Substrate processing method and plasma processing apparatus

Abstract

To provide a technique for cleaning a dummy substrate to be used for seasoning.SOLUTION: A substrate processing method in a plasma processing apparatus is provided. The plasma processing apparatus includes a chamber and a substrate support section which is provided in the chamber and has a mounting area on which a substrate is placed. The substrate processing method includes a step (a) of performing seasoning using a dummy substrate, and a step (b) of cleaning the inside of the chamber. The step (b) includes a step (b1) for holding the dummy substrate at a position spaced apart from the mounting area so as to face the mounting area, and a step (b2) for generating a second plasma from a second processing gas in the chamber in a state where the dummy substrate is held at the spaced position and cleaning at least an area including the periphery of the mounting area and the dummy substrate.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] Exemplary embodiments of the present disclosure relate to an etching method and a plasma processing system. [Background technology]

[0002] Patent Document 1 discloses a technique for cleaning a mounting table in a plasma processing apparatus. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2022 / 249964 Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides a technique for cleaning a dummy substrate used for seasoning. [Means for solving the problem]

[0005] In one exemplary embodiment of the present disclosure, there is provided a substrate processing method in a plasma processing apparatus, the plasma processing apparatus including a chamber and a substrate support section provided in the chamber and having a mounting area on which a substrate is placed, the substrate processing method including the steps of: (a) performing seasoning using a dummy substrate, the step including: (a1) placing the dummy substrate in the mounting area; and (a2) generating a first plasma from a first process gas containing carbon and fluorine in the chamber while the dummy substrate is placed in the mounting area; and (b) cleaning the inside of the chamber, the step including: (b1) holding the dummy substrate at a position spaced apart from the mounting area so as to face the mounting area; and (b2) generating a second plasma from a second process gas in the chamber while the dummy substrate is held at the spaced apart position to clean at least an area including a periphery of the mounting area and the dummy substrate. Effect of the Invention

[0006] According to one exemplary embodiment of the present disclosure, a technique for cleaning a dummy substrate used for seasoning can be provided. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram for explaining a configuration example of a plasma processing system. [Diagram 2] FIG. 1 is a diagram for explaining a configuration example of a capacitively coupled plasma processing apparatus. [Diagram 3] 4 is a flowchart illustrating an example of the present processing method. [Figure 4] 13 is a flowchart showing an example of a step ST1. [Diagram 5] FIG. 2 is a diagram illustrating the inside of the chamber 10 in step ST12. [Figure 6] 13 is a flowchart showing an example of a step ST2. [Figure 7] FIG. 2 is a diagram illustrating the inside of the chamber 10 in step ST22. [Figure 8] FIG. 2 is a diagram illustrating the inside of the chamber 10 in step ST24. [Figure 9] 13 is a flowchart showing another example of the step ST2. [Figure 10] 13 is a flowchart showing another example of the step ST2. [Figure 11] 13 is a flowchart showing another example of the step ST2. [Figure 12] FIG. 2 is a diagram showing a schematic view of the inside of the chamber 10 in step ST4. [Figure 13] 13 is a flowchart showing an example of a step ST5. [Figure 14] 1 is a diagram showing an example of a cross-sectional structure of a patterned substrate PW. [Figure 15] FIG. 13 is a diagram illustrating the inside of the chamber 10 in step ST52. [Figure 16] 1 is a diagram showing a modified example of the substrate support part 11 of the plasma processing apparatus 1. FIG. [Figure 17] 1 is a diagram showing a modified example of the substrate support part 11 of the plasma processing apparatus 1. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Each embodiment of the present disclosure will be described below.

[0009] In one exemplary embodiment, there is provided a substrate processing method in a plasma processing apparatus, the plasma processing apparatus including a chamber and a substrate support section provided within the chamber and having a mounting area on which a substrate is placed, the substrate processing method including the steps of: (a) performing seasoning using a dummy substrate, the step including: (a1) placing the dummy substrate in the mounting area; and (a2) generating a first plasma from a first process gas containing carbon and fluorine in the chamber while the dummy substrate is placed in the mounting area; and (b) cleaning the inside of the chamber, the step including: (b1) holding the dummy substrate at a position spaced apart from the mounting area so as to face the mounting area; and (b2) generating a second plasma from a second process gas in the chamber while the dummy substrate is held at the spaced apart position to clean at least an area including a periphery of the mounting area and the dummy substrate.

[0010] In one exemplary embodiment, (b) further includes (b3) generating a third plasma from a third process gas in the chamber with the dummy substrate disposed in the mounting area to clean at least the dummy substrate.

[0011] In one exemplary embodiment, (b3) is performed after (b2).

[0012] In one exemplary embodiment, (b3) is performed before (b1).

[0013] In one exemplary embodiment, (b3) is performed before (b1) and after (b2), respectively.

[0014] In one exemplary embodiment, the second process gas comprises an oxygen-containing gas and / or a fluorine-containing gas.

[0015] In one exemplary embodiment, the spaced apart location is between 0.01 mm and 1 mm from the mounting area.

[0016] In one exemplary embodiment, the third process gas comprises an oxygen-containing gas and / or a fluorine-containing gas.

[0017] In one exemplary embodiment, after (b), the method further includes the steps of (c) removing the dummy substrate from the chamber, and (d) loading the substrate into the chamber and plasma processing the substrate in the chamber using a first plasma generated from a first processing gas.

[0018] In one exemplary embodiment, after (d), the method further includes the steps of (f) removing the substrate from the chamber, and (g) loading a dummy substrate into the chamber and performing (b) again.

