Filter circuit

Abstract

The present application relates to a filter circuit. The filter circuit is provided in a plasma processing apparatus that uses plasma generated using electric power of a first frequency of 4 MHz or more and electric power of a second frequency of 100 Hz or more and less than 4 MHz, and the filter circuit includes a first filter section and a second filter section. The first filter section is provided in a wiring between a conductive member in the plasma processing apparatus and a power supply section for supplying electric power of a third frequency of less than 100 Hz or direct current to the conductive member. The second filter section is provided in the wiring between the first filter section and the power supply section. The first filter section has a first coil connected in series to the wiring and a series resonance circuit connected between the wiring and a ground. The second filter section has a second coil connected in series to the wiring between the first coil and the power supply section.

Description

Technical Field

[0001] Various aspects and embodiments of this disclosure relate to a filter circuit. Background Technology

[0002] For example, Patent Document 1 discloses a plasma processing apparatus comprising a first power supply 28 and a second power supply 30, a heating wire 40, a heater power supply 58, and a filter 54. The first filter 84A of the filter 54 includes a primary filter composed of an air-core coil AL1 and a capacitor AC1, and a secondary filter composed of a toroidal coil AL2 and a capacitor AC2.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2014-229565 Summary of the Invention

[0006] The problem the invention aims to solve

[0007] This disclosure provides a filter circuit capable of suppressing power leakage from the plasma supply unit and suppressing power loss in the plasma.

[0008] Solution for solving the problem

[0009] One aspect of this disclosure is a filter circuit disposed in a plasma processing apparatus that uses plasma for processing. The plasma is generated using power at a first frequency of 4 MHz or higher and power at a second frequency of 100 Hz or higher but less than 4 MHz. The filter circuit includes a first filter section and a second filter section. The first filter section is disposed in wiring between a conductive member disposed within the plasma processing apparatus and a power supply section for supplying control power to the conductive member. The control power is power at a third frequency less than 100 Hz or DC power. The second filter section is disposed in the portion of the wiring between the first filter section and the power supply section. Furthermore, the first filter section includes: a first coil connected in series to the wiring, the first coil having no core material or having a first core material with a relative permeability less than 10; and a series resonant circuit connected between the wiring between the conductive member and the power supply section and ground, the series resonant circuit having a coil and a capacitor connected in series. The second filter section includes a second coil connected in series to the portion of the wiring between the first coil and the power supply section, the second coil having a second core material with a relative permeability of 10 or higher.

[0010] The effects of the invention

[0011] According to various aspects and embodiments of this disclosure, it is possible to suppress the leakage of power supplied to the plasma to the power supply unit and to suppress the power loss of the plasma. Attached Figure Description

[0012] Figure 1 This is a schematic cross-sectional view illustrating an example of a plasma processing apparatus according to one embodiment of the present disclosure.

[0013] Figure 2 This is a top view showing an example of the regional distribution of electrostatic chucks.

[0014] Figure 3 This is a diagram illustrating an example of a filter circuit in one embodiment of the present disclosure.

[0015] Figure 4 This is a graph showing an example of the impedance of a wiring relative to its parasitic capacitance at a frequency of 400kHz.

[0016] Figure 5 This is a diagram illustrating an example of the magnitude of the voltage generated on the surface of the substrate relative to the magnitude of the 13MHz RF power.

[0017] Figure 6 This is a diagram illustrating an example of the magnitude of the voltage generated on the surface of a substrate relative to the magnitude of RF power at 400 kHz.

[0018] Figure 7 These are diagrams illustrating other examples of filter circuits.

[0019] Figure 8 These are diagrams illustrating other examples of filter circuits.

[0020] Figure 9 This is a schematic cross-sectional view showing other examples of plasma processing apparatus.

[0021] Figure 10 It means Figure 9 A diagram illustrating an example of a filter circuit in the plasma processing apparatus.

[0022] Figure 11 These are diagrams illustrating other examples of filter circuits.

[0023] Figure 12 These are diagrams illustrating other examples of filter circuits.

[0024] Figure 13 These are diagrams illustrating other examples of filter circuits. Detailed Implementation

[0025] The embodiments of the disclosed filter circuit will now be described in detail with reference to the accompanying drawings. However, the disclosed filter circuit is not intended to be limited by the embodiments described below.

[0026] Furthermore, some devices that use plasma to process substrates include conductive components such as heaters for regulating the substrate temperature. A filter circuit is provided in the wiring between the conductive component and the power supply unit to prevent the RF power used in plasma generation from flowing through the conductive component to the power supply unit, such as the heater control circuit. Additionally, when supplying the plasma with power of a first frequency and power of a second frequency, the filter circuit needs to prevent both the first and second frequency power from flowing through the conductive component to the power supply unit, such as the heater control circuit.

[0027] However, when the impedance of the filter circuit is low at the first and second frequencies, the power supplied to the plasma at the first and second frequencies decreases, resulting in power loss in the plasma.

[0028] Therefore, this disclosure provides a technique that can suppress the leakage of power supplied to the plasma into the power supply unit and suppress the power loss of the plasma.

[0029] [Structure of Plasma Processing Unit 1]

[0030] Figure 1 This is a schematic cross-sectional view showing an example of a plasma processing apparatus 1 according to one embodiment of the present disclosure. The plasma processing apparatus 1 in this embodiment is an apparatus for processing a substrate W using capacitively coupled plasma. The plasma processing apparatus 1 includes an apparatus body 2 and a control device 3.

[0031] The main body 2 of the device has a generally cylindrical chamber 10, for example, made of aluminum or stainless steel. The chamber 10 is safely grounded. A generally circular plate-shaped base 12 is disposed within the chamber 10. The base 12 is made of, for example, aluminum, and also functions as a lower electrode. The base 12 is supported by a cylindrical support 14 extending vertically upward from the bottom of the chamber 10. The support 14 is formed of an insulating material such as ceramic. Therefore, the support 14 is electrically insulated from the chamber 10.

