Method for forming metal nitride thin film

Abstract

A method for forming a metal nitride thin film according to an embodiment of the present invention comprises: a substrate preparation step for preparing a substrate in a process chamber in which a processing space is formed; a thin-film formation step for forming a metal nitride thin film on the substrate by supplying each of a metal precursor gas and a nitrogen-containing gas; a first surface treatment step for surface-treating the metal nitride thin film at least once by supplying a hydrogen-containing gas to the process chamber and forming a first plasma; and a second surface treatment step for surface-treating the first surface-treated substrate at least once by supplying a nitrogen-containing gas to the process chamber and forming a second plasma.

Description

Method for forming a metal nitride thin film

[0001] The present invention relates to a method for forming a metal nitride thin film.

[0002] Recently, with the miniaturization and increased integration of semiconductor devices, there is a growing demand for methods to reduce the number and size of particles and improve film quality. In particular, for metal nitride thin films, such as titanium nitride thin films, film quality and yield management are becoming increasingly important.

[0003] Typically, the metal nitride thin film is formed using a chemical vapor deposition (CVD) method, which supplies a metal source gas and a nitrogen-containing gas into a reaction chamber and thermally reacts them to form a thin film on a substrate. Immediately after depositing the metal nitride thin film, hydrogen plasma is used to remove residues of the metal precursor with a slow flow rate, thereby improving the level of residues and particles within the film.

[0004] However, when forming a thick metal nitride thin film using the existing method as described above, there is a problem that cracks easily occur in the thin film due to high stress and a film with high resistance is formed, so research is needed on a method that can complement this.

[0005] According to one embodiment, the present invention provides a method for forming a metal nitride thin film, which can form a thin film having low stress and resistance even when forming a thick metal nitride thin film, and can also prevent the occurrence of defects such as cracks.

[0006] A method for forming a metal nitride thin film according to an embodiment comprises: a substrate preparation step of preparing a substrate into a process chamber in which a processing space is formed; a thin film formation step of forming a metal nitride thin film on an upper portion of the substrate by respectively supplying a metal precursor gas and a nitrogen-containing gas; a first surface treatment step of supplying a hydrogen-containing gas to the process chamber and forming a first plasma to surface-treat the metal nitride thin film at least once; and a second surface treatment step of supplying a nitrogen-containing gas to the process chamber and forming a second plasma to surface-treat the substrate subjected to the first surface treatment at least once.

[0007] According to one embodiment, the thin film forming step of forming a metal nitride thin film on the upper portion of the substrate may be performed by reacting the metal precursor gas and the nitrogen-containing gas using a thermal chemical vapor deposition (thermal CVD) method performed at a temperature of 300 to 800° C. to form the metal nitride thin film.

[0008] According to one embodiment, the metal nitride thin film may include any one of titanium nitride (TiN), tungsten nitride (WN), molybdenum nitride (Mo2N), tantalum nitride (TaN), aluminum nitride (AlN), and titanium aluminum nitride (TiAlN).

[0009] In one embodiment, the metal precursor gas may include at least one metal precursor selected from the group consisting of titanium tetrachloride (TiCl4), tetrakis dimethylamino titanium (TDMAT, Ti(N(Me2)4)), tetrakis diethylamino titanium (TDEAT, Ti(N(Et2)4)), and tetrakis ethylmethylamino titanium (TEMAT, Ti(N(EtMe)4)).

[0010] In one embodiment, the nitrogen-containing gas may include at least one of ammonia (NH3) gas and nitrogen (N2) gas (N2).

[0011] According to one embodiment, the first surface treatment step and the second surface treatment step may form the first plasma and the second plasma, respectively, by applying a dual frequency power source, and in particular, the first plasma and the second plasma, respectively, may be formed by applying at least one of a high frequency or an ultra-high frequency and a low frequency.

[0012] According to one embodiment, the second surface treatment step can be performed by supplying not only a nitrogen-containing gas, but also a hydrogen-containing gas.

[0013] In a method for forming a metal nitride thin film according to an embodiment, a metal nitride thin film deposited by a thermal chemical vapor deposition method is subjected to a first surface treatment using hydrogen plasma to remove a metal precursor gas having a slow flow rate. Through the first surface treatment process, the concentration of residual ions and contaminants in the film quality of the metal nitride thin film can be reduced and the level of particles can be improved. In addition, the metal nitride thin film subjected to the first surface treatment is subjected to a second surface treatment using a second plasma. Through the second surface treatment process, the stress of the film quality can be reduced, crack occurrence can be prevented, and surface resistance can be lowered. Accordingly, the method for forming a metal nitride thin film according to an embodiment can form a metal nitride thin film having improved electrical, chemical, and physical properties.

