Filter circuit and plasma processing apparatus

Abstract

To provide a filter circuit that suppresses leakage of power supplied to plasma to a power supply part and suppresses power loss of the plasma.SOLUTION: In a filter circuit 500 that is provided in a plasma processing apparatus which uses power of a first frequency being more than or equal to 4 MHz and power of a second frequency being more than or equal to 100 Hz and less than 4 MHz, a first filter part 51 is provided on a wiring line between heaters 40-1-n being conductive members in the plasma processing apparatus and a heater control section 58 being a power supply part which supplies power of a third frequency being less than 100 Hz to the conductive member or DC power. A second filter part 52 is provided on a wiring line between the first filter part and the power supply part. The first filter part comprises: a first coil 510 that is serially connected to the wiring line; and a serial resonant circuit 511 that is connected between the wiring line and ground. The second filter part comprises a second coil 520 that is serially connected to the wiring line between the first coil and the power supply part.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] Various aspects and embodiments of the present disclosure include a filter circuit and plasma processing equipment Regarding. [Background technology]

[0002] For example, Patent Document 1 below discloses a plasma processing apparatus including a first power supply 28, a second power supply 30, a heating wire 40, a heater power supply 58, and a filter 54. A first filter 84A of the filter 54 is composed of a first stage composed of an air-core coil AL1 and a capacitor AC1, and a second stage composed of a toroidal coil AL2 and a capacitor AC2. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-229565 Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides a filter circuit that can suppress leakage of power supplied to plasma to a power supply unit and suppress power loss in the plasma. [Means for solving the problem]

[0005] One aspect of the present disclosure provides a filter circuit provided in a plasma processing apparatus that performs processing using plasma 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 comprising a first filter unit and a second filter unit. The first filter unit is provided in a wiring between a conductive member provided in the plasma processing apparatus and a power supply unit that supplies power at a third frequency of less than 100 Hz or control power, which is DC power, to the conductive member. The second filter unit is provided in a wiring between the first filter unit and the power supply unit. The first filter unit includes a first coil connected in series to the wiring and having no core material or a first core material with a relative magnetic permeability less than 10, and a series resonant circuit connected between the wiring between the conductive member and the power supply unit and ground, the first coil including a coil and a capacitor connected in series. The second filter unit includes a second coil connected in series to the wiring between the first coil and the power supply unit and having a second core material with a relative magnetic permeability of 10 or higher. [Effects of the Invention]

[0006] According to various aspects and embodiments of the present disclosure, it is possible to suppress leakage of power supplied to plasma to the power supply unit and suppress power loss in plasma. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic cross-sectional view illustrating an example of a plasma processing apparatus according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a top view showing an example of the distribution of regions of an electrostatic chuck. [Figure 3] FIG. 3 is a diagram illustrating an example of a filter circuit according to an embodiment of the present disclosure. [Figure 4] FIG. 4 is a diagram showing an example of the impedance of a wiring relative to the parasitic capacitance of the wiring at a frequency of 400 kHz. [Figure 5] FIG. 5 is a diagram showing an example of the magnitude of the voltage generated on the surface of the substrate relative to the magnitude of the 13 MHz RF power. [Figure 6] FIG. 6 is a diagram showing an example of the magnitude of the voltage generated on the surface of the substrate relative to the magnitude of the 400 kHz RF power. [Figure 7] FIG. 7 is a diagram illustrating another example of a filter circuit. [Figure 8] FIG. 8 is a diagram illustrating another example of a filter circuit. [Figure 9] FIG. 9 is a schematic cross-sectional view showing another example of the plasma processing apparatus. [Figure 10] FIG. 10 is a diagram showing an example of a filter circuit included in the plasma processing apparatus shown in FIG. [Figure 11] FIG. 11 is a diagram illustrating another example of a filter circuit. [Figure 12] FIG. 12 is a diagram illustrating another example of a filter circuit. [Figure 13] FIG. 13 is a diagram illustrating another example of a filter circuit. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments of the disclosed filter circuit will be described in detail with reference to the drawings. Note that the disclosed filter circuit is not limited to the following embodiments.

[0009] Some apparatuses for processing substrates using plasma are equipped with a conductive member such as a heater for adjusting the temperature of the substrate. A filter circuit is provided in the wiring between the conductive member and a power supply unit to prevent RF power used to generate the plasma from leaking into the power supply unit, such as a heater control circuit, via the conductive member. Furthermore, when power of a first frequency and power of a second frequency are supplied to the plasma, the filter circuit must prevent both the power of the first frequency and the power of the second frequency from leaking into the power supply unit, such as a heater control circuit, via the conductive member.

[0010] However, if the impedance of the filter circuit is low at the first frequency and the second frequency, the power of the first frequency and the power of the second frequency supplied to the plasma will decrease, causing a power loss in the plasma.

[0011] Therefore, the present disclosure provides a technique that can suppress leakage of power supplied to plasma to the power supply unit and can also suppress power loss in plasma.

[0012] [Configuration of plasma processing apparatus 1] 1 is a schematic cross-sectional view showing an example of a plasma processing apparatus 1 according to an embodiment of the present disclosure. The plasma processing apparatus 1 according to this embodiment is an apparatus for processing a substrate W using capacitively coupled plasma. The plasma processing apparatus 1 includes an apparatus main body 2 and a control apparatus 3.

