , R S35 , R S36 are independently selected from H and C1-C6 alkyl; X S is linear or branched C1-C 10 Alkanediyl, linear or branched C2-C 10 Alkenyl, linear or branched C2-C 10 Alkynediyl, and -X S1 -(O-C2H3R S6 ) m - selected from Y S is a chemical bond and X S is selected from X S1 is a C1-C6 alkanediyl, X S31 C1-C6 alkanediyl and -X S1 -(O-C2H3R S6 ) m - selected from m is an integer from 1 to 10.

[0013] It is particularly surprising that the etching compositions according to the invention are suitable for enabling a very controlled and selective etching of layers comprising or consisting of a SiGe alloy, preferably SiGe layers, and also thin or ultrathin layers comprising germanium ("Ge layers"), in particular layers comprising or consisting of a SiGe alloy, while at the same time not damaging or not significantly damaging layers comprising or consisting of silicon (Si), in particular amorphous or crystalline silicon, most in particular crystalline silicon.

[0014] Another embodiment of the present invention is a method of using the compositions described herein to selectively etch a SiGe layer in the presence of a silicon layer and, optionally, a silicon oxide layer.

[0015] Yet another embodiment of the invention is a method for removing a silicon-germanium layer selectively to a silicon layer and a layer comprising or consisting of silicon oxide from a surface of a microelectronic device, the method comprising: (a) providing a microelectronic device surface comprising a silicon layer and a silicon germanium layer; (b) providing a composition as described herein; and (c) contacting the surface with the composition for a time and at a temperature effective to selectively remove the silicon-germanium layer relative to the silicon layer and any silicon oxide layer. Includes.

[0016] Yet another embodiment of the invention is a method for manufacturing a semiconductor device, the method comprising selectively removing silicon-germanium relative to Si and silicon oxide materials from a surface of a microelectronic device. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 is a diagram showing the substrate obtained after carrying out Example 1. [Diagram 2] FIG. 2 is a diagram showing the substrate obtained after carrying out Example 2. [Diagram 3] FIG. 3 is a schematic diagram of the untreated substrates from Examples 1 and 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] The etching compositions according to the present invention are particularly useful for etching silicon-germanium (SiGe) layers in the presence of silicon (Si) layers, and are particularly useful when an additional silicon oxide layer is present.

[0019] The etching composition is an etching solution containing (a) 1 to 10 mass % of an oxidizing agent, (b) 1 to 14 mass % of a fluoride ion source, and (c) 0.001 to 3 mass % of a compound of formula S1 [ka] (d) 0.001 to 3 mass % of a first selectivity enhancer represented by the formula S31 [ka] The selectivity enhancer may include an additional selectivity enhancer represented by the formula:

[0020] definition As used herein, a "silicon layer" or "Si layer" is a layer essentially made of elemental silicon, preferably made of elemental silicon. In particular, it includes, but is not limited to, a layer made of amorphous, polycrystalline or (mono)crystalline silicon, p-doped silicon or n-doped silicon. The etching composition is particularly useful when etching silicon, especially amorphous silicon (aSi), in the presence of SiGe. The term "essentially made of silicon" means that the silicon content in the layer is more than 90% by weight, preferably more than 95% by weight, even more preferably more than 98% by weight. When using undoped silicon, it is particularly preferred that the silicon layer does not contain any other elements other than silicon. When using n-doped or p-doped silicon, it is particularly preferred that the silicon layer does not contain any other elements other than n-dopants or p-dopants, which may be present in an amount of 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, preferably less than 2% by weight, more preferably less than 1% by weight, even more preferably less than 0.1% by weight. Most preferably, the silicon layer is germanium free.

[0021] As used herein, the term "silicon oxide layer" or "SiO xThe "layer" refers to a silicon oxide precursor source, such as TEOS, thermally deposited silicon oxide, or a commercially available precursor, such as SiLK (商標) , AURORA (商標) , CORAL (商標) or BLACK DIAMOND (商標) The term "silicon oxide" is intended to broadly include SiO&, CDO's siloxanes, and thermal oxides. Silicon oxide or SiO x The materials represent pure silicon oxide (SiO2) as well as impure silicon oxide containing impurities in the structure.

[0022] The term "silicon-germanium layer" or "SiGe layer" as used herein corresponds to a layer consisting essentially of silicon-germanium (SiGe) alloy known to those skilled in the art. The term "consisting essentially of silicon germanium" means that the SiGe content in the layer is more than 90% by weight, preferably more than 95% by weight, even more preferably more than 98% by weight, and most preferably consists of SiGe. When n-doped silicon germanium or p-doped silicon germanium is used, it is particularly preferred that the silicon germanium layer does not contain any other elements other than the n-dopant or p-dopant, which may be present in an amount of less than 10% by weight, preferably less than 2% by weight. Silicon germanium or SiGe is generally represented by the formula Si x Ge y In the formula, x is in the range of about 0.50 to about 0.90, particularly about 0.60 to about 0.85 or about 0.70 to about 0.90, and y is in the range of about 0.10 to about 0.50, particularly about 0.15 to about 0.40 or about 0.10 to about 0.30, and x+y=1.00. Here, SiGe25 means that y is 0.25, which is particularly preferred.

[0023] As used herein, the formula SiGe is used to represent the silicon germanium material to be removed.

[0024] The term "selectively etch" (or "selective etch rate") as used herein preferably means that when a composition according to the invention is applied to a layer comprising or consisting of a first material, in this case SiGe, in the presence of a layer comprising or consisting of a second material, in this case a silicon material, most particularly aSi, the etch rate of said composition for etching the first layer is more than 500 times, preferably more than 750 times, most preferably more than 1000 times the etch rate of said composition for the second layer. Depending on the substrate to be etched, SiO x Other layers containing or consisting of silicon, such as SiON or SiN, are also not to be missed.

[0025] As used herein, the term "layer" means a portion of a substrate that is separately deposited on a surface of the substrate and has a distinct composition relative to adjacent layers.

[0026] As used herein, "chemical bond" means that the respective moieties are not present, but adjacent moieties are cross-linked to form a direct chemical bond between the adjacent moieties. As an example, in molecule ABC, if moiety B is a chemical bond, then adjacent moieties A and C together form a group AC.

