Gas treatment method and gas treatment device

Abstract

To provide a gas treatment method and a gas treatment device capable of performing uniform treatment on the top and bottom of a recess in the gas treatment of a substrate having a recess with a high aspect ratio.SOLUTION: A gas processing method for gas-processing a substrate having a recess includes placing a substrate having a recess in a chamber, supplying a pressure adjusting gas into the evacuated chamber to raise the pressure in the chamber to adjust the pressure to a predetermined pressure, and causing processing reaction with a processing gas in the chamber to perform gas processing on the side wall of the recess of the substrate, and a processing gas that causes processing reaction is used as at least a portion of the pressure adjusting gas when performing pressure adjustment.SELECTED DRAWING: Figure 11

Description

[Technical Field]

[0001] The present disclosure relates to gas processing methods and gas processing devices. [Background technology]

[0002] In the manufacturing process of semiconductor devices, a technique for chemically treating a semiconductor wafer substrate with a processing gas is known. For example, Patent Documents 1 and 2 disclose a technique for etching a silicon oxide film (SiO2 film) present on a semiconductor wafer using hydrogen fluoride (HF) gas and ammonia (NH3) gas. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-180418 [Patent Document 2] Japanese Patent Application Laid-Open No. 2017-191897 Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides a gas processing method and gas processing apparatus that can uniformly process the top and bottom of a substrate having a high aspect ratio recess. [Means for solving the problem]

[0005] A gas processing method according to one aspect of the present disclosure is a gas processing method for performing gas processing on a substrate having a recess, the method comprising: placing the substrate having the recess in a chamber; supplying a pressure adjusting gas into the chamber, which has been evacuated, to increase the pressure in the chamber and adjust the pressure to a predetermined pressure; and then causing a processing reaction with a processing gas in the chamber to perform gas processing on a sidewall of the recess in the substrate. evacuating the chamber after the gas treatment;and the processing gas causing the processing reaction is used as at least a part of the pressure adjusting gas when the pressure is adjusted. When performing the gas treatment, the temperature of the substrate is set to a temperature at which a reaction product produced in the treatment reaction can be sublimated, and the pressure adjustment, the gas treatment, and the evacuation are repeated multiple times. . [Effects of the Invention]

[0006] According to the present disclosure, there are provided a gas processing method and a gas processing apparatus that can perform gas processing on a substrate having a high aspect ratio recessed portion, uniformly processing the top and bottom of the recessed portion. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a cross-sectional view showing an example of a gas processing apparatus for carrying out a gas processing method according to an embodiment. [Figure 2] 1 is a cross-sectional view showing an example of a structure of a substrate used in an etching method according to an embodiment. [Figure 3] FIG. 3 is a cross-sectional view showing a state in which the substrate of FIG. 2 has been etched. [Figure 4] FIG. 1 is a diagram showing specific gas supply timing and pressure in the prior art. [Figure 5] 5 is a cross-sectional view showing an etching state when the process shown in FIG. 4 is applied to a substrate having a recess with a large aspect ratio. FIG. [Figure 6] 3A and 3B are diagrams illustrating gas supply to recesses in a pressure adjusting step and an etching step when a conventional technique is applied to a substrate having the structure shown in FIG. 2. [Figure 7] 3 is a diagram showing the amounts of HF gas at the top and bottom of a recess in an etching step when a conventional technique is applied to a substrate having the structure shown in FIG. 2. FIG. [Figure 8] FIG. 10 is a diagram showing specific gas supply timings and pressures in an example of an embodiment. [Figure 9] 3A and 3B are diagrams illustrating gas supply to recesses in a pressure adjusting step and an etching step when the embodiment is applied to a substrate having the structure shown in FIG. 2. [Figure 10]3 is a diagram showing the amounts of HF gas at the top and bottom of a recess in an etching step when the embodiment is applied to a substrate having the structure shown in FIG. 2. FIG. [Figure 11] FIG. 4 is a diagram showing an example of a pressure and gas supply sequence in etching according to an embodiment. [Figure 12] FIG. 10 is a diagram showing another example of the pressure and gas supply sequence in etching according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments will be described with reference to the drawings.

