Use of composition for selectively etching silicon and method for selectively etching silicon

Abstract

The present invention relates to the use of a composition for selectively etching a silicon layer in the presence of an n-doped silicon layer at a temperature of from 10 DEG C to 50 DEG C, the composition comprising: (a) from 0.1% to 15% by weight of a selective enhancer selected from the group consisting of C1 to C20 primary alkylamines, C1 to C20 secondary alkylamines, C1 to C20 primary alkanolamines and C1 to C20 secondary alkanolamines; (b) water; wherein the n-doped silicon has a content of a Group 13 or Group 15 element of from 1016 cm <-3 > to 1022 cm <-3 >, preferably from 1017 cm <-3 > to 1021 cm <-3 >, most preferably from 1018 cm <-3 > to 1020 cm <-3 >.

Description

[0001] This application claims priority to European patent application No. 22200148.9 filed on October 6, 2022, the disclosure of which is hereby incorporated by reference in its entirety as if fully set forth herein.

[0002] The present invention relates to the use of a composition for selectively etching silicon relative to etching a material containing n-doped silicon at the surface of a microelectronic device substrate, and a method for selectively etching silicon relative to etching a material containing n-doped silicon at the surface of a microelectronic device substrate. Background Art

[0003] The steps of preparing certain microelectronic devices (e.g., integrated circuits) may include selectively removing silicon (Si) material from surfaces containing Si in combination with silicon doped with phosphorus (Si:P). The introduction of boron or phosphorus has important implications for the electronic characteristics of the Si structure, but does not affect the Si structure up to 10 18 -10 19 Atom / cm 3 Alkaline etching with a concentration of . Beyond this point, the etching rate decreases for both types of dopants. Interestingly, p-type doping (introduction of boron, Si: B) leads to increased alkaline etching of Si(111) compared to n-type (introduction of phosphorus, Si: P) doping of Si(111) (B. Gokce et al., J. Vac. Sci. Technol. [Vacuum Science and Technology Magazine] A 30, 040603 (2012); DOI: 10.1116 / 1.4721329).

[0004] The decrease in etch rate with increasing phosphorus concentration is less pronounced than with boron (H. Seidel et al., J. Electrochem. Soc. [Journal of the Electrochemical Society] 137 (1990), 3626). Some experiments have shown that selectivities of less than 5 for polysilicon over polysilicon:P can be achieved under standard alkaline conditions of TMAH at 55°C or 30°C. Under these conditions, polysilicon and polysilicon:P (P concentration of 7.10 19 Atom / cm 3 ) are similar. This is consistent with the literature, which reports that only when the P concentration exceeds 10 19 Atom / cm 3 The polysilicon:P etch rate only decreases with alkaline etchants when the polysilicon:P etch rate decreases with alkaline etchants. Therefore, TMAH does not allow for selective removal of polysilicon over phosphorus-doped polysilicon. A selectivity of at least 10:1, preferably 20:1, is required.

[0005] US2022 / 298417 A1 discloses an etching solution suitable for selectively removing polysilicon from a microelectronic device compared to p-doped silicon, the etching solution comprising water; at least one of NH4OH or quaternary ammonium hydroxide; at least one compound selected from benzoquinone; quinoline (or its derivatives); unsubstituted or substituted C 6-20 Fatty acid; C 4-12 alkylamines; and polyalkyleneimines; optionally at least one water-miscible organic solvent; and optionally at least one compound selected from the group consisting of alkanolamines and polyamines, and mixtures thereof.

[0006] Prior art solutions do not meet all requirements because they have at least one of the following drawbacks:

[0007] (a) Too low a Si / Si:P selectivity to allow removal of one or more Si layers without attacking the n-doped silicon layer;

[0008] (b) too low a Si etch rate, which results in a long time being required to completely remove one or more silicon layers; or

[0009] (c) Excessively high n-doped silicon etching rates, in particular Si:P etching rates, which result in removal of one or more n-doped silicon layers on top of one or more silicon layers.

[0010] It is therefore an object of the present invention to increase the selectivity of silicon to n-doped silicon, in particular the selectivity of Si to Si / Si:P, without reducing the etching rate relative to Si too much. Summary of the invention

[0011] It has now been found that the use of primary or secondary amines or primary or secondary alkanolamines significantly and selectively increases the silicon / doped silicon selectivity, since the etching rate of silicon layers, in particular crystalline silicon layers, polycrystalline silicon layers or amorphous silicon layers, is much lower than the etching rate of n-doped silicon layers.

[0012] Therefore, one embodiment of the present invention is the use of a composition for selectively etching a silicon layer in the presence of an n-doped silicon layer at a temperature of 10° C. to 50° C., the composition comprising:

[0013] (a) 0.1% to 15% by weight of a selectivity enhancer selected from C1 to C 20 Primary alkylamines, C1 to C 20 Secondary alkylamines, C1 to C 20 Primary alkanolamines and C1 to C 20 Secondary alkanolamines;

[0014] (b) water;

[0015] The n-doped silicon has 10 16 cm -3 Up to 10 22 cm -3 , preferably 10 17 cm -3 Up to 10 21 cm -3 , most preferably 10 18 cm -3 Up to 10 20 cm -3 The content of Group 13 or Group 15 elements.