[0027] The term “C x " means that the respective group contains x number of C atoms. x ~C y "Alkyl" means an alkyl having x to y carbon atoms and, unless otherwise specified, means unsubstituted straight chain, branched and cyclic alkyl. As used herein, "alkyl" refers to a straight chain, branched or cyclic alkyl or combinations thereof. As used herein, "alkanediyl" refers to a diradical of a straight chain, branched or cyclic alkane or combinations thereof.

[0028] Any percentage, ppm or relative value refers to weight relative to the total weight of the respective composition unless otherwise specified. The term "wt%" means % by weight.

[0029] All documents cited are incorporated herein by reference.

[0030] Oxidizing agent The etching composition according to the present invention includes an oxidizer, also called an "oxidizer," which may be one or more compounds capable of oxidizing germanium in a silicon germanium alloy.

[0031] Preferably, the oxidizing agent is different from the other components of the composition, particularly the etching agent, and therefore preferably does not contain any source of fluoride ions.

[0032] Oxidizing agents contemplated herein include, but are not limited to, hydrogen peroxide, FeCl3, FeF3, Fe(NO3)3, Sr(NO3)2, CoF3, MnF3, oxone (2KHSO5KHSO4K2SO4), periodic acid, iodic acid, vanadium(V) oxide, vanadium(IV,V) oxide, ammonium vanadate, ammonium peroxymonosulfate, ammonium chlorite, ammonium chlorate, ammonium iodate, ammonium nitrate, ammonium perborate, ammonium perchlorate, ammonium periodate, ammonium persulfate, ammonium hypochlorite, ammonium hypobromite, ammonium tungstate, sodium persulfate, sodium hypochlorite, sodium perborate, sodium hypobromite, potassium iodate, potassium permanganate, potassium persulfate, Examples of suitable oxidizing species include nitric acid, potassium persulfate, potassium hypochlorite, tetramethylammonium chlorite, tetramethylammonium chlorate, tetramethylammonium iodate, tetramethylammonium perborate, tetramethylammonium perchlorate, tetramethylammonium periodate, tetramethylammonium persulfate, tetrabutylammonium peroxymonosulfate, peroxymonosulfate, ferric nitrate, urea peroxide, peracetic acid, methyl-1,4-benzoquinone (MBQ), 1,4-benzoquinone (BQ), 1,2-benzoquinone, 2,6-dichloro-1,4-benzoquinone (DCBQ), toluquinone, 2,6-dimethyl-1,4-benzoquinone (DMBQ), chloranil, alloxan, N-methyl-morpholine N-oxide, trimethylamine N-oxide, and combinations thereof. The oxidizing species may be introduced into the composition at the manufacturer prior to introduction of the composition into the device wafer, or alternatively at the device wafer, i.e., in situ.

[0033] Preferably, the oxidizing agent comprises or consists of a peroxide. Useful peroxides can be, but are not limited to, hydrogen peroxide or organic acid peroxides such as peroxymonosulfuric acid, and peroxyacetic acid, and salts thereof.

[0034] The most preferred oxidizing agent is hydrogen peroxide.

[0035] The oxidizing agent may be used in an amount of about 1 to about 10% by weight, preferably about 2 to about 8% by weight, even more preferably about 3 to about 7% by weight, and most preferably about 4 to about 6% by weight, based on the total weight of the composition.

[0036] Etching solution The etching composition according to the present invention comprises a fluoride ion source, which can be any compound capable of releasing fluoride ions.

[0037] Preferably, the etching solution is different from the other components in the composition, in particular different from the oxidizing agent, and therefore preferably does not have the ability to oxidize any material, in particular Si or SiGe, on the surface of the substrate to be treated.

[0038] Preferred etchants are selected from the group consisting of, but not limited to, ammonium fluoride, ammonium bifluoride, triethanolammonium fluoride, diglycolammonium fluoride, methyldiethanolammonium fluoride, tetramethylammonium fluoride, triethylamine trihydrofluoride, hydrogen fluoride, fluoroboric acid, tetrafluoroboric acid, ammonium tetrafluoroborate, fluoroacetic acid, ammonium fluoroacetate, trifluoroacetic acid, fluorosilicic acid, ammonium fluorosilicate, tetrabutylammonium tetrafluoroborate, and mixtures thereof. Preferably, the etchant consists of one or more of the above compounds, most preferably one of the above compounds.

[0039] Most preferably, the etching solution comprises or consists of ammonium fluoride, ammonium hydrogen fluoride, and hydrogen fluoride.Most preferably, the etching solution comprises or consists of ammonium fluoride.

[0040] The etching composition according to the present invention, which contains ammonium fluoride as an etchant, has demonstrated a stable, reproducible and controlled selective etching rate for etching a layer containing or consisting of SiGe, in particular SiGe25, in the presence of a layer containing or consisting of Si.

[0041] The etching solution may be used in an amount of about 1 to about 14 mass%, preferably about 2 to about 12 mass%, more preferably about 4 to about 10 mass%, even more preferably about 4 to about 10 mass%, and most preferably about 6 to about 8 mass%, based on the total mass of the composition.

[0042] The compositions according to the invention comprising the preferred total mass of etching solution defined herein have shown excellent etch rates in the presence of layers comprising or consisting of Si, in particular for etching layers comprising or consisting of SiGe, preferably SiGe25, and excellent etch rate selectivity.

[0043] SiGe selectivity enhancer Formula S1: [ka] The first SiGe selectivity enhancer (also referred to as the "selectivity enhancer") represented by: selectively reduces the etch rate of the Si layer, while the etch rate of the SiGe layer, preferably SiGe25, remains high, which results in a SiGe / Si, particularly SiGe2 / a-Si, selectivity of more than 500 or even more than 1000.