[0019] In one exemplary embodiment, during at least one of the periods between (c) and (d) and (f) and (g), the method further includes the step of (h) generating a fourth plasma from a fourth process gas in the chamber while the substrate and the dummy substrate are not placed in the mounting region, to clean at least an area including the mounting region.

[0020] In one exemplary embodiment, the fourth process gas comprises an oxygen-containing gas and / or a fluorine-containing gas.

[0021] In one exemplary embodiment, the fourth process gas comprises an inert gas.

[0022] In one exemplary embodiment, there is provided a plasma processing apparatus comprising: a chamber; a substrate support section provided within the chamber and having a mounting area on which a substrate is placed; and a controller, wherein the controller is configured to execute: (a) control for seasoning using a dummy substrate, the control section including: (a1) placing the dummy substrate in the mounting area; and (a2) generating a first plasma from a first process gas containing carbon and fluorine in the chamber while the dummy substrate is placed in the mounting area; and (b) control for cleaning the dummy substrate, the control section including: (b1) holding the dummy substrate at a position spaced apart from the mounting area so as to face the mounting area; and (b2) generating a second plasma from a second process gas in the chamber while the dummy substrate is held at the spaced apart position to clean at least an area including a periphery of the mounting area and the dummy substrate.

[0023] Hereinafter, each embodiment of the present disclosure will be described in detail with reference to the drawings. In each drawing, the same or similar elements are given the same reference numerals, and duplicated explanations will be omitted. Unless otherwise specified, the positional relationship such as up, down, left, right, etc. will be described based on the positional relationship shown in the drawing. The dimensional ratio of the drawings does not indicate the actual ratio, and the actual ratio is not limited to the illustrated ratio.

[0024] <Example of plasma processing system configuration> 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 device 1 and a control unit 2. The plasma processing system is an example of a substrate processing system, and the plasma processing device 1 is an example of a substrate processing device. The plasma processing device 1 includes a plasma processing chamber 10, a substrate support unit 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 exhaust port for exhausting gas from the plasma processing space. The gas supply port is connected to a gas supply unit 20 described later, and the gas exhaust port is connected to an exhaust system 40 described later. The substrate support unit 11 is disposed in the plasma processing space, and has a substrate support surface for supporting a substrate.

[0025] The plasma generating unit 12 is configured to generate plasma from at least one processing gas supplied into the plasma processing space. The plasma formed in the plasma processing space may be a capacitively coupled plasma (CCP), an inductively coupled plasma (ICP), an electron-cyclotron-resonance plasma (ECR plasma), a helicon wave plasma (HWP), a surface wave plasma (SWP), or the like. Also, various types of plasma generating units may be used, including an alternating current (AC) plasma generating unit and a direct current (DC) plasma generating unit. In one embodiment, the AC signal (AC power) used in the AC plasma generating unit has a frequency in the range of 100 kHz to 10 GHz. Thus, 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.

[0026] The control unit 2 processes computer-executable instructions that cause the plasma processing apparatus 1 to execute various steps described in the present disclosure. The control unit 2 may be configured to control each element of the plasma processing apparatus 1 to execute various steps described herein. In one embodiment, a 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, for example, by a computer 2a. The processing unit 2a1 may 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 is 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 random access memory (RAM), a read only memory (ROM), a hard disk drive (HDD), a solid state drive (SSD), or a combination thereof. The communication interface 2a3 may communicate with the plasma processing apparatus 1 via a communication line such as a local area network (LAN).

[0027] The following describes a configuration example of a capacitively coupled plasma processing apparatus as an example of the plasma processing apparatus 1. Fig. 2 is a diagram for explaining the configuration example of a capacitively coupled plasma processing apparatus.

[0028] The capacitively coupled plasma processing apparatus 1 includes a plasma processing chamber 10, a gas supply 20, a power supply 30, and an exhaust system 40. The plasma processing apparatus 1 also includes a substrate support 11 and a gas inlet. The gas inlet is configured to introduce at least one processing gas into the plasma processing chamber 10. The gas inlet includes a showerhead 13. The substrate support 11 is disposed in the plasma processing chamber 10. The showerhead 13 is disposed above the substrate support 11. In one embodiment, the showerhead 13 forms at least a part of a ceiling of the plasma processing chamber 10. The plasma processing chamber 10 has a plasma processing space 10s defined by the showerhead 13, a sidewall 10a of the plasma processing chamber 10, and the substrate support 11. The plasma processing chamber 10 is grounded. The showerhead 13 and the substrate support 11 are electrically insulated from a housing of the plasma processing chamber 10.

[0029] The substrate support 11 includes a main body 111 and a ring assembly 112. The main body 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 111 surrounds the central region 111a of the main body 111 in a plan view. The substrate W is disposed on the central region 111a of the main body 111, and the ring assembly 112 is disposed on the annular region 111b of the main body 111 so as to surround the substrate W on the central region 111a of the main body 111. Therefore, the central region 111a is also called a substrate support surface for supporting the substrate W, and the annular region 111b is also called a ring support surface for supporting the ring assembly 112.

[0030] In one embodiment, the main body 111 includes a base 1110 and an electrostatic chuck 1111. The base 1110 includes a conductive member. The conductive member of the base 1110 may 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 source 31 and / or a DC power source 32 described later may be disposed in 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 described later is supplied to the at least one RF / DC electrode, the RF / DC electrode is also called a bias electrode. Note that the conductive member of the base 1110 and the at least one RF / DC electrode may function as multiple lower electrodes. Also, the electrostatic electrode 1111b may function as a lower electrode. Thus, the substrate support 11 includes at least one lower electrode.

[0031] 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.

