Silicon nitride film etching composition and etching method using the same

Abstract

The present invention relates to a silicon nitride film etching composition, a method of etching a silicon nitride film using the same, and a method of manufacturing a semiconductor device. Specifically, according to the present invention, a silicon nitride film can be etched with high selectivity over a silicon oxide film, and when applied to a high-temperature etching process and a semiconductor manufacturing process, not only does no precipitate occur, but also no abnormal growth in which the thickness of the silicon oxide film is increased, thus defects and reliability degradation can be minimized.

Description

TECHNICAL FIELD

[0001] The present application relates to a silicon nitride film etching composition, a method for etching a silicon nitride film using the same, and a method for manufacturing a semiconductor device. BACKGROUND

[0002] Silicon oxide films (SiO2) and silicon nitride films (SiN x ) are representative insulating films used in semiconductor manufacturing processes. Among them, silicon nitride films are used as a cap layer, a spacer layer, or a hard mask layer in semiconductor devices. Silicon oxide films and silicon nitride films can be used alone, or in a laminate of one or more layers of silicon oxide films and one or more layers of silicon nitride films.

[0003] For etching of a silicon nitride film, a phosphoric acid aqueous solution at a high temperature of about 160°C, which is composed of high-purity phosphoric acid and deionized water, is used. However, the etching selectivity of the silicon nitride film with respect to a silicon oxide film is low, at 30 or less, for the phosphoric acid aqueous solution, and thus it is difficult to apply to a laminated structure of a silicon nitride film and a silicon oxide film. In addition, a silicon nitride film etching composition containing phosphoric acid is continuously concentrated based on water evaporation at a high temperature, and thus the etching rate of a nitride film and an oxide film is affected, and thus pure water (deionized water) needs to be continuously supplied. However, even a slight change in the amount of the supplied pure water causes defects in the removal of the silicon nitride film.

[0004] In order to solve the problem and improve the etching selectivity of the silicon nitride film with respect to the silicon oxide film, a silicon nitride film etching composition formed by dissolving silicic acid in phosphoric acid can be used. However, the silicon nitride film etching composition has problems in that precipitates are generated when etching is performed, and an abnormal growth problem in which the thickness of the silicon oxide film is increased, and thus it is difficult to apply to a process.

[0005] In addition thereto, a method for controlling the etching selectivity using a silicon compound containing an oxygen atom directly bonded to silicon can be used, but the etching selectivity of the silicon nitride film with respect to the silicon oxide film is not high, and precipitates are still generated, and thus there is a need to develop an etching composition that does not generate precipitates and can etch a silicon nitride film at a high selectivity. SUMMARY

[0006] An embodiment of the present application aims to provide a silicon nitride film etching composition having a high etching selectivity with respect to a silicon nitride film.

[0007] Another embodiment of the present application aims to provide a stable silicon nitride film etching composition in which the etching speed and the change in the etching selectivity with respect to a silicon nitride film are small even if the etching process time is increased or reused.

[0008] Yet another embodiment of the present application aims to provide a silicon nitride film etching composition which does not generate precipitates when etching is performed.

[0009] Yet another embodiment of the present application aims to provide a method of etching a silicon nitride film using a silicon nitride film etching composition and a method of manufacturing a semiconductor device.

[0010] In one general aspect, a silicon nitride film etching composition includes: phosphoric acid; a silsesquioxane; and a balance of water.

[0011] In the silicon nitride film etching composition of one embodiment of the present application, the silsesquioxane can be a compound represented by the following Chemical Formula 1:

[0012] [Chemical Formula 1]

[0013] (R 1 SiO3 / 2) n

[0014] In the Chemical Formula 1,

[0015] n is an integer of 6, 8, 10, or 12;

[0016] R 1 each independently is hydrogen, a halogen group, a cyano group, a nitro group, a hydroxyl group, a C 1-20 alkyl group, a C 20 alkyl group, a C 20 cycloalkyl group, a C 20 heterocycloalkyl group, a C 20 heteroaryl group, a C 20 aryl group, a C 1-20 aminoalkyl group, or R 11 to R 14 each independently is hydrogen, a C 1-20 alkyl group, or a C 1-20 hydroxyalkyl group.

[0017] In the silicon nitride film etching composition of one embodiment of the present application, in the compound represented by the Chemical Formula 1, the n is an integer of 6 or 8, the R 1 each independently is a C 1-20 alkyl group, a C 1-20 aminoalkyl group, or the R 11 to R 14 each independently is hydrogen or a C 1-20 alkyl group.

[0018] In the silicon nitride film etching composition of one embodiment of the present application, in the compound represented by the Chemical Formula 1, the R1each independently is a C1-7 Alkyl, C 1-7 aminoalkyl or The R 11 To R 14 Each is independently hydrogen or C 1-7 alkyl.

[0019] In a silicon nitride film etching composition according to an embodiment of the present invention, in the compound represented by the chemical formula 1, at least one of R1 is... The remaining R1s are each independently C 1-7 Alkyl, C 1-7 aminoalkyl or The R 11 To R 14 Each is independently hydrogen or C 1-7 alkyl.

[0020] In a silicon nitride film etching composition according to an embodiment of the present invention, the composition comprises, relative to the total weight of the silicon nitride film etching composition, 60 to 95% by weight of the phosphoric acid, 0.01 to 5.00% by weight of the silsesquioxane, and the balance being water.

[0021] In one embodiment of the silicon nitride film etching composition of the present invention, an alcohol solvent may also be included.

[0022] In one embodiment of the silicon nitride film etching composition of the present invention, inorganic acids, their derivatives, or combinations thereof may also be included.

[0023] In one embodiment of the silicon nitride film etching composition of the present invention, ammonium compounds may also be included.

