Plasma etching device, power supply unit, and plasma etching method

Abstract

Provided is a plasma etching device comprising: a substrate support part including an electrostatic chuck including two or more electrodes; one power supply provided for the two or more electrodes; an electrical path for electrically connecting each of the electrodes and the power supply; and a switch capable of switching on or off of the electrical connection in each of the electrical paths.

Description

Plasma etching apparatus, power supply unit, and plasma etching method

[0001] The present disclosure relates to a plasma etching apparatus, a power supply unit, and a plasma etching method.

[0002] Patent Document 1 discloses a substrate support including a dielectric portion and an electrode, a first electrostatic chuck region for holding a substrate, and a second electrostatic chuck region for holding an edge ring. It also discloses that the first electrostatic chuck region and the second electrostatic chuck region are each provided with an electrode, and that powers having different potentials are supplied to the electrodes from power supplies corresponding to the electrodes.

[0003] Japanese Patent Application Laid-Open No. 2021-44540

[0004] The technology disclosed herein reduces the power supply required for an electrostatic chuck in a plasma etching apparatus.

[0005] One aspect of the present disclosure is a plasma etching apparatus comprising: a substrate support having an electrostatic chuck with two or more electrodes; a power supply provided for each of the two or more electrodes; electrical paths electrically connecting each of the electrodes to the power supplies; and a switch capable of turning the electrical connection on or off in each of the electrical paths.

[0006] According to the present disclosure, it is possible to reduce the power supply required for an electrostatic chuck in a plasma etching apparatus.

[0007] FIG. 1 is an explanatory diagram showing a configuration example of a plasma processing system according to an embodiment; FIG. 2 is a cross-sectional view showing a configuration example of a plasma etching apparatus according to an embodiment; FIG. 3 is a partial cross-sectional view schematically showing a configuration example of an electrostatic chuck and a first DC generating unit according to an embodiment; FIG. 4 is a sequence chart showing a configuration example of a control method according to an embodiment; FIG. 5 is a partial cross-sectional view schematically showing an example of a state of an electrostatic chuck and a first DC generating unit according to an embodiment; FIG. 6 is a partial cross-sectional view schematically showing an example of a state of an electrostatic chuck and a first DC generating unit according to an embodiment;

[0008] In the manufacturing process of semiconductor devices, various processing steps are performed in which semiconductor wafers (hereinafter referred to as "substrates") are stored in processing modules under reduced pressure and the substrates are subjected to predetermined processing. These processing steps are performed using a substrate processing apparatus in which multiple processing modules are arranged around a common transfer module, for example.

[0009] A known example of the predetermined process performed in a substrate processing apparatus is a plasma etching process for a substrate placed on a substrate support provided in a chamber of a processing module, as disclosed in Patent Document 1. Such a substrate support is known to have an edge ring that is arranged to surround the periphery of the substrate in a plan view with the substrate placed at the center.

[0010] In the configuration disclosed in Patent Document 1, an electrostatic chuck provided on a substrate support includes one electrode that attracts the substrate at a position facing the substrate and two electrodes that attract the edge ring at positions facing the edge ring, thereby attracting and holding the substrate and the edge ring.

[0011] However, in the above configuration, different voltage settings may be required for the electrode facing the substrate and the other electrode facing the edge ring, so multiple power supplies were required.

[0012] Therefore, the technology disclosed herein reduces the number of power supplies in the substrate support, thereby reducing the space occupied by the power supplies, reducing the amount of materials used, and achieving cost reduction. Specifically, the technology reduces the number of power supplies that supply power to the multiple electrodes provided in the substrate support of the plasma etching apparatus.

[0013] Hereinafter, the configuration of the substrate processing apparatus according to this embodiment will be described with reference to the drawings. In this specification, elements having substantially the same functional configuration are designated by the same reference numerals, and redundant description will be omitted.

[0014] <Plasma Processing System> FIG. 1 is a diagram illustrating an example of the configuration of a plasma processing system. In one embodiment, the plasma processing system includes a plasma etching apparatus 1 and a control unit 2. The plasma processing system is an example of a substrate processing system, and the plasma etching apparatus 1 is an example of a substrate processing apparatus. The plasma etching apparatus 1 includes a plasma processing chamber 10, a substrate support 11, and a plasma generation unit 12. The plasma processing chamber 10 has a plasma processing space. The plasma processing chamber 10 also has at least one gas supply port for supplying at least one processing gas to the plasma processing space and at least one gas 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 11 is disposed in the plasma processing space and has a substrate support surface for supporting a substrate.

[0015] The plasma generating unit 12 is configured to generate plasma from at least one processing gas supplied into the plasma processing space. The plasma generated in the plasma processing space may be capacitively coupled plasma (CCP), inductively coupled plasma (ICP), electron-cyclotron-resonance plasma (ECR plasma), helicon wave plasma (HWP), or surface wave plasma (SWP). Various types of plasma generators may be used, including alternating current (AC) plasma generators and direct current (DC) plasma generators. In one embodiment, the AC signal (AC power) used in the AC plasma generator has a frequency in the range of 100 kHz to 10 GHz. Thus, AC signals include radio frequency (RF) signals and microwave signals. In one embodiment, the RF signal has a frequency in the range of 100 kHz to 150 MHz.

