Silicon precursor compound, method for preparing the same, and method for preparing a silicon-containing thin film.
A novel silicon precursor compound, prepared through specific chemical reactions, addresses the challenge of achieving high-quality silicon-containing thin films with uniform thickness on irregular surfaces, enabling efficient deposition in both ALD and CVD processes.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- MERCK PATENT GMBH
- Filing Date
- 2024-07-19
- Publication Date
- 2026-07-21
AI Technical Summary
Existing methods for preparing silicon-containing thin films, such as silicon oxide, silicon nitride, and silicon oxynitride films, do not provide high-quality films with uniform thickness on surfaces with large irregularities, and there is a need for improved silicon precursor compounds that can be effectively used in atomic layer deposition (ALD) and chemical vapor deposition (CVD).
A novel silicon precursor compound represented by specific chemical formulas, prepared through a multi-step process involving chlorosilane derivatives, hydrocarbylhydrazine compounds, and alkyl-lithium reactions, which can form silicon-containing thin films with excellent quality and volatility for both ALD and CVD processes.
The silicon precursor compound enables the deposition of high-quality silicon-containing thin films at fast rates, even at high temperatures, and is suitable for both ALD and CVD, ensuring uniform thickness and purity.
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Abstract
Description
[Technical Field]
[0001] The present invention relates to silicon precursor compounds, methods for preparing them, and methods for preparing silicon-containing thin films using silicon precursor compounds. [Background technology]
[0002] Silicon-containing thin films, such as silicon oxide films, silicon nitride films, silicon oxynitride films, and silicon carbonitride films, are among the essential thin films for driving microelectronic devices, including non-semiconductor (logic) and semiconductor devices.
[0003] Atomic layer deposition (ALD) or chemical vapor deposition (CVD) are widely used to prepare silicon-containing thin films. Of these, atomic layer deposition (ALD) is a method that sequentially supplies the silicon compound gas and reaction gas necessary for film formation. This method has the advantage of being able to form silicon-containing thin films of uniform thickness even on surfaces with large irregularities. For this reason, atomic layer deposition (ALD) is widely used.
[0004] Chemical vapor deposition (CVD) and atomic layer deposition (ALD) differ from each other in terms of their mechanisms of action. Various silicon precursors are used to prepare silicon-containing thin films according to various process conditions, depending on their physical and chemical properties. [Prior art documents] [Patent Documents]
[0005] [Patent Document 1] Korean Published Patent No. 2011-0017404 [Overview of the Initiative] [Problems that the invention aims to solve]
[0006] The object of the present invention is to provide a novel silicon precursor compound that is advantageous for preparing silicon-containing thin films of excellent quality, and a method for preparing the same.
[0007] In addition, another objective is to provide a silicon-containing thin film using the silicon precursor compound, and a method for preparing it. [Means for solving the problem]
[0008] To achieve the above objectives of the present invention, a silicon precursor compound is provided, characterized by being represented by the following formula 1. [Formula 1] [ka]
[0009] In Formula 1, each R1 is independently a linear or branched saturated or unsaturated hydrocarbon group having 1 to 4 carbon atoms, or an isomer thereof; each R2 to R5 is independently hydrogen (H), a halogen, or a linear or branched saturated or unsaturated hydrocarbon group having 1 to 4 carbon atoms; each A and A' is independently NR6R7 or R8, provided that at least one of A and A' is NR6R7; each R6 and R7 is independently a methyl group or an ethyl group; and R8 is hydrogen (H), a halogen, or a linear or branched saturated or unsaturated hydrocarbon group having 1 to 4 carbon atoms.
[0010] In one embodiment, the silicon precursor compound may have an asymmetric structure represented by the following formula 2. [Formula 2] [ka]
[0011] In Formula 2, each R1 is independently a linear or branched saturated or unsaturated hydrocarbon group having 1 to 4 carbon atoms, or an isomer thereof; each of R2 to R5 is independently hydrogen (H), halogen, or a linear or branched saturated or unsaturated hydrocarbon group having 1 to 4 carbon atoms; each of R6 and R7 is independently a methyl group or an ethyl group; and R8 is hydrogen (H), halogen, or a linear or branched saturated or unsaturated hydrocarbon group having 1 to 4 carbon atoms.
[0012] In another embodiment, the silicon precursor compound may have a symmetric structure represented by the following Formula 3. [Formula 3] [Chemical Formula]
[0013] In Formula 3, each R1 is independently a linear or branched saturated or unsaturated hydrocarbon group having 1 to 4 carbon atoms, or an isomer thereof; each of R2 and R4 is independently hydrogen (H), halogen, or a linear or branched saturated or unsaturated hydrocarbon group having 1 to 4 carbon atoms; and each of R6 and R7 is independently a methyl group or an ethyl group.
[0014] The silicon precursor compound of the present invention is preferably at least one selected from the following Compounds (1) to Compound (25). [Chemical Formula] [Chemical Formula]
[0015] To achieve another object of the present invention, a method for preparing a silicon precursor compound is provided. The method includes a first step of reacting a chlorosilane derivative with any one compound selected from N,N-dimethylhydrazine, N,N-diethylhydrazine, and 1-ethyl-1-methylhydrazine as a hydrocarbylhydrazine compound to form a first compound, a second step of reacting the first compound with an alkyl-lithium (alkyl-Li) to form a second compound containing lithium, and a third step of reacting the second compound with a silane compound to prepare a silicon precursor compound represented by Formula 2.
