Substrate processing method and substrate processing device

Abstract

Provided are a substrate processing method and a film formation device which perform selective etching on a film of a layered material.　The present invention provides a substrate processing method comprising a step for emitting particles to a substrate on which a film of a layered material is formed and etching the film of the layered material.

Description

Substrate processing method and substrate processing apparatus

[0001] The present disclosure relates to a substrate processing method and a substrate processing apparatus.

[0002] Various two-dimensional materials are attracting attention as semiconductor materials to replace silicon. ２ ), and graphene are known. Due to the unique two-dimensional structure of two-dimensional materials, they have distinctive electrical properties such as high electron mobility. For this reason, transition metal dichalcogenides and their laminated films are expected to be used not only as materials for forming, for example, transistor channel layers, transparent conductive films, and wiring, but also as key materials for electronic devices such as high-frequency devices and sensors. Patent Document 1 discloses a method for forming a film of a transition metal dichalcogenide, which is one type of two-dimensional material, using an atomic layer deposition (ALD) process.

[0003] Japanese Patent Application Laid-Open No. 2022-101619

[0004] In one aspect, the present disclosure provides a substrate processing method and deposition apparatus for selectively etching a film of a layered material.

[0005] In order to solve the above problem, according to one aspect, there is provided a substrate processing method comprising the step of irradiating particles onto a substrate on which a film of a layered material has been formed, thereby etching the film of the layered material.

[0006] According to one aspect, the present disclosure can provide a substrate processing method and a film forming apparatus for selectively etching a film of a layered material.

[0007] An example of a configuration diagram of a substrate processing apparatus according to an embodiment. An example of a configuration diagram of an etching apparatus according to an embodiment. A flowchart showing an example of a substrate processing method according to an embodiment. An example of a cross-sectional view of a substrate W at each step in a substrate processing method according to an embodiment. An example of a cross-sectional view of a substrate W at each step in a substrate processing method according to an embodiment. An example of a cross-sectional view of a substrate W at each step in a substrate processing method according to an embodiment. An example of a schematic view showing bond energy in a film of a layered material. An example of a cross-sectional view of a substrate showing the incident direction of particles. An example of a cross-sectional view of a substrate showing the incident direction of particles.

[0008] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals, and redundant explanations may be omitted.

[0009] [Processing System] A substrate processing apparatus 100 used in a substrate processing method according to an embodiment will be described with reference to Fig. 1. Fig. 1 is an example of a configuration diagram of the substrate processing apparatus 100 according to an embodiment.

[0010] The substrate processing apparatus 100 includes processing chambers 101 to 104 , a vacuum transfer chamber 105 , load lock chambers 301 to 303 , an atmospheric transfer chamber 400 , load ports 501 to 504 , and a control device 600 .

[0011] The processing chambers 101 to 104 are connected to a vacuum transfer chamber 105 via gate valves G11 to G14, respectively. The processing chambers 101 to 104 are depressurized to a predetermined vacuum atmosphere, and the substrates W are subjected to desired processing therein.

[0012] The processing chamber 101 is a film forming apparatus that performs step S102 in FIG. 3, which will be described later, to form a film 210 of a layer material on a substrate W (see FIG. 4A, etc., which will be described later).

[0013] Here, a layered material is a two-dimensional material (2D material) in which atoms are bonded in a sheet-like manner. Examples of layered materials include chalcogenides and graphene. Among layered materials, chalcogenides are substances in which a metal element M is bonded to a chalcogen element X. Examples of the metal element M include, but are not limited to, molybdenum (Mo), tungsten (W), bismuth (Bi), antimony (Sb), tin (Sn), germanium (Ge), etc. Examples of the chalcogen element X include, but are not limited to, sulfur (S), selenium (Se), tellurium (Te), etc.

