Plasma processing device

Abstract

Provided is a plasma processing device which has a feature of adjusting the potential of the top part. The plasma processing device comprises: a plasma processing chamber; a substrate support part disposed in the plasma processing chamber; an upper electrode disposed above the substrate support part; a conductive annular member disposed in a manner of surrounding the upper electrode; an RF power supply electrically connected to the upper electrode; and a switching circuit electrically connected to the annular member. The switching circuit is configured to select a first state during a plasma process on a substrate on the substrate support part and to select a second state during a cleaning process in the chamber. In the first state, the annular member is electrically floating. In the second state, the annular member is electrically connected to the ground potential.

Description

Plasma processing equipment

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

[0002] Japanese Patent Application Laid-Open Nos. 2003-129999 and 2003-129999 disclose connecting a DC power supply to an upper electrode of a plasma processing apparatus.

[0003] JP 2006-270019 A JP 2015-5755 A

[0004] The present disclosure provides a technique for adjusting the potential of the ceiling of a plasma processing apparatus.

[0005] In one exemplary embodiment of the present disclosure, there is provided a plasma processing apparatus comprising: a plasma processing chamber; a substrate support disposed within the plasma processing chamber; an upper electrode disposed above the substrate support; a conductive annular member disposed to surround the upper electrode; an RF power source electrically connected to the upper electrode; and a switching circuit electrically connected to the annular member, the switching circuit configured to select a first state during plasma processing of a substrate on the substrate support and a second state during a cleaning process in the chamber, wherein in the first state the annular member is electrically floating and in the second state the annular member is electrically connected to ground potential.

[0006] According to one exemplary embodiment of the present disclosure, a technique for adjusting the potential of the ceiling of a plasma processing apparatus can be provided.

[0007] FIG. 1 is a diagram for explaining an example of the configuration of a plasma processing system. FIG. 2 is a diagram for explaining an example of the configuration of a capacitively coupled plasma processing apparatus. FIG. 3 is a diagram for explaining an example of coupling between a power supply and a chamber. FIG. 4 is a diagram for explaining an example of the configuration of a ceiling of a plasma processing apparatus. FIG. 5 is a diagram for explaining an example of connection between an annular member and a switching circuit. FIG. 6 is a diagram for explaining a first example of the configuration of a switching circuit. FIG. 7 is a diagram for explaining a first example of the configuration of a switching circuit. FIG. 8 is a diagram for explaining a second example of the configuration of a switching circuit. FIG. 9 is a diagram for explaining a configuration example of an impedance adjustment circuit. FIG. 10 is a diagram for explaining a third example of the configuration of a switching circuit.

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

[0009] In one exemplary embodiment, a plasma processing apparatus is provided, comprising: a plasma processing chamber; a substrate support disposed within the plasma processing chamber; an upper electrode disposed above the substrate support; a conductive annular member disposed surrounding the upper electrode; an RF power source electrically connected to the upper electrode; and a switching circuit electrically connected to the annular member, the switching circuit configured to select a first state during plasma processing of a substrate on the substrate support and a second state during a cleaning process in the chamber, wherein in the first state the annular member is electrically floating and in the second state the annular member is electrically connected to ground potential.

[0010] In one exemplary embodiment, the annular member is insulated from the upper electrode.

[0011] In one exemplary embodiment, the annular member is exposed to a plasma processing volume within a plasma processing chamber.

[0012] In one exemplary embodiment, the annular member is formed from silicon.

[0013] In one exemplary embodiment, the substrate support further comprises a lower electrode disposed within the substrate support and a bias generation unit electrically connected to the lower electrode, wherein the RF power supply is configured to generate an RF signal having an RF frequency of 60 MHz or greater during the cleaning process, and the bias generation unit is configured to generate at least one bias signal having a bias frequency of 13 MHz or less.

[0014] In one exemplary embodiment, the at least one bias signal includes a bias RF signal and / or a voltage pulse signal.

[0015] In one exemplary embodiment, the at least one bias signal includes a sequence of voltage pulses having a frequency in the range of 100 kHz to 1 MHz.

[0016] In one exemplary embodiment, the device further comprises a plurality of connection pins, and the switching circuit is connected to the annular member via the plurality of connection pins.

[0017] In one exemplary embodiment, the plurality of contact pins are equally spaced circumferentially along the annular member.

[0018] In one exemplary embodiment, the plurality of connection pins comprises between 4 and 12 connection pins.

[0019] In one exemplary embodiment, the device further comprises a conductive connecting ring, the connecting ring being electrically connected between the plurality of connecting pins and the switching circuit.

[0020] In one exemplary embodiment, a plasma processing apparatus is provided, comprising: a plasma processing chamber; a substrate support disposed within the plasma processing chamber; an upper electrode disposed above the substrate support; a conductive annular member disposed to surround the upper electrode; an RF power source electrically connected to the upper electrode; and a switching circuit electrically connected to the annular member, the switching circuit configured to select a first state, a second state, or a third state, wherein in the first state, the annular member is electrically floating; in the second state, the annular member is electrically connected to ground potential; and in the third state, the annular member is electrically connected to ground potential via an impedance adjustment circuit.