[0014] Figure 1 is a process diagram showing a method for forming a metal nitride thin film according to an embodiment.

[0015] Fig. 2 is a timing diagram showing a method for forming a metal nitride thin film according to an embodiment.

[0016] FIG. 3 is a graph showing the ion energy distribution and ion energy by frequency to explain the ion energy formed by plasma in the method for forming a metal nitride thin film according to an embodiment.

[0017] Fig. 4 is a graph showing a time-dependent overlapping waveform for each voltage formed by a dual frequency power source in a method for forming a metal nitride thin film according to an embodiment.

[0018] Fig. 5 is a graph showing changes in ion energy distribution when dual frequency power is applied in a method for forming a metal nitride thin film according to an embodiment.

[0019] Fig. 6 is a schematic diagram showing a substrate processing device according to one embodiment.

[0020] Figure 7 is SIMS data showing the results of evaluating the chloride ion concentration of a thin film formed by the method according to Examples 1 to 3.

[0021] Figure 8 is an electron microscope image of the surface of a thin film formed by a method according to (a) Comparative Example, (b) Example 1, (c) Example 2, and (d) Example 3.

[0022] Fig. 1 is a process diagram showing a method for forming a metal nitride thin film according to an embodiment. Fig. 2 is a timing diagram showing an example of a method for forming a metal nitride thin film according to an embodiment.

[0023] Referring to FIGS. 1 and 2, a method for forming a metal nitride thin film according to an embodiment includes a substrate preparation step (S100) of preparing a substrate (S) into a process chamber (100) in which a processing space is formed; a thin film formation step (S200) of forming a metal nitride thin film on the upper portion of the substrate (S); a first surface treatment step (S300) of subjecting the metal nitride thin film to a first surface treatment; and a second surface treatment step (S400) of subjecting the substrate (S) to a second surface treatment after the first surface treatment. The method for forming a metal nitride thin film according to an embodiment can be performed using various types of conventional substrate treatment devices utilized to form a metal nitride thin film on a substrate (S). In addition, the substrate treatment device can be utilized to perform a plasma enhanced chemical vapor deposition process.

[0024] First, in the substrate preparation step (S100), the substrate (S) is placed on the substrate placement unit (130) installed in the processing space of the process chamber.

[0025] The above substrate (S) may be a typical substrate of various types used for manufacturing semiconductor devices by forming a metal nitride thin film on the upper surface.

[0026] Next, in the thin film formation step (S200), a metal precursor gas and a nitrogen-containing gas are respectively supplied onto the substrate (S) to form a metal nitride thin film on the upper portion of the substrate (S).

[0027] In this step, a metal precursor gas and a nitrogen-containing gas are supplied separately and reacted to form the metal nitride thin film. In this step, the metal precursor gas and the nitrogen-containing gas can be reacted using a thermal chemical vapor deposition method performed at a temperature of 300 to 800°C to form the metal nitride thin film. In particular, this step can be performed at a temperature of 500 to 700°C.

[0028] The above metal nitride thin film may include at least one of titanium nitride (TiN), tungsten nitride (WN), molybdenum nitride (Mo2N), tantalum nitride (TaN), aluminum nitride (AlN), and titanium aluminum nitride (TiAlN).

[0029] The above metal precursor gas can supply various conventional metal precursor gases utilized to form a metal nitride thin film.

[0030] In particular, the metal nitride thin film may be a titanium nitride thin film. Accordingly, the metal precursor gas may include a metal precursor including at least one of titanium tetrachloride (TiCl4), tetrakis dimethylamino titanium (TDMAT, Ti(N(Me2)4)), tetrakis diethylamino titanium (TDEAT, Ti(N(Et2)4)), and tetrakis ethylmethylamino titanium (TEMAT, Ti(N(EtMe)4)).

[0031] The above nitrogen-containing gas may include at least one of ammonia (NH3) gas and nitrogen (N2) gas.

