JP7825538B2 - Plasma processing equipment - Google Patents

Description

This disclosure relates to a plasma processing apparatus.

Patent Document 1 discloses a substrate support table having an annular member mounting surface on which an annular member is placed, and three or more lifters configured to protrude from the annular member mounting surface. According to the description in Patent Document 1, recesses formed from upwardly recessed surfaces are provided on the bottom surface of the annular member at positions corresponding to each of the lifters, and in a plan view, the recesses are larger than the transport accuracy of the annular member above the annular member mounting surface and larger than the upper ends of the lifters. Furthermore, the upper ends of the lifters are formed hemispherically, and the concave surfaces are formed with a smaller curvature than the concave surfaces forming the hemispheres at the upper ends of the lifters.

Japanese Patent Application Laid-Open No. 2021-141313

The technology disclosed herein provides a plasma processing apparatus that allows for proper positioning of the ring assembly relative to the substrate support.

One aspect of the present disclosure is a plasma processing apparatus for processing a substrate, the apparatus comprising: a plasma processing chamber; a substrate support disposed within the plasma processing chamber and having a substrate support surface and a ring support surface; an insulating ring disposed on the ring support surface and having at least three through holes, each of the at least three through holes having an upper hole portion and a lower hole portion, the upper hole portion having a first width in a radial direction of the insulating ring and a second width in a circumferential direction of the insulating ring, the second width being smaller than the first width; and the lower hole portion having a flared shape widening downward in a side view; and a conductive ring supported by the insulating ring and having at least three grooves on its lower surface corresponding to the at least three through holes, each of the at least three grooves being oriented radially of the conductive ring. the conductive ring having a third width in a circumferential direction of the conductive ring and a fourth width in a circumferential direction of the conductive ring, the fourth width being smaller than the third width; at least three lift pins arranged below the ring support surface and corresponding to each of the at least three grooves, each of the at least three lift pins having an upper support portion and a lower support portion, the upper support portion configured to support the conductive ring from below by contacting a bottom surface of the groove in the conductive ring through the through hole in the insulating ring, and the lower support portion configured to support the insulating ring from below by contacting an inclined surface of the insulating ring that defines the lower hole portion; and at least one actuator configured to move the at least three lift pins in a vertical direction.

The present disclosure provides a plasma processing apparatus that allows for appropriate positioning of the ring assembly relative to the substrate support.

FIG. 1 is an explanatory diagram showing an outline of the configuration of a plasma processing system. 1 is a vertical cross-sectional view showing an outline of the configuration of a plasma processing apparatus according to an embodiment; FIG. 3 is a partially enlarged view of FIG. 2. FIG. 2 is an explanatory diagram showing an outline of the configuration of an insulating ring. FIG. 2 is an explanatory diagram showing an outline of the configuration of an insulating ring. FIG. 2 is an explanatory diagram showing an outline of the configuration of an inner edge ring. FIG. 2 is an explanatory diagram showing an outline of the configuration of an inner edge ring. 10A and 10B are explanatory diagrams showing another example of forming grooves in the inner edge ring. 10A and 10B are explanatory diagrams showing another example of forming grooves in the inner edge ring. 10A and 10B are explanatory views showing another example of forming a through hole in an insulating ring. 10A and 10B are diagrams illustrating a ring assembly replacement process. 10A and 10B are diagrams illustrating a ring assembly replacement process. 10A and 10B are diagrams illustrating a ring assembly replacement process. 10A and 10B are diagrams illustrating a ring assembly replacement process. 10A and 10B are diagrams illustrating a ring assembly replacement process. FIG. 10 is a diagram illustrating another example of the configuration of the inner edge ring. FIG. 10 is a diagram illustrating another example of the configuration of the inner edge ring. FIG. 10 is a diagram illustrating another example of the configuration of the inner edge ring. 10A and 10B are explanatory diagrams showing another example of forming grooves in the inner edge ring. 10A and 10B are explanatory diagrams showing another example of forming grooves in the inner edge ring. 10A and 10B are explanatory diagrams showing another example of forming grooves in the inner edge ring. 10A and 10B are explanatory diagrams showing another example of forming grooves in the inner edge ring. 10A and 10B are explanatory diagrams showing another example of forming grooves in the inner edge ring. 10A and 10B are explanatory diagrams showing another example of forming grooves in the inner edge ring. 10A and 10B are explanatory diagrams showing another example of forming grooves in the inner edge ring.

In the manufacturing process of semiconductor devices, etc., plasma processing such as etching is performed on semiconductor substrates (hereinafter simply referred to as "substrates") using plasma. Plasma processing is performed with the substrate placed on a substrate support placed inside a processing chamber that can be depressurized.

The substrate support table also includes multiple annular members arranged to surround the periphery of the substrate on the substrate support member in order to obtain good and uniform processing results at the center and periphery of the substrate during plasma processing. The multiple annular members include an edge ring arranged adjacent to the substrate on the substrate support member, and a cover ring arranged to cover the outer surface of the edge ring. These annular members wear out when exposed to plasma and therefore require periodic replacement. The annular members are replaced, for example, using a lifter that raises and lowers the annular members while supporting them, and a transport mechanism that transports the annular members.

However, when replacing annular members using these lifters or transport mechanisms, it may not be possible to properly position the annular members at the desired position on the substrate support part due to factors such as the transport accuracy of the transport mechanism. Furthermore, in recent years, when realizing the transport function of annular members, there has been a greater demand for improved placement accuracy of the annular members on the substrate support part compared to the transport accuracy of the transport mechanism.

In the plasma processing apparatus described in Patent Document 1, a groove larger than the transport accuracy of the transport mechanism is formed in the bottom surface of the edge ring, and a through-hole larger than the transport accuracy of the transport mechanism is formed in the cover ring, thereby improving the positioning accuracy of the annular member. However, when replacing an annular member using the plasma processing apparatus described in Patent Document 1, if a relative misalignment occurs between the lifter and the groove (through-hole) due to mechanical differences (e.g., processing tolerances) or thermal expansion of the annular member, for example, there is a risk that the positioning accuracy of the annular member will deteriorate or that the lifter or annular member will be damaged.

The technology disclosed herein has been developed in light of the above circumstances, and provides a plasma processing apparatus that allows for appropriate positioning of a ring assembly relative to a substrate support. Below, a plasma processing system equipped with a substrate processing apparatus according to this embodiment will be described with reference to the drawings. Note that in this specification and drawings, elements that have substantially the same functional configuration are designated by the same reference numerals, and redundant description will be omitted.

<Plasma processing system>
In one embodiment, the plasma processing system includes a plasma processing apparatus 1, a transfer apparatus 2, and a control unit 3, as shown in FIG. 1 . 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.

The plasma generation unit 12 is configured to generate plasma from at least one processing gas supplied into the plasma processing space. The plasma formed in the plasma processing space may be capacitively coupled plasma (CCP), inductively coupled plasma (ICP), electron-cyclotron-resonance plasma (ECR plasma), helicon wave plasma (HWP), or surface wave plasma (SWP), among others. 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.

