Plasma treatment method and plasma treatment device

Abstract

The plasma processing method disclosed in this invention includes step (a), which involves placing a substrate on a substrate support surface of a substrate support portion disposed within a chamber of a plasma processing apparatus. The plasma processing method further includes step (b), which involves etching a film on the substrate using plasma. The plasma processing method further includes step (c), which involves cleaning the chamber using plasma. In steps (b) and (c), a bias voltage comprising a DC voltage pulse and having a pulse waveform is periodically applied to a bias electrode of the substrate support portion. The bias voltage has a bias frequency that is the reciprocal of the duration of the pulse waveform period. The bias frequency in step (c) is higher than the bias frequency in step (b).

Description

Technical Field

[0001] The exemplary embodiments of the present invention relate to a plasma treatment method and a plasma treatment apparatus. Prior Technology

[0002] A plasma processing apparatus is used for etching films on a substrate. During etching of the substrate film in the plasma processing apparatus, byproducts are formed on the surface of the chamber. The chamber is cleaned to remove these byproducts. The cleaning of the chamber is described in Patent Document 1 below. [Previous Technical Documents] [Patent Literature]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-36658 Summary of the Invention

[0004] [The problem the invention aims to solve]

[0005] This invention provides a technique for improving the cleaning and removal performance of substances adhering to the surface of a cavity. [Technical means to solve the problem]

[0006] In one exemplary embodiment, a plasma processing method is provided. The plasma processing method includes step (a), in which a substrate is placed on a substrate support surface of a substrate support portion disposed within a chamber of a plasma processing apparatus. The plasma processing method further includes step (b), in which a film on the substrate is etched within the chamber using plasma generated by a self-etching gas. The plasma processing method further includes step (c), in which a chamber is cleaned within the chamber using plasma generated by a self-cleaning gas. In steps (b) and (c), a bias voltage comprising a DC voltage pulse and having a pulse waveform is periodically applied to a bias electrode of the substrate support portion. The bias voltage has a bias frequency that is the reciprocal of the duration of the waveform period of the pulse waveform. The bias frequency in step (c) is higher than the bias frequency in step (b). [Effects of the Invention]

[0007] According to one exemplary embodiment, the cleaning and removal performance of substances adhering to the surface of the chamber can be improved. Simple Explanation of the Diagram

[0008] Figure 1 is a flowchart of an exemplary embodiment of a plasma processing method. Figure 2 is a diagram illustrating an example of the configuration of a plasma processing system. Figure 3 is a diagram illustrating an example of the configuration of a capacitively coupled plasma processing device. Figure 4 is a timing diagram of an example of a plasma processing apparatus associated with an exemplary embodiment. Figure 5 shows the experimental results. Implementation

[0009] Hereinafter, various exemplary embodiments will be described in detail with reference to the drawings. Furthermore, the same or equivalent parts will be labeled with the same symbols in each drawing.

[0010] Figure 1 is a flowchart of an exemplary embodiment of a plasma treatment method. The plasma treatment method shown in Figure 1 (hereinafter referred to as "Method MT") is performed using a plasma treatment apparatus.

[0011] Figure 2 is a diagram illustrating an example of the configuration of a plasma processing system. In one embodiment, the plasma processing system includes a plasma processing apparatus 1 and a control unit 2. The plasma processing system is an example of a substrate processing system, and the plasma processing apparatus 1 is an example of a substrate processing apparatus. The plasma processing apparatus 1 includes a plasma processing chamber 10, a substrate support 11, and a plasma generation unit 12. The plasma processing chamber 10 has a plasma processing space. Furthermore, the plasma processing chamber 10 has at least one gas supply port for supplying at least one processing gas to the plasma processing space, and at least one gas outlet for discharging gas from the plasma processing space. The gas supply port is connected to the gas supply unit 20, and the gas outlet is connected to the exhaust system 40. The substrate support 11 is disposed within the plasma processing space and has a substrate support surface for supporting a substrate.

[0012] The plasma generation unit 12 is configured to generate plasma from at least one processing gas supplied to the plasma processing space. The plasma formed in the plasma processing space may also be capacitively coupled plasma (CCP), inductively coupled plasma (ICP), electron-cyclotron-resonance plasma (ECR), helicon wave plasma (HWP), or surface wave plasma (SWP), etc.

