KR20240001544A - Organo tin compound for thin film deposition, method of forming the same and method of forming tin containing thin film using the same - Google Patents

Abstract

According to an embodiment of the present invention, the organic tin compound is represented by the following formula (1), and is used as a precursor when depositing a tin-containing thin film to provide a high-quality tin-containing thin film.
[Formula 1]

In Formula 1, R ₁ to R ₄ are each independently a linear alkyl group having 1 to 6 carbon atoms or a branched alkyl group having 3 to 6 carbon atoms.

Description

Organic tin compound for thin film deposition, method for producing same, and method for forming tin-containing thin film using same {ORGANO TIN COMPOUND FOR THIN FILM DEPOSITION, METHOD OF FORMING THE SAME AND METHOD OF FORMING TIN CONTAINING THIN FILM USING THE SAME}

The present invention relates to an organic tin compound, a method for producing the same, and a method for forming a tin-containing thin film using the same. More specifically, the present invention relates to an organic tin compound that is used as a precursor for thin film deposition and can provide a high-quality tin-containing thin film. , a manufacturing method thereof, and a method of forming a tin-containing thin film using the same.

Due to the advancement of electronic technology, the demand for miniaturization and weight reduction of electronic devices used in various electronic devices is rapidly increasing. Accordingly, various physical and chemical deposition methods have been proposed to form microscopic electronic devices. Research is being actively conducted to form various types of metal thin films, such as metal thin films, metal oxide thin films, and metal nitride thin films, using these deposition methods, and to manufacture various semiconductor devices therefrom.

In the manufacture of semiconductor devices, metal-containing thin films are generally formed using a metal organic chemical vapor deposition (MOCVD) or atomic layer deposition (ALD) process. The ALD deposition process has a self-limiting reaction, so it has superior step coverage compared to the MOCVD deposition process, and because it is a relatively low-temperature process, it has the advantage of avoiding deterioration of device characteristics due to thermal diffusion.

In order to form high-quality metal-containing thin films through MOCVD or ALD deposition processes, precursor compounds must meet various physical properties such as appropriate and robust thermal stability, high reactivity, high vapor pressure, and long-term stability. In addition, it must be possible to form a thin film with uniform thickness and excellent physical properties in a microscopic three-dimensional structure.

Meanwhile, the Sn-C bond of alkyl tin compounds, which are widely known organic tin compounds, has the advantage of being radiation sensitive and making it easy to pattern structures using lithography. However, electronic devices are gradually becoming smaller and finer, and the development of a suitable organic tin precursor that can form a thin film of uniform thickness even in a miniaturized three-dimensional structure is insufficient.

The purpose of the present invention is to provide an organic tin compound that is suitable for thin film growth, has solid thermal stability, has a high vapor pressure, exists in a liquid state at room temperature, and is easy to store and handle, and a method for producing the same.

In addition, the purpose of the present invention is to provide a method of forming a tin-containing thin film that can provide a tin-containing thin film with uniform thickness and excellent film quality through a deposition process using the organic tin compound.

The problems of the present invention are not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the description below.

The organic tin compound according to an embodiment of the present invention may be represented by Formula 1.

[Formula 1]

In Formula 1, R ₁ to R ₄ are each independently a linear alkyl group having 1 to 6 carbon atoms or a branched alkyl group having 3 to 6 carbon atoms.

The method for producing an organic tin compound according to an embodiment of the present invention is to react a tin (IV) chloride (SnCl ₄ ) compound with an alkyl magnesium halide compound represented by Formula A to produce a monoalkyl tin trihalide compound represented by Formula B. It includes a first step of preparing a compound represented by the following formula (1) by reacting a monoalkyl tin trihalide compound with an alcohol in the presence of a base catalyst.

[Formula A] R ₁ MgX

[Formula B] Sn(R ₁ )Cl ₃

In formulas A and B, R ₁ is a linear alkyl group having 1 to 6 carbon atoms or a branched alkyl group having 3 to 6 carbon atoms, and in formula A, X is Cl or Br.

[Formula 1]

In Formula 1, R ₁ to R ₄ are each independently a linear alkyl group having 1 to 6 carbon atoms or a branched alkyl group having 3 to 6 carbon atoms, and R ₂ to R ₄ are an alkyl group derived from the second stage alcohol.

A method of forming a tin-containing thin film according to an embodiment of the present invention includes depositing a thin film on a substrate using the organic tin compound represented by Formula 1 above as a precursor.

Specific details of other embodiments are included in the detailed description and drawings.

The organic tin compound according to an embodiment of the present invention has excellent thermal stability and exists in a liquid state at room temperature, making it easy to store and handle.

In addition, the organotin compound according to an embodiment of the present invention has high volatility, so it is easy to vaporize the organotin compound during the thin film formation process, and there is an advantage that the vaporized compound is easy to transport and supply to the reaction chamber.

In addition, the organic tin compound of the present invention has excellent reactivity and can form a high-quality tin thin film at a rapid growth rate when forming a thin film.