The transfer device 2 includes a transfer arm 2a that holds and transfers the substrate W and a ring assembly 120 (described later). A wafer is an example of a substrate W. The transfer device 2 is configured to be able to transfer the substrate W and ring assembly 120 between, for example, the outside of the plasma processing apparatus 1 and a substrate support part 11 arranged inside the plasma processing apparatus 1.

The control unit 3 processes computer-executable instructions that cause the plasma processing apparatus 1 and the transport device 2 to perform the various processes described in this disclosure. The control unit 3 may be configured to control each element of the plasma processing apparatus 1 and the transport device 2 to perform the various processes described herein. In one embodiment, part or all of the control unit 3 may be included in the plasma processing apparatus 1. The control unit 3 may include a processing unit 3a1, a memory unit 3a2, and a communication interface 3a3. The control unit 3 is realized, for example, by a computer 3a. The processing unit 3a1 may be configured to perform various control operations by reading a program from the memory unit 3a2 and executing the read program. This program may be stored in the memory unit 3a2 in advance or may be acquired via a medium when needed. The acquired program is stored in the memory unit 3a2 and read from the memory unit 3a2 by the processing unit 3a1 for execution. The medium may be various storage media readable by the computer 3a, or may be a communication line connected to the communication interface 3a3. The processing unit 3a1 may be a CPU (Central Processing Unit). The storage unit 3a2 may include RAM (Random Access Memory), ROM (Read Only Memory), HDD (Hard Disk Drive), SSD (Solid State Drive), or a combination thereof. The communication interface 3a3 may communicate with the plasma processing apparatus 1 via a communication line such as a LAN (Local Area Network). The storage medium may be temporary or non-temporary.

<Plasma treatment device>
Next, a configuration example of a capacitively coupled plasma processing apparatus 1 will be described as an example of the above-mentioned plasma processing apparatus 1. Fig. 2 is a vertical cross-sectional view showing an outline of the configuration of the plasma processing apparatus 1. Fig. 3 is a partially enlarged view showing a part of the configuration of the substrate support part 11 shown in Fig. 2.

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, the 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.

The substrate support 11 includes a main body 110, a ring assembly 120, and a lifter 130. The main body 110 has a central region 110a for supporting a substrate W and an annular region 110b for supporting the ring assembly 120. The annular region 110b of the main body 110 surrounds the central region 110a of the main body 110 in a plan view. The substrate W is disposed on the central region 110a of the main body 110, and the ring assembly 120 is disposed on the annular region 110b of the main body 110 so as to surround the substrate W on the central region 110a of the main body 110. Therefore, the central region 110a is also referred to as a substrate support surface for supporting the substrate W, and the annular region 110b is also referred to as a ring support surface for supporting the ring assembly 120.

As shown in FIG. 3, in one embodiment, the main body 110 includes a base 111, an electrostatic chuck 112, a support 113, and an insulator 114.

The base 111 includes a conductive member. The conductive member of the base 111 may function as a lower electrode. The electrostatic chuck 112 is disposed on the base 111. The electrostatic chuck 112 includes a ceramic member 112a and an electrostatic electrode 112b disposed within the ceramic member 112a. The ceramic member 112a has a central region 110a. In one embodiment, the ceramic member 112a and the support 113 have an annular region 110b. Note that instead of an annular insulating member such as the support 113, another member surrounding the electrostatic chuck 112, such as an annular electrostatic chuck, may have the annular region 110b. The ring assembly 120 may be disposed on the annular electrostatic chuck or the annular insulating member, or may be disposed on both the electrostatic chuck 112 and the annular insulating member as shown. Alternatively, the annular electrostatic chuck and annular insulating member may be omitted, and the ring assembly 120 may be disposed only on the electrostatic chuck 112.

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 112a. 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 111 and the at least one RF/DC electrode may function as multiple lower electrodes. Furthermore, the electrostatic electrode 112b may function as a lower electrode. Therefore, the substrate support 11 includes at least one lower electrode.

The support 113 is a member formed in a ring shape in a plan view using an insulating material such as quartz, and supports the base 111 and the electrostatic chuck 112. In one embodiment, the ring assembly 120 is mounted on the support 113 as described above. The support 113 also has multiple through-holes 113a (three in this embodiment) that penetrate through the thickness. As shown in FIG. 3, lift pins 131 of the lifter 130, which will be described later, are inserted into the through-holes 113a.

The insulator 114 is a cylindrical member made of ceramic or the like, and supports the support 113. The insulator 114 is formed, for example, to have an outer diameter equal to the outer diameter of the support 113, and supports the peripheral edge of the support 113.

The ring assembly 120 as an annular member includes multiple annular members. As shown in FIG. 3 as an example, the ring assembly 120 includes an insulating ring 121, an outer edge ring 122, and an inner edge ring 123 as the multiple annular members. The outer edge ring 122 and the inner edge ring 123 are formed of, for example, silicon, silicon carbide, or quartz. The insulating ring 121 is supported by a support 113 that constitutes the annular region 11b (ring support surface). The inner edge ring 123 is supported by the electrostatic chuck 112 and the insulating ring 121 that constitute the annular region 110b (ring support surface). That is, the insulating ring 121 and the inner edge ring 123 are stacked in this order and supported by the support 113 that constitutes the annular region 11b (ring support surface). The ring assembly 120 is lifted up from the annular region 110b (ring support surface) by the operation of a lifter 130, thereby enabling it to be transferred to and from a transfer device 2 disposed outside the plasma processing apparatus 1.
The inner edge ring 123 may be a "conductive ring" according to the technology of the present disclosure. The outer edge ring 122 may be an "additional conductive ring" according to the technology of the present disclosure. In other words, the ring assembly 120 as an annular member includes the insulating ring 121, the additional conductive ring 122, and the conductive ring 123 as multiple annular members.

The outer edge ring 122 is formed to be larger in the thickness direction than the insulating ring 121 and is positioned to surround the inner edge ring 123 and insulating ring 121, with the inner portion of the outer edge ring 122 overlapping the outer portion of the insulating ring 121 in the vertical direction. In other words, the upper surface of the insulating ring 121 forms a support surface for the outer edge ring 122 and inner edge ring 123.

The configuration of the ring assembly 120 is not limited to the example shown in the figure; for example, the insulating ring 121 and the outer edge ring 122 may be integrally configured. In this case, the insulating ring 121 and the outer edge ring 122 may be configured from the same material; that is, the outer edge ring 122 may function as part of the insulating ring, and the insulating ring 121 may function as part of an additional conductive ring.

Furthermore, as shown in Figures 4A and 4B, the insulating ring 121 has multiple through-holes 121a (three in this embodiment) formed therethrough in the thickness direction. The through-holes 121a are formed at positions corresponding to the through-holes 113a formed in the support 113, and as shown in Figure 3, the upper support portions 131a of the lift pins 131 described below are inserted through the through-holes 121a.