[0016] It is particularly surprising that the etching composition according to the invention is suitable for allowing very controlled and selective etching of layers comprising or consisting of elemental silicon (Si), preferably amorphous silicon (aSi) or crystalline silicon, while at the same time not damaging or not significantly damaging layers comprising or consisting of silicon doped with an element of Group 15, in particular phosphorus (Si:P).

[0017] Another embodiment of the present invention is a method of selectively removing a silicon layer relative to an n-doped silicon layer from a surface of a microelectronic device, the method comprising:

[0018] (a) providing a microelectronic device surface comprising the silicon layer and the n-doped silicon layer, wherein the n-doped silicon layer has 10 16 cm -3 Up to 10 22 cm -3 The content of Group 13 or Group 15 elements;

[0019] (b) providing an etching composition, the etching composition comprising:

[0020] (i) 0.1% to 15% by weight of a selectivity enhancer selected from C1 to C 20 Primary alkylamines, C1 to C 20 Secondary alkylamines, C1 to C 20 Primary alkanolamines and C1 to C 20 secondary alkanolamines; and

[0021] (ii) water;

[0022] (c) contacting the surface with the composition at a temperature of 10° C. to 50° C. for a time effective to selectively remove the silicon layer relative to the n-doped silicon layer. DETAILED DESCRIPTION

[0023] The purpose of the etching composition is to etch a silicon (Si) layer in the presence of an n-doped silicon layer.

[0024] The composition used in the subject invention comprises 0.1% to 15% by weight of C1 to C 20 A primary alkylamine or a secondary alkylamine or a C1 to C 20 primary or secondary alkanolamine; and water. It is used in a temperature range of 10°C to 50°C in a mixture having 10 16 cm -3 Up to 10 22 cm -3 , preferably 10 17 cm -3 Up to 10 21 cm -3 , most preferably 10 18 cm -3 Up to 10 20 cm -3 In the presence of an n-doped silicon layer having a content of a Group 13 or Group 15 element, the silicon layer is selectively etched.

[0025] definition

[0026] As used herein, a "primary amine" is an amine that contains at least one primary amine functional group. As used herein, a "secondary amine" is an amine that contains at least one secondary amine functional group but does not contain a primary amine functional group. As used herein, a "tertiary amine" is an amine that contains at least one tertiary amine functional group but does not contain a secondary amine functional group or a primary amine functional group.

[0027] As used herein, a "silicon layer" or "Si layer" is a layer consisting essentially of elemental silicon, preferably of elemental silicon. It particularly includes, but is not limited to, a layer consisting of amorphous silicon, polycrystalline silicon or (single crystal) silicon. The etching composition is particularly useful when etching silicon, in particular amorphous silicon (aSi), in the presence of Si:P or Si:As. The term "essentially consisting of silicon" means that the silicon content in the layer is greater than 90% by weight, preferably greater than 95% by weight, even more preferably greater than 98% by weight. It is particularly preferred that the silicon layer does not contain any other elements besides silicon. Preferably, the doping element content of the silicon layer is less than 0.1% by weight, preferably less than 0.01% by weight, more preferably less than 0.001% by weight. Most preferably, the silicon layer does not contain other elements besides silicon.

[0028] As used herein, a "doped silicon" layer corresponds to a layer comprising or consisting of silicon doped with a Group 15 element as known in the art. The n-doped silicon layer typically has 10 16 cm -3 Up to 10 22 cm -3 , most preferably 10 18 cm -3 Up to 10 20 cm -3The content of the Group 13 or Group 15 element is determined by the Si:P ratio. Typical doping elements are phosphorus (Si:P) and arsenic (Si:As), but are not limited thereto. N-doping with phosphorus (Si:P) is particularly preferred.

[0029] As used herein, "selective etching" (or "selective etching rate") preferably means that after applying the composition according to the invention to a layer comprising or consisting of a first material (in this case Si, most particularly aSi) in the presence of a layer comprising or consisting of a second material (in this case n-doped silicon, in particular Si:P), the etching rate of the composition for etching the first layer is at least 30 times, preferably at least 50 times, even more preferably at least 100 times, most preferably at least 150 times the etching rate of the composition for etching the second layer. Depending on the substrate to be etched, other layers like SiO x , SiON or SiN should not be damaged.

[0030] As used herein, a "layer" means a portion of a substrate that is individually disposed on a surface of the substrate and has a distinguishable composition relative to adjacent layers.

[0031] As used herein, "chemical bond" means that the corresponding moieties do not exist but the adjacent moieties are bridged so as to form a direct chemical bond between these adjacent moieties. For example, if in molecule ABC moiety B is a chemical bond, then adjacent moieties A and C together form a group AC.

[0032] The term "C x " means that the corresponding group contains x number of C atoms. The term "C x To C y "Alkyl" means an alkyl group having a number of x to y carbon atoms, and unless specifically specified otherwise, includes unsubstituted straight chain, branched chain and cyclic alkyl groups. As used herein, "alkanediyl" refers to a diradical of a straight chain, branched chain or cyclic alkane or a combination thereof.

[0033] All percentages, ppm or similar values ​​refer to weight relative to the total weight of the corresponding composition, unless otherwise indicated.The terms "wt %" and "% by weight" are used synonymously herein.

[0034] All cited documents are incorporated herein by reference.

[0035] Si Selectivity Enhancer

[0036] It has been found that 0.1% to 15% by weight of a compound selected from C1 to C 20 Primary or secondary alkylamine and C1 to C 20The selectivity enhancer of primary or secondary alkanolamines selectively etches silicon layers, preferably aSi, while the etching rate of layers containing n-doped silicon, preferably phosphorus-doped silicon or consisting of the same is suppressed, which results in an a-Si / Si:X (X=P, As) selectivity higher than 10 or even higher than 20.