[0032] The substrate support 11 may also include a temperature adjustment 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 adjustment module may include a heater, a heat transfer medium, a flow passage 1110a, or a combination thereof. A heat transfer fluid such as a brine or a gas flows through the flow passage 1110a. In one embodiment, the flow passage 1110a is formed in the base 1110, and one or more heaters are disposed in the ceramic member 1111a of the electrostatic chuck 1111. The substrate support 11 may also include a heat transfer gas supply configured to supply a heat transfer gas to a gap between the back surface of the substrate W and the central region 111a.

[0033] The substrate support 11 is provided with a plurality of, for example, three, pin through holes. A lifter LF is provided inside each of these pin through holes (see FIGS. 5 and 7). The lifter LF is connected to an actuator. The actuator can raise or lower the lifter LF to cause the lifter LF to protrude from the central region 111a of the substrate support 11. When the lifter LF is raised with the substrate W disposed in the central region 111a of the substrate support 11, the tip of the lifter LF protrudes from the central region 111a, and the substrate W is held at a predetermined distance from the central region 111a (see FIG. 7). On the other hand, when the lifter LF is lowered, the tip of the lifter LF is accommodated in the pin through hole, and the substrate W is disposed in the central region 111a of the substrate support 11 (see FIG. 5). In this manner, the actuator can control the position of the substrate W relative to the central region 111a of the substrate support 11 (the position in the direction perpendicular to the central region 111a) by means of the lifter LF.

[0034] The shower head 13 is configured to introduce at least one processing 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 multiple gas inlets 13c. The processing gas supplied to the gas supply port 13a passes through the gas diffusion chamber 13b and is introduced into the plasma processing space 10s from the multiple gas inlets 13c. The shower head 13 also includes at least one upper electrode. Note that the gas introduction unit may include, in addition to the shower head 13, one or more side gas injectors (SGIs) attached to one or more openings formed in the sidewall 10a.

[0035] The gas supply 20 may include at least one gas source 21 and at least one flow controller 22. In one embodiment, the gas supply 20 is configured to supply at least one process gas from a respective gas source 21 through a respective flow controller 22 to the showerhead 13. Each flow controller 22 may include, for example, a mass flow controller or a pressure-controlled flow controller. Additionally, the gas supply 20 may include at least one flow modulation device to modulate or pulse a flow rate of the at least one process gas.

[0036] The power source 30 includes an RF power source 31 coupled to the plasma processing chamber 10 via at least one impedance matching circuit. The RF power source 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. This causes a plasma to be formed from at least one processing gas supplied to the plasma processing space 10s. Thus, the RF power source 31 can function as at least a part of the plasma generating unit 12. In addition, by supplying a bias RF signal to the at least one lower electrode, a bias potential is generated on the substrate W, and ion components in the formed plasma can be attracted to the substrate W.

[0037] In one embodiment, the RF power supply 31 includes a first RF generating unit 31a and a second RF generating unit 31b. The first RF generating 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 generating 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.

[0038] The second RF generating unit 31b is coupled to at least one lower electrode via at least one impedance matching circuit and 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 generating 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.

[0039] The power supply 30 may also include a DC power supply 32 coupled to the plasma processing chamber 10. The DC power supply 32 includes a first DC generator 32a and a second DC generator 32b. In one embodiment, the first DC generator 32a is connected to at least one lower electrode and configured to generate a first DC signal. The generated first DC signal is applied to the at least one lower electrode. In one embodiment, the second DC generator 32b is connected to at least one upper electrode and configured to generate a second DC signal. The generated second DC signal is applied to the at least one upper electrode.

[0040] 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 rectangular, trapezoidal, triangular or combination of these pulse waveforms. In one embodiment, a waveform generator for generating a sequence of voltage pulses from the DC signal is connected between the first DC generator 32a and at least one lower electrode. Thus, the first DC generator 32a and the waveform generator constitute a voltage pulse generator. When the second DC generator 32b and the waveform generator constitute a voltage pulse generator, the voltage pulse generator 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 in one period. The first and second DC generating units 32a, 32b may be provided in addition to the RF power supply 31, or the first DC generating unit 32a may be provided in place of the second RF generating unit 31b.

[0041] The exhaust system 40 may be connected to, for example, a gas exhaust port 10e provided at the bottom of the plasma processing chamber 10. The exhaust system 40 may include a pressure regulating valve and a vacuum pump. The pressure in the plasma processing space 10s is adjusted by the pressure regulating valve. The vacuum pump may include a turbomolecular pump, a dry pump, or a combination thereof.

[0042] <Seasoning> It is known that seasoning is performed for the purpose of adjusting the inside of a plasma processing chamber (hereinafter also referred to as "chamber") to a state similar to a steady state in which plasma processing is performed stably and continuously. Seasoning is performed, for example, when the plasma processing apparatus is in operation, at intervals, or when restarting after maintenance. Seasoning is often performed by using a dummy substrate to create conditions similar to those of actual plasma processing.

[0043] The dummy substrate for seasoning is highly contaminated by seasoning, so there is a limit to its repeated use. It is also difficult to use the dummy substrate for seasoning in other substrate processing processes. For example, the dummy substrate for seasoning is highly contaminated, so it cannot be used as a dummy substrate for cleaning the inside of a chamber. Therefore, it was necessary to prepare a dummy substrate for seasoning and a dummy substrate for cleaning the inside of a chamber separately.

[0044] A substrate processing method according to one exemplary embodiment (hereinafter also referred to as "this processing method") provides a technique for cleaning a dummy substrate used for seasoning.

[0045] <An example of a substrate processing method> 3 is a flow chart showing an example of the present processing method. The present processing method includes a step of performing seasoning using a dummy substrate (ST1), a step of cleaning the inside of a chamber (ST2), a step of unloading the dummy substrate (ST3), a step of performing waferless cleaning (ST4), a step of performing plasma processing on a patterned substrate (ST5), a step of performing waferless cleaning (ST6), a step of loading the dummy substrate (ST7), a step of cleaning the inside of a chamber (ST8), and a step of determining a stop condition (ST9).

