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 (Cl) 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 etching the modified thin film by supplying a second gas containing acetylacetone to the processing space; and a second purge step of supplying a purge gas to the processing space to remove the second 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 cobalt 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] The gate allows current to flow to the element according to the voltage applied to the gate, and mainly uses metal materials. Cobalt is used as the material constituting such a gate. Usually, after the cobalt is completely evaporated in the opening portion where the gate insulating layer and the barrier layer are formed, in order to make the evaporated film uniform, the cobalt film is etched using an etching process.

[0006] Such a cobalt film is etched using an atomic layer etching method. Non-patent document 1 proposes a method of modifying a cobalt film using chlorine (Cl) gas and etching the modified cobalt film in atomic layer units using hexafluoroacetylacetone (Hhfac). In the case of hexafluoroacetylacetone (Hhfac) proposed in non-patent document 1, it is a very expensive substance, so if it is used to manufacture 3D NAND flash memory, there is a problem of increasing the manufacturing unit price of the element.

[0007] (Non-patent document 1) Mahsa Konh, Molecular mechanisms of atomic layer etchingof cobalt with sequential exposure to molecular chlorine and diketones, Journal of Vacuum Science Technology A, 2019, 37(2), pages 021004-1 to 021004-8 Summary of the invention

[0008] In order to solve the problems of the prior art, the present invention provides a substrate processing method and a substrate processing device for reducing the manufacturing unit price of a component.

[0009] 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.

[0010] It may be that a method for etching a thin film formed on a substrate in atomic layer units according to an embodiment of the present invention includes: a surface modification step of supplying a first gas containing chlorine (Cl) 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 a second gas containing acetylacetone 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 second gas remaining in the processing space.

[0011] In one embodiment, the cycle including the surface modification step to the second purge step may be repeated one or more times.

[0012] In one embodiment, the thin film may be a cobalt film.

[0013] In one embodiment, the substrate may include at least one of a silicon oxide film and a silicon nitride film.

[0014] In one embodiment, the substrate may include a stacked film in which silicon oxide films and silicon nitride films are alternately stacked, and the cobalt film may be formed in an opening formed through the stacked film.

[0015] In one embodiment, the first gas may be Cl 2 , the second gas is a mixed gas of acetylacetone and nitrogen.

[0016] In one embodiment, the surface modification step may be performed in a state where plasma of the first gas is generated in the processing space.

[0017] 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.

[0018] In one embodiment, the predetermined temperature may be 125°C to 175°C.

[0019] It may be that a substrate processing device according to an embodiment of the present invention includes: a chamber having a processing space therein; a substrate supporting unit, which is arranged in the processing space and includes a heating component for heating the substrate while supporting the substrate; a gas supply unit, which is used to supply a first gas containing chlorine (Cl) and a second gas containing acetylacetone to the processing space; a plasma generating unit, which is used to plasmatize the gas supplied from the gas supply unit; and a control unit, which is used to control 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 supplying the second gas to the processing space to etch the modified thin film formed on the substrate.

[0020] In one embodiment, the thin film may be a cobalt film.

[0021] In one embodiment, the cobalt film may be formed on a silicon oxide film or a silicon nitride film.

[0022] In one embodiment, the first gas may be Cl 2 , the second gas is a mixed gas of acetylacetone and nitrogen.

[0023] In one embodiment, the control unit may control the heating component to maintain the temperature of the substrate at 125° C. to 175° C.

[0024] The method for etching a thin film formed on a substrate for manufacturing a 3D NAND device in atomic layer units according to an embodiment of the present invention includes: a surface modification step of supplying a first gas containing chlorine (Cl) 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 a second gas containing acetylacetone 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 second gas remaining in the processing space, wherein the first gas is Cl 2 The second gas is a mixed gas of acetylacetone and nitrogen, the surface modification step to the second purge step constitute a cycle and are repeated more than once, and are performed while maintaining the substrate at a temperature of 125° C. to 175° C.

[0025] In one embodiment, the thin film may be a cobalt film.

