Substrate processing method and substrate processing apparatus

Abstract

The present invention relates to a substrate processing method and a substrate processing apparatus for etching, in atomic layer units, a thin film formed on a substrate according to one embodiment of the present invention, the substrate processing method comprising: a surface modification step for modifying a thin film formed on the substrate according to an atomic layer unit; modifying the surface of the thin film by supplying a first gas containing chlorine oxygen (O) to a processing space of a chamber in which the substrate is disposed; a first purge step of supplying a purge gas to the processing space to remove the first gas remaining in the processing space; an etching step of supplying CHF3 gas to the processing space to etch the modified thin film; and a second purge step of supplying a purge gas to the processing space to remove the CHF3 gas remaining in the processing space.

Description

Technical Field

[0001] The present invention relates to a substrate processing method and a substrate processing device, and more particularly to a substrate processing method and a substrate processing device for etching a tantalum nitride film in atomic layer units. Background Art

[0002] Recently, the demand for memory devices has been increasing rapidly due to smartphones, tablet PCs, and SSDs (Solid State Drives), etc. In particular, the demand for low-power and highly integrated large-capacity flash memories is increasing.

[0003] In the case of conventional 2D structured flash memory, as the line width of the cell decreases, the interference between cells increases, resulting in leakage current. To solve this problem, the three-dimensional stacked 3D NAND flash memory structure has attracted much attention. If vertical stacking is used, more cells can be implemented in the same silicon area, which has the advantages of reducing manufacturing costs and increasing capacity.

[0004] Generally, a 3D NAND flash memory alternately stacks silicon oxide films and silicon nitride films, and etches the stacked layers to form source lines and word lines. Figure 1 is a diagram showing a portion of a process for manufacturing a 3D NAND flash memory. Figure 1 , various materials such as tunnel oxide, nitride film well, gate insulation layer, barrier layer and gate can be deposited on the word line, and etched to form the nitride film well to manufacture 3D NAND flash memory. Such 3D NAND flash memory has recently increased the number of stacking levels and fine patterns in order to increase capacity, so the importance of etching process in the manufacturing process of 3D NAND flash memory has gradually increased.

[0005] In the case where the gate material, that is, metal, flows into the silicon oxide film or the silicon nitride film, it may cause a defect in the device, so a barrier layer is provided to prevent the gate material from flowing into the silicon oxide film or the silicon nitride film. A tantalum nitride film can be used as the material constituting the barrier layer. Usually, after the tantalum nitride film is evaporated, the tantalum nitride film is etched by an etching process to make the evaporated film uniform.

[0006] Tantalum nitride films are mainly etched by reactive ion etching (RIE), but due to the disadvantage that it is difficult to control the etching amount, they are recently being etched by atomic layer etching (ALE).

[0007] A method for etching a tantalum nitride film using an atomic layer etching process is proposed in Non-Patent Document 1. The etching process of Non-Patent Document 1 is to oxidize a tantalum nitride film, which is a substance containing oxygen, to form a tantalum oxide film. It is proposed to supply BCl to the tantalum oxide film. 3 After the tantalum oxide film is modified by supplying a gas, hydrogen fluoride (HF) gas is supplied to etch the modified tantalum oxide film. However, no proposal is made regarding the characteristics of the etched tantalum nitride film (eg, surface roughness, etching selectivity, etc.).

[0008] Non-patent literature 1: Nicholas Johnson, "ATOMIC LAYER ETCHING OF METAL FILMS, METAL NITRIDESM AND METAL OXIDES WITH BCL3AND HF / XEF2": 2019 Summary of the invention

[0009] In order to solve the problems of the prior art, the present invention provides a new tantalum nitride film etching method and a substrate processing device therefor, which have excellent etching selectivity for silicon oxide films and silicon nitride films and can ensure a small surface roughness even after etching.

[0010] The problems to be solved by the present invention are not limited to the problems mentioned above, and a person skilled in the art can clearly understand other problems not mentioned from the following description.