[0032] When forming a metal nitride thin film using the above thermal chemical vapor deposition method, there is a problem that the metal nitride thin film is prone to cracking due to high stress and forms a film with high resistance. In the method for forming a metal nitride thin film according to an embodiment, a PECVD process is introduced to surface-treat the metal nitride thin film using a first plasma and a second plasma, respectively, so that a metal nitride thin film with excellent physical properties can be formed.

[0033] Next, the first surface treatment step (S300) can perform the first surface treatment on the metal nitride thin film by supplying a hydrogen-containing gas to the process chamber (110) and forming a first plasma.

[0034] In this step, a hydrogen-containing gas is supplied and a first plasma is formed to perform a first surface treatment on the metal nitride thin film. The first surface treatment removes residual metal precursor gases with slow flow rates, thereby reducing the concentration of residual ions and contaminants within the film of the metal nitride thin film and improving the particle level. At this time, the hydrogen-containing gas may be hydrogen (H2) gas.

[0035] In this step, in order to perform the first surface treatment on the metal nitride thin film, at least one of low frequency power (LF), high frequency power (HF), and very high frequency power (VHF) may be applied to form the first plasma.

[0036] According to one embodiment, in this step, the first plasma can be formed by applying a dual frequency power source. The first plasma can be formed by applying a high frequency (HF) power source and a low frequency (LF) power source. In addition, the first plasma can be formed by applying a very high frequency (VHF) power source and a low frequency (LF) power source. In addition, the first plasma can also be formed by applying a very high frequency (VHF) power source and a high frequency (HF) power source. In particular, the first plasma can be formed by applying at least one of a very high frequency (VHF) power source and a high frequency (HF) power source and a low frequency (LF) power source.

[0037] In one embodiment, in this step, hydrogen (H2) gas is supplied to the upper portion of the metal nitride thin film. Then, a low-frequency (LF) power of 460 kHz or less and a high-frequency (HF) power of 13.56 MHz are simultaneously applied to form a first plasma. In addition, the first plasma is used to perform a first surface treatment on the metal nitride thin film for 0.01 to 60 seconds.

[0038] In addition, in this step, it can be configured to perform the first surface treatment n times (wherein n means a natural number greater than or equal to 1). Specifically, the process of supplying a hydrogen-containing gas to the process chamber and forming a first plasma to perform the first surface treatment on the metal nitride thin film for a certain period of time can be performed at least once. By repeatedly performing the first surface treatment, residual gases of the metal precursor, residual ions in the film, and the concentration and particles of contaminants can be removed more efficiently.

[0039] Next, in the second surface treatment step (S400), a nitrogen-containing gas is supplied to the process chamber (110) and a second plasma is formed to subject the first surface-treated substrate to a second surface treatment.

[0040] In this step, the metal nitride thin film that has been surface-treated first is subjected to nitriding treatment through a second surface treatment method using a second plasma, thereby reducing the stress of the metal nitride thin film, preventing cracks from occurring, and lowering the surface resistance.

[0041] Specifically, in this step, a nitrogen-containing gas, which is a reaction gas, is supplied to the upper portion of the first surface-treated metal nitride thin film, and a second plasma is formed. In particular, in this step, hydrogen gas may be supplied together with the nitrogen-containing gas to further enhance the second surface treatment effect. More specifically, ionized nitrogen ions are formed from the nitrogen-containing gas by the second plasma. The first surface-treated metal nitride thin film is exposed to the second plasma, so that metal precursor ions, impurities contained in the metal precursor, and hydrogen contained in the reaction gas are ionized on the surface. The ionized metal precursor ions and nitrogen ions combine to form a film texture of the metal nitride thin film. In addition, the ionized residual impurity ions and ionized hydrogen combine to be detached and removed from the surface of the metal nitride thin film. Accordingly, the second plasma treatment can reduce the stress of the metal nitride thin film, prevent cracking of the metal nitride thin film, and lower the surface resistance of the metal nitride thin film.

[0042] In addition, in this step, the second surface treatment can be performed by continuously supplying argon gas together with the reaction gas.

[0043] Additionally, in this step, the metal nitride thin film can be nitrided by forming the second plasma by applying at least one of low-frequency power, high-frequency power, and ultra-high-frequency power.