[0021] In one exemplary embodiment, the annular member is insulated from the upper electrode.

[0022] In one exemplary embodiment, the annular member is exposed to a plasma processing volume within a plasma processing chamber.

[0023] In one exemplary embodiment, the annular member is formed from silicon.

[0024] In one exemplary embodiment, the device further comprises a plurality of connection pins, and the switching circuit is connected to the annular member via the plurality of connection pins.

[0025] In one exemplary embodiment, the plurality of contact pins are equally spaced circumferentially along the annular member.

[0026] In one exemplary embodiment, the plurality of connection pins comprises between 4 and 12 connection pins.

[0027] In one exemplary embodiment, the device further comprises a conductive connecting ring, the connecting ring being electrically connected between the plurality of connecting pins and the switching circuit.

[0028] In one exemplary embodiment, the device further comprises a DC power supply, and the switching circuit is configured to select a first state, a second state, a third state, or a fourth state, wherein in the fourth state, the annular member is electrically connected to the DC power supply.

[0029] 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.

[0030] <Configuration Example of Plasma Processing System> FIG. 1 is a diagram illustrating a configuration 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 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.

[0031] The plasma generating unit 12 is configured to generate plasma from at least one processing gas supplied into the plasma processing space. The plasma generated in the plasma processing space may be capacitively coupled plasma (CCP), inductively coupled plasma (ICP), electron-cyclotron-resonance plasma (ECR plasma), helicon wave plasma (HWP), surface wave plasma (SWP), or the like. Various types of plasma generators may be used, including alternating current (AC) plasma generators and direct current (DC) plasma generators. In one embodiment, the AC signal (AC power) used in the AC plasma generator has a frequency in the range of 100 kHz to 10 GHz. Thus, AC signals include radio frequency (RF) signals and microwave signals. In one embodiment, the RF signal has a frequency in the range of 100 kHz to 150 MHz.

[0032] 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. This 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).

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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. Furthermore, the electrostatic electrode 1111b may function as a lower electrode. Therefore, the substrate support 11 includes at least one lower electrode.

[0037] 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.

[0038] 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.

[0039] The showerhead 13 is configured to introduce at least one process gas from the gas supply unit 20 into the plasma processing space 10s. The showerhead 13 has at least one gas supply port 13a, at least one gas diffusion chamber 13b, and multiple gas inlets 13c. The process gas supplied to the gas supply port 13a passes through the gas diffusion chamber 13b and is introduced into the plasma processing space 10s from the multiple gas inlets 13c. The showerhead 13 also includes at least one upper electrode. In addition to the showerhead 13, the gas inlet may also include one or more side gas injectors (SGIs) attached to one or more openings formed in the sidewall 10a.

[0040] 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.

[0041] 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, thereby attracting ion components in the formed plasma to the substrate W.

[0042] 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.

[0043] The second RF generator 31b is coupled to at least one lower electrode via at least one impedance matching circuit and is configured to generate a bias RF signal (bias RF power). The frequency of the bias RF signal may be the same as or different from the frequency of the source RF signal. In one embodiment, the bias RF signal has a frequency lower than the frequency of the source RF signal. In one embodiment, the bias RF signal has a frequency in the range of 100 kHz to 60 MHz. In one embodiment, the second RF generator 31b may be configured to generate multiple bias RF signals having different frequencies. The generated one or more bias RF signals are supplied to at least one lower electrode. In various embodiments, at least one of the source RF signal and the bias RF signal may be pulsed.

[0044] 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 the 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 the 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.

[0045] 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 pulse waveform. In one embodiment, a waveform generator for generating the 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.

[0046] The exhaust system 40 may be connected to, for example, a gas exhaust port 10e provided at the bottom of the plasma processing chamber 10. The exhaust system 40 may include a pressure regulating valve and a vacuum pump. The pressure in the plasma processing space 10s is regulated by the pressure regulating valve. The vacuum pump may include a turbomolecular pump, a dry pump, or a combination thereof.

[0047] <Example of Coupling Between Power Supply 30 and Chamber 10 of Plasma Processing Apparatus 1> FIG. 3 is a diagram showing an example of coupling between power supply 30 and plasma processing chamber 10 (hereinafter also referred to as "chamber 10") of plasma processing apparatus 1. As shown in FIG.

[0048] 3, in one embodiment, the first RF generator 31a is electrically connected to the upper electrode of the showerhead 13 via a transmission line L1. The transmission line L1 is provided with at least one impedance matching circuit. The first RF generator 31a is configured to generate a source RF signal for plasma generation.

[0049] In one embodiment, the second RF generator 31b is electrically connected to at least one lower electrode of the substrate support 11 via a transmission line L2. At least one impedance matching circuit is provided on the transmission line L2. The second RF generator 31b is configured to generate a bias RF signal. Note that at least one of the source RF signal and the bias RF signal may be pulsed.