[0037] In a preferred embodiment, the composition comprises C1 to C 10 Primary amine or C1 to C 10 Primary alkanolamines.

[0038] In another preferred embodiment, an alkylamine having the formula E1 is used

[0039]

[0040] Where X E1 , X E1 and X E1 Independently selected from C2-C6 alkanediyl.

[0041] Preferably, X E1 , X E2 and X E3 Can be selected from ethane-1,1-diyl and ethane-1,2-diyl. In another preferred embodiment, X E1 , X E1 , X E1 Can be selected from propane-1,1-diyl, butane-1,1-diyl, pentane-1,1-diyl, and hexane-1,1-diyl. In yet another preferred embodiment, X S Can be selected from propane-2,2-diyl, butane-2,2-diyl, pentane-2,2-diyl, and hexane-2,2-diyl. In yet another preferred embodiment, X E1 , X E2 , and X E3 Can be selected from ethane-1-2-diyl, butane-1,2-diyl, pentane-1,2-diyl, and hexane-1,2-diyl. In yet another preferred embodiment, X S It may be selected from propane-1,3-diyl, butane-1,3-diyl, pentane-1,3-diyl, and hexane-1,3-diyl. Particularly preferred groups X E1 , X E2 and X E3 It is ethane-1,2-diyl, propane-1,3-diyl, propane-1,2-diyl or a divalent N,N-piperazine(1,4-diazacyclohexane) group.

[0042] In yet another preferred embodiment, the alkanolamine is a compound having formula E2a or E2b

[0043]

[0044] Used, where X E1 , X E1 , X E1 is independently selected from C2-C6 alkanediyl. Preferably, X E1 , X E2 and X E3 may have the meanings described above in relation to formula E1.

[0045] Particularly preferred selectivity enhancers are ethanolamine, propanolamine, tris-(2-aminoethyl)amine (TREN), tris-(3-aminopropyl)amine and 1-(2-aminoethyl)piperazine.

[0046] The selective enhancer may be present in an amount of about 0.1% to about 15% by weight. If the amount is too low, the enhancement effect is too poor. Further increases in concentration are technically feasible but do not make sense for commercial reasons. Preferred concentrations are about 2% to about 12% by weight, even more preferably about 3% to about 10% by weight. The optimal concentration window is from 4% to 7% by weight.

[0047] Compositions according to the invention may comprise one or more of the selective enhancers described herein.

[0048] water

[0049] The etching compositions developed by the present invention are water-based and therefore contain water. Water has several functions, such as dissolving one or more components in the composition, as a carrier of the components, as an auxiliary agent for removing residues, as a viscosity modifier for the composition, and as a diluent. Preferably, the water used in the composition is deionized (DI) water. The scope of water described in the next paragraph includes all water from any source in the composition.

[0050] For most applications, the weight percentage of water in the composition will exist within a range having a starting point and an end point selected from the following numerical group: 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 92, 94, 96. Examples of ranges of water that can be used in the composition include, for example, from about 45% to about 96% by weight, or from about 50% to about 94% by weight of water; or from about 60% to about 96% 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 96% by weight, or from about 90% to about 96% by weight of water. Still other preferred embodiments of the present invention may include water in an amount to achieve the desired weight percentages of the other ingredients.

[0051] Organic solvents

[0052] The etching composition may optionally contain one or more water-miscible organic solvents.

[0053] Examples of water-miscible organic solvents that can be employed are ethylene glycol, propylene glycol, 1,4-butylene glycol, glycerine, tripropylene glycol methyl ether, propylene glycol propyl ether, diethylene glycol n-butyl ether (BDG), dipropylene glycol methyl ether (DPM) hexyloxypropylamine, poly(oxyethylene) diamine, dimethyl sulfoxide (DMSO), tetrahydrofurfuryl alcohol, glycerine, alcohol, sulfolane, sulfoxide, ethanolamine, 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, for example, ethylene glycol or propylene glycol, and triols, such as, for example, glycerine.

[0054] For most applications, the amount of water-miscible organic solvent in the composition can be in a range having a starting point and an ending point selected from the following weight percentage list: 0.5, 1, 5, 7, 10, 12, 15, 20, 25, 29, 30, 33, 35, 40, 44, 49.5, 50. Examples of such ranges for solvent include from about 0.5% to about 50% by weight of the composition; or from about 1% to about 45% by weight; or from about 1% to about 40% by weight; or from about 0.5% to about 30% by weight; or from about 1% to about 30% by weight; or from about 5% to about 30% by weight; or from about 5% to about 20% by weight; or from about 7% to about 20% by weight, or from about 10% to about 30% by weight; or from about 15% to about 25% by weight.

[0055] In individual cases, the composition according to the present invention as defined herein may further comprise the following as optional additional components: one or more water-miscible organic solvents, which are preferably selected from the group consisting of tetrahydrofuran (THF), N-methylpyrrolidone (NMP), dimethylformamide (DMF), dimethyl sulfoxide (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.

[0056] In the context of the present invention, the term "water-miscible organic solvent" preferably means that an organic solvent that meets this requirement is miscible with water at least in a 1:1 (w / w) ratio at 20° C. and ambient pressure. Preferably, one or at least one water-miscible organic solvent (H) is sulfolane. In particular, preference is given to compositions according to the invention that do not comprise one or more water-miscible organic solvents.

