Method for nitriding metal oxide films and method for manufacturing semiconductor device using the same

Abstract

A method for nitriding a metal oxide film according to an embodiment is a method for nitriding a metal oxide film using a substrate processing apparatus comprising: a process chamber having a processing space formed therein for processing a substrate; a gas injection unit for supplying gas to the processing space; a substrate mounting unit installed opposite to the gas injection unit and having a substrate mounted thereon; and a plasma power supply unit for supplying RF power to form a plasma in the processing space, comprising the steps of: preparing a substrate having a metal oxide film formed thereon; and applying RF power to form a plasma in the processing space and supplying a nitrogen-containing gas to diffuse nitrogen radicals into the metal oxide film; wherein the step of diffusing nitrogen radicals into the metal oxide film comprises the step of maintaining the processing space at a first pressure to diffuse the nitrogen radicals into the metal oxide film and the step of maintaining the processing space at a second pressure different from the first pressure to diffuse the nitrogen radicals into the metal oxide film.

Description

Technology Field

[0001] The present invention relates to a method for nitriding a metal oxide film and a method for manufacturing a semiconductor device using the same. Background Technology

[0002] Semiconductor transistors are structurally evolving from planar type to gate-all-around (GAA).

[0003] In order to manufacture a semiconductor device having the above-mentioned GAA structure, a method is utilized in which the metal oxide film formed in the stack of the GAA structure is nitrified to form a metal oxide nitride layer with the goal of controlling the thickness of the metal oxide film formed in the stack, and the formed metal oxide nitride layer is etched using an etching component.

[0004] However, since the aforementioned metal oxide film has a slow nitriding rate, there is a problem in that the process time required to increase the nitrogen content on the metal oxide film to a target amount is long. In addition, if the degree of nitriding on the surface of the metal oxide film—that is, if the thickness of the nitrided metal oxide film—is too thick, there is a risk of causing damage to the underlying film; therefore, it is necessary to secure technology capable of precisely controlling the degree of nitriding of the metal oxide film.

[0005] In addition, for metal oxide films formed on GAAs having a three-dimensional structure, uniform etching selectivity can be secured only if nitridation is induced uniformly from the top to the bottom of the metal oxide film. However, there is a problem in that it is difficult to induce uniform nitridation in the top and bottom regions of the three-dimensional metal oxide film, so research is needed on a method to compensate for this. The problem to be solved

[0006] According to one embodiment, the invention aims to provide technical details regarding a method for nitriding a metal oxide film and a method for manufacturing a semiconductor device utilizing the same, which allows the metal oxide film to be nitrided in a short time to minimize damage to the metal oxide film and precisely control the degree of nitridation of the metal oxide film.

[0007] In addition, the invention aims to provide technical details regarding a method for nitriding a metal oxide film that enables uniform nitriding induction even for a metal oxide film with a three-dimensional structure, thereby enabling the formation of a metal oxide film with excellent etching selectivity, and a method for manufacturing a semiconductor device using the same. means of solving the problem

[0008] A method for nitriding a metal oxide film according to an embodiment is a method for nitriding a metal oxide film using a substrate processing apparatus comprising: a process chamber having a processing space formed therein for processing a substrate; a gas injection unit for supplying gas to the processing space; a substrate mounting unit installed opposite to the gas injection unit and having a substrate mounted thereon; and a plasma power supply unit for supplying RF power to form a plasma in the processing space, comprising the steps of: preparing a substrate having a metal oxide film formed thereon; and applying RF power to form a plasma in the processing space and supplying a nitrogen-containing gas to diffuse nitrogen radicals into the metal oxide film; wherein the step of diffusing nitrogen radicals into the metal oxide film may include the step of maintaining the processing space at a first pressure to diffuse the nitrogen radicals into the metal oxide film and the step of maintaining the processing space at a second pressure different from the first pressure to diffuse the nitrogen radicals into the metal oxide film.

[0009] According to one embodiment, the metal oxide film may comprise at least one metal among aluminum (Al), tungsten (W), titanium (Ti), hafnium (Hf), tantalum (Ta), and zirconium (Zr).

[0010] According to one embodiment, the nitrogen-containing gas is nitrogen (N2) gas, nitrous oxide (N2O) gas, nitrogen dioxide (NO2) gas, nitric oxide (NO) gas, ammonia (NH3) gas, amine (N X H Y It may include at least one of the gases.