[0044] According to one embodiment, in this step, the second plasma can be formed by applying a dual frequency power source. Specifically, the second plasma can be formed by applying a high frequency (HF) power source and a low frequency (LF) power source. The second plasma can be formed by applying a very high frequency (VHF) power source and a low frequency (LF) power source. That is, the second plasma can be formed by applying a dual frequency power source that applies either a very high frequency (VHF) power source and a high frequency (HF) power source and a low frequency (LF) power source. In addition, the second plasma can be formed by applying at least one of a very high frequency power source and a high frequency power source and a low frequency power source.

[0045] In particular, in this step, a second plasma can be formed by applying a high-frequency (HF) power source and a low-frequency (LF) power source. This is because the film properties can be further improved when considering the plasma energy and density, which are the characteristics of the high-frequency (HF) power source and the low-frequency (LF) power source, respectively.

[0046] According to one embodiment, in this step, a nitrogen-containing gas is supplied to the upper portion of the metal nitride thin film, a low-frequency power of 460 kHz or less and a high-frequency power of 13.56 MHz are simultaneously applied, and the metal nitride thin film is subjected to a second surface treatment for 0.01 to 60 seconds.

[0047] In addition, in this step, a nitrogen-containing gas may be supplied and a second plasma may be formed to perform surface treatment on the first surface-treated substrate m times (wherein m represents a natural number greater than or equal to 1). By repeatedly performing the second surface treatment step (S400) as described above, the stress reduction efficiency can be further improved, thereby further improving film cracks and surface resistance.

[0048] In the method for forming a metal nitride thin film according to the above-described embodiment, the properties of the metal nitride thin film can be further improved by forming the first plasma and the second plasma using a dual-frequency power source.

[0049] Specifically, in performing the thin film deposition and surface treatment processes using the first and second plasmas, respectively, one of the particles that directly plays a role is an ion. The ion affects the electrical, chemical, and physical properties of the thin film to be deposited, depending on its ion energy characteristics.

[0050] Fig. 3 is a graph showing the ion energy distribution and ion energy intensity (unit: eV) by frequency to explain the ion energy formed by plasma in the method for forming a metal nitride thin film according to an embodiment. Fig. 4 is a graph showing a superimposed wave by time and voltage formed by a dual frequency power source in the method for forming a metal nitride thin film according to an embodiment. Fig. 5 is a graph showing a change in ion energy distribution when a dual frequency power source is applied in the method for forming a metal nitride thin film according to an embodiment.

[0051] Typically, when a single-frequency power source is used to form a plasma, the ion energy distribution exhibits a monomodal or bimodal peak. At this time, the ion energy distribution exhibits different modal peaks depending on the difference between the ion transit time and the operating frequency. Furthermore, the sheath electrodes also change simultaneously depending on the operating frequency of the power source used to form the plasma.

[0052] Regarding the above dual frequencies, capacitively coupled plasma (CCP) cannot control ion energy while maintaining constant density characteristics. The capacitively coupled plasma can control plasma density and ion energy using power sources of different frequencies. Typically, a low frequency power source exhibits high ion energy at low density. A high frequency power source exhibits low ion energy at high density. A type that applies two different frequencies to one electrode is called a superimposed electrode, and the two frequency power sources are superimposed to exhibit a superimposed frequency (see Fig. 4).

[0053] Referring to Fig. 5, when a dual plasma is formed using power sources of different frequencies, as a high frequency is applied to the low frequency plasma, the plasma density increases, the thickness of the plasma sheath decreases, and the overall ion energy distribution shifts toward the lower side (see Figs. 5(a) and 5(b)).

[0054] Additionally, when the power of the high-frequency power source increases in dual frequencies, the ion energy distribution shifts toward lower energy. Conversely, when the power of the low-frequency power source increases in dual frequencies, the ion energy distribution shifts toward higher energy.

[0055] Accordingly, the dual frequency power source applies two different frequencies and converts them into a superposition state. The dual frequency power source can form an appropriate ion energy compared to the case where a single frequency is used, and induce a deposition reaction while appropriately controlling the density. In addition, the characteristics of different frequency bands can all be applied by controlling the power. When the dual frequency power source is used, the removal of metal precursor gas, reduction in the concentration of residual ions and contaminants in the film, and particle removal effects can be improved compared to the case where the first plasma is formed using a single frequency power source. In addition, when the dual frequency power source is used, the nitriding treatment effect is improved compared to the case where the second plasma is formed using a single frequency power source, so that the stress of the film can be further improved, and crack occurrence can be more effectively prevented, thereby improving the physical properties of the thin film.

