Plasma processing method and plasma processing apparatus

Abstract

To provide a technique of cleaning a mounting stage of a plasma processing apparatus.SOLUTION: The present invention provides a plasma processing method executed in a plasma processing apparatus. The plasma processing apparatus comprises: a chamber; and a substrate support part that is arranged in the chamber. The substrate support contains: a first region constructed so as to support a substrate; a second region surrounding an outer periphery of the first region; and an annular-shaped member to be supported onto the second region. The plasma processing method contains a step (a) of cleaning the inside of the chamber in a state where the substrate is not supported onto the substrate support part. The step (a) contains: a step (a1) of setting a temperature of an annular-like member to a temperature that is different from a temperature of the first region; and a step (a2) of generating plasma from a cleaning gas in the chamber.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] Exemplary embodiments of the present disclosure relate to a plasma processing method and a plasma processing apparatus.

Background Art

[0002] Patent Document 1 discloses a technique for cleaning a mounting table of a plasma processing apparatus.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present disclosure provides a technique for improving the cleaning efficiency inside a chamber.

Means for Solving the Problems

[0005] In one exemplary embodiment of the present disclosure, there is provided a plasma processing method executed in a plasma processing apparatus, the plasma processing apparatus including a chamber and a substrate support portion disposed inside the chamber, the substrate support portion including a first region configured to support a substrate, a second region surrounding the outer periphery of the first region, and an annular member supported on the second region, the plasma processing method including a step of cleaning the inside of the chamber with no substrate supported on the substrate support portion, and the step (a) including (a1) setting the temperature of the annular member to a temperature different from the temperature of the first region, and (a2) generating plasma from a cleaning gas inside the chamber.

Effects of the Invention

[0006] According to one exemplary embodiment of the present disclosure, a technique for improving the cleaning efficiency in a chamber can be provided.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Modes for Carrying Out the Invention

[0008] Hereinafter, each embodiment of the present disclosure will be described.

[0009] In one exemplary embodiment, there is provided a plasma processing method executed in a plasma processing apparatus, the plasma processing apparatus including: a chamber; a substrate support part disposed in the chamber, the substrate support part including a first region configured to support a substrate, a second region surrounding the outer periphery of the first region, and an annular member supported on the second region; and the plasma processing method including: (a) a step of cleaning the inside of the chamber in a state where no substrate is supported on the substrate support part, and (a) including: (a1) setting the temperature of the annular member to a temperature different from the temperature of the first region; and (a2) generating plasma from a cleaning gas in the chamber.

[0010] In one exemplary embodiment, in (a1), the temperature of the annular member is set based on the distance between the annular member and the outer periphery of the first region.

[0011] In one exemplary embodiment, in (a1), the temperature of the annular member is set to a temperature lower than the temperature of the first region.

[0012] In one exemplary embodiment, in (a1), the temperature of the annular member is set to a temperature higher than the temperature of the first region.

[0013] In one exemplary embodiment, the plasma processing method further includes a step of generating plasma from a processing gas in the chamber with the substrate supported on the substrate support portion in (b), and in (a1), the temperatures of the annular member and the first region are set such that the temperature difference between the temperature of the annular member and the temperature of the first region is larger than the temperature difference in (b).

[0014] In one exemplary embodiment, in (a1), the temperature of the annular member is set to a temperature lower than the temperature of the annular member in (b).

[0015] In one exemplary embodiment, in (a1), the temperature of the annular member is set to a temperature higher than the temperature of the annular member in (b).

[0016] In one exemplary embodiment, in (a1), the temperature of the first region is set to a temperature higher than the temperature of the first region in (b).

[0017] In one exemplary embodiment, in (a1), the temperature of the first region is set to a temperature higher than the temperature of the first region in (b).

[0018] In one exemplary embodiment, in (b), the processing gas includes a reaction gas, and the substrate is etched by the plasma generated from the processing gas.

[0019] In one exemplary embodiment, in (b), the processing gas includes a cleaning gas, and the inside of the chamber is cleaned by the plasma generated from the processing gas.

[0020] In one exemplary embodiment, (a) is performed after (b), and in (a1), the temperature of the annular member is set based on the distance between the deposit attached to the first region and the annular member.

[0021] In one exemplary embodiment, at least a part of the period of performing (a1) and the period of performing (a2) overlap.

[0022] In one exemplary embodiment, (a1) and (a2) are performed simultaneously.

[0023] In one exemplary embodiment, the plasma processing apparatus is provided with a recess configured to supply a heat transfer fluid between the annular member and the second region, and in (a1), the temperature of the annular member is controlled by adjusting the pressure of the heat transfer fluid supplied to the recess.

[0024] In one exemplary embodiment, the plasma processing apparatus further includes a first chuck electrode provided below the first region and a second chuck electrode provided below the second region and independently controllable from the first chuck electrode. In (a1), the temperature of the annular member is controlled by adjusting the voltage applied to the second chuck electrode.

[0025] In one exemplary embodiment, the plasma processing apparatus includes a first heater provided below the first region and a second heater provided below the second region and independently controllable from the first heater. In (a1), the temperature of the annular member is controlled by adjusting the power supplied to the second heater.

[0026] In one exemplary embodiment, there is provided a plasma processing apparatus including a chamber, a substrate support disposed in the chamber, the substrate support including a first region configured to support a substrate, a second region surrounding an outer periphery of the first region, and an annular member supported on the second region, and a control unit. The control unit is configured to execute control for cleaning the interior of the chamber in a state where no substrate is supported on the substrate support, and (a) includes (a1) setting a temperature of the annular member to a temperature different from that of the first region, and (a2) generating plasma from a cleaning gas in the chamber.

[0027] Hereinafter, each embodiment of the present disclosure will be described in detail with reference to the drawings. In the drawings, the same or similar elements are denoted by the same reference numerals, and redundant descriptions are omitted. Unless otherwise specified, the positional relationships such as up, down, left, and right are described based on the positional relationships shown in the drawings. The dimensional ratios in the drawings do not represent actual ratios, and the actual ratios are not limited to the ratios shown in the drawings.