[0046] In addition, in this processing method, all the steps shown in Fig. 3 are not essential. That is, some of the steps shown in Fig. 3 may be omitted. For example, either or both of step ST4 and step ST6 may be omitted. Hereinafter, an example of the processing in each step shown in Fig. 3 will be described with reference to each figure.

[0047] The processes in the steps shown in Fig. 3 may be performed by the plasma processing apparatus 1 shown in Fig. 1 or 2. In the following, an example will be described in which the control unit 2 controls each part of the plasma processing apparatus 1 shown in Fig. 2 to perform this processing method.

[0048] (Step ST1: Seasoning) In step ST1, seasoning is performed using a dummy substrate DW. The dummy substrate DW is a substrate that does not have a layer with a pattern formed on its surface, such as a silicon substrate. In one embodiment, seasoning may be performed by using the dummy substrate DW to create conditions similar to those of the plasma processing in step ST5 (e.g., etching on the patterned substrate PW). That is, seasoning may be a process that adjusts the state inside the chamber 10 to a steady state (the state of the chamber 10 during the plasma processing in step ST5). The seasoning in step ST1 may be performed when the plasma processing apparatus 1 is in operation, or when it is restarted after an interval or maintenance.

[0049] Fig. 4 is a flow chart showing an example of step ST1. In one embodiment, step ST1 includes step ST11 of arranging a dummy substrate and step ST12 of generating a first plasma. Fig. 5 is a diagram showing a schematic view of the inside of the chamber 10 in step ST12.

[0050] In step ST11, first, the dummy substrate DW is loaded into the chamber 10 of the plasma processing apparatus 1. Specifically, the dummy substrate DW is disposed at the tip of the lifter LF in a state in which the lifter LF protrudes from a central region 111a (hereinafter also referred to as a "mounting region") of the electrostatic chuck 1111. Then, the lifter LF is lowered to place the dummy substrate DW in the mounting region (see FIG. 5). Then, when a predetermined voltage is applied to the electrodes of the electrostatic chuck 1111, the dummy substrate DW is electrostatically attracted to the mounting region.

[0051] In step ST12, a first plasma is generated in the chamber 10. The first plasma may be generated under the same conditions as in step ST5, which will be described later, for performing plasma processing on a patterned substrate. Specifically, first, a first processing gas is supplied from the gas supply unit 20 into the chamber 10. At this time, the pressure in the chamber 10 may be set to be the same as the pressure in the plasma processing in step ST5. The first processing gas contains carbon and fluorine. In one embodiment, the first processing gas may contain a fluorocarbon gas or a hydrofluorocarbon gas. In one embodiment, the first processing gas may contain various other gases, such as a metal-containing gas, a halogen-containing gas other than fluorine, and an oxygen-containing gas.

[0052] Next, a source RF signal is supplied to the lower electrode of the substrate support 11 and / or the upper electrode of the showerhead 13. This generates a high frequency electric field between the showerhead 13 and the substrate support 11. In one embodiment, a bias signal may be supplied to the lower electrode of the substrate support 11.

[0053] As a result, as shown in FIG. 5, a first plasma P1 is generated in a space defined by the dummy substrate DW disposed in the placement area and the shower head 13 functioning as an upper electrode. When a bias signal is supplied, a bias potential is generated between the first plasma P1 and the dummy substrate DW. The bias potential attracts active species such as ions and radicals in the first plasma P1 to the dummy substrate DW. Step ST12 is performed until the state in the chamber 10 becomes stable. At the end of step ST12, deposits (in one example, CF-based polymers) originating from the first plasma P1 adhere to, for example, the surface of the dummy substrate DW and the periphery of the placement area (including the shoulder portion 111e of the electrostatic chuck 1111).

[0054] (Step ST2: Cleaning inside the chamber) In step ST2, the inside of the chamber 10 is cleaned. Step ST2 may be performed consecutively from step ST1.

[0055] Fig. 6 is a flow chart showing an example of step ST2. In one embodiment, step ST2 includes step ST21 of lifting a dummy substrate, step ST22 of generating a second plasma, step ST23 of lowering the dummy substrate, and step ST24 of generating a third plasma. Fig. 7 is a diagram showing a schematic view of the inside of the chamber 10 in step ST22. Fig. 8 is a diagram showing a schematic view of the inside of the chamber 10 in step ST24.

[0056] In step ST21, the dummy substrate DW is lifted by the lifter LF. Specifically, as shown in Fig. 7, the lifter LF is moved in a direction toward the shower head 13 so that the tip of the lifter LF protrudes from the central region 111a (mounting region) of the electrostatic chuck 1111. As a result, the lifter LF lifts the dummy substrate DW from the mounting region, and the dummy substrate DW is held at a position at a predetermined distance d from the mounting region. The dummy substrate DW may be held parallel to the mounting region.

[0057] The distance d between the dummy substrate DW and the central region 111a (mounting region) of the electrostatic chuck 1111 may be, for example, a distance at which plasma is not generated between the dummy substrate DW and the mounting region in step 22 described below. The distance d may be, for example, 0.01 mm or more and 1 mm or less. The distance d may also be 0.2 mm or more and 0.7 mm or less.

