Conditioning method and plasma processing system

Abstract

Disclosed is a conditioning method for a plasma processing chamber in which plasma processing can be performed on a substrate housed therein by supplying a tungsten-containing gas to the inside of the plasma processing chamber, the method including: (A) a step for removing moisture from the inside of the plasma processing chamber by means of a gas that does not contain the tungsten-containing gas; and (B) a step for conditioning the internal environment of the plasma processing chamber by generating plasma while supplying a gas that contains the tungsten-containing gas after the step (A).

Description

Conditioning method and plasma processing system

[0001] The present disclosure relates to a conditioning method and a plasma processing system.

[0002] Patent Document 1 discloses a plasma processing system in which a substrate having a mask film on top of a pattern is placed in a plasma processing chamber, and a tungsten-containing gas is supplied to the plasma processing chamber, thereby forming a protective film on the mask film.

[0003] In this type of plasma processing system, when maintenance is performed to remove films adhering to components inside the plasma processing chamber, for example, the processing vessel is opened to replace consumables or to clean the inside of the processing vessel. When the processing vessel is opened, moisture in the atmosphere is adsorbed to the interior of the processing vessel and the components. In this case, moisture remains inside the processing vessel after maintenance. Therefore, the plasma processing apparatus performs a process to remove moisture adhering to the interior of the processing vessel and the components after maintenance.

[0004] JP 2023-111329 A

[0005] The present disclosure provides a technique that enables stable plasma processing in which a tungsten-containing gas is supplied after maintenance, startup of an apparatus, or the like.

[0006] According to one aspect of the present disclosure, there is provided a method for conditioning a plasma processing chamber capable of supplying a tungsten-containing gas into the chamber and performing plasma processing on a substrate accommodated therein, the method comprising: (A) removing moisture from inside the plasma processing chamber with a gas that does not contain the tungsten-containing gas; and (B) after the step (A), adjusting the internal environment of the plasma processing chamber by generating plasma while supplying a gas that contains the tungsten-containing gas.

[0007] According to one aspect, after maintenance, startup of the apparatus, or the like, plasma processing in which a tungsten-containing gas is supplied can be stably performed.

[0008] FIG. 1 is a diagram illustrating a schematic view of a plasma processing system according to an embodiment. FIG. 2 is a schematic view illustrating an example of a reaction of WF gas with a component having moisture attached thereto in a plasma processing chamber. FIG. 3 is a flowchart illustrating a processing flow of a conditioning method according to an embodiment. FIG. 4A is a table illustrating processing conditions for a moisture removal process. FIG. 4B is a table illustrating the relationship between the number of cycles of a dry cleaning process and the emission intensity of hydrogen remaining in a plasma processing chamber. FIG. 5A is a table illustrating processing conditions for a seasoning process. FIG. 5B is a table illustrating the relationship between the number of cycles of a seasoning process and the etching rate of a silicon oxide film performed in a plasma processing chamber 10. FIG. 6 is a graph comparing the flow rate of WF gas when a flow rate calibration process is performed and when a flow rate calibration process is not performed. FIG. 7 is a timing chart of a conditioning method according to an embodiment.

[0009] 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.

[0010] 1 is a diagram schematically illustrating a plasma processing system according to an embodiment of the present invention. First, an example of the configuration of the plasma processing system will be described with reference to FIG.

[0011] The plasma processing system includes a capacitively coupled plasma processing apparatus 1 and a controller 2. The capacitively coupled plasma processing apparatus 1 includes a plasma processing chamber 10, a gas supply 20, a power supply 30, and an exhaust system 40. The plasma processing apparatus 1 also includes a substrate support 11 and a gas inlet. The gas inlet is configured to introduce at least one process gas into the plasma processing chamber 10. The gas inlet includes a showerhead 13. The substrate support 11 is disposed within the plasma processing chamber 10. The showerhead 13 is disposed above the substrate support 11. In one embodiment, the showerhead 13 forms at least a portion of the ceiling of the plasma processing chamber 10. The plasma processing chamber 10 has a plasma processing space 10s defined by the showerhead 13, a sidewall 10a of the plasma processing chamber 10, and the substrate support 11. The plasma processing chamber 10 has at least one gas inlet for supplying at least one processing gas to the plasma processing space 10s and at least one gas outlet for exhausting gas from the plasma processing space 10s. The sidewall 10a is grounded. The showerhead 13 and the substrate support 11 are electrically insulated from the plasma processing chamber 10 housing.

