Method for forming metal nitride thin films

Abstract

A method for forming a metal nitride thin film is provided. [Solution] A method for forming a metal nitride thin film according to an embodiment includes a substrate preparation step of preparing a substrate in a process chamber having a processing space formed therein; a thin film formation step of supplying a metal precursor gas and a nitrogen-containing gas, respectively, to form a metal nitride thin film on the substrate; a first surface treatment step of supplying a hydrogen-containing gas to the process chamber, forming a first plasma, and performing at least one surface treatment on the metal nitride thin film; and a second surface treatment step of supplying a nitrogen-containing gas to the process chamber, forming a second plasma, and performing at least one surface treatment on the substrate that has undergone the first surface treatment.

Description

Technical Field

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

[0002] Recently, along with the miniaturization and high integration of semiconductor devices, there has been an increasing demand for a method capable of reducing the number and size of particles and improving film quality. Particularly in the case of metal nitride thin films such as titanium nitride thin films, more importance is placed on the control of film quality and yield.

[0003] Generally, a metal nitride thin film is formed using chemical vapor deposition (CVD), in which a metal source gas and a nitrogen-containing gas are supplied into a reaction chamber and caused to react thermally to form a thin film on a substrate. Immediately after depositing the metal nitride thin film, hydrogen plasma is used to remove metal precursor residues having a low flow rate, thereby improving the levels of residues and particles in the film quality.

[0004] However, when a thick metal nitride thin film is formed by the above-mentioned conventional method, cracks are likely to occur in the thin film due to high stress, and there is a risk of forming a film with high resistance. Therefore, research on a method that can compensate for this is needed. Summary of the Invention Problem to be Solved by the Invention

[0005] According to one embodiment, provided is a technical content relating to a method for forming a metal nitride thin film, which can form a thin film of low stress and low resistance even when forming a thick metal nitride thin film, and can prevent the occurrence of defects such as cracks. Means for Solving the Problem

[0006] In the method for forming a metal nitride thin film according to the embodiment, the process includes a substrate preparation step of preparing a substrate in a process chamber in which a processing space is formed, a thin film formation step of supplying a metal precursor gas and a nitrogen-containing gas, respectively, to form a metal nitride thin film on the substrate, and supplying a hydrogen-containing gas to the process chamber to form a first plasma and form the metal nitride thin film. multiple times A first surface treatment step involves surface treatment, and a second plasma is formed by supplying nitrogen-containing gas to the process chamber and then processing the substrate that has undergone the first surface treatment. multiple times The process includes a second surface treatment step of surface treatment.

[0007] According to one embodiment, the thin film formation step of forming a metal nitride thin film on a substrate can be performed by a thermochemical vaporized position (thermal CVD) method carried out at a temperature of 300 to 800°C, in which a metal precursor gas and a nitrogen-containing gas are reacted to form a 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] According to one example, the metal precursor gas may contain any one of the following metal precursors: 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] According to one embodiment, the nitrogen-containing gas may include at least one of ammonia (NH3) gas and nitrogen (N2) gas.

[0011] According to one embodiment, the first surface treatment step and the second surface treatment step can each be performed by applying a dual-frequency power supply to form a first plasma and a second plasma, respectively. In particular, the first plasma and the second plasma can be formed by applying at least one high frequency or ultra-high frequency and a low frequency.

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

[0013] In the method for forming a metal nitride thin film according to the embodiment, a metal nitride thin film deposited by thermochemical vapor deposition (thermal CVD) is subjected to a first surface treatment using hydrogen plasma to remove slow-flowing metal precursor gases. The first surface treatment step reduces the concentration of residual ions and contaminants within the film quality of the metal nitride thin film, thereby improving the particle level. Furthermore, the metal nitride thin film that has undergone the first surface treatment is subjected to a second surface treatment using a second plasma. The second surface treatment step reduces stress on the film quality, prevents crack formation, and lowers the surface resistance. As a result, the method for forming a metal nitride thin film according to the embodiment can form a metal nitride thin film with improved electrical, chemical, and physical properties. [Brief explanation of the drawing]

