Substrate support and plasma processing apparatus

Abstract

Provided is a substrate support comprising an electrostatic chuck for supporting a substrate and an edge ring, and a base that supports the electrostatic chuck, the electrostatic chuck including: a first region that has a first upper surface and is configured to support a substrate that is placed on the first upper surface; a second region that has a second upper surface, is provided around the first region, and is configured to support an edge ring that is placed on the second upper surface; a first electrode that is provided in the first region and to which a direct-current voltage is applied; a second electrode that is provided under the first electrode and to which a first bias power is supplied; a third electrode that is provided under the second electrode and to which the first bias power is supplied; and a first gas supply path disposed between the second electrode and the third electrode. The substrate support further includes a first power supply path that is in electrical contact with the second electrode and the third electrode to supply the first bias power.

Description

Technical Field

[0001] The present disclosure relates to a substrate support and a plasma processing apparatus.

Background Art

[0002] Patent Document 1 discloses a mounting table provided with an electrostatic chuck for supporting a substrate and an edge ring. The electrostatic chuck disclosed in Patent Document 1 has a suction electrode. When a DC voltage is applied to the suction electrode, an electrostatic attraction force is generated, and the substrate is held by the electrostatic attraction force. Further, the electrostatic chuck has a bias electrode to which a bias power for ion drawing is applied.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The technology according to the present disclosure suppresses the occurrence of abnormal discharge in a substrate support having an electrostatic chuck and a flow path for a heat transfer gas.

Means for Solving the Problems

[0005] One aspect of the present disclosure is a substrate support comprising an electrostatic chuck for supporting a substrate and an edge ring, and a base for supporting the electrostatic chuck, wherein the electrostatic chuck has a first region having a first upper surface and configured to support a substrate placed on the first upper surface, a second region having a second upper surface and provided around the first region and configured to support an edge ring placed on the second upper surface, a first electrode provided in the first region to which a DC voltage is applied, a second electrode provided below the first electrode to which a first bias power is supplied, a third electrode provided below the second electrode to which the first bias power is supplied, and a first gas supply path disposed between the second electrode and the third electrode, and further comprises a first power supply path that electrically contacts the second electrode and the third electrode and supplies the first bias power. [Effects of the Invention]

[0006] According to this disclosure, in a substrate support having an electrostatic chuck and a heat transfer gas flow path, the occurrence of abnormal discharge can be suppressed. [Brief explanation of the drawing]

[0007] [Figure 1] This is a diagram illustrating an example configuration of a plasma processing system. [Figure 2] This is a diagram illustrating an example configuration of a capacitively coupled plasma processing apparatus. [Figure 3] This is a cross-sectional view showing a schematic example of the configuration of a substrate support. [Figure 4] This diagram shows the positional relationship between the fifth electrode and the second via. [Figure 5] This diagram shows the positional relationship between the sixth electrode and the third via. [Figure 6] This figure shows another example of the first internal power supply circuit. [Figure 7] This figure shows another example of the first power supply terminal. [Figure 8] This figure shows a specific example of the positional relationship between the third and fifth electrodes. [Modes for carrying out the invention]

[0008] In the manufacturing process of semiconductor devices, plasma treatments such as etching and film deposition are performed on substrates such as semiconductor wafers (hereinafter referred to as "wafers") using plasma. Plasma treatment is performed while the substrate is held by electrostatic force in an electrostatic chuck of a substrate support.

[0009] Since the temperature of the substrate affects the outcome of the plasma treatment, the substrate support is equipped with a temperature control mechanism to adjust the temperature of the electrostatic chuck, as well as a flow path to supply heat transfer gas between the substrate mounting surface of the electrostatic chuck and the back surface of the substrate.

[0010] However, if a flow path for heat transfer gas is provided in the substrate support, abnormal discharge may occur within the flow path.

[0011] Furthermore, in order to improve processing speeds such as etching rates, bias electrodes for ion drawing, i.e., biasing, are provided within the electrostatic chuck. While it has been considered to suppress abnormal discharge by adding a bias electrode in addition to the heat transfer gas flow path, there is still room for improvement.

[0012] Therefore, the technology described herein further suppresses the occurrence of abnormal discharge in a substrate support having an electrostatic chuck and a heat transfer gas flow path.

[0013] The substrate support and plasma processing apparatus according to this embodiment will be described below with reference to the drawings. In this specification and the drawings, elements having substantially the same functional configuration are denoted by the same reference numerals, and redundant explanations will be omitted.

[0014] <Plasma Treatment System> First, a plasma processing system including a plasma processing apparatus according to one embodiment will be described using Figure 1. Figure 1 is a diagram illustrating an example of the configuration of a plasma processing system.

[0015] In one embodiment, a 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. Further, the plasma processing chamber 10 has at least one gas supply port for supplying at least one processing gas to the plasma processing space and at least one gas discharge port for discharging gas from the plasma processing space. The gas supply port is connected to a gas supply unit 20 described later, and the gas discharge 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.

[0016] 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), ECR plasma (Electron-Cyclotron-resonance plasma), helicon wave plasma (HWP), surface wave plasma (SWP), or the like. Also, various types of plasma generation units including an AC (Alternating Current) plasma generation unit and a DC (Direct Current) plasma generation unit may be used. In one embodiment, the AC signal (AC power) used in the AC plasma generation unit has a frequency within the range of 100 kHz to 10 GHz. Accordingly, the AC signal includes RF (Radio Frequency) signals and microwave signals. In one embodiment, the RF signal has a frequency within the range of 100 kHz to 150 MHz.