[0016] The controller 2 processes computer-executable instructions that cause the plasma etching apparatus 1 to perform the various steps described in this disclosure. The controller 2 may be configured to control each element of the plasma etching apparatus 1 to perform the various steps described herein. In one embodiment, part or all of the controller 2 may be included in the plasma etching apparatus 1. The controller 2 may include a processing unit 2a1, a storage unit 2a2, and a communication interface 2a3. The controller 2 may be implemented, for example, by a computer 2a. 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. The program may be stored in the storage unit 2a2 in advance or may be acquired via a medium when needed. The acquired program is stored in the storage unit 2a2 and read from the storage unit 2a2 by the processing unit 2a1 for execution. The medium may be various storage media readable by the computer 2a or 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 etching apparatus 1 via a communication line such as a local area network (LAN).

[0017] <Plasma Etching Apparatus> An example of the configuration of a capacitively coupled plasma etching apparatus 1 will be described below as an example of the plasma etching apparatus 1. FIG. 2 is a diagram for explaining an example of the configuration of the capacitively coupled plasma etching apparatus 1.

[0018] The plasma etching apparatus 1 includes a plasma processing chamber 10, a gas supply unit 20, a power supply unit 30, and an exhaust system 40. The plasma etching apparatus 1 also includes a substrate support 11 and a gas inlet unit. The gas inlet unit is configured to introduce at least one process gas into the plasma processing chamber 10. The gas inlet unit includes a showerhead 13. The substrate support 11 is disposed within the plasma processing chamber 10. The showerhead 13 is disposed above the substrate support 11. In one embodiment, the showerhead 13 forms at least a portion of the ceiling of the plasma processing chamber 10. The plasma processing chamber 10 has a plasma processing space 10s defined by the showerhead 13, a sidewall 10a of the plasma processing chamber 10, and the substrate support 11. The plasma processing chamber 10 is grounded. The showerhead 13 and the substrate support 11 are electrically insulated from the housing of the plasma processing chamber 10.

[0019] 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 a substrate W and an annular region 111b for supporting the ring assembly 112. A wafer is an example of a substrate W. The annular region 111b of the main body 111 surrounds the central region 111a of the main body 111 in a planar 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. The central region 111a for supporting the substrate W may be referred to as a substrate support region. The annular region 111b for supporting the ring assembly 112 may be referred to as a ring support region. The region of the annular region 111b for supporting the edge ring 113 may be referred to as an edge ring support region.

[0020] The main body 111 includes a base 120 and an electrostatic chuck 121. In one embodiment, the base 120 includes a conductive member. In this case, the conductive member of the base 120 may function as a lower electrode. The electrostatic chuck 121 is disposed on the base 120. The electrostatic chuck 121 includes a ceramic member 121a and a plurality of chuck electrodes 121b disposed within the ceramic member 121a. The configuration of the electrostatic chuck 121 with respect to the chuck electrodes 121b will be described in detail below. The ceramic member 121a has a central region 111a. In one embodiment, the ceramic member 121a also has an annular region 111b. Note that the annular region 111b may also be provided by another member surrounding the electrostatic chuck 121, such as an annular electrostatic chuck or an annular insulating member. 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 121 and the annular insulating member.

[0021] In one embodiment, an RF / DC electrode (not shown) coupled to an RF power supply unit 31 and / or a DC power supply unit 32 (described later) may be disposed on the ceramic member 121a. In this case, 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 referred to as a bias electrode. Note that the conductive member of the base 120 and the at least one RF / DC electrode may function as multiple lower electrodes. Alternatively, the chuck electrode 121b may function as the lower electrode. Therefore, the substrate support 11 includes at least one lower electrode.

[0022] The ring assembly 112 includes one or more annular members, including one or more edge rings 113. In one embodiment, the one or more annular members include at least one cover ring. The edge rings 113 are formed of a conductive or insulating material, and the cover rings are formed of an insulating material.

[0023] The substrate support 11 may also include a temperature adjustment module configured to adjust at least one of the electrostatic chuck 121, the ring assembly 112, and the substrate W to a target temperature. The temperature adjustment module may include a heater, a heat transfer medium, a flow passage 120a, or a combination thereof. A heat transfer fluid such as brine or a gas flows through the flow passage 120a. In one embodiment, the flow passage 120a is formed in the base 120, and one or more heaters are disposed in the ceramic member 121a of the electrostatic chuck 121. The substrate support 11 may also include a heat transfer gas supply unit configured to supply a heat transfer gas to a gap between the back surface of the substrate W and the central region 111a.