[0057] In a preferred embodiment, the composition according to the present invention as defined herein is preferred, wherein 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, even more preferably from about 1% to about 6% by weight, based on the total weight of the composition.

[0058] In another preferred embodiment, the composition according to the present invention as defined herein is preferred, wherein the total amount of one or more water-miscible organic solvents is present in an amount from about 20% to about 55% by weight, preferably from about 25% to about 50% by weight, more preferably from about 30% to about 45% by weight, based on the total weight of the composition.

[0059] In yet another preferred embodiment, the composition according to the invention as defined herein comprises a first solvent selected from mono-, di- or tri-hydric C1 to C6 alkanols, preferably di- or tri-hydric C1 to C4 alkanols, most preferably ethylene glycol or glycerol. In yet another preferred embodiment, the composition according to the invention as defined herein comprises a second solvent selected from C1 to C6 alkanolamines, preferably C1 to C4 alkanolamines, most preferably ethanolamine or propanolamine.

[0060] In yet another preferred embodiment, the composition according to the invention as defined herein is an aqueous solution substantially free of organic solvents. 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, most preferably below the detection limit.

[0061] Chelating agents

[0062] The etching composition may optionally contain one or more chelating agents.

[0063] Preferred chelating agents are 1,2-cyclohexylidene 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, salicylideneaniline; 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-methylpyridine, lutidine, piperidine, piperazine, ethylamine, methylamine, isobutylamine, tert-butylamine, tributylamine, dipropylamine, dimethylamine, di Glycolamine, methyldiethanolamine, pyrrole, isoxazole, bipyridine, pyrimidine, pyrazine, pyridazine, quinoline, isoquinoline, indole, 1-methylimidazole, diisopropylamine, diisobutylamine, aniline, pentamethyldiethylenetriamine, acetoacetamide, ammonium carbamate, ammonium pyrrolidinedithiocarbamate, dimethyl malonate, methyl acetoacetate, N-methylacetoacetamide, 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.

[0064] The chelating agent may be 1,2-cyclohexylidene dinitrilotetraacetic acid (CDTA) or may include CDTA and one or more of the other chelating agents mentioned above.

[0065] Also preferred are compositions according to the invention as defined herein wherein the one or more chelating agents are present in an amount of 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.

[0066] Surfactants

[0067] The composition may further comprise one or more surfactants.

[0068] Preferred surfactants are selected from the group consisting of:

[0069] (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, PNAAS), perfluorooctanesulfonate, perfluorobutanesulfonate, perfluorononanoate and perfluorooctanoate; alkyl-aryl ether phosphates and alkyl ether phosphates;

[0070] (ii) a zwitterionic surfactant, preferably selected from the group consisting of (3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonic acid inner salt) ("CHAPS"), cocamidopropyl hydroxysultaine (CAS RN 68139-30-0), {[3-(dodecanoylamino)propyl](dimethyl)-ammonio}acetate, phosphatidylserine, phosphatidylethanolamine, phosphatidylcholine; and

[0071] (iii) a nonionic surfactant, which is preferably selected from the group consisting of glucoside alkyl ethers, glycerol alkyl ethers, cocamide ethanolamine and lauryl dimethyl amine oxide.

[0072] More preferred surfactants in the composition according to the invention are or comprise perfluorinated, N-substituted alkylsulfonamide ammonium salts.Preferred surfactants (E) in the composition according to the invention do not comprise metals or metal ions.

[0073] Also preferred are compositions according to the invention as defined herein wherein the one or more surfactants are present in an amount of 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.

[0074] Specific surfactants for use 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, sabinic 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, block copolymers based on ethylene oxide and propylene oxide (Newpole PE-68 (Sanyo), Pluronic L31, Pluronic 31R1, Pluronic L61, Pluronic F-127) (Dynol 607), polyoxypropylene sucrose ether (SN008S, Sanyo), tert-octylphenoxypolyethoxyethanol (Triton X100), 10-ethoxy-9,9-dimethyldecane-1-amine ( CF-32), polyoxyethylene (9) nonylphenyl ether, branched (IGEPAL CO-250), polyoxyethylene (40) nonylphenyl ether, branched (IGEPAL CO-890), polyoxyethylene sorbitan hexaoleate, polyoxyethylene sorbitan tetraoleate, polyethylene glycol sorbitan monooleate (Tween 80), sorbitan monooleate (Span 80), a combination of Tween 80 and Span 80, alcohol alkoxylates (e.g., Plurafac RA-20), alkyl-polyglucosides, ethyl perfluorobutyrate, 1,1,3,3,5,5-hexamethyl-1,5-bis[2-(5-norbornene-2-yl)ethyl]trisiloxane, monomeric octadecylsilane derivatives such as SIS6952.0 (Siliclad, Gelest), siloxane-modified polysilazanes such as PP1-SG10 Siliclad Glide 10 (Gayles), silicone-polyether copolymers such as Silwet L-77 (Setre Chemical Company), Silwet ECO spreader (Momentive), and ethoxylated fluorosurfactants ( FSO-100, FSN-100); cetyl trimethyl ammonium bromide (CTAB), heptadecafluorooctane sulfonic acid, tetraethyl ammonium, stearyl trimethyl ammonium chloride (Econol TMS-28, Sanyo Co., Ltd.), 4-(4-diethylaminophenylazo)-1-(4-nitrobenzyl) pyridinium bromide, cetyl pyridinium chloride monohydrate, benzalkonium chloride, benzethonium 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 ammonium p-toluenesulfonate, didodecyl dimethyl ammonium bromide, di(hydrogenated tallow) dimethyl ammonium chloride, tetraheptyl ammonium bromide, tetra(decyl) ammonium bromide, 336 and oxphenium bromide, guanidine hydrochloride (C(NH2)3Cl) or trifluoromethanesulfonates such as tetrabutylammonium trifluoromethanesulfonate, dimethyldioctadecyl ammonium chloride, dimethyldihexadecyl ammonium bromide and di(hydrogenated tallow)dimethylammonium chloride (e.g., Arquad 2HT-75, Akzo Nobel). Surfactants containing bromides, such as 1-hexadecyltrimethylammonium bromide.

