Plasma processing apparatus and substrate processing system

Abstract

A plasma processing apparatus includes a chamber, a substrate supporting portion, an edge ring, a lifting mechanism, a plasma generating portion, and a bias power source. The substrate supporting part is arranged in the chamber. The lifting mechanism is configured so as to be capable of moving the edge ring up and down with respect to the substrate support part. The substrate supporting part comprises a base which is electrically coupled with a bias power supply and / or a high-frequency power supply of the plasma generating part, and an electrostatic chuck on the base. The lifting mechanism comprises a conductive ring and a connecting part. The conductive ring can be electrically coupled with the edge ring in a state of supporting the edge ring placed thereon. The connection member is configured so as to be capable of maintaining an electrical connection between the conductive ring and the base in accordance with the movement of the edge ring and the conductive ring by the lifting mechanism.

Description

Technical Field

[0001] Exemplary embodiments of the present invention relate to a plasma processing apparatus and a substrate processing system. Background Art

[0002] A plasma processing apparatus is used in plasma processing of a substrate. The plasma processing apparatus includes a chamber and a substrate support portion. The substrate support portion is disposed in the chamber. The substrate support portion includes a susceptor and an electrostatic chuck. A bias power supply is connected to the susceptor, which generates an electrical bias for attracting ions from the plasma to the substrate. The electrostatic chuck is configured to be able to support the substrate and an edge ring surrounding the substrate. Patent Document 1 below discloses a plasma processing apparatus configured to be able to move the edge ring up and down.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2020-113753 Summary of the Invention

[0006] Technical Problem to be Solved by the Invention

[0007] The present invention provides a technique capable of reducing the difference between the upper end position of the plasma sheath on the edge ring and the upper end position of the plasma sheath on the substrate.

[0008] Technical Solution for Solving the Technical Problem

[0009] In an exemplary embodiment, a plasma processing apparatus is provided. The plasma processing apparatus includes a chamber, a substrate support portion, an edge ring, a lifting mechanism, a plasma generation portion, and a bias power supply. The substrate support portion is disposed in the chamber. The edge ring has conductivity and is disposed so as to surround the substrate on the substrate support portion. The lifting mechanism is configured to be able to move the edge ring up and down. The plasma generation portion includes a high-frequency power supply and is configured to be able to generate plasma in the chamber. The bias power supply is configured to be able to generate an electrical bias for attracting ions from the plasma to the substrate on the substrate support portion. The substrate support portion includes a susceptor electrically coupled to the bias power supply and / or the high-frequency power supply, and an electrostatic chuck on the susceptor. The lifting mechanism includes a conductive ring, a rod, an actuator, and a connection member. The conductive ring can be electrically coupled to the edge ring while supporting the edge ring placed thereon. The rod extends vertically downward below the conductive ring. The actuator is configured to be able to move the edge ring up and down via the rod and the conductive ring. The connection member provides an electrical connection between the conductive ring and the susceptor. The connection member is configured to be able to maintain the electrical connection as the conductive ring moves.

[0010] Advantageous Effects of the Invention

[0011] According to an exemplary embodiment, it is possible to reduce the difference between the upper end position of the plasma sheath on the edge ring and the upper end position of the plasma sheath on the substrate. Description of the Drawings

[0012] Figure 1 It is a diagram for explaining a structural example of a plasma processing system.

[0013] Figure 2 It is a diagram for explaining a structural example of an inductively coupled plasma processing apparatus.

[0014] Figure 3 It is a diagram showing a substrate support portion and a lifting mechanism according to an exemplary embodiment.

[0015] Figure 4 It is a diagram showing a substrate support portion and a lifting mechanism according to another exemplary embodiment.

[0016] Figure 5 It is a diagram showing a substrate processing system according to an exemplary embodiment.

[0017] Figure 6 It is a diagram showing a substrate support portion and a lifting mechanism according to still another exemplary embodiment.

[0018] Figure 7 It is a diagram showing a substrate support portion and a lifting mechanism according to still another exemplary embodiment.

[0019] Figure 8 It is a diagram showing a substrate support portion and a lifting mechanism according to still another exemplary embodiment.

[0020] Figure 9 It is a diagram showing a substrate support portion and a lifting mechanism according to still another exemplary embodiment.

[0021] Figure 10 It is a diagram for explaining a structural example of a capacitively coupled plasma processing apparatus.

[0022] Figure 11 It is a diagram showing a substrate support portion and a lifting mechanism according to still another exemplary embodiment.

[0023] Figure 12 It is a diagram showing a substrate support portion and a lifting mechanism according to still another exemplary embodiment.

[0024] Figure 13 It is a diagram showing a substrate support portion and a lifting mechanism according to still another exemplary embodiment.

[0025] Figure 14 It is a flowchart showing a plasma processing method according to an exemplary embodiment.

[0026] Figure 15 FIG. (a) is a diagram showing an example of an imaging device used with a plasma processing apparatus according to various exemplary embodiments. Figure 15 FIG. (b) is a diagram showing an example of a measuring instrument used with a plasma processing apparatus according to various exemplary embodiments.

[0027] Figure 16 is a flowchart showing a plasma processing method according to another exemplary embodiment.

[0028] Figure 17 is a flowchart showing a plasma processing method according to yet another exemplary embodiment.

[0029] Figure 18 is a diagram showing an example of a measuring instrument used with a plasma processing apparatus according to various exemplary embodiments.

[0030] Figure 19 is a diagram showing an edge ring and a conductive ring according to yet another exemplary embodiment.

[0031] Figure 20 is a diagram showing an edge ring and a conductive ring according to yet another exemplary embodiment.

[0032] Figure 21 is a diagram showing a substrate support portion and a lifting mechanism according to yet another exemplary embodiment.

[0033] Figure 22 is a coordinate diagram showing experimental results.

[0034] Figure 23 is a diagram showing a substrate support portion and a lifting mechanism according to an exemplary embodiment. DETAILED DESCRIPTION

[0035] Hereinafter, various exemplary embodiments will be described in detail with reference to the accompanying drawings. In addition, the same or corresponding parts are denoted by the same reference numerals in the respective drawings.

[0036] Figure 1This is a diagram for explaining a structural example of a plasma processing system. In one embodiment, the plasma processing system includes a plasma processing apparatus 1 and a control unit 2. The plasma processing system is an example of a substrate processing system, and the plasma processing apparatus 1 is an example of a substrate processing apparatus. The plasma processing apparatus 1 includes a plasma processing chamber 10, a substrate support portion 11, and a plasma generation portion 12. The plasma processing chamber 10 has a plasma processing space. In addition, the plasma processing chamber 10 has at least one gas supply port for supplying at least one processing gas to the plasma processing space, and at least one gas discharge port for discharging gas from the plasma processing space. The gas supply port is connected to a gas supply portion 20 described later, and the gas discharge port is connected to an exhaust system 40 described later. The substrate support portion 11 is disposed in the plasma processing space and has a substrate support surface for supporting a substrate.

[0037] The plasma generation portion 12 is configured to be able to generate plasma from at least one processing gas supplied into the plasma processing space. The plasma formed in the plasma processing space can be capacitively coupled plasma (CCP), inductively coupled plasma (ICP), electron-cyclotron-resonance plasma (ECR plasma), helicon wave plasma (HWP), surface wave plasma (SWP), etc. In addition, various types of plasma generation portions including an AC (alternating current) plasma generation portion and a DC (direct current) plasma generation portion can be used. In one embodiment, the AC signal (AC electric power) used in the AC plasma generation portion has a frequency in the range of 100 kHz to 10 GHz. Therefore, the AC signal includes an RF (radio frequency) signal and a microwave signal. In one embodiment, the RF signal has a frequency in the range of 100 kHz to 150 MHz.

[0038] The control unit 2 is used to process computer-executable commands for causing the plasma processing apparatus 1 to execute various steps described in the present invention. The control unit 2 can be configured to be able to control each element of the plasma processing apparatus 1 to execute the various steps described herein. In one embodiment, part or all of the control unit 2 may be included in the plasma processing apparatus 1. The control unit 2 may include a processing unit 2a1, a storage unit 2a2, and a communication interface 2a3. The control unit 2 is implemented by a computer 2a, for example. The processing unit 2a1 can be configured to be able to read a program from the storage unit 2a2 and execute the read program to perform various control operations. This program may be pre-stored in the storage unit 2a2 or may be acquired via a medium when needed. The acquired program is stored in the storage unit 2a2 and read and executed by the processing unit 2a1 from the storage unit 2a2. The medium may be various storage media readable by the computer 2a or may be a communication line connected to the communication interface 2a3. The processing unit 2a1 may be a CPU (Central Processing Unit). The storage unit 2a2 may include a RAM (Random Access Memory), a ROM (Read Only Memory), an HDD (Hard Disk Drive), an SSD (Solid State Drive), or a combination thereof. The communication interface 2a3 can communicate with the plasma processing apparatus 1 via a communication line such as a LAN (Local Area Network).

[0039] Hereinafter, a structural example of an inductively coupled plasma processing apparatus as an example of the plasma processing apparatus 1 will be described. Figure 2 It is a diagram for explaining a structural example of an inductively coupled plasma processing apparatus.