[0013] The control unit 2 processes commands that can be executed by a computer to cause the plasma processing apparatus 1 to perform the various steps described herein. The control unit 2 may be configured to control various elements of the plasma processing apparatus 1 in a manner that performs the various steps described herein. In one embodiment, part or all of the control unit 2 may also be included in the plasma processing apparatus 1. The control unit 2 may also include a processing unit 2a1, a memory unit 2a2, and a communication interface 2a3. The control unit 2 may, for example, be implemented by a computer 2a. The processing unit 2a1 may be configured to perform various control actions by reading a program from the memory unit 2a2 and executing the read program. The program contains commands that can be executed by a computer to cause the plasma processing apparatus 1 to perform various steps of the control method of the exemplary embodiments described below. The program may be pre-stored in the memory unit 2a2 and may also be retrieved via a media when needed. The retrieved program is stored in the memory unit 2a2 and is read from and executed by the processing unit 2a1. The media can be any memory medium that the computer 2a can read, or it can be a communication line connected to the communication interface 2a3. The processing unit 2a1 can also be a CPU (Central Processing Unit). The memory unit 2a2 can also include RAM (Random Access Memory), ROM (Read Only Memory), HDD (Hard Disk Drive), SSD (Solid State Drive), or a combination thereof. The communication interface 2a3 can also communicate with the plasma processing device 1 via a communication line such as a LAN (Local Area Network).

[0014] The following describes a configuration example of a capacitively coupled plasma treatment apparatus, which is one example of a plasma treatment apparatus 1. Figure 3 is a diagram used to illustrate a configuration example of a capacitively coupled plasma treatment apparatus.

[0015] The capacitively coupled plasma processing apparatus 1 includes a plasma processing chamber 10, a gas supply unit 20, a power supply system 30, and an exhaust system 40. Furthermore, the plasma processing apparatus 1 includes a substrate support unit 11 and a gas inlet unit. The gas inlet unit is configured to introduce at least one processing gas into the plasma processing chamber 10. The gas inlet unit includes a cluster nozzle 13. The substrate support unit 11 is disposed within the plasma processing chamber 10. The cluster nozzle 13 is disposed above the substrate support unit 11. In one embodiment, the cluster nozzle 13 constitutes 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 cluster nozzle 13, the sidewall 10a of the plasma processing chamber 10, and the substrate support unit 11. The plasma processing chamber 10 is grounded. The cluster nozzle 13 and the substrate support unit 11 are electrically insulated from the housing of the plasma processing chamber 10.

[0016] The substrate support portion 11 includes a body portion 111 and a ring assembly 112. The body portion 111 has a central region 111a for supporting the substrate W and an annular region 111b for supporting the ring assembly 112. An example of a wafer-based substrate W. The annular region 111b of the body portion 111 surrounds the central region 111a of the body portion 111 when viewed from above. The substrate W is disposed on the central region 111a of the body portion 111, and the ring assembly 112 is disposed on the annular region 111b of the body portion 111 in a manner that surrounds the substrate W on the central region 111a of the body portion 111. Therefore, the central region 111a is also referred to as the substrate support surface for supporting the substrate W, and the annular region 111b is also referred to as the annular support surface for supporting the ring assembly 112.

[0017] In one embodiment, the body portion 111 includes a base 1110 and an electrostatic chuck 1111. The base 1110 includes a conductive member. The electrostatic chuck 1111 is disposed on the base 1110. The electrostatic chuck 1111 includes a ceramic member 1111a and an electrostatic electrode 1111b disposed within the ceramic member 1111a. The ceramic member 1111a has a central region 111a. In one embodiment, the ceramic member 1111a also has an annular region 111b. Furthermore, other members surrounding the electrostatic chuck 1111, such as an annular electrostatic chuck or an annular insulating member, may also have an annular region 111b. In this case, the ring assembly 112 may be disposed on the annular electrostatic chuck or the annular insulating member, or on both the electrostatic chuck 1111 and the annular insulating member.

[0018] The ring assembly 112 includes one or more annular members. In one embodiment, the one or more annular members include one or more edge rings and at least one cover ring. The edge rings are formed of a conductive or insulating material, and the cover rings are formed of an insulating material.

[0019] Furthermore, the substrate support portion 11 may also include a temperature control module configured to adjust at least one of the electrostatic chuck 1111, the ring assembly 112, and the substrate to a target temperature. The temperature control module may also include a heater, a heat transfer medium, a flow path 1110a, or a combination thereof. A heat transfer fluid, such as brine or gas, flows through the flow path 1110a. In one embodiment, the flow path 1110a is formed within the base 1110, and one or more heaters are disposed within the ceramic component 1111a of the electrostatic chuck 1111. Additionally, the substrate support portion 11 may also include a heat transfer gas supply portion configured to supply heat transfer gas to the gap between the back surface of the substrate W and the central region 111a.