[0009] <Gas treatment equipment> 1 is a cross-sectional view showing an example of a gas processing apparatus for carrying out a gas processing method according to one embodiment. The gas processing apparatus shown in FIG. 1 is configured as an etching apparatus for etching silicon oxide-based materials present on, for example, the surface of a substrate. A representative example of silicon oxide-based materials is SiO2, but they may also be SiON, SiOCN, or SiOC.

[0010] 1, the gas processing device 1 includes a sealed chamber 10, and a mounting table 12 is provided inside the chamber 10 on which a substrate W is placed in a substantially horizontal position. The substrate W may be, for example, a semiconductor wafer such as a Si wafer, but is not limited thereto.

[0011] The gas processing device 1 also includes a gas supply mechanism 13 that supplies processing gas to the chamber 10, and an exhaust mechanism 14 that exhausts the inside of the chamber 10.

[0012] The chamber 10 is composed of a chamber body 21 and a lid 22. The chamber body 21 has a substantially cylindrical sidewall 21a and a bottom 21b, and an opening at the top that is closed by the lid 22, which has a recessed portion therein. The sidewall 21a and the lid 22 are sealed by a sealing member (not shown), ensuring airtightness within the chamber 10.

[0013] A shower head 26, which is a gas introduction member, is fitted inside the lid 22 so as to face the mounting table 12. The shower head 26 has a cylindrical main body 31 having a side wall and an upper wall, and a shower plate 32 provided at the bottom of the main body 31. The outer periphery of the main body 31 and the shower plate 32 are sealed with a seal ring (not shown) to form an airtight structure. In addition, a space 33 for diffusing gas is formed between the center of the main body 31 and the shower plate 32.

[0014] A first gas inlet 34 and a second gas inlet 35 are formed vertically in the ceiling wall of the lid 22, and these first gas inlet 34 and second gas inlet 35 penetrate the upper wall of the shower head 26 and are connected to the space 33. The shower plate 32 is formed with a plurality of gas discharge holes 37 that extend vertically from the space 33 and penetrate therethrough to face the inside of the chamber 10.

[0015] Therefore, in the showerhead 26 , gas is supplied to the space 33 through the first gas inlet hole 34 and the second gas inlet hole 35 , and the gas mixed in the space 33 is discharged through the gas discharge hole 37 .

[0016] A loading / unloading port 41 for loading and unloading the substrate W is provided on the side wall portion 21a of the chamber main body 21, and this loading / unloading port 41 can be opened and closed by a gate valve 42, allowing the substrate W to be transported between other adjacent modules.

[0017] The mounting table 12 has a generally circular shape in a plan view and is fixed to the bottom 21b of the chamber 10. A temperature regulator 45 that adjusts the temperature of the mounting table 12 is provided inside the mounting table 12. The temperature regulator 45 can be configured, for example, with a resistance heater or a temperature-regulating medium flow path through which a temperature-regulating medium (such as water) for temperature regulation circulates. The temperature regulator 45 adjusts the temperature of the mounting table 12 to a desired temperature, thereby controlling the temperature of the substrate W placed on the mounting table 12.

[0018] The gas supply mechanism 13 includes an HF gas supply source 51, an Ar gas supply source 52, an NH 3 gas supply source 53, and an N 2 gas supply source .

[0019] The HF gas supply source 51 supplies HF gas as a fluorine-containing gas. Here, HF gas is exemplified as the fluorine-containing gas, but other fluorine-containing gases such as F2 gas, ClF3 gas, and NF3 gas can also be used.

[0020] The NH gas supply source 53 supplies NH gas as a basic gas. Here, NH gas is exemplified as the basic gas, but other than NH gas, amine gas can also be used as the basic gas. Examples of amine include methylamine, dimethylamine, and trimethylamine.

