Filtering circuit and plasma processing device

Abstract

The present application can eliminate the bias of plasma density distribution and improve the etching characteristics. A filter circuit for high-frequency power of a plasma processing apparatus having an electrode and a power supply connected to a central portion of a back surface of the electrode, which generates plasma by applying high-frequency power, wherein the filter circuit is provided on a wiring between a conductive member of the plasma processing apparatus and a power source that supplies direct-current power or power of a frequency of less than 400 kHz to the conductive member, and has a series resonance circuit having a coil connected in series to the wiring and a capacitor connected between the wiring and a ground, and a center axis of the coil coincides with a center axis of the power supply.

Description

Technical Field

[0001] This invention relates to filter circuits and plasma processing devices. Background Technology

[0002] For example, Patent Document 1 proposes a plasma processing device that superimposes a DC voltage via a filter when applying high-frequency (RF) power for plasma generation to the upper electrode.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2006-270017 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] If the frequency of the power applied to the electrodes is 100 MHz or higher, a bias may sometimes occur in the plasma density distribution due to the influence of the magnetic field generated by the coils in the filter.

[0008] The present invention provides a filter circuit and a plasma processing device that can eliminate the bias of plasma density distribution and improve etching characteristics.

[0009] Methods for solving problems

[0010] According to one aspect of the present invention, a high-frequency power filtering circuit for a plasma processing apparatus is provided, the plasma processing apparatus having electrodes and a power supply body connected to the center of the back side of the electrodes, plasma being generated by applying high-frequency power, wherein the filtering circuit is disposed on a wiring between a conductive component of the plasma processing apparatus and a power supply supplying DC power or power at a frequency of less than 400 kHz to the conductive component, and has a series resonant circuit having a coil connected in series with the wiring and a capacitor connected between the wiring and ground, the central axis of the coil being aligned with the central axis of the power supply body.

[0011] Invention Effects

[0012] In one respect, it can eliminate the bias in plasma density distribution and improve etching characteristics. Attached Figure Description

[0013] Figure 1 This is a diagram illustrating an example of a plasma processing system that includes the plasma processing apparatus of the embodiments.

[0014] Figure 2This is a diagram illustrating the structure of the filter circuit in the implementation method and an example of the singularity of the plasma density.

[0015] Figure 3 This is a diagram used to illustrate the control of the etching rate based on the coil configuration of the implementation method.

[0016] Figure 4 These are figures illustrating variations 1 and 2 of the filter circuit implementation method.

[0017] Figure 5 This is a diagram illustrating a modified example 3 of the shielding plate in the embodiment.

[0018] Figure 6 This is a diagram illustrating a variation 4 of the filter circuit implementation.

[0019] Figure 7 This is a diagram illustrating a method 1 for driving the coil of a filter circuit according to an embodiment.

[0020] Figure 8 This is a diagram illustrating method 2 for driving the coil of the filter circuit in an embodiment.

[0021] Explanation of reference numerals in the attached figures

[0022] 1. Plasma processing device

[0023] 2 Control Department

[0024] 10. Plasma processing chamber

[0025] 11. Substrate support portion

[0026] 13 nozzles

[0027] 13d electrode section

[0028] 13e and 111e conductive components

[0029] 14 Power supply unit

[0030] 21 Gas Source

[0031] 20 Gas Supply Department

[0032] 30 power supply

[0033] 31 RF Power Supply

[0034] 31a First RF Generation Unit

[0035] 31b Second RF Generation Section

[0036] 32a First DC Generation Unit

[0037] 32b Second DC Generation Unit

[0038] 50 Filtering Circuit

[0039] 51 coil

[0040] 52 Capacitor

[0041] 56 Shielding plate

[0042] 111 Main Body

[0043] 112 Ring Components Detailed Implementation

[0044] Hereinafter, embodiments for carrying out the present invention will be described with reference to the accompanying drawings. In the drawings, the same reference numerals are used to label the same components, and repeated descriptions are sometimes omitted.