[0044] In formula S1, R S1 X S -OH and Y S -(CO)-OH, wherein X S is a linear or branched C1-C 10 Alkanediyl, linear or branched C2-C 10 Alkenyl, linear or branched C2-C 10 Alkynediyl or polyoxyalkylene group -X S1 -(O-C2H3R 6 ) m- and Y S1 X S or may be a chemical bond. S1 When X is a polyoxyalkylene group, S1 may be a C1-C6 alkanediyl, preferably ethanediyl, propanediyl or butanediyl, and further, it is important that m is an integer selected from 1 to 10, preferably 1 to 5, even more preferably 1 to 3, and most preferably 1 to 2. The larger m is, the less effective the selectivity enhancer is. If m is too high, the selectivity enhancer may be a-Si, SiO x , does not sufficiently reduce the etch rate of SiON or SiN.

[0045] R S2 is R S1 Preferably, R S2 is the above R S1 is the same as: Or, R S2 (ii) H, (iii) C1-C 10 Alkyl, (iv) C1-C 10 alkenyl, (v) C1-C 10 Alkynyl, and (vi)-X S1 -(O-C2H3R S6 ) m -OR S6 wherein X S1 is a C1-C6 alkanediyl, preferably ethanediyl, propanediyl or butanediyl, R S6 is selected from H and C1-C6 alkyl, preferably H, methyl or ethyl, and m is an integer from 1 to 10.

[0046] Most preferably, R S1 and R S2 is the same.

[0047] In a first preferred embodiment, R S1 X S Preferably, X S may be C1 to C8 alkanediyl, more preferably C1 to C6 alkane-1,1-diyl.

[0048] Preferably, X S is C3~C 10 It is more preferably selected from C4 to C8 alkanediyl.

[0049] Particularly preferably, X S is selected from methanediyl, ethane-1,1-diyl, and ethane-1,2-diyl. S is selected from propane-1,1-diyl, butane-1,1-diyl, pentane-1,1-diyl, and hexane-1,1-diyl. S is selected from propane-2,2-diyl, butane-2,2-diyl, pentane-2,2-diyl, and hexane-2,2-diyl. S is selected from propane-1,2-diyl, butane-1,2-diyl, pentane-1,2-diyl, and hexane-1,2-diyl. S is selected from propane-1,3-diyl, butane-1,3-diyl, pentane-1,3-diyl and hexane-1,3-diyl. Particularly preferred groups X S are butane-1,1-diyl, pentane-1,1-diyl, and hexane-1,1-diyl, heptane-1,1-diyl, and octane-1,1-diyl.

[0050] Preferably, the first selectivity enhancer is of formula S2 [ka] A compound represented by the formula: During the ceremony, R S11 , R S21 is C1~C 10 independently selected from alkyl, preferably ethyl, propyl, butyl, pentyl, hexyl, most preferably propyl, butyl, or pentyl; R S12 , RS22 are independently selected from H and C1-C4 alkyl, preferably H, methyl or ethyl.

[0051] Most preferably, the (first) selectivity enhancer has the formula S4 [ka] and is available from Evonik under the trade name Surfynol® 104.

[0052] The selectivity enhancer of the first preferred embodiment may be present in an amount of about 0.0005 to about 0.03 wt%, preferably about 0.001 to about 0.02 wt%, and most preferably about 0.005 to about 0.015 wt%. A single selectivity enhancer may increase the SiGe / Si selectivity to greater than 500, preferably greater than 750, and most preferably greater than 1000.

[0053] In a second preferred embodiment, R S1 is Y S -(CO)-OH(wherein, Y S1 is a chemical bond or the above X S (which may be the same as

[0054] Preferably, the (first) selectivity enhancer has the formula S3: [ka] The compound may be represented by the formula:

[0055] The selectivity enhancer of the second preferred embodiment may be present in an amount of from about 0.1 to about 3 wt %, preferably from about 0.5 to about 2 wt %.

[0056] Compositions according to the invention may include one or more selectivity enhancers as described herein.

[0057] Particularly preferred compositions comprise one single selectivity enhancer of the first preferred embodiment, in particular one single selectivity enhancer of formula S2 or S4.

[0058] Another particularly preferred composition comprises a first selectivity enhancer of the first preferred embodiment, in particular a first selectivity enhancer of formula S2 or S4, and further comprises a second selectivity enhancer of the second preferred embodiment, in particular a second selectivity enhancer of formula 3. When a first selectivity enhancer of formula S2 or S4 and a second selectivity enhancer of formula S3 are used, the mass ratio of the first and second selectivity enhancers is 0.0001-0.1, most preferably 0.001-0.02. The combination of the first and second selectivity enhancers improves the SiGe / Si selectivity by more than 10. 4 It can increase up to ultra.

[0059] Additional SiGe selectivity enhancers formula S31 [ka] The additional SiGe selectivity enhancer (also referred to as the "additional selectivity enhancer") further enhances the selectivity of SiGe relative to silicon layers, particularly silicon oxide layers.

[0060] In formula S31, the ammonium substituent R S31 , R S32 , R S33 may be independently selected from C1-C6 alkyl, preferably methyl, ethyl, propyl and butyl, most preferably methyl or ethyl. The acrylic substituent R S34 and R S35 and the amide substituent R S36 may be independently selected from H and C1-C6 alkyl, preferably H and C1-C4 alkyl, most preferably H. S31 is a C1-C6 alkanediyl and (poly)alkoxy group -X S1 -(O-C2H3R S6 ) m -, wherein X S1 is C1-C6 alkanediyl, preferably methyl, ethyl, propyl or butyl, and most preferably R S6is selected from H and C1-C6 alkyl, preferably H and C1-C4 alkyl, most preferably H and methyl, and m is an integer from 1 to 10, preferably 1 to 6.

[0061] In a preferred embodiment of the additional selectivity enhancer, R S31 , R S32 , R S33 is independently selected from methyl, ethyl, propyl, and butyl; R S34 , R S35 , R S36 is independently H or selected from methyl, ethyl, propyl, and butyl; X S31 is methanediyl, ethanediyl, propanediyl, butanediyl, and -X S1 -(O-C2H3R S6 ) m - selected from R S6 is selected from H, or methyl and ethyl; X S1 is methanediyl, ethanediyl, propanediyl, butanediyl, m is an integer from 1 to 6.