[0040] The inductively coupled plasma processing apparatus 1 includes a plasma processing chamber 10, a gas supply unit 20, a power supply 30, and an exhaust system 40. The plasma processing chamber 10 includes a dielectric window 101. In addition, the plasma processing apparatus 1 includes a substrate support portion 11, a gas introduction portion, and an antenna 14. The substrate support portion 11 is disposed inside the plasma processing chamber 10. The antenna 14 is disposed on or above the plasma processing chamber 10 (i.e., on or above the dielectric window 101). The plasma processing chamber 10 has a plasma processing space 10s defined by the dielectric window 101, the side wall 102 of the plasma processing chamber 10, and the substrate support portion 11. The plasma processing chamber 10 is grounded.

[0041] The substrate support portion 11 includes a main body portion 111 and a ring assembly 112. The main body portion 111 has a central region 111a for supporting the substrate W and an annular region 111b for supporting the ring assembly 112. The wafer is an example of the substrate W. The annular region 111b of the main body portion 111 surrounds the central region 111a of the main body portion 111 in a plan view. The substrate W is disposed on the central region 111a of the main body portion 111, and the ring assembly 112 is disposed on the annular region 111b of the main body portion 111 so as to surround the substrate W on the central region 111a of the main body portion 111. Therefore, the central region 111a is also referred to as a substrate support surface for supporting the substrate W, and the annular region 111b is also referred to as a ring support surface for supporting the ring assembly 112.

[0042] In one embodiment, the main body portion 111 includes a base 1110 and an electrostatic chuck 1111. The base 1110 includes a conductive member. The conductive member of the base 1110 can function as a bias electrode. The electrostatic chuck 1111 is disposed on the base 1110. The electrostatic chuck 1111 includes a ceramic member 1111a and an electrostatic electrode 1111b disposed within the ceramic member 1111a. The ceramic member 1111a has a central region 111a. In one embodiment, the ceramic member 1111a further has an annular region 111b. Alternatively, other components surrounding the electrostatic chuck 1111, such as an annular electrostatic chuck or an annular insulating member, may have the annular region 111b. In this case, the ring assembly 112 can be disposed on the annular electrostatic chuck or the annular insulating member, or on both the electrostatic chuck 1111 and the annular insulating member. Additionally, at least one RF / DC electrode coupled to an RF power supply 31 and / or a DC power supply 32 described later may be disposed within the ceramic member 1111a. In this case, the at least one RF / DC electrode functions as a bias electrode. Further, the conductive member of the base 1110 and the at least one RF / DC electrode may function as a plurality of bias electrodes. Additionally, the electrostatic electrode 1111b may function as a bias electrode. Therefore, the substrate support portion 11 includes at least one bias electrode.

[0043] The ring assembly 112 includes one or more annular members. In one embodiment, the one or more annular members include one or more edge rings and at least one cover ring. The edge ring is formed of a conductive material or an insulating material, and the cover ring is formed of an insulating material.

[0044] In addition, the substrate support portion 11 may also include a temperature adjustment module configured to adjust at least one of the electrostatic chuck 1111, the ring assembly 112, and the substrate to a target temperature. The temperature adjustment module may include a heater, a heat transfer medium, a flow path 1110a, or a combination thereof. A heat transfer fluid such as brine or gas flows in the flow path 1110a. In one embodiment, the flow path 1110a is formed in the base 1110, and one or more heaters are disposed in the ceramic member 1111a of the electrostatic chuck 1111. In addition, the substrate support portion 11 may include a heat transfer gas supply portion configured to supply a heat transfer gas to the gap between the back surface of the substrate W and the central region 111a.

[0045] The gas introduction portion is configured to introduce at least one process gas from the gas supply portion 20 into the plasma processing space 10s. In one embodiment, the gas introduction portion includes a central gas injector (CGI) 13. The central gas injector 13 is disposed above the substrate support portion 11 and is installed at the central opening formed in the dielectric window 101. The central gas injector 13 has at least one gas supply port 13a, at least one gas flow path 13b, and at least one gas introduction port 13c. The process gas supplied to the gas supply port 13a is introduced into the plasma processing space 10s from the gas introduction port 13c through the gas flow path 13b. In addition, regarding the gas introduction portion, in addition to or instead of the central gas injector 13, it may also include one or more side gas injectors (SGIs) installed in one or more openings formed in the side wall 102.

[0046] The gas supply portion 20 may include at least one gas source 21 and at least one flow controller 22. In one embodiment, the gas supply portion 20 is configured to supply at least one process gas from the corresponding gas source 21 to the gas introduction portion via the corresponding flow controller 22. Each flow controller 22 may include, for example, a mass flow controller or a pressure-controlled flow controller. Moreover, the gas supply portion 20 may also include at least one flow modulation device for modulating the flow rate of at least one process gas or pulsing it.

[0047] The power supply 30 includes an RF power supply 31 coupled to the plasma processing chamber 10 via at least one impedance matching circuit. The RF power supply 31 is configured to supply at least one RF signal (RF electric power) to at least one bias electrode and the antenna 14. Thereby, a plasma is formed from at least one processing gas supplied to the plasma processing space 10s. Accordingly, the RF power supply 31 can function as at least a part of the plasma generation unit 12. In addition, by supplying a bias RF signal to at least one bias electrode, a bias potential can be generated on the substrate W, and ions in the formed plasma can be attracted to the substrate W.

[0048] In one embodiment, the RF power supply 31 includes a first RF generation unit 31a and a second RF generation unit 31b. The first RF generation unit 31a is coupled to the antenna 14 via at least one impedance matching circuit and is configured to generate a source RF signal (source RF electric power) for plasma generation. In one embodiment, the source RF signal has a frequency in the range of 10 MHz to 150 MHz. In one embodiment, the first RF generation unit 31a may also be configured to generate a plurality of source RF signals having different frequencies. The generated one or more source RF signals are supplied to the antenna 14.

[0049] The second RF generation unit 31b is coupled to at least one bias electrode via at least one impedance matching circuit and is configured to generate a bias RF signal (bias RF electric power). The frequency of the bias RF signal may be the same as or different from the frequency of the source RF signal. In one embodiment, the bias RF signal has a frequency lower than the frequency of the source RF signal. In one embodiment, the bias RF signal has a frequency in the range of 100 kHz to 60 MHz. In one embodiment, the second RF generation unit 31b may also 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 bias electrode. Further, in various embodiments, at least one of the source RF signal and the bias RF signal may be pulsed.

[0050] In addition, the power supply 30 may include a DC power supply 32 coupled to the plasma processing chamber 10. The DC power supply 32 includes a bias DC generation unit 32a. In one embodiment, the bias DC generation unit 32a is connected to at least one bias electrode and is configured to generate a bias DC signal. The generated bias DC signal is applied to at least one bias electrode.

[0051] In various embodiments, the bias DC signal may also be pulsed. In this case, a sequence of voltage pulses is applied to at least one bias electrode. The voltage pulses may have a pulse waveform such as rectangular, trapezoidal, triangular, or a combination thereof. In one embodiment, a waveform generation unit for generating a sequence of voltage pulses from a DC signal is connected between the bias DC generation unit 32a and at least one bias electrode. Thus, the bias DC generation unit 32a and the waveform generation unit constitute a voltage pulse generation unit. The voltage pulses may have a positive polarity or a negative polarity. Additionally, the sequence of voltage pulses may include one or more positive-polarity voltage pulses and one or more negative-polarity voltage pulses within one cycle. Further, the bias DC generation unit 32a may be provided together with the RF power supply 31, or the bias DC generation unit 32a may be provided in place of the second RF generation unit 31b.

[0052] The antenna 14 includes one or more coils. In one embodiment, the antenna 14 may include an outer coil and an inner coil arranged coaxially. In this case, the RF power supply 31 may be connected to both the outer coil and the inner coil, or may be connected to either the outer coil or the inner coil. In the former case, it may be the same RF generation unit that is connected to both the outer coil and the inner coil, or different RF generation units may be connected to the outer coil and the inner coil respectively.

[0053] The exhaust system 40 can be connected, for example, to a gas discharge 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 within the plasma processing space 10s can be regulated by the pressure regulating valve. The vacuum pump may include a turbo molecular pump, a dry pump, or a combination thereof.

[0054] Hereinafter, with reference to Figure 3 。 Figure 3 is a diagram showing a substrate support portion and a lifting mechanism of an exemplary embodiment. Figure 3 The substrate support portion 11 and the lifting mechanism 50 shown can be employed in the plasma processing apparatus 1.

[0055] As described above, the substrate support portion 11 is configured to be able to support the edge ring UR (upper edge ring). The edge ring UR is a part of the ring assembly 112. The edge ring UR is arranged so as to surround the substrate W on the substrate support portion 11. The edge ring UR is formed of a conductive material such as silicon, silicon carbide, or tungsten.

[0056] The substrate support portion 11, as described above, includes a base 1110 and an electrostatic chuck 1111. The base 1110 is a conductive member or includes a conductive member therein. The base 1110 (or its conductive member) is electrically coupled to at least one bias power supply such as the second RF generation unit 31b and / or the bias DC generation unit 32a. The at least one bias power supply includes the second RF generation unit 31b and / or the first DC generation unit 32a. The at least one bias power supply is configured to be able to generate an electrical bias to attract ions from the plasma to the substrate W on the substrate support portion 11. The electrical bias includes the above-described bias RF signal and / or a sequence of voltage pulses.