[0056] In the method for forming a metal nitride thin film according to the above-described embodiment, the metal nitride thin film deposited by the thermal chemical vapor deposition method is subjected to a first surface treatment using hydrogen plasma to remove a metal precursor gas having a slow flow rate. Accordingly, the concentration of residual ions and contaminants in the film quality of the metal nitride thin film can be reduced and the level of particles can be improved. In addition, by subjecting the metal nitride thin film subjected to the first surface treatment to a second nitriding treatment using plasma, the stress on the film quality can be reduced, crack occurrence can be prevented, and surface resistance can be lowered. Accordingly, a metal nitride thin film having improved electrical, chemical, and physical properties can be formed.

[0057]

[0058] Meanwhile, in the method for forming a metal nitride film according to an embodiment, a metal nitride thin film can be formed using a substrate processing device having a variety of structures commonly used for performing a plasma-enhanced chemical vapor deposition method. For example, in the method for forming a metal nitride film according to an embodiment, a metal nitride film can be formed on a substrate using the following substrate processing device.

[0059] Fig. 6 is a schematic diagram showing a substrate processing device according to one embodiment.

[0060] Referring to FIG. 6, a substrate processing device (100) according to one embodiment may have a structure including a process chamber (110), a gas injection unit (120), a substrate mounting unit (130), and a plasma power supply unit (140) as basic components.

[0061] The above process chamber (110) may define a processing space (112) therein. For example, the process chamber (110) is configured to maintain airtightness, and may be connected to a vacuum chamber (not shown) through an exhaust port to discharge process gases within the processing space (112) and control the vacuum level within the processing space (112). The process chamber (110) may have various shapes. For example, the process chamber (110) may have a structure including a side wall portion defining the processing space (112) and a cover portion positioned on an upper portion of the side wall portion.

[0062] The gas injection unit (120) may be installed in the process chamber (110) to supply the process gas supplied from the outside of the process chamber (110) to the processing space (112). The gas injection unit (120) may be installed at the top of the process chamber (110) against the substrate mounting unit (13) to inject the process gas onto the substrate (S) mounted on the substrate mounting unit (130). The gas injection unit (120) may include at least one inlet hole formed at the top or side to receive the process gas from the outside, and a plurality of injection holes formed downward facing the substrate (S) to inject the process gas onto the substrate (S). For example, the gas injection unit (120) may have various shapes, such as a shower head shape or a nozzle shape. When the above gas injection unit (120) is in the form of a shower head, the gas injection unit (120) may be coupled to the process chamber (110) in a form that covers the upper portion of the process chamber (110). For example, the gas injection unit (120) may be coupled to the side wall in the form of a cover of the process chamber (110).

[0063] The substrate mounting portion (130) is installed in the process chamber (110) facing the gas injection portion (120), and a substrate (S) can be mounted thereon. The substrate mounting portion (130) may have a structure corresponding to the shape of the substrate. The substrate mounting portion (130) may include a heater (131) for heating the substrate (S), and may include a heater power supply for supplying power to the heater (131). In addition, the substrate mounting portion (130) may heat the substrate by applying power to the heater (131). The substrate mounting portion (130) may be connected to an external motor to form a structure capable of being raised and lowered, and may also be called a substrate support, a susceptor, etc.

[0064] The plasma power supply unit (140) may include at least one radio frequency (RF) power source to apply at least one RF power source to the process chamber (110) to form a plasma atmosphere inside the process chamber (110). For example, the plasma power supply unit (140) may be connected to apply RF power to the gas injection unit (120). In this case, the gas injection unit (120) may also be referred to as a power supply electrode or an upper electrode. The impedance matching unit (146) may be disposed between the plasma power supply unit (140) and the gas injection unit (120) to match impedance between the RF power source and the process chamber (110).

[0065] The RF power supply unit (140) may have one or more RF power sources. For example, the RF power source may include multiple RF power sources with different frequency bands to control the plasma environment according to process conditions. The dual frequency power source composed of the first RF power source (142) and the second RF power source (144) has the advantage of being able to precisely control the process because the frequency band can be varied according to process conditions or process steps. In the drawing, the power source of the plasma power supply unit (140) is illustrated as two RF power sources (142, 144), but this is exemplary and the scope of the present invention is not limited thereto.