[0016] The first compound formed in the first step is preferably a compound represented by the following Formula 9. [Formula 9] [Chemical Formula]
[0017] In Formula 9, each R1 is independently a linear or branched saturated or unsaturated hydrocarbon group having 1 to 4 carbon atoms or an isomer thereof, and each of R3, R5, and R8 is independently hydrogen (H), a halogen, or a linear or branched saturated or unsaturated hydrocarbon group having 1 to 4 carbon atoms.
[0018] In the method for preparing the silicon precursor compound of the present invention, when at least one of R2 and R4 in the silicon precursor compound represented by Formula 2 is a halogen, the method may further include a fourth step of reacting the silicon precursor compound with a metal hydride as a reducing agent.
[0019] In the method for preparing the silicon precursor compound of the present invention, the silane compound is produced by reacting a chlorosilane derivative with a secondary amine.
[0020] A method for preparing a silicon precursor compound of the present invention may include a first step of reacting a hydrocarbylhydrazine compound with alkyl-lithium (alkyl-Li) to form a third compound containing lithium, and a second step of reacting the third compound with a silane compound to prepare a silicon precursor compound represented by formula 3.
[0021] The third compound is preferably a compound represented by the following formula 11. [Formula 11] [ka]
[0022] In formula 11, R1 is independently a linear or branched saturated or unsaturated hydrocarbon group having 1 to 4 carbon atoms, or an isomer thereof.
[0023] When at least one of R2 and R4 in the silicon precursor compound represented by formula 3 is a halogen, the method may further include a third step of reacting the silicon precursor compound with a metal hydride as a reducing agent.
[0024] To achieve another objective of the present invention, a method for preparing a silicon-containing thin film is provided, which may include forming a silicon-containing thin film using a silicon precursor compound represented by Formula 1.
[0025] In the method for preparing a silicon-containing thin film of the present invention, the silicon precursor compound is preferably selected from the group consisting of compound (1) to compound (25).
[0026] In a method for preparing a silicon-containing thin film according to the present invention, the silicon-containing thin film can be deposited by chemical vapor deposition (CVD) or atomic layer deposition (ALD).
[0027] The silicon-containing thin film may be any one selected from the group consisting of silicon oxide film (SiO2), silicon oxycarbide film (SiOC), silicon nitride film (SiN), silicon oxynitride film (SiON), silicon carbonitride film (SiCN), and silicon carbide film (SiC).
[0028] According to a particular embodiment of the method for preparing a silicon-containing thin film of the present invention, a silicon oxide film (SiO2) can be formed by atomic layer deposition. The atomic layer deposition according to the particular embodiment includes providing a substrate in a reactor, introducing a silicon precursor compound according to the present invention into the reactor, purging the reactor with a purge gas, introducing an oxygen-containing source into the reactor and reacting it with the silicon precursor compound according to the present invention to form a silicon oxide film, and purging the reactor with a purge gas.
[0029] In certain embodiments, the purge gas is used to remove unconsumed reactants and reaction by-products. Preferably, the purge gas is selected from the group consisting of nitrogen, helium, argon, and mixtures thereof, but is not limited to these.
[0030] The oxygen-containing source according to a particular embodiment is preferably selected from the group consisting of oxygen, peroxides, oxygen plasma, water vapor, water vapor plasma, hydrogen peroxide, ozone sources, and mixtures thereof, but is not limited thereto. Preferably, the oxygen-containing source may include plasma, and the plasma may be generated in situ.
[0031] In addition, atomic layer deposition according to a particular embodiment may be carried out at one or more temperatures below approximately 500°C. In this case, a person skilled in the art can appropriately select the lower limit of the temperature depending on the type of oxygen source used. Preferably, the silicon oxide film may be formed at one or more temperatures between approximately 300°C and 450°C.
[0032] According to another specific embodiment of the method for preparing silicon-containing thin films of the present invention, a silicon nitride (SiN) film can be formed by plasma-enhanced atomic layer deposition. Plasma-enhanced atomic layer deposition according to a specific embodiment may include providing a substrate in a reactor, introducing a silicon precursor compound according to the present invention into the reactor, purging the reactor with a purge gas, introducing a nitrogen-containing plasma source and an inert gas into the reactor to react with the silicon precursor compound according to the present invention to form a silicon nitride film, and purging the reactor with a purge gas.
[0033] In certain embodiments, the purge gas is used to remove unconsumed reactants and reaction by-products. Preferably, the purge gas is selected from the group consisting of nitrogen, helium, argon, and mixtures thereof, but is not limited to these.
[0034] A nitrogen-containing plasma source according to a particular embodiment is preferably selected from the group consisting of nitrogen plasma, nitrogen and argon mixed plasma (nitrogen and argon plasma), ammonia plasma, nitrogen and ammonia mixed plasma (nitrogen and ammonia plasma), ammonia and helium mixed plasma (ammonia and helium plasma), ammonia and argon mixed plasma (ammonia and argon plasma), ammonia and nitrogen mixed plasma (ammonia and nitrogen plasma), NF3 plasma, organic amine plasma, and mixtures thereof, but is not limited to these.
[0035] In addition, plasma-enhanced atomic layer deposition according to a particular embodiment may be carried out at one or more temperatures below about 400°C. In this case, those skilled in the art can appropriately select the lower limit of the temperature depending on the type of nitrogen-containing plasma source used. Preferably, the silicon nitride film may be formed at one or more temperatures between about 250°C and 400°C, more preferably at about 350°C. [Effects of the Invention]
[0036] The silicon precursor compound of the present invention exhibits sufficient volatility to be applicable to both atomic layer deposition (ALD) and chemical vapor deposition (CVD) for preparing silicon-containing thin films. In particular, because it enables deposition at a fast rate even at high temperatures, it is possible to prepare silicon-containing thin films of excellent quality.