[0062] In another preferred embodiment of the additional selectivity enhancer, R S31 , R S32 , R S33 is independently selected from methyl and ethyl; R S34 , R S35 , R S36 are independently H or methyl; X S31 is methanediyl, ethane-1,2-diyl, propane-1,3-diyl, or butane-1,4-diyl, X S1 is methanediyl, ethane-1,2-diyl, propane-1,3-diyl, or butane-1,4-diyl, m is an integer from 1 to 6.

[0063] In another preferred embodiment, the additional selectivity enhancer is of formula S32 [ka] A compound represented by the formula: During the ceremony, R S31 , R S32 , R S33 is independently selected from methyl, ethyl, propyl, or butyl; X S31 is selected from methanediyl, ethanediyl, propanediyl, and butanediyl.

[0064] The additional selectivity enhancer is typically present in the etching composition in an amount of from about 0.005 to about 5 wt. %, preferably from about 0.01 to about 3 wt. %, even more preferably from about 0.1 to about 1 wt. %, and most preferably from about 0.1 to about 0.5 wt. %, based on the total weight of the composition.

[0065] Bath Stabilizer The composition may further include a hydroxycarboxylic acid (also referred to herein as a "bath stabilizer"), which significantly increases the lifetime of the SiGe etching composition.

[0066] As used herein, "hydroxycarboxylic acid" refers to a carboxylic acid that contains at least one carboxy group (C=O) and at least one hydroxy group (-OH).

[0067] In a preferred embodiment the hydroxycarboxylic acid is a dihydroxycarboxylic acid, in particular a dihydroxydicarboxylic acid.

[0068] A particularly preferred hydroxycarboxylic acid is tartaric acid.

[0069] The bath stabilizer may be present in the etching composition in an amount of from about 0.01 to about 3 weight percent, preferably from about 0.05 to about 2 weight percent, and most preferably from about 0.1 to about 1 weight percent, based on the total weight of the composition.

[0070] acid The etching composition according to the present invention may further comprise an acid. The acid may be an inorganic acid, an organic acid, or a combination thereof. Preferably, the acid is an organic acid, or a combination of an inorganic acid and an organic acid.

[0071] Exemplary inorganic acids may be selected from, but are not limited to, sulfuric acid or phosphoric acid. Preferably, the inorganic acid comprises or consists of a strong inorganic acid, especially sulfuric acid.

[0072] Exemplary organic acids include, but are not limited to, C1-C 10 It may be selected from mono-, di- or tri-carboxylic acids, sulfonic acids, phosphoric acids, etc. 10 Mono-, di- or tri-carboxylic acids are preferred.

[0073] In a preferred embodiment, the acid comprises or consists of a hydroxycarboxylic acid, including but not limited to citric acid and tartaric acid, In another preferred embodiment, the acetylenic compound, such as but not limited to acetylenedicarboxylic acid, also has acidic properties and therefore no additional acid is required.

[0074] When an acid is present, the acid may be used in the etching composition in an amount of about 0.1% to about 5% by weight, more preferably about 0.2% to about 4% by weight, even more preferably about 0.3% to about 3% by weight, and most preferably about 0.5% to about 2% by weight.

[0075] Organic solvents Although not preferred, the etching composition may optionally include one or more organic solvents.

[0076] In each case, the compositions according to the invention as defined herein may further comprise an optional additional component: one or more water-miscible organic solvents, preferably selected from the group consisting of tetrahydrofuran (THF), N-methylpyrrolidone (NMP), di-methylformamide (DMF), dimethylsulfoxide (DMSO), ethanol, isopropanol, butyl diglycol, 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.

[0077] The term "water-miscible organic solvent" preferably means, in the sense of the present invention, that an organic solvent fulfilling this requirement is miscible with water in a ratio of at least 1:1 (w / w) at 20° C. and at ambient pressure. Preferably, at least one water-miscible organic solvent (H) is sulfolane. In particular, compositions according to the invention which do not contain one or more water-miscible organic solvents are preferred.

[0078] In each individual case, the compositions according to the invention as defined herein (or the compositions according to the invention as described above or below as being preferred) are preferably those in which one or more water-miscible organic solvents (i.e., solvent components) are present in a total amount of from about 0.1 to about 30% by weight, preferably from about 0.5 to about 10% by weight, more preferably from about 1 to about 7.5% by weight, even more preferably from about 1 to about 6% by weight, based on the total weight of the composition.

[0079] Most preferably, the etching composition is an aqueous solution essentially free of organic solvents, where essentially free means that the organic solvent content is less than 1% by weight, preferably less than 0.1% by weight, even more preferably less than 0.01% by weight, and most preferably below the detection limit.

[0080] Surfactants The composition may further comprise one or more surfactants.

[0081] Preferred surfactants are selected from the group consisting of:

[0082] (i) anionic surfactants, preferably ammonium lauryl sulfate, fluorosurfactants, preferably selected from the group consisting of perfluorinated alkylsulfonamide salts (preferably perfluorinated, N-substituted alkylsulfonamide ammonium salts, PNAAS), perfluorooctane sulfonate, perfluorobutane sulfonate, perfluorononanoate and perfluorooctanoate; selected from the group consisting of alkyl-aryl ether phosphates and alkyl ether phosphates; (ii) zwitterionic surfactants, preferably selected from the group consisting of (3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate) ("CHAPS"), cocamidopropyl hydroxysultaine (CAS RN68139-30-0), {[3-(dodecanoylamino)propyl](dimethyl)-ammonio}acetate, phosphatidylserine, phosphatidylethanolamine, phosphatidylcholine; and (iii) Non-ionic surfactants, preferably those selected from the group consisting of glucoside alkyl ethers, glycerol alkyl ethers, cocamide ethanolamine and lauryl dimethylamine oxide. More preferred surfactants in the compositions according to the invention are perfluorinated N-substituted alkylsulfonamide ammonium salts.Preferred surfactants (E) in the compositions according to the invention do not contain metals or metal ions.

[0083] Particularly preferred surfactants are those of formula F1 [ka] (In the formula, X F2 is C1-C4 alkanediyl, R F4 is C 12 ~C 30 Alkyl or C12 ~C 30 alkenyl, and R F5 is C1-C4 alkyl It is expressed as follows.