[0017] The control unit 2 processes computer-executable instructions that cause the plasma processing apparatus 1 to execute various processes described in the present disclosure. The control unit 2 may be configured to control each element of the plasma processing apparatus 1 to execute the 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 is realized by, for example, a computer 2a. The processing unit 2a1 may be configured to perform various control operations by reading a program from the storage unit 2a2 and executing the read program. This program may be stored in the storage unit 2a2 in advance, or may be acquired via a medium when necessary. The acquired program is stored in the storage unit 2a2 and read from the storage unit 2a2 by the processing unit 2a1 and executed. The medium may be various storage media readable by the computer 2a, or may be a communication line connected to the communication interface 2a3. The processing unit 2a1 may be a CPU (Central Processing Unit). The storage unit 2a2 may include a RAM (Random Access Memory), a ROM (Read Only Memory), a HDD (Hard Disk Drive), a SSD (Solid State Drive), or a combination thereof. The communication interface 2a3 may communicate with the plasma processing apparatus 1 via a communication line such as a LAN (Local Area Network).

[0018] <Plasma Processing Apparatus> Hereinafter, a configuration example of a capacitively coupled plasma processing apparatus as an example of the plasma processing apparatus 1 will be described. FIG. 2 is a diagram for explaining a configuration example of a capacitively coupled plasma processing apparatus.

[0019] The capacitively coupled plasma processing apparatus 1 includes a plasma processing chamber 10, a gas supply unit 20, a power supply 30, and an exhaust system 40. The plasma processing apparatus 1 also includes a substrate support 11 and a gas introduction unit. The gas introduction unit is configured to introduce at least one processing gas into the plasma processing chamber 10. The gas introduction unit includes a shower head 13. The substrate support 11 is located inside the plasma processing chamber 10. The shower head 13 is located above the substrate support 11. In one embodiment, the shower head 13 constitutes 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 shower head 13, the side walls 10a of the plasma processing chamber 10, and the substrate support 11. The plasma processing chamber 10 is grounded. The shower head 13 and the substrate support 11 are electrically insulated from the housing of the plasma processing chamber 10.

[0020] 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 the substrate W and an annular region 111b for supporting the ring assembly 112. A wafer is an example of the 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 placed on the central region 111a of the main body 111, and the ring assembly 112 is placed 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 the substrate support surface for supporting the substrate W, and the annular region 111b is also called the ring support surface for supporting the ring assembly 112.

[0021] In one embodiment, the main body 111 includes a base 113 and an electrostatic chuck 114. The base 113 includes a conductive member. The conductive member of the base 113 can function as a lower electrode. The electrostatic chuck 114 is positioned on the base 113. The electrostatic chuck 114 includes a ceramic member 300 and a first electrode 321 as an electrostatic electrode positioned within the ceramic member 300. The ceramic member 300 has a central region 111a. In one embodiment, the ceramic member 300 also has an annular region 111b. Other members surrounding the electrostatic chuck 114, such as an annular electrostatic chuck or an annular insulating member, may also have an annular region 111b. In this case, the ring assembly 112 may be positioned on the annular electrostatic chuck or the annular insulating member, or on both the electrostatic chuck 114 and the annular insulating member. Furthermore, a second electrode 322 (see Figure 2 below), which serves as a bias electrode and is coupled to the RF power supply 31 and / or DC power supply 32 (described later) and supplied with a bias RF signal and / or DC signal, is arranged within the ceramic member 300. In addition, at least one RF / DC electrode, which is coupled to the RF power supply 31 and / or DC power supply 32 (described later) and functions as a lower electrode, may be arranged within the ceramic member 300. Note that the conductive member of the base 113 and at least one RF / DC electrode may function as multiple lower electrodes. Also, the first electrode 321, which serves as an electrostatic electrode, may function as a lower electrode. Therefore, the substrate support 11 includes at least one lower electrode.

[0022] 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 covering ring. The edge rings are formed of a conductive or insulating material, and the covering rings are formed of an insulating material.

[0023] The substrate support 11 may also include a temperature control module configured to adjust at least one of the electrostatic chuck 114, the ring assembly 112, and the substrate W to a target temperature. The temperature control module may include a heater, a heat transfer medium, a flow path 113a, or a combination thereof. A heat transfer fluid, such as brine or gas, flows through the flow path 113a. In one embodiment, the flow path 113a is formed within the base 113, and one or more heaters are arranged within the ceramic member 300 of the electrostatic chuck 114. The substrate support 11 also includes a heat transfer gas supply unit configured to supply heat transfer gas to the gap between the back surface of the substrate W and the central region 111a.

[0024] The showerhead 13 is configured to introduce at least one processing gas from the gas supply unit 20 into the plasma processing space 10s. The showerhead 13 has at least one gas supply port 13a, at least one gas diffusion chamber 13b, and a plurality of gas inlet ports 13c. The processing gas supplied to the gas supply port 13a passes through the gas diffusion chamber 13b and is introduced into the plasma processing space 10s through the plurality of gas inlet ports 13c. The showerhead 13 also includes at least one upper electrode. In addition to the showerhead 13, the gas introduction unit may also include one or more side gas injectors (SGIs) attached to one or more openings formed in the side wall 10a.

