Substrate processing method and substrate processing device

Abstract

A substrate processing method according to one aspect of the present disclosure includes a removal step, a formation step, and an etching step. In the removal step, at least a portion of an initial oxide (C1) on the surface of a molybdenum film (A3) formed on a substrate is removed. In the formation step, a new oxide (C2) is formed on the surface of the molybdenum film (A3) from which at least a portion of the initial oxide (C1) has been removed. In the etching step, the new oxide (C2) and the molybdenum film (A3) are simultaneously etched.

Description

Substrate processing method and substrate processing apparatus

[0001] The disclosed embodiments relate to a substrate processing method and a substrate processing apparatus.

[0002] 2. Description of the Related Art A technique for etching a molybdenum film used as a wiring material for semiconductor devices has been known (see Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2022-104085

[0004] The present disclosure provides a technique that allows uniform etching of molybdenum films.

[0005] A substrate processing method according to one embodiment of the present disclosure includes a removing step, a forming step, and an etching step. The removing step removes at least a portion of an initial oxide on the surface of a molybdenum film formed on a substrate. The forming step forms a new oxide on the surface of the molybdenum film from which at least a portion of the initial oxide has been removed. The etching step simultaneously etches the new oxide and the molybdenum film.

[0006] According to the present disclosure, it is possible to uniformly etch a molybdenum film. Note that the effects described herein are not necessarily limited to those described herein, and any of the effects described in the present disclosure may be achieved.

[0007] FIG. 1 is a schematic block diagram showing the configuration of a substrate processing system according to an embodiment. FIG. 2 is an enlarged cross-sectional view showing an example of the surface state of a wafer before substrate processing. FIG. 3 is an enlarged cross-sectional view showing an example of the surface state of a wafer after a removal process in a reference example. FIG. 4 is an enlarged cross-sectional view showing an example of the surface state of a wafer after an etching process in a reference example. FIG. 5 is an enlarged cross-sectional view showing an example of the surface state of a wafer after a removal process in accordance with an embodiment. FIG. 6 is an enlarged cross-sectional view showing an example of the surface state of a wafer after a formation process in accordance with an embodiment. FIG. 7 is a diagram showing the relationship between the irradiation time of a wafer with ultraviolet light having a wavelength of 172 nm and the film thickness of a new oxide. FIG. 8 is an enlarged cross-sectional view showing an example of the surface state of a wafer after an etching process in accordance with an embodiment. FIG. 9 is a plan view showing the surface state of sample 1. FIG. 10 is a plan view showing the surface state of sample 4. FIG. 11 is a flowchart showing another example of a substrate processing procedure performed by a substrate processing system according to an embodiment.

[0008] Hereinafter, embodiments of a substrate processing method and a substrate processing apparatus disclosed herein will be described in detail with reference to the accompanying drawings. Note that the present disclosure is not limited to the embodiments described below. It should be noted that the drawings are schematic, and the dimensional relationships and ratios of elements may differ from the actual situation. Furthermore, the dimensional relationships and ratios may differ between the drawings.

[0009] Conventionally, techniques for etching molybdenum films used as wiring materials for semiconductor devices have been known. However, the conventional techniques have room for further improvement in terms of uniformly etching the surface of the molybdenum film.

[0010] Therefore, it is desired to realize a technology that can overcome the above-mentioned problems and etch molybdenum films uniformly.

[0011] <Configuration of Substrate Processing System> First, the configuration of a substrate processing system 1 according to an embodiment will be described with reference to Fig. 1. Fig. 1 is a schematic block diagram showing the configuration of the substrate processing system 1 according to an embodiment. The substrate processing system 1 is an example of a substrate processing apparatus.

[0012] As shown in FIG. 1, the substrate processing system 1 according to the embodiment includes a carrier loading / unloading section 2, a substrate transport section 3, a lot loading section 4, a lot transport section 5, a lot processing section 6, a substrate transport section 7, a single wafer processing section 8, and a control section 9.