[0026] In one embodiment, the substrate may include at least one of a silicon oxide film and a silicon nitride film.

[0027] 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 cobalt film is formed in an opening formed through the stacked 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; a first opening, which is a slit shape formed by etching the stacked film in a vertical direction; and a plurality of second openings, which are 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 cobalt film is formed on the first opening surface and the second opening surface.

[0029] In one embodiment, a tunnel oxide film (Tunneling oxide) may be formed along the first opening surface and the second opening surface, a nitride film well may be formed on the tunnel oxide film, a gate insulating film may be formed on the nitride film well, a barrier layer may be formed on the gate insulating film, and the cobalt film may be formed on the barrier layer.

[0030] According to the present invention, a thin film formed on a substrate is modified by using a first gas containing chlorine (Cl) and a second gas containing acetylacetone to etch the modified thin film in atomic layer units, thereby reducing the manufacturing unit cost.

[0031] Furthermore, by etching the cobalt film in atomic layer units using such a gas, the surface roughness of the etched cobalt film can be reduced, thereby reducing defects in semiconductor devices.

[0032] 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

[0033] Figure 1 is a diagram showing a portion of a process for manufacturing 3D NAND flash memory.

[0034] Figure 2 The present invention is a flow chart of a substrate processing method according to an embodiment of the present invention.

[0035] Figure 3 This is a schematic cross-sectional view of a substrate processing apparatus according to an embodiment of the present invention.

[0036] 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.

[0037] Figure 5 This is a graph showing the roughness of a substrate surface measured by etching according to one embodiment of the present invention.

[0038] Figure 6 FIG. 4 is a graph showing an etching selectivity ratio according to a substrate type according to an embodiment of the present invention.

[0039] (Explanation of Reference Numerals)

[0040] 10: Substrate processing equipment

[0041] 100: Chamber

[0042] 200: Substrate support unit

[0043] 300: Plasma generating unit

[0044] 400: Gas supply unit

[0045] 500: Control unit DETAILED DESCRIPTION

[0046] 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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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 cobalt film, but is not limited thereto.

[0053] Figure 2 The present invention is a flow chart of a substrate processing method according to an embodiment of the present invention.

[0054] 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 chlorine (Cl) to a processing space of a chamber in which a substrate is arranged 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 a second gas containing acetylacetone (Acetylacetone; Hacac) to the processing space to etch the modified thin film; and a second purge step S40, supplying a purge gas to the processing space to remove the second gas remaining in the processing space. The surface modification step to the second purge step S10-S40 may be regarded as one cycle, and may be repeated more than once to etch the thin film formed on the substrate to a desired thickness.

[0055] The surface modification step S10 is a step of supplying a first gas containing chlorine (Cl) to modify the surface of the thin film. The first gas containing chlorine (Cl) 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. In one embodiment of the present invention, the first gas is Cl 2 The first gas may be supplied to the processing space of the chamber during a predetermined time. In the surface modification step S10, the surface of the cobalt film formed on the silicon oxide film or the silicon nitride film may be modified in atomic or molecular layers. For example, the surface layer of the cobalt film may be modified with the plasma-generated Cl 2 The gas reacts and is modified into cobalt chloride (CoCl x )membrane.

[0056] 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 from the processing space. As the purge gas, argon (Ar), helium (He), nitrogen (N 2 ) and other inert gases.

[0057] The etching step S30 is a step of supplying a second gas containing acetylacetone to etch the modified film. The second gas containing acetylacetone may be supplied in the gas supply unit to etch the modified film. The second gas according to one embodiment of the present invention may be acetylacetone and nitrogen (N 2 ) mixed with a gas. Such a gas may be supplied to the processing space of the chamber during a predetermined time. Acetylacetone may react with the surface of the film modified by the surface modification step S10 to produce volatile etching byproducts while etching the surface layer of the modified film. According to one embodiment of the present invention, the cobalt chloride film modified by the surface modification step S10 may react with acetylacetone to produce a volatile substance, namely, acetylacetonate cobalt chloride (Co(acac) x Cl y ) and hydrogen chloride (HCl) are used simultaneously to etch in atomic or molecular layers.