[0025] 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 processing gas to the shower head 13 from a corresponding gas source 21 via a corresponding flow controller 22. Each flow controller 22 may include, for example, a mass flow controller or a pressure-controlled flow controller. Furthermore, the gas supply unit 20 may include at least one flow modulation device that modulates or pulses the flow rate of at least one processing gas.

[0026] 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 plasma to be formed from at least one processing gas supplied to the plasma processing space 10s. Thus, the RF power supply 31 can function as at least part of the plasma generation unit 12. In addition, by supplying a bias RF signal to the second electrode (see Figure 2 below), a bias potential is generated on the substrate W, and ionic components in the formed plasma can be drawn into the substrate W.

[0027] In one embodiment, the RF power supply 31 includes a first RF generation unit 31a and a second RF generation unit 31b. The first RF generation unit 31a is coupled to 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 generation unit 31a may be configured to generate a plurality of source RF signals having different frequencies. One or more generated source RF signals are supplied to at least one lower electrode and / or at least one upper electrode.

[0028] The second RF generation unit 31b is coupled to the second electrode 322 (see Figure 2, described later) 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 generation unit 31b may be configured to generate a plurality of bias RF signals having different frequencies. One or more generated 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.

[0029] 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 generation unit 32a and a second DC generation unit 32b. In one embodiment, the first DC generation unit 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 at least one lower electrode. In one embodiment, the second DC generation unit 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 at least one upper electrode.

[0030] 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 a combination thereof pulse waveform. In one embodiment, a waveform generation unit for generating a sequence of voltage pulses from the DC signal is connected between the first DC generation unit 32a and at least one lower electrode. Thus, the first DC generation unit 32a and the waveform generation unit constitute a voltage pulse generation unit. When the second DC generation unit 32b and the waveform generation unit constitute a voltage pulse generation unit, the voltage pulse generation unit is connected to at least one upper electrode. The voltage pulses may have positive or negative polarity. The sequence of voltage pulses may also include one or more positive voltage pulses and one or more negative voltage pulses within one period. The first and second DC generation units 32a and 32b may be provided in addition to the RF power supply 31, and the first DC generation unit 32a may be provided in place of the second RF generation unit 31b.

[0031] The exhaust system 40 may be connected to, for example, a gas outlet 10e located at the bottom of the plasma processing chamber 10. The exhaust system 40 may include a pressure regulating valve and a vacuum pump. The pressure regulating valve regulates the pressure in the plasma processing space 10s. The vacuum pump may include a turbomolecular pump, a dry pump, or a combination thereof.

[0032] <Substrate supporter> Next, the configuration of the substrate support 11 will be explained using Figures 3 to 5. Figure 3 is a schematic cross-sectional view showing an example of the configuration of the substrate support 11. Figure 4 is a diagram showing the positional relationship between the fifth electrode and the second via, which will be described later. Figure 5 is a diagram showing the positional relationship between the sixth electrode and the third via, which will be described later.

[0033] As described above, the substrate support 11 includes a main body 111 and a ring assembly 112. In the example shown in Figure 3, the substrate support 11 includes an edge ring E as the ring assembly 112. In one embodiment, the main body 111 includes a base 113 and an electrostatic chuck 114.

[0034] The base 113 has a main body 200 made of a conductive material such as Al. The aforementioned flow path 113a is formed in the main body 200. In one embodiment, the base 113 and the electrostatic chuck 114 are integrated by means of adhesive, for example. A source RF signal for plasma generation can be supplied to the base 113.

[0035] The electrostatic chuck 114 is for supporting the substrate W, and more specifically, for supporting the substrate W and the edge ring E. More specifically, the electrostatic chuck 114 is for electrostatically adsorbing and supporting the substrate W and the edge ring E.

[0036] The electrostatic chuck 114 has a ceramic member 300 as described above. The ceramic member 300 is formed in a substantially disc shape. The material of the ceramic member 300 can be a ceramic such as aluminum oxide or aluminum nitride.

[0037] The ceramic member 300 has a first region 301 which is the aforementioned central region 111a and a second region 302 which is the aforementioned annular region 111b.

[0038] The first region 301 is a region having a substantially disc shape and has a first upper surface 311. The first region 301 is configured to support the substrate W which is placed on the first upper surface 311.

[0039] The second region 302 is a region having an annular shape in plan view and has a second upper surface 312. The first region 301 and the second region 302 are concentric. The second region 302 is configured to support the edge ring E which is placed on the second upper surface 312. In one embodiment, the first region 301 is formed to have a smaller diameter than the diameter of the substrate W, and the first upper surface 311 is higher than the second upper surface 312, so that when the substrate W is placed on the first upper surface 311, the peripheral edge of the substrate W protrudes from the first region 301.

[0040] The first region 301 and the second region 302 may be formed as a single unit, or they may be formed as separate entities.

[0041] Furthermore, the first region 301 is provided with first to third electrodes 321 to 323. The first electrode 321 is located inside the first region 301, and a DC voltage from a DC power supply (not shown) is applied to it. The resulting electrostatic force causes the substrate W to be attracted and held to the first upper surface 311. In other words, the first electrode 321 is an electrode for electrostatic attraction of the substrate W. The first electrode 321 is formed in a circular shape when viewed from above.