[0011] A method for etching a thin film formed on a substrate according to an embodiment of the present invention in atomic layer units, comprising: a surface modification step, supplying a first gas containing oxygen (O) to a processing space of a chamber in which the substrate is arranged to modify the surface of the thin film; a first purge step, supplying a purge gas to the processing space to remove the first gas remaining in the processing space; an etching step, supplying CHF to the processing space 3 Gas to etch the modified film; and a second purge step, supplying purge gas to the processing space to remove the CHF remaining in the processing space 3 gas.

[0012] In one embodiment, the cycle including the surface modification step to the second purge step may be repeated one or more times.

[0013] In one embodiment, the thin film may be a tantalum nitride film.

[0014] In one embodiment, the substrate may include at least one of a silicon oxide film and a silicon nitride film.

[0015] In one embodiment, the substrate may include a stacked film in which silicon oxide films and silicon nitride films are alternately stacked, and the tantalum nitride film is formed in an opening that penetrates the stacked film.

[0016] In one embodiment, the first gas may include O 2 , O 3 At least one of .

[0017] In one embodiment, the surface modification step and the etching step may be performed in a state where plasma is generated in the processing space.

[0018] In one embodiment, the surface modification step to the second purge step may be performed in a state where the substrate is heated to a predetermined temperature.

[0019] In one embodiment, the predetermined temperature may be 100°C to 150°C.

[0020] A substrate processing apparatus according to an embodiment of the present invention comprises: a chamber having a processing space therein; a substrate supporting unit disposed in the processing space and comprising a heating component for heating the substrate while supporting the substrate; and a gas supply unit for supplying a first gas containing oxygen (O) and CHF to the processing space. 3 a plasma generating unit for plasma-forming the gas supplied from the gas supply unit; and a control unit for controlling the gas supply unit and the plasma generating unit, wherein the control unit controls the gas supply unit and the plasma generating unit, thereby controlling the plasma of the first gas to be generated in the processing space to modify the thin film formed on the substrate and generate the CHF 3 The modified thin film formed on the substrate is etched by the gas plasma.

[0021] In one embodiment, the thin film may be a tantalum nitride film.

[0022] In one embodiment, the first gas may include O 2 , O 3 At least one of .

[0023] In one embodiment, the substrate may include a stacked film in which silicon oxide films and silicon nitride films are alternately stacked, and the tantalum nitride film is formed in an opening that penetrates the stacked film.

[0024] In one embodiment, the control unit may control the heating component to maintain the temperature of the substrate at 100° C. to 150° C.

[0025] A method for etching a thin film formed on a substrate for manufacturing a 3D NAND device according to an embodiment of the present invention in atomic layer units, comprising: a surface modification step of supplying a first gas containing oxygen (O) to a processing space of a chamber in which the substrate is arranged to modify the surface of the thin film; a first purge step of supplying a purge gas to the processing space to remove the first gas remaining in the processing space; an etching step of supplying CHF to the processing space 3 and etching the modified film; and a second purge step, supplying a purge gas to the processing space to remove the CHF remaining in the processing space. 3 gas, the first gas comprising O 2 , O 3 In at least any one of the above, the surface modification step to the second purge step constitute one cycle and are repeatedly performed one or more times, and are performed while the substrate is maintained at a temperature of 100° C. to 150° C.

[0026] In one embodiment, the thin film may be a tantalum nitride film.

[0027] In one embodiment, the substrate may include at least one of a silicon oxide film and a silicon nitride film.

[0028] In one embodiment, the substrate may include a stacked film in which silicon oxide films and silicon nitride films are alternately stacked in a vertical direction, and the tantalum nitride film is formed in an opening formed through the stacked film.

[0029] In one embodiment, the substrate may include: a stacked film, in which silicon oxide films and silicon nitride films are alternately stacked in a vertical direction; a first opening, in which the first opening is a slit shape formed by etching the stacked film in a vertical direction; and a plurality of second openings, formed by selectively etching the silicon nitride film exposed in the first opening and extending from the first opening in a horizontal direction, and the tantalum nitride film is formed on the first opening surface and the second opening surface.