[0058] The second purge step S40 is a step of supplying a purge gas in the gas supply unit to remove the second gas remaining in the processing space inside the chamber. The purge gas can be supplied after the supply of the second 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 second gas and etching byproducts remaining in the processing space inside the chamber supplied in the etching step S30 can be removed in the processing space. As the purge gas, argon (Ar), helium (He), nitrogen (N 2 ) and other inert gases.

[0059] 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 125°C to 175°C.

[0060] Thus, in order to etch the thin film formed on the substrate, that is, the cobalt film, in units of atomic layers using the substrate processing method of the present invention, the first gas, that is, Cl 2 The cobalt film formed on the substrate is modified by plasma, and the modified cobalt film is etched in atomic or molecular layers by supplying a second gas containing acetylacetone. Using such a substrate processing method, acetylacetone is about 10 times cheaper than hexafluoroacetylacetone (Hhfac) used in the past, so the manufacturing unit price of the device can be reduced.

[0061] Figure 3 FIG. 1 is a diagram showing a substrate processing apparatus according to an embodiment of the present invention.

[0062] 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 .

[0063] 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.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] 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 be a gas containing chlorine (Cl), which may be Cl 2 The second gas may be a mixed gas of acetylacetone and nitrogen, but is not limited thereto.

[0074] 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.

[0075] The control unit 500 according to an embodiment of the present invention can control the first gas to be supplied to the processing space inside the chamber 100, and the first gas can be plasmatized by the plasma generating unit 300. In addition, the control unit 500 can control the temperature of the substrate W to be maintained in the range of 125° C. to 175° C. during the etching process by controlling the heating member 212 of the substrate supporting unit 200.

[0076] 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 6 This is a graph of an experimental example of an embodiment of the present invention.

[0077] 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 cobalt film of about 50 nm is formed on the silicon oxide film to perform an etching process.

[0078] Figure 4 This is a graph showing the etching rate according to the temperature of the substrate according to one embodiment of the present invention. In order to confirm the thickness of the cobalt film etched according to the temperature of the substrate, the etching amount per cycle was measured according to the temperature while the temperature of the substrate was changed from 25°C to 250°C under the conditions of [Table 1] below. At this time, the etching process was performed for 30 cycles according to the temperature of the substrate.

[0079]

Table 1

[0080]

[0081] Reference Figure 4 , when the temperature of the substrate is 25° C. to 100° C., the cobalt film is not etched. In more detail, the first gas containing chlorine (Cl) reacts with the cobalt film to be modified into a cobalt chloride film, or the temperature of the substrate is low and acetylacetone does not react with the modified cobalt chloride film and is adsorbed on the modified cobalt chloride film.

[0082] When the substrate temperature is 125°C, the etching amount of the cobalt film is about

[0083] When the substrate temperature is 150°C, the etching amount of the cobalt film is about

[0084] When the substrate temperature is 175°C, the etching amount of the cobalt film is about

[0085] When the substrate temperature is 200°C or 250°C, the etching amount of the cobalt film is about This may be because the first gas containing chlorine reacts with the cobalt film to modify it into a cobalt chloride film, or because the temperature of the substrate is increased to decompose acetylacetone. That is, the amount of acetylacetone used to etch the modified cobalt chloride film is insufficient, and therefore the etching amount per cycle is significantly reduced.

[0086] Based on such experimental results, it can be known that etching the cobalt film is most preferable when the substrate has a temperature range of 125° C. to 175° C. Therefore, when etching the cobalt film at 125° C. to 175° C., the controllability of the etching process can be improved, and the etching amount per cycle can be increased, so the etching rate can be increased.

[0087] Figure 5 This is a graph showing the surface roughness of the cobalt film measured for each etching cycle. The surface roughness of the etched cobalt film was measured under the conditions shown in Table 2 below.

[0088]

Table 2

[0089]

[0090] In order to measure the surface roughness of the cobalt film, the root mean square roughness was measured using AFM (Atomic Force Microscope).

