WO2024049037A1 - Novel amidinate ligand, and thin film formation precursor comprising ligand - Google Patents

Abstract

The present invention relates to an amidinate ligand represented by chemical formula 1, and a thin film formation precursor comprising the ligand, and, to: a novel amidinate ligand capable of exhibiting chemical properties such as high structural stability, low viscosity, high volatility, high heat resistance and a room-temperature liquid form of a precursor; and a thin film formation precursor comprising the ligand.

Description

Novel amidinate ligand, precursor for thin film formation containing the ligand

The present invention relates to a novel amidinate ligand and a precursor for forming a thin film containing the ligand. More specifically, by including a novel amidinate ligand, the present invention has low viscosity, high heat resistance, high volatility, and is liquid at room temperature. It relates to an amidinate ligand that constitutes a precursor and thereby allows the formation of a high-quality thin film, and a precursor for forming a thin film containing the ligand.

Due to the improvement in integration through the miniaturization of the line width of semiconductor devices, the space allowed for the implementation of the capacitor structure is limited in terms of the line width, and there are limitations in the manufacturing method of the semiconductor device for implementing the capacitor structure using the existing method. In particular, as high dielectric thin films are applied, a problem arises in which leakage current due to the band gap deteriorates significantly. As one of the ways to solve this problem, technology for forming high-quality thin films is required, and for this purpose, it is necessary to optimize the precursor used to form thin films.

The precursor for thin film formation consists of a central metal atom and a ligand. Since chemical properties such as viscosity, heat resistance, and volatility vary depending on the structure of the ligand, precursors combining various types of ligands are being developed with this in mind.

For example, in known technologies such as Korean Patent Publication No. 10-1660052, Korean Patent Publication No. 10-2019-0109142, and 10-2021-0084297, cyclopentadienyl and cyclopentadienyl are used as precursors containing yttrium or lanthanide metal. A chemical structure in which amidinate is bound to a ligand is presented. The precursor to which this ligand is bound is reported to be suitable for the thin film formation process because it can improve the disadvantages of existing yttrium or lanthanide metal precursors with low vapor pressure and high viscosity.

However, these conventional precursors may still cause various problems in the process for forming a semiconductor thin film due to their high viscosity. Therefore, it is necessary to develop a precursor that exhibits the chemical properties of the precursor required in the semiconductor thin film formation process (liquid phase, high volatility, high heat resistance, etc.) while improving the viscosity properties. In particular, referring to the results of known technologies, it is expected that a chemical structure containing amidinate as a ligand can obtain the chemical properties of the precursor required in the thin film formation process.

The present invention was conceived in consideration of the above-described prior technologies, and its purpose is to provide a novel amidinate ligand that can be applied to a precursor for thin film formation.

In addition, the purpose is to provide a precursor for forming a thin film that includes the above-mentioned ligand and exhibits chemical properties of low viscosity, high heat resistance, and high volatility.

The amidinate ligand of the present invention to achieve the above object is used as a ligand to form a precursor for forming a thin film, and is characterized by being a compound represented by the following formula (1).

[Formula 1]

In Formula 1, R ₁ and R ₃ are each independently a C ₁ -C ₅ straight-chain, branched, or cyclic alkyl group or alkenyl group, and R ₂ is a hydrogen atom or a C ₁ -C ₄ straight-chain, branched alkyl group. It is a linear or cyclic alkyl group or an alkenyl group.

Additionally, in Formula 1, R ₂ may be a C ₂ -C ₄ straight-chain, branched, or cyclic alkyl group or alkenyl group.

In addition, in Formula 1, R ₁ and R ₃ are each independently a C ₂ -C ₅ straight-chain, branched, or cyclic alkyl group or alkenyl group, and R ₂ is a C ₂ -C ₄ straight-chain, branched alkyl group. It may be a linear or cyclic alkyl group or an alkenyl group.

Additionally, in Formula 1, R ₁ and R ₃ may be methyl groups.

Additionally, in Formula 1, R ₂ may be an isopropyl group.

Additionally, in Formula 1, R ₁ and R ₃ may each independently be a C ₁ -C ₅ linear alkyl group or an alkenyl group.

Additionally, in Formula 1, R ₁ and R ₃ are each independently a straight-chain alkyl group or an alkenyl group, and R ₂ may be a C ₁ -C ₄ straight-chain alkyl group or an alkenyl group.