[0084] In compositions according to the invention as defined herein, the amount of one or more surfactants present is preferably from about 0.0001 to about 1% by weight, preferably from about 0.0005 to about 0.5% by weight, more preferably from about 0.001 to about 0.01% by weight, based on the total weight of the composition.

[0085] Chelating Agents The etching composition may optionally include one or more chelating agents.

[0086] Preferred chelating agents are 1,2-cyclohexylene dinitrilotetraacetic acid, 1,1,1,5,5,5-hexafluoro-2,4-pentane-dione, acetylacetonate, 2,2'-azanediyldiacetic acid, ethylenediaminetetraacetic acid, etidronic acid, methanesulfonic acid, acetylacetone, 1,1,1-trifluoro-2,4-pentanedione, 1,4-benzoquinone, 8-hydroxyquinoline, salicylidene. Aniline;Tetrachloro-1,4-benzoquinone;2-(2-hydroxyphenyl)-benzoxazole;2-(2-hydroxyphenyl)-benzothiazole;Hydroxyquinolinesulfonic acid;Sulfosalicylic acid;Salicylic acid;Pyridine;2-ethylpyridine;2-methoxypyridine;3-methoxypyridine;2-picoline;Dimethylpyridine;Piperidine;Piperazine;Triethylamine;Triethanolamine;Ethylamine;Methylamine;Isobutylamine;Tert-butylamine;Tributylamine;Dipropylamine;Dimethylamine;Diglycolamine;Monoethanolamine;Methyldiethanolamine;Pyrrole;Isooxaamine azole, bipyridine, pyrimidine, pyrazine, pyridazine, quinoline, isoquinoline, indole, 1-methylimidazole, diisopropylamine, diisobutylamine, aniline, pentamethyldiethylenetriamine, acetoacetamide, ammonium carbamate, ammonium pyrrolidine dithiocarbamate, dimethyl malonate, methyl acetoacetate, N-methyl acetoacetamide, tetramethylammonium thiobenzoate, 2,2,6,6-tetramethyl-3,5-heptanedione, tetramethylthiuram disulfide, lactic acid, ammonium lactate, formic acid, propionic acid, gamma-butyrolactone, and mixtures thereof.

[0087] In a preferred embodiment, the chelating agent may be diethylenetriaminepentaacetic acid (DTPA), or may include DTPA and one or more other chelating agents described above. Compositions including DTPA as a chelating agent have demonstrated particularly low etch rates for silicon oxide.

[0088] Additionally, in the compositions according to the present invention as defined herein, the amount of one or more chelating agents present is preferably from about 0.01 to about 4% by weight, preferably from about 0.02 to about 1% by weight, more preferably from about 0.05 to about 0.8% by weight, based on the total weight of the composition.

[0089] composition In a preferred embodiment, the pH of the etching composition is 4 to 8, in particular 5 to 7. If the pH is too low, the etching rate of silicon oxide is too high, and if the pH is too high, the etching rate of Si is too high. The pH of the bath may be adjusted by a pH adjuster, in particular ammonia.

[0090] It is particularly preferred that the composition according to the invention as defined herein consists of hydrogen peroxide, ammonium fluoride, a first selectivity enhancer of formula S2 and S4, optionally a second selectivity enhancer of formula S3, an additional selectivity enhancer of formula S31, optionally an acid, optionally a pH adjuster, and water, as described herein and defined on the basis of the examples.

[0091] It is particularly preferred that the composition according to the invention as defined herein consists of hydrogen peroxide, ammonium fluoride, a first selectivity enhancer of formula S3, optionally a surfactant of formula S4, an additional selectivity enhancer of formula S31, optionally an acid, optionally a pH adjuster, and water, as described herein and defined on the basis of the examples.