[0020] The cluster injector 13 is configured to introduce at least one processing gas from the gas supply unit 20 into the plasma processing space 10s. The cluster injector 13 has at least one gas supply port 13a, at least one gas diffusion chamber 13b, and a plurality of gas inlets 13c. The processing gas supplied to the gas supply port 13a is introduced into the plasma processing space 10s through the gas diffusion chamber 13b and the plurality of gas inlets 13c. Furthermore, the cluster injector 13 includes at least one upper electrode. Moreover, in addition to the cluster injector 13, the gas inlet unit may also include one or more side gas injectors (SGIs) mounted on one or more openings formed in the sidewall 10a.

[0021] The gas supply unit 20 may also 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 its respective gas source 21 to the cluster nozzle 13 via its respective flow controller 22. Each flow controller 22 may include, for example, a mass flow controller or a pressure-controlled flow controller. Furthermore, the gas supply unit 20 may also include at least one flow modulation element for modulating or pulsed the flow of at least one process gas.

[0022] The exhaust system 40 may be connected, for example, to a gas outlet 10e located at the bottom of the plasma processing chamber 10. The exhaust system 40 may also include a pressure regulating valve and a vacuum pump. The pressure within the plasma processing space 10s is adjusted by the pressure regulating valve. The vacuum pump may also include a turbomolecular pump, a dry vacuum pump, or a combination thereof.

[0023] The power supply system 30 includes a high-frequency power supply 31 and a bias power supply 32. The high-frequency power supply 31 constitutes a plasma generation unit 12 in one embodiment. The high-frequency power supply 31 is configured to generate source high-frequency power RF. The source high-frequency power RF has a source frequency fRF. That is, the source high-frequency power RF has a sinusoidal waveform with a frequency of the source frequency fRF. The source frequency fRF can be a frequency in the range of 10 MHz to 150 MHz. The high-frequency power supply 31 is configured to be electrically connected to a high-frequency electrode via a matching device 33, supplying the source high-frequency power RF to the high-frequency electrode. The high-frequency electrode can also be at least one electrode or an upper electrode disposed in a conductive member, ceramic member 1111a, or base plate 1110. The matching device 33 has a variable impedance. The variable impedance of the matching device 33 is set in a manner that reduces the self-reflection of the source high-frequency power RF from the load. When the source high-frequency power RF is supplied to the high-frequency electrode, plasma is generated from the gas in the chamber 10.

[0024] The bias power supply 32 is configured to generate a bias voltage BE. The bias power supply 32 is electrically coupled to the substrate support portion 11. The bias power supply 32 is configured to be electrically connected to a bias electrode within the substrate support portion 11, and the bias voltage BE is periodically applied to the bias electrode. The bias electrode may also be at least one electrode disposed within a conductive member or ceramic member 1111a of the base 1110. When the bias voltage BE is applied to the bias electrode, ions from the plasma are attracted to the substrate W.

[0025] Referring below to Figures 3 and 4. Figure 4 is a timing diagram associated with an example of a plasma processing apparatus according to an exemplary embodiment. As shown in Figure 4, the bias voltage BE has a pulse waveform and is periodically applied to the bias electrode. The pulse waveform includes voltage pulses. The voltage pulses in the pulse waveform can also be DC voltage pulses. As shown in Figure 4, the voltage pulses in the pulse waveform can also have negative polarity. The pulse waveform of the bias voltage BE can also be a rectangular wave, a triangular wave, or any waveform. The pulse waveform of the bias voltage BE has a waveform period (refer to the waveform period CYb or waveform period CYc in Figure 4). The bias voltage BE has a bias frequency that is the reciprocal of the duration of the waveform period. The bias frequency is lower than the source frequency. The bias frequency can be set in the range of 100 kHz to 60 MHz.

[0026] The method MT will now be described. The plasma treatment apparatus 1 will also be described in more detail.

[0027] As shown in Figure 1, method MT includes steps STa, STb, and STc. Method MT may also include step STd, which is performed after step STb and before step STc. Method MT may also include step STe, which is performed after step STb and before step STd.

[0028] In step STa of method MT, the substrate W is placed on the substrate support surface of the substrate support portion 11. The substrate support surface is the upper surface of the central region 111a or the electrostatic chuck 1111.

[0029] In step STb, the film on substrate W is etched. In step STb, plasma is generated from the etching gas within chamber 10. The film may also be a silicon-containing film such as silicon oxide. The etching gas may also contain fluorocarbon gas. The etching gas may further include oxygen-containing gas and / or fluorine-containing gas. The oxygen-containing gas may also be oxygen gas (O₂ gas). The fluorine-containing gas may also be nitrogen trifluoride gas. In step STb, the film on substrate W is etched by chemical species such as ions and / or free radicals from the plasma.