Additionally, in Formula 1, R ₁ and R ₃ are both the same and may be an alkyl group or an alkenyl group.

Additionally, in Formula 1, R ₁ to R ₃ are all the same and may be an alkyl group or an alkenyl group.

Additionally, the amidinate ligand may be any one or more selected from the chemical structures below.

The precursor for forming a thin film of the present invention includes the amidinate ligand, and the central metal atom may be any one of a Group 2 to 6 element, a Group 13 element, a Group 15 element, a transition metal, and a rare earth element.

Additionally, the central metal atom may be any one of yttrium (Y), scandium (Sc), or a lanthanide element.

Additionally, the precursor for forming the thin film may be a compound represented by the following formula (2).

[Formula 2]

(L) _n -M-(AMD) _m

In Formula 2, AMD has the same structure as Formula 1, M is the central metal atom and is any one of Groups 2 to 6 elements, Group 13 elements, Group 15 elements, transition metals, and rare earth elements, and L is the same as AMD. or a different ligand, if different from the AMD, a substituted or unsubstituted cyclopentadienyl group, amine, alcohol, alkyl, aryl, amino amine, alkoxy amine, amino alcohol, alkoxy alcohol, imido, diamine, dial alcohol, It may be any one of fomidinate, guanidinate, beta-diketonate, ketoiminate, amide, and halide. Additionally, n may be 0 to 5, and m may be 1 to 6.

When applied to a precursor, the novel amidinate ligand according to the present invention can exhibit the chemical properties of the precursor compound such as high structural stability, low viscosity, high volatility, high heat resistance, and liquid form at room temperature.

Therefore, the precursor for forming a thin film containing the amidinate ligand exhibits physical properties suitable for use in the thin film forming process and can form a high-quality thin film without thermal decomposition during the process or residual issues in the pipe due to high viscosity, and the thin film forming method A semiconductor device including a thin film manufactured by can be provided.

Figure 1 shows the results of ¹ H-NMR analysis of diethyl-ethylamidinate ligand.

Figure 2 shows the results of TGA analysis of diethyl-ethylamidinate ligand.

Figure 3 shows the results of ¹ H-NMR analysis of diethyl-normal propylamidinate ligand.

Figure 4 shows the TGA analysis results of diethyl-normal propylamidinate ligand.

Figure 5 shows the results of ¹ H-NMR analysis of dinormal propyl-ethylamidinate ligand.

Figure 6 shows the TGA analysis results of dinormal propyl-ethylamidinate ligand.

Figure 7 shows the ¹ H-NMR analysis results of bis(ethylcyclopentadienyl)(diethyl-ethylamidinato)yttrium.

Figure 8 shows the TGA analysis results of bis(ethylcyclopentadienyl)(diethyl-ethylamidinato)yttrium.

Figure 9 shows the DSC analysis results of bis(ethylcyclopentadienyl)(diethyl-ethylamidinato)yttrium.

Figure 10 shows the ¹ H-NMR analysis results of bis(ethylcyclopentadienyl)(diethyl-normal propylamidinato)yttrium.

Figure 11 shows the TGA analysis results of bis(ethylcyclopentadienyl)(diethyl-normalpropylamidinato)yttrium.

Figure 12 shows the ¹ H-NMR analysis results of tris(diethyl-normal propylamidinato)yttrium.

Figure 13 shows the TGA analysis results of tris(diethyl-normal propylamidinato)yttrium.

Hereinafter, the present invention will be described in more detail. Terms or words used in this specification and claims should not be construed as limited to their common or dictionary meanings, and the inventor may appropriately define the concept of terms in order to explain his or her invention in the best way. It must be interpreted with meaning and concept consistent with the technical idea of the present invention based on the principle that it is.

The amidinate ligand according to the present invention is characterized in that it is a compound represented by the following formula (1).

[Formula 1]

In Formula 1,

R ₁ and R ₃ are each independently a C ₁ -C ₅ straight-chain, branched, or cyclic alkyl group or alkenyl group, and R ₂ is a hydrogen atom or a C ₁ -C ₄ straight-chain, branched, or cyclic alkyl group. Or it is an alkenyl group.