[0045] The following describes a structural example of a plasma processing system.

[0046] [Plasma Processing System]

[0047] The plasma processing system includes a capacitively coupled plasma processing device 1 and a control unit 2. The capacitively coupled plasma processing device 1 includes a plasma processing chamber 10, a gas supply unit 20, a power supply 30, and an exhaust system 40. Additionally, the plasma processing device 1 includes a substrate support 11 and a gas inlet. The gas inlet is configured to introduce at least one processing gas into the plasma processing chamber 10. The gas inlet includes a nozzle 13. The substrate support 11 is disposed within the plasma processing chamber 10. The nozzle 13 is disposed above the substrate support 11. In one embodiment, the nozzle 13 constitutes at least a portion of the ceiling of the plasma processing chamber 10. The plasma processing chamber 10 has a plasma processing space 10s defined by the nozzle 13, the sidewall 10a of the plasma processing chamber 10, and the substrate support 11. Furthermore, the plasma processing chamber 10 has at least one gas supply port for supplying at least one processing gas to the plasma processing space 10s and at least one gas outlet for discharging gas from the plasma processing space. The sidewall 10a is grounded. The nozzle 13 is insulated from the plasma processing chamber 10 by an insulating component 16. The nozzle 13 and the substrate support 11 are electrically insulated from the housing of the plasma processing chamber 10.

[0048] The substrate support portion 11 includes a main body portion 111 and a ring assembly 112. The main body portion 111 has a central region (substrate support surface) 111a for supporting a substrate (wafer) W and an annular region (ring support surface) 111b for supporting the ring assembly 112. The annular region 111b of the main body portion 111 surrounds the central region 111a of the main body portion 111 when viewed from above. The substrate W is disposed on the central region 111a of the main body portion 111, and the ring assembly 112 is disposed on the annular region 111b of the main body portion 111 in such a way that it surrounds the substrate W on the central region 111a of the main body portion 111. In one embodiment, the main body portion 111 includes a base and an electrostatic chuck. The base includes a conductive member 111e. The conductive member 111e of the base functions as a lower electrode. The electrostatic chuck is disposed on the base. The upper surface of the electrostatic chuck has the substrate support surface 111a. The ring assembly 112 includes one or more annular members. At least one of the one or more annular components is an edge ring. Additionally, although not shown in the figure, the substrate support 11 may also include a temperature control module configured to adjust at least one of the electrostatic chuck, ring assembly 112, and substrate to a target temperature. The temperature control module may also include a heater, a heat-conducting medium, a flow path, or a combination thereof. A heat transfer fluid such as brine or gas flows in the flow path. Furthermore, the substrate support 11 may also include a heat transfer gas supply section configured to supply heat transfer gas between the back surface of the substrate W and the substrate support surface 111a.

[0049] The nozzle 13 is configured to introduce at least one processing gas from the gas supply unit 20 into the plasma processing space 10s. The nozzle 13 has at least one gas supply port 13a, at least one gas diffusion chamber 13b, and multiple gas inlets 13c. The processing gas supplied to the gas supply port 13a is introduced into the plasma processing space 10s through the gas diffusion chamber 13b and the multiple gas inlets 13c. Additionally, the nozzle 13 includes a conductive component 13e. The conductive component 13e of the nozzle 13 functions as an upper electrode. The gas inlet unit, in addition to the nozzle 13, may also include one or more side gas injectors (SGIs) installed in one or more openings formed in the sidewall 10a.

[0050] The gas supply unit 20 may also include at least one gas source 21 and at least one flow controller 22. In one embodiment, the gas supply unit 20 is configured to supply at least one processing gas from a corresponding gas source 21 to the nozzle 13 via a corresponding flow controller 22. Each flow controller 22 may, for example, include a mass flow controller or a pressure-controlled flow controller. Furthermore, the gas supply unit 20 may also include one or more flow modulation devices for modulating or pulsed flow of the at least one processing gas.