[0030] In step STb, the gas supply unit 20, the exhaust system 40, the plasma generation unit 12 (in one example, a high-frequency power supply 31), and the bias power supply 32 are controlled by the control unit 2. In step STb, etching gas is supplied from the gas supply unit 20 into the chamber 10. In step STb, the pressure inside the chamber 10 is set to a specified pressure by the exhaust system 40. In step STb, plasma is generated from the etching gas by the plasma generation unit 12. Specifically, high-frequency power RF is supplied to the high-frequency electrodes from the high-frequency power supply 31, and plasma is generated from the etching gas inside the chamber 10.

[0031] In step STb, a bias voltage BE is periodically applied from the bias power supply 32 to the bias electrode. The bias frequency of the bias voltage BE in step STb is set to the bias frequency fBb. The bias frequency fBb is the reciprocal of the waveform period CYb and duration CLb (refer to Figure 4) of the pulse waveform of the bias voltage BE in step STb. Furthermore, in step STb, the duty cycle of the pulse waveform of the bias voltage BE is set to the duty cycle ODb. The duty cycle ODb is the ratio of the duration of period PONb to the duration CLb of the waveform period CYb. Period PONb is the duration of the voltage pulse output in the bias voltage BE within the waveform period CYb.

[0032] In method MT, in step STep following step STb, the substrate W is removed from chamber 10. Subsequently, step STe can also be performed in method MT. In step STe, chamber 10 is cleaned while no object is placed on the substrate support surface. In step STe, a plasma is generated within chamber 10 by a self-cleaning gas for cleaning. The cleaning gas used in step STe may also include fluorocarbon gas. The cleaning gas used in step STe may further include an oxygen-containing gas. The oxygen-containing gas may also be oxygen (O2 gas). In step STe, the surfaces within chamber 10 are cleaned by chemical species such as ions and / or free radicals from the plasma.

[0033] In step STe, the gas supply unit 20, the exhaust system 40, the plasma generation unit 12 (in one example, a high-frequency power supply 31), and the bias power supply 32 are controlled by the control unit 2. In step STe, cleaning gas is supplied from the gas supply unit 20 into the chamber 10. In step STe, the pressure inside the chamber 10 is set to a specified pressure by the exhaust system 40. In step STe, plasma is generated from the cleaning gas by the plasma generation unit 12. Specifically, high-frequency power RF is supplied from the high-frequency power supply 31 to the high-frequency electrodes, and plasma is generated from the cleaning gas inside the chamber 10. In step STe, the bias power supply 32 may also not apply a bias voltage BE to the bias electrodes.

[0034] Next, in method MT, step STdp is performed. In step STdp, a dummy substrate is placed on the substrate support surface. Next, in method MT, step STd may also be performed. In step STd, with the dummy substrate placed on the substrate support surface, the chamber 10 is cleaned. In step STd, for cleaning, plasma is generated from an oxygen-containing gas within the chamber 10. The oxygen-containing gas may also be oxygen (O2 gas). In step STd, the gas supplied to the chamber 10 may also be only an oxygen-containing gas. In step STd, the surface within the chamber 10 is cleaned by chemical species such as ions and / or free radicals from the plasma.

[0035] In step STd, the gas supply unit 20, the exhaust system 40, the plasma generation unit 12 (in one example, a high-frequency power supply 31), and the bias power supply 32 are controlled by the control unit 2. In step STd, oxygen-containing gas is supplied from the gas supply unit 20 into the chamber 10. In step STd, the pressure inside the chamber 10 is set to a specified pressure by the exhaust system 40. In step STd, plasma is generated from the oxygen-containing gas by the plasma generation unit 12. Specifically, high-frequency power RF is supplied from the high-frequency power supply 31 to the high-frequency electrode source, and plasma is generated from the oxygen-containing gas inside the chamber 10. In step STd, the bias power supply 32 may also not apply a bias voltage BE to the bias electrode.

[0036] Next, in method MT, step STc is performed. In step STc, chamber 10 is cleaned. Step STc can also be performed with a dummy substrate mounted on the substrate support surface. In step STc, plasma is generated within chamber 10 from a self-cleaning gas. The cleaning gas may also include fluorocarbon gases such as CF4. The cleaning gas may further include oxygen-containing gases. The oxygen-containing gas may also be oxygen (O2 gas). The cleaning gas may further include rare gases. The rare gas may also be argon. In step STc, the surface within chamber 10 is cleaned by chemical species such as ions and / or free radicals from the plasma.

[0037] In step STc, the gas supply unit 20, the exhaust system 40, the plasma generation unit 12 (in one example, a high-frequency power supply 31), and the bias power supply 32 are controlled by the control unit 2. In step STc, cleaning gas is supplied from the gas supply unit 20 into the chamber 10. In step STc, the pressure inside the chamber 10 is set to a specified pressure by the exhaust system 40. In step STc, plasma is generated from the cleaning gas by the plasma generation unit 12. Specifically, high-frequency power RF is supplied from the high-frequency power supply 31 to the high-frequency electrode source, and plasma is generated from the cleaning gas inside the chamber 10.