[0042] The second electrode 322 is located below the first electrode 321 within the first region 301. The second electrode 322 is connected to a bias power supply (e.g., a DC power supply 32) via a first power supply path 361, described later, and is supplied with first bias power from the bias power supply. When the first bias power is supplied to the second electrode 322, ions in the plasma are drawn toward the substrate W on the first upper surface 311. This allows for adjustment of the process speed across the entire surface of the substrate W, and in the case of etching, it is possible to improve the etching speed across the entire surface of the substrate W. The second electrode 322 is formed in a circular shape, for example, with approximately the same diameter as the first electrode 321 in a plan view.

[0043] The third electrode 323 is located below the second electrode 322 within the first region 301. Like the second electrode 322, the third electrode 323 is connected to a bias power supply via the first power supply path 361 (described later), and first bias power is supplied from the bias power supply (e.g., DC power supply 32). When the first bias power is supplied to the third electrode 323 in the same way as to the second electrode 322, the parts between the second electrode 322 and the third electrode 323 become approximately the same potential. The third electrode 323 is formed in a circular shape, for example, with approximately the same diameter as the first electrode 321 and the second electrode 322 in a plan view. Note that the diameters of the first to third electrodes 321 to 323 may differ from each other.

[0044] In one embodiment, the first bias power supplied to the second electrode 322 and the third electrode 323 is the bias power of a pulsed DC signal.

[0045] Furthermore, the first region 301 is provided with a first gas discharge port 331, a first gas supply passage 341, and a first gas inlet port 351. The first gas discharge port 331 is located in the upper part of the first region 301, the first gas supply passage 341 is located between the second electrode 322 and the third electrode 323 in the first region 301, and the first gas inlet port 351 is located in the lower part of the first region 301. Although only one first gas discharge port 331 is shown in the figure, there are many (for example, 30 or more) provided. In this embodiment, the number of first gas inlet ports 351 is less than the number of first gas discharge ports 331, for example, one. However, the number of first gas inlet ports 351 may be the same as the number of first gas discharge ports 331.

[0046] Each first gas discharge hole 331 discharges a heat transfer gas such as helium between the back surface of the substrate W placed on the first upper surface 311 and the first upper surface 311. Each first gas discharge hole 331 has one end opening to the first upper surface 311 and the other end connected to the first gas supply passage 341. Each first gas discharge hole 331 is formed, for example, to extend in the vertical direction and to penetrate holes 321a and 322a provided in the portions of the first electrode 321 and the second electrode 322 corresponding to each first gas discharge hole 331.

[0047] The first gas supply passage 341 diffuses the heat transfer gas introduced from the first gas inlet 351 horizontally between the second electrode 322 and the third electrode 323 and supplies it to a plurality of first gas discharge holes 331.

[0048] The first gas inlet 351 is connected to the first gas supply passage 341 at one end and to a heat transfer gas supply unit (not shown) at the other end, so as to be fluidly continuous. The first gas inlet 351 introduces heat transfer gas from the heat transfer gas supply unit into the first gas supply passage 341.

[0049] The heat transfer gas supply unit described above may include one or more gas sources and one or more flow controllers. In one embodiment, the gas supply unit is configured to supply gas from a gas source to the first gas inlet 351 via a flow controller. Each flow controller may include, for example, a mass flow controller or a pressure-controlled flow controller.

[0050] In one embodiment, the first gas introduction hole 351 is formed to extend, for example, in the vertical direction and to penetrate a hole 323a provided in the portion of the third electrode 323 corresponding to the first gas introduction hole 351, and the lower end of the first gas introduction hole 351 opens to the lower surface of the electrostatic chuck 114. In this case, the heat transfer gas from the heat transfer gas supply unit is introduced into the first gas introduction hole 351 via a gas introduction passage 113b provided in the base 113. The gas introduction passage 113b is formed to extend, for example, in the vertical direction and to penetrate the base 113. The inner circumferential wall of the gas introduction passage 113b is covered with an insulating member 113c.

[0051] Furthermore, the second region 302 is provided with fourth to sixth electrodes 324 to 326. The fourth electrode 324 is located inside the second region 302, and a DC voltage from a DC power supply (not shown) is applied to it. The resulting electrostatic force causes the edge ring E to be attracted and held to the second upper surface 312. In other words, the fourth electrode 324 is an electrode for electrostatic attraction of the edge ring E. The fourth electrode 324 is formed in an annular shape in plan view, and more specifically, in a circular shape in plan view.

[0052] Furthermore, in this embodiment, the fourth electrode 324 is, for example, a bipolar type including a pair of electrodes 324a and 324b. In this case, electrodes 324a and 324b are each formed in an annular shape in plan view. However, the fourth electrode 324 may also be a unipolar type.