[0013] The carrier loading / unloading section 2 includes a carrier stage 20 , a carrier transport mechanism 21 , carrier stocks 22 and 23 , and a carrier placement table 24 .

[0014] The carrier stage 20 carries a plurality of carriers C transferred from outside. The carrier C is a container that accommodates a plurality of (e.g., 25) wafers W arranged one above the other in a horizontal position. The carrier transport mechanism 21 transports the carriers C between the carrier stage 20, carrier stocks 22 and 23, and a carrier mounting table 24.

[0015] A plurality of wafers W before processing are transferred from the carrier C placed on the carrier mounting table 24 to the lot mounting section 4 by the substrate transfer section 3. Furthermore, a plurality of processed wafers W are transferred from the lot mounting section 4 to the carrier C placed on the carrier mounting table 24 by the substrate transfer section 3.

[0016] The substrate transfer unit 3 transfers wafers W. The substrate transfer unit 3 forms, for example, a lot. Such a lot is made up of a plurality of wafers W (for example, 50 wafers) W that are simultaneously processed by combining wafers W accommodated in one or more carriers C. The plurality of wafers W that form one lot are arranged at a fixed interval with their plate surfaces facing each other.

[0017] The substrate transfer unit 3 transfers a plurality of wafers W between a carrier C placed on the carrier placement table 24 and the lot placement unit 4. The substrate transfer unit 3 also transfers wafers W one by one between the lot placement unit 4 and the substrate placement table 71 of the substrate transfer unit 7.

[0018] The lot placement unit 4 has a lot transfer table 40 on which a lot transferred by the lot transfer unit 5 between the substrate transfer unit 3 and the lot processing unit 6 is temporarily placed (on standby). The lot transfer table 40 has an entrance side placement table 41 on which a lot formed by the substrate transfer unit 3 is placed before being processed, and an exit side placement table 42 on which a lot processed by the lot processing unit 6 is placed. A plurality of wafers W for one lot are placed in an upright position, lined up front and back, on the entrance side placement table 41 and the exit side placement table 42.

[0019] The lot transport unit 5 has a lot transport mechanism 50, and transports lots between the lot placement unit 4 and the lot processing unit 6 and inside the lot processing unit 6. The lot transport mechanism 50 has rails 51, a moving body 52, and a substrate holder 53.

[0020] The rails 51 are arranged along the X-axis direction across the lot mounting unit 4 and the lot processing unit 6. The movable body 52 is configured to be movable along the rails 51 while holding a plurality of wafers W. The substrate holder 53 is arranged on the movable body 52 and holds a plurality of wafers W lined up in front and behind each other in an upright position.

[0021] The lot processing unit 6 collectively performs liquid processing, rinsing processing, drying processing, etc. on one lot of wafers W. In the lot processing unit 6, a removal processing unit 60, an etching processing unit 61, a cleaning processing unit 62, and a drying processing unit 63 are arranged side by side along rails 51. The removal processing unit 60 is an example of a removal processing unit, and the etching processing unit 61 is an example of an etching processing unit.

[0022] The removal processing device 60 collectively performs removal processing on one lot of a plurality of wafers W. The etching processing device 61 collectively performs etching processing on one lot of a plurality of wafers W.

[0023] The cleaning treatment device 62 performs a cleaning treatment on the substrate holder 53. The drying treatment device 63 performs a drying treatment on one lot of wafers W at once. The numbers of the removal treatment devices 60, etching treatment devices 61, cleaning treatment devices 62, and drying treatment devices 63 are not limited to those shown in FIG.

[0024] The removal processing device 60 includes a processing bath 60a for removal processing, a processing bath 60b for rinsing processing, and substrate lifting mechanisms 60c and 60d.