[0032] A conductive cylindrical support portion 16 extending vertically upward from the bottom of the chamber 10 is provided along the outer periphery of the support portion 14. An annular exhaust path 18 is formed between the cylindrical support portion 16 and the inner wall of the chamber 10. An exhaust port 20 is provided at the bottom of the exhaust path 18. The exhaust port 20 is connected to an exhaust device 24, which includes a turbomolecular pump, via an exhaust pipe 22. The exhaust device 24 depressurizes the processing space within the chamber 10 to a desired vacuum level. An opening for loading and unloading the substrate W is formed on the side wall of the chamber 10, and this opening is opened and closed by a gate valve 26.

[0033] The base station 12 is electrically connected to a first RF (Radio Frequency) power supply 28 and a second RF power supply 30 via a matching unit 32 and a power supply rod 34. The first RF power supply 28 primarily supplies RF power of a first frequency, conducive to plasma generation, to the base station 12 via the matching unit 32 and the power supply rod 34. In this embodiment, the first frequency is a frequency of 4 MHz or higher. In this embodiment, the first frequency is, for example, 13 MHz. The matching unit 32 is used to achieve impedance matching between the first RF power supply 28 and the plasma load.

[0034] The second RF power supply 30 primarily supplies high-frequency power at a second frequency to the base station 12 via the matching unit 32 and the power supply rod 34, which helps to attract ions to the substrate W on the base station 12. In this embodiment, the second frequency is a frequency above 100 Hz and less than 4 MHz. In this embodiment, the second frequency is, for example, 400 kHz. The matching unit 32 is also used to achieve impedance matching between the second RF power supply 30 and the plasma load.

[0035] The power supply rod 34 is a generally cylindrical conductor. The upper end of the power supply rod 34 is connected to the center of the lower surface of the base 12, and the lower end of the power supply rod 34 is connected to the matching unit 32. Furthermore, a generally cylindrical cover 35 with an inner diameter larger than the outer diameter of the power supply rod 34 is disposed around the power supply rod 34. The upper end of the cover 35 is connected to an opening formed on the bottom surface of the chamber 10, and the lower end of the cover 35 is connected to the housing of the matching unit 32.

[0036] An edge ring 36 and an electrostatic chuck 38 are disposed on the base 12. The edge ring 36 is sometimes referred to as a focusing ring. A substrate W, which is the object to be processed, is disposed on the upper surface of the electrostatic chuck 38. The edge ring 36 has a generally annular shape, and the electrostatic chuck 38 has a generally circular shape. The edge ring 36 is disposed around the electrostatic chuck 38 in a manner that surrounds the electrostatic chuck 38 and the substrate W on the electrostatic chuck 38. The edge ring 36 is formed, for example, from silicon (Si), silicon carbide (SiC), carbon (C), silicon dioxide (SiO2), etc.

[0037] The electrostatic chuck 38 has multiple heaters 40, a dielectric 42, and electrodes 44. The heaters 40 are examples of conductive components. The electrodes 44 and the multiple heaters 40 are encapsulated within the dielectric 42. The electrodes 44 are electrically connected to a DC power supply 45 located outside the chamber 10 via a switch 46. The electrodes 44 hold the substrate W to the upper surface of the electrostatic chuck 38 by a Coulomb force generated by a DC voltage applied by the DC power supply 45. Furthermore, the wiring between the switch 46 and the electrodes 44 is covered by an insulator; this wiring passes through the power supply rod 34 and extends from below through the base 12 to connect to the electrodes 44 of the electrostatic chuck 38.

[0038] Each heater 40 heats up in response to the control power supplied by the heater control unit 58. In this embodiment, the control power supplied by the heater control unit 58 is AC power with a frequency of 50Hz. Alternatively, the control power supplied from the heater control unit 58 to each heater 40 may be AC ​​power or DC power with a third frequency of less than 100Hz.

[0039] The upper surface of the electrostatic chuck 38, for example Figure 2 As shown, it has multiple regions 380. Figure 2 This is a top view showing an example of the regional distribution of the electrostatic chuck 38. In this embodiment, multiple regions 380 are arranged concentrically around the central axis X of the electrostatic chuck 38. Each heater 40 (heater 40-1, heater 40-2, ...) is arranged such that one is provided in each region 380.

[0040] Return to Figure 1 Continuing with the explanation, each heater 40 is connected to the heater control unit 58 via a filter circuit 500, which includes a first filter circuit 51 and a second filter circuit 52. The heater control unit 58 controls the power supplied to each heater 40 via the filter circuit 500, thereby controlling the heat output of each heater 40. The heater control unit is an example of a power supply unit. Details regarding the filter circuit 500 will be described later. In this embodiment, n regions (n ​​being an integer greater than or equal to 2) are provided on the upper surface of the electrostatic chuck 38, and n heaters 40 are disposed on the electrostatic chuck 38. Hereinafter, to distinguish each heater 40, they will be referred to as heater 40-1, heater 40-2, ..., heater 40-n.

[0041] An annular flow path 60 is provided inside the base 12, and refrigerant from a cooling unit (not shown) is circulated and supplied into the flow path 60. The base 12 is cooled by the refrigerant circulating in the flow path 60, and the substrate W on the electrostatic chuck 38 is cooled via the electrostatic chuck 38 provided on the base 12. In addition, a pipe 62 is provided between the base 12 and the electrostatic chuck 38 for supplying a heat transfer gas such as He gas between the electrostatic chuck 38 and the substrate W. The heat transfer rate between the electrostatic chuck 38 and the substrate W can be controlled by controlling the pressure of the heat transfer gas supplied between the electrostatic chuck 38 and the substrate W via the pipe 62.