[0058] In step ST22, a second plasma is generated in the chamber 10. Specifically, first, a second processing gas is supplied from the gas supply unit 20 into the chamber 10. The pressure in the chamber 10 may be set to a pressure higher than that in step ST1. The second processing gas may be appropriately selected according to the deposits attached to the surface of the dummy substrate DW. For example, when the deposits are CF-based polymers, the second processing gas may contain a fluorine-containing gas such as NF3 or CF4. The second processing gas may contain O2 gas. The second processing gas may contain other oxygen-containing gases such as CO gas, CO2 gas, and O3 gas, not limited to O2 gas. When the deposits include silicon or metal in addition to the CF-based polymer, the second processing gas may contain a halogen-containing gas. The halogen-containing gas may be a chlorine-based gas such as Cl2 gas, or a bromine-based gas such as HBr gas.

[0059] Next, a source RF signal is supplied to the lower electrode of the substrate support 11 and / or the upper electrode of the shower head 13. This generates a high-frequency electric field between the shower head 13 and the substrate support 11. Note that a bias signal does not need to be supplied to the lower electrode of the substrate support 11.

[0060] As a result, as shown in FIG. 7, a second plasma P2 is generated in a space defined by the dummy substrate DW held at a position at a predetermined distance d from the placement region and the shower head 13 functioning as an upper electrode. The inside of the chamber 10 is cleaned by the second plasma P2. The second plasma P2 removes part or all of the deposits attached to the dummy substrate DW. As shown in FIG. 7, the second plasma P2 may diffuse between the dummy substrate DW and the electrostatic chuck 1111. This makes it possible to remove part or all of the deposits attached to the shoulder 111e (around the placement region) of the electrostatic chuck 1111 while suppressing damage to the central region 111a (placement region) of the electrostatic chuck 1111 by the plasma. The second plasma may remove part or all of the deposits attached to the inner wall of the chamber 10 and other components (for example, the shower head 13 and the ring assembly 112).

[0061] In step ST23, the dummy substrate DW is lowered by the lifter LF. As the lifter LF is lowered, the dummy substrate DW is disposed in the central region 111a (mounting region) (see FIG. 8). Then, when a predetermined voltage is applied to the electrode of the electrostatic chuck 1111, the dummy substrate DW is electrostatically attracted to the mounting region.

[0062] In step ST24, a third plasma P3 is generated in the chamber 10. Specifically, first, a third process gas is supplied from the gas supply unit 20 into the chamber 10. The pressure in the chamber 10 may be set to a pressure lower than that in step ST22. The third process gas may be appropriately selected depending on the deposits attached to the surface of the dummy substrate DW. The third process gas may contain the same gas as the second process gas.

[0063] Next, a source RF signal is supplied to the lower electrode of the substrate support 11 and / or the upper electrode of the showerhead 13. This generates a high-frequency electric field between the showerhead 13 and the substrate support 11. At this time, a bias signal may or may not be supplied to the lower electrode of the substrate support 11.

[0064] As a result, as shown in FIG. 8, a third plasma P3 is generated in a space defined by the dummy substrate DW placed in the placement area and the shower head 13 functioning as an upper electrode. The energy density of the third plasma P3 may be higher than that of the second plasma P2. The third plasma P3 cleans the inside of the chamber 10. At this time, the central area 111a (placement area) of the electrostatic chuck 1111 is prevented from being damaged by the plasma because the dummy substrate DW is placed therein. The third plasma P3 removes part or all of the deposits attached to the dummy substrate DW. The third plasma P3 may remove part or all of the deposits attached to the inner wall of the chamber 10 and other components (e.g., the shower head 13 and the ring assembly 112).

[0065] 9 to 11 are flow charts showing other examples of step ST2. As shown in FIG. 9, in step ST2, only cleaning by steps ST21 and ST22 (hereinafter also referred to as "pin-up cleaning") is performed, and steps ST23 and ST24 may not be performed. Also, as shown in FIG. 10, in step ST2, cleaning using the third plasma P3 by step ST24 may be performed before the pin-up cleaning. Also, as shown in FIG. 11, cleaning using the third plasma P3 by step ST24 may be performed before and after step ST2.

[0066] In the examples shown in FIG. 9 and FIG. 10, step ST2 is completed by pin-up cleaning. In the pin-up cleaning, the dummy substrate DW is held at a position separated from the electrostatic chuck 1111, so that it is difficult to release heat from the second plasma P2, and the substrate temperature may become higher than when the dummy substrate DW is in contact with the electrostatic chuck 1111. Therefore, a cooling step for lowering the substrate temperature may be provided before proceeding to the next step ST3. In the cooling step, the dummy substrate DW may be held at a position separated from the electrostatic chuck 1111 for a certain period of time, or may be placed in the central region 111a (mounting region) in the same manner as in step ST23. In the examples shown in FIG. 6 and FIG. 11, step ST2 is completed at step ST24 (i.e., the dummy substrate DW is in contact with the electrostatic chuck 1111), so the cooling step may not be performed.

[0067] (Step ST3: Removal of dummy substrate) In step ST3, the dummy substrate DW is carried out of the chamber 10. The dummy substrate DW may be transported from the chamber 10 to the outside by a transport device and stored in an external accommodation chamber (e.g., a FOUP). The stored dummy substrate DW may be carried back into the chamber 10 in step ST7, which will be described later, and used as a dummy substrate DW for cleaning in step ST8.

[0068] (Process ST4: Waferless cleaning) In step ST4, waferless cleaning is performed. Waferless cleaning is cleaning within the chamber 10 performed in a state where a substrate (including a dummy substrate DW or a patterned substrate PW) is not placed on the substrate support 11. That is, waferless cleaning is performed in a state where the central region 111a is exposed to the shower head 13. Note that step ST4 is not essential and may be performed as appropriate depending on the state of contamination of components within the chamber 10, the continuous use time of the plasma processing apparatus 1, and the like.