[0024] The showerhead 13 is configured to introduce at least one process gas from the gas supply unit 20 into the plasma processing space 10s. The showerhead 13 has at least one gas supply port 13a, at least one gas diffusion chamber 13b, and multiple gas inlets 13c. The process gas supplied to the gas supply port 13a passes through the gas diffusion chamber 13b and is introduced into the plasma processing space 10s from the multiple gas inlets 13c. The showerhead 13 also includes at least one upper electrode. In addition to the showerhead 13, the gas inlet may also include one or more side gas injectors (SGIs) attached to one or more openings formed in the sidewall 10a.

[0025] The gas supply unit 20 may include at least one gas source 21 and at least one flow controller 22. In one embodiment, the gas supply unit 20 is configured to supply at least one process gas from a corresponding gas source 21 to the showerhead 13 via a corresponding flow controller 22. Each flow controller 22 may include, for example, a mass flow controller or a pressure-controlled flow controller. Additionally, the gas supply unit 20 may include at least one flow modulation device that modulates or pulses the flow rate of the at least one process gas.

[0026] The power supply unit 30 includes an RF power supply unit 31 coupled to the plasma processing chamber 10 via at least one impedance matching circuit. The RF power supply unit 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 plasma to be formed from at least one processing gas supplied to the plasma processing space 10s. Therefore, the RF power supply unit 31 can function as at least a part of the plasma generation unit 12. Furthermore, by supplying a bias RF signal to the at least one lower electrode, a bias potential is generated on the substrate W, thereby attracting ion components in the formed plasma to the substrate W.

[0027] In one embodiment, the RF power supply unit 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 multiple 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.

[0028] The second RF generator 31b is coupled to at least one lower electrode via at least one impedance matching circuit and is configured to generate a bias RF signal (bias RF power). The frequency of the bias RF signal may be the same as or different from the frequency of the source RF signal. In one embodiment, the bias RF signal has a frequency lower than the frequency of the source RF signal. In one embodiment, the bias RF signal has a frequency in the range of 100 kHz to 60 MHz. In one embodiment, the second RF generator 31b may be configured to generate multiple bias RF signals having different frequencies. The generated one or more bias RF signals are supplied to at least one lower electrode. In various embodiments, at least one of the source RF signal and the bias RF signal may be pulsed.

[0029] The power supply unit 30 also includes a DC power supply unit 32 coupled to the plasma processing chamber 10. The DC power supply unit 32 includes a first DC generator 32a. The first DC generator 32a applies a first DC signal as a chucking voltage to the chuck electrode 121b. Details of the first DC generator 32a will be described later. In one embodiment, the DC power supply unit 32 includes a second DC generator 32b and a third DC generator 32c. The second DC generator 32b is connected to at least one lower electrode and configured to generate a second DC signal. The generated second DC signal is applied to at least one lower electrode. In one embodiment, the third DC generator 32c is connected to at least one upper electrode and configured to generate a third DC signal. The generated third DC signal is applied to at least one upper electrode.

[0030] In various embodiments, the second and third 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 thereof pulse waveform. In one embodiment, a waveform generator for generating a sequence of voltage pulses from the DC signal is connected between the second DC generator 32b and at least one lower electrode. Thus, the second DC generator 32b and the waveform generator constitute a voltage pulse generator. When the third DC generator 32c 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 either positive or negative polarity. Furthermore, the sequence of voltage pulses may include one or more positive voltage pulses and one or more negative voltage pulses within one period. The second and third DC generating units 32b and 32c may be provided in addition to the RF power supply unit 31, or the second DC generating unit 32b may be provided instead of the second RF generating unit 31b.

[0031] The exhaust system 40 may be connected to, for example, a gas exhaust port 10e provided at the bottom of the plasma processing chamber 10. The exhaust system 40 may include a pressure regulating valve and a vacuum pump. The pressure in the plasma processing space 10s is regulated by the pressure regulating valve. The vacuum pump may include a turbomolecular pump, a dry pump, or a combination thereof.

[0032] <Electrostatic Chuck> An example of the configuration of the electrostatic chuck 121 and the first DC generator 32a according to this embodiment will be described below. Fig. 3 is a schematic partial cross-sectional view for explaining the example of the configuration of the electrostatic chuck 121 and the first DC generator 32a. Note that Fig. 3 shows an example of a state in which a substrate W and an edge ring 113 are placed.

[0033] The electrostatic chuck 121 includes a chuck electrode 121b disposed within a ceramic member 121a. The chuck electrode 121b includes a substrate-side electrode 200, a first edge-ring-side electrode 201, and a second edge-ring-side electrode 202. In the following description, the first edge-ring-side electrode 201 and the second edge-ring-side electrode 202 may be collectively referred to simply as the "edge-ring-side electrodes 201, 202." The substrate-side electrode 200 is provided in a central region 111a within the ceramic member 121a. The edge-ring-side electrodes 201, 202 are provided in annular regions 111b within the ceramic member 121a.