The three through holes 121a have an upper hole portion 121a1 and a lower hole portion 121a2.
The upper hole portion 121a1 of the through hole 121a has a substantially rectangular shape in which a first width W1 extending in a radial direction R1 of the insulating ring 121 is larger than a second width W2 extending in a circumferential direction C1 of the insulating ring 121 that is perpendicular to the radial direction R1. The first width W1 is larger than at least the diameter (a fifth width W5 described later) of an upper support portion 131a of a lift pin 131 described later. The second width W2 is larger than the diameter (fifth width W5) of the upper support portion 131a and smaller than the diameter (a sixth width W6 described later) of a lower support portion 131b of the lift pin 131 described later.
The lower hole portion 121a2 of the insulating ring 121 has a flared shape (inclined surface 1211a) in which the first width W1 and second width W2 of the upper hole portion 121a1 widen downward (toward the bottom surface of the insulating ring 121). It is desirable that the lower end of the inclined surface 1211a of the lower hole portion 121a2 be formed to be larger than at least the transport accuracy of the ring assembly 120 by the transport device 2.
In the insulating ring 121 of this embodiment, this allows the upper support portion 131a of the lift pin 131 to be inserted into the upper hole portion 121a1, and the lower support portion 131b of the lift pin 131 to come into two-point contact with the inclined surface 1211a of the lower hole portion 121a2 on the circumferential direction C1 side (second width W2 side).

As described above, in the upper hole portion 121a1, the first width W1 extending in the radial direction R1 is formed to be larger than the second width W2 extending in the circumferential direction C1, but it is desirable that the first width W1 and the second width W2 be as similar in size as possible. In other words, it is desirable that the upper hole portion 121a1 have a substantially square shape in a plan view.

The inner edge ring 123, which serves as a conductive ring and is sometimes called a focus ring, improves the in-plane uniformity of plasma processing on the substrate W. The outer edge ring 122, which serves as an additional conductive ring, effectively expands the area of the conductive portion (inner edge ring 123) in a planar view on the substrate support 11. As described above, the inner edge ring 123 and the outer edge ring 122 can be formed from silicon, silicon carbide, quartz, or the like.

As shown in Figures 5A and 5B, multiple grooves 123a (three in this embodiment) are formed in the bottom surface of the inner edge ring 123. The grooves 123a are formed at positions corresponding to the through holes 121a formed in the insulating ring 121, and the tips of the upper support portions 131a of the lift pins 131 inserted into the through holes 121a contact the bottom surfaces 123a1.

5B , each of the three grooves 123a has a generally elongated hole shape in which a third width W3 extending in a radial direction R2 of the inner edge ring 123 at the bottom surface 123a1 is larger than a fourth width W4 extending in a circumferential direction C2 of the inner edge ring 123 perpendicular to the radial direction R2. The third width W3 is larger than a diameter (fifth width W5) of the upper support portion 131a. The fourth width W4 is generally the same as a diameter (fifth width W5) of the upper support portion 131a of a lift pin 131, which will be described later.
Furthermore, the bottom surfaces 123a1 of the three grooves 123a have a shape that fits with the shape of the tip end of the upper support portion 131a of the lift pin 131, particularly in the extension direction of the fourth width W4. Specifically, in this embodiment, as will be described later, the upper support portion 131a has a hemispherical shape 131a1 with a protruding tip end, and the bottom surfaces 123a1 of the grooves 123a are formed in a concave shape having substantially the same curvature as the hemispherical shape 131a1 (hereinafter, the bottom surface 123a1 having a curved shape may be referred to as a "curved bottom surface 123a1'").
The flared side surfaces 123a2 of the three grooves 123a are formed with inclined portions so that the third width W3 and the fourth width W4 of the bottom surface 123a1 widen downward (toward the bottom surface of the inner edge ring 123). It is desirable that the lower ends of the inclined portions of the grooves 123a be formed to be at least larger than the transport accuracy of the inner edge ring 123 by the transport device 2.
In the inner edge ring 123 according to this embodiment, this causes the upper support portions 131a of the lift pins 131 to be in line contact with the bottom surface 123a1 in the circumferential direction of the inner edge ring 123 (the direction of the fourth width W4).

The depth of groove 123a is, for example, 0.4 mm or more and 1.0 mm or less.

In one embodiment, the lifter 130 includes multiple lift pins 131, three in this embodiment, corresponding to the through holes 121a of the insulating ring 121 and the grooves 123a of the inner edge ring 123, and at least one actuator 132. The lift pin 131 also includes multiple cylindrical support portions with different diameters. As shown as an example in FIG. 3, the lift pin 131 includes an upper support portion 131a and a lower support portion 131b. The upper support portion 131a and the lower support portion 131b may be integrally formed.

The upper support portion 131a has a fifth width W5 that is smaller than at least the first width W1 and second width W2 of the through hole 121a formed in the insulating ring 121. The fifth width W5 is approximately the same size as the fourth width W4 of the groove 123a formed in the inner edge ring 123. The upper support portion 131a is axially connected to the upper surface of the lower support portion 131b (described below) and moves vertically (axially) together with the lower support portion 131b by operation of the actuator 132. The upper support portion 131a is configured to be able to freely protrude and retract from the upper surface of the insulating ring 121 via the through hole 121a, thereby supporting and moving (lifting up) the lower surface of the inner edge ring 123, which is supported on the upper surface of the insulating ring 121; more specifically, the bottom surface 123a1 of the groove 123a formed in the inner edge ring 123.

The tip of the upper support portion 131a is formed in a hemispherical shape 131a1 that gradually tapers upward (see Figure 5B). This hemispherical shape 131a1 has approximately the same curvature as the concave surface of the curved bottom surface 123a1' of the groove 123a formed in the inner edge ring 123. This allows the tip of the upper support portion 131a to come into line contact with the groove 123a formed in the inner edge ring 123.

The lower support portion 131b has a diameter (sixth width W6 in Figure 3) larger than at least the second width W2 of the through hole 121a formed in the insulating ring 121. That is, the lower support portion 131b has a step on its upper surface that protrudes radially outward from the outer periphery of the upper support portion 131a. The lower support portion 131b is configured to be able to support the inclined surface 1211a formed on the lower hole portion 121a2 of the through hole 121a with the step, thereby supporting the lower surface of the insulating ring 121 and moving it vertically (lifting it up). At the same time, the outer edge ring 122 held on the insulating ring 121 also moves vertically (lifts up) at the same time.

The actuator 132 moves the lift pins 131 in the vertical direction (axial direction), raising and lowering the ring assembly 120 (insulating ring 121, outer edge ring 122, and inner edge ring 123) above the annular region 110b (ring support surface). This allows the ring assembly 120 to be transferred between the substrate support 11 and the transfer arm 2a of the transfer device 2. Examples of actuators include an electric actuator, an air cylinder, a motor, etc.

The number of actuators 132 arranged on the lifter 130 is not particularly limited. That is, for example, multiple lift pins 131 may be moved vertically as a unit by a single actuator 132. Alternatively, for example, multiple actuators 132 may be arranged corresponding to each lift pin 131, and each lift pin 131 may be moved vertically independently.

