Substrate processing method and substrate processing apparatus

Abstract

To provide a technique provided for removing etching residues of a germanium-containing silicon film to form a desired etching shape.SOLUTION: An etching gas for germanium-containing silicon is supplied to a substrate on which a germanium-containing silicon film and a silicon film are formed, to etch the germanium-containing silicon film, and then a purge gas containing a first process gas containing fluorine and a second process gas containing at least one of ammonia and an amine is supplied to the substrate to purge the etching gas from the substrate and remove the etching residue of the germanium-containing silicon film.SELECTED DRAWING: Figure 5

Description

[Technical field]

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

[0002] In manufacturing a semiconductor device, one of a germanium-containing silicon (SiGe) film and a silicon (Si) film formed on the surface of a semiconductor wafer (hereinafter, referred to as a wafer) serving as a substrate may be selectively etched. For example, Patent Document 1 describes a technique for suppressing damage to Si by reducing the concentration of by-product gases when selectively etching SiGe using a fluorine-containing gas. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 7113711 Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides a technique for removing etch remnants of a germanium-containing silicon film to form a desired etched shape. [Means for solving the problem]

[0005] The present disclosure provides a method for etching a germanium-containing silicon film by supplying an etching gas for germanium-containing silicon to a substrate on which a germanium-containing silicon film and a silicon film are formed, Then, a purge gas containing a first process gas containing fluorine and a second process gas containing at least one of ammonia and an amine is supplied to the substrate to purge the etching gas from the substrate and remove the etching residue of the germanium-containing silicon film. Effect of the Invention

[0006] According to the present disclosure, the etching residue of the germanium-containing silicon film can be removed to form a desired etching shape. [Brief description of the drawings]

[0007] [Figure 1] 1 is a vertical sectional side view showing an example of a structure to which a substrate processing method according to the present disclosure is applied; [Diagram 2] FIG. 2 is a first enlarged longitudinal cross-sectional view of the structure. [Diagram 3] FIG. 4 is a second enlarged longitudinal cross-sectional view of the structure. [Figure 4] FIG. 4 is a third enlarged longitudinal sectional view of the structure. [Diagram 5] 5A to 5C are explanatory views showing an example of a process flow of the substrate processing method. [Figure 6] 1A to 1C are diagrams illustrating the concept of tuning process conditions when removing etching residuals. [Figure 7] FIG. 2 is a plan view showing an example of a substrate processing system for carrying out the substrate processing method. [Figure 8] 2 is a vertical sectional side view showing an example of a processing module provided in the substrate processing system; FIG. [Figure 9] 11 is an enlarged photograph showing experimental results according to an example and a comparative example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] <Examples of Structures Formed by Substrate Processing According to the Present Disclosure> First, an example of a structure 71 formed on a wafer W by the substrate processing method of the present disclosure will be described with reference to Fig. 1. Fig. 1 is a vertical cross-sectional side view of the structure 71. A multilayer film is formed on the wafer W, in which SiGe films 75 and Si films 74 are alternately stacked in multiple layers. In this multilayer film, each SiGe film 75 has a structure in which a Si film 74 is disposed so as to be sandwiched from the upper and lower sides.

[0009] An opening 72 is formed in this multilayer film in the vertical direction (a direction intersecting with the multiple SiGe films 75 and the Si film 74). As shown in the enlarged vertical cross-sectional view of Fig. 2, the multilayer film exposes the side end faces of the SiGe film 75 and the Si film 74 toward the opening 72. When an etching gas for etching SiGe is supplied through this opening, etching removal proceeds from the side end face of the SiGe film 75, and a horizontal hole is formed along the plate surface of the wafer W (Fig. 3).

[0010] In this manner, partial regions of the plurality of SiGe films 75 exposing their side end faces toward the opening 72 are etched away. As a result, as shown in FIG. 1, a plurality of recesses 73 can be formed, which open toward the opening 72 and are arranged at different height positions in the vertical direction.

[0011] 3, as viewed from the opening of recess 73, the side walls (upper and lower wall portions in the case of a horizontal hole) along the length of recess 73 where etching proceeds are formed of a Si film 74. The inner wall of recess 73, which corresponds to the position where etching is stopped, is formed of a SiGe film 75.

[0012] 1, it is preferable that the tip of each recess 73 has a rectangular shape in view of requirements for subsequent processing of the wafer W. However, it has been found that the tip of the recess 73 formed by the above-mentioned method may end up having a rounded shape (FIG. 3).