[0011] According to one embodiment, the step of diffusing nitrogen radicals into the metal oxide film can be performed by supplying the nitrogen-containing gas at a flow rate of 500 to 20,000 sccm.

[0012] According to one embodiment, the first pressure is higher than the second pressure, and the first pressure and the second pressure may have a deviation in the range of 3 to 7 Torr.

[0013] According to one embodiment, the step of diffusing nitrogen radicals into the metal oxide film may have a first execution time for maintaining the first pressure and a second execution time for maintaining the second pressure that are different from each other.

[0014] Meanwhile, a method for manufacturing a semiconductor device according to an embodiment may include the steps of: preparing a substrate comprising a plurality of channel layers formed on the upper surface, a gate electrode layer having a gate-all-around (GAA) structure formed to surround the channel layers, and a metal oxide capping layer formed to surround the gate electrode layer; nitriding the metal oxide capping layer by the method described above; and etching the nitrided metal oxide capping layer.

[0015] According to one embodiment, the substrate comprises a device insulating layer formed on the upper surface of the substrate;

[0016] The device may have a structure comprising: a first dielectric layer formed on the upper surface of the above-mentioned device insulating film; a first gate electrode layer formed on the upper surface of the above-mentioned device insulating film; a plurality of channel layers formed on the upper surface of the above-mentioned substrate; a second dielectric layer formed to surround each of the plurality of GAA channels; a second gate electrode layer formed to surround the second dielectric film; a metal oxide film capping layer formed on the upper surface of the first gate electrode layer to surround the second gate electrode layer; and a photoresist pattern layer formed on the surface of the metal oxide film capping layer. Effects of the invention

[0017] The nitriding method of a metal oxide film according to the embodiment allows for precise control of the degree of nitriding and the thickness of the nitriding of the metal oxide film by diffusing nitrogen radicals under different pressure conditions through pressure ramping down during the process of diffusing nitrogen radicals into the metal oxide film.

[0018] In addition, the nitrification method of a metal oxide film according to the embodiment can nitrify the metal oxide film in a short time by utilizing a method of supplying nitrogen radicals formed using a high-frequency RF power source to the metal oxide film, minimize surface damage to the metal oxide film, and improve the etching selectivity of the metal oxide film. Brief explanation of the drawing

[0019] FIG. 1 is a schematic diagram showing a substrate processing apparatus according to one embodiment. Figure 2 is a process diagram showing a method for nitriding a metal oxide film according to an example. Figure 3 is a schematic diagram showing a method for nitriding a metal oxide film according to an embodiment. Figure 4 is a graph showing pressure control in the nitriding method of a metal oxide film according to an example. FIG. 5 is a schematic diagram showing a method for manufacturing a semiconductor device according to an embodiment. Figure 6 is the result of analyzing the nitridation thickness trend of aluminum oxide films treated with nitridation according to the method of Example and Comparative Example 2. Specific details for implementing the invention

[0020] The nitriding method of a metal oxide film according to the embodiment can be performed using a substrate processing apparatus of various conventional structures used to process a substrate. For example, FIG. 1 is a configuration diagram showing a substrate processing apparatus according to one embodiment.

[0021] Referring to FIG. 1, a substrate processing device (100) according to an embodiment has a structure including a process chamber (110), a gas injection unit (120), a substrate mounting unit (130), and a plasma power supply unit (140).

[0022] The process chamber (110) may have a structure in which a hermetic processing space (111) for substrate processing is formed. The process chamber (110) may have a structure including a chamber body (113) that defines the processing space (111) and an upper lid (115) located at the top of the chamber body (113).

[0023] The gas injection unit (120) may be installed in the process chamber (110) to supply gas supplied from outside the process chamber (110) to the processing space (111). The gas injection unit (120) may be installed above the process chamber (110) opposite the substrate mounting unit (130) to inject gas into the processing space (111). The gas injection unit (120) may be connected to a gas supply unit (not shown) to receive a process gas, such as nitrogen-containing gas, and inject it into the processing space (111).

[0024] For example, the gas injection unit (120) may have various shapes, such as a shower head shape or a nozzle shape. If the gas injection unit (120) is in the shape of a shower head, the gas injection unit (120) may be coupled to the process chamber (110) in a manner that covers the upper lid (115) of the process chamber (110).