[0012] The substrate support 11 includes a main body 111 and a ring assembly 112. The main body 111 has a central region (substrate support surface) 111a for supporting a substrate (wafer) W and an annular region (ring support surface) 111b for supporting the ring assembly 112. The annular region 111b of the main body 111 surrounds the central region 111a of the main body 111 in a plan view. The substrate W is disposed on the central region 111a of the main body 111, and the ring assembly 112 is disposed on the annular region 111b of the main body 111 so as to surround the substrate W on the central region 111a of the main body 111. In one embodiment, the main body 111 includes a base and an electrostatic chuck. The base includes a conductive member. The conductive member of the base functions as a lower electrode. The electrostatic chuck is disposed on the base. The upper surface of the electrostatic chuck has the substrate support surface 111a. The ring assembly 112 includes one or more annular members. At least one of the one or more annular members is an edge ring. Although not shown, the substrate support 11 may also include a temperature control module configured to adjust at least one of the electrostatic chuck, the ring assembly 112, and the substrate to a target temperature. The temperature control module may include a heater, a heat transfer medium, a flow path, or a combination thereof. A heat transfer fluid such as brine or gas flows through the flow path. The substrate support 11 may also include a heat transfer gas supply unit configured to supply a heat transfer gas between the back surface of the substrate W and the substrate support surface 111 a.

[0013] The showerhead 13 is configured to introduce at least one process gas from the gas supply unit 20 into the plasma processing space 10s. The showerhead 13 has at least one gas supply port 13a, at least one gas diffusion chamber 13b, and multiple gas inlets 13c. The process gas supplied to the gas supply port 13a passes through the gas diffusion chamber 13b and is introduced into the plasma processing space 10s from the multiple gas inlets 13c. The showerhead 13 also includes a conductive member. The conductive member of the showerhead 13 functions as an upper electrode. In addition to the showerhead 13, the gas inlet may also include one or more side gas injectors (SGIs) attached to one or more openings formed in the sidewall 10a.

[0014] The gas supply unit 20 may include at least one gas source 21 and at least one flow controller 22. In one embodiment, the gas supply unit 20 is configured to supply at least one process gas from a corresponding gas source 21 to the showerhead 13 via a corresponding flow controller 22. Each flow controller 22 may include, for example, a mass flow controller or a pressure-controlled flow controller. Additionally, the gas supply unit 20 may include one or more flow modulation devices to modulate or pulse the flow rate of the at least one process gas.

[0015] The power supply 30 includes an RF power supply 31 coupled to the plasma processing chamber 10 via at least one impedance matching circuit. The RF power supply 31 is configured to supply at least one RF signal (RF power), such as a source RF signal and a bias RF signal, to the conductive members of the substrate support 11 and / or the conductive members of the showerhead 13. This causes plasma to be formed from at least one process gas supplied to the plasma processing space 10s. Thus, the RF power supply 31 can function as at least a part of a plasma generating unit configured to generate plasma from one or more process gases in the plasma processing chamber 10. Furthermore, supplying a bias RF signal to the conductive members of the substrate support 11 generates a bias potential on the substrate W, thereby attracting ion components in the formed plasma to the substrate W.

[0016] In one embodiment, the RF power supply 31 includes a first RF generator 31a and a second RF generator 31b. The first RF generator 31a is coupled to the conductive members of the substrate support 11 and / or the conductive members of the showerhead 13 via at least one impedance matching circuit and is configured to generate a source RF signal (source RF power) for plasma generation. In one embodiment, the source RF signal has a frequency in the range of 13 MHz to 150 MHz. In one embodiment, the first RF generator 31a may be configured to generate multiple source RF signals having different frequencies. The generated one or more source RF signals are supplied to the conductive members of the substrate support 11 and / or the conductive members of the showerhead 13. The second RF generator 31b is coupled to the conductive members of the substrate support 11 via at least one impedance matching circuit and is configured to generate a bias RF signal (bias RF power). In one embodiment, the bias RF signal has a lower frequency than the source RF signal. In one embodiment, the bias RF signal has a frequency in the range of 400 kHz to 13.56 MHz. In one embodiment, the second RF generator 31b may be configured to generate multiple bias RF signals having different frequencies, and the generated bias RF signals or signals are supplied to the conductive members of the substrate support 11. Also, in various embodiments, at least one of the source RF signal and the bias RF signal may be pulsed.

