CLEANING METHOD, SUBSTRATE PROCESSING METHOD, AND PLASMA PROCESSING APPARATUS

Abstract

To provide a technique capable of reducing the amount of charge on the surface of an electrostatic chuck.SOLUTION: A cleaning method in a substrate plasma processing apparatus includes a step (a) of generating plasma in a chamber of the plasma processing apparatus in a state in which a substrate is not held by an electrostatic chuck in the chamber, and a step (b) of applying a voltage to the electrostatic chuck to reduce the amount of charge on the surface of the electrostatic chuck while the plasma of (a) is being generated.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] Exemplary embodiments of the present disclosure relate to a cleaning method, a method for processing a substrate, and a plasma processing apparatus. [Background technology]

[0002] Patent Document 1 describes a technique for suppressing adhesion due to residual charges on the surface of an electrostatic chuck. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2014-56928 A Summary of the Invention [Problem to be solved by the invention]

[0004] The surface of an electrostatic chuck becomes charged when cleaning a plasma processing apparatus. The present disclosure provides a technique capable of reducing the amount of charge on the surface of an electrostatic chuck. [Means for solving the problem]

[0005] In one exemplary embodiment of the present disclosure, there is provided a cleaning method comprising the steps of: (a) generating a plasma in a chamber of a plasma processing apparatus while no substrate is held by an electrostatic chuck in the chamber; and (b) applying a voltage to the electrostatic chuck while the plasma of (a) is being generated, thereby reducing an amount of charge on a surface of the electrostatic chuck. Effect of the Invention

[0006] According to one exemplary embodiment of the present disclosure, a technique capable of reducing the amount of charge on the surface of an electrostatic chuck can be provided. [Brief description of the drawings]

[0007] [Figure 1]FIG. 1 is a diagram illustrating an example of a plasma processing apparatus. [Diagram 2] FIG. 2 is a diagram illustrating an example of a main body having lift pins. [Diagram 3] 1 is a diagram illustrating an example of a substrate processing system. [Figure 4] 1A to 1C are diagrams for explaining an example of a sequence of a substrate processing method. [Diagram 5] 10 is a flowchart showing an example of a second cleaning process. [Figure 6] FIG. 11 is a diagram showing an example of a sequence of supplying a processing gas, supplying high-frequency power, and applying a voltage to an electrostatic chuck in a second cleaning process. [Figure 7] 1 is a diagram for explaining an example of a charged state of a surface of an electrostatic chuck; [Figure 8A] FIG. 10 is a diagram illustrating an example of a charged state of the surface of an electrostatic chuck after a cleaning process in the case where the present cleaning method is not applied. [Figure 8B] FIG. 10 is a schematic diagram showing an example of a charged state of the surface of an electrostatic chuck during the next plasma processing in a case where the present cleaning method is not applied; [Figure 8C] 10A and 10B are schematic diagrams illustrating an example of a charged state of the surface of an electrostatic chuck after the next plasma processing in a case where the present cleaning method is not applied. [Figure 9A] 1A to 1C are diagrams illustrating an example of a charged state of the surface of an electrostatic chuck after a cleaning process when the cleaning method is applied; [Figure 9B] 10A to 10C are diagrams illustrating an example of a charged state of the surface of an electrostatic chuck during the next plasma processing in the case where the cleaning method is applied; [Figure 9C] 10A to 10C are diagrams illustrating an example of a charged state of the surface of an electrostatic chuck after the next plasma processing when the cleaning method is applied. [Figure 10] 1 is a graph showing the relationship between lift pin torque differential and applied voltage. [Figure 11] 13 is a graph showing the relationship between the residual charge difference and the applied voltage. [Figure 12] 1 is a graph showing the effect of reducing the amount of particles by the present cleaning method. [Figure 13] FIG. 1 is a diagram illustrating an example of a plasma processing apparatus having a measuring device. [Figure 14] FIG. 13 is a diagram showing an example of correlation data between the charged state (potential V1) and the applied voltage. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

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

[0009] In one exemplary embodiment, a cleaning method is provided that includes the steps of: (a) generating a plasma in a chamber of a plasma processing apparatus while no substrate is held by the electrostatic chuck in the chamber; and (b) applying a voltage to the electrostatic chuck while the plasma of (a) is being generated, so as to reduce an amount of charge on a surface of the electrostatic chuck.

[0010] In one exemplary embodiment, (a) includes a step of supplying power for plasma generation, and after starting the supply of power for plasma generation in (a), starting application of a voltage to the electrostatic chuck in (b), and before stopping the supply of power for plasma generation in (a), stopping application of the voltage to the electrostatic chuck in (b).

[0011] In one exemplary embodiment, (a) includes a step of supplying a gas for plasma generation, and after starting the supply of the gas for plasma generation in (a), starting application of a voltage to the electrostatic chuck in (b), and before stopping the supply of the gas for plasma generation in (a), stopping application of the voltage to the electrostatic chuck in (b).

[0012] In one exemplary embodiment, the method further includes a step of (c) measuring a charged state of the electrostatic chuck surface while the plasma of (a) is being generated, and determining a voltage to be applied to the electrostatic chuck in (b) based on the charged state of the electrostatic chuck surface measured in (c).

[0013] In one exemplary embodiment, a voltage to be applied to the electrostatic chuck in (b) is determined from the measurement result of the charged state of the electrostatic chuck surface in (c) based on a relationship between the charged state of the electrostatic chuck surface and the voltage to be applied to the electrostatic chuck in that charged state of the electrostatic chuck surface.

[0014] In one exemplary embodiment, in (a), a plasma is generated in the chamber to clean a surface of an electrostatic chuck in the chamber.

[0015] In one exemplary embodiment, in (a), a plasma is generated in the chamber to clean the interior of the chamber.

[0016] In one exemplary embodiment, the method includes the steps of (a1) generating plasma in a chamber of a plasma processing apparatus while no substrate is held on the electrostatic chuck in the chamber to clean the inside of the chamber, (b1) applying a voltage to the electrostatic chuck while the plasma of (a1) is being generated to reduce the amount of charge on the electrostatic chuck surface, (a2) generating plasma in a chamber of the plasma processing apparatus while no substrate is held on the electrostatic chuck in the chamber to clean the surface of the electrostatic chuck in the chamber, and (b2) applying a voltage to the electrostatic chuck while the plasma of (a2) is being generated to reduce the amount of charge on the electrostatic chuck surface. In one exemplary embodiment, the voltages applied to the electrostatic chuck in (b1) and (b2) are different.