[0028] <Configuration Example of Plasma Processing System> FIG. 1 is a diagram for explaining a configuration example 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. The plasma processing chamber 10 also has at least one gas supply port for supplying at least one processing gas to the plasma processing space and at least one gas discharge port for discharging gas from the plasma processing space. The gas supply port is connected to a gas supply unit 20 described later, and the gas discharge port is connected to an exhaust system 40 described later. The substrate support 11 is disposed in the plasma processing space and has a substrate support surface for supporting a substrate.

[0029] The plasma generation unit 12 is configured to generate plasma from at least one process gas supplied into the plasma processing space. The plasma formed in the plasma processing space may be capacitively coupled plasma (CCP), inductively coupled plasma (ICP), electron-cyclotron-resonance plasma (ECR plasma), helicon wave plasma (HWP), surface wave plasma (SWP), or the like. Also, various types of plasma generation units including an alternating current (AC) plasma generation unit and a direct current (DC) plasma generation unit may be used. In one embodiment, the AC signal (AC power) used in the AC plasma generation unit has a frequency in the range of 100 kHz to 10 GHz. Accordingly, the AC signal includes a radio frequency (RF) signal and a microwave signal. In one embodiment, the RF signal has a frequency in the range of 100 kHz to 150 MHz.

[0030] The control unit 2 processes computer-executable instructions for causing the plasma processing apparatus 1 to execute various processes described in the present disclosure. The control unit 2 can be configured to control each element of the plasma processing apparatus 1 so as to execute the various processes described herein. In one embodiment, part or all of the control unit 2 may be included in the plasma processing apparatus 1. The control unit 2 may include a processing unit 2a1, a storage unit 2a2, and a communication interface 2a3. The control unit 2 is realized by, for example, a computer 2a. The processing unit 2a1 can be configured to perform various control operations by reading a program from the storage unit 2a2 and executing the read program. This program may be stored in the storage unit 2a2 in advance, or may be acquired via a medium when necessary. The acquired program is stored in the storage unit 2a2 and read from the storage unit 2a2 by the processing unit 2a1 and executed. The medium may be various storage media readable by the computer 2a, or may be a communication line connected to the communication interface 2a3. The processing unit 2a1 may be a CPU (Central Processing Unit). The storage unit 2a2 may include a RAM (Random Access Memory), a ROM (Read Only Memory), an HDD (Hard Disk Drive), an SSD (Solid State Drive), 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).

[0031] Hereinafter, a configuration example of a capacitively coupled plasma processing apparatus as an example of the plasma processing apparatus 1 will be described. FIG. 2 is a diagram for explaining a configuration example of a capacitively coupled plasma processing apparatus.

[0032] The capacitively coupled plasma processing apparatus 1 includes a plasma processing chamber 10, a gas supply unit 20, a power supply 30, and an exhaust system 40. The plasma processing apparatus 1 also includes a substrate support unit 11 and a gas introduction unit. The gas introduction unit is configured to introduce at least one processing gas into the plasma processing chamber 10. The gas introduction unit includes a shower head 13. The substrate support unit 11 is disposed in the plasma processing chamber 10. The shower head 13 is disposed above the substrate support unit 11. In one embodiment, the shower head 13 constitutes at least a part of the ceiling of the plasma processing chamber 10. The plasma processing chamber 10 has a plasma processing space 10s defined by the shower head 13, the side wall 10a of the plasma processing chamber 10, and the substrate support unit 11. The plasma processing chamber 10 is grounded. The shower head 13 and the substrate support unit 11 are electrically insulated from the housing of the plasma processing chamber 10.

[0033] The substrate support unit 11 includes a main body unit 111 and a ring assembly 112. The main body unit 111 has a central region 111a for supporting the substrate W and an annular region 111b for supporting the ring assembly 112. A wafer is an example of the substrate W. The annular region 111b of the main body unit 111 surrounds the central region 111a of the main body unit 111 in a plan view. The substrate W is disposed on the central region 111a of the main body unit 111, and the ring assembly 112 is disposed on the annular region 111b of the main body unit 111 so as to surround the substrate W on the central region 111a of the main body unit 111. Accordingly, the central region 111a is also referred to as a substrate support surface for supporting the substrate W, and the annular region 111b is also referred to as a ring support surface for supporting the ring assembly 112.

[0034] In one embodiment, the main body portion 111 includes a base 1110 and an electrostatic chuck 1111. The base 1110 includes a conductive member. The conductive member of the base 1110 can function as a lower electrode. 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. Note that other members surrounding the electrostatic chuck 1111, such as an annular electrostatic chuck or an annular insulating member, may have the annular region 111b. In this case, the ring assembly 112 may be disposed on the annular electrostatic chuck or the annular insulating member, or may be disposed on both the electrostatic chuck 1111 and the annular insulating member. Also, at least one RF / DC electrode coupled to an RF power supply 31 and / or a DC power supply 32, which will be described later, may be disposed within the ceramic member 1111a. In this case, the at least one RF / DC electrode functions as a lower electrode. When a bias RF signal and / or a DC signal, which will be described later, is supplied to the at least one RF / DC electrode, the RF / DC electrode is also referred to as a bias electrode. Note that the conductive member of the base 1110 and the at least one RF / DC electrode may function as a plurality of lower electrodes. Also, the electrostatic electrode 1111b may function as a lower electrode. Accordingly, the substrate support portion 11 includes at least one lower electrode.

[0035] 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 ring is formed of a conductive material or an insulating material, and the cover ring is formed of an insulating material.

[0036] Further, the substrate support portion 11 may 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 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 in the base 1110, and one or more heaters are disposed in the ceramic member 1111a of the electrostatic chuck 1111. Further, the substrate support portion 11 may include a heat transfer gas supply portion configured to supply a heat transfer gas to a gap between the back surface of the substrate W and the central region 111a.