[0075] In some embodiments, the compositions of the present invention will be free or substantially free of any or all of the surfactants listed above.

[0076] Corrosion Inhibitors

[0077] The etching compositions of the present invention may optionally contain one or more corrosion inhibitors. The corrosion inhibitor, if present, can protect the silicon-germanium from etching. Examples of corrosion inhibitors include aminocarboxylic acids, for example, triethylenetetraaminehexaacetic acid (TTHA), 1,3-diamino-2-hydroxypropane-N,N,N',N'-tetraacetic acid (DHPTA), methyliminodiacetic acid, propylenediaminetetraacetic acid, ethylenediaminetetraacetic acid (EDTA), butylenediaminetetraacetic 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); carboxylic acids such as capric acid, citric acid, tartaric acid, gluconic acid, sugar 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 include aminocarboxylic acids such as EDTA, 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. Most preferred is 8-hydroxyquinoline.

[0078] For most applications, the amount of corrosion inhibitor, such as aminocarboxylic acid, carboxylic acid, quinoline, or piperazine, etc. in the composition can be in a range having a starting point and an ending point selected from the following weight percentage list: 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 an amount from about 0.05 wt% to about 3 wt%, or from about 0.01 to about 3 wt%, or from about 0.1 wt% to about 5 wt%, or from about 0.1 wt% to about 15 wt%; or from about 0.1 wt% to about 10 wt%, or from about 0.5 wt.% to about 5 wt%, or from about 0.05 wt% to about 2 wt%, or from about 0.5 wt% to about 5 wt%.

[0079] In some embodiments, the compositions of the present invention will be free or substantially free of any or all of the corrosion inhibitors listed above, that is, the compositions will not contain any or all of the aminocarboxylic acids and / or carboxylic acids and / or quinolines and / or piperazines, etc. listed above.

[0080] Surface modifiers

[0081] The composition may further comprise a surface modifier selected from halogenated silanes, alkoxysilanes, oligo / poly-siloxanes, such as methyltrimethoxysilane, 3-aminopropyltriethoxysilane or cyclic, linear, branched siloxanes formed in aqueous solution thereof.

[0082] In a first embodiment, the surface modifier may be selected from siloxane compounds having the following formulas I to IV:

[0083]

[0084]

[0085] in

[0086] R 1 , R 2 are independently selected from H or C1 to C 10 alkyl,

[0087] n is 0, 1, or 2,

[0088] e, u, v are independently selected from integers from 0 to 5,

[0089] b, d, w are independently selected from integers from 0 to 6,

[0090] a, c, x are independently selected from integers from 1 to 22,

[0091] y is an integer from 1 to 5,

[0092] R 10 , R 12 are independently selected from H or C1 to C 10 Alkyl, and

[0093] R 11 Selected from H or C1 to C 10 alkyl.

[0094] In another preferred embodiment, a siloxane having the formula I is used, wherein R 1 , R 2 independently selected from H, methyl or ethyl, preferably methyl,

[0095] e is 0, 1 or 2, preferably 1,

[0096] b, d are 0, 1 or 2, preferably 0 or 1,

[0097] a, c are independently selected from integers from 0 to 10, preferably from 0 to 4,

[0098] R 10 , R 12 are independently selected from H, methyl or ethyl, preferably methyl, and

[0099] R 11 Selected from methyl or ethyl, preferably methyl.

[0100] In a preferred embodiment, a siloxane having Formula II may be used, wherein

[0101] R 1 , R 2 It is methyl,

[0102] e is 0, 1 or 2, preferably 1,

[0103] R 10 , R 12 Independently selected from methyl or ethyl, preferably methyl.

[0104] In yet another preferred embodiment, the siloxanes having formula III are those wherein

[0105] R 1 , R 2 is methyl or ethyl, preferably methyl,

[0106] u, v are 0 or 1, preferably 0,

[0107] w is 0 or 3, preferably 3,

[0108] x is an integer from 2 to 20, preferably from 5 to 15,

[0109] y is 1 or 2, preferably 1,

[0110] R 10 , R 12 are independently selected from methyl or ethyl, preferably methyl, and

[0111] R 11 Selected from H or methyl, preferably H.

[0112] In yet another preferred embodiment, at least one additive may be a cyclic siloxane having Formula IV, wherein

[0113] n is 1, and

[0114] R 1 , R 2 are the same or different and are selected from methyl, ethyl, propyl or butyl.