[0053] The fifth electrode 325 is located below the fourth electrode 324 inside the second region 302. The fifth electrode 325 is connected to a bias power supply (e.g., a DC power supply 32) via a second power supply path 362, described later, and second bias power is supplied from the bias power supply. By adjusting the magnitude of the second bias power supplied to the second electrode 322, the shape of the ion sheath above the edge ring E on the second upper surface 312 can be adjusted. The fifth electrode 325 is formed in an annular shape in plan view, and more specifically, in a circular shape in plan view. Furthermore, the inner diameter of the fifth electrode 325 is approximately the same as the inner diameter of the fourth electrode 324 (specifically, the inner diameter of the inner electrode 324a), and the outer diameter of the fifth electrode 325 is approximately the same as the outer diameter of the fourth electrode 324 (specifically, the outer diameter of the outer electrode 324b).

[0054] The sixth electrode 326 is located below the fifth electrode 325 within the second region 302. The sixth electrode 326 is connected to a bias power supply (e.g., a DC power supply 32) via a third power supply path 363, described later, and a third bias power is supplied from the bias power supply. When the second bias power is supplied to the fifth electrode 325 and the third bias power, which is approximately equal in magnitude to the second bias power, is supplied to the sixth electrode 326, the portions between the fifth electrode 325 and the sixth electrode 326 become approximately at the same potential. The sixth electrode 326 is formed in an annular shape, for example, with approximately the same diameter as the fifth electrode 325 in a plan view. The inner and outer diameters of the fourth to sixth electrodes 324 to 326 may be different from each other.

[0055] In one embodiment, the second bias power supplied to the fifth electrode 325 and the third bias power supplied to the sixth electrode 326 are bias powers of a pulsed DC signal. Furthermore, the first bias power supplied to the second electrode 322 and the third electrode 323, the second bias power supplied to the fifth electrode 325, and the third bias power supplied to the sixth electrode 326 are each controlled independently. The second bias power supplied to the fifth electrode 325 and the third bias power supplied to the sixth electrode 326 may also be controlled independently.

[0056] Furthermore, the second region 302 is provided with a second gas discharge port 332 and a second gas supply passage 342. The second gas discharge port 332 is located in the upper part of the second region 302, and the second gas supply passage 342 is located between the fifth electrode 325 and the sixth electrode 326 in the second region 302. Although only one second gas discharge port 332 is shown in the figure, there are many (for example, 10 or more) provided along the circumferential direction centered on the central axis of the electrostatic chuck 114.

[0057] Each second gas discharge port 332 discharges a heat transfer gas such as helium between the back surface of the edge ring E, which is placed on the second upper surface 312, and the second upper surface 312. Each second gas discharge port 332 has one end opening to the second upper surface 312 and the other end connected to the second gas supply passage 342. Each second gas discharge port 332 is formed, for example, to extend in the vertical direction and pass between electrodes 324a and 324b, and to penetrate a hole 325a provided in the portion of the fifth electrode 325 corresponding to each second gas discharge port 332.

[0058] The second gas supply passage 342 supplies heat transfer gas introduced from a heat transfer gas supply unit (not shown) to a plurality of second gas discharge holes 332 by diffusing the heat transfer gas horizontally between the fifth electrode 325 and the sixth electrode 326.

[0059] The heat transfer gas supply unit described above may include one or more gas sources and one or more flow controllers. In one embodiment, the gas supply unit is configured to supply gas from a gas source to the first gas inlet 351 via a flow controller. Each flow controller may include, for example, a mass flow controller or a pressure-controlled flow controller.

[0060] Furthermore, the heat transfer gas is supplied from the heat transfer gas supply unit to the second gas supply passage 342, for example, through a gas inlet formed in the second region 302, similar to the first gas inlet hole 351, and a gas inlet formed in the base 113, similar to the gas inlet passage 113b.

[0061] Furthermore, the substrate support 11 has a first power supply path 361 that electrically contacts the second electrode 322 and the third electrode 323 and supplies first bias power to these second electrode 322 and the third electrode 323. This first power supply path 361 has a first power supply terminal 371 and a first via 381 as a first internal power supply path.

[0062] The first power supply terminal 371 is located inside the base 113 and supplies first bias power from a bias power supply (e.g., DC power supply 32) to the first via 381. The first power supply terminal 371 is formed to extend vertically, for example, and penetrate the base 113. In this case, the first power supply terminal 371 is provided in a through hole 201 that penetrates the main body 200 of the base 113 vertically. The inner circumferential wall of the through hole 201 is covered with an insulating member 201a.

[0063] The first via 381 electrically contacts the first power supply terminal 371 and is positioned inside the first region 301 of the electrostatic chuck 114. The first via 381 is formed, for example, to extend downward from the center of the second electrode 322 to the lower surface of the electrostatic chuck 114. In this case, the upper end of the first via 381 is electrically and physically connected to the center of the second electrode 322. The first via 381 also penetrates the center of the third electrode 323, and the first via 381 and the third electrode 323 are electrically and physically connected at the penetration point.

[0064] Furthermore, the substrate support 11 has a second power supply path 362 that electrically contacts the fifth electrode 325 and supplies second bias power to the fifth electrode 325. This second power supply path 362 has a second power supply terminal 372 and a second via 382 as a second internal power supply path. The second vias 382 are provided in groups of three or more, at approximately equal intervals, along the circumferential direction centered on the center of the fifth electrode 325, i.e., the central axis of the electrostatic chuck 114, as shown in Figure 4. A second power supply terminal 372 is provided for each second via 382.

