Plasma processing device

Abstract

This plasma processing device comprises: a plasma processing chamber; a variable impedance element; a substrate support part that is disposed in the plasma processing chamber and is provided with a conductive base, an electrostatic chuck, an edge ring, a substrate bias electrode, a ring bias electrode, an additional electrode electrically connected to a ground potential via the variable impedance element, and at least one connector electrically connecting the edge ring and the conductive base; and at least one voltage pulse generation unit electrically connected to the substrate bias electrode and the ring bias electrode and configured to generate a pulsed voltage signal.

Description

Plasma processing equipment

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

[0002] Patent Document 1 describes a technique in which a variable impedance circuit is provided on a second electrical path that supplies power from a matching circuit to a focus ring. Patent Document 2 describes a technique in which a variable capacitor is connected to a wire that connects an annular electrode and a conductive base.

[0003] JP 2020-96176 A U.S. Patent Application Publication No. 2019 / 0006155

[0004] The present disclosure provides a technique that can adjust the potential of the edge ring.

[0005] In one exemplary embodiment of the present disclosure, a plasma processing apparatus includes: a plasma processing chamber; a variable impedance element; a substrate support disposed within the plasma processing chamber, the substrate support including: a conductive base; an electrostatic chuck disposed on the conductive base and having a substrate support surface and a ring support surface; an edge ring disposed on the ring support surface to surround a substrate disposed on the substrate support surface; a substrate bias electrode disposed within the electrostatic chuck below the substrate support surface; a ring bias electrode disposed within the electrostatic chuck below the ring support surface; an additional electrode disposed within the electrostatic chuck between the ring support surface and the ring bias electrode, the additional electrode being electrically connected to ground potential via the variable impedance element; and at least one voltage pulse generator electrically connected to the substrate bias electrode and the ring bias electrode and configured to generate a pulsed voltage signal.

[0006] According to one exemplary embodiment of the present disclosure, a technique for adjusting the potential of an edge ring 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 plasma processing apparatus. FIG. 3 is a diagram for explaining an example of the configuration of a substrate support and an electric circuit. FIG. 4 is a diagram for explaining an example of the configuration of a connector. FIG. 5 is a diagram showing an example of a pulsed voltage signal. FIG. 6 is a diagram for explaining another example of the configuration of a substrate support and an electric circuit. FIG. 7 is a diagram for explaining another example of the configuration of a substrate support and an electric circuit. FIG. 8 is a diagram for explaining another example of the configuration of a substrate support and an electric 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 variable impedance element; a substrate support disposed within the plasma processing chamber, the substrate support including: a conductive base; an electrostatic chuck disposed on the conductive base and having a substrate support surface and a ring support surface; an edge ring disposed on the ring support surface to surround a substrate disposed on the substrate support surface; a substrate bias electrode disposed within the electrostatic chuck below the substrate support surface; a ring bias electrode disposed within the electrostatic chuck below the ring support surface; an additional electrode disposed within the electrostatic chuck between the ring support surface and the ring bias electrode, the additional electrode being electrically connected to ground potential via the variable impedance element; and at least one voltage pulse generator electrically connected to the substrate bias electrode and the ring bias electrode and configured to generate a pulsed voltage signal.

[0010] In one exemplary embodiment, the at least one voltage pulse generator is electrically connected to the substrate bias electrode and the ring bias electrode through the conductive base.

[0011] In one exemplary embodiment, the at least one voltage pulse generator includes a first voltage pulse generator electrically connected to the substrate bias electrode and configured to generate a first pulsed voltage signal, and a second voltage pulse generator electrically connected to the ring bias electrode and configured to generate a second pulsed voltage signal.

[0012] In one exemplary embodiment, the substrate support includes a substrate chucking electrode disposed between the substrate bias electrode and the substrate support surface within the electrostatic chuck.

[0013] In one exemplary embodiment, the substrate support includes a ring chuck electrode, which is positioned between the ring support surface and the additional electrode within the electrostatic chuck.