[0034] The first DC generating unit 32a includes a power supply 210 and a ground 212. The power supply 210 in this embodiment is a variable DC power supply. The number of power supplies 210 provided is smaller than the number of chuck electrodes 121b. In this embodiment, only one power supply 210 is provided, which is smaller than the total number of three power supplies including the substrate-side electrode 200 and the two edge ring-side electrodes 201 and 202.

[0035] Each of the chuck electrodes 121b is electrically connected to the power source 210 and each of the chuck electrodes 121b is electrically connected to the ground 212 by a plurality of electrical paths.

[0036] The plurality of electrical paths (hereinafter referred to as "supply paths") between each of the chuck electrodes 121b and the power supply 210 includes a first path 221 provided in the ceramic member 121a of the electrostatic chuck 121 and a second path 222 provided in the first DC generator 32a. The first path 221 and the second path 222 are connected by a known electrical connection means. The second path 222 includes a common path 223 connected to the power supply 210 and a plurality of branch paths 224 connected to the common path 223 and also connected to the second paths 222 of the respective chuck electrodes 121b. Each of the branch paths 224 includes a switch (hereinafter referred to as a "supply switch 230") that can turn on or off the electrical connection of the respective supply path. In one embodiment, the supply switch 230 is an electrically controllable relay.

[0037] Furthermore, the multiple electrical paths (hereinafter referred to as "ground paths") between each of the chuck electrodes 121b and the ground 212 include a first path 221 and multiple third paths 241 provided in the first DC generating unit 32a and connected to the ground 212. The first path 221 and the third path 241 are connected by a known electrical connection means. Each of the third paths 241 includes a switch (hereinafter referred to as a "ground switch 250") that can switch on or off the electrical connection in each of the ground paths. In one embodiment, the ground switch 250 is an electrically controllable relay.

[0038] In the following description, the on or off state of the electrical connection of the supply path or the ground path may be simply referred to as "the supply path or the ground path is on or off." Furthermore, the state of the supply switch 230 or the ground switch 250 when the electrical connection of the supply path or the ground path is turned on or off may be referred to as "the supply switch 230 or the ground switch 250 is on or off."

[0039] <Method for Controlling Electrostatic Chuck and First DC Generator> A method for controlling the electrostatic chuck 121 and the first DC generator 32a according to this embodiment will be described below. FIG. 4 is a sequence chart illustrating an example of the configuration of the control method according to this embodiment. FIGS. 5 to 7 are schematic partial cross-sectional views showing example states of the electrostatic chuck 121 and the first DC generator 32a at each stage of the control method according to this embodiment. In FIG. 4, the supply switches 230 provided in the supply paths extending to the substrate-side electrode 200, the first edge ring side electrode 201, and the second edge ring side electrode 202 are referred to as supply switches 230a, 230b, and 230c, respectively. Furthermore, the ground switches 250 provided in the ground paths extending to the substrate-side electrode 200, the first edge ring side electrode 201, and the second edge ring side electrode 202 are referred to as ground switches 250a, 250b, and 250c, respectively.

[0040] The control method according to this embodiment includes a first step ST1, and in one embodiment, further includes a second step ST2 or a third step ST3.

[0041] In the first step ST1, the supply switch 230 is controlled to sequentially turn on one or more of the electrical connections of the supply paths in each of the chuck electrodes 121b, and turn off the electrical connections of the other supply paths other than the one electrically connected on, thereby sequentially applying power generated by the power supply 210 to each of the chuck electrodes 121b. Note that "turning on one or more" includes, for example, a case where one of three supply paths is turned on and the other two are turned off, and then the supply paths are sequentially turned on one by one. It also includes, for example, a case where two of the three supply paths are turned on and the other one is turned off, and then the other one is turned on and the other two are turned off.

[0042] In one embodiment, the first process ST1 includes the following processes ST11 to ST19. Note that in the following processes, all supply paths or ground paths not specifically mentioned are assumed to be in an off state.

[0043] In step ST11, the power supply 210 is controlled to supply the first power V Ａ In one embodiment, the first power V Ａ is the power to be applied to the substrate-side electrode 200, which is the power that generates a necessary and sufficient electrostatic attractive force to attract and hold the substrate W on the electrostatic chuck 121 during plasma etching. In this case, the substrate-side electrode 200 can function as an electrode in a monopolar electrostatic chuck. As an example, the first power V Ａ has a positive potential relative to the ground potential.

[0044] In step ST12, the supply switch 230 is controlled to turn on the electrical connection of the supply path connected to the substrate-side electrode 200. In this state, the first power V generated by the power supply 210 in step ST11 is turned on. Ａis applied only to the substrate side electrode 200, and is not applied to the edge ring side electrodes 201 and 202. An example of the state of the electrostatic chuck 121 and the first DC generating unit 32a in this state is shown in FIG.

[0045] In the example state shown in FIG. 5, the first power V Ａ By applying the voltage, a positive charge is accumulated on the substrate-side electrode 200, the ceramic member 121a in the central region 111a is polarized, and an attractive force is generated between the substrate W and the ceramic member 121a.