[0017] The power supply 30 may also include a DC power supply 32 coupled to the plasma processing chamber 10. The DC power supply 32 includes a first DC generator 32a and a second DC generator 32b. In one embodiment, the first DC generator 32a is connected to a conductive member of the substrate support 11 and configured to generate a first DC signal. The generated first bias DC signal is applied to the conductive member of the substrate support 11. In one embodiment, the first DC signal may be applied to another electrode, such as an electrode in an electrostatic chuck. In one embodiment, the second DC generator 32b is connected to a conductive member of the showerhead 13 and configured to generate a second DC signal. The generated second DC signal is applied to the conductive member of the showerhead 13. In various embodiments, at least one of the first and second DC signals may be pulsed. The first and second DC generating units 32a and 32b may be provided in addition to the RF power supply 31, or the first DC generating unit 32a may be provided instead of the second RF generating unit 31b.

[0018] The exhaust system 40 may be connected to, for example, a gas exhaust port 10e provided at the bottom of the plasma processing chamber 10. The exhaust system 40 may include a pressure regulating valve and a vacuum pump. The pressure in the plasma processing space 10s is regulated by the pressure regulating valve. The vacuum pump may include a turbomolecular pump, a dry pump, or a combination thereof.

[0019] The controller 2 processes computer-executable instructions that cause the plasma processing apparatus 1 to perform the various processes described in this disclosure. The controller 2 may be configured to control each element of the plasma processing apparatus 1 to perform the various processes described herein. In one embodiment, part or all of the controller 2 may be included in the plasma processing apparatus 1. The controller 2 may include, for example, a computer 2a. The computer 2a may include, for example, a processing unit (CPU: Central Processing Unit) 2a1, a memory unit 2a2, and a communication interface 2a3. The processing unit 2a1 may be configured to perform various control operations based on programs stored in the memory unit 2a2. The memory unit 2a2 may include a random access memory (RAM), a read-only memory (ROM), a hard disk drive (HDD), a solid state drive (SSD), or a combination thereof. The communication interface 2a3 may communicate with the plasma processing apparatus 1 via a communication line such as a LAN (Local Area Network).

[0020] The control unit 2 controls each component of the plasma processing apparatus 1 to perform plasma processing on the substrate W accommodated in the plasma processing chamber 10. The plasma processing system according to the embodiment performs plasma processing by supplying gas for forming a protective film that protects the mask film on the surface of the substrate W from the gas supply unit 20 into the plasma processing chamber 10, and supplying RF power from the power supply 30 to conductive members (the substrate support unit 11, the shower head 13). As a result, plasma etching is performed on the mask film on the surface of the substrate W while a protective film is formed on the mask film.

[0021] In detail, the gas supply unit 20 supplies tungsten-containing gas, such as tungsten hexafluoride (WF ６ (Hereinafter, tungsten hexafluoride gas will also be referred to simply as WF gas.) The tungsten-containing gas is not limited to WF gas, and may be, for example, tungsten pentachloride (WCl ５ ) gas and tungsten hexachloride (WCl ６The gas supply unit 20 may contain an appropriate additive gas in addition to the WF gas, or may supply the additive gas at a different timing. For example, the other additive gas may be a rare gas such as helium (He) gas or argon (Ar) gas, or oxygen (O ２ ) gas and ozone (O ３ ) gas, or nitrogen (N ２ Examples of suitable inert gases include a tungsten-containing gas and an inert gas such as a tungsten-containing gas. The control unit 2 supplies a tungsten-containing gas as the main gas to the plasma processing space 10s and controls plasma generation based on the plasma processing conditions set in the recipe. This allows plasma etching to be performed while forming a tungsten-containing protective film on the mask film.

[0022] As described above, the plasma processing system according to the embodiment performs plasma processing while supplying a tungsten-containing gas (WF gas). This WF gas has a higher specific gravity and higher viscosity than other gases, and is therefore characterized by its tendency to accumulate in a narrow space and its difficulty in being discharged. Therefore, in plasma processing systems that use a tungsten-containing gas as a processing gas, the plasma processing chamber 10 is opened during maintenance to clean the internal components and / or piping, thereby preventing the accumulation of WF gas. In this case, atmospheric moisture (H O ... ２ O) will be attracted to the component 100 and remain there.