[0013] The apparatus main body 2 has a substantially cylindrical chamber 10 made of, for example, aluminum or stainless steel. The chamber 10 is safety grounded. A substantially disk-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 that extends vertically upward from the bottom of the chamber 10. The support 14 is made of an insulating material such as ceramics. Therefore, the support 14 is electrically insulated from the chamber 10.

[0014] An electrically conductive cylindrical support 16 is provided on the outer periphery of the support 14, extending vertically upward from the bottom of the chamber 10 along the outer periphery of the support 14. An annular exhaust path 18 is formed between the cylindrical support 16 and the inner wall of the chamber 10. An exhaust port 20 is provided at the bottom of the exhaust path 18. An exhaust device 24 having a turbomolecular pump or the like is connected to the exhaust port 20 via an exhaust pipe 22. The exhaust device 24 depressurizes the processing space within the chamber 10 to a desired vacuum level. An opening is formed in the sidewall of the chamber 10 for loading and unloading the substrate W, and this opening is opened and closed by a gate valve 26.

[0015] A first RF (Radio Frequency) power supply 28 and a second RF power supply 30 are electrically connected to the base 12 via a matching unit 32 and a power feed rod 34. The first RF power supply 28 supplies RF power of a first frequency, which mainly contributes to plasma generation, to the base 12 via the matching unit 32 and the power feed rod 34. In this embodiment, the first frequency is 4 MHz or higher. In this embodiment, the first frequency is, for example, 13 MHz. The matching unit 32 matches impedance between the first RF power supply 28 and the plasma load.

[0016] The second RF power supply 30 supplies high-frequency power of a second frequency, which mainly contributes to attracting ions to the substrate W on the base 12, to the base 12 via the matching unit 32 and the power feed rod 34. In this embodiment, the second frequency is equal to or greater than 100 Hz and less than 4 MHz. In this embodiment, the second frequency is, for example, 400 kmhz. The matching unit 32 further matches impedance between the second RF power supply 30 and the plasma load.

[0017] The power feed rod 34 is a substantially cylindrical conductor. The upper end of the power feed rod 34 is connected to the center of the lower surface of the base 12, and the lower end of the power feed rod 34 is connected to the matching unit 32. A substantially cylindrical cover 35 having an inner diameter larger than the outer diameter of the power feed rod 34 is disposed around the power feed rod 34. The upper end of the cover 35 is connected to an opening formed in 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.

[0018] An edge ring 36 and an electrostatic chuck 38 are disposed on the base 12. The edge ring 36 is also called a focus ring. A substrate W to be processed is disposed on the upper surface of the electrostatic chuck 38. The edge ring 36 has a substantially annular outer shape, and the electrostatic chuck 38 has a substantially disk-shaped outer shape. The edge ring 36 is disposed around the electrostatic chuck 38 so as to surround the electrostatic chuck 38 and the substrate W on the electrostatic chuck 38. The edge ring 36 is formed of, for example, silicon (Si), silicon carbide (SiC), carbon (C), silicon dioxide (SiO2), or the like.

[0019] The electrostatic chuck 38 has multiple heaters 40, a dielectric 42, and an electrode 44. The heater 40 is an example of a conductive member. The multiple heaters 40 and the electrode 44 are sealed in the dielectric 42. The electrode 44 is electrically connected to a DC power supply 45 located outside the chamber 10 via a switch 46. The electrode 44 attracts and holds the substrate W on the upper surface of the electrostatic chuck 38 by Coulomb force generated by a DC voltage applied from the DC power supply 45. The wiring between the switch 46 and the electrode 44 is covered with an insulator, passes through the power supply rod 34, penetrates the base 12 from below, and is connected to the electrode 44 of the electrostatic chuck 38.

[0020] Each heater 40 generates heat in response to control power supplied from heater control unit 58. In this embodiment, the control power supplied from heater control unit 58 is AC power with a frequency of 50 Hz. Note that the control power supplied from heater control unit 58 to each heater 40 may be AC ​​power or DC power with a third frequency less than 100 Hz.

[0021] The upper surface of the electrostatic chuck 38 has a plurality of regions 380, as shown in Fig. 2, for example. Fig. 2 is a top view showing an example of the distribution of the regions of the electrostatic chuck 38. In this embodiment, the plurality of regions 380 are concentrically arranged around the central axis X of the electrostatic chuck 38. Each heater 40 (heater 40-1, heater 40-2, ...) is arranged in each of the regions 380.

[0022] Continuing the explanation, returning to FIG. 1 , a heater control unit 58 is connected to each heater 40 via a filter circuit 500 including a first filter circuit 51 and a second filter circuit 52. The heater control unit 58 controls the amount of heat generated by each heater 40 by controlling the power supplied to each heater 40 via the filter circuit 500. The heater control unit is an example of a power supply unit. Details of the filter circuit 500 will be described later. In this embodiment, for example, n regions (n ​​is an integer of 2 or more) are provided on the upper surface of the electrostatic chuck 38, and n heaters 40 are arranged on the electrostatic chuck 38. Hereinafter, when distinguishing between the heaters 40, they will be referred to as heater 40-1, heater 40-2, ..., heater 40-n, etc.

[0023] An annular flow path 60 is provided inside the base 12, and a coolant is circulated and supplied through the flow path 60 from a chiller unit (not shown). The base 12 is cooled by the coolant circulating through 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, the base 12 and the electrostatic chuck 38 are provided with piping 62 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 through the piping 62.