[0014] The processing chamber 101 may be, for example, an ALD (Atomic Layer Deposition) apparatus. The processing chamber 101, which is an ALD apparatus, includes a substrate support (not shown) capable of supporting a substrate W, a processing vessel (not shown) that houses the substrate support, and a gas supply unit (not shown) that supplies process gases (source gas, reactive gas, etc.) into the processing vessel. A predetermined vacuum atmosphere is created inside the processing vessel. The processing chamber 101 forms a layer material film 210 on the substrate W by alternately supplying source gas and reactive gas from the gas supply unit into the processing vessel. Note that the processing chamber 101 may perform pre-processing or post-processing on the substrate by supplying a process gas into the processing vessel. The processing chamber 101 may also be a thermal ALD apparatus or a plasma ALD apparatus.

[0015] The processing chamber 101 may also be, for example, a CVD (Chemical Vapor Deposition) apparatus. The processing chamber 101, which is a CVD apparatus, includes a substrate support (not shown) capable of supporting a substrate W, a processing vessel (not shown) that houses the substrate support, and a gas supply unit (not shown) that supplies process gases (source gas, reactive gas, etc.) into the processing vessel. A predetermined vacuum atmosphere is created inside the processing vessel. The processing chamber 101 forms a layer material film 210 on the substrate W by simultaneously supplying a source gas and a reactive gas from the gas supply unit into the processing vessel. The processing chamber 101 may also perform pre-processing or post-processing on the substrate by supplying a process gas into the processing vessel. The processing chamber 101 may also be a thermal CVD apparatus or a plasma CVD apparatus.

[0016] The processing chamber 101 may also be, for example, a physical vapor deposition (PVD) apparatus. The processing chamber 101, which is a PVD apparatus, includes a substrate support (not shown) capable of supporting a substrate W, a processing vessel (not shown) that houses the substrate support, and a target (not shown) containing a layer material provided in the processing vessel. A predetermined vacuum atmosphere is created inside the processing vessel. The processing chamber 101 emits sputtered particles from the target containing the layer material to form a film 210 of the layer material on the substrate W. The PVD apparatus may also be an apparatus that combines RF sputtering, DC sputtering, ion beam sputtering, etc. with a multi-cathode and is capable of performing a film formation process by selecting from multiple sources.

[0017] Although the processing chamber 101 has been described as being either an ALD apparatus, a CVD apparatus, or a PVD apparatus, it is not limited to these and may also be a film formation apparatus that forms a film 210 of layered material on the substrate W using other methods.

[0018] 2, which will be described later, to selectively etch the layer material film 210. The configuration of the processing chamber 102 will be described later with reference to FIG.

[0019] The processing chambers 103 and 104 may be processing chambers that perform the same processing process as any of the processing chambers 101 and 102, or processing chambers that perform a processing process different from any of the processing chambers 101 and 102 (for example, an annealing device, a substrate pre-processing device such as UV ozone, a film forming device for forming electrodes or gate insulating films, etc.).

[0020] The interior of the vacuum transfer chamber 105 is depressurized to a predetermined vacuum atmosphere. The vacuum transfer chamber 105 is an example of a transfer device that transfers the substrate W. The vacuum transfer chamber 105 is provided with a transfer mechanism 106 that can transfer the substrate W in a depressurized state. The transfer mechanism 106 transfers the substrate W to the processing chambers 101 to 104 and the load lock chambers 301 to 303.

[0021] The load lock chambers 301 to 303 are connected to the vacuum transfer chamber 105 via gate valves G21 to G23, respectively, and are connected to the atmospheric transfer chamber 400 via gate valves G31 to G33. The interiors of the load lock chambers 301 to 303 can be switched between an atmospheric atmosphere and a vacuum atmosphere.

[0022] The atmospheric transfer chamber 400 has an atmospheric atmosphere, and for example, a downflow of clean air is formed. An aligner (not shown) that aligns the substrate W is provided inside the atmospheric transfer chamber 400. A transfer mechanism 402 is also provided in the atmospheric transfer chamber 400. The transfer mechanism 402 transfers the substrate W to the load lock chambers 301 to 303 and the carriers C and aligners of the load ports 501 to 504, which will be described later.

[0023] The load ports 501 to 504 are provided on the wall surface of the atmospheric transfer chamber 400. Carriers C containing substrates W or empty carriers C are attached to the load ports 501 to 504 via gate valves G41 to G44. As the carriers C, for example, FOUPs (Front Opening Unified Pods) can be used.