[0023] On the other hand, tungsten-containing gases also have the characteristic of easily reacting with moisture. Figure 2 is a schematic diagram showing an example of the reaction of WF gas with a component 100 to which moisture has adhered in a plasma processing chamber 10. WF gas reacts with moisture in the manner shown in the following chemical reaction formulas (1) and (2).

[0024] WF ６ +3H ２ O → WOF ４ +2HF...(1) WF ６ +3H ２ O → WO ３ +6HF ... (2)

[0025] That is, if WF gas is supplied in the presence of moisture inside the plasma processing chamber 10, tungsten oxyfluoride (WOF ４ ) and tungsten oxide (WO ３ ) precipitates on the surface of the component 100 in the plasma processing chamber 10. Therefore, the plasma processing system according to the embodiment first removes moisture from the plasma processing chamber 10, and then performs a conditioning method to prepare the internal environment for the plasma processing of the tungsten-containing gas.

[0026] 3 is a flowchart showing a processing flow of the conditioning method according to the embodiment. Under the control of the controller 2, the plasma processing system performs the moisture removal step (step S1), the seasoning step (step S2), and the flow rate calibration step (step S3) shown in FIG. 3 in this order as the conditioning method.

[0027] The moisture removal step of the conditioning method is a step of removing moisture from within the plasma processing chamber 10. In the moisture removal step, for example, with the substrate W placed on the substrate support 11, a dry cleaning gas is supplied by the gas supply unit 20, and RF source power is supplied from the RF power supply 31 to a conductive member to perform plasma processing (dry cleaning processing). This generates plasma in the plasma processing space 10s, removing moisture and appropriate deposits adhering to each component within the plasma processing chamber 10. The deposits include, for example, reaction products generated during substrate processing prior to the dry cleaning step.

[0028] The dry cleaning gas may be selected appropriately depending on the moisture and deposits. However, the dry cleaning gas should not contain a tungsten-containing gas. For example, the dry cleaning gas may be tetrafluoromethane (CF ４ ) Gas, O ２ Gases, etc. ４ The gas is a CF-containing gas in which carbon (C) and fluorine (F) are bonded, and can remove moisture and deposits by reacting with them. ２Gases can also remove moisture by reacting with it.

[0029] 4A is a table illustrating processing conditions for the moisture removal step. In the moisture removal step, for example, the three steps shown in the table of FIG. 4A are executed in order from the top to the bottom. Specifically, in the first step, the pressure inside the plasma processing chamber 10 is set to 100 mT. Furthermore, the HF power having a frequency of 3 MHz to 150 MHz supplied from the RF power source 31 is set to 600 W, and the LF power having a frequency of 400 kHz to 13.56 MHz supplied from the RF power source 31 is set to 300 W. The main gas supplied in the first step is O ２ The gas is used, and its flow rate is set to 500 sccm. Furthermore, the temperature (chiller temperature) of the heat transfer fluid supplied to the flow path of the temperature control module is set to 90° C. The time for performing this first step is set to 120 seconds.

[0030] In the moisture removal process, the second step is carried out following the first step. In the second step, the pressure in the plasma processing chamber 10 is set to 100 mT, and the chiller temperature is set to 90° C. The HF power is set to 700 W, and the LF power is set to 60 W. The main gas supplied in the second step is CF ４ The gas is set to a flow rate of 250 sccm, and the time for performing this second step is set to 120 seconds.

[0031] Furthermore, in the moisture removal process, the third step is performed following the second step. In the third step, the pressure in the plasma processing chamber 10 is set to 200 mT, and the chiller temperature is set to 90° C. The HF power is set to 700 W, and the LF power is set to 250 W. The gas supplied to the main in the second step is O ２ The gas is set to a flow rate of 500 sccm, and the time for performing this third step is set to 30 seconds.

[0032] In the moisture removal step, the above-described first to third steps of dry cleaning are performed with the substrate W for dry cleaning processing accommodated in the plasma processing chamber 10, thereby removing moisture from within the plasma processing chamber 10. The substrate W for dry cleaning processing may be a dummy substrate, or may be the same substrate W as that for actual plasma processing.