The compound is used as a ligand for a precursor compound for forming a thin film. In particular, in the amidinate ligand, R ₁ and R ₃ may be the same or different, and may be of various forms depending on the desired effect of the precursor containing the ligand. It can be composed of:

Additionally, in Formula 1, R ₂ may be a hydrogen atom, a C ₁ -C ₄ straight-chain, branched, or cyclic alkyl group, or an alkenyl group. Non-limiting examples include R ₂ being an ethyl group, a propyl group, or a butyl group. It may contain an n-alkyl group such as a group.

The precursor containing the amidinate ligand represented by Formula 1 has low viscosity, high thermal stability and volatility, and can be in a liquid form at room temperature, so that the chemical properties of the desired precursor can be obtained through the synthesis of the precursor containing the ligand. It turned out that it was possible. That is, because it exhibits overall improved physical properties compared to various precursor compounds containing amidinate ligands in the prior art, improved effects can be obtained as a precursor and in the thin film formation process using the precursor.

The amidinate ligand represented by Formula 1 may be formed by combining various functional groups.

In one embodiment, R ₂ may be a straight-chain, branched, or cyclic alkyl group or alkenyl group of C ₂ -C ₄ , and when R ₂ is provided as C ₂ or more, compared to the case where R 2 is H or C ₁ As a result, structural asymmetry can be increased while minimizing intramolecular structural steric hindrance, thereby reducing mutual interference between molecules. Therefore, the precursor containing the ligand is not only easy to form in liquid form, but also can obtain low viscosity characteristics.

Meanwhile, R ₁ and R ₃ are each independently a C ₂ -C ₅ straight-chain, branched, or cyclic alkyl group or alkenyl group, and R ₂ is a C ₂ -C ₄ straight-chain, branched, or cyclic alkyl group. It may be an alkyl group or an alkenyl group.

In another embodiment, R ₁ and R ₃ may be a methyl group, and R ₂ may be an isopropyl group.

Additionally, R ₁ and R ₃ may each independently be a C ₁ -C ₅ linear alkyl group or an alkenyl group.

Straight-chain alkyl or alkenyl groups can improve volatility and vapor pressure by reducing the molecular weight by minimizing the structure of the ligand compared to branched or cyclic groups. Therefore, in the ligand according to an embodiment of the present invention, each of R ₁ and R ₃ may be composed of a straight-chain alkyl group or an alkenyl group. In this case, the vapor pressure of the precursor for forming a thin film containing the ligand is improved, so the precursor This can lead to benefits such as process ease during the thin film formation process using .

In addition to the effect of improving vapor pressure, the ligand, in which each of R ₁ and R ₃ is composed of a straight-chain alkyl group, has a high structural freedom of the ligand, so it can provide an effect of improving the freedom of the precursor to which the ligand is applied. This effect is achieved by the interaction between the precursors. By minimizing indirection, it has the effect of creating liquefaction and low viscosity characteristics of the precursor.

Therefore, in the amidinate ligand according to one embodiment, in Formula 1, R ₁ and R ₃ may be composed of a straight-chain alkyl group or an alkenyl group. In this case, the vapor pressure of the precursor containing the ligand may be improved. By improving the degree of freedom, it is not only easy to form it into a liquid form, but also can obtain low viscosity characteristics.

Meanwhile, R ₁ and R ₃ are each independently a C ₁ -C ₅ linear alkyl group or alkenyl group, and R ₂ may be a C ₁ -C ₄ linear alkyl group or alkenyl group.

In addition, R ₁ and R ₃ are both the same, and may be a C ₁ -C ₅ straight-chain, branched, or cyclic alkyl group or alkenyl group.

In addition, R ₁ to R ₃ are all the same, and may be a C ₁ -C ₄ straight-chain, branched, or cyclic alkyl group or alkenyl group.

Exemplary structures of such amidinate ligands include one or more structures selected from the following chemical structures.

Meanwhile, the present invention provides a precursor for forming a thin film containing the amidinate ligand. The precursor for forming the thin film may have a central metal atom selected from the group 2 to 6 elements, group 13 elements, group 15 elements, transition metals, and rare earth elements.

As a non-limiting example, the central metal atom may be any of yttrium (Y), scandium (Sc), or a lanthanide element.

In one embodiment, the precursor for forming a thin film containing the amidinate ligand may be a compound represented by Formula 2 below.