[0065] Each second power supply terminal 372 is located inside the base 113, as shown in Figure 3, and supplies second bias power from a bias power supply (e.g., DC power supply 32) to the second via 382. Each second power supply terminal 372 is formed to extend, for example, in the vertical direction and penetrate the base 113. In this case, each second power supply terminal 372 is provided in a through hole 202 that penetrates the main body 200 of the base 113 in the vertical direction. The inner circumferential wall of the through hole 202 is covered with an insulating member 202a.

[0066] Each second via 382 is electrically in contact with the second power supply terminal 372 and is located inside the second region 302 of the electrostatic chuck 114. Each second via 382 is formed such that, for example, it extends downward from the fifth electrode 325, passes through a hole 326a provided in the portion of the sixth electrode 326 corresponding to each second via 382, ​​and reaches the lower surface of the electrostatic chuck 114. In this case, the upper end of the second via 382 is electrically and physically connected to the fifth electrode 325. Note that the second via 382 and the sixth electrode 326 are not physically connected and are electrically insulated from each other.

[0067] Furthermore, the substrate support 11 has a third power supply path 363 that electrically contacts the sixth electrode 326 and supplies third bias power to the sixth electrode 326. This third power supply path 363 has a third power supply terminal 373 and a third via 383 as a third internal power supply path. Three or more third vias 383 are provided at approximately equal intervals along the circumferential direction centered on the center of the sixth electrode 326, i.e., the central axis of the electrostatic chuck 114, as shown in Figure 5. Note that when the same number of third vias 383 and second vias 382 are provided at equal intervals along the circumferential direction, the third vias 383 and second vias 382 may be provided alternately.

[0068] Each third power supply terminal 373 is located inside the base 113 and supplies third bias power from a bias power supply (not shown) to the third via 383. Each third power supply terminal 373 is formed to extend, for example, vertically and penetrate the base 113. In this case, each third power supply terminal 373 is provided in a through hole 203 that penetrates the main body 200 of the base 113 vertically. The inner circumferential wall of the through hole 203 is covered with an insulating member 203a.

[0069] Each third via 383 electrically contacts the third power supply terminal 373 and is located inside the second region 302 of the electrostatic chuck 114. Each third via 383 is formed, for example, to extend downward from the sixth electrode 326 to the lower surface of the electrostatic chuck 114. In this case, the upper end of the third via 383 is electrically and physically connected to the sixth electrode 326.

[0070] The second via 382 and the third via 383 are each formed in a columnar shape (e.g., cylindrical shape) that extends vertically, for example. The material of the second via 382 and the third via 383 is a conductive material such as conductive ceramic or metal.

[0071] <Main effects and benefits> Next, the main effects and advantages of the substrate support 11 according to this embodiment will be explained. Recently, there has been a demand for high-power plasma processing, such as deep-hole etching processes for 3D NAND flash memory. When processing at high power, the substrate W becomes hot, so a heat transfer gas is supplied between the back surface of the substrate W and the substrate support so that the substrate W can be efficiently cooled via the substrate support. In addition, since variations in the temperature of the substrate W within the substrate surface affect the product yield, numerous heat transfer gas discharge holes are provided on the surface of the substrate support 11 on which the substrate W is placed, so that the temperature of the substrate W is uniform within the surface. When providing such a large number of discharge holes, a gas diffusion channel may be used, as in the first gas supply channel 341 of this embodiment, which diffuses the heat transfer gas horizontally, i.e., parallel to the substrate surface, and supplies the heat transfer gas to each discharge hole. Compared to providing an individual supply channel for each discharge hole, using the above-described gas diffusion channel allows for more efficient distribution of the heat transfer gas.

[0072] It is preferable to provide the gas diffusion channel in the electrostatic chuck rather than in the base. This is because providing it in the base would increase the volume of the gas channel within the base, requiring a larger amount of insulating material to cover the inner wall of the channel to suppress abnormal discharges, thus increasing costs. Furthermore, providing the gas diffusion channel in the base would affect the design flexibility of the refrigerant channel for temperature control within the base, making it difficult to achieve the desired temperature distribution on the substrate mounting surface of the base.

[0073] In other words, a structure that incorporates a gas diffusion channel into the electrostatic chuck is expected to improve the diffusion rate of the heat transfer gas, increase the design flexibility of the refrigerant channel in the base, and reduce costs.

[0074] However, simply providing a gas diffusion channel in an electrostatic chuck can lead to a potential difference between the substrate and the base when high-frequency power for plasma generation is supplied to the base. This can cause a potential difference within the gas diffusion channel, potentially resulting in abnormal discharge within the gas diffusion channel.

[0075] Furthermore, in order to improve the processing speed such as the etching rate, it is preferable to provide a bias electrode in the electrostatic chuck to which bias power is supplied for ion drawing, such as the second electrode 322 of the substrate support 11 in the embodiment.