[0033] However, performing only one cycle of the dry cleaning treatments from the first step to the third step is not enough to sufficiently remove moisture from inside the plasma processing chamber 10. Therefore, in the moisture removal step, the cycle of the dry cleaning treatments (from the first step to the third step) is repeated multiple times to sufficiently remove moisture from inside the plasma processing chamber 10.

[0034] 4B is a table showing the relationship between the number of dry cleaning cycles and the hydrogen emission intensity remaining in the plasma processing chamber 10. The hydrogen emission intensity is an index that correlates with the amount of hydrogen (in other words, the amount of moisture) in the plasma processing chamber 10. If the hydrogen emission intensity is high, it can be said that there is a lot of moisture in the plasma processing chamber 10, and if the hydrogen emission intensity is low, it can be said that there is almost no moisture in the plasma processing chamber 10.

[0035] As shown in FIG. 4B , when the number of dry cleaning cycles is small, the hydrogen emission intensity is high. As the number of dry cleaning cycles increases to 10 and 20, the hydrogen emission intensity gradually decreases. After the number of dry cleaning cycles reaches 30, the hydrogen emission intensity remains roughly constant. In this case, almost no moisture remains in the plasma processing chamber 10, and it can be said that the moisture has been successfully removed. Note that in FIG. 4B , the dry cleaning cycles are performed up to 50 times, taking into consideration a margin for more reliable moisture removal and improved throughput before the plasma processing apparatus 1 begins operation, and the hydrogen emission intensity is measured. Based on the above, it is preferable to set the number of dry cleaning cycles in the moisture removal step in the range of 30 to 50. In this embodiment, the number of cycles is set to 50.

[0036] In the moisture removal step, the plasma processing system may perform a waferless dry cleaning process in which a dry cleaning process is performed without placing a substrate W in the plasma processing chamber 10. For example, the moisture removal step may incorporate a waferless dry cleaning process between cycles of a dry cleaning process in which a substrate W is placed in the plasma processing chamber 10.

[0037] After the moisture removal step, the conditioning method proceeds to a seasoning step under the control of the control unit 2 (step S2 in FIG. 3). The seasoning step of the conditioning method adjusts the internal environment of the plasma processing chamber 10 in order to supply a tungsten-containing gas and perform plasma processing. The internal environment of the plasma processing chamber 10 is adjusted to be optimal for the new processing conditions. As a result, the etching rate of the plasma processing can be stabilized immediately after the start of the plasma processing.

[0038] In this seasoning step, for example, with the substrate W placed on the substrate support 11, a seasoning gas is supplied by the gas supply unit 20 and RF source power is supplied from the RF power supply 31 to the conductive member to prepare the internal environment in the plasma processing chamber 10. In this case, plasma processing may be performed in the plasma processing chamber 10 using the processing conditions (recipe) for the actual substrate processing.

[0039] Therefore, the seasoning gas may be selected from the same type of gas as that supplied during substrate processing, and the plasma processing apparatus 1 supplies a tungsten-containing gas (WF gas) as the main gas during the seasoning process. However, the supply rate of WF gas is preferably greater than the supply rate of WF gas during operation of the plasma processing apparatus 1 (when actually plasma processing a substrate W accommodated in the plasma processing chamber 10). For example, if the supply rate of WF gas during operation of the plasma processing apparatus 1 is 5 sccm, the supply rate during the seasoning process may be 7 sccm to 12 sccm. Alternatively, the seasoning process may be performed by supplying only WF gas and Ar gas, without supplying other additive gases that are added during operation of the plasma processing apparatus 1. By using such a seasoning process, the conditioning method can perform a seasoning process mainly using WF gas, thereby smoothly adjusting the internal environment to accommodate WF gas.

[0040] FIG. 5A is a table illustrating processing conditions for the seasoning process. In the seasoning process, the processing conditions shown in the table of FIG. 5A are used as one cycle of seasoning. Specifically, in the seasoning process, the pressure inside the plasma processing chamber 10 is set to 10 mT. Furthermore, the HF power, which has a frequency of 3 MHz to 150 MHz and is supplied from the RF power source 31, is set to 800 W, and the LF power, which has a frequency of 400 kHz to 13.56 MHz and is supplied from the RF power source 31, is set to 200 W. The main gases supplied in the seasoning process are WF gas and Ar gas, with the flow rates of WF gas set to 7 sccm and Ar gas set to 400 sccm. Furthermore, the temperature (chiller temperature) of the heat transfer fluid supplied to the flow path of the temperature control module is set to 50°C. The duration of the seasoning process is set to 120 seconds.