[0037] However, the effects of the present invention are not limited to those mentioned above. [Brief explanation of the drawing]
[0038] [Figure 1] The hydrogen nuclear magnetic resonance (1H-NMR) spectra of silicon precursor compounds prepared according to Example 1 of the present invention are shown. [Figure 2] The hydrogen nuclear magnetic resonance (1H-NMR) spectra of silicon precursor compounds prepared according to Example 2 of the present invention are shown. [Figure 3] The hydrogen nuclear magnetic resonance (1H-NMR) spectra of silicon precursor compounds prepared according to Example 3 of the present invention are shown. [Figure 4] This graph shows the results of thermogravimetric analysis (TGA) of silicon precursor compounds prepared according to the examples of the present invention. [Figure 5] This graph shows the results of measuring the vapor pressure of silicon precursor compounds prepared according to Examples 1, 2, and 3 of the present invention. [Figure 6] This graph shows the sequence of each pulse in the silicon nitride film deposition process. [Figure 7] This graph shows the deposition rate of silicon nitride film as a function of substrate temperature. [Figure 8] This graph shows the sequence of pulses in the silicon oxide thin film deposition process. [Figure 9] This graph shows the deposition rate of silicon oxide thin films as a function of substrate temperature. [Figure 10]This is an image of a silicon oxide thin film deposited according to the present invention, observed using a transmission electron microscope (TEM). [Figure 11] This is the result of analyzing the composition of a silicon oxide thin film deposited according to the present invention using AES (Auger Electron Spectroscopy). [Modes for carrying out the invention]
[0039] The following describes in detail silicon precursor compounds, methods for preparing them, silicon-containing thin films using silicon precursor compounds, and methods for preparing them.
[0040] The silicon precursor compound of the present invention can be represented by the following formula 1. [Formula 1] [ka]
[0041] In Formula 1, each R1 is independently a linear or branched saturated or unsaturated hydrocarbon group having 1 to 4 carbon atoms, or an isomer thereof; each R2 to R5 is independently hydrogen (H), a halogen, or a linear or branched saturated or unsaturated hydrocarbon group having 1 to 4 carbon atoms; each A and A' is independently NR6R7 or R8, provided that at least one of A and A' is NR6R7; each R6 and R7 is independently a methyl group or an ethyl group; and R8 is hydrogen (H), a halogen, or a linear or branched saturated or unsaturated hydrocarbon group having 1 to 4 carbon atoms.
[0042] NR6R7 in A and A' is an amine group. Preferably, NR6R7 in A and A' may be any one selected from dimethylamine, ethylmethylamine, and diethylamine.
[0043] The silicon precursor compound of the present invention may have an asymmetric or symmetric structure.
[0044] When the silicon precursor compound has an asymmetric structure, the silicon precursor compound can be represented by the following formula 2. [Formula 2] [ka]
[0045] In Formula 2, R1 is independently a linear or branched saturated or unsaturated hydrocarbon group having 1 to 4 carbon atoms, or an isomer thereof; R2 to R5 are independently hydrogen (H), a halogen, or a linear or branched saturated or unsaturated hydrocarbon group having 1 to 4 carbon atoms; R6 and R7 are independently a methyl group or an ethyl group; and R8 is hydrogen (H), a halogen, or a linear or branched saturated or unsaturated hydrocarbon group having 1 to 4 carbon atoms.
[0046] When the silicon precursor compound has a symmetrical structure, the silicon precursor compound can be represented by the following formula 3. [Formula 3] [ka]
[0047] In formula 3, R1 is independently a linear or branched saturated or unsaturated hydrocarbon group having 1 to 4 carbon atoms, or an isomer thereof; R2 and R4 are independently hydrogen (H), a halogen, or a linear or branched saturated or unsaturated hydrocarbon group having 1 to 4 carbon atoms; and R6 and R7 are independently a methyl group or an ethyl group.
[0048] Each hydrocarbon group in formulas 1 to 3 can independently be any one selected from the group consisting of a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an ethenyl group, and their isomers. Preferably, any one selected from the group consisting of a methyl group, an ethyl group, and an ethenyl group can be used.
[0049] The halogen may be one selected from the group consisting of chlorine (Cl), bromine (Br), iodine (I), and fluorine (F). Among these, chlorine (Cl) is preferably used.
[0050] When the silicon precursor compound of the present invention has an asymmetric structure, the silicon precursor compound can be prepared by the method shown in reaction scheme 1 or reaction scheme 2 below. [Reaction Scheme 1] [ka] [Reaction Scheme 2] [ka]
[0051] In reaction schemes 1 and 2, R1 to R8 are as defined above, and MH is a metal hydride.
[0052] In this specification, the terms first compound, second compound, and third compound are used solely for the purpose of distinguishing the compounds formed in each step of the method for preparing silicon precursor compounds.
[0053] The method for preparing a silicon precursor compound according to reaction scheme 1 is carried out sequentially by: a first step of reacting a chlorosilane derivative represented by formula 7 with a hydrocarbylhydrazine compound represented by formula 8 to form a first compound represented by formula 9; a second step of reacting the first compound with alkyl-lithium (alkyl-Li) to form a second compound represented by formula 10; and a third step of reacting the second compound with a silane compound represented by formula 6 to prepare a silicon precursor compound represented by formula 2.
[0054] In a method for preparing a silicon precursor compound, in the first step, triorganochlorosilane as a chlorosilane derivative is reacted with a hydrocarbylhydrazine compound represented by formula 8 in a nonpolar solvent at a low temperature of about -20°C to replace Cl with an amine, and then filtered and distilled under reduced pressure to form the compound of formula 9.