[0021] The Ar gas supply source 52 and the N2 gas supply source 54 supply N2 gas and Ar gas as inert gases that also function as dilution gas, purge gas, and carrier gas. However, both may be Ar gas or N2 gas. Furthermore, the inert gases are not limited to Ar gas and N2 gas, and other rare gases such as He gas can also be used.

[0022] These gas supply sources 51 to 54 are connected to one end of first to fourth gas supply pipes 61 to 64, respectively. The first gas supply pipe 61, which is connected to the HF gas supply source 51, has the other end connected to the first gas inlet hole 34. The second gas supply pipe 62, which is connected to the Ar gas supply source 52, has the other end connected to the first gas supply pipe 61. The third gas supply pipe 63, which is connected to the NH3 gas supply source 53, has the other end connected to the second gas inlet hole 35. The fourth gas supply pipe 64, which is connected to the N2 gas supply source 54, has the other end connected to the third gas supply pipe 63.

[0023] HF gas, which is a fluorine-containing gas, and NH gas, which is a basic gas, along with Ar gas and N gas, which are inert gases, respectively, reach the shower head 26 via the first gas inlet hole 34 and the second gas inlet hole 35, and are discharged into the chamber 10 from the gas outlet hole 37 of the shower head 26.

[0024] A flow rate control unit 65 that opens and closes the flow paths and controls the flow rates is provided in the first to fourth gas supply pipes 61 to 64. The flow rate control unit 65 is composed of, for example, an on-off valve and a flow rate controller such as a mass flow controller (MFC) or a flow control system (FCS).

[0025] The exhaust mechanism 14 has an exhaust pipe 72 connected to an exhaust port 71 formed in the bottom 21b of the chamber 10, and further has an automatic pressure control valve (APC) 73 for controlling the pressure inside the chamber 10 and a vacuum pump 74 for evacuating the inside of the chamber 10, both of which are provided on the exhaust pipe 72.

[0026] Two capacitance manometers 76a, 76b for high pressure and low pressure are provided on the side wall of the chamber 10 to control the pressure inside the chamber 10. A temperature sensor (not shown) for detecting the temperature of the substrate W is provided near the substrate W placed on the mounting table 12.

[0027] The chamber 10, shower head 26, and mounting table 12 that constitute the gas processing device 1 are made of a metal material such as aluminum. A coating such as an oxide coating may be formed on the surface of these components. For example, in the case of aluminum, an anodized oxide coating (Al2O3) may be used as the coating. A ceramic coating may also be used.

[0028] The gas treatment device 1 further includes a control unit 80. The control unit 80 is a computer The gas processing device 1 is composed of a main control unit equipped with a CPU, an input device, an output device, a display device, and a storage device (storage medium). The main control unit controls the operation of each component of the gas processing device 1. The control of each component by the main control unit is performed based on a control program stored in a storage medium (hard disk, optical disk, semiconductor memory, etc.) built into the storage device. A processing recipe is stored in the storage medium as a control program, and processing by the gas processing device 1 is performed based on the processing recipe.

[0029] <Gas treatment method> Next, an embodiment of a gas processing method performed in the above-described gas processing device 1 will be described. In this embodiment, etching, specifically etching of a film made of a silicon oxide material, is performed as gas processing on a substrate W having a recess with a high aspect ratio.

[0030] The specific details will be explained below. First, a substrate W having a recess with a high aspect ratio is carried into the chamber 10 and placed on the mounting table 12. At this time, the temperature of the mounting table 12 is controlled by the temperature controller 45. Then, as a preparation step, the pressure inside the chamber 10 is increased to about 266.6 Pa (2 Torr) to stabilize the temperature of the substrate W, and then the chamber 10 is evacuated.

