Substrate processing method and substrate processing apparatus

Abstract

To provide a substrate processing method and a substrate processing apparatus, in which a silicon-germanium film is formed.SOLUTION: A substrate processing method includes the steps of: preparing a substrate in which a silicon oxide film is formed on a surface of a silicon substrate; supplying a fluorine-containing gas and a basic gas to the substrate having the silicon oxide film and removing the silicon oxide film; supplying a hydrogen gas to the substrate to which a treatment to remove the silicon oxide film has been applied and performing a thermal treatment to the substrate; supplying a mixed gas of a germanium-containing gas diluted with a hydrogen gas to the substrate to which the thermal treatment has been applied to perform pre-cleaning of the substrate; and forming a silicon germanium film by epitaxial growth on the substrate to which the pre-cleaning has been performed.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] Patent Document 1 discloses a method for manufacturing a semiconductor device in which silicon-germanium is vapor-phase grown to epitaxially grow a silicon-germanium single crystal film. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 5-259091 Summary of the Invention [Problem to be solved by the invention]

[0004] In one aspect, the present disclosure provides a substrate processing method and a substrate processing apparatus for forming a silicon germanium film. [Means for solving the problem]

[0005] In order to solve the above problem, according to one aspect, there is provided a substrate processing method including the steps of: preparing a substrate having a silicon oxide film formed on a surface of a silicon substrate; supplying a fluorine-containing gas and a basic gas to the substrate having the silicon oxide film to remove the silicon oxide film; supplying hydrogen gas to the substrate that has been subjected to the treatment to remove the silicon oxide film, thereby performing a heat treatment; supplying a mixed gas of a germanium-containing gas diluted with hydrogen gas to the substrate that has been subjected to the heat treatment, thereby performing a pre-cleaning treatment; and forming an epitaxially grown silicon germanium film on the substrate that has been subjected to the pre-cleaning treatment. [Effects of the Invention]

[0006] According to one aspect, a substrate processing method and a substrate processing apparatus for forming a silicon germanium film can be provided. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a schematic diagram showing an example of the configuration of a substrate processing apparatus according to an embodiment of the present invention; [Figure 2] 1 is a flowchart showing an example of a substrate processing method according to the present embodiment. [Figure 3] FIG. 4 is a sequence diagram showing an example of a substrate processing method according to the present embodiment. [Figure 4] 3A to 3C are examples of schematic cross-sectional views of a substrate W in each step. [Figure 5] 10 is a graph showing an example of measurement results. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals, and redundant explanations may be omitted.

[0009] [Substrate Processing Apparatus] A substrate processing apparatus 100 according to this embodiment will be described with reference to Fig. 1. Fig. 1 is an example of a schematic diagram showing an example of the configuration of the substrate processing apparatus 100 according to this embodiment.

[0010] The substrate processing apparatus 100 includes a cylindrical processing vessel 1 having an open bottom and a ceiling. The entire processing vessel 1 is made of, for example, quartz.

[0011] A wafer boat (substrate holder) 5 carrying a large number of semiconductor wafers (hereinafter referred to as "substrates W") (e.g., 25 to 150) placed in multiple stages as substrates is inserted into the processing vessel 1 from below. In this manner, the processing vessel 1 accommodates the large number of substrates W approximately horizontally with spacing therebetween in the vertical direction. The wafer boat 5 is made of, for example, quartz. The wafer boat 5 has three rods 6 (two are shown in FIG. 1), and the large number of substrates W are supported by grooves (not shown) formed in the rods 6.

[0012] The wafer boat 5 is placed on a table 8 via a heat-retaining cylinder 7 made of quartz. The table 8 is supported on a rotation shaft 10 that passes through a metal (stainless steel) lid 9 that opens and closes the opening at the bottom of the processing vessel 1.

[0013] A magnetic fluid seal 11 is provided at the penetration portion of the rotating shaft 10 to airtightly seal and rotatably support the rotating shaft 10. A seal member 12 is provided between the peripheral portion of the lid 9 and the lower end of the processing vessel 1 to maintain airtightness inside the processing vessel 1.

[0014] The rotation shaft 10 is attached to the tip of an arm 13 supported by a lifting mechanism (not shown), such as a boat elevator, and the wafer boat 5 and the lid 9 are raised and lowered as a unit to be inserted into and removed from the processing vessel 1. Note that the table 8 may be fixed to the lid 9 side so that the substrates W can be processed without rotating the wafer boat 5.