[0017] In one exemplary embodiment, there is provided a method for treating a substrate, comprising the above cleaning method and (c) before or after (a) and (b), holding the substrate on an electrostatic chuck and plasma treating the substrate.

[0018] In one exemplary embodiment, there is provided a method for processing a substrate, comprising the steps of: (a) generating plasma in a chamber of a plasma processing apparatus with no substrate held on an electrostatic chuck in the chamber; (b) applying a voltage to the electrostatic chuck with the plasma of (a) being generated; and (c) holding the substrate on the electrostatic chuck in the chamber of the plasma processing apparatus and plasma processing the substrate, wherein (c) is performed at least either before or after (a) and (b), and the polarity of the voltage applied to the electrostatic chuck in (b) is the same as the polarity of the voltage applied to the electrostatic chuck in (c).

[0019] In one exemplary embodiment, there is provided a plasma processing apparatus including a chamber, an electrostatic chuck that holds a substrate in the chamber, a first power supply that supplies power for generating plasma into the chamber, a second power supply that applies a voltage to the electrostatic chuck, and a controller, wherein the controller performs control including the steps of: (a) supplying power for generating plasma into the chamber by the first power supply while no substrate is held by the electrostatic chuck in the chamber, thereby generating plasma in the chamber; and (b) while the plasma of (a) is being generated, applying a voltage to the electrostatic chuck by the second power supply to reduce the amount of charge on a surface of the electrostatic chuck.

[0020] 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.

[0021] <Configuration of Plasma Processing Apparatus 1> An example of the configuration of a plasma processing system will be described below. Fig. 1 is a diagram for explaining an example of the configuration of a capacitively coupled plasma processing apparatus. A substrate processing method (hereinafter referred to as "this processing method") according to an exemplary embodiment is performed using a plasma processing apparatus 1.

[0022] The plasma processing system includes a capacitively coupled plasma processing device 1 and a controller 2. The capacitively coupled plasma processing device 1 includes a plasma processing chamber (also simply referred to as a "chamber") 10, a gas supply unit 20, a power supply 30, and an exhaust system 40. The plasma processing device 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 shower head 13. The substrate support 11 is disposed in the plasma processing chamber 10. The shower head 13 is disposed above the substrate support 11. In one embodiment, the shower head 13 constitutes 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 shower head 13, a sidewall 10a of the plasma processing chamber 10, and the substrate support 11. The plasma processing chamber 10 has at least one gas supply port for supplying at least one processing gas to the plasma processing space 10s and at least one gas exhaust port for exhausting gas from the plasma processing space. The plasma processing chamber 10 is grounded. The showerhead 13 and the substrate support 11 are electrically insulated from the plasma processing chamber 10.

[0023] The substrate support 11 includes a main body 50 and a ring assembly 51. The main body 50 has a central region 50a for supporting the substrate W and an annular region 50b for supporting the ring assembly 51. A wafer is an example of the substrate W. The annular region 50b of the main body 50 surrounds the central region 50a of the main body 50 in a plan view. The substrate W is disposed on the central region 50a of the main body 50, and the ring assembly 51 is disposed on the annular region 50b of the main body 50 so as to surround the substrate W on the central region 50a of the main body 50. Therefore, the central region 50a is also called a substrate support surface for supporting the substrate W, and the annular region 50b is also called a ring support surface for supporting the ring assembly 51.

[0024] In one embodiment, the main body 50 includes a base 60 and an electrostatic chuck 61. The base 60 includes a conductive member. The conductive member of the base 60 may function as a lower electrode. The electrostatic chuck 61 is disposed on the base 60. The electrostatic chuck 61 includes a ceramic member 61a and an electrostatic electrode 61b disposed within the ceramic member 61a. The ceramic member 61a has a central region 50a. In one embodiment, the ceramic member 61a also has an annular region 50b. Note that other members surrounding the electrostatic chuck 61, such as the annular electrostatic chuck or the annular insulating member, may have the annular region 50b. In this case, the ring assembly 51 may be disposed on the annular electrostatic chuck or the annular insulating member, or may be disposed on both the electrostatic chuck 61 and the annular insulating member. Also, an RF or DC electrode may be disposed within the ceramic member 61a, in which case the RF or DC electrode functions as a lower electrode. When a bias RF signal or DC signal, which will be described later, is connected to the RF or DC electrode, the RF or DC electrode is also called a bias electrode. It should be noted that both the conductive member of the base 60 and the RF or DC electrode may function as the two lower electrodes.

[0025] The electrostatic electrode 61b of the electrostatic chuck 61 is connected to a DC power supply 70p as a second power supply via a switch 70s. When a DC voltage from the DC power supply 70p is applied to the electrostatic electrode 61b, an electrostatic attractive force (Coulomb force) is generated between the electrostatic chuck 61 and the substrate W. The substrate W is attracted to the electrostatic chuck 61 by the electrostatic attractive force and is adsorbed and held on a surface 61c of the electrostatic chuck 61. The surface 61c of the electrostatic chuck 61 may be flat or may have an uneven shape. The electrostatic chuck 61 is not limited to a Coulomb type using the Coulomb force, and may be a Johnson-Rahbek type using the Johnson-Rahbek force.

[0026] The ring assembly 51 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.

[0027] The substrate support 11 may also include a temperature adjustment module configured to adjust at least one of the electrostatic chuck 61, the ring assembly 51, and the substrate to a target temperature. The temperature adjustment module may include a heater, a heat transfer medium, a flow passage 60a, or a combination thereof. A heat transfer fluid such as a brine or a gas flows through the flow passage 60a. In one embodiment, the flow passage 60a is formed in the base 60, and one or more heaters are disposed in the ceramic member 61a of the electrostatic chuck 61. The substrate support 11 may also include a heat transfer gas supply configured to supply a heat transfer gas between the back surface of the substrate W and the central region 50a.

[0028] As shown in FIG. 2, the main body 50 has a plurality of through holes 50c that penetrate in the vertical direction. In the main body 50, a lift pin 80 that can move in the vertical direction within the through hole 50c is provided in each through hole 50c. The lift pin 80 supports the substrate W. The lift pin 80 is an example of a lifter that supports a substrate. The lift pin 80 is driven by a driving device (not shown). The lift pin 80 can raise and lower the substrate W on or above the electrostatic chuck 61. The substrate W can be placed on the surface 61c of the electrostatic chuck 61 by lowering the lift pin 80, and the substrate W can be removed from the surface 61c of the electrostatic chuck 61 by raising the lift pin 80.