[0025] The substrate mounting portion (130) is installed in the process chamber (110) opposite to the gas injection portion (120), and a substrate (S) can be mounted thereon. The substrate mounting portion (130) may have a structure including a mounting plate (131) and a support (133). The substrate mounting portion (130) may have a structure that moves up and down in the upper and lower directions, connected to a separate driving unit (not shown). The substrate mounting portion (130) may include a heater (135) installed inside the mounting plate (131) and can heat a substrate for performing a thin film formation process.

[0026] The plasma power supply unit (140) may include at least one RF (radio frequency) power source to apply at least one RF power source to the process chamber (110) in order to form a plasma atmosphere inside the process chamber (110). In particular, the plasma power supply unit (140) may be connected to apply high frequency (HF) RF power to the gas injection unit (120). In this case, the gas injection unit (120) may be referred to as a power supply electrode or an upper electrode. The plasma power supply unit (140) may include an impedance matching means (not shown) disposed between the plasma power supply unit (140) and the gas injection unit (120) for impedance matching between the RF power source and the process chamber (110).

[0027] In addition, the plasma power supply unit (140) can supply high-frequency RF power having a frequency range of 13.56 to 70 MHz. Furthermore, the plasma power supply unit (140) can supply high-frequency RF power with a preset duty cycle to form a pulsed wave plasma in the processing space.

[0028] Meanwhile, FIG. 2 is a process diagram showing a method for nitriding a metal oxide film according to an embodiment. FIG. 3 is a schematic diagram showing a method for nitriding a metal oxide film according to an embodiment.

[0029] Referring to FIGS. 2 and FIGS. 3, a method for nitriding a metal oxide film according to an embodiment includes the step of preparing a substrate on which a metal oxide film is formed (S100) and the step of forming a metal nitride layer on the metal oxide film (S200).

[0030] The step of preparing the substrate (S100) involves preparing a substrate (10) having a metal oxide film (20) formed on its upper surface, and placing the substrate (10) having the metal oxide film (20) formed thereon inside the processing space of a process chamber (110).

[0031] The metal oxide film (20) may include at least one metal among aluminum (Al), tungsten (W), titanium (Ti), hafnium (Hf), tantalum (Ta), and zirconium (Zr). The metal oxide film (20) may include a single metal but is not limited thereto, and may be a mixed metal oxide film including one or more metals.

[0032] Additionally, the metal oxide film (20) may be a single layer, but is not limited thereto, and may be a multiple layer, or a composite metal oxide film in which a metal oxide film containing a heterogeneous metal is stacked in multiple layers.

[0033] In the step (S200) of diffusing nitrogen radicals into the metal oxide film (20), an RF power source is applied to form a plasma in the processing space (111) and a nitrogen-containing gas is supplied to diffuse nitrogen radicals into the metal oxide film (20).

[0034] In this step, the process can be configured to form a metal oxide nitride film in which nitrogen is diffused at an atomic ratio of 25 to 35% relative to the metal atoms contained in the metal oxide film. At this time, nitrogen radicals can diffuse from the surface of the metal oxide film (20) to a certain depth to form a metal oxide nitride layer to a certain depth on the metal oxide film.

[0035] Specifically, in this step, an RF power source is applied to either the gas injection unit (120) or the substrate mounting unit (130) to form a plasma in the processing space (111). Then, a nitrogen-containing gas is injected into the processing space (111) where the plasma is formed. Accordingly, nitrogen radicals are generated in the nitrogen-containing gas by the plasma, and the metal oxide film is exposed to the generated nitrogen radicals. Subsequently, nitrogen radicals diffuse into the metal oxide film, allowing a part or the whole of the metal oxide film to form a metal oxide nitride layer.

[0036] In this step, the process can be performed by applying a high-frequency RF power source having a frequency range of 13.56 to 70 MHz. Accordingly, the charge density can be increased and the mean free path can be increased to promote the diffusion of nitrogen radicals within the metal oxide film.

[0037] In this step, when a high-frequency RF power source with a frequency range of less than 13.56 MHz is applied, the nitriding rate is slow and it is difficult to control the nitrogen diffusion thickness within the metal oxide film (20), so the thickness of the metal oxide layer of the nitrided nitride tends to increase excessively until the target dispersion is formed, and as a result, there is a problem of the etching thickness increasing.

[0038] In particular, when a low-frequency RF power source with a frequency range of less than 3000 KHz is applied, there is a risk that surface damage to the metal oxide film may increase.