In addition, the organic tin compound of the present invention effectively reduces the amount of residue in the deposition process and can form a tin thin film of uniform thickness.

Accordingly, a high-quality tin thin film can be stably formed on a substrate through an atomic layer deposition process or a metal-organic chemical vapor deposition process using the organic tin compound of the present invention as a precursor.

Due to the effects of the above invention, it is possible to form a thin film of uniform thickness on the surface of a miniaturized three-dimensional structure by using the organic tin compound of the present invention as a precursor, and further contribute to the manufacture of nanoscale semiconductor devices.

The effects according to the present invention are not limited to the details exemplified above, and further various effects are included within the present invention.

Figure 1 is a graph showing the results of nuclear magnetic resonance analysis ( ^1H NMR) of the compound according to Example 1.
Figure 2 is a graph showing the results of thermogravimetric analysis (TGA) of the compound according to Example 1.
Figure 3 is a graph showing the results of thermogravimetric analysis (TGA) of the compound according to Comparative Example 1.
Figure 4 is a graph showing the results of differential scanning calorimetry (DSC) of the compound according to Example 1.
Figure 5 is a graph showing the results of differential scanning calorimetry (DSC) of the compound according to Comparative Example 1.
Figure 6 is a photograph showing the results of evaluating the thermal stability of the compound according to Example 1 and Comparative Example 1.
Figure 7 is a graph showing the results of X-ray photoelectron spectroscopy analysis of the tin oxide thin film according to Example 1.
Figure 8 is a graph showing the results of X-ray photoelectron spectroscopy analysis of the tin oxide thin film according to Comparative Example 1.

The advantages and features of the present invention and methods for achieving them will become clear by referring to the embodiments described in detail below along with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below and will be implemented in various different forms, and only the present embodiments make the disclosure of the present invention complete, and are known to those skilled in the art in the technical field to which the present invention pertains. It is provided to fully inform those who have the scope of the invention, and the present invention is only defined by the scope of the claims.

In describing the present invention, if it is determined that a detailed description of related known technologies may unnecessarily obscure the gist of the present invention, the detailed description will be omitted. When 'comprises', 'has', 'consists of', etc. mentioned in the present invention are used, other parts may be added unless 'only' is used. When a component is expressed in the singular, the plural is included unless specifically stated otherwise.

When interpreting a component, it is interpreted to include the margin of error even if there is no separate explicit description.

Throughout this specification, the term “room temperature” means a temperature of 15°C to 30°C.

Throughout this specification, the hydrogen atoms of the compounds may be replaced with a selection of the isotopes light hydrogen, deuterium, and tritium.

Throughout this specification, unless otherwise stated, percentages are based on weight.

The organic tin compound according to an embodiment of the present application may be represented by the following formula (1).

[Formula 1]

In Formula 1, R ₁ to R ₄ are each independently a linear alkyl group having 1 to 6 carbon atoms or a branched alkyl group having 3 to 6 carbon atoms.

The organotin compound of Formula 1 contains one Sn-C bond and three Sn-O bonds. In this case, because of its excellent thermal stability and reactivity, a tin-containing thin film can be easily formed through a chemical vapor deposition or atomic layer deposition process.

In particular, the Sn-O bond of the organotin compound of Formula 1 has a higher bonding energy than the Sn-N bond of conventional organotin compounds, so it has the advantage of being thermally stable.

In addition, as shown in Formula 1, organotin compounds containing alkoxy ligands have superior reactivity compared to existing organotin compounds containing amine ligands, and thus hydrolysis and condensation reactions occur more easily during the deposition process, resulting in lower residue content. A high-quality tin-containing thin film can be obtained.

Accordingly, when the organotin compound of Formula 1 is used as a precursor for the thin film deposition process, a uniform thickness can be achieved on a complex and refined structure compared to the conventional organotin compound consisting only of Sn-C bonds or the organotin compound containing Sn-N bonds. and a tin-containing thin film having film quality can be formed.

In Formula 1, R ₁ to R ₄ may each independently be a branched alkyl group having 3 to 6 carbon atoms. In this case, the structural and chemical stability of the organotin compound is excellent. Additionally, in the deposition process for forming a tin-containing thin film, vaporization of the precursor compound is easy, providing a process advantage.

In Formula 1, R ₂ , R ₃ and R ₄ may be the same as each other. In this case, when a deposition process is performed using the organotin compound of Formula 1 as a precursor, side reactions are suppressed during the deposition process and the residue content is reduced, so that a high-quality tin-containing thin film can be obtained.

More specifically, for example, the organic tin compound may be a compound represented by the following formula (2).

[Formula 2]

The organic tin compound according to an embodiment of the present invention can maintain a more structurally stable state and thus has excellent thermal stability. Accordingly, the organic tin compound according to an embodiment of the present invention can be used as a precursor composition for depositing a tin-containing thin film. Therefore, a high-quality tin thin film can be stably formed through an atomic layer deposition process or a metal-organic chemical vapor deposition process using the organic tin compound according to an embodiment of the present invention as a precursor.