[0050] In one embodiment, the first DC generator 32a is electrically connected to at least one lower electrode of the substrate support 11 via a transmission line L3. When a plurality of lower electrodes are provided, the first DC generator 32a may be electrically connected to the same lower electrode as the second RF generator 31b, or may be electrically connected to a lower electrode different from the second RF generator 31b. The first DC generator 32a is configured to generate a first DC signal. The first DC signal may be pulsed. Note that in one embodiment, the first DC generator 32a may not be provided. Alternatively, in another embodiment, the second DC generator 32b may be connected to an upper electrode and configured to generate a second DC signal. The second DC signal may be pulsed.

[0051] <Configuration Example of Ceiling of Plasma Processing Apparatus 1> Figure 4 is a diagram illustrating a configuration example of the ceiling of the plasma processing apparatus 1. As shown in Figure 4, in one embodiment, the plasma processing apparatus 1 has a ceiling 14 above the plasma processing space 10s. The ceiling 14 is provided to close the opening of the chamber 10. That is, the ceiling 14 covers and blocks the opening at the upper end of the sidewall 10a of the chamber 10. A portion of the ceiling 14 is exposed to the plasma processing space 10s. In one embodiment, the sidewall 10a of the chamber 10 has a substantially cylindrical shape. The sidewall 10a of the chamber 10 may be connected to ground, and its potential may be set to the ground potential.

[0052] In one embodiment, the shower head 13, which constitutes a part of the ceiling part 14, includes at least one upper electrode 13d. The upper electrode 13d is part of the ceiling part 14 and is configured to receive a source RF signal. The upper electrode 13d is provided above the substrate support part 11. The upper electrode 13d is electrically connected to, for example, the first RF generator 31a.

[0053] In one embodiment, the upper electrode 13d includes a top plate 13e and a first support 13f. The top plate 13e has a substantially disk shape. The top plate 13e is in contact with the plasma processing space 10s. The top plate 13e may be made of a conductive material such as silicon, aluminum oxide, or quartz. The top plate 13e may be formed by forming a corrosion-resistant film on the surface of a conductive member such as aluminum. The corrosion-resistant film may be made of a material such as aluminum oxide or yttrium oxide.

[0054] In one embodiment, the first support 13f is provided on the top plate 13e. The first support 13f detachably supports the top plate 13e. The first support 13f may be formed of, for example, aluminum. The first support 13f provides at least one gas diffusion chamber 13b therein. The first support 13f, together with the top plate 13e, provides at least one gas inlet 13c. The at least one gas inlet 13c extends downward from the at least one gas diffusion chamber 13b and penetrates the top plate 13e.

[0055] In one embodiment, the ceiling portion 14 further includes a first insulating member 41. The first insulating member 41 is part of the ceiling portion 14. The first insulating member 41 is provided between the upper electrode 13d and the chamber 10. The first insulating member 41 electrically separates the upper electrode 13d from the chamber 10. The first insulating member 41 is provided on the outer side (the sidewall 10a side) of the upper electrode 13d. The first insulating member 41 has a substantially ring shape and extends in the circumferential direction to surround the upper electrode 13d. The first insulating member 41 may be formed from an insulator such as quartz.

[0056] In one embodiment, the ceiling portion 14 further includes an annular member 42. The annular member 42 may be substantially annular. The annular member 42 is another part of the ceiling portion 14 and is conductive. The annular member 42 is formed, for example, from a silicon-containing material. The annular member 42 extends from the periphery of the upper electrode 13d to the chamber 10. The annular member 42 is located below the first support 13f and extends in the circumferential direction to surround the periphery of the ceiling plate 13e. The annular member 42 is insulated from the upper electrode 13d and electrically floating relative to the upper electrode 13d. In the example shown in FIG. 4 , the annular member 42 is provided slightly spaced apart from the upper electrode 13d (the first support 13f and the ceiling plate 13e). Note that an insulating member may be provided between the annular member 42 and the first support 13f.

[0057] In one embodiment, the portion of the ceiling 14 exposed to the plasma processing space 10s may be composed of a conductor including the upper electrode 13d and the annular member 42. For example, the portion of the ceiling 14 exposed to the plasma processing space 10s may be composed only of a conductor. Hereinafter, the portion of the ceiling 14 exposed to the plasma processing space 10s will be referred to as the "exposed portion of the ceiling 14." In the example shown in FIG. 4 , the exposed portion of the ceiling 14 is composed only of the upper electrode 13d (top plate 13e) and the annular member 42. The annular member 42 is provided, for example, below the first insulating member 41. The annular member 42 extends so as not to expose the first insulating member 41 to the plasma processing space 10s. In the example shown in FIG. 4 , the annular member 42 is provided below a portion of the first support 13f, the first insulating member 41, and a portion of the second insulating member 44 described below.

[0058] In one embodiment, the entire area of ​​the exposed portion of the ceiling part 14 may be formed from a conductive material. In this case, reaction products adhering to the exposed portion can be removed by an electric bias during a cleaning process such as dry cleaning. As a result, the reaction products can be prevented from adhering as particles onto the substrate W.