[0037] The shower head 13 is configured to introduce at least one process gas from the gas supply unit 20 into the plasma processing space 10s. The shower head 13 has at least one gas supply port 13a, at least one gas diffusion chamber 13b, and a plurality of gas introduction ports 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 plurality of gas introduction ports 13c. Further, the shower head 13 includes at least one upper electrode. Note that the gas introduction portion may include, in addition to the shower head 13, one or more side gas injection portions (SGI: Side Gas Injector) attached to one or more openings formed in the side wall 10a.

[0038] 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 the corresponding gas source 21 to the shower head 13 via the corresponding flow controller 22. Each flow controller 22 may include, for example, a mass flow controller or a pressure-controlled flow controller. Further, the gas supply unit 20 may include at least one flow modulation device configured to modulate or pulse the flow rate of at least one process gas.

[0039] 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) to at least one lower electrode and / or at least one upper electrode. Thereby, plasma is formed from at least one processing gas supplied to the plasma processing space 10s. Therefore, the RF power supply 31 can function as at least a part of the plasma generation unit 12. Also, by supplying a bias RF signal to at least one lower electrode, a bias potential is generated on the substrate W, and the ion component in the formed plasma can be drawn into the substrate W.

[0040] In one embodiment, the RF power supply 31 includes a first RF generation unit 31a and a second RF generation unit 31b. The first RF generation unit 31a is coupled to at least one lower electrode and / or at least one upper electrode 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 10 MHz to 150 MHz. In one embodiment, the first RF generation unit 31a may be configured to generate a plurality of source RF signals having different frequencies. The generated one or more source RF signals are supplied to at least one lower electrode and / or at least one upper electrode.

[0041] The second RF generation unit 31b is coupled to at least one lower electrode via at least one impedance matching circuit and is configured to generate a bias RF signal (bias RF power). The frequency of the bias RF signal may be the same as or different from the frequency of the source RF signal. In one embodiment, the bias RF signal has a frequency lower than the frequency of the source RF signal. In one embodiment, the bias RF signal has a frequency in the range of 100 kHz to 60 MHz. In one embodiment, the second RF generation unit 31b may be configured to generate a plurality of bias RF signals having different frequencies. The generated one or more bias RF signals are supplied to at least one lower electrode. Also, in various embodiments, at least one of the source RF signal and the bias RF signal may be pulsed.

[0042] Also, the power supply 30 may include a DC power supply 32 coupled to the plasma processing chamber 10. The DC power supply 32 includes a first DC generation unit 32a and a second DC generation unit 32b. In one embodiment, the first DC generation unit 32a is connected to at least one lower electrode and is configured to generate a first DC signal. The generated first DC signal is applied to at least one lower electrode. In one embodiment, the second DC generation unit 32b is connected to at least one upper electrode and is configured to generate a second DC signal. The generated second DC signal is applied to at least one upper electrode.

[0043] In various embodiments, the first and second DC signals may be pulsed. In this case, a sequence of voltage pulses is applied to at least one lower electrode and / or at least one upper electrode. The voltage pulses may have a pulse waveform that is rectangular, trapezoidal, triangular, or a combination thereof. In one embodiment, a waveform generation unit for generating a sequence of voltage pulses from a DC signal is connected between the first DC generation unit 32a and at least one lower electrode. Accordingly, the first DC generation unit 32a and the waveform generation unit constitute a voltage pulse generation unit. When the second DC generation unit 32b and the waveform generation unit constitute a voltage pulse generation unit, the voltage pulse generation unit is connected to at least one upper electrode. The voltage pulses may have a positive polarity or a negative polarity. Also, the sequence of voltage pulses may include one or more positive-polarity voltage pulses and one or more negative-polarity voltage pulses within one period. Note that the first and second DC generation units 32a, 32b may be provided in addition to the RF power supply 31, or the first DC generation unit 32a may be provided in place of the second RF generation unit 31b.

[0044] The exhaust system 40 may be connected to, for example, a gas outlet 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 adjusted by the pressure regulating valve. The vacuum pump may include a turbo molecular pump, a dry pump, or a combination thereof.

[0045] FIG. 3 is a partially enlarged view for explaining an example of the structure of the substrate support portion 11. In one embodiment, the upper surface of the electrostatic chuck 1111 has a central region 111a that constitutes a support surface for supporting the substrate W and an annular region 111b that constitutes a support surface for supporting the ring assembly 112. The annular region 111b surrounds the outer periphery of the substrate support surface 111a. The central region 111a is an example of a first region. The annular region 111b is an example of a second region.

[0046] In one embodiment, the electrostatic chuck 1111 may have an electrostatic electrode 1111b inside thereof and below the central region 111a. The electrostatic electrode 1111b is an example of a first chuck electrode. The electrostatic electrode 1111b may be a planar electrode corresponding to the shape of the central region 111a. A power supply 56 is connected to the electrostatic electrode 1111b. The electrostatic electrode 1111b generates an electrostatic force according to the voltage applied from the power supply 56. The substrate W is adsorbed and held on the central region 111a by the electrostatic force generated by the electrostatic electrode 1111b. By adjusting the voltage applied from the power supply 56, the adsorption force of the substrate W to the central region 111a and the heat transfer rate between the two change. Thereby, the temperature of the substrate W and the central region 111a may be controlled.

[0047] In one embodiment, the electrostatic chuck 1111 may have electrostatic electrodes 120a and 120b inside thereof and below the annular region 111b. The electrostatic electrodes 120a and 120b are controllable independently of the electrostatic electrode 1111b. The electrostatic electrodes 120a and 120b are an example of second chuck electrodes. The electrostatic electrode 120b is provided outside the electrostatic electrode 120a. The electrostatic electrodes 120a and 120b may be annular electrodes corresponding to the shape of the ring assembly 112.

[0048] Power supplies 58a and 58b are connected to the electrostatic electrodes 120a and 120b, respectively. The power supplies 58a and 58b supply DC voltages to the electrostatic electrodes 120a and 120b, respectively, so that a predetermined potential difference is generated between the electrostatic electrodes 120a and 120b. When a potential difference occurs between the electrostatic electrodes 120a and 120b, an electrostatic force corresponding to the potential difference is generated between the annular region 111b and the ring assembly 112. The ring assembly 112 is adsorbed and held on the annular region 111b by the generated electrostatic force. By adjusting the voltages applied from the power supplies 58a and 58b, the adsorption force of the ring assembly 112 to the annular region 111b and the heat transfer rate between the two change. Thereby, the temperature of the ring assembly 112 and the annular region 111b may be controlled.