Additionally, the organic tin compound according to an embodiment of the present invention exists in a liquid state at room temperature. Accordingly, it is easy to store and handle, and has high volatility, making it advantageous for application to the thin film formation process. When forming a thin film through a deposition process, the precursor material must be able to be easily transferred to the reaction chamber without being decomposed. The organic tin compound according to an embodiment of the present invention is thermally stable and does not decompose, exists in a liquid state at room temperature, and has a high vapor pressure, so it can be advantageously used in a thin film deposition process.

Additionally, the organic tin compound according to an embodiment of the present invention has excellent reactivity with a reaction gas during the deposition process. Accordingly, when forming a thin film, it grows at a rapid rate, allowing the formation of a high-quality tin-containing thin film. Accordingly, it is easy to form not only tin thin films but also various types of tin-containing thin films selected from tin oxide thin films, tin carbon oxide thin films, and tin nitride thin films.

In addition, the organotin compound of Formula 1 has excellent thermal stability, so it has the advantage of being able to be deposited over a wide temperature range from low to high temperatures. Additionally, side reactions are suppressed during the deposition process, and the amount of residue generated as the ligand is removed can be reduced. Accordingly, a high-quality tin-containing thin film with low residue content and high density can be formed.

Furthermore, by using the organic tin compound according to an embodiment of the present invention as a precursor, it is possible to easily form a tin-containing thin film with uniform thickness and excellent film quality even on the surface of a complex and refined three-dimensional structure.

Hereinafter, a method for producing an organic tin compound according to an embodiment of the present invention will be described.

The method for producing an organic tin compound includes a first step of reacting a tin(IV) chloride (SnCl ₄ ) compound with an alkyl magnesium halide compound to produce a monoalkyl tin trihalide compound, and reacting a monoalkyl tin trihalide compound with an alcohol under a base catalyst. It includes a second step of reacting to produce a compound represented by the following formula (1).

In the first step, the tin chloride compound and the alkyl magnesium halide compound may be reacted in an organic solvent. For example, the organic solvent may be selected from diethyl ether, tetrahydrofuran, dibutyl ether, hexane, benzene, toluene, cyclohexane, chlorobenzene, etc.

For example, the alkyl magnesium halide compound may be a compound represented by the following formula (A).

[Formula A]

_R1MgX

In Formula A, R ₁ is a linear alkyl group having 1 to 6 carbon atoms or a branched alkyl group having 3 to 6 carbon atoms. Since R ₁ in Formula 1 is an alkyl group derived from R ₁ in Formula A, R ₁ in Formula 1 and Formula A are the same.

In Formula A, X is a halide group. For example, X can be selected from fluorine (F), chlorine (Cl), bromine (Br), and iodine (I). Preferably, for example, X may be chlorine (Cl) or bromine (Br). In this case, side reactions can be minimized and product yield is excellent.

The alkyl magnesium halide compound is an alkylating agent, and can react with a tin(IV) chloride (SnCl ₄ ) compound to produce a monoalkyl tin trihalide compound by transferring the alkyl group R ₁ .

Monoalkyl tin trihalide compounds are represented by formula B.

[Formula B]

Sn(R ₁ )Cl ₃

In Formula B, R ₁ is a linear alkyl group having 1 to 6 carbon atoms or a branched alkyl group having 3 to 6 carbon atoms. R ₁ in Formula B is the same as R ₁ in Formula A.

The addition of the alkyl magnesium halide compound in the first step may be performed at -30°C to -60°C, and the reaction in the first step may be performed at 15°C to 50°C or 15°C to 30°C. Within this range, reactivity and yield are excellent.

When the reaction in the first step is completed, the reaction product is purified to obtain a monoalkyl tin trihalide compound represented by Formula B.

The second step is a step of reacting the monoalkyl tin trihalide compound obtained as above with alcohol under a base catalyst. The reaction of the monoalkyl tin trihalide compound with the alcohol can be carried out in an organic solvent. For example, the organic solvent may be selected from diethyl ether, tetrahydrofuran, dibutyl ether, hexane, benzene, toluene, cyclohexane, chlorobenzene, etc.

For example, the base catalyst may be one or more selected from triethylamine and diisopropylethylamine, but is not limited thereto.

Through the second step reaction, an organic tin compound in which an alkoxy ligand is bonded to tin may be formed.

For example, alcohol is represented by the formula R'OH, where R' may be a linear alkyl group having 1 to 6 carbon atoms or a branched alkyl group having 3 to 6 carbon atoms.

Specifically, for example, the alcohol may be one or more selected from methanol, ethanol, n-butanol, iso-butanol, tert-butanol, 1-propanol, etc.

