Substrate processing method and substrate processing apparatus

Abstract

To suppress metal contamination of a substrate to be processed in a processing container when a halogen-based gas is supplied into the processing container through a metal pipe.SOLUTION: A substrate processing method includes: a processing step of supplying a processing gas into a processing container in which a substrate is stored to process the substrate; a first step of supplying a halogen-based gas flowing through a metal pipe into the processing container; and a second step, performed before the first step, of supplying a basic gas including nitrogen in a molecule for generating a complex compound together with a metal constituting the pipe in the processing step, into the processing container and causing the basic gas to be absorbed into a wall surface in the processing container, or causing the basic gas to be absorbed into a porous body provided in a flow path formed by the pipe or into a partition member including a plurality of holes that partition the flow path in a flow path direction and communicate an upstream side and a downstream side of the flow path.SELECTED DRAWING: Figure 6

Description

[Technical Field]

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

[0002] In the manufacture of semiconductor devices, various processes are performed on substrates, such as semiconductor wafers (hereinafter referred to as wafers), stored in a processing chamber by supplying process gases, for example, through metal piping. This process gas may contain halogen-based gases, which may be corrosive to the piping. In such cases, metals constituting the piping may be supplied into the processing chamber together with the process gas, potentially contaminating the interior of the processing chamber and the substrates. Measures may be taken to prevent this metal contamination.

[0003] In the plasma processing apparatus disclosed in Patent Document 1, a halogen-based gas such as BCl3 is supplied into a processing vessel through a gas supply pipe having a stainless steel surface coated with a chromium passivation film. However, before supplying the gas into the processing vessel, the gas supply pipe is filled with gas to generate a reaction product containing chromium. The publication also describes a method of removing the halogen-based gas stored in the gas supply pipe together with the reaction product through a bypass line that bypasses the processing vessel (processing chamber). Patent Document 2 also describes the use of stainless steel pipes with Mn and Cu contents below specific values ​​when supplying halogen-based gases such as HF gas or ClF3 gas into the processing vessel. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2017-84882 [Patent Document 2] Japanese Patent Application Publication No. 2020-141039 Summary of the Invention [Problem to be solved by the invention]

[0005] The present disclosure provides a technique that can suppress metal contamination of a substrate being processed in a processing chamber when a halogen-based gas is supplied into the processing chamber through a metal pipe. [Means for solving the problem]

[0006] The substrate processing method of the present disclosure includes a processing step of supplying a processing gas into a processing vessel containing a substrate to process the substrate; a first step of supplying a halogen-based gas through a metal pipe into the processing vessel; a second step, which is carried out before the first step, of supplying a basic gas containing nitrogen in its molecules for generating a complex compound together with the metal constituting the piping in the treatment step into the treatment vessel and causing it to be adsorbed on the wall surface of the treatment vessel, or on a porous body provided in a flow path formed by the piping, or on a partition member having a plurality of holes that divides the flow path in the flow path direction and communicates the upstream side with the downstream side of the flow path; Equipped with. [Effects of the Invention]

[0007] The present disclosure can suppress metal contamination of substrates processed in a processing chamber when a halogen-based gas is supplied into the processing chamber through a metal pipe. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a vertical cross-sectional side view of an apparatus according to an embodiment of a substrate processing apparatus of the present disclosure. [Figure 2] FIG. 2 is a schematic view of the etching apparatus. [Figure 3] 5A and 5B are explanatory diagrams showing an etching method of a comparative example using the etching apparatus. [Figure 4] FIG. 2 is an explanatory diagram showing the etching method of the comparative example. [Figure 5]3A to 3C are explanatory diagrams showing an etching method according to an embodiment of the present invention using the etching apparatus. [Figure 6] FIG. 2 is an explanatory diagram showing the etching method of the embodiment. [Figure 7] FIG. 2 is an explanatory diagram showing the etching method of the embodiment. [Figure 8] FIG. 2 is an explanatory diagram showing the etching method of the embodiment. [Figure 9] FIG. 2 is an explanatory diagram showing the etching method of the embodiment. [Figure 10] FIG. 1 is a schematic diagram of a complex compound. [Figure 11] FIG. 10 is a vertical sectional side view showing another example of the substrate processing apparatus. [Figure 12] FIG. 10 is a vertical sectional side view showing yet another example of the substrate processing apparatus. [Figure 13] 5A to 5C are explanatory views showing the operation of the substrate processing apparatus. [Figure 14] 5A to 5C are explanatory views showing the operation of the substrate processing apparatus. [Figure 15] 5A to 5C are explanatory views showing the operation of the substrate processing apparatus. [Figure 16] 3 is a schematic view of a filter provided in the substrate processing apparatus; FIG. [Figure 17] 3 is a schematic view of a filter provided in the substrate processing apparatus; FIG. [Figure 18] 3 is a schematic view of a filter provided in the substrate processing apparatus; FIG. [Figure 19] 3 is a schematic view of a filter provided in the substrate processing apparatus; FIG. [Figure 20] FIG. 2 is a cross-sectional plan view showing piping provided in the substrate processing apparatus. [Figure 21] FIG. 10 is an explanatory diagram showing an image acquired in an evaluation test. [Figure 22] FIG. 10 is a graph obtained in an evaluation test. DETAILED DESCRIPTION OF THE INVENTION

[0009] [Configuration of the substrate processing apparatus] A substrate processing apparatus 1 according to one embodiment of the present disclosure will be described with reference to the vertical cross-sectional side view of Fig. 1. The substrate processing apparatus 1 is an etching apparatus that supplies a processing gas to a film 10 formed on the surface of a wafer W to etch the film. The film 10 is, for example, a Si (silicon) film. The processing gas (etching gas) is a halogen-based gas, and more specifically, for example, ClF3 (chlorine trifluoride) gas.

[0010] The substrate processing apparatus 1 includes a processing vessel 11. A transfer port 12 for a wafer W is opened in a sidewall of the processing vessel 11 and is opened and closed by a gate valve 13. A stage 14 for placing the wafer W is provided within the processing vessel 11, and the stage 14 is provided with lift pins (not shown). The wafer W is transferred between the stage 14 and a substrate transfer mechanism that moves in and out of the processing vessel 11 via the lift pins.