[0013] The following mechanism is considered as the reason why the tip of the recess 73 becomes rounded. In the multilayer film forming the structure 71 of FIG. 1, after a plurality of Si films 74 and SiGe films 75 are alternately stacked, an annealing process is sometimes performed to heat the wafer W. In the multilayer film that has been annealed, it is considered that Si atoms diffuse from the Si film 74 toward the SiGe film 75, and a mixed layer 751 with a high concentration of Si atoms is formed near the interface between the SiGe film 75 and the Si film 74 (FIG. 2). Note that the mixed layer 751 is not limited to being formed by the annealing process of the wafer W, and may be formed by natural diffusion of Si atoms.

[0014] For example, the SiGe film 75 in this example is formed so that the concentration of Ge atoms is in the range of 10 to 30 atm%, for example, 25 atm% (in this case, the concentration of Si atoms is about 75 atm%). On the other hand, in the mixed layer 751, the concentration of Ge atoms decreases to about 5 to 10 atm%. That is, the mixed layer 751 is a region where the concentration of Si atoms is increased to about 90 to 95 atm%.

[0015] Here, in the etching process for forming the recess 73, an etching gas for etching the SiGe film 75 is selected that is suitable for etching and removing the SiGe film 75 having the above-mentioned component ratio (Si:Ge=75:25). However, the etching gas selected for the purpose of etching and removing the SiGe film 75 may have a slow etching rate in the mixed layer 751 having a high concentration of Si atoms.

[0016] In this case, when compared along the thickness direction of the SiGe film 75, the etching rate is high in the central region where the concentration of Si atoms is low, while the etching rate is low in the mixed layer 751 where the concentration of Si atoms is high. As a result of the difference in etching rate occurring depending on the position within the SiGe film 75, it is believed that the phenomenon occurs in which the tip of the recess 73 formed by the etching process is rounded as shown in Figure 3. The SiGe (shown surrounded by a dashed line in Figure 3) remaining at the boundary between the side wall and the back wall of the recess 73 due to the relatively low etching rate corresponds to the etching remaining portion 752 of the present disclosure.

[0017] If the etching residue 752 is formed due to a high concentration of Si atoms, it would seem that a separate process of etching and removing the etching residue 752 should be performed using an etching gas suitable for the composition of the mixed layer 751. However, as shown in FIG. 3, the etching residue 752 remains in an extremely small area compared to the entire structure 71. It is not realistic to provide an etching device for forming the recess 73, transport the wafer W to the etching device, and secure time to perform the etching process in order to remove such a small etching residue 752. In addition, an etching gas capable of etching the etching residue 752 having a concentration of Si atoms of about 90 to 95 atm% may even damage the Si film 74 constituting the side wall of the recess 73 depending on the processing conditions.

[0018] Therefore, in the substrate processing method of the present disclosure, after etching the SiGe film 75 to form the recess 73, the etching remaining portion 752 is removed by purging the etching gas. Hereinafter, the substrate processing method of the present disclosure capable of forming the recess 73 having a tip end shape close to a rectangle will be described in detail with reference to Figs. 5 and 6.

[0019] <Substrate processing method> As shown in FIG. 5, an etching gas for SiGe is first supplied to the wafer W on which the multilayer film is formed. As a result, the etching gas enters the opening 72 of the multilayer film shown in FIG. 2, and the etching process of the SiGe film 75 proceeds from the end side exposed toward the opening 72 (process P1: process of etching the SiGe film 75). The etching gas for SiGe may be at least one selected from the group consisting of F2 gas, ClF3 gas, SF6 gas, and IF7 gas. In the following example, a case will be described in which F2 gas and ClF3 gas are used as the etching gas for SiGe, and Ar (argon) gas and N2 (nitrogen) gas are used as the carrier gas.

[0020] The supply flow rates of the gases are, for example, set to 1 to 100 sccm for F2 gas, 0.1 to 2.0 sccm for ClF3 gas, 50 to 200 sccm for N2 gas, and 10 to 100 sccm for Ar gas. For example, the pressure during the etching process is set to a value within a range of 1.3 to 40 Pa (10 to 300 mTorr), and the temperature of the wafer W is set to a value within a range of -50 to 150°C. Furthermore, the etching process time can be set to 50 seconds within a range of 5 to 120 seconds when forming a recess 73 with a depth of about several nm. The etching gas can etch and remove the SiGe film 75 without activation such as plasma generation.