R ₂ to R ₄ in Formula 1 are alkyl groups derived from the alkyl group R' contained in alcohol. When only one type of alcohol is used in the second step, R ₂ to R ₄ in Formula 1 are all the same. When introducing an alkoxy group step by step using two or more alcohols of different types of alkyl group R', R ₂ to R ₄ may be different from each other.

The addition of the base catalyst in the second step may be performed at -80°C to -50°C, and the reaction in the second step may be performed at 15°C to 50°C or 15°C to 30°C. Within this range, reactivity and yield are excellent.

After the second step reaction is completed, the reaction product is purified to obtain an organic tin compound represented by Formula 1.

The organic tin compound thus obtained can be used as a precursor in a deposition process to form a tin-containing thin film. Hereinafter, a method of forming a tin-containing thin film according to an embodiment of the present invention will be described.

A method of forming a tin-containing thin film according to an embodiment of the present invention includes depositing a thin film on a substrate through a deposition process using an organic tin compound represented by Formula 1 as a precursor. If necessary, an organic tin compound may be dissolved in a solvent and used.

For example, the deposition process may be a Metal Organic Chemical Vapor Deposition (MOCVD) process or an Atomic Layer Deposition (ALD) process.

For example, the deposition process may be carried out at a temperature ranging from 100°C to 1000°C. Preferably, the deposition process may be carried out in a temperature range of 150°C to 400°C. In this case, the hydrolysis and condensation reactions of the organic tin precursor proceed stably, the residue content can be minimized, and a high-quality tin-containing thin film can be obtained.

The step of depositing a thin film includes transferring the organic tin compound represented by Formula 1 to a reaction chamber equipped with a substrate.

For example, the organotin compound of Formula 1 can be manufactured using a bubbling method, a vapor phase mass flow controller method, a direct gas injection (DGI) method, or a direct liquid injection (Direct Liquid Injection) method. It may be supplied on the substrate by a DLI) method, a liquid transfer method in which the material is transported by dissolving it in an organic solvent, etc., but is not limited thereto.

If necessary, the organic tin compound can be supplied with a carrier gas or diluent gas. The carrier gas has no reactivity with the organic tin compound and is lighter than the organic tin compound, so it easily transports the vaporized organic tin compound to the reaction chamber. The dilution gas is not reactive with the organic tin compound, so it does not cause side reactions, and by controlling its flow rate, reactions such as the growth rate of the thin film can be easily controlled. For example, each of the carrier gas and dilution gas may be one or more selected from argon (Ar), nitrogen (N ₂ ), helium (He), and hydrogen (H ₂ ).

For example, the organic tin compound is mixed with a carrier gas or dilution gas containing one or more selected from argon (Ar), nitrogen (N ₂ ), helium (He), and hydrogen (H ₂ ), and bubbles. It can be transferred onto the substrate by ring or direct gas injection.

A tin thin film can be formed by depositing an organic tin compound, and a reaction gas can be supplied as needed to form various tin-containing thin films, such as a tin oxide thin film, a tin carbon oxide thin film, and a tin nitride thin film. The reaction gas may be supplied in the step of depositing the thin film.

For example, when attempting to manufacture a tin oxide thin film or a tin carbon oxide thin film, a reaction gas containing oxygen can be supplied. For example, the reaction gas containing oxygen may include one or more selected from water vapor (H ₂ O), oxygen (O ₂ ), oxygen plasma, ozone (O ₃ ), and hydrogen peroxide (H ₂ O ₂ ). This reaction gas can react with an organic tin compound in a thin film deposition process to form a tin oxide thin film or a tin carbon oxide thin film.

As another example, when attempting to manufacture a tin nitride thin film, a reaction gas containing nitrogen can be supplied. For example, the reaction gas containing nitrogen may include one or more selected from ammonia (NH ₃ ), hydrazine (N ₂ H ₄ ), nitrous oxide (N ₂ O), and nitrogen (N ₂ ). This reaction gas can react with an organic tin compound in a thin film deposition process to form a tin nitride thin film.

After the organotin compound of Formula 1 is supplied onto the substrate, decomposition and condensation reactions of the organotin compound proceed when heat energy, plasma, electrical bias, etc. are applied, thereby forming a tin-containing thin film.

Once a thin film of the desired thickness is formed, the reaction chamber is purged with an inert gas such as argon (Ar), nitrogen (N ₂ ), helium (He), and/or hydrogen (H ₂ ) to remove the remaining unreacted organic matter. A step of removing tin compounds may be included.

The organic tin compound according to an embodiment of the present invention has excellent structural stability and thermal stability. Accordingly, a tin-containing thin film formed through MOCVD deposition or ALD deposition using the organic tin compound as a precursor has the advantage of excellent step coverage, uniform film thickness, and high density.

In addition, the organic tin compound exists in a liquid state at room temperature, making it easy to handle, and is easily volatilized without thermal decomposition, making it easy to transport and supply to a chamber for thin film deposition.

In addition, the ligand of the organic tin compound is easily removed during the thin film deposition process, which has the advantage of greatly reducing the content of residues in the thin film.