[0011] A temperature adjustment unit 15 is embedded in the stage 14, and adjusts the temperature of the wafer W placed on the stage 14. This temperature adjustment unit 15 is configured as a flow path that forms part of a circulation path through which a temperature adjustment fluid, such as water, flows, and adjusts the temperature of the wafer W by heat exchange with the fluid. However, the temperature adjustment unit 15 is not limited to such a fluid flow path and may be configured as, for example, a heater for resistance heating. Alternatively, the stage 14 may be configured as an electrostatic chuck, and the temperature adjustment unit 15 may be a heater provided in the electrostatic chuck.

[0012] Furthermore, a plurality of exhaust ports 21 are opened, for example, at the bottom of the processing vessel 11, and the upstream end of an exhaust pipe 22 is connected to each exhaust port 21. The downstream end of the exhaust pipe 22 is connected to an exhaust mechanism 24, for example, constituted by a vacuum pump, via a valve 23, which is a pressure change mechanism. By adjusting the opening of the valve 23, the exhaust flow rate in the processing vessel 11 is adjusted, and the pressure in the processing vessel 11 is set to a desired vacuum pressure.

[0013] The ceiling of the processing vessel 11 is configured as a shower head 20. The shower head 20 includes a shower plate 25 facing the stage 14, and gas supplied to a gas diffusion space 26 provided in the shower head 20 is discharged in a shower-like manner from outlets formed in the shower plate 25 toward the stage 14. The processing vessel 11 and the shower head 20 are made of a material different from that of piping 31, which will be described later, and specifically, are made of an aluminum alloy such as A5052 specified in the JIS standard.

[0014] The downstream ends of pipes 31 and 41 are connected to the upper part of the showerhead 20, and gas can be introduced into the gas diffusion space 26 from each of the pipes 31 and 41. The upstream side of the pipe 31 is connected to a ClF3 gas supply mechanism 32 via a valve V1. The supply mechanism 32 includes a reservoir for storing ClF3 gas, a valve, and a flow rate adjustment mechanism such as a mass flow controller for adjusting the flow rate of gas supplied from the reservoir to the downstream side of the pipe 31. Opening and closing the valve V1 switches between supplying and stopping the ClF3 gas into the processing vessel 11.

[0015] The pipe 31 is made of metal. More specifically, to prevent corrosion by ClF gas, the pipe 31 is made of stainless steel such as SUS316L according to the JIS standard, or Hastelloy. Therefore, in addition to iron or nickel, which are the main components, the pipe 31 also contains chromium (Cr) as an element constituting the pipe 31.

[0016] The upstream side of the pipe 41 is connected to a supply mechanism 42 for NH3 (ammonia) gas via a valve V2. The supply mechanism 42 has the same configuration as the supply mechanism 32, except that it supplies stored NH3 gas to the downstream side of the pipe 41 instead of ClF3 gas. Opening and closing the valve V2 switches between supplying and stopping the supply of NH3 gas into the processing vessel 11. This NH3 gas is a gas for suppressing contamination of the inside of the processing vessel 11 and the wafer W by Cr originating from the pipe 31, and its role will be described in detail later.

[0017] The substrate processing apparatus 1 also includes a control unit 100, which is a computer, and the control unit 100 includes a program, a memory, and a CPU. The program contains instructions (steps) for performing the aforementioned wafer W processing and wafer W transport. The program is stored on a storage medium, such as a compact disc, a hard disk, a magneto-optical disc, or a DVD, and is installed in the control unit 100. The control unit 100 outputs control signals to each component of the substrate processing apparatus 1 based on the program, thereby controlling the operation of each component. Specifically, the operations of the substrate processing apparatus 1 controlled in this manner include, for example, adjusting the temperature of the fluid supplied to the stage 14 (i.e., the processing temperature of the wafer W), opening and closing the valves V1 and V2 and controlling the operation of the supply mechanisms 32 and 42 to supply and cut off each gas into the processing chamber 11, and adjusting the exhaust flow rate using the valve 23 (i.e., adjusting the pressure inside the processing chamber 11).

[0018] [Treatment of Comparative Example] To clearly illustrate the effects of the embodiment, the processing of wafers W according to a comparative example will be described first with reference to process diagrams shown in FIGS. 2 to 4. In this comparative example, wafers W are sequentially transferred into the substrate processing apparatus 1 and processed without supplying NH3 gas into the processing vessel 11. For the purpose of explanation, the wafers W transferred into the processing vessel 11 and processed therein are sometimes numbered W1, W2, W3, etc. in accordance with their order. Note that in FIGS. 2 to 4 and FIGS. 5 to 9, which are process diagrams of the processing of the embodiment described below, the substrate processing apparatus 1 is shown in a simplified form compared to that shown in FIG. 1. In each diagram, ClF3 molecules, which are the etchant, are indicated as 51. A Cr compound (described later) is indicated as 52.

[0019] The wafer W1 is transferred into the processing chamber 11 and placed on the stage 21. The pressure inside the processing chamber 11 is adjusted to a predetermined level by exhausting the air from the exhaust port 21, and the temperature of the wafer W1 is also adjusted. ClF gas remains in the pipe 31 upstream of the valve V1. As described above, the pipe 31 is made of a metal that is relatively corrosion-resistant to ClF gas, but it is difficult to completely prevent corrosion. Therefore, the ClF gas remaining in the pipe 31 contains Cr compounds 52, which are reaction products of the ClF gas and the Cr constituting the pipe 31. The Cr compounds 52 are, for example, chromium fluoride (CrFx) or chromium oxyfluorides such as CrO2F2 and CrF3O. These compounds are derived from the Cr in the pipe 31 and the fluorine in the ClF3 molecules 51, and are in a gaseous state in the pipe.

[0020] Valve V1 is opened, and ClF gas is supplied from pipe 31 into processing vessel 11 via shower head 20, starting the etching process (step S11, FIG. 2). ClF molecules 51 etch the film 10 on the surface of wafer W1. The Cr compounds 52 described above also flow toward processing vessel 11 along with the ClF gas, and at this time, the Cr compounds 52 are adsorbed onto the wall surfaces of processing vessel 11 and wafer W. The wall surfaces of processing vessel 11 specifically refer to the surface of stage 14, which is a structure within processing vessel 11, and the inner wall surfaces of processing vessel 11. The inner wall surfaces of processing vessel 11 more specifically refer to the side, bottom, and ceiling surfaces of processing vessel 11 (i.e., the underside of shower plate 25).