[0031] The aspect ratio of the recesses in the substrate W is preferably 25 or greater. Substrates W having recesses with such high aspect ratios can be used, for example, in 3D-NAND nonvolatile semiconductor devices. FIG. 2 is a cross-sectional view showing an example of the structure of such a substrate W. In this example, the substrate W has a lower structure 101 formed on a silicon substrate 100, an ON-ON stacked structure 102 formed thereon, and an upper structure 103 formed thereon. Holes 106 are formed through the upper structure 103, the ON-ON stacked structure 102, and the lower structure 101 in the stacking direction.

[0032] Next, gas is supplied into the evacuated chamber 10 to increase the pressure inside the chamber 10, and the pressure is adjusted to a predetermined set pressure and stabilized at that pressure (pressure adjustment step).

[0033] Next, at that pressure, etching is performed as a gas process using NH3 gas, which is a basic gas, and HF gas, which is a fluorine-containing gas (etching step). In this etching, the silicon oxide material present on the sidewall of the recess is etched. In the example of Figure 2, multiple SiO2 films 111 of the ONON stacked structure 102 present on the sidewall of the recess hole 106 are etched as shown in Figure 3.

[0034] The etching reaction, which is the processing reaction at this time, is a reaction between a fluorine-containing gas, a basic gas, and the SiO2 film 111. In this example, HF gas and NH3 gas react with the SiO2 film 111 to generate ammonium silicofluoride (AFS). This AFS can be sublimated by setting the temperature of the substrate W high.

[0035] After performing such etching processing for a predetermined time, the chamber 10 is evacuated to purge the inside of the chamber 10 (evacuation step), thereby discharging residual gases such as sublimated AFS from the chamber 10.

[0036] This sequence can be performed once to achieve the desired amount of etching, or it can be repeated multiple times to achieve the desired amount of etching. That is, the following sequence is repeated multiple times: pressure adjustment → etching → vacuuming → pressure adjustment → etching → vacuuming → ... This allows for etching with better control.

[0037] Conventionally, the purpose of the pressure adjustment step is to stabilize the processing pressure, so it is common for the target processing reaction not to occur during the pressure adjustment step. For example, in Patent Document 2, when etching an SiO2 film using HF gas and NH3 gas, only Ar gas, N2 gas, and NH3 gas are introduced during the pressure stabilization step, which is the pressure adjustment step, and no etching reaction (processing reaction) occurs. Then, HF gas is introduced for the first time in the substrate processing step to cause the etching reaction.

[0038] Figure 4 shows specific gas supply timing and pressure in the prior art. As shown in Figure 4, in the pressure adjustment step, Ar gas, N2 gas, and NH3 gas are supplied as pressure adjustment gases into the vacuumed chamber to increase the pressure in the chamber and stabilize it at the set pressure. Then, in the etching step, HF gas is supplied into the chamber while maintaining the pressure in the chamber at the set pressure to cause an etching reaction. After a predetermined etching time has elapsed, the supply of Ar gas, N2 gas, NH3 gas, and HF gas is stopped, and the chamber is vacuumed.

[0039] However, when the conventional process shown in Fig. 4 is applied to a substrate having a recess with a large aspect ratio, it has been found that top-bottom loading occurs, in which the amount of etching at the bottom of the recess is smaller than that at the top. Specifically, in the example of the substrate shown in Fig. 2, the amount of etching at the top of the SiO2 film 111 is large and the amount of etching at the bottom of the SiO2 film 111 is small, as shown in Fig. 5.

[0040] This point will be explained below. When Ar gas, N gas, and NH gas are supplied to the chamber 10 as pressure-control gases to prevent an etching reaction from occurring on the substrate W having the structure shown in FIG. 2, these gases are also present in the hole 106, as shown in FIG. 6(a). Therefore, when HF gas is supplied for etching after the pressure control, the diffusion of the HF gas is hindered by the Ar gas, N gas, and NH gas in the hole 106, as shown in FIG. 6(b), making it difficult for the HF gas to reach the bottom of the hole 106. That is, as shown in FIG. 7, the diffusion timing of HF gas, which is part of the etchant, is slower at the bottom than at the top, and the amount of HF gas itself is less at the bottom than at the top. This is thought to be the reason why top-bottom loading occurs in etching.

