Precursor for forming thin film, method for preparing the same, and method for preparing thin film containing the same

Abstract

The present invention relates to a precursor for thin film formation, a method for preparing the same, and a method for preparing a thin film including the same. Specifically, it relates to a precursor for thin film formation which is a liquid under the conditions of 20 °C and 1 bar, and includes 20 to 100% by weight of a coordination compound represented by Chemical Formula 1 and 0 to 80% by weight of an alkyl cyanide having 1 to 15 carbon atoms in the alkyl group, a method for preparing the same, and a method for preparing a thin film including the same. [Chemical Formula 1] MX n L m Y z Wherein, M is niobium (Nb), tungsten (W) or molybdenum (Mo); X is a halogen element; n is an integer from 1 to 6; L is an alkyl cyanide having 1 to 15 carbon atoms in the alkyl group, or a linear or cyclic saturated hydrocarbon having 3 to 15 carbon atoms and substituted with one or more nitrogen (N), oxygen (O), phosphorus (P) or sulfur (S); m is an integer from 1 to 3; the bound Y is an amine; z is an integer from 0 to 4; n + z is an integer from 3 to 6. According to the present invention, there is provided a precursor for thin film formation, a method for preparing the same, and a method for preparing a thin film including the same. The precursor for thin film formation is liquid at room temperature and has strong volatility, so the deposition rate is very fast. Moreover, when injected into a thin film deposition chamber, it is easy to handle, especially with excellent thermal stability, thus enabling the preparation of a thin film with high purity and excellent step coverage.

Description

Technical Field

[0001] The present invention relates to a thin film forming precursor, a preparation method thereof and a thin film preparation method containing the same, and specifically to a thin film forming precursor which is liquid at room temperature and has strong volatility, so the deposition speed is very fast, and when injected into a thin film deposition chamber, it is easy to handle, especially has excellent thermal stability, so that a thin film with high purity and excellent step coverage can be prepared, a preparation method thereof and a thin film preparation method containing the same. Background Art

[0002] Due to the use of chemical vapor deposition (CVD) and atomic layer deposition (ALD) as thin film deposition technologies, the size of semiconductor devices is further reduced and the integration of devices is also rapidly increasing.

[0003] However, in the above-mentioned chemical vapor deposition technology, all raw materials required to form a thin film are provided into the deposition chamber at the same time, so it is difficult to form a film with the desired composition ratio or physical properties, and the deposition is performed at a high temperature, which may cause degradation of the semiconductor device or reduction in capacitance.

[0004] In addition, in the above-mentioned atomic layer deposition technology, the raw materials required for forming a thin film are provided separately, so that a film with a desired composition ratio or physical properties can be formed, but the types of precursors used for thin film formation have many limitations. In particular, when metal chlorides are used as precursors for thin film formation, the dielectric film may be damaged, thereby causing degradation of the leakage current.

[0005] Niobium oxide (Nb2O5) thin films have a large dielectric constant and are not only a component of ferroelectric materials, but are also used as core materials for highly integrated non-volatile memories. Niobium nitride (NbN) thin films can also provide high work functions in fine patterns of semiconductor devices and are therefore widely used in the semiconductor field.

[0006] As a film-forming precursor for preparing the above-mentioned niobium thin film, a material in the form of Nb(OR)5 (R is an alkyl group) is generally used. However, this film-forming precursor has the disadvantages of high viscosity and low hydrolysis resistance, and because the alkoxide ligand is easily dissociated, it will cause a side reaction of generating oligomers or polymers when heated, resulting in reduced volatility, slow film formation speed, and changes in the composition of the film.

[0007] In addition, a thin film forming precursor in the form of Nb(NMe2)5 has also been developed. Although this material has relatively good sublimation properties, it has problems in that, as a solid, it has lower volatility than liquid thin film forming precursors, is prone to decomposition at temperatures above 150°C, has poor thermal stability, and has poor hydrolysis resistance.

[0008] Therefore, it is necessary to develop a thin film forming precursor that is liquid at room temperature, highly volatile, and has excellent thermal stability, and that can produce a niobium thin film that is excellent in both film formation speed and film physical properties.

[0009] Prior Art Literature

[0010] Patent Literature

[0011] Korean Patent Publication No. 2001-0038063 Summary of the invention

[0012] Technical issues

[0013] In order to solve the above-mentioned problems of the prior art, the purpose of the present invention is to provide a thin film forming precursor, a preparation method thereof and a thin film preparation method comprising the same. The thin film forming precursor is liquid at room temperature and has strong volatility, so the deposition speed is very fast, and when injected into the thin film deposition chamber, it is easy to handle, especially has excellent thermal stability, so that a thin film with high purity and excellent step coverage can be prepared.