[0029] The shower head 13 shown in FIG. 1 is configured to introduce at least one processing gas from a gas supply unit 20 into a 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 an 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.

[0030] 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 one or more flow modulation devices to modulate or pulse a flow rate of the at least one process gas.

[0031] The power source 30 includes an RF power source 31 as a first power source 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), such as a source RF signal and a bias RF signal, 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 a plasma generating unit configured to generate a plasma from one or more processing gases in the plasma processing chamber 10. In addition, a bias potential is generated on the substrate W by supplying a bias RF signal to the at least one lower electrode, and ion components in the formed plasma can be attracted to the substrate W.

[0032] 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.

[0033] 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.

[0034] 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 bias 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.

[0035] In various embodiments, at least one of the first and second DC signals may be pulsed. In this case, a sequence of DC-based 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 within 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.

[0036] 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.

[0037] 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, for example, a computer 2a. The computer 2a may include, for example, a processing unit (CPU: Central Processing Unit) 2a1, a storage unit 2a2, and a communication interface 2a3. The processing unit 2a1 may be configured to read a program from the storage unit 2a2 and execute the read program to perform various control operations. 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 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).

[0038] <Configuration of the Substrate Processing System PS> 3 is a diagram illustrating a substrate processing system PS according to an exemplary embodiment. The substrate processing system PS according to an exemplary embodiment includes a plasma processing apparatus 1.

[0039] The substrate processing system PS has substrate processing chambers PM1 to PM6 (hereinafter collectively referred to as "substrate processing modules PM"), a transfer module TM, load lock modules LLM1 and LLM2 (hereinafter collectively referred to as "load lock modules LLM"), a loader module LM, and load ports LP1 to LP3 (hereinafter collectively referred to as "load ports LP"). A controller CT controls each component of the substrate processing system PS to perform a given process on a substrate W.

[0040] The substrate processing module PM performs processes such as etching, trimming, film formation, annealing, doping, lithography, cleaning, and ashing on the substrate W. A part of the substrate processing module PM may be a measurement module, which may measure the thickness of a film formed on the substrate W or the dimensions of a pattern formed on the substrate W, for example, by optical techniques. The plasma processing apparatus 1 shown in FIG. 1 is an example of the substrate processing module PM.

[0041] The transfer module TM has a transfer device for transferring a substrate W, and transfers the substrate W between the substrate processing modules PM or between the substrate processing module PM and the load lock module LLM. The substrate processing module PM and the load lock module LLM are disposed adjacent to the transfer module TM. The transfer module TM, the substrate processing module PM, and the load lock module LLM are spatially isolated from or connected to each other by an openable and closable gate valve.

[0042] The load lock modules LLM1 and LLM2 are provided between the transfer module TM and the loader module LM. The load lock module LLM can switch its internal pressure between atmospheric pressure and vacuum. The load lock module LLM transfers the substrate W from the loader module LM, which is at atmospheric pressure, to the transfer module TM, which is at vacuum, and also transfers the substrate W from the transfer module TM, which is at vacuum, to the loader module LM, which is at atmospheric pressure.

[0043] The loader module LM has a transport device for transporting the substrate W, and transports the substrate W between the load lock module LLM and the load board LP. Inside the load port LP, for example, a FOUP (Front Opening Unified Pod) capable of storing 25 substrates W or an empty FOUP can be placed. The loader module LM takes out the substrate W from the FOUP in the load port LP and transports it to the load lock module LLM. The loader module LM also takes out the substrate W from the load lock module LLM and transports it to the FOUP in the load board LP.

[0044] The controller CT controls each component of the substrate processing system PS to perform a given process on the substrate W. The controller CT stores a recipe in which a process procedure, process conditions, transport conditions, etc. are set, and controls each component of the substrate processing system PS to perform a given process on the substrate W in accordance with the recipe. The controller CT may also have some or all of the functions of the controller 2 of the plasma processing apparatus 1 shown in FIG.

[0045] <An example of this processing method> FIG. 4 is an explanatory diagram showing an example of a sequence of the present processing method performed in the plasma processing apparatus 1. In the present processing method, a process A including a plasma processing P1, a first cleaning process P2, and a second cleaning process P3 of a substrate W in this order is performed in the plasma processing apparatus 1. Hereinafter, the first cleaning process P2 is also called waferless dry cleaning (WLDC), and the second cleaning process P3 is also called waferless treatment (WLT). For example, in the plasma processing apparatus 1, the process A is repeatedly performed multiple times when processing a plurality of substrates W of one lot. The substrate W processed in the first plasma processing P1 of one lot may be a dummy substrate instead of a product substrate. In one example, the dummy substrate may be a substrate that does not have a resist film on which a pattern is formed.

[0046] <Plasma treatment P1 of substrate W> The plasma process P1 includes, for example, a process of etching a film on the substrate W using plasma.

[0047] First, the substrate W is carried into the plasma processing chamber 10 by a transport arm (not shown) and transferred to the lift pins 80 as indicated by the dashed line in Fig. 2. Next, the substrate W is lowered by the lift pins 80 and placed on the surface 61c of the electrostatic chuck 61. Next, a DC voltage is applied to the electrostatic electrode 61b of the electrostatic chuck 61 by the DC power supply 70p shown in Fig. 1. Then, the substrate W is attracted and held on the surface 61c of the electrostatic chuck 61 by the electrostatic attractive force generated between the electrostatic chuck 61 and the substrate W.

[0048] Next, a processing gas is supplied from the shower head 13 to the plasma processing space 10s. The processing gas supplied at this time includes a gas that generates active species required for etching the substrate W. High frequency power is supplied to the lower electrode by the RF power supply 31. The atmosphere in the plasma processing space 10s is exhausted from the gas exhaust port 10e, and the pressure in the plasma processing space 10s may be reduced to a predetermined pressure. As a result, plasma is generated in the plasma processing space 10s, and the substrate W is etched.

[0049] The etching process is carried out for a predetermined time, after which the supply of the processing gas to the plasma processing space 10s and the supply of high frequency power to the lower electrode are stopped, and the etching process is completed.