[Formula 2]

(L) _n -M-(AMD) _m

In Formula 2, AMD has the same structure as Formula 1, M is the central metal atom and is any one of Groups 2 to 6 elements, Group 13 elements, Group 15 elements, transition metals, and rare earth elements, and L is the same as AMD. or a different ligand, if different from the AMD, a substituted or unsubstituted cyclopentadienyl group, amine, alcohol, alkyl, aryl, amino amine, alkoxy amine, amino alcohol, alkoxy alcohol, imido, diamine, dial alcohol, It may be any one of fomidinate, guanidinate, beta-diketonate, ketoiminate, amide, and halide. Additionally, n may be 0 to 5, and m may be 1 to 6.

As a non-limiting example, the precursor for forming a thin film that can be represented by Formula 2 may be any one of the compounds represented by the following chemical structures.

As described above, the precursor for thin film formation according to the present invention contains the novel amidinate ligand according to the present invention and can be provided in low viscosity, high heat resistance, high volatility, and liquid form, thereby forming a high-quality thin film. can make it possible.

In addition, the precursor for forming a thin film of the present invention may additionally include a solvent for dissolving or diluting the precursor compound in consideration of the conditions and efficiency of the thin film forming process. The solvent may be any one of C ₁ -C ₁₆ saturated or unsaturated hydrocarbons, ketones, ethers, glymes, esters, tetrahydrofuran, tertiary amines, or mixtures thereof. Examples of the C ₁ -C ₁₆ saturated or unsaturated hydrocarbon include pentane, cyclohexane, ethylcyclohexane, heptane, octane, toluene, etc., and tertiary amines include dimethylethylamine and triethylamine. .

In particular, depending on the chemical structure, the precursor compound for forming a thin film may be in a solid state at room temperature. In this case, the compound can be dissolved by including the solvent. That is, when the solvent is included, it is contained in a solvent and amount capable of dissolving the precursor compound, and is preferably contained in 1 to 99% by weight based on the total weight of the precursor for forming the thin film.

Since the precursor containing or not containing the solvent can be vaporized, it can be supplied into the chamber in the form of precursor gas. Therefore, depending on the type of precursor compound, if it exists in a liquid state at room temperature and can be easily vaporized, the thin film formation process can be performed without a separate solvent.

In this case, the thin film formation process includes a spin-on dielectric (SOD) process, a low temperature plasma (LTP) process, a chemical vapor deposition (CVD), and a plasma enhanced chemical vapor deposition. Deposition, PECVD), High Density Plasma -Chemical Vapor Deposition (HDPCVD) process, Atomic Layer Deposition (ALD) process, or Plasma-Enhanced Atomic Layer Deposition (PEALD) It can be performed by any one of the processes.

For example, when applying the HDP-CVD process, the high vacuum and high Because it can be carried out at high power, it is possible to form a thin film that is structurally dense and has excellent mechanical properties.

To this end, the thin film forming method according to the present invention includes a process of forming a thin film on a substrate using the thin film forming precursor.

Specifically, the process of forming a thin film on the substrate may include a process of forming a precursor thin film by depositing the thin film forming precursor on the surface of the substrate and a process of reacting the precursor thin film with a reactant.

Additionally, in order to deposit the precursor, a process of vaporizing the thin film forming precursor and transferring it into the chamber may be included.

In addition, the process of forming a thin film on the substrate may include forming a thin film of a metal, oxide, nitride, oxynitride, etc. by supplying the thin film forming precursor to the substrate and applying plasma in the presence of a reactant. .

The process of forming the thin film can be performed under chamber pressure conditions of 0.1 to 1000 mTorr. In addition, the source power for forming plasma in the chamber is 500 to 9,000 W, and the bias power is 0 to 5,000 W. Additionally, the bias power may not be applied depending on the case.

Additionally, the process of forming a thin film on a substrate is preferably performed at a temperature range of 150 to 500°C.