[0025] The processing tank 60a can accommodate one lot of wafers W arranged in an upright position, and stores a chemical solution for removal processing (hereinafter also referred to as a "removal processing solution"). The removal processing solution is a molybdenum oxide, MoO ２ and MoO ３ The chemical solution is capable of etching the above, such as aqueous ammonia.

[0026] The processing bath 60b stores a processing liquid (deionized water, etc.) for rinsing. The substrate lifting mechanisms 60c and 60d hold a plurality of wafers W that form a lot, aligned in a front-to-back position, in an upright position.

[0027] The removal processing device 60 holds the lot transported by the lot transport unit 5 with the substrate lifting mechanism 60c and immerses it in the removal processing solution in the processing bath 60a to perform the removal processing. The removal processing is performed for, for example, about 60 seconds.

[0028] The lot that has been subjected to the removal process in the processing bath 60a is transferred to the processing bath 60b by the lot transfer unit 5. The removal processing device 60 then holds the transferred lot by the substrate lifting mechanism 60d and immerses it in the rinse liquid in the processing bath 60b, thereby performing a rinse process. The lot that has been rinsed in the processing bath 60b is transferred by the lot transfer unit 5 to the processing bath 64 of the drying processing device 63.

[0029] The drying treatment device 63 includes a treatment tank 64 and a substrate lifting mechanism 65. A treatment gas for drying treatment is supplied to the treatment tank 64. The substrate lifting mechanism 65 holds a plurality of wafers W for one lot in an upright position, lined up front and rear.

[0030] The drying treatment device 63 holds the lot transported by the lot transport unit 5 with a substrate lifting mechanism 65 and performs a drying treatment using a treatment gas for drying treatment supplied into the treatment tank 64. The lot that has been dried in the treatment tank 64 is transported to the lot mounting unit 4 by the lot transport unit 5.

[0031] Then, the substrate transfer unit 3 transfers the plurality of wafers W that have been subjected to the removal process one by one from the lot transferred to the unloading side mounting table 42 of the lot mounting unit 4 to the substrate mounting table 71 of the substrate transfer unit 7 .

[0032] The substrate transport part 7 includes a substrate mounting table 71 and a transport part 72. The single wafer processing part 8, which is located adjacent to the substrate transport part 7, includes a plurality of processing units 81. The processing unit 81 is an example of a forming processing part. The plurality of processing units 81 are arranged side by side on one side of the transport part 72.

[0033] The transfer section 72 includes a substrate transfer device 73 therein. The substrate transfer device 73 includes a wafer holding mechanism that holds the wafer W. The substrate transfer device 73 is capable of moving in the horizontal and vertical directions and rotating about a vertical axis, and transfers the wafer W between the substrate mounting table 71 and the processing unit 81 using the wafer holding mechanism.

[0034] The processing unit 81 performs a formation process on the wafer W transferred by the substrate transfer device 73. The formation process forms an oxide of molybdenum on the surface of the wafer W. In the processing unit 81, for example, the surface of the wafer W is irradiated with ultraviolet light to supply oxygen radicals to the surface of the wafer W, thereby forming an oxide of molybdenum.

[0035] The wafer W subjected to the formation process in the processing unit 81 is transferred to the loading stage 41 of the lot mounting unit 4 by the substrate transfer device 73 and the substrate transfer section 3. Then, the lot transferred from the lot mounting unit 4 by the lot transfer section 5 is transferred to the etching processing device 61.

[0036] The etching treatment device 61 includes a treatment tank 61a for etching treatment, a treatment tank 61b for rinsing treatment, and substrate lifting mechanisms 61c and 61d.

[0037] The processing tank 61a can accommodate one lot of wafers W arranged in an upright position, and stores a chemical solution for etching (hereinafter also referred to as an "etching solution"). The etching solution contains molybdenum and an oxide of molybdenum, MoO ２ This is a chemical solution that can etch both at once.