[0092] It is particularly preferred that the composition comprises or consists of: (a) one or more oxidizing agents selected from peroxides, and preferably consisting of or including hydrogen peroxide, in an amount of about 1 to about 10% by weight, preferably about 2 to about 8% by weight, even more preferably about 3 to about 7% by weight, and most preferably about 4 to about 6% by weight; (b) one or more etching solutions comprising a fluoride ion source selected from the group consisting of ammonium fluoride, ammonium bifluoride, triethanolammonium fluoride, diglycolammonium fluoride, methyldiethanolammonium fluoride, tetramethylammonium fluoride, triethylamine trihydrofluoride, hydrogen fluoride, fluoroboric acid, tetrafluoroboric acid, ammonium tetrafluoroborate, fluoroacetic acid, ammonium fluoroacetate, trifluoroacetic acid, fluorosilicic acid, ammonium fluorosilicate, tetrabutylammonium tetrafluoroborate, and mixtures thereof, and preferably consisting of or comprising ammonium fluoride, hydrogen fluoride, or combinations thereof, in an amount of from about 1 to about 14%, preferably from about 2 to about 12%, more preferably from about 4 to about 10%, even more preferably from about 4 to about 10%, and most preferably from about 6 to about 8% by weight of the one or more etching solutions; (c) a first selectivity enhancer of formula S1, particularly of formula S2, S3 or S4, in an amount of about 0.0005 to about 0.02 wt. %, preferably about 0.005 to about 0.015 wt. %, (d) optionally a second selectivity enhancer having formula S3, if the first selectivity enhancer is not a compound of formula S3, in an amount of from about 0.1 to about 3 wt. %, preferably from about 0.5 to about 2 wt. %, of the second selectivity enhancer; (e) an additional selectivity enhancer of formula S31 in an amount of 0.01 to 5 wt. %, preferably 0.1 to 1 wt. %, (f) one or more acids, including inorganic and organic acids, preferably organic acids, more preferably C1-C 10 one or more acids selected from mono-, di- or tricarboxylic acids, even more preferably hydroxycarboxylic acids, even more preferably dihydroxydicarboxylic acids, most preferably tartaric acid, or a combination thereof, and preferably consisting of or comprising tartaric acid, in an amount of about 0.1% to about 5%, more preferably about 0.2% to about 4%, even more preferably 0.3% to 3%, most preferably 0.5 to 2% by weight; (g) optionally, one or more surfactants, including (i) anionic surfactants, preferably selected from the group consisting of ammonium lauryl sulfate, fluorosurfactants, preferably selected from the group consisting of perfluorinated alkylsulfonamide salts (preferably perfluorinated, N-substituted alkylsulfonamide ammonium salts), perfluorooctane sulfonate, perfluorobutane sulfonate, perfluorononanoate and perfluorooctanoate; alkyl-aryl ether phosphates and alkyl ether phosphates; (ii) zwitterionic surfactants, preferably selected from the group consisting of (3-[(3-cholamidopropyl)dimethylamino]phenyl]propane; (iii) one or more surfactants selected from the group consisting of a non-ionic surfactant, preferably a glucoside alkyl ether, a glycerol alkyl ether, a cocamidoethanolamine, and a lauryl dimethylamine oxide, and preferably a compound represented by formula F1, in an amount of about 0.0005 to about 0.5% by mass, more preferably about 0.001 to about 0.01% by mass, (h) optionally one or more chelating agents, such as diethylenetriaminepentaacetic acid, 1,2-cyclohexylenedinitrilotetraacetic acid, 1,1,1,5,5,5-hexafluoro-2,4-pentanedione, acetylacetonate, 2,2'-azanediyldiacetic acid, ethylenediaminetetraacetic acid, etidronic acid, methanesulfonic acid, acetylacetone, 1,1,1-trifluoro-2,4-pentanedione, 1,4-benzoquinone, 8-hydroxyquinoline, salicylidene Aniline; tetrachloro-1,4-benzoquinone, 2-(2-hydroxyphenyl)-benzoxazole, 2-(2-hydroxyphenyl)-benzothiazole, hydroxyquinolinesulfonic acid, sulfosalicylic acid, salicylic acid, pyridine, 2-ethylpyridine, 2-methoxypyridine, 3-methoxypyridine, 2-picoline, dimethylpyridine, piperidine, piperazine, triethylamine, triethanolamine, ethylamine, methylamine, isobutylamine, tert-butylamine, tributylamine, dipropylamine, dimethylamine, diglycolamine, monoethanolamine, methyldiethanolamine, pyrrole, isoxazole, bipyridine, pyrimidine, pyrazine, pyridazine, quinoline, isoquinoline, indole, 1-methylimidazole, diisopropylamine one or more chelating agents selected from the group consisting of diisobutylamine, aniline, pentamethyldiethylenetriamine, acetoacetamide, ammonium carbamate, ammonium pyrrolidine dithiocarbamate, dimethyl malonate, methyl acetoacetate, N-methyl acetoacetamide, tetramethylammonium thiobenzoate, 2,2,6,6-tetramethyl-3,5-heptanedione, tetramethylthiuram disulfide, lactic acid, ammonium lactate, formic acid, propionic acid, gamma-butyrolactone, and mixtures thereof, and preferably being or comprising 1,2-cyclohexylene dinitrilotetraacetic acid, in an amount of about 0.005 to 24% by weight, preferably in a total amount of about 0.01 to about 1% by weight, more preferably in a total amount of about 0.02 to about 0.2% by weight, based on the total weight of the composition; (k) water, the balance in each case relative to the total weight of the composition; and (l) optionally one or more water-miscible solvents, preferably selected from the group consisting of tetrahydrofuran (THF), N-methylpyrrolidone (NMP), di-methylformamide (DMF), dimethylsulfoxide (DMSO) and sulfolane (2,3,4,5-tetrahydrothiophene-1,1-dioxide) and mixtures thereof, in an amount of from about 0.1 to about 30%, preferably from about 0.5 to about 10%, more preferably from about 1 to about 7.5%, and even more preferably from about 1 to about 6% by weight; All are relative to the total weight of the composition, the pH of the composition is from about 4 to about 8, preferably from about 5 to about 7, and the % amounts of the components in each case add up to 100% by weight.

[0093] Applicable The compositions are particularly useful for selectively etching silicon germanium alloy (SiGe) layers in the presence of Si layers, especially crystalline Si, and preferably in the presence of silicon oxide.

[0094] It will be appreciated that it is common practice to create concentrated forms of the composition that are diluted prior to use. For example, the composition may be manufactured in a more concentrated form and then diluted with water, at least one oxidizing agent, or other ingredients at the manufacturer prior to and / or during use. The dilution ratio may range from about 0.1 parts diluent to 1 part composition concentrate to about 100 parts diluent.

[0095] Thus, one embodiment relates to a kit comprising, in one or more containers, one or more components adapted to form a composition as described herein. Preferably, one container contains at least one oxidizing agent and a second container contains the remaining components, such as at least one etchant, at least one selectivity enhancing agent, water, and optionally other components as described herein, for mixing at the time of manufacture or at the point of use.

[0096] In the method of using the compositions described herein, the compositions are generally contacted with the device structure for a sufficient time, for example, about 3 minutes to about 60 minutes, preferably about 5 minutes to about 20 minutes, in a batch process, and about 20 seconds to about 5 minutes, preferably about 30 seconds to about 3 minutes, in a single water process. In the method of using the compositions described herein, the compositions are generally contacted with the device structure at a temperature ranging from about 10°C to about 80°C, preferably about 20°C to about 60°C. The contact times and temperatures are exemplary, and any other suitable time and temperature conditions that are effective to achieve the required removal selectivity may be employed. One advantage of the compositions according to the present invention is that the SiGe / Si etch rate has a low temperature dependency. In particular, the SiGe etch rate and the SiGe / Si etch rate are still very high even at temperatures below 30°C, so that the substrate may be treated at room temperature.

[0097] Following achievement of the desired etching effect, the composition can be easily removed from the previously applied microelectronic device, for example, by rinsing, washing, or other removal step(s) as may be desired and effective in a given end application of the composition of the present invention. For example, the device may be rinsed with a rinse solution comprising deionized water, an organic solvent, and / or dried (e.g., spin-dried, N2, steam-dried, etc.).