[0050] Thereafter, the application of the DC voltage to the electrostatic electrode 61b is stopped. Then, the substrate W is lifted by the lift pins 80 and removed from the surface 61c of the electrostatic chuck 61. The substrate W is transferred out of the plasma processing chamber 10 by a transfer arm (not shown).

[0051] <First cleaning process P2> The first cleaning process P2 includes a process of removing by-products attached to or deposited inside the plasma processing chamber 10, for example, on the side wall 10a, the ceiling wall, etc., by using plasma while the substrate W is not on the surface 61c of the electrostatic chuck 61. Note that in the first cleaning process P2, by-products attached to or deposited on the electrostatic chuck 61 may be removed.

[0052] First, after the substrate W is unloaded from the plasma processing chamber 10 in the above-mentioned plasma processing P1, a processing gas is supplied from the shower head 13 to the plasma processing space 10s in a state where the substrate W is not held on the surface 61c of the electrostatic chuck 61. The processing gas includes a gas that generates active species capable of removing by-products generated in the plasma processing P1. For example, when the by-products are CF-based polymers, the processing gas may be O2 gas. The processing gas may be other oxygen-containing gases such as CO gas, CO2 gas, and O3 gas, not limited to O2 gas. When silicon or metal is included as a by-product in addition to the CF-based polymer, the processing gas may include, for example, a halogen-containing gas in addition to the oxygen-containing gas. The halogen-containing gas is, for example, a fluorine-based gas such as CF4 gas or NF3 gas. The halogen-containing gas may be a chlorine-based gas such as Cl2 gas, or a bromine-based gas such as HBr gas.

[0053] Next, high-frequency power is supplied to the lower electrode by the RF power supply 31. The atmosphere in the plasma processing space 10s is exhausted from the gas exhaust port 10e, and the pressure in the plasma processing space 10s may be reduced to a predetermined pressure. As a result, plasma is generated in the plasma processing space 10s, and by-products in the plasma processing chamber 10 are removed. The frequency of the high-frequency power generated by the RF power supply 31 may be, for example, 10 MHz or more and 100 MHz or less, or 40 MHz or more and 100 MHz or less. The high-frequency power may be, for example, 50 W or more and 10,000 W or less, 100 W or more and 7,000 W or less, or 200 W or more and 2,000 W or less.

[0054] After the plasma has been generated for a predetermined time, the supply of high frequency power and the supply of processing gas are stopped, and the first cleaning process P2 is completed.

[0055] <Second cleaning process P3> The second cleaning process P3 includes a process of modifying the surface 61c of the electrostatic chuck 61 in the plasma processing chamber 10 using plasma while the substrate W is not on the surface 61c of the electrostatic chuck 61. The cleaning method according to the present embodiment (also referred to as the present cleaning method) is included in the second cleaning process P3. Fig. 5 is a flow chart showing an example of the second cleaning process P3, and Fig. 6 is a sequence showing the timing of supplying a processing gas (Gas) for plasma generation, supplying a high frequency power (RF) for plasma generation, and applying a voltage (ESC DC) to the electrostatic chuck 61.

[0056] When the second cleaning process P3 is started, first, the supply of a processing gas from the shower head 13 to the plasma processing space 10s is started while the substrate W is not held on the surface 61c of the electrostatic chuck 61 (step S1 in FIG. 5). The processing gas supplied at this time includes a gas that generates a plasma required to modify the surface 61c of the electrostatic chuck 61 exposed to the plasma in the plasma process P1 or the first cleaning process P2. The processing gas may be an inert gas such as N2 gas. Next, the RF power supply 31 starts supplying high-frequency power to the lower electrode (generation of plasma) (step S2 in FIG. 5). As a result, plasma is generated from, for example, N2 gas in the plasma processing space 10s, the surface 61c of the electrostatic chuck 61 is nitrided, and fluorine on the surface 61c is removed. The high-frequency power supplied in the second cleaning process P3 may be higher than the high-frequency power supplied in the first cleaning process P2. The timing at which the supply of the processing gas starts (step S1) and the timing at which the supply of the high-frequency power starts (step S2) may be simultaneous.

[0057] In a state where plasma is generated in the plasma processing space 10s (plasma generation step SA in FIG. 5), a DC voltage is applied to the electrostatic electrode 61b of the electrostatic chuck 61, and the amount of charge on the surface 61c of the electrostatic chuck 61 is reduced (step S3 in FIG. 5). For example, as shown in FIG. 7, when a positive charge is generated on the surface 61c of the electrostatic chuck 61 due to the generation of plasma, a positive DC voltage, for example, is applied to the electrostatic electrode 61b of the electrostatic chuck 61 by the DC power supply 70p. As a result, the surface 61c of the electrostatic chuck 61 is negatively charged, and the charges are offset, so that the amount of charge on the surface 61c is reduced. Conversely, when a negative charge is generated on the surface 61c of the electrostatic chuck 61, a negative DC voltage, for example, is applied to the electrostatic electrode 61b of the electrostatic chuck 61. As a result, the surface 61c of the electrostatic chuck 61 is positively charged, and the charges are offset, so that the amount of charge on the surface 61c is reduced. 7 shows an example in which the surface 61c of the electrostatic chuck 61 has an uneven shape. In one exemplary embodiment, the polarity of the voltage applied to the electrostatic chuck 61 in the cleaning process P3 is the same as the polarity of the voltage applied to the electrostatic chuck 61 in the plasma process P1 of the substrate W.

[0058] Thereafter, a process gas is supplied for a predetermined time, high frequency power is supplied to generate plasma, and a DC voltage continues to be applied to the electrostatic chuck 61 (voltage application step SB in FIG. 5).

[0059] Thereafter, the application of voltage to the electrostatic chuck 61 is stopped (step S4 in FIG. 5). Then, the supply of high frequency power is stopped (step S5 in FIG. 5), and then the supply of the processing gas is stopped (step S6 in FIG. 5). In this manner, the second cleaning process P3 is completed. In this exemplary embodiment, the plasma generation process SP is a process in which both the supply of processing gas and the supply of high frequency power are performed (steps S2 to S5), and the voltage application process SB is a process from step S4 to step S5.