[0049] In one embodiment, a heat transfer fluid such as helium gas may be supplied to the space above the central region 111a of the electrostatic chuck 1111 through the pipe 53a and the opening 54a. A control valve 530a is provided in the pipe 53a. By adjusting the flow rate or pressure of the heat transfer fluid with the control valve 530a, the temperature of the substrate W and the central region 111a may be controlled.

[0050] In one embodiment, a recess RC may be provided between the annular region 111b of the electrostatic chuck 1111 and the back surface of the ring assembly 112. A heat transfer fluid such as helium gas may be supplied to the recess RC through the pipe 53b and the opening 54b. The heat transfer medium supplied from the pipe 53b may be the same as or different from the heat transfer medium supplied from the pipe 53a. A control valve 530b is provided in the pipe 53b. By adjusting the flow rate or pressure of the heat transfer fluid with the control valve 530b, the temperature of the ring assembly 112 and the annular region 111b may be controlled.

[0051] In one embodiment, the electrostatic chuck 1111 may have a heater 55a inside thereof and below the central region 111a. The heater 55a may be disposed below the electrostatic electrode 1111b. A heater power supply 57a is connected to the heater 55a. The heater 55a generates heat according to the power supplied from the heater power supply 57a. By adjusting the power supplied from the heater power supply 57a to the heater 55a, the temperature of the substrate W and the central region 111a may be controlled.

[0052] In one embodiment, the electrostatic chuck 1111 may have a heater 55b inside thereof and below the annular region 111b. The heater 55b may be disposed below the electrodes 120a and 120b. A heater power supply 57b is connected to the heater 55b. The heater 55b generates heat according to the power supplied from the heater power supply 57b. By adjusting the power supplied from the heater power supply 57b to the heater 55b, the temperature of the ring assembly 112 and the annular region 111b may be controlled.

[0053] <An Example of Plasma Processing Method> FIG. 4 is a flowchart showing an example of a plasma processing method (hereinafter also referred to as "this processing method") according to one exemplary embodiment. This processing method includes a step ST1 of arranging a substrate, a step ST2 of generating a first plasma, a step ST3 of carrying out the substrate, a step ST4 of controlling the temperature of the substrate support portion, and a step ST5 of generating a second plasma. The processing in each step of FIG. 4 may be executed by the operation of the plasma processing apparatus 1 according to the control of the control unit 2.

[0054] FIG. 5 is a diagram showing an example of the state inside the chamber in step ST2. FIG. 6 is a diagram showing an example of the state inside the chamber in step ST5. FIG. 7 is a diagram showing another example of the state inside the chamber in step ST5. With reference to FIGS. 5 to 7, the plasma processing method shown in FIG. 4 will be described.

[0055] (Step ST1: Arrangement of Substrate) First, in step ST1, the substrate W is carried into the plasma processing chamber 10 (hereinafter also referred to as "chamber 10") of the plasma processing apparatus 1 by a transfer device. The transfer device holds the substrate W so that the substrate W is parallel to the central region 111a of the substrate support portion 11. Then, the substrate W is placed at the tip of a lifter protruding from the central region 111a of the electrostatic chuck 1111. The substrate W is arranged in the central region 111a as the lifter descends. When a predetermined voltage is applied to the electrostatic electrode 1111b, the substrate W is electrostatically adsorbed to the central region 111a.

[0056] In one embodiment, the substrate W may be a patterned substrate having a pattern formed on its surface. The patterned substrate may include a film to be subjected to plasma processing such as etching. Note that, as will be described later in a modification example, the substrate W may be a dummy substrate for protecting the electrostatic chuck 1111.

[0057] In process ST1, the temperature of the substrate support portion 11 may be controlled to a set temperature. In one example, controlling the substrate support portion 11 to the set temperature includes setting the temperature of the heat transfer fluid flowing through the flow path 1110a and the temperatures of the heaters 55a and 55b to the set temperature, or to a temperature different from the set temperature. Note that the timing at which the heat transfer fluid starts to flow through the flow path 1110a may be before, after, or at the same time as the substrate W is placed on the substrate support portion 11. Also, the temperature of the substrate support portion 11 may be controlled to the set temperature before process ST1. That is, after the temperature of the substrate support portion 11 is controlled to the set temperature, the substrate W may be placed on the substrate support portion 11.

[0058] In one embodiment, instead of controlling the substrate support portion 11 to the set temperature, the substrate W may be controlled to the set temperature. Controlling the temperature of the substrate W to the set temperature includes setting the temperature of the substrate support portion 11, the temperature of the heat transfer fluid flowing through the flow path 1110a, and / or the heater temperature to the set temperature, or to a temperature different from the set temperature.

[0059] The temperature of the substrate support portion 11 and / or the substrate W may be similarly controlled in process ST2.

[0060] (Process ST2: Generation of the first plasma) Next, in process ST2, as shown in FIG. 5, the first plasma P1 is generated. The first plasma P1 is generated between the surface of the substrate W and the shower head 13 in the chamber 10 with the substrate W placed on the substrate support portion 11.

[0061] In one embodiment, the first plasma P1 may be generated as follows. That is, first, the gas supply unit 20 supplies a processing gas for generating the first plasma P1 into the plasma processing chamber 10. The processing gas may be, for example, a reaction gas for etching the substrate W. The processing gas may contain an inert gas such as Ar gas. Further, the exhaust system 40 controls the pressure in the chamber 10 to a predetermined set pressure. Then, the first RF generation unit 31a supplies a source RF signal to the substrate support unit 11 or the shower head 13. Also, the second RF generation unit 31b or the first DC generation unit 32a may supply a bias signal to the lower electrode of the substrate support unit 11. As described above, the first plasma P1 is generated in the chamber 10, and the substrate W is subjected to plasma processing such as etching.