[0098] It may be useful to rinse the blanket wafer surface with an aqueous solution containing 0.1% to 1% by weight of HF at room temperature for about 30 s, then immerse in UPW for 2 to 3 s and dry with compressed air. However, by using the composition according to the invention, it is possible and preferred to omit such pretreatment with HF.

[0099] The etching compositions described herein may be advantageously used to selectively etch SiGe layers in the presence of Si layers, and especially in the presence of silicon oxide layers.

[0100] The etching compositions described herein may be advantageously used in a method for selectively removing a silicon germanium alloy layer from a surface of a microelectronic device relative to a Si layer and preferably a silicon oxide layer, the method comprising the steps of: (a) providing a microelectronic device surface comprising a silicon germanium alloy layer and a Si layer and a layer comprising or consisting of silicon oxide; (b) providing the composition; and (c) contacting the surface with a composition for a time and at a temperature effective to selectively remove the silicon-germanium alloy layer relative to a Si layer and a layer comprising or consisting of silicon oxide. Includes.

[0101] Preferably, the SiGe etch rate of the composition according to the invention is 200 A / min or more, more preferably 300 A / min or more. Preferably, the Si etch rate of the composition according to the invention is 2 A / min or less, more preferably 1 A / min or less. Preferably, the SiO x The etch rates of SiN and SiON are 2 A / min or less, more preferably 1 A / min or less. Preferably, the etch rate of the silicon-germanium layer is at least 500 times faster than the etch rate of the Si layer (SiGe / Si selectivity), preferably 750 times, even more preferably 1000 times, even more preferably 2000 times, and most preferably 5000 times faster.

[0102] The etching compositions described herein may be advantageously used in methods of manufacturing semiconductor devices, including the selective removal of silicon germanium relative to Si and silicon oxide materials from surfaces of microelectronic devices.

[0103] All percentages, ppm or equivalent amounts refer to weight relative to the total weight of the respective composition unless otherwise indicated. All cited documents are incorporated herein by reference.

[0104] The following examples are intended to explain the invention in more detail without limiting its scope. EXAMPLES

[0105] The following substrate was used: SALSA III by IMEC, shown diagrammatically in Figure 3. The substrate comprises several stacked SiGe and Si layers. The SALSA3 layers are, from top to bottom: SiO2(50nm)-SiN(50nm)-SiO2(5nm)-Si(25nm)-SiGe(25nm)-Si(20nm)-SiGe(20nm)-Si(15nm)-SiGe(15nm)-Si(10nm)-SiGe(10nm)-Si(5nm)-SiGe(5nm)-Si <100> The wafers (approximately 0.70 mm) were constructed. All SiGe layers contained 25% germanium by mass. The Si layers consisted of crystalline Si.

[0106] The following materials were used with electronic grade purity: H2O2 (31%) ·NH4F ·DL-Tartaric acid Citric acid Sulfynol® 104 (available from Evonik) [ka] (3-Acrylamidepropyl)-trimethylammonium chloride Diethylenetriaminepentaacetic acid (DTPA) Ethylenediaminetetraacetic acid (EDTA) Hexamethylenetetramine

[0107] All amounts of compounds in the compositions are absolute amounts in the total mixture, ie, excluding water.

[0108] Etching bath preparation: The etching bath vessel was set at 24° C.+ / -0.5° C. The different components were mixed in the following order: water, NH4F, Surfynol 104, (3-acrylamidopropyl)-trimethylammonium chloride, DTPA or EDTA, acid, NH4OH and H2O2.

[0109] etching: After all components were mixed, the coupon containing the microstructures was inserted into the bath for 60 seconds. After etching, the coupon was rinsed with UPW and dried with compressed air.

[0110] Example 1 The compositions listed in Table 1a were prepared.

[0111] [Table 1]

[0112] The pH was adjusted to 6.1 by adding NH4OH (if necessary).

[0113] The etching rates (Å / min) were determined by TEM as a function of the lateral etching depth of the top SiGe25 and Si layers. The results are shown in Table 1b and the substrates etched with the compositions according to examples 1.1 and 1.2 are shown in Figures 1 and 2, respectively.

[0114] [Table 2]

[0115] Table 1b and Figure 1 show that Example 1.2 has no lateral loss of SiO2. Even though the SiGe etch rate is much lower, the overall selectivity of SiGe to Si or SiO2 is significantly increased.

[0116] Example 2 Example 1 was repeated with the compositions listed in Table 2a and the results are shown in Table 2b. The etching rate was determined by ellipsometry, comparing the layer thickness before and after etching.

[0117] [Table 3]

[0118] [Table 4]

[0119] Table 2b shows that (3-acrylamidopropyl)-trimethylammonium chloride used in Examples 2.1 and 2.2 has a stronger inhibitory effect on lateral loss of SiO2 compared to hexamethylenetetramine in Example 2.3. DTPA further reduces the etching rate of SiO2 compared to EDTA.

[0120] Example 3 Several bath stabilizers were tested.

[0121] The compositions listed in Table 3a were prepared. The etching rates were determined by ellipsometry, comparing the layer thickness before and after etching. The etching rates were determined after 0, 1, 2, 5, and 12 days as described in Example 1. The etching rates of SiGe25 are shown in Table 3b. No significant effect was observed on the etching rates of Si and SiO2.

[0122] [Table 5]

[0123] [Table 6]

[0124] Table 3b shows that the etching composition containing tartaric acid (Example 3.1) did not show a significant decrease in the SiGe25 etch rate over time. In contrast, the SiGe25 etch rates of the compositions containing citric acid, acetic acid, and phosphoric acid decreased significantly.