[0039] In addition, in this step, the metal oxide film (20) may be nitrided by supplying the high-frequency RF power at a preset duty cycle to form a pulsed wave plasma. When the pulsed wave plasma is generated, the diffusion concentration of nitrogen within the metal oxide film (20) and the thickness of the nitrided metal oxide layer can be precisely controlled.

[0040] To this end, in this step, a pulsed plasma having a duty ratio of 10 to 90% may be formed to form a metal oxide nitride layer on the metal oxide film (20).

[0041] In addition, in this step, a high-frequency RF power source of 100 to 2,000 W can be applied to form a metal oxide nitride layer on the metal oxide film (20).

[0042] The above nitrogen-containing gas is nitrogen (N2) gas, nitrous oxide (N2O) gas, nitrogen dioxide (NO2) gas, nitric oxide (NO) gas, ammonia (NH3) gas, amine (N X H Y It may include at least one of the gases.

[0043] As the above nitrogen-containing gas increases, it is difficult to control the thickness of the metal nitride oxide layer and the thickness of the metal nitride oxide layer tends to increase, so any one of nitrogen (N2) gas, nitrous oxide (N2O) gas, nitrogen dioxide (NO2) gas, or nitric oxide (NO) gas may be used. In particular, nitrogen (N2) gas may be used as the above nitrogen-containing gas.

[0044] In this step, a nitrogen-containing gas can be supplied to the processing space at a flow rate of 500 to 20,000 sccm to form a metal oxide nitride layer on the metal oxide film (20).

[0045] When the flow rate of the above nitrogen-containing gas is less than 500 sccm, the amount of nitrogen diffused into the metal oxide film (20) is low, and when it exceeds 20,000 sccm, it is difficult to expect additional improvement effects.

[0046] In this step, a metal oxide nitride layer can be formed on the metal oxide film under pressure conditions of greater than 0 Torr and less than or equal to 15 Torr.

[0047] Specifically, the present step may include the step of maintaining the processing space at a first pressure to diffuse the nitrogen radical into the metal oxide film (20) and the step of maintaining the processing space at a second pressure different from the first pressure to diffuse the nitrogen radical into the metal oxide film (20).

[0048] Figure 4 is a graph showing pressure control in the nitriding method of a metal oxide film according to an example.

[0049] Referring to FIG. 4, in this step, nitrogen radicals are diffused into the metal oxide film (20) by maintaining the pressure of the processing space at a first pressure, and nitrogen radicals are diffused into the metal oxide film (20) while maintaining the pressure at a second pressure by ramping down. If nitrogen radicals are diffused for a certain period of time under high pressure conditions as described above, and then nitrogen radicals are diffused for a certain period of time under low pressure conditions, a metal oxide nitride layer in which nitrogen radicals are uniformly diffused can be formed on the metal oxide film (20).

[0050] More specifically, when nitrogen radicals are diffused into a metal oxide film (20) under a single pressure condition, nitrogen radicals are concentrated at a certain depth within the metal oxide film (20) depending on the pressure, making it difficult to achieve uniform diffusion of nitrogen radicals (20). To compensate for this, if nitrogen radicals are diffused for a certain period of time under a first pressure condition and then diffused for a certain period of time under a second pressure condition which is relatively low pressure, the linearity of the nitrogen radicals within the film material of the metal oxide film (20) increases under the low pressure condition, thereby providing the effect of uniformly diffusing nitrogen radicals within the film material of the metal oxide film (20). In particular, when nitrogen radicals are diffused under a high pressure condition, nitrogen radicals diffuse into an area relatively close to the surface of the metal oxide film (20), and when nitrogen radicals are diffused under a low pressure condition, the diffusion depth increases relatively due to the increased linearity of the nitrogen radicals, thereby providing the effect of uniformly diffusing nitrogen radicals to the lower region of the metal oxide film (20).

[0051] At this time, the first pressure may have a range of 5 Torr or more and 15 Torr or less, and the second pressure may have a range of 0 Torr or more and less than 5 Torr. The first pressure and the second pressure may be selectively adjusted as needed within the above ranges.

[0052] In addition, the first pressure and the second pressure may have a deviation in the range of 3 to 7 Torr. If the deviation is less than 3 Torr or exceeds 7 Torr, there is a problem that it is difficult to control the diffusion of nitrogen radicals within the metal oxide film (20). In particular, when a dielectric film, etc. is formed on the lower part of the metal oxide film, the above conditions can be maintained to control the diffusion of nitrogen radicals into the thin film located on the lower part of the metal oxide film.