[0060] According to this exemplary embodiment, the cleaning method includes a step SA of generating plasma in the chamber 10 of the plasma processing apparatus 1 in a state where the substrate W is not held on the electrostatic chuck 61 in the chamber 10, and a step SB of applying a voltage to the electrostatic chuck 61 to reduce the amount of charge on the surface 61c of the electrostatic chuck 61 in a state where the plasma is generated in the plasma generating step SA. This makes it possible to reduce the amount of charge remaining on the surface 61c of the electrostatic chuck 61 during the second cleaning process P3. As a result, it is possible to reduce the amount of particles adhering to the back surface of the substrate W in the plasma process P1 performed after the second cleaning process P3. In addition, it is possible to reduce the torque of the lift pins 80 when the substrate W is released from the electrostatic chuck 61. This point will be described in more detail with reference to FIGS. 8 and 9.

[0061] If this cleaning method is not applied, i.e., if no voltage is applied to the electrostatic chuck 61 during the cleaning process P3, positive charges remain on the surface 61c of the electrostatic chuck 61 after the cleaning process P3, as shown in FIG. 8A.

[0062] 8B, when the substrate W is attracted to the electrostatic chuck 61, the negative charges are excessively transferred from the substrate W to the electrostatic chuck 61, increasing the attracting force of the electrostatic chuck 61. In such a state, due to the difference in thermal expansion coefficient between the substrate W and the electrostatic chuck 61, the number of particles generated by friction between the back surface of the substrate W and the front surface of the electrostatic chuck 61 increases.

[0063] Furthermore, as shown in FIG. 8C, the amount of residual charge increases after the plasma processing P1, and therefore the pin torque increases when the substrate W is removed from the electrostatic chuck 61 by the lift pins.

[0064] On the other hand, when this cleaning method is applied, that is, when a voltage is applied to the electrostatic chuck 61 during the cleaning process P3, it is possible to reduce the positive charge remaining on the surface 61c of the electrostatic chuck 61 after the cleaning process P3, as shown in FIG. 9A.

[0065] 9B, when the substrate W is attracted to the electrostatic chuck 61 during the next plasma processing P1, the transfer of negative charges from the substrate W to the electrostatic chuck 61 is suppressed, and an increase in the attracting force of the electrostatic chuck 61 is suppressed. As a result, particles generated by friction between the back surface of the substrate W and the front surface of the electrostatic chuck 61 can be reduced.

[0066] Furthermore, as shown in FIG. 9C, since an increase in the residual charge after the plasma processing P1 is suppressed, an increase in the pin torque when the substrate W is released from the electrostatic chuck 61 by the lift pins can be suppressed.

[0067] According to this exemplary embodiment, after the supply of high frequency power for generating plasma is started in the plasma generation step SA (after step S2), the application of voltage to the electrostatic chuck 61 is started, and before the supply of high frequency power for generating plasma is stopped in the plasma generation step SA (before step S5), the application of voltage to the electrostatic chuck 61 is stopped. This causes a voltage to be applied to the electrostatic chuck 61 only while plasma is being generated. As a result, it is possible to prevent discharge that may occur due to the application of a voltage to the electrostatic chuck 61 in a state in which plasma is not being generated.

[0068] According to this exemplary embodiment, application of a voltage to the electrostatic chuck 61 is started after the supply of the processing gas for plasma generation is started in the plasma generation step SA (after step S1), and application of a voltage to the electrostatic chuck 61 is stopped before the supply of the processing gas for plasma generation is stopped in the plasma generation step SA (before step S6). This causes a voltage to be applied to the electrostatic chuck 61 only while plasma is being generated. As a result, it is possible to prevent discharge that may occur due to application of a voltage to the electrostatic chuck 61 in a state in which plasma is not being generated.

[0069] In the plasma generation step SA of the cleaning method in this exemplary embodiment, plasma is generated in the chamber 10 to clean the surface 61c of the electrostatic chuck 61 in the chamber 10. In the second cleaning process P3, the plasma state tends to leave a large amount of charge on the surface 61c of the electrostatic chuck 61. For this reason, by applying a voltage to the electrostatic chuck 61 in the second cleaning process P3, the amount of residual charge can be effectively reduced.

[0070] According to this exemplary embodiment, the present processing method includes a step SA of generating plasma in the chamber 10 of the plasma processing apparatus 1 in a state where the substrate W is not held on the electrostatic chuck 61 in the chamber 10, a step of applying a voltage to the electrostatic chuck 61 to reduce the amount of charge on the surface 61c of the electrostatic chuck 61 in a state where the plasma is generated in the plasma generating step SA, and a step (plasma processing P1) of holding the substrate W on the electrostatic chuck 61 in the chamber 10 of the plasma processing apparatus 1 and processing the substrate W with plasma. This makes it possible to reduce the amount of charge remaining on the surface 61c of the electrostatic chuck 61 during, for example, the second cleaning processing P3 when the substrate W is not held on the electrostatic chuck 61. Then, the plasma processing P1 in which the substrate W is held on the electrostatic chuck 61 is performed, for example, after the second cleaning processing P3, and in this plasma processing P1, it is possible to reduce particles adhering to the back surface of the substrate W. In addition, it is possible to reduce the torque of the lift pins 80 when the substrate W is released from the electrostatic chuck 61. Furthermore, even if charges generated by the plasma process P1 performed before the second cleaning process P3 remain on the electrostatic chuck 61, the second cleaning process P3 can reduce the residual charges from the previous plasma process P1 and the residual charges generated during the second cleaning process P3 together.

[0071] According to this exemplary embodiment, the plasma processing apparatus 1 includes a chamber 10, an electrostatic chuck 61 that holds a substrate W in the chamber 10, an RF power supply 31 as a first power supply that supplies power for generating plasma into the chamber 10, a DC power supply 70p as a second power supply that applies a voltage to the electrostatic chuck 61, and a control unit 2. The control unit 2 executes a step SA of supplying power for generating plasma into the chamber 10 by the RF power supply 31 to generate plasma in the chamber 10 while the substrate W is not held on the electrostatic chuck 61 in the chamber 10, and a step of applying a voltage to the electrostatic chuck 61 by the DC power supply 70p while the plasma is being generated in the plasma generation step SA to reduce the amount of charge on the surface 61c of the electrostatic chuck 61. This makes it possible to reduce the amount of charge remaining on the surface 61c of the electrostatic chuck 61 during, for example, the second cleaning process P3 when the substrate W is not held on the electrostatic chuck 61 in the substrate processing using the plasma processing apparatus 1. Then, the plasma processing P1 in which the substrate W is held by the electrostatic chuck 61 is performed, for example, after the second cleaning processing P3, and in this plasma processing P1, it is possible to reduce particles adhering to the back surface of the substrate W. Also, it is possible to reduce the torque of the lift pins 80 when removing the substrate W from the electrostatic chuck 61.