[0024] The control device 600 controls each part of the substrate processing apparatus 100. For example, the control device 600 executes the operations of the processing chambers 101 to 104, the operation of the transfer mechanisms 106 and 402, the opening and closing of the gate valves G11 to G14, G21 to G23, G31 to G33, and G41 to G44, and the switching of the atmospheres in the load lock chambers 301 to 303.

[0025] Next, the processing chamber 102 as an etching apparatus that selectively etches the layer material film 210 will be described with reference to Fig. 2. Fig. 2 is an example of a configuration diagram of an etching apparatus (processing chamber 102) according to one embodiment. The etching apparatus (processing chamber 102) shown in Fig. 2 is a gas cluster ion beam irradiation apparatus, and is an apparatus that can irradiate the surface of the substrate W with a gas cluster ion beam (GCIB).

[0026] The processing chamber 102 serving as a gas cluster ion beam irradiation device has a nozzle chamber 20, a source chamber 30, and a main chamber 40. The nozzle chamber 20, the source chamber 30, and the main chamber 40 are evacuated (indicated by the outlined arrows in FIG. 2) by an exhaust device (not shown), and the interiors thereof are kept at a predetermined vacuum atmosphere.

[0027] The nozzle chamber 20 has a nozzle 21 for generating gas clusters and a skimmer 22 for sorting the generated gas clusters.

[0028] The nozzle 21 is connected to a gas supply unit 23, and a source gas for generating gas clusters is supplied to the nozzle 21 from the gas supply unit 23. The gas supply unit 23 is provided with a plurality of gas supply sources so as to be able to supply a plurality of source gases. Specifically, as shown in FIG. 2, a first gas supply source 24 and a second gas supply source 25, such as gas cylinders containing source gases, are provided, and a valve 26 provided in the gas supply unit 23 is configured to be able to supply a predetermined amount of the source gas from the first gas supply source 24 and / or the source gas from the second gas supply source 25 to the nozzle 21. The source gas is N ２ , Ar, H ２ , He, O ２ , CO ２ , N.F. ３ , S.F. ６ , C.F. ４ , CHF ３ The gas supply unit 23 is connected to a control unit 27, and the source gas is supplied from a first gas supply source 24 or a second gas supply source 25 under the control of the control unit 27.

[0029] In one embodiment of the gas cluster ion beam irradiation device, a source gas pressurized to several atmospheres is supplied to the nozzle 21. When the source gas is ejected from the nozzle 21 into the nozzle chamber 20, which is in a vacuum state, at supersonic speed, the source gas is rapidly cooled by adiabatic expansion, and gas clusters are formed by very weak interatomic or intermolecular bonds.

[0030] The gas clusters generated in the nozzle 21 are sorted in the skimmer 22 and introduced into the source chamber 30 .

[0031] The source chamber 30 has an ionization section 31 for ionizing gas clusters and an acceleration section 32 for accelerating the ionized gas clusters. The gas clusters introduced into the source chamber 30 from the skimmer 22 are ionized in the ionization section 31. The gas clusters ionized in the ionization section 31 are accelerated in the acceleration section 32.

[0032] The main chamber 40 has an electrode section 41 that selects gas clusters, a support section 42 that supports the substrate W, and an angle adjustment section 45 that adjusts the angle of the support section 42 .

[0033] The ionized gas clusters accelerated in the acceleration unit 32 are sorted into gas clusters of a predetermined size by an electrode unit 41 provided in the main chamber 40, and are irradiated onto the substrate W supported by a support unit 42. The angle adjustment unit 45 adjusts the angle of the support unit 42, thereby adjusting the incident angle θ of the gas cluster ion beam incident on the substrate W. Here, the incident angle θ (see FIGS. 6A and 6B described later) is the incident angle of the gas cluster ion beam with respect to the surface of the substrate W, and is defined as 90° when the gas cluster ion beam is incident perpendicularly to the surface of the substrate W. The incident angle of the gas cluster ion beam may be perpendicular (θ=90°) or oblique (0°≦θ<90°).