Claims

1. 1. A composition for selectively etching a silicon germanium alloy (SiGe) layer in the presence of a silicon layer, comprising: (a) 1 to 10% by weight of an oxidizing agent; (b) an etching solution containing 1 to 14 mass % of a fluoride ion source; (c) 0.001 to 3% by mass of formula S1 【Chemistry 1】 A selectivity enhancer represented by the formula: (d) 0.001 to 3 mass% of formula S31 【Chemistry 2】 an additional selectivity enhancer represented by and (e) Water Including, During the ceremony, R Ｓ１ , X Ｓ -OH and Y Ｓ -(CO)-OH; R Ｓ２ (i) R Ｓ１ , (ii) H, (iii) C １ ~C １０ alkyl, (iv) C １ ~C １０ alkenyl, (v) C １ ~C １０ Alkynyl, and (vi) -X Ｓ１ -(O-C ２ H ３ R Ｓ６ ) ｍ -OR Ｓ６ is selected from R Ｓ６ is H and C １ ~C ６ alkyl, R Ｓ３１ , R Ｓ３２ , R Ｓ３３ is C １ ~C ６ independently selected from alkyl, R Ｓ３４ , R Ｓ３５ , R Ｓ３６ is H and C １ ~C ６ independently selected from alkyl, X Ｓ is a linear or branched C １ ~C １０ Alkanediyl, linear or branched C ２ ~C １０ Alkenyl, linear or branched C ２ ~C １０ Alkynediyl, and -X Ｓ１ -(O-C ２ H ３ R Ｓ６ ) ｍ - selected from Y Ｓ is a chemical bond and X Ｓ is selected from X Ｓ１ is C １ ~C ６ It is an alkanediyl, X Ｓ３１ is C １ ~C ６ Alkanediyl and -X Ｓ１ -(O-C ２ H ３ R Ｓ６ ) ｍ - selected from The composition wherein m is an integer from 1 to 10.

2. The composition according to claim 1, wherein the oxidizing agent is selected from peroxides, preferably hydrogen peroxide.

3. 3. The composition according to claim 1 or 2, wherein the etching solution is selected from hydrogen fluoride, ammonium fluoride, ammonium bifluoride, triethanolammonium fluoride, diglycolammonium fluoride, methyldiethanolammonium fluoride, tetramethylammonium fluoride, triethylamine tri-hydrofluoride, fluoroboric acid, tetrafluoroboric acid, ammonium tetrafluoroborate, fluoroacetic acid, ammonium fluoroacetate, trifluoroacetic acid, fluorosilicic acid, ammonium fluorosilicate, tetrabutylammonium tetrafluoroborate, and mixtures thereof, preferably hydrogen fluoride.

4. The selectivity enhancer is (a) R Ｓ１ Is X Ｓ In the case of —OH, 0.0005 to 0.02% by mass, preferably 0.001 to 0.005% by mass, or (b) R Ｓ１ Is Y Ｓ In the case of --(CO)--OH, 0.1 to 3 mass %, preferably 0.5 to 2 mass % The composition of claim 1 or 2, wherein

5. R Ｓ１ Is X Ｓ -OH and X Ｓ C １ ~C ８ Alkanediyl, preferably C １ ~C ６ The composition according to claim 1 or 2, which is an alkane-1,1-diyl.

6. The selectivity enhancer has the formula S2: 【Chemistry 3】 (In the formula, R Ｓ１１ , R Ｓ２１ is C １ ~C ６ independently selected from alkyl, preferably ethyl, propyl, butyl, pentyl and hexyl; R Ｓ１２ , R Ｓ２２ is H and C １ ~C １０ alkyl, preferably H, methyl or ethyl; The composition according to claim 5 , wherein the compound is represented by the formula:

7. The first selectivity enhancer is represented by the formula S3 【Chemistry 4】 or, if the first selectivity enhancer is a compound represented by formula S2, the compound further comprises a second acetylenic compound represented by formula S3.

8. R Ｓ３１ , R Ｓ３２ , R Ｓ３３ is independently selected from methyl, ethyl, propyl, and butyl; R Ｓ３４ , R Ｓ３５ , R Ｓ３６ is independently H or selected from methyl, ethyl, propyl, and butyl; X Ｓ３１ is methanediyl, ethanediyl, propanediyl, butanediyl, and -X Ｓ１ -(O-C ２ H ３ R Ｓ６ ) ｍ - selected from R Ｓ６ is selected from H, or methyl and ethyl; X Ｓ１ is methanediyl, ethanediyl, propanediyl, butanediyl, m is an integer from 1 to 6; The composition according to claim 1 or 2.

9. R Ｓ３１ , R Ｓ３２ , R Ｓ３３ is independently selected from methyl and ethyl; R Ｓ３４ , R Ｓ３５ , R Ｓ３６ are independently H or methyl; X Ｓ３１ is methanediyl, ethane-1,2-diyl, propane-1,3-diyl, or butane-1,4-diyl, X Ｓ１ is methanediyl, ethane-1,2-diyl, propane-1,3-diyl, or butane-1,4-diyl, m is an integer from 1 to 6; The composition according to claim 1 or 2.

10. The second selectivity enhancer is represented by the formula S32 【Chemistry 5】 A compound represented by the formula: During the ceremony, R Ｓ３１ , R Ｓ３２ , R Ｓ３３ is independently selected from methyl, ethyl, propyl, or butyl; X Ｓ３１ The composition according to claim 1 or 2, wherein is selected from methanediyl, ethanediyl, propanediyl, and butanediyl.

11. The composition of claim 1 or 2, wherein the additional selectivity enhancer is present in an amount of from 0.005 to 2 wt %, preferably from 0.05 to 1 wt %.

12. 3. The composition according to claim 1, further comprising an organic acid selected from hydroxycarboxylic acids, in particular dihydroxydicarboxylic acids.

13. 10. Use of the composition of claim 1 for selectively etching a SiGe layer in the presence of a silicon layer and optionally a silicon oxide layer.

14. A method for selectively removing a silicon germanium layer from a surface of a microelectronic device relative to a silicon layer and optionally a silicon oxide layer, comprising the steps of: (a) providing a microelectronic device surface comprising a silicon germanium layer and a silicon layer and an optional silicon oxide layer; (b) providing a composition according to claim 1; and (c) contacting the surface with the composition for a time and at a temperature effective to selectively remove the silicon-germanium layer relative to the Si layer and any silicon oxide layer. The method includes:

15. 15. A method for manufacturing a semiconductor device, comprising the step of selectively removing a silicon germanium layer from a surface of a microelectronic device relative to a silicon layer and optionally a silicon oxide layer according to claim 14.

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