[0021] The following additional information is provided regarding the presumed adsorption of the Cr compound 52. The Cr compound 52 is supplied from the piping 31 into the processing vessel 11 via the showerhead 20, but the flow path within the showerhead 20 is relatively narrow. Due to the influence of changes in the ambient pressure as the Cr compound 52 passes through such a narrow flow path, some of the Cr compound 52 changes from a gaseous state to a solid. Specifically, the Cr compound 52 either changes from a gaseous state to a solid while maintaining the original composition of the Cr compound 52, or changes into a Cr compound 52 with a different composition from the original Cr compound 52 and then solidifies. By becoming a solid, the Cr compound 52 is presumably adsorbed onto the wafer W and the wall surfaces within the processing vessel 11 before reaching the exhaust port 21. Because the Cr compound 52 is a solid, it is less likely to flow toward the exhaust port 21 than the Cr compound 52 in a gaseous state. Furthermore, unlike the complexes described below, the Cr compound 52 has a relatively small molecular size, making it less likely to be swept away by the exhaust flow within the processing vessel 11. Therefore, the Cr compound 52 is presumably retained while adsorbed onto the wafer W1 and the wall surfaces within the processing vessel 11.

[0022] After a predetermined time has elapsed since the valve V1 was opened, the valve V1 is closed, the supply of ClF gas into the processing vessel 11 is stopped, and the etching process of the wafer W is completed (step S12, FIG. 3). Then, the wafer W1 is unloaded from the processing vessel 11. At this time, Cr compounds 52 remain adsorbed on the wafer W1 and the wall surfaces of the processing vessel 11. In the piping 31, Cr compounds 52 are newly generated due to the accumulation of ClF gas.

[0023] Thereafter, wafer W2 is transferred into processing chamber 11, and similarly to the processing of wafer W1, the temperature and pressure in processing chamber 11 are adjusted by placing wafer W2 on stage 14. Then, valve V1 is opened to supply ClF gas into processing chamber 11 via shower head 20, and etching processing is initiated. That is, step S11 described above is performed again (FIG. 4).

[0024] Similarly to wafer W1, wafer W2 is also subjected to etching of film 10 using ClF gas. Meanwhile, new Cr compounds 52 are supplied into processing vessel 11 from pipe 31, and wafer W2 is adsorbed with the Cr compounds 52 newly supplied from pipe 31 and the Cr compounds 52 desorbed from the wall surfaces of processing vessel 11. Furthermore, the Cr compounds 52 supplied from pipe 31 are adsorbed onto the wall surfaces of processing vessel 11, thereby increasing the amount of Cr on the wall surfaces. Thereafter, valve V1 is closed, and the etching process for wafer W is completed. That is, the operation of step S12 described above is performed again. Thereafter, wafer W2 is unloaded from processing vessel 11.

[0025] After this, wafers W3, W4, W5, etc. are sequentially transferred into the substrate processing apparatus 1, and steps S11 and S12 are performed for each wafer. That is, a cycle consisting of steps S11 and S12 (referred to as cycle A' for convenience) is repeated, thereby etching each wafer W in turn. As the processing in the apparatus progresses as described above, Cr compounds 52 are supplied into the processing vessel 11 from the piping 31 each time cycle A' is performed. Therefore, when wafers W are repeatedly processed by repeating cycle A' in this manner, the amount of Cr compounds 52 adsorbed on the wall surface of the processing vessel 11 increases as the number of cycle A' executions increases. In other words, Cr contamination in the processing vessel 11 progresses. Therefore, the amount of Cr contamination increases for wafers W processed later in the processing sequence, and there is a risk that the amount of contamination may exceed the allowable range.

[0026] As described above, even if the pipe 31 is made of a material that has a relatively high corrosion resistance against ClF3 gas, it is difficult to completely prevent corrosion by the ClF3 gas and prevent the formation of Cr compounds 52. Note that, in order to obtain high corrosion resistance against the gas that flows through it, a coating technique is known in which a film made of a material such as PTFE is formed on the surface of the pipe, and it is conceivable that this coating could be used to address the problems of the comparative example described above.

[0027] However, the pipe 31 may be relatively long, such as when it is routed over a relatively long distance in a factory building where the substrate processing apparatus 1 is installed. When the pipe 31 is formed over such a long distance, it is formed by welding multiple pipes together, making it difficult to apply a coating to the welded joints. Another possible solution is to supply fluorine (F2) gas into the pipe 31 to form a passivation film on the surface of the pipe 31. However, it is difficult to form a passivation film even at a relatively low temperature, and high-temperature processing is time-consuming. Even with these coatings and passivation film formation methods, it is difficult to completely prevent corrosion of the pipe 31.

[0028] As mentioned above, Patent Document 1 describes a method in which gas that accumulates in a piping system and contains substances that contaminate the processing vessel is disposed of by supplying the gas to a bypass line connected to the piping system, thereby avoiding supply into the processing vessel 11, and then introducing the gas into the processing vessel through the piping. However, as mentioned above, the piping 31 of the substrate processing apparatus 1 can be relatively long. If an attempt is made to remove the ClF gas accumulated in the piping 31 from the piping 31 through a bypass line, a large amount of ClF gas will be disposed of, which increases the operating costs of the apparatus. Therefore, a solution other than exhausting the ClF gas through the bypass line is required.

[0029] Incidentally, ClF3 undergoes a relatively strong exothermic reaction with moisture adsorbed on the surface of pipe 31, damaging the surface of pipe 31, and it is believed that the above-mentioned Cr compound 52 is generated as a result of this exothermic reaction. Therefore, it is conceivable to address the problem described in the comparative example by, for example, passing N2 gas through pipe 31 as a purge gas to remove moisture from the surface of pipe 31 and thereby prevent the formation of Cr compound 52. However, there is a limit to the amount of moisture that can be removed from the surface of pipe 31 by this purging. In addition, N2 gas itself contains moisture. Therefore, since adsorption of moisture onto the surface of pipe 31 is unavoidable, other effective countermeasures are required.

[0030] Purifiers are known that adsorb and remove moisture and metals contained in gas flowing through a flow path. However, as described above, ClF gas has the property of reacting violently with water, making it difficult to install such a purifier in the pipe 31 through which the ClF gas flows. Therefore, a different solution is required.

[0031] [Treatment of the Example] The substrate processing apparatus 1 is configured to perform processing that can address the above-mentioned problems. Taking this processing as the processing of the embodiment, the outline of the processing is that NH3 gas is supplied before ClF3 gas is supplied into the processing vessel 11. As will be explained in the evaluation test described later, it has been confirmed that the processing of this embodiment suppresses Cr contamination of the wafers W.