[0038] In step STc, a bias voltage BE is periodically applied from the bias power supply 32 to the bias electrode. The bias frequency of the bias voltage BE in step STc is set to the bias frequency fBc. The bias frequency fBc is the reciprocal of the waveform period CYc and duration CLc (refer to Figure 4) of the pulse waveform of the bias voltage BE in step STc. Furthermore, in step STc, the duty cycle of the pulse waveform of the bias voltage BE is set to the duty cycle ODC. The duty cycle ODC is the ratio of the duration of the period PONc to the duration CLc of the waveform period CYc. The period PONc is the duration of the voltage pulse output in the bias voltage BE within the waveform period CYc.

[0039] In step STc, the bias power supply 32 sets the bias frequency fBc to a value higher than the bias frequency fBb in step STb. This improves the cleaning and removal performance of metallic substances adhering to the surface within chamber 10 during step STc. Furthermore, the metal may include aluminum and / or yttrium. These metals are generated from the surfaces exposed to the plasma within chamber 10 during the etching process in step STb and adhere to the surface within chamber 10.

[0040] In step STc, the bias power supply 32 can also be set to a higher duty cycle than the duty cycle ODb in step STb (ODc). In this case, the energy of the ions supplied to the metallic-like substances adhering to the surface of chamber 10 in step STc is higher. Therefore, the removal performance of this substance in step STc can be further improved.

[0041] In addition to setting the bias frequency fBc to a value higher than the bias frequency fBb in step STc, the bias power supply 32 may also set the absolute value of the voltage level of the voltage pulse in the bias voltage BE in step STc to a value greater than the absolute value of the voltage level of the voltage pulse in the bias voltage BE in step STb.

[0042] The above descriptions illustrate various exemplary embodiments, but the embodiments are not limited to these exemplary embodiments. Various additions, omissions, substitutions, and modifications are also possible. Furthermore, elements from different embodiments can be combined to form other embodiments.

[0043] For example, in another embodiment, the plasma processing apparatus, as described in U.S. Application Publication No. 2021 / 0074524 (U.S. Application No. 17 / 015100), may also have one or more bias power supplies. As described in that U.S. application publication, the plasma processing apparatus may also supply bias voltage BE, as bias power, to two or more bias electrodes within the substrate support from one or more bias power supplies. Such a plasma processing apparatus can be used in the aforementioned plasma processing method. Furthermore, the entire contents of that U.S. application are incorporated herein by reference.

[0044] The first and second experiments performed using the plasma processing apparatus 1 for evaluating method MT will now be described. In both the first and second experiments, method MT was performed with a wafer attached to the ring assembly 112. In step STb, an etching gas containing fluorocarbon gas, oxygen, and nitrogen trifluoride gas was used to etch the silicon oxide film on the sample substrate. Next, in step STe, without any object placed on the substrate support surface, the chamber 10 was cleaned using a cleaning gas containing fluorocarbon gas and oxygen. Next, in step STd, with a dummy substrate placed on the substrate support surface, oxygen was used to clean the chamber 10. Then, in step STc, with a dummy substrate placed on the substrate support surface, a cleaning gas containing fluorocarbon gas, argon gas, and oxygen was used to clean the chamber 10. The bias frequency fBb in step STb was 400 kHz. In Experiment 1, the bias frequency fBc in step STc was set to 400 kHz. In Experiment 2, the bias frequency fBc in step STc was set to 600 kHz.

[0045] In Experiments 1 and 2, the amount of aluminum (Al) and yttrium (Y) adhering to the wafer per 1 cm² after step STc was measured. The results are shown in Figure 5. In Figure 5, the horizontal axis represents the bias frequency in step STc, and the vertical axis represents the amount of metal adhering to the wafer per 1 cm² after step STc. As shown in Figure 5, the amount of aluminum and yttrium adhering to the wafer per 1 cm² when the bias frequency in step STc is 600 kHz is lower than the corresponding amount when the bias frequency in step STc is 400 kHz. Based on this, it was confirmed that by setting the bias frequency in step STc to a frequency higher than that in step STb, the cleaning and removal performance of metallic substances adhering to the surface of chamber 10 in step STc can be improved.

[0046] Various exemplary embodiments included in this invention are described below in [E1] to [E25].