[0015] The substrate processing apparatus 100 also includes a gas supply unit 20 that supplies predetermined gases, such as a processing gas and a purge gas, into the processing chamber 1 .

[0016] The gas supply unit 20 includes gas supply pipes 21 to 23. The gas supply pipes 21 and 22 are made of, for example, quartz, penetrate the sidewall of the manifold 3 inward, bend upward, and extend vertically. The upper ends of the vertical portions of the gas supply pipes 21 and 22 are closed. The vertical portions of the gas supply pipes 21 and 22 have multiple gas holes 21g and 22g formed at predetermined intervals along their vertical lengths corresponding to the wafer support range of the wafer boat 5. Each gas hole 21g and 22g discharges gas horizontally. The gas supply pipes 23 include multiple gas supply pipes 23 (n pipes, n is a natural number of 2 or more; only two are shown in FIG. 1 ) of different heights. The gas supply pipes 23 are made of, for example, quartz, penetrate the sidewall of the processing vessel 1 inward, bend upward, and extend vertically. The upper ends of the vertical portions of the gas supply pipes 23 are open, and discharge the supplied gas. In addition, in the vertical portions of gas supply pipe 23 having different heights, in the portion where there is a difference in height, a plurality of gas holes (not shown) may be formed at predetermined intervals in the side wall of the vertical portion of gas supply pipe 23.

[0017] A vertical portion of the gas supply pipe 21 (the vertical portion where the gas holes 21g are formed) is installed inside the processing chamber 1. A fluorine-containing gas (e.g., HF gas) is supplied to the gas supply pipe 21 from a gas supply source 21a via a gas pipe. The gas pipe is provided with a flow rate controller 21b and an on-off valve 21c. As a result, the fluorine-containing gas from the gas supply source 21a is supplied into the processing chamber 1 via the gas pipe and the gas supply pipe 21.

[0018] A vertical portion of the gas supply pipe 22 (the vertical portion where the gas holes 22g are formed) is installed inside the processing chamber 1. A basic gas (e.g., NH3 gas, or amines such as N(CH3)3 or N(C2H5)3) is supplied to the gas supply pipe 22 from a gas supply source 22a via a gas pipe. A flow rate controller 22b and an on-off valve 22c are installed on the gas pipe. As a result, the basic gas from the gas supply source 22a is supplied into the processing chamber 1 via the gas pipe and the gas supply pipe 22.

[0019] A vertical portion of the gas supply pipe 23 is installed inside the processing chamber 1. A gas supply source 23a1, a gas supply source 23a2, and a gas supply source 23a3 are connected to the gas supply pipe 23 via branched gas pipes.

[0020] The gas supply source 23a1 supplies a silicon (Si)-containing gas to the gas supply pipe 23. The silicon-containing gas may be SiH4 (monosilane) gas, SiH2Cl2 (dichlorosilane), SiH3CH3 (monomethylsilane), or the like. A flow rate controller 23b1 and an on-off valve 23c1 are provided in the branched gas pipe connected to the gas supply source 23a1. The flow rate controller 23b1 and the on-off valve 23c1 are provided corresponding to each of the plurality of gas supply pipes 23. As a result, the silicon-containing gas from the gas supply source 23a1 is supplied into the processing chamber 1 via the gas pipe and the gas supply pipe 23.

[0021] The gas supply source 23a2 supplies a mixed gas of germanium-containing gas (GeH4 gas) diluted with hydrogen gas (H2 gas) to the gas supply pipe 23. The germanium-containing gas may be GeH4 (germane) gas, GeH2 (gerylene) gas, or Ge2H6 (digermane). A flow rate controller 23b2 and an on-off valve 23c2 are provided in the branched gas pipe connected to the gas supply source 23a2. The flow rate controller 23b2 and the on-off valve 23c2 are provided corresponding to each of the plurality of gas supply pipes 23. As a result, the mixed gas of germanium-containing gas from the gas supply source 23a2 is supplied into the processing chamber 1 via the gas pipe and the gas supply pipe 23.