[0038] The processing bath 61b stores a processing liquid (deionized water, etc.) for rinsing. The substrate lifting mechanisms 61c and 61d hold a plurality of wafers W that form a lot, aligned in front and behind each other in an upright position.

[0039] In the etching treatment device 61, the lot transported by the lot transport unit 5 is held by the substrate lifting mechanism 61c and immersed in the etching solution in the treatment bath 61a to perform the etching treatment. The etching treatment is performed for, for example, several minutes to several tens of minutes.

[0040] The lot etched in the processing bath 61a is transferred to the processing bath 61b by the lot transfer unit 5. The etching processing device 61 then holds the transferred lot by the substrate lifting mechanism 61d and immerses it in the rinse liquid in the processing bath 61b, thereby performing a rinse process.

[0041] The lot that has been rinsed in the processing tank 61b is transferred by the lot transfer unit 5 to the processing tank 64 of the drying treatment device 63. The lot that has been dried in the processing tank 64 is transferred by the lot transfer unit 5 to the lot mounting unit 4. The plurality of wafers W included in the lot that has been transferred to the lot mounting unit 4 are transferred by the substrate transfer unit 3 to a carrier C that is placed on the carrier mounting table 24.

[0042] The control unit 9 controls the operation of each unit (such as the carrier load / unload unit 2, the substrate transport unit 3, the lot placement unit 4, the lot transport unit 5, the lot processing unit 6, the substrate transport unit 7, and the single wafer processing unit 8) of the substrate processing system 1. The control unit 9 controls the operation of each unit of the substrate processing system 1 based on signals from switches, various sensors, etc.

[0043] The control unit 9 includes various circuits and a microcomputer having a central processing unit (CPU), read-only memory (ROM), random access memory (RAM), input / output ports, etc. The control unit 9 controls the operation of the substrate processing system 1 by, for example, reading and executing a program stored in the storage unit 10.

[0044] <Embodiment> Next, details of substrate processing according to an embodiment will be described with reference to Figures 2 to 10. Figure 2 is an enlarged cross-sectional view showing an example of the surface state of a wafer W before substrate processing.

[0045] 2, for example, a base layer A1, an oxide film A2, and a molybdenum film A3 are located near the surface of the wafer W before the substrate processing. The base layer A1 is mainly composed of Si. The oxide film A2 is located on the surface side of the base layer A1 and is made of an oxide of an element constituting the base layer A1 (for example, SiO ｘ ) as its main component.

[0046] The molybdenum film A3 is located on the surface side of the oxide film A2. The molybdenum film A3 is composed of a plurality of columnar molybdenum crystal grains B1 arranged in the surface direction. An initial oxide C1 of molybdenum is formed on the surfaces of the molybdenum crystal grains B1 constituting the molybdenum film A3 so as to cover the molybdenum crystal grains B1.

[0047] In order to uniformly etch the molybdenum film A3, it is considered to remove at least a portion of the initial oxide C1 in advance to homogenize the surface state of the wafer W, as shown in Fig. 3. Fig. 3 is an enlarged cross-sectional view showing an example of the surface state of the wafer W after the removal process in a reference example.

[0048] However, when simply attempting to remove the initial oxide C1, as shown in FIG. 3, in addition to the initial oxide C1, there are cases where the oxide film A2, which is the underlying film of the molybdenum film A3, is also partially removed.

[0049] As a result of extensive research by the present inventors into the cause of this, it was found that the initial oxide C1 formed on the molybdenum film A3 contains MoO ２ and MoO ３ It was revealed that both were included.

[0050] Therefore, it was presumed that if an attempt was made to simply remove the initial oxide C1, etching unevenness would occur in the initial oxide C1 itself, and as a result, even part of the oxide film A2 of the base film would be removed.

[0051] Therefore, when the molybdenum film A3 in the state shown in FIG. 3 is etched, there are cases where the molybdenum crystal grains B1 at the portion where the oxide film A2 has been removed and in the vicinity thereof are entirely peeled off, as shown in FIG.