[0072] <Example> In the plasma processing P1 after the cleaning process using the present cleaning method, the torque of the lift pins required to detach the substrate W from the electrostatic chuck 61 was measured. In addition, in the plasma processing P1 after the conventional cleaning process not using the present cleaning method, the torque of the lift pins required to detach the substrate W from the electrostatic chuck 61 was measured. The graph in FIG. 10 shows the difference between the torque of the lift pins in the plasma processing P1 after the cleaning process using the present cleaning method and the torque of the lift pins in the plasma processing P1 after the conventional cleaning process. The horizontal axis of the graph in FIG. 10 is the voltage applied to the electrostatic chuck 61. From the measurement results, it can be confirmed that the torque of the lift pins during the plasma processing P1 is reduced by applying an appropriate voltage to the electrostatic chuck 61.

[0073] In the plasma processing P1 after the cleaning process using the present cleaning method, the residual charge on the surface of the electrostatic chuck 61 was measured. In addition, in the plasma processing P1 after the conventional cleaning process not using the present cleaning method, the residual charge on the surface of the electrostatic chuck 61 was measured. The graph in FIG. 11 shows the difference in the residual charge in the plasma processing P1 after the cleaning process using the present cleaning method and the residual charge in the plasma processing P1 after the conventional cleaning process. The horizontal axis of the graph in FIG. 11 is the voltage applied to the electrostatic chuck 61. From these measurement results, it can be confirmed that the residual charge during the plasma processing P1 is reduced by applying an appropriate voltage to the electrostatic chuck 61.

[0074] The amount of rear surface particles on the substrates (three substrates W1, W2, W3) by the plasma processing P1 performed alone (case C1), the amount of rear surface particles on the substrates (three substrates W1, W2, W3) by the plasma processing P1 after the second cleaning processing P3 to which the present cleaning method is applied (case C2), and the amount of rear surface particles on the substrates (three substrates W1, W2, W3) by the plasma processing P1 after the second cleaning processing P3 to which the present cleaning method is not applied (case C3) were measured. These were then compared. The results are shown in the graph of FIG. 12. Note that "Pt" in FIG. 12 means rear surface particles. From these measurement results, it can be confirmed that the amount of rear surface particles on the substrates W is reduced in the plasma processing P1 (case C2) performed after the second cleaning processing P3 to which the present cleaning method is applied.

[0075] <Other exemplary embodiments of the present cleaning method> In the present cleaning method, the voltage applied to the electrostatic chuck 61 may be a value that is determined in advance based on a theoretical value, an empirical rule, or the like. In addition, in the present cleaning method, the voltage applied to the electrostatic chuck 61 may be determined based on a charged state of the surface 61c of the electrostatic chuck 61 measured. For example, the present cleaning method may include a step of measuring a charged state of the surface of the electrostatic chuck 61 while the plasma is being generated in the plasma generation step SA, and the voltage applied to the electrostatic chuck 61 may be determined based on the charged state of the surface 61c of the electrostatic chuck 61 measured in the charged state measuring step. Furthermore, the voltage applied to the electrostatic chuck 61 may be determined from the measurement result of the charged state of the surface 61c of the electrostatic chuck 61 based on the relationship between the charged state of the surface 61c of the electrostatic chuck 61 and the voltage to be applied to the electrostatic chuck 61 in that charged state. One such exemplary embodiment will be described.

[0076] <Configuration of the Measuring Device 100> In one exemplary embodiment, the charged state of the surface 61c of the electrostatic chuck 61 corresponds to the potential V1 of the electrostatic electrode 61b of the electrostatic chuck 61. For example, when the surface 61c of the electrostatic chuck 61 is positively charged, the potential V1 of the electrostatic electrode 61b decreases and becomes negative. When the surface 61c of the electrostatic chuck 61 is negatively charged, the potential V1 of the electrostatic electrode 61b increases and becomes positive. Therefore, as shown in FIG. 13, the plasma processing apparatus 1 of one exemplary embodiment includes a measurement apparatus 100 that measures the potential V1 of the electrostatic electrode 61b, which corresponds to the charged state of the surface 61c of the electrostatic chuck 61.

[0077] The measuring device 100 includes, for example, a filter 101, a copper disk 102, a copper plate 103, an acrylic plate 104, a probe 105, and a surface electrometer 106. The probe 105 and the surface electrometer 106 constitute a potential measuring system 107.

[0078] Although the switch 70s of the electrostatic chuck 61 is illustrated separately from the measuring device 100 for convenience of explanation, the measuring device 100 may include the switch 70s. The switch 70s switches the connection of the electrostatic electrode 61b between the DC power source 70p and a member having electrostatic capacitance of the measuring device 100. The switch 70s connects the electrostatic electrode 61b to the measuring device 100 at the timing of measuring the charged state of the surface 61c of the electrostatic chuck 61. The member having the configuration in which the acrylic plate 104 is sandwiched between the copper disk 102 and the copper plate 103 is an example of a member having electrostatic capacitance. The member having electrostatic capacitance is not limited to the configuration of the copper disk 102, the copper plate 103, and the acrylic plate 104, but may be composed of an insulated conductor.

[0079] In the potential measurement system 107, the potential generated on the acrylic plate 104 between the copper disk 102 and the copper plate 103 is measured by a surface electrometer 106 using a probe 105 provided on the surface of the copper disk 102 in a non-contact manner. The potential measurement system 107 is an example of a measurement unit that measures a value corresponding to the amount of charge accumulated in a member having a capacitance. The probe 105 may be in contact with the copper disk 102 or may be non-contact, as long as it can measure the potential difference between the copper disk 102 and the copper plate 103.

[0080] A filter 101 for removing high-frequency power is provided between the switch 70s and the member having capacitance. This prevents the high-frequency power from being transmitted to the measurement device 100. When the switch 70s is switched from the side connected to the DC power supply 70p to the side connected to the member having capacitance of the measurement device 100, it becomes possible to measure the potential V1 generated in the member having capacitance, that is, to measure the potential V1 of the electrostatic electrode 61b in a floating state.