In addition, when supplying the thin film forming precursor, a second metal precursor may be introduced as needed to further improve the electrical properties, that is, the capacitance or leakage current value, of the final formed metal film. The second metal precursor is magnesium (Mg), strontium (Sr), barium (Ba), lanthanide (Ln), titanium (Ti), zirconium (Zr), hafnium (Hf), niobium (Nb), and tantalum (Ta). ), a metal precursor containing one or more metals (M") selected from aluminum (Al), indium (In), silicon (Si), germanium (Ge), and tin (Sn) atoms may be optionally further supplied. The second metal precursor may be an alkylamide-based compound or an alkoxy-based compound containing the metal. For example, when the metal is Si, the second metal precursor may be SiH(N(CH ₃ ) ₂ ) ₃ , SiH ₂ ( N(C ₂ H ₅ ) ₂ ) ₂ , SiH ₂ (NHtBu) ₂ , SiH ₃ (N(iPr) ₂ ), Si(OC ₄ H ₉ ) ₄ , Si(OC ₂ H ₅ ) ₄ , Si(OCH ₃ ) ₄ , Si(OC(CH ₃ ) ₃ ) ₄ , etc. may be used.

The supply of the second metal precursor may be carried out in the same manner as the supply method of the thin film formation precursor, and the second metal precursor may be supplied together with the precursor onto the thin film formation substrate, or the supply of the precursor may be completed. It may then be supplied sequentially.

The precursor and optionally the second metal precursor as described above are preferably maintained at a temperature of 50 to 250° C. before being supplied into the reaction chamber for contact with the substrate for forming the thin film, more preferably 100 to 200° C. It is good to maintain .

In addition, after supplying the precursor and prior to supplying the reactant, it assists the movement of the precursor and optionally the second metal precursor onto the substrate, ensures an appropriate pressure for deposition within the reactor, and also removes impurities present in the chamber. In order to discharge it to the outside, a process of purging an inert gas such as argon (Ar), nitrogen (N ₂ ), or helium (He) may be performed in the reactor. At this time, it is preferable that the inert gas is spread so that the pressure inside the reactor is 1 to 5 Torr.

In addition, the reactants include nitrogen (N ₂ ), ammonia (NH ₃ ), hydrazine (N ₂ H ₄ ), nitrous oxide (N ₂ O), oxygen (O ₂ ), water vapor (H ₂ O), and ozone. (O ₃ ), hydrogen peroxide (H ₂ O ₂ ), silane, hydrogen (H), diborane (B ₂ H ₆ ), or a mixture thereof can be used. When carried out in the presence of oxidizing gases such as water vapor, oxygen, ozone, etc., a magnesium oxide thin film may be formed, and when carried out in the presence of reducing gases such as hydrogen, ammonia, hydrazine, silane, etc., a thin film of metal alone or metal nitride may be formed. You can. Additionally, a metal oxynitride thin film can be formed by mixing reactants.

Additionally, in addition to plasma treatment, a heat treatment or light irradiation treatment process may be performed to provide heat energy for deposition of a thin film forming precursor, and may be performed according to a conventional method. Preferably, in order to produce a thin film having the desired physical state and composition at a sufficient growth rate, the treatment process is preferably performed so that the temperature of the substrate in the reactor is 100 to 1,000°C, preferably 250 to 400°C. .

In addition, during the treatment process, as described above, argon is used in the reactor to help the reactant move onto the substrate, to maintain an appropriate pressure for deposition within the reactor, and to release impurities or by-products present in the reactor to the outside. A process of purging an inert gas such as (Ar), nitrogen (N ₂ ), or helium (He) may be performed.

As described above, the process of adding the precursor for forming a thin film, adding the reactant, and adding the inert gas is one cycle. A thin film can be formed by repeating the process one or more cycles.

Additionally, by applying the thin film forming process, various semiconductor devices including thin films can be manufactured.

Hereinafter, the effects of the present invention will be explained through examples.

[Example 1] Synthesis of diethyl-ethylamidinate (Et ₂ Et-AMD)

In a 500 mL Schlenk flask, 132.1 g (0.75 mol) of triethyl ortho-propionate and 74.3 g (1.65 mol) of ethylamine were added, then cooled to -30°C and stirred. At the same temperature, 99.0 g (1.65 mol) of acetic acid was slowly added dropwise and refluxed at 170°C. After 18 hours, the solvent was removed under reduced pressure and extracted with 5N aqueous sodium hydroxide (NaOH) solution and diethyl ether. After drying with magnesium sulfate, it was filtered, and the solvent was removed under reduced pressure. Distilled under reduced pressure to obtain 46.1 g (48%) of a colorless liquid compound. The NMR analysis results are shown in Figure 1.