[0055] In the second step, the compound of formula 9 formed in the first step is reacted with alkyl-lithium (alkyl-Li) in a nonpolar solvent at a low temperature of approximately -20°C to lithify and form the compound of formula 10.
[0056] Alkyl-Li refers to lithium containing an alkyl group having 1 to 10 carbon atoms. Examples include methyllithium, ethyllithium, propyllithium, butyllithium, and isobutyllithium.
[0057] In the third step, a silicon precursor compound is formed by reacting it with a silane compound represented by formula 6. Then, the reaction product, the salt (LiCl), and unreacted substances are removed by filtration, and distillation is performed under reduced pressure to obtain a silicon precursor compound having an asymmetric structure represented by formula 2.
[0058] Another method for preparing the silicon precursor compound shown in reaction scheme 2 is carried out in the same manner as reaction scheme 1 above, wherein in reaction scheme 2, a fourth step is performed in which the silicon precursor compound is reacted with a metal hydride (MH) as a reducing agent, when at least one of R2 and R4 in the silicon precursor compound represented by formula 2' of reaction scheme 2 is a halogen selected from fluorine (F), chlorine (Cl), bromine (Br), or iodine (I).
[0059] The metal hydride (MH) may be at least one selected from the group consisting of lithium hydride (LiH), sodium hydride (NaH), lithium borohydride (LiBH4), lithium aluminum hydride (LiAlH4), sodium aluminum hydride (NaAlH4), and lithium sodium borohydride (NaBH4). As an example, lithium hydride (LiH) may be used as the metal hydride (MH) together with tetrahydrofuran (THF) to carry out a reduction reaction.
[0060] Preferably, when at least one of R2 and R4 in formula 2' is chlorine (Cl), the fourth step is carried out.
[0061] In the method for preparing silicon precursor compounds according to reaction schemes 1 and 2, the silane compound of formula 6 can be prepared as shown in reaction scheme 3 below. Specifically, a chlorosilane derivative represented by formula 4 is reacted with a secondary amine represented by formula 5 in a nonpolar solvent at a low temperature of about -20°C to replace Cl with the amine, and then filtered and distilled under reduced pressure to form the compound of formula 6. [Reaction Scheme 3] [ka]
[0062] In reaction scheme 3, R2, R4, R6, and R7 are as defined above.
[0063] The silicon precursor compound having an asymmetric structure is at least one selected from the following compounds (1) to (15). [ka]
[0064] When the silicon precursor compound of the present invention has a symmetrical structure, the silicon precursor compound can be prepared by the method shown in reaction scheme 4 or reaction scheme 5 below. [Reaction Scheme 4] [ka] [Reaction Scheme 5] [ka]
[0065] In reaction schemes 4 and 5, R1 to R7 are as defined above, and MH is a metal hydride.
[0066] The method for preparing the silicon precursor compound according to reaction scheme 4 is carried out sequentially, consisting of a first step of reacting the hydrocarbylhydrazine compound of formula 8 with alkyl-lithium (alkyl-Li) to form a third compound represented by formula 11, and a second step of reacting the third compound with the silane compound represented by formula 6 to prepare the silicon precursor compound represented by formula 3.
[0067] In a method for preparing silicon precursor compounds, in the first step, the hydrocarbylhydrazine compound of formula 8 is reacted with alkyl-lithium (alkyl-Li) in a nonpolar solvent at a low temperature of about -20°C to carry out a substitution reaction between amine and Li, forming the compound of formula 11.
[0068] In the second step, a silicon precursor compound is formed by reacting it with a silane compound represented by formula 6. Then, the reaction product, the salt (LiCl), and unreacted substances are removed by filtration, and distillation is performed under reduced pressure to obtain a silicon precursor compound having a symmetrical structure represented by formula 3.
[0069] Another method for preparing the silicon precursor compound shown in reaction scheme 5 is carried out in the same manner as reaction scheme 4 above, wherein in reaction scheme 5, a third step is carried out in which the silicon precursor compound is reacted with a metal hydride (MH) as a reducing agent, when at least one of R2 and R4 in the silicon precursor compound represented by formula 3' of reaction scheme 3 is a halogen selected from fluorine (F), chlorine (Cl), bromine (Br), or iodine (I).
[0070] Preferably, when at least one of R2 and R4 in formula 3' is chlorine (Cl), the third step is carried out.
[0071] Nonpolar solvents used in reaction schemes 1-5 may include, but are not limited to, hexane and n-pentane. Any nonpolar solvent commonly used by those skilled in the art can be used.
[0072] The silicon precursor compound having a symmetrical structure is at least one selected from the following compounds (16) to (25). [ka]
[0073] In addition, in the method for preparing a silicon-containing thin film of the present invention, the silicon-containing thin film can be formed by chemical vapor deposition (CVD) or atomic layer deposition (ALD) using a silicon precursor compound represented by Formula 1.
[0074] The silicon-containing thin film may be any one selected from silicon oxide film (SiO2), silicon oxycarbide film (SiOC), silicon nitride film (SiN), silicon oxynitride film (SiON), silicon carbonitride film (SiCN), and silicon carbide film (SiC). [Examples]
[0075] Embodiments of the Invention The present invention will be described in more detail below with reference to examples.
[0076] [Example 1] In Example 1, dimethyltrimethylsilylhydrazinyltrimethylsilaneamine (3) was prepared as a silicon precursor compound having an asymmetric structure.
