Plasma processing apparatus

Abstract

To provide a technique to prevent reaction products from entering a gap between a substrate on a substrate support portion and an edge ring during plasma processing and adhering to the substrate support portion.SOLUTION: A plasma processing apparatus includes a chamber, a substrate support, an edge ring, a plasma generation unit, and a control unit, and the control unit is configured to perform the following controls: (a) when a first substrate is placed on the substrate support surface of the substrate support unit, generate plasma in the chamber using the plasma generation unit to form a conductive film in an area outside the first substrate on the inner upper surface and outer upper surface of the edge ring; and (b) when a second substrate having a larger diameter than the first substrate is placed on the substrate support surface and on the conductive film on the inner upper surface, generate plasma in the chamber using the plasma generation unit to plasma process the second substrate.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] SUMMARY OF THE INVENTION An exemplary embodiment of the present disclosure relates to a plasma processing apparatus. [Background technology]

[0002] Patent Documents 1 and 2 disclose techniques for pre-coating members inside a chamber. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2023-50155 [Patent Document 2] Patent Publication No. 2021-136255 Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides a technique for preventing reaction products from entering a gap between a substrate on a substrate support and an edge ring during plasma processing and adhering to the substrate support. [Means for solving the problem]

[0005] In one exemplary embodiment of the present disclosure, a plasma processing apparatus includes a chamber, a substrate support member disposed within the chamber and having a substrate support surface, an edge ring disposed to surround the substrate support surface of the substrate support member, the edge ring having an inner upper surface and an outer upper surface, the inner upper surface being lower than the substrate support surface and the outer upper surface being higher than the inner upper surface, a plasma generation member configured to generate plasma from a gas supplied into the chamber, and a control unit, wherein the control unit is configured to perform the following controls: (a) when a first substrate is disposed on the substrate support surface of the substrate support member, control the plasma generation member to generate plasma in the chamber to form a conductive film on a region on the inner upper surface and outer upper surface of the edge ring outside the first substrate; and (b) when a second substrate having a diameter larger than the first substrate is disposed on the substrate support surface and on the conductive film on the inner upper surface, control the plasma generation member to generate plasma in the chamber to plasma process the second substrate. [Effects of the Invention]

[0006] According to one exemplary embodiment of the present disclosure, a technology can be provided that prevents reaction products from entering a gap between a substrate on a substrate support and an edge ring and adhering to the substrate support during plasma processing. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram illustrating an example of the configuration of a plasma processing system. [Figure 2] FIG. 1 is a diagram illustrating an example of the configuration of a plasma processing apparatus. [Figure 3] FIG. 10 is a diagram for explaining a configuration example of an edge ring. [Figure 4] 3 is a flowchart illustrating an example of a plasma processing method according to the first embodiment. [Figure 5] FIG. 10 is a view for explaining a state in which the first substrate is placed on a substrate support surface in step ST2-1. [Figure 6] 10A and 10B are diagrams for explaining a state in which a conductive film is formed on the edge ring in step ST2-1. [Figure 7] FIG. 10 is a view for explaining a state in which a second substrate is placed on a substrate support surface in step ST3-1. [Figure 8] 10 is a flowchart illustrating an example of a plasma processing method according to a second embodiment. [Figure 9] FIG. 10 is a view for explaining a state in which a part of the first conductive film on the edge ring is removed in step ST3-2. [Figure 10] FIG. 10 is a view for explaining a state in which a third substrate is placed on a substrate support surface in step ST4-2. [Figure 11] FIG. 10 is a view for explaining a state in which a second conductive film is formed on the edge ring in step ST4-2. [Figure 12] FIG. 10 is a view for explaining a state in which a fourth substrate is placed on a substrate support surface in step ST5-2. [Figure 13] FIG. 10 is a diagram illustrating a state in which a second substrate having an inclined outer circumferential back surface is placed on a substrate support surface. DETAILED DESCRIPTION OF THE INVENTION

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

[0009] In one exemplary embodiment, there is provided a plasma processing apparatus including: a chamber; a substrate support member disposed within the chamber and having a substrate support surface; an edge ring disposed to surround the substrate support surface of the substrate support member, the edge ring having an inner upper surface and an outer upper surface, the inner upper surface being lower than the substrate support surface and the outer upper surface being higher than the inner upper surface; a plasma generating unit configured to generate plasma from a gas supplied into the chamber; and a controller, wherein the controller is configured to: (a) control the plasma generating unit to generate plasma in the chamber when a first substrate is disposed on the substrate support surface of the substrate support member, to form a conductive film on a region on the inner upper surface and the outer upper surface of the edge ring outside the first substrate; and (b) control the plasma generating unit to generate plasma in the chamber when a second substrate having a diameter larger than the first substrate is disposed on the substrate support surface and on the conductive film on the inner upper surface, to plasma process the second substrate.

[0010] In one exemplary embodiment, a plasma generating unit configured to generate plasma from a gas supplied into the chamber is included, the plasma generating unit being configured to generate plasma from a gas supplied into the chamber ... a plasma generating unit generating plasma in the chamber to remove the first conductive film in a region on the inner upper surface and the outer upper surface that is outside the second substrate and to leave the first conductive film in a region on the inner upper surface that vertically overlaps with the second substrate; (c) a third substrate having a diameter larger than the first substrate is placed on the substrate support surface and on the first conductive film on the inner upper surface, and a second conductive film is formed in a region on the inner upper surface and the outer upper surface of the edge ring that is outside the third substrate; and (d) a fourth substrate having a diameter larger than the first substrate is placed on the substrate support surface and on the first conductive film on the inner upper surface, and a plasma generating unit generating plasma in the chamber to plasma process the fourth substrate.

[0011] Hereinafter, each embodiment of the present disclosure will be described in detail with reference to the drawings. In each drawing, the same or similar elements are designated by the same reference numerals, and redundant explanations will be omitted. Unless otherwise specified, the positional relationships, such as up, down, left, and right, will be described based on the positional relationships shown in the drawings. The dimensional ratios in the drawings do not represent actual ratios, and the actual ratios are not limited to the ratios shown in the drawings.