[0052] Therefore, in the etching process of the molybdenum film A3 according to the embodiment, a removal process is first performed to remove at least a portion of the initial oxide C1 under conditions that can sufficiently remove the initial oxide C1 while minimizing etching of the oxide film A2.

[0053] For example, the removal process of the initial oxide C1 according to the embodiment may be performed using ammonia water (aqueous solution of ammonia). This makes it possible to effectively remove only the initial oxide C1 (see FIG. 2) located on the surfaces of the molybdenum crystal grains B1, as shown in FIG. 5. FIG. 5 is an enlarged cross-sectional view showing an example of the surface state of the wafer W after the removal process according to the embodiment.

[0054] In the embodiment, the concentration of the ammonia water used in the removal treatment may be 1 wt % or less, and the temperature may be 20° C. to 40° C. This makes it possible to more effectively remove only the initial oxide C1 in the removal treatment.

[0055] The chemical used in the removal process according to the embodiment is not limited to ammonia water, but may be any other chemical that can sufficiently remove the initial oxide C1 while providing conditions that minimize etching of the oxide film A2. For example, in the present disclosure, the removal process of the initial oxide C1 may be performed using dilute hydrofluoric acid (DHF).

[0056] In the etching process of the molybdenum film A3 according to the embodiment, after the removal process of the initial oxide C1 described above, a formation process of forming a new oxide C2 on the surface of the molybdenum film A3 may be performed as shown in Fig. 6. Fig. 6 is an enlarged cross-sectional view showing an example of the surface state of the wafer W after the formation process according to the embodiment.

[0057] The new oxide C2 formed in this formation process is, for example, MoO ３ This may be MoO ２ and MoO ３In comparison with the case where the initial oxide C1 containing both of these is formed, the surface of the wafer W can be made uniform.

[0058] Furthermore, in the embodiment, the grain boundaries between adjacent molybdenum crystal grains B1 can be blocked with new oxide C2, so that etching of the oxide film A2, which is the base film, through the grain boundaries can be suppressed in the subsequent etching process.

[0059] For example, the process for forming the new oxide C2 according to the embodiment may be performed using oxygen radicals, which allows the new oxide C2 to be efficiently formed on the surfaces of the molybdenum crystal grains B1.

[0060] Furthermore, the process of forming the new oxide C2 according to the embodiment may be performed by irradiating the wafer W with ultraviolet rays. This allows ozone to be efficiently generated near the surface of the wafer W, and oxygen radicals to be efficiently generated from the ozone. Therefore, according to the embodiment, the new oxide C2 can be more efficiently formed on the surfaces of the molybdenum crystal grains B1.

[0061] In the embodiment, the wavelength of the ultraviolet light irradiated onto the wafer W in the formation process may be 172 nm, which allows new oxides C2 to be formed on the surfaces of the molybdenum crystal grains B1 more efficiently.

[0062] 7 is a diagram showing the relationship between the irradiation time of ultraviolet light with a wavelength of 172 nm on the wafer W and the film thickness of the new oxide C2. As shown in Fig. 7, the film thickness of the new oxide C2 gradually increases as the ultraviolet light irradiation time increases. That is, it can be seen that in this embodiment, the new oxide C2 can be efficiently formed on the surfaces of the molybdenum crystal grains B1 by ultraviolet light irradiation.

[0063] The process of forming the new oxide C2 according to the embodiment may be performed by a means other than irradiating the wafer W with ultraviolet rays. For example, in the present disclosure, the process may be performed by supplying ozone generated by an ozone generator or the like to the wafer W. This also makes it possible to efficiently form the new oxide C2 on the surfaces of the molybdenum crystal grains B1.

[0064] Furthermore, the formation process of the new oxide C2 according to the embodiment may be performed by a means other than oxygen radicals. For example, in the present disclosure, hydrogen peroxide (H ２ O ２ ) or the like. This also allows new oxides C2 to be formed on the surfaces of the molybdenum crystal grains B1.