[0041] This seasoning process adjusts the internal environment of the plasma processing chamber 10 to a state suitable for substrate processing using a tungsten-containing gas. However, performing only one cycle of the seasoning process does not sufficiently adjust the internal environment of the plasma processing chamber 10. For this reason, the seasoning process also adjusts the internal environment of the plasma processing chamber 10 by repeating the seasoning process cycle multiple times.

[0042] 5B is a table showing the relationship between the number of seasoning cycles and the etching rate of the silicon oxide film performed in the plasma processing chamber 10. The etching rate of the silicon oxide film is an index that correlates with the internal environment of the plasma processing chamber 10. If the etching rate of the silicon oxide film is high, it can be said that the internal environment of the plasma processing chamber 10 is unstable, and if the etching rate is stable, it can be said that the internal environment of the plasma processing chamber 10 is stable.

[0043] As shown in FIG. 5B, when the number of seasoning cycles is small, the etching rate of the silicon oxide film is high. As the number of seasoning cycles increases to 10 and 20, the etching rate gradually decreases. After the number of seasoning cycles reaches 30, the etching rate remains roughly constant. In this case, it can be considered that the internal environment of the plasma processing chamber 10 is properly adjusted for plasma processing using WF gas. Note that in FIG. 4B, the etching rate of the silicon oxide film is measured after 60 seasoning cycles, taking into consideration a margin for reliable adjustment of the internal environment and improved throughput before the start of operation of the plasma processing apparatus 1. Based on the above, it is preferable to set the number of seasoning cycles in the seasoning step to a range of 30 to 60. In this embodiment, the number of cycles is set to 50.

[0044] The plasma processing system may also incorporate a dry cleaning process (including a waferless dry cleaning process) at an appropriate timing, such as between seasoning process cycles. This makes it possible to remove deposits that have formed during multiple seasoning processes, thereby preventing deposits from remaining in the plasma processing chamber 10.

[0045] After the above-described seasoning step, the conditioning method proceeds to a flow rate calibration step (step S3 in FIG. 3) under the control of the control unit 2. The flow rate calibration step of the conditioning method is a step of calibrating the flow rate controller 22 for adjusting the flow rate of the WF gas supplied into the plasma processing chamber 10.

[0046] For example, in the flow rate calibration step, the plasma processing apparatus 1 causes WF gas to flow from the gas source 21 of the gas supply unit 20, adjusts the WF gas to a target flow rate commanded by the control unit 2 in the flow rate controller 22, and supplies the WF gas into the plasma processing chamber 10. The plasma processing apparatus 1 then detects the flow rate of the WF gas in the plasma processing chamber 10 or the flow rate of the WF gas in the exhaust gas, calculates the difference between the actual flow rate based on the detection information and the target flow rate, and calibrates the flow rate controller 22.

[0047] FIG. 6 is a graph comparing the flow rate of WF gas when the flow rate calibration process was performed and when the flow rate calibration process was not performed. The two bar graphs on the left side of FIG. 6 represent the gas flow rate and error rate when the flow rate of WF gas was adjusted after only the moisture removal process was performed without the flow rate calibration process. The two bar graphs in the middle of FIG. 6 represent the gas flow rate and error rate when the flow rate of WF gas was adjusted after the moisture removal process and seasoning process was performed without the flow rate calibration process. The two bar graphs on the right side of FIG. 6 represent the gas flow rate and error rate when the flow rate of WF gas was adjusted after the moisture removal process and seasoning process was performed with the flow rate calibration process. Each of the two bar graphs represents measurements taken multiple times (twice) to confirm the reproducibility of the experiment.

[0048] When only the moisture removal process was performed, the WF gas flow rate was approximately 4.6 sccm to 4.7 sccm, compared to the target flow rate of 5 sccm, meaning that the WF gas flow rate was insufficient for the target flow rate. On the other hand, when both the moisture removal process and the seasoning process were performed, the WF gas flow rate was 4.9 sccm, which was sufficiently close to the target flow rate (5 sccm) compared to the WF gas flow rate when only the moisture removal process was performed. In other words, it can be said that the conditioning method can adjust the state of the WF gas inside the plasma processing chamber 10 by performing the seasoning process of supplying WF gas.