[0047] [E1] A plasma treatment method comprising the following steps: (a) A substrate is placed on the substrate support surface of a substrate support portion disposed within the cavity of the plasma processing apparatus; (b) Etching the film on the substrate using plasma generated by self-etching gas within the aforementioned chamber; and (c) The chamber is cleaned using plasma generated by a self-cleaning gas; In (b) and (c) above, a bias voltage containing a DC voltage pulse and having a pulse waveform is periodically applied to the bias electrode of the substrate support portion. The aforementioned bias voltage has a bias frequency that is the reciprocal of the duration of the period of the aforementioned pulse waveform. The bias frequency in (c) above is higher than the bias frequency in (b) above.

[0048] [E2] In the plasma processing method of technical solution 1, the duty cycle of the pulse waveform of the bias voltage in (c) is higher than that in (b).

[0049] [E3] For example, in plasma processing methods such as E1 or E2, each of the aforementioned etching gas and cleaning gas contains fluorocarbon gas.

[0050] [E4] In the plasma treatment method of E3, the aforementioned cleaning gas further includes an oxygen-containing gas.

[0051] [E5] The plasma treatment method, such as any one of E1 to E4, further includes the following steps: (d) Between (b) and (c) above, with a dummy substrate mounted on the substrate support, the cavity is cleaned using plasma generated from an oxygen-containing gas. In (d) above, the bias voltage is not applied to the bias electrode.

[0052] [E6] The plasma treatment method of E5 further includes the following steps: (e) between (b) and (d) above, in a state where no object is placed on the substrate support surface, cleaning the cavity using plasma formed from other cleaning gases.

[0053] [E7] In the plasma processing method of E6, in the above (e), the bias voltage is not applied to the bias electrode.

[0054] [E8] For example, in plasma treatment methods such as E6 or E7, the other cleaning gases mentioned above include fluorocarbon gases.

[0055] [E9] For example, in the plasma treatment method of E8, the aforementioned other cleaning gases further include oxygen-containing gases.

[0056] [E10] The plasma processing method of any one of E1 to E9, wherein step (c) is performed with a dummy substrate placed on the substrate support surface.

[0057] [E11] The plasma processing method of any one of E1 to E10, wherein the pulse of the aforementioned DC voltage has a negative polarity.

[0058] [E12] In any of the plasma processing methods E1 to E11, the absolute value of the voltage level of the voltage pulse in (c) above is greater than the absolute value of the voltage level of the voltage pulse in (b) above.

[0059] [E13] A plasma treatment apparatus comprising: chamber; A substrate support portion having a substrate support surface and a bias electrode is disposed within the aforementioned cavity; A gas supply unit is configured to supply gas to the aforementioned chamber; The plasma generating unit is configured to generate plasma within the aforementioned chamber; A bias power supply is configured to periodically apply a bias voltage, comprising a DC voltage pulse and having a pulse waveform, to the bias electrodes, wherein the bias voltage has a bias frequency that is the reciprocal of the duration of the pulse waveform period; and The control unit is configured to control the gas supply unit, the plasma generation unit, and the bias power supply. The aforementioned control unit is configured as follows: (b) Controlling the gas supply unit, the plasma generation unit, and the bias power supply to generate plasma from the etching gas in the chamber to etch the film on the substrate placed on the substrate support unit; (c) Control the gas supply unit, the plasma generation unit, and the bias power supply to generate plasma from the self-cleaning gas in the chamber to clean the chamber; The above bias power supply, In (b) and (c) above, the bias voltage is periodically applied to the bias electrode. The bias frequency in (c) above is set to a frequency higher than the bias frequency in (b) above.

[0060] [E14] For example, in the plasma processing apparatus of E13, the bias power supply is configured to set the duty cycle of the pulse waveform of the bias voltage in (c) to a value higher than the duty cycle in (b).

[0061] [E15] Such as plasma processing apparatuses of E13 or E14, wherein each of the aforementioned etching gas and cleaning gas contains fluorocarbon gas.

[0062] [E16] For example, in the plasma treatment apparatus of E15, the aforementioned cleaning gas further includes an oxygen-containing gas.

[0063] [E17] Such as the plasma processing apparatus of any of E13 to E16, wherein The aforementioned control unit is configured as follows: (d) Control the gas supply unit and the bias power supply so that, between (b) and (c), with a dummy substrate mounted on the substrate support, plasma is generated from oxygen-containing gas within the cavity to clean the cavity. In the above (d) scenario, the bias power supply does not apply the bias voltage to the bias electrode.

[0064] [E18] For example, in the plasma processing apparatus of E17, the aforementioned control unit is configured as follows: (e) Control the gas supply unit and the bias power supply to clean the chamber by generating plasma from other cleaning gases in the chamber between (b) and (d) when no object is placed on the substrate support surface.

[0065] [E19] In the plasma processing apparatus of E18, the bias power supply does not apply the bias voltage to the bias electrode in (e).

[0066] [E20] Such as plasma treatment apparatus E18 or E19, wherein the other cleaning gases mentioned above include fluorocarbon gases.