[0014] [Figure 1] This is a process diagram showing a method for forming a metal nitride thin film according to an example. [Figure 2] This is a timing diagram showing the method for forming a metal nitride thin film according to the example. [Figure 3] This graph shows the ion energy distribution and ion energy intensity by frequency to explain the ion energy formed by the plasma in the metal nitride thin film formation method according to the example. [Figure 4]This graph shows the superimposed waveforms at different voltages and times, formed by a dual-frequency power supply in the metal nitride thin film formation method according to the embodiment. [Figure 5] This graph shows the change in ion energy distribution when a dual-frequency power supply is applied in the metal nitride thin film formation method according to the embodiment. [Figure 6] This is a configuration diagram showing a substrate processing apparatus according to one embodiment. [Figure 7] This is SIMS data showing the results of evaluating the chloride ion concentration of thin films formed by the methods described in Examples 1 to 3. [Figure 8] (a) Comparative Example, (b) Example 1, (c) Example 2, and (d) Electron microscope images of the surface of a thin film formed by the method described in Example 3. [Modes for carrying out the invention]

[0015] Figure 1 is a process diagram showing a method for forming a metal nitride thin film according to an example. Figure 2 is a timing diagram showing an example of a method for forming a metal nitride thin film according to an example.

[0016] Referring to Figures 1 and 2, the method for forming a metal nitride thin film according to the embodiment includes a substrate preparation step (S100) of preparing a substrate (S) in a process chamber 110 in which a processing space is formed, a thin film formation step (S200) of forming a metal nitride thin film on the substrate (S), a first surface treatment step (S300) of surface treating the metal nitride thin film, and a second surface treatment step (S400) of surface treating the substrate (S) that has undergone the first surface treatment. The method for forming a metal nitride thin film according to the embodiment can be carried out using various types of conventional substrate processing equipment used to form a metal nitride thin film on a substrate (S). Furthermore, the substrate processing equipment may be one used to carry out a plasma-enhanced chemical vapor deposition process.

[0017] First, in the substrate preparation step (S100), the substrate (S) is placed on the substrate mounting section 130 installed in the processing space of the process chamber.

[0018] The substrate (S) may be any of various conventional substrates used for manufacturing semiconductor devices by forming a metal nitride thin film on an upper portion thereof.

[0019] Next, in the thin film forming step (S200), a metal precursor gas and a nitrogen-containing gas are each supplied onto the substrate (S) to form a metal nitride thin film on the substrate (S).

[0020] In this step, the metal nitride thin film can be formed by respectively supplying a metal precursor gas and a nitrogen-containing gas and reacting these gases with each other. In this step, the metal nitride thin film can be formed by reacting the metal precursor gas and the nitrogen-containing gas through a thermal chemical vapor deposition method performed at a temperature of 300 to 800°C. In particular, this step can be performed at a temperature of 500 to 700°C.

[0021] The 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).

[0022] As the metal precursor gas, any of various conventional metal precursor gases utilized for forming a metal nitride thin film can be supplied.

[0023] In particular, the metal nitride thin film may be a titanium nitride thin film. Accordingly, 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)).

[0024] The nitrogen-containing gas may include at least one of ammonia (NH₃) gas and nitrogen (N₂) gas.

[0025] When forming a metal nitride thin film by thermochemical vapor deposition, the metal nitride thin film is prone to cracking under high stress, potentially resulting in a film with high resistance. In the metal nitride thin film formation method according to the example, a PECVD process is introduced in which the metal nitride thin film is surface-treated using a first plasma and a second plasma, respectively, to enable the formation of a metal nitride thin film with excellent physical properties.

[0026] Next, in the first surface treatment step (S300), a hydrogen-containing gas is supplied to the process chamber 110 to form a first plasma, and the metal nitride thin film can be subjected to the first surface treatment.