[0024] In a silicon nitride film etching composition according to an embodiment of the present invention, the etching selectivity ratio of silicon nitride film to silicon oxide film can be 500 or higher.

[0025] In a silicon nitride film etching composition according to an embodiment of the present invention, the etching rate of the silicon nitride film can be 20 to... The etching rate for silicon oxide films can be from 0 to...

[0026] In a silicon nitride film etching composition according to an embodiment of the present invention, the rate of reduction of the etching rate of the silicon nitride film after repeated etching processes satisfies the following relationship 1:

[0027] [Relation 1]

[0028] △ERD SiNx ≤1%

[0029] In relation 1,

[0030] △ERDSiNx The etching rate reduction rate is the etching rate relative to the initial etching rate of the silicon nitride film.

[0031] In another general aspect, there is provided a method of selectively etching a silicon nitride film over a silicon oxide film using the above-described silicon nitride film etching composition.

[0032] In another general aspect, there is provided a method of manufacturing a semiconductor device including an etching process using the above-described silicon nitride film etching composition.

[0033] Other features and aspects will be apparent from the following detailed description and the appended claims. DETAILED DESCRIPTION

[0034] Hereinafter, the silicon nitride film etching composition according to the present application will be described in detail. At this time, among the technical and scientific terms used, unless otherwise defined, it has the meaning commonly understood by one of ordinary skill in the art to which the present application pertains, and the description of well-known functions and configurations that can unnecessarily obscure the gist of the present application will be omitted in the following description.

[0035] The singular forms "a," "an," and "the" used in the present specification are intended to include the plural forms as well unless the context clearly indicates otherwise.

[0036] In addition, the units used in the present specification, for example, % or ratio, without special mention in the present specification, refer to weight % or weight ratio, and with respect to weight %, unless otherwise defined, refer to the weight % of each component in the composition in the entire composition.

[0037] In addition, the numerical ranges used in the present specification include: the lower limit value, the upper limit value, and all values within the range; increments logically derived from the form and width of the defined range; all double-limited values; and all possible combinations of the upper and lower limits of the numerical ranges defined in different forms. Unless otherwise defined in the specification of the present application, values outside the numerical range due to experimental error values or rounding are also included in the defined numerical range.

[0038] The term "comprise" in the present specification is an open description, and its meaning is equivalent to "have", "include", "possess", "characterized by", and the like, and does not exclude elements, materials, or processes not further listed.

[0039] The term "silsesquioxane" in the present specification is a compound including a siloxane structure composed of Si-O-Si bonds, and can be produced by hydrolytic polymerization using trialkoxysilane, tetraalkoxysilane, or trihalosilane, silicic acid, silica, or the like.

[0040] The term "etch selectivity (E SiNx / E SiO2 )" in the present specification means the ratio of the etching rate of the silicon nitride film (E SiNx ) to the etching rate of the silicon oxide film (E SiO2 ). In addition, in the case where the etching rate of the silicon oxide film is almost 0 or the value of the etch selectivity is large, it means that the silicon nitride film can be selectively etched.

[0041] The term "change in etch selectivity" in the present specification means, in the case where the etching process is repeated two or more times using the same silicon nitride film etching composition, the absolute value of the difference between the etch selectivity and the initial etch selectivity.

[0042] The term "etch rate drift (△ERD)" in the present specification means, in the case where the etching process is repeated two or more times using the same silicon nitride film etching composition, the rate of change of the etching rate with respect to the initial etching rate. In general, as the etching process is repeated, the etching ability, that is, the etching rate, shows a tendency to decrease, and thus the rate of decrease is defined, and the rate of change is also interpreted as the same meaning. Specifically, the above etch rate drift can be derived from the following Formula 1.

[0043] [Formula 1]

[0044] △ERD = [1 - {(etching rate when the etching process is repeated n times or more) / (initial etching rate)}] x 100

[0045] The term "alkyl group", "alkoxy group", or a substituent group including an alkyl group in the present specification includes linear and branched forms.

[0046] The term "cycloalkyl group" in the present specification means a monovalent group derived from a completely saturated and partially unsaturated hydrocarbon ring having 3 to 10 carbon atoms.

[0047] The term "heterocycloalkyl group" in the present specification is a monovalent cycloalkyl group derived from a monocyclic or polycyclic non-aromatic ring containing one or more atoms or functional groups selected from B, N, O, S, Se, -P(=O)-, -C(=O)-, Si, and P, and the like.

[0048] The term "aryl" in the present specification means a monovalent group derived from an aromatic hydrocarbon ring.

[0049] The term "heteroaryl" in the present specification means a monovalent group derived from an aromatic ring, and is a monovalent aryl group derived from a monocyclic or polycyclic aromatic ring containing one or more atoms or functional groups selected from B, N, O, S, Se, -P(=O)-, -C(=O)-, Si, and P.

[0050] The term "halogen group" or "halogen" in the present specification means a fluorine, chlorine, bromine, or iodine atom.

[0051] The term "aminoalkyl" in the present specification means an alkyl group containing an amino group (*-NR'R"). At this time, each of R' and R" is independently hydrogen or a C 1-20 alkyl group.

[0052] The term "hydroxyalkyl" in the present specification means an alkyl group containing a hydroxy group (*-OH).

[0053] As is well known, a silicon nitride film and a silicon oxide film are representative insulating films used in a semiconductor manufacturing process. A silicon nitride film is mainly formed by a chemical vapor deposition (CVD) process in which a thin film is laminated on the surface of a silicon oxide film, a polysilicon film, and a silicon wafer, and the silicon nitride film thus formed can be removed by etching.

[0054] A conventional wet etching has a problem in that the etching selectivity of a silicon nitride film with respect to a silicon oxide film decreases and the etching selectivity changes when the etching solution is used repeatedly. In addition, there is a problem in that an etching process produces an exudate and the thickness of a silicon oxide film increases.