[0022] The gas supply source 23a3 supplies hydrogen (H2) gas to the gas supply pipe 23. A flow rate controller 23b3 and an on-off valve 23c3 are provided in the branched gas pipe connected to the gas supply source 23a3. The flow rate controller 23b3 and the on-off valve 23c3 are provided corresponding to each of the plurality of gas supply pipes 23. As a result, hydrogen gas from the gas supply source 23a1 is supplied into the processing chamber 1 via the gas pipe and the gas supply pipe 23.

[0023] Furthermore, purge gas is supplied to each of the gas supply pipes 21 to 23 from a purge gas supply source (not shown) via gas piping. A flow rate controller (not shown) and an on-off valve (not shown) are provided in the gas piping (not shown). As a result, the purge gas from the purge gas supply source is supplied into the processing chamber 1 via the gas piping and the gas supply pipes 21 to 23. As the purge gas, for example, an inert gas such as nitrogen (N2) gas or argon (Ar) gas can be used.

[0024] An exhaust port 41 for evacuating the inside of the processing vessel 1 is provided in a sidewall portion of the processing vessel 1 opposite to the positions where the gas supply pipes 21-23 are disposed. The exhaust port 41 is formed in the lower part of the sidewall of the processing vessel 1. An exhaust pipe 42 for evacuating the processing vessel 1 is connected to the exhaust port 41. An exhaust device 44 including a pressure control valve 43 for controlling the pressure inside the processing vessel 1 and a vacuum pump is connected to the exhaust pipe 42, and the inside of the processing vessel 1 is evacuated via the exhaust device 44.

[0025] A cylindrical heating mechanism 50 is provided to surround the outer periphery of the processing vessel 1 and heat the processing vessel 1 and the substrate W therein.

[0026] The substrate processing apparatus 100 also includes a control unit 60. The control unit 60 controls the operation of each unit of the substrate processing apparatus 100, for example, opening and closing the on-off valves 21c to 23c3 to supply and stop each gas, controlling the gas flow rate by the flow rate controllers 21b to 23b3, controlling the pressure by the pressure control valve 43, and controlling the exhaust by the exhaust device 44. The control unit 60 also controls the temperature of the substrate W by the heating mechanism 50.

[0027] The control unit 60 may be, for example, a computer. A computer program for controlling the operation of each unit of the substrate processing apparatus 100 is stored in a storage medium. The storage medium may be, for example, a flexible disk, a compact disk, a hard disk, a flash memory, a DVD, or the like.

[0028] [Substrate Processing Method] Next, an example of a substrate processing method using the substrate processing apparatus 100 will be described. FIG. 2 is a flowchart showing an example of the substrate processing method according to this embodiment. FIG. 3 is a sequence diagram showing an example of the substrate processing method according to this embodiment. In FIG. 3, the temperature of the substrate W is shown in the upper part, and the supply timing of various gases is indicated by arrows in the lower part. FIG. 4 is an example of a cross-sectional view of the substrate W in each process. Here, a process of forming a silicon germanium film (SiGe film) 410 and a silicon film (Si film) 420 by epitaxial growth on a substrate W made of single crystal silicon 400 will be described.

[0029] In step S101, a cleaning process is performed on the substrate W in a liquid tank. The cleaning process in the liquid tank includes, for example, substrate cleaning (SPM cleaning) using a cleaning liquid in which sulfuric acid and hydrogen peroxide solution are mixed in a predetermined ratio, substrate cleaning (DHF cleaning) using dilute hydrofluoric acid as a cleaning liquid, and substrate cleaning (APM cleaning) using a cleaning liquid in which ammonia water, hydrogen peroxide solution, and pure water are mixed in a predetermined ratio, thereby cleaning the surface of the substrate W. This removes carbon impurities and watermarks (drying marks) from the substrate W.

[0030] In step S102, the cleaned substrates W are placed on a wafer boat 5, and the wafer boat 5 on which the substrates W are placed is transferred into the processing vessel 1. FIG. 3(a) is an example of a schematic cross-sectional view of the substrates W transferred into the processing vessel 1. As shown in FIG. 3(a), a silicon oxide film 401 (e.g., a native oxide film) is formed on the surface of the substrate W made of single crystal silicon 400.

[0031] In step S103, the substrate W is subjected to a chemical oxide removal (COR) process to remove the silicon oxide film 401.