[0049] Furthermore, when the moisture removal process, seasoning process, and flow rate calibration process were performed, a flow rate approximately equal to the target flow rate (5 sccm) was achieved. That is, in the conditioning method, by performing the flow rate calibration process last, the flow rate of the WF gas from the flow rate controller 22 can be appropriately calibrated. In particular, in the conditioning method, by performing the seasoning process before the flow rate calibration process, the internal environment of the plasma processing chamber 10 is adjusted before the flow rate controller 22 is calibrated. This allows the conditioning method to more accurately calibrate the flow rate controller 22. This allows the plasma processing apparatus 1 to stably supply WF gas at the target flow rate into the plasma processing chamber 10 during actual substrate processing.

[0050] To summarize the conditioning method according to the embodiment described above, the conditioning method is performed when starting up the apparatus or after maintenance in the time sequence shown in Fig. 7. Fig. 7 is a timing chart of the conditioning method according to the embodiment.

[0051] In the plasma processing system, in the conditioning method prior to substrate processing in which a tungsten-containing gas is supplied, the first to third steps of the dry cleaning process in the moisture removal process (step S1: (A)) are repeated multiple times (e.g., 50 cycles). Next, the seasoning process in the seasoning process (step S2: (B)) is repeated multiple times (e.g., 50 cycles). Finally, a flow rate calibration process (step S3: (C)) is performed.

[0052] As a result, the plasma processing system can stably supply WF gas in the actual substrate processing step after performing the conditioning method, thereby improving the accuracy of the plasma processing. In particular, the plasma processing system can accurately adjust the flow rate of WF gas from the start of substrate processing, thereby significantly reducing defects at the start of substrate processing.

[0053] The conditioning method and the plasma processing system are not limited to the above embodiment and may take various modifications. For example, although the flow rate calibration step is performed in the conditioning method, this flow rate calibration step does not have to be performed. By performing the seasoning step as described above, the flow rate of the WF gas supplied into the plasma processing chamber 10 can be made sufficiently close to the target flow rate.

[0054] In the above embodiment, a plasma processing system has been described that performs plasma etching while forming a tungsten protective film on a mask film on the surface of a substrate W. However, the plasma processing system may be configured to perform etching, ashing, or other plasma processing. Furthermore, the conditioning method is not limited to being performed at the start-up or maintenance of the apparatus, and may also be performed when the processing conditions for plasma processing of a substrate W are changed, for example.

[0055] The embodiments disclosed above include, for example, the following aspects. [Supplementary Note 1] A method for conditioning a plasma processing chamber capable of supplying a tungsten-containing gas into the chamber and performing plasma processing on a substrate accommodated therein, the method comprising: (A) removing moisture from inside the plasma processing chamber with a gas that does not contain the tungsten-containing gas; and (B) adjusting the internal environment of the plasma processing chamber after the step (A) by generating plasma while supplying a gas that contains the tungsten-containing gas. [Supplementary Note 2] The conditioning method according to Supplementary Note 1, further comprising: (C) calibrating a flow rate controller that controls the flow rate of the tungsten-containing gas after the step (B). [Supplementary Note 3] The tungsten-containing gas is WF ６ Gas, WCl ５ gas, or WCl ６ The conditioning method according to Supplementary Note 1 or 2, wherein the tungsten-containing gas contains any one of the following gases: [Supplementary Note 4] The conditioning method according to Supplementary Note 3, wherein in the step (B), the supply amount of the tungsten-containing gas is made larger than the supply amount of the tungsten-containing gas when actually plasma-processing a substrate accommodated in the plasma processing chamber; [Supplementary Note 5] In the step (A), the gas not containing the tungsten-containing gas is a CF-containing gas and O ２The conditioning method according to any one of Supplementary Notes 1 to 4, wherein a gas not containing the tungsten-containing gas is supplied to the plasma processing chamber. [Supplementary Note 6] The conditioning method according to any one of Supplementary Notes 1 to 5, wherein in step (A), a process of generating plasma while supplying a gas not containing the tungsten-containing gas to the plasma processing chamber is repeated a plurality of times. [Supplementary Note 7] The conditioning method according to Supplementary Note 6, wherein the number of times of the process in step (A) is set to 30 to 50. [Supplementary Note 8] The conditioning method according to any one of Supplementary Notes 1 to 7, wherein in step (B), a process of generating plasma while supplying a gas containing the tungsten-containing gas to the plasma processing chamber is repeated a plurality of times. [Supplementary Note 9] The conditioning method according to Supplementary Note 8, wherein the number of times of the process in step (B) is set to 30 to 60. [Supplementary Note 10] A plasma processing system including: a plasma processing chamber; a gas supply unit that supplies a tungsten-containing gas into the plasma processing chamber; a power supply that supplies power to the plasma processing chamber to generate plasma; and a controller that controls the gas supply unit and the power supply, wherein the controller controls: (A) a step of removing moisture from inside the plasma processing chamber with a gas that does not contain the tungsten-containing gas; and (B) a step of adjusting an internal environment of the plasma processing chamber by generating plasma while supplying a gas that contains the tungsten-containing gas after the step (A).