[0027] In this step, a hydrogen-containing gas is supplied to form a first plasma and perform a first surface treatment on the metal nitride thin film. The first surface treatment removes slow-flowing residual metal precursor gas, reduces the concentration of residual ions and contaminants within the film quality of the metal nitride thin film, and improves the particle level. The hydrogen-containing gas may be hydrogen (H2) gas.

[0028] In this step, a first plasma can be formed by applying at least one of a low-frequency (LF) power supply, a high-frequency (HF) power supply, and a very high-frequency (VHF) power supply to perform a first surface treatment on a metal nitride thin film.

[0029] According to one embodiment, in this step, a first plasma can be formed by applying a dual-frequency power supply. The first plasma can be formed by applying a high-frequency (HF) power supply and a low-frequency (LF) power supply. Alternatively, the first plasma can be formed by applying a very high-frequency (VHF) power supply and a low-frequency (LF) power supply. Furthermore, the first plasma can be formed by applying a very high-frequency (VHF) power supply and a high-frequency (HF) power supply. In particular, the first plasma can be formed by applying a very high-frequency (VHF) power supply, one of the high-frequency (HF) power supplies, and a low-frequency (LF) power supply.

[0030] In one embodiment, in this step, hydrogen (H2) gas is supplied onto a metal nitride thin film. Then, a low-frequency (LF) power supply of 460 kHz or less and a high-frequency (HF) power supply of 13.56 MHz are simultaneously applied to form a first plasma. Furthermore, the metal nitride thin film is subjected to a first surface treatment using the first plasma for a period of 0.01 to 60 seconds.

[0031] Furthermore, this step can be configured to perform the first surface treatment n times (where n is a natural number greater than or equal to 1). Specifically, a hydrogen-containing gas can be supplied to the process chamber to form a first plasma, and the metal nitride thin film can be subjected to the first surface treatment at least once within a certain time. By repeating the first surface treatment, residual metal precursor gas, residual ions in the film, contaminants, and particles can be efficiently removed.

[0032] Next, in the second surface treatment step (S400), nitrogen-containing gas is supplied to the process chamber 110 to form a second plasma, and the substrate that has undergone the first surface treatment is subjected to the second surface treatment.

[0033] In this step, the metal nitride thin film that has undergone the first surface treatment is nitrided using the second surface treatment method with the second plasma, thereby reducing stress on the metal nitride thin film, preventing crack formation, and lowering the surface resistance.

[0034] Specifically, in this step, a nitrogen-containing gas, which is a reaction gas, is supplied onto the first surface-treated metal nitride thin film to form a second plasma. In particular, in this step, the effect of the second surface treatment can be further improved by supplying hydrogen gas together with the nitrogen-containing gas. More specifically, 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, and 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 the film quality of the metal nitride thin film. In addition, ionized residual impurity ions and ionized hydrogen combine and are removed from the surface of the metal nitride thin film. As a result, the second plasma treatment not only reduces stress on the metal nitride thin film and prevents the occurrence of cracks in the metal nitride thin film, but also reduces the surface resistance of the metal nitride thin film.

[0035] In addition, this step can be carried out by continuously supplying argon gas along with the reaction gas for the second surface treatment.

[0036] Furthermore, in this step, a second plasma can be formed by applying at least one of a low-frequency power supply, a high-frequency power supply, and an ultra-high-frequency power supply, thereby performing a nitriding treatment on the metal nitride thin film.

[0037] According to one embodiment, in this step, a second plasma can be formed by applying a dual-frequency power supply. Specifically, the second plasma can be formed by applying a high-frequency (HF) power supply and a low-frequency (LF) power supply. The second plasma can be formed by applying a very high-frequency (VHF) power supply and a low-frequency (LF) power supply. That is, the second plasma can be formed by applying a dual-frequency power supply that applies either a very high-frequency (VHF) power supply or a high-frequency (HF) power supply and a low-frequency (LF) power supply. Alternatively, it can be formed by applying at least one of a very high-frequency power supply and a high-frequency power supply and a low-frequency power supply.