¹ H NMR (CDCl ₃ , 25°C): 1.13 (m, 9H), 2.20 (q, 2H), 3.17 (m, 4H).

Purification conditions: 75~78℃ @ 2.4 torr

The light yellow liquid was 0% during TGA analysis, which was measured at a temperature rise rate of 10°C/min in an atmosphere flowing nitrogen at 200 mL/min, leaving little residual mass. These results were confirmed by TGA analysis results (FIG. 2) showing the percentage of weight loss according to temperature change.

[Example 2] Synthesis of diethyl-normal propylamidinate (Et ₂ nPr-AMD)

Add 122.5g (0.64mol) of 1,1,1-Triethoxybutane and 58.0g (1.29mol) of ethylamine in a 500ml Schlenk flask and then -30℃. It was cooled and stirred. At the same temperature, 77.3 g (1.29 mol) of acetic acid was slowly added dropwise and refluxed at 170°C. After 18 hours, the solvent was removed under reduced pressure and extracted with 5N aqueous sodium hydroxide (NaOH) solution and diethyl ether. After drying with magnesium sulfate, the mixture was filtered and the solvent was removed under reduced pressure. By distillation under reduced pressure, 36.6 g (40%) of a colorless liquid compound was obtained. The NMR analysis results are shown in Figure 3.

¹ H NMR (CDCl ₃ , 25°C): 0.98(t, 3H), 1.15(m, 6H), 1.59(m, 2H), 2.15(m, 2H), 3.22(m, 4H).

Purification conditions: 82~87℃ @ 0.5 torr

The light yellow liquid was 0% during TGA analysis, which was measured at a temperature rise rate of 10°C/min in an atmosphere flowing nitrogen at 200 mL/min, leaving little residual mass. These results were confirmed by TGA analysis results (FIG. 4) showing the percentage of weight loss according to temperature change.

[Example 3] Synthesis of dinormal propyl-ethylamidinate (nPr ₂ Et-AMD)

In a 500 mL Schlenk flask, add 132.1 g (0.75 mol) of triethyl ortho-propionate and 97.5 g (1.65 mol) of n-Propylamine, then cool to -30°C and stir. did. At the same temperature, 49.5 g (0.83 mol) of acetic acid was slowly added dropwise and refluxed at 170°C. After 18 hours, the solvent was removed under reduced pressure and extracted with 5N aqueous sodium hydroxide (NaOH) solution and diethyl ether. After drying with magnesium sulfate, the mixture was filtered and the solvent was removed under reduced pressure. Distilled under reduced pressure to obtain 48.0 g (41%) of a colorless liquid compound. The NMR analysis results are shown in Figure 5.

¹ H NMR (CDCl ₃ , 25°C): 0.70(t, 6H), 0.89(t, 3H), 1.31(m, 4H), 1.97(m, 2H), 2.90(m, 4H).

Purification conditions: 80~90℃ @ 0.5 torr

The light yellow liquid was 0% during TGA analysis, which was measured at a temperature rise rate of 10°C/min in an atmosphere flowing nitrogen at 200 mL/min, leaving little residual mass. These results were confirmed by TGA analysis results (FIG. 6) showing the percentage of weight loss according to temperature change.

[Example 4] Synthesis of bis(ethylcyclopentadienyl)(diethyl-ethyl adinato)yttrium [(EtCp) ₂ Y(Et ₂ Et-AMD)]

Add 32.83 g (0.256 mol) of diethyl-ethylamidinate to 300 ml of THF, cool to -78°C, and slowly add 102.4 ml (0.256 mol) of n-BuLi hexane solution (2.5 M) dropwise to form Li-( Et ₂ Et-AMD) was prepared. The solution was stirred at -78°C for 30 minutes, then warmed to room temperature, and stirred for an additional 2 hours at room temperature. The prepared Li-(Et ₂ Et-AMD) solution was slowly added dropwise to a flask containing (EtCp) ₂ YCl at room temperature and stirred at room temperature for 12 hours. The mixture was evaporated under vacuum, dissolved in 250 ml of pentane, and then filtered to evaporate the solvent and volatile substances under vacuum. The resulting red liquid was converted into a light yellow liquid at 165°C and 40 mTorr. The yield was 60.1g (58.3%). The NMR analysis results are shown in Figure 7.