[0069] 12 is a diagram illustrating the inside of the chamber 10 in step ST4. In step ST4, a fourth plasma P4 is generated in the chamber 10. Specifically, first, a fourth process gas is supplied from the gas supply unit 20 into the chamber 10. The pressure in the chamber 10 may be set to a pressure higher than that in step ST22.

[0070] In one embodiment, the fourth process gas may be appropriately selected depending on the deposits attached to the surfaces of the components in the chamber 10. For example, when the deposits are CF-based polymers, the fourth process gas may contain a fluorine-containing gas such as NF3 or CF4. The fourth process gas may contain O2 gas. The fourth process gas may contain other oxygen-containing gases such as CO gas, CO2 gas, and O3 gas, not limited to O2 gas. When the deposits include silicon or metal in addition to the CF-based polymers, the fourth process gas may contain a halogen-containing gas. The halogen-containing gas may be a chlorine-based gas such as Cl2 gas or a bromine-based gas such as HBr gas. The fourth process gas may contain the same gas as the second process gas.

[0071] In one embodiment, the fourth process gas may include an inert gas, which in one example is N2 gas.

[0072] Next, a source RF signal is supplied to the lower electrode of the substrate support 11 and / or the upper electrode of the shower head 13. This generates a high-frequency electric field between the shower head 13 and the substrate support 11. Note that a bias signal does not need to be supplied to the lower electrode of the substrate support 11.

[0073] As a result, as shown in FIG. 12, a fourth plasma P4 is generated in a space defined by the central region 111a (mounting region) of the electrostatic chuck 1111 and the shower head 13 functioning as an upper electrode. The energy density of the fourth plasma P4 may be lower than the energy density of the second plasma P2. The fourth plasma P4 cleans the inside of the chamber 10. The fourth plasma P4 can remove at least a part or all of the deposits attached to the shoulder portion 111e (around the mounting region) of the electrostatic chuck 1111. The fourth plasma P4 may remove a part or all of the deposits attached to the central region 111a (mounting region) of the electrostatic chuck 1111, the inner wall of the chamber 10, and other components (for example, the shower head 13 and the ring assembly 112). When the fourth process gas contains an inert gas, at least a part of the electrostatic chuck 1111 may be modified. For example, when the fourth process gas contains N2 gas, the fourth plasma P4 nitrides the surface of the electrostatic chuck 1111. At this time, fluorine on the surface of the electrostatic chuck 1111 can be removed.

[0074] (Step ST5: Plasma treatment of patterned substrate) In step ST5, a plasma process is performed on the patterned substrate PW. In one embodiment, the plasma process may be etching of the patterned substrate PW. FIG. 13 is a flow chart showing an example of step ST5. Step ST5 includes step ST51 of placing the patterned substrate PW, step ST52 of generating a first plasma, and step ST53 of carrying out the patterned substrate PW. FIG. 14 is a diagram showing an example of a cross-sectional structure of the patterned substrate PW. FIG. 15 is a diagram showing a schematic view of the inside of the chamber 10 in step ST52.

[0075] In step ST51, first, the patterned substrate PW is carried into the chamber 10 of the plasma processing apparatus 1. The patterned substrate PW is placed at the tip of the lifter LF in a state in which the lifter LF protrudes from the central region 111a (mounting region) of the electrostatic chuck 1111. Then, the lifter LF descends to place the patterned substrate PW in the mounting region (see FIG. 15). Then, when a predetermined voltage is applied to the electrodes of the electrostatic chuck 1111, the patterned substrate PW is electrostatically attracted to the mounting region.

[0076] In one embodiment, as shown in FIG. 14, the pattern substrate PW may have a structure in which an undercoat film UF, an etching target film EF, and a mask MK are stacked. The undercoat film UF may be, for example, a silicon wafer or an organic film, a dielectric film, a metal film, a semiconductor film, or the like formed on a silicon wafer (including both cases where the film is formed on the surface of a silicon wafer and cases where the film is formed on the surface of another film formed on a silicon wafer). The undercoat film UF may be configured by stacking a plurality of layers. The etching target film EF may be, for example, an organic film or a dielectric film. The organic film may be, for example, a spin-on carbon film (SOC), a photoresist film, or amorphous carbon. The dielectric film may be, for example, a silicon oxide film, a silicon nitride film, a Si-ARC, or SiON.

[0077] The mask MK is a film, such as a photoresist, that functions as a mask in etching the film EF to be etched. The mask MK is formed to have at least one sidewall. The sidewall defines at least one opening OP on the film EF to be etched. The opening OP is a space on the film EF to be etched, and is surrounded by the sidewall. That is, in FIG. 14, the film EF to be etched has an area covered by the mask MK and an area exposed at the bottom of the opening OP.

[0078] In step ST52, a first plasma is generated in the chamber 10. The first plasma may be generated under the same conditions as in step ST1 using a first processing gas. As a result, as shown in FIG. 15, a first plasma P1 is generated in a space defined by the patterned substrate PW arranged in the placement area and the shower head 13 functioning as an upper electrode. When a bias signal is supplied, a bias potential is generated between the first plasma P1 and the patterned substrate PW. The bias potential attracts active species such as ions and radicals in the first plasma P1 to the patterned substrate PW. As a result, the portion of the etching target film EF exposed at the opening OP of the mask MK is etched. In the process of etching the etching target film EF, an etching by-product may be generated. The by-product adheres to, for example, the shoulder portion 111e (around the placement area) of the electrostatic chuck 1111.

[0079] In step ST53, the patterned substrate PW is carried out to the outside of the chamber 10.

[0080] Note that the process ST5 may be performed for each of a plurality of patterned substrates PW, that is, the process ST5 may be repeatedly performed a plurality of times in succession.