[0077] First, to prepare the silane compound necessary for the preparation of the silicon precursor compound, 360 g (3.13 mol) of dichloromethylsilane (CH3SiHCl2) and 4,516 g (62.59 mol) of n-pentane were placed in a 1-liter flask under an anhydrous inert atmosphere. While maintaining the temperature at approximately -20°C, 282 g (6.26 mol) of dimethylamine ((CH3)2NH) was slowly added to the flask and stirred for 3 hours. After stirring was complete, dimethylamine hydrochloride ((CH3)2NH2Cl) was removed by filtration, followed by removal of the solvent under reduced pressure and distillation to obtain 312 g (2.52 mol) of chlorodimethylaminomethylsilazane ((CH3)2NCH3SiHCl) (yield: 80%).
[0078] 1 H-NMR(C6D6):δ 0.23(d,3H(-SiCH3)),2.25(s,6H(-N(CH3)2)),5.0(m,1H(-SiH))
[0079] As the first step in the preparation of dimethyl(trimethylsilyl)hydrazine, 190 g (1.75 mol) of chlorotrimethylsilane ((CH3)3SiCl) and 3,387 g (46.94 mol) of n-pentane were placed in a 1-liter flask under an anhydrous inert atmosphere. While maintaining the temperature at approximately -20°C, 210 g (3.50 mol) of dimethylhydrazine ((CH3)2NNH2) was slowly added to the flask and stirred for 12 hours. After stirring was complete, dimethylhydrazine hydrochloride ((CH3)2NNH3Cl) was removed by filtration, followed by removal of the solvent under reduced pressure and distillation to obtain 161 g (1.22 mol) of dimethyl(trimethylsilyl)hydrazine ((CH3)2NNHSi(CH3)3) (yield: 70%).
[0080] 1 H-NMR(C6D6):δ 0.11(s,9H(-Si(CH3)3)),1.72(m,1H(-NHSi(CH3)2)),2.21(s,6H(-NN(CH3)2))
[0081] Next, in the second step, 76 g (0.58 mol) of dimethyl(trimethylsilyl)hydrazine ((CH3)2NNHSi(CH3)3) and 100 g (1.16 mol) of hexane were placed in a 1-liter flask under an anhydrous inert atmosphere. While maintaining the temperature at approximately -20°C, 245 ml (1.05 mol) of 2.5 M n-BuLi was slowly added to the flask, and then the reaction solution was gradually heated to room temperature and stirred at room temperature for 12 hours.
[0082] While maintaining the temperature of the mixed solution at approximately -20°C, 71 g (0.58 mol) of chlorodimethylaminomethylsilazane ((CH3)2NCH3SiHCl) was slowly added to the flask, and the mixture was stirred at room temperature for at least 6 hours. After stirring was complete, the lithium chloride (LiCl) salt was removed by filtration. The solvent was removed from the obtained solution under reduced pressure, and the solution was purified to obtain 101 g (yield: 80%) of dimethyltrimethylsilylhydrazinyltrimethylsilanamine ((CH3)2NCH3SiHN(CH3)2NSi(CH3)3).
[0083] Figure 1 shows the hydrogen nuclear magnetic resonance of a silicon precursor compound prepared according to Example 1 of the present invention. 1 The 1H-NMR spectrum is shown. As shown, the silicon precursor compound prepared in Example 1 was confirmed to be dimethyltrimethylsilylhydrazinyltrimethylsilaneamine.
[0084] 1 H-NMR(C6D6):δ 0.21(s,9H(-Si(CH3)3)),0.25(d,3H(-SiHCH3)),2.44(s,6H(-SiHCH3N(CH3)2)),2.51(s,6H(-NN(CH3)2)),4.90(m,1H(-SiHCH3N(CH3)2))
[0085] [Example 2] In Example 2, compound (9), dimethylsilyldimethylhydrazinyltrimethylsilaneamine, was prepared as a silicon precursor compound having an asymmetric structure.
[0086] As the first step in the preparation of (dimethylsilyl)dimethylhydrazine, 100 g (1.06 mol) of chlorodimethylsilane ((CH3)2SiHCl) and 100 ml of diethyl ether were placed in a 1 liter flask under an anhydrous inert atmosphere. While maintaining the temperature at approximately -20°C, 130.2 g (2.17 mol) of dimethylhydrazine ((CH3)2NNH2) was slowly added to the flask and stirred for 12 hours. After stirring was complete, dimethylhydrazine hydrochloride ((CH3)2NNH3Cl) was removed by filtration, followed by removal of the solvent under reduced pressure and distillation to obtain 85 g (0.72 mol) of (dimethylsilyl)dimethylhydrazine ((CH3)2NNHSiH(CH3)2) (yield: 68%).
[0087] 1 H-NMR(C6D6):δ 0.15(d,6H(-SiH(CH3)2)),1.77(s,1H(-NHSiH(CH3)2)),2.20(s,6H(-NN(CH3)2)),4.71(m,1H(-SiH(CH3)2))
[0088] Next, in the second step, 121 g (0.41 mol) of (dimethylsilyl)dimethylhydrazine ((CH3)2NNHSiH(CH3)2) and 108 g (0.82 mol) of hexane were placed in a 1-liter flask under an anhydrous inert atmosphere. While maintaining the temperature at approximately -20°C, 173.3 ml (0.43 mol) of 2.5 M n-BuLi was slowly added to the flask, and then the reaction solution was gradually heated to room temperature and stirred at room temperature for 12 hours.
[0089] While maintaining the temperature of the mixed solution at approximately -20°C, 71 g (0.41 mol) of chlorodimethylaminomethylsilazane ((CH3)2NCH3SiHCl) was slowly added to the flask, and the mixture was stirred at room temperature for at least 6 hours. After stirring was complete, the lithium chloride (LiCl) salt was removed by filtration. The solvent was removed from the obtained solution under reduced pressure, and the solution was purified to obtain 69 g (yield: 82%) of dimethylsilyldimethylhydrazinyltrimethylsilanamine ((CH3)2NCH3SiHN(CH3)2NSiH(CH3)2).