¹ H NMR (C ₆ D ₆ , 25°C): 0.85(t, 3H), 0.98(t, 6H), 1.20(t, 6H), 1.97(q, 2H), 2.48(q, 4H), 2.97( q, 4H), 6.0(dt, 8H).

The light yellow liquid was 0% during TGA analysis, which was measured at a temperature rise rate of 10°C/min in an atmosphere flowing nitrogen at 200 mL/min, leaving little residual mass. These results were confirmed by TGA analysis results (FIG. 8) showing the percentage of weight loss according to temperature change.

The light yellow liquid sample was placed in an airtight container for DSC and maintained at 40°C for 10 minutes, and then a decomposition peak was observed at 377°C during DSC analysis measured at a temperature rise rate of 10°C/min. These results were confirmed by DSC analysis results (FIG. 9) showing the change in thermal energy according to temperature change.

The light yellow liquid sample was placed in a rotary viscosity measuring container and the viscosity was measured using a low viscosity spindle at 25°C. While measuring the viscosity at 12 RPM, a viscosity of 30 cP was measured.

[Example 5] Synthesis of bis(ethylcyclopentadienyl)(diethyl-normalpropylamidinato)yttrium[(EtCp) ₂ Y(Et ₂ nPr-AMD)]

Add 36.43 g (0.256 mol) of diethyl-normal propylamidinate to 300 ml of THF, cool to -78°C, and slowly add 102.4 ml (0.256 mol) of n-BuLi hexane solution (2.5 M) dropwise to form Li- (Et ₂ nPr-AMD) was prepared. The solution was stirred at -78°C for 30 minutes, then warmed to room temperature, and stirred for an additional 2 hours at room temperature. The prepared Li-(Et ₂ nPr-AMD) solution was slowly added dropwise to a flask containing Y(EtCp) ₂ Cl at room temperature and stirred at room temperature for 12 hours. The mixture was evaporated under vacuum, dissolved in 250 ml of pentane, and then filtered to evaporate the solvent and volatile substances under vacuum. The resulting red liquid was distilled at 185°C and 40 mTorr to obtain a light yellow liquid. The yield was 65.1g (61.0%). The NMR analysis results are shown in Figure 10.

¹ H NMR (C ₆ D ₆ , 25°C): 0.83(t, 3H), 0.99(t, 6H), 1.20(t, 6H), 1.36(q, 2H), 1.98(q, 2H), 2.50( q, 4H), 3.00(q, 4H), 6.0(dt, 8H).

The light yellow liquid was 0% during TGA analysis, which was measured at a temperature rise rate of 10°C/min in an atmosphere flowing nitrogen at 200 mL/min, leaving little residual mass. These results were confirmed by TGA analysis results (FIG. 11) showing the percentage of weight loss according to temperature change.

The light yellow liquid sample was placed in a rotary viscosity measuring container and the viscosity was measured using a low viscosity spindle at 25°C. While measuring the viscosity at 20 RPM, a viscosity of 28 cP was measured.

[Example 6] Synthesis of tris(diethyl-normalpropyl adinato)yttrium [Y(Et ₂ nPr-AMD) ₃ ]

Add 109.28 g (0.768 mol) of diethyl-normal propylamidinate to 300 ml of THF and cool to -78°C, then slowly add 307.3 ml (0.768 mol) of n-BuLi hexane solution (2.5 M) dropwise to form Li- (Et ₂ nPr-AMD) was prepared. The solution was stirred at -78°C for 30 minutes, then warmed to room temperature, and stirred for an additional 2 hours at room temperature. The prepared Li-(Et ₂ nPr-AMD) solution was slowly added dropwise to a flask containing YCl ₃ at -78°C and stirred at room temperature for 6 hours. The mixture was evaporated under vacuum, dissolved in 250 ml of pentane, and then filtered to evaporate the solvent and volatile substances under vacuum. The resulting red liquid was converted into a light yellow liquid at 184°C and 31 mTorr. The yield was 107.5g (81.9%). The NMR analysis results are shown in Figure 12.

¹ H NMR (C ₆ D ₆ , 25°C): 0.87(t, 9H), 1.32(t, 18H), 1.52(q, 6H), 2.21(q, 6H), 3.24(q, 12H)

The light yellow liquid left almost no residual mass at 0.75% during TGA analysis measured at a temperature rise rate of 10°C/min in an atmosphere flowing nitrogen at 200 mL/min. These results were confirmed by TGA analysis results (FIG. 13) showing the percentage of weight loss according to temperature change.