[0056] The conditioning method and plasma processing system according to the disclosed embodiments are illustrative in all respects and not restrictive. The embodiments may be modified and improved in various ways without departing from the spirit and scope of the appended claims. The features described in the above embodiments may be configured in other ways and may be combined with each other without any inconsistency.

[0057] The plasma processing apparatus of the present disclosure can be applied to any type of apparatus, including atomic layer deposition (ALD) apparatus, capacitively coupled plasma (CCP), inductively coupled plasma (ICP), radial line slot antenna (RLSA), electron cyclotron resonance plasma (ECR), and helicon wave plasma (HWP).

[0058] This application claims priority from basic application No. 2023-182011, filed on October 23, 2023, with the Japan Patent Office, the entire contents of which are incorporated herein by reference.

[0059] REFERENCE SIGNS LIST 1 plasma processing apparatus 2 control unit 10 plasma processing chamber 20 gas supply unit 30 power supply W substrate

Claims

1. A method for conditioning a plasma processing chamber capable of supplying a tungsten-containing gas therein and performing plasma processing on a substrate placed therein, the method comprising: (A) removing moisture from within the plasma processing chamber with a gas that does not contain the tungsten-containing gas; and (B) after the step (A), adjusting the internal environment of the plasma processing chamber by generating plasma while supplying a gas that contains the tungsten-containing gas.

2. The conditioning method according to claim 1, further comprising the step of: (C) calibrating a flow rate controller that controls the flow rate of the tungsten-containing gas after the step (B).

3. The tungsten-containing gas is WF ６ Gas, WCl ５ Gas, or WCl ６ The conditioning method according to claim 1 or 2, further comprising any one of the following gases:

4. The conditioning method according to claim 3, wherein in step (B), the amount of the tungsten-containing gas supplied is made greater than the amount of the tungsten-containing gas supplied when actually plasma processing a substrate accommodated in the plasma processing chamber.

5. In the step (A), the gas not including the tungsten-containing gas is a CF-containing gas and O ２ The conditioning method according to claim 1 or 2, further comprising supplying a gas.

6. The conditioning method according to claim 1 or 2, wherein in the step (A), a process of generating plasma while supplying a gas not containing the tungsten-containing gas to the plasma processing chamber is repeated a plurality of times.

7. The conditioning method according to claim 6, wherein the number of times of the treatment in the step (A) is set to 30 to 50 times.

8. The conditioning method according to claim 1 or 2, wherein in the step (B), a process of generating plasma while supplying a gas containing the tungsten-containing gas to the plasma processing chamber is repeated a plurality of times.

9. The conditioning method according to claim 8, wherein the number of times of the treatment in step (B) is set to 30 to 60 times.

10. A plasma processing system including: a plasma processing chamber; a gas supply unit that supplies a tungsten-containing gas into the plasma processing chamber; a power supply that supplies power to the plasma processing chamber to generate plasma; and a control unit that controls the gas supply unit and the power supply, wherein the control unit controls: (A) a step of removing moisture from inside the plasma processing chamber by a gas that does not contain the tungsten-containing gas; and (B) after the step (A), a step of adjusting an internal environment of the plasma processing chamber by generating plasma while supplying a gas that contains the tungsten-containing gas.