Furthermore, when the organic tin compound according to an embodiment of the present invention is used as a precursor for the deposition process, a tin-containing thin film of excellent quality and uniform thickness can be formed on a complex and microscopic three-dimensional substrate.

Hereinafter, the organic tin compound according to the present invention and the tin-containing thin film formed using the same will be described in more detail through the following examples. However, this is only presented to aid understanding of the present invention, and the present invention is not limited to the following examples.

[Example 1]

1. Preparation of (tert-Bu)Sn(O-tert-Bu) ₃

300 ml of diethyl ether was added to a 1000 ml flask, and 50.0 g (0.1919 mol) of SnCl ₄ was slowly added at about -50°C. 100.77 ml (0.2015 mol) of tert-Butyl magnesium chloride dissolved in diethyl ether was added to a 500 ml dropping funnel and slowly added to the SnCl ₄ solution at about -50°C. Next, the temperature of the solution was raised to room temperature and stirred for 8 hours to react. The reaction product was filtered and depressurized to remove the solvent and by-products, and monobutyl tin trichloride [(tert-Bu)Sn(Cl) ₃ ] was obtained. (yield: 83%)

45 g (0.159 mol) of [(tert-Bu)Sn(Cl) ₃ ] and 400 ml of diethyl ether were added to a 1000 ml flask and mixed. 50 g (0.494 mol) of triethylamine was slowly added at about -70°C, then the temperature was raised to room temperature and stirred for 1 hour. 36.05 g (0.486 mol) of tert-butanol was slowly added through a 250 ml dropping funnel, and the reaction was stirred for 12 hours. The reaction product was filtered and reduced pressure to remove solvent and by-products. Next, the product was purified at 60°C and under a pressure of 0.13 Torr to obtain 45 g of the compound represented by Formula 2 [(tert-Bu)Sn(O-tert-Bu) ₃ ]. (yield: 71%)

Nuclear magnetic resonance analysis ( ¹ H NMR) (solvent: C ₆ D ₆ used) was performed to confirm the synthesis of the compound, and the results are attached to FIG. 1. Based on the nuclear magnetic resonance analysis results shown in Figure 1, the synthesis of the compound represented by Formula 2 was confirmed.

2. Fabrication of tin oxide thin films

A tin oxide thin film was deposited on a silicon substrate by chemical vapor deposition using the compound [(tert-Bu)Sn(O-tert-Bu) ₃ ] prepared above as a precursor. The organic tin compound was placed in a bubbler type canister, and the canister was heated to 60°C to 100°C to ensure smooth supply. Water vapor (H ₂ O) was used as the reaction gas, and its temperature was adjusted to 5°C to 25°C. A thermal type chamber was used as the reaction chamber, and organic tin compounds and reaction gas were supplied through a showerhead. At this time, the showerhead temperature was heated to 110°C, and the stage temperature was heated to 50°C to 200°C. A silicon substrate was placed inside the reaction chamber, an organic tin compound precursor and water vapor were supplied to the reaction chamber using argon gas as a carrier gas, and a tin oxide thin film was deposited. At this time of deposition, the thickness of the thin film was controlled by adjusting the deposition time.

[Comparative Example 1]

1. Preparation of (tert-Bu)Sn[N(CH ₃ ) ₂ ] ₃

In a 1000 ml flask, 188.27 ml (0.466 mol) of n-butyl lithium solution dissolved in n-hexane and 300 ml of n-hexane were added and mixed. 21.8 g (0.483 mol) of dimethylamine was slowly added at about -50°C, the temperature was raised to room temperature, and the reaction was stirred for 5 hours. Next, 30.0 g (0.115 mol) of SnCl ₄ was slowly added at about -30°C. Next, the temperature of the reactant was raised to room temperature and the reaction was stirred for 12 hours. The reaction product was filtered and reduced pressure to remove solvent and by-products. Next, the product was purified at 50°C and a pressure of 0.3 Torr to obtain 27g of intermediate Sn[N(CH ₃ ) ₂ ] ₄ . (yield: 80%)

27 g (0.091 mol) of intermediate Sn[N(CH ₃ ) ₂ ] ₄ and 200 ml of diethyl ether were added to a 1000 ml flask and mixed. 48.05 ml (0.096 mol) of tert-Butyl magnesium chloride dissolved in tetrahydrofuran was slowly added at about -70°C. The temperature of the reactant was raised to room temperature, and the reaction was stirred for 8 hours. The reaction product was filtered and depressurized to remove the solvent and by-products, and then purified under a pressure of 0.2 Torr at 75°C to obtain 14g of (tert-Bu)Sn[N(CH ₃ ) ₂ ] ₃ . (Yield: 49%)

2. Fabrication of tin oxide thin films

A tin oxide thin film was formed on a silicon substrate using the same method and conditions as in Example 1, except that the compound (tert-Bu)Sn[N(CH ₃ ) ₂ ] ₃ prepared according to Comparative Example 1 was used as a precursor. deposited.