[0014] The above-mentioned object and other objects of the present invention can all be achieved by the present invention described below.

[0015] Technical Solution

[0016] In order to achieve the above object, the present invention provides a thin film forming precursor which is liquid at 20°C and 1 bar and contains 20 to 100 wt % of a coordination compound represented by Chemical Formula 1 and 0 to 80 wt % of an alkyl cyanide having an alkyl group with 1 to 15 carbon atoms.

[0017] [Chemical formula 1]

[0018] MX n L m Y z

[0019] Wherein, M is niobium (Nb), tungsten (W) or molybdenum (Mo); X is a halogen element; n is an integer of 1 to 6; L is an alkyl cyanide having an alkyl group with 1 to 15 carbon atoms, or a linear or cyclic saturated hydrocarbon having 3 to 15 carbon atoms and substituted by one or more nitrogen (N), oxygen (O), phosphorus (O) or sulfur (S); m is an integer of 1 to 3; the bonded Y is an amine; z is an integer of 0 to 4; and n+z is an integer of 3 to 6.

[0020] In addition, the present invention provides a method for preparing a precursor for thin film formation, which comprises the following steps: reacting a compound represented by chemical formula 2 with an alkyl cyanide having an alkyl group with 1 to 15 carbon atoms or a linear or cyclic saturated hydrocarbon having 3 to 15 carbon atoms and substituted with one or more nitrogen (N), oxygen (O), phosphorus (O) or sulfur (S) in an organic solvent to synthesize a coordination compound represented by chemical formula 1.

[0021] [Chemical formula 2]

[0022] MX a Y (6-a)

[0023] Wherein, M is niobium (Nb), tungsten (W) or molybdenum (Mo); X is a halogen element; Y is an amine; and a is an integer of 1 to 6.

[0024] In addition, the present invention provides a method for preparing a thin film, which includes the following steps: injecting the thin film forming precursor of the present invention into a CVD chamber or an ALD chamber and allowing it to be adsorbed on the surface of a loaded substrate; using a purge gas to purge the residual thin film forming precursor that has not been adsorbed; providing a reaction gas and allowing it to react with the thin film forming precursor adsorbed on the surface of the substrate to generate a metal thin film layer; and using a purge gas to purge the reaction by-products.

[0025] Beneficial Effects

[0026] According to the present invention, a thin film forming precursor, a preparation method thereof and a thin film preparation method containing the same can be provided. The thin film forming precursor is liquid at room temperature and has strong volatility, so the deposition speed is very fast, and it is easy to handle when injected into a thin film deposition chamber, especially it has excellent thermal stability, so it can prepare a thin film with high purity and excellent step coverage. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a process diagram for explaining an ALD process according to an embodiment of the present invention.

[0028] Figure 2 These are photographs of the thin film-forming precursor prepared in Example 1 of the present invention before and after drying.

[0029] Figure 3 This is a graph obtained by DSC analysis of the thin film forming precursor prepared in Example 1 of the present invention.

[0030] Figure 4 This is a graph obtained by TGA analysis of the thin film forming precursor prepared in Example 1 of the present invention.

[0031] Figure 5 These are NMR spectra measured before and after the thin film forming precursor prepared in Example 1 of the present invention was left to stand at 150° C. for 1 hour.

[0032] Figure 6 This is a graph obtained by DSC analysis of the thin film forming precursor prepared in Example 2 of the present invention.

[0033] Figure 7 This is a graph obtained by TGA analysis of the thin film forming precursor prepared in Example 2 of the present invention.

[0034] Figure 8 These are NMR spectra measured before and after the thin film forming precursor prepared in Example 2 of the present invention was left to stand at 150° C. for 1 hour. DETAILED DESCRIPTION

[0035] Hereinafter, the thin film forming precursor, the production method thereof, and the thin film production method including the same according to the present disclosure will be described in detail.

[0036] The inventors of the present invention have confirmed that when niobium metal and the like are coordinated with a predetermined ligand, they are in a liquid phase at room temperature or are easily liquefied by a predetermined solvent, and have further confirmed that when such a coordinated metal compound is used as a thin film forming precursor to form a metal thin film, it is in a liquid phase at room temperature and has strong volatility, so the deposition rate is very fast, and when injected into a thin film deposition chamber, it is easy to handle, and in particular has excellent thermal stability, so that a thin film with high purity and excellent step coverage can be prepared. Based on this, further research was conducted and the present invention was completed.

[0037] The thin film forming precursor of the present invention is liquid at 20° C. and 1 bar, and contains 20 to 100 wt % of the coordination compound represented by Chemical Formula 1 and 0 to 80 wt % of an alkyl cyanide having an alkyl group with 1 to 15 carbon atoms.