[0014] In one exemplary embodiment, a plasma processing apparatus is provided, comprising: a plasma processing chamber; a variable impedance element; a substrate support disposed within the plasma processing chamber, the substrate support including: a conductive base; an electrostatic chuck disposed on the conductive base and having a substrate support surface and a ring support surface; an edge ring disposed on the ring support surface to surround a substrate disposed on the substrate support surface; a substrate bias electrode disposed within the electrostatic chuck below the substrate support surface; a ring bias electrode disposed within the electrostatic chuck below the ring support surface; an additional electrode disposed within the electrostatic chuck between the ring support surface and the ring bias electrode, the additional electrode being electrically connected to ground potential via the variable impedance element; and at least one RF generator electrically connected to the substrate bias electrode and the ring bias electrode and configured to generate an RF signal.

[0015] In one exemplary embodiment, the at least one RF generator is electrically connected to the substrate bias electrode and the ring bias electrode through a conductive pedestal.

[0016] In one exemplary embodiment, the at least one RF generator includes a first RF generator electrically connected to the substrate bias electrode and a second RF generator electrically connected to the ring bias electrode.

[0017] In one exemplary embodiment, the substrate support includes a substrate chucking electrode disposed between the substrate electrode and the substrate support surface within the electrostatic chuck.

[0018] In one exemplary embodiment, the substrate support includes a ring chuck electrode, which is positioned between the ring support surface and the additional electrode within the electrostatic chuck.

[0019] 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.

[0020] <Example of Plasma Processing System> FIG. 1 is a diagram illustrating an example of the configuration of a plasma processing system. In one embodiment, the plasma processing system includes a plasma 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.

[0021] 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.

[0022] 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).

[0023] The following describes a configuration example of a capacitively coupled plasma processing apparatus as an example of the plasma processing apparatus 1. FIG.

[0024] The capacitively coupled plasma processing apparatus 1 includes a plasma processing chamber 10 (also simply referred to as the "chamber"), a gas supply unit 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.

[0025] 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.

[0026] In one embodiment, the main body 111 includes a base 1110 (also referred to as a "conductive base") 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] In one embodiment, the RF power supply 31 includes a first RF generating unit 31a and a second RF generating unit 31b. The first RF generating unit 31a is coupled to at least one lower electrode and / or at least one upper electrode via at least one impedance matching circuit and is configured to generate a source RF signal (source RF power) for plasma generation. In one embodiment, the source RF signal has a frequency in the range of 10 MHz to 150 MHz. In one embodiment, the first RF generating unit 31a may be configured to generate 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.

[0033] 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.

[0034] The power supply 30 may also include a DC power supply 32 coupled to the plasma processing chamber 10. The DC power supply 32 includes a first DC generator 32a and a second DC generator 32b. In one embodiment, the first DC generator 32a is connected to 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.

[0035] 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.

[0036] The exhaust system 40 may be connected to, for example, a gas exhaust port 10e provided at the bottom of the plasma processing chamber 10. The exhaust system 40 may include a pressure regulating valve and a vacuum pump. The pressure in the plasma processing space 10s is regulated by the pressure regulating valve. The vacuum pump may include a turbomolecular pump, a dry pump, or a combination thereof.

[0037] 3 is a diagram illustrating an example of the configuration of the substrate support 11 and an electrical circuit according to an embodiment. In the embodiment, the substrate support 11 may include a conductive base 1110, an electrostatic chuck 1111, an edge ring 200, a substrate bias electrode 201, a ring bias electrode 202, an additional electrode 203, and a connector 204.

[0038] In one embodiment, the electrostatic chuck 1111 may include, on its upper surface, a substrate support surface 210a and a ring support surface 210b disposed to surround the substrate support surface 210a. The substrate support surface 210a may be an example of the central region 111a shown in FIG. 2. The ring support surface 210b may be an example of the annular region 111b shown in FIG. 2.

[0039] 3, the edge ring 200 may be disposed on the ring support surface 210b to surround the substrate W disposed on the substrate support surface 210a. The edge ring 200 may be conductive. The height of the upper surface of the edge ring 200 may be the same as or higher than the height of the upper surface of the substrate W disposed on the substrate support surface 210a. The edge ring 200 may be included in the ring assembly 112 shown in FIG.

