Cleaning method and film formation apparatus

Abstract

To provide a technique capable of reducing a difference in film properties between a first film formation process performed after cleaning and second and subsequent film formation processes performed after the cleaning.SOLUTION: Provided is a cleaning method for a film formation apparatus configured to form a molybdenum film over a plurality of substrates housed in a processing container, the cleaning method including (a) supplying a cleaning gas into the processing container, thereby removing the molybdenum film deposited in an interior of the processing container; (b) after (a), coating the interior of the processing container with a molybdenum nitride film; and (c) after (b), coating the interior of the processing container with the molybdenum film.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a cleaning method and a film forming apparatus. [Background technology]

[0002] A technique for forming a molybdenum film on an insulating film is known (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-186307 Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides a technique that can reduce the difference in film characteristics between the first film formation process performed after cleaning and the second and subsequent film formation processes. [Means for solving the problem]

[0005] A cleaning method according to one aspect of the present disclosure is a cleaning method for a film formation apparatus that accommodates multiple substrates in a processing vessel and forms a molybdenum film thereon, the method comprising the steps of: (a) supplying a cleaning gas into the processing vessel to remove a molybdenum film deposited in the processing vessel; (b) coating the inside of the processing vessel with a molybdenum nitride film after step (a); and (c) coating the inside of the processing vessel with a molybdenum film after step (b). [Effects of the Invention]

[0006] According to the present disclosure, it is possible to reduce the difference in film characteristics between the first film formation process performed after cleaning and the second and subsequent film formation processes. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a vertical cross-sectional view showing a film forming apparatus according to an embodiment. [Figure 2] 1 is a horizontal cross-sectional view showing a film forming apparatus according to an embodiment. [Figure 3] 3 is a flowchart illustrating a cleaning method according to an embodiment. [Figure 4] 10 is a flowchart showing an example of a first coating step. [Figure 5] 10 is a flowchart showing an example of a second coating step. [Figure 6] FIG. 10 is a diagram showing the relationship between the first number of times and the thickness of a molybdenum nitride film. [Figure 7] FIG. 10 is a diagram showing the relationship between the second number of times and the thickness of the molybdenum film. [Figure 8] FIG. 10 is a diagram showing the measurement results of the thickness of a molybdenum film in an example. [Figure 9] FIG. 10 is a diagram showing the measurement results of the thickness of a molybdenum film in a comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, non-limiting exemplary embodiments of the present disclosure will be described with reference to the accompanying drawings. In all the accompanying drawings, the same or corresponding reference numerals are used to designate the same or corresponding members or components, and redundant descriptions will be omitted.

[0009] [Film forming equipment] A film forming apparatus 1 according to an embodiment will be described with reference to Figures 1 and 2. Figure 1 is a vertical cross-sectional view showing the film forming apparatus 1 according to an embodiment. Figure 2 is a horizontal cross-sectional view showing the film forming apparatus 1 according to an embodiment.

[0010] The film forming apparatus 1 is a batch type apparatus that processes a plurality of substrates W at once. The substrates W are, for example, semiconductor wafers. The film forming apparatus 1 includes a processing chamber 10, a gas supply unit 30, an exhaust unit 40, a heating unit 50, and a control unit 90.

[0011] The processing vessel 10 can have its interior depressurized. The processing vessel 10 accommodates a substrate W. The processing vessel 10 has an inner tube 11 and an outer tube 12. The inner tube 11 has a cylindrical shape with a ceiling and an open lower end. The outer tube 12 has a cylindrical shape with a ceiling and an open lower end that covers the outside of the inner tube 11. The inner tube 11 and the outer tube 12 are made of a heat-resistant material such as quartz. The inner tube 11 and the outer tube 12 have a double-tube structure arranged coaxially.

[0012] A storage section 13 for storing a gas supply pipe is formed along the longitudinal direction (vertical direction) on the side wall of the inner pipe 11. For example, a part of the side wall of the inner pipe 11 is protruded outward to form a convex section 14, and the inside of the convex section 14 is formed as the storage section 13.

[0013] A rectangular opening 15 is formed along the longitudinal direction in the side wall of the inner tube 11. The opening 15 faces the storage portion 13.