[0012] <Configuration example of plasma processing system> FIG. 1 is a diagram illustrating an exemplary configuration of a plasma processing system. In one embodiment, the plasma processing system includes a plasma processing device 1 and a control unit 2. The plasma processing system is an example of a substrate processing system, and the plasma processing device 1 is an example of a substrate processing device. The plasma processing device 1 includes a plasma processing chamber 10, a substrate support 11, and a plasma generation unit 12. The plasma processing chamber 10 has a plasma processing space. The plasma processing chamber 10 also has at least one gas supply port for supplying at least one processing gas to the plasma processing space and at least one gas exhaust port for exhausting gas from the plasma processing space. The gas supply port is connected to a gas supply unit 20 (described later), and the gas exhaust port is connected to an exhaust system 40 (described later). The substrate support 11 is disposed in the plasma processing space and has a substrate support surface for supporting a substrate.

[0013] The plasma generating unit 12 is configured to generate plasma from at least one processing gas supplied into the plasma processing space. The plasma formed in the plasma processing space may be capacitively coupled plasma (CCP), inductively coupled plasma (ICP), electron-cyclotron-resonance plasma (ECR plasma), helicon wave plasma (HWP), or surface wave plasma (SWP). Various types of plasma generating units may be used, including alternating current (AC) plasma generating units and direct current (DC) plasma generating units. In one embodiment, the AC signal (AC power) used in the AC plasma generating unit has a frequency in the range of 100 kHz to 10 GHz. Therefore, the AC signal includes a radio frequency (RF) signal and a microwave signal. In one embodiment, the RF signal has a frequency in the range of 100 kHz to 150 MHz.

[0014] The control unit 2 processes computer-executable instructions that cause the plasma processing apparatus 1 to perform various processes described in this disclosure. The control unit 2 may be configured to control each element of the plasma processing apparatus 1 to perform various processes described herein. In one embodiment, part or all of the control unit 2 may be included in the plasma processing apparatus 1. The control unit 2 may include a processing unit 2a1, a storage unit 2a2, and a communication interface 2a3. The control unit 2 may be implemented by, for example, a computer 2a. The processing unit 2a1 may be configured to read a program from the storage unit 2a2 and execute the read program to perform various control operations. The program may be stored in the storage unit 2a2 in advance or may be acquired via a medium when needed. The acquired program is stored in the storage unit 2a2 and read from the storage unit 2a2 by the processing unit 2a1 for execution. The medium may be various storage media readable by the computer 2a or a communication line connected to the communication interface 2a3. The processing unit 2a1 may be a CPU (Central Processing Unit). The storage unit 2a2 may include a random access memory (RAM), a read only memory (ROM), a hard disk drive (HDD), a solid state drive (SSD), or a combination thereof. The communication interface 2a3 may communicate with the plasma processing apparatus 1 via a communication line such as a local area network (LAN).

[0015] The following describes a configuration example of a capacitively coupled plasma processing apparatus as an example of the plasma processing apparatus 1. Fig. 2 is a diagram for explaining a configuration example of a capacitively coupled plasma processing apparatus.

[0016] The capacitively coupled plasma processing apparatus 1 includes a plasma processing chamber 10, a gas supply 20, a power supply 30, and an exhaust system 40. The plasma processing apparatus 1 also includes a substrate support 11 and a gas inlet. The gas inlet is configured to introduce at least one process gas into the plasma processing chamber 10. The gas inlet includes a showerhead 13. The substrate support 11 is disposed within the plasma processing chamber 10. The showerhead 13 is disposed above the substrate support 11. In one embodiment, the showerhead 13 forms at least a portion of the ceiling of the plasma processing chamber 10. The plasma processing chamber 10 has a plasma processing space 10s defined by the showerhead 13, a sidewall 10a of the plasma processing chamber 10, and the substrate support 11. The plasma processing chamber 10 is grounded. The showerhead 13 and the substrate support 11 are electrically insulated from the housing of the plasma processing chamber 10.

[0017] The substrate support 11 includes a main body 111 and a ring assembly 112. The main body 111 has a central region 111a for supporting a substrate W and an annular region 111b for supporting the ring assembly 112. A wafer is an example of a substrate W. The annular region 111b of the main body 111 surrounds the central region 111a of the main body 111 in a plan view. The substrate W is disposed on the central region 111a of the main body 111, and the ring assembly 112 is disposed on the annular region 111b of the main body 111 so as to surround the substrate W on the central region 111a of the main body 111. Therefore, the central region 111a is also called a substrate support surface for supporting the substrate W, and the annular region 111b is also called a ring support surface for supporting the ring assembly 112.

[0018] In one embodiment, the main body 111 includes a base 1110 and an electrostatic chuck 1111. The base 1110 includes a conductive member. The conductive member of the base 1110 can function as a lower electrode. The electrostatic chuck 1111 is disposed on the base 1110. The electrostatic chuck 1111 includes a ceramic member 1111a and an electrostatic electrode 1111b disposed within the ceramic member 1111a. The ceramic member 1111a has a central region 111a. In one embodiment, the ceramic member 1111a also has an annular region 111b. Note that the annular region 111b may also be provided by another member surrounding the electrostatic chuck 1111, such as an annular electrostatic chuck or an annular insulating member. In this case, the ring assembly 112 may be disposed on the annular electrostatic chuck or the annular insulating member, or may be disposed on both the electrostatic chuck 1111 and the annular insulating member. Furthermore, at least one RF / DC electrode coupled to an RF power supply 31 and / or a DC power supply 32, which will be described later, may be disposed within the ceramic member 1111a. In this case, the at least one RF / DC electrode functions as a lower electrode. When a bias RF signal and / or a DC signal, which will be described later, is supplied to the at least one RF / DC electrode, the RF / DC electrode is also called a bias electrode. Note that the conductive member of the base 1110 and the at least one RF / DC electrode may function as multiple lower electrodes. Alternatively, the electrostatic electrode 1111b may function as a lower electrode. Therefore, the substrate support 11 includes at least one lower electrode.

[0019] The ring assembly 112 includes one or more annular members. In one embodiment, the one or more annular members include one or more edge rings and at least one cover ring. The edge rings are formed of a conductive or insulating material, and the cover rings are formed of an insulating material.

[0020] The substrate support 11 may also include a temperature adjustment module configured to adjust at least one of the electrostatic chuck 1111, the ring assembly 112, and the substrate to a target temperature. The temperature adjustment module may include a heater, a heat transfer medium, a flow passage 1110a, or a combination thereof. A heat transfer fluid such as brine or a gas flows through the flow passage 1110a. In one embodiment, the flow passage 1110a is formed in the base 1110, and one or more heaters are disposed in the ceramic member 1111a of the electrostatic chuck 1111. The substrate support 11 may also include a heat transfer gas supply configured to supply a heat transfer gas to a gap between the backside of the substrate W and the central region 111a.