[0051] The power supply 30 includes an RF power supply 31 coupled to the plasma processing chamber 10 via at least one impedance matching circuit. The RF power supply 31 is configured to supply at least one RF signal (RF power), such as a source RF signal and a bias RF signal, to the conductive component 111e of the substrate support 11 and / or the conductive component 13e of the nozzle 13. As a result, plasma is formed from at least one processing gas supplied to the plasma processing space 10s. Therefore, the RF power supply 31 can function as at least part of a plasma generation unit configured to generate plasma from one or more processing gases in the plasma processing chamber 10. Furthermore, by supplying a bias RF signal to the conductive component 111e of the substrate support 11, a bias potential can be generated on the substrate W, introducing ionic components from the formed plasma into the substrate W.

[0052] In one embodiment, the RF power supply 31 includes a first RF generation unit 31a and a second RF generation unit 31b. The first RF generation unit 31a is configured to be coupled to the conductive component 111e of the substrate support 11 and / or the conductive component 13e of the nozzle 13 via at least one impedance matching circuit to generate a source RF signal (source RF power) for plasma generation. In one embodiment, the source RF signal has a frequency in the range of 13MHz to 150MHz. In one embodiment, the first RF generation unit 31a may also be configured to generate multiple source RF signals with different frequencies. The generated one or more source RF signals are supplied to the conductive component 111e of the substrate support 11 and / or the conductive component 13e of the nozzle 13. The second RF generation unit 31b is configured to be coupled to the conductive component 111e of the substrate support 11 via at least one impedance matching circuit to generate a bias RF signal (bias RF power). In one embodiment, the bias RF signal has a lower frequency than the source RF signal. In one embodiment, the bias RF signal has a frequency in the range of 400 kHz to 13.56 MHz. In another embodiment, the second RF generation unit 31b may also be configured to generate multiple bias RF signals with different frequencies. The generated one or more bias RF signals are supplied to the conductive member 111e of the substrate support 11. Furthermore, in various embodiments, at least one of the source RF signal and the bias RF signal may be pulsed.

[0053] Furthermore, in this embodiment, the source RF signal applies power at a frequency of 100 MHz to the conductive component 13e of the nozzle 13 within the plasma processing apparatus 1. Additionally, in this embodiment, the bias RF signal applies power at a frequency of 13 MHz to the conductive component 111e of the substrate support portion 11 within the plasma processing apparatus 1. However, this is not a limitation.

[0054] Alternatively, the power supply 30 may also include a DC power supply 32 connected to the plasma processing chamber 10. The DC power supply 32 includes a first DC generation unit 32a and a second DC generation unit 32b. In one embodiment, the first DC generation unit 32a is configured to connect to a conductive member 111e of the substrate support 11 to generate a first DC signal. The generated first bias DC signal is applied to the conductive member 111e of the substrate support 11. In one embodiment, the first DC signal may also be applied to other electrodes, such as electrodes within an electrostatic chuck. In one embodiment, the second DC generation unit 32b is configured to connect to a conductive member 13e of the nozzle 13 to generate a second DC signal. The generated second DC signal is applied to the conductive member 13e of the nozzle 13. In various embodiments, at least one of the first DC signal and the second DC signal may also be pulsed. Alternatively, a first DC generating unit 32a and a second DC generating unit 32b may be provided in addition to the RF power supply 31, or the first DC generating unit 32a may be provided instead of the second RF generating unit 31b. Furthermore, in order to apply a DC component voltage to the nozzle 13, power with a frequency of less than 400 kHz may be applied instead of the second DC generating unit 32b.