[0055] As a result, the inventors have intensively studied a silicon nitride film etching composition which solves the above problems and has a further improved etching selectivity. As a result, it has been found that when a phosphoric acid-based etching solution composition including a silsesquioxane as an additive is used, the etching selectivity of a silicon nitride film with respect to a silicon oxide film is significantly improved, and the production of an exudate is also inhibited, and excellent effects are exhibited in reducing abnormal growth of a surrounding film including a silicon oxide film.

[0056] In addition, it has been found that the silicon nitride film etching composition according to the present application exhibits high selectivity with respect to a silicon nitride film of a silicon oxide film, and also exhibits high stability when etching at a high temperature of 150°C or more, and thus maintains the etching rate and etching selectivity with respect to a silicon nitride film for a long time even when the treatment time and the number of treatments increase, thereby completing the present application.

[0057] Hereinafter, the silicon nitride film etching composition according to the present application will be described in detail.

[0058] The silicon nitride film etching composition of one embodiment of the present application is an etching composition having a high selectivity ratio to a silicon nitride film with respect to a silicon oxide film, and can include phosphoric acid; a silsesquioxane; and a balance of water.

[0059] In the silicon nitride film etching composition of one embodiment of the present application, the silsesquioxane can be a compound represented by the following Chemical Formula 1:

[0060] [Chemical Formula 1]

[0061] (R 1 SiO3 / 2) n

[0062] In the Chemical Formula 1,

[0063] n is an integer of 6, 8, 10, or 12;

[0064] R 1 each independently is hydrogen, a halogen group, a cyano group, a nitro group, a hydroxyl group, a C 1-20 alkyl group, a C 20 alkyl group, a C 20 alkyl group, a C 20 alkyl group, a C 20 alkyl group, a C 20 alkyl group, a C 1-20 aminoalkyl group, or R 11 to R 14 each independently is hydrogen, a C 1-20 alkyl group, or a C 1-20 hydroxyalkyl group.

[0065] The silsesquioxane can be a mixture of one or more than two selected from the compounds represented by the Chemical Formula 1.

[0066] Specifically, the silicon nitride film etching composition of the present application passivates a silicon oxide film to inhibit corrosion and damage to the silicon oxide film in a silicon nitride film etching process. Furthermore, the silicon nitride film etching composition of the present application is adsorbed after moving to the surface of the silicon oxide film, thereby protecting the surface of the silicon oxide film while effectively inhibiting abnormal growth of the silicon oxide film.

[0067] In addition, the silicon nitride film etching composition of the present application stably maintains a high selectivity ratio to a silicon nitride film by improving phosphoric acid stability even if a high content of phosphoric acid is included, and can provide an advantageous advantage even in a high-temperature etching process.

[0068] The silicon nitride film etching composition of one embodiment of the present application can include a silsesquioxane of Chemical Formula 1 in which n is an integer of 6 or 8 and R1 each independently C 1-20 alkyl, C 1-20 aminoalkyl or the R 11 to R 14 each independently hydrogen or C 1-20 alkyl.

[0069] The silicon nitride film etching composition of one embodiment of the present application can include a silsesquioxane of Chemical Formula 1, in which the R1in the Chemical Formula 1 are each independently C 1-7 alkyl, C 1-7 aminoalkyl or the R 11 to R 14 each independently hydrogen or C 1-7 alkyl.

[0070] The silicon nitride film etching composition of one embodiment of the present application can include a silsesquioxane of Chemical Formula 1, in which at least one of the R1in the Chemical Formula 1 is the remaining R1are each independently C 1-7 alkyl, C 1-7 aminoalkyl or the R 11 to R 14 each independently hydrogen or C 1-7 alkyl.

[0071] As an example, in the Chemical Formula 1, the R 1 is C 1-7 aminoalkyl, the amino group includes an amino group (*-NR'R"), and the R' and R" are each independently hydrogen or C 1-7 alkyl.

[0072] As an example, the C 1-7 alkyl can be represented by *-C 1-7 alkyl-NR'R", and the R' and R" are each independently hydrogen or C 1-7 alkyl.

[0073] As an example, the silsesquioxane of the Chemical Formula 1 can include one or more selected from compounds represented by Chemical Formula 2 and Chemical Formula 3 below:

[0074] [Chemical Formula 2]

[0075]

[0076] [Chemical Formula 3]

[0077]

[0078] In the Chemical Formula 2 and the Chemical Formula 3,

[0079] at least one of R1in R1is each of the remaining R1is independently C 1-7 alkyl, C 1-7 aminoalkyl, or the R 11 to R 14 each independently is hydrogen or C 1-7 alkyl.

[0080] The silicon nitride film etching composition of one embodiment of the present application can include a silsesquioxane of Chemical Formula 1 in which n is an integer of 6 or 8, R1includes at least one and at least one C 1-3 alkyl, or C 1-3 aminoalkyl. At this time, the R 11 to R 14 each independently is hydrogen or C 1-3 alkyl.

[0081] For example, in the Chemical Formula 1, when the R 1 is C 1-3 aminoalkyl, the amino group includes an amino group (*-NR'R"), and R' and R" each independently is hydrogen or C 1-7 alkyl.

[0082] For example, the silsesquioxane of Chemical Formula 1 can have the following structure:

[0083]

[0084]

[0085] The silicon nitride film etching composition of one embodiment of the present application can include a silsesquioxane of Chemical Formula 1 in which n is an integer of 6 or 8, R1includes at least one and at least one C 1-3 aminoalkyl. At this time, the R 11 to R 14 each independently is hydrogen or C 1-3 alkyl. When the structural features described above are satisfied, a significant etching selectivity to a silicon nitride film is exhibited.