[0021] The showerhead 13 is configured to introduce at least one processing gas from the gas supply unit 20 into the plasma processing space 10s. The showerhead 13 has at least one gas supply port 13a, at least one gas diffusion chamber 13b, and multiple gas inlets 13c. The processing gas supplied to the gas supply port 13a passes through the gas diffusion chamber 13b and is introduced into the plasma processing space 10s from the multiple gas inlets 13c. The showerhead 13 also includes at least one upper electrode. In addition to the showerhead 13, the gas introduction unit may also include one or more side gas injectors (SGIs) attached to one or more openings formed in the sidewall 10a.

[0022] The gas supply unit 20 may include at least one gas source 21 and at least one flow controller 22. In one embodiment, the gas supply unit 20 is configured to supply at least one process gas from a corresponding gas source 21 to the showerhead 13 via a corresponding flow controller 22. Each flow controller 22 may include, for example, a mass flow controller or a pressure-controlled flow controller. Additionally, the gas supply unit 20 may include at least one flow modulation device that modulates or pulses the flow rate of the at least one process gas.

[0023] The power supply 30 includes an RF power supply 31 coupled to the plasma processing chamber 10 via at least one impedance matching circuit. The RF power supply 31 is configured to supply at least one RF signal (RF power) to at least one lower electrode and / or at least one upper electrode. This generates a plasma from at least one processing gas supplied to the plasma processing space 10s. Therefore, the RF power supply 31 can function as at least a part of the plasma generation unit 12. Furthermore, by supplying a bias RF signal to the at least one lower electrode, a bias potential is generated on the substrate W, and ion components in the formed plasma can be attracted to the substrate W.

[0024] In one embodiment, the RF power supply 31 includes a first RF generating unit 31a and a second RF generating unit 31b. The first RF generating unit 31a is coupled to at least one lower electrode and / or at least one upper electrode via at least one impedance matching circuit and is configured to generate a source RF signal (source RF power) for plasma generation. In one embodiment, the source RF signal has a frequency in the range of 10 MHz to 150 MHz. In one embodiment, the first RF generating unit 31a may be configured to generate multiple source RF signals having different frequencies. The generated one or more source RF signals are supplied to at least one lower electrode and / or at least one upper electrode.

[0025] The second RF generating unit 31b is coupled to at least one lower electrode via at least one impedance matching circuit and configured to generate a bias RF signal (bias RF power). The frequency of the bias RF signal may be the same as or different from the frequency of the source RF signal. In one embodiment, the bias RF signal has a frequency lower than the frequency of the source RF signal. In one embodiment, the bias RF signal has a frequency in the range of 100 kHz to 60 MHz. In one embodiment, the second RF generating unit 31b may be configured to generate multiple bias RF signals having different frequencies. The generated one or more bias RF signals are supplied to at least one lower electrode. In various embodiments, at least one of the source RF signal and the bias RF signal may be pulsed.

[0026] The power supply 30 may also include a DC power supply 32 coupled to the plasma processing chamber 10. The DC power supply 32 includes a first DC generator 32a and a second DC generator 32b. In one embodiment, the first DC generator 32a is connected to at least one lower electrode and configured to generate a first DC signal. The generated first DC signal is applied to the at least one lower electrode. In one embodiment, the second DC generator 32b is connected to at least one upper electrode and configured to generate a second DC signal. The generated second DC signal is applied to the at least one upper electrode.

[0027] In various embodiments, the first and second DC signals may be pulsed. In this case, a sequence of voltage pulses is applied to at least one lower electrode and / or at least one upper electrode. The voltage pulses may have a rectangular, trapezoidal, triangular, or combination thereof. In one embodiment, a waveform generator for generating a sequence of voltage pulses from the DC signal is connected between the first DC generator 32a and at least one lower electrode. Thus, the first DC generator 32a and the waveform generator constitute a voltage pulse generator. When the second DC generator 32b and the waveform generator constitute a voltage pulse generator, the voltage pulse generator is connected to at least one upper electrode. The voltage pulses may have either positive or negative polarity. Furthermore, the sequence of voltage pulses may include one or more positive voltage pulses and one or more negative voltage pulses within one period. The first and second DC generating units 32a and 32b may be provided in addition to the RF power supply 31, or the first DC generating unit 32a may be provided instead of the second RF generating unit 31b.

[0028] The exhaust system 40 may be connected to, for example, a gas exhaust port 10e provided at the bottom of the plasma processing chamber 10. The exhaust system 40 may include a pressure regulating valve and a vacuum pump. The pressure regulating valve regulates the pressure in the plasma processing space 10s. The vacuum pump may include a turbomolecular pump, a dry pump, or a combination thereof.

[0029] <Edge ring configuration example> In one embodiment, the plasma processing apparatus 1 includes an edge ring 200 arranged to surround the substrate support surface 111a of the substrate support 11. The edge ring 200 is made of a conductive material. The edge ring 200 may be composed of a single member or multiple members. The edge ring 200 is included in a ring assembly 112.

[0030] In one embodiment, as shown in FIG. 3 , the edge ring 200 has an inner annular portion 210 and an outer annular portion 211. The outer annular portion 211 is located outside the inner annular portion 210. The inner annular portion 210 has an inner upper surface 220 that is lower than the substrate support surface 111a of the substrate support unit 11. The outer annular portion 211 has an outer upper surface 221 that is higher than the inner upper surface 220 of the inner annular portion 210 and the substrate support surface 111a. In one embodiment, the inner upper surface 220 of the inner annular portion 210 and the outer upper surface 221 of the outer annular portion 211 are connected by a vertical wall 222. A substrate W to be plasma processed in the plasma processing apparatus 1 (a processing substrate) has a diameter larger than the substrate support surface 111a. When the substrate W is supported on the substrate support surface 111a, the outer edge of the substrate W is located above the inner upper surface 220. This forms a gap between the substrate W on the substrate support surface 111a and the edge ring 200.