[0032] 3, the control unit 60 controls the heating mechanism 50 so that the temperature of the substrate W becomes a predetermined first temperature T1. Next, the control unit 60 controls the flow rate controller 21b and the on-off valve 21c to supply a fluorine-containing gas (HF gas) from the gas supply pipe 21 into the processing chamber 1, and controls the flow rate controller 22b and the on-off valve 22c to supply a basic gas (NH gas) from the gas supply pipe 22 into the processing chamber 1. Furthermore, an inert gas (N gas) is supplied from the gas supply pipe 24 into the processing chamber 1. This causes the fluorine-containing gas and the basic gas to react with the silicon oxide film 401 on the surface of the substrate W, forming ammonium silicofluoride [(NH)SiF] on the surface of the substrate W. The first temperature T1 is a temperature (e.g., 65°C) suitable for reacting the fluorine-containing gas, the basic gas, and the silicon oxide film 401 to form ammonium silicofluoride. The basic gas may be an amine such as N(CH3)3 or N(C2H5)3, which forms a silicofluoride compound similar to NH3.

[0033] Next, as shown in FIG. 3, the control unit 60 stops the supply of the fluorine-containing gas (HF gas), basic gas (NH gas), and inert gas (N gas) into the processing chamber 1. Next, the control unit 60 controls the heating mechanism 50 so that the temperature of the substrate W becomes a predetermined second temperature T2. The second temperature T2 is higher than the first temperature T1. The second temperature T2 is a temperature (e.g., 200°C) at which ammonium silicofluoride sublimes. The control unit 60 also controls the flow rate controller 23b3 and the on-off valve 23c3 to supply H gas into the processing chamber 1 through the gas supply pipe 23. This causes the ammonium silicofluoride formed on the surface of the substrate W to sublimate, and the gasified ammonium silicofluoride is exhausted to the outside of the processing chamber 1.

[0034] 3(b) is an example of a schematic cross-sectional view of the substrate W after the processing in step S103. As shown in FIG. 3(b), the silicon oxide film 401 (see FIG. 3(a)) is removed from the surface of the substrate W made of single crystal silicon 400.

[0035] In step S104, a hydrogen bake reduction treatment (heat treatment) is performed.

[0036] The control unit 60 controls the heating mechanism 50 so that the temperature of the substrate W becomes a predetermined third temperature T3. The third temperature T3 is higher than the second temperature T2. The third temperature T3 is preferably, for example, 700°C or higher and 900°C or lower. The third temperature T3 is more preferably 750°C or higher and 850°C or lower. The third temperature T3 is more preferably 750°C or higher and 800°C or lower. The control unit 60 also controls the flow rate controller 23b3 and the on-off valve 23c3 to supply H2 gas into the processing chamber 1 from the gas supply pipe 23. This reduces the surface of the substrate W with the H2 gas, thereby removing halogen (fluorine) from the processing gas (fluorine-containing gas) used in the COR process from the surface of the substrate W. Furthermore, by heating the substrate W to a third temperature T3 higher than the second temperature T2 in step S103, the ammonium silicofluoride formed on the surface of the substrate W is further sublimated and reacted with the remaining silicon oxide film 401, thereby removing the silicon oxide film 401. Note that even if the substrate W is heated to the third temperature T3, residues of the COR process remain on the surface of the substrate W, and it is difficult to completely remove them.

[0037] In step S105, a mixed gas of germanium-containing gas (GeH4 gas) diluted with hydrogen gas (H2 gas) is supplied.

[0038] The control unit 60 controls the heating mechanism 50 so that the temperature of the substrate W becomes a predetermined fourth temperature T4. The fourth temperature T4 is higher than the third temperature T3. The fourth temperature T4 is a temperature (e.g., 450°C or higher and 600°C or lower) at which a SiGe film 410 and a Si film 420, which will be described later, are formed. The control unit 60 also controls the flow rate controller 23b2 and the on-off valve 23c2 to supply a mixed gas of a germanium-containing gas (GeH4 gas) diluted with hydrogen gas (H2 gas) from the gas supply pipe 23 into the processing chamber 1.

[0039] Here, the flow rate ratio of GeH4 gas in the mixed gas of GeH4 gas diluted with H2 is preferably greater than 0% (excluding 0%) and less than 1%, and more preferably greater than 0.01% and less than 1%.