[0065] In the etching process of the molybdenum film A3 according to the embodiment, following the process of forming the new oxide C2 described above, an etching process may be performed to simultaneously etch the new oxide C2 (see FIG. 6) and the molybdenum crystal grains B1 of the molybdenum film A3, as shown in Fig. 8. Fig. 8 is an enlarged cross-sectional view showing an example of the surface state of the wafer W after the etching process according to the embodiment.

[0066] In this manner, by performing an etching process on the surface of the wafer W that has been made homogenous by the removal process and the formation process, in this embodiment, the molybdenum film A3 can be uniformly etched.

[0067] Table 1 below shows the relationship between the type of chemical used in the removal process, whether ultraviolet (UV) irradiation was performed as the formation process, and the evaluation results of the surface state of the wafer W after the etching process.

[0068]

[0069] As shown in Table 1, it was found that the surface condition of the wafer W after the etching process was improved by using ammonia water in the process of removing the initial oxide C1. It was also found that the surface condition of the wafer W after the etching process was improved by irradiating the wafer W with ultraviolet light as the process of forming a new oxide C2.

[0070] FIG. 9 is a plan view showing the surface state of sample 1, and FIG. 10 is a plan view showing the surface state of sample 4.

[0071] As shown in Fig. 9, in Sample 1, which was rated D, after etching, the phenomenon of stripe-like peeling of molybdenum crystal grains B1 (see Fig. 4) along the flow of the etching solution was frequently observed. This is thought to be because the phenomenon shown in Fig. 4 above occurred in Sample 4.

[0072] On the other hand, as shown in Fig. 10, Sample 4, which was evaluated as Grade A, showed almost no streaky peeling of the molybdenum crystal grains B1 (see Fig. 4) that was observed in Sample 1. The dark colored area at the bottom left in Fig. 10 is due to a phenomenon different from defects such as peeling of the sample.

[0073] The etching process according to the embodiment may be performed using an etching solution containing phosphoric acid, acetic acid, and nitric acid, or an etching solution containing phosphoric acid and an oxidizing agent, thereby enabling the molybdenum film A3 to be uniformly etched.

[0074] The etching process according to the embodiment may be performed using aqueous ammonia, which allows the molybdenum film A3 to be uniformly etched and allows the etching process and the removal process to be performed using the same processing solution.

[0075] In the embodiment, the removal process of the initial oxide C1 may be performed by batch processing in which a plurality of wafers W are processed at once in the removal processing device 60 or the like. This allows the removal process to be performed efficiently on the wafers W.

[0076] In the embodiment, the formation process of the new oxide C2 may be performed by single-wafer processing in which the wafers W are processed one by one in the processing unit 81, etc. This allows the formation process to be performed on the wafers W more reliably.

[0077] In the embodiment, the etching process for simultaneously etching the new oxide C2 and the molybdenum film A3 may be performed as a batch process for processing a plurality of wafers W at once in the etching processing device 61 or the like. This allows the etching process to be performed efficiently on the wafers W.

[0078] In the above embodiment, an example in which the removal process and the etching process are performed in batch processing has been described, but the present disclosure is not limited to such an example, and at least one of the removal process and the etching process may be performed in single-wafer processing, thereby enabling the removal process or the etching process to be performed more reliably on the wafer W.

[0079] In addition, in the above embodiment, an example in which the formation process is performed in a single wafer processing manner has been described, but the present disclosure is not limited to such an example, and the formation process may be performed in a batch processing manner, which allows the formation process to be performed efficiently on the wafers W.