[0032] This is presumably due to the following mechanism. NH3 gas molecules are adsorbed onto the wall surface inside the processing vessel 11, and when Cr compound 52 gas is supplied into the processing vessel 11 together with ClF3 gas, they react with the Cr compound 52. Then, a metal complex compound consisting of Cr, which is a metal constituting the pipe 31, NH3, and halogens constituting the processing gas is generated. In FIGS. 5 to 9, which explain the examples, NH3 molecules are shown as 53, and the metal complex compound consisting of Cr, NH3, and halogens is shown as Cr complex compound 54. A specific example of the Cr complex compound 54 is (NH4)3CrF6.

[0033] The Cr complex compound 54 has a relatively large molecular weight and is therefore believed to be solid in the processing vessel 11. However, since the molecular size of the Cr complex compound 54 is relatively large due to its complex form, it is believed to be more likely to be swept away by the air current in the processing vessel 11 and to flow into the exhaust port 21 than the solid Cr compound 52. This is presumably why the evaluation test resulted in the suppression of Cr contamination as described above.

[0034] 5 to 9, the process of the example will be specifically described below, focusing on the differences from the process of the comparative example. First, with the process vessel 11 evacuated to a predetermined pressure, valve V2 is opened to supply NH3 gas into the process vessel 11, and NH3 molecules 53 are adsorbed onto the wall surface of the process vessel 11 (step S1, FIG. 5). As described above, the wall surface of the process vessel 11 includes not only the inner wall surface of the process vessel 11 but also the surfaces of structures within the process vessel 11, such as the surface of the stage 14.

[0035] Valve V2 is closed to stop the supply of NH3 gas into processing vessel 11. Thereafter, wafer W1 is loaded into processing vessel 11 and placed on stage 14. The temperature of wafer W1 is adjusted, while the pressure inside processing vessel 11 is adjusted to a predetermined level. Next, valve V1 is opened, and ClF3 gas is supplied from pipe 31 into processing vessel 11, starting an etching process using ClF3 molecules 51 in the gas (step S2, FIG. 6). That is, similar to step S11 of the comparative example, etching of film 10 on the surface of wafer W1 starts.

[0036] While etching of the film 10 progresses, Cr compounds 52 supplied into the processing vessel 11 together with the ClF gas react with NH molecules 53 adsorbed on the wall surface of the processing vessel 11 to form Cr complex compounds 54. The Cr complex compounds 54 are carried by the exhaust flow in the processing vessel 11 to the exhaust port 21 and are removed from the processing vessel 11. As described above, the removal of Cr from the processing vessel 11 is promoted, thereby suppressing Cr contamination of the wafer W1, and the film 10 is etched. Note that the generation of the Cr complex compounds 54 reduces the amount of NH molecules 53 adsorbed on the wall surface.

[0037] The valve V1 is closed to stop the supply of ClF gas from the pipe 31 into the processing vessel 11, and the etching process ends similarly to step S12 in the comparative example (step S3, FIG. 7). The processing vessel 11 continues to be evacuated, so that the Cr complex compound 54 is continuously discharged from the processing vessel 11, while the wafer W1 is unloaded from the processing vessel 11.

[0038] Thereafter, with the interior of the processing vessel 11 maintained at a predetermined pressure, valve V2 is opened to supply NH gas into the processing vessel 11. Therefore, step S1 described above is executed again. NH molecules 53 in this gas react with Cr compounds 52 still adsorbed and remaining on the wall surfaces of the processing vessel 11 to generate Cr complex compounds 54, which are then removed from the processing vessel 11 by exhaust from the exhaust port 21 (FIG. 8). The NH molecules 53 are also adsorbed onto the wall surfaces of the processing vessel 11, increasing the amount of NH molecules 53 adsorbed on the wall surfaces.

[0039] Valve V2 is closed to stop the supply of NH3 gas into processing vessel 11. Thereafter, wafer W2 is loaded into processing vessel 11, and similarly to the loading of wafer W1, the temperature of wafer W2 is adjusted by placing it on stage 14, and the temperature inside processing vessel 11 is also adjusted. Then, valve V1 is opened, and ClF3 gas is supplied from pipe 31 into processing vessel 11 to perform etching. Therefore, step S2 described above is executed again (FIG. 9).

[0040] As in the etching process of wafer W1, Cr contained in Cr compounds 52 supplied into process vessel 11 together with ClF gas forms Cr complex compounds 54 with NH molecules 53 adsorbed on the wall surface of process vessel 11, and these Cr complex compounds 54 are removed from process vessel 11. As described above, Cr compounds 52 are removed from process vessel 11 by the action of NH gas before step S2 is performed, and the removal of Cr compounds 52 is promoted during the etching process after the start of step S2. As a result, Cr contamination of wafer W2 is also suppressed, and etching of film 10 progresses.

[0041] Thereafter, valve V1 is closed, and the etching process ends. That is, step S3 is executed again. Wafers W3, W4, W5, etc. are sequentially transferred into the substrate processing apparatus 1, and steps S1 to S3 are performed for each wafer. That is, a cycle consisting of steps S1 to S3 (referred to as cycle A for convenience) is repeated, and the etching process is performed on each wafer W in turn. As with wafer W2, each of wafers W3, W4, W5, etc. is transferred into processing vessel 11 in a state in which removal of Cr compounds 52 that had been adsorbed in processing vessel 11 during processing of the wafer W previously transferred into processing vessel 11 has progressed due to the action of NH3 gas, and removal of Cr from processing vessel 11 is promoted during processing. Therefore, Cr contamination of each of wafers W3, W4, W5, etc. is suppressed.

[0042] As described above, according to the process of the embodiment in which cycle A is repeated, when etching each wafer W using ClF gas, NH gas is supplied into processing vessel 11 before ClF gas is supplied into processing vessel 11, and NH molecules 53 are adsorbed onto the wall surface of processing vessel 11. As a result, Cr in Cr compound 52 supplied together with ClF gas becomes Cr complex compound 54, which facilitates removal from processing vessel 11, thereby suppressing Cr contamination in processing vessel 11 and Cr contamination of wafers W.

[0043] In the above cycle A, NH3 gas is supplied into the processing vessel 11 before each wafer W is loaded into the processing vessel 11, but the timing of supplying NH3 gas into the processing vessel 11 is not limited to this. Specifically, NH3 gas may be supplied into the processing vessel 11 while the wafer W is stored in the processing vessel 11.