[0014] The opening 15 is a gas exhaust port formed so as to be able to exhaust gas from the inner tube 11. The length of the opening 15 is the same as the length of the boat 16, or is formed so as to extend in the vertical direction longer than the length of the boat 16.

[0015] The lower end of the processing vessel 10 is supported by a cylindrical manifold 17. The manifold 17 is made of, for example, stainless steel. A flange 18 is formed at the upper end of the manifold 17. The flange 18 supports the lower end of the outer tube 12. A seal member 19, such as an O-ring, is provided between the flange 18 and the lower end of the outer tube 12. This keeps the inside of the outer tube 12 airtight.

[0016] An annular support member 20 is provided on the inner wall of the upper portion of the manifold 17. The support member 20 supports the lower end of the inner tube 11. A lid member 21 is airtightly attached to the opening at the lower end of the manifold 17 via a sealing member 22 such as an O-ring. This airtightly closes the opening at the lower end of the processing vessel 10, i.e., the opening of the manifold 17. The lid member 21 is made of, for example, stainless steel.

[0017] A rotating shaft 24 is provided in the center of the lid 21, penetrating through the lid 21 via a magnetic fluid seal 23. The lower part of the rotating shaft 24 is rotatably supported by an arm 25A of an elevation mechanism 25 made up of a boat elevator.

[0018] A rotating plate 26 is provided at the upper end of the rotating shaft 24. A boat 16 holding substrates W is placed on the rotating plate 26 via a quartz heat retention stand 27. The boat 16 rotates by rotating the rotating shaft 24. The boat 16 moves up and down integrally with the lid 21 by raising and lowering the lifting mechanism 25. This allows the boat 16 to be inserted into and removed from the processing vessel 10. The boat 16 can be accommodated within the processing vessel 10. The boat 16 holds multiple (e.g., 50 to 150) substrates W in a shelf-like manner. The boat 16 holds the multiple substrates W approximately horizontally with spacing between them in the vertical direction.

[0019] The gas supply unit 30 is configured to be able to introduce various process gases into the inner tube 11. The gas supply unit 30 includes a MoO2Cl2 supply unit 31, an ammonia supply unit 32, a hydrogen supply unit 33, and a fluorine supply unit .

[0020] The MoO2Cl2 supply unit 31 includes a gas supply pipe 31a inside the processing vessel 10 and a supply flow path 31b outside the processing vessel 10. A MoO2Cl2 source 31c, a mass flow controller 31d, and a valve 31e are installed in the supply flow path 31b, in this order from upstream to downstream in the gas flow direction. The supply timing of MoO2Cl2 gas from the MoO2Cl2 source 31c is controlled by the valve 31e, and the flow rate is adjusted to a predetermined value by the mass flow controller 31d. The MoO2Cl2 gas flows from the supply flow path 31b into the gas supply pipe 31a and is then discharged from the gas supply pipe 31a into the processing vessel 10. The MoO2Cl2 gas is an example of a molybdenum-containing gas.

[0021] The ammonia supply unit 32 includes a gas supply pipe 32a inside the processing vessel 10 and a supply flow path 32b outside the processing vessel 10. An ammonia source 32c, a mass flow controller 32d, and a valve 32e are installed in the supply flow path 32b, in this order from upstream to downstream in the gas flow direction. Thus, the supply timing of ammonia (NH) gas from the ammonia source 32c is controlled by the valve 32e, and the flow rate is adjusted to a predetermined value by the mass flow controller 32d. The ammonia gas flows from the supply flow path 32b into the gas supply pipe 32a and is discharged from the gas supply pipe 32a into the processing vessel 10. The ammonia gas is an example of a nitriding gas.

[0022] The hydrogen supply unit 33 includes a gas supply pipe 33a inside the processing vessel 10 and a supply flow path 33b outside the processing vessel 10. A hydrogen source 33c, a mass flow controller 33d, and a valve 33e are installed in the supply flow path 33b, in this order from upstream to downstream in the gas flow direction. Thus, the supply timing of hydrogen (H2) gas from the hydrogen source 33c is controlled by the valve 33e, and the mass flow controller 33d adjusts the flow rate to a predetermined value. The hydrogen gas flows from the supply flow path 33b into the gas supply pipe 33a and is discharged from the gas supply pipe 33a into the processing vessel 10. The hydrogen gas is an example of a reducing gas.