[0115] Siloxane compounds of the formulae I to IV are commercially available, for example, under the trade name Silwet TM and Tegopren TM get.

[0116] Additional specific embodiments of surface modifiers as described in WO 2019 / 086374, which is incorporated herein by reference, may be advantageously used.

[0117] The surface modifier may be used in a concentration range from about 0.001 wt % to about 1.0 wt %.

[0118] Composition

[0119] Other commonly known components such as dyes, chemical modifiers, microbicides, etc. may be included in the cleaning composition in conventional amounts to the extent that they do not adversely affect the performance of the composition, for example, up to about 1% or 5% or 10% by weight of the total composition.

[0120] Alternatively, the compositions of the present invention may be free or substantially free of any or all dyes, chemical modifiers, or microbicides.

[0121] 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 are dissolved in the water-based medium.

[0122] Typically, the pH of the composition may range from 8 to 14. In preferred embodiments, the pH of the etching composition is from about 9 to about 13, more preferably from about 10 to about 13, and most preferably from about 11 to about 12.5.

[0123] Preferably, the composition is substantially free of or free of any quaternary ammonium hydroxide,

[0124] and / or ammonium hydroxide.

[0125] Preferably, the composition is substantially free or free of any polyalkyleneimines, especially polyethyleneimines.

[0126] Preferably, the composition is substantially free or free of benzoquinone or derivatives of benzoquinone.

[0127] Preferably, the composition is substantially free or free of quinoline or quinoline derivatives.

[0128] Preferably, the composition contains substantially no or no unsubstituted or substituted C6-C 20 fatty acid.

[0129] In preferred embodiments, the composition consists essentially of or consists of:

[0130] (a) 0.1 to 15% by weight of a selectivity enhancer, particularly C2 to C 10 Primary alkylamine or C2 to C 10 Primary alkanolamines;

[0131] (b) 0% or 0.5% to 50% by weight of an organic solvent;

[0132] (c) 0% or 0.0001% to 3% by weight, in particular 0.0001% to about 1% by weight, more particularly 0.0005% to 0.5% by weight, even more particularly 0.001% to 0.01% by weight of surfactants;

[0133] (d) 0% or 0.01% to 3% by weight, in particular 0.01% to 3% by weight, more particularly 0.02% to 1% by weight, even more particularly 0.05% to 0.8% by weight of a chelating agent;

[0134] (e) Residue of water.

[0135] In preferred embodiments, the composition consists essentially of or consists of:

[0136] (a) 2 to 10% by weight of a selectivity enhancer, especially tris-(2-aminoethyl)amine;

[0137] (b) 0% by weight of organic solvent;

[0138] (c) 0% or 0.001% to 1% by weight of a surface modifier;

[0139] (d) 0% or 0.0001% to 3% by weight, in particular 0.0001% to about 1% by weight, more particularly 0.0005% to 0.5% by weight, even more particularly 0.001% to 0.01% by weight of surfactants;

[0140] (e) 0% or 0.01% to 3% by weight, in particular 0.01% to 3% by weight, more particularly 0.02% to 1% by weight, even more particularly 0.05% to 0.8% by weight of a chelating agent;

[0141] (f) Residue of water.

[0142] In preferred embodiments, the composition consists essentially of or consists of:

[0143] (a) 2 to 10% by weight of an amine of formula E1, in particular tris-(2-aminoethyl)amine;

[0144] (b) 2 to 25% by weight of one or more organic solvents, in particular ethylene glycol, propylene glycol, glycerol, or a combination thereof;

[0145] (c) 0% or 0.001% to 1% by weight of a surface modifier;

[0146] (d) 0% or 0.0001% to 3% by weight, in particular 0.0001% to about 1% by weight, more particularly 0.0005% to 0.5% by weight, even more particularly 0.001% to 0.01% by weight of surfactants;

[0147] (e) 0% or 0.01% to 3% by weight, in particular 0.01% to 3% by weight, more particularly 0.02% to 1% by weight, even more particularly 0.05% to 0.8% by weight of a chelating agent;

[0148] (f) Residue of water.

[0149] In preferred embodiments, the composition consists essentially of or consists of:

[0150] (a) 2 to 10% by weight of an amine of formula E1, in particular tris-(2-aminoethyl)amine;

[0151] (b) 5 to 25% by weight of a C2 to C6 polyol, in particular glycerol;

[0152] (c) 0% or 0.001% to 1% by weight of a surface modifier;

[0153] (d) 0% or 0.0001% to 3% by weight, in particular 0.0001% to about 1% by weight, more particularly 0.0005% to 0.5% by weight, even more particularly 0.001% to 0.01% by weight of surfactants;

[0154] (e) 0% or 0.01% to 3% by weight, in particular 0.01% to 3% by weight, more particularly 0.02% to 1% by weight, even more particularly 0.05% to 0.8% by weight of a chelating agent;

[0155] (f) Residue of water.

[0156] In preferred embodiments, the composition consists essentially of or consists of the selectivity enhancer and water.

[0157] In particularly preferred embodiments, the composition consists essentially of, or consists of, 1% to 12%, preferably 2% to 10%, most preferably 3% to 7% by weight of a selectivity enhancer, particularly a primary alkylamine, most particularly tris-(2-aminoethyl)amine, and water.

[0158] In another particularly preferred embodiment, the composition consists essentially of the selectivity enhancer, one or more organic solvents, and water.