[0031] <An example of a plasma processing method> (First embodiment) FIG. 4 is a flowchart showing an example of a plasma processing method (hereinafter also referred to as "this processing method") in one example embodiment. In one embodiment, this processing method is performed in a plasma processing apparatus 1. This processing method is executed by a control unit 2 controlling each unit of the plasma processing apparatus 1. In one embodiment, this processing method includes a step ST1-1 of cleaning the inside of the chamber 10, a step ST2-1 of forming a conductive film on the edge ring 200, a step ST3-1 of plasma processing a substrate, a step ST4-1 of cleaning the inside of the chamber 10, and a determination step ST5-1.

[0032] 2 is cleaned. In this cleaning, the inner wall surface of the chamber 10 and the members disposed inside the chamber 10 may be cleaned. First, a dummy substrate is placed on a substrate support 11 inside the chamber 10 and is held by suction on the substrate support 11. The dummy substrate may have the same size as the substrate W to be processed.

[0033] Next, plasma is generated in the chamber 10 by the plasma generating unit 12. At this time, a cleaning gas is first supplied to the shower head 13 by the gas supply unit 20, and then supplied from the shower head 13 into the chamber 10. The cleaning gas contains a gas that generates activated species necessary for cleaning the inside of the chamber 10. The cleaning gas may contain a CF-based gas such as CF gas. The cleaning gas may also contain oxygen gas such as O gas or ozone gas.

[0034] A source RF signal for generating plasma is supplied to the upper electrode and / or lower electrode by RF power supply 31 of plasma generating unit 12. The atmosphere in chamber 10 is exhausted from gas exhaust port 10e, and the pressure inside chamber 10 is reduced. In this way, plasma is generated from the cleaning gas inside chamber 10, and deposits inside chamber 10 are removed by the plasma. Thereafter, plasma generation is stopped, and the dummy substrate is removed from chamber 10.

[0035] In step ST2-1, a conductive film is formed on the edge ring 200. First, as shown in FIG. 5, a first substrate W1 is placed on the substrate support member 11 in the chamber 10 and is held by suction on the substrate support surface 111a of the substrate support member 11. The first substrate W1 has a smaller diameter than the second substrate W2 used in step ST3-1. The second substrate W2 may be a process substrate (product substrate). The first substrate W1 may have a diameter approximately 1 mm to 5 mm smaller than that of the second substrate W2. The first substrate W1 may be a bare silicon substrate. The first substrate W1 may have a diameter equal to or larger than the substrate support surface 111a.

[0036] Next, plasma is generated in the plasma processing space 10s by the plasma generation unit 12. At this time, a film formation gas is first supplied to the shower head 13 by the gas supply unit 20 shown in FIG. 2 and then supplied from the shower head 13 into the chamber 10. The film formation gas contains a gas that generates activated species necessary for film formation on the edge ring 200. The film formation gas may contain a carbon-containing gas. The carbon-containing gas may be a hydrocarbon gas. The film formation gas may further contain oxygen gas.

[0037] Next, a source RF signal for generating plasma is supplied to the upper electrode and / or lower electrode by the RF power supply 31 of the plasma generation unit 12. A bias signal for attracting ion components in the plasma to the substrate may be supplied to the lower electrode by the RF power supply 31 or the DC power supply 32. The atmosphere in the chamber 10 is exhausted through the gas exhaust port 10e, and the pressure inside the chamber 10 is reduced. Thus, plasma is generated from the film-forming gas in the plasma processing space 10s of the chamber 10. As a result, as shown in FIG. 6 , a conductive film A1 is formed on the edge ring 200 by the plasma. At this time, the conductive film A1 is formed on the surface of the first substrate W1 exposed in the plasma processing space 10s and on the inner upper surface 220 and outer upper surface 221 of the edge ring 200. The conductive film A1 is formed in a ring shape in the region of the edge ring 200 outside the first substrate W1 on the inner upper surface 220 and outer upper surface 221. The conductive film A1 is formed to be equal to or higher than the substrate support surface 111a. That is, the conductive film A1 has a thickness D1 equal to or greater than the height difference ΔL1 between the substrate support surface 111a and the inner upper surface 220. The conductive film A1 may be a carbon-containing film. The conductive film A1 may have higher elasticity and softness than the processing substrate W. When a predetermined conductive film A1 is formed, plasma generation is stopped, and the first substrate W1 is removed from the chamber 10.

[0038] In step ST3-1, a second substrate W2 is plasma-processed. The plasma processing may be an etching process for etching a film on the substrate. First, as shown in FIG. 7, the second substrate W2 is placed on the substrate support member 11 in the chamber 10 and held by suction on the substrate support surface 111a of the substrate support member 11. The second substrate W2 is a processing substrate that will become a product and may be used in the manufacture of semiconductor devices. Examples of semiconductor devices include memory devices such as DRAMs and 3D-NAND flash memories, and logic devices. The second substrate W2 has a larger diameter than the first substrate W1. As a result of being held by suction on the substrate support surface 111a, the second substrate W2 is also placed on the conductive film A1 on the inner upper surface 220 of the edge ring 200. At this time, the conductive film A1 may be crushed by the rear surface of the second substrate W2. The conductive film A1 is in close contact with the rear surface of the second substrate W2.

[0039] Next, plasma is generated in the plasma processing space 10s by the plasma generation unit 12. At this time, a processing gas is first supplied to the shower head 13 by the gas supply unit 20 shown in Fig. 2, and then supplied from the shower head 13 to the plasma processing space 10s. The processing gas contains a gas that generates activated species necessary for etching the second substrate W2.

[0040] Next, a source RF signal for generating plasma is supplied to the upper electrode and / or lower electrode by the RF power supply 31 of the plasma generation unit 12. A bias signal for attracting ion components in the plasma to the second substrate W2 may be supplied to the lower electrode by the RF power supply 31 or DC power supply 32. The atmosphere in the plasma processing space 10s is exhausted through the gas exhaust port 10e, and the inside of the plasma processing space 10s is depressurized. Thus, plasma is generated from the processing gas on the substrate support 11 in the plasma processing space 10s, and the second substrate W2 is etched. Thereafter, the plasma generation is stopped, and the second substrate W2 is unloaded from the chamber 10.

[0041] In step ST4-1, the inside of the chamber 10 is cleaned without a substrate being placed on the substrate support member 11 (substrate-less dry cleaning).