[0091] Reference Figure 5 , in the case of the cobalt film without performing an etching process on the substrate, the surface roughness is about 6.5 nm.

[0092] When the 5-cycle etching process is performed under the above-mentioned conditions, the surface roughness of the etched cobalt film is about 1.5 nm.

[0093] In the case where the etching process was performed for 10 cycles, the surface roughness of the etched cobalt film was about 1 nm.

[0094] In the case where the etching process was performed for 20 cycles, the surface roughness of the etched cobalt film was about 0.8 nm.

[0095] That is, in the case of the etched cobalt film, it can be seen that the surface roughness is reduced by about 6% per cycle, which means that the surface of the etched cobalt film is uniform.

[0096] Figure 6 2 is a graph showing etching selectivity according to the type of substrate. According to an embodiment of the present invention, the substrate may include a silicon oxide film or a silicon nitride film, and a cobalt film may be formed on the silicon oxide film or the silicon nitride film.

[0097] According to an experimental example of an embodiment of the present invention, a silicon nitride film with a thickness of about 200 nm is formed on a silicon substrate, and a cobalt film with a thickness of about 50 nm is formed on the silicon nitride film to perform an etching process.

[0098] In order to confirm the etching selectivity of the cobalt film formed on the silicon oxide film and the etching selectivity of the cobalt film formed on the silicon nitride film, after performing 15 cycles under the conditions of the above-mentioned [Table 2], the etching selectivity depending on the type of substrate was confirmed.

[0099] Reference Figure 6 In the case of a cobalt film formed on a silicon oxide film, the etching selectivity ratio with respect to the silicon oxide film is infinite. In addition, in the case of a cobalt film formed on a silicon nitride film, the etching selectivity ratio with respect to the silicon nitride film is infinite. This is a case where the cobalt film is etched, but the silicon oxide film and the silicon nitride film are not etched. Through the embodiments of the present invention, it can be known that the cobalt film can be etched with a high etching selectivity compared to the silicon oxide film or the silicon nitride film.

[0100] From such experimental results, it can be seen that in order to etch a cobalt film formed on a silicon oxide film or a silicon nitride film, the cobalt film is modified by using a first gas containing chlorine (Cl), and the modified cobalt film is etched using a second gas containing acetylacetone, thereby significantly reducing the manufacturing unit price of the component compared to the past.

[0101] In addition, by using such a first gas and a second gas, the surface roughness of the etched cobalt film can be reduced and device failure due to leakage current can be reduced.

[0102] In addition, cobalt films can be selectively etched compared to silicon oxide films and silicon nitride films, thus achieving excellent etching selectivity, which makes it applicable to various processes.

[0103] 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 chlorine 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; an etching step of supplying a second gas containing acetylacetone to the processing space to etch the modified thin film; and The second purge step is to supply a purge gas to the processing space to remove the second gas remaining in the processing space.

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 cobalt 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 cobalt 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 is Cl 2 , the second gas is a mixed gas of acetylacetone and nitrogen.

7. The substrate processing method according to claim 1, It is characterized in that The surface modification step is performed in a state where plasma of the first gas 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 125°C to 175°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 chlorine and a second gas containing acetylacetone to the processing space; 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 supplies the second gas to the processing space to etch the modified thin film formed on the substrate.

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

12. The substrate processing apparatus according to claim 11, It is characterized in that The cobalt film is formed on a silicon oxide film or a silicon nitride film.

13. The substrate processing apparatus according to claim 10, It is characterized in that The first gas is Cl 2 , The second gas is a mixed gas of acetylacetone and nitrogen.

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 125° C. to 175° 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 chlorine 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; an etching step of supplying a second gas containing acetylacetone 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 second gas remaining in the processing space; The first gas is Cl 2 , the second gas is a mixed gas of acetylacetone and nitrogen, 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 125° C. to 175° C.

16. The substrate processing method according to claim 15, It is characterized in that The thin film is a cobalt 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 cobalt 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 having silicon oxide films and silicon nitride films 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 cobalt 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, forming a barrier layer on the gate insulating film, The cobalt film is formed on the barrier layer.

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