[0086] For example, in the Chemical Formula 1, the R 11 to R 14 may each independently be hydrogen, methyl, ethyl, or n-propyl.

[0087] For example, the silsesquioxane can be a liquid at normal temperature.

[0088] As an example, the molecular weight of the silsesquioxane can be in the range of 500 to 8,000.

[0089] In the silicon nitride film etching composition of the present application, the silsesquioxane can be prepared by a hydrolytic polymerization method. However, the polymerization method is not limited thereto, and the hydrolytic polymerization method can be performed by a conventional method.

[0090] As an example, the hydrolytic polymerization method can include a step of reacting tetraammonium hydroxide with trialkoxy(alkyl)silane or trialkoxy(aminoalkyl)silane in an aqueous solution. At this time, the tetraammonium hydroxide and the trialkoxy(alkyl)silane or trialkoxy(aminoalkyl)silane can be added in a molar ratio of 1:0.1 to 1:10, and the step can be performed at a temperature in the range of room temperature to 80°C.

[0091] As an example, the hydrolytic polymerization method can include a step of further adding trialkoxy silane and performing a reaction after reacting tetraalkylammonium hydroxide with tetraalkoxy silane in an aqueous solution. At this time, the tetraalkylammonium hydroxide and the tetraalkoxy silane can be added in a molar ratio of 1:0.1 to 1:10, and based on 1 mole of the tetraalkoxy silane, 0.1 to 20 moles of the trialkoxy silane can be further added, and the step can be performed at a temperature in the range of room temperature to 80°C.

[0092] As an example, the tetraalkylammonium hydroxide can be selected from the group consisting of tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, tetrahexylammonium hydroxide, tetraoctylammonium hydroxide, benzyltriethylammonium hydroxide, diethyldimethylammonium hydroxide, cetyltrimethylammonium hydroxide, and methyltributylammonium hydroxide, and the like.

[0093] As an example, the tetraalkoxy silane can be represented by the following Chemical Formula A.

[0094] [Chemical Formula A]

[0095] Si(OR a )4

[0096] In the Chemical Formula A,

[0097] R a is hydrogen or C 1-3 alkyl.

[0098] As an example, the trialkoxy silane can be represented by the following Chemical Formula B.

[0099] [Chemical Formula B]

[0100] Si(OR a )3(Rb )

[0101] in the formula B,

[0102] R a each independently is hydrogen or C 1-3 alkyl,

[0103] R b is C 1-20 alkyl (space) or C 1-20 aminoalkyl.

[0104] The silicon nitride film etching composition of one embodiment of the present application has a high etching selectivity to a silicon nitride film. In addition, since the high-temperature stability is high, even if used repeatedly, the etching rate reduction rate is low, and thus a stable etching process can be provided, and thus the yield can be greatly improved.

[0105] The etching process using the silicon nitride film etching composition of one embodiment of the present application can be performed at a process temperature of 100 °C or higher, specifically, at a process temperature of 100 to 500 °C, and more specifically, at a process temperature of 150 to 300 °C. As described above, the silicon nitride film etching composition of the present application can maintain the initial composition ratio even in a high-temperature etching process, and since the etching rate and the etching selectivity are less likely to change, and no precipitates are generated, the etching process can be stably performed.

[0106] The silicon nitride film etching composition of one embodiment of the present application can include, relative to the total weight of the silicon nitride film etching composition: 60 to 95 wt% of phosphoric acid; 0.01 to 5.00 wt% of the silsesquioxane; and the balance water.

[0107] The silicon nitride film etching composition of one embodiment of the present application can include: 60 to 90 wt% of phosphoric acid, 0.05 to 3.00 wt% of the silsesquioxane, and the balance water; more specifically, 75 to 90 wt% of phosphoric acid, 0.10 to 2.00 wt% of the silsesquioxane, and the balance water; and most specifically, 80 to 90 wt% of phosphoric acid, 0.10 to 1.50 wt% of the silsesquioxane, and the balance water.

[0108] When the silicon nitride film etching composition satisfying the above range is used in an etching process, an effect of etching a silicon nitride film with high etching selectivity is exhibited, and even after repeated etching processes, excellent etching rate and high etching selectivity to a silicon nitride film can be maintained, and there is no disadvantage in the etching process, and thus it is preferred.

[0109] In addition, the silicon nitride film etching composition of one embodiment of the present application can further include an alcohol solvent. When the alcohol solvent is added, the viscosity of the silicon nitride film etching composition can be adjusted, and thus stable effects can be obtained even at high temperatures in semiconductor manufacturing processes. Furthermore, when the silicon nitride film etching composition is used repeatedly, the etching rate of a silicon nitride film is less likely to vary, and thus the process efficiency is high.

[0110] For example, the alcohol solvent can be one or a mixture of two or more selected from the group consisting of methanol, ethanol, propanol, isopropanol, butanol, isobutanol, tert-butanol, pentanol, hexanol, heptanol, octanol, ethylene glycol, propylene glycol, and tetrahydrofurfuryl alcohol (THFA).

[0111] For example, the alcohol solvent can be included at 0.05 to 10 wt%, specifically at 0.05 to 5 wt%, and more specifically at 0.05 to 3 wt%, relative to the total weight of the silicon nitride film etching composition.

[0112] In addition, the silicon nitride film etching composition of one embodiment of the present application can further include an inorganic acid, a derivative thereof, or a combination thereof.

[0113] For example, the inorganic acid can be one or a mixture of two or more selected from the group consisting of phosphoric acid, polyphosphoric acid, phosphorous acid, and sulfonic acid (e.g., sulfuric acid) or a derivative thereof.