[0024] A shower head 64 is provided on the ceiling of the chamber 10 at a position facing the base 12. The shower head 64 also functions as an upper electrode, which is an opposing electrode to the base 12, which functions as a lower electrode. A space S between the shower head 64 and the base 12 serves as a plasma generation space. The shower head 64 has an electrode plate 66 facing the base 12 and a support 68 that detachably supports the electrode plate 66 from above. The electrode plate 66 is made of, for example, Si or SiC. The support 68 is made of, for example, anodized aluminum.

[0025] A diffusion chamber 70 is formed inside the support 68. A plurality of gas discharge ports 72 are formed in the electrode plate 66 and the support 68, penetrating from the diffusion chamber 70 toward the base 12. A gas inlet 70a communicating with the diffusion chamber 70 is provided in the upper part of the support 68. A process gas supply unit 74 is connected to the gas inlet 70a via a pipe 76. The process gas supply unit 74 is provided with gas supply sources for supplying different types of gas. A flow controller, a valve, etc. are connected to each gas supply source. Then, each type of gas, the flow rate of which is controlled by the flow controller, is supplied into the space S via the pipe 76.

[0026] Each part of the apparatus main body 2 is controlled by a control device 3 including, for example, a memory, a processor, and an input / output interface. The memory stores a control program, a processing recipe, etc. The processor reads and executes the control program from the memory, and controls each part of the apparatus main body 2 via the input / output interface based on the recipe, etc. stored in the memory. In this way, the plasma processing apparatus 1 performs processing such as etching using plasma on the substrate W.

[0027] [Configuration of filter circuit 500] 3 is a diagram illustrating an example of a filter circuit 500 according to an embodiment of the present disclosure. The filter circuit 500 has a plurality of individual filter circuits 50-1 to 50-n. Note that, hereinafter, the plurality of individual filter circuits 50-1 to 50-n will be collectively referred to as individual filter circuits 50 without distinguishing between them.

[0028] Each individual filter circuit 50 includes a first filter circuit 51 that suppresses power of a first frequency and a second filter circuit 52 that suppresses power of a second frequency. The first filter circuit 51 is provided on a wiring between the heater 40 provided in the plasma processing apparatus 1 and a heater control unit 58 that supplies control power to the heater 40. The first filter circuit 51 is an example of a first filter unit. The first filter circuit 51 includes a coil 510 and a series resonant circuit 511. The coil 510 is an air-core coil that does not have a core material (i.e., the core material is air). This allows heat generation of the coil 510 to be suppressed. The coil 510 is an example of a first coil. In this embodiment, the inductance of the coil 510 is, for example, 50 μH. The coil 510 may include a core material with a magnetic permeability of less than 10, such as a resin material such as PTFE (polytetrafluoroethylene). The core material with a magnetic permeability of less than 10 is an example of a first core material.

[0029] The 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, the constants of the coil 512 and the capacitor 513 are selected so that the resonant frequency of the series resonant circuit 511 is near a first frequency (for example, the first frequency). The coil 512 is, for example, an air-core coil that does not have a core material, similar to the coil 510. In this embodiment, the inductance of the coil 512 is, for example, 6 μH. The capacitance of the capacitor 513 is, for example, 500 pF or less, and in this embodiment, the capacitance of the capacitor 513 is, for example, 25 pF. As a result, the resonant frequency of the series resonant circuit 511 is approximately 13 MHz.

[0030] Since the first filter circuit 51 suppresses the power of the first frequency, which is higher than the second frequency, it is preferable to make the wiring between the heater 40 and the first filter circuit 51 as short as possible. This makes it less susceptible to the effects of stray capacitance and inductance of the wiring and also suppresses RF power leakage. It is preferable that the capacitor 513 is, for example, a vacuum capacitor. This makes it possible to minimize the temperature-dependent dielectric constant and to minimize the resistance component of the capacitor 513, thereby minimizing heat generation due to the RF power current.

[0031] A node between the coil 510 and the series resonant circuit 511 is connected to the second filter circuit 52 via a wiring 514. The wiring 514 between the first filter circuit 51 and the second filter circuit 52 is shielded by a metal pipe 53.

[0032] The second filter circuit 52 is provided on the wiring between the first filter circuit 51 and the heater control unit 58. The second filter circuit 52 is an example of a second filter unit. The second filter circuit 52 has a coil 520 and a capacitor 521. The coil 520 is a cored coil having a core material with a magnetic permeability of 10 or more. The coil 520 is an example of a second coil. In this embodiment, the inductance of the coil 510 is, for example, 10 mH. Examples of core materials with a magnetic permeability of 10 or more include dust material, permalloy, and cobalt-based amorphous alloys.

[0033] The capacitor 521 is connected between the coil 520 and ground. The second filter circuit 52 suppresses power at a second frequency that is lower than the first frequency, and therefore can be provided at a position farther from the heater 40 than the first filter circuit 51. Therefore, the capacitor 521 can be a ceramic capacitor or the like that is less susceptible to heat from the heater 40 and is less expensive than a vacuum capacitor. In this embodiment, the capacitance of the capacitor 521 is, for example, 2000 pF. Note that if a capacitor with a capacitance similar to that of the capacitor 521 is provided at the output terminal of the heater control unit 58 connected to the wiring 522, the capacitor 521 does not need to be provided in the second filter circuit 52.