[0040] 3, the substrate bias electrode 201 may be disposed within the electrostatic chuck 1111. The substrate bias electrode 201 may be disposed below the substrate support surface 210a. The substrate bias electrode 201 may be electrically connected to the conductive base 1110 via a first conductor 220. The substrate bias electrode 201 may have a circular shape. The substrate bias electrode 201 may be disposed so that its center coincides with that of the electrostatic chuck 1111 in a plan view.

[0041] The ring bias electrode 202 may be disposed within the electrostatic chuck 1111. The ring bias electrode 202 may be disposed below the ring support surface 210b. The ring bias electrode 202 may be electrically connected to the conductive base 1110 via a first conductor 220. The ring bias electrode 202 may have an annular shape. The ring bias electrode 202 may be disposed so that its center coincides with that of the electrostatic chuck 1111 in a plan view.

[0042] The conductive base 1110 may be electrically connected to at least one voltage pulse generating unit 240 via a second conductor 221. The voltage pulse generating unit 240 may be configured to generate a pulsed voltage signal. The pulsed voltage signal may have a plurality of voltage pulses. The voltage pulse generating unit 240 may be electrically connected to the substrate bias electrode 201 and the ring bias electrode 202 via the second conductor 221, the conductive base 1110, and the first conductor 220. The voltage pulse generating unit 240 may be an example of the first DC generating unit 32a shown in FIG. 2 .

[0043] As shown in FIG. 3 , the additional electrode 203 may be disposed within the electrostatic chuck 1111. The additional electrode 203 may be disposed between the ring support surface 210b and the ring bias electrode 202. The additional electrode 203 may be electrically connected to a ground potential 250 via a third conductor 222. The ground potential 250 may be disposed outside the chamber 10. A variable impedance element 260 may be electrically connected to the third conductor 222. By adjusting the impedance of the variable impedance element 260, the potential of the edge ring 200 during plasma generation may be controlled. The impedance of the variable impedance element 260 may be adjusted by the control unit 2. The variable impedance element 260 may include a variable capacitor whose capacitance can be changed. The variable impedance element 260 may include at least one selected from a variable capacitor, a variable resistor, and a variable inductor. The additional electrode 203 may be electrically insulated from the conductive base 1110. The additional electrode 203 may have a circular ring shape. The additional electrode 203 may be arranged so that its center coincides with that of the electrostatic chuck 1111 in a plan view.

[0044] The connector 204 may electrically connect the edge ring 200 and the conductive base 1110. As shown in FIG. 4 , the connector 204 may include at least one annular conductive spring 280 and an annular conductive member 281. The at least one annular conductive spring 280 may include a first annular conductive spring 290 and a second annular conductive spring 291. The first annular conductive spring 290 may be arranged to contact the outer wall of the edge ring 200. The second annular conductive spring 291 may be arranged to contact the outer wall of the conductive base 1110. The annular conductive member 281 may be arranged outside the edge ring 200, the electrostatic chuck 1111, and the conductive base 1110. The annular conductive member 281 may contact the first annular conductive spring 290 and the second annular conductive spring 291 and electrically connect the first annular conductive spring 290 and the second annular conductive spring 291. The annular conductive member 281 may press the first annular conductive spring 290 against the outer wall of the edge ring 200. The annular conductive member 281 may press the second annular conductive spring 291 against the outer wall of the conductive base 1110. The annular conductive member 281 may be electrically insulated from the electrostatic chuck 1111. The annular conductive member 281 may be covered by an insulating annular member 292. The annular member 292 may hold the annular conductive member 281 and fix the annular conductive member 281 to a position outside the edge ring 200 and the conductive base 1110. The connector 204 may be one or more.

[0045] <Example of Plasma Processing Method> In one embodiment, the plasma processing method includes an etching process that uses plasma to etch a film on the substrate W. In one embodiment, the plasma processing method is performed by the control unit 2 in the plasma processing apparatus 1.

[0046] First, the substrate W is carried into the chamber 10 by the transport arm, placed on the substrate support 11 by the lifter, and held by suction on the substrate support 11 as shown in FIG.