[0053] And, the step of nitriding the metal oxide (20) can be performed for 50 to 600 seconds, and the thickness of the nitrided metal oxide layer formed in the metal oxide film can be controlled by adjusting the processing time.

[0054] In addition, in this step, nitrogen radicals can be diffused into the metal oxide film by making the first execution time (t1) for maintaining the first pressure and the second execution time (t2) for maintaining the second pressure equal to each other or different from each other. That is, when performing the step of nitrating the metal oxide (20) for a total of 500 seconds, the first execution time (t1) can be set to 200 seconds and the second execution time (t2) to 300 seconds. The execution times can be selectively adjusted as needed.

[0055] In addition, after performing the above step, the process can be configured to perform a purging step in which a purge gas is supplied to the processing space and the processing space is exhausted to remove residue.

[0056] The nitriding method of a metal oxide film according to the above-described embodiment allows for the diffusion of nitrogen radicals under different pressure conditions through pressure ramping down during the process of diffusing nitrogen radicals into the metal oxide film (20), thereby enabling precise control of the degree of nitriding and the thickness of the nitriding of the metal oxide film (20).

[0057] In addition, the nitrification method of a metal oxide film according to the embodiment can nitrify the metal oxide film (20) in a short time by utilizing a method of supplying nitrogen radicals formed by utilizing a high-frequency RF power source to the metal oxide film (20), minimize surface damage to the metal oxide film (20), and improve the etching selectivity of the metal oxide film (20).

[0058] Meanwhile, this is a schematic diagram showing a method for manufacturing a semiconductor device according to an embodiment.

[0059] Referring to FIG. 5, a method for manufacturing a semiconductor device according to an embodiment may include the steps of: preparing a substrate; nitriding a metal oxide capping layer formed on the substrate; and etching the nitrided metal oxide capping layer.

[0060] First, in the step of preparing the substrate (10), a substrate including a plurality of channel layers (14) and a metal oxide capping layer (20a) is prepared.

[0061] The above substrate (10) may have a structure in which a thin film, such as an insulating layer, a dielectric layer, or a sacrificial layer, is formed on the upper surface.

[0062] Additionally, the substrate (10) may have a structure comprising: a plurality of channel layers (14) formed on the upper surface of the substrate (10); an insulating layer (15) formed to surround each of the plurality of channel layers (14); a dielectric layer (16) formed to surround the insulating layer (15); a metal oxide film capping layer (20a) formed to surround the dielectric layer (16); and a photoresist layer (30) formed on the surface of the metal oxide film capping layer (20a). The photoresist layer (30) may be patterned through a patterning process to form a photoresist pattern layer (30a).

[0063] A step of nitriding the metal oxide capping layer (20a) can be performed by placing the substrate (10) as described above onto a substrate mounting portion (130) installed inside a process chamber. The nitriding of the metal oxide capping layer (20a) can be achieved by performing the same method as the nitriding of the metal oxide film described above. In this step, the metal oxide capping layer (20a), whose surface is exposed by the photoresist pattern layer (30), can be nitrided to form a metal oxynitride on the metal oxide capping layer (20a), thereby forming a nitrided metal oxide capping layer (20b). In particular, by utilizing the nitriding method of the metal oxide film described above, nitrogen radicals can be controlled so as not to diffuse on the first dielectric layer (12) and the second dielectric layer (16) formed on the lower part of the metal oxide capping layer (20a).

[0064] The metal oxide capping layer (20a) having the above-described three-dimensional structure can be nitrided through the nitriding method of the metal oxide film according to the embodiment, so that the nitriding process can be uniformly performed to a target thickness from the lower region of the metal oxide capping layer (20a) adjacent to the substrate to the upper region of the metal oxide capping layer (20a) located at a relatively far distance from the substrate.

[0065] Next, in the step of etching the nitrided metal oxide capping layer (20b), the nitrided metal oxide capping layer (20b) can be etched using various conventional methods used to etch metal oxynitrides, thereby exposing the surface of the substrate (10) and the second dielectric layer (16). After exposing the surface of the substrate (10) and the second dielectric layer (16) by etching the nitrided metal oxide capping layer (20b) as described above, a gate (not shown) in contact with the substrate (10) and the second dielectric layer (16) is formed, and a semiconductor device can be manufactured through this method.