[0042] At the top of chamber 10, a spray head 64 is positioned facing the base 12. The spray head 64 also functions as an upper electrode, which faces the base 12, which functions as a lower electrode. The space S between the spray head 64 and the base 12 becomes the plasma generation space. The spray head 64 has an electrode plate 66 facing the base 12 and a support body 68 that supports the electrode plate 66 from above in a detachable manner. The electrode plate 66 is formed, for example, of Si or SiC. The support body 68 is formed, for example, of aluminum that has undergone anodizing treatment.

[0043] A diffusion chamber 70 is formed inside the support 68. Multiple gas outlets 72, extending from the diffusion chamber 70 to the base 12, are formed on the electrode plate 66 and the support 68. A gas inlet 70a, communicating with the diffusion chamber 70, is provided on the upper part of the support 68. The gas inlet 70a is connected to a processing gas supply unit 74 via a pipe 76. In the processing gas supply unit 74, a gas supply source is provided for each type of gas. Flow controllers, valves, etc., are connected to each gas supply source. Furthermore, various gases, whose flow rates are controlled by the flow controllers, are supplied to the space S via the pipe 76.

[0044] Each part of the main body 2 is controlled, for example, by a control device 3 equipped with a memory, a processor, and an input / output interface. The memory stores control programs, processing procedures, etc. The processor reads from the memory and executes the control programs, and controls each part of the main body 2 via the input / output interface based on the processes stored in the memory. Thus, the plasma processing apparatus 1 performs processes such as etching using plasma on the substrate W.

[0045] [Structure of filter circuit 500]

[0046] Figure 3This diagram illustrates an example of a filter circuit 500 according to one embodiment of the present disclosure. The filter circuit 500 has a plurality of independent filter circuits 50-1 to 50-n. Furthermore, hereinafter, without distinguishing between the plurality of independent filter circuits 50-1 to 50-n, they will be collectively referred to as independent filter circuit 50.

[0047] Each independent filter circuit 50 has a first filter circuit 51 for suppressing power at a first frequency and a second filter circuit 52 for suppressing power at a second frequency. The first filter circuit 51 is provided in the wiring between the heater 40 provided within the plasma processing apparatus 1 and the heater control unit 58 for supplying control power to the heater 40. The first filter circuit 51 is an example of a first filter unit. The first filter circuit 51 has a coil 510 and a series resonant circuit 511. The coil 510 is an air-core coil without a core material (i.e., the core material is air). This suppresses the heating of the coil 510. The coil 510 is an example of a first coil. In this embodiment, the inductance of the coil 510 is, for example, 50 μH. Alternatively, the coil 510 may have a core material with a permeability of less than 10, such as a resin material like PTFE (polytetrafluoroethylene). A core material with a permeability of less than 10 is an example of a first core material.

[0048] A series resonant circuit 511 is connected between the coil 510 and ground. The series resonant circuit 511 includes a coil 512 and a capacitor 513. The coil 512 and the capacitor 513 are connected in series. In the series resonant circuit 511, constants for the coil 512 and the capacitor 513 are selected such that the resonant frequency of the series resonant circuit 511 is near a first frequency (e.g., a first frequency). The coil 512 is, for example, an air-core coil without a core, similar to the coil 510. In this embodiment, the inductance of the coil 512 is, for example, 6 μH. Furthermore, the capacitance of the capacitor 513 is, for example, 500 pF or less; in this embodiment, the capacitance of the capacitor 513 is, for example, 25 pF. Therefore, the resonant frequency of the series resonant circuit 511 is approximately 13 MHz.

[0049] Furthermore, the first filter circuit 51 suppresses power at a first frequency higher than the second frequency, therefore, it is preferable to make the wiring between the heater 40 and the first filter circuit 51 extremely short. This reduces the impact of stray capacitance and inductance from the wiring and also suppresses RF power leakage. The capacitor 513 is preferably, for example, a vacuum capacitor. This results in extremely low resistivity of the capacitor 513, in addition to its dielectric constant being independent of temperature, thus minimizing the heat generated by the RF power current.

[0050] The node between coil 510 and series resonant circuit 511 is connected to second filter circuit 52 via wiring 514. Wiring 514 between first filter circuit 51 and second filter circuit 52 is shielded by metal conduit 53.

[0051] The second filter circuit 52 is disposed in the wiring section between the first filter circuit 51 and the heater control unit 58. The second filter circuit 52 is an example of a second filter section. The second filter circuit 52 includes a coil 520 and a capacitor 521. The coil 520 is a cored coil having a core material with a permeability of 10 or higher. The coil 520 is an example of a second coil. In this embodiment, the inductance of the coil 520 is, for example, 10 mH. Examples of core materials with a permeability of 10 or higher include powder-pressed parts, permalloy, and cobalt-based amorphous materials.

[0052] Capacitor 521 is connected between coil 520 and ground. The second filter circuit 52 suppresses power at a second frequency lower than the first frequency, thus allowing the second filter circuit 52 to be positioned further from the heater 40 than the first filter circuit 51. Therefore, capacitor 521 is less susceptible to heat from the heater 40, enabling the use of ceramic capacitors, which are less expensive than vacuum capacitors. In this embodiment, the capacitance of capacitor 521 is, for example, 2000 pF. Furthermore, if a capacitor with the same capacitance as capacitor 521 is provided at the output terminal of the heater control unit 58 connected to wiring 522, capacitor 521 may not be required within the second filter circuit 52.