[0080] The substrate processing apparatus (substrate processing system 1) according to the embodiment includes a removal processing unit (removal processing apparatus 60), a formation processing unit (processing unit 81), and an etching processing unit (etching processing apparatus 61). The removal processing unit (removal processing apparatus 60) removes at least a portion of an initial oxide C1 on the surface of a molybdenum film A3 formed on a substrate (wafer W). The formation processing unit (processing unit 81) forms a new oxide C2 on the surface of the molybdenum film A3 from which at least a portion of the initial oxide C1 has been removed. The etching processing unit (etching processing apparatus 61) simultaneously etches the new oxide C2 and the molybdenum film A3. This allows the molybdenum film A3 to be uniformly etched.

[0081] In the substrate processing apparatus (substrate processing system 1) according to the embodiment, the removal processing unit (removal processing device 60) and the etching processing unit (etching processing device 61) perform batch processing for processing a plurality of substrates (wafers W) at once, thereby enabling the removal processing and etching processing of the wafers W to be performed efficiently.

[0082] In the substrate processing apparatus (substrate processing system 1) according to the embodiment, the forming processing section (processing unit 81) performs single-wafer processing, which processes substrates (wafers W) one by one. This allows the forming processing of the wafers W to be more reliably performed.

[0083] <Substrate Processing Procedure> Next, a substrate processing procedure according to the embodiment will be described with reference to Fig. 11. Fig. 11 is a flowchart showing an example of a substrate processing procedure executed by the substrate processing system 1 according to the embodiment.

[0084] In the substrate processing according to the embodiment, first, the control unit 9 loads a plurality of wafers W into the removal processing device 60 at once. Then, the control unit 9 performs removal processing on the plurality of wafers W at once in the processing tank 60a of the removal processing device 60 (step S101).

[0085] Next, the control unit 9 collectively rinses the plurality of wafers W that have been subjected to the removal process in the processing tank 60b of the removal processing device 60, and further collectively dries the plurality of wafers W that have been subjected to the rinse process in the processing tank 64 of the drying processing device 63.

[0086] Next, the control unit 9 transfers the wafers W one by one to the processing unit 81, and the wafers W are subjected to the forming process in the processing unit 81 (step S102).

[0087] Next, the control unit 9 collectively loads the plurality of wafers W that have undergone the formation process into the etching processing unit 61. Then, the control unit 9 collectively etches the plurality of wafers W in the processing tank 61a of the etching processing unit 61 (step S103).

[0088] Next, the control unit 9 rinses the etched wafers W together in the processing tank 61b of the etching processing device 61, and then dries the rinsed wafers W together in the processing tank 64 of the drying processing device 63.

[0089] Finally, the control unit 9 unloads the plurality of wafers W that have been dried from the processing bath 64, thereby completing the series of substrate processing steps.

[0090] The substrate processing method according to the embodiment includes a removal step (step S101), a formation step (step S102), and an etching step (step S103). The removal step (step S101) removes at least a portion of an initial oxide C1 on the surface of a molybdenum film A3 formed on a substrate (wafer W). The formation step (step S102) forms a new oxide C2 on the surface of the molybdenum film A3 from which at least a portion of the initial oxide C1 has been removed. The etching step (step S103) simultaneously etches the new oxide C2 and the molybdenum film A3. This allows the molybdenum film A3 to be uniformly etched.

[0091] In the substrate processing method according to the embodiment, the removal step (step S101) is performed using ammonia water, which makes it possible to effectively remove only the initial oxides C1 located on the surfaces of the molybdenum crystal grains B1.

[0092] In the substrate processing method according to the embodiment, the concentration of the ammonia water is 1 wt % or less, and the temperature is 20° C. to 40° C. This makes it possible to more effectively remove only the initial oxides C1 in the removal process.

[0093] In the substrate processing method according to the embodiment, the forming step (step S102) is performed using oxygen radicals, which allows new oxides C2 to be efficiently formed on the surfaces of the molybdenum crystal grains B1.