[0038] [Chemical formula 1]

[0039] MX n L m Y z

[0040] Wherein, M is niobium (Nb), tungsten (W) or molybdenum (Mo); X is a halogen element; n is an integer of 1 to 6; L is an alkyl cyanide having an alkyl group with 1 to 15 carbon atoms, or a linear or cyclic saturated hydrocarbon having 3 to 15 carbon atoms and substituted with one or more nitrogen (N), oxygen (O), phosphorus (O) or sulfur (S); m is an integer of 1 to 3; the bonded Y is an amine; z is an integer of 0 to 4; n+z is an integer of 3 to 6. When such a thin film forming precursor is used to prepare a metal thin film, it is liquid at room temperature and highly volatile, so the deposition speed is very fast, and the viscosity or vapor pressure is easy to adjust, so it is easy to handle when injected into a thin film deposition chamber, and in particular, it has excellent thermal stability, so it is not easily decomposed, and a thin film with high purity and excellent step coverage can be prepared.

[0041] As another example, in the chemical formula 1, n is an integer of 2 to 4, m is an integer of 1 to 3, z is an integer of 1 to 3, and n+m+z is 6.

[0042] In the coordination compound, X is preferably fluorine, n is preferably 5, and m can be 1. In this case, it is liquid at room temperature, highly volatile, and has excellent thermal stability, thus having the advantages of fast deposition speed, low processing difficulty, and excellent film purity and step coverage.

[0043] In the coordination compound, L is preferably an alkyl cyanide having an alkyl group with 1 to 5 carbon atoms, and more preferably an alkyl cyanide having an alkyl group with 3 to 5 carbon atoms. Within this range, the alkyl group has the advantage of being easily liquefied.

[0044] As another example, in the coordination compound, L is preferably a linear or cyclic saturated hydrocarbon having 3 to 10 carbon atoms and substituted with one or more nitrogen (N) or oxygen (O), and more preferably a linear or cyclic saturated hydrocarbon having 4 to 8 carbon atoms and substituted with one or more nitrogen (N) or oxygen (O). As a specific example, it can be diethyl ether, tetrahydrofuran, etc. Within this range, there is an advantage that the precursor for thin film formation can be easily liquefied.

[0045] In the present description, a saturated hydrocarbon is substituted with one or more nitrogen (N), oxygen (O), phosphorus (O) or sulfur (S), which means that nitrogen (N), oxygen (O), phosphorus (O) or sulfur (S) is inserted and bonded between atoms of the saturated hydrocarbon or replaces a hydrogen atom, a carbon atom, a CH group or a CH2 group in the saturated hydrocarbon.

[0046] The L preferably serves as a ligand.

[0047] In the coordination compound, Y is preferably a secondary amine, more preferably a dialkylamine. As a specific example, it can be one or more selected from diethylamine, dimethylamine, ethylmethylamine, dipropylamine, etc. Within this range, it has the advantage of being easily liquefied.

[0048] The coordination compound is preferably of chemical formula 1a, more preferably of chemical formula 1b. When a thin film forming precursor is used to prepare a metal thin film, it is liquid at room temperature and has strong volatility, so the deposition speed is very fast, and the viscosity or vapor pressure is easy to adjust, so it is easy to handle when injected into a thin film deposition chamber. In particular, it has excellent thermal stability, so it is not easy to be decomposed, and can prepare a thin film with high purity and excellent step coverage.

[0049] [Chemical formula 1a]

[0050] MX n L m Y z

[0051] Wherein, M is niobium (Nb), tungsten (W) or molybdenum (Mo); X is a halogen element; n is an integer of 1 to 6; L is an alkyl cyanide having an alkyl group with 1 to 15 carbon atoms; m is an integer of 1 to 3; Y is an amine; z is an integer of 0 to 4; and n+m+z is 6.

[0052] [Chemical formula 1b]

[0053] MX n L m

[0054] Wherein, M is niobium (Nb), tungsten (W) or molybdenum (Mo); X is a halogen element; n is an integer of 3 to 6; L is an alkyl cyanide having an alkyl group with 1 to 15 carbon atoms; m is an integer of 1 to 3; and n+m is 6.

[0055] As another example, the n may be an integer of 3-5.

[0056] The final temperature (T f ) is preferably 180° C. or higher, more preferably 180 to 250° C., and more preferably 190 to 230° C. Within this range, the purity is excellent and the step coverage is excellent.