[0053] The node between coil 520 and capacitor 521 is connected to heater control unit 58 via wiring 522. In this embodiment, adjustments are made to ensure that the parasitic capacitance of the wiring between heater 40 and first filter circuit 51, the wiring 514 between first filter circuit 51 and second filter circuit 52, and the wiring 522 between second filter circuit 52 and heater control unit 58 is 500pF or less. For example, the adjustment is made by increasing the distance between the wiring and ground by inserting a spacer such as resin between the wiring and ground, thereby reducing the parasitic capacitance between the wiring and ground to 500pF or less.

[0054] [Parasitic capacitance of wiring]

[0055] Figure 4 This graph illustrates an example of the impedance of a wiring relative to its parasitic capacitance at a frequency of 400kHz. At 400kHz, the impedance of the plasma is approximately 800Ω. Therefore, when the wiring impedance is below 800Ω, more power flows into the filter circuit 500 than into the plasma, resulting in increased power loss.

[0056] For example Figure 4 As shown, with a parasitic capacitance of 500pF, the impedance of the wiring is approximately 800Ω. Additionally, for example... Figure 4 As shown, the lower the parasitic capacitance of the wiring, the higher the impedance of the wiring. Therefore, it is preferable to keep the parasitic capacitance of the wiring below 500pF to suppress power loss.

[0057] [RF current flow]

[0058] For a frequency of, for example, 13 MHz (the first frequency), the impedance of coil 510 is, for example, as high as about 4 kΩ. Therefore, coil 510 can suppress the RF current flowing from the plasma to the first filter circuit 51 via heater 40 to a low level. In addition, the resonant frequency of series resonant circuit 511 is set to a frequency near 13 MHz (e.g., 13 MHz). Therefore, the RF current at the frequency of 13 MHz passing through coil 510 flows to ground via series resonant circuit 511 and hardly flows to the second filter circuit 52.

[0059] Furthermore, when the plasma voltage at 13MHz is 5kVpp, the plasma voltage leaking into the first filter circuit 51 via the heater 40 is suppressed to below 100Vpp by the approximately 4kΩ coil 510 and the less than 1Ω series resonant circuit 511. The plasma voltage suppressed to below 100Vpp by the first filter circuit 51 is further suppressed to below 40Vpp by the coil 520 and capacitor 521 of the second filter circuit 52. Since below 40Vpp is within the operating guarantee range of the heater control unit 58, the plasma voltage has almost no impact on the operation of the heater control unit 58.

[0060] Figure 5 This is a graph illustrating an example of the magnitude of the voltage generated on the surface of substrate W relative to the magnitude of 13MHz RF power. Figure 5 The diagram below illustrates the voltage without the filter circuit 500 as a comparative example. For example... Figure 5 As shown, in the case where the filter circuit 500 of this embodiment is used, the magnitude of the voltage generated on the surface of the substrate W is almost unchanged compared to the case where the filter circuit 500 is not used.

[0061] On the other hand, for a frequency of, for example, 400 kHz (the second frequency), the impedance of coil 510 is, for example, about 900 Ω. The impedance of coil 510 is equal to or greater than the impedance of the plasma at 400 kHz, and the impedance of the wiring from heater 40 to heater control unit 58 is also equal to or greater than the impedance of the plasma at 400 kHz. Therefore, compared to the RF current at a frequency of 13 MHz, the RF current at a frequency of 400 kHz flows into the filter circuit 500 more, but there is also sufficient current flowing in the plasma.

[0062] Furthermore, when the plasma voltage at 400 kHz is 5 kVpp, the plasma voltage leaking from heater 40 to the first filter circuit 51 is suppressed to below 4.5 kVpp by the voltage division of the approximately 100 Ω coil 510 and the approximately 1 kΩ series resonant circuit 511. The plasma voltage suppressed to below 4.5 kVpp by the first filter circuit 51 is further suppressed to less than 40 Vpp by the voltage division of the coil 520 and capacitor 521 of the second filter circuit 52. Since less than 40 Vpp is within the operating guarantee range of the heater control unit 58, the plasma voltage has almost no impact on the operation of the heater control unit 58.

[0063] Figure 6 This is a diagram illustrating an example of the magnitude of the voltage generated on the surface of substrate W relative to the magnitude of the RF power at 400 kHz. Figure 6 The diagram illustrates, as a comparative example, the voltage when filter circuit 500 is disconnected (i.e., the impedance of the filter circuit is infinitely large), or in other words, when filter circuit 500 is not present. For example... Figure 6 As shown, in the case where the filter circuit 500 of this embodiment is used, the magnitude of the voltage generated on the surface of the substrate W remains almost unchanged compared to the case where the filter circuit 500 is not used. Therefore, when the filter circuit 500 of this embodiment is used, the plasma processing performance on the substrate W can be maintained, and the power of the plasma flowing into the heater control unit 58 can be suppressed.

[0064] In this embodiment, power at a first frequency and power at a second frequency are supplied to the base 12, and control power from the heater control unit 58 is supplied to the heater 40 located near the base 12. Therefore, when the filter circuit 500 is insufficient in suppressing leakage of power at the first and second frequencies to the heater control unit 58, a large portion of the power supplied to the base 12 at the first and second frequencies leaks into the heater control unit 58. This results in increased plasma power loss. In contrast, the filter circuit 500 of this embodiment can sufficiently suppress leakage of power at the first and second frequencies to the heater control unit 58. Therefore, the filter circuit 500 of this embodiment is particularly effective in plasma processing apparatus 1 with a structure that supplies power at the first and second frequencies to the base 12 located near the heater 40.

[0065] Here, the filter circuit 500 is required to have three functions.

[0066] (1) The power loss supplied to the plasma is minimized by setting up the filter circuit 500. When the impedance of the filter circuit 500 is low, the current based on the first frequency power and the second frequency power supplied to the base 12 flows not only into the plasma but also into the filter circuit 500 via the heater 40. This results in the loss of the first frequency power and the second frequency power.