[0034] A node between the coil 520 and the capacitor 521 is connected to the heater control unit 58 via a wiring 522. In this embodiment, the parasitic capacitances of the wiring between the heater 40 and the first filter circuit 51, the wiring 514 between the first filter circuit 51 and the second filter circuit 52, and the wiring 522 between the second filter circuit 52 and the heater control unit 58 are adjusted to be 500 pF or less. For example, the parasitic capacitance between the wiring and the ground is adjusted to be 500 pF or less by increasing the distance between the wiring and the ground by inserting a spacer such as a resin between the wiring and the ground.

[0035] [Parasitic capacitance of wiring] 4 is a diagram showing an example of the impedance of a wiring relative to the parasitic capacitance of the wiring at a frequency of 400 kHz. At 400 kHz, the impedance of the plasma is approximately 800 Ω. Therefore, when the impedance of the wiring falls below 800 Ω, more of the supplied power flows into the filter circuit 500 than into the plasma, resulting in increased power loss.

[0036] When the parasitic capacitance of a wiring is 500 pF, the impedance of the wiring is approximately 800 Ω, as shown in Figure 4. Also, as shown in Figure 4, the lower the parasitic capacitance of the wiring, the higher the impedance of the wiring. Therefore, in order to reduce power loss, it is preferable that the parasitic capacitance of the wiring be 500 pF or less.

[0037] [RF current flow] Since the coil 510 has a high impedance of, for example, about 4 kΩ for a frequency of, for example, 13 MHz (first frequency), the RF current flowing from the plasma to the first filter circuit 51 via the heater 40 is kept low. In addition, since the resonant frequency of the series resonant circuit 511 is set to a frequency close to 13 MHz (for example, 13 MHz), the RF current of the 13 MHz frequency that has passed through the coil 510 flows to the ground via the series resonant circuit 511, and hardly flows into the second filter circuit 52.

[0038] Furthermore, when the plasma voltage at 13 MHz is 5 kVpp, the plasma voltage leaking to first filter circuit 51 via heater 40 is divided by coil 510 of approximately 4 kΩ and series resonant circuit 511 of less than 1 Ω, and is suppressed to 100 Vpp or less. The plasma voltage suppressed to 100 Vpp or less by first filter circuit 51 is further divided by coil 520 and capacitor 521 of second filter circuit 52, and is suppressed to less than 40 Vpp. If the plasma voltage is less than 40 Vpp, it is within the guaranteed operation range of heater control unit 58, and therefore the plasma voltage has almost no effect on the operation of heater control unit 58.

[0039] Fig. 5 is a diagram showing an example of the magnitude of the voltage generated on the surface of the substrate W relative to the magnitude of the 13 MHz RF power. Fig. 5 also shows, as a comparative example, the voltage when the filter circuit 500 is not provided. For example, as shown in Fig. 5, even when the filter circuit 500 of this embodiment is used, the magnitude of the voltage generated on the surface of the substrate W is almost the same as in the comparative example in which the filter circuit 500 is not used.

[0040] On the other hand, coil 510 has an impedance of, for example, about 900Ω at a frequency (second frequency) of 400 kHz. The impedance of coil 510 is equal to or greater than the impedance of 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 plasma at 400 kHz. Therefore, although the RF current at a frequency of 400 kHz flows more into filter circuit 500 than the RF current at a frequency of 13 MHz, a sufficient current also flows into the plasma.

[0041] Furthermore, when the plasma voltage at 400 kHz is 5 kVpp, the plasma voltage leaking to first filter circuit 51 via heater 40 is divided by coil 510 of approximately 100 Ω and series resonant circuit 511 of approximately 1 kΩ, and is suppressed to 4.5 kVpp or less. The plasma voltage suppressed to 4.5 Vpp or less by first filter circuit 51 is further divided by coil 520 and capacitor 521 of second filter circuit 52, and is suppressed to less than 40 Vpp. If the plasma voltage is less than 40 Vpp, it is within the guaranteed operation range of heater control unit 58, and therefore the plasma voltage has almost no effect on the operation of heater control unit 58.

[0042] 6 is a diagram showing an example of the magnitude of the voltage generated on the surface of the substrate W relative to the magnitude of the 400 kHz RF power. In FIG. 6, the voltage when the filter circuit 500 is not provided (i.e., equivalent to the case where the impedance of the filter circuit is infinite) is shown as a comparative example. For example, as shown in FIG. 6, even when the filter circuit 500 of this embodiment is used, the magnitude of the voltage generated on the surface of the substrate W is almost the same as in the comparative example where the filter circuit 500 is not used. Therefore, when the filter circuit 500 of this embodiment is used, the plasma power flowing into the heater control unit 58 can be suppressed while maintaining the performance of the plasma processing on the substrate W.

[0043] In this embodiment, power of the first frequency and power of the second frequency are supplied to the base 12, and control power from the heater control unit 58 is supplied to the heater 40 provided near the base 12. Therefore, if the filter circuit 500 is not able to sufficiently suppress leakage of the power of the first frequency and power of the second frequency to the heater control unit 58, most of the power of the first frequency and power of the second frequency supplied to the base 12 will leak to the heater control unit 58. This will result in a large power loss in the plasma. In contrast, the filter circuit 500 of this embodiment can sufficiently suppress leakage of the power of the first frequency and power of the second frequency to the heater control unit 58. Therefore, the filter circuit 500 of this embodiment is particularly effective in a plasma processing apparatus 1 configured so that power of the first frequency and power of the second frequency are supplied to the base 12 provided near the heater 40.