[0090] Figure 2 shows the hydrogen nuclear magnetic resonance of a silicon precursor compound prepared according to Example 2 of the present invention. 1 The 1H-NMR spectrum is shown. As shown, the silicon precursor compound prepared in Example 2 was confirmed to be dimethylsilyldimethylhydrazinyltrimethylsilaneamine.
[0091] 1 H-NMR(C6D6):δ 0.25(m,9H((CH3)2NCH3SiHN(CH3)2NSiH(CH3)2)),2.46(s,6H(-SiHCH3N(CH3)2)), 2.48(s,6H(-NN(CH3)2)),4.81(m,1H(-SiH(CH3)2)),4.82(m,1H(-SiHCH3N(CH3)2))
[0092] [Example 3] In Example 3, compound (18), bistrimethylsilaminodimethylhydrazine, was prepared as a silicon precursor compound having a symmetrical structure.
[0093] In a 1-liter flask in an anhydrous inert atmosphere, 100 g (1.63 mol) of dimethylhydrazine ((CH3)2NNH2) and 281 g (3.26 mol) of hexane were placed. While maintaining the temperature at about -20°C, 1,315 ml (3.26 mol) of 2.5 M n-BuLi was slowly added to the flask, and then the reaction solution was gradually heated to room temperature and stirred at room temperature for 12 hours.
[0094] While maintaining the temperature of the mixed solution at about -20°C, 403 g (3.26 mol) of chlorodimethylaminomethylsilazane ((CH3)2CH3NSiHCl) was slowly added to the flask and stirred at room temperature for 6 hours or more. After the stirring was completed, lithium chloride (LiCl) salt was removed by filtration. The solvent was removed from the resulting solution under reduced pressure and purified to obtain 268 g (yield: 70%) of bistrimethylsilylaminodimethylhydrazine ((CH3)2NSiHCH3)2NN(CH3)2).
[0095] Figure 3 shows the proton nuclear magnetic resonance ( 1 1H-NMR) spectrum of the silicon precursor compound prepared according to Example 3 of the present invention. As shown, it was confirmed that the silicon precursor compound prepared in Example 3 is bistrimethylsilylaminodimethylhydrazine.
[0096] 1 1H-NMR (C6D6): δ 0.30 (s, 6H (-SiHCH3N(CH3)2)2), 2.50 (m, 18H (((CH3)2NSiHCH3)2NN(CH3)2)), 4.79 (m, 2H ((CH3)2NSiHCH3)2NN-)
[0097] To analyze the thermal properties of the silicon precursor compounds prepared in Examples 1 to 3, thermogravimetric analysis (TGA) was performed. The results are shown in Figure 4.
[0098] As shown in Figure 4, it was confirmed that the silicon precursor compounds of Examples 1 to 3 are volatile even at temperatures below 200°C and are excellent precursors capable of forming silicon-containing thin films in a variety of temperature ranges.
[0099] The above results indicate that all of the silicon precursor compounds prepared according to Examples 1 to 3 are sufficiently volatile to be applied to atomic layer deposition (ALD) or chemical vapor deposition (CVD).
[0100] To confirm that the silicon precursor compounds prepared according to Examples 1 to 3 have a suitable vapor pressure for the preparation of silicon thin films by deposition, their vapor pressures were measured. The results are shown in Figure 5.
[0101] As shown in Figure 5, all of the silicon precursor compounds in Examples 1 to 3 exhibited a high vapor pressure of 10 Torr at approximately 90°C.
[0102] The vapor pressure results above indicate that all silicon precursor compounds prepared according to Examples 1 to 3 exhibited high vapor pressures at low temperatures of approximately 90°C or below, and that these vapor pressures are sufficient for application to atomic layer deposition (ALD) or chemical vapor deposition (CVD).
[0103] To evaluate silicon-containing thin films formed using silicon precursor compounds prepared according to the present invention, silicon nitride thin films were formed on a silicon substrate using atomic layer deposition (ALD) with bistrimethylsilaminodimethylhydrazine, the silicon precursor compound of Example 3. In this case, an ALD reactor was used in which the silicon precursor compound and reaction gas were supplied separately in a vertical direction using a double showerhead.
[0104] Table 1 and Figure 6 below show the specific conditions for depositing silicon nitride thin films. [Table 1]
[0105] The thickness of the thin films deposited using the method described above was confirmed using an ellipsometer. Table 2 and Figure 7 below show the results of the analysis of the properties of specific silicon nitride thin films. [Table 2]
[0106] As shown in Table 2, the N / Si composition ratio at a substrate temperature of 350°C indicates the formation of a high-purity silicon-containing thin film. In addition, Figure 7 is a graph showing the deposition rate of the silicon nitride film against substrate temperature. As shown in Figure 7, the deposition rate was similar under conditions of 250°C to 400°C.
[0107] In another example, to evaluate a silicon oxide thin film (SiO2) formed using a silicon precursor compound prepared according to the present invention, a silicon oxide thin film was formed on a silicon substrate using atomic layer deposition (ALD) with bistrimethylsilaminodimethylhydrazine, the silicon precursor compound of Example 3. In this case, an ALD reactor was used in which the silicon precursor compound and the reaction gas were supplied separately in a vertical direction using a double showerhead.
[0108] In this specification, SiN and SiO2 are prepared and described as representative silicon-containing thin films, but the invention is not limited to these. Silicon thin films known in the art, such as SiN, SiO2, SiON, SiCN, and SiC, can be formed.