[0030] In one embodiment, a tunneling oxide film may be formed along the first opening surface and the second opening surface, a nitride film well may be formed on the tunneling oxide film, a gate insulating film may be formed on the nitride film well, and the tantalum nitride film may be formed on the gate insulating film.

[0031] According to the present invention, the tantalum nitride film formed on the substrate can be modified by using the first gas containing oxygen (O), and the modified tantalum nitride film can be modified by using CHF 3 Gas is used to etch at atomic layer units.

[0032] In addition, by etching the tantalum nitride film in atomic layer units using such a gas, an excellent etching selectivity ratio with respect to the silicon oxide film and the silicon nitride film can be achieved, and the surface roughness of the etched tantalum nitride film can be reduced, and device failures caused by leakage current can be reduced.

[0033] However, the effects of the present invention are not limited to the effects mentioned above, and a person having ordinary knowledge in the technical field to which the present invention pertains can clearly understand other effects not mentioned from the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is a diagram showing a portion of a process for manufacturing 3D NAND flash memory.

[0035] Figure 2 The present invention is a flow chart of a substrate processing method according to an embodiment of the present invention.

[0036] Figure 3 This is a schematic cross-sectional view of a substrate processing apparatus according to an embodiment of the present invention.

[0037] Figure 4 FIG. 4 is a graph showing an etching rate according to a temperature of a substrate according to an embodiment of the present invention.

[0038] Figure 5 The graph is a graph showing the thickness of a tantalum oxide film modified according to one embodiment of the present invention measured according to temperature.

[0039] Figure 6 This is a graph showing the roughness of a substrate surface measured by etching according to one embodiment of the present invention.

[0040] Figure 7 A graph showing etching selectivity according to substrate types according to an embodiment of the present invention.

[0041] (Explanation of Reference Numerals)

[0042] 10: Substrate processing equipment

[0043] 100: Chamber

[0044] 200: Substrate support unit

[0045] 300: Plasma generating unit

[0046] 400: Gas supply unit

[0047] 500: Control unit DETAILED DESCRIPTION

[0048] Hereinafter, with reference to the attached drawings, the embodiments of the present invention will be described in detail so that a person with ordinary knowledge in the technical field to which the present invention belongs can easily implement it. However, the present invention can be implemented in various forms and is not limited to the embodiments described here.

[0049] When describing the embodiments of the present invention, when it is considered that a detailed description of a related well-known function or structure may unnecessarily obscure the gist of the present invention, the detailed description is omitted and the same symbols are used throughout the drawings for parts having similar functions and effects.

[0050] At least part of the terms used in the specification are defined in consideration of the functions of the present invention, and therefore may differ depending on the intentions of users and operators, practices, etc. Therefore, the terms should be interpreted based on the entire content of the specification.

[0051] In addition, in this specification, unless otherwise specified, the singular also includes the plural. In the specification, when any constituent element is included, it means that other constituent elements may be included, rather than excluding other constituent elements, unless there is a special description to the contrary.

[0052] On the other hand, in the drawings, the size or shape of components, the thickness of lines, and the like may be exaggerated for convenience of explanation.

[0053] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. When describing with reference to the accompanying drawings, the same or corresponding components are given the same reference numerals regardless of the figure numbers, and repeated descriptions thereof are omitted.

[0054] By using the substrate of an embodiment of the present invention as a silicon substrate to form a silicon oxide film or a silicon nitride film, a thin film can be formed on the silicon oxide film or the silicon nitride film. The thin film can be a tantalum nitride film, but is not limited thereto.

[0055] Figure 2 The present invention is a flow chart of a substrate processing method according to an embodiment of the present invention.