[0044] Here, the filter circuit 500 is required to have three functions. (1) The loss of power supplied to the plasma is reduced by providing the filter circuit 500. If the impedance of the filter circuit 500 is low, the current associated with the power of the first frequency and the power of the second frequency supplied to the base 12 will flow not only into the plasma but also into the filter circuit 500 via the heater 40. This will lead to a loss of the power of the first frequency and the power of the second frequency. (2) The first frequency power and the second frequency power must not flow into the heater control unit 58 connected to the filter circuit 500. A large voltage of, for example, around 5 kVpp may be applied to the base 12 to which the first frequency power and the second frequency power are supplied. On the other hand, the heater control unit 58 may malfunction or be damaged if a voltage of, for example, several tens of volts or more is applied. The 5 kVpp voltage leaking from the base 12 side must be reduced to several tens of volts on the heater control unit 58 side by the individual filter circuit 50. (3) As described above in (1) and (2), the filter circuit 500 has the function of sufficiently suppressing the current and voltage flowing in from the heater 40. On the other hand, the current supplied from the heater control unit 58 is required to be transmitted with minimal loss.

[0045] Conventional filter circuits are either compatible with only frequencies above 10 MHz or compatible with only frequencies below 10 MHz, but the filter circuit 500 of this embodiment can simultaneously support both frequencies.

[0046] One embodiment has been described above. As described above, the filter circuit 500 in this embodiment is provided in a plasma processing apparatus 1 that performs processing using plasma generated using power with a first frequency of 4 MHz or higher and power with a second frequency of 100 Hz or higher but lower 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 wiring between a heater 40 provided in the plasma processing apparatus 1 and a heater control unit 58 that supplies control power, which is power with a third frequency of lower than 100 Hz or DC power, to the heater 40. The second filter circuit 52 is provided in wiring between the first filter circuit 51 and the heater control unit 58. The first filter circuit 51 is connected in series to the wiring and has no core material or a first core material with a relative magnetic permeability of less than 10, and includes a series resonant circuit 511 connected between the wiring between the heater 40 and the heater control unit 58 and ground, and includes a coil 512 and a capacitor 513 connected in series. The second filter circuit 52 is connected in series to the wiring between the coil 510 and the heater control unit 58 and includes a coil 520 having a second core material with a relative magnetic permeability of 10 or more. With this configuration, the filter circuit 500 in this embodiment can suppress leakage of power supplied to the plasma to the heater control unit 58 and suppress power loss in the plasma.

[0047] In this embodiment, the capacitor 513 of the series resonant circuit 511 is preferably a vacuum capacitor, which can suppress fluctuations in the capacitance of the series resonant circuit 511 due to heat generated by the heater 40.

[0048] In this embodiment, the second core material is a dust material, permalloy, or cobalt-based amorphous material, which can reduce the inflow of power at the second frequency from the heater 40 to the heater control unit 58.

[0049] In this embodiment, the second filter circuit 52 may also include a capacitor provided between the ground and the wiring 522 between the coil 520 and the heater control unit 58. This makes it possible to reduce the inflow of power of the second frequency from the heater 40 to the heater control unit 58.

[0050] In this embodiment, the first frequency is, for example, 13 MHz, the second frequency is, for example, 400 kHz, and the third frequency is, for example, 50 Hz. 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, 500 pF or less. This reduces the loss of power supplied to the plasma.

[0051] [others] The technology disclosed in this application is not limited to the above-described embodiment, and various modifications are possible within the scope of the gist thereof.

[0052] For example, in the above-described embodiment, plasma processing is performed using RF power with a frequency of 13 MHz and RF power with a frequency of 400 kHz, but the disclosed technology is not limited to this. As another embodiment, plasma processing may be performed using two RF powers with different frequencies of 4 MHz or higher and RF power with a frequency less than 4 MHz. For example, plasma processing may be performed using RF power of 40 MHz, RF power of 13 MHz, and RF power of 400 kHz.

[0053] Such plasma processing is performed, for example, by a plasma processing apparatus 1 as shown in Fig. 9. Fig. 9 is a schematic cross-sectional view showing another example of the plasma processing apparatus 1. Except for the points described below, components in Fig. 9 that are given the same reference numerals as those in Fig. 1 are the same as the components described in Fig. 1, and therefore description thereof will be omitted.

[0054] The base 12 is electrically connected to a first RF power supply 28, a second RF power supply 30, and a third RF power supply 29 via a matching unit 32 and a power feed rod 34. In the example of FIG. 9, the first RF power supply 28 and the third RF power supply 29 supply RF power of a first frequency, which mainly contributes to plasma generation, to the base 12 via the matching unit 32 and the power feed rod 34. In the example of FIG. 9, the first frequency is 4 MHz or higher. In the example of FIG. 9, the power of the first frequency includes power of multiple different frequencies. In the example of FIG. 9, the power of multiple different frequencies is, for example, 13 MHz power and, for example, 40 MHz power. The first RF power supply 28 supplies RF power of, for example, 13 MHz to the base 12 via the matching unit 32 and the power feed rod 34. The third RF power supply 29 supplies RF power of, for example, 40 MHz to the base 12 via the matching unit 32 and the power feed rod 34. The matching unit 32 matches the impedance between the first RF power supply 28 and the third RF power supply 29 and the plasma load.