[0094] In the substrate processing method according to the embodiment, the forming step (step S102) is performed by irradiating the substrate (wafer W) with ultraviolet light, which allows new oxides C2 to be formed more efficiently on the surfaces of the molybdenum crystal grains B1.

[0095] In the substrate processing method according to the embodiment, the wavelength of the ultraviolet light is 172 nm, which allows new oxides C2 to be formed on the surfaces of the molybdenum crystal grains B1 more efficiently.

[0096] In the substrate processing method according to the embodiment, the initial oxide C1 is MoO ２ and MoO ３This allows the molybdenum film A3 to be etched uniformly.

[0097] In the substrate processing method according to the embodiment, the new oxide C2 is MoO ３ This allows the molybdenum film A3 to be etched uniformly.

[0098] In the substrate processing method according to the embodiment, the etching process (step S103) is performed using an etching solution containing phosphoric acid, acetic acid, and nitric acid, or an etching solution containing phosphoric acid and an oxidizing agent, thereby enabling the molybdenum film A3 to be uniformly etched.

[0099] In the substrate processing method according to the embodiment, the etching process (step S103) is performed using aqueous ammonia, which allows the molybdenum film A3 to be uniformly etched and allows the etching process and the removal process to be performed using the same processing solution.

[0100] Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments, and various modifications are possible without departing from the spirit of the present disclosure.

[0101] The disclosed embodiments should be considered in all respects as illustrative and not restrictive. Indeed, the above-described embodiments may be embodied in various forms. Furthermore, the above-described embodiments may be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended claims.

[0102] REFERENCE SIGNS LIST 1 Substrate processing system (an example of a substrate processing apparatus) 60 Removal processing apparatus (an example of a removal processing section) 61 Etching processing apparatus (an example of an etching processing section) 81 Processing unit (an example of a formation processing section) W Wafer (an example of a substrate) A3 Molybdenum film C1 Initial oxide C2 New oxide

Claims

1. A substrate processing method comprising: a removal step of removing at least a portion of an initial oxide on the surface of a molybdenum film formed on a substrate; a formation step of forming a new oxide on the surface of the molybdenum film from which at least a portion of the initial oxide has been removed; and an etching step of simultaneously etching the new oxide and the molybdenum film.

2. The substrate processing method according to claim 1, wherein the removing step is performed using ammonia water.

3. The substrate processing method according to claim 2, wherein the concentration of the ammonia water is 1 wt % or less and the temperature is 20°C to 40°C.

4. The substrate processing method according to any one of claims 1 to 3, wherein the forming step is carried out by oxygen radicals.

5. The substrate processing method according to claim 4, wherein the forming step is carried out by irradiating the substrate with ultraviolet light.

6. The substrate processing method according to claim 5, wherein the ultraviolet light has a wavelength of 172 nm.

7. The initial oxide is MoO ２ and MoO ３ The substrate processing method according to any one of claims 1 to 3, wherein the mixture is a mixture of 8. The new oxide is MoO ３ The substrate processing method according to any one of claims 1 to 3, wherein 9. The substrate processing method according to any one of claims 1 to 3, wherein the etching step is carried out using an etching solution containing phosphoric acid, acetic acid and nitric acid, or an etching solution containing phosphoric acid and an oxidizing agent.

10. The substrate processing method according to any one of claims 1 to 3, wherein the etching step is performed using ammonia water.

11. A substrate processing apparatus comprising: a removal processing unit that removes at least a portion of an initial oxide on the surface of a molybdenum film formed on a substrate; a formation processing unit that forms a new oxide on the surface of the molybdenum film from which at least a portion of the initial oxide has been removed; and an etching processing unit that simultaneously etches the new oxide and the molybdenum film.

12. The substrate processing apparatus according to claim 11, wherein the removal processing section and the etching processing section perform batch processing for processing a plurality of the substrates at once.

13. The substrate processing apparatus according to claim 11 or 12, wherein the forming processing section performs single-wafer processing, processing the substrates one by one.

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