[0057] The residue of the thin film forming precursor measured by a thermogravimetric analyzer (TGA) is preferably less than 3 wt %, more preferably less than 2 wt %, more preferably less than 2 wt %, and most preferably less than 1 wt %. Within this range, it has the advantage of excellent thermal stability.

[0058] The exothermic temperature of the thin film forming precursor measured by differential scanning calorimetry (DSC) is preferably 150° C. or higher, more preferably 150 to 230° C., and even more preferably 160 to 210° C. Within this range, excellent thermal stability is achieved.

[0059] The method for preparing a thin film forming precursor of the present invention comprises the following steps: reacting a compound represented by Chemical Formula 2 with an alkyl cyanide having an alkyl group with 1 to 15 carbon atoms or a linear or cyclic saturated hydrocarbon having 3 to 15 carbon atoms and substituted with one or more nitrogen (N), oxygen (O), phosphorus (O) or sulfur (S) in an organic solvent to synthesize a coordination compound represented by Chemical Formula 1. In this case, it has the advantage that a thin film forming precursor can be prepared, which is liquid at room temperature and highly volatile, so the deposition speed is very fast, and it is easy to handle when injected into a thin film deposition chamber, and in particular, has excellent thermal stability, so that a thin film with high purity and excellent step coverage can be prepared.

[0060] [Chemical formula 1]

[0061] MX n L m Y z

[0062] Wherein, M is niobium (Nb), tungsten (W) or molybdenum (Mo); X is a halogen element; n is an integer of 1 to 6; L is an alkyl cyanide having an alkyl group with 1 to 15 carbon atoms, or a linear or cyclic saturated hydrocarbon having 3 to 15 carbon atoms and substituted by one or more nitrogen (N), oxygen (O), phosphorus (O) or sulfur (S); m is an integer of 1 to 3; the bonded Y is an amine; z is an integer of 0 to 4; and n+z is an integer of 3 to 6.

[0063] [Chemical formula 2]

[0064] MX a Y (6-a)

[0065] Wherein, M is niobium (Nb), tungsten (W) or molybdenum (Mo); X is a halogen element; Y is an amine; and a is an integer of 1 to 6.

[0066] The contents of the thin film forming precursor of the present invention described above are also applicable to the production method thereof, and therefore, repeated description is omitted here.

[0067] The organic solvent is preferably a halogenated hydrocarbon, more preferably a halogenated hydrocarbon having an alkyl group with 1 to 5 carbon atoms, and more preferably a halogenated methyl ether. In this case, there is an effect that the synthesis of the thin film forming precursor can be stably performed.

[0068] The content of the alkyl cyanide or the saturated hydrocarbon may be 20 to 40 wt %, more preferably 25 to 40 wt %, and more preferably 25 to 33 wt %, relative to 100 wt % in total of the compound represented by the chemical formula 2 and the alkyl cyanide or the saturated hydrocarbon. Within this range, the thin film forming precursor has the advantage of being easily liquefied.

[0069] As another example, based on the compound represented by the chemical formula 2, the content of the alkyl cyanide or the saturated hydrocarbon can be 1 to 1.5 equivalents (eq.), more preferably 1.0 to 1.2 equivalents (eq.), and more preferably 1.0 to 1.1 equivalents (eq.). Within this range, there is an advantage that the precursor for thin film formation can be easily liquefied.

[0070] The synthesis is preferably carried out at 15 to 25° C., more preferably at 20 to 25° C., and even more preferably at 20 to 23° C. Within this range, there is an effect that the synthesis of the thin film forming precursor can be stably performed.

[0071] As one example, the synthesis can be carried out for more than 30 minutes, preferably more than 1 hour. As another example, it can be carried out for less than 10 hours, preferably less than 5 hours, and more preferably less than 2 hours. Within this range, the synthesis of the thin film forming precursor can be stably carried out.

[0072] Preferably, the method for preparing the thin film forming precursor comprises the steps of filtering the synthesized solution and evaporating the filtrate obtained after the filtration under reduced pressure to obtain the coordination compound represented by the chemical formula 1. In this case, the thin film forming precursor is easily liquefied.

[0073] The reduced pressure evaporation is preferably carried out at 80-150° C. and 0.1-100 torr, more preferably at 100-150° C. and 0.5-10 torr, and even more preferably at 110-130° C. and 0.5-5 torr. Within this range, the thin film forming precursor is easily liquefied.

[0074] Preferably, the method for preparing the thin film forming precursor further comprises the step of mixing the obtained coordination compound with an alkyl cyanide having an alkyl group with carbon atoms of 1 to 15 to dilute the complex. In this case, the thin film forming precursor can be easily liquefied.