[0057] The electrostatic chuck 1111 is disposed on the base 1110. The electrostatic chuck 1111 includes a first portion P1 and a second portion P2. The first portion P1 has a substrate support surface (i.e., the central region 111a) as its upper surface. The first portion P1 and the substrate support surface have a substantially circular planar shape. The central axis of the first portion P1 and the substrate support surface is the central axis of the substrate support portion 11. The first portion P1 includes the above-described electrostatic electrode 1111b. When a DC voltage is applied to the electrostatic electrode 1111b from a DC power supply, an electrostatic attraction is generated between the first portion P1 and the substrate W. The first portion P1 uses the generated electrostatic attraction to hold the substrate W.

[0058] The second portion P2 extends circumferentially around the central axis of the substrate support portion 11 so as to surround the first portion P1. The second portion P2 has an annular support surface (i.e., the annular region 111b) as its upper surface. The second portion P2 and the annular support surface have a substantially annular planar shape. The second portion P2 may include at least one electrostatic electrode. The second portion P2 may include the electrode BEa and the electrode BEb as the at least one electrostatic electrode. The electrode BEa and the electrode BEb constitute a bipolar electrode. A voltage is applied to the electrode BEa and the electrode BEb from at least one power supply to generate a potential difference therebetween. Thus, an electrostatic attraction is generated between the edge ring UR and the second portion P2. The second portion P2 uses the generated electrostatic attraction to hold the edge ring UR.

[0059] In one embodiment, the annular support surface extends at a position lower than the substrate support surface. In this case, the first portion P1 includes a side wall surface 111s that extends between the substrate support surface and the annular support surface. In this case, the edge ring LR (lower edge ring) may be disposed along the side wall surface 111s and on the annular support surface. The edge ring LR constitutes a part of the ring assembly 112. The edge ring LR may be formed of a conductive material such as silicon, silicon carbide, or tungsten. Alternatively, the edge ring LR may also be formed of an insulating material such as quartz. In this case, the edge ring UR is disposed on the edge ring LR. The annular support surface and the side wall surface 111s are protected by the edge ring LR.

[0060] AsFigure 3 As shown, the substrate support portion 11 may further include a cover ring CR and an insulating member IM. The insulating member IM is formed of an insulating material such as quartz and has a substantially cylindrical shape. The insulating member IM extends circumferentially around the central axis of the substrate support portion 11 so as to surround the base 1110 and the electrostatic chuck 1111. The cover ring CR has a substantially disc shape and is disposed on the insulating member IM so as to surround the edge ring UR.

[0061] The plasma processing apparatus 1 further includes a lifting mechanism 50. The lifting mechanism 50 includes a conductive ring 51, at least one rod 52, an actuator 53, and at least one connecting member 54.

[0062] The conductive ring 51 is formed of a metal or a conductive material such as aluminum and has a substantially ring shape. The conductive ring 51 extends circumferentially around the central axis of the substrate support portion 11 inside the insulating member IM so as to surround the base 1110 and the electrostatic chuck 1111. The conductive ring 51 is configured to be electrically coupled to the edge ring UR in a state of supporting the edge ring UR placed thereon. That is, the conductive ring 51 is configured to be electrically connected or capacitively coupled to the edge ring UR in a state of supporting the edge ring UR placed thereon. In Figure 3 this example, the conductive ring 51 is electrically connected to the edge ring UR in a state of supporting the edge ring UR placed thereon. In addition, the exposed area of the conductive ring 51 on the surface may be covered with a film resistant to plasma. This film may be formed of a material such as an alumina film or yttrium fluoride, or may be formed by a method such as anodic oxidation treatment or spraying.

[0063] At least one rod 52 extends vertically below the conductive ring 51. At least one rod 52 may have insulation. In this case, it is possible to suppress the inflow of an electrical bias into the actuator 53 via at least one rod 52. In one embodiment, the lifting mechanism 50 may include a plurality of rods 52 as at least one rod 52. The plurality of rods 52 are arranged circumferentially around the central axis of the substrate support portion 11. The plurality of rods 52 may be arranged at equal intervals in the circumferential direction.

[0064] The actuator 53 is disposed below at least one rod 52 and is connected to at least one rod 52. The actuator 53 is configured to be able to move the edge ring up and down via at least one rod 52 and the conductive ring 51. The actuator 53 may be, for example, a pneumatic or hydraulic cylinder or a motor.

[0065] At least one connecting member 54 provides an electrical connection between the conductive ring 51 and the base 1110 (or its conductive member). At least one connecting member 54 is configured to maintain this electrical connection as the conductive ring 51 moves. At least one connecting member 54 may be configured to deform as the conductive ring 51 moves. Further, in the case where the lifting mechanism 50 includes a plurality of rods 52, a plurality of connecting members 54 may be included as at least one connecting member 54.

[0066] In Figure 3 In the example shown, at least one connecting member 54 includes an upper portion 54a, a deformable portion 54b, and a lower portion 54c. The upper portion 54a, the deformable portion 54b, and the lower portion 54c are formed of a conductive material. The upper portion 54a is disposed directly below the conductive ring 51 and is fixed to the conductive ring 51. The upper portion 54a is electrically connected to the conductive ring 51. The lower portion 54c is disposed below the upper portion 54a and is fixed to the base 1110. The lower portion 54c is electrically connected to the base 1110.

[0067] The deformable portion 54b extends between the upper portion 54a and the lower portion 54c. The upper end of the deformable portion 54b is fixed to the upper portion 54a, and the lower end of the deformable portion 54b is fixed to the lower portion 54c. The deformable portion 54b is electrically connected to the upper portion 54a and the lower portion 54c. The deformable portion 54b can be Figure 3 a bellows as shown.

[0068] At least one rod 52 passes through the lower portion 54c, passes through the deformable portion 54b, and extends to the region directly below the upper portion 54a. When at least one rod 52 is moved upward by the actuator 53, the edge ring UR moves upward via the upper portion 54a and the conductive ring 51 (see Figure 23 ). In order to reduce the difference between the upper end position of the plasma sheath on the substrate W and the upper end position of the plasma sheath on the edge ring UR, the edge ring UR moves upward as its thickness decreases. In the plasma processing apparatus 1, even when the edge ring UR moves upward from the electrostatic chuck 1111, the electrical connection between the base 1110 and the edge ring UR can be maintained by the connecting member 54. In the plasma processing apparatus 1, the edge ring UR does not become electrically floating, so the edge ring UR can function to reduce the difference between the upper end position of the plasma sheath on the substrate W and the upper end position of the plasma sheath on the edge ring UR.

[0069] Alternatively, the connecting member 54 may be a cylindrical member having a plurality of slits formed in its side wall surface so as to be elastically deformable in its longitudinal direction. For example, the connecting member 54 may be a "Flexus" flexible body.

[0070] Hereinafter, refer to Figure 4 . Figure 4FIG. is a view showing a substrate support portion and a lifting mechanism according to another exemplary embodiment. Figure 4 The illustrated substrate support portion 11 and the lifting mechanism 50 can be employed in the plasma processing apparatus 1. Hereinafter, regarding Figure 4 the embodiment of Figure 3 it will be described from the perspective of differences from the

[0071] As Figure 4 shown, the lifting mechanism 50 can have a deformed portion 54b as a contact band instead of a bellows. The upper end of the deformed portion 54b can be fixed to the conductive ring 51. The lower end of the deformed portion 54b can be fixed to the base 1110. Figure 4 The illustrated deformed portion 54b has flexibility in the vertical direction. As Figure 4 shown, the deformed portion 54b can have a substantially arcuate shape bulging outward. In this case, the insulating member IM can provide a recess in which a part of the deformed portion 54b can be disposed.

[0072] Hereinafter, reference will be made to Figure 5 . Figure 5 FIG. is a view showing a substrate processing system according to an exemplary embodiment. Figure 5 The illustrated substrate processing system PS includes a transfer module TM, a plurality of processing modules PM1 to PM7 (a plurality of substrate processing modules), and a control unit MC. The substrate processing system PS may further include loading platforms LPa to LPd, containers FUa to FUd, a loading module LM, an aligner AN, a loading lock module LL1, a loading lock module LL2, and a storage module RSM (ring storage). In addition, the number of loading platforms, the number of containers, and the number of loading lock modules in the substrate processing system PS can be any number of one or more. In addition, the number of processing modules in the substrate processing system PS can be any number of two or more.

[0073] The loading platforms LPa to LPd are arranged along one edge of the loading module LM. The containers FUa to FUd are respectively mounted on the loading platforms LPa to LPd. The containers FUa to FUd are each, for example, a container called a FOUP (Front Opening Unified Pod). Each of the containers FUa to FUd is configured to be able to accommodate a substrate W therein.

[0074] The loading module LM has a transfer chamber. The pressure in the transfer chamber of the loading module LM is set to atmospheric pressure. The loading module LM has a transfer robot LMR. The transfer robot LMR is controlled by the control unit MC. The transfer robot LMR is configured to be able to transfer the substrate W via the transfer chamber of the loading module LM. The transfer robot LMR can transfer the substrate W between each of the containers FUa to FUd and the aligner AN, between the aligner AN and each of the loading lock modules LL1, LL2, and between each of the loading lock modules LL1, LL2 and each of the containers FUa to FUd. The aligner AN is connected to the loading module LM. The aligner AN is configured to be able to perform position adjustment (alignment) of the substrate W.

[0075] The loading lock module LL1 and the loading lock module LL2 are each connected between the transfer chamber of the loading module LM and the transfer chamber TC of the transfer module TM. The loading lock module LL1 and the loading lock module LL2 each provide a pre-pressure reduction chamber. A gate is provided between the pre-pressure reduction chamber of each of the loading lock module LL1 and the loading lock module LL2 and the transfer chamber of the loading module LM. In addition, a gate is provided between the pre-pressure reduction chamber of each of the loading lock module LL1 and the loading lock module LL2 and the transfer chamber TC of the transfer module TM.