[0047] Next, a processing gas is supplied to the shower head 13 by the gas supply unit 20, and is then supplied to the plasma processing space 10s from the shower head 13. The processing gas supplied at this time includes a gas that generates activated species necessary for etching the substrate W.

[0048] A source RF signal is supplied from an RF power supply 31 to the upper electrode or the lower electrode. A pulsed voltage signal is supplied from a DC power supply 32 to the lower electrode. The atmosphere in the plasma processing space 10s is exhausted from a gas exhaust port 10e, and the pressure inside the plasma processing space 10s is reduced. As a result, plasma is generated from the processing gas on the substrate support 11 in the plasma processing space 10s, and the substrate W is etched.

[0049] In one example of the etching process described above, during plasma generation, a pulsed voltage signal may be supplied from the voltage pulse generating unit 240 shown in FIG. 3 to the substrate bias electrode 201 and the ring bias electrode 202. As shown in FIG. 5, multiple voltage pulses included in the pulsed voltage signal may have a first voltage level V1 greater than the zero voltage level V0. The first voltage level V1 may have negative polarity. The pulsed voltage signal may be supplied from the voltage pulse generating unit 240 shown in FIG. 3 to the substrate bias electrode 201 and the ring bias electrode 202 via the second conductor 221, the conductive base 1110, and the first conductor 220. A current generated by the pulsed voltage signal may flow to the ground potential 250 via the second conductor 221, the conductive base 1110, the connector 204, the edge ring 200, the additional electrode 203, and the third conductor 222. At this time, the potential of the edge ring 200 may be controlled by adjusting the impedance of the variable impedance element 260. The potential of the edge ring 200 relative to the potential of the substrate W may be controlled to make the plasma sheath PS generated on the substrate W and the edge ring 200 closer to horizontal. As a result, plasma ions can be supplied perpendicular to the substrate W near the outer periphery of the substrate W. Therefore, the tilt angle (the angle of incidence of ions to the substrate W) can be maintained at 90°.

[0050] The impedance of the variable impedance element 260 may be adjusted based on the amount of wear of the edge ring 200. The amount of wear of the edge ring 200 may be determined based on the cumulative time during which the voltage pulse generating unit 240 supplies a pulsed voltage signal to the conductive base 1110, i.e., the operating time of the voltage pulse generating unit 240. The amount of wear of the edge ring 200 may be detected by a sensor or the like. As the amount of wear of the edge ring 200 increases, the potential of the edge ring 200 may be lowered. The impedance of the variable impedance element 260 may be adjusted before plasma is generated.

[0051] According to this exemplary embodiment, the plasma processing apparatus 1 includes a variable impedance element 260, an additional electrode 203 disposed between the ring support surface 210b and the ring bias electrode 202 in the electrostatic chuck 1111 and electrically connected to a ground potential 250 via the variable impedance element 260, at least one connector 204 electrically connecting the edge ring 200 and the conductive base 1110, and at least one voltage pulse generator 240. Thus, when the voltage pulse generator 240 supplies a pulsed voltage signal to the substrate bias electrode 201 and the ring bias electrode 202, the potential of the edge ring 200 can be adjusted by adjusting the impedance of the variable impedance element 260. As a result, the potential of the edge ring 200 can be adjusted in accordance with the wear rate of the edge ring 200, and the plasma sheath PS generated on the substrate W and the edge ring 200 can be maintained horizontal. Therefore, the tilt angle (the angle of incidence of ions with respect to the substrate W) can be maintained at 90° near the outer periphery of the substrate W.