[0046] In step ST13, the supply switch 230 is controlled to turn off the electrical connection of the supply path connected to the substrate-side electrode 200, and the first power V Ａ Then, the power supply 210 is controlled to apply the first power V Ａ End the generation of

[0047] In step ST14, the power supply 210 is controlled to supply the second power V Ｂ In one embodiment, the second power V Ｂ is the power to be applied to the first edge ring side electrode 201, and during plasma etching or while the substrate W is being loaded or unloaded, a third power V Ｃ The second power V is a power that generates a necessary and sufficient electrostatic attractive force to attract and hold the edge ring 113 on the electrostatic chuck 121 together with the second edge ring side electrode 202 to which the second power V is applied. In this case, the first edge ring side electrode 201 and the second edge ring side electrode 202 can function as two electrodes in a bipolar electrostatic chuck. As an example, the second power V Ｂ has a positive potential relative to the ground potential, and the first power V Ａ has a different potential than

[0048] In step ST15, the supply switch 230 is controlled to turn on the electrical connection of the supply path connected to the first edge ring side electrode 201. In this state, the second power V generated by the power supply 210 in step ST15 Ｂis applied only to the first edge ring side electrode 201, and is not applied to the substrate side electrode 200 or the second edge ring side electrode 202. An example of the state of the electrostatic chuck 121 and the first DC generator 32a in this state is shown in FIG.

[0049] In the example state shown in FIG. 6, the first edge ring side electrode 201 is supplied with the second power V Ｂ By applying the first power V Ａ is supplied, and in step ST13, the first power V Ａ In the substrate-side electrode 200 where the application of the first power V Ａ The charge remains on the ceramic member 121a in the central region 111a, and the polarization of the ceramic member 121a in the central region 111a is maintained.

[0050] In step ST16, the supply switch 230 is controlled to turn off the electrical connection of the supply path connected to the first edge ring side electrode 201, and the second power V Ｂ Then, the power supply 210 is controlled to apply the second power V Ｂ End the generation of

[0051] In step ST17, the power supply 210 is controlled to supply the third power V Ｃ In one embodiment, a third power V Ｃ is a power to be applied to the second edge ring side electrode 202, and is a power that generates a necessary and sufficient electrostatic attractive force to attract and hold the edge ring 113 to the electrostatic chuck 121 together with the first edge ring side electrode 201 during plasma etching or during loading and unloading of the substrate W. As an example, the third power V Ｃ has a negative potential with respect to the ground potential.

[0052] In step ST18, the supply switch 230 is controlled to turn on the electrical connection of the supply path connected to the second edge ring side electrode 202. In this state, the third power V generated by the power supply 210 in step ST16 is Ｃis applied only to the second edge ring side electrode 202, and is not applied to the substrate side electrode 200 or the first edge ring side electrode 201. An example of the state of the electrostatic chuck 121 and the first DC generation unit 32a in this state is shown in FIG.

[0053] In the example state shown in FIG. 7, the second edge ring side electrode 202 is supplied with a third power V Ｃ As a result of the application of the first power V, a portion of the ceramic member 121a in the annular region 111b is polarized, and an attractive force is generated between the ceramic member 121a and the edge ring 113. As described above, the first power V Ａ The electric charge applied to the first edge ring side electrode 201 remains, and the polarization of the ceramic member 121a in the central region 111a is maintained. Ｂ The charge remains on the annular region 111b, and the polarization of the ceramic member 121a in the annular region 111b is maintained.

[0054] In step ST19, the supply switch 230 is controlled to turn off the electrical connection of the supply path connected to the second edge ring side electrode 202, and the second power V Ｂ Then, the power supply 210 is controlled to apply the third power V Ｃ End the generation of

[0055] After step ST19 is completed, step ST11 may be performed again, and steps ST11 to ST19 may be repeatedly performed in the same manner. This allows the polarization state of the ceramic member 121 a in each of the chuck electrodes 121 b to which power is not applied to be updated at regular intervals, thereby maintaining the polarization state more stably and allowing the substrate W and the edge ring 113 to be attracted and held more stably.

[0056] Next, the second process ST2 will be described. In the second process ST2, residual charges remaining on the edge ring side electrodes 201 and 202 are removed and the polarities are reversed. The "reversal of polarities" is explained as follows, for example. Now, when a second power V having a positive potential is applied, ＢIn this case, a positive charge is accumulated in the first edge ring side electrode 201 due to the application of the second power V Ｂ Even after the application of the third power V Ｃ Then, a third power V Ｃ Even after the application of the negative charge is terminated, negative charges remain on the first edge ring side electrode 201. In this case, it can be said that the polarity of the first edge ring side electrode 201 is reversed from positive charges to negative charges.

[0057] 7 remains on the first edge ring side electrode 201, the second step is performed to neutralize the first edge ring side electrode 201 and reverse the polarity. The same applies to the neutralization and polarity reverse of the second edge ring side electrode 202. In one embodiment, the second step ST2 includes the following steps ST21 to ST25.