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

Returning to the description of FIG.
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 from the gas supply unit 20 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.

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.

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 causes a plasma to be formed 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 at least one lower electrode, a bias potential is generated on the substrate W, and ion components in the formed plasma can be attracted to the substrate W.

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.

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. Also, in various embodiments, at least one of the source RF signal and the bias RF signal may be pulsed.

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

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 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 generators 32a and 32b may be provided in addition to the RF power supply 31, or the first DC generator 32a may be provided instead of the second RF generator 31b.

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

Various exemplary embodiments have been described above, but the present invention is not limited to the exemplary embodiments described above, and various additions, omissions, substitutions, and modifications may be made. Furthermore, elements from different embodiments can be combined to form other embodiments.

For example, in the above embodiment, the tip of the upper support portion 131a of the lift pin 131 is formed in a hemispherical shape 131a1 as shown in Fig. 3, but the tip of the upper support portion 131a may have a substantially flat surface 131a2 as shown in Fig. 6A. In this case, in order to bring the tip of the upper support portion 131a into line contact with the bottom surface of the groove 123a, it is desirable that the bottom surface of the groove 123a also have a flat bottom surface 123a1" that engages with the tip of the upper support portion 131a instead of the curved bottom surface 123a1' described above.
Also in this case, as shown in FIG. 6B, each of the at least three grooves 123a of the conductive ring 123 may be defined by a flat bottom surface 123a1'', a vertical side surface 123a3 extending downward from the flat bottom surface 123a1'', and a flared side surface 123a2 widening downward from the vertical side surface 123a3.

In the above embodiment, the through hole 121a formed in the insulating ring 121 is formed to have a substantially rectangular shape, preferably a substantially square shape. However, as shown in FIG. 6C, the through hole 121a may be formed to have a substantially elongated hole shape with large rounded corners. In this case, it is desirable that the substantially elongated through hole 121a has a first width W1 extending in the radial direction R1 of the insulating ring 121 that is larger than a second width W2 extending in the circumferential direction C1; in other words, it is desirable that the through hole 121a has a elongated hole shape with its longitudinal direction in the radial direction R1 of the insulating ring 121.

<Effects, etc.>
The plasma processing system according to one embodiment is configured as described above. Specifically, the plasma processing system according to one embodiment includes a plasma processing chamber 10, a substrate support 11, an insulating ring 121, a conductive ring 123, at least three lift pins 131, and at least one actuator 132. The substrate support 11 is disposed in the plasma processing chamber 10 and has a substrate support surface 110a and a ring support surface 110b. The insulating ring 121 is disposed on the ring support surface 110b and has at least three through holes 121a. Each of the at least three through holes 121a has an upper hole portion 121a1 and a lower hole portion 121a2. The upper hole portion 121a1 has a first width W1 in a radial direction R1 of the insulating ring 121 and a second width W2 in a circumferential direction C1 of the insulating ring 121. The second width W2 is smaller than the first width W1, and the lower hole portion 121a2 has a flared shape widening downward when viewed from the side. The conductive ring 123 is supported by the insulating ring 121 and has at least three grooves 123a on its lower surface corresponding to the at least three through holes 121a. Each of the at least three grooves 123a has a third width W3 in the radial direction R2 of the conductive ring 123 and a fourth width W4 in the circumferential direction C2 of the conductive ring 123. The fourth width W4 is smaller than the third width W3. The at least three lift pins 131 are disposed below the ring support surface 110b and correspond to the at least three grooves 123a. Each of the at least three lift pins 131 has an upper support portion 131a and a lower support portion 131b. The upper support portion 131a is configured to support the conductive ring 123 from below by contacting the bottom surface 123a1 of the groove 123a of the conductive ring 123 through the through-hole 121a of the insulating ring 121. The lower support portion 131b is configured to support the insulating ring 121 from below by contacting the inclined surface 1211a of the insulating ring 121 that defines the lower hole portion 121a2. At least one actuator 132 is configured to move at least three lift pins 131 in the vertical direction. The lower support portion 131b of the lift pin 131 is configured to contact the inclined surface 1211a at two points in the radial direction R1 of the insulating ring 121 without contacting the inclined surface 1211a in the circumferential direction C1 of the insulating ring 121.

In one embodiment, each of the at least three through holes 121a in the insulating ring 121 has a rectangular shape when viewed from above. In one embodiment, the upper support portion 131a has a cylindrical shape with a first diameter W5 smaller than the second width W2, and the lower support portion 131b has a cylindrical shape with a second diameter W6 larger than the second width W2. In one embodiment, the tip of the upper support portion 131a of the lift pin 131 has a hemispherical shape 131a1. In one embodiment, the tip of the upper support portion 131a of the lift pin 131 has a flat surface 131a2. In one embodiment, each of the at least three grooves 123a in the conductive ring 123 is defined by a flat bottom surface 123a1'', a vertical side surface 123a3 extending downward from the flat bottom surface 123a1'', and a flared side surface 123a2 diverging downward from the vertical side surface 123a3. In one embodiment, each of the at least three grooves 123a in the conductive ring 123 is defined by a curved bottom surface 123a1'. In one embodiment, each of the at least three grooves 123a in the conductive ring 123 is defined by a flat bottom surface 123a1" and a flared side surface 123a2 that flares downwardly from the flat bottom surface 123a1". In one embodiment, the plasma processing system 1 further includes an additional conductive ring 122 disposed around the conductive ring 123 and the insulating ring 121. At least a portion of the additional conductive ring 122 vertically overlaps an outer portion of the insulating ring 121.

Also, according to one embodiment, a plasma processing system 1 includes a plasma processing chamber 10, a substrate support 11, a first annular member 121, a second annular member 123, at least three lift pins 131, and at least one actuator 132. The substrate support 11 is disposed within the plasma processing chamber 10 and has a substrate support surface 110a and a ring support surface 110b. The first annular member 121 is disposed on the ring support surface 110b and has at least three through holes 121a. Each of the at least three through holes 121a has an upper hole portion 121a1 and a lower hole portion 121a2. The upper hole portion 121a1 has a first width W1 in a first direction R1 and a second width W2 in a second direction C1 perpendicular to the first direction R1. The second width W2 is smaller than the first width W1. The lower hole portion 121a2 has a flared shape 1211a widening downward when viewed from the side. The second annular member 123 is supported by the first annular member 121 and has at least three grooves 123a on its lower surface corresponding to the at least three through holes 121a. Each of the at least three grooves 123a has a third width W3 in the third direction R2 and a fourth width W4 in a fourth direction C2 perpendicular to the third direction R2. The fourth width W4 is smaller than the third width W3. At least three lift pins 131 are disposed below the ring support surface 110b and correspond to the at least three grooves 123a. Each of the at least three lift pins 131 has an upper support portion 131a and a lower support portion 131b. The upper support portion 131a is configured to support the second annular member 123 from below by contacting the bottom surface 123a1 of the groove 123a of the second annular member 123 through the through hole 121a of the first annular member 121. The lower support portion 131b is configured to support the first annular member 121 from below by contacting the inclined surface 1211a of the first annular member 121 that defines the lower hole portion 121a2. At least one actuator 132 is configured to move the at least three lift pins 131 vertically.