[0042] First, plasma is generated in the chamber 10 by the plasma generating unit 12. At this time, a cleaning gas is supplied to the shower head 13 by the gas supply unit 20 and then supplied from the shower head 13 into the chamber 10. The cleaning gas contains a gas that generates activated species necessary for cleaning the inside of the chamber 10. The cleaning gas may contain a CF-based gas such as CF gas, and an oxygen gas such as O gas or ozone gas.

[0043] A source RF signal for generating plasma is supplied to the upper electrode and / or lower electrode by the RF power supply 31 of the plasma generating unit 12. The atmosphere in the chamber 10 is exhausted from the gas exhaust port 10e, and the pressure inside the chamber 10 is reduced. In this way, plasma is generated from the cleaning gas inside the chamber 10, and deposits inside the chamber 10 are removed by the plasma. Thereafter, the generation of plasma is stopped.

[0044] Thereafter, in one embodiment, if the processing of the set number of substrates has been completed, the present processing method ends, and if the processing of the set number of substrates has not been completed, the processing returns to step ST1-1 of the present processing method (determination step ST5-1). When steps ST1-1 to ST4-1 of the present processing method are repeatedly performed on multiple substrates, a thick conductive film A1 may be formed in the first step ST2-1, and in subsequent steps ST2-1, the conductive film A1 may be formed in a film formation amount smaller than the film formation amount in the first step. In subsequent steps ST2-1, the conductive film A1 may be formed in an amount that corresponds to the amount reduced in step ST4-1.

[0045] According to this exemplary embodiment, the control unit 2 of the plasma processing apparatus 1 is configured to execute the following controls: (a) with the first substrate W1 disposed on the substrate support surface 111a of the substrate support member 11, generate plasma in the chamber 10 using the plasma generation unit 12 to form a conductive film A1 on the inner upper surface 220 and the outer upper surface 221 of the edge ring 200 in a region outside the first substrate W1; and (b) with the second substrate W2 having a larger diameter than the first substrate W1 disposed on the substrate support surface 111a and the conductive film A1 on the inner upper surface 220, generate plasma in the chamber 10 using the plasma generation unit 12 to plasma process the second substrate W2. In this case, since the substrate is disposed on the substrate support surface 111a and the conductive film A1 on the inner upper surface 220 during plasma processing, reaction products generated during plasma processing are prevented from entering the gap between the inner upper surface 220 and the substrate and adhering to the substrate support member 11.

[0046] Furthermore, during plasma processing, the conductive film A1 electrically connects the substrate to the edge ring 200. This equalizes the potentials of the substrate and the edge ring 200, reducing the difference in the thickness of the plasma sheath between the substrate and the edge ring 200. As a result, fluctuations in the tilt angle (the angle of ion entry) at the outer periphery of the substrate are reduced, resulting in uniform plasma processing within the substrate surface.

[0047] Furthermore, since the substrate and the edge ring 200 are connected by the conductive film A1, the temperature difference between the substrate and the edge ring 200 is reduced. As a result, the processing of the outer periphery of the substrate can be prevented from being affected by the temperature difference between the substrate and the edge ring 200.

[0048] (Second embodiment) 8 is a flowchart showing an example of a plasma processing method according to an illustrative embodiment. This processing method is performed by the control unit 2 controlling each unit of the plasma processing apparatus 1. In one embodiment, this processing method includes a step ST1-2 of cleaning the inside of the chamber 10, a step ST2-2 of forming a first conductive film on the edge ring 200, a step ST3-2 of removing a portion of the first conductive film, a step ST4-2 of forming a second conductive film on the edge ring 200, a step ST5-2 of plasma processing the substrate, a step ST6-2 of cleaning the inside of the chamber 10, and a determination step ST7-2.

[0049] 2 is cleaned. In this cleaning, the inner wall surface of the chamber 10 and the members disposed inside the chamber 10 may be cleaned. First, a dummy substrate is placed on the substrate support portion 11 inside the chamber 10 and is held by suction on the substrate support portion 11. The dummy substrate may have the same size as the substrate W to be processed.

[0050] Next, plasma is generated in the chamber 10 by the plasma generating unit 12. At this time, a cleaning gas is first supplied to the shower head 13 by the gas supply unit 20, and then supplied from the shower head 13 into the chamber 10. The cleaning gas contains a gas that generates activated species necessary for cleaning the inside of the chamber 10. The cleaning gas may contain a CF-based gas such as CF gas. The cleaning gas may also contain oxygen gas such as O gas or ozone gas.

[0051] A source RF signal for generating plasma is supplied to the upper electrode and / or lower electrode by RF power supply 31 of plasma generating unit 12. The atmosphere in chamber 10 is exhausted from gas exhaust port 10e, and the pressure inside chamber 10 is reduced. In this way, plasma is generated from the cleaning gas inside chamber 10, and deposits inside chamber 10 are removed by the plasma. Thereafter, plasma generation is stopped, and the dummy substrate is removed from chamber 10.

[0052] In step ST2-2, a first conductive film is formed on the edge ring 200. First, as shown in FIG. 5, a first substrate W1 is placed on the substrate support member 11 in the chamber 10 and is held by suction on the substrate support surface 111a of the substrate support member 11. The first substrate W1 has a smaller diameter than the fourth substrate W4 used in step ST4-2. Here, the fourth substrate W4 may be a process substrate (product substrate). The first substrate W1 may have a diameter approximately 1 mm to 5 mm smaller than that of the fourth substrate W4. The first substrate W1 may be a bare silicon substrate. The first substrate W1 may have a diameter equal to or larger than the substrate support surface 111a.

[0053] Next, plasma is generated in the plasma processing space 10s by the plasma generation unit 12. At this time, a first film formation gas is first supplied to the shower head 13 by the gas supply unit 20 shown in FIG. 2 and then supplied from the shower head 13 into the chamber 10. The first film formation gas contains a gas that generates activated species necessary for film formation on the edge ring 200. The first film formation gas may contain a carbon-containing gas. The carbon-containing gas may be a hydrocarbon gas. The first film formation gas may further contain oxygen gas.