[0023] The fluorine supply unit 34 includes a gas supply pipe 34a inside the processing vessel 10 and a supply flow path 34b outside the processing vessel 10. In the supply flow path 34b, a fluorine source 34c, a mass flow controller 34d, and a valve 34e are installed in this order from upstream to downstream in the gas flow direction. Thus, the supply timing of fluorine (F2) gas from the fluorine source 34c is controlled by the valve 34e, and the flow rate is adjusted to a predetermined value by the mass flow controller 34d. The fluorine gas flows from the supply flow path 34b into the gas supply pipe 34a and is discharged from the gas supply pipe 34a into the processing vessel 10. The fluorine gas is an example of a cleaning gas.

[0024] The gas supply pipes 31a, 32a, 33a, and 34a are fixed to the manifold 17. The gas supply pipes 31a, 32a, 33a, and 34a are made of, for example, quartz. The gas supply pipes 31a, 32a, 33a, and 34a extend linearly in the vertical direction near the inner pipe 11, and then bend in an L-shape within the manifold 17 and extend horizontally, thereby penetrating the manifold 17. The gas supply pipes 31a, 32a, 33a, and 34a are arranged side by side along the circumferential direction of the inner pipe 11 and are formed at the same height.

[0025] A plurality of discharge ports 31f, 32f, 33f, and 34f are provided in the gas supply pipes 31a, 32a, 33a, and 34a at positions within the inner pipe 11. The discharge ports 31f, 32f, 33f, and 34f are formed at predetermined intervals along the extension direction of the gas supply pipes 31a, 32a, 33a, and 34a. Each discharge port 31f, 32f, 33f, and 34f discharges gas horizontally toward the substrate W from the radially outer side of the substrate W. Each discharge port 31f, 32f, 33f, and 34f discharges gas parallel to the main surface of the substrate W. The intervals between the discharge ports are set to, for example, the same as the intervals between the substrates W held in the boat 16. The height position of each discharge port is set to, for example, the midpoint between vertically adjacent substrates W. In this case, each discharge port can efficiently supply gas to the opposing surfaces of adjacent substrates W.

[0026] The gas supply unit 30 may mix multiple types of gases and discharge the mixed gas from a single gas supply pipe. The gas supply pipes 31a, 32a, 33a, and 34a may have different shapes and arrangements. The gas supply unit 30 may further include a gas supply pipe that supplies another gas, for example, an inert gas such as argon gas.

[0027] The exhaust unit 40 exhausts gas that is discharged from the inner tube 11 through the opening 15 and then discharged from a gas outlet 41 via a space P1 between the inner tube 11 and the outer tube 12. The gas outlet 41 is formed on the side wall of the upper part of the manifold 17, above the support unit 20. An exhaust flow path 42 is connected to the gas outlet 41. A pressure adjustment valve 43 and a vacuum pump 44 are sequentially disposed in the exhaust flow path 42, so that the inside of the processing chamber 10 can be exhausted.

[0028] The heating unit 50 is provided around the outer tube 12. The heating unit 50 is provided, for example, on the base plate 28. The heating unit 50 has a cylindrical shape so as to cover the outer tube 12. The heating unit 50 includes, for example, a heater, and heats each substrate W in the processing chamber 10.

[0029] The control unit 90 is an electronic circuit such as a CPU (Central Processing Unit), FPGA (Field Programmable Gate Array), ASIC (Application Specific Integrated Circuit), etc. The control unit 90 executes various control operations described in this specification by executing instruction codes stored in a memory or by being a circuit designed for a specific application.

[0030] [Cleaning method] A cleaning method according to an embodiment will be described with reference to FIGS. 3 to 7. The following description will be given taking a cleaning method executed in the film formation apparatus 1 as an example. The cleaning method according to the embodiment is automatically executed under the control of the control unit 90. The cleaning method according to the embodiment is performed when no substrates W are present in the processing chamber 10. The cleaning method according to the embodiment is performed, for example, when a process (hereinafter also referred to as a "film formation process") for forming a molybdenum (Mo) film on a plurality of substrates W is repeatedly performed in the processing chamber 10 of the film formation apparatus 1 and the cumulative thickness of the molybdenum film deposited in the processing chamber 10 exceeds a threshold thickness. When the cumulative thickness of the molybdenum film deposited in the processing chamber 10 exceeds the threshold thickness, particles are likely to increase.