[Experimental Example 1]

Thermogravimetric analysis (TGA) was performed on the compound of Chemical Formula 2 prepared in Example 1 and (tert-Bu)Sn[N(CH ₃ ) ₂ ] ₃ in Comparative Example 1. Thermogravimetric analysis was performed by placing a sample of a predetermined weight in a crucible, raising the temperature from room temperature to 350°C at a rate of 10°C/min, and injecting argon gas at a pressure of 1.5 bar/min. The results are shown in Figures 2 and 3. Figure 2 is a graph showing the results of thermogravimetric analysis (TGA) of the compound according to Example 1, and Figure 3 is a graph showing the results of thermogravimetric analysis (TGA) of the compound according to Comparative Example 1.

Referring to FIG. 2, the compound of Example 1 was confirmed to have a mass decrease starting from about 100°C, and the final residue content was confirmed to be 0.09% at 350°C. In addition, it was confirmed that the half-life (T _1/2 ) of the compound of Example 1 was about 159.66°C. Meanwhile, referring to Figure 3, it was confirmed that the compound of Comparative Example 1 had a mass decrease starting from about 50°C, the final residue content was 0.396%, and the half-life was 145.92°C. As can be seen in Figures 2 and 3, the mass of the compound of Example 1 begins to decrease at a much higher temperature than that of the compound of Comparative Example 1, and the half-life is about 13.7°C higher while the residue content is much lower. From this, it can be seen that when the compound according to Example 1 is used as a precursor for the deposition process, a high-quality tin-containing thin film with excellent thermal stability and low residue content can be formed.

[Experimental Example 2]

Differential scanning calorimetry (DSC) was performed on the compound of Formula 2 prepared in Example 1 and (tert-Bu)Sn[N(CH ₃ ) ₂ ] ₃ in Comparative Example 1. Differential scanning calorimetry was measured while heating the sample to 400°C at a rate of 10°C/min. The results are shown in Figures 4 and 5. Figure 4 is a graph showing the results of differential scanning calorimetry (DSC) of the compound according to Example 1, and Figure 5 is a graph showing the results of differential scanning calorimetry (DSC) of the compound according to Comparative Example 1. During differential scanning calorimetry analysis, the thermal decomposition temperature was determined as the starting point of the exothermic peak.

Referring to Figures 4 and 5, it can be confirmed that thermal decomposition of the compound of Example 1 occurs at 307.85°C, and that thermal decomposition of the compound of Comparative Example 1 begins at about 202.84°C. The thermal decomposition temperature of the compound according to Example 1 is more than 105°C higher than that of the compound according to Comparative Example 1, and from this, it can be seen that the compound of Example 1 is very thermally stable.

[Experimental Example 3]

The thermal stability of the compound according to Example 1 and the compound of Comparative Example 1 was evaluated. For thermal stability evaluation, each of the compounds of Example 1 and Comparative Example 1 were placed in four containers, one sample was stored at room temperature, and the remaining three samples were stored at 100°C, 120°C, and 150°C for 1 hour, respectively. After heating, the state of the solution was observed with the naked eye. The results are shown in Figure 6. Figure 6 is a photograph showing the results of evaluating the thermal stability of the compound according to Example 1 and Comparative Example 1.

Referring to Figure 6, it can be seen that each of the compounds of Example 1 and Comparative Example 1 exists as a transparent and colorless liquid at room temperature. However, after heating at 150°C for 1 hour, it can be seen that the compound of Example 1 exists as a transparent colorless liquid, while the compound of Comparative Example 1 turns light yellow. From this, it can be confirmed that the compound of Example 1 is thermally stable compared to the compound of Comparative Example 1.

[Experimental Example 4]

The composition and surface roughness of tin oxide thin films formed using each of the compounds of Example 1 and Comparative Example 1 as precursors were analyzed. The composition of the thin film was analyzed using X-ray Photoelectron Spectroscopy (XPS), and the surface roughness was analyzed using Atomic Force Microscope (AFM). The results are shown in Table 1 below.

Stage temperature (℃) Showerhead temperature (℃) process pressure
(Torr) Argon flow rate (sccm) atomic concentration Surface roughness
(nm) Sn O C Sn/O Example 1 50 110 1.5 130 15.6 28.4 56 0.550 0.514 2 130 15.6 28.8 55.63 0.540 0.553 1.5 50 15.3 26.1 58.7 0.580 0.586 1.5 200 15.3 26.8 57.9 0.570 0.568 Comparative Example 1 50 110 1.5 130 14.99 27.78 57.23 0.540 0.681

Referring to Table 1, the tin oxide thin film of Example 1 has a Sn/O ratio of about 0.54 to 0.58, which is higher than that of Comparative Example 1, and the tin (Sn) content is higher than that of Comparative Example 1, while the carbon (C) concentration is higher than that of Comparative Example 1. It can be seen that it is relatively low compared to Comparative Example 1. Based on this, it can be seen that when the compound of Example 1 is used as a precursor, side reactions are reduced in the deposition process compared to when the compound of Comparative Example 1 is used as a precursor, and this results in the formation of a high-quality tin oxide thin film with a uniform composition. You can. In addition, the surface roughness of the tin oxide thin film of Example 1 was at the level of 0.514 nm to 0.586 nm, but in the case of Comparative Example 1, it could be confirmed that the roughness was high at 0.681 nm. From this, it can be seen that the tin oxide thin film of Example 1 has superior film quality compared to the tin oxide thin film of Comparative Example 1.