[0052] In the above embodiment, as shown in FIG. 6 , at least one voltage pulse generating unit 240 may include a first voltage pulse generating unit 300 and a second voltage pulse generating unit 301. The first voltage pulse generating unit 300 may be electrically connected to the substrate bias electrode 201 and configured to generate a first pulsed voltage signal. The second voltage pulse generating unit 301 may be electrically connected to the ring bias electrode 202 and configured to generate a second pulsed voltage signal. The first voltage pulse generating unit 300 may be electrically connected to the substrate bias electrode 201 via a fourth conductor 310, not via the conductive base 1110. The second voltage pulse generating unit 301 may be electrically connected to the ring bias electrode 202 via a second conductor 221, the conductive base 1110, and the first conductor 220. During plasma processing, a first pulsed voltage signal may be supplied from the first voltage pulse generating unit 300 to the substrate bias electrode 201, and a second pulsed voltage signal may be supplied from the second voltage pulse generating unit 301 to the ring bias electrode 202.

[0053] In the above embodiment, as shown in FIG. 7, the substrate support 11 may further include at least one substrate chuck electrode 350 and at least one ring chuck electrode 351 .

[0054] At least one substrate chuck electrode 350 may be disposed between the substrate support surface 210 a and the substrate bias electrode 201 within the electrostatic chuck 1111. The substrate chuck electrode 350 may be electrically connected to a DC power supply 361 via a fifth conductor 360. A filter that suppresses RF signals or pulsed voltage signals from entering the DC power supply 361 may be electrically connected to the fifth conductor 360. The fifth conductor 360 may be electrically insulated from the conductive base 1110. When a DC voltage is applied from the DC power supply 361 to the substrate chuck electrode 350, an electrostatic attractive force (Coulomb force) is generated between the substrate chuck electrode 350 and the substrate W. The substrate W may be attracted to the electrostatic chuck 1111 by the electrostatic attractive force and adsorbed and held on the substrate support surface 210 a. The substrate chuck electrode 350 may include multiple substrate chuck electrodes. The substrate chuck electrode 350 may be an example of the electrostatic electrode 1111b shown in FIG.

[0055] 7, at least one ring chuck electrode 351 may be disposed between the ring support surface 210b and the additional electrode 203 within the electrostatic chuck 1111. The ring chuck electrode 351 may include an inner chuck electrode 370 and an outer chuck electrode 371.

[0056] The inner chuck electrode 370 and the outer chuck electrode 371 may have an annular shape. The inner chuck electrode 370 and the outer chuck electrode 371 may be arranged so that their centers coincide in a plan view. The inner chuck electrode 370 and the outer chuck electrode 371 may be arranged at the same position in the vertical direction.

[0057] The inner chuck electrode 370 may be electrically connected to a DC power supply 381 via a sixth conductor 380. The outer chuck electrode 371 may be electrically connected to a DC power supply 391 via a seventh conductor 390. The ring chuck electrode 351 may establish a potential difference between the inner chuck electrode 370 and the outer chuck electrode 371, and the edge ring 200 may be attracted and held to the ring support surface 210b by the potential difference. A filter that suppresses RF signals or pulsed voltage signals from entering the DC power supplies 381, 391 may be electrically connected to the sixth conductor 380 and the seventh conductor 390. The sixth conductor 380 and the seventh conductor 390 may be electrically insulated from the conductive base 1110. The ring chuck electrode 351 may include one chuck electrode or three or more chuck electrodes.

[0058] 8, the plasma processing apparatus 1 may include at least one RF generating unit 400 instead of the voltage pulse generating unit 240. The other configurations may be similar to those of the substrate support unit 11 and the electrical circuit shown in FIG.

[0059] As shown in FIG. 8 , at least one RF generator 400 may be electrically connected to the substrate bias electrode 201 and the ring bias electrode 202 via the second conductor 221, the conductive base 1110, and the first conductor 220. The RF generator 400 may be configured to generate an RF signal. The RF generator 400 may be configured to generate a bias RF signal. The bias RF signal may have a frequency in the range of 100 kHz to 60 MHz. The RF generator 400 may be configured to generate a source RF signal for plasma generation. The source RF signal may have a frequency in the range of 10 MHz to 150 MHz. The RF generator 400 may be an example of the second RF generator 31b shown in FIG. 2 .