[0067] (2) No first-frequency power or second-frequency power flows into the heater control unit 58 connected to the filter circuit 500. Sometimes a large voltage, such as about 5kVpp, is applied to the base 12, which is supplied with first-frequency power and second-frequency power. On the other hand, the heater control unit 58 sometimes malfunctions or breaks down when a voltage of, for example, tens of V or more is applied. It is necessary to reduce the 5kVpp voltage leaking from the base 12 side to tens of Vpp on the heater control unit 58 side through the independent filter circuit 50.

[0068] (3) As in (1) and (2) above, the filter circuit 500 is required to have the function of sufficiently suppressing the current and voltage flowing into the heater 40, and on the other hand, it is required to transmit the current supplied from the heater control unit 58 with minimal loss.

[0069] Conventional filter circuits can only handle frequencies above 10MHz or frequencies below 10MHz, but the filter circuit 500 of this embodiment can handle both frequencies simultaneously.

[0070] The above describes one embodiment. As described above, the filter circuit 500 in this embodiment is provided in a plasma processing apparatus 1 that uses plasma for processing. The plasma is generated using power at a first frequency of 4 MHz or higher and power at a second frequency of 100 Hz or higher but less than 4 MHz. The filter circuit 500 includes a first filter circuit 51 and a second filter circuit 52. The first filter circuit 51 is provided in the wiring between a heater 40 provided in the plasma processing apparatus 1 and a heater control unit 58 for supplying control power to the heater 40. This control power is power at a third frequency of less than 100 Hz or DC power. The second filter circuit 52 is provided in the portion of the wiring between the first filter circuit 51 and the heater control unit 58. In addition, the first filter circuit 51 includes: a coil 510 connected in series to the wiring, the coil 510 having no core material or having a first core material with a relative permeability of less than 10; and a series resonant circuit 511 connected between the wiring and ground, the wiring being the wiring between the heater 40 and the heater control unit 58, the series resonant circuit 511 having a coil 512 and a capacitor 513 connected in series. The second filter circuit 52 has a coil 520 connected in series to the portion of the wiring between the coil 510 and the heater control unit 58. The coil 520 has a second core material with a relative permeability of 10 or more. With this structure, the filter circuit 500 in this embodiment can suppress the leakage of power supplied to the plasma to the heater control unit 58 and suppress power loss of the plasma.

[0071] Furthermore, in this embodiment, it is preferable that the capacitor 513 of the series resonant circuit 511 is a vacuum capacitor. This allows for the suppression of capacitance fluctuations in the series resonant circuit 511 due to heat generated from the heater 40.

[0072] Furthermore, in this embodiment, the second core material is a powder-pressed component, permalloy, or cobalt-based amorphous material. This reduces the inflow of power at the second frequency from the heater 40 to the heater control unit 58.

[0073] Alternatively, in this embodiment, the second filter circuit 52 may include a capacitor disposed between the wiring 522 between the coil 520 and the heater control unit 58 and ground. This reduces the inflow of power at the second frequency from the heater 40 to the heater control unit 58.

[0074] Furthermore, in this embodiment, the first frequency is, for example, 13MHz, the second frequency is, for example, 400kHz, and the third frequency is, for example, 50Hz. Additionally, in this embodiment, the stray capacitance of the wiring between the heater 40 and the first filter circuit 51, the wiring between the first filter circuit 51 and the second filter circuit 52, and the wiring between the second filter circuit 52 and the heater control unit 58 is, for example, 500pF or less. This reduces the loss of power supplied to the plasma.

[0075] [other]

[0076] Furthermore, the technology disclosed in this application is not limited to the above-described embodiments and can be modified extensively within its scope.

[0077] For example, in the above embodiment, RF power at a frequency of 13 MHz and RF power at a frequency of 400 kHz are used for plasma processing, but the disclosed technology is not limited to this. Alternatively, two RF powers at different frequencies of 4 MHz or higher and RF power at a frequency less than 4 MHz can be used for plasma processing. For example, RF power at 40 MHz, RF power at 13 MHz, and RF power at 400 kHz can be used for plasma processing.

[0078] For example, by Figure 9 The plasma processing device 1 shown is used to perform such plasma processing. Figure 9 This is a schematic cross-sectional view showing other examples of the plasma processing apparatus 1. Furthermore, in addition to the points described below, in... Figure 9 In, marked with Figure 1 The same reference numerals have the same structure. Figure 1 The structure is the same as described in the previous section, so the explanation is omitted.

[0079] The base station 12 is electrically connected to the first RF power supply 28, the second RF power supply 30, and the third RF power supply 29 via a matching unit 32 and a power supply rod 34. Figure 9 In the example, the first RF power supply 28 and the third RF power supply 29 primarily supply first-frequency RF power to the base 12 via the matching unit 32 and the power supply rod 34, which is conducive to plasma generation. Figure 9 In the example, the first frequency is a frequency above 4MHz. Figure 9 In the example, the first frequency of electricity contains electricity of multiple different frequencies. Figure 9In this example, the different frequencies of power are, for example, 13MHz power and, for example, 40MHz power. A first RF power source 28 supplies, for example, 13MHz RF power to the base station 12 via a matching unit 32 and a power supply rod 34. Additionally, a third RF power source 29 supplies, for example, 40MHz RF power to the base station 12 via the matching unit 32 and the power supply rod 34. The matching unit 32 achieves impedance matching between the first RF power source 28 and the plasma load, and between the third RF power source 29 and the plasma load.

[0080] The second RF power supply 30 primarily supplies high-frequency power of a second frequency to the base station 12 via the matching unit 32 and the power supply rod 34, which helps to attract ions to the substrate W on the base station 12. Figure 9 In the example, the second frequency is a frequency above 100Hz and less than 4MHz. Figure 9 In this example, the second frequency is, for example, 400 kHz. The matching unit 32 also achieves impedance matching between the second RF power supply 30 and the plasma load.