[0055] The exhaust system 40 can be connected, for example, to a gas outlet 10e located at the bottom of the plasma processing chamber 10. The exhaust system 40 may also include a pressure regulating valve and a vacuum pump. The pressure within the plasma processing space 10s is adjusted using the pressure regulating valve. The vacuum pump may also include a turbomolecular pump, a dry pump, or a combination thereof.

[0056] A filter circuit 50 is provided on the wiring 12 between the conductive component 13e and the power supply 30 that supplies DC power (second DC signal) to the conductive component 13e. Furthermore, the filter circuit 50 is connected to a power supply unit 14 located at the center of the back of the nozzle 13. As described later, the filter circuit 50 has a filtering function that captures high frequencies of the source RF signal from the first RF generation unit 31a.

[0057] The control unit 2 processes computer-executable commands that cause the plasma processing apparatus 1 to perform the various processes described herein. The control unit 2 can be configured to control the various elements of the plasma processing apparatus 1 in a manner that executes the various processes described herein. In one embodiment, part or all of the control unit 2 may be included in the plasma processing apparatus 1. The control unit 2 may, for example, include a computer 2a. The computer 2a may, for example, include a processing unit (CPU) 2a1, a storage unit 2a2, and a communication interface 2a3. The processing unit 2a1 can be configured to perform various control actions based on a program stored in the storage unit 2a2. The storage unit 2a2 may also include RAM (Random Access Memory), ROM (Read Only Memory), HDD (Hard Disk Drive), SSD (Solid State Drive), or combinations thereof. The communication interface 2a3 may also communicate with the plasma processing apparatus 1 via a communication line such as a LAN (Local Area Network).

[0058] [Filtering Circuit]

[0059] Next, refer to Figure 2 (a) and (b) describe the filter circuits 50 and 150. Figure 2 (c) indicates that the filter circuit 150 is set in the wiring 12. Figure 2 An example of a singularity in plasma density in a plasma processing space of 10s under the condition of position (a). Figure 2 (d) indicates that the filter circuit 50 is set in the wiring 12. Figure 2 Example of a singularity in plasma density in a plasma processing space of 10s under the condition of position (b).

[0060] like Figure 2 (a) and Figure 2 As shown in (b), high-frequency power as a source RF signal is applied to the nozzle 13 from the first RF generation unit 31a via a power supply unit 14 connected to the center of the back of the nozzle 13.

[0061] Figure 2 The filter circuit 150 shown in (a) is disposed in the wiring 12 between the conductive component 13e of the plasma processing apparatus 1 and the second DC generating unit 32b that supplies DC power to the conductive component 13e. Thus, the DC power from the second DC generating unit 32b is supplied to the power supply unit 14 via the filter circuit 150.

[0062] The filter circuit 150 is a series resonant circuit having a coil 151 connected in series with the wiring 12, and a capacitor 152 connected between the wiring 12 and ground on the side of the wiring 12 closer to the second DC generation section 32b than the coil 151. Through these structures of the filter circuit 150, high-frequency radio waves from the first RF generation section 31a, which serve as the source RF signal, are captured.

[0063] Similarly, Figure 2 The filter circuit 50 shown in (b) is disposed in the wiring 12 between the conductive component 13e of the plasma processing apparatus 1 and the second DC generating unit 32b that supplies DC power to the conductive component 13e. Thus, the DC power from the second DC generating unit 32b is supplied to the power supply unit 14 via the filter circuit 50.

[0064] The filter circuit 50 is a series resonant circuit having a coil 51 connected in series with the wiring 12, and a capacitor 52 connected between the wiring 12 and ground on the side of the second DC generation section 32b closer to the coil 51. Through these structures of the filter circuit 50, high-frequency radio waves from the first RF generation section 31a, which serve as the source RF signal, are captured. The filter circuit 50 can be located inside or outside the matching unit.