[0056] Reference Figure 2 , may be a method for etching a thin film formed on a substrate in atomic layer units, which includes: a surface modification step S10, supplying a first gas containing oxygen (O) to a processing space of a chamber configured with a substrate to modify the surface of the thin film; a first purge step S20, supplying a purge gas to the processing space to remove the first gas remaining in the processing space; an etching step S30, supplying CHF to the processing space 3 Gas to etch the modified film; and a second purge step S40, supplying purge gas to the processing space to remove CHF remaining in the processing space3 The surface modification step to the second purge step S10 to S40 may be regarded as one cycle and may be repeatedly performed one or more times to etch the thin film formed on the substrate to a desired thickness.

[0057] The surface modification step S10 is a step of supplying a first gas containing oxygen (O) to modify the surface of the thin film. The first gas containing oxygen (O) may be supplied in the gas supply unit, and the supplied first gas may be plasma-formed and supplied to the substrate. The plasma-formed first gas may chemically react with the thin film formed on the substrate to modify the surface layer of the thin film. The first gas may include O 2 , O 3 At least one of the following. The first gas according to one embodiment of the present invention is O 2 In the surface modification step S10, the surface of the tantalum nitride film formed on the silicon oxide film or the silicon nitride film can be modified in atomic layer or molecular layer units. As an example, the surface layer of the tantalum nitride film can be modified with plasma-activated O 2 The gas reacts and is modified into a tantalum oxide film (Ta x O y ).

[0058] The first purge step S20 is a step of supplying a purge gas in the gas supply unit to remove the first gas remaining in the processing space inside the chamber. The purge gas can be supplied after the supply of the first gas is interrupted, and can be immediately supplied to the processing space inside the chamber without using plasma. Due to the supply of the purge gas, the first gas and reaction byproducts remaining in the processing space inside the chamber supplied in the surface modification step S10 can be removed in the processing space. As the purge gas, argon (Ar), helium (He), nitrogen (N 2 ) and other inert gases.

[0059] The etching step S30 is to supply CHF 3 The etching step S30 may be a step of etching the modified thin film by plasma-forming CHF supplied in the gas supply unit. 3 gas, and etched modified to plasma CHF 3 The process of forming a thin film of gas. The CHF is radicalized and ionized by the plasma generating unit. 3 The gas can generate volatile etching byproducts by reacting with the surface of the modified film through ligand exchange reaction, and at the same time, the film formed on the substrate is etched in atomic layer or molecular layer units. According to the embodiment of the present invention, the tantalum oxide film modified by the surface modification step S10 can react with the plasma-generated CHF 3 The gas reacts to produce a volatile substance, namely tantalum fluoride (TaF x) and oxygen simultaneously etch in atomic or molecular layers. In addition, the remaining CHF after reacting with the modified tantalum oxide film 3 A portion of the gas can adhere to the surface layer of the tantalum nitride film to form fluorocarbon (C x F y ). Such fluorocarbon can be roughly formed on the surface layer of the tantalum nitride film, and then the fluorocarbon can be roughly formed on the surface layer of the tantalum nitride film by the oxygen (O 2 ) plasma and is removed.

[0060] The second purge step S40 is to supply a purge gas in the gas supply unit to remove CHF remaining in the processing space inside the chamber. 3 The purge gas can be used during the interruption of CHF 3 The purge gas is supplied after the etching step S30 and can be immediately supplied to the processing space inside the chamber without using plasma. Due to the supply of the purge gas, the CHF remaining in the processing space inside the chamber supplied in the etching step S30 can be removed. 3 Gases and etching byproducts are removed in the processing space. As purge gases, argon (Ar), helium (He), nitrogen (N 2 ) and other inert gases.

[0061] The substrate processing method according to an embodiment of the present invention may be performed by heating the substrate. The substrate may be heated by a heating member of a substrate supporting unit that supports the substrate, and the temperature of the substrate may be in a range of 100°C to 150°C.

[0062] Thus, in order to use the substrate processing method of the present invention to etch the thin film formed on the substrate, that is, the tantalum nitride film, in units of atomic layers, the first gas, that is, O 2 The tantalum nitride film formed on the substrate is modified by plasma and CHF is plasma 3 The modified tantalum nitride film is etched in atomic or molecular layers by using the gas.