[0059] In one embodiment, the chamber 10 further includes a second support 43. The second support 43 is provided outside the first insulating member 41 and above the annular member 42. The second support 43 is provided slightly spaced apart from the annular member 42. The second support 43 is provided on the sidewall 10a of the chamber 10. The second support 43 is electrically connected to the sidewall 10a of the chamber 10. The potential of the second support 43 is set to ground potential. The first insulating member 41 is provided between the first support 13f of the upper electrode 13d and the second support 43. The second support 43 is substantially annular and extends in the circumferential direction to surround the first insulating member 41. The second support 43 may be formed of a metal such as aluminum.

[0060] In one embodiment, the plasma processing apparatus 1 further includes at least one second insulating member 44. The at least one second insulating member 44 is provided outside the first insulating member 41 and on the annular member 42. The at least one second insulating member 44 is interposed between the chamber 10 and the annular member 42. In the example shown in FIG. 4 , the at least one second insulating member 44 is provided so that its lower surface contacts the outer upper surface of the annular member 42. The at least one second insulating member 44 is provided between the annular member 42 and the second support 43. The at least one second insulating member 44 is, for example, a plate-shaped member having a substantially annular shape. The at least one second insulating member 44 is formed from an insulator such as insulating ceramics, quartz, or metal oxide. Note that the second insulating member 44 may be integrally formed with the first insulating member 41 as part of the ceiling portion 14.

[0061] In one embodiment, the plasma processing apparatus 1 further includes at least one third insulating member 45. The at least one third insulating member 45 is provided below the annular member 42. The at least one third insulating member 45 is interposed between the chamber 10 and the annular member 42. The annular member 42 is supported between the at least one second insulating member 44 and the at least one third insulating member 45.

[0062] 4, the at least one third insulating member 45 includes a third support 45a and a sealing member 45b. The third support 45a is provided on the sidewall 10a. The third support 45a supports the annular member 42 from below. A portion of the inner surface of the third support 45a may be exposed to the plasma processing space 10s below the ceiling 14. The sealing member 45b is provided between the annular member 42 and the third support 45a. The sealing member 45b is arranged so as to contact outer portions of the annular member 42 and the third support 45a. The sealing member 45b is, for example, an O-ring that separates a reduced-pressure environment including the plasma processing space 10s from an atmospheric pressure environment.

[0063] The paths through which the current flows based on the RF power supplied to the upper electrode 13d include at least a first path that does not pass through the plasma and a second path that passes through the plasma. In the first path, the current flows from the upper electrode 13d to the sidewall 10a via the annular member 42, at least one second insulating member 44, and the second support 43. In the second path, the current flows from the upper electrode 13d to the sidewall 10a via the plasma in the plasma processing space 10s. The at least one second insulating member 44 reduces the electrostatic capacitance between the annular member 42 and the second support 43, thereby increasing the impedance of the first path.

[0064] In one embodiment, the inner wall portion 10t of the sidewall 10a (the portion facing the plasma processing space 10s) may be made of silicon. In this case, the inner wall portion 10t can serve as a counter electrode for the annular member 42. That is, at least a portion of the current flowing through the annular member 42 can flow to the sidewall 10a via the plasma in the plasma processing space 10s and the inner wall portion 10t.

[0065] In one embodiment, the plasma processing apparatus 1 further includes a switching circuit 50. The switching circuit 50 is electrically connected to the annular member 42. The switching circuit 50 may be provided outside the chamber 10. Details of the switching circuit 50 will be described later with reference to FIGS. 6 to 9. In the example shown in FIG. 4, the switching circuit 50 is electrically connected to the annular member 42 via a connection portion 48 and a conductive cable EL (hereinafter, the electrical connection lines between the annular member 42 and the switching circuit 50 will also be collectively referred to as the "connection line CL"). The connection portion 48 includes a connection ring RG and a connection pin PN.

[0066] The connection ring RG is made of a conductive material. The connection ring RG may be, for example, an annular body. The connection ring RG may be provided in a space inside the second support 43. The pressure in this space may be different from that of the plasma processing space 10s of the chamber 10 (for example, atmospheric pressure).

[0067] The connection pins PN are made of a metal material. The connection pins PN may be, for example, rod-shaped. The upper ends of the connection pins PN are connected to the connection ring RG. The connection pins PN extend downward from the upper ends, penetrate the second support 43 and the second insulating member 44, and connect to a radially outer portion of the annular member 42 at the lower ends. The outer portion may be a portion that is not exposed to the plasma processing space 10s. A seal member may be provided around the connection pins PN. The connection pins PN may have sufficient rigidity to seal the space inside the second support 43 and the plasma processing space 10s together with the seal member.

[0068] FIG. 5 is a diagram illustrating an example of a connection between the annular member 42 and the switching circuit 50. In the example shown in FIG. 5, a plurality of connection pins PN are provided between the annular member 42 and the connection ring RG. The plurality of connection pins PN are arranged at equal intervals along the circumferential direction of the annular member 42. The plurality of connection pins PN may include, for example, 4 to 12 connection pins. That is, the number of the plurality of connection pins PN may be 4 to 12. The connection ring RG is provided above the annular member 42 and parallel to the annular member 42. A conductive cable EL is connected to the connection ring RG. The conductive cable EL is connected to the switching circuit 50. The conductive cable EL may be, for example, a conductor wire, a coaxial cable, or a combination thereof.