[0055] The second RF power supply 30 supplies high-frequency power of a second frequency, which mainly contributes to attracting ions to the substrate W on the base 12, to the base 12 via the matching unit 32 and the power feed rod 34. In the example of Fig. 9, the second frequency is equal to or greater than 100 Hz and less than 4 MHz. In the example of Fig. 9, the second frequency is, for example, 400 kmhz. The matching unit 32 further matches impedance between the second RF power supply 30 and the plasma load.

[0056] The power feed rod 34 is a substantially cylindrical conductor. The upper end of the power feed rod 34 is connected to the center of the lower surface of the base 12, and the lower end of the power feed rod 34 is connected to the matching unit 32. A substantially cylindrical cover 35 having an inner diameter larger than the outer diameter of the power feed rod 34 is disposed around the power feed rod 34. The upper end of the cover 35 is connected to an opening formed in 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.

[0057] Fig. 10 is a diagram showing an example of a filter circuit 500 included in the plasma processing apparatus 1 illustrated in Fig. 9. The filter circuit 500 includes a plurality of individual filter circuits 50-1 to 50-n. Note that, except for the points described below, components in Fig. 10 that are assigned the same reference numerals as those in Fig. 3 are similar to the components described in Fig. 3, and therefore description thereof will be omitted.

[0058] Each individual filter circuit 50 has a first filter circuit 51 that suppresses power of a first frequency and a second filter circuit 52 that suppresses power of 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 circuit 511a and the series resonant circuit 511b are examples of individual series resonant circuits.

[0059] The series resonant circuit 511a is connected between the coil 510 and ground. The series resonant circuit 511a includes a coil 512a and a capacitor 513a. The coil 512a and the capacitor 513a are connected in series. In the series resonant circuit 511a, the constants of the coil 512a and the 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). The coil 512a is, for example, an air-core coil without a core material, similar to the coil 510. In the example of FIG. 10, the inductance of the coil 512a is, for example, 6 μH. The capacitance of the capacitor 513a is, for example, 500 pF or less, and in the example of FIG. 10, the capacitance of the capacitor 513a is, for example, 25 pF. As a result, the resonant frequency of the series resonant circuit 511a is approximately 13 MHz. The coil 510 and the series resonant circuit 511a suppress RF power at, for example, 13 MHz.

[0060] The series resonant circuit 511b is connected between the coil 510 and ground. The series resonant circuit 511b includes a coil 512b and a capacitor 513b. The coil 512b and the capacitor 513ba are connected in series. In the series resonant circuit 511b, the constants of the coil 512b and the 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). The coil 512b is, for example, an air-core coil without a core material, similar to the coil 510. In the example of FIG. 10, the inductance of the coil 512b is, for example, 2 μH. The capacitance of the capacitor 513b is, for example, 500 pF or less, and in the example of FIG. 10, the capacitance of the capacitor 513a is, for example, 8 pF. As a result, the resonant frequency of the series resonant circuit 511b is approximately 40 MHz. The coil 510 and the series resonant circuit 511b suppress RF power at, for example, 40 MHz.

[0061] 9, the power of the first frequency of 4 MHz or higher includes power of two different frequencies, for example, 13 MHz and 40 MHz, but the disclosed technology is not limited to this. As another example, the power of the first frequency may include power of three or more different frequencies. In this case, for each power frequency, one series resonant circuit is provided, the resonant frequency of which is a frequency near the frequency of that power.

[0062] In the above embodiment, one series resonant circuit 511 is provided for each heater 40, but the disclosed technology is not limited to this. For example, as shown in Fig. 7, one series resonant circuit 511 may be provided in common for a plurality of heaters 40. Fig. 7 is a diagram showing another example of a filter circuit 500.

[0063] 7 includes a plurality of coils 510-1 to 510-n, a plurality of capacitors 515-1 to 515-n, a series resonant circuit 511, and a plurality of second filter circuits 52-1 to 52-n. Hereinafter, the plurality of coils 510-1 to 510-n will be referred to collectively without distinction as coils 510, and the plurality of capacitors 515-1 to 515-n will be referred to collectively without distinction as capacitors 515. Furthermore, below, the plurality of second filter circuits 52-1 to 52-n will be referred to collectively without distinction as second filter circuits 52.

[0064] Each heater 40 is provided with one coil 510, one capacitor 515, and one second filter circuit 52. 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 capacitor 515 provided for each heater 40 is provided to prevent control power with a frequency of less than 100 Hz, supplied from the heater control unit 58 to each heater 40, from flowing into other heaters 40. This makes it possible to supply different amounts of control power independently to each heater 40. In this embodiment, the capacitance of each capacitor 515 is, for example, 2000 pF. Therefore, for example, with respect to 50 Hz control power, the impedance of the capacitor 515 is approximately 1.6 MΩ. Therefore, the capacitor 515 can suppress the transmission of control power through the capacitor 515.

[0065] 7, one series resonant circuit 511 provided in common with one coil 510 corresponds to one first filter circuit 51 in the above-described embodiment. Note that in the example of Fig. 7, one series resonant circuit 511 is provided in common with respect to a plurality of heaters 40, but a plurality of series resonant circuits 511 may be provided as long as one series resonant circuit 511 is provided in common with respect to two or more heaters 40. This makes it possible to distribute the current flowing into one series resonant circuit 511 and suppress heat generation in the series resonant circuit 511.