[0044] 8 and 9, there is a risk that Cr compounds 52 may remain adsorbed on the wall surfaces of the processing vessel 11 even after the wafer W after etching is removed. To prevent these Cr compounds 52 from being adsorbed onto the wafer W to be subsequently transferred into the processing vessel 11 and processed, and to further reduce contamination of the wafer W, it is preferable to supply NH3 gas before transferring the wafer W into the processing vessel 11, as in the above-described cycle A. Therefore, it is more preferable to supply NH3 gas into the processing vessel 11 when the wafer W is not stored in the processing vessel 11.

[0045] In the process of the embodiment in which cycle A is repeated, NH3 gas is supplied to the processing vessel 11 as pretreatment for each wafer W processed. However, the supply of NH3 gas is not limited to this. Specifically, for example, a cycle of supplying NH3 gas into the processing vessel 11 and then etching multiple wafers W may be repeated. That is, after performing step S1, steps S2 and S3 may be performed multiple times, and then step S1 may be performed again, followed by steps S2 and S3 multiple times. However, in order to reliably suppress Cr contamination of each wafer W, it is preferable to supply NH3 gas as pretreatment for each wafer W processed, as in cycle A.

[0046] However, even if excessive evacuation occurs (i.e., the pressure inside the processing vessel 11 drops excessively) between the time valve V2 is opened to supply NH3 gas into the processing vessel 11 and the time valve V1 is opened to start supplying ClF3 gas, the NH3 molecules adsorbed on the wall surface inside the processing vessel 11 are not completely desorbed, and the effect of suppressing Cr contamination by NH3 has been confirmed.

[0047] The pipe 31 contains Cr as a transition metal, and the process of the embodiment has been described as suppressing contamination by this Cr. However, even if the pipe 31 contains a transition metal other than Cr and a compound containing the transition metal other than Cr is supplied into the process vessel 11 using ClF gas, the process of the embodiment described above can form a complex of the transition metal and promote its removal from the process vessel 11. In other words, this technology can also suppress contamination by transition metal elements other than Cr that belong to groups 3 to 12 of the periodic table. Specifically, contamination by manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), etc. can be suppressed.

[0048] The film 10 to be etched is not limited to a Si film. Depending on the material of the film 10, an appropriate type of gas, such as HF (hydrogen fluoride) gas or F2 gas, may be selected as the halogen-based gas flowing through the pipe 31. The halogen-based gas may be a compound gas composed of a halogen element and other elements, such as HF gas, or a gas composed only of a halogen element, such as F2 gas. The halogen-based gas used is not limited to the above-described fluorine-based gas (a gas containing fluorine as a constituent element), and the present technology can also be applied to gases that do not contain fluorine as a constituent element but contain a halogen element other than fluorine, such as bromine.

[0049] However, when ClF gas is passed through the pipe 31, a violent reaction occurs between the ClF gas and the pipe 31 due to the moisture adsorbed on the wall surface of the pipe as described above, and during this reaction, a relatively large amount of Cr compounds 52 is produced due to the Cr constituting the pipe 31. Therefore, as described above, this technique is particularly effective in suppressing Cr contamination inside the processing vessel 11 and on the wafers W when ClF gas is passed through the pipe 31 made of Cr.

[0050] When NH3 reacts with Cr to produce the Cr complex compound 54, a coordinate bond is formed between Cr and NH3 through the lone electron pair of the nitrogen atom contained in NH3, forming a complex ion, as shown in Figure 10. This complex ion bonds with fluorine, a constituent element of ClF3 gas, forming a Cr complex compound 54, such as the example (NH4)3CrF6. A gas that, like NH3, contains nitrogen with a lone electron pair in its molecule and thus has basicity (i.e., can bond with hydrogen ions) may be used instead of NH3 gas to form the Cr complex compound. In other words, the gas that can be used to produce a Cr complex compound and promote Cr removal is not limited to NH3 gas.

[0051] Specific examples of usable gases include using various amine gases such as trimethylamine instead of NH3 gas to form a complex compound of Cr, thereby suppressing Cr contamination inside the processing chamber 11 and on the wafer W. As described above, as long as nitrogen has a lone pair of electrons, primary to tertiary amines can be used. While it has been mentioned that NH3 gas can form complexes with transition metals other than Cr, the same is true for amine gases. That is, even when a pipe 31 containing a relatively large amount of transition metals other than Cr is used to suppress contamination inside the processing chamber 11 and on the wafer W due to the transition metals, amine gas can be used instead of NH3 gas.

[0052] [Another example of the device configuration] However, the present technology is not limited to application to substrate processing apparatuses that etch wafers W. FIG. 11 shows a vertical cross-sectional side view of a substrate processing apparatus 1A as another example of a substrate processing apparatus. The substrate processing apparatus 1A forms any film on the wafer W by CVD by supplying a film formation gas to the wafer W. The differences between the substrate processing apparatus 1A and the substrate processing apparatus 1 will be described mainly with respect to the following: a downstream end of a pipe 61 is connected to the top of the shower head 20, and an upstream end of the pipe 61 is connected to a supply mechanism 62 for a film formation gas via a valve V3. Except for the fact that the film formation gas is stored in the supply mechanism 62, the supply mechanism 62 has the same configuration as the supply mechanism 32 for ClF3 gas.

[0053] Like the substrate processing apparatus 1, the substrate processing apparatus 1A also continuously evacuates the processing chamber 11 during operation. The substrate processing apparatus 1A performs a film formation process by supplying a film formation gas to wafers W transferred to the substrate processing apparatus 1A. During this process, films are formed not only on the surfaces of the wafers W but also on the wall surfaces of the processing chamber 11. After a predetermined number of wafers W have been formed, NH3 gas is supplied into the processing chamber 11 and adsorbed onto the wall surfaces of the processing chamber 11. Then, ClF3 gas is supplied into the processing chamber 11 as a cleaning gas to perform a cleaning process to remove the film on the wall surfaces of the processing chamber 11. During this process, Cr compounds 52 are supplied into the processing chamber 11. Similar to the etching process in the substrate processing apparatus 1, the Cr compounds 52 react with the adsorbed NH3 gas to form Cr complex compounds 54, facilitating their removal from the processing chamber 11. As a result, Cr contamination of wafers W processed after this cleaning process is suppressed.