[0031] 3 is a flowchart showing the cleaning method according to the embodiment. As shown in FIG. 3, the cleaning method according to the embodiment includes a cleaning step S1, a first coating step S2, and a second coating step S3.

[0032] (Cleaning process S1) In the cleaning step S1, the control unit 90 controls each part of the film forming apparatus 1 so as to supply fluorine gas into the processing chamber 10 and remove the molybdenum film deposited inside the processing chamber 10.

[0033] First, the heating unit 50 adjusts the temperature inside the processing vessel 10 to a first temperature. The first temperature is equal to or higher than 300°C and equal to or lower than 350°C. Next, the gas supply unit 30 supplies fluorine gas into the processing vessel 10, and the exhaust unit 40 maintains the inside of the processing vessel 10 at a predetermined pressure. As a result, the fluorine gas reacts with the molybdenum film inside the processing vessel 10, and the molybdenum film deposited inside the processing vessel 10 is removed. Once the molybdenum film deposited inside the processing vessel 10 is removed, the gas supply unit 30 stops supplying the fluorine gas into the processing vessel 10. The gas supply unit 30 may supply a dilution gas together with the fluorine gas. The dilution gas is, for example, an inert gas such as nitrogen (N2) gas or argon (Ar) gas.

[0034] (First coating step S2) The first coating step S2 is performed after the cleaning step S1. In the first coating step S2, the control unit 90 controls each component of the film forming apparatus 1 to coat the inside of the processing chamber 10 with a molybdenum nitride (MoN) film. The molybdenum nitride film can be formed, for example, by atomic layer deposition (ALD) in which MoOCl gas and ammonia gas are alternately supplied into the processing chamber 10. The molybdenum nitride film can also be formed by chemical vapor deposition (CVD) in which MoOCl gas and ammonia gas are simultaneously supplied. The thickness of the molybdenum nitride film is, for example, 1.5 nm or more and 3 nm or less. In this case, a molybdenum film is likely to be formed on the molybdenum nitride film in the second coating step S3.

[0035] FIG. 4 is a flowchart showing an example of the first coating step S2. As shown in FIG. 4, the first coating step S2 includes steps S21 to S25. In steps S21 to S25, the heating unit 50 adjusts the temperature inside the processing vessel 10 to a second temperature. The second temperature is, for example, the same as the first temperature. In this case, the temperature inside the processing vessel 10 does not need to be changed when transitioning from the cleaning step S1 to the first coating step S2, thereby improving productivity. The second temperature is, for example, 250°C or higher and 600°C or lower.

[0036] In step S21, the gas supply unit 30 supplies the MoO2Cl2 gas into the processing vessel 10. As a result, the MoO2Cl2 gas is adsorbed into the processing vessel 10.

[0037] In step S22, the gas supply unit 30 supplies a purge gas into the processing vessel 10, and the exhaust unit 40 exhausts the gas inside the processing vessel 10. This exhausts the MoO2Cl2 gas remaining in the processing vessel 10. The supply of the purge gas and the exhaust of the gas may be performed simultaneously or asynchronously. The purge gas is, for example, an inert gas such as argon gas or nitrogen gas.

[0038] In step S23, the gas supply unit 30 supplies ammonia gas into the processing vessel 10. As a result, the MoO2Cl2 gas adsorbed in the processing vessel 10 is nitrided, and a molybdenum nitride film is formed.

[0039] In step S24, the gas supply unit 30 supplies a purge gas into the processing vessel 10, and the exhaust unit 40 exhausts the gas inside the processing vessel 10. This exhausts the ammonia gas remaining inside the processing vessel 10. The supply of the purge gas and the exhaust of the gas may be performed simultaneously or asynchronously.