[0067] [E21] For example, in the plasma treatment apparatus of E20, the aforementioned other cleaning gases further include oxygen-containing gases.

[0068] [E22] The plasma processing apparatus of any one of E13 to E21, wherein the above (c) is performed with a dummy substrate placed on the substrate support surface.

[0069] [E23] The plasma processing apparatus of any one of E13 to E22, wherein the pulse of the aforementioned DC voltage has a negative polarity.

[0070] [E24] The plasma processing apparatus of any one of E13 to E23, wherein the bias power supply is configured to set the absolute value of the voltage level of the voltage pulse in (c) to be greater than the absolute value of the voltage level of the voltage pulse in (b).

[0071] [E25] A plasma treatment apparatus comprising: chamber; A substrate support portion having a substrate support surface and a bias electrode is disposed within the aforementioned cavity; A gas supply unit is configured to supply gas to the aforementioned chamber; The plasma generating unit is configured to generate plasma within the aforementioned chamber; A bias power supply is configured to periodically apply a bias voltage, comprising a DC voltage pulse and having a pulse waveform, to the bias electrodes, wherein the bias voltage has a bias frequency that is the reciprocal of the duration of the pulse waveform period; and The control unit is configured to control the gas supply unit, the plasma generation unit, and the bias power supply. The aforementioned control unit is configured as follows: (b) Controlling the gas supply unit, the plasma generation unit, and the bias power supply to generate plasma from the etching gas in the chamber to etch the film on the substrate placed on the substrate support unit; (c) Control the gas supply unit, the plasma generation unit, and the bias power supply to generate plasma from the self-cleaning gas in the chamber to clean the chamber; The above bias power supply, In (b) and (c) above, the bias voltage is periodically applied to the bias electrode. The absolute value of the voltage level of the voltage pulse in (c) above is set to a value that is larger than the absolute value of the voltage level of the voltage pulse in (b) above.

[0072] Based on the foregoing description, it should be understood that the various embodiments of the present invention have been described in this specification for illustrative purposes, and various modifications may be made without departing from the scope and spirit of the invention. Therefore, the various embodiments disclosed in this specification are not intended to be limiting, and the true scope and spirit are indicated by the appended claims.

[0073] 1: Plasma treatment device 2: Control Department 2a: Computer 2a1: Processing Department 2a2: Memory Department 2a3: Communication Interface 10: Chamber 10a: Sidewall 10e: Gas exhaust outlet 10s: Plasma processing space 11:Substrate support department 12: Plasma Generation Unit 13: Cluster Head 13a: Gas supply port 13b: Gas diffusion chamber 13c: Gas inlet 20: Gas Supply Department 21: Gas Source 22: Flow controller 30: Power System 31: High-frequency power supply 32: Bias power supply 33: Matcher 40: Exhaust System 111: Ontology Department 111a: Central Region 111b: Annular region 112: Ring Component 1110:Abutment 1110a: Flow path 1111: Electrostatic Chuck 1111a: Ceramic components 1111b: Electrostatic electrode MT: Method STa: Steps STb: Steps STep: Steps STe: Steps STdp: Steps STd: Steps STc: Steps

Claims

1. A plasma processing method comprising the steps of: (a) placing a substrate on a substrate support surface of a substrate support portion disposed in a cavity of a plasma processing apparatus; (b) etching a film on the substrate in the cavity using plasma generated by an etching gas; and (c) cleaning the cavity using plasma generated by a cleaning gas; wherein in (b) and (c), a bias voltage comprising a DC voltage pulse and having a pulse waveform is periodically applied to a bias electrode of the substrate support portion, the bias voltage having a bias frequency that is the reciprocal of the duration of the waveform period of the pulse waveform, and the bias frequency in (c) being higher than the bias frequency in (b).

2. The plasma processing method of claim 1, wherein the duty cycle of the pulse waveform of the bias voltage in (c) above is higher than the duty cycle in (b) above.

3. The plasma processing method of claim 1, wherein each of the etching gas and the cleaning gas comprises a fluorocarbon gas.

4. The plasma treatment method as claimed in claim 3, wherein the aforementioned cleaning gas further includes an oxygen-containing gas.

5. The plasma processing method according to any one of claims 1 to 4 further includes the following steps: (d) between (b) and (c), with a dummy substrate placed on the substrate support, cleaning the chamber using plasma generated from an oxygen-containing gas, wherein in (d), the bias voltage is not applied to the bias electrode.

6. The plasma processing method of claim 5 further includes the following steps: (e) between (b) and (d) above, in a state where no object is placed on the substrate support surface, cleaning the chamber using plasma formed from other cleaning gases.