[0066] In the method for manufacturing a semiconductor device according to the above embodiment, the method may be configured to completely remove a metal oxide film formed in a specific region of the substrate by performing a unit cycle including the step of nitriding the metal oxide film capping layer (20a) and the step of etching the nitrided metal oxide film capping layer (20b) at least once as needed.

[0067] The present invention will be explained in more detail below with reference to examples.

[0068] The presented embodiments are merely specific examples of the invention and are not intended to limit the technical scope of the invention.

[0069] < Examples >

[0070] A substrate with an aluminum oxide film deposited on its upper surface was prepared. The prepared substrate was placed on the substrate mounting area inside the process chamber.

[0071] Nitrogen (N2) gas was supplied into the processing space at a flow rate of 8,000 to 12,000 sccm, and a high-frequency RF power source of 27.12 MHz was applied at a power of 300 to 800 W to form nitrogen radicals, and the aluminum oxide film was subjected to a first nitriding treatment for a first time under first pressure conditions. Afterward, the pressure in the processing space was ramped down to a second pressure, and the aluminum oxide film was subjected to a second nitriding treatment for a second time. At this time, the first pressure and the second pressure had a deviation of 4 Torr, and the first pressure was controlled to have a higher pressure value than the second pressure.

[0072] < Comparative example 1>

[0073] The aluminum oxide film was nitrided in the same manner as in the example, except that the aluminum oxide film was nitrided under conditions where the processing space maintained a first pressure.

[0074] < Comparative example 2>

[0075] The aluminum oxide film was nitrided in the same manner as in the example, except that the aluminum oxide film was nitrided under conditions where the processing space maintained a second pressure.

[0076] < Experimental Example >

[0077] (1) Pressure of the metal oxide film Nitriding Assessment of impact

[0078] In order to evaluate the effect of pressure on the nitridation of a metal oxide film during the nitridation process of a metal oxide film using nitrogen radicals, the pressure in the treatment space was controlled to a second pressure, an intermediate pressure, and a first pressure, respectively, and the nitridation treatment was performed while maintaining the corresponding pressure continuously. The thickness of the nitrided metal oxide film was measured, and the results are shown in Table 1 below. At this time, the first pressure was the highest pressure state, the second pressure was the lowest pressure state, and the nitridation treatment was performed by controlling the intermediate pressure value between the first pressure and the second pressure as the intermediate pressure.

[0079] Process variables nitrification Thickness (Å) Second pressure Same as above 29 Medium pressure 24 First pressure 17

[0080] As shown in Table 1, when the first pressure was maintained constant, the nitridation thickness of the metal oxide film in which nitrogen radicals penetrated was found to be 17 Å, 24 Å for the intermediate pressure, and 29 Å for the second pressure, which is the lowest pressure.

[0081] Through the above results, it was confirmed that pressure affects the nitridation depth of the metal oxide film during the nitridation process.

[0082] (2) Evaluation of the effect of pressure control performed during the nitriding process on nitriding

[0083] In order to evaluate the effect of pressure ramping down performed during the nitriding process on nitriding, the nitriding thickness trends of an aluminum oxide film nitrided by the method according to the example and an aluminum oxide film nitrided by the method according to Comparative Example 2 were analyzed, and the results are shown in Fig. 6.

[0084] As shown in Fig. 6, in Comparative Example 2, in which nitriding treatment was performed while maintaining the second pressure continuously, it was confirmed that nitrogen radicals diffused intensively into the aluminum oxide film at a depth of around 29 Å, and that nitrogen radicals did not diffuse uniformly throughout the aluminum oxide film. On the other hand, in the case where the first pressure was maintained for a certain period of time as in the example and then the pressure was ramped down to the second pressure, it was confirmed that as time passed during the process of performing nitriding treatment at the relatively low second pressure, the diffusion depth of nitrogen radicals gradually increased, showing a tendency for nitrogen radicals to diffuse throughout the aluminum oxide film, and that the thickness at which nitrogen diffusion becomes saturated increased.

[0085] Through the results described above, it was confirmed that pressure ramping down from high pressure to low pressure during the nitriding process can induce uniform nitriding across the entire aluminum oxide film. In particular, it was confirmed that at high pressure, nitriding is induced relatively on the surface of the aluminum oxide film, while ramping down to low pressure increases the penetration depth of nitrogen radicals into the interior of the aluminum oxide film. Furthermore, as time progresses, the linearity of nitrogen radicals increases, causing the penetration depth to gradually increase, making nitriding possible even in the lower depth region of the aluminum oxide film.