[0060] 9 , at least one RF generating unit 400 may include a first RF generating unit 410 electrically connected to the substrate bias electrode 201 and a second RF generating unit 411 electrically connected to the ring bias electrode 202. The first RF generating unit 410 may be electrically connected to the substrate bias electrode 201 via an eighth conductor 420 without via the conductive base 1110. The second RF generating unit 411 may be electrically connected to the ring bias electrode 202 via a second conductor 221, the conductive base 1110, and the first conductor 220. During plasma processing, a first RF signal may be supplied from the first RF generating unit 410 to the substrate bias electrode 201, and a second RF signal may be supplied from the second RF generating unit 411 to the ring bias electrode 202.

[0061] The plasma processing apparatus 1 may include both the voltage pulse generating unit 240 and the RF generating unit 400 described above.

[0062] Although the above embodiment has been described as 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, an inductively coupled plasma processing apparatus may be used instead of the capacitively coupled plasma processing apparatus.

[0063] Embodiments of the present disclosure further include the following aspects.

[0064] a substrate support disposed within the plasma processing chamber, the substrate support including: a conductive base; an electrostatic chuck disposed on the conductive base and having a substrate support surface and a ring support surface; an edge ring disposed on the ring support surface to surround a substrate disposed on the substrate support surface; a substrate bias electrode disposed within the electrostatic chuck below the substrate support surface; a ring bias electrode disposed within the electrostatic chuck below the ring support surface; an additional electrode disposed within the electrostatic chuck between the ring support surface and the ring bias electrode, the additional electrode being electrically connected to ground potential via the variable impedance element; and at least one connector electrically connecting the edge ring and the conductive base; and at least one voltage pulse generator electrically connected to the substrate bias electrode and the ring bias electrode and configured to generate a pulsed voltage signal.

[0065] (Supplementary Note 2) The plasma processing apparatus according to Supplementary Note 1, wherein the at least one voltage pulse generating unit is electrically connected to the substrate bias electrode and the ring bias electrode via the conductive base.

[0066] (Supplementary Note 3) The plasma processing apparatus according to Supplementary Note 1 or 2, wherein the at least one voltage pulse generating unit includes: a first voltage pulse generating unit electrically connected to the substrate bias electrode and configured to generate a first pulsed voltage signal; and a second voltage pulse generating unit electrically connected to the ring bias electrode and configured to generate a second pulsed voltage signal.

[0067] (Supplementary Note 4) The plasma processing apparatus according to any one of Supplementary Notes 1 to 3, wherein the substrate support portion includes a substrate chuck electrode, and the substrate chuck electrode is disposed between the substrate bias electrode and the substrate support surface within the electrostatic chuck.

[0068] (Supplementary Note 5) The plasma processing apparatus according to any one of Supplementary Notes 1 to 4, wherein the substrate support includes a ring chuck electrode, and the ring chuck electrode is disposed between the ring support surface and the additional electrode within the electrostatic chuck.

[0069] a substrate support disposed within the plasma processing chamber, the substrate support including: a conductive base; an electrostatic chuck disposed on the conductive base and having a substrate support surface and a ring support surface; an edge ring disposed on the ring support surface to surround a substrate disposed on the substrate support surface; a substrate bias electrode disposed within the electrostatic chuck below the substrate support surface; a ring bias electrode disposed within the electrostatic chuck below the ring support surface; an additional electrode disposed within the electrostatic chuck between the ring support surface and the ring bias electrode, the additional electrode being electrically connected to ground potential via the variable impedance element; and at least one connector electrically connecting the edge ring and the conductive base; and at least one RF generator electrically connected to the substrate bias electrode and the ring bias electrode and configured to generate an RF signal.

[0070] (Supplementary Note 7) The plasma processing apparatus according to Supplementary Note 6, wherein the at least one RF generating unit is electrically connected to the substrate bias electrode and the ring bias electrode via the conductive base.

[0071] (Supplementary Note 8) The plasma processing apparatus according to Supplementary Note 6 or 7, wherein the at least one RF generating unit includes: a first RF generating unit electrically connected to the substrate bias electrode; and a second RF generating unit electrically connected to the ring bias electrode.

[0072] (Supplementary Note 9) The plasma processing apparatus according to any one of Supplementary Notes 6 to 8, wherein the substrate support portion includes a substrate chuck electrode, and the substrate chuck electrode is disposed between the substrate electrode and the substrate support surface within the electrostatic chuck.