[0114] For example, the polyphosphoric acid can be polyphosphoric acid in which two or more phosphoric acid molecules are condensed, and non-limiting examples thereof can include pyrophosphoric acid, tripolyphosphoric acid, and the like.

[0115] For example, the derivative of the inorganic acid can be selected from the group consisting of trimethyl phosphate, triethyl phosphate, methylphosphonic dimethyl ester, diethyl phosphite, dimethyl phosphate, trimethyl phosphite, diethylamine phosphate, methanesulfonic acid, p-toluenesulfonic acid, benzene sulfonic acid, aminomethyl sulfonic acid, and sulfamic acid, and the like.

[0116] For example, the inorganic acid, the derivative thereof, or the combination thereof can be included at 0.05 to 1 wt%, specifically at 0.1 to 1 wt%, and more specifically at 0.3 to 0.8 wt%, relative to the total weight of the silicon nitride film etching composition.

[0117] In addition, the silicon nitride film etching composition of one embodiment of the present application can further include an ammonium compound. When the ammonium compound is added, the etching rate is less likely to decrease and the selectivity is less likely to vary even when used for a long time, and thus the etching rate can be constantly maintained.

[0118] As an example, the ammonium compound can be any one selected from the group consisting of ammonia, ammonium chloride, ammonium acetate, ammonium phosphate, ammonium persulfate, ammonium sulfate, and ammonium fluoride, or a mixture of two or more thereof, but is not limited thereto.

[0119] As an example, the content of the ammonium compound can be 0.05 to 1% by weight, specifically, 0.1 to 1% by weight, more specifically, 0.3 to 0.8% by weight, with respect to the total weight of the silicon nitride film etching composition.

[0120] The water contained in the silicon nitride film etching composition according to an embodiment of the present application is not particularly limited, but can be deionized water, more specifically, semiconductor process deionized water, which can have a specific resistance value of 18 MΩ·cm or more.

[0121] The silicon nitride film etching composition according to an embodiment of the present application has a high selectivity ratio of a silicon nitride film with respect to a silicon oxide film, and exhibits a significant etching rate with respect to a silicon nitride film.

[0122] The etching selectivity ratio (E SiNx / E SiO2 ) of the silicon nitride film with respect to the silicon oxide film of the silicon nitride film etching composition according to an embodiment of the present application can be 500 or more.

[0123] As an example, the etching selectivity ratio (E SiNx / E SiO2 ) can be 700 or more.

[0124] As an example, the etching selectivity ratio (E SiNx / E SiO2 ) can be 1000 or more.

[0125] As an example, the etching selectivity ratio (E SiNx / E SiO2 ) can be 1000 or more. As an example, the etching selectivity ratio (E SiNx / E SiO2 ) can be 1000 or more.

[0126] As an example, the etching selectivity ratio (E SiNx / E SiO2 ) can be 1000 or more. As an example, the etching selectivity ratio (E SiNx / E SiO2 ) can be 1000 or more.

[0127] As an example, the etching selectivity ratio (E SiNx / E SiO2 ) can be 1000 or more. As an example, the etching selectivity ratio (E SiNx / E SiO2 ) can be 1000 or more.

[0128] In addition, the silicon nitride film etching composition of one embodiment of the present application has an etching rate reduction ratio of a silicon nitride film after repeated etching processes that satisfies the following relation 1.

[0129] [Relation 1]

[0130] ΔERD SiNx ≤ 1 %

[0131] In the relation 1,

[0132] ΔERD SiNx is an etching rate reduction ratio with respect to the initial etching rate of the silicon nitride film.

[0133] The silicon nitride film etching composition can have a stable effect even at high temperatures in semiconductor manufacturing processes because of excellent stability. Furthermore, the etching rate variation with respect to the silicon nitride film is low and process efficiency is high even when the above composition is used repeatedly.

[0134] For example, in the silicon nitride film etching composition, when the content of the silsesquioxane is 0.1 wt%, the etching rate reduction ratio (ΔERD SiNx ) of the silicon nitride film can be 0 to 0.8%, more specifically, 0.01 to 0.5%, and most specifically, 0.01 to 0.1% as the number of batches increases.

[0135] Hereinafter, an etching method using the silicon nitride film etching composition of the present application will be described in detail.

[0136] One embodiment of the present application can be a method for selectively etching a silicon nitride film with respect to a silicon oxide film.

[0137] Another embodiment can be a method for manufacturing a semiconductor device including an etching process for selectively etching a silicon nitride film.

[0138] The silicon nitride film can be a SiN film, a SiON film, a doped SiN film, and the like. As a concept including such a silicon nitride film, specifically, it can refer to a film quality mainly used as an insulating film when a gate electrode or the like is formed. However, as long as it is a technical field aimed at selectively etching a silicon nitride film with respect to a silicon oxide film, it can be used without limitation.

[0139] Furthermore, there are no limitations on the silicon oxide film as long as it is a silicon oxide film commonly used in the art. For example, it can be selected from spin-on-dielectric (SOD) films, high-density plasma (HDP) films, thermally oxidized films, borophosphate silicon glass (BPSG) films, phospho silicon glass (PSG) films, boro silicon glass (BSG) films, polysilazane (PSZ) films, fluorinated silicon glass (FSG) films, low-pressure tetraethyl orthosilicate (LP-TEOS) films, plasma-enhanced tetraethyl orthosilicate (PETEOS) films, high-temperature oxide (HTO) films, medium-temperature oxide (MTO) films, and undoped silicon glass. At least one film is selected from the group consisting of USG (Ultra-Ultra-Glass) films, spin-on-glass (SOG) films, advanced planarization layer (APL) films, atomic layer deposition (ALD) films, plasma-enhanced oxide (PDE) films, and O3-tetraethyl orthosilicate (O3-TEO) films. However, this is only a specific example and is not a limitation.