7. The plasma processing method of claim 6, wherein in (e) above, the bias voltage is not applied to the bias electrode.

8. The plasma treatment method as claimed in claim 6, wherein the other cleaning gases mentioned above include fluorocarbon gases.

9. The plasma treatment method of claim 8, wherein the aforementioned other cleaning gases further include oxygen-containing gases.

10. The plasma processing method of any one of claims 1 to 4, wherein step (c) is performed with a dummy substrate mounted on the substrate support surface.

11. The plasma processing method of any one of claims 1 to 4, wherein the pulse of the DC voltage is negative.

12. The plasma processing method of any one of claims 1 to 4, wherein the absolute value of the voltage level of the voltage pulse in (c) above is greater than the absolute value of the voltage level of the voltage pulse in (b) above.

13. A plasma processing apparatus comprising: a chamber; a substrate support having a substrate support surface and a bias electrode disposed within the chamber; a gas supply unit configured to supply gas to the chamber; a plasma generation unit configured to generate plasma within the chamber; a bias power supply configured to periodically apply a bias voltage comprising a DC voltage pulse and having a pulse waveform to the bias electrode, wherein the bias voltage has a bias frequency that is the reciprocal of the duration of the waveform period of the pulse waveform; and a control unit configured to control the gas supply unit, the plasma generation unit, and the bias power supply; wherein the control unit is configured to: (b) control the gas supply unit, the plasma generation unit, and the bias power supply to etch a film on the substrate placed on the substrate support by generating plasma from etching gas within the chamber. (c) The gas supply unit, the plasma generation unit, and the bias power supply are controlled to generate plasma in the self-cleaning gas in the chamber to clean the chamber; The bias power supply periodically applies the bias voltage to the bias electrode in (b) and (c), and sets the bias frequency in (c) to a frequency higher than the bias frequency in (b).

14. The plasma processing apparatus of claim 13, wherein the bias power supply is configured to set the duty cycle of the pulse waveform of the bias voltage in (c) to a value higher than the duty cycle in (b).

15. The plasma processing apparatus of claim 13, wherein each of the etching gas and the cleaning gas comprises a fluorocarbon gas.

16. The plasma treatment apparatus of claim 15, wherein the cleaning gas further includes an oxygen-containing gas.

17. The plasma processing apparatus of any one of claims 13 to 16, wherein the control unit is configured to (d) control the gas supply unit and the bias power supply to clean the chamber by generating plasma from oxygen-containing gas in the chamber between (b) and (c), with a dummy substrate placed on the substrate support, and wherein the bias power supply does not apply the bias voltage to the bias electrode in (d).

18. The plasma processing apparatus of claim 17, wherein the control unit is configured to (e) control the gas supply unit and the bias power supply to clean the chamber by generating plasma from other cleaning gases in the chamber between (b) and (d) when no object is placed on the substrate support surface.

19. The plasma processing apparatus of claim 18, wherein the bias power supply does not apply the bias voltage to the bias electrode in (e) above.

20. The plasma treatment apparatus of claim 18, wherein the other cleaning gas mentioned above includes fluorocarbon gas.

21. The plasma treatment apparatus of claim 20, wherein the aforementioned other cleaning gases further include oxygen-containing gases.

22. The plasma processing apparatus of any one of claims 13 to 16, wherein the above (c) is performed with a dummy substrate mounted on the substrate support surface.

23. The plasma processing apparatus of any one of claims 13 to 16, wherein the pulse of the DC voltage is negative.

24. The plasma processing apparatus of any one of claims 13 to 16, wherein the bias power supply is configured to set the absolute value of the voltage level of the voltage pulse in (c) to be greater than the absolute value of the voltage level of the voltage pulse in (b).

25. A plasma processing apparatus comprising: a chamber; a substrate support having a substrate support surface and a bias electrode disposed within the chamber; a gas supply unit configured to supply gas to the chamber; a plasma generation unit configured to generate plasma within the chamber; a bias power supply configured to periodically apply a bias voltage comprising a DC voltage pulse and having a pulse waveform to the bias electrode, wherein the bias voltage has a bias frequency that is the reciprocal of the duration of the period of the pulse waveform; and a control unit configured to control the gas supply unit, the plasma generation unit, and the bias power supply; wherein the control unit is configured to: (b) control the gas supply unit, the plasma generation unit, and the bias power supply to etch a film on the substrate placed on the substrate support by generating plasma from etching gas within the chamber. (c) Control the gas supply unit, the plasma generation unit, and the bias power supply to generate plasma in the self-cleaning gas in the chamber to clean the chamber; The bias power supply periodically applies the bias voltage to the bias electrode in (b) and (c), and sets the absolute value of the voltage level of the voltage pulse in (c) to a value larger than the absolute value of the voltage level of the voltage pulse in (b).

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