[0069] 5, the current flowing through the annular member 42 flows to the connection ring RG via each connection pin PN, is collected by the connection ring RG, and flows to the switching circuit 50 via the conductive cable EL. This allows the current from the annular member 42 to be efficiently transmitted to the switching circuit 50. Note that when current flows from the switching circuit 50 to the annular member 42, the path is reversed.

[0070] The connection pins PN are made of a metal material and can function as antennas. In the example shown in Fig. 5, multiple connection pins PN are arranged at equal intervals along the circumferential direction, so even if each connection pin functions as an antenna, the RF signal supplied to the chamber 10 can be prevented from being biased to any one side in the radial direction. This can prevent the plasma generated in the chamber 10 from becoming non-uniform in the radial direction.

[0071] 6A and 6B are diagrams illustrating a first example configuration of the switching circuit 50. In one embodiment, the switching circuit 50 is configured to select a first state or a second state. The first state is a state in which the annular member 42 is electrically floating. The second state is a state in which the annular member 42 is electrically connected to ground potential.

[0072] Fig. 6A is an example of the first state. Fig. 6B is an example of the second state. As shown in Figs. 6A and 6B , the switching circuit 50 may include a first switch S1. The first switch S1 is configured to switch the connection destination of the annular member 42 and the connection line CL between the floating line FL and the ground line GL. The switching of the first switch S1 may be controlled by the control unit 2.

[0073] 6A , the connection line CL is electrically connected to the electrically floating floating line FL by the first switch S1 of the switching circuit 50. In this state, the annular member 42 is electrically floating. That is, the annular member 42 has a floating potential that is different from the potential of the upper electrode 13 d and the potential of the chamber 10.

[0074] 6B , the connection line CL is electrically connected to a ground line GL, which is connected to ground (ground potential), by a first switch S1 of the switching circuit 50. In this state, the annular member 42 is electrically connected to ground (ground potential). That is, the annular member 42 has the ground potential.

[0075] In one embodiment, the control unit 2 may control the first switch S1 to select the first state ( FIG. 6A ) during plasma processing of a substrate on the substrate support 11 in the chamber 10. Because the annular member 42 is at a floating potential, RF power supplied to the upper electrode 13d can be efficiently supplied to plasma in the plasma processing space 10s during substrate processing in the chamber 10. Furthermore, RF power supplied to the upper electrode 13d can be efficiently supplied to plasma even below the annular member 42. In one embodiment, the source RF signal supplied to the upper electrode 13d during plasma processing has an RF frequency of 60 MHz or higher. In one embodiment, the at least one bias signal generated by the bias generation unit during plasma processing has a bias frequency of 13 MHz or lower. The bias generation unit is electrically connected to the lower electrode. The at least one bias signal includes a bias RF signal and / or a voltage pulse signal. In one embodiment, the at least one bias signal includes a sequence of voltage pulses having a frequency within a range of 100 kHz to 1 MHz.

[0076] In one embodiment, the control unit 2 may control the first switch S1 to select the second state ( FIG. 6B ) during a cleaning process performed in the chamber 10. In one embodiment, the source RF signal supplied to the upper electrode 13d during the cleaning process has an RF frequency of 60 MHz or more. In one embodiment, the at least one bias signal generated by the bias generation unit during the cleaning process has a bias frequency of 13 MHz or less. The bias generation unit is electrically connected to the lower electrode. The at least one bias signal includes a bias RF signal and / or a voltage pulse signal. In one embodiment, the at least one bias signal includes a sequence of voltage pulses having a frequency within a range of 100 kHz to 1 MHz. Because the annular member 42 is at ground potential, an electric bias can be efficiently supplied to the annular member 42 via the upper electrode 13d during the cleaning process. This allows reaction products (e.g., metal inclusions) attached to exposed portions of the annular member 42 during plasma processing of a substrate to be removed. As a result, the reaction products can be prevented from adhering as particles to the substrate during subsequent plasma processing.

[0077] 7 is a diagram illustrating a second configuration example of the switching circuit 50. In one embodiment, the switching circuit 50 is configured to select a third state in addition to the first and second states described above. The third state is a state in which the annular member 42 is electrically connected to the ground potential via the impedance adjustment circuit.

[0078] 7, the switching circuit 50 may include a second switch S2. The second switch S2 is configured to switch the connection destination of the annular member 42 and the connection line CL between the floating line FL, the ground line GL, and the impedance adjustment line AL. The switching of the second switch S2 may be controlled by the control unit 2. The floating line FL and the ground line GL are similar to those in the first configuration example, and a description thereof will be omitted.

[0079] In one embodiment, the impedance adjustment circuit AL is electrically connected to ground (ground potential) via an impedance adjustment circuit 52. The impedance adjustment circuit 52 is configured to be able to adjust the impedance on the input side (the annular member 42 side). The impedance adjustment circuit 52 may be controlled by, for example, the control unit 2.