[0140] Regarding the etching method of the silicon nitride film etching composition according to an embodiment of the present invention and the manufacturing method of the semiconductor device comprising the same, when the aforementioned silicon nitride film and silicon oxide film are mixed, the silicon nitride film can be selectively etched relative to the silicon oxide film, and the etching speed is fast. No precipitates are generated after etching, so defects can be minimized when manufacturing semiconductor devices.

[0141] In addition, the silicon nitride film etching composition of the present application has high temperature stability, thereby effectively suppressing the problem of etching a silicon oxide film at a high temperature. Thus, no precipitates are generated by etching the silicon oxide film, and substrate defects can be prevented, and excellent semiconductor device characteristics can be exhibited by selectively etching the silicon nitride film.

[0142] The method for selectively etching a silicon nitride film using the above-described silicon nitride film etching composition can be performed according to the processing method generally used in the art. As a non-limiting example, a method in which a substrate is immersed in an etching composition solution or a spray method, etc. can be used.

[0143] As an example, the method can be performed at a process temperature of 100°C or higher, specifically, at a process temperature of 100 to 500°C, more specifically, at a process temperature of 100 to 300°C.

[0144] In the case of the method, in the case where a silicon oxide film, a silicon nitride film, and a photoresist film, etc. are mixed and formed on a substrate, only the silicon nitride film is selectively and rapidly etched with respect to the silicon oxide film, which is advantageous in suppressing the generation of precipitates. Thus, according to the present application, the height of an effective oxide film can be effectively adjusted.

[0145] The substrate can use a variety of substances, for example, silicon, quartz, glass, a silicon wafer, a polymer, a metal, and a metal oxide, etc. can be used, but is not limited thereto. As an example of the polymer substrate, a film substrate such as polyethylene terephthalate, polycarbonate, polyimide, polyethylene naphthalate, a cycloolefin polymer, etc. can be used, but is not limited thereto.

[0146] The silicon oxide film, the silicon nitride film, and the photoresist film can each be formed as a single film, a double film, or a multiple film (a multilayer film), and in the case of a double film or a multiple film, the order of stacking is not limited.

[0147] The method for manufacturing a semiconductor device including an etching process for selectively etching a silicon nitride film using the above-described silicon nitride film etching composition can also be performed according to the method generally used in the art.

[0148] According to the semiconductor device manufacturing method, in a semiconductor device in which silicon nitride films and silicon oxide films are alternately stacked or mixed, selective etching of the silicon nitride film can be achieved, effectively suppressing damage to the silicon oxide film, thereby minimizing the damage to the silicon oxide film caused by etching, and greatly improving the stability, efficiency, and reliability of the semiconductor device manufacturing process. In this invention, the type of semiconductor device is not particularly limited.

[0149] Therefore, the etching method of the present invention can selectively remove the silicon nitride film stacked on the silicon oxide film. Even with increased processing time, it can maintain a constant etching rate and etching selectivity, thus enabling its effective application in processes requiring selective etching of the silicon nitride film. In particular, the etching method of the present invention exhibits excellent performance in suppressing precipitate formation and effectively protecting the silicon oxide film, thereby ensuring the stability and reliability of the process.

[0150] The present invention will now be described in more detail based on embodiments and comparative examples. However, the embodiments and comparative examples described below are merely examples for further detailed explanation of the present invention, and the present invention is not limited to the embodiments and comparative examples described below. In the present invention, unless otherwise specified, the temperature unit refers to °C, and unless otherwise specified, the amount of composition used refers to % by weight.

[0151] (Evaluation Method)

[0152] 1) Etching rate measurement

[0153] Specifically, silicon nitride (SiN) films and silicon oxide films are prepared by chemical vapor deposition, similar to semiconductor manufacturing processes. As the aforementioned silicon nitride film, LP nitride (thickness...) is used. The aforementioned silicon oxide film used a PE-TEOS film (thickness...). )membrane.

[0154] The thickness of the composition before etching was measured using an ellipsometer (available from JA WOOLLAM, M-2000U) as a thin film thickness measuring device. The wafers were immersed in the compositions of the following examples and comparative examples, maintained at an etching temperature of 160–230°C, for 30 minutes in a quartz bath to perform the etching process. After etching, the wafers were washed with ultrapure water, and then dried completely using a drying device, and the etching rate was measured.

[0155] Regarding the etching rate, the difference between the thickness before and after etching is divided by the etching time (minutes) using an ellipsometry. The etching selectivity calculated in this way is shown in Table 2 below.

[0156] 2) Etching rate reduction ratio measurement

[0157] The etching rate of the nitride film of the composition is measured by the etching rate measurement method.

[0158] The etching rate reduction ratio (ΔERD SiNx ) is measured by repeating the etching process 10 times without replacing the composition that does not have a silicon nitride film, using one batch of the etching process. The etching rate reduction ratio (ΔERD SiNx (%) is calculated from the following Equation 1. At this time, the initial etching rate is the etching rate at the time of the first etching process.

[0159] [Equation 1]

[0160] ΔERD SiNx = [1 - {(etching rate at the time of the n-th repeated etching process) / (initial etching rate)}] x 100

[0161] The results are shown in Table 3 below.

[0162] 3) Measurement of occurrence of precipitates

[0163] The surface of the silicon oxide film etched using the compositions of the following examples and comparative examples is measured by an electron scanning microscope (SEM) to confirm the occurrence of precipitates (O: occurrence / X: non-occurrence).

[0164] The results are shown in Table 3 below.

[0165] 4) Level of occurrence of abnormal growth of oxide film Measurement

[0166] The difference between the thickness of the oxide film before etching and the thickness of the oxide film after etching using the compositions of the following examples and comparative examples is measured using an ellipsometer (M-2000U available from J. A WOOLLAM Co.) as a thin film thickness measurement device. At this time, the difference in thickness before and after etching is evaluated as the abnormal growth thickness.