[0021] 3 is formed, while the tip of the recess 73 has a rounded shape. In this disclosure, after etching of the SiGe film 75 is completed, when the etching gas is purged, a purge gas containing a process gas for etching and removing the etching residue 752 is supplied (Process P2 in FIG. 5: a process of purging the etching gas and removing the etching residue 752). For reference, when the etching residue 752 is not etched and removed, a case in which N2 gas and Ar gas are each supplied at 100 sccm can be exemplified as the purge gas.

[0022] The process gases contained in the purge gas are a first process gas containing fluorine and a second process gas containing at least one of ammonia and amine. The first process gas containing fluorine may be at least one selected from the group consisting of F2 gas, ClF3 gas, SF6 gas, and IF7 gas.

[0023] The second process gas may be NH3 gas, amine gas, or a mixture of these. When the second process gas contains an amine gas, the amine may be selected from the group consisting of trimethylamine and butylamine. In the following example, a case will be described in which F2 gas is used as the first processing gas and NH3 gas is used as the second processing gas.

[0024] Here, the mixed gas of F2 gas and NH3 gas can also be used as an etching gas for Si (dotted line in FIG. 6). Therefore, the processing conditions are tuned so that the gas can purge the etching gas used in the etching process of the SiGe film 75 while etching and removing the etching residue 752, which is SiGe containing Ge atoms at a concentration of 5 to 10 atm %, (solid line in FIG. 6).

[0025] As a first tuning, during the process P2 in FIG. 5, the process is performed under a lower pressure condition than during the process P1. This pressure adjustment allows the etching gas supplied during the process P1 to be exhausted from the wafer W, and prevents the supply of a high concentration process gas, thereby suppressing damage to the Si film 74. When purging is performed after the etching process of the wafer W in the process vessel 41 in the process module 4 described later, the set value of the pressure change mechanism of the process vessel 41 is set to a lower pressure. However, since the mixed gas of the above-mentioned F2 gas and NH3 gas is supplied to the process vessel 41 as described above, the actual pressure in the process vessel 41 is within a range of 0.0013 to 66.6 Pa (0.1 to 500 mTorr).

[0026] As the second tuning, the supply ratio of the process gas is adjusted so that the ratio of F2 gas (first process gas) and NH3 gas (second process gas) contained in the purge gas is within the range of 15:1 to 5:1. In the case of the Si etching gas shown by the dashed line in Fig. 6, the supply ratio is adjusted so that the ratio of F2 gas and NH3 gas is about 100:1. Therefore, by reducing the supply ratio of F2 gas, which has a large effect on Si etching, damage to the Si film 74 is suppressed.

[0027] The supply flow rate of each gas may be, for example, 50 to 1000 sccm for F2 gas and 1 to 100 sccm for NH3 gas. The temperature of the wafer W is kept within the range of -50 to 150°C and is not changed, and activation such as plasma generation of the process gas is not performed.

[0028] As a third tuning, the process P2 in Fig. 5 is performed for a shorter time than the process P1. For example, as described above, the etching process of the SiGe film 75 is performed within a range of 5 to 120 seconds, while the purging while supplying the mixed gas of F2 gas and NH3 gas is performed for 10 seconds within a range of 1 to 50 seconds. By completing the purging using the mixed gas of F2 gas and NH3 gas in a shorter time than the etching process of the SiGe film 75, it is possible to remove the minute etching residual portion 752 while suppressing damage to the Si film 74.

[0029] As described above, various tunings are performed when supplying the first process gas (F2 gas in the above example) and the second process gas (NH3 gas) as purge gases. This process removes the etching residue 752 of the mixed layer 751, and makes it possible to form a desired etching shape by making the tip of the recess 73 closer to a rectangle. Here, "making the tip of the recess 73 closer to a rectangle" means that the back wall of the recess 73 is made flatter between the mixed layer 751 and its central region by removing the etching residue 752.

[0030] It is not essential to carry out all of the tuning described above in process P2. As long as the etching residual portion 752 can be removed and the tip of the recess 73 can be made closer to a rectangle while purging the etching gas supplied in process P1, only some of the tuning may be carried out. Also, process P2 may be carried out under conditions other than all of the tuning examples.