Through these experimental results, it was possible to obtain a liquid precursor with sufficient vapor pressure and thermal stability to be used as a semiconductor precursor in a structure using the new amidinate ligand according to the present invention. In particular, the viscosity characteristics of the precursor were greatly improved. It was confirmed that it was.

Although the present invention has been described with reference to preferred embodiments as described above, it is not limited to the above embodiments and may be modified in various ways by those skilled in the art without departing from the spirit of the invention. and can be changed. Such modifications and variations should be considered to fall within the scope of the present invention and the appended claims.

Claims (14)

1. An amidinate ligand, which is a compound represented by the following formula (1) and is used as a ligand to form a precursor for forming a thin film.

   [Formula 1]

   

   In Formula 1,

   R ₁ and R ₃ are each independently a C ₁ -C ₅ straight, branched or cyclic alkyl group or alkenyl group,

   R ₂ is a hydrogen atom or a C ₁ -C ₄ straight-chain, branched or cyclic alkyl group or alkenyl group.
2. In claim 1,

   In Formula 1, R ₂ is an amidinate ligand, characterized in that it is a C ₂ -C ₄ straight-chain, branched, or cyclic alkyl group or alkenyl group.
3. In claim 1,

   In Formula 1, R ₁ and R ₃ are each independently a C ₂ -C ₅ straight-chain, branched or cyclic alkyl group or alkenyl group, and R ₂ is a C ₂ -C ₄ straight-chain, branched or alkenyl group. An amidinate ligand characterized in that it is a cyclic alkyl group or an alkenyl group.
4. In claim 1,

   An amidinate ligand in Formula 1, wherein R ₁ and R ₃ are methyl groups.
5. In claim 1,

   In Formula 1, R ₂ is an amidinate ligand, characterized in that an isopropyl group.
6. In claim 1,

   In Formula 1, R ₁ and R ₃ are each independently a C ₁ -C ₅ straight-chain alkyl group or an alkenyl group.
7. In claim 1,

   In Formula 1, R ₁ and R ₃ are each independently a C ₁ -C ₅ straight-chain alkyl group or alkenyl group, and R ₂ is a C ₁ -C ₄ straight-chain alkyl group or alkenyl group. Mediated Ligand.
8. In claim 1,

   In Formula 1, R ₁ and R ₃ are the same, and are an amidinate ligand characterized in that they are a C ₁ -C ₅ straight-chain, branched, or cyclic alkyl group or alkenyl group.
9. In claim 1,

   In Formula 1, R ₁ to R ₃ are all the same, and are an amidinate ligand characterized in that they are a C ₁ -C ₄ straight-chain, branched, or cyclic alkyl group or alkenyl group.
10. In claim 1,

    The amidinate ligand is characterized in that one or more of the amidinate ligands are selected from the following chemical structures.

    
11. A precursor for forming a thin film, comprising the amidinate ligand according to any one of claims 1 to 10.
12. In claim 11,

    The precursor for forming a thin film is characterized in that the central metal atom is any one of a Group 2 to 6 element, a Group 13 element, a Group 15 element, a transition metal, and a rare earth element.
13. In claim 11,

    The precursor for forming a thin film is characterized in that the central metal atom is any one of yttrium (Y), scandium (Sc), or a lanthanide element.
14. In claim 11,

    A precursor for forming a thin film, characterized in that the precursor for forming a thin film is a compound represented by the following formula (2).

    [Formula 2]

    (L) _n -M-(AMD) _m

    In Formula 2, AMD has the same structure as Formula 1, M is the central metal atom and is any one of Groups 2 to 6 elements, Group 13 elements, Group 15 elements, transition metals, and rare earth elements, and L is the same as AMD. or a different ligand, if different from the AMD, a substituted or unsubstituted cyclopentadienyl group, amine, alcohol, alkyl, aryl, amino amine, alkoxy amine, amino alcohol, alkoxy alcohol, imido, diamine, dial alcohol, It is any one of fomidinate, guanidinate, beta-diketonate, ketoiminate, amide, and halide, n is 0 to 5, and m is 1 to 6.

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