[0081] The power supply rod 34 is a generally cylindrical conductor. The upper end of the power supply rod 34 is connected to the center of the lower surface of the base 12, and the lower end of the power supply rod 34 is connected to the matching unit 32. Furthermore, a generally cylindrical cover 35 with an inner diameter larger than the outer diameter of the power supply rod 34 is disposed around the power supply rod 34. The upper end of the cover 35 is connected to an opening formed on the bottom surface of the chamber 10, and the lower end of the cover 35 is connected to the housing of the matching unit 32.

[0082] Figure 10 It means Figure 9 The diagram illustrates an example of a filter circuit 500 included in the plasma processing apparatus 1. The filter circuit 500 has multiple independent filter circuits 50-1 to 50-n. Furthermore, in addition to the points described below, in... Figure 10 In, marked with Figure 3 The same reference numerals have the same structure. Figure 3 The structure is the same as described in the previous section, so the explanation is omitted.

[0083] Each independent filter circuit 50 has a first filter circuit 51 for suppressing power at a first frequency and a second filter circuit 52 for suppressing power at a second frequency. The first filter circuit 51 has a coil 510 and a series resonant circuit 511. The series resonant circuit 511 includes a series resonant circuit 511a and a series resonant circuit 511b. The series resonant circuits 511a and 511b are examples of independent series resonant circuits.

[0084] A series resonant circuit 511a is connected between coil 510 and ground. The series resonant circuit 511a has a coil 512a and a capacitor 513a. Coil 512a and capacitor 513a are connected in series. In the series resonant circuit 511a, the constants of coil 512a and capacitor 513a are selected so that the resonant frequency of the series resonant circuit 511a is, for example, around 13 MHz (e.g., 13 MHz). Coil 512a, for example, is an air-core coil without a core, similar to coil 510. Figure 10 In the example, the inductance of coil 512a is, for example, 6μH. Additionally, the capacitance of capacitor 513a is, for example, 500pF or less. Figure 10 In this example, the capacitance of capacitor 513a is, for example, 25pF. Therefore, the resonant frequency of the series resonant circuit 511a is approximately 13MHz. RF power of, for example, 13MHz is suppressed by the coil 510 and the series resonant circuit 511a.

[0085] A series resonant circuit 511b is connected between coil 510 and ground. The series resonant circuit 511b has a coil 512b and a capacitor 513b. Coil 512b and capacitor 513b are connected in series. In the series resonant circuit 511b, the constants of coil 512b and capacitor 513b are selected so that the resonant frequency of the series resonant circuit 511b is, for example, around 40 MHz (e.g., 40 MHz). Coil 512b, for example, is an air-core coil without a core, similar to coil 510. Figure 10 In the example, the inductance of coil 512b is, for example, 2μH. Additionally, the capacitance of capacitor 513b is, for example, 500pF or less. Figure 10 In this example, the capacitance of capacitor 513a is, for example, 8pF. Therefore, the resonant frequency of the series resonant circuit 511b is approximately 40MHz. The coil 510 and the series resonant circuit 511b are used to suppress, for example, 40MHz of RF power.

[0086] In addition, Figure 9 In the example, the first frequency power above 4MHz includes, for example, two different frequencies of power, 13MHz and 40MHz, but the disclosed technology is not limited to this. As another example, the first frequency power may include three or more different frequencies of power. In this case, a series resonant circuit with a resonant frequency near the frequency of that power is provided for each frequency of power.

[0087] Furthermore, in the above embodiment, a series resonant circuit 511 is provided for each heater 40, but the disclosed technology is not limited to this. For example, [other methods may be used]. Figure 7 As shown, a series resonant circuit 511 is provided for multiple heaters 40. Figure 7This is a diagram showing other examples of filter circuit 500.

[0088] Figure 7 The filter circuit 500 illustrated herein includes multiple coils 510-1 to 510-n, multiple capacitors 515-1 to 515-n, a series resonant circuit 511, and multiple second filter circuits 52-1 to 52-n. Hereinafter, the multiple coils 510-1 to 510-n will be collectively referred to as coil 510, and the multiple capacitors 515-1 to 515-n will be collectively referred to as capacitor 515. Similarly, the multiple second filter circuits 52-1 to 52-n will be collectively referred to as second filter circuit 52.

[0089] The coil 510, capacitor 515, and second filter circuit 52 are each provided one for each heater 40. One end of the coil 510 is connected to the corresponding heater 40, and the other end of the coil 510 is connected to the series resonant circuit 511 via the corresponding capacitor 515. The other end of the coil 510 is connected to the heater control unit 58 via the corresponding second filter circuit 52. The capacitors 515, corresponding to each heater 40, are provided to suppress the flow of control power with a frequency less than 100Hz supplied from the heater control unit 58 to the other heaters 40. This allows for the independent supply of different amounts of control power to each heater 40. In this embodiment, the capacitance of each capacitor 515 is, for example, 2000pF. Therefore, for example, a 50Hz control power, the impedance of the capacitor 515 is approximately 1.6MΩ. Thus, the capacitor 515 can suppress the transmission of control power via the capacitor 515.

[0090] exist Figure 7 In this example, a coil 510 and a series resonant circuit 511 shared by them correspond to a first filter circuit 51 in the above embodiment. Furthermore, in Figure 7 In the example, a series resonant circuit 511 is shared by multiple heaters 40. However, it is possible to share a series resonant circuit 511 by two or more heaters 40, or to use multiple series resonant circuits 511. This allows the current flowing into a series resonant circuit 511 to be dispersed, thereby suppressing the heating of the series resonant circuit 511.