[0080] 8A to 8G are diagrams illustrating configuration examples of the impedance adjustment circuit 52. As shown in (A) to (G) of Fig. 8, the impedance adjustment circuit 52 may be configured as a circuit in which reactance elements (such as a fixed coil FR, a variable coil VR, a fixed capacitor FC, and a variable capacitor VC) are appropriately combined.

[0081] 8A shows a circuit in which a fixed coil FR and a variable capacitor VC are connected in series in this order from the input side (annular member 42 side) to the output side (ground side). In this circuit, the impedance of the input side (annular member 42 side) can be adjusted by changing the capacitance of the variable capacitor VC. Note that the connection order of the variable capacitor VC and the fixed coil FR may be reversed.

[0082] 8B shows a circuit in which a variable coil VR whose inductance can be changed and a fixed capacitor FC are connected in series. Note that a variable capacitor VC may be provided in place of this fixed capacitor FC.

[0083] Fig. 8(C) shows a circuit in which a variable capacitor VC and a fixed coil FR are connected in series and then in parallel with the fixed coil FR. Fig. 8(D) shows a circuit in which a series circuit of a variable capacitor VC and a fixed capacitor FC is connected in parallel with the fixed capacitor FC. Fig. 8(E) shows a circuit in which a parallel connection circuit of a fixed capacitor FC and a fixed coil FR is connected in series with another fixed capacitor FC and a variable coil VR in that order.

[0084] FIG. 8F shows a circuit in which switches SW are connected in series to a plurality of fixed capacitors FC, and the capacitance is changed in stages by switching these switches on and off in any combination.

[0085] 8(G) shows a circuit in which switches SW are connected in series to multiple fixed coils FR, and the inductance is changed in stages by switching these switches SW on and off in any combination, and further combined with a variable capacitor VC. In this circuit, fine adjustment can be made with the variable capacitor VC, and coarse adjustment can be made by switching the fixed coils FR.

[0086] In one embodiment, the control unit 2 may control the second switch S2 to select the first state or the third state while plasma processing is being performed on the substrate on the substrate support 11 in the chamber 10. When the first state is selected, the same process as described in the first configuration example will not be repeated.

[0087] When the third state is selected, a portion of the current based on the RF power supplied to the upper electrode 13d flows from the annular member 42 to the impedance adjustment line AL via the switching circuit 50. The impedance on the annular member 42 side is adjusted by the impedance adjustment circuit 52, thereby adjusting the current flowing from the upper electrode 13d to the annular member 42. As a result, the RF power supplied from the upper electrode 13d to the plasma in the plasma processing space 10s can be adjusted. This allows the RF power supplied to the plasma in the plasma processing space 10s to be adjusted, for example, without changing the output of the source RF signal supplied from the first RF generator 31a to the upper electrode 13d.

[0088] In one embodiment, the control unit 2 may control the second switch S2 to select the second state while the cleaning process is being performed in the chamber 10. When the second state is selected, the same process as described in the first configuration example is performed, and therefore further description will be omitted.

[0089] <Third Configuration Example of Switching Circuit 50> Figure 9 is a diagram illustrating a third configuration example of the switching circuit 50. In one embodiment, the switching circuit 50 is configured to select a fourth state in addition to the first to third states described above. The fourth state is a state in which the annular member 42 is electrically connected to a DC power supply.

[0090] 9 , the switching circuit 50 may include a third switch S3. The third switch S3 is configured to switch the connection destination of the annular member 42 and the connection line CL between the floating line FL, the ground line GL, the impedance adjustment line AL, and the DC power supply line DL. The switching of the third switch S3 may be controlled by the control unit 2. The floating line FL, the ground line GL, and the impedance adjustment line AL are the same as those in the first or second configuration example, and therefore a description thereof will be omitted.

[0091] In one embodiment, the DC power supply line DL includes an RF filter 54 and a DC power supply 56. The RF filter 54 blocks or attenuates an RF signal flowing through the DC power supply line DL to prevent the RF signal from entering the DC power supply 56. The DC power supply 56 is configured to generate a third DC signal. In one embodiment, the third DC signal may have a negative polarity. In one embodiment, the third DC signal may be pulsed.

[0092] In one embodiment, the control unit 2 may control the third switch S3 to select the first state or the third state while plasma processing is being performed on the substrate on the substrate support 11 in the chamber 10. When the first state or the third state is selected, the same process as described in the first or second configuration example is performed, and therefore further description will be omitted.

[0093] In one embodiment, the controller 2 may control the third switch S3 to select the second state or the fourth state while a cleaning process is being performed in the chamber 10. When the second state is selected, the process is the same as that described in the first configuration example, and therefore further description will be omitted. When the fourth state is selected, an electric bias (third DC signal) may be directly supplied to the annular member 42 via the DC power supply 56. This may more efficiently remove reaction products (e.g., metal inclusions) that adhere to exposed portions of the annular member 42 during plasma processing of a substrate, etc. As a result, the reaction products may be prevented from adhering as particles to the substrate in subsequent plasma processing.