[0034] The etching apparatus (processing chamber 102) has been described as a gas cluster ion beam irradiation apparatus that irradiates the surface of the substrate W with a gas cluster ion beam (GCIB), but is not limited to this. The etching apparatus (processing chamber 102) may be a gas cluster beam irradiation apparatus that irradiates the surface of the substrate W with a gas cluster beam (GCB). The etching apparatus (processing chamber 102) may also be an ion beam irradiation apparatus that irradiates the surface of the substrate W with an ion beam (IB).

[0035] [Substrate Processing Method] Next, an example of a substrate processing method using the substrate processing apparatus 100 shown in Fig. 1 will be described with reference to Fig. 3 and Figs. 4A to 4C. Fig. 3 is a flowchart showing an example of a substrate processing method according to an embodiment. Figs. 4A to 4C are example schematic cross-sectional views of a substrate W in each step of the substrate processing method according to an embodiment.

[0036] In step S101, a substrate W is prepared.

[0037] Here, the substrate W to be prepared has a base film 200 (see FIG. 4A). Here, a carrier C accommodating the substrate W having the base film 200 is attached to one of the load ports 501 to 504. Then, the control device 600 controls the transport mechanism 402 and the like to transport the substrate W from the carrier C to one of the load lock chambers 301 to 303. The control device 600 also controls the transport mechanism 106 and the like to transport the substrate W from one of the load lock chambers 301 to 303 to the processing chamber 101.

[0038] In step S102, a film 210 of the layer material is formed on the substrate W. The control device 600 controls the processing chamber 101 to form the film 210 of the layer material on the substrate W.

[0039] Although it is desirable for the layered material to be in a state in which a layer of atoms bonded in a sheet shape is a single layer or a continuous film with a uniform number of layers, the layered material film 210 actually formed in step S102 is not in this desirable state. FIG. 4A is a schematic diagram showing a cross section of the substrate W after the film formation process in step S102. The layered material film 210 is formed on the base film 200 of the substrate W. The layered material film 210 has a first layer 211 formed directly on the base film 200, a second layer 212 formed on the first layer 211, and a third layer 213 formed on the second layer 212. While the layered material film 210 has been described as having the first layer 211 to the third layer 213 formed, the number of layers in the layered material film 210 is not limited to this and may be up to two layers, or may have four or more layers.

[0040] 4A , the substrate W has a region where the layered material film 210 is not formed on the undercoat film 200, a region where only the first layer 211 is formed on the undercoat film 200, a region where the first layer 211 and the second layer 212 are formed on the undercoat film 200, and a region where the first layer 211 to the third layer 213 are formed on the undercoat film 200. In other words, the layered material film 210 on the undercoat film 200 is a discontinuous film, and the number of layers (film thickness) of the layered material film differs from region to region.

[0041] When the film formation process in the processing chamber 101 is completed, the control device 600 controls the transport mechanism 106 and the like to transport the substrate W from the processing chamber 101 to the processing chamber 102 .

[0042] In step S103, the substrate W is subjected to an etching process.

[0043] Here, the bond energy in the film 210 of the layered material will be described with reference to Fig. 5. Fig. 5 is an example of a schematic diagram showing the bond energy in the film 210 of the layered material.

[0044] The first layer 211 of the layered material film 210 is formed by bonding a metal element M and a chalcogen element X in a sheet-like shape. Similarly, the second layer 212 of the layered material film 210 is also formed by bonding a metal element M and a chalcogen element X in a sheet-like shape. The first layer 211 and the second layer 212 of the layered material film 210 are bonded in the in-plane direction by bonds 250 with strong bond energy, such as ionic bonds or covalent bonds. On the other hand, the layered material film 210 is bonded in the stacking direction between the first layer 211 and the second layer 212 by bonds 255 with weak bond energy, such as van der Waals forces. For example, if the layered material is MoS ２ In this case, the in-plane bond energy (bonds 250 with strong bond energy) is, for example, in the range of 4 eV / atom to 6 eV / atom, while the interlayer bond energy (bonds 255 with weak bond energy) is, for example, in the range of 0.047 eV / atom to 0.060 eV / atom.