[0038] In particular, in this step, a second plasma can be formed by applying a high-frequency (HF) power supply and a low-frequency (LF) power supply. This is because, considering the plasma energy and density, which are the respective characteristics of the high-frequency (HF) power supply and the low-frequency (LF) power supply, the physical properties of the film can be further improved.

[0039] According to one embodiment, in this step, a nitrogen-containing gas is supplied onto the metal nitride thin film, and a low-frequency power supply of 460 kHz or less and a high-frequency power supply of 13.56 MHz are simultaneously applied to perform a second surface treatment on the metal nitride thin film for 0.01 to 50 seconds.

[0040] Furthermore, in this step, a nitrogen-containing gas is supplied to form a second plasma, and the substrate that has undergone the first surface treatment is configured to be surface-treated m times (where m is a natural number greater than or equal to 1). As mentioned above, by repeating the second surface treatment step (S400), the efficiency of stress reduction can be further improved, thereby further improving the crack resistance of the film and the surface resistance.

[0041] As described above, in the method for forming a metal nitride thin film according to the embodiment, the physical properties of the metal nitride thin film can be further improved by utilizing a dual-frequency power supply to form a first plasma and a second plasma, respectively.

[0042] Specifically, ions are one of the particles that play a direct role in carrying out thin film deposition and surface treatment processes using the first and second plasmas, respectively. Ions influence the electrical, chemical, and physical properties of the deposited thin film through their ionic energy characteristics.

[0043] Figure 3 is a graph showing the frequency-specific ion energy distribution and ion energy intensity (unit: eV) to explain the ion energy formed by the plasma in the metal nitride thin film formation method according to the embodiment. Figure 4 is a graph showing the superimposed wave with respect to voltage and time formed by a dual-frequency power supply in the metal nitride thin film formation method according to the embodiment. Figure 5 is a graph showing the change in ion energy distribution when a dual-frequency power supply is applied in the metal nitride thin film formation method according to the embodiment.

[0044] Generally, when a plasma is formed using a single-frequency power supply, the ion energy distribution will exhibit either a mono-modal or bi-modal peak. In this case, the ion energy distribution will show different modal peaks depending on the difference in ion transit time and operating frequency. Furthermore, the sheath electrodes will also change simultaneously depending on the operating frequency of the power supply used for plasma formation.

[0045] When examining dual frequencies, it becomes clear that capacitively coupled plasma (CCP) cannot adjust ion energy while maintaining a constant density characteristic. Capacitively coupled plasmas, however, can have their plasma density and ion energy adjusted using power sources of different frequencies. Typically, low-frequency power sources result in low density and high ion energy, while high-frequency power sources result in high density and low ion energy. A type where two different frequencies are applied to a single electrode is called a superimposed electrode, where the two frequency power sources are superimposed, resulting in a superimposed frequency (see Figure 4).

[0046] As shown in Figure 5, when dual plasmas are formed using power supplies of different frequencies, applying a high frequency to the low-frequency plasma increases the plasma density and decreases the thickness of the plasma sheath, resulting in an overall shift in the ion energy distribution towards the lower end (see Figures 5(a) and 5(b)).

[0047] Furthermore, in a dual-frequency system, when the power of the high-frequency power supply increases, the ion energy distribution shifts towards lower energies. Conversely, in a dual-frequency system, when the power of the low-frequency power supply increases, the ion energy distribution shifts towards higher energies.

[0048] This allows a dual-frequency power supply to apply two different frequencies and convert them into a superimposed state. Compared to using a single-frequency power supply, a dual-frequency power supply can create appropriate ion energy and induce the deposition reaction with properly adjusted density. Furthermore, the characteristics of different frequency bands can all be applied by adjusting the power. When using a dual-frequency power supply, compared to using a single-frequency power supply to form the first plasma, metal precursor gas removal, reduction of residual ions and contaminants in the film, and particle removal can be performed more efficiently. In addition, when using a dual-frequency power supply, compared to using a single-frequency power supply to form the second plasma, the nitriding effect can be improved, reducing stress on the film, preventing crack formation, and improving the physical properties of the thin film.