In the plasma processing system, a substrate W is transported into the plasma processing apparatus 1 using a transport device 2, and after the desired plasma processing such as etching is performed on the transported substrate W, the substrate W is transported out of the plasma processing apparatus 1 using the transport device 2.
In this embodiment, the inner edge ring 123 and the outer edge ring 122 are made of a conductive material. Therefore, during plasma processing in the plasma processing system, a sheath is formed above the ring assembly 120, more specifically, above the inner edge ring 123 as a conductive ring and the outer edge ring 122 as an additional conductive ring. This allows for good and uniform plasma processing results to be obtained at the center and peripheral edge of the substrate W held on the substrate support 11.

As described above, in recent plasma processing systems, there is a demand for improved accuracy in placing the ring assembly 120 on the substrate support 11 .
Patent document 1 discloses that in order to improve the installation accuracy of the annular member, the grooves formed in the edge ring and the through holes formed in the cover ring are formed to be larger than the transport accuracy of the annular member by the transport mechanism.However, in this case, there is a risk that the positioning accuracy of the annular member will deteriorate if a misalignment occurs between the lifter and the groove (through hole) due to, for example, mechanical differences in the annular member (e.g., processing tolerances) or thermal expansion.

In this regard, according to the plasma processing apparatus 1 relating to the technology of the present disclosure, a through hole 121a is formed in the insulating ring 121, which corresponds to the cover ring, in an approximately rectangular shape with a first width W1 larger than the second width W2, and a groove 123a is formed in the inner edge ring 123 in an approximately elongated hole shape with a third width W3 larger than the fourth width W4.
As a result, even if a misalignment occurs between the positions of the lift pins 131 and the through holes 121a (grooves 123a) due to the effects of the above-mentioned processing tolerances, etc., the insulating ring 121 can slide about the lift pins 131 as an axis, i.e., is free to move in the longitudinal direction of the through holes 121a (grooves 123a), so the insulating ring 121 can be appropriately guided to the desired position. At this time, the outer edge ring 122 as an additional conductive ring is held on the upper surface of the insulating ring 121, so the position of the outer edge ring 122 is also corrected at the same time.

Also, at this time, as described above, the lower support portion 131b of the lift pin 131 makes contact with the inclined portion of the lower hole portion 121a2 of the through hole 121a at two points. Therefore, compared to when the lower support portion 131b and the inclined portion of the lower hole portion 121a2 make contact at three or more points in the circumferential direction, or when they make line contact or surface contact, the insulating ring 121 slides more easily, allowing for more appropriate correction of misalignment of the insulating ring 121 (ring assembly 120).

At this time, the upper support portion 131a of the lift pin 131 is in line contact with the bottom surface 123a1 of the groove 123a, as described above.
When the upper support portion 131a and the bottom surface 123a1 of the groove 123a contact each other at only one or two points, the upper support portion 131a and the bottom surface 123a1 slide relatively easily, making it easy to correct the positional misalignment of the inner edge ring 123. However, because they slide easily, the position of the inner edge ring 123 is more likely to shift when the lift pin 131 moves vertically.
On the other hand, when the upper support portion 131a and the bottom surface 123a1 of the groove 123a are in surface contact, relative sliding between the bottom surface 123a1 and the upper support portion 131a can be suppressed, but at the same time, since the sliding is suppressed, it becomes difficult to correct the positional misalignment of the inner edge ring 123.
In this regard, in the above embodiment, the upper support portion 131a of the lift pin 131 is in line contact with the bottom surface 123a1 of the groove 123a, so that the bottom surface 123a1 can be slid against the upper support portion 131a to appropriately correct the positional misalignment of the inner edge ring 123, and the positional misalignment of the inner edge ring 123 when the lift pin 131 moves vertically can also be appropriately suppressed.

Furthermore, when the insulating ring 121 is formed with a through hole 121a having an approximately rectangular shape in which the first width W1 is larger than the second width W2, the insulating ring 121 slides in the longitudinal direction of the through hole 121a as described above, which may cause the insulating ring 121 to shift position when the lift pin 131 moves vertically.
In view of this, it is desirable to form the through-hole 121a in a substantially square shape as described above in order to suppress misalignment of the insulating ring 121 (improving the placement accuracy of the insulating ring 121). In addition, in this case, it is desirable to set the longitudinal width of the through-hole 121a (second width W2) to a size that allows the lower support portion 131b of the lift pin 131 to make two-point contact with the inclined portion of the through-hole 121a.
This makes it possible to correct the positional misalignment of the insulating ring 121 by bringing at least the lower support portion 131b and the inclined portion into contact at two points, and also reduces the free width of the lift pin 131 in the longitudinal direction of the through hole 121a, thereby suppressing the positional misalignment of the insulating ring 121 when the lift pin 131 moves vertically.

<How to replace the ring assembly>
Next, the replacement process of the ring assembly 120 configured as above will be described with reference to the drawings. Note that the following process is performed under the control of the control unit 3, for example.

(Step St1: Transfer and Carry-Out of Inner Edge Ring 123)
First, the worn inner edge ring 123 to be replaced is transferred from the substrate support part 11 to the transfer device 2 .

Specifically, first, the lifter 130 is raised, and as shown in FIG. 7, the inner edge ring 123 is transferred from the top surface of the insulating ring 121 to the upper support portion 131a of the lifter 130, which passes through the through-hole 113a of the support 113 and the through-hole 121a of the insulating ring 121. The lifter 130 is raised to a level that prevents the insulating ring 121 from being transferred to the lower support portion 131b, and until the tip of the upper support portion 131a reaches the desired height H1. The desired height H1 here is the height of the upper support portion 131a of the lifter 130, relative to the top surface of the outer edge ring 122 held by the insulating ring 121 placed on the support 113. Furthermore, the desired height H1 is a height at which the transfer arm 2a does not interfere with the outer edge ring 122, inner edge ring 123, etc. when the transfer arm 2a is inserted or removed between the outer edge ring 122 on the insulating ring 121 placed on the support 113 and the inner edge ring 123 supported by the upper support portion 131a.

The inner edge ring 123 is then removed from the plasma processing chamber 10 of the plasma processing apparatus 1.

Specifically, the transfer arm 2a is inserted into the reduced-pressure plasma processing chamber 10 through a transfer port (not shown). The transfer arm 2a is then moved between the outer edge ring 122 on the insulating ring 121 placed on the support 113 and the inner edge ring 123 supported on the upper support portion 131a of the lifter 130.