[0058] In step ST21, the ground switch 250 is controlled to turn on the electrical connection of the ground path connected to the first edge ring side electrode 201. By step ST21, the positive charges remaining in the first edge ring side electrode 201 as shown in FIG. 7 flow to the ground via the ground path, and the first edge ring side electrode 201 becomes equal to the ground potential, thereby being neutralized.

[0059] In step ST22, the ground switch 250 is controlled to turn on the electrical connection of the ground path connected to the first edge ring side electrode 201, thereby completing the neutralization of the first edge ring side electrode 201.

[0060] In step ST23, the power supply 210 is controlled to supply the third power V Ｃ Generate.

[0061] In step ST24, the supply switch 230 is controlled to turn on the electrical connection of the supply path connected to the first edge ring side electrode 201. In this state, the third power V generated by the power supply 210 in step ST23 isＣ is applied only to the first edge ring side electrode 201, and is not applied to the substrate side electrode 200 or the second edge ring side electrode 202. In step ST24, the first edge ring side electrode 201 is supplied with a third power V Ｃ Negative charge accumulates due to the application of

[0062] In step ST25, the supply switch 230 is controlled to turn off the electrical connection of the supply path connected to the first edge ring side electrode 201, and the third power V Ｃ Then, the power supply 210 is controlled to apply the third power V Ｃ End the generation of

[0063] By the second process ST2 including the above-mentioned processes ST21 to ST25, the first edge ring side electrode 201, which had accumulated positive charges, can be changed to a state in which negative charges are accumulated, thereby switching the polarity.

[0064] The significance of the second step ST2 will be described below. As described above, the first edge ring side electrode 201 and the second edge ring side electrode 202, to which powers of opposite polarities are applied, function as two electrodes of a bipolar electrostatic chuck. The second power V applied to these two edge ring side electrodes 201 and 202 is Ｂ and the third power V Ｃ By switching the polarity, the polarized state of the ceramic member 121a can be maintained more stably, and the edge ring 113 can be attracted and held more stably.

[0065] On the other hand, when applying power of the opposite polarity by switching the polarity, a large potential difference may occur on the supply path due to the charge remaining on the edge ring side electrodes 201, 202 and the newly applied power of the opposite polarity, which may result in abnormal discharge such as arcing. In the second process ST2, the charge remaining on the edge ring side electrodes 201, 202 can be removed before applying the power of the opposite polarity, thereby suppressing such abnormal discharge.

[0066] It should be noted that, not only when the polarity is reversed, but also when the attractive force is reduced, the static elimination in steps ST21 and ST22 may be performed prior to the application of power to the substrate-side electrode 200 or the edge-ring-side electrodes 201 and 202. This refreshes the polarization state of the ceramic member 121a and restores the attractive force, thereby enabling the substrate W and the edge ring 113 to be attracted and held more stably.

[0067] Next, the third process ST3 will be described. In the third process ST3, during the generation of plasma for plasma etching, the same power is simultaneously applied to the substrate-side electrode 200 and the edge ring-side electrodes 201 and 202. In one embodiment, the third process ST3 includes the following multiple processes ST31 to ST33.

[0068] In step ST31, the power supply 210 is controlled to supply a fourth power V Ｄ In one embodiment, a fourth power V Ｄ is a power that generates a necessary and sufficient electrostatic attractive force to attract and hold the substrate W and the edge ring 113 to the electrostatic chuck 121 during plasma etching. In this case, the substrate-side electrode 200 and the edge-ring-side electrodes 201 and 202 can function as electrodes in a monopolar electrostatic chuck. As an example, the fourth power V Ｄ has a positive potential relative to the ground potential.

[0069] In step ST32, the supply switch 230 is controlled to turn on the electrical connection of the supply paths connected to the substrate-side electrode 200 and the edge ring-side electrodes 201 and 202. In this state, the fourth power V generated by the power supply 210 in step ST31 is Ｄ is applied to the substrate-side electrode 200 and the edge-ring-side electrodes 201 and 202. As a result, positive charges are accumulated in the substrate-side electrode 200 and the edge-ring-side electrodes 201 and 202, the ceramic member 121a in the central region 111a and the annular region 111b is polarized, and an attractive force is generated between the substrate W and the edge ring 113 and the ceramic member 121a.

[0070] In step ST33, the supply switch 230 is controlled to turn off the electrical connection of the supply paths connected to the substrate side electrode 200 and the edge ring side electrodes 201 and 202, and a fourth power V Ｄ Then, the power supply 210 is controlled to apply the fourth power V Ｄ End the generation of

[0071] During plasma generation, the third process ST3 causes positive charges to accumulate on all electrodes, including the substrate side electrode 200 and the edge ring side electrodes 201 and 202, thereby generating an attraction force between the substrate W and the edge ring 113 and the ceramic member 121a.

[0072] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The above-described embodiments may be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended claims. For example, the components of the above-described embodiments may be arbitrarily combined. Such an arbitrary combination naturally provides the functions and effects of each of the components involved in the combination, and also provides other functions and effects that are apparent to those skilled in the art from the description of this specification.