[0076] The transfer module TM has a transfer chamber TC (vacuum transfer chamber) and a transfer robot TR. The transfer chamber TC is configured to be able to reduce the pressure in its internal space. The transfer robot TR includes a picker TP (end effector). The transfer robot TR may include at least two pickers TP. In the illustrated example, the transfer robot TR includes two pickers TP. One of the two pickers TP is disposed above the other. The transfer robot TR is configured to be able to transfer the substrate W disposed on any one of the two pickers TP via the transfer chamber TC. The transfer robot TR is controlled by the control unit MC.

[0077] Position detection sensors S11 and S12 may be provided in the transfer module TM. The position detection sensors S11 and S12 are provided on the transfer path for transferring the substrate W and the edge ring from the transfer module TM to the processing module PM1. The position detection sensors S11 and S12 are used to correct the positions of the substrate W and the edge ring transferred from the transfer module TM to the processing module PM1. The position detection sensors S11 and S12 are, for example, provided near the gate that separates the transfer module TM and the processing module PM1. The position detection sensors S11 and S12 are arranged such that the distance between them is smaller than the outer diameter of the substrate W and smaller than the inner diameter of the edge ring. Similarly to the position detection sensors S11 and S12, position detection sensors S21, S22, S31, S32, S41, S42, S51, S52, S61, S62, S71, and S72 may also be provided in the transfer module TM. The position detection sensors S21 and S22 are provided on the transfer path for transferring the substrate W and the edge ring from the transfer module TM to the processing module PM2. The position detection sensors S31 and S32 are provided on the transfer path for transferring the substrate W and the edge ring from the transfer module TM to the processing module PM3. The position detection sensors S41 and S42 are provided on the transfer path for transferring the substrate W and the edge ring from the transfer module TM to the processing module PM4. The position detection sensors S51 and S52 are provided on the transfer path for transferring the substrate W and the edge ring from the transfer module TM to the processing module PM5. The position detection sensors S61 and S62 are provided on the transfer path for transferring the substrate W and the edge ring from the transfer module TM to the processing module PM6. The position detection sensors S71 and S72 are provided on the transfer path for transferring the substrate W and the edge ring from the transfer module TM to the processing module PM7.

[0078] In one embodiment, the transfer robot TR is configured to be able to transfer the edge ring for the substrate support portion of any one of the plurality of processing modules PM1 to PM7. The edge ring is the edge ring UR or a ring set including the edge ring UR and the edge ring LR. The edge ring is transferred while being disposed on any one of the two pickers TP. Each picker TP has a sensor TS. The sensor TS is an optical sensor and is configured to be able to measure the position of a ring component such as the edge ring on the substrate support portion.

[0079] The processing modules PM1 to PM7 are each a device configured to perform dedicated substrate processing and have a processing chamber (substrate processing chamber). A gate is provided between the processing chamber and the transfer chamber TC. At least one of the processing modules PM1 to PM7 is the plasma processing device 1.

[0080] The storage module RSM (ring storage) is connected to the transfer chamber TC via a gate. The storage module RSM has a chamber and can store a plurality of edge rings therein.

[0081] The control unit MC is configured to be able to control each part of the substrate processing system PS. The control unit MC may be a computer including a processor, a storage device, an input device, a display device, etc. The control unit MC executes a control program stored in the storage device and controls each part of the substrate processing system PS based on recipe data stored in the storage device.

[0082] The plasma processing device 1 used as a processing module of the substrate processing system PS may include Figures 6 - 9 a substrate support portion 11 as shown in any of them. Figures 6 - 9 They are respectively diagrams showing a substrate support portion and a lifting mechanism of another exemplary embodiment. In Figures 6 - 9 each of the embodiments, the edge ring of the plasma processing device 1 can be transported by the transfer robot TR and replaced with a corresponding edge ring in the storage module RSM.

[0083] In Figure 6 the embodiment, the substrate support portion 11 provides a plurality of through holes penetrating therethrough in the vertical direction. The plurality of through holes of the substrate support portion 11 are arranged circumferentially around the central axis of the substrate support portion 11. The plurality of through holes of the substrate support portion 11 may be arranged at equal intervals. In addition, a plurality of through holes respectively aligned with the plurality of through holes of the substrate support portion 11 are formed in the edge ring LR.

[0084] In Figure 6 the embodiment, the edge ring UR can be lifted upward from the substrate support portion 11 by the lifting mechanism 60. The lifting mechanism 60 includes a plurality of lifting pins 61 and an actuator 62. The plurality of lifting pins 61 are respectively inserted into the plurality of through holes of the substrate support portion 11. The actuator 62 is connected to the plurality of lifting pins 61 and is configured to be able to move the plurality of lifting pins 61 up and down.

[0085] In a state where the upper ends of the plurality of lifting pins 61 are in contact with the edge ring UR, when the plurality of lifting pins 61 are moved upward by the actuator 62, the edge ring UR is lifted upward from the substrate support portion 11. In this state, the transfer robot TR moves the picker TP below the edge ring UR. Then, the plurality of lifting pins 61 move downward, whereby the edge ring UR is handed over to the picker TP. After that, the edge ring UR is transported by the transfer robot TR to the storage module RSM.

[0086] Then, the replacement edge ring UR is transported from the storage module RSM into the chamber 10 by the transfer robot TR. Then, the actuator 62 moves the plurality of lifting pins 61 upward, whereby the edge ring UR is handed over to the plurality of lifting pins 61. Then, the picker TP moves outside the chamber 10, and the plurality of lifting pins 61 move downward. Thus, the replacement edge ring UR is disposed on the substrate support portion 11.

[0087] In Figure 7 the embodiment, the substrate support portion 11 provides a plurality of through holes penetrating therethrough in the vertical direction. The plurality of through holes of the substrate support portion 11 are arranged circumferentially around the central axis of the substrate support portion 11. The plurality of through holes of the substrate support portion 11 may be arranged at equal intervals in the circumferential direction. No plurality of through holes are formed in the edge ring LR that are respectively aligned with the plurality of through holes of the substrate support portion 11.

[0088] In Figure 7 the embodiment, the ring group including the upper edge ring UR and the lower edge ring LR can be lifted upward from the substrate support portion 11 by the lifting mechanism 70. The lifting mechanism 70 includes a plurality of lifting pins 71 and an actuator 72. The plurality of lifting pins 71 are respectively inserted into the plurality of through holes of the substrate support portion 11. The actuator 72 is connected to the plurality of lifting pins 71 and is configured to be able to move the plurality of lifting pins 71 up and down.

[0089] In a state where the upper ends of the plurality of lifting pins 71 are in contact with the edge ring LR, when the plurality of lifting pins 71 are moved upward by the actuator 72, the ring group is lifted upward from the substrate support portion 11. In this state, the transfer robot TR moves the picker TP to below the ring group. Then, the plurality of lifting pins 71 move downward, whereby the ring group is transferred to the picker TP. After that, the ring group is transported by the transfer robot TR to the storage module RSM.

[0090] Then, the replacement ring group is transported from the storage module RSM into the chamber 10 by the transfer robot TR. Next, the actuator 72 moves the plurality of lifting pins 71 upward, whereby the ring group is transferred to the plurality of lifting pins 71. Then, the picker TP moves outside the chamber 10, and the plurality of lifting pins 71 move downward. Thereby, the replacement ring group is disposed on the substrate support portion 11.

[0091] In Figure 8 the embodiment, the conductive ring 51 extends to the area on the edge ring LR to support the upper edge ring UR by its upper end inner edge portion. In Figure 8 the embodiment, the outer ring OR is disposed on the conductive ring 51 so as to surround the upper edge ring UR. The outer ring OR can be formed of an insulating material such as quartz. In Figure 8 the embodiment, similar to Figure 6 the embodiment, the substrate support portion 11 provides a plurality of through holes penetrating therethrough. The plurality of through holes of the substrate support portion 11 are arranged circumferentially around the central axis of the substrate support portion 11. The plurality of through holes of the substrate support portion 11 may be arranged at equal intervals in the circumferential direction. In addition, a plurality of through holes are formed in the edge ring LR that are respectively aligned with the plurality of through holes of the substrate support portion 11.

[0092] Figure 8In the embodiment, the operations of the lifting mechanism 60 for replacing the edge ring UR and the transfer robot TR are the same as those in Figure 6 In the embodiment, the operations of the lifting mechanism 60 for replacing the edge ring UR and the transfer robot TR are the same as those in

[0093] In Figure 9 In the embodiment, the edge ring LR has an outer diameter smaller than that of the edge ring UR. The edge ring UR is disposed on the edge ring LR such that its outer edge portion protrudes radially outward with respect to the edge ring LR. The conductive ring 51 supports the outer edge portion of the edge ring UR by its upper end inner edge portion. In Figure 9 In the embodiment, the outer ring OR is disposed on the conductive ring 51 so as to surround the edge ring UR. The outer ring OR may be formed of an insulating material such as quartz. Further, in Figure 9 In the embodiment, another outer ring BOR is disposed below the upper end portion of the conductive ring 51 so as to surround the edge ring LR. The outer ring BOR may be formed of an insulating material such as quartz.