[0040] In a mixed gas of GeH4 gas diluted with H2, GeH4 gas is in chemical equilibrium (GeH4 ⇔ GeH2 + H2), and a mixed gas with a higher H2 ratio allows GeH4 to exist more stably in the mixed gas. Also, as the ratio of GeH4 to GeH2 increases, when GeH4 reacts with the surface of the single-crystal silicon 400, it undergoes a reduction reaction with impurities such as oxygen (O), nitrogen (N), and carbon (C) on the surface of the substrate W, facilitating the removal of impurities.

[0041] In this way, by supplying a mixed gas of GeH4 gas diluted with H2 to the substrate W, residues from the COR process are removed from the substrate W, and impurities (oxygen (O), nitrogen (N), carbon (C), etc.) are removed from the surface of the single crystal silicon 400 of the substrate W. This cleans the surface of the substrate W.

[0042] In step S105, the control unit 60 may control the flow rate controller 23b2 and the on-off valve 23c2 to supply a silicon (Si)-containing gas into the processing chamber 1 from the gas supply pipe 23. That is, in step S105, a mixed gas of a germanium-containing gas (GeH4 gas) diluted with hydrogen gas (H2 gas) and the silicon (Si)-containing gas may be simultaneously supplied. In this case, step S105 and step S106 described later may be regarded as a process for forming one SiGe film 410, and a pre-cleaning process using GeH4 gas diluted with H2 shown in step S105 may be performed at the beginning of the process for forming the SiGe film 410 on the single crystal silicon 400.

[0043] In addition, in step S105, it is not necessary to supply a silicon (Si)-containing gas into the processing vessel 1. That is, in step S105, the supply of a mixed gas of germanium-containing gas (GeH4 gas) diluted with hydrogen gas (H2 gas) may be started, and then in step S106, the supply of silicon (Si)-containing gas may be started.

[0044] After step S105, the hydrogen gas (H 2 gas) may or may not be continuously supplied into the processing chamber 1 from the gas supply source 23a3.

[0045] In step S106, a SiGe film 410 is formed on the substrate W.

[0046] Continuing from step S105, the control unit 60 controls the heating mechanism 50 so that the temperature of the substrate W becomes a predetermined fourth temperature T4. Continuing from step S105, the control unit 60 controls the flow rate controller 23b2 and the on-off valve 23c2 to supply a mixed gas of germanium-containing gas (GeH4 gas) diluted with hydrogen gas (H2 gas) from the gas supply pipe 23 into the processing chamber 1. The flow rate ratio of GeH4 in the mixed gas may remain the same as the flow rate ratio of the mixed gas in step S105. Furthermore, the control unit 60 controls the flow rate controller 23b1 and the on-off valve 23c1 to supply a silicon-containing gas (SiH4 gas) from the gas supply pipe 23 into the processing chamber 1. Furthermore, in step S106, hydrogen gas (H2 gas) from the gas supply source 23a3 may be supplied into the processing chamber 1, or the supply may be stopped.

[0047] As a result, a germanium-containing gas (GeH4 gas) and a silicon-containing gas (SiH4 gas) are supplied onto the single crystal silicon 400, and a SiGe film 410 is formed by epitaxial growth.

[0048] Here, the surface of the substrate W is cleaned by the process shown in step S105, thereby reducing defects in the SiGe film 410 formed by epitaxial growth.

[0049] Furthermore, the mixed gas of GeH4 gas diluted with H2 has a higher ratio of GeH4 to GeH2. This reduces the amount of GeH2 that becomes unstable when the germanium-containing gas reacts with the surface of the single-crystal silicon 400. As a result, the density of Ge clusters, which are the source of defects in the SiGe film 410, decreases, and the number of defects in the SiGe film 410 can be reduced.

[0050] In step S107, a Si film 420 is formed on the substrate W.