[0073] Furthermore, the effects described herein are merely descriptive or exemplary and are not limiting. In other words, the technology according to the present disclosure may achieve other effects that are apparent to those skilled in the art from the description of this specification, in addition to or in place of the above-described effects.

[0074] The following configuration examples also fall within the technical scope of the present disclosure: (1) A plasma etching apparatus comprising: a substrate support unit including an electrostatic chuck having two or more electrodes; a power supply provided for each of the two or more electrodes; electrical paths electrically connecting each of the electrodes to the power supply; and a switch capable of switching on or off the electrical connection in each of the electrical paths. (2) The plasma etching apparatus according to (1) above, further comprising: a control unit that controls the switches to sequentially turn on the electrical connections of the electrical paths in the electrodes one or more at a time and turn off the electrical connections of the electrical paths other than the electrical paths whose electrical connections are on, and executes control including the step of sequentially applying power generated by the power supply to the electrodes. (3) The plasma etching apparatus according to (2), wherein the two or more electrodes include a first electrode and a second electrode, and the control unit executes control including the steps of: (a) controlling the power supply to generate a first power, and controlling the switch to turn on the electrical connection of the electrical path in the first electrode and turn off the electrical connection of the other electrical paths in the other electrodes, and applying the first power generated by the power supply to the first electrode; and (b) controlling the power supply to generate a second power, and controlling the switch to turn on the electrical connection of the electrical path in the second electrode and turn off the electrical connection of the other electrical paths in the other electrodes, and applying the second power generated by the power supply to the second electrode. (4) The plasma etching apparatus according to (3), wherein the first power and the second power have different potentials. (5) The plasma etching apparatus according to (3) or (4), wherein the substrate support further comprises a substrate support region and an edge ring support region, the first electrode being provided in the substrate support region and the second electrode being provided in the edge ring support region. (6) The plasma etching apparatus according to (3) or (4), wherein the substrate support further comprises an edge ring support region, and the first electrode and the second electrode are provided in the edge ring support region.(7) The plasma etching apparatus according to (6) above, wherein the substrate support unit further comprises a substrate support region, wherein the two or more electrodes include a third electrode, wherein the third electrode is provided in the substrate support region, and wherein the control unit further executes control including the steps of: (c) controlling the power supply to generate a third power, and controlling the switch to turn on an electrical connection of the electrical path in the third electrode and turn off an electrical connection of another of the electrical paths in the other electrodes, and applying the third power generated by the power supply to the third electrode. (8) The plasma etching apparatus according to (7) above, wherein the first power, the second power, and the third power have potentials different from one another, and the first power and the second power have polarities different from one another. (9) The plasma etching apparatus according to any one of (3) to (8), wherein the control unit further executes control including the steps of: (d) controlling the power supply to generate a fourth power, and controlling the switch to turn on the electrical connections of the electrical paths in two or more of the electrodes, and applying the fourth power generated by the power supply to the electrodes whose electrical connections of the electrical paths are on. (10) The plasma etching apparatus according to any one of (3) to (9), wherein the control unit executes, in each of the steps, the steps of: (e) controlling the power supply to start generating the power, (f) controlling the switch to turn on the electrical connections of the electrical paths in the electrodes, (g) controlling the switch to turn off the electrical connections of the electrical paths that were turned on in step (f), and (h) controlling the power supply to end the generation of the power, in this order. (11) A plasma etching apparatus according to any one of (3) to (10) above, further comprising a ground path electrically connecting each of the two or more electrodes to ground, and each of the ground paths comprising a ground switch capable of switching on or off the electrical connection between the electrode and the ground, wherein the control unit further performs control including the step of: (i) controlling the ground switch to turn on the electrical connection between the electrode and the ground prior to the application of the power, and de-electrifying the electrode.(12) The plasma etching apparatus according to any one of (3) to (11), wherein the power generated by the power supply is DC power. (13) A power supply unit that applies power to two or more electrodes included in an electrostatic chuck of a plasma etching apparatus, the power supply unit comprising: a power supply provided for each of the two or more electrodes; electrical paths that electrically connect each of the electrodes to the power supply; and switches that can switch on or off the electrical connection in each of the electrical paths. (14) The power supply unit according to (13), further comprising: a ground path that connects each of the two or more electrodes to ground; and a ground switch that can switch on or off the connection between the electrode and the ground in each of the ground paths. (15) A plasma etching method using a plasma etching apparatus, wherein the plasma etching apparatus comprises: a substrate support unit having an electrostatic chuck having two or more electrodes; a power supply provided for each of the two or more electrodes; electrical paths electrically connecting each of the electrodes to the power supply; and a switch capable of switching on or off the electrical connection in each of the electrical paths; and the plasma etching method performs control including a step of controlling the switch to sequentially turn on the electrical connections of the electrical paths in the electrodes one or more at a time, and turning off the electrical connections of the electrical paths other than the electrical paths whose electrical connections are on, and sequentially applying power generated by the power supply to the electrodes.