[0031] <Substrate processing system> Next, an embodiment of a substrate processing apparatus for carrying out the substrate processing described with reference to Figures 1 to 6 will be described with reference to Figures 7 and 8. The substrate processing system 2 includes a load / unload section 21 for loading and unloading a wafer W, two load lock chambers 31 provided adjacent to the load lock section 21, two heat treatment modules 30 provided adjacent to each of the two load lock chambers 31, and two processing modules 4 provided adjacent to each of the two heat treatment modules 30. The processing module 4 corresponds to the substrate processing apparatus of the present disclosure.

[0032] The load / unload section 21 includes an atmospheric pressure transfer chamber 23 in which a first substrate transfer mechanism 22 is provided and which is kept under atmospheric pressure, and a carrier mounting table 25 provided on the side of the atmospheric pressure transfer chamber 23 and on which a carrier 24 accommodating a wafer W is mounted. Reference numeral 26 in FIG. 7 indicates an aligner chamber adjacent to the atmospheric pressure transfer chamber 23. In the aligner chamber 26, the wafer W is rotated to optically obtain an amount of eccentricity, and the wafer W is aligned with the first substrate transfer mechanism 22. The first substrate transfer mechanism 22 transfers the wafer W between the carrier 24 on the carrier mounting table 25, the aligner chamber 26, and a load lock chamber 31.

[0033] A second substrate transfer mechanism 32 having, for example, an articulated arm structure is provided in each load lock chamber 31, and the second substrate transfer mechanism 32 transfers the wafer W between the load lock chamber 31, the heat treatment module 30, and the treatment module 4. A vacuum atmosphere is maintained inside the treatment vessel constituting the treatment module 4, and the inside of the load lock chamber 31 can be switched between a normal pressure atmosphere and a vacuum atmosphere so that the wafer W can be transferred between the inside of the vacuum atmosphere treatment vessel and the normal pressure transfer chamber 23.

[0034] 7, reference numeral 33 denotes a gate valve that can be opened and closed. The gate valves 33 are provided between the normal pressure transfer chamber 23 and the load lock chamber 31, between the load lock chamber 31 and the heat treatment module 30, and between the heat treatment module 30 and the treatment module 4. The heat treatment module 30 includes the above-mentioned treatment vessel, an exhaust mechanism for exhausting the inside of the treatment vessel to form a vacuum atmosphere, and a stage provided in the treatment vessel and capable of heating the wafer W placed thereon, and is configured to perform a process of heating the wafer W to sublimate a reaction product.

[0035] A process module 4, which is a substrate processing apparatus according to the present disclosure, will be described with reference to the vertical cross-sectional side view of FIG. This process module 4 performs the processes P1 and P2 described above. In FIG. 8, reference numeral 41 denotes a process vessel constituting the process module 4. Reference numeral 42 in the same figure denotes a transfer port for the wafer W that opens in the side wall of the process vessel 41. The transfer port 44 is opened and closed by the gate valve 33 described above. A stage 51 for placing the wafer W thereon is provided in the process vessel 41, and the stage 51 is provided with lift pins (not shown). The wafer W is transferred between the second substrate transfer mechanism 32 and the stage 51 via the lift pins.

[0036] A temperature adjustment unit 52 is embedded in the stage 51, and the wafer W placed on the stage 51 is heated to the temperature described above. This temperature adjustment unit 52 is configured as a flow path that is part of a circulation path through which a temperature adjustment fluid such as water flows, and the temperature of the wafer W is adjusted by heat exchange with the fluid. However, the temperature adjustment unit 52 is not limited to being a flow path for such a fluid, and may be configured, for example, by a heater for performing resistance heating.

[0037] One end of an exhaust pipe 53 opens into the processing vessel 41, and the other end of the exhaust pipe 53 is connected to an exhaust mechanism 55 constituted by, for example, a vacuum pump via a valve 54, which is a pressure changing mechanism. By adjusting the opening of the valve 54, the pressure inside the processing vessel 41 is set to the pressure range described above, and processing is performed.

[0038] A gas shower head 56, which is a processing gas supply mechanism, is provided at the upper portion of the processing vessel 41 so as to face the stage 51. The downstream sides of gas supply paths 611-615 are connected to the gas shower head 56, and the upstream sides of the gas supply paths 611-615 are connected to gas supply sources 631-635 via flow rate adjustment units 62, respectively. Each flow rate adjustment unit 62 includes a valve and a mass flow controller. The gas supplied from the gas supply sources 631-635 is supplied to the downstream side and cut off by opening and closing the valves included in the flow rate adjustment units 62.