[0054] As described above, the ClF gas flowing through the pipe 31 is not limited to being a processing gas for processing the wafer W. The cleaning process is performed in a state where the wafer W is not stored in the processing vessel 11. As in the substrate processing apparatus 1, the wafer W may or may not be stored in the processing vessel 11 in the substrate processing apparatus 1A when the NH gas is supplied.

[0055] [Another Configuration Example of Etching Apparatus] As described above, a method for suppressing contamination by transition metals such as Cr by supplying NH3 gas into the processing vessel 11 to form a complex has been described. However, the formation of the complex by supplying NH3 gas is not limited to being performed inside the processing vessel 11. A configuration in which a porous body (porous body), for example, a filter, is provided in the gas supply piping upstream of the showerhead 20, and the complex is formed and collected in the filter, can also be used. An example of such a configuration, substrate processing apparatus 1B, will be described with reference to the vertical cross-sectional side view of FIG. 12, focusing on the differences from the substrate processing apparatus 1.

[0056] The downstream end of pipe 71, in addition to the downstream ends of pipes 31 and 41, is connected to the upper portion of shower head 20 of substrate processing apparatus 1B, which is an etching apparatus. Gas can be introduced into gas diffusion space 26 from pipe 71 and supplied into processing chamber 11. A valve V4 and a filter 70 are installed in this order upstream of pipe 71. Thus, the filter 70 is installed in the flow path formed by pipe 71. Pipe 71 branches upstream of the filter 70 to form pipes 72 and 73. Valves V5 and V6 are installed in pipes 72 and 73, respectively, and the upstream ends of pipes 72 and 73 are connected to pipes 31 and 41, respectively. In this example, ClF gas flows through pipes 71 and 72 in addition to pipe 31. Therefore, like pipe 31, at least pipes 71 and 72 are made of a metal that is resistant to corrosion by ClF gas, such as SUS316L. Therefore, the metals constituting the pipes 71 and 72 include Cr.

[0057] Furthermore, filters 70 are also installed in the pipes 31 and 41, upstream of the valves V1 and V2 and downstream of the positions where the pipes 72 and 73 are connected, respectively. Each filter 70 captures foreign matter contained in the gas and prevents the foreign matter from being supplied into the processing vessel 11. Although filters 70 are not shown in the pipes of the substrate processing apparatus shown in FIG. 1 and other figures, filters 70 may also be installed in the pipes. Hereinafter, the filters 70 installed in the pipes 31, 41, and 71, respectively, may be referred to as 70A, 70B, and 70C to distinguish them from one another. Filters 70A and 70C, through which ClF gas flows, are made of ceramics such as Al2O3 (aluminum oxide) to suppress corrosion.

[0058] A pressure gauge 74 is provided in the pipe 71 at a position between the filter 70C and the valve V4, and the upstream end of an exhaust pipe (hereinafter referred to as a bypass exhaust pipe) 75 is connected to the pressure gauge 74. The pressure gauge 74 transmits a detection signal corresponding to the pressure in the flow path within the pipe 71 at that position to the control unit 100, and the control unit 100 can detect the pressure in that flow path from the detection signal. A valve V7 is provided in the bypass exhaust pipe 75, and the downstream end of the bypass exhaust pipe 75 is connected to the downstream side of the valve 23 in the exhaust pipe 22. Therefore, the exhaust path formed by the bypass exhaust pipe 75 is connected to the filter 70C via the flow path within the pipe 71.

[0059] Then, by opening the valve V7, the exhaust mechanism 24 can exhaust the piping 71 and the filter 70C (more specifically, the flow path within the filter 70C) via the bypass exhaust pipe 75 without passing through the processing vessel 11. As described above, since the filter 70C is a porous body, the flow path within the filter 70C is formed by holes 79 (not shown in FIG. 12 ) in the porous body.

[0060] Next, the operation of the substrate processing apparatus 1B will be described with reference to Figures 13 to 15, which are schematic diagrams of vertical cross sections of the substrate processing apparatus 1B. Figures 13 to 15 show the open and closed states of valves V1, V2, V4 to V7, with closed valves indicated by diagonal lines and open valves indicated without diagonal lines. Regarding the pipes supplying gases to the showerhead 20 and the bypass exhaust pipe 75, portions through which gas is flowing are shown thicker than portions through which gas is not flowing. The description will also refer to Figures 16 to 19, which are schematic diagrams showing the vertical cross section of the filter 70C, as appropriate.

[0061] First, a wafer W is transferred into the processing chamber 11 with all valves closed. At this time, for example, a relatively long time has passed since the previous processing of the wafer W, and a relatively large amount of Cr compounds 52 may be contained in the pipes 31, 71, and 72 due to the accumulation of ClF gas. Then, as shown in FIG. 13, the valves V6 and V7 are opened, and NH gas from the supply mechanism 42 passes through the filter 70C and is exhausted via the bypass exhaust pipe 75. As the NH gas flows in this manner, NH molecules 53 are adsorbed onto the wall surface 78 forming the pores 79 of the filter 70C (FIG. 16). Because the filter 70C is porous, its surface area per unit volume is relatively large. Therefore, a relatively large amount of NH molecules 53 are adsorbed and retained on the filter 70C.

[0062] Next, as shown in FIG. 14, valve V6 is closed, stopping the supply of NH gas from the supply mechanism 42 to the filter 70C. By evacuating the filter 70C via the bypass exhaust pipe 75, some of the adsorbed NH molecules 53 are desorbed from the wall surface 78 and removed from the filter 70C (FIG. 17). While valve V6 is open and the filter 70C is being evacuated, the control unit 100 monitors the pressure in the pipe 71, detected based on the detection signal output from the pressure gauge 74. When the pressure drops below a predetermined pressure, it is determined that the desorption of the NH molecules 53 has progressed sufficiently and the amount of NH molecules 53 adsorbed on the filter 70C has become appropriate, and valve V7 is closed, stopping the evacuation of the filter 70C. The reason for removing some of the NH adsorbed on the filter 70C in this manner is to prevent excessive heat generation in the filter 70C due to an excessive reaction between NH and ClF when ClF gas is later passed through the filter 70C.