[0081] (Process ST6: Waferless cleaning) In step ST6, waferless cleaning is performed. Step ST6 may be performed in the same manner as step ST4. Step ST6 is not essential and may be performed as appropriate depending on the state of contamination of components in the chamber 10, the continuous use time of the plasma processing apparatus 1, and the like.

[0082] (Step ST7: Loading of dummy board) In step ST7, first, a dummy substrate DW is loaded into the chamber 10 of the plasma processing apparatus 1. The dummy substrate DW may be the dummy substrate DW used for seasoning in step ST1. That is, the dummy substrate DW may be the dummy substrate DW that is loaded out of the chamber 10 in step ST3 and stored in an external accommodation chamber (e.g., a FOUP). Since the dummy substrate DW is cleaned in step ST2, it is avoided or suppressed from becoming a contamination source in the chamber 10.

[0083] (Step ST8: Cleaning) In step ST8, the inside of the chamber 10 is cleaned. Step ST8 may be performed in the same manner as step ST2.

[0084] (Step ST9: Determining the stopping condition) In step ST9, it is determined whether or not the stop condition is satisfied. The stop condition may be appropriately set based on the number of times each step is repeated, the usage time of the plasma processing apparatus, the number of processed patterned substrates PW, etc. If it is determined that the stop condition is satisfied, the present processing method is terminated. If it is determined that the stop condition is not satisfied, the process returns to step ST3 and each step is repeated.

[0085] According to this processing method, in step ST2, the dummy substrate DW used for seasoning is cleaned, and dirt due to seasoning is removed. This makes it possible to increase the number of times the dummy substrate DW is used (the number of times it is used as a dummy substrate for seasoning). As described above, the dummy substrate DW can be used for cleaning (step ST8) after the plasma processing of the pattern substrate PW. According to this processing method, it is not necessary to separately prepare a dummy substrate for seasoning and a dummy substrate for cleaning.

[0086] In the above example, the control unit 2 controls each part of the plasma processing apparatus 1 shown in FIG. 2 to execute the present processing method. However, the plasma processing apparatus 1 may be configured, for example, as follows.

[0087] 16 and 17 are diagrams showing modified examples of the substrate support 11 of the plasma processing apparatus 1. For example, as shown in FIG. 16, the substrate support 11 may include a cylindrical cover member 140 disposed radially outside the main body 111, and an annular cover ring 142 disposed on the cover member 140. The cover ring 142 may be made of an insulating material. In this example, the ring assembly 112 is supported by both the electrostatic chuck 1111 and the cover ring 140. That is, the inner peripheral portion of the ring assembly 112 is disposed on the annular region 111b of the electrostatic chuck 111, and the outer peripheral portion of the ring assembly 112 is disposed on the inner peripheral region 142a of the cover ring 142. The ring assembly 112 may be made of a conductive material or an insulating material.

[0088] 17, the substrate support 11 may include a cylindrical cover member 150 disposed radially outward of the main body 111, an annular ring 152 disposed on the inner circumferential surface of the cover member 150, and an annular cover ring 154 disposed on the outer circumferential surface of the cover member 150. The ring 152 may be made of an insulating material. The cover ring 152 may be made of a conductive material such as silicon. In this example, the ring assembly 112 is supported by both the electrostatic chuck 1111 and the ring 152. That is, the inner circumferential portion of the ring assembly 112 is disposed on the annular region 111b of the electrostatic chuck 111, and the outer circumferential portion of the ring assembly 112 is disposed on the region 152a on the inner circumferential side of the ring 152. The ring assembly 112 may be made of a conductive material or an insulating material.

[0089] The embodiments of the present disclosure further include the following aspects.

[0090] (Appendix 1) A substrate processing method in a plasma processing apparatus, comprising: The plasma processing apparatus includes: A chamber; a substrate support disposed within the chamber and having a mounting area on which a substrate is placed; Equipped with The substrate processing method includes: (a) a step of performing seasoning using a dummy substrate, (a1) placing the dummy substrate in the placement area; (a2) generating a first plasma from a first process gas containing carbon and fluorine in the chamber with the dummy substrate placed in the placement area; (b) cleaning the inside of the chamber, (b1) holding the dummy substrate at a position spaced apart from the mounting area so as to face the mounting area; (b2) generating a second plasma from a second process gas in the chamber while the dummy substrate is held at the separated position, thereby cleaning an area including at least a periphery of the placement area and the dummy substrate; A substrate processing method comprising:

[0091] (Appendix 2) The substrate processing method of claim 1, wherein the step (b) further includes the step of (b3) generating a third plasma from a third processing gas in the chamber with the dummy substrate placed in the placement area, to clean at least the dummy substrate.

[0092] (Appendix 3) The substrate processing method according to claim 2, wherein (b3) is carried out after (b2).

[0093] (Appendix 4) The substrate processing method according to claim 2, wherein (b3) is carried out before (b1).

[0094] (Appendix 5) The substrate processing method according to claim 2, wherein (b3) is performed before (b1) and after (b2), respectively.

[0095] (Appendix 6) 6. The substrate processing method according to claim 1, wherein the second process gas contains at least one of an oxygen-containing gas and a fluorine-containing gas.

[0096] (Appendix 7) 7. The substrate processing method according to claim 1, wherein the separated position is a position that is 0.01 mm or more and 1 mm or less from the placement area.

[0097] (Appendix 8) 6. The substrate processing method according to claim 2, wherein the third process gas contains at least one of an oxygen-containing gas and a fluorine-containing gas.