[0040] In step S25, the control unit 90 determines whether steps S21 to S24 have been performed in this order a first number of times. If the number of times has not reached the first number of times (NO in step S25), the control unit 90 performs steps S21 to S24 again. If the number of times has reached the first number of times (YES in step S25), the control unit 90 ends the process. In this way, steps S21 to S24 are repeated in this order until the number of times reaches the first number of times, thereby adjusting the thickness of the molybdenum nitride film coated inside the processing vessel 10. The first number of times may be one time, or may be two or more times. The first number of times is, for example, 25 times.

[0041] (Second coating step S3) The second coating step S3 is performed after the first coating step S2. In the second coating step S3, the control unit 90 controls each component of the film forming apparatus 1 to coat the interior of the processing chamber 10 with a molybdenum film. The molybdenum film can be formed, for example, by an ALD method in which MoO2Cl2 gas and hydrogen gas are alternately supplied into the processing chamber 10. The molybdenum film can also be formed by a CVD method in which MoO2Cl2 gas and hydrogen gas are simultaneously supplied. The thickness of the molybdenum film is, for example, 100 nm or more and 120 nm or less. In this case, the time required for the second coating step S3 can be shortened while minimizing the variation in thickness of the molybdenum film among multiple substrates W during the film formation process performed after cleaning.

[0042] FIG. 5 is a flowchart showing an example of the second coating step S3. As shown in FIG. 5, the second coating step S3 includes steps S31 to S35. In steps S31 to S35, the heating unit 50 adjusts the temperature inside the processing vessel 10 to a third temperature. The third temperature is, for example, a temperature higher than the second temperature. In this case, it is easy to uniformly coat the entire inside of the processing vessel 10 with a molybdenum film. The third temperature is, for example, 450°C or higher and 600°C or lower. The third temperature may be the same as the second temperature. In this case, the temperature inside the processing vessel 10 does not need to be changed when transitioning from the first coating step S2 to the second coating step S3, thereby improving productivity.

[0043] In step S31, the gas supply unit 30 supplies the MoO2Cl2 gas into the processing vessel 10. As a result, the MoO2Cl2 gas is adsorbed into the processing vessel 10.

[0044] In step S32, the gas supply unit 30 supplies a purge gas into the processing vessel 10, and the exhaust unit 40 exhausts the gas inside the processing vessel 10. This exhausts the MoO2Cl2 gas remaining in the processing vessel 10. The supply of the purge gas and the exhaust of the gas may be performed simultaneously or asynchronously.

[0045] In step S33, the gas supply unit 30 supplies hydrogen gas into the processing vessel 10. As a result, the MoO2Cl2 gas adsorbed in the processing vessel 10 is reduced, and a molybdenum film is formed.

[0046] In step S34, the gas supply unit 30 supplies a purge gas into the processing vessel 10, and the exhaust unit 40 exhausts the gas inside the processing vessel 10. This exhausts the hydrogen gas remaining inside the processing vessel 10. The supply of the purge gas and the exhaust of the gas may be performed simultaneously or asynchronously.

[0047] In step S35, the control unit 90 determines whether steps S31 to S34 have been performed in this order a second number of times. If the number of times has not reached the second number of times (NO in step S35), the control unit 90 performs steps S31 to S34 again. If the number of times has reached the second number of times (YES in step S35), the control unit 90 ends the process. In this way, steps S31 to S34 are repeated in this order until the number of times reaches the second number of times, thereby adjusting the thickness of the molybdenum film coated inside the processing vessel 10. The second number of times may be one time, or may be two or more times. The second number of times is, for example, 2000 times.

[0048] 6 is a diagram showing the relationship between the first number of times and the thickness of the molybdenum nitride film, in which the horizontal axis represents the first number of times and the vertical axis represents the thickness of the molybdenum nitride film formed on quartz.

[0049] 6, when forming a molybdenum nitride film on quartz, the thickness of the molybdenum nitride film increases in proportion to the first number of times immediately after starting the formation of the molybdenum nitride film. In other words, the incubation time when forming the molybdenum nitride film on quartz is very short. Therefore, the molybdenum nitride film is easily formed even in areas of the processing vessel 10 where it is difficult to form a molybdenum film.