[0066] In the above embodiment, one series resonant circuit 511 is provided for each individual filter circuit 50. Therefore, the total parasitic capacitance of the wiring of each individual filter circuit 50 may exceed 500 pF for the plasma generated in the chamber 10. Furthermore, as the number of heaters 40 increases, it becomes even more difficult to keep the total parasitic capacitance of the wiring of each individual filter circuit 50 at 500 pF or less. This may result in increased power loss in the plasma.

[0067] 7, a series resonant circuit 511 is provided in common for multiple heaters 40. This makes it easy to keep the total parasitic capacitance of the wiring of each individual filter circuit 50 to 500 pF or less with respect to plasma.

[0068] 7, one series resonant circuit 511 is provided in common for the plurality of heaters 40, but as another example, one capacitor 513 may be provided in common for the plurality of heaters 40, as shown in FIG. 8. FIG. 8 is a diagram showing another example of the filter circuit 500. Even with this configuration, it is possible to suppress leakage of power supplied to the plasma to the heater control unit 58 and suppress power loss in the plasma.

[0069] 7, the series resonant circuit 511 provided in common to the plurality of heaters 40 is provided with one coil 512, but the disclosed technology is not limited to this. FIG. 11 is a diagram showing another example of the filter circuit 500.

[0070] In the filter circuit 500 illustrated in FIG. 11, a series resonant circuit 511 is provided with a plurality of coils 512-1 to 512-n and a capacitor 513. Hereinafter, the plurality of coils 512-1 to 512-n will be collectively referred to as coils 512 without distinction. In the example of FIG. 11, each coil 512 is provided for each heater 40 and each coil 510. Each coil 512 is connected in series to the coil 510. Each coil 512 is also connected to a capacitor 513 of the series resonant circuit 511 via a capacitor 515 provided for each heater 40. In the example of FIG. 11, each coil 512 of the series resonant circuit 511 is provided for each heater 40. Therefore, the current flowing into the coil of the series resonant circuit 511 can be dispersed, and heat generation of the coil 512 of the series resonant circuit 511 can be suppressed.

[0071] 11, one coil 510, one coil 512 included in the series resonant circuit 511, and a capacitor 513 in the series resonant circuit 511 correspond to one first filter circuit 51 in the above-described embodiment. Note that in the example of Fig. 11, one capacitor 513 in the series resonant circuit 511 is provided in common to a plurality of heaters 40. However, two or more capacitors 513 may be provided in the series resonant circuit 511 as long as one capacitor in the series resonant circuit 511 is provided in common to two or more heaters 40.

[0072] 11, since the capacitor 515 is provided between the coil 512 and the capacitor 513 of the series resonant circuit 511, it may be difficult to adjust the resonant frequency of the series resonant circuit 511. Therefore, for example, as shown in FIG. 12, one end of each coil 512 may be connected to the coil 510 via the capacitor 515. The other end of each coil 512 is connected to the capacitor 513. As shown in FIG. 11, the multiple coils 512 and the capacitor 513 included in the series resonant circuit 511 are connected without any other circuit between them, so that the resonant frequency of the series resonant circuit 511 can be easily adjusted.

[0073] 13, a distributor 80 may be provided between the heaters 40-1 to 40-n and the filter circuit 500. The distributor 80 supplies control power to each of the heaters 40-1 to 40-n individually. This allows the filter circuit 500 to be miniaturized, and the plasma processing apparatus 1 to be miniaturized.

[0074] In the above embodiment, the heater control unit 58, which is an example of a power supply unit, supplies control power to the heater 40, which is an example of a conductive member. However, the conductive member to which the control power is supplied is not limited to this. For example, the power control unit may supply power to a conductive member other than the heater 40 provided in the plasma processing apparatus 1. Examples of conductive members other than the heater 40 include the base 12 to which power of the first frequency and power of the second frequency are supplied, the shower head 64 that supplies gas into the plasma processing apparatus 1, the edge ring 36, etc.

[0075] In the above embodiment, the plasma processing apparatus 1 uses a capacitively coupled plasma (CCP) as a plasma source, but the plasma source is not limited to this. Examples of plasma sources other than the capacitively coupled plasma include an inductively coupled plasma (ICP).

[0076] In the above-described embodiment, the power of the first frequency and the power of the second frequency are supplied to the base 12, but the disclosed technology is not limited to this. For example, at least one of the power of the first frequency and the power of the second frequency may be supplied to the shower head 64.

[0077] In the above-described embodiment, the plasma processing apparatus 1 processes the substrate W with plasma generated using two types of power: power with a first frequency of 4 MHz or more and power with a second frequency of 100 Hz or more and less than 4 MHz. However, the disclosed technology is not limited to this. As another embodiment, the disclosed technology can be applied to a plasma processing apparatus 1 that processes the substrate W with plasma generated using power with one or more first frequencies and power with one or more second frequencies. For example, the disclosed technology can be applied to a plasma processing apparatus 1 that processes the substrate W with plasma generated using powers of 40 MHz and 13 MHz as the first frequency powers and power of 400 kHz as the second frequency power. In this case, each individual filter circuit 50 is provided with a series resonant circuit 511-1 having a resonant frequency set to 40 MHz and a series resonant circuit 511-2 having a resonant frequency set to 13 MHz.