[0159] In this context, "substantially" means that the content of any other compounds than the specifically mentioned compounds is below 1% by weight, preferably below 0.1% by weight, even more preferably below 0.01% by weight, most preferably below the detection limit.

[0160] Compositions according to the invention as defined herein are particularly preferred, wherein the composition consists of an amine of formula E1 and water, as defined herein and based on the examples.

[0161] application

[0162] In another aspect, there is provided a method of selectively removing a silicon layer relative to an n-doped silicon layer from a surface of a microelectronic device, the method comprising:

[0163] (a) providing a microelectronic device surface comprising the silicon layer and the n-doped silicon layer, wherein the n-doped silicon layer has 10 16 cm -3 Up to 10 22 cm -3 The content of Group 13 or Group 15 elements;

[0164] (b) providing an etching composition, the etching composition comprising:

[0165] (i) 0.1% to 15% by weight of a selectivity enhancer selected from C1 to C 20 Primary alkylamines, C1 to C 20 Secondary alkylamines, C1 to C 20 Primary alkanolamines and C1 to C 20 secondary alkanolamines; and

[0166] (ii) water;

[0167] (c) contacting the surface with the composition at a temperature of 10° C. to 50° C. for a time effective to selectively remove the silicon layer relative to the n-doped silicon layer.

[0168] In yet another aspect, a method is provided for selectively enhancing the etch rate of silicon relative to n-doped silicon in a microelectronic device, such as a composite semiconductor device, comprising silicon and n-doped silicon by etching the microelectronic device (composite semiconductor device) using a composition as described herein.

[0169] It will be appreciated that it is common practice to prepare a concentrated form of the composition to be diluted prior to use. For example, the composition may be manufactured in a more concentrated form and thereafter diluted with water, at least one oxidizing agent, or other components 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 to 1 part composition concentrate.

[0170] In the use of the compositions described herein, the compositions are typically contacted with the device structure for a sufficient time of about 1 minute to about 200 minutes, preferably about 5 minutes to about 60 minutes, at a temperature in the range of about 50° C. to about 90° C., preferably about 60° C. to about 80° C. Such contact times and temperatures are illustrative, and any other suitable time and temperature conditions effective to achieve the desired removal selectivity may be employed.

[0171] The etching ratio of silicon / doped silicon is found to be particularly favorable at low temperatures below 50° C., preferably below 45° C., even more preferably below 40° C., even more preferably below 34° C., even more preferably below 30° C. Etching at temperatures below 10° C. is generally possible, but is economically disadvantageous.

[0172] After achieving the desired etching behavior, the composition can be easily removed from the microelectronic device to which it has been previously applied, for example by rinsing, washing, or one or more other removal steps as may be desirable and effective in a given end-use application of the composition of the present invention. For example, the device can be rinsed with a rinse solution comprising deionized water, an organic solvent and / or dried (e.g., spin drying, N2, steam drying, etc.).

[0173] It may be useful to clean the blanket wafer surface (to remove oxide) with an aqueous solution containing about 0.1% to 5% by weight HF at room temperature for about 10 seconds to about 120 seconds.

[0174] Preferably, the silicon etching rate of the composition according to the invention is 2000 A / min or more, more preferably 3000 A / min or more. Preferably, the n-doped silicon, in particular Si:P etching rate of the composition according to the invention is 30 A / min or less, more preferably 25 A / min or less. Preferably, the etching rate of the layer containing silicon is at least 30 times faster than the etching rate of the n-doped silicon layer (silicon / doped silicon selectivity), preferably 50 times, even more preferably 80 times, even more preferably 120 times, most preferably more than 150 times.

[0175] The contacting step is followed by an optional rinsing step. The rinsing step may be performed by any suitable means, such as rinsing the substrate with deionized water by immersion or spraying techniques. In a preferred embodiment, the rinsing step may be performed using a mixture of deionized water and an organic solvent such as isopropanol.

[0176] The contacting step and optional rinsing step are followed by an optional drying step, which is performed by any suitable means, such as isopropyl alcohol (IPA) vapor drying, heating, or by centripetal force.

[0177] The etching compositions described herein may be advantageously used in a method for manufacturing a semiconductor device, the method comprising the step of selectively removing silicon from a surface of a microelectronic device relative to a phosphorus-doped silicon material described herein.

[0178] All percentages, ppm or similar values ​​refer to weight relative to the total weight of the corresponding composition, unless otherwise indicated. The terms "% by weight" and "wt%" are used synonymously herein. All cited documents are incorporated herein by reference.

[0179] The following examples shall further illustrate the present invention without limiting the scope of the present invention.

[0180] Examples

[0181] General procedures and substrates

[0182] The following substrates were used: blanket wafers containing polysilicon (500 nm polysilicon on 100 nm SiO2) and phosphorus-doped polysilicon blanket wafers (300 nm polysilicon on 100 nm SiO2 with 0.5 or 4.0 mΩcm).

[0183] All amounts given for compounds in the compositions are absolute amounts, ie, do not include the amount of water in the total mixture.

[0184] Etching bath preparation:

[0185] Prepare the etchant by adding the corresponding additives to deionized water. Transfer the etchant to a plastic beaker equipped with a thermostat.

[0186] Pre-etching:

[0187] UPW and 1 wt% hydrogen fluoride were loaded into two plastic beakers. Each test piece (Si:P, polysilicon) was pre-etched in 1 wt% hydrogen fluoride for 30 s, then immersed in UPW for 2-3 s and dried with compressed air.