[0051] Continuing from steps S105 and S106, the control unit 60 controls the heating mechanism 50 so that the temperature of the substrate W becomes a predetermined fourth temperature T4. Furthermore, the control unit 60 closes the on-off valve 23c2 to stop the supply of a mixed gas of germanium-containing gas (GeH4 gas) diluted with hydrogen gas (H2 gas) into the processing vessel 1. Continuing from step S106, the control unit 60 controls the flow rate controller 23b1 and the on-off valve 23c1 to supply silicon-containing gas (SiH4 gas) into the processing vessel 1 from the gas supply pipe 23. Furthermore, in step S107, the supply of hydrogen gas (H2 gas) from the gas supply source 23a3 into the processing vessel 1 may be continued or the supply may be stopped.

[0052] As a result, a silicon-containing gas (SiH4 gas) is supplied onto the SiGe film 410, and a Si film 420 is formed by epitaxial growth. Figure 3(c) is an example of a schematic cross-sectional view of the substrate W after the processing of step S107. As shown in Figure 3(c), the SiGe film 410 and the Si film 420 are stacked on the substrate W by the processing of steps S106 and S107.

[0053] In step S108, the control unit 60 determines whether the lamination of the SiGe film 410 and the Si film 420 has been repeated a predetermined number of times. If the lamination has not been repeated the predetermined number of times (S108: NO), the process of the control unit 60 returns to step S106, and the lamination of the SiGe film 410 and the Si film 420 is repeated. If the lamination has been repeated the predetermined number of times (S108: YES), the substrate process shown in FIG. 2 is terminated.

[0054] Fig. 3(d) is an example of a schematic cross-sectional view of the substrate W after the substrate processing shown in Fig. 2. As shown in Fig. 3(d), by repeating the processing of steps S106 and S107, SiGe films 410 and Si films 420 are alternately stacked on the substrate W.

[0055] As described above, according to the substrate processing method shown in FIG. 2, defects in the SiGe film 410 formed on the substrate W by epitaxial growth can be reduced.

[0056] Specifically, impurities and the like are cleaned from the surface of the substrate W by substrate cleaning in a liquid bath (SPM cleaning, DHF cleaning, APM cleaning) (step S101), COR treatment (step S103), hydrogen bake reduction treatment (step S104), and pre-cleaning treatment using a mixed gas of GeH4 gas diluted with H2 (step S105). As a result, a SiGe film 410 is formed by epitaxial growth on the surface of the cleaned substrate W, and defects in the SiGe film 410 can be reduced.

[0057] The pre-cleaning process of the substrate processing method according to this embodiment will be described while comparing the substrate processing method according to the reference example with the substrate processing method according to this embodiment.

[0058] In the substrate processing method according to the first reference example, impurities and the like are cleaned from the surface of the substrate W by performing substrate cleaning in a liquid tank (SPM cleaning, DHF cleaning, APM cleaning) (step S101), COR processing (step S103), and hydrogen bake reduction processing (step S104). In this case, the silicon oxide film 401 can be removed by the hydrogen bake reduction processing at 800° C. (step S104). However, residues from the COR processing remain on the surface of the substrate W, which may cause defects when the SiGe film 410 is formed.

[0059] In the substrate processing method according to the second reference example, impurities and the like are cleaned from the surface of the substrate W by substrate cleaning in a liquid tank (SPM cleaning, DHF cleaning, APM cleaning) (step S101) and hydrogen bake reduction treatment (step S104). In this case, the silicon oxide film 401 can be removed by the hydrogen bake reduction treatment at 850° C. (step S104). On the other hand, the substrate processing method according to the second reference example requires a higher bake temperature than the substrate processing method according to the first reference example, which uses COR treatment. Therefore, depending on the type of semiconductor device formed on the substrate W, the method may not be applicable due to temperature restrictions.

[0060] In the substrate processing method according to the third reference example, impurities and the like are cleaned from the surface of the substrate W by substrate cleaning in a liquid tank (SPM cleaning, DHF cleaning, APM cleaning) (step S101) and pre-cleaning processing using a mixed gas of GeH gas diluted with H (step S105). In this case, the silicon oxide film 401 and impurities and the like cannot be removed.

[0061] In contrast, in the substrate processing method according to this embodiment, impurities and the like are cleaned from the surface of the substrate W by substrate cleaning in a liquid tank (SPM cleaning, DHF cleaning, APM cleaning) (step S101), COR processing (step S103), hydrogen bake reduction processing (step S104), and pre-clean processing using a mixed gas of GeH4 gas diluted with H2 (step S105).