[0094] According to one embodiment, a technique for adjusting the potential of the ceiling of a plasma processing apparatus can be provided.

[0095] <Modifications> Although various exemplary embodiments have been described above, the present disclosure is not limited to the above-described embodiments, and various additions, omissions, substitutions, and modifications may be made. Furthermore, elements of different embodiments may be combined to form other embodiments. For example, in the first to third configuration examples, a VI sensor that detects the current or voltage flowing through the connection line CL between the annular member 42 and the switching circuit 50 may be provided in the connection line CL. The control unit 2 may detect the state of the annular member 42 by monitoring the output of the VI sensor. For example, when the connection line CL is electrically connected to the ground line GL, the control unit 2 may detect the presence or amount of deposits adhering to the annular member 42 by monitoring the output of the VI sensor.

[0096] Embodiments of the present disclosure further include the following aspects.

[0097] (Supplementary Note 1) A plasma processing apparatus comprising: a plasma processing chamber; a substrate support disposed within the plasma processing chamber; an upper electrode disposed above the substrate support; a conductive annular member disposed to surround the upper electrode; an RF power supply electrically connected to the upper electrode; and a switching circuit electrically connected to the annular member, the switching circuit configured to select a first state during plasma processing of a substrate on the substrate support and to select a second state during a cleaning process in the chamber, wherein the annular member is electrically floating in the first state and is electrically connected to a ground potential in the second state.

[0098] (Supplementary Note 2) The plasma processing apparatus according to Supplementary Note 1, wherein the annular member is insulated from the upper electrode.

[0099] (Supplementary Note 3) The plasma processing apparatus according to Supplementary Note 1 or Supplementary Note 2, wherein the annular member is exposed to a plasma processing space in the plasma processing chamber.

[0100] (Supplementary Note 4) The plasma processing apparatus according to any one of Supplementary Note 1 to Supplementary Note 3, wherein the annular member is made of silicon.

[0101] (Supplementary Note 5) The plasma processing apparatus described in any one of Supplementary Note 1 to Supplementary Note 4, further comprising: a lower electrode disposed within the substrate support; and a bias generation unit electrically connected to the lower electrode, wherein the RF power supply is configured to generate an RF signal having an RF frequency of 60 MHz or more during the cleaning process, and the bias generation unit is configured to generate at least one bias signal having a bias frequency of 13 MHz or less.

[0102] (Supplementary Note 6) The plasma processing apparatus according to Supplementary Note 5, wherein the at least one bias signal includes a bias RF signal and / or a voltage pulse signal.

[0103] (Supplementary Note 7) The plasma processing apparatus of Supplementary Note 5, wherein the at least one bias signal includes a sequence of voltage pulses having a frequency in the range of 100 kHz to 1 MHz.

[0104] (Supplementary Note 8) The plasma processing apparatus according to any one of Supplementary Note 1 to Supplementary Note 7, further comprising a plurality of connection pins, wherein the switching circuit is connected to the annular member via the plurality of connection pins.

[0105] (Supplementary Note 9) The plasma processing apparatus according to Supplementary Note 8, wherein the plurality of connection pins are arranged at equal intervals in a circumferential direction along the annular member.

[0106] (Supplementary Note 10) The plasma processing apparatus according to Supplementary Note 8 or Supplementary Note 9, wherein the plurality of connection pins include 4 to 12 connection pins.

[0107] (Supplementary Note 11) The plasma processing apparatus according to any one of Supplementary Note 8 to Supplementary Note 10, further comprising a conductive connection ring, the connection ring being electrically connected between the plurality of connection pins and the switching circuit.

[0108] (Supplementary Note 12) A plasma processing apparatus comprising: a plasma processing chamber; a substrate support disposed within the plasma processing chamber; an upper electrode disposed above the substrate support; a conductive annular member disposed to surround the upper electrode; an RF power supply electrically connected to the upper electrode; and a switching circuit electrically connected to the annular member, the switching circuit configured to select a first state, a second state, or a third state, wherein in the first state the annular member is electrically floating, in the second state the annular member is electrically connected to a ground potential, and in the third state the annular member is electrically connected to the ground potential via an impedance adjustment circuit.

[0109] (Supplementary Note 13) The plasma processing apparatus according to Supplementary Note 12, wherein the annular member is insulated from the upper electrode.

[0110] (Supplementary Note 14) The plasma processing apparatus according to Supplementary Note 12 or Supplementary Note 13, wherein the annular member is exposed to a plasma processing space in the plasma processing chamber.

[0111] (Supplementary Note 15) The plasma processing apparatus according to any one of Supplementary Note 9 to Supplementary Note 11, wherein the annular member is made of silicon.

[0112] (Supplementary Note 16) The plasma processing apparatus according to any one of Supplementary Note 12 to Supplementary Note 15, further comprising a plurality of connection pins, wherein the switching circuit is connected to the annular member via the plurality of connection pins.