[0086] In addition, it was determined that the nitridation depth of the aluminum oxide film could be selectively controlled by adjusting the first processing time (t1) under high pressure conditions and the second processing time (t2) under low pressure conditions differently. Explanation of the symbols

[0087] 10: Substrate 11: First insulating layer 12: First dielectric layer 13: First Sacrifice Layer 14: Channel layer 15: Second insulating layer 16: Second dielectric layer 20: Metal oxide film 20a: Metal oxide capping layer 20b: Nitrided metal oxide capping layer 30: Photoresist layer 30a: Photoresist pattern layer 110: Process Chamber 111: Processing space 113: Chamber body 115: Chamber Lead 120: Gas injection unit 130: Substrate mounting area 131: Seating plate 133: Support 135: Heater 140: Plasma power supply

Claims

Claim 1 A method for nitriding a metal oxide film using a substrate processing apparatus comprising: a process chamber having a processing space formed therein for processing a substrate; a gas injection unit for supplying gas to the processing space; a substrate mounting unit installed opposite to the gas injection unit and having a substrate mounted thereon; and a plasma power supply unit for supplying RF power to form a plasma in the processing space, the method comprising: a step of preparing a substrate having a metal oxide film formed thereon; and a step of applying RF power to form a plasma in the processing space and supplying a nitrogen-containing gas to diffuse nitrogen radicals into the metal oxide film; wherein the step of diffusing nitrogen radicals into the metal oxide film comprises a step of maintaining the processing space at a first pressure to diffuse the nitrogen radicals into the metal oxide film and a step of maintaining the processing space at a second pressure different from the first pressure to diffuse the nitrogen radicals into the metal oxide film. Claim 2 A method for nitriding a metal oxide film according to claim 1, wherein the metal oxide film comprises at least one metal selected from aluminum (Al), tungsten (W), titanium (Ti), hafnium (Hf), tantalum (Ta), and zirconium (Zr). Claim 3 In claim 1, the RF power source is a method for nitriding a metal oxide film having a frequency range of 13.56 to 70 MHz. Claim 4 In claim 1, the nitrogen-containing gas is nitrogen (N2) gas, nitrous oxide (N2O) gas, nitrogen dioxide (NO2) gas, nitric oxide (NO) gas, ammonia (NH3) gas, amine (N X H Y A method for nitriding a metal oxide film comprising at least one of the following gases. Claim 5 A method for nitriding a metal oxide film according to claim 1, wherein the step of diffusing nitrogen radicals into the metal oxide film is performed by supplying the nitrogen-containing gas at a flow rate of 500 to 20,000 sccm. Claim 6 A method for nitriding a metal oxide film according to claim 1, wherein the first pressure is higher than the second pressure. Claim 7 A method for nitriding a metal oxide film according to claim 1, characterized in that the first pressure and the second pressure have a deviation in the range of 3 to 7 Torr. Claim 8 A method for nitriding a metal oxide film according to claim 1, wherein the step of diffusing nitrogen radicals into the metal oxide film is characterized in that the first execution time for maintaining the first pressure and the second execution time for maintaining the second pressure are different from each other. Claim 9 A method for manufacturing a semiconductor device comprising: a step of preparing a substrate including a plurality of channel layers formed on the upper surface, a gate electrode layer having a gate-all-around (GAA) structure formed to surround the channel layers, and a metal oxide capping layer formed to surround the gate electrode layer; a step of nitriding the metal oxide capping layer by a method described in any one of claims 1 to 8; and a step of etching the nitrided metal oxide capping layer. Claim 10 A method for manufacturing a semiconductor device according to claim 9, wherein the substrate comprises: a device insulating layer formed on the upper surface of the substrate; a first dielectric layer formed on the upper surface of the device insulating film; a first gate electrode layer formed on the upper surface of the first dielectric film; a plurality of channel layers formed on the upper surface of the substrate; a second dielectric layer formed to surround each of the plurality of GAA channels; a second gate electrode layer formed to surround the second dielectric film; a metal oxide film capping layer formed on the upper surface of the first gate electrode layer to surround the second gate electrode layer; and a photoresist pattern layer formed on the surface of the metal oxide film capping layer.

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