[0188] Prepare polycrystalline silicon (Poly-Si) of about 2.5 cm × 2.5 cm and a phosphorus content of 7·10 19 cm -3 A silicon (Si:P) wafer coupon of phosphorus doped with 1% HF was prepared and rinsed with isopropyl alcohol and dried with a stream of nitrogen. Just before etching, the coupon was immersed in 1% aqueous HF in a plastic container for 1 minute, rinsed with DI water and added to the etchant as described below.

[0189] The etchant was set to a specified temperature of + / - 0.5°C. Once the temperature was reached, the polysilicon or Si:P wafer coupons were immersed in the etchant. Each coupon was etched for 0.5 to 2 minutes depending on the substrate thickness with stirring, followed by rinsing with DI water and drying. All experiments were performed under an argon atmosphere.

[0190] The resulting thickness is determined by spectroscopic ellipsometry.

[0191] Example 1

[0192] The compositions listed in Table 1 were prepared. The etching rate was determined by ellipsometry by comparing the layer thickness before and after etching. The results are also described in Table 1.

[0193] Table 1

[0194]

[0195]

[0196] TMAH = Tetramethylammonium hydroxide

[0197] DBU = 1,8-diazabicyclo[5.4.0]undec-7-ene

[0198] TREN = tris(2-aminoethyl)amine

[0199] Table 1 shows that at 55°C, all amine etches and strong bases like TMAH or DBU show low or moderate selectivity for polysilicon over polysilicon:P.

[0200] Compared to 55°C, the primary and secondary amine etchants ethanolamine, diethanolamine and TREN performed much better at 30°C, where selectivity increased by a factor of 10, while the selectivity of DBU remained roughly the same and the selectivity of triethanolamine (tertiary amine) and TMAH decreased even further. The selectivity increased from secondary to primary alkylamines and alkanolamines. The highest selectivity was observed in the case of an aqueous solution of TREN.

Claims

1. Use of a composition for selectively etching a silicon layer in the presence of an n-doped silicon layer at a temperature of 10° C. to 50° C., the composition comprising: (a) 0.1% to 15% by weight of a selectivity enhancer selected from C1 to C 20 Primary alkylamines, C1 to C 20 Secondary alkylamines, C1 to C 20 Primary alkanolamines and C1 to C 20 Secondary alkanolamines; (b) water; The n-doped silicon has 10 16 cm -3 Up to 10 22 cm -3 , preferably 10 17 cm -3 Up to 10 21 cm -3 , most preferably 10 18 cm -3 Up to 10 20 cm -3 The content of Group 13 or Group 15 elements.

2. The use according to claim 1, wherein The selectivity enhancer is C1 to C 10 Primary amine or C1 to C 10 Primary alkanolamines.

3. The use according to claim 1 or 2, wherein The selectivity enhancer is a compound having the formula E1 in X E1 , X E1 , X E1 Independently selected from C2-C6 alkanediyl.

4. The use according to claim 3, wherein X E1 Selected from methanediyl, ethane-1,2-diyl, propane-1,3-diyl, and propane-1,2-diyl.

5. The use according to claim 1, wherein The selectivity enhancer is a compound having formula E2a or E2b in X E1 , X E1 , X E1 Independently selected from C2-C6 alkanediyl.

6. The use according to claim 1, wherein The selectivity enhancer is selected from the group consisting of ethanolamine, propanolamine, tris-(2-aminoethyl)amine (TREN), tris-(3-aminopropyl)amine, and 1-(2-aminoethyl)piperazine.

7. Use according to any one of the preceding claims, further comprising a water-miscible organic solvent.

8. Use according to any one of the preceding claims, wherein The composition consists essentially of: (a) 0.1% to 15% by weight of the primary or secondary amine or primary or secondary alkanolamine; (b) 0 to 50% by weight of an organic solvent; (c) 0% to 3% by weight of a surfactant; (d) 0% to 3% by weight of a chelating agent; (e) Residue of water.

9. The use according to any one of the preceding claims, wherein The composition consists essentially of the selective enhancer and water.

10. The use described above, wherein the composition has a pH of 10 to 13, preferably 11 to 12.

5.

11. Use according to any one of the preceding claims for selectively etching a silicon layer in the presence of an n-doped silicon layer at a temperature of 20°C to 40°C.

12. A method for selectively removing a silicon layer relative to an n-doped silicon layer from a surface of a microelectronic device, the method comprising: (a) providing a microelectronic device surface comprising the silicon layer and the n-doped silicon layer, wherein the n-doped silicon layer has 10 16 cm -3 Up to 10 22 cm -3 The content of Group 13 or Group 15 elements; (b) providing an etching composition, the etching composition comprising: (i) 0.1% to 15% by weight of a selectivity enhancer selected from C1 to C 20 Primary alkylamines, C1 to C 20 Secondary alkylamines, C1 to C 20 Primary alkanolamines and C1 to C 20 secondary alkanolamines; and (ii) water; (c) contacting the surface with the composition at a temperature of 10° C. to 50° C. for a time effective to selectively remove the silicon layer relative to the n-doped silicon layer.

13. The method according to claim 12, wherein step (c) is performed at a temperature of 20°C to 40°C.

14. A method for manufacturing a semiconductor device, the method comprising the step of selectively removing silicon from the surface of a microelectronic device relative to a material containing phosphorus-doped silicon according to claim 12 or 13.

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