[0113] (Supplementary Note 17) The plasma processing apparatus according to Supplementary Note 16, wherein the plurality of connection pins are arranged at equal intervals in a circumferential direction along the annular member.

[0114] (Supplementary Note 18) The plasma processing apparatus according to Supplementary Note 16 or Supplementary Note 17, wherein the plurality of connection pins include 4 to 12 connection pins.

[0115] (Supplementary Note 19) The plasma processing apparatus according to any one of Supplementary Note 16 to Supplementary Note 18, further comprising a conductive connection ring, the connection ring being electrically connected between the plurality of connection pins and the switching circuit.

[0116] (Supplementary Note 20) The plasma processing apparatus according to any one of Supplementary Note 12 to Supplementary Note 19, further comprising a DC power supply, wherein the switching circuit is configured to select the first state, the second state, the third state, or a fourth state, and in the fourth state, the annular member is electrically connected to the DC power supply.

[0117] 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.

[0118] 1: Plasma processing apparatus, 2: Control unit, 10: Plasma processing chamber, 10s: Plasma processing space, 11: Substrate support unit, 13d: Upper electrode, 14: Ceiling unit, 31a: First RF generating unit, 42: Annular member, 50: Switching circuit, AL: Impedance adjustment line, CL: Connection line, DL: DC power supply line, FL: Floating line, GL: Ground line

Claims

1. A plasma processing apparatus comprising: a plasma processing chamber; a substrate support disposed within the plasma processing chamber; an upper electrode disposed above the substrate support; a conductive annular member disposed surrounding the upper electrode; an RF power supply electrically connected to the upper electrode; and a switching circuit electrically connected to the annular member, the switching circuit configured to select a first state during plasma processing of a substrate on the substrate support and to select a second state during a cleaning process in the chamber, wherein in the first state the annular member is electrically floating and in the second state the annular member is electrically connected to ground potential.

2. The plasma processing apparatus of claim 1, wherein said annular member is insulated from said upper electrode.

3. The plasma processing apparatus of claim 2, wherein the annular member is exposed to a plasma processing space within the plasma processing chamber.

4. The plasma processing apparatus according to claim 3, wherein said annular member is made of silicon.

5. The plasma processing apparatus of claim 4, further comprising: a lower electrode disposed within the substrate support; and a bias generation unit electrically connected to the lower electrode, wherein the RF power supply is configured to generate an RF signal having an RF frequency of 60 MHz or more during the cleaning process, and the bias generation unit is configured to generate at least one bias signal having a bias frequency of 13 MHz or less.

6. The plasma processing apparatus of claim 5, wherein the at least one bias signal comprises a bias RF signal and / or a voltage pulse signal.

7. The plasma processing apparatus of claim 5, wherein the at least one bias signal comprises a sequence of voltage pulses having a frequency in the range of 100 kHz to 1 MHz.

8. The plasma processing apparatus according to any one of claims 1 to 7, further comprising a plurality of connection pins, wherein the switching circuit is connected to the annular member via the plurality of connection pins.

9. The plasma processing apparatus according to claim 8, wherein the plurality of connection pins are arranged at equal intervals in the circumferential direction along the annular member.

10. The plasma processing apparatus according to claim 9, wherein the plurality of connection pins includes 4 to 12 connection pins.

11. The plasma processing apparatus of claim 10, further comprising a conductive connecting ring, said connecting ring being electrically connected between said plurality of connecting pins and said switching circuit.

12. A plasma processing apparatus comprising: a plasma processing chamber; a substrate support disposed within the plasma processing chamber; an upper electrode disposed above the substrate support; a conductive annular member disposed to surround the upper electrode; an RF power supply electrically connected to the upper electrode; and a switching circuit electrically connected to the annular member, the switching circuit configured to select a first state, a second state, or a third state, wherein in the first state the annular member is electrically floating, in the second state the annular member is electrically connected to a ground potential, and in the third state the annular member is electrically connected to the ground potential via an impedance adjustment circuit.

13. The plasma processing apparatus of claim 12, wherein the annular member is insulated from the upper electrode.

14. The plasma processing apparatus of claim 12, wherein the annular member is exposed to a plasma processing volume within the plasma processing chamber.

15. The plasma processing apparatus of claim 14, wherein the annular member is formed of silicon.

16. The plasma processing apparatus according to any one of claims 12 to 15, further comprising a plurality of connection pins, wherein the switching circuit is connected to the annular member via the plurality of connection pins.

17. The plasma processing apparatus according to claim 16, wherein the plurality of connection pins are arranged at equal intervals in the circumferential direction along the annular member.

18. The plasma processing apparatus according to claim 17, wherein the plurality of connection pins includes 4 to 12 connection pins.

19. The plasma processing apparatus of claim 18, further comprising a conductive connecting ring, said connecting ring being electrically connected between said plurality of connecting pins and said switching circuit.

20. A plasma processing apparatus according to any one of claims 12 to 15, further comprising a DC power supply, wherein the switching circuit is configured to select the first state, the second state, the third state, or a fourth state, and in the fourth state, the annular member is electrically connected to the DC power supply.

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