[0050] Portions on which a molybdenum film is difficult to form include, for example, the surface of the rotating plate 26, the surface of the heat-retaining table 27, and the inner wall surface of the outer tube 12. The surfaces of the rotating plate 26 and the heat-retaining table 27 are outside the temperature control range during the second coating step S3 and are lower than the controlled temperature. In contrast, the surface of the boat 16 is within the temperature control range during the second coating step S3. Therefore, the surfaces of the rotating plate 26 and the heat-retaining table 27 are less likely to be coated with a molybdenum film than the surface of the boat 16. The boat 16 is an example of a substrate holder, and the surface of the boat 16 is an example of a first surface. The rotating plate 26 and the heat-retaining table 27 are examples of a support, and the surfaces of the rotating plate 26 and the heat-retaining table 27 are examples of a second surface. The MoO2Cl2 gas discharged from the outlet 31f of the gas supply pipe 31a is difficult to reach the inner wall surface of the outer tube 12. Therefore, the inner wall surface of the outer tube 12 is less likely to be coated with a molybdenum film.

[0051] Fig. 7 shows the relationship between the second number of times and the thickness of the molybdenum film. In Fig. 7, the horizontal axis represents the second number of times, and the vertical axis represents the thickness of the molybdenum film formed on the quartz. In Fig. 7, the solid line represents the thickness of the molybdenum film when a molybdenum nitride film is present on the quartz, and the dashed line represents the thickness of the molybdenum film when no molybdenum nitride film is present on the quartz.

[0052] As shown in FIG. 7 , when a molybdenum film is formed on quartz, if a molybdenum nitride film is present on the quartz, the thickness of the molybdenum film increases immediately after the start of molybdenum film formation in proportion to the second number of times. In contrast, if a molybdenum nitride film is not present on the quartz, the thickness of the molybdenum film increases in proportion to the second number of times after a predetermined number of times have elapsed since the start of molybdenum film formation. In other words, if a molybdenum nitride film is present on the quartz, the incubation time required for forming a molybdenum film on quartz is shorter than if a molybdenum nitride film is not present on the quartz. Therefore, by forming a molybdenum film with a molybdenum nitride film on the quartz, it is possible to easily form a molybdenum film on areas of the processing vessel 10 where it is difficult to form a molybdenum film. In other words, the entire interior of the processing vessel 10 can be coated with a molybdenum film. This allows the coating state of the molybdenum film inside the processing vessel 10 during the first film formation process performed after cleaning to be closer to the coating state of the molybdenum film inside the processing vessel 10 during the second film formation process performed after cleaning, thereby reducing the difference in film characteristics between the first film formation process performed after cleaning and the second and subsequent film formation processes.

[0053] On the other hand, if there are areas in the process vessel 10 that are not coated with a molybdenum film, the MoO2Cl2 gas is less likely to adsorb to those areas during the first film formation process performed after cleaning, resulting in a reduced consumption of MoO2Cl2 gas at those areas. As a result, the concentration of MoO2Cl2 gas near the boat 16 increases by the amount of MoO2Cl2 gas not consumed at those areas, and the thickness of the molybdenum film formed on the multiple substrates W held in the boat 16 increases. During the first film formation process performed after cleaning, a molybdenum film begins to coat those areas over time. As a result, during the second film formation process performed after cleaning, the concentration of MoO2Cl2 gas near the boat 16 decreases compared to the first film formation process. Thus, the state inside the process vessel 10 during the first film formation process performed after cleaning differs from the state inside the process vessel 10 during the second film formation process performed after cleaning. As a result, differences in film characteristics are likely to occur between the first and second film formation processes performed after cleaning.

[0054] [Example] In the example, first, the cleaning step S1, the first coating step S2, and the second coating step S3 of the cleaning method according to the embodiment were performed in this order in the film formation apparatus 1. Next, the film formation process was performed three times in the processing container 10. Next, the thicknesses of the molybdenum films formed on the substrates W in the first, second, and third film formation processes were measured.

[0055] In the comparative example, first, the cleaning step S1 and the second coating step S3 of the cleaning method according to the embodiment were performed in this order in the film formation apparatus 1. In the comparative example, the first coating step S2 was not performed. Next, under the same conditions as in the example, the film formation process was performed three times in the processing container 10. Next, the thicknesses of the molybdenum films formed on the substrate W in the first, second, and third film formation processes were measured.