[0081] Specifically, the copper plate 103 is grounded, and the potential measured by a surface electrometer 106 using a probe 105 provided in a non-contact manner on the surface of the copper disk 102 becomes the potential V1 of the electrostatic electrode 61b in the floating state.

[0082] Information on the potential V1 measured by the surface electrometer 106 is output to the control unit 2 as information indicating the charged state of the electrostatic chuck 61, and the control unit 2 controls the DC power supply 70p based on the information to apply a voltage to the electrostatic chuck 61 that reduces the amount of charge on the surface 61c of the electrostatic chuck 61.

[0083] 14 (e.g., potential V1) and the voltage to be applied to the electrostatic chuck 61 in that charged state. The correlation data D may be created from data obtained by operating the plasma processing apparatus 1 before processing the substrate W, or may be created from theoretical values, calculated values, etc. Based on the correlation data D and the measurement result of the charged state of the surface 61c of the electrostatic chuck 61 by the measuring apparatus 100, the control unit 2 determines the voltage to be applied to the electrostatic chuck 61 in accordance with the measured amount of charge generated by the plasma during the cleaning process.

[0084] <Second cleaning process P3 using the measuring device 100> In the second cleaning process P3, the measuring device 100 measures the potential V1 of the electrostatic electrode 61b. This potential V1 corresponds to the charged state of the surface 61c of the electrostatic chuck 61. This measurement may be performed continuously in the second cleaning process P3, may be performed intermittently multiple times, or may be performed once at a specific time.

[0085] Specifically, the measuring device 100 uses a probe 105 to measure the potential V1 of the electrostatic electrode 61b of the electrostatic chuck 61 with a surface electrometer 106. The measured potential V1 is output to the control unit 2, and the control unit 2 determines the voltage (positive or negative, value, etc. of the voltage) to be applied to the electrostatic chuck 61 from the potential V1 (charged state) based on the correlation data D.

[0086] The control unit 2 controls the DC power supply 70p to apply a voltage to the electrostatic electrode 61b of the electrostatic chuck 61 such that the amount of charge on the surface 61c of the electrostatic chuck 61 decreases. For example, when the potential V1 of the electrostatic electrode 61b of the electrostatic chuck 61 changes in a positive direction, i.e., when the surface 61c of the electrostatic chuck 61 is positively charged, a positive voltage is applied to the electrostatic electrode 61b of the electrostatic chuck 61 in order to supply a negative charge to the surface 61c of the electrostatic chuck 61. Moreover, the greater the amount of positive potential change of the electrostatic electrode 61b, the higher the positive voltage is applied to the electrostatic electrode 61b of the electrostatic chuck 61.

[0087] Conversely, when the potential V1 of the electrostatic electrode 61b of the electrostatic chuck 61 changes in the negative direction, i.e., when a negative charge is applied to the surface 61c of the electrostatic chuck 61, a negative voltage is applied to the electrostatic electrode 61b of the electrostatic chuck 61 in order to supply a positive charge to the surface 61c of the electrostatic chuck 61. Moreover, the smaller the amount of change in the negative potential of the electrostatic electrode 61b, the lower the negative voltage that is applied to the electrostatic electrode 61b of the electrostatic chuck 61.

[0088] According to this exemplary embodiment, the amount of charge on the surface 61c of the electrostatic chuck 61 can be reduced accurately and reliably.

[0089] The measuring device for measuring the charged state of the surface 61c of the electrostatic chuck 61 is not limited to the configuration of the measuring device 100. This measuring device does not have to measure the potential V1 of the electrostatic electrode 61b as long as it directly measures the charged state of the surface 61c of the electrostatic chuck 61 or measures a value corresponding to the charged state.

[0090] <Application of the cleaning method to the first cleaning process P2> This cleaning method may be applied to the first cleaning process P2.

[0091] In this case, when the first cleaning process P2 is started, first, the supply of a processing gas from the shower head 13 to the plasma processing space 10s is started while the substrate W is not held on the surface 61c of the electrostatic chuck 61. The processing gas supplied at this time includes a gas that generates plasma required for removing by-products generated in the plasma process P1. Next, the RF power supply 31 starts to supply high-frequency power to the lower electrode. This generates plasma in the plasma processing space 10s, and the by-products inside the plasma processing chamber 10 are removed. This generates plasma in the plasma processing space 10s, and the by-products in the plasma processing chamber 10 are removed. In a state in which this plasma is being generated, a voltage is applied to the electrostatic chuck 61, and the amount of charge on the surface 61c of the electrostatic chuck 61 is reduced. For example, as shown in FIG. 7, when a positive charge is generated on the surface 61c of the electrostatic chuck 61 due to the generation of plasma, for example, a positive DC voltage is applied to the electrostatic electrode 61b of the electrostatic chuck 61. As a result, the surface 61c of the electrostatic chuck 61 becomes negatively charged, and the charges are offset, reducing the amount of charge on the surface 61c. Conversely, when negative charges are generated on the surface 61c of the electrostatic chuck 61, for example, a negative DC voltage is applied to the electrostatic electrode 61b of the electrostatic chuck 61. As a result, the surface 61c of the electrostatic chuck 61 becomes positively charged, and the charges are offset, reducing the amount of charge on the surface 61c.

[0092] Thereafter, for a predetermined time, a processing gas is supplied, high frequency power is supplied to generate plasma, and a DC voltage continues to be applied to the electrostatic chuck 61 .

[0093] Thereafter, the application of voltage to the electrostatic chuck 61 is stopped, followed by stopping the supply of high frequency power and then stopping the supply of the processing gas, thus completing the first cleaning process P2.

[0094] According to this exemplary embodiment, the amount of charge remaining on the surface 61c of the electrostatic chuck 61 during the first cleaning process P2 can be reduced.

[0095] The cleaning method may be applied only to the first cleaning process P2 without being applied to the second cleaning process P3, or may be applied to both the first cleaning process P2 and the second cleaning process P3. That is, the cleaning method may include, in the first cleaning process P2, (a1) a step of generating plasma in a chamber of a plasma processing apparatus while a substrate is not held on the electrostatic chuck in the chamber to clean the inside of the chamber, and (b1) a step of applying a voltage to the electrostatic chuck while the plasma of (a1) is being generated to reduce the amount of charge on the electrostatic chuck surface, and, in the second cleaning process P3, (a2) a step of generating plasma in a chamber of a plasma processing apparatus while a substrate is not held on the electrostatic chuck in the chamber to clean the surface of the electrostatic chuck in the chamber, and (b2) a step of applying a voltage to the electrostatic chuck while the plasma of (a2) is being generated to reduce the amount of charge on the electrostatic chuck surface. In this case, the amount of charge remaining on the surface 61c of the electrostatic chuck 61 during the first cleaning process P2 and the second cleaning process P3 can be reduced.