[0075] The thin film preparation method of the present invention comprises the following steps: injecting the thin film forming precursor of the present invention into a CVD chamber or an ALD chamber and adsorbing it on the surface of a loaded substrate; using a purge gas to purge the residual thin film forming precursor that has not been adsorbed; providing a reaction gas and reacting it with the thin film forming precursor adsorbed on the surface of the substrate to generate a metal thin film layer; and using a purge gas to purge the reaction byproducts. In this case, the deposition speed of the thin film forming precursor is very fast and easy to handle, and a thin film with excellent step coverage can be prepared.

[0076] As a specific example, the film preparation method of the present film can be described in the following Figure 1The process sequence is as follows, but not limited to.

[0077] As an example, the thin film forming precursor may be mixed with a non-polar solvent and then injected into the chamber to adjust the viscosity or vapor pressure.

[0078] The substrate is preferably a dielectric film. In this case, there is an advantage that the electrostatic capacitance (Cs) of the capacitor finally manufactured is excellent.

[0079] As an example, the dielectric film can be formed of a high dielectric constant material, preferably HfO2, Al2O3, TiO2, ZrO2, Ta2O5 or Y2O3, and more preferably HfO2.

[0080] The non-polar solvent may be one or more selected from alkanes and cycloalkanes. In this case, the non-polar solvent has the advantages of containing an organic solvent with low reactivity and solubility and easy water management, and when forming a thin film, the step coverage can be improved even if the deposition temperature is increased.

[0081] More preferably, the non-polar solvent may include C1-C10 alkane or C3-C10 cycloalkane, preferably C3-C10 cycloalkane. In this case, it has the advantages of low reactivity and solubility and easy water management.

[0082] In the present description, C1, C3, etc. represent the number of carbon atoms.

[0083] The cycloalkane is preferably a C3-C10 monocycloalkane, and cyclopentane among the monocycloalkane is liquid at room temperature and has the highest vapor pressure, and is preferred in the vapor deposition process, but is not limited thereto.

[0084] As an example, the solubility of the non-polar solvent in water (25°C) can be less than 200 mg / L, preferably 50 to 200 mg / L, and more preferably 135 to 175 mg / L. Within this range, it has the advantages of low reactivity with thin film forming precursors and easy water management.

[0085] In the present description, the solubility is not particularly limited as long as it follows the measurement method or standard conventionally used in the technical field to which the present invention belongs. As an example, a saturated solution can be measured by HPLC.

[0086] The content of the nonpolar solvent may be 5 to 95 wt %, more preferably 10 to 90 wt %, more preferably 40 to 90 wt %, and most preferably 70 to 90 wt % relative to the total weight of the film-forming precursor and the nonpolar solvent.

[0087] If the content of the non-polar solvent is greater than the upper limit, impurities will be induced, resulting in an increase in resistance and impurity values ​​in the film. When the content of the organic solvent is less than the lower limit, the disadvantage is that the effect of improving step coverage and reducing impurities such as chloride (C1) ions due to the addition of solvent is poor.

[0088] As an example, the film growth rate per cycle of the film preparation method calculated according to Mathematical Formula 1 is The reduction rate is below -5%, preferably below -10%, more preferably below -20%, more preferably below -30%, more preferably below -40%, and most preferably below -45%. Within this range, the step coverage and film thickness uniformity are excellent.

[0089] [Mathematical formula 1]

[0090] Reduction rate of film growth rate per cycle (%) = [(film growth rate per cycle when using a film growth inhibitor - film growth rate per cycle when not using a film growth inhibitor) / film growth rate per cycle when not using a film growth inhibitor] × 100

[0091] The residual halogen intensity (c / s) in the thin film formed after 200 cycles measured by SIMS of the thin film preparation method is preferably 10,000 or less, more preferably 8,000 or less, more preferably 7,000 or less, and more preferably 6,000 or less. Within this range, the effect of preventing corrosion and degradation is excellent.

[0092] In the present description, the purge is preferably 1,000 to 10,000 sccm, more preferably 2,000 to 7,000 sccm, and even more preferably 2,500 to 6,000 sccm. Within this range, the film growth rate per cycle is reduced to a preferred range and process byproducts are reduced.

[0093] The ALD (atomic layer deposition process) is very advantageous in the manufacture of integrated circuits (IC) requiring a high aspect ratio, especially because of its self-limiting film growth mechanism, which has advantages such as excellent step conformality, uniformity, and precise thickness control.

[0094] As an example, the thin film preparation method can be implemented at a deposition temperature in the range of 50 to 900°C, preferably in the range of 300 to 700°C, more preferably in the range of 350 to 600°C, more preferably in the range of 400 to 550°C, and more preferably in the range of 400 to 500°C. Within this range, the effect of realizing ALD process characteristics and growing a thin film with excellent film quality is obvious.