[0076] Therefore, in the substrate support 11 according to this embodiment, a first gas supply passage 341, which is the gas diffusion channel described above, is provided below the second electrode 322, to which the first bias power is supplied for ion drawing, within the electrostatic chuck 114. Furthermore, in the substrate support 11 according to this embodiment, a third electrode 323, to which the first bias power is supplied in the same way as the second electrode 322, is provided further below the first gas supply passage 341. In other words, in the substrate support 11, the first gas supply passage 341 is sandwiched between the second electrode 322 and the third electrode 323, to which the first bias power is supplied. Consequently, because the potential difference generated within the first gas supply passage 341 is small, it is possible to suppress the occurrence of abnormal discharge within the first gas supply passage 341. Furthermore, in this embodiment, both the second electrode 322 and the third electrode 323 are provided. Compared to the case where only the second electrode 322 is provided, it is possible to suppress the intrusion of an electric field below the second electrode 322 through the hole 322a for the first gas discharge hole 331 of the second electrode 322. Therefore, it is possible to suppress the generation of a potential difference in the vicinity below the hole 322a of the second electrode 322 in the first gas supply passage 341 and the first gas discharge hole 331, thereby suppressing the occurrence of abnormal discharge.

[0077] In other words, according to this embodiment, as described above, it is possible to achieve both a structure in which a gas diffusion channel is provided in an electrostatic chuck, which is expected to improve the diffusion rate of the heat transfer gas, increase the degree of freedom in designing the refrigerant flow path of the base, and reduce costs, and a structure in which a bias electrode is provided inside the electrostatic chuck to improve processing speed.

[0078] Furthermore, in the substrate support 11 according to this embodiment, for the same reasons as with the first gas supply passage 341, it is possible to suppress the occurrence of abnormal discharge in the second gas supply passage 342, which is a gas diffusion passage for the edge ring E.

[0079] In this embodiment, the first via 381 is connected to the central portion of both the second electrode 322 and the third electrode 323. This makes it possible to make the potentials of the second electrode 322 and the third electrode 323 more uniform in the plane compared to the case where the first via 381 is connected to only one peripheral portion of each electrode.

[0080] Furthermore, in this embodiment, the second via 382 and the third via 383 are each provided in groups of three or more along the circumferential direction at approximately equal intervals. This makes it possible to make the potentials of the fifth electrode 325 and the sixth electrode 326 more uniform in the circumferential direction compared to the case where only one second via 382 and one third via 383 are connected.

[0081] (modified version) Figure 6 shows another example of the first internal power supply path. In the above example, the first via 381 was provided as a first internal power supply path that electrically contacts the first power supply terminal 371 and is located inside the first region 301 of the electrostatic chuck 114. In the example shown in Figure 6, the electrostatic chuck 114 includes a first internal power supply path 400 having a first distribution power supply path 401 and a second distribution power supply path 402.

[0082] The first power distribution line 401 makes electrical contact with the second electrode 322, but does not make electrical contact with the third electrode 323. The second power distribution line 402 makes electrical contact with the third electrode 323, but does not make electrical contact with the second electrode 322. The first power distribution line 401 and the second power distribution line 402 then make electrical contact with the first power supply terminal 371.

[0083] In this configuration, by using different forming materials for the first and second power distribution channels 401 and 402, the electrical resistance values ​​of the first and second power distribution channels 401 and 402 can be made different from each other, and a potential difference can be applied to the second electrode 322 and the third electrode 323 within a range where abnormal discharge does not occur. This makes it possible to adjust the effect of the third electrode 323 on the etching characteristics. In other words, in this configuration, it is possible to suppress the generation of a potential difference within the first gas supply channel 341 while ensuring the desired etching characteristics.

[0084] Figure 7 shows another example of the first power supply terminal. In the example of Figure 7, similar to the example of Figure 6, the electrostatic chuck 114 includes a first internal power supply path 400A having a first distribution power supply path 401A that electrically contacts the second electrode 322 and a second distribution power supply path 402A that electrically contacts the third electrode 323. However, unlike the example of Figure 6, the first power supply terminal 371A that electrically contacts the first internal power supply path 400A has a first distribution power supply terminal 411 that electrically contacts the first distribution power supply path 401A and a second distribution power supply terminal 412 that electrically contacts the second distribution power supply path 402A.

[0085] The first distribution power supply terminal 411 and the second distribution power supply terminal 412 are connected to the same power source (e.g., DC power supply 32). In this case, as in the example in Figure 6, by making the electrical resistance values ​​of the first distribution power supply path 401A and the second distribution power supply path 402A different from each other, a potential difference can be applied to the second electrode 322 and the third electrode 323 within a range that does not cause abnormal discharge.

[0086] Furthermore, the first distribution power supply terminal 411 and the second distribution power supply terminal 412 may each be connected to different power sources (not shown). In this case, even if the electrical resistance values ​​of the first distribution power supply path 401A and the second distribution power supply path 402A are not made different, a potential difference can be applied to the second electrode 322 and the third electrode 323 within a range that does not cause abnormal discharge by making the applied voltage to the first distribution power supply terminal 411 and the applied voltage to the second distribution power supply terminal 412 different.

[0087] Figure 8 shows a specific example of the positional relationship between the third electrode 323 and the fifth electrode 325. The third electrode 323 and the fifth electrode 325 may be provided on the same plane, as shown in Figure 8. The electrostatic chuck 114 is manufactured, for example, by providing each electrode on a flat plate of insulating material and stacking the plates. However, by providing them on the same plane as described above, the number of flat plates of insulating material can be reduced, thus enabling the manufacture of the electrostatic chuck 114 at a low cost.