[0039] Gas supply sources 631, 632, 633, 634, and 635 supply F2 gas, ClF3 gas, NH3 gas, Ar gas, and N2 gas, respectively. Therefore, the gas shower head 56 can supply these F2 gas, ClF3 gas, NH3 gas, Ar gas, and N2 gas into the processing vessel 41. The Ar gas and N2 gas are supplied as carrier gases into the processing vessel 41 together with the etching gases F2 gas and ClF3 gas. In addition, the F2 gas and NH3 gas are supplied as purge gases into the processing vessel 41.

[0040] As shown in FIG. 7, the substrate processing system 2 includes a control unit 20, which is a computer, and the control unit 20 includes a program, a memory, and a CPU. The program includes commands (each step) for performing the above-mentioned processing of the wafer W and transport of the wafer W. The program is stored in a storage medium, such as a compact disc, a hard disk, a magneto-optical disc, a DVD, a non-volatile memory, and is installed in the control unit 20. The control unit 20 outputs control signals to each part of the substrate processing system 2 according to the program, and controls the operation of each part. Specifically, the operation of the processing module 4, the operation of the heat treatment module 30, the operation of the first substrate transport mechanism 22, the operation of the second substrate transport mechanism 32, and the operation of the aligner chamber 26 are controlled by the control signals. The operation of the processing module 4 includes, for example, the temperature of the fluid supplied to the stage 51, the supply and cut-off of each gas from the gas shower head 56, and the adjustment of the exhaust flow rate by the valve 54.

[0041] <Operation of the substrate processing system> The processing operation of the wafer W in the substrate processing system 2 will be described. As described in FIG. 1, the carrier 24 storing the wafer W on which the multilayer film and the opening 72 are formed is placed on the carrier mounting table 25. Then, the wafer W is transferred in the normal pressure transfer chamber 23 → the aligner chamber 26 → the normal pressure transfer chamber 23 → the load lock chamber 31 in this order, and is transferred to the processing module 4 via the heat treatment module 30. Then, the process P1 of FIG. 5 is performed, and a part of the SiGe film 75 is etched away to form the recess 73. Thereafter, the process P2 of FIG. 5 is performed, and the etching gas for SiGe is purged, and the etching residual portion 752 is removed by a mixed gas of F2 gas and NH3 gas, which is a purge gas. By these processes, the shape of the tip of the recess 73 can be made closer to a rectangle. Thereafter, the wafer W is transferred from the processing module 4 to the heat treatment module 30, the load lock chamber 31, the atmospheric pressure transfer chamber 23, and then returned to the carrier 24.

[0042] <Variations> Here, the subject to which the substrate processing method of the present disclosure is applied is not limited to the wafer W on which the structure 71 shown in FIG. 1 is formed. For example, the substrate processing method of the present disclosure may be applied to a wafer W in which a region in which Si is formed is arranged on either side of a region in which SiGe is formed, as viewed from the top side. In this case, an etching gas for SiGe is supplied to the surface of the wafer W to etch the SiGe, thereby forming a recess extending toward the lower side of the wafer W. Thereafter, a purge gas containing a first process gas containing fluorine and a second process gas containing at least one of ammonia and amine is used to remove the etching residue 752, and a process for making the tip of the recess closer to a rectangle is performed, as in the above-described embodiment.

[0043] In addition, the substrate processing method of the present disclosure is not limited to application when forming a recess. For example, the technology of the present disclosure may be applied when patterning a SiGe film formed on the upper surface of a Si film. In this case, after a patterned resist film or a sacrificial film is formed on the upper surface of the SiGe film, an etching gas for SiGe is supplied to etch the SiGe. Then, the layer of the etching residue remaining on the bottom surface of the patterned SiGe film may be removed using a purge gas containing a first processing gas and a second processing gas.

[0044] Moreover, it is not essential to complete the purge with a purge gas containing a first process gas containing fluorine and a second process gas containing at least one of ammonia and amine. After the above purge is performed, the purge may be continued by supplying another gas (e.g., an inert gas such as N2 gas or Ar gas). Conversely, the etching residue 752 may be removed by using a purge gas containing the first process gas and the second process gas after first performing the purge with an inert gas.