[0075] REFERENCE SIGNS LIST 1 Plasma etching apparatus 11 Substrate support 121 Electrostatic chuck 200 Substrate side electrode 201 First edge ring side electrode 202 Second edge ring side electrode 210 Power supply 230 Supply switch

Claims

1. A plasma etching apparatus comprising: a substrate support having an electrostatic chuck having two or more electrodes; a power supply provided for each of the two or more electrodes; electrical paths electrically connecting each of the electrodes and the power supply; and a switch capable of turning the electrical connection on or off in each of the electrical paths.

2. A plasma etching apparatus as described in claim 1, further comprising a control unit which performs control including the steps of controlling the switches to sequentially turn on one or more of the electrical connections of the electrical paths in the electrodes and turn off the electrical connections of the other electrical paths other than the electrical paths whose electrical connections are on, and sequentially applying power generated by the power supply to the electrodes.

3. The plasma etching apparatus of claim 2, wherein the two or more electrodes include a first electrode and a second electrode, and the control unit executes control including the steps of: (a) controlling the power supply to generate a first power, controlling the switch to turn on the electrical connection of the electrical path at the first electrode and turn off the electrical connection of the other electrical paths at the other electrodes, and applying the first power generated by the power supply to the first electrode; and (b) controlling the power supply to generate a second power, and controlling the switch to turn on the electrical connection of the electrical path at the second electrode and turn off the electrical connection of the other electrical paths at the other electrodes, and applying the second power generated by the power supply to the second electrode.

4. The plasma etching apparatus of claim 3, wherein the first power and the second power have different potentials.

5. The plasma etching apparatus of claim 4, wherein the substrate support further comprises a substrate support region and an edge ring support region, the first electrode being provided in the substrate support region and the second electrode being provided in the edge ring support region.

6. The plasma etching apparatus of claim 4, wherein the substrate support further comprises an edge ring support region, and the first electrode and the second electrode are provided in the edge ring support region.

7. The plasma etching apparatus of claim 6, wherein the substrate support section further comprises a substrate support region, the two or more electrodes include a third electrode, the third electrode being provided in the substrate support region, and the control section further performs control including the steps of: (c) controlling the power supply to generate a third power, controlling the switch to turn on the electrical connection of the electrical path in the third electrode and to turn off the electrical connection of the other electrical paths in the other electrodes, and applying the third power generated by the power supply to the third electrode.

8. A plasma etching apparatus as recited in claim 7, wherein the first power, the second power and the third power have different potentials from each other, and the first power and the second power have different polarities.

9. A plasma etching apparatus according to any one of claims 3 to 8, wherein the control unit further executes control including the steps of: (d) controlling the power supply to generate a fourth power, controlling the switch to turn on the electrical connection of the electrical path in two or more of the electrodes, and applying the fourth power generated by the power supply to the electrode in which the electrical connection of the electrical path is on.

10. A plasma etching apparatus as described in any one of claims 3 to 8, wherein the control unit performs the following steps in order in each of the steps: (e) a step of controlling the power supply to start the generation of the electric power; (f) a step of controlling the switch to turn on the electrical connection of the electrical path in the electrode; (g) a step of controlling the switch to turn off the electrical connection of the electrical path that was turned on in step (f); and (h) a step of controlling the power supply to terminate the generation of the electric power.

11. A plasma etching apparatus as described in any one of claims 3 to 8, further comprising a ground path electrically connecting each of two or more of the electrodes to ground, each of the ground paths comprising a ground switch capable of switching on or off the electrical connection between the electrode and the ground, wherein the control unit further performs control including the steps of: (i) controlling the ground switch prior to the application of power to turn on the electrical connection between the electrode and the ground and de-electrifying the electrode.

12. A plasma etching apparatus according to any one of claims 3 to 8, wherein the power generated by the power supply is DC power.

13. A power supply unit that applies power to two or more electrodes of an electrostatic chuck of a plasma etching device, comprising: a power supply provided for each of the two or more electrodes; electrical paths that electrically connect each of the electrodes to the power supply; and a switch that can turn the electrical connection on or off in each of the electrical paths.

14. The power supply unit of claim 13, further comprising: a ground path that connects each of the two or more electrodes to ground; and a ground switch in each of the ground paths that can switch on or off a connection between the electrode and the ground.

15. A plasma etching method using a plasma etching apparatus, the plasma etching apparatus comprising: a substrate support section having an electrostatic chuck having two or more electrodes; a power supply provided for each of the two or more electrodes; electrical paths electrically connecting each of the electrodes to the power supply; and a switch capable of switching an electrical connection on or off in each of the electrical paths, the plasma etching method performing control including a step of controlling the switch to sequentially turn on the electrical connections of the electrical paths in the electrodes one or more at a time, and turn off the electrical connections of the other electrical paths other than the electrical paths whose electrical connections are on, and sequentially applying power generated by the power supply to the electrodes.

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