The lifter 130 is then lowered, and the inner edge ring 123 is transferred from the upper support portion 131a of the lifter 130 to the transfer arm 2a. The transfer arm 2a is then removed from the plasma processing chamber 10, and the inner edge ring 123 is removed from the plasma processing apparatus 1. The removed inner edge ring 123 is then loaded into a storage module (not shown), for example.

(Step St2: Transfer and Carry Out the Insulating Ring 121 and the Outer Edge Ring 122)
After the inner edge ring 123 is carried out of the plasma processing apparatus 1 , the worn insulating ring 121 and the outer edge ring 122 to be replaced are then transferred from the substrate support part 11 to the transfer device 2 .

Specifically, first, the lifter 130 is raised, and as shown in FIG. 8 , the insulating ring 121 is transferred from the upper surface of the annular region 110b (ring support surface) of the substrate support 11 to the lower support portion 131b of the lifter 130, which passes through the through-hole 113a of the support 113. At this time, because the outer edge ring 122 is held on the insulating ring 121, the outer edge ring 122 is also transferred to the lower support portion 131b via the insulating ring 121. The lifter 130 is raised until the step portion of the lower support portion 131b reaches the desired height H2. The desired height H2 here is the height of the lower support portion 131b of the lifter 130 relative to the upper surface of the substrate support 11 (more specifically, the upper surface of the electrostatic chuck 112). Furthermore, the desired height H2 is a height at which the transfer arm 2a does not interfere with the insulating ring 121, electrostatic chuck 112, etc. when the transfer arm 2a is inserted or removed between the electrostatic chuck 112 and the insulating ring 121 supported by the lower support portion 131b.

The insulating ring 121 and outer edge ring 122 are then removed from the plasma processing chamber 10 of the plasma processing apparatus 1.

Specifically, the transfer arm 2a is inserted into the depressurized plasma processing chamber 10 through a loading/unloading port (not shown). The transfer arm 2a is then moved between the electrostatic chuck 112 and the insulating ring 121 supported by the lower support portion 131b of the lifter 130.

The lifter 130 is then lowered, and the insulating ring 121 and outer edge ring 122 are transferred from the lower support portion 131b of the lifter 130 to the transfer arm 2a. The transfer arm 2a is then removed from the plasma processing chamber 10, and the insulating ring 121 and outer edge ring 122 are removed from the plasma processing apparatus 1. The removed insulating ring 121 and outer edge ring 122 are then transferred into, for example, a storage module (not shown).

(Step St3: Carrying in and placing the ring assembly 120)
Once the inner edge ring 123, insulating ring 121 and outer edge ring 122 are removed from the plasma processing apparatus 1, a new ring assembly 120 (insulating ring 121, outer edge ring 122 and inner edge ring 123) to be replaced is then loaded into the plasma processing apparatus 1.

Specifically, the transfer arm 2a of the transfer device 2 holding the new ring assembly 120 including the insulating ring 121 and the outer edge ring 122 and inner edge ring 123 held on the insulating ring 121 is inserted into the plasma processing chamber 10 through a loading/unloading port (not shown). At this time, the plasma processing chamber 10 may be depressurized. Then, as shown in FIG. 9 , the new ring assembly 120 is transferred by the transfer arm 2a above the annular region 110b of the substrate support 11.

Next, a new ring assembly 120 is placed on the annular region 110b of the substrate support 11 from the transport device 2.

Specifically, the lifter 130 is raised, and as shown in Figure 10A, the inner edge ring 123 is transferred from the upper surface of the insulating ring 121 held by the transport arm 2a to the upper support portion 131a of the lifter 130, which has passed through the through hole 121a of the insulating ring 121.
At this time, as described above, the lower ends of the inclined portions of the through holes 121a of the insulating ring 121 and the grooves 123a of the inner edge ring 123 are formed to be larger than at least the transport accuracy of the inner edge ring 123 by the transport device 2. Therefore, even if there is a misalignment between the lift pins 131 and the through holes 121a and the grooves 123a due to the transport accuracy of the transport device 2, the lift pins 131 can be properly inserted into the through holes 121a and further guided to the bottom surfaces 123a1 of the grooves 123a.

Next, the lifter 130 continues to rise, and as shown in FIG. 10B, the insulating ring 121 is transferred from the transfer arm 2a to the lower support portion 131b of the lifter 130. At this time, the outer edge ring 122 on the insulating ring 121 is also transferred to the lower support portion 131b at the same time. At this time, the lifter 130 continues to rise until the step portion of the lower support portion 131b reaches the desired height H2.
In this embodiment, the through holes 121a of the insulating ring 121 and the grooves 123a of the inner edge ring 123 are formed so that their radial widths (first width W1 or third width W3) are larger than their circumferential widths (second width W2 or fourth width W4). Therefore, even if a misalignment occurs between the lift pins 131 and the through holes 121a due to processing tolerances or the like, the lift pins 131 can be properly inserted into the through holes 121a and further guided to the bottom surfaces 123a1 of the grooves 123a.
At this time, the lower support portion 131b of the lift pin 131 comes into contact with the inclined portion of the through hole 121a at two points, which causes the insulating ring 121 to move freely in the longitudinal direction of the through hole 121a around the lift pin 131. Therefore, even if there is a misalignment between the lift pin 131, the through hole 121a, and the groove 123a due to the various factors described above, the insulating ring 121 slides in the longitudinal direction of the through hole 121a, and the insulating ring 121 and the outer edge ring 122 can be appropriately positioned at the desired positions.
Similarly, the upper support portion 131a of the lift pin 131 makes line contact with the bottom surface 123a1 of the groove 123a, thereby allowing the inner edge ring 123 to be properly positioned at the desired position and preventing the inner edge ring 123 from shifting in position when the ring assembly 120 is subsequently placed.

Next, the transfer arm 2a is extracted from the plasma processing chamber 10. Also, the lifter 130 is lowered. As a result, the insulating ring 121, the outer edge ring 122, and the inner edge ring 123 are placed on the upper surface of the annular region 110b of the substrate support 11 and on the upper surface of the support 113. Specifically, the insulating ring 121 and the outer edge ring 122 are first placed on the upper surface of the support 113, and then the inner edge ring 123 is placed on the upper surface of the insulating ring 121 and on the upper surface of the annular region 110b of the substrate support 11.
In this way, a series of processes for placing the ring assembly 120 on the substrate support 11 is completed.

In the above embodiment, the insulating ring 121, outer edge ring 122, and inner edge ring 123 as the ring assembly 120 were transported and placed simultaneously, but any one of the insulating ring 121, outer edge ring 122, and inner edge ring 123 may be transported and placed independently.
In the above embodiment, the insulating ring 121, the outer edge ring 122, and the inner edge ring 123 forming the ring assembly 120 are transferred and carried out sequentially, but the insulating ring 121, the outer edge ring 122, and the inner edge ring 123 may be transferred and carried out simultaneously. In this case, the inner edge ring 123 may be transferred between the lift pins 131 and the transfer arm 2a and carried out from the plasma processing apparatus 1 while still placed on the insulating ring 121, i.e., integrally with the insulating ring 121.