[0088] Although various exemplary embodiments have been described above, the invention is not limited to the exemplary embodiments described above, and various additions, omissions, substitutions, and modifications may be made. Furthermore, it is possible to combine elements from different embodiments to form other embodiments. [Explanation of symbols]

[0089] 1. Plasma processing equipment 10 Plasma processing chamber 11 Substrate supporter 112 Ring Assembly 113 Base 114 Electrostatic Chuck 301 First area 302 Second area 311 1st top surface 312 2nd top surface 321 1st electrode 322 2nd electrode 323 3rd electrode 324 4th electrode 325 5th electrode 326 6th electrode 341 First Gas Supply Line 361 1st power supply path 362 2nd power supply path 363 Third power supply route E Edge Ring W board

Claims

1. An electrostatic chuck for supporting the substrate and edge ring, The system comprises a base for supporting the electrostatic chuck, The electrostatic chuck is, A first region having a first upper surface and configured to support a substrate placed on the first upper surface, A second region having a second upper surface, provided around the first region and configured to support an edge ring placed on the second upper surface, A first electrode provided in the first region to which a DC voltage is applied, A second electrode is provided below the first electrode and to which a first bias power is supplied, A third electrode is provided below the second electrode and to which the first bias power is supplied, It has a first gas supply path disposed between the second electrode and the third electrode, A substrate support further having a first power supply path that electrically contacts the second electrode and the third electrode and supplies the first bias power.

2. The aforementioned first power supply line is, The first power supply terminal is located inside the base, The substrate support according to claim 1, further comprising: a first internal power supply path that electrically contacts the first power supply terminal and is located within the first region.

3. The first internal power supply path is, A first power distribution path that is in electrical contact with the second electrode, It has a second power distribution path that is in electrical contact with the third electrode, The substrate support according to claim 2, wherein the first distribution power supply path and the second distribution power supply path are in electrical contact with the first power supply terminal.

4. The first power supply terminal is, A first distribution power supply terminal that is electrically in contact with the first distribution power supply path, The substrate support according to claim 3, further comprising a second distribution power supply terminal that electrically contacts the second distribution power supply path.

5. The circuit board support according to claim 4, wherein the first distribution power supply terminal and the second distribution power supply terminal are connected to the same power supply.

6. The circuit board support according to claim 4, wherein the first distribution power supply terminal and the second distribution power supply terminal are each connected to different power sources.

7. The electrostatic chuck is, A fourth electrode is provided in the second region to which a DC voltage is applied, A fifth electrode is provided below the fourth electrode and to which a second bias power is supplied, A sixth electrode is provided below the fifth electrode, to which a third bias power is supplied, It has a second gas supply path positioned between the fifth electrode and the sixth electrode, A second power supply path that electrically contacts the fifth electrode and supplies the second bias power, A substrate support according to any one of claims 1 to 6, further comprising a third power supply path that electrically contacts the sixth electrode and supplies the third bias power.

8. The aforementioned second power supply line is A second power supply terminal is located inside the base, The substrate support according to claim 7, further comprising a second internal power supply path that electrically contacts the second power supply terminal and is located within the second region.

9. The aforementioned third power supply line is A third power supply terminal is located inside the base, The substrate support according to claim 8, further comprising a third internal power supply path that electrically contacts the third power supply terminal and is located within the second region.

10. The circuit board support according to claim 9, wherein the second power supply terminal and the third power supply terminal are connected to the same power supply.

11. The circuit board support according to claim 9, wherein the second power supply terminal and the third power supply terminal are each connected to different power sources.

12. The substrate support according to claim 7, wherein the third electrode and the fifth electrode are provided on the same plane.

13. The substrate support according to claim 7, wherein the fifth electrode and the sixth electrode are formed in an annular shape in plan view.

14. The substrate support according to claim 13, wherein the second power supply path and the third power supply path are each provided in three or more locations along the circumferential direction.

15. The substrate support according to claim 7, wherein the fourth electrode is an electrode for electrostatic adsorption of the edge ring.

16. The substrate support according to claim 7, wherein the fourth electrode is a bipolar electrode.

17. The substrate support according to any one of claims 1 to 6, wherein the first electrode is an electrode for electrostatic adsorption of the substrate.

18. A substrate support having an electrostatic chuck for supporting a substrate and an edge ring, and a base for supporting the electrostatic chuck, A plasma processing chamber in which a substrate support base is positioned inside is provided. The electrostatic chuck is, A first region having a first upper surface and configured to support a substrate placed on the first upper surface, A second region having a second upper surface, provided around the first region and configured to support an edge ring placed on the second upper surface, A first electrode provided in the first region to which a DC voltage is applied, A second electrode is provided below the first electrode and to which a first bias power is supplied, A third electrode is provided below the second electrode and to which the first bias power is supplied, A first gas supply path is disposed between the second electrode and the third electrode, A fourth electrode is provided in the second region to which a DC voltage is applied, A fifth electrode is provided below the fourth electrode and to which a second bias power is supplied, A sixth electrode is provided below the fifth electrode, to which a third bias power is supplied, It has a second gas supply path positioned between the fifth electrode and the sixth electrode, The aforementioned substrate support is, A first power supply path that electrically contacts the second electrode and the third electrode and supplies the first bias power, A second power supply path that electrically contacts the fifth electrode and supplies the second bias power, A plasma processing apparatus further comprising a third power supply path that electrically contacts the sixth electrode and supplies the third bias power.

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