[0063] Figure 3 FIG. 1 is a diagram showing a substrate processing apparatus according to an embodiment of the present invention.

[0064] Reference Figure 3 According to an embodiment of the present invention, a substrate processing apparatus 10 may include a chamber 100 , a substrate supporting unit 200 , a plasma generating unit 300 , a gas supply unit 400 , and a control unit 500 .

[0065] The chamber 100 has a space for performing a plasma process. The chamber 100 may be provided with an exhaust port 102 at its lower portion, and the exhaust port 102 may be connected to an exhaust line installed with a pump P. The exhaust port 102 may exhaust reaction byproducts generated during the plasma process and gas remaining inside the chamber 100 to the outside of the chamber 100 through the exhaust line. In this case, the internal space of the chamber 100 may be decompressed to a predetermined pressure.

[0066] The chamber 100 may have an opening 104 formed in a side wall thereof. The opening 104 may function as a passage for the substrate W to enter and exit the chamber 100. Such an opening 104 may be configured to be opened and closed by a door assembly.

[0067] The substrate support unit 200 may be disposed in the lower region of the chamber 100. The substrate support unit 200 may support the substrate W by electrostatic force. However, the present embodiment is not limited thereto, and the substrate may be supported by various methods such as mechanical clamping and vacuum.

[0068] The substrate support unit 200 may include a support body 210 and an electrostatic chuck 220 disposed on the support body 210. The electrostatic chuck 220 may be configured to electrostatically adsorb the substrate W, and may include a ceramic layer in which an electrode is inserted.

[0069] According to an embodiment of the present invention, a heating member 212 may be formed inside the support body 210. The heating member 212 may heat the substrate W to a set temperature, and may be, for example, a heating coil, but is not limited thereto.

[0070] A support member 230 for supporting the support member 210 and the electrostatic chuck 220 may be provided below the support member 210. The support member 230 may be in the shape of a cylinder having a predetermined height and may have a space therein.

[0071] The plasma generating unit 300 may generate plasma in the processing space of the chamber 100. The plasma may be formed in the upper region of the substrate supporting unit 200 in the chamber 100. According to an embodiment of the present invention, the plasma generating unit 300 may generate plasma in the processing space inside the chamber 100 using a capacitively coupled plasma (CCP) source.

[0072] However, the present embodiment is not limited thereto, and the plasma generating unit 300 may also generate plasma in the processing space inside the chamber 100 using other plasma sources such as an inductively coupled plasma (ICP) source or a microwave.

[0073] The plasma generating unit 300 may include a high frequency power source 302 and a matching device 304. The high frequency power source 302 may supply high frequency power to either the upper electrode or the lower electrode in order to generate a potential difference between the upper electrode and the lower electrode. Here, the upper electrode may be the showerhead 310, and the lower electrode may be the substrate supporting unit 200. The high frequency power source 302 may be connected to the lower electrode, and the upper electrode may be grounded.

[0074] The shower head 310 may be formed to face the electrostatic chuck 220 vertically in the chamber 100. Such a shower head 310 may be provided with a plurality of gas injection holes in order to uniformly inject gas into the chamber 100, and may be provided to have a larger diameter than the electrostatic chuck 220. On the other hand, the shower head 310 may be manufactured using either a silicon component or a metal component.

[0075] The gas supply unit 400 can supply the gas required for the process to the chamber 100. Such a gas supply unit 400 may include a gas supply source 402, a gas supply line 404, and a gas nozzle. The gas supply line 404 may connect the gas supply source 402 and the gas nozzle. A valve 406 may be provided on the gas supply line 404 to open or close its channel or to adjust the flow rate of the fluid flowing in its channel.