[0066] Specifically, the plasma power supply unit (140) can apply low frequency, high frequency, and very high frequency RF power, respectively, including at least one of low frequency (LF) power in a frequency range of 100 kHz to 5 MHz, high frequency (HF) power in a frequency range of 5 to 30 MHz, and very high frequency (VHF) power in a frequency range of 30 to 80 MHz.

[0067] In addition, the substrate processing device according to the embodiment may include a filter, a current control circuit, etc. for impedance adjustment, current control, etc., but is not limited thereto.

[0068]

[0069] Hereinafter, the present invention will be described in more detail by way of examples.

[0070] The presented examples are only specific examples of the present invention and are not intended to limit the technical configuration of the present invention.

[0071] <Example 1>

[0072] The substrate was placed within the processing chamber's processing space. Titanium tetrachloride gas and ammonia gas were respectively supplied into the processing space. Furthermore, a titanium nitride thin film was formed on top of the substrate using a thermal CVD process at 650°C. A purge step was then performed to remove any unreacted gases.

[0073] Next, hydrogen (H2) gas was supplied to the upper portion of the titanium nitride thin film. Then, a low-frequency power of 450 kHz was applied at a power of 450 W to form a first plasma. The titanium nitride thin film was surface-treated for 10 seconds with hydrogen plasma containing hydrogen ions activated by the first plasma.

[0074] Then, ammonia (NH3) gas and hydrogen (H2) gas were supplied to the upper part of the first surface-treated titanium nitride thin film, respectively. In addition, a low-frequency power of 450 kHz was applied at a power of 450 W to form a second plasma. The titanium nitride thin film was nitrided for 30 seconds with nitrogen plasma containing nitrogen ions activated by the second plasma. Accordingly, a titanium nitride thin film having a thickness of 802 Å was formed on the upper part of the substrate. At this time, the hydrogen plasma treatment and the second plasma treatment were each performed once.

[0075] <Example 2>

[0076] A first plasma was formed by applying a high-frequency power of 13.56 MHz at a power of 450 W to surface-treat a titanium nitride thin film. Next, a second plasma was formed by applying a high-frequency power of 13.56 MHz at a power of 450 W to nitride the titanium nitride thin film that had been surface-treated with hydrogen plasma. Except for these, a titanium nitride thin film was formed in the same manner as in Example 1. Accordingly, the formed titanium nitride thin film was confirmed to have a thickness of 788 Å.

[0077] <Example 3>

[0078] A titanium nitride thin film was formed in the same manner as in Example 1, except that a low-frequency power of 450 kHz and a high-frequency power of 13.56 MHz were applied at a power of 450 W each to form a first plasma and a second plasma, respectively, for surface treatment. Accordingly, the formed titanium nitride thin film was confirmed to have a thickness of 793 Å.

[0079] <Comparative Example>

[0080] A titanium nitride thin film was formed on the upper surface of the substrate by a thermal CVD process by supplying titanium tetrachloride gas and ammonia gas, respectively, in the same manner as in Example 1, except that the surface was not treated with the first plasma and the second plasma. Accordingly, the formed titanium nitride thin film was confirmed to have a thickness of 796 Å.

[0081]

[0082] <Experimental Example>

[0083] (1) Evaluation of the impact of hydrogen plasma treatment

[0084] In order to evaluate the effect of hydrogen plasma treatment, the chloride ion concentration of the thin films formed by the methods according to Examples 1 to 3 was evaluated using secondary ion mass spectrometry (SIMS), and the results are shown in Fig. 7. At this time, the thin films not treated with hydrogen plasma were also evaluated as an untreated control.

[0085] As shown in Fig. 7, it was confirmed that the concentration of chloride ions was reduced by hydrogen plasma treatment, and in particular, it was confirmed that the use of dual plasma was most effective in removing residual chloride ions.

[0086] (2) Evaluation of the impact of surface nitriding treatment 1

[0087] In order to evaluate the effect of surface nitriding treatment on resistance, the thickness (unit: Å), stress (unit: MPa), average sheet resistance (Rs avg., unit: Ω / □), and sheet resistance uniformity (Rs Unif., unit: %) of thin films formed by the methods according to the examples and comparative examples were evaluated, and the results are shown in Table 1 below.