[0062] Reaction by-products may be formed during the plasma processing in step ST2. A part of the reaction by-products may adhere to the inside of the chamber 10. For example, a part of the reaction by-products may enter from the gap between the substrate W and the ring assembly 112 to the back side of the substrate W and adhere to the outer periphery (shoulder portion) of the central region 111a of the electrostatic chuck 111 (see the deposit DP in FIGS. 6 and 7).

[0063] (Step ST3: Unloading of the substrate) Next, in step ST3, the substrate W is unloaded from the chamber 10. The application of voltage to the electrostatic electrode 1111b is stopped, and the electrostatic adsorption to the central region 111a of the substrate W is released. Then, the lifter raises the substrate W from the central region 111a to a predetermined height and delivers it to the transfer device. The transfer device moves parallel to the substrate support unit 11 inside the chamber 10 while holding the substrate W, and unloads the substrate W from the chamber 10.

[0064] In one embodiment, steps ST1 to ST3 may be respectively executed for a plurality of substrates W. That is, steps ST1 to ST3 may be continuously repeated a plurality of times.

[0065] (Steps ST4 and ST5: Waferless cleaning) Process ST4 and process ST5 are part of the process of cleaning the inside of chamber 10. In one embodiment, process ST4 may be executed before process ST5. In one embodiment, process ST4 may be executed during process ST5. In one embodiment, process ST4 may be executed simultaneously with process ST5. In one embodiment, part or all of the period during which process ST4 is executed and the period during which process ST5 is executed may overlap.

[0066] Processes ST4 and ST5 are cleaning processes in chamber 10 that are executed with the substrate W not placed on substrate support 11, and are sometimes referred to as "waferless cleaning."

[0067] In waferless cleaning, since the substrate support 11 is exposed to plasma, it is easy to remove the deposits adhering to the substrate support 11. On the other hand, since the substrate support 11 is exposed to plasma, if the plasma density is increased excessively, the ion flux in the plasma increases and the substrate support 11 is damaged. Therefore, waferless cleaning is often performed at a relatively low plasma density, and conventionally, the processing time has tended to be long.

[0068] In contrast, in this processing method, the radical flux distribution of the plasma generated in chamber 10 is controlled, thereby enhancing the cleaning in the chamber. This will be described below.

[0069] (Process ST4) In process ST4, temperature control of the substrate support 11 is executed. The temperature control in process ST4 includes setting the temperature of the ring assembly 112 to a temperature different from the temperature of the central region 111a of the electrostatic chuck 1111 (hereinafter also referred to as "this temperature control"). The ring assembly 112 and the central region 111a are surfaces exposed to the plasma generated in the chamber, and the radical flux distribution of the plasma generated in chamber 10 changes due to this temperature control.

[0070] In one embodiment, the temperature of the ring assembly 112 may be set based on the distance D1 between the ring assembly 112 and the outer periphery of the central region 111a (the size of the gap between the ring assembly 112 and the central region 111a). In one embodiment, when the distance D1 is relatively small, for example, less than a threshold value DH1, the temperature of the ring assembly 112 may be set to a temperature lower than the temperature of the central region 111a. In one embodiment, when the distance D1 is relatively large, for example, greater than or equal to the threshold value DH1, the temperature of the ring assembly 112 may be set to a temperature higher than the temperature of the central region 111a.

[0071] In one embodiment, the temperature of the ring assembly 112 may be set based on the distance D2 from the deposits on the central region 111a (for example, the deposits DP shown in FIGS. 6 and 7). In one embodiment, when the distance D2 is relatively small, for example, less than a threshold value DH2, the temperature of the ring assembly 112 may be set to a temperature lower than the temperature of the central region 111a. In one embodiment, when the distance D2 is relatively large, for example, greater than or equal to the threshold value DH2, the temperature of the ring assembly 11 may be set to a temperature higher than the temperature of the central region 111a.

[0072] In one embodiment, the temperature of the ring assembly 112 may be set such that the temperature difference between the ring assembly 112 and the central region 111a is greater than the temperature difference in the process ST2. For example, consider the case where in the process ST2, the temperatures of the ring assembly 112 and the central region 111a are substantially the same and the temperature difference between the two is substantially zero. In this case, for example, the temperature of the ring assembly 112 may be set to a temperature higher than the temperature in the process ST2, and the temperature of the central region 111a may be set to the same temperature as or lower than the temperature in the process ST2. Also, for example, the temperature of the ring assembly 112 may be set to a temperature higher than the temperature in the process ST2, and the temperature of the central region 111a may be set to the same temperature as or higher than the temperature in the process ST2.

[0073] In one embodiment, this temperature control includes independently controlling the temperatures of the ring assembly 112 and the central region 111a to relatively change the temperature of the ring assembly 112 and the temperature of the central region 111a. This temperature control may be executed based on measured values such as the temperature of the control target (such as the ring assembly 112 and the central region 111a), or may also be executed based on measured values under the same or similar control conditions in the past or estimated values from the measured values.

[0074] In one embodiment, this temperature control may include controlling the flow rate or pressure of the heat transfer fluid (for example, helium gas) between the annular region 111b and the back surface of the ring assembly 112 by the control valve 530b. Thereby, the temperature of the ring assembly 112 is controlled independently of the central region 111a.

[0075] In one embodiment, this temperature control may include changing the adsorption force of the ring assembly 112 to the annular region 111b and the heat transfer rate between the two by controlling the voltage applied to the electrostatic electrodes 120a and 120b. Thereby, the temperature of the ring assembly 112 is controlled independently of the central region 111a.

[0076] In one embodiment, this temperature control may include changing the heat generation amount of the heater 55b by adjusting the power supplied from the heater power supply 57b to the heater 55b. Thereby, the temperature of the ring assembly 112 is controlled independently of the central region 111a.

[0077] In one embodiment, this temperature control may include changing the heat generation amount of the heater 55a by adjusting the power supplied from the heater power supply 57a to the heater 55a. Thereby, the temperature of the central region 111a is controlled independently of the ring assembly 112.