[0056] Fig. 8 shows the results of measuring the thickness of a molybdenum film in an example. Fig. 9 shows the results of measuring the thickness of a molybdenum film in a comparative example. In Figs. 8 and 9, the horizontal axis indicates the position of the substrate W, and indicates either the upper, central, or lower part of the boat 16. In Figs. 8 and 9, the vertical axis indicates the thicknesses of the molybdenum films formed in the first, second, and third film formation processes, expressed as relative values ​​when the thickness of the molybdenum film formed in the second film formation process is set to 1. In Figs. 8 and 9, squares, circles, and triangles indicate the thicknesses of the molybdenum films formed in the first, second, and third film formation processes, respectively.

[0057] As shown in Figure 8, in the example, the thickness of the molybdenum film formed in the first film formation process is approximately the same as the thickness of the molybdenum film formed in the second and third film formation processes. In contrast, as shown in Figure 9, in the comparative example, the thickness of the molybdenum film formed in the first film formation process is thicker than the thickness of the molybdenum film formed in the second and third film formation processes. From the above, it was shown that by performing the cleaning step S1, the first coating step S2, and the second coating step S3 in this order, it is possible to reduce the difference in film characteristics between the first film formation process performed after cleaning and the second and subsequent film formation processes.

[0058] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive, and the above-described embodiments may be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended claims.

[0059] In the above embodiment, the cleaning gas is fluorine gas, but the present disclosure is not limited to this. For example, the cleaning gas may be chlorine (Cl2) gas.

[0060] In the above embodiment, the molybdenum-containing gas is MoO2Cl2 gas, but the present disclosure is not limited thereto. For example, the molybdenum-containing gas may be MoCl5 gas.

[0061] In the above embodiment, the nitriding gas is ammonia gas, but the present disclosure is not limited to this. For example, the nitriding gas may be N2 gas. [Explanation of symbols]

[0062] 1 Film deposition equipment 10 Processing container 30 Gas supply unit 90 Control Unit W substrate

Claims

1. 1. A cleaning method for a film formation apparatus that forms a molybdenum film by accommodating a plurality of substrates in a processing vessel, comprising: (a) supplying a cleaning gas into the processing vessel to remove a molybdenum film deposited in the processing vessel; (b) after the step (a), coating the inside of the processing vessel with a molybdenum nitride film; (c) after the step (b), coating the inside of the processing vessel with a molybdenum film; A cleaning method comprising:

2. the step (a) is performed after the process of forming the molybdenum film on the plurality of substrates in the process container has been performed. The cleaning method according to claim 1 .

3. the step (b) includes alternately supplying a molybdenum-containing gas and a nitriding gas into the processing vessel; The cleaning method according to claim 1 .

4. the step (c) includes alternately supplying a molybdenum-containing gas and a reducing gas into the treatment vessel; The cleaning method according to claim 1 .

5. The step (c) is carried out at a temperature higher than that of the step (b). The cleaning method according to claim 1 .

6. The step (c) is carried out at the same temperature as the step (b). The cleaning method according to claim 1 .

7. The steps (a), (b), and (c) are performed in a state where no substrate is present in the processing chamber. The cleaning method according to claim 1 .

8. The cleaning gas is fluorine gas. The cleaning method according to any one of claims 1 to 7.

9. The processing vessel includes a first surface and a second surface maintained at a temperature lower than that of the first surface, the step (b) includes coating the first surface and the second surface with the molybdenum nitride film; The cleaning method according to any one of claims 1 to 7.

10. the first surface is a surface of a substrate holder that holds the plurality of substrates; the second surface is a surface of a support that supports the substrate holder; The cleaning method according to claim 9.

11. A film formation apparatus that forms a molybdenum film by accommodating a plurality of substrates in a processing chamber, the processing vessel; a gas supply unit that supplies a processing gas into the processing vessel; A control unit; Equipped with The control unit (a) supplying a cleaning gas into the processing vessel to remove a molybdenum film deposited in the processing vessel; (b) after the step (a), coating the inside of the processing vessel with a molybdenum nitride film; (c) after the step (b), coating the inside of the processing vessel with a molybdenum film; configured to perform Film deposition equipment.

Images