[0091] In the above embodiment, a series resonant circuit 511 is provided for each heater 40. Therefore, the total parasitic capacitance of the wiring of each individual filter circuit 50 exceeds 500 pF for the plasma generated within the chamber 10. Furthermore, as the number of heaters 40 increases, it becomes even more difficult to suppress the total parasitic capacitance of the wiring of each individual filter circuit 50 to below 500 pF. Consequently, the power loss of the plasma increases.

[0092] In response, Figure 7 In the filter circuit 500 illustrated, a series resonant circuit 511 is provided for multiple heaters 40. This makes it easy to suppress the total parasitic capacitance of the wiring of each individual filter circuit 50 to below 500 pF for plasma.

[0093] In addition, Figure 7 In this example, a series resonant circuit 511 is shared by multiple heaters 40. Other examples could include... Figure 8 As shown, a capacitor 513 is provided for multiple heaters 40 in common. Figure 8 This diagram illustrates another example of the filter circuit 500. Such a structure can also suppress power leakage from the plasma supply to the heater control unit 58 and suppress power loss from the plasma.

[0094] In addition, Figure 7 In the example, a coil 512 is provided in the series resonant circuit 511 shared by multiple heaters 40, but the disclosed technology is not limited to this. Figure 11 This is a diagram showing other examples of filter circuit 500.

[0095] exist Figure 11 In the illustrated filter circuit 500, a capacitor 513 and multiple coils 512-1 to 512-n are provided in the series resonant circuit 511. Hereinafter, these multiple coils 512-1 to 512-n will be collectively referred to as coil 512 without further distinction. Figure 11 In this example, each coil 512 is arranged such that one coil 510 is provided for each heater 40. Each coil 512 and coil 510 are connected in series. Furthermore, each coil 512 is connected to a capacitor 513 of the series resonant circuit 511 via a capacitor 515 provided for each heater 40. Figure 11 In the example, a coil 512 of a series resonant circuit 511 is provided for each heater 40, so that the current flowing into the coil of the series resonant circuit 511 can be dispersed, thereby suppressing the heating of the coil 512 of the series resonant circuit 511.

[0096] exist Figure 11 In the example, a coil 510, a coil 512 included in the series resonant circuit 511, and a capacitor 513 included in the series resonant circuit 511 correspond to a first filter circuit 51 in the above embodiment. Furthermore, in Figure 11 In the example, a capacitor 513 of a series resonant circuit 511 is provided for multiple heaters 40 to share. However, it is sufficient to provide a capacitor of a series resonant circuit 511 for two or more heaters 40 to share, or two or more capacitors 513 can be provided in the series resonant circuit 511.

[0097] In addition, Figure 11 In the example, a capacitor 515 is placed between the coil 512 and the capacitor 513 of the series resonant circuit 511, making it sometimes difficult to adjust the resonant frequency of the series resonant circuit 511. Therefore, it is also possible, for example... Figure 12 As shown, one end of each coil 512 is connected to coil 510 via capacitor 515. The other end of each coil 512 is connected to capacitor 513. The series resonant circuit 511 has capacitor 513 that is not like the multiple coils 512. Figure 11 By connecting it through other circuits, the resonant frequency of the series resonant circuit 511 can be easily adjusted.

[0098] Alternatively, for example Figure 13 As shown, a distribution unit 80 is provided between the plurality of heaters 40-1 to 40-n and the filter circuit 500. The distribution unit 80 independently supplies control power to each of the plurality of heaters 40-1 to 40-n. As a result, the filter circuit 500 can be miniaturized, thereby enabling the plasma processing apparatus 1 to be miniaturized.

[0099] Furthermore, in the above-described embodiment, control power from the heater control unit 58, which is an example of a power supply unit, is supplied to the heater 40, which is an example of a conductive member. However, the conductive member to which control power is supplied is not limited to this. For example, the power control unit may also supply power to conductive members other than the heater 40 provided in the plasma processing apparatus 1. Examples of conductive members other than the heater 40 include, for example, the base 12, which is supplied with power at a first frequency and power at a second frequency, the spray head 64, which supplies gas into the plasma processing apparatus 1, and the edge ring 36.

[0100] Furthermore, in the above embodiment, a plasma processing apparatus 1 using capacitively coupled plasma (CCP) as a plasma source was described as an example, but the plasma source is not limited to this. Examples of plasma sources other than capacitively coupled plasma include inductively coupled plasma (ICP).

[0101] Furthermore, in the above embodiment, power of a first frequency and power of a second frequency are supplied to the base 12, but the disclosed technology is not limited thereto. For example, at least either power of a first frequency or power of a second frequency may also be supplied to the shower head 64.

[0102] Furthermore, in the above embodiment, a plasma processing apparatus 1 for processing the substrate W using plasma generated by two types of electricity—a first frequency of 4 MHz or higher and a second frequency of 100 Hz or higher but less than 4 MHz—has been described as an example. However, the disclosed technology is not limited to this. The disclosed technology can also be applied to other methods, such as to a plasma processing apparatus 1 for processing the substrate W using plasma generated by one or more first frequencies and one or more second frequencies. For example, the disclosed technology can also be applied to a plasma processing apparatus 1 for processing the substrate W using plasma generated by using 40 MHz and 13 MHz as the first frequency and 400 kHz as the second frequency. In this case, each independent filter circuit 50 is provided with a series resonant circuit 511-1 with a resonant frequency set to 40 MHz and a series resonant circuit 511-2 with a resonant frequency set to 13 MHz.

[0103] In addition, in the above embodiment, the series resonant circuit 511 included in the first filter circuit 51 is disposed inside the cavity 10. However, as another option, the series resonant circuit 511 may be disposed outside the cavity 10, for example, disposed on the side of the second filter circuit 52 via a conduit 53. Alternatively, the series resonant circuit 511 may be disposed outside the cavity 10, for example, via a conduit 53, and connected to the second filter circuit 52 via a conduit 53.