[0167] The results are shown in Table 3 below.

[0168] 5) Structure confirmation

[0169] The structure and composition of the products of the following preparation examples are confirmed by 1 H-NMR, 13 C-NMR and 29Si-NMR analysis was performed for confirmation. In addition, the three-dimensional structure of the product was predicted by empirical potential structure refinement (EPSR) modelling. In addition, elemental analysis of the product was performed by XPS spectrum (refer to Chem. Eur. J. 2014, 20, 15966-15974; Dalton Trans., 2008, 36-39; Phys. Chem. Chem. Phys., 2019, 21, 6732-6742).

[0170] (Preparation Example 1)

[0171] Into a 500 mL 3-necked flask equipped with a cooling tube and a stirrer, 100 g of water was added, 200 g of tetraethyl orthosilicate and 437.5 g of 20% aqueous tetramethylammonium hydroxide solution (mole of tetraethyl orthosilicate / mole of tetramethylammonium hydroxide = 1) were added, and stirring was performed at 70°C for 3 hours. Then, (N,N-diethyl-3-aminopropyl)triethoxysilane was added so that the molar ratio thereof to tetraethyl orthosilicate was 1:1, and after stirring at 30°C for 12 hours, the product was recovered by removing low-boiling substances at 60°C using a vacuum pump.

[0172]

[0173] In the structure, R 1 is *-O-N + (CH3)4, *-OH, or *-(CH2)3N(CH2CH3)2, at a molar ratio of 1:1:2.

[0174] (Preparation Example 2)

[0175] Into a 500 mL 3-necked flask equipped with a cooling tube and a stirrer, 100 g of water was added, 200 g of tetraethyl orthosilicate and 707 g of 20% aqueous tetraethylammonium hydroxide solution (mole of tetraethyl orthosilicate / mole of tetraethylammonium hydroxide = 1) were added, and stirring was performed at 70°C for 3 hours. Then, (N,N-diethyl-3-aminopropyl)triethoxysilane was added so that the molar ratio thereof to tetraethyl orthosilicate was 1:2, and after stirring at 30°C for 12 hours, the product was recovered by removing low-boiling substances at 60°C using a vacuum pump.

[0176] In the structure shown in Preparation Example 1, the R 1 is *-O-N + (CH3)4, *-OH, or *-(CH2)3N(CH2CH3)2, at a molar ratio of 1:1:4.

[0177] (Preparation Example 3)

[0178] Into a 500 mL 3-necked flask equipped with a cooling tube and a stirrer, 100 g of water was added, and 157.7 g of trimethoxy (propyl) silane and 437.5 g of 20% aqueous tetramethylammonium hydroxide solution (mole of trimethoxy (propyl) silane / mole of tetramethylammonium hydroxide = 1) were added. After stirring at 30°C for 12 hours, the product was recovered by removing low-boiling substances at 60°C using a vacuum pump.

[0179] In the structure shown in the Preparation Example 1, the R 1 is *-O-N + (CH3)4, *-OH, or *-(CH2)3N(CH2CH3)2, at a molar ratio of 1:1:4.

[0180] (Preparation Example 4)

[0181] Into a 500 mL 3-necked flask equipped with a cooling tube and a stirrer, 100 g of water was added, and 200 g of tetraethyl orthosilicate and 976 g of 20% aqueous tetrapropylammonium hydroxide solution (mole of tetraethyl orthosilicate / mole of tetrapropylammonium hydroxide = 1) were added. After stirring at 70°C for 3 hours, (N,N-diethyl-3-aminopropyl) triethoxysilane was added such that the molar ratio thereof to tetraethyl orthosilicate was 1:2. After stirring at 30°C for 12 hours, the product was recovered by removing low-boiling substances at 60°C using a vacuum pump.

[0182] In the structure shown in the Preparation Example 1, the R 1 is *-O-N + (CH3)4, *-OH, or *-(CH2)3N(CH2CH3)2, at a molar ratio of 1:1:4.

[0183] (Examples 1 to 6 and Comparative Examples 1 to 4)

[0184] After mixing the composition ratios shown in Table 1 below, the mixture was stirred at room temperature at a speed of 500 rpm for 5 minutes to prepare a silicon nitride film etching composition. The amount of water was set to the balance so that the total weight of the composition was 100 wt%, thereby preparing 300 g of a silicon nitride film etching composition.

[0185] [Table 1]

[0186]

[0187]

[0188] [Table 2]

[0189]

[0190] [Table 3]

[0191]

[0192]

[0193] As shown in the above Tables 2 and 3, the initial etching selectivity of the etching process was 700 or more for each of the silicon nitride etching compositions of the present application. In particular, for the silicon nitride film etching composition containing the silsesquioxane having an aminopropyl group (functional group), the initial etching selectivity of the etching process was confirmed to be 1070 to 1515, which can achieve a very high etching selectivity.

[0194] In addition, it was confirmed that even if the etching process was repeatedly performed to repeatedly use the silicon nitride film etching composition several times, the etching rate reduction rate of the silicon nitride film was very low. In particular, for all of the silicon nitride etching compositions of the present application, no precipitates were generated even if the etching process was repeatedly performed, and no abnormal growth of the silicon oxide film occurred.

[0195] On the other hand, the initial etching selectivity of the silicon nitride film etching compositions of Comparative Example 1, Comparative Example 3, and Comparative Example 4 in the etching process was less than 35, which was significantly lower than the examples of the present application. In addition, when the etching process was repeatedly performed, precipitates were generated in all of the comparative examples, and abnormal growth of the silicon oxide film occurred. In addition, in the silicon nitride film etching compositions of all of the comparative examples, the etching rate reduction rate of the silicon nitride film by the repeated etching process was significantly high, being 3% or more.