[0041] Therefore, in this embodiment, in the pressure adjustment step, not only Ar gas, N gas, and NH gas but also HF gas are supplied into the chamber 10 as pressure adjustment gases. That is, both NH gas and HF gas, which are process gases that cause the etching reaction, are supplied as part of the pressure adjustment gas. FIG. 8 is a diagram showing specific gas supply timing and pressure in one example of the embodiment. As shown in FIG. 8, in this example, in the pressure adjustment step, not only Ar gas, N gas, and NH gas but also HF gas are supplied as pressure adjustment gases into the vacuumed chamber to increase the pressure in the chamber and stabilize it at the set pressure. Then, the etching step is performed while maintaining the supply of these gases and maintaining the pressure in the chamber at the set pressure.

[0042] 9(a), HF gas is introduced into the hole 106 together with Ar gas, N2 gas, and NH3 gas, and as shown in Fig. 9(b), the HF gas diffuses to the bottom of the hole 106 without being hindered by the Ar gas, N2 gas, and NH3 gas. That is, as shown in Fig. 10, the arrival timing and amount of HF gas, which is the etchant, are approximately the same at the top and bottom portions, allowing for uniform etching with top-bottom loading suppressed.

[0043] Next, a description will be given of an example of a sequence for performing etching of the embodiment on the substrate W having the structure of Fig. 2. Fig. 11 is a diagram showing an example of a pressure and gas supply sequence for etching of the embodiment.

[0044] With the substrate placed on the mounting table 12, first, Ar gas, N2 gas, NH3 gas, and HF gas are all introduced to increase the pressure inside the chamber 10 and stabilize it at a set temperature (step ST1; pressure adjustment step). Next, while maintaining the flow rates of Ar gas, N2 gas, NH3 gas, and HF gas and the pressure inside the chamber 10, the SiO2 film 111 is etched through the hole 106 (step ST2; etching step). After the etching step is completed, the chamber 10 is evacuated to purge the inside of the chamber 10 (step ST3; evacuation step). Steps ST1 to ST3 are repeated a desired number of times.

[0045] In this embodiment, HF gas is supplied in the pressure adjustment step of step ST1, so etching begins when the pressure in the pressure adjustment step reaches or exceeds the pressure at which the etching reaction described above proceeds. That is, the etching reaction proceeds before the etching step (step ST2) in the recipe is reached. This can be addressed by setting the time of the etching step (step ST2) in advance, taking into account the etching amount in the pressure adjustment step. Also, in the recipe, the pressure adjustment step can be integrated into the etching step.

[0046] In the etching step (step ST2), the substrate temperature is preferably set in the range of 75 to 150° C. This allows the AFS generated in the etching reaction to sublimate. The pressure during etching is preferably in the range of 26.6 to 400 Pa (0.2 to 3.0 Torr).

[0047] The flow rates of Ar gas, N2 gas, NH3 gas, and HF gas are preferably in the ranges of 0 to 200 sccm, 0 to 200 sccm, 200 to 1000 sccm, and 200 to 1000 sccm, respectively.

[0048] The above describes an example in which Ar gas, N2 gas, NH3 gas, and HF gas are all supplied from the beginning in the pressure adjustment step, but preflow (step ST1') may be performed to the extent that it does not affect etching, as shown in Fig. 12. Fig. 12 shows an example in which all gases are preflowed, but some gases (for example, N2 gas and Ar gas, or N2 gas, Ar gas, and NH3 gas) may also be preflowed.

[0049] In the above example, the process is repeated, in which the generated AFS is sublimated at a high processing temperature and the sublimated AFS is then removed by evacuation. However, the process may be performed at a lower temperature of 10 to 75°C, for example, 35°C. In this case, after the process using NH3 gas and HF gas, a heat treatment is performed in a separate chamber to sublimate the AFS. This process is performed once or multiple times.