[Experimental Example 5]

A heating test was conducted to determine the thermal stability of the tin oxide thin films prepared according to Example 1 and Comparative Example 1. Specifically, several tin oxide thin films deposited on a silicon substrate were prepared, placed in chambers heated to temperatures of 100°C, 150°C, and 200°C, and stored for 30 minutes. Afterwards, atomic concentration analysis was performed using X-ray photoelectron spectroscopy on samples stored at each temperature. The results are shown in Figures 7 and 8. FIG. 7 is a graph showing the results of X-ray photoelectron spectroscopy analysis of the tin oxide thin film according to Example 1, and FIG. 8 is a graph showing the results of X-ray photoelectron spectroscopy analysis of the tin oxide thin film according to Comparative Example 1. At this time, the results of X-ray photoelectron spectroscopy analysis for the sample without heat treatment are also shown.

Referring to FIG. 7, it can be seen that the tin oxide thin film according to Example 1 does not have a significant difference in atomic concentration from the tin oxide thin film that has not been heat treated even if the heat treatment temperature is increased from 100°C to 200°C. However, at temperatures above 150°C, a slight decrease in carbon concentration was observed due to volatilization of carbon-containing ligands in the thin film. Referring to FIG. 8, it can be seen that the carbon concentration of the tin oxide thin film of Comparative Example 1 rapidly decreases (more than 5%) at a temperature of 150°C or higher. From this, it can be seen that the tin oxide thin film deposited using the organic tin compound of Example 1 as a precursor has excellent thermal stability compared to the tin oxide thin film using the compound of Comparative Example 1.

To summarize the above experimental examples, the organic tin compound according to an embodiment of the present invention has the advantage of excellent structural and thermal stability and high reactivity. Accordingly, the organic tin compound according to an embodiment of the present invention can be advantageously used as a precursor for forming a tin-containing thin film by chemical vapor deposition. When a deposition process is performed using the organic tin compound as a precursor according to an embodiment of the present invention, a high-quality tin-containing thin film with uniform film thickness and film quality and low residue content can be obtained.

The organic tin compound, its production method, and the method of forming a tin-containing thin film according to various embodiments of the present invention can be described as follows.

An organic tin compound according to an embodiment of the present invention is represented by the following formula (1).

[Formula 1]

In Formula 1, R ₁ to R ₄ are each independently a linear alkyl group having 1 to 6 carbon atoms or a branched alkyl group having 3 to 6 carbon atoms.

According to another feature of the present invention, in Formula 1, R ₁ to R ₄ may each independently be a branched alkyl group having 3 to 6 carbon atoms.

According to another feature of the present invention, in Formula 1, R ₂ , R ₃ and R ₄ may be the same as each other.

According to another feature of the present invention, the organic tin compound may be represented by the following formula (2).

[Formula 2]

According to another feature of the present invention, the organic tin compound may be liquid at room temperature.

The method for producing an organic tin compound according to an embodiment of the present invention is to react a tin (IV) chloride (SnCl ₄ ) compound with an alkyl magnesium halide compound represented by Formula A to produce a monoalkyl tin trihalide compound represented by Formula B. It includes a first step of preparing a compound represented by the following formula (1) by reacting a monoalkyl tin trihalide compound with an alcohol in the presence of a base catalyst.

[Formula A] R ₁ MgX

[Formula B] Sn(R ₁ )Cl ₃

In formulas A and B, R ₁ is a linear alkyl group having 1 to 6 carbon atoms or a branched alkyl group having 3 to 6 carbon atoms, and in formula A, X is Cl or Br.

[Formula 1]

In Formula 1, R ₁ to R ₄ are each independently a linear alkyl group having 1 to 6 carbon atoms or a branched alkyl group having 3 to 6 carbon atoms, and R ₂ to R ₄ are an alkyl group derived from the second stage alcohol.

According to another feature of the present invention, the base catalyst may be at least one selected from triethylamine and diisopropylethylamine.

A method of forming a tin-containing thin film according to an embodiment of the present invention includes depositing a thin film on a substrate using the organic tin compound as a precursor.

According to another feature of the present invention, the step of depositing a thin film may be performed using a Metal Organic Chemical Vapor Deposition (MOCVD) process or an Atomic Layer Deposition (ALD) process.

According to another feature of the present invention, the step of depositing the thin film may be performed in a temperature range of 100°C to 1000°C.