[0054] Next, a source RF signal for generating plasma is supplied to the upper electrode and / or lower electrode by the RF power supply 31 of the plasma generation unit 12. A bias signal for attracting ion components in the plasma to the substrate may be supplied to the lower electrode by the RF power supply 31 or the DC power supply 32. The atmosphere in the chamber 10 is exhausted through the gas exhaust port 10e, and the pressure inside the chamber 10 is reduced. Thus, plasma is generated from the first film formation gas in the plasma processing space 10s of the chamber 10. As a result, as shown in FIG. 6 , a first conductive film A1 is formed on the edge ring 200 by the plasma. At this time, the first conductive film A1 is formed on the surface of the first substrate W1 exposed in the plasma processing space 10s and on the inner upper surface 220 and outer upper surface 221 of the edge ring 200. The first conductive film A1 is formed in a ring shape in the region of the edge ring 200 outside the first substrate W1 on the inner upper surface 220 and outer upper surface 221. The first conductive film A1 is formed to be equal to or higher than the substrate support surface 111a. That is, the first conductive film A1 has a thickness D1 equal to or greater than the height difference ΔL1 between the substrate support surface 111a and the inner upper surface 220. The first conductive film A1 may be a carbon-containing film. The first conductive film A1 may have higher elasticity and softness than the processing substrate. When a given first conductive film A1 is formed, plasma generation is stopped, and the first substrate W1 is removed from the chamber 10.

[0055] In step ST3-2, a portion of the first conductive film A1 on the edge ring 200 is removed. First, as shown in FIG. 7, a second substrate W2 is placed on the substrate support member 11 in the chamber 10 and is suction-held on the substrate support surface 111a of the substrate support member 11. The second substrate W2 has a larger diameter than the first substrate W1. The second substrate W2 may have the same diameter as the processing substrate (product substrate). As a result of being suction-held on the substrate support surface 111a, the second substrate W2 is also placed on the first conductive film A1 on the inner upper surface 220 of the edge ring 200. Therefore, a portion of the first conductive film A1 is covered by the second substrate W2.

[0056] Next, plasma is generated in the plasma processing space 10s by the plasma generation unit 12. At this time, an etching gas is first supplied to the shower head 13 by the gas supply unit 20 shown in FIG. 2 and then supplied from the shower head 13 into the chamber 10. The etching gas contains a gas that generates activated species necessary for removing the first conductive film A1 on the edge ring 200. The etching gas may contain a fluorine-containing gas. The etching gas may contain a CF-based gas such as CF gas. The etching gas may also contain oxygen gas such as O gas or ozone gas.

[0057] Next, a source RF signal for generating plasma is supplied to the upper electrode and / or lower electrode by the RF power supply 31 of the plasma generating unit 12. A bias signal for attracting ion components in the plasma to the substrate may be supplied to the lower electrode by the RF power supply 31 or the DC power supply 32. The atmosphere in the chamber 10 is exhausted through the gas exhaust port 10e, and the pressure inside the chamber 10 is reduced. Thus, plasma is generated from the etching gas in the plasma processing space 10s of the chamber 10. As a result, as shown in FIG. 9 , a portion of the first conductive film A1 on the edge ring 200 is removed by the plasma. At this time, the portion of the first conductive film A1 that is not covered by the second substrate W2 and is exposed to the plasma processing space 10s is removed. That is, the first conductive film A1 in the regions outside the second substrate W2 on the inner upper surface 220 and the outer upper surface 221 of the edge ring 200 is removed. The first conductive film A1 below the second substrate W2 remains. The first conductive film A1 in the inner region of the inner upper surface 220 remains, and the first conductive film A1 in the outer region of the inner upper surface 220 and the first conductive film A1 on the outer upper surface 221 are removed. Thereafter, the plasma generation is stopped, and the second substrate W2 is unloaded from the chamber 10.

[0058] In step ST4-2, a second conductive film is formed on the edge ring 200. First, as shown in FIG. 10, a third substrate W3 is placed on the substrate support member 11 in the chamber 10 and is suction-held on the substrate support surface 111a of the substrate support member 11. The third substrate W3 has a larger diameter than the first substrate W1. The third substrate W3 may have the same diameter as the second substrate W2. The third substrate W3 may have the same diameter as the processing substrate (product substrate). As a result of being suction-held on the substrate support surface 111a, the third substrate W3 is also placed on the first conductive film A1 on the inner upper surface 220 of the edge ring 200. Therefore, the first conductive film A1 is covered by the third substrate W3.

[0059] Next, plasma is generated in the plasma processing space 10s by the plasma generation unit 12. At this time, first, a second film formation gas is supplied to the shower head 13 by the gas supply unit 20 shown in FIG. 2 and then supplied from the shower head 13 into the chamber 10. The second film formation gas contains a gas that generates activated species necessary for film formation on the edge ring 200. The second film formation gas may contain a carbon-containing gas. The carbon-containing gas may be a hydrocarbon gas. The second film formation gas may further contain oxygen gas. The second film formation gas may be a gas different from the first film formation gas.

[0060] Next, a source RF signal for generating plasma is supplied to the upper electrode and / or lower electrode by the RF power supply 31 of the plasma generation unit 12. A bias signal for attracting ion components in the plasma to the substrate may be supplied to the lower electrode by the RF power supply 31 or the DC power supply 32. The atmosphere in the chamber 10 is exhausted through the gas exhaust port 10e, and the pressure inside the chamber 10 is reduced. Thus, plasma is generated from the second film formation gas in the plasma processing space 10s of the chamber 10. As a result, as shown in FIG. 11 , a second conductive film A2 is formed on the edge ring 200 by the plasma. At this time, the second conductive film A2 is formed on the surface of the third substrate W3 exposed in the plasma processing space 10s and on the inner upper surface 220 and outer upper surface 221 of the edge ring 200. The second conductive film A2 is formed in a ring shape in the region of the edge ring 200 outside the third substrate W3 on the inner upper surface 220 and outer upper surface 221. The second conductive film A2 is formed to have the same or lower conductivity than the first conductive film A1. The second conductive film A2 may be a carbon-containing film. The second conductive film A2 may be a film having the same composition and physical properties as the first conductive film A1. The second conductive film A2 may be a film having a different composition and physical properties from the first conductive film A1. When a given second conductive film A2 is formed, plasma generation is stopped, and the third substrate W3 is unloaded from the chamber 10.