[0078] Note that this temperature control may include integrated control for simultaneously adjusting the temperatures of both the central region 111a and / or the ring assembly 112 in addition to independent control of the two. Examples of such integrated control include adjusting the temperature or flow rate of the heat transfer fluid flowing through the flow path 1110a of the base 1110.

[0079] (Step ST5: Generation of the second plasma) In one embodiment, the second plasma P2 may be generated as follows. That is, first, the gas supply unit 20 supplies a cleaning gas for generating the second plasma P2 into the plasma processing chamber 10. Then, the exhaust system 40 controls the pressure inside the chamber 10 to a predetermined set pressure. The set pressure may be higher than the set pressure inside the chamber 10 in step ST2.

[0080] The cleaning gas may be appropriately selected according to the deposits (e.g., deposits DP in FIGS. 6 and 7) adhering to the inside of the chamber 10. For example, when the deposit is a CF-based polymer, the cleaning gas may include a fluorine-containing gas such as NF3 or CF4. The cleaning gas may also include an oxygen-containing gas such as O2 gas, CO gas, CO2 gas, or O3 gas. Further, when silicon or metal is included in addition to the CF-based polymer as the deposit, the cleaning gas may include a halogen-containing gas. The halogen-containing gas may be, for example, a chlorine-based gas such as Cl2 gas or a bromine-based gas such as HBr gas.

[0081] Next, the first RF generation unit 31a supplies a source RF signal to the substrate support 11 or the shower head 13. Thereby, a high-frequency electric field is generated between the shower head 13 and the substrate support 11. Note that a bias signal may not be supplied to the lower electrode of the substrate support 11.

[0082] As described above, as shown in FIGS. 6 and 7, in the space defined by the central region 111a of the electrostatic chuck 111 and the shower head 13, the second plasma P2 is generated. The energy density of the second plasma P2 may be lower than the energy density of the first plasma P1. The deposits attached in the chamber 10 are removed by the second plasma P2.

[0083] FIG. 6 is an example in the case where the gap between the ring assembly 112 and the central region 111a is relatively small (the distance d1 between the two < threshold value DH1). In step ST4, the temperature of the ring assembly 112 is set to a temperature lower than the temperature of the central region 111a.

[0084] In FIG. 6, "RP" indicates the reaction probability between the radicals of the second plasma P2 and the deposits in the chamber 10 (hereinafter, also simply referred to as "reaction probability"). "Rp1" is the distribution of the reaction probability along the plasma exposure surface of the substrate support portion 11 when this temperature control is executed (when the temperature of the ring assembly 112 is set to a temperature lower than the temperature of the central region 111a). "Rp0" is the distribution of the reaction probability along the plasma exposure surface of the substrate support portion 11 when this temperature control is not executed (when the temperature of the ring assembly 112 is set to the same temperature as the temperature of the central region 111a).

[0085] Also in FIG. 6, "FL" indicates the radical flux in the second plasma P2. "FL1" is the distribution of the radical flux of the second plasma P2 along the plasma exposure surface of the substrate support portion 11 when this temperature control is executed. "FL0" is the distribution of the radical flux along the plasma exposure surface of the substrate support portion 11 when this temperature control is not executed.

[0086] As shown in FIG. 6, the reaction probability (Rp1) of the central region 111a when this temperature control is executed is the same as that when this temperature control is not executed (Rp0), including the outer peripheral positions (shoulders) P1 and P2. Since the reaction probability depends on the temperature at the location where the radicals react, it is considered that in this temperature control, the set temperature of the central region 111a has not changed. On the other hand, the radical flux (FL1) at the outer peripheral positions (shoulders) P1 and P2 when this temperature control is executed increases compared to when this temperature control is not executed (FL0). This is considered to be because the radicals in the plasma tend to move from the region with a higher temperature to the region with a lower temperature. That is, due to this temperature control, the radicals of the second plasma P2 generated on the central region 111a move toward the ring assembly 112 with a lower temperature, and it is considered that the distribution of the radical flux becomes larger toward the ring assembly 112. Note that the ions in the plasma are less affected by temperature compared to the radicals. Therefore, the distribution of the ion flux of the second plasma P2 does not change compared to when this temperature control is not executed.

[0087] As described above, in the example shown in FIG. 6, in step ST5, while the radical flux at the outer peripheral positions (shoulders) P1 and P2 increases compared to when this temperature control is not executed, the reaction probability does not change. Therefore, the reaction between the deposit DP at the outer peripheral positions (shoulders) P1 and P2 and the radicals of the second plasma P2 is promoted, and the removal of the deposit DP is promoted. Note that since the distribution of the ion flux in the second plasma does not change compared to when this temperature control is not executed, the damage to the substrate support portion 1 is suppressed.

[0088] FIG. 7 is an example in the case where the gap between the ring assembly 112 and the central region 111a is relatively large (the distance d2 between the two > threshold value DH1). In step ST4, the temperature of the ring assembly 112 is set to a temperature higher than the temperature of the central region 111a.

[0089] In FIG. 7, “RP” indicates the reaction probability between the radicals of the second plasma P2 and the deposits in the chamber 10. “Rp2” is the distribution of the reaction probability along the plasma-exposed surface of the substrate support 11 when this temperature control is executed (when the temperature of the ring assembly 112 is set to a temperature higher than the temperature of the central region 111a). “Rp0” is the distribution of the reaction probability along the plasma-exposed surface of the substrate support 11 when this temperature control is not executed (when the temperature of the ring assembly 112 is set to the same temperature as the temperature of the central region 111a).

[0090] Also in FIG. 7, “FL” indicates the radical flux in the second plasma P2. “FL2” is the distribution of the radical flux of the second plasma P2 along the plasma-exposed surface of the substrate support 11 when this temperature control is executed. “FL0” is the distribution of the radical flux along the plasma-exposed surface of the substrate support 11 when this temperature control is not executed.