[0196] In summary, according to the present application, the silicon nitride film can be selectively etched with an excellent etching selectivity, and even if used several times, the etching rate reduction rate is low, and by maintaining the initial etchability, the production efficiency can be significantly improved. In addition, the damage to the film quality of the silicon oxide film in the etching process can be minimized, and the formation of precipitates can be effectively suppressed, thereby providing a high-quality semiconductor device.

[0197] The silicon nitride film etching composition of the present application can selectively etch the silicon nitride film with a high selectivity compared to the silicon oxide film, and by suppressing the etching rate of the silicon oxide film, the Effective Field Oxide Height (EFK) can be effectively adjusted.

[0198] In addition, in the silicon nitride film etching composition of the present application, even if the etching treatment time is increased or repeatedly used, the effect of less change in the etching rate of the silicon nitride film and the etching selectivity is maintained, and ultimately the productivity in the manufacturing process of the semiconductor for selectively etching the silicon nitride film can be improved. In addition, no precipitates are generated when high-temperature etching is performed, and at the same time, no abnormal growth in which the thickness of the silicon oxide film is increased is generated.

[0199] In addition, the silicon nitride film etching composition of the present application is excellent in storage stability, and can maintain a constant etching rate and etching selectivity ratio for a silicon nitride film even if used or stored for a long period of time.

[0200] In addition, the silicon nitride film etching composition of the present application has an excellent effect of suppressing the generation of precipitates when used in an etching process and semiconductor manufacturing engineering.

[0201] The present application is not limited to the above-described embodiments, and various substitutions, modifications and changes can be made without departing from the scope of the technical idea of the present application, which will be apparent to those skilled in the art to which the present application pertains.

Claims

1.A silicon nitride film etching composition, wherein, comprising, relative to the total weight of the silicon nitride film etching composition: 60 to 95% by weight of phosphoric acid; 0.01 to 5.00% by weight of a silsesquioxane represented by the following Chemical Formula 1; and a balance of water; [Chemical Formula 1] (R 1 SiO3 / 2) n in the Chemical Formula 1, n is an integer of 6, 8, 10, or 12; R 1 each independently is hydroxy, C 1-20 alkyl, C1-C 20 alkoxy, C 1-20 aminoalkyl or R 11 to R 14 each independently is hydrogen or C 1-20 alkyl. 2.The silicon nitride film etching composition according to claim 1, wherein, in the Chemical Formula 1, the n is an integer of 6 or 8, R 1 each independently C 1-20 alkyl, C 1-20 aminoalkyl or R 11 to R 14 each independently hydrogen or C 1-20 alkyl. 3.The silicon nitride film etching composition according to claim 1, wherein, in the Chemical Formula 1, R 1 each independently C 1-7 alkyl, C 1-7 aminoalkyl or R 11 to R 14 each independently hydrogen or C 1-7 alkyl. 4.The silicon nitride film etching composition according to claim 1, wherein, in the Chemical Formula 1, at least one R 1 in the group 1 is the remaining R 1 are each independently C 1-7 alkyl, C 1-7 aminoalkyl or the R 11 groups R 14 are each independently hydrogen or C 1-7 alkyl. 5.The silicon nitride film etching composition according to claim 1, wherein, further comprising an alcoholic solvent, which is one or a mixture of two or more selected from the group consisting of methanol, ethanol, propanol, isopropanol, butanol, isobutanol, tert-butanol, pentanol, hexanol, heptanol, octanol, ethylene glycol, propylene glycol, and tetrahydrofurfuryl alcohol. 6.The silicon nitride film etching composition according to claim 1, wherein, further comprising an inorganic acid, a derivative thereof, or a combination thereof, the derivative of the inorganic acid is selected from trimethyl phosphate, triethyl phosphate, dimethyl methylphosphonate, diethyl phosphite, dimethyl phosphate, trimethyl phosphite, diethylamine phosphate, methanesulfonic acid, p-toluenesulfonic acid, benzene sulfonic acid, aminomethyl sulfonic acid, and sulfamic acid. 7.The silicon nitride film etching composition according to claim 1, wherein, further comprising an ammonium compound, which is any one or a mixture of two or more selected from the group consisting of aqueous ammonia, ammonium chloride, ammonium acetate, ammonium phosphate, ammonium persulfate, ammonium sulfate, and ammonium fluoride. 8.The silicon nitride film etching composition according to claim 1, wherein, The etching selectivity ratio E of the silicon nitride film to the silicon oxide film of the silicon nitride film etching composition SiNx / E SiO2 is 500 or more. 9.The silicon nitride film etching composition according to claim 8, wherein, The etching rate of the silicon nitride film to the silicon nitride film of the silicon nitride film etching composition is 20 to 1000 A / min The etching rate of the silicon nitride film to the silicon nitride film of the silicon nitride film etching composition is 20 to 1000 A / min 10.The silicon nitride film etching composition according to claim 9, wherein, the etching rate reduction rate of the silicon nitride film after the repeated etching process satisfies the following Relationship Formula 1: [Relationship Formula 1] △ERD SiNx ≤ 1% in the Relationship Formula 1, △ERD SiNx The etching rate reduction ratio is the ratio of the etching rate of the silicon nitride film after the treatment to the initial etching rate of the silicon nitride film. 11.A method of selectively etching a silicon nitride film compared to a silicon oxide film, wherein, the method utilizes the silicon nitride film etching composition according to claim 1. 12.A method of manufacturing a semiconductor device, wherein, the method includes an etching process utilizing the silicon nitride film etching composition according to claim 1.

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