[0045] In the processing chamber 102, the substrate W is irradiated with particles to peel off the second layer 212 (including the third layer 213 and subsequent layers) from the first layer 211. For example, the processing chamber 102 is a gas cluster ion beam irradiation device shown in Fig. 3, which irradiates the substrate W with a gas cluster ion beam (GCIB) as particles. Note that the particles irradiated to the substrate W are not limited to this, and may be a gas cluster beam (GCB) or an ion beam (IB).

[0046] Furthermore, the energy of the particles irradiated onto the substrate W is preferably higher than the interlayer bond energy and lower than the in-plane bond energy. Specifically, the energy of the particles irradiated onto the substrate W is preferably 0.05 eV / atom or more and 1 eV / atom or less when the particles are monatomic, and is preferably 0.05 eV / molecular or more and 1 eV / molecular or less when the particles are molecular.

[0047] This prevents the irradiated particles from breaking the bonds within the surface of the first layer 211, while irradiating particles having energy higher than the interlayer bond energy between the first layer 211 and the second layer 212, making it possible to peel the second layer 212 (including the third layer 213 and beyond) from the first layer 211.

[0048] Furthermore, the area of ​​the first layer 211 is larger than the area of ​​the second layer 212. Therefore, the interlayer bond between the base film 200 and the first layer 211 is stronger than the interlayer bond between the first layer 211 and the second layer 212. Therefore, the second layer 212 (including the third layer 213 and subsequent layers) peels off from the first layer 211 before the first layer 211 peels off from the base film 200.

[0049] 6A and 6B are examples of schematic cross-sectional views of the substrate W showing the incident direction of particles.

[0050] As shown in FIG. 6A, the incident direction of particles 810 irradiated onto the substrate W may be perpendicular to the irradiation surface (upper surface) of the substrate W (incident angle θ=90°).

[0051] 6B , the incident direction of the particles 820 irradiated onto the substrate W may be tilted (0°≦θ<90°) with respect to the irradiation surface (top surface) of the substrate W. In this case, the incident direction of the particles 820 has a stacking direction component 821 and an in-plane direction component 822 with respect to the substrate W. By having the in-plane direction component 822 in the incident direction of the particles 820 irradiated onto the substrate W, the second layer 212 (including the third layer 213 and subsequent layers) can be suitably peeled off from the first layer 211. Note that in the diagram shown in FIG. 6B , the layered material is formed parallel to the top surface of the substrate W, but this is not limited to this. Layers of layered materials used in transistors having a three-dimensional structure, for example, are not necessarily formed parallel to the top surface of the substrate W. Even in this case, the incident direction of the irradiated particles 820 may be controlled so that the particles 820 are tilted (0°≦θ<90°) with respect to the main surface (the surface in the stacking direction) of the layered material.

[0052] 4B is a diagram schematically illustrating a cross section of the substrate W after the etching process in step S103. As shown in FIG. 4B, by peeling off the second layer 212 (including the third layer 213 and subsequent layers), the layered material film 210 formed on the base film 200 can be made into a single layer of the first layer 211.

[0053] In other words, the etching process in step S103 selectively etches the second layer 212 and the third layer 213 from the layered material film 210 including the first layer 211, the second layer 212, and the third layer 213. This allows the layered material film 210 formed on the base film 200 to be a single layer of the first layer 211.

[0054] In step S104, the film formation process (S102) and the etching process (S103) are considered as one cycle, and it is determined whether this cycle has been repeated a predetermined number of times. As shown in FIG. 4B , the layered material film 210 after the first etching process (S103) is a discontinuous film, but the discontinuous portions can be compensated for by the second or subsequent film formation process (S102). Furthermore, unnecessary layers formed in the second or subsequent film formation process (S102) can be peeled off by the second or subsequent etching process (S103).

[0055] If the cycle has not been repeated the predetermined number of times (NO in S104), the control device 600 controls the transport mechanism 106 and the like to transport the substrate W from the processing chamber 102 to the processing chamber 101, and controls the processing chamber 101 to perform a film formation process (S102) on the substrate W. Next, the control device 600 controls the transport mechanism 106 and the like to transport the substrate W from the processing chamber 101 to the processing chamber 102, and controls the processing chamber 102 to perform an etching process (S103) on the substrate W. This cycle is repeated thereafter until the predetermined number of times is reached.