[0076] exist Figure 3 , one gas supply source 402 and a gas supply valve 406 are shown, but the gas supply source 402 of the present invention may include multiple gas supply sources and multiple gas supply valves capable of independently controlling the supply of each gas so that multiple gases can be supplied to the chamber 100. The multiple gases used for modifying the substrate W or etching the modified substrate W may include, for example, a first gas for modifying the surface of a thin film formed on the substrate W, a second gas for etching the modified thin film, and an inert gas for purging. The first gas may include, as a gas containing oxygen (O), O 2 , O 3 In any one of the above, the second gas may be CHF as a gas containing fluorine (F). 3 .

[0077] The control unit 500 can fully control the operation of the substrate processing apparatus 10 configured as described above. As an example, the control unit 500 can be a computer, which has a central processing unit (CPU), a random access memory (RAM), a read-only memory (ROM), an auxiliary memory, etc. The CPU can operate based on the program or process conditions stored in the ROM or the auxiliary memory and control the overall operation of the substrate processing apparatus 10.

[0078] The control unit 500 according to an embodiment of the present invention can control the supply of the first gas and the second gas to the processing space inside the chamber 100, and plasmatize the first gas and the second gas through the plasma generating unit 300. In addition, the control unit 500 can control the heating member 212 of the substrate supporting unit 200 to control the temperature of the substrate W.

[0079] Next, we explain how to use Figure 3 An experimental example of using a substrate processing device to perform an atomic layer etching process. Figures 4 to 7 This is a graph of an experimental example of an embodiment of the present invention.

[0080] According to an experimental example of an embodiment of the present invention, a silicon oxide film of about 200 nm is formed on a silicon substrate, and a tantalum nitride film of about 50 nm is formed on the silicon oxide film to perform an etching process.

[0081] Figure 4 is a graph showing an etching rate according to a temperature of a substrate by an embodiment of the present invention, Figure 5 This is a graph showing the thickness of the modified tantalum oxide film measured according to the temperature during the etching process. In order to confirm the etching rate of the tantalum nitride film according to the temperature of the substrate, the etching rate according to the temperature was measured while changing the temperature of the substrate from 0°C to 300°C under the conditions of [Table 1] below. At this time, the etching process was performed 10 cycles according to the temperature of the substrate.

[0082]

Table 1

[0083]

[0084] Reference Figure 4 , when the temperature of the substrate is 0° C. to 25° C., the tantalum nitride film is not etched.

[0085] When the substrate temperature is 50°C, the tantalum nitride film is etched very finely. At this time, the etching amount is about degree.

[0086] When the substrate temperature is 100°C, the etching amount of the tantalum nitride film is about

[0087]

[0088] When the substrate temperature is 150°C, the etching amount of the tantalum nitride film is about

[0089]

[0090] When the substrate temperature is 200°C, the etching amount of the tantalum nitride film is about

[0091]

[0092] When the substrate temperature is 250°C, the etching amount of the tantalum nitride film is about

[0093]

[0094] When the substrate temperature is 300°C, the etching amount of the tantalum nitride film is about

[0095]

[0096] That is, it can be seen that the etching rate of the tantalum nitride film continues to increase according to the temperature. Figure 5 As shown, the tantalum nitride film is subjected to the first gas, namely, O 2 During the process of transformation into tantalum oxide film, the surface layer of tantalum nitride film did not reach saturation with the change of temperature, and the thickness of tantalum oxide film continued to increase, which may be one of the reasons.

[0097] Based on the above experimental results, it is preferable to etch the tantalum nitride film at a temperature of 100°C to 150°C where the etching rate can be easily controlled. The etching rate is very small at a temperature below 100°C, and at a temperature above 150°C, the etching rate changes greatly according to the temperature change, making it difficult to control the etching rate.

[0098] Figure 6 This is a graph showing the surface roughness of the tantalum nitride film measured for each etching cycle. In order to measure the roughness of the etched tantalum nitride film, the tantalum nitride film was etched under the conditions shown in Table 2 below.

[0099]

Table 2

[0100]

[0101] In order to measure the surface roughness of the tantalum nitride film, the root mean square roughness was measured using AFM (Atomic Force Microscopy).