[0096] When the present cleaning method is applied to both the first cleaning process P2 and the second cleaning process P3, the voltage applied to the electrostatic chuck 61 in the first cleaning process P2 and the second cleaning process P3 may be different. Also, the voltage applied to the electrostatic chuck 61 in the second cleaning process P3 may be higher than that in the first cleaning process P2. In such a case, the applied voltage is higher in the second cleaning process P3 in which the electrostatic chuck 61 has a relatively large amount of charge, and therefore, for example, energy efficiency can be improved.

[0097] The cleaning method and the processing method may be modified in various ways without departing from the scope and spirit of the present disclosure. For example, some components in one embodiment may be added to other embodiments within the scope of the ordinary creativity of a person skilled in the art. Also, some components in one embodiment may be replaced with corresponding components in other embodiments.

[0098] For example, in the present cleaning method, the application of a voltage to the electrostatic chuck 61 may be performed during part or all of the time that the plasma is generated, or the application of a voltage to the electrostatic chuck 61 may be performed while the plasma is not generated.

[0099] This cleaning method can also be applied to cleaning processes other than the second cleaning process P3 and the first cleaning process P2.

[0100] This processing method can also be applied to sequences other than the sequence in which the plasma processing P1, the first cleaning processing P2, and the second cleaning processing P3 are repeated.

[0101] The present cleaning method and the present processing method may be performed using a plasma processing apparatus using any plasma source, such as an inductively coupled plasma or microwave plasma, other than the capacitively coupled plasma processing apparatus 1. [Explanation of symbols]

[0102] 1: Plasma processing apparatus, 2: Control unit, 10: Chamber, 31: RF power source, 61: Electrostatic chuck, 61c: Surface, 70p: DC power source, W: Substrate

Claims

1. 1. A cleaning method for a plasma processing apparatus that performs plasma processing on a substrate, comprising: (a) generating a plasma in a chamber of a plasma processing apparatus while a substrate is not held by an electrostatic chuck in the chamber; (b) applying a voltage to the electrostatic chuck while the plasma of (a) is being generated to reduce the amount of charge on the surface of the electrostatic chuck. Cleaning method:

2. The step (a) includes a step of supplying power for generating plasma; After starting the supply of power for generating plasma in (a), starting the application of voltage to the electrostatic chuck in (b); 2. The cleaning method according to claim 1, wherein the application of voltage to the electrostatic chuck in (b) is stopped before the supply of power for generating plasma is stopped in (a).

3. Prior to the step (a), a step of supplying a gas for plasma generation is included; After starting the supply of a gas for generating plasma in (a), starting the application of a voltage to the electrostatic chuck in (b); 3. The cleaning method according to claim 1, further comprising the step of stopping the application of the voltage to the electrostatic chuck in the step (b) before stopping the supply of the gas for generating the plasma in the step (a).

4. (c) measuring a charged state of a surface of the electrostatic chuck while the plasma of (a) is being generated; 4. The cleaning method according to claim 1, further comprising determining a voltage to be applied to the electrostatic chuck in step (b) based on the charged state of the electrostatic chuck surface measured in step (c).

5. 5. The method of claim 4, further comprising determining the voltage to be applied to the electrostatic chuck in (b) from a result of measuring the charged state of the electrostatic chuck surface in (c) based on a relationship between a charged state of the electrostatic chuck surface and a voltage to be applied to the electrostatic chuck in the charged state of the electrostatic chuck surface.

6. 6. The cleaning method according to claim 1, wherein in the step (a), a plasma is generated in a chamber to clean the surface of the electrostatic chuck in the chamber.

7. 6. The cleaning method according to claim 1, wherein in the step (a), the inside of the chamber is cleaned by generating plasma in the chamber.

8. (a1) generating plasma in a chamber of a plasma processing apparatus while a substrate is not held by an electrostatic chuck in the chamber, thereby cleaning the inside of the chamber; (b1) applying a voltage to the electrostatic chuck while the plasma of (a1) is being generated to reduce the amount of charge on a surface of the electrostatic chuck; (a2) generating plasma in a chamber of the plasma processing apparatus while no substrate is held on the electrostatic chuck in the chamber, thereby cleaning a surface of the electrostatic chuck in the chamber; 6. The cleaning method according to claim 1, further comprising: (b2) applying a voltage to the electrostatic chuck while the plasma of (a2) is being generated, thereby reducing an amount of charge on a surface of the electrostatic chuck.

9. The cleaning method according to claim 8 , wherein the voltages applied to the electrostatic chuck in (b1) and (b2) are different from each other.

10. A cleaning method according to any one of claims 1 to 9, (c) before or after (a) and (b), holding a substrate on the electrostatic chuck and subjecting the substrate to plasma processing. Method of processing the substrate.

11. A method for processing a substrate in a plasma processing apparatus, comprising: (a) generating a plasma in a chamber of a plasma processing apparatus while a substrate is not held by an electrostatic chuck in the chamber; (b) applying a voltage to an electrostatic chuck while the plasma of (a) is being generated; (c) holding the substrate on an electrostatic chuck in a chamber of the plasma processing apparatus and plasma processing the substrate; (c) is carried out at least either before or after (a) and (b); the polarity of the voltage applied to the electrostatic chuck in (b) is the same as the polarity of the voltage applied to the electrostatic chuck in (c); Method of processing the substrate.

12. A chamber; an electrostatic chuck for holding a substrate within the chamber; a first power source that supplies power for generating a plasma in the chamber; a second power supply that applies a voltage to the electrostatic chuck; A control unit, The control unit is (a) supplying electric power for generating plasma into the chamber by the first power source while a substrate is not held by an electrostatic chuck in the chamber, thereby generating plasma in the chamber; (b) applying a voltage to the electrostatic chuck by the second power source while the plasma of (a) is being generated, thereby reducing an amount of charge on a surface of the electrostatic chuck. Plasma processing equipment.

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