[0061] In step ST5-2, a fourth substrate W4 is plasma-processed. The plasma processing may be an etching process for etching a film on the substrate. First, as shown in FIG. 12, the fourth substrate W4 is placed on the substrate support member 11 in the chamber 10 and held by suction on the substrate support surface 111a of the substrate support member 11. The fourth substrate W4 is a processing substrate that will become a product and may be used in the manufacture of semiconductor devices. Semiconductor devices include, for example, memory devices such as DRAMs and 3D-NAND flash memories, and logic devices. The fourth substrate W4 has a diameter larger than that of the first substrate W1. The fourth substrate W4 may have a diameter equal to that of the second substrate W2 and the third substrate W3. As a result of being held by suction on the substrate support surface 111a, the fourth substrate W4 is also placed on the first conductive film A1 on the inner upper surface 220 of the edge ring 200. At this time, the first conductive film A1 may be crushed by the rear surface of the fourth substrate W4. The first conductive film A1 is in close contact with the rear surface of the fourth substrate W4. The second conductive film A2 is exposed to the plasma processing space 10s.

[0062] Next, plasma is generated in the plasma processing space 10s by the plasma generation unit 12. At this time, a processing gas is first supplied to the shower head 13 by the gas supply unit 20 shown in Fig. 2, and then supplied from the shower head 13 to the plasma processing space 10s. The processing gas contains a gas that generates active species necessary for etching the fourth substrate W4.

[0063] Next, a source RF signal for generating plasma is supplied to the upper electrode and / or lower electrode by the RF power supply 31 of the plasma generation unit 12. A bias signal for attracting ion components in the plasma to the fourth substrate W4 may be supplied to the lower electrode by the RF power supply 31 or DC power supply 32. The atmosphere in the plasma processing space 10s is exhausted through the gas exhaust port 10e, and the pressure inside the plasma processing space 10s is reduced. Thus, plasma is generated from the processing gas on the substrate support 11 in the plasma processing space 10s, and the fourth substrate W4 is etched. Thereafter, plasma generation is stopped, and the fourth substrate W4 is unloaded from the chamber 10.

[0064] In step ST6-2, the inside of the chamber 10 is cleaned without a substrate being placed on the substrate support member 11 (substrate-less dry cleaning).

[0065] First, plasma is generated in the chamber 10 by the plasma generating unit 12. At this time, a cleaning gas is supplied to the shower head 13 by the gas supply unit 20 and then supplied from the shower head 13 into the chamber 10. The cleaning gas contains a gas that generates activated species necessary for cleaning the inside of the chamber 10. The cleaning gas may contain a CF-based gas such as CF gas, and an oxygen gas such as O gas or ozone gas.

[0066] A source RF signal for generating plasma is supplied to the upper electrode and / or lower electrode by the RF power supply 31 of the plasma generating unit 12. The atmosphere in the chamber 10 is exhausted from the gas exhaust port 10e, and the pressure inside the chamber 10 is reduced. In this way, plasma is generated from the cleaning gas inside the chamber 10, and deposits inside the chamber 10 are removed by the plasma. Thereafter, the generation of plasma is stopped.

[0067] Thereafter, in one embodiment, if the processing of the set number of substrates has been completed, the present processing method ends; if the processing of the set number of substrates has not been completed, the process returns to step ST1-2 of the present processing method (determination step ST7-2). When steps ST1-2 to ST6-2 of the present processing method are repeatedly performed on multiple substrates, the first conductive film A1 may be formed thick in the first step ST2-2, and the first conductive film A1 may be formed in a film formation amount smaller than the film formation amount in the first step in subsequent steps ST2-2. In subsequent steps ST2-2, the first conductive film A1 may be formed in an amount corresponding to the reduction in step ST6-2.

[0068] According to this exemplary embodiment, the control unit 2 of the plasma processing apparatus 1 performs the following control operations: (a) in a state in which a first substrate W1 is placed on the substrate support surface 111a of the substrate support unit 11, the control unit 2 generates plasma in the chamber 10 using the plasma generation unit 12, and controls the plasma generation unit 12 to form a first conductive film A1 in regions on the inner upper surface 220 and the outer upper surface 221 of the edge ring 200 that are outside the first substrate W1; and (b) in a state in which a second substrate W2 having a diameter larger than the first substrate W1 is placed on the substrate support surface 111a and on the first conductive film A1 on the inner upper surface 220, the control unit 2 generates plasma in the chamber 10 using the plasma generation unit 12, and controls the plasma generation unit 12 to remove the first conductive film A1 in regions on the inner upper surface 220 and the outer upper surface 221 that are outside the second substrate W2, and controls the plasma generation unit 12 to form a first conductive film A1 on the inner upper surface 220. (c) a third substrate W3 having a larger diameter than the first substrate W1 is placed on the substrate support surface 111a and on the first conductive film A1 on the inner upper surface 220, and a second conductive film A2 is formed in an area outside the third substrate W3 on the inner upper surface 220 and outer upper surface 221 of the edge ring 200; and (d) a fourth substrate W4 having a larger diameter than the first substrate W1 is placed on the substrate support surface 111a and on the first conductive film A1 on the inner upper surface 220, and a plasma is generated in the chamber 10 by the plasma generation unit 12, and the fourth substrate W4 is plasma-processed. In this case, the substrate is placed on the substrate support surface 111a and on the first conductive film A1 on the inner upper surface 220 during plasma processing, so that reaction products generated during plasma processing are prevented from entering the gap between the inner upper surface 220 and the substrate and adhering to the substrate support part 11.

[0069] Furthermore, during plasma processing, the first conductive film A1 electrically connects the substrate and the edge ring 200. This equalizes the potentials of the substrate and the edge ring 200, reducing the difference in the thickness of the plasma sheath between the substrate and the edge ring 200. As a result, fluctuations in the tilt angle (the angle of ion entry) at the outer periphery of the substrate are reduced, resulting in uniform plasma processing within the substrate surface.

[0070] Furthermore, since the substrate and the edge ring 200 are connected by the first conductive film A1, the temperature difference between the substrate and the edge ring 200 is reduced. As a result, the processing of the outer periphery of the substrate can be prevented from being affected by the temperature difference between the substrate and the edge ring 200.

[0071] The second conductive film A2 can protect the surface of the edge ring 200. Furthermore, since the first conductive film A1, which fills the gap between the substrate and the edge ring 200, and the second conductive film A2, which protects the surface of the edge ring 200, are formed separately, conductive films suited to their respective purposes can be formed.