[0050] In addition, when HF gas is supplied to a substrate W having a recess with a high aspect ratio in the pressure adjustment step as in this embodiment, the HF gas concentration at the bottom of the recess may become higher during etching, resulting in bottom-first etching. In such cases, the etching can be made uniform by adjusting parameters such as pressure.

[0051] <Experimental Example> Next, an experimental example will be described. Here, the SiO2 film was etched using NH3 gas and HF gas as etching gas (etchant) on the substrate with the structure of Figure 2 by the apparatus of Figure 1. The etching conditions were a substrate temperature of 80 to 100°C, pressure The pressure was 53.3 to 106.6 Pa (0.4 to 0.8 Torr), the NH3 gas flow rate was 250 to 800 sccm, the HF gas flow rate was 250 to 800 sccm, the Ar gas flow rate was 50 to 150 sccm, and the N2 gas flow rate was 50 to 150 sccm.

[0052] Under the above conditions, etching was performed using a conventional sequence (Sequence A) in which HF gas was not supplied during the pressure adjustment step, and a sequence (Sequence B) according to the embodiment in which HF gas was supplied during the pressure adjustment step. In Sequence A, the etching time was 3 seconds, the evacuation time was 60 seconds, and nine cycles of pressure adjustment, etching, and evacuation were performed. In Sequence B, the etching time was 0.5 seconds, the evacuation time was 60 seconds, and six cycles of pressure adjustment, etching, and evacuation were performed. After etching, the etching amount and the loading value, expressed as the minimum etching amount (Min) / maximum etching amount (Max) in the hole × 100, were calculated. Sequence A resulted in an etching amount of 12.6 nm, with a top-first loading value of 61.3%. In contrast, Sequence B resulted in an etching amount of 9.2 nm, with a top-first loading value of 87.9%, confirming that the use of the method according to the embodiment improves top-bottom loading.

[0053] <Other applications> Although the embodiments have been described above, the disclosed embodiments should be considered to be illustrative and not restrictive in all respects. The above embodiments may be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended claims.

[0054] For example, in the above embodiment, an example was shown in which silicon oxide-based materials were etched using NH3 gas and HF gas, but the present invention is not limited to this and can be similarly applied to etching with other gases.

[0055] In addition, although an example has been shown in which NH3 gas and HF gas, which are process gases that cause an etching reaction as a process reaction, and N2 gas and Ar gas, which are inert gases, are used as part of the pressure adjusting gas, the pressure adjusting gas may be only the process gas that causes the process reaction. In other words, it is sufficient to use the process gas that causes the process reaction as at least part of the pressure adjusting gas.

[0056] Furthermore, in the above embodiment, the substrate has an ONON laminated structure formed by alternately stacking multiple SiO2 films and SiN films, and has holes as recesses in the stacking direction, but the present invention is not limited to this. For example, the substrate may have a high aspect ratio recess with a film to be etched uniformly formed on the side surface.

[0057] Furthermore, the gas processing is not limited to etching, and may be other gas processing such as CVD film formation. In the case of other gas processing, the top-bottom loading of the processing can be suppressed by supplying a processing gas that causes a processing reaction to a substrate having a high aspect ratio recess from the pressure adjustment step.

[0058] Furthermore, in the above embodiment, a semiconductor wafer is used as an example of the substrate, but the substrate is not limited to a semiconductor wafer and may be other substrates such as an FPD (flat panel display) substrate, typified by an LCD (liquid crystal display) substrate, or a ceramic substrate. [Explanation of symbols]

[0059] 1. Gas treatment equipment 10; Chamber 12;Placement table 13. Gas supply mechanism 14;Exhaust mechanism 26. Shower head 45;Temperature controller 51;HF gas supply source 53;NH3 gas source 80;Control unit 100: Silicon substrate 102;ONON laminated section 106; Hole (recess) 111;SiO2 film W; substrate