[0062] In the substrate processing method according to this embodiment, residues from the COR process can be removed, which means that defects in the SiGe film 410 can be reduced compared to the first and third reference examples.

[0063] Furthermore, in the substrate processing method according to this embodiment, the silicon oxide film 401 can be removed by the hydrogen bake reduction process (step S104) at 800° C. That is, compared to the second reference example, the bake temperature can be lowered, and the applicable range of the process can be expanded.

[0064] Although the substrate processing apparatus 100 has been described with reference to an example in which the gas supply source 23a2 supplies a mixed gas of germanium-containing gas (GeH4 gas) diluted with hydrogen gas (H2 gas), the present invention is not limited to this. The gas supply source 23a2 may supply germanium-containing gas (GeH4 gas). In this configuration, the gas supply unit 20 may mix the germanium-containing gas (GeH4 gas) supplied from the gas supply source 23a2 with hydrogen gas (H2 gas) supplied from the gas supply source 23a3 and supply the mixed gas into the processing chamber 1.

[0065] In the substrate processing method according to the present embodiment shown in FIG. 2, the processes from step S102 to step S108 are described as being performed in a single processing vessel 1. However, this is not limiting. Each process may be performed in a different processing vessel. For example, the substrate processing apparatus may include a first processing vessel for performing the COR process (step S103), a second processing vessel for performing the hydrogen bake reduction process (step S104), a third processing vessel for performing the mixed gas pre-clean process (step S105), the SiGe film formation process (step S106), and the Si film formation process (step S107), and a transfer chamber connected to the first to third processing vessels. The transfer chamber has a vacuum atmosphere or an inert gas atmosphere, and can transfer the substrate W from one processing vessel to another processing vessel without exposing the substrate W to the atmosphere. The vacuum transfer chamber may also include a transfer device for transferring the substrate, and may be configured to transfer the substrate from a wafer boat in one processing vessel to a wafer boat in another processing vessel. The vacuum transfer chamber may also be configured to include a transfer device for transferring a wafer boat on which substrates are placed, and to transfer the wafer boat from one processing vessel to another processing vessel.

[0066] Although the substrate processing apparatus 100 has been described as a batch-type substrate processing apparatus 100 that processes a plurality of substrates W held in a wafer boat 5, the present invention is not limited to this. The substrate processing method shown in FIG. 2 may also be applied to a single-wafer-type substrate processing apparatus.

[0067] Although the SiGe film 410 has been described as being formed by supplying a mixed gas of germanium (Ge)-containing gas diluted with hydrogen gas and a silicon (Si)-containing gas, the present invention is not limited to this. Carbon (C) may be added to the SiGe film 410 by supplying a mixed gas of germanium (Ge)-containing gas diluted with hydrogen gas, a silicon (Si)-containing gas, and a carbon (C)-containing gas. Similarly, carbon (C) may be added to the Si film 420 by supplying a silicon (Si)-containing gas and a carbon (C)-containing gas.

[0068] [Example of measurement results] Next, an example of the measurement results will be described with reference to FIG. 5. FIG. 5 is a graph showing an example of the measurement results. First, multiple substrates W were subjected to substrate cleaning (SPM cleaning, DHF cleaning, APM cleaning) in a liquid bath (step S101). Next, multiple substrates W were placed on a wafer boat 5 and subjected to COR processing (step S103) and hydrogen bake reduction processing (step S104) in a batch-type substrate processing apparatus 100. Next, a 10-nm SiGe film 410 was formed by supplying SiH gas and a mixed gas of GeH gas diluted with H at different flow rates (steps S105 and S106). Next, SiH gas was supplied to form a 50-nm Si film 420 (step S107). Then, the number of defects was counted for the substrates W placed in the lowest slot of the wafer boat 5 and the substrates W placed in the middle slot of the wafer boat 5. 5, the vertical axis represents the average number of defects (Defect#) on the middle and lower substrates W. (a) to (i) represent each run (process).

[0069] In steps S105 and S106, SiH gas (1250 sccm) was supplied from gas supply source 23a1, a mixed gas of GeH gas diluted to 10% with H (630 sccm) was supplied from gas supply source 23a2, and H gas (999 sccm) was supplied from gas supply source 23a3. In step S107, SiH gas (1250 sccm) was supplied from gas supply source 23a1, and H gas (999 sccm) was supplied from gas supply source 23a3.