[0104] Furthermore, it should be considered that all points in the disclosed embodiments are illustrative rather than limiting. In fact, the above embodiments can be implemented in various ways. In addition, the above embodiments can be omitted, substituted, or modified in various ways without departing from the appended claims and their spirit.

[0105] Explanation of reference numerals in the attached figures

[0106] S: Space; W: Substrate; 1: Plasma processing device; 2: Device body; 3: Control device; 10: Chamber; 12: Base; 14: Support; 16: Cylindrical support; 18: Exhaust path; 20: Exhaust port; 22: Exhaust pipe; 24: Exhaust device; 26: Gate valve; 28: First RF power supply; 29: Third RF power supply; 30: Second RF power supply; 32: Matching unit; 34: Power supply rod; 35: Cover; 36: Edge ring; 38: Electrostatic chuck; 380: Region; 40: Heater; 42: Dielectric; 44: Electrode; 45: DC power supply; 46: Switch; 500 50: Filter circuit; 51: Independent filter circuit; 51: First filter circuit; 510: Coil; 511: Series resonant circuit; 512: Coil; 513: Capacitor; 514: Wiring; 515: Capacitor; 52: Second filter circuit; 520: Coil; 521: Capacitor; 522: Wiring; 53: Piping; 58: Heater control unit; 60: Flow path; 62: Piping; 64: Spray head; 66: Electrode plate; 68: Support; 70: Diffusion chamber; 70a: Gas inlet; 72: Gas outlet; 74: Processed gas supply unit; 76: Piping; 80: Distribution unit.

Claims

1. A filter circuit disposed in a plasma processing apparatus for processing a substrate using plasma, the plasma being generated using power at a first frequency of 4 MHz or higher and power at a second frequency of 100 Hz or higher and less than 4 MHz, the filter circuit comprising: A first filter section is provided in the wiring between a conductive member disposed within the plasma processing apparatus and a power supply section for supplying control power to the conductive member, wherein the control power is power of a third frequency less than 100Hz or direct current power; and The second filter section is disposed in the portion of the wiring located between the first filter section and the power supply section. in, The first filter section includes: a first coil connected in series to the wiring, the first coil having no core or having a first core with a relative permeability of less than 10; and a series resonant circuit connected between the wiring and ground, the series resonant circuit having a coil and a capacitor connected in series. The second filter section has a second coil connected in series to the portion of the wiring between the first coil and the power supply section, and the second coil has a second core material with a relative permeability of 10 or more.

2. The filter circuit according to claim 1, characterized in that, The capacitor in the series resonant circuit is a vacuum capacitor.

3. The filter circuit according to claim 1 or 2, characterized in that, The second core material is a powder-pressed component, permalloy, or cobalt-based amorphous material.

4. The filter circuit according to claim 1 or 2, characterized in that, The second filter section has a capacitor disposed between the wiring portion located between the second coil and the power supply section.

5. The filter circuit according to claim 1 or 2, characterized in that, The conductive component is a heater used to control the temperature of the substrate.

6. The filter circuit according to claim 1 or 2, characterized in that, The stray capacitance of the portion of the wiring located between the conductive member and the first filter section, the portion of the wiring located between the first filter section and the second filter section, and the portion of the wiring located between the second filter section and the power supply section is 500pF or less.

7. The filter circuit according to claim 1 or 2, characterized in that, The plasma processing device contains a plurality of the aforementioned conductive components. The first filter section has a plurality of first coils and one or more of the series resonant circuits. Each of the first coils is provided in such a manner that one coil is provided for each of the aforementioned conductive components. Each of the aforementioned series resonant circuits is configured such that two or more of the first coils share a single series resonant circuit.

8. The filter circuit according to claim 1 or 2, characterized in that, The plasma processing device contains a plurality of the aforementioned conductive components. The first filter section has a plurality of first coils arranged such that one coil is provided for each of the aforementioned conductive members. The series resonant circuit has one or more capacitors and multiple coils arranged such that one is provided for each of the conductive components. The series resonant circuit has coils that are connected in series with each of the first coils. The capacitors in the series resonant circuit are arranged such that one or more of the first coils and one or more coils in the series resonant circuit share a single capacitor.

9. The filter circuit according to claim 1 or 2, characterized in that, The first frequency of electricity includes multiple electrical signals of different frequencies. The series resonant circuit includes multiple independent series resonant circuits, each with its own resonant frequency.

10. A filter circuit provided in a plasma processing apparatus for processing a substrate using plasma, the plasma being generated using power at a first frequency of 4 MHz or higher and power at a second frequency of 100 Hz or higher and less than 4 MHz, the filter circuit comprising: A first filter section is provided in the wiring between a plurality of conductive members disposed within the plasma processing apparatus and a power supply section for independently supplying control power to each of the conductive members, wherein the control power is power of a third frequency less than 100Hz or DC power; and The second filter section is disposed in the portion of the wiring located between the first filter section and the power supply section. in, The first filter section has: A plurality of first coils are provided in such a manner that one is provided for each of the conductive members. The first coils are connected in series to the wiring connected to their respective conductive members. Each first coil has no core material or has a first core material with a relative permeability of less than 10. And one or more capacitors, wherein the capacitors are arranged such that two or more of the first coils share one capacitor, and the capacitors are connected to ground at the portion of the wiring between the first coil and the second filter section. The second filter section has a plurality of second coils, which are arranged such that one is provided for each of the conductive members. The plurality of second coils are connected in series to the portion between the respective first coil of the wiring and the power supply section. The second coils have a second core material with a relative permeability of 10 or more.

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