[0088]

[0089] As shown in Table 1, it was confirmed that when the methods according to the examples and comparative examples were used in the process of forming a titanium nitride thin film with a target thickness of 800 Å, thin films without significant deviation were formed.

[0090] In addition, it was confirmed that the film stress was reduced by more than 32% compared to the untreated control group (comparative example) by surface nitriding treatment, and in particular, it was confirmed that it was reduced by more than 48% when treated with dual plasma.

[0091] In addition, as a result of checking the average sheet resistance and sheet resistance uniformity of each thin film, it was confirmed that the resistance characteristics were significantly improved by dual frequency plasma treatment, and it was confirmed that the physical properties could be improved even when HF power was applied.

[0092] (3) Evaluation of the impact of surface nitriding treatment 2

[0093] In order to evaluate the effect of plasma nitriding treatment on the formation of cracks in thin films, the film quality of thin films formed by the methods according to the examples and comparative examples was evaluated using an electron microscope, and the results are shown in Fig. 8.

[0094] As shown in Fig. 8(b), Fig. 8(c), and Fig. 8(d), no cracks occurred in any of the plasma-treated cases. However, as shown in Fig. 8(a), cracks occurred only in the comparative example that was not plasma-treated, and these results confirmed that plasma nitriding treatment can prevent cracks in thin films.

[0095] Through the above results, it was confirmed that when the metal nitride thin film forming method according to the embodiment is used, cracks do not easily occur even when forming a thick metal nitride thin film, and a metal nitride thin film having excellent electrical properties due to low resistance and low residue concentration can be formed.

[0096] [Explanation of symbols]

[0097] 100: Substrate processing device

[0098] 110: Process chamber

[0099] 120: Gas injection unit

[0100] 130: Substrate mounting area

[0101] 140: Plasma power supply

[0102] S: substrate

Claims

1. A substrate preparation step in which a substrate is prepared into a process chamber in which a processing space is formed; A thin film forming step of forming a metal nitride thin film on the upper part of the substrate by supplying a metal precursor gas and a nitrogen-containing gas, respectively; A first surface treatment step of supplying a hydrogen-containing gas to the process chamber and forming a first plasma to surface-treat the metal nitride thin film at least once; and A method for forming a metal nitride thin film, comprising: a second surface treatment step of supplying a nitrogen-containing gas to the process chamber and forming a second plasma to treat the surface of the first surface-treated substrate at least once; 2. In paragraph 1, The above thin film forming step is: A method for forming a metal nitride thin film, characterized in that the metal nitride thin film is formed by reacting the metal precursor gas and the nitrogen-containing gas using a thermal chemical vapor deposition (thermal CVD) method performed at a temperature of 300 to 800°C.

3. In paragraph 1, A method for forming a metal nitride thin film, wherein the metal nitride thin film comprises any one of titanium nitride (TiN), tungsten nitride (WN), molybdenum nitride (Mo2N), tantalum nitride (TaN), aluminum nitride (AlN), and titanium aluminum nitride (TiAlN).

4. In paragraph 1, A method for forming a metal nitride thin film, wherein the metal precursor gas comprises at least one metal precursor selected from the group consisting of titanium tetrachloride (TiCl4), tetrakis dimethylamino titanium (TDMAT, Ti(N(Me2)4)), tetrakis diethylamino titanium (TDEAT, Ti(N(Et2)4)), and tetrakis ethylmethylamino titanium (TEMAT, Ti(N(EtMe)4)).

5. In paragraph 1, A method for forming a metal nitride thin film, wherein the above nitrogen-containing gas includes at least one of ammonia (NH3) gas and nitrogen (N2) gas.

6. In paragraph 1, The above first surface treatment step is, A method for forming a metal nitride thin film, characterized in that the first plasma is formed by applying a dual frequency power source.

7. In paragraph 6, A method for forming a metal nitride thin film, characterized in that the first plasma is formed by applying at least one of high frequency or ultra-high frequency and low frequency.

8. In paragraph 1, The second surface treatment step is: A method for forming a metal nitride thin film, characterized in that the second plasma is formed by applying a dual frequency power source.

9. In paragraph 8, A method for forming a metal nitride thin film, characterized in that the second plasma is formed by applying at least one of high frequency (HF) or very high frequency (VHF) and low frequency (LF).

10. In paragraph 1, The second surface treatment step is: A method for forming a metal nitride thin film, characterized by further supplying a hydrogen-containing gas.

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