[0094] In Figure 9 In the embodiment, the substrate support portion 11 also provides a plurality of through holes penetrating therethrough, in the same manner as in Figure 7 In the embodiment. The plurality of through holes of the substrate support portion 11 are arranged circumferentially around the central axis of the substrate support portion 11. The plurality of through holes of the substrate support portion 11 may be arranged at equal intervals in the circumferential direction. No plurality of through holes are formed in the edge ring LR that are respectively aligned with the plurality of through holes of the substrate support portion 11.

[0095] Figure 9 In the embodiment, the operations of the lifting mechanism 70 for replacing the edge ring and the transfer robot TR are the same as those in Figure 7 In the embodiment, the operations of the lifting mechanism 70 for replacing the edge ring and the transfer robot TR are the same as those in

[0096] In addition, in another exemplary embodiment, the plasma processing apparatus 1 may also be configured to be able to selectively perform only the replacement of the edge ring UR or the replacement of the above ring set. For example, the plasma processing apparatus 1 may have both the lifting mechanism 60 and the lifting mechanism 70. In this case, the plurality of lifting pins 61 and the plurality of lifting pins 71 are alternately arranged in the circumferential direction. No through holes are formed in the edge ring LR above each of the plurality of lifting pins 71. In this case, it is possible to selectively use the lifting mechanism 60 to replace only the Figure 6 shown edge ring UR, or use the lifting mechanism 70 to replace the Figure 6 shown ring set including the edge ring UR and the edge ring LR. Or, it is possible to selectively use the lifting mechanism 60 to replace only the Figure 9 shown edge ring UR, or use the lifting mechanism 70 to replace the Figure 9A ring group including an edge ring UR and an edge ring LR as shown.

[0097] Hereinafter, a structural example of a capacitively coupled plasma processing apparatus, which is another example of the plasma processing apparatus 1, will be described. Figure 10 It is a diagram for explaining a structural example of a capacitively coupled plasma processing apparatus. In addition, Figure 10 The plasma processing apparatus 1 as shown includes a substrate support portion 11 and a lifting mechanism 50 of any one of the above various exemplary embodiments of the plasma processing apparatus. Figure 10 The plasma processing apparatus 1 as shown may include the above-described lifting mechanism 60 and / or lifting mechanism 70. Additionally, Figure 10 The plasma processing apparatus 1 as shown can be used as a processing module in the substrate processing system PS. Hereinafter, regarding Figure 10 the capacitively coupled plasma processing apparatus 1 as shown, it will be described from the perspective of differences from Figure 2 the inductively coupled plasma processing apparatus 1 as shown.

[0098] In Figure 10 the plasma processing apparatus 1 as shown, the gas introduction portion includes a shower head 13A. The shower head 13A is disposed above the substrate support portion 11. In one embodiment, the shower head 13A constitutes at least a part of the ceiling of the plasma processing chamber 10. The plasma processing chamber 10 has a plasma processing space 10s defined by the shower head 13A, the side wall 10a of the plasma processing chamber 10, and the substrate support portion 11. The plasma processing chamber 10 is grounded. The shower head 13A and the substrate support portion 11 are electrically insulated from the housing of the plasma processing chamber 10.

[0099] The shower head 13A is configured to be able to introduce at least one processing gas from the gas supply portion 20 into the plasma processing space 10s. The shower head 13A has at least one gas supply port 13Aa, at least one gas diffusion chamber 13Ab, and a plurality of gas introduction ports 13Ac. The processing gas supplied to the gas supply port 13Aa is introduced into the plasma processing space 10s from the plurality of gas introduction ports 13Ac through the gas diffusion chamber 13Ab. Additionally, the shower head 13A includes at least one upper electrode. In addition, the gas introduction portion may include, in addition to the shower head 13A, one or more side gas injectors (SGI) installed in one or more openings formed in the side wall 10a.

[0100] In Figure 10In the plasma processing apparatus 1 shown, the susceptor 1110 (or its conductive member), i.e., the lower electrode, is electrically coupled to a high-frequency power source and / or at least one bias power source. The high-frequency power source is the first RF generation unit 31a, which constitutes the plasma generation unit 12. The at least one bias power source includes the second RF generation unit 31b and / or the bias DC generation unit 32a (i.e., the first DC generation unit). The at least one bias power source is configured to be able to generate an electrical bias to attract ions from the plasma to the substrate W on the substrate support portion 11. The electrical bias includes the above-mentioned bias RF signal and / or a sequence of voltage pulses.

[0101] In Figure 10 In the plasma processing apparatus 1 shown, the DC power source 32 may further include a second DC generation unit 32b in addition to including the bias DC generation unit 32a, i.e., the first DC generation unit 32a. In one embodiment, the first DC generation unit 32a is connected to at least one lower electrode and is configured to be able to generate a first DC signal. The generated first DC signal is applied to at least one lower electrode. In one embodiment, the second DC generation unit 32b is connected to at least one upper electrode and is configured to be able to generate a second DC signal. The generated second DC signal is applied to at least one upper electrode.

[0102] In various embodiments, in addition to the first DC signal, the second DC signal may also be pulsed. In this case, a sequence of voltage pulses is applied to at least one lower electrode and / or at least one upper electrode. The voltage pulses may have a pulse waveform such as rectangular, trapezoidal, triangular, or a combination thereof. In one embodiment, a waveform generation unit for generating a sequence of voltage pulses from a DC signal is connected between the first DC generation unit 32a and at least one lower electrode. Thus, the first DC generation unit 32a and the waveform generation unit constitute a voltage pulse generation unit. In the case where the second DC generation unit 32b and the waveform generation unit constitute a voltage pulse generation unit, the voltage pulse generation unit is connected to at least one upper electrode. The voltage pulses may have a positive polarity or a negative polarity. Additionally, 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. Furthermore, the first and second DC generation units 32a, 32b may be provided together with the RF power source 31, or the first DC generation unit 32a may be provided in place of the second RF generation unit 31b.

[0103] Hereinafter, with reference to Figure 11 . Figure 11 FIG. is a diagram showing a susceptor and a lifting mechanism according to another exemplary embodiment. Figure 11 The susceptor 11 and the lifting mechanism 50 shown can be employed in the above-mentioned inductively coupled plasma processing apparatus 1 or capacitively coupled plasma processing apparatus 1. Hereinafter, regarding Figure 11The substrate support portion 11 and the lifting mechanism 50 shown will be described from the perspective of differences from Figure 3 the substrate support portion 11 and the lifting mechanism 50 shown.

[0104] Figure 11 The lifting mechanism 50 shown and Figure 3 the lifting mechanism 50 shown can, in the same manner, electrically couple (e.g., conduct) the conductive ring 51 and the edge ring UR while the conductive ring 51 is supported by the conductive ring 51. That is, in Figure 11 the lifting mechanism 50 shown, it is also possible to form a first state in which the edge ring UR and the base 1110 are electrically coupled to each other (e.g., a conductive state between the edge ring UR and the base 1110). In addition, Figure 11 the lifting mechanism 50 shown can lower the conductive ring 51 downward via the rod 52 by using the actuator 53 to separate the conductive ring 51 from the edge ring UR. That is, in Figure 11 the lifting mechanism 50 shown, by separating the conductive ring 51 from the edge ring UR, it is possible to form a second state in which the edge ring UR and the base 1110 are electrically separated from each other (e.g., a non-conductive state between the edge ring UR and the base 1110). Therefore, Figure 11 the lifting mechanism 50 shown constitutes a switch that can switch between the first state and the second state.

[0105] Hereinafter, refer to Figure 12 . Figure 12 is a diagram showing a substrate support portion and a lifting mechanism of another exemplary embodiment. Figure 12 The substrate support portion 11 and the lifting mechanism 50 shown can be adopted in the above-described inductively coupled plasma processing apparatus 1 or capacitively coupled plasma processing apparatus 1. Hereinafter, regarding Figure 12 the substrate support portion 11 and the lifting mechanism 50 shown, it will be described from the perspective of differences from Figure 4 the substrate support portion 11 and the lifting mechanism 50 shown.

[0106] In the plasma processing apparatus 1 including Figure 12 the lifting mechanism 50 shown, a switch 56 is further included. The switch 56 can be a part of the lifting mechanism 50. The switch 56 includes a switching element and is connected between the connecting member 54 and the conductive ring 51 or between the connecting member 54 and the base 1110. When the switching element of the switch 56 is in the ON state (closed state), it is possible to form a first state in which the edge ring UR and the base 1110 are electrically coupled to each other (e.g., a conductive state between the edge ring UR and the base 1110). When the switching element of the switch 56 is in the OFF state (open state), it is possible to form a second state in which the edge ring UR and the base 1110 are electrically separated from each other (e.g., a non-conductive state between the edge ring UR and the base 1110).

[0107] Hereinafter, with reference to Figure 13 . Figure 13 FIG. is a view showing a substrate support portion and a lifting mechanism according to another exemplary embodiment. Figure 13 The substrate support portion 11 and the lifting mechanism 50 shown can be adopted in the inductively coupled plasma processing apparatus 1 or the capacitively coupled plasma processing apparatus 1 described above. Hereinafter, regarding Figure 13 the substrate support portion 11 and the lifting mechanism 50 shown, from the perspective of differences from Figure 6 the substrate support portion 11 and the lifting mechanism 50 shown.