[0063] 15, valves V4 and V5 are opened, and the ClF gas remaining in the pipes 31, 71, and 72 is supplied to the wafer W through the filter 70C. Cr compounds 52 contained in the ClF gas react with NH molecules 53 adsorbed on the filter 70 to produce solid Cr complex compounds 54 (FIG. 18). Cr complex compounds 54, which have a relatively large molecular size, cannot pass through holes 79 in the filter 70 and are prevented from being supplied into the processing chamber 11. That is, the Cr compounds 52 are collected in the filter 70 as the Cr complex compounds 54 (FIG. 19). After the film 10 on the surface of the wafer W is etched by the ClF gas, valves V4 and V5 are closed, and the wafer W is unloaded from the processing chamber 11.

[0064] Because NH3 and ClF3 react violently with each other, if these gases are simultaneously flowed toward filter 70C and allowed to merge, there is a risk of fire or an excessively exothermic reaction occurring. Therefore, as shown in Figures 13 to 15, NH3 gas and ClF3 gas are not supplied simultaneously, but are supplied sequentially to filter 70C. Furthermore, as described above, filter 70C is evacuated under monitoring by pressure gauge 74, and the amount of NH3 gas adsorbed by filter 70C is adjusted. This more reliably suppresses fire or an excessively exothermic reaction when ClF3 gas flows through filter 70C, while capturing Cr compounds 52 as Cr complex compounds 54.

[0065] 13, when NH gas is adsorbed to the filter 70C, the NH gas that has passed through the filter 70C is exhausted via the bypass exhaust pipe 75, thereby not passing through the processing vessel 11. Even when adjusting the amount of NH gas adsorbed by the filter 70C, the exhaust flow does not pass through the processing vessel 11, as shown in FIG. 14, by using the bypass exhaust pipe 75 for exhaust, as shown in FIG. 13. Before NH gas is supplied, ClF gas remains upstream of the position where the bypass pipe 75 is connected to the pipe 71 where the filter 70C is installed, as shown in FIG. 13. This ClF gas was previously supplied to the pipe 71 when processing wafers W transferred to the processing vessel 11. Because ClF gas remains in this manner, Cr compounds 52 may be present upstream of the pipe 71. However, by adjusting the adsorption amount of NH3 gas onto the filter via the bypass exhaust pipe 75 in this manner, it is possible to prevent the Cr compound 52 from being supplied to the processing vessel 11 and contaminating the inside of the processing vessel 11.

[0066] In the substrate processing apparatus 1B, the pipes are configured as described above, so that NH3 gas and ClF3 gas can be supplied into the processing vessel 11 without passing through the filter 70C by opening and closing the valves V1 and V2. Therefore, by performing steps S1 to S3 described in the description of the substrate processing apparatus 1, it is also possible to supply ClF3 gas into the processing vessel 11 to which NH3 has been adsorbed, and process the wafers W.

[0067] For the purposes of explanation, wafers W that are successively transferred and processed in the substrate processing apparatus 1B are referred to as wafers W1 and W2. Depending on the length of time L1 from when the supply of ClF gas to wafer W1 is terminated to when wafer W is loaded into the processing chamber 11, the processes of steps S1 to S3 and the process using filter 70C shown in FIGS. 13 to 15 may be used interchangeably. Specifically, for example, when the length of time L1 is relatively long and equal to or greater than a predetermined set value, it is assumed that a large amount of Cr compounds 52 are retained in the piping, and the Cr compounds 52 are collected by filter 70C described with reference to FIGS. 13 to 15 to prevent the Cr compounds 52 from being supplied into the processing chamber 11. When the length of time L1 is shorter than the set value, steps S1 to S3 may be performed to suppress Cr contamination in the processing chamber 11.

[0068] In describing the effects of the substrate processing apparatus 1B, it has been described that Cr contamination in the processing vessel 11 is suppressed by capturing Cr compounds 52 in filter 70C, but each transition metal other than Cr exemplified in the description of the substrate processing apparatus 1 is also captured in the same manner as Cr. Therefore, contamination in the processing vessel 11 by metals other than Cr is suppressed in the same manner as contamination in the processing vessel 11 by Cr.

[0069] The filter 70C is detachable from the pipe 71, and can be removed from the pipe 71 as needed for maintenance such as replacement or cleaning. For example, this maintenance may be performed periodically by an operator. A plurality of pipes 71 are provided, each of which includes the filter 70C, and each of which includes pipes 72 and 73 with valves V5 and V6 attached to the pipe 71, and a bypass exhaust pipe 75 with valve V7. While the filter 70C is detached from any of the plurality of pipes 71, the filter 70C and bypass exhaust pipe 75 of the other pipes 71 may be used to perform the operations described with reference to FIGS. 13 to 15.

[0070] 20 shows a cross-sectional plan view of pipe 71. Instead of filter 70C being interposed in pipe 71 shown in Fig. 20, mesh 76 is provided to separate the flow path in pipe 71 into an upstream side and a downstream side. Therefore, mesh 76 is provided in the flow path formed by pipe 71 as a partition member that separates the flow path in the flow path direction. Mesh 76 also has a relatively large surface area per unit volume, so that many NH3 molecules 53 can be adsorbed, and Cr compounds 52 can be converted to Cr complex compounds 54 on the surface of mesh 76.

[0071] If the mesh size of the mesh 76 (i.e., the holes formed by the mesh 76) is relatively large, the Cr complex compound 54 will not be trapped by the mesh 76 but will be supplied into the processing vessel 11. However, even in this case, as described in the first embodiment, the Cr complex compound 54 is easily removed from the processing vessel 11 by being carried by the exhaust flow formed in the processing vessel 11, and therefore, Cr contamination is reduced.

[0072] Furthermore, instead of a mesh, a member having a large number of holes, such as a punched plate, may be provided to separate the flow path of the pipe 71. As described above, the flow path of the pipe 71 is not limited to being provided with a porous body, and a partition member having a plurality of holes, such as a mesh or punched plate, may be provided to separate the flow path formed by the pipe 71 into an upstream side and a downstream side and to communicate the upstream side and downstream side of the flow path.

[0073] Although the foregoing description has been given using wafers as an example of the substrate to be processed, substrates processed in the processing chamber 11 include, in addition to wafers, substrates used in manufacturing flat panel displays, substrates used in manufacturing exposure masks used in photolithography, and dummy substrates processed for the purpose of testing or setting processing parameters in the substrate processing apparatus. Furthermore, the embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The above-described embodiments may be omitted, substituted, modified, or combined in various ways without departing from the scope and spirit of the appended claims.