[0098] (Appendix 9) After (b) above, (c) removing the dummy substrate from the chamber; (d) loading a substrate into the chamber and plasma processing the substrate in the chamber using the first plasma generated from the first process gas; 9. The substrate processing method according to any one of claims 1 to 8, further comprising:

[0099] (Appendix 10) After (d) above, (f) removing the substrate from the chamber; 10. The substrate processing method of claim 9, further comprising: (g) loading the dummy substrate into the chamber and performing (b) again.

[0100] (Appendix 11) During at least one of the period between (c) and (d) and the period between (f) and (g), (h) the substrate processing method of claim 10, further comprising the step of generating a fourth plasma from a fourth process gas in the chamber while the substrate and the dummy substrate are not placed in the placement area, to clean at least an area including the placement area.

[0101] (Appendix 12) 12. The substrate processing method according to claim 11, wherein the fourth process gas contains at least one of an oxygen-containing gas and a fluorine-containing gas.

[0102] (Appendix 13) 13. The substrate processing method according to claim 11, wherein the fourth process gas includes an inert gas.

[0103] (Appendix 14) A plasma processing apparatus comprising: A chamber; a substrate support disposed within the chamber and having a mounting area on which a substrate is placed; A control unit, The control unit is (a) seasoning control using a dummy substrate, (a1) placing the dummy substrate in the placement area; (a2) generating a first plasma from a first process gas containing carbon and fluorine in the chamber while the dummy substrate is placed in the placement area; (b) controlling cleaning of the dummy substrate, (b1) holding the dummy substrate at a position spaced apart from the mounting area so as to face the mounting area; (b2) generating a second plasma from a second process gas in the chamber while the dummy substrate is held at the separated position, thereby cleaning an area including at least a periphery of the placement area and the dummy substrate; The plasma processing apparatus is configured to perform the steps of:

[0104] The above embodiments are described for the purpose of explanation and are not intended to limit the scope of the present disclosure. Various modifications can be made to the above embodiments without departing from the scope and spirit of the present disclosure. For example, some components in one embodiment can be added to other embodiments. Also, some components in one embodiment can be replaced with corresponding components in other embodiments. [Explanation of symbols]

[0105] REFERENCE SIGNS LIST 1: plasma processing apparatus, 2: control unit, 10: plasma processing chamber, 10s: plasma processing space, 11: substrate support, 111a: central region, 111a: shoulder, 1111: electrostatic chuck, 13: shower head, 20: gas supply unit, 31a: first RF generator, 31b: second RF generator, 32a: first DC generator, LF: lifter

Claims

1. A substrate processing method in a plasma processing apparatus, comprising: The plasma processing apparatus includes: A chamber; a substrate support disposed within the chamber and having a mounting area on which a substrate is placed; Equipped with The substrate processing method includes: (a) a step of performing seasoning using a dummy substrate, (a1) placing the dummy substrate in the placement area; (a2) generating a first plasma from a first process gas containing carbon and fluorine in the chamber with the dummy substrate placed in the placement area; (b) cleaning the inside of the chamber, (b1) holding the dummy substrate at a position spaced from the mounting area so as to face the mounting area; (b2) generating a second plasma from a second process gas in the chamber while the dummy substrate is held at the separated position, thereby cleaning an area including at least a periphery of the placement area and the dummy substrate; A substrate processing method comprising:

2. 2. The substrate processing method of claim 1, wherein the step (b) further comprises the step of: (b3) generating a third plasma from a third processing gas in the chamber while the dummy substrate is placed in the placement area, thereby cleaning at least the dummy substrate.

3. The substrate processing method of claim 2 , wherein (b3) is performed after (b2).

4. The substrate processing method of claim 2 , wherein (b3) is performed before (b1).

5. The substrate processing method according to claim 2 , wherein the step (b3) is performed before the step (b1) and after the step (b2).

6. 6. The substrate processing method according to claim 1, wherein the second process gas contains at least one of an oxygen-containing gas and a fluorine-containing gas.

7. The substrate processing method according to claim 1 , wherein the separated position is a position that is 0.01 mm or more and 1 mm or less from the placement area.

8. 6. The substrate processing method according to claim 2, wherein the third process gas contains at least one of an oxygen-containing gas and a fluorine-containing gas.

9. After (b), (c) removing the dummy substrate from the chamber; (d) loading a substrate into the chamber and plasma processing the substrate in the chamber using the first plasma generated from the first process gas; The substrate processing method according to claim 1 , further comprising:

10. After the (d), (f) removing the substrate from the chamber; The substrate processing method according to claim 9 , further comprising: (g) carrying out the step of (b) again by carrying out the step of ...

11. During at least one of the period between (c) and (d) and the period between (f) and (g), The substrate processing method of claim 10, further comprising: (h) generating a fourth plasma from a fourth process gas in the chamber while the substrate and the dummy substrate are not placed in the placement area, to clean at least an area including the placement area.

12. 12. The substrate processing method of claim 11, wherein the fourth process gas contains at least one of an oxygen-containing gas and a fluorine-containing gas.

13. The method of claim 11 , wherein the fourth process gas comprises an inert gas.

14. A plasma processing apparatus comprising: A chamber; a substrate support disposed within the chamber and having a mounting area on which a substrate is placed; A control unit, The control unit is (a) seasoning control using a dummy substrate, (a1) placing the dummy substrate in the placement area; (a2) generating a first plasma from a first process gas containing carbon and fluorine in the chamber while the dummy substrate is placed in the placement area; (b) controlling cleaning of the dummy substrate, (b1) holding the dummy substrate at a position spaced from the mounting area so as to face the mounting area; (b2) generating a second plasma from a second process gas in the chamber while the dummy substrate is held at the separated position, thereby cleaning an area including at least a periphery of the placement area and the dummy substrate; The plasma processing apparatus is configured to perform the steps of:

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