[0108] Including Figure 13 In the plasma processing apparatus 1 including the lifting mechanism 50 shown, as a switch configured to be able to switch between the above-described first state and second state, a lifting mechanism 60 is included. In the lifting mechanism 60, all the lifting pins 61 are formed of an insulating material. When the lifting mechanism 60 positions all the lifting pins 61 such that the edge ring UR is supported on the conductive ring 51 and electrically connected to the conductive ring 51, a first state (for example, a conductive state between the edge ring UR and the base 1110) can be formed. When the lifting mechanism 60 lifts the edge ring UR upward from the conductive ring 51 and separates it from the conductive ring 51, a second state (for example, a non-conductive state between the edge ring UR and the base 1110) can be formed.

[0109] Using the switch described with reference to Figures 11 - 13 , the above-described first state and second state can be switched as needed. The switch can be controlled by the control unit 2. Hereinafter, with reference to Figures 14 - 18 , a plasma processing method performed in the plasma processing apparatus 1 including Figures 11 - 13 the switch shown will be described.

[0110] With reference to Figure 14 and Figure 15 (a) of. Figure 14 FIG. is a flowchart showing a plasma processing method according to an exemplary embodiment. Figure 15 (a) of FIG. is a view showing an example of a camera device used in conjunction with plasma processing apparatuses according to various exemplary embodiments. In Figure 14 the plasma processing method shown (hereinafter referred to as "method MT"), the camera device 80 shown in Figure 15 (a) of FIG. can be used. The camera device 80 can be disposed in the aligner AN. The camera device 80 can be disposed at any location as long as an image of the substrate W can be acquired.

[0111] Method MT is performed with the substrate W placed on the substrate support portion 11. Method MT starts from step STa. In step STa, the control unit 2 reads the recipe.

[0112] In the next step STJ, the control unit 2 determines whether electrical coupling (e.g., conduction) between the edge ring UR and the base 1110 is required. In step STJ, the control unit 2 may determine that electrical coupling between the edge ring UR and the base 1110 is required when it is determined that the density of the plasma on the edge ring UR should be increased. On the other hand, in step STJ, the control unit 2 may determine that electrical coupling between the edge ring UR and the base 1110 is not required when it is determined that the density of the plasma on the edge ring UR should not be increased.

[0113] When the control unit 2 determines that the density of the plasma on the edge ring UR should be increased, in step STb, the control unit 2 controls the switch to form a first state (e.g., a conductive state between the edge ring UR and the base 1110). On the other hand, when the control unit 2 determines that the density of the plasma on the edge ring UR should not be increased, in step STc, the control unit 2 controls the switch to form a second state (e.g., a non-conductive state between the edge ring UR and the base 1110).

[0114] Next, step STd is performed. In step STd, the control unit 2 controls each part of the plasma processing apparatus 1 to perform plasma processing according to the above recipe. When performing step STd, when the edge ring UR and the base 1110 are electrically coupled to each other (e.g., when they are conductive to each other), due to the action of the generated source RF signal and / or the electrical bias supplied from the base 1110 to the edge ring UR via the conductive ring 51, the plasma density on the edge ring UR increases.

[0115] The control unit 2 may obtain an image of the upper surface of the substrate W that has been previously processed in the plasma processing apparatus 1 using the same recipe compared to the substrate W being placed on the substrate support portion 11 from the imaging device 80 in order to make the determination in step STJ. The control unit 2 may determine whether the density of the plasma on the edge ring UR should be increased based on this image. In one embodiment, in step STd, a plurality of holes may be formed in the substrate W by plasma processing based on the recipe. In this case, when the control unit 2 determines in step STJ that the roundness of the holes on the upper surface of the substrate W in the edge region of the substrate W is below the threshold based on the image obtained from the imaging device 80, step STb is performed. On the other hand, when the control unit 2 determines in step STJ that the roundness is greater than the threshold based on the image obtained from the imaging device 80, step STc is performed. Here, the roundness may be the ratio of the minimum width to the maximum width of the holes on the upper surface of the substrate W in the edge region of the substrate W.

[0116] Hereinafter, refer to Figure 14 and Figure 15 (b) of Figure 15 (b) of Figure 15 is a diagram showing an example of a measuring instrument used with the plasma processing apparatus of various exemplary embodiments. In method MT, the measuring instrument 82 shown in

[0117] (b) can also be used. The measuring instrument 82 is mounted on the picker TP. The measuring instrument 82 is configured to be able to measure the thickness of the deposit on the edge ring UR. The measuring instrument 82 may include an image sensor that acquires an image of the edge ring UR, or may include other optical sensors configured to be able to measure the thickness of the deposit on the edge ring UR. 2 The control unit 2 can determine whether the density of the plasma on the edge ring UR should be increased based on the thickness of the deposit on the edge ring UR measured by the measuring instrument 82. In one embodiment, in step STd, the inside of the chamber 10 is cleaned by plasma processing based on a recipe. In this case, when the control unit 2 determines in step STJ that the thickness of the deposit on the edge ring UR measured by the measuring instrument 82 is equal to or greater than the threshold value, step STb is performed. On the other hand, when the control unit 2 determines in step STJ that the thickness of the deposit on the edge ring UR measured by the measuring instrument 82 is less than the threshold value, step STc is performed. When step STd is performed after step STb, the density of the plasma on the edge ring UR becomes high, and the removal of the deposit on the edge ring UR can be promoted. Further, in the cleaning in step STd, a cleaning gas containing an oxygen-containing gas such as O

[0118] Hereinafter, refer to Figure 16 . Figure 16 is a flowchart showing another exemplary plasma processing method. Figure 16 The plasma processing method (hereinafter referred to as "method MTA") shown in

[0119] In the next step STAd, the control unit 2 selects the first step specified within the scenario. The scenario includes a plurality of steps, and for each step within the scenario, setting information related to the electrical coupling (e.g., conduction) between the edge ring UR and the base 1110 is specified. The setting information is information specifying the above-described first state (e.g., conduction state) or second state (e.g., non-conduction state).

[0120] In the next step STAJ, the control unit 2 determines whether electrical coupling between the edge ring UR and the base 1110 is required based on the setting information specified for the selected step within the scenario. When the control unit 2 determines in step STAJ that electrical coupling between the edge ring UR and the base 1110 is required, it performs step STb in the same manner as the method MT. On the other hand, when the control unit 2 determines in step STAJ that electrical coupling between the edge ring UR and the base 1110 is not required, it performs step STc in the same manner as the method MT. Then, the control unit 2 controls each part of the plasma processing apparatus 1 to perform the processing of the step selected in step STAe.

[0121] In the next step STAJb, the control unit 2 determines whether all the steps included in the scenario have ended. When the control unit 2 determines that not all the steps have ended, it selects the next step included in the scenario in step STAf and continues the processing starting from step STAJ. On the other hand, when the control unit 2 determines in step STAJb that all the steps have ended, it ends the method MTA.

[0122] Hereinafter, with reference to Figure 17 and Figure 18 . Figure 17 is a flowchart showing a plasma processing method according to another exemplary embodiment. Figure 18 is a diagram showing an example of a measuring device used with a plasma processing apparatus according to various exemplary embodiments. In Figure 17 the plasma processing method shown (hereinafter referred to as "method MTB"), the measuring device 200 shown in Figure 18 can be used.

[0123] The measuring device 200 includes a condenser lens 202, an optical fiber 204, a light source 206, a light detector 208, and an arithmetic unit 210. The condenser lens 202 is disposed above the top 10U of the chamber 10 and is optically coupled to the substrate W on the substrate support portion 11 via the optical window of the top 10U. Further, the top 10U is a dielectric window 101 or a shower head 13A.

[0124] The condenser lens 202 is optically connected to the light source 206 and the optical detector 208 (polychromator) via the optical fiber 204. The light source 206 emits light Ls. The light Ls emitted from the light source 206 is irradiated onto the substrate W via the optical fiber 204 and the condenser lens 202. The light Ls is reflected at a plurality of portions within the substrate W at different height positions, generating interference light Li. The interference light Li is input to the optical detector 208 via the condenser lens 202 and the optical fiber 204. The optical detector 208 is configured to be able to detect the light intensity of the interference light Li. The arithmetic unit 210 is configured to be able to measure the etching depth of the substrate W based on the change in the light intensity of the interference light Li detected by the optical detector 208. The light intensity of the interference light Li changes periodically according to the etching depth of the substrate W. Therefore, the arithmetic unit 210 can determine the etching depth of the substrate W based on the change in the light intensity of the interference light Li.

[0125] As Figure 17 shown, the method MTB starts with the same step STa as the step STa of the method MT. The method MTB is performed in a state where the substrate W is placed on the substrate support portion 11. In the next step SBd, the control unit 2 starts the plasma processing according to the plan. Specifically, the plasma etching of the substrate W is started. The control unit 2 controls each part of the plasma processing apparatus 1 according to the plan during the plasma etching. In addition, at the start of the plasma etching in the step STBd, a second state (for example, a non-conductive state between the edge ring UR and the base 1110) is formed.

[0126] The steps STBJ to STBJb are performed during the plasma etching started in the step STBd. In the step STBJ, the control unit 2 determines whether electrical coupling (for example, conduction) between the edge ring UR and the base 1110 is required. Specifically, the control unit 2 determines whether the etching depth measured by the measurer 200 has reached the threshold value. When the control unit 2 determines that the etching depth has reached the threshold value, it performs the step STb. On the other hand, when the control unit 2 determines that the etching depth has not reached the threshold value, it performs the step STc and maintains the second state (for example, non-conductive state).

[0127] In the next step STBJb, it is determined whether to end the plasma etching, which is the processing started in the step STd. If the plasma etching is not ended, the processing from the step STBJ is repeated. On the other hand, when the plasma etching is ended, the control unit 2 ends the method MTB.