[0078] In the above embodiment, the series resonant circuit 511 included in the first filter circuit 51 is disposed inside the chamber 10. However, in another embodiment, the series resonant circuit 511 may be provided outside the chamber 10, for example, on the side of the second filter circuit 52 via a pipe 53. Alternatively, the series resonant circuit 511 may be provided outside the chamber 10 via a pipe 53, for example, and further connected to the second filter circuit 52 via the pipe 53.

[0079] It should be noted that the disclosed embodiments are illustrative in all respects and should not be considered limiting. Indeed, the above-described embodiments may be embodied in various forms. Furthermore, the above-described embodiments may be omitted, substituted, or modified in various forms without departing from the scope and spirit of the appended claims. [Explanation of symbols]

[0080] S space W substrate 1. Plasma processing equipment 2. Device body 3. Control device 10 Chambers 12 Foundation 14 Support part 16 Cylindrical support 18 Exhaust duct 20 exhaust port 22 Exhaust pipe 24 Exhaust system 26 Gate valve 28 First RF power supply 29 Third RF Power Supply 30 Second RF power supply 32 Matching Units 34 Power supply rod 35 Cover 36 Edge Ring 38 Electrostatic Chuck 380 areas 40 Heater 42 Dielectric 44 electrode 45 DC power supply 46 Switch 500 filter circuit 50 Individual 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 paths 62 Piping 64 shower head 66 Electrode plate 68 Support 70 Diffusion Chamber 70a Gas inlet 72 Gas outlet 74 Processing gas supply unit 76 Piping 80 Distribution Department

Claims

1. 1. A filter circuit provided in a plasma processing apparatus that processes a substrate using plasma generated using power having a first frequency of 4 MHz or more and power having a second frequency of 100 Hz or more but less than 4 MHz, a first filter unit provided in a wiring between a conductive member provided in the plasma processing apparatus and a power supply unit that supplies control power, which is power of a third frequency less than 100 Hz or DC power, to the conductive member; a second filter unit provided on the wiring between the first filter unit and the power supply unit; Equipped with The first filter unit includes: a first coil connected in series to the wiring, the first coil having no core material or a first core material with a relative magnetic permeability of less than 10; a series resonant circuit that is connected between the wiring between the first coil and the second filter unit and ground, has a coil and a capacitor connected in series, and has a resonant frequency that is the first frequency or a frequency close to the first frequency; and The second filter unit includes: a second coil connected in series to the wiring between the first coil and the power supply unit, the second coil having a second core material with a relative magnetic permeability of 10 or more; A filter circuit having:

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

3. 3. The filter circuit according to claim 1, wherein the second core material is a dust material, a permalloy, or a cobalt-based amorphous material.

4. The second filter unit includes:

4. The filter circuit according to claim 1, further comprising a capacitor provided between a wiring between the second coil and the power supply unit and ground.

5. 5. The filter circuit according to claim 1, wherein the conductive member is a heater that controls the temperature of the substrate.

6. 6. The filter circuit according to claim 1, wherein the stray capacitance of a wiring between the conductive member and the first filter unit, a wiring between the first filter unit and the second filter unit, and a wiring between the second filter unit and the power supply unit is 500 pF or less.

7. a plurality of the conductive members are provided in the plasma processing apparatus, The first filter unit includes: a plurality of the first coils and one or more of the series resonant circuits; Each of the first coils is provided for each of the conductive members, The filter circuit according to claim 1 , wherein each of the series resonant circuits is provided in common for two or more of the first coils.

8. a plurality of the conductive members are provided in the plasma processing apparatus, the first filter unit has a plurality of the first coils, each of which is provided for one of the conductive members; the series resonant circuit includes a plurality of coils, each of which is provided for one of the conductive members, and one or more capacitors; each coil of the series resonant circuit is connected to a corresponding first coil; 6. The filter circuit according to claim 1, wherein each capacitor included in the series resonant circuit is provided in common for one or more of the first coils and one or more coils included in the series resonant circuit.

9. the power at the first frequency includes power at a plurality of different frequencies; The series resonant circuit is 8. A filter circuit according to claim 1, comprising a plurality of individual series resonant circuits each having a resonant frequency at a respective power frequency.

10. A plasma processing apparatus comprising the filter circuit according to claim 1 .

11. A plasma processing apparatus, a chamber for processing a substrate therein; a first RF power source that supplies power at a first frequency of 4 MHz or greater; a second RF power source that supplies power at a second frequency that is equal to or greater than 100 Hz and less than 4 MHz; a power supply unit that supplies a control power, which is a power having a third frequency of less than 100 Hz or a DC power, to a conductive member provided in the plasma processing apparatus; A filter circuit; Equipped with The filter circuit comprises: a first filter unit provided on a wiring between the conductive member and the power supply unit; a second filter unit provided on the wiring between the first filter unit and the power supply unit; and The first filter unit includes: a first coil connected in series to the wiring, the first coil having no core material or a first core material with a relative magnetic permeability of less than 10; a series resonant circuit that is connected between the wiring between the first coil and the second filter unit and ground, has a coil and a capacitor connected in series, and has a resonant frequency that is the first frequency or a frequency close to the first frequency; Including, The second filter unit includes: a second coil connected in series to the wiring between the first coil and the power supply unit, the second coil having a second core material with a relative magnetic permeability of 10 or more; A plasma processing apparatus comprising:

12. an electrostatic chuck on which a substrate is placed within the chamber; a base supporting the electrostatic chuck, the first RF power source and the second RF power source are electrically connected to the base; The plasma processing apparatus according to claim 11 .

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