[0049] As described above, in the method for forming a metal nitride thin film according to the embodiment, the slow-flowing metal precursor gas can be removed by performing a first surface treatment using hydrogen plasma on a metal nitride thin film deposited by thermochemical vapor deposition. This reduces the concentration of residual ions and contaminants within the film quality of the metal nitride thin film, improving the particle level. Furthermore, by performing a nitriding treatment on the metal nitride thin film that has undergone the first surface treatment using a second plasma, stress on the film quality is reduced, preventing crack formation and lowering the surface resistance. This makes it possible to form a metal nitride thin film with improved electrical, chemical, and physical properties.

[0050] On the other hand, in the metal nitride thin film formation method according to the embodiment, metal nitride thin films can be formed using various substrate processing apparatuses with common structures used to carry out plasma-enhanced chemical vapor deposition. For example, in the metal nitride thin film formation method according to the embodiment, metal nitride thin films can be formed on a substrate using the following substrate processing apparatus.

[0051] Figure 6 is a configuration diagram showing a substrate processing apparatus according to one embodiment.

[0052] Referring to Figure 6, the substrate processing apparatus 100 according to one embodiment may have a structure that includes a process chamber 110, a gas injection unit 120, a substrate mounting unit 130, and a plasma power supply unit 140 as its basic components.

[0053] The process chamber 110 can confine a processing space 112 within it. For example, the process chamber 110 may be configured to maintain airtightness and may be connected to a vacuum chamber (not shown) through an exhaust port to vent process gases from the processing space 112 and adjust the vacuum level within the processing space 112. The process chamber 110 can have a variety of shapes. As an example, the process chamber 110 may have a structure that includes side walls that confine the processing space 112 and a cover located above the side walls.

[0054] The gas injection unit 120 may be installed in the process chamber 110 so that process gas supplied from outside the process chamber 110 is supplied to the processing space 112. The gas injection unit 120 may be installed on top of the process chamber 110, facing the substrate mounting section 130, to inject process gas onto a substrate (S) placed on the substrate mounting section 130. The gas injection unit 120 may include at least one inlet hole formed on the top or side so that process gas is supplied from the outside, and a plurality of injection holes formed downward toward the substrate (S) so that process gas is injected onto the substrate (S). For example, the gas injection unit 120 can have various forms, such as a shower head form or a nozzle form. If the 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 manner that covers the top of the process chamber 110. For example, the gas injection unit 120 may be coupled to the side wall of the process chamber 110 in a cover form.

[0055] The substrate mounting section 130 is installed in the process chamber 110 so as to face the gas injection section 120, and a substrate (S) can be placed on it. The substrate mounting section 130 may have a structure that corresponds to the shape of the substrate. The substrate mounting section 130 may include a heater 131 for heating the substrate (S), and may include a heater power supply unit for supplying power to the heater 131. The substrate mounting section 130 can also heat the substrate by applying power to the heater 131. The substrate mounting section 130 can be connected to an external motor to form a structure that can be raised and lowered, and may also be referred to as a substrate support stand or susceptor.

[0056] The plasma power supply unit 140 may include at least one RF power supply so as to apply at least one RF (radio frequency) power to the process chamber 110 in order to form a plasma atmosphere within the process chamber 110. For example, the plasma power supply unit 140 may be connected so as 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 upper electrode. An impedance matching unit 146 may be located between the plasma power supply unit 140 and the gas injection unit 120 for impedance matching between the RF power supply and the process chamber 110.

[0057] The RF power supply in the plasma power supply unit 140 may consist of one or more RF power supplies. For example, the RF power supply may include multiple RF power supplies with different frequency bands for controlling the plasma environment according to process conditions. A dual-frequency power supply consisting of a first RF power supply 142 and a second RF power supply 144 has the advantage of allowing precise control of the process by using different frequency bands according to process conditions or process steps. The figure shows a plasma power supply unit 140 with two RF power supplies 142 and 144, but this is merely an illustration and the scope of the present invention is not limited thereto.