[0072] In this embodiment, as shown in FIG. 13, the back surface WR of the second substrate W2 may have an outer back surface WR1 located higher than other portions. The outer back surface WR1 may be an inclined surface inclined with respect to the front surface WS, or may be a horizontal surface parallel to the front surface WS. This allows the first conductive film A1 to be formed in step ST2-2, and when the second substrate W2 is placed on the substrate support surface 111a in step ST3-2, the outer back surface WR1 is located on the first conductive film A1. This allows the first conductive film A1 to be formed thick, thereby improving adhesion between the fourth substrate W4 and the first conductive film A1 in the plasma processing in step ST5-2.

[0073] Although the above exemplary embodiment has been applied to a capacitively coupled plasma processing apparatus, the present invention is not limited to this and may be applied to other plasma processing apparatuses. For example, the present invention may be applied to an inductively coupled plasma processing apparatus instead of a capacitively coupled plasma processing apparatus.

[0074] Embodiments of the present disclosure further include the following aspects.

[0075] (Appendix 1) a chamber; a substrate support disposed within the chamber and having a substrate support surface; an edge ring disposed to surround the substrate support surface of the substrate support portion, the edge ring having an inner upper surface and an outer upper surface, the inner upper surface being lower than the substrate support surface and the outer upper surface being higher than the inner upper surface; a plasma generating unit configured to generate plasma from a gas supplied into the chamber; a control unit, The control unit (a) generating plasma in the chamber by the plasma generating unit while a first substrate is placed on the substrate support surface of the substrate support unit, and forming a conductive film on the inner upper surface and the outer upper surface of the edge ring in a region outside the first substrate; (b) generating plasma in the chamber by the plasma generating unit, and performing plasma processing on the second substrate, while a second substrate having a diameter larger than that of the first substrate is placed on the substrate support surface and on the conductive film on the inner upper surface. Plasma processing equipment.

[0076] (Appendix 2) a chamber; a substrate support disposed within the chamber and having a substrate support surface; an edge ring disposed to surround the substrate support surface of the substrate support portion, the edge ring having an inner upper surface and an outer upper surface, the inner upper surface being lower than the substrate support surface and the outer upper surface being higher than the inner upper surface; a plasma generating unit configured to generate plasma from a gas supplied into the chamber; a control unit, The control unit (a) generating plasma in the chamber by the plasma generating unit while a first substrate is placed on the substrate support surface of the substrate support unit, and forming a first conductive film on the inner upper surface and the outer upper surface of the edge ring in a region outside the first substrate; (b) generating plasma in the chamber by the plasma generating unit while a second substrate having a diameter larger than that of the first substrate is placed on the substrate support surface and on the first conductive film on the inner upper surface, thereby removing the first conductive film on the inner upper surface and the outer upper surface in a region outside the second substrate, and leaving the first conductive film on the inner upper surface in a region that vertically overlaps with the second substrate; (c) generating plasma in the chamber by the plasma generating unit while a third substrate having a diameter larger than that of the first substrate is placed on the substrate support surface and on the first conductive film on the inner upper surface, and forming a second conductive film on the inner upper surface and the outer upper surface of the edge ring in a region outside the third substrate; (d) generating plasma in the chamber by the plasma generating unit, and performing plasma processing on the fourth substrate, with the fourth substrate having a diameter larger than that of the first substrate, being placed on the substrate support surface and on the first conductive film on the inner upper surface. Plasma processing equipment.

[0077] The above embodiments are described for the purpose of explanation and are not intended to limit the scope of the present disclosure. Various modifications can be made to the above embodiments without departing from the scope and spirit of the present disclosure. For example, some components in one embodiment can be added to other embodiments. Also, some components in one embodiment can be replaced with corresponding components in other embodiments. [Explanation of symbols]

[0078] 1: Plasma processing apparatus, 2: Control unit, 10: Chamber, 10s: Plasma processing space, 11: Substrate support unit, 12: Plasma generation unit, 111a: Substrate support surface, 200: Edge ring, 220: Inner upper surface, 221: Outer upper surface, W1: First substrate, W2: Second substrate, W3: Third substrate, W4: Fourth substrate, A1: Conductive film, First conductive film, A2: Second conductive film

Claims

1. a chamber; a substrate support disposed within the chamber and having a substrate support surface; an edge ring disposed to surround the substrate support surface of the substrate support portion, the edge ring having an inner upper surface and an outer upper surface, the inner upper surface being lower than the substrate support surface and the outer upper surface being higher than the inner upper surface; a plasma generating unit configured to generate plasma from a gas supplied into the chamber; a control unit, The control unit (a) generating plasma in the chamber by the plasma generating unit while a first substrate is placed on the substrate support surface of the substrate support unit, and forming a conductive film on the inner upper surface and the outer upper surface of the edge ring in a region outside the first substrate; (b) generating plasma in the chamber by the plasma generating unit, and performing plasma processing on the second substrate, while a second substrate having a diameter larger than that of the first substrate is placed on the substrate support surface and on the conductive film on the inner upper surface. Plasma processing equipment.

2. a chamber; a substrate support disposed within the chamber and having a substrate support surface; an edge ring disposed to surround the substrate support surface of the substrate support portion, the edge ring having an inner upper surface and an outer upper surface, the inner upper surface being lower than the substrate support surface and the outer upper surface being higher than the inner upper surface; a plasma generating unit configured to generate plasma from a gas supplied into the chamber; a control unit, The control unit (a) generating plasma in the chamber by the plasma generating unit while a first substrate is placed on the substrate support surface of the substrate support unit, and forming a first conductive film on the inner upper surface and the outer upper surface of the edge ring in a region outside the first substrate; (b) generating plasma in the chamber by the plasma generating unit while a second substrate having a diameter larger than that of the first substrate is placed on the substrate support surface and on the first conductive film on the inner upper surface, thereby removing the first conductive film on the inner upper surface and the outer upper surface in regions outside the second substrate, and leaving the first conductive film on the inner upper surface in a region that vertically overlaps with the second substrate; (c) generating plasma in the chamber by the plasma generating unit while a third substrate having a diameter larger than the first substrate is placed on the substrate support surface and on the first conductive film on the inner upper surface, and forming a second conductive film on the inner upper surface and the outer upper surface of the edge ring in a region outside the third substrate; (d) generating plasma in the chamber by the plasma generating unit, and performing plasma processing on the fourth substrate, the fourth substrate having a diameter larger than that of the first substrate, in a state in which the fourth substrate is placed on the substrate support surface and on the first conductive film on the inner upper surface. Plasma processing equipment.

Images