Claims

1. A gas processing method for performing gas processing on a substrate having a recess, comprising: placing a substrate having a recess in a chamber; supplying a pressure adjusting gas into the evacuated chamber to increase the pressure in the chamber and adjust the pressure to a predetermined pressure; Next, a gas processing is performed on the sidewall of the recess of the substrate by causing a processing reaction with a processing gas in the chamber. evacuating the chamber after the gas treatment; and the process gas causing the process reaction is used as at least a part of the pressure adjusting gas when the pressure is adjusted; When performing the gas treatment, the temperature of the substrate is set to a temperature at which a reaction product generated by the treatment reaction can be sublimated; The gas treatment method, wherein the steps of adjusting the pressure, performing the gas treatment, and evacuation are repeated multiple times.

2. The gas processing method according to claim 1 , wherein the recess of the substrate has an aspect ratio of 25 or more.

3. 3. The gas processing method according to claim 1, wherein the gas processing is etching.

4. 4. The gas processing method of claim 3, wherein the processing gas is a basic gas and a fluorine-containing gas, and etches silicon oxide-based materials present on sidewalls of recesses in the substrate.

5. The substrate is made of the silicon oxide-based material SiO ２ a laminated structure formed by alternately laminating a plurality of SiO 2 films and SiN films, and a hole as the recess formed in the lamination direction of the laminated structure, and the SiO 2 films present on the sidewall of the hole ２ The gas processing method of claim 4, wherein a film is etched.

6. 6. The gas processing method according to claim 4, wherein the pressure adjusting gas used when adjusting the pressure contains an inert gas in addition to the basic gas and fluorine-containing gas used as the processing gas.

7. 7. The gas processing method according to claim 6, wherein the basic gas, the fluorine-containing gas, and the inert gas as the processing gas are supplied when the pressure adjustment is performed, and are continuously supplied when the gas processing is performed.

8. The basic gas is NH ３ 8. The gas processing method according to claim 4, wherein the fluorine-containing gas is a HF gas.

9. A gas processing apparatus for performing gas processing on a substrate having a recess, comprising: a chamber for accommodating a substrate having a recess; a mounting table on which the substrate is placed within the chamber; a gas supply unit that supplies a gas into the chamber; an exhaust unit that exhausts the inside of the chamber; A control unit; Equipped with The control unit placing the substrate in the chamber; supplying a pressure adjusting gas into the evacuated chamber to increase the pressure in the chamber and adjust the pressure to a predetermined pressure; Next, a gas processing is performed on the sidewall of the recess of the substrate by causing a processing reaction with a processing gas in the chamber. evacuating the chamber after the gas treatment; Execute the process gas causing the process reaction is used as at least a part of the pressure adjusting gas when the pressure is adjusted; When performing the gas treatment, the temperature of the substrate is set to a temperature at which a reaction product generated by the treatment reaction can be sublimated; The gas treatment device is controlled so that the pressure adjustment, the gas treatment, and the evacuation are repeated multiple times.

10. The gas processing apparatus of claim 9 , wherein the recess of the substrate has an aspect ratio of 25 or more.

11. 11. The gas processing apparatus according to claim 9, wherein the gas processing is etching.

12. 12. The gas processing apparatus of claim 11, wherein the process gas is a basic gas and a fluorine-containing gas, and etches silicon oxide-based materials present on sidewalls of recesses in the substrate.

13. 13. The gas processing apparatus according to claim 12, wherein the control unit controls the gas supply unit so that the pressure adjusting gas contains an inert gas in addition to the basic gas and fluorine-containing gas as the processing gas when adjusting the pressure.

14. 14. The gas processing apparatus according to claim 13, wherein the control unit controls the gas supply unit to supply the basic gas, the fluorine-containing gas, and the inert gas as the processing gas when the pressure adjustment is performed, and to continue supplying them when the gas processing is performed.

15. The basic gas is NH ３ 15. The gas treatment apparatus according to claim 12, wherein the fluorine-containing gas is a gas, and the fluorine-containing gas is HF gas.

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