[0102] Reference Figure 6 In the case of a tantalum nitride film without an etching process on the substrate, the surface roughness is about 0.75 nm.

[0103] When the etching process was performed for 5 cycles under the conditions of [Table 2], the surface roughness of the etched tantalum nitride film was about 0.35 nm.

[0104] It can be seen that when the etching process is performed for 10 cycles, the surface roughness of the etched tantalum nitride film is about 0.25 nm, and when the etching process is performed for 20 cycles, the surface roughness of the etched tantalum nitride film is about 0.23 nm.

[0105] That is, in the case of the etched tantalum nitride film, it can be seen that the surface roughness decreases by about 3% per cycle, which means that the surface of the etched tantalum nitride film is uniform.

[0106] Figure 7 1 is a graph showing the etching selectivity ratio according to the substrate type. According to one embodiment of the present invention, the substrate may include a silicon oxide film or a silicon nitride film, and a tantalum nitride film may be formed on the silicon oxide film or the silicon nitride film. According to one embodiment of the present invention, the etching process is performed by forming a silicon nitride film of about 200 nm on a silicon substrate and a tantalum nitride film of about 50 nm on the silicon nitride film.

[0107] In order to confirm the etching selectivity of the tantalum nitride film formed on the silicon oxide film and the etching selectivity of the tantalum nitride film formed on the silicon nitride film, after performing 10 cycles under the conditions of the above-mentioned [Table 2], the etching selectivity according to the type of substrate was confirmed.

[0108] Reference Figure 7 In the case of a tantalum nitride film formed on a silicon oxide film, the etching selectivity to the silicon oxide film is 3.8. In addition, it can be known that in the case of tantalum formed on a silicon nitride film, the etching selectivity to the silicon nitride film is 2. This means that by the etching method of the embodiment of the present invention, the etching of the silicon oxide film or the silicon nitride film can be minimized while selectively etching the tantalum nitride film.

[0109] From such experimental results, it can be seen that in order to etch the tantalum nitride film formed on the silicon oxide film or the silicon nitride film, the tantalum nitride film is modified with the first gas containing oxygen (O) and the CHF 3 The gas etches the modified tantalum nitride film in atomic layer units.

[0110] In addition, using the first gas and CHF 3 gas, thereby reducing the surface roughness of the tantalum nitride film and reducing device defects caused by leakage current.

[0111] Furthermore, compared with silicon oxide films and silicon nitride films, tantalum nitride films can be selectively etched, thereby achieving excellent etching selectivity. Based on this, it can be applied to various processes.

[0112] The above description is only an example of the technical concept of the present invention. Anyone with common knowledge in the technical field to which the present invention belongs can make various modifications and deformations without departing from the essential characteristics of the present invention. Therefore, the embodiments recorded in the present invention are not intended to limit the technical concept of the present invention, but to illustrate the technical concept of the present invention, and the technical concept of the present invention is not limited to these embodiments. The protection scope of the present invention should be interpreted according to the attached claims, and all technical concepts within the equivalent scope should be interpreted as included in the scope of the rights of the present invention.

Claims

1. A substrate processing method for etching a thin film formed on a substrate in atomic layer units, It is characterized in that The substrate processing method comprises: a surface modification step of supplying a first gas containing oxygen to a processing space of a chamber in which the substrate is disposed to modify the surface of the thin film; a first purge step of supplying a purge gas to the processing space to remove the first gas remaining in the processing space; Etching step, supplying CHF to the processing space 3 Gas to etch the modified film; and The second purge step is to supply purge gas to the processing space to remove the CHF remaining in the processing space. 3 gas.

2. The substrate processing method according to claim 1, It is characterized in that The cycle including the surface modification step to the second purge step is repeatedly performed one or more times.

3. The substrate processing method according to claim 1, It is characterized in that The thin film is a tantalum nitride film.

4. The substrate processing method according to claim 3, It is characterized in that The substrate includes at least any one of a silicon oxide film and a silicon nitride film.