According to another feature of the present invention, the step of depositing a thin film is a bubbling method, a vapor phase mass flow controller (MFC) method, a direct gas injection (DGI) method, or a direct gas injection method. It may include moving the organic tin compound onto the substrate through one method selected from a direct liquid injection (DLI) method and an organic solution supply method that dissolves the organic tin compound in an organic solvent and moves it. .

According to another feature of the present invention, the organic tin compound moves onto the substrate by bubbling or direct gas injection with a carrier gas, and the carrier gas is argon (Ar), nitrogen (N ₂ ), or helium (He). ) and hydrogen (H ₂ ).

According to another feature of the present invention, in the step of depositing a thin film, water vapor (H ₂ O), oxygen (O ₂ ), oxygen plasma, ozone (O ₃ ), hydrogen peroxide (H ₂ O ₂ ), and ammonia (NH ₃ ), hydrazine (N ₂ H ₄ ), nitrous oxide (N ₂ O), and nitrogen (N ₂ ) may be further included.

Although the present invention has been described in detail through examples above, the present invention is not necessarily limited to these examples, and may be implemented in various modifications without departing from the technical spirit of the present invention. Accordingly, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention but are for illustrative purposes, and the scope of the technical idea of the present invention is not limited by these embodiments. Therefore, the embodiments described above should be understood in all respects as illustrative and not restrictive. The scope of protection of the present invention should be interpreted in accordance with the claims below, and all technical ideas within the equivalent scope should be construed as being included in the scope of rights of the present invention.

Claims (13)

An organic tin compound represented by the following formula (1).
[Formula 1]

In Formula 1,
R ₁ to R ₄ are each independently a linear alkyl group having 1 to 6 carbon atoms or a branched alkyl group having 3 to 6 carbon atoms. According to paragraph 1,
In Formula 1, R ₁ to R ₄ are each independently a branched alkyl group having 3 to 6 carbon atoms. According to paragraph 1,
In Formula 1, R ₂ , R ₃ and R ₄ are the same as each other, an organic tin compound. According to paragraph 1,
An organic tin compound represented by the following formula (2).
[Formula 2]
According to paragraph 1,
The organic tin compound is a liquid at room temperature. A first step of preparing a monoalkyl tin trihalide compound represented by Formula B by reacting a tin(IV) chloride (SnCl ₄ ) compound with an alkyl magnesium halide compound represented by Formula A; and
A method for producing an organic tin compound, comprising a second step of reacting the monoalkyl tin trihalide compound with an alcohol under a base catalyst to prepare a compound represented by the following formula (1).
[Formula A] R ₁ MgX
[Formula B] Sn(R ₁ )Cl ₃
In Formulas A and B, R ₁ is a linear alkyl group having 1 to 6 carbon atoms or a branched alkyl group having 3 to 6 carbon atoms, and in Formula A,
[Formula 1]

In Formula 1, R ₁ to R ₄ are each independently a linear alkyl group having 1 to 6 carbon atoms or a branched alkyl group having 3 to 6 carbon atoms, and R ₂ to R ₄ are an alkyl group derived from the second stage alcohol. According to clause 6,
A method for producing an organic tin compound, wherein the base catalyst is at least one selected from triethylamine and diisopropylethylamine. A method of forming a tin-containing thin film, comprising the step of depositing a thin film on a substrate using the organic tin compound of any one of claims 1 to 5 as a precursor. According to clause 8,
A method of forming a tin-containing thin film, wherein the step of depositing the thin film is performed by a Metal Organic Chemical Vapor Deposition (MOCVD) process or an Atomic Layer Deposition (ALD) process. According to clause 8,
A method of forming a tin-containing thin film, wherein the step of depositing the thin film is performed in a temperature range of 100°C to 1000°C. According to clause 8,
The step of depositing the thin film is a bubbling method, a vapor phase mass flow controller (MFC) method, a direct gas injection (DGI) method, and a direct liquid injection (DLI) method. ) Method of forming a tin-containing thin film, comprising the step of moving the organotin compound onto the substrate through a method selected from the group consisting of a method and an organic solution supply method in which the organotin compound is dissolved in an organic solvent and moved. According to clause 8,
The organic tin compound moves onto the substrate by the bubbling method or the direct gas injection method together with the carrier gas,
The carrier gas includes one or more selected from argon (Ar), nitrogen (N ₂ ), helium (He), and hydrogen (H ₂ ). According to clause 8,
In the step of depositing the thin film, water vapor (H ₂ O), oxygen (O ₂ ), oxygen plasma, ozone (O ₃ ), hydrogen peroxide (H ₂ O ₂ ), ammonia (NH ₃ ), and hydrazine (N ₂ H ₄ ), nitrous oxide (N ₂ O), and nitrogen (N ₂ ), further comprising the step of supplying one or more reaction gases selected from the group consisting of nitrous oxide (N 2 O) and nitrogen (N 2 ).

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