[0056] If the process has been repeated a predetermined number of times (YES in S104), the process shown in Fig. 3 is terminated. For example, the control device 600 controls the transport mechanism 106 and the like to transport the substrate W from the processing chamber 102 to one of the load lock chambers 301 to 303. The control device 600 also controls the transport mechanism 402 and the like to store the substrate W from one of the load lock chambers 301 to 303 into one of the carriers C.

[0057] 4C is a schematic diagram showing a cross section of the substrate W after repeating a cycle of the film formation process (S102) and the etching process (S103). As shown in FIG. 4C, the first layer 211 can be formed as a continuous film on the base film 200. Furthermore, by peeling off the second layer 212 (including the third layer 213 and subsequent layers), the layered material film 210 formed on the base film 200 can be a single layer of the first layer 211. For simplicity's sake, the layered material film 210 shown in FIG. 4C is a single layer, but multiple layered materials may be stacked.

[0058] As described above, according to the substrate processing method of one embodiment, the layered material film 210 can be formed as a single layer (first layer 211) on the base film 200. Furthermore, the single layered material film 210 (first layer 211) formed on the base film 200 can be a continuous film.

[0059] The substrate processing method and substrate processing apparatus have been described above, but the present disclosure is not limited to the above-described embodiments, and various modifications and improvements are possible within the scope of the gist of the present disclosure described in the claims.

[0060] This application claims priority based on Japanese Patent Application No. 2023-141486, filed on August 31, 2023, the entire contents of which are incorporated herein by reference.

[0061] REFERENCE SIGNS LIST 100 Substrate processing apparatus 101 Processing chamber (film forming apparatus) 102 Processing chamber (etching apparatus) 105 Vacuum transfer chamber 200 Undercoat film 210 Layered material film 211 First layer 212 Second layer 213 Third layer 600 Control device W Substrate

Claims

1. A substrate processing method comprising the step of irradiating a substrate on which a film of a layered material has been formed with particles to etch the film of the layered material.

2. The substrate processing method according to claim 1, wherein in the step of etching the film of the layered material, the particles are incident at an angle with respect to a main surface of the layered material.

3. The substrate processing method according to claim 1, wherein the energy of the particles irradiated to the substrate is higher than the interlayer bond energy of the film of the layered material and lower than the in-plane bond energy of the film of the layered material.

4. The substrate processing method according to claim 1, wherein the energy of the particles irradiated to the substrate is 1 eV / atom or less if the particles are monatomic, and 1 eV / molecular or less if the particles are molecules.

5. The substrate processing method according to claim 1, wherein the step of etching the film of the layered material comprises irradiating the substrate with any one of a gas cluster ion beam, a gas cluster beam, and an ion beam.

6. The substrate processing method according to claim 1, wherein the layered material is a chalcogenide or graphene.

7. The substrate processing method according to claim 1, wherein the chalcogenide of the layered material contains a metal element and a chalcogen element, the metal element contains any one of molybdenum, tungsten, bismuth, antimony, tin, and germanium, and the chalcogen element contains any one of sulfur, selenium, and tellurium.

8. The substrate processing method according to claim 1, further comprising the steps of forming a film of said layered material on said substrate and etching said film of said layered material, which constitute one cycle, and repeating said cycle.

9. A substrate processing apparatus comprising: a film forming apparatus for forming a film of a layered material on a substrate; an etching apparatus for irradiating particles onto the substrate on which the film of the layered material has been formed, thereby etching the film of the layered material; and a vacuum transfer chamber connected to the film forming apparatus and the etching apparatus, and for transferring the substrate between the film forming apparatus and the etching apparatus.

10. The substrate processing apparatus according to claim 9, wherein the etching apparatus is any one of a gas cluster ion beam irradiation apparatus that irradiates the substrate W with a gas cluster ion beam, a gas cluster beam irradiation apparatus that irradiates the substrate W with a gas cluster beam, and an ion beam irradiation apparatus that irradiates the substrate W with an ion beam.

11. The substrate processing apparatus according to claim 9, wherein the etching apparatus has a support portion for supporting the substrate, and the support portion supports the substrate at an angle with respect to a direction in which the particles are incident.

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