[0128] Hereinafter, referring to Figure 19 . Figure 19FIG. is a diagram showing an edge ring and a conductive ring of another exemplary embodiment. As described above, in various exemplary embodiments, the conductive ring 51 may be in contact with the edge ring UR and conduct electricity with the edge ring UR, thereby forming a conductive state between the edge ring UR and the base 1110 as a first state. Alternatively, as Figure 19 shown, the conductive ring 51 may also be conducted with the edge ring UR via the component 51c, thereby forming a conductive state between the edge ring UR and the base 1110 as a first state. The component 51c is formed of a conductive material such as metal. In the case of forming the first state, the component 51c is clamped between the edge ring UR and the conductive ring 51. The component 51c may have elasticity. The component 51c may be an inclined wound helical spring.

[0129] Hereinafter, refer to Figure 20 . Figure 20 FIG. is a diagram showing an edge ring and a conductive ring of another exemplary embodiment. The conductive ring 51 may form a first state by capacitive coupling with the edge ring UR. As Figure 20 shown, the conductive ring 51 may include a dielectric region 51f on its upper surface. In this case, the conductive ring 51 is capacitively coupled to the edge ring UR while supporting the edge ring UR placed on the dielectric region 51f. The dielectric region 51f may be a film formed of a dielectric material. The dielectric region 51f may cover the surface of the conductive ring 51. The dielectric region 51f may be formed by spraying a material such as yttrium oxide.

[0130] Hereinafter, refer to Figure 21 . Figure 21 FIG. is a diagram showing a substrate support portion and a lifting mechanism of another exemplary embodiment. In the above various exemplary embodiments, the edge ring UR and the edge ring LR may have the Figure 21 structure shown. As Figure 21 shown, the edge ring LR includes an inner peripheral portion LRi, an intermediate portion LRm, and an outer peripheral portion LRo. The inner peripheral portion LRi is annular and is arranged along the side wall surface 111s on the ring support surface. The edge region of the substrate W is located above the inner peripheral portion LRi. The outer peripheral portion LRo is annular and extends radially outside with respect to the inner peripheral portion LRi. The edge ring UR is arranged on the outer peripheral portion LRo. The intermediate portion LRm is annular and extends between the inner peripheral portion LRi and the outer peripheral portion LRo. The intermediate portion LRm is located between the edge of the substrate W on the substrate support surface and the inner peripheral surface of the edge ring UR. The position of the upper surface of the intermediate portion LRm in the height direction is higher than the position of the upper surface of the inner peripheral portion LRi in the height direction and the position of the upper surface of the outer peripheral portion LRo in the height direction. The intermediate portion LRm may have a thickness larger than the thickness of the inner peripheral portion LRi and the thickness of the outer peripheral portion LRo.

[0131] When the edge ring UR is disposed in contact with the edge ring LR on the edge ring LR, the edge ring UR exchanges heat with the base 1110 via the edge ring LR and the electrostatic chuck 1111. On the other hand, when the edge ring UR is lifted upward relative to the edge ring LR, the temperature of the edge ring UR may rise. Using the intermediate portion LRm, as Figure 21 shown, the inner peripheral surface of the edge ring UR is spaced apart from the edge of the substrate W by a distance D in the radial direction. Therefore, even if the temperature of the edge ring UR rises, an increase in the temperature of the edge region of the substrate W can be suppressed. Further, when using Figure 21 the edge ring UR shown, the difference between the upper end position of the plasma sheath on the substrate W and the upper end position of the plasma sheath on the edge ring UR can also be reduced. As a result, ions can be vertically supplied to the edge region of the substrate W, and recesses such as holes can be vertically formed in the edge region of the substrate W. Further, the distance D may be 10 mm or less, may be 6 mm or less, or may be approximately 6 mm.

[0132] The results of experiments conducted to evaluate Figure 3 and Figure 21 each embodiment will be described below. In the experiment, a plasma etching of a silicon-containing film on a sample substrate was performed using the plasma processing apparatus 1 shown in Figure 10 , and the angle of the holes formed in the silicon-containing film was determined. The angle of the hole is 90° when the hole extends in the thickness direction of the sample substrate, i.e., in the vertical direction, is less than 90° when the hole is inclined outward from the sample substrate, and is greater than 90° when the hole is inclined toward the center of the sample substrate.

[0133] Figure 22 is a coordinate diagram showing the results of the experiment. In Figure 22 , the horizontal axis represents the driving amount of the conductive ring 51. In the state where the edge ring UR is disposed in contact with the edge ring LR on the edge ring LR, the driving amount is 0. As the edge ring UR is lifted upward from the edge ring LR and the distance in the vertical direction between the edge ring UR and the edge ring LR increases, the driving amount increases. In Figure 22 , the vertical axis represents the angle of the hole. In Figure 22 , the rectangular plotted points are the angles of the holes obtained when using the unconsumed edge ring UR and with a driving amount of 0 in the plasma processing apparatus 1 having the structure shown in Figure 3 . In Figure 22 , the circular plotted points are the angles of the holes obtained when using the edge ring UR having a thickness 1 mm smaller than the unconsumed edge ring UR in the plasma processing apparatus 1 having the structure shown in Figure 3 . In Figure 22 , the triangular plotted points are in the plasma processing apparatus 1 having the structure shown in Figure 21In the plasma processing apparatus 1 having the structure shown, the angle of the hole obtained when using an edge ring UR having a thickness 1 mm smaller than that of the unconsumed edge ring UR and having a distance D of 6 mm. As Figure 22 shown, it can be confirmed that when using the Figure 21 structure, similar to the case of using the Figure 3 structure shown, the angle of the hole can be adjusted according to the driving amount. In addition, adopting the Figure 21 structure, compared with the case of using the Figure 3 structure, the increase amount of the hole angle corresponding to the increase in the driving amount becomes smaller. From this, it can be confirmed that adopting the Figure 21 structure can obtain a high control resolution of the hole angle.

[0134] As described above, various exemplary embodiments have been described, but are not limited to the above exemplary embodiments, and various additions, omissions, substitutions, and changes can also be made. In addition, elements in different embodiments can be combined to form other embodiments.

[0135] For example, any one of the above containers FUa to FUd can be used as the storage module RSM.

[0136] Here, various exemplary embodiments included in the present invention are described in the following [E1] to [E19].

[0137] [E1]

[0138] A plasma processing apparatus, comprising:

[0139] a chamber;

[0140] a substrate support portion disposed in the above chamber;

[0141] a conductive edge ring disposed so as to surround a substrate on the above substrate support portion;

[0142] a lifting mechanism configured to be able to move the above edge ring up and down;

[0143] a plasma generation portion including a high-frequency power source, configured to be able to generate plasma in the above chamber; and

[0144] a bias power source configured to be able to generate an electrical bias to attract ions from the above plasma to the above substrate on the above substrate support portion,

[0145] The above substrate support portion includes:

[0146] a susceptor electrically coupled to the above bias power source and / or the above high-frequency power source; and

[0147] an electrostatic chuck on the susceptor,

[0148] The lifting mechanism described above includes:

[0149] A conductive ring that can be electrically coupled to the edge ring while supporting the edge ring placed thereon;

[0150] A rod that extends vertically below the conductive ring;

[0151] An actuator configured to be able to move the edge ring up and down via the rod and the conductive ring; and

[0152] A connecting component that provides electrical connection between the conductive ring and the base, and is configured to maintain the electrical connection as the conductive ring moves.

[0153] [E2]

[0154] The plasma processing apparatus according to E1, wherein

[0155] The connecting component can be deformed as the conductive ring moves.

[0156] [E3]

[0157] The plasma processing apparatus according to E2, wherein

[0158] The connecting component includes a bellows, a contact strip, or a cylindrical component, and the cylindrical component is formed with a plurality of slits on its side wall surface so as to be elastically deformable in its longitudinal direction.

[0159] [E4]

[0160] The plasma processing apparatus according to any one of E1 to E3, wherein

[0161] The rod has insulation.

[0162] [E5]

[0163] The plasma processing apparatus according to any one of E1 to E4, wherein

[0164] The exposed area of the conductive ring on the surface is covered with a film resistant to the plasma.

[0165] [E6]

[0166] The plasma processing apparatus according to any one of E1 to E5, wherein

[0167] The edge ring is an upper edge ring,

[0168] The plasma processing apparatus further includes a lower edge ring, and the upper edge ring is disposed above the lower edge ring.

[0169] The above-mentioned electrostatic chuck includes:

[0170] a first part having a substrate support surface; and

[0171] a second part extending outside the above-mentioned first part, which has a ring support surface extending at a position lower than the above-mentioned substrate support surface,

[0172] The above-mentioned first part includes a side wall surface extending between the above-mentioned substrate support surface and the above-mentioned ring support surface,

[0173] The above-mentioned lower edge ring is arranged on the above-mentioned ring support surface along the above-mentioned side wall surface.

[0174] [E7]

[0175] The plasma processing apparatus according to E6, wherein,

[0176] The above-mentioned lower edge ring includes:

[0177] an inner peripheral part arranged along the above-mentioned side wall surface;

[0178] an outer peripheral part extending radially outside the above-mentioned inner peripheral part, and the above-mentioned upper edge ring is arranged above the above-mentioned outer peripheral part; and

[0179] an intermediate part extending between the above-mentioned inner peripheral part and the above-mentioned outer peripheral part, and the above-mentioned intermediate part is located between the edge of the substrate on the above-mentioned substrate support surface and the inner peripheral surface of the above-mentioned upper edge ring.