[0073] (Supplementary Note 10) The plasma processing apparatus according to any one of Supplementary Notes 6 to 9, wherein the substrate support includes a ring chuck electrode, and the ring chuck electrode is disposed between the ring support surface and the additional electrode within the electrostatic chuck.

[0074] 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.

[0075] 1... plasma processing apparatus, 10... plasma processing chamber, 11... substrate support, 200... edge ring, 201... substrate bias electrode, 202... ring bias electrode, 203... additional electrode, 204... connector, 1110... conductive base, 1111... electrostatic chuck, 240... voltage pulse generating unit, 260... variable impedance element, W... substrate

Claims

a substrate support disposed within the plasma processing chamber, the substrate support including: a conductive base; an electrostatic chuck disposed on the conductive base, the electrostatic chuck having a substrate support surface and a ring support surface; an edge ring disposed on the ring support surface to surround a substrate disposed on the substrate support surface; a substrate bias electrode disposed within the electrostatic chuck below the substrate support surface; a ring bias electrode disposed within the electrostatic chuck below the ring support surface; an additional electrode disposed within the electrostatic chuck between the ring support surface and the ring bias electrode, the additional electrode being electrically connected to a ground potential through the variable impedance element; and at least one connector electrically connecting the edge ring and the conductive base; and at least one voltage pulse generator electrically connected to the substrate bias electrode and the ring bias electrode and configured to generate a pulsed voltage signal.

2. The plasma processing apparatus according to claim 1, wherein the at least one voltage pulse generating unit is electrically connected to the substrate bias electrode and the ring bias electrode via the conductive base.

3. The plasma processing apparatus of claim 1, wherein the at least one voltage pulse generating unit includes: a first voltage pulse generating unit electrically connected to the substrate bias electrode and configured to generate a first pulsed voltage signal; and a second voltage pulse generating unit electrically connected to the ring bias electrode and configured to generate a second pulsed voltage signal.

4. A plasma processing apparatus according to any one of claims 1 to 3, wherein the substrate support includes a substrate chuck electrode, the substrate chuck electrode being disposed within the electrostatic chuck between the substrate bias electrode and the substrate support surface.

5. The plasma processing apparatus of claim 4, wherein the substrate support includes a ring chuck electrode, the ring chuck electrode being disposed within the electrostatic chuck between the ring support surface and the additional electrode.

6. A plasma processing apparatus comprising: a plasma processing chamber; a variable impedance element; a substrate support disposed within the plasma processing chamber, the substrate support including: a conductive base; an electrostatic chuck disposed on the conductive base, the electrostatic chuck having a substrate support surface and a ring support surface; an edge ring disposed on the ring support surface to surround a substrate disposed on the substrate support surface; a substrate bias electrode disposed within the electrostatic chuck below the substrate support surface; a ring bias electrode disposed within the electrostatic chuck below the ring support surface; an additional electrode disposed within the electrostatic chuck between the ring support surface and the ring bias electrode, the additional electrode being electrically connected to a ground potential via the variable impedance element; and at least one connector electrically connecting the edge ring and the conductive base; and at least one RF generator electrically connected to the substrate bias electrode and the ring bias electrode and configured to generate an RF signal.

7. The plasma processing apparatus according to claim 6, wherein the at least one RF generating unit is electrically connected to the substrate bias electrode and the ring bias electrode via the conductive base.

8. The plasma processing apparatus according to claim 6, wherein the at least one RF generating unit includes: a first RF generating unit electrically connected to the substrate bias electrode; and a second RF generating unit electrically connected to the ring bias electrode.

9. A plasma processing apparatus according to any one of claims 6 to 8, wherein the substrate support includes a substrate chuck electrode, the substrate chuck electrode being disposed within the electrostatic chuck between the substrate electrode and the substrate support surface.

10. The plasma processing apparatus of claim 9, wherein the substrate support includes a ring chuck electrode, the ring chuck electrode being disposed within the electrostatic chuck between the ring support surface and the additional electrode.