[0095] As an example, the thin film preparation method can be implemented at a deposition pressure in the range of 0.1 to 10 Torr, preferably in the range of 0.5 to 5 Torr, and most preferably in the range of 1 to 3 Torr. Within this range, a thin film with uniform thickness can be obtained.

[0096] In this description, the deposition temperature and the deposition pressure may be the measured temperature and pressure formed in the deposition chamber, or the measured temperature and pressure applied to the substrate in the deposition chamber.

[0097] Preferably, the thin film preparation method includes the following steps: before the thin film forming precursor is put into the chamber, the temperature in the chamber is increased to the deposition temperature; and / or before the thin film forming precursor is put into the chamber, an inert gas is injected into the chamber for purging.

[0098] The thin film production method will be described using specific examples.

[0099] First, a substrate on which a thin film is to be formed is placed in a deposition chamber capable of performing atomic layer deposition.

[0100] The substrate may include a semiconductor substrate such as a silicon substrate or silicon oxide.

[0101] The substrate may further have a conductive layer or an insulating layer formed on an upper portion thereof.

[0102] The thin film forming precursor or a mixture thereof with a non-polar solvent is prepared to deposit a thin film on a substrate in the deposition chamber.

[0103] Then, the prepared thin film forming precursor or a mixture thereof with a nonpolar solvent is injected into a vaporizer, converted into a vapor phase, and transferred to a deposition chamber to be adsorbed onto a substrate, and then the unadsorbed thin film forming composition is purged.

[0104] In this description, as an example, the method for transferring thin film forming precursors and the like to the deposition chamber can adopt a method of transferring volatile gas (Vapor Flow Control; VFC) using a gas phase flow control (Mass Flow Controller; MFC) method or a method of transferring liquid (Liquid Delivery System; LDS) using a liquid phase flow control (Liquid Mass Flow Controller; LMFC) method, and the LDS method is preferably used.

[0105] At this time, the carrier gas or dilution gas used to move the thin film forming precursor etc. onto the substrate can use one or a mixed gas of two or more selected from argon (Ar), nitrogen (N2), helium (He), but is not limited thereto.

[0106] In the present description, as an example, an inert gas may be used as the purge gas, but the above-mentioned carrier gas or diluent gas is preferably used.

[0107] Next, a reaction gas is supplied. The reaction gas is not particularly limited as long as it is a reaction gas conventionally used in the technical field to which the present invention belongs, and preferably includes a reducing agent, a nitriding agent, or an oxidizing agent. The reducing agent reacts with the film-forming precursor adsorbed on the substrate to form a metal film, the nitriding agent forms a metal nitride film, and the oxidizing agent forms a metal oxide film.

[0108] Preferably, the reducing agent may be ammonia (NH3) or hydrogen (H2), the nitriding agent may be nitrogen (N2), and the oxidizing agent may be one or more selected from H2O, H2O2, O2, O3 and N2O.

[0109] Next, the unreacted residual reaction gas is purged with an inert gas, thereby removing not only the excess reaction gas but also the generated by-products.

[0110] As described above, the steps of adsorbing the thin film forming precursor on the substrate, purging the unadsorbed thin film forming composition, supplying the reaction gas, and purging the residual reaction gas can be used as a unit cycle, and the unit cycle can be repeated to form a thin film of desired thickness.

[0111] As an example, the unit cycle may be 100 to 1000 times, preferably 100 to 500 times, and more preferably 150 to 300 times. Within this range, the target film properties can be well exhibited.

[0112] The semiconductor substrate of the present invention is manufactured by the thin film manufacturing method described herein. In this case, corrosion and degradation are prevented and the step coverage and uniformity of the thin film thickness are excellent.

[0113] The semiconductor substrate is preferably a thin film capacitor or a semiconductor device capacitor.

[0114] Preferably, the thickness of the thin film prepared above is less than 20nm, the resistivity is 0.1-400μΩ·cm, the halogen content is less than 10,000ppm, and the step coverage is more than 90%. Within this range, it has excellent performance as an anti-diffusion film and the effect of reducing corrosion of metal wiring materials, but is not limited to this.

[0115] As an example, the thickness of the thin film is 5 to 20 nm, preferably 10 to 20 nm, more preferably 15 to 18.5 nm, and even more preferably 17 to 18.5 nm. Within this range, the film has excellent properties.

[0116] As an example, the resistivity of the film is 0.1 to 400 μΩ·cm, preferably 50 to 400 μΩ·cm, more preferably 200 to 400 μΩ·cm, more preferably 300 to 400 μΩ·cm, more preferably 330 to 380 μΩ·cm, and most preferably 340 to 370 μΩ·cm. Within this range, the film has excellent properties.