[0091] As shown in FIG. 7, the reaction probability (Rp2) of the central region 111a when this temperature control is executed is the same as that when this temperature control is not executed (Rp0), including the outer peripheral positions (shoulders) P1 and P2. The reaction probability depends on the temperature of the location where the radicals react. In this temperature control, it is considered that this is because the set temperature of the central region 111a has not changed. On the other hand, the radical flux (FL2) at the outer peripheral positions (shoulders) P1 and P2 when this temperature control is executed increases compared to when this temperature control is not executed (FL0). This is considered to be because the radicals of the second plasma P2 generated on the central region 111a are less likely to move toward the ring assembly 112 with a higher temperature, and more radicals remain in the vicinity of the outer peripheral positions (shoulders) P1 and P2 of the central region 111a. Note that, unlike radicals, ions in the plasma are less affected by temperature. Therefore, the distribution of the ion flux of the second plasma P2 does not change compared to when this temperature control is not executed.

[0092] As described above, in the example shown in FIG. 7, in step ST5, the radical fluxes at the outer peripheral positions (shoulders) P1 and P2 increase compared to the case where this temperature control is not performed, while the reaction probability does not change. Therefore, the reaction between the deposit DP at the outer peripheral positions (shoulders) P1 and P2 and the radicals of the second plasma P2 is promoted, and the removal of the deposit DP is promoted. Note that since the distribution of the ion flux in the second plasma does not change compared to the case where this temperature control is not performed, damage to the substrate support portion 1 is also suppressed.

[0093] As described above, according to this processing method, the cleaning efficiency in the chamber 10 can be improved.

[0094] <Modification example> In this processing method, steps ST1 to ST3 may be processes for cleaning the inside of the chamber 10. In this case, the substrate W disposed in step ST1 may be a dummy substrate having no pattern formed on its surface. The dummy substrate may be, for example, a silicon substrate. Then, in step ST2, a cleaning gas may be supplied as a processing gas for generating the first plasma P1. In this case, part or all of the deposits attached to the inner wall of the chamber 10, the shower head 13, etc. in the previous plasma processing or the like are removed by the first plasma P1. The central region 111a of the electrostatic chuck 1111 is suppressed from being damaged by the first plasma P1 by the substrate W (dummy substrate). In this modification example, the deposit DP removed in step ST5 (waferless cleaning) may be a deposit that could not be completely removed in the cleaning of step ST2 or a deposit newly attached by the cleaning. Note that during part or all of the period of the cleaning in step ST2, the substrate W (dummy substrate) may be held at a position spaced apart from the central region 111a by a predetermined distance by a lifter and the cleaning may be performed (pin-up cleaning).

[0095] In this processing method, step ST5 may be executed before step ST4, and step ST4 may be executed after a certain period has elapsed. For example, at the start of step ST5, the temperature of the ring assembly 112 may be set to the same temperature as the temperature of the central region 111a. Then, after a certain period has elapsed, step ST4 may be executed to set the temperature of the ring assembly 112 to a temperature different from the temperature of the central region 111a.

[0096] Embodiments of the present disclosure further include the following aspects.

[0097] (Appendix 1) A plasma processing method executed in a plasma processing apparatus, The plasma processing apparatus includes a chamber, a substrate support portion disposed in the chamber, the substrate support portion including a first region configured to support a substrate, a second region surrounding the outer periphery of the first region, and an annular member supported on the second region, and is provided with The plasma processing method includes a step of cleaning the inside of the chamber in a state where no substrate is supported on the substrate support portion, The step (a) includes (a1) setting the temperature of the annular member to a temperature different from the temperature of the first region, (a2) generating plasma from a cleaning gas in the chamber, and includes Plasma processing method.

[0098] (Appendix 2) In the step (a1), the temperature of the annular member is set based on the distance between the annular member and the outer periphery of the first region. The plasma processing method according to Appendix 1.

[0099] (Appendix 3) In the step (a1), the temperature of the annular member is set to a temperature lower than the temperature of the first region. The plasma processing method according to Appendix 1 or Appendix 2.

[0100] (Supplementary Note 4) The plasma processing method according to Supplementary Note 1 or Supplementary Note 2, wherein in (a1), the temperature of the annular member is set to a temperature higher than the temperature of the first region.

[0101] (Supplementary Note 5) The plasma processing method further includes (b) a step of generating plasma from a processing gas in the chamber while a substrate is supported on the substrate support portion, The plasma processing method according to Supplementary Note 1, wherein in (a1), the temperatures of the annular member and the first region are set such that the temperature difference between the temperature of the annular member and the temperature of the first region is larger than the temperature difference in (b).

[0102] (Supplementary Note 6) The plasma processing method according to Supplementary Note 5, wherein in (a1), the temperature of the annular member is set to a temperature lower than the temperature of the annular member in (b).

[0103] (Supplementary Note 7) The plasma processing method according to Supplementary Note 5, wherein in (a1), the temperature of the annular member is set to a temperature higher than the temperature of the annular member in (b).

[0104] (Supplementary Note 8) The plasma processing method according to any one of Supplementary Notes 5 to 7, wherein in (a1), the temperature of the first region is set to a temperature higher than the temperature of the first region in (b).

[0105] (Supplementary Note 9) The plasma processing method according to any one of Supplementary Notes 5 to 7, wherein in (a1), the temperature of the first region is set to a temperature higher than the temperature of the first region in (b).

[0106] (Supplementary Note 10) In the above (b), the processing gas contains a reaction gas, and the substrate is etched by the plasma generated from the processing gas. The plasma processing method according to any one of Appendices 5 to 9.

[0107] (Appendix 11) In the above (b), the processing gas contains a cleaning gas, and the inside of the chamber is cleaned by the plasma generated from the processing gas. The plasma processing method according to any one of Appendices 5 to 9.

[0108] (Appendix 12) The above (a) is executed after the above (b). In the above (a1), based on the distance between the deposit attached to the first region and the annular member, the temperature of the annular member is set. The plasma processing method according to any one of Appendices 5 to 11.

[0109] (Appendix 13) At least a part of the period of executing the above (a1) and the period of executing the above (a2) overlap. The plasma processing method according to any one of Appendices 1 to 12.

[0110] (Appendix 14) The above (a1) and the above (a2) are executed simultaneously. The plasma processing method according to any one of Appendices 1 to 13.