<Modification of Edge Ring>
11A to 11C are diagrams showing examples of the configuration of an inner edge ring 223 according to another embodiment.
In another embodiment of the inner edge ring 223, at least one of the multiple grooves (three grooves 223a to 223c in the illustrated example) formed on the bottom surface side may be formed in a circular shape (FIG. 11B), and the remaining grooves (grooves 223b and 223c in the illustrated example) may be formed in an elongated hole shape (FIG. 11C).

In one embodiment, the circular groove 223a has a bottom surface 223a1 with a diameter (first diameter D1 in FIG. 11 ) that is substantially the same as the width (fifth width W5) of the upper support portion 131a of the lift pin 131. The bottom surface 223a1 of the groove 223a has a shape that fits with the shape of the tip end of the upper support portion 131a of the lift pin 131. In other words, the tip end of the upper support portion 131a is configured to be able to come into surface contact with the bottom surface 223a1 of the groove 223a formed in the inner edge ring 223.
Furthermore, a side surface 223a2 of groove 223a has an inclined portion (flared shape) formed so that a first diameter D1 of bottom surface 223a1 widens downward (toward the bottom surface of inner edge ring 223). It is desirable that the lower end of the inclined portion of groove 223a be formed to be at least larger than the transport accuracy of inner edge ring 223 by transport device 2.

In one embodiment, the slot-shaped grooves 223b and 223c have the same structure as the groove 123a of the inner edge ring 123 shown in the above embodiment. That is, the grooves 223b and 223c are formed so that the third width W3 extending in the radial direction of the inner edge ring 223 is larger than the fourth width W4 extending in the circumferential direction of the inner edge ring 223, which is perpendicular to the radial direction. The bottom surfaces 223b1 and 223c1 are shaped to fit with the tip end shape of the upper support portion 131a of the lift pin 131, particularly in the direction of extension of the fourth width W4. In addition, sloped portions are formed on the side surfaces 223b2 and 223c2 of the grooves 223b and 223c. It is desirable that the lower end of the sloped portion of the groove 123a be formed larger than at least the transport accuracy of the inner edge ring 123 by the transport device 2.

As shown in the above embodiment, if all three grooves 123a formed on the bottom surface of inner edge ring 123 have an elongated hole shape, inner edge ring 123 will be free to move in the longitudinal direction of grooves 123a, as described above, which may cause inner edge ring 123 to slide and become misaligned.
Therefore, in an inner edge ring 223 according to another embodiment, at least one groove 223a is formed in a circular shape, and the inner edge ring 223 is positioned using the circular groove 223a as a base point. That is, a plasma processing system according to one embodiment includes a plasma processing chamber 10, a substrate support 11, an annular member 223, at least three cylindrical lift pins 131, and at least one actuator 132. The substrate support 11 is disposed in the plasma processing chamber 10 and has a substrate support surface 110a and a ring support surface 110b. The annular member 223 is disposed on the ring support surface 110b and has at least three grooves 223a-223c on its lower surface. The first groove 223a of the at least three grooves 223a-223c has a circular bottom surface 223a1 when viewed from above. Of the at least three grooves 223a-223c, the second groove 223b and the third groove 223c have bottom surfaces 223b1, 223c1 having a first width W3 in a radial direction R3 of the annular member 223 and a second width W4 in a circumferential direction C3 of the annular member 223. The second width W4 is smaller than the first width W3. At least three cylindrical lift pins 131 are disposed below the ring support surface 110b and correspond to the at least three grooves 223a-223c, respectively. Each of the at least three cylindrical lift pins 131 is configured to contact the bottom surface of the grooves 223a-223c of the annular member 223, thereby supporting the annular member 223 from below. The at least one actuator 132 is configured to move the at least three cylindrical lift pins 131 vertically.
As a result, the tip end of upper support portion 131a, which is formed to be approximately the same size, and bottom surface 223a1 of groove 223a fit together and come into surface contact, thereby suppressing sliding at least in the horizontal direction between inner edge ring 223 and lifter 130. Furthermore, because the remaining grooves 223b and 223c are formed in an elongated hole shape, even if there is a misalignment between grooves 223b and 223c and lift pins 131 due to the various factors described above, the misalignment can be corrected to appropriately guide lift pins 131 into grooves 223b and 223c, thereby positioning inner edge ring 223 at the desired position.

In the above embodiment, of the at least three grooves 223a to 223c, one groove 223a is formed in a circular shape, and the remaining grooves 223b and 223c are formed in an elongated hole shape. However, if, for example, the inner edge ring 223 can be properly positioned, each of the at least three grooves 223a to 223c may be formed in a circular shape.
In other words, in one embodiment, each of the at least three grooves 223a-223c of the conductive ring 123 is defined by a bottom surface 223a1 having a shape that can mate with the tip of the upper support portion 131a of the lift pin 131, and a flared side surface 223a2 that widens downward from the bottom surface.

<Modifications of Grooves Formed in Inner Edge Ring>
The cross-sectional shapes of the elongated grooves formed in the inner edge ring (groove 123a of inner edge ring 123, grooves 223b and 223c of inner edge ring 223) are not limited to those in the above embodiment.
12A , groove 123a may have a flat bottom surface 123a1″ having a substantially flat surface, vertical side surfaces 123a3 as vertical walls extending vertically downward from flat bottom surface 123a1″, and flared side surfaces 123a2 as widening walls that widen downward from vertical side surfaces 123a3. In this case, it is desirable that a fourth width W4 in the lateral direction of groove 123a (the width of the vertical side surface 123a3 portion) be formed slightly larger than the diameter (fifth width W5) of upper support portion 131a to enable sliding relative to lift pin 131. In this case, the contact mode between upper support portion 131a and groove 123a is one-point contact.
12B, the groove 123a may be formed with a curved surface having a larger curvature than the tip (hemispherical shape 131a1) of the hemispherical lift pin 131. In other words, the groove 123a may have only a curved bottom surface 123a1', and may not have vertical side surfaces 123a3 and flared side surfaces 123a2. In this case, the groove 123a is configured to be slidable relative to the lift pin 131. In this case, the contact between the upper support portion 131a and the groove 123a is one-point contact.
For example, as shown in FIG. 12C , groove 123a may have a flat bottom surface 123a1″ having a substantially flat surface, and flared side surfaces 123a2 as widening walls that widen downward from flat bottom surface 123a1″. In other words, compared to the above embodiment, in the example shown in FIG. 12C , flat bottom surface 123a1″ is not formed in a shape that fits with lift pin 131. In this case, the contact method between upper support portion 131a and groove 123a is three-point contact.

Furthermore, in the examples shown in Figures 5 and 12A to 12C above, the flared side surface 123a2 that spreads downward from the bottom surface 123a1 (or vertical side surface 123a3) of the groove 123a is configured as a side surface that is linear in side view and whose width spreads downward at a constant rate, but the flared side surface 123a2 may also be configured as a side surface that is curved in side view.
12D , groove 123a may have curved bottom surface 123a1′ having a curved shape with a larger curvature than the tip end (hemispherical shape 131a1) of hemispherical lift pin 131, and flared curved side surface 123a4 that widens downward from curved bottom surface 123a1′ and curves upward (toward the opposite side from lift pin 131). In this case, upper support portion 131a and groove 123a contact each other at one point.