[0117] The halogen content of the film is preferably 9,000 ppm or less or 1 to 9,000 ppm, more preferably 8,500 ppm or less or 100 to 8,500 ppm, and even more preferably 8,200 ppm or less or 1,000 to 8,200 ppm. Within this range, the film has excellent properties and corrosion of metal wiring materials is reduced.

[0118] As an example, the step coverage of the film is above 80%, preferably above 90%, and more preferably above 93%. Within this range, the advantage is that even if the film structure is complex, it can be easily deposited on the substrate, so it can be applied to the next generation of semiconductor devices.

[0119] As an example, the thin film prepared above can be a NbN thin film or a NbO2 thin film, preferably NbN.

[0120] Below, preferred embodiments and drawings are proposed to facilitate understanding of the present invention. The following embodiments and drawings are only used to illustrate the present invention. Those skilled in the art will appreciate that various changes and modifications can be made within the scope of the present invention and the technical concept, and these changes and modifications should naturally fall within the scope of the appended claims.

[0121] [Example]

[0122] <Synthesis of Thin Film Forming Precursor>

[0123] Example 1 (Preparation of Niobium Coordination Compound Coordinated with 2-Methylbutyronitrile)

[0124] In a glove box, 137 g (0.73 mol, 1 equivalent) of Niobium fluoride (V) as a starting material was weighed into a 3 L flask. The starting material was diluted with 0.5 M (1.5 L) of dichloromethane as a solvent. After injecting 74 mL (0.73 mol, 1 equivalent) of the desired ligand 2-methylbutyronitrile into it, it was stirred at room temperature for 1 hour and then filtered. After removing the solvent in the obtained filtrate by reduced pressure distillation, the desired precursor was obtained in the form of a colorless liquid (158 g) with a yield of 80% through a purification process (at 70°C and 1.0 Torr).

[0125] Example 2 (Preparation of niobium coordination compound coordinated with 2,2-dimethylvaleronitrile)

[0126] In a glove box, 126 g (0.67 mol, 1 equivalent) of niobium fluoride (V) as a starting material was weighed into a 3 L flask. The starting material was diluted with 0.5 M (1.4 L) of dichloromethane as a solvent. 92 mL (0.67 mol, 1 equivalent) of the ligand to be coordinated (2,2-dimethylvaleronitrile) was injected therein, and the mixture was stirred at room temperature for 1 hour and then filtered. After the solvent in the obtained filtrate was removed by reduced pressure distillation, the desired precursor was obtained in the form of a colorless liquid (160 g) with a yield of 80% through a purification process (at 70° C. and 1.0 Torr).

[0127] [Experimental example]

[0128] The dry state, DSC analysis, TGA analysis and NMR analysis of the thin film forming precursors prepared in Examples 1 and 2 were performed, and the results are shown in FIG. Figure 2 to Figure 8 .

[0129] Figure 2 These are photographs of the thin film forming precursor prepared in Example 1 before and after drying. It can be confirmed that even after drying (Dry), that is, even when no alkyl cyanide as a solvent is included, it is still in a liquid state as before drying (Solution).

[0130] Figure 3 This is a graph obtained by DSC analysis of the thin film forming precursor prepared in Example 1. The exothermic temperature is 150°C. It is a liquid at room temperature and has strong volatility. Therefore, the deposition speed is very fast. When injected into the thin film deposition chamber, it is easy to handle, especially the thermal stability is excellent. Therefore, it is easy to predict that a thin film with high purity and excellent step coverage can be prepared.

[0131] Figure 4 This is a graph obtained by TGA analysis of the thin film forming precursor prepared in Example 1. The final temperature (To) is 200°C, and the residue is less than 3% by weight, which confirms high thermal stability and excellent purity. The characteristic part is that if the thermal stability of the prepared thin film forming precursor decreases and the coordinated ligand is separated from the niobium metal, a 2-pattern will appear, but the thin film forming precursor of the present invention prepared in Example 1 obtained a 1-pattern step-shaped graph, so it can be confirmed that no thermal decomposition has occurred.

[0132] Figure 5 This is the NMR spectrum of the thin film forming precursor prepared in Example 1. From the result, it can be confirmed that the desired niobium complex coordinated with 2-methylbutyronitrile has been prepared.

[0133] Figure 6 This is a graph obtained by DSC analysis of the thin film forming precursor prepared in Example 2. The exothermic temperature is 150°C. It is a liquid at room temperature and has strong volatility. Therefore, the deposition speed is very fast. When injected into the thin film deposition chamber, it is easy to handle, especially the thermal stability is excellent. Therefore, it is easy to predict that a thin film with high purity and excellent step coverage can be prepared.