[0109] Table 3 and Figure 8 below show the specific conditions for depositing silicon oxide thin films. [Table 3]
[0110] The silicon oxide thin films deposited in the manner described above were analyzed for their composition using X-ray photoelectron spectroscopy, and their step coverage was analyzed using a transmission electron microscope (TEM). Table 3 and Figure 9 below show the results of the analysis of the properties of specific silicon oxide thin films. [Table 4]
[0111] As shown in Table 4, the silicon oxide film formed using the silicon precursor compound of Example 3 had a thick film thickness of 120 Å. The O / Si composition ratio suggests that a high-purity silicon-containing thin film was formed.
[0112] Figure 9 is a graph showing the deposition rate of the silicon oxide film against substrate temperature. As shown in Figure 9, the deposition rate was similar in the temperature range of 300°C to 450°C.
[0113] Figure 10 is an image of the silicon oxide film deposited at a substrate temperature of 400°C, taken using a transmission electron microscope (TEM). As shown in Figure 10, the silicon oxide film was uniformly formed with a thickness of 120 Å.
[0114] Figure 11 shows the results of AES (Auger electron spectroscopy) analysis of the composition of silicon oxide films deposited at a substrate temperature of 400°C.
[0115] As described above, the silicon precursor compound prepared according to the present invention can form a high-purity, high-quality silicon oxide film at a high deposition rate.
[0116] The embodiments described above are merely for illustrating preferred embodiments of the present invention. The scope of the present invention is not limited to the embodiments described. Various changes, modifications, and substitutions are possible within the technical spirit and claims of the present invention for those skilled in the art. It should be understood that such embodiments fall within the scope of the present invention.
Claims
1. A silicon precursor compound, wherein the following formula (1), [Formula 1] 【Chemistry 1】 (In Formula 1, R １ is each independently a linear or branched saturated or unsaturated hydrocarbon group having 1 to 4 carbon atoms, or an isomer thereof, and R ２ to R ５ are each independently hydrogen (H), a halogen, or a linear or branched saturated or unsaturated hydrocarbon group having 1 to 4 carbon atoms, and A and A' are each independently NR ６ R ７ or R ８ provided that at least one of A and A' is NR ６ R ７ and R ６ and R ７ are each independently a methyl group or an ethyl group, and R ８ is hydrogen (H), a halogen, or a linear or branched saturated or unsaturated hydrocarbon group having 1 to 4 carbon atoms). A silicon precursor compound represented by
2. The silicon precursor compound is given by the following formula 2, [Formula 2] 【Chemistry 2】 (In formula 2, R １ Each is independently a linear or branched saturated or unsaturated hydrocarbon group having 1 to 4 carbon atoms, or an isomer thereof, R ２ ~R ５ Each is independently a hydrogen (H), a halogen, or a linear or branched saturated or unsaturated hydrocarbon group having 1 to 4 carbon atoms, R ６ and R ７ Each is independently a methyl group or an ethyl group, R ８ The silicon precursor compound according to claim 1, having an asymmetric structure represented by hydrogen (H), a halogen, or a linear or branched saturated or unsaturated hydrocarbon group having 1 to 4 carbon atoms.
3. The silicon precursor compound is given by the following formula 3, [Formula 3] 【Transformation 3】 (In formula 3, R １ Each is independently a linear or branched saturated or unsaturated hydrocarbon group having 1 to 4 carbon atoms, or an isomer thereof, R ２ and R ４ Each is independently a hydrogen (H), a halogen, or a linear or branched saturated or unsaturated hydrocarbon group having 1 to 4 carbon atoms, R ６ and R ７ The silicon precursor compound according to claim 1, having a symmetric structure represented by (each independently being a methyl group or an ethyl group).
4. The silicon precursor compound according to claim 1, wherein the silicon precursor compound is at least one selected from the following compounds (1) to (25). 【Chemistry 4】 【Transformation 5】
5. A method for preparing silicon precursor compounds, A first step involves reacting a chlorosilane derivative with a hydrocarbylhydrazine compound to form a first compound, A second step involves reacting the first compound with alkyl-lithium (alkyl-Li) to form a second compound containing lithium, The second compound is reacted with a silane compound to obtain the following compound 2, [Formula 2] 【Transformation 6】 (In formula 2, R １ Each is independently a linear or branched saturated or unsaturated hydrocarbon group having 1 to 4 carbon atoms, or an isomer thereof, R ２ ~R ５ Each is independently a hydrogen (H), a halogen, or a linear or branched saturated or unsaturated hydrocarbon group having 1 to 4 carbon atoms, R ６ and R ７ Each is independently a methyl group or an ethyl group, R ８ A method for preparing a silicon precursor compound, comprising: a third step of preparing a silicon precursor compound represented by hydrogen (H), a halogen, or a linear or branched saturated or unsaturated hydrocarbon group having 1 to 4 carbon atoms.
6. The first compound is given by the following formula 9, [Formula 9] 【Transformation 7】 (In formula 9, R １ Each is independently a linear or branched saturated or unsaturated hydrocarbon group having 1 to 4 carbon atoms, or an isomer thereof, R ３ , R ５ , and R ８ A method for preparing a silicon precursor compound according to claim 5, wherein each of the compounds is independently represented by hydrogen (H), a halogen, or a linear or branched saturated or unsaturated hydrocarbon group having 1 to 4 carbon atoms.
7. R in the silicon precursor compound represented by the above formula 2 ２ and R ４ A method for preparing a silicon precursor compound according to claim 5, wherein, when at least one of the elements is a halogen, the method further comprises a fourth step of reacting the silicon precursor compound with a metal hydride as a reducing agent.