[0045] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The above-described embodiments may be omitted, substituted, or modified in various forms without departing from the scope and spirit of the appended claims. EXAMPLES

[0046] (experiment) After supplying an etching gas for SiGe to a wafer W having a multilayer film of a SiGe film 75 and a Si film 74 formed thereon to form a recess 73, the type of purge gas supplied to the wafer W was changed and the shape of the tip of the recess 73 was confirmed. A. Experimental Conditions (Example) A recess 73 with a depth of 40 nm was formed under the conditions set in the above-mentioned range. Thereafter, the pressure setting was changed to the pressure of the first tuning described above, and purging was performed by supplying F2 gas at a flow rate of 600 sccm and NH3 gas at a flow rate of 40 sccm for 10 seconds. The vertical cross-sectional shape of the wafer W that had been subjected to these processes was observed with an electron microscope. Comparative Example: A process similar to that of the Example was carried out, except that purge gas was supplied at flow rates of N2 gas and Ar gas of 200 sccm.

[0047] B. Experimental Results An enlarged photograph of the example is shown in Fig. 9(a), and an enlarged photograph of the comparative example is shown in Fig. 9(b). According to these photographs, in the example, no influence of the remaining etching residue 752 is observed, and a recess 73 with a rectangular tip is obtained. On the other hand, in the comparative example, the tip of the recess 73 is rounded. This is thought to be due to the influence of the etching residue 752 formed in the mixed layer 751 described with reference to Fig. 3.

[0048] From the above experimental results, it was confirmed that it is possible to make the tip of the recess 73 closer to a rectangle by supplying a purge gas containing F2 gas (first processing gas) and NH3 gas (second processing gas) after etching the SiGe film 75 to form the recess 73. [Explanation of symbols]

[0049] W wafer 71 Structure 73 Recess 74Si film 75 SiGe film 752 Etching Remains

Claims

1. supplying an etching gas for germanium-containing silicon to a substrate on which a germanium-containing silicon film and a silicon film are formed, to etch the germanium-containing silicon film; Then, a purge gas containing a first process gas containing fluorine and a second process gas containing at least one of ammonia and an amine is supplied to the substrate to purge the etching gas from the substrate and remove an etching residue of the germanium-containing silicon film.

2. 2. The substrate processing method according to claim 1, wherein the etching remainder is formed in a region where a silicon concentration is increased due to diffusion of silicon from a silicon film side to the germanium-containing silicon film side, and an etching rate by the etching gas for the germanium-containing silicon is decreased.

3. A multilayer film is formed on the substrate, in which the silicon films are stacked with the germanium-containing silicon film sandwiched therebetween; In the step of etching the germanium-containing silicon film, the germanium-containing silicon film is etched from an end side of the multilayer film to form a recess having a side wall of the silicon film and a back wall of the germanium-containing silicon film; 2. The substrate processing method according to claim 1, wherein in the step of removing the etching residue, the etching residue remaining at a boundary between the side wall and the rear wall of the recess is removed to make a cross-sectional shape of the recess closer to a rectangle.

4. 2. The substrate processing method according to claim 1, wherein the step of removing the etching residue is performed under a pressure condition lower than that of the step of etching the germanium-containing silicon film.

5. 2. The substrate processing method according to claim 1, wherein a ratio of the first process gas to the second process gas contained in the purge gas is within a range of 15:1 to 5:

1.

6. 2. The substrate processing method according to claim 1, wherein the step of removing the etching residue is performed for a time shorter than the step of etching the germanium-containing silicon film.

7. The etching gas for the germanium-containing silicon is F ２ Gas, ClF ３ Gas, SF ６ Gas, IF ７ 10. The method of claim 1, wherein the at least one gas is selected from the group consisting of gases.

8. The first process gas is F ２ Gas, ClF ３ Gas, SF ６ Gas, IF ７ 10. The method of claim 1, wherein the at least one gas is selected from the group consisting of gases.

9. 2. The method of claim 1, wherein when the second process gas contains an amine gas, the amine is selected from the group consisting of trimethylamine and butylamine.

10. a processing vessel for storing a substrate on which a germanium-containing silicon film and a silicon film are formed; an etching gas supply mechanism for supplying an etching gas for germanium-containing silicon into the processing chamber; a purge gas supply mechanism for supplying a purge gas containing a first process gas containing fluorine and a second process gas containing at least one of ammonia and an amine into the process vessel; and a control unit that outputs a control signal to perform a step of supplying the etching gas into the processing vessel to etch the germanium-containing silicon film, and then supplying the purge gas to purge the etching gas from the processing vessel and remove an etching residue of the germanium-containing silicon film.

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