The curvature of the flared curved side surface 123a4 is not particularly limited. In other words, a groove 123a is formed in the inner edge ring 123 provided in the plasma processing apparatus 1 according to the technology disclosed herein, and the groove 123a is composed of a bottom surface 123a1 and one or more side surfaces (side surfaces 123a2, 123a3, and 123a4) having any curvature value greater than "0". A side surface with a curvature of "0" means that the side surface is linear in side view (side surface 123a2). A curvature greater than "0" means that the side surface is curved in side view (side surface 123a4).

As described above, groove 123a (grooves 223b, 223c) may be formed in any cross-sectional shape. In this case, the contact method between upper support portion 131a and groove 123a varies depending on the cross-sectional shape. From the viewpoint of facilitating the alignment of upper support portion 131a and groove 123a, it is preferable that the contact area between upper support portion 131a and groove 123a is small. Furthermore, from the viewpoint of improving the installation accuracy of upper support portion 131a and groove 123a, it is preferable that the contact area between upper support portion 131a and groove 123a is large.
In this way, the cross-sectional shape of the groove 123a (grooves 223b, 223c) can be designed appropriately depending on the purpose.

Furthermore, the cross-sectional shape of the circular groove formed in the inner edge ring (groove 223a of inner edge ring 223) is not limited to that in the above embodiment.
For example, as shown in FIG. 13A , groove 223a may have a flat bottom surface 223a1″ having a substantially flat surface, vertical side surfaces 223a3 as vertical walls extending vertically downward from flat bottom surface 223a1″, and flared side surfaces 223a2 as widening walls widening downward from vertical side surfaces 223a3. In this case, it is desirable that first diameter D1 (the width of vertical side surfaces 223a3) of groove 223a be slightly larger than the diameter (fifth width W5) of upper support portion 131a so that the tip end of lift pin 131 can appropriately contact flat bottom surface 223a1″. In this case, upper support portion 131a and groove 123a contact each other at one point.
13B, groove 223a may be formed with a curved surface having a larger curvature than the tip of hemispherical lift pin 131. In other words, groove 223a may have only a curved bottom surface 223a1′, and may not have flared side surfaces 223a2 and vertical side surfaces 223a3. In this case, the contact between upper support portion 131a and groove 223a is one-point contact.
For example, as shown in FIG. 13C , groove 223a may have a flat bottom surface 223a1″ having a substantially flat surface, and flared side surfaces 223a2 as widening walls that widen downward from flat bottom surface 223a1″. In other words, compared to the example shown in FIG. 11 , in the example shown in FIG. 13C , flat bottom surface 223a1″ is not formed in a shape that fits with lift pin 131. In this case, the contact method between upper support portion 131a and groove 223a is three-point contact.
Although not shown, the flared side surface 123a2 of the circular groove 223a may also be configured by a curved side surface in a side view, as in the example shown in Fig. 12D. In other words, the circular groove 223a may have a flared curved side surface (not shown).

Various exemplary embodiments have been described above, but the present invention is not limited to the exemplary embodiments described above, and various additions, omissions, substitutions, and modifications may be made. Furthermore, elements from different embodiments can be combined to form other embodiments.

REFERENCE SIGNS LIST 1 Plasma processing apparatus 10 Plasma processing chamber 11 Substrate support 12 Plasma generation section 110b Annular region 121 Insulating ring 121a Through hole 121a1 Upper hole portion 121a2 Lower hole portion 123 Inner edge ring 123a Groove 123a1 Bottom surface 131 Lift pin 131a Upper support portion 131b Lower support portion 132 Actuator W1 First width W2 Second width W3 Third width W4 Fourth width

Claims (11)

a plasma processing chamber;
a substrate support disposed within the plasma processing chamber, the substrate support having a substrate support surface and a ring support surface;
an insulating ring disposed on the ring support surface and having at least three through holes, each of the at least three through holes having an upper hole portion and a lower hole portion, the upper hole portion having a first width in a radial direction of the insulating ring and a second width in a circumferential direction of the insulating ring, the second width being smaller than the first width, and the lower hole portion having a flared shape widening downward when viewed from the side;
a conductive ring supported by the insulating ring and having at least three grooves on its lower surface corresponding to the at least three through holes, each of the at least three grooves having a third width in a radial direction of the conductive ring and a fourth width in a circumferential direction of the conductive ring, the fourth width being smaller than the third width;
at least three lift pins arranged below the ring support surface and corresponding to each of the at least three grooves, each of the at least three lift pins having an upper support portion and a lower support portion, the upper support portion being configured to support the conductive ring from below by contacting a bottom surface of the groove in the conductive ring through the through hole in the insulating ring, and the lower support portion being configured to support the insulating ring from below by contacting an inclined surface of the insulating ring that defines the lower hole portion;
and at least one actuator configured to move the at least three lift pins vertically. The plasma processing apparatus of claim 1, wherein the lower support portion of the lift pin is configured to contact the inclined surface at two points in the radial direction of the insulating ring without contacting the inclined surface in the circumferential direction of the insulating ring. A plasma processing apparatus as described in claim 1 or 2, wherein each of the at least three through holes in the insulating ring has a rectangular shape when viewed from above. 3. The plasma processing apparatus of claim 1, wherein the upper support portion has a cylindrical shape with a first diameter smaller than the second width, and the lower support portion has a cylindrical shape with a second diameter larger than the second width. The plasma processing apparatus according to claim 1 , wherein the tip of the upper support portion of the lift pin has a hemispherical shape. The plasma processing apparatus according to claim 1 , wherein the tip of the upper support portion of the lift pin has a flat surface. Each of the at least three grooves in the conductive ring comprises:
A flat bottom surface;
a vertical side surface extending downward from the flat bottom surface;
3. The plasma processing apparatus according to claim 1, wherein the plasma processing apparatus is defined by a flared side surface that widens downward from the vertical side surface. 3. The plasma processing apparatus of claim 1 , wherein each of the at least three grooves in the conductive ring is defined by a curved bottom surface. Each of the at least three grooves in the conductive ring comprises:
A flat bottom surface;
3. The plasma processing apparatus according to claim 1 , wherein the plasma processing apparatus is defined by a flared side surface that widens downward from the flat bottom surface. Each of the at least three grooves in the conductive ring comprises:
a bottom surface having a shape that can be fitted onto the tip of the upper support portion of the lift pin;
3. The plasma processing apparatus according to claim 1, further comprising a flared side surface that widens downward from the bottom surface. 3. The plasma processing apparatus of claim 1, further comprising an additional conductive ring arranged to surround the conductive ring and the insulating ring, wherein at least a portion of the additional conductive ring vertically overlaps an outer portion of the insulating ring.