[0070] In steps S105 and S106, SiH gas (250 sccm) was supplied from gas supply source 23a1, a mixed gas of GeH gas diluted to 1% with H was supplied from gas supply source 23a2 (1260 sccm in (d) and 1640 sccm in (e)), and H gas (999 sccm) was supplied from gas supply source 23a3. In step S107, SiH gas was supplied from gas supply source 23a1, and H gas (999 sccm) was supplied from gas supply source 23a3.

[0071] In steps S105 and S106, SiH gas was supplied from gas supply source 23a1 (100 sccm to 1000 sccm), a mixed gas of GeH gas diluted to 10% with H was supplied from gas supply source 23a2 (10 sccm to 1000 sccm), and the supply of H gas from gas supply source 23a3 was stopped (0 sccm). In step S107, SiH gas was supplied from gas supply source 23a1 (100 sccm to 1000 sccm), and the supply of H gas from gas supply source 23a3 was stopped (0 sccm).

[0072] In addition, in FIG. 5, the average value of the number of defects in (a) to (c) and the average value of the number of defects in (f) to (i) are indicated by dashed lines.

[0073] As shown by comparing (a)-(c) with (f)-(i), the number of defects was reduced in (f)-(i), which used a mixture of GeH4 gas diluted to 1%, compared to (a)-(c).

[0074] Furthermore, as shown by comparing (a)-(c) with (d)-(e), the number of defects was also reduced in (f)-(i), which used a mixture of GeH4 gas diluted to less than 1%, compared to (a)-(c).

[0075] The above describes the film formation method of this embodiment using the substrate processing apparatus 100, but the present disclosure is not limited to the above embodiment, etc., and various modifications and improvements are possible within the scope of the gist of the present disclosure described in the claims. [Explanation of symbols]

[0076] 1. Processing container 5. Wafer boat (substrate holder) 20 Gas supply unit 50 Heating mechanism 60 Control Unit 100 Substrate processing apparatus 400 Monocrystalline silicon 401 Silicon oxide film 410 Silicon germanium film 420 Silicone membrane W substrate

Claims

1. preparing a substrate having a silicon oxide film formed on a surface of a silicon substrate; supplying a fluorine-containing gas and a basic gas to the substrate having the silicon oxide film, thereby removing the silicon oxide film; a step of supplying hydrogen gas to the substrate from which the silicon oxide film has been removed and performing a heat treatment thereon; a step of performing a pre-cleaning process by supplying a mixed gas of germanium-containing gas diluted with hydrogen gas to the substrate that has been subjected to the heat treatment; forming an epitaxially grown silicon germanium film on the substrate that has been subjected to the pre-cleaning treatment; Substrate processing method.

2. the mixed gas has a flow rate ratio of the germanium-containing gas to the mixed gas of 1% or less; The substrate processing method according to claim 1 .

3. The heat treatment is carried out at 800°C or less. The substrate processing method according to claim 1 .

4. The germanium-containing gas is GeH ４ , GeH ２ , Ge ２ H ６ Contains any of the following: The substrate processing method according to claim 1 .

5. The step of preparing the substrate includes wet cleaning the substrate. The substrate processing method according to claim 1 .

6. the fluorine-containing gas is HF; The basic gas is NH ３ or an amine, The substrate processing method according to claim 1 .

7. The method further comprises the step of forming an epitaxially grown silicon film on the substrate on which the silicon germanium film has been formed. The substrate processing method according to claim 1 .

8. A processing vessel; a substrate holder that holds a substrate in the processing chamber; a gas supply unit that supplies a gas into the processing chamber; a heating mechanism for heating the substrate; a control unit, The control unit preparing a substrate having a silicon oxide film formed on a surface of a silicon substrate; supplying a fluorine-containing gas and a basic gas to the substrate having the silicon oxide film, thereby removing the silicon oxide film; a step of supplying hydrogen gas to the substrate from which the silicon oxide film has been removed and performing a heat treatment thereon; a step of performing a pre-cleaning process by supplying a mixed gas of germanium-containing gas diluted with hydrogen gas to the substrate that has been subjected to the heat treatment; forming an epitaxially grown silicon germanium film on the substrate that has been subjected to the pre-cleaning treatment; Substrate processing equipment.

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