[0111] (Appendix 15) The plasma processing apparatus is provided with a recess configured such that a heat transfer fluid is supplied between the annular member and the second region. In the above (a1), the temperature of the annular member is controlled by adjusting the pressure of the heat transfer fluid supplied to the recess. The plasma processing method according to any one of Appendices 1 to 14.

[0112] (Appendix 16) The plasma processing apparatus A first chuck electrode provided below the first region, A second chuck electrode provided below the second region and controllable independently of the first chuck electrode, further comprising, In the above (a1), the temperature of the annular member is controlled by adjusting the voltage applied to the second chuck electrode, and the plasma processing method according to any one of Appendices 1 to 15.

[0113] (Appendix 17) The plasma processing apparatus, A first heater provided below the first region, A second heater provided below the second region and controllable independently of the first heater, comprising, In the above (a1), the temperature of the annular member is controlled by adjusting the power supplied to the second heater, and the plasma processing method according to any one of Appendices 1 to 16.

[0114] (Appendix 18) A plasma processing apparatus, A chamber, A substrate support portion disposed in the chamber, including a first region configured to support a substrate, a second region surrounding the outer periphery of the first region, and an annular member supported on the second region, A control unit, The control unit is configured to execute control for cleaning the inside of the chamber in a state where no substrate is supported on the substrate support portion, The above (a) is, (a1) Setting the temperature of the annular member to a temperature different from the temperature of the first region, (a2) Generating plasma from a cleaning gas in the chamber, including, A plasma processing apparatus.

[0115] Each of the above embodiments has been described for the purpose of explanation and is not intended to limit the scope of the present disclosure. Each of the above embodiments can be variously modified without departing from the scope and spirit of the present disclosure. For example, some components in one embodiment can be added to another embodiment. Also, some components in one embodiment can be replaced with corresponding components in another embodiment.

Description of Reference Numerals

[0116] 1... Plasma processing apparatus, 2... Control unit, 10... Plasma processing chamber, 11... Substrate support unit, 1111... Electrostatic chuck, 111a... Central region, 111b... Annular region, 112... Ring assembly

Claims

1. A plasma processing method executed in a plasma processing apparatus, The plasma processing apparatus includes: a chamber, a substrate support portion disposed in the chamber, the substrate support portion including a first region configured to support a substrate, a second region surrounding an outer periphery of the first region, and an annular member supported on the second region, and is provided with The plasma processing method includes a step of cleaning the inside of the chamber in a state where no substrate is supported on the substrate support portion, The step (a) includes: (a1) setting the temperature of the annular member to a temperature different from the temperature of the first region, (a2) generating plasma from a cleaning gas in the chamber, and includes Plasma processing method.

2. The plasma processing method according to claim 1, wherein in the step (a1), the temperature of the annular member is set based on a distance between the annular member and the outer periphery of the first region.

3. The plasma processing method according to claim 1, wherein in the step (a1), the temperature of the annular member is set to a temperature lower than the temperature of the first region.

4. The plasma processing method according to claim 1, wherein in the step (a1), the temperature of the annular member is set to a temperature higher than the temperature of the first region.

5. The plasma processing method further includes: (b) generating plasma from a processing gas in the chamber in a state where a substrate is supported on the substrate support portion, The plasma processing method according to claim 1, wherein in the step (a1), the temperatures of the annular member and the first region are set such that a temperature difference between the temperature of the annular member and the temperature of the first region is larger than the temperature difference in the step (b).

6. The plasma processing method according to claim 5, wherein in (a1), the temperature of the annular member is set to a temperature lower than the temperature of the annular member in (b).

7. The plasma processing method according to claim 5, wherein in (a1), the temperature of the annular member is set to a temperature higher than the temperature of the annular member in (b).

8. The plasma processing method according to claim 5, wherein in (a1), the temperature of the first region is set to a temperature higher than the temperature of the first region in (b).

9. The plasma processing method according to claim 5, wherein in (a1), the temperature of the first region is set to a temperature higher than the temperature of the first region in (b).

10. The plasma processing method according to claim 5, wherein in (b), the processing gas contains a reaction gas, and the substrate is etched by the plasma generated from the processing gas.

11. The plasma processing method according to claim 5, wherein in (b), the processing gas contains a cleaning gas, and the inside of the chamber is cleaned by the plasma generated from the processing gas.

12. (a) is executed after (b), The plasma processing method according to claim 5, wherein in (a1), the temperature of the annular member is set based on the distance between the deposit attached to the first region and the annular member.

13. The plasma processing method according to any one of claims 1 to 12, wherein at least a part of the period of executing (a1) and the period of executing (a2) overlap.

14. The plasma processing method according to any one of claims 1 to 12, wherein (a1) and (a2) are executed simultaneously.

15. The plasma processing apparatus is provided with a recess configured such that a heat transfer fluid is supplied between the annular member and the second region. In the above (a1), the temperature of the annular member is controlled by adjusting the pressure of the heat transfer fluid supplied to the recess. The plasma processing method according to any one of claims 1 to 12.

16. The plasma processing apparatus includes a first chuck electrode provided below the first region, and a second chuck electrode provided below the second region and controllable independently of the first chuck electrode. Further comprising In the above (a1), the temperature of the annular member is controlled by adjusting the voltage applied to the second chuck electrode. The plasma processing method according to any one of claims 1 to 12.

17. The plasma processing apparatus includes a first heater provided below the first region, and a second heater provided below the second region and controllable independently of the first heater. Comprising In the above (a1), the temperature of the annular member is controlled by adjusting the power supplied to the second heater. The plasma processing method according to any one of claims 1 to 12.

18. A plasma processing apparatus, comprising a chamber, a substrate support portion disposed in the chamber, the substrate support portion including a first region configured to support a substrate, a second region surrounding the outer periphery of the first region, and an annular member supported on the second region, and a control unit. The control unit is configured to execute control for cleaning the inside of the chamber in a state where no substrate is supported on the substrate support portion. The above (a) is (a1) setting the temperature of the annular member to a temperature different from the temperature of the first region; (a2) generating plasma from a cleaning gas in the chamber; including a plasma processing apparatus.

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