[0058] Specifically, the plasma power supply unit 140 includes at least one of the following: a low-frequency (LF) power supply in the 100kHz to 5MHz frequency range, a high-frequency (HF) power supply in the 5 to 30MHz frequency range, and a very high-frequency (VHF) power supply in the 30 to 80MHz frequency range, and can apply low-frequency, high-frequency, and very high-frequency RF power supplies, respectively.

[0059] Furthermore, the substrate processing apparatus according to the embodiment may include, but is not limited to, filters, current control circuits, etc., for purposes such as impedance adjustment and current control.

[0060] The present invention will be described in more detail below based on examples and other relevant information.

[0061] The examples provided are merely illustrative of the present invention and do not limit the technical configuration of the present invention.

[0062] <Example 1> The substrate was placed in the processing chamber. Titanium tetrachloride gas and ammonia gas were then supplied to the processing chamber. A titanium nitride thin film was formed on the substrate by thermal CVD at a temperature of 650°C. Subsequently, a purging step was performed to remove unreacted gases.

[0063] Next, hydrogen (H2) gas was supplied onto the titanium nitride thin film. Then, a 450 kHz low-frequency power supply with 450 W of power was applied to form a first plasma. Using the hydrogen plasma containing hydrogen ions activated by the first plasma, the titanium nitride thin film was surface-treated over a period of 10 seconds.

[0064] Next, ammonia (NH3) gas and hydrogen (H2) gas were supplied onto the first surface-treated titanium nitride thin film, respectively. A 450 kHz low-frequency power supply with 450 W of power was also applied to form a second plasma. Using the nitrogen plasma containing nitrogen ions activated by the second plasma, the titanium nitride thin film was subjected to nitriding for 30 seconds. This formed a titanium nitride thin film with a thickness of 802 Å on the substrate. The hydrogen plasma treatment and the second plasma treatment were each performed once.

[0065] <Example 2> A first plasma was formed by applying a 13.56 MHz high-frequency power supply at 450 W, and the titanium nitride thin film was surface-treated. Next, a second plasma was formed by applying a 13.56 MHz high-frequency power supply at 450 W, and the surface-treated titanium nitride thin film was subjected to nitriding using hydrogen plasma. Otherwise, the titanium nitride thin film was formed in the same manner as in Example 1. As a result, it was confirmed that the formed titanium nitride thin film had a thickness of 788 Å.

[0066] <Example 3> A titanium nitride thin film was formed in the same manner as in Example 1, except that a 450 kHz low-frequency power supply and a 13.56 MHz high-frequency power supply were applied at a power of 450 W each to form a first plasma and a second plasma, respectively, and then the surface was treated. This confirmed that the formed titanium nitride thin film had a thickness of 793 Å.

[0067] <Comparative Example> Except for not using the first and second plasmas for surface treatment, a titanium nitride thin film was formed on the substrate by a thermal CVD process using titanium tetrachloride gas and ammonia gas, respectively, in the same manner as in Example 1. The thickness of the formed titanium nitride thin film was confirmed to be 796 Å.

[0068] <Example of experiment> (1) Evaluation of the effects of hydrogen plasma treatment To evaluate the effects of hydrogen plasma treatment, the chloride ion concentration of thin films formed by the methods described in Examples 1 to 3 was evaluated by secondary ion mass spectrometry (SIMS), and the results are shown in Figure 7. At this time, thin films that were not treated with hydrogen plasma were also evaluated together as an untreated control group.

[0069] As shown in Figure 7, it was confirmed that the concentration of chloride ions decreased due to hydrogen plasma treatment, and in particular, it was confirmed that using dual plasma was the most effective in removing residual chloride ions.

[0070] (2) Evaluation of the effects of surface nitriding treatment 1 To evaluate the effect of surface nitriding on resistance, the thickness (in Å), stress (in MPa), average sheet resistance (Rs avg., in Ω / □), and sheet resistance uniformity (Rs Unif., in %) of the thin films formed by the methods described in the Examples and Comparative Examples were evaluated, and the results are shown in Table 1.