8. A method for preparing the silicon precursor compound according to claim 5, wherein the silane compound is produced by reacting a chlorosilane derivative with a secondary amine.
9. A method for preparing silicon precursor compounds, A first step involves reacting a hydrocarbylhydrazine compound with alkyl-lithium (alkyl-Li) to form a third compound containing lithium, The third compound is reacted with a silane compound to obtain the following formula 3, [Formula 3] 【Transformation 8】 (In formula 3, R １ Each is independently a linear or branched saturated or unsaturated hydrocarbon group having 1 to 4 carbon atoms, or an isomer thereof, R ２ and R ４ Each is independently a hydrogen (H), a halogen, or a linear or branched saturated or unsaturated hydrocarbon group having 1 to 4 carbon atoms, R ６ and R ７ A method for preparing a silicon precursor compound, comprising: a second step of preparing a silicon precursor compound represented by (where each is independently a methyl group or an ethyl group).
10. The third compound is given by the following formula 11, [Formula 11] 【Chemistry 9】 (In formula 11, R １ A method for preparing a silicon precursor compound according to claim 9, wherein each of the compounds is independently represented by a linear or branched saturated or unsaturated hydrocarbon group having 1 to 4 carbon atoms, or an isomer thereof.
11. R in the silicon precursor compound represented by formula 3 ２ and R ４ A method for preparing a silicon precursor compound according to claim 9, wherein, when at least one of the elements is a halogen, the method further comprises a third step of reacting the silicon precursor compound with a metal hydride as a reducing agent.
12. A method for preparing the silicon precursor compound according to claim 9, wherein the silane compound is produced by reacting a chlorosilane derivative with a secondary amine.
13. A method for preparing a silicon-containing thin film, wherein the following formula 1, [Formula 1] 【Chemistry 10】 (In formula 1, R １ Each is independently a linear or branched saturated or unsaturated hydrocarbon group having 1 to 4 carbon atoms, or an isomer thereof, R ２ ~R ５ Each is independently hydrogen (H), a halogen, or a linear or branched saturated or unsaturated hydrocarbon group having 1 to 4 carbon atoms, and A and A' are each independently NR ６ R ７ or R ８ However, at least one of A and A' is NR ６ R ７ And R ６ and R ７ Each is independently a methyl group or an ethyl group, R ８ A method for preparing a silicon-containing thin film, comprising forming a silicon-containing thin film using a silicon precursor compound represented by hydrogen (H), a halogen, or a linear or branched saturated or unsaturated hydrocarbon group having 1 to 4 carbon atoms.
14. A method for preparing a silicon-containing thin film according to claim 13, wherein the silicon precursor compound is at least one selected from the following compounds (1) to (25). 【Chemistry 11】 【Chemistry 12】
15. A method for preparing the silicon-containing thin film according to claim 13, wherein the silicon-containing thin film is deposited by chemical vapor deposition or atomic layer deposition.
16. The silicon-containing thin film is a silicon oxide film (SiO ２ A method for preparing a silicon-containing thin film according to claim 13, wherein the silicon film is one selected from ), silicon oxynitride film (SiOC), silicon nitride film (SiN), silicon oxynitride film (SiON), silicon carbonitride film (SiCN), and silicon carbide film (SiC).
17. The silicon-containing thin film is a silicon oxide film (SiO ２ ) and The silicon oxide film is deposited by atomic layer deposition. A method for preparing a silicon-containing thin film according to claim 15, wherein the atomic layer deposition comprises providing a substrate in a reactor, introducing the silicon precursor compound into the reactor, purging the reactor with a purge gas, introducing an oxygen-containing source into the reactor and reacting it with the silicon precursor compound to form a silicon oxide film, and purging the reactor with the purge gas.
18. The purge gas is selected from the group consisting of nitrogen, helium, argon, and mixtures thereof. A method for preparing a silicon-containing thin film according to claim 17, wherein the oxygen-containing source is selected from the group consisting of oxygen, peroxide, oxygen plasma, water vapor, water vapor plasma, hydrogen peroxide, ozone source, and mixtures thereof.
19. A method for preparing a silicon-containing thin film according to claim 17, wherein the oxygen-containing source includes plasma.
20. A method for preparing a silicon-containing thin film according to claim 19, wherein the plasma is generated in situ.
21. A method for preparing a silicon-containing thin film according to claim 17, wherein the atomic layer deposition is carried out at one or more temperatures of 500°C or less.
22. The silicon-containing thin film is a silicon nitride film (SiN), The silicon nitride film is deposited by plasma-enhanced atomic layer deposition. A method for preparing a silicon-containing thin film according to claim 15, wherein the plasma-enhanced atomic layer deposition comprises providing a substrate in a reactor, introducing the silicon precursor compound into the reactor, purging the reactor with a purge gas, introducing a nitrogen-containing plasma source and an inert gas into the reactor and reacting them with the silicon precursor compound to form a silicon nitride film, and purging the reactor with the purge gas.
23. The nitrogen-containing plasma source is a nitrogen plasma, a nitrogen and argon mixed plasma, an ammonia plasma, a nitrogen and ammonia mixed plasma, an ammonia and helium mixed plasma, an ammonia and argon mixed plasma, an ammonia and nitrogen mixed plasma, NF ３ A method for preparing a silicon-containing thin film according to claim 22, selected from the group consisting of plasma, organic amine plasma, and mixtures thereof.
24. A method for preparing a silicon-containing thin film according to claim 22, wherein the plasma-enhanced atomic layer deposition is carried out at one or more temperatures of 400°C or lower.