[0180] [E8]

[0181] The plasma processing apparatus according to E6 or E7, wherein,

[0182] The above-mentioned lower edge ring has conductivity.

[0183] [E9]

[0184] The plasma processing apparatus according to E6 or E7, wherein,

[0185] The above-mentioned lower edge ring has insulation.

[0186] [E10]

[0187] The plasma processing apparatus according to any one of E6 to E9, wherein,

[0188] It further includes another lifting mechanism, and the above-mentioned another lifting mechanism is configured to be able to lift the above-mentioned upper edge ring or a ring group including the above-mentioned upper edge ring and the above-mentioned lower edge ring from the above-mentioned electrostatic chuck.

[0189] [E11]

[0190] The plasma processing apparatus according to any one of E1 to E10, wherein,

[0191] It further includes a switcher configured to be able to switch between a first state in which the edge ring and the base are electrically coupled to each other and a second state in which the edge ring and the base are electrically separated from each other.

[0192] [E12]

[0193] The plasma processing apparatus according to E11, wherein,

[0194] The lifting mechanism is the switcher configured to be able to lower the conductive ring by the actuator to separate the conductive ring from the edge ring, thereby forming the second state.

[0195] [E13]

[0196] The plasma processing apparatus according to E11, wherein,

[0197] The switcher includes a switching element connected between the connecting member and the conductive ring or between the connecting member and the base.

[0198] [E14]

[0199] The plasma processing apparatus according to E11, wherein,

[0200] The switcher includes another lifting mechanism configured to be able to form the second state by lifting the edge ring from the conductive ring.

[0201] [E15]

[0202] The plasma processing apparatus according to E11, wherein,

[0203] It further includes a control unit configured to be able to control the switcher to form the first state or the second state according to the read scenario.

[0204] [E16]

[0205] The plasma processing apparatus according to E11, further including:

[0206] A measurer configured to be able to measure the etching depth of the substrate on the substrate support portion; and

[0207] A control unit configured to be able to control the switcher to switch from the second state to the first state when the etching depth measured by the measurer reaches a threshold value.

[0208] [E17]

[0209] A substrate processing system, comprising:

[0210] The plasma processing apparatus described in E10;

[0211] A transfer module, which includes a transfer chamber and a transfer robot connected to the plasma processing apparatus;

[0212] A ring storage, which is configured to be able to store the upper edge ring or the upper edge ring and the ring group therein; and

[0213] A control unit

[0214] The control unit is configured to be able to control the other lifting mechanism and the transfer robot, and via the transfer chamber, replace the upper edge ring or the ring group in the chamber of the plasma processing apparatus with the upper edge ring or the ring group in the chamber.

[0215] [E18]

[0216] A substrate processing system, comprising:

[0217] The plasma processing apparatus described in E11;

[0218] An imaging device, which is configured to be able to acquire an image of a substrate etched by the plasma processing apparatus; and

[0219] A control unit

[0220] The control unit is configured to be able to control the switch to form the first state when etching the substrate subsequently in the plasma processing apparatus if it is determined from the image of the previously processed substrate that the roundness of the holes in the edge region of the substrate is below a threshold.

[0221] [E19]

[0222] A substrate processing system, comprising:

[0223] The plasma processing apparatus described in E11;

[0224] A measuring device, which is configured to be able to measure the thickness of the deposits on the edge ring; and

[0225] A control unit

[0226] The control unit is configured to be able to control the switch during the cleaning process in the chamber to form the second state when the thickness of the deposits is less than the threshold, and form the first state when the thickness of the deposits is above the threshold.

[0227] As can be seen from the above description, various embodiments of the present invention are described in this specification for illustrative purposes, and various changes can be made without departing from the scope and gist of the present invention. Therefore, the various embodiments disclosed in this specification are not intended to be limiting, and the true scope and gist are represented by the claimed technical solutions.

[0228] Description of Reference Numerals

[0229] 1... Plasma processing apparatus, 10... Chamber, 11... Substrate support portion, 12... Plasma generation portion, 1110... Base, 1111... Electrostatic chuck, 50... Lifting mechanism, 51... Conductive ring, 52... Rod, 53... Actuator, 54... Connecting member, PS... Substrate processing system, TM... Conveying module, RSM... Storage module, MC... Control unit.

Claims

1. A plasma processing device, characterized in that: include: Chamber; a substrate support portion disposed in the chamber; an edge ring having electrical conductivity and arranged to surround the substrate on the substrate support; A lifting mechanism configured to move the edge ring up and down; a plasma generating unit including a high frequency power source, configured to generate plasma in the chamber; and a bias power supply configured to generate an electrical bias to attract ions from the plasma to the substrate on the substrate support, The substrate support portion comprises: a base electrically coupled to the bias power supply and / or the high frequency power supply; and The electrostatic chuck on the base, The lifting mechanism comprises: a conductive ring capable of electrically coupling with the edge ring while supporting the edge ring mounted thereon; a rod extending in a vertical direction below the conductive ring; an actuator configured to move the edge ring up and down via the rod and the conductive ring; and A connection member that provides electrical connection between the conductive ring and the base is configured to maintain the electrical connection as the conductive ring moves.

2. The plasma processing device according to claim 1, characterized in that: The connecting member is capable of deforming as the conductive ring moves.

3. The plasma processing device according to claim 2, characterized in that: The connecting member includes a bellows, a contact belt or a cylindrical member, and a plurality of slits are formed on a side wall surface of the cylindrical member so as to enable elastic deformation in a longitudinal direction thereof.

4. The plasma processing device according to any one of claims 1 to 3, characterized in that: The rod has insulating properties.

5. The plasma processing device according to any one of claims 1 to 3, characterized in that: The region of the conductive ring exposed on the surface is covered with a film resistant to the plasma.

6. The plasma processing device according to any one of claims 1 to 3, characterized in that: The edge ring is an upper edge ring, The plasma processing device also includes a lower edge ring, the upper edge ring is arranged on the lower edge ring, The electrostatic chuck comprises: a first portion having a substrate supporting surface; and a second portion extending outside the first portion and having a ring support surface extending at a position lower than the substrate support surface, The first portion includes a sidewall surface extending between the substrate support surface and the ring support surface, The lower edge ring is disposed on the ring support surface along the side wall surface.

7. The plasma processing device according to claim 6, characterized in that: The lower edge ring comprises: an inner peripheral portion disposed along the side wall surface; An outer peripheral portion extending radially outwardly relative to the inner peripheral portion, the upper edge ring being disposed on the outer peripheral portion; and An intermediate portion extends between the inner peripheral portion and the outer peripheral portion, and the intermediate portion is located between an edge of the substrate on the substrate supporting surface and an inner peripheral surface of the upper edge ring.

8. The plasma processing device according to claim 6, characterized in that: The lower edge ring is electrically conductive.

9. The plasma processing device according to claim 6, characterized in that: The lower edge ring has insulating properties.

10. The plasma processing device according to claim 6, characterized in that: Also included is another lifting mechanism configured to lift the upper edge ring or a ring set including the upper edge ring and the lower edge ring from the electrostatic chuck.

11. The plasma processing device according to any one of claims 1 to 3, characterized in that: A switch is also included, the switch being configured to be able to switch between a first state in which the edge ring and the base are electrically coupled to each other and a second state in which the edge ring and the base are electrically separated from each other.

12. The plasma processing device according to claim 11, characterized in that: The lifting mechanism is the switch, and is configured to be able to lower the conductive ring by the actuator to separate the conductive ring from the edge ring, thereby forming the second state.

13. The plasma processing device according to claim 11, characterized in that: The switch includes a switch element connected between the connection member and the conductive ring or between the connection member and the base.

14. The plasma processing device according to claim 11, characterized in that: The switch includes another lifting mechanism configured to form the second state by lifting the edge ring from the conductive ring.

15. The plasma processing device according to claim 11, characterized in that: The system further includes a control unit configured to control the switch according to the read scheme to form the first state or the second state.

16. The plasma processing device according to claim 11, characterized in that: Also includes: a measuring device configured to measure an etching depth of the substrate on the substrate support; and The control unit is configured to control the switch to switch from the second state to the first state when the etching depth measured by the measuring device reaches a threshold value.

17. A substrate processing system, characterized in that: include: The plasma processing device according to claim 10; A conveying module, comprising a conveying chamber and a conveying robot connected to the plasma processing device; a ring storage magazine configured to receive the upper edge ring or the upper edge ring and the ring set therein; and Control Department, The control unit is configured to control the other lifting mechanism and the transport robot to replace the upper edge ring or the ring group in the chamber of the plasma processing device with the upper edge ring or the ring group in the chamber via the transport chamber.

18. A substrate processing system, characterized in that: include: The plasma processing device according to claim 11; an imaging device configured to acquire an image of the substrate after being etched by the plasma processing device; and Control Department, The control unit is configured to control the switch to form the first state when the substrate is subsequently etched in the plasma processing device when it is determined based on the image of the previously processed substrate that the roundness of the holes in the edge area of ​​the substrate is below a threshold.

19. A substrate processing system, characterized in that: include: The plasma processing device according to claim 11; a measuring device configured to measure a thickness of a deposit of the edge ring; and Control Department, The control unit is configured to control the switch during the cleaning process in the chamber so as to establish the second state when the thickness of the deposit is less than a threshold value, and to establish the first state when the thickness of the deposit is greater than or equal to the threshold value.

Images