[0074] [Evaluation test] The evaluation tests conducted in relation to this technology will be described below. Evaluation Test 1 A pipe made of SUS316L was kept at 35°C and ClF gas was passed through the pipe for 100 hours. After the flow of ClF gas was stopped, the surface condition of the inner wall of the pipe was observed. Note that no passivation film was formed on the pipe by passing F gas through it.

[0075] Figure 21 is an image of the inner wall of this pipe, and it can be seen that there are areas where the surface condition has been significantly altered. Figure 22 is a graph showing the results of XPS (X-ray photoelectron spectroscopy) performed on this altered area. Note that in Figure 13, the measurement results for some elements, such as Mo, which were detected in trace amounts at each depth, are not shown.

[0076] As shown in the graph of Figure 21, the surface layer of the inner wall has a higher amount of fluorine atoms and oxygen atoms than the deeper portion, while the amount of Cr is lower. Therefore, it is presumed that a chemical reaction occurred between oxygen, ClF3, and Cr contained in moisture adsorbed on the piping. It is also presumed that the Cr that constituted the piping was carried away by the ClF3 gas as a product of the chemical reaction. Therefore, when ClF3 gas is supplied into the processing vessel 11 by flowing it through the piping 31 as described in the embodiment, it is necessary to take measures to prevent Cr contamination inside the processing vessel 11.

[0077] As shown in FIG. 21, significant roughness was visually observed on the inner wall of the piping after ClF gas was passed through. This roughness was considered to be greater than that which would occur if another halogen-based gas, such as F gas, were passed through the piping instead of ClF gas. In other words, the test results confirmed that when ClF gas was passed through the SUS316L piping, many Cr compounds flowed downstream of the piping. Therefore, as described in the embodiment, when ClF gas was passed through the piping 31 made of Cr, a relatively large amount of Cr compounds 52 was likely to be supplied into the processing vessel 11. This technology can promote the removal of such a large amount of Cr compounds 52 from the processing vessel 11 by ClF gas, and is therefore particularly effective when ClF gas is used.

[0078] Evaluation Test 2 In evaluation test 2, substrates B1, B2, and B3 were transported in this order to the substrate processing apparatus 1 and subjected to processing in which ClF gas was supplied. However, substrate B1 was subjected to processing in steps S11 and S12 of the comparative example described with reference to Figures 2 to 4, and substrates B2 and B3 were subjected to processing in steps S1 to S3 of the example described with reference to Figures 5 to 9. Therefore, NH3 gas was supplied into the processing vessel 11 before etching each of substrates B2 and B3, but NH3 gas was not supplied into the processing vessel 11 before etching substrate B1.

[0079] After the processing, the substrates B1 to B3 were removed from the processing vessel 11 and their surfaces were cleaned with a predetermined amount of cleaning liquid. The cleaning liquid was collected and the amount of metal elements contained in the cleaning liquid was measured by inductively coupled plasma mass spectrometry. Therefore, the measured value reflects the environment inside the processing vessel 11. Table 1 below shows the results of evaluation test 1, and the values ​​in the table are the measurement results (unit: atoms / cm 2 ) by a predetermined positive number. Therefore, the larger the value shown in the table, the larger the actual measured amount.

[0080] [Table 1]

[0081] As shown in Table 1, unlike other elements, the measured amount of Cr was in the order of substrate B1 > substrate B2 > substrate B3, resulting in a decrease in the measured value each time a substrate was processed. It is believed that this result was due to the fact that, after processing of substrate B1, NH3 was supplied, which promoted the discharge of Cr from the processing vessel 11 through the generation of Cr complex compound 54, as described in the embodiment. As described above, the results of evaluation test 2 demonstrated the effectiveness of the present technology. [Explanation of symbols]

[0082] W Semiconductor wafer 11 Processing container 31 Piping 51 ClF3 molecules 52 NH3 molecule 54 Cr complex compounds

Claims

1. a processing step of supplying a processing gas into a processing vessel containing a substrate to process the substrate; a first step of supplying a halogen-based gas through a metal pipe into the processing vessel; a second step, which is carried out before the first step, of supplying a basic gas containing nitrogen in its molecules for generating a complex compound together with the metal constituting the piping in the treatment step into the treatment vessel and causing it to be adsorbed on the wall surface of the treatment vessel, or on a porous body provided in a flow path formed by the piping, or on a partition member having a plurality of holes that divides the flow path in the flow path direction and communicates the upstream side with the downstream side of the flow path; A substrate processing method comprising:

2. 2. The substrate processing method according to claim 1, wherein the basic gas is an ammonia gas or an amine gas.

3. the processing gas is the halogen-based gas flowing through the metal pipe, 3. The substrate processing method according to claim 2, wherein the processing step is an etching step of etching a film formed on the substrate with the halogen-based gas.

4. 4. The substrate processing method according to claim 3, wherein the halogen-based gas is a fluorine-based gas.

5. the halogen-based gas is chlorine trifluoride gas, 5. The substrate processing method according to claim 4, wherein the metal constituting the pipe contains chromium.

6. The second step comprises: a step of adsorbing the basic gas onto a wall surface inside the processing vessel, 6. The substrate processing method according to claim 1, wherein the method is performed in a state where the substrate is not stored in the processing vessel.

7. The second step comprises: a step of adsorbing the basic gas into the porous body, 6. The substrate processing method according to claim 1, further comprising the step of supplying the halogen-based gas to the porous body after stopping the supply of the basic gas to the porous body.

8. 8. The substrate processing method according to claim 7, further comprising the step of evacuating the porous body through an exhaust pipe connected to the piping after stopping the supply of the basic gas to the porous body and before performing the step of supplying the halogen-based gas to the porous body.

9. a processing vessel in which the substrate is stored; a processing gas supply unit that supplies a processing gas into the processing vessel to process the substrate; a metal pipe through which a halogen-based gas flows; a halogen-based gas supply unit that supplies the halogen-based gas into the processing chamber through the piping; a porous body provided in a flow path formed by the piping, or a partition member having a plurality of holes that divides the flow path in the flow path direction and connects the upstream side and downstream side of the flow path; a basic gas supply unit that supplies a basic gas containing nitrogen in its molecules to the porous body or mesh through the flow path so as to generate a complex compound together with the metal constituting the pipe; a control unit that outputs a control signal to perform a first step of supplying the halogen-based gas into the processing vessel and a second step, which is performed before the first step, of supplying the basic gas to the porous body or the partition member and causing it to be adsorbed; A substrate processing apparatus comprising:

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