[0071] [Table 1]

[0072] As shown in Table 1, when using the methods described in the examples and comparative examples in the process of forming a titanium nitride thin film with a target thickness of 800 Å, it was confirmed that thin films without large deviations were formed in each case.

[0073] Furthermore, it was confirmed that surface nitriding treatment reduced film quality stress by more than 32% compared to the untreated control group, and in particular, when processing using dual plasma, it was confirmed that the stress was reduced by more than 48%.

[0074] Furthermore, by examining 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 that the physical properties were also improved when an HF power supply was applied.

[0075] (3) Evaluation of the effects of surface nitriding treatment 2 To evaluate the effect of plasma nitriding on the ability of thin films to form cracks, the film quality of thin films formed by the methods described in the examples and comparative examples was evaluated using an electron microscope, and the results are shown in Figure 8.

[0076] As shown in Figures 8(b), 8(c), and 8(d), no cracks occurred in any of the samples treated with plasma. However, as shown in Figure 8(a), cracks occurred only in the comparative example where plasma treatment was not used. These results confirm that plasma nitriding can prevent crack formation in thin films.

[0077] Based on the results described above, it was confirmed that when using the metal nitride thin film formation method according to the examples, even when forming thick metal nitride thin films, cracks are less likely to occur, and the resulting metal nitride thin films have low resistance and low residue concentration, thus possessing excellent electrical properties. [Explanation of Symbols]

[0078] 100 Substrate Processing Equipment 110 Process Chamber 120 Gas injection unit 130 Substrate mounting section 140 Plasma Power Supply Unit S substrate

Claims

1. A substrate preparation step involves preparing the substrate in a process chamber where a processing space has been formed, A thin film formation step involves supplying a metal precursor gas and a nitrogen-containing gas, respectively, to form a metal nitride thin film on the substrate. A first surface treatment step involves supplying a hydrogen-containing gas to the process chamber, forming a first plasma, and surface-treating the metal nitride thin film multiple times. 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 to form a second plasma and surface treating the first surface-treated substrate multiple times.

2. The method for forming a metal nitride thin film according to claim 1, characterized in that the thin film formation step involves reacting the metal precursor gas and the nitrogen-containing gas by a thermochemical vapor deposition method carried out at a temperature of 300 to 800°C to form the metal nitride thin film.

3. The aforementioned metal nitride thin film is titanium nitride (TiN), tungsten nitride (WN), molybdenum nitride (Mo ２ A method for forming a metal nitride thin film according to claim 1, characterized by comprising one of N), tantalum nitride (TaN), aluminum nitride (AlN), and titanium aluminum nitride (TiAlN).

4. The aforementioned metal precursor gas is titanium tetrachloride (TiCl ４ ), tetrakis(dimethylamino)titanium (TDMAT, Ti(N(Me ２ ) ４ )), Tetrakis(diethylamino)titanium (TDEAT, Ti(N(Et ２ ) ４ )), and tetrakis(ethylmethylamino)titanium (TEMAT, Ti(N(EtMe) ４ A method for forming a metal nitride thin film according to claim 1, characterized by comprising any one of the following metal precursors.

5. The nitrogen-containing gas is ammonia (NH ３ ) gas and nitrogen (N ２ ) gas, characterized in that it comprises at least one of the above, the method for forming a metal nitride thin film according to claim 1.

6. The method for forming a metal nitride thin film according to claim 1, characterized in that the first surface treatment step involves applying a dual-frequency power supply to form the first plasma.

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

8. The method for forming a metal nitride thin film according to claim 1, characterized in that the second surface treatment step involves applying a dual-frequency power supply to form the second plasma.

9. The method for forming a metal nitride thin film according to claim 8, 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. The method for forming a metal nitride thin film according to claim 1, characterized in that the second surface treatment step further involves supplying a hydrogen-containing gas.

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