[0134] Figure 7 This is a graph obtained by TGA analysis of the thin film forming precursor prepared in Example 2. The final temperature (To) is 200°C and the residue is less than 3% by weight. It can be confirmed that the thermal stability is high and the purity is excellent, and it is suitable for preparing high-quality thin films.

[0135] Figure 8This is the NMR spectrum of the thin film forming precursor prepared in Example 2. From the result, it can be confirmed that the desired niobium complex coordinated with 2,2-dimethylvaleronitrile has been prepared.

[0136] In summary, it can be confirmed that the thin film forming precursor of the present invention is liquid at room temperature and has strong volatility, so the deposition speed is very fast, and when injected into the thin film deposition chamber, it is easy to handle, especially with excellent thermal stability, so it can prepare a thin film with high purity and excellent step coverage.

Claims

1. A thin film forming precursor, characterized in that: It is liquid at 20℃ and 1bar. and containing 20 to 100 wt % of the coordination compound represented by Chemical Formula 1 and 0 to 80 wt % of an alkyl cyanide having an alkyl group with 1 to 15 carbon atoms, [Chemical formula 1] MX n L m Y z Wherein, M is niobium (Nb), tungsten (W) or molybdenum (Mo); X is a halogen element; n is an integer of 1 to 6; L is an alkyl cyanide having an alkyl group with 1 to 5 carbon atoms; m is an integer of 1 to 3; the combined Y is a secondary amine; z is an integer of 1 to 3; and n+m+z is an integer of 3 to 6.

2. The thin film forming precursor according to claim 1, wherein In the coordination compound, X is fluorine and n is 5.

3. The thin film forming precursor according to claim 1, wherein The final temperature (T f ) is above 180°C.

4. The thin film forming precursor according to claim 1, wherein The residue of the thin film-forming precursor measured by a thermogravimetric analyzer was less than 3 wt %.

5. The thin film forming precursor according to claim 1, wherein The exothermic temperature of the thin film forming precursor measured by a differential scanning calorimeter is 150° C. or higher.

6. A method for preparing a thin film forming precursor, characterized in that: The steps include: The compound represented by Chemical Formula 2 is reacted with an alkyl cyanide having an alkyl group with 1 to 5 carbon atoms in a halogenated hydrocarbon solvent to synthesize a coordination compound represented by Chemical Formula 1, [Chemical formula 1] MX n L m Y z Wherein, M is niobium (Nb), tungsten (W) or molybdenum (Mo); X is a halogen element; n is an integer of 1 to 6; L is an alkyl cyanide having an alkyl group with 1 to 5 carbon atoms; m is an integer of 1 to 3; the bonded Y is a secondary amine; z is an integer of 1 to 3; n+m+z is an integer of 3 to 6, [Chemical formula 2] MX a Y (6-a) Wherein, M is niobium (Nb), tungsten (W) or molybdenum (Mo); X is a halogen element; Y is a secondary amine; and a is an integer of 1 to 6.

7. The method for preparing a thin film forming precursor according to claim 6, wherein: The content of the alkyl cyanide is 20 to 40 wt % relative to 100 wt % in total of the compound represented by Chemical Formula 2 and the alkyl cyanide.

8. The method for preparing a thin film forming precursor according to claim 6, wherein: The synthesis was carried out at 15-25°C.

9. The method for preparing a thin film forming precursor according to claim 6, wherein: The steps include: filtering the resulting solution; and The filtrate obtained after the filtration is evaporated under reduced pressure to obtain the coordination compound represented by the chemical formula 1.

10. The method for preparing a thin film forming precursor according to claim 9, wherein: Further comprising the steps of: The obtained coordination compound is mixed with an alkyl cyanide having an alkyl group with 1 to 15 carbon atoms to be diluted.

11. A method for preparing a thin film, characterized in that: The steps include: Injecting the thin film forming precursor according to any one of claims 1 to 5 into a CVD chamber or an ALD chamber and adsorbing it on the surface of the loaded substrate; Using a purge gas, the unadsorbed residual thin film forming precursor is purged; Providing a reaction gas and causing it to react with a thin film forming precursor adsorbed on the surface of the substrate, thereby generating a metal thin film layer; as well as The reaction byproducts are purged using a purge gas.

12. The thin film preparation method according to claim 11, characterized in that: The reaction gas is a reducing agent, a nitriding agent or an oxidizing agent.

13. The method for preparing a thin film according to claim 11, characterized in that: The thin film forming precursor is transferred to the substrate surface by a VFC method, a DLI method, or an LDS method.

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