5. The substrate processing method according to claim 4, It is characterized in that The substrate includes a laminated film in which silicon oxide films and silicon nitride films are alternately laminated. The tantalum nitride film is formed in an opening formed through the stacked film.

6. The substrate processing method according to claim 1, It is characterized in that The first gas comprises O 2 , O 3 At least one of .

7. The substrate processing method according to claim 1, It is characterized in that The surface modification step and the etching step are performed in a state where plasma is generated in the processing space.

8. The substrate processing method according to claim 1, It is characterized in that The surface modification step to the second purge step are performed in a state where the substrate is heated to a predetermined temperature.

9. The substrate processing method according to claim 8, It is characterized in that The predetermined temperature is 100°C to 150°C.

10. A substrate processing device, It is characterized in that include: a chamber having a processing space therein; a substrate supporting unit disposed in the processing space and comprising a heating component for heating the substrate while supporting the substrate; A gas supply unit for supplying a first gas containing oxygen and CHF to the processing space 3 gas; a plasma generating unit for plasma-forming the gas supplied from the gas supply unit; as well as a control unit, configured to control the gas supply unit and the plasma generating unit, The control unit controls the gas supply unit and the plasma generating unit to generate plasma of the first gas in the processing space to modify the thin film formed on the substrate and generate the CHF 3 The modified thin film formed on the substrate is etched by the gas plasma.

11. The substrate processing apparatus according to claim 10, It is characterized in that The thin film is a tantalum nitride film.

12. The substrate processing apparatus according to claim 10, It is characterized in that The first gas comprises O 2 , O 3 At least one of .

13. The substrate processing apparatus according to claim 11, It is characterized in that The substrate includes a laminated film in which silicon oxide films and silicon nitride films are alternately laminated. The tantalum nitride film is formed in an opening formed through the stacked film.

14. The substrate processing apparatus according to claim 10, It is characterized in that The control unit controls the heating member to maintain the temperature of the substrate at 100° C. to 150° C.

15. A substrate processing method for etching a thin film formed on a substrate for manufacturing a 3D NAND device in units of atomic layers, It is characterized in that The substrate processing method comprises: a surface modification step of supplying a first gas containing oxygen to a processing space of a chamber in which the substrate is disposed to modify the surface of the thin film; a first purge step of supplying a purge gas to the processing space to remove the first gas remaining in the processing space; Etching step, supplying CHF to the processing space 3 and etching the modified thin film; and The second purge step is to supply purge gas to the processing space to remove the CHF remaining in the processing space. 3 gas; The first gas comprises O 2 , O 3 At least one of The surface modification step to the second purge step constitute one cycle and are repeatedly performed one or more times, and are performed while the substrate is maintained at a temperature of 100° C. to 150° C.

16. The substrate processing method according to claim 15, It is characterized in that The thin film is a tantalum nitride film.

17. The substrate processing method according to claim 16, It is characterized in that The substrate includes at least any one of a silicon oxide film and a silicon nitride film.

18. The substrate processing method according to claim 17, It is characterized in that The substrate includes a stacked film in which silicon oxide films and silicon nitride films are alternately stacked in a vertical direction. The tantalum nitride film is formed in an opening formed through the stacked film.

19. The substrate processing method according to claim 17, It is characterized in that The substrate comprises: A stacked film, wherein silicon oxide films and silicon nitride films are alternately stacked in a vertical direction; a first opening having a slit shape formed by etching the stacked film in a vertical direction; and a plurality of second openings are formed by selectively etching the silicon nitride film exposed in the first openings and extending from the first openings in a horizontal direction, The tantalum nitride film is formed on the first opening surface and the second opening surface.

20. The substrate processing method according to claim 19, It is characterized in that forming a tunnel oxide film along the first opening surface and the second opening surface, forming a nitride film well on the tunnel oxide film, forming a gate insulating film on the nitride film well, The tantalum nitride film is formed on the gate insulating film.

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