[0065] The first RF generation unit 31a sometimes applies power at a frequency of 100 MHz or higher to the nozzle 13 via the power supply unit 14. Thus, when a high frequency of 100 MHz or higher is applied to the power supply unit 14, in the case of... Figure 2 In structure (a), the wiring 12 from the power supply 14 to the filter circuit 150 is relatively long, resulting in a larger inductance (L component) and parasitic capacitance (C component) of the wiring 12. As a result, the plasma density distribution may be biased due to the influence of inductance and parasitic capacitance.

[0066] In addition, such as Figure 2 As shown in (c), a filter circuit 150 is disposed at a radially offset position from the power supply 14 disposed at the center of the top of the plasma processing chamber 10. Therefore, due to the influence of the coil 151 included in the filter circuit 150, a singularity C in the plasma density distribution is generated below the position where the filter circuit 150 is disposed, making it impossible to make the plasma density distribution uniform.

[0067] In contrast, in the filter circuit 50, the central axis of the coil 51 coincides with the central axis CL of the power supply body 14. "The central axis of the coil 51 coincides with the central axis CL of the power supply body 14" includes not only the case where the central axis of the coil 51 is exactly aligned with the central axis CL of the power supply body 14, but also the case where they are largely aligned. The coil 51 is located on the outer periphery of the power supply body 14 and is wound around the outer periphery of the power supply body 14. One end of the coil 51 is located on the nozzle 13 side and is connected to the power supply body 14 or the nozzle 13 itself, which is closer to the nozzle 13 side than the coil 51. The other end of the coil 51 is connected to the wiring 12. Furthermore, the filter circuit 50 is positioned near the power supply body 14 in a manner that minimizes the distance from the coil 51 to the capacitor 52.

[0068] Therefore, in Figure 2 In structure (b), the wiring 12 from the power supply unit 14 to the coil 51 can be removed, making the wiring 12 to the capacitor 52 more... Figure 2 (a) has a shorter structure. As a result, the effects of inductance and parasitic capacitance are reduced, making it difficult to produce a bias in the plasma density distribution.

[0069] In addition, Figure 2 In structure (b), a coil 51 is wound on a power supply unit 14 connected to the center of the plasma processing chamber 10. Therefore, as... Figure 2 As shown in (d), a singularity C in the plasma density distribution is generated below the location where the coil 51 is arranged in the filter circuit 50. Therefore, by setting the singularity C at the center of the plasma processing chamber 10, it is possible to avoid Figure 2 As shown in (c), the circumferential plasma bias can make the circumferential plasma density distribution uniform. Controlling the uniformity of the radial plasma density is easier than controlling the uniformity of the circumferential plasma density. For example, the correction method described below and other correction methods can be used to make the radial plasma density uniform. Thus, the plasma density distribution can be controlled.

[0070] Among them, Figure 2 and the following Figure 3 , Figure 4 The diagram shows the first RF generating unit 31a being connected to the conductive component 13e of the nozzle 13 via the power supply unit 14, but it is not limited to this. It is believed that the same effect would also be observed when the first RF generating unit 31a is connected to the conductive component 111e of the substrate support unit 11.

[0071] [Etching rate control based on coil configuration]

[0072] Next, refer to Figure 3 The control of the etching rate based on the configuration of coil 51 with filter circuit 50 and its effect are explained. Figure 3This is a diagram used to illustrate the control of the etching rate based on the configuration of coil 51 in the embodiment.

[0073] The central axis of coil 51 is aligned with the central axis CL of power supply unit 14, and coil 51 is wound around the power supply unit 14. Therefore, when a high-frequency power of, for example, 100 MHz is applied to power supply unit 14 from the first RF generation unit 31a, electromagnetic induction is generated by the high-frequency current flowing into coil 51, generating a magnetic field that penetrates coil 51. Due to the magnetic strength of the generated magnetic field, the magnetic field extends from the center to the outer periphery in the plasma processing space 10s. Therefore, electrons in plasma processing space 10s gyrate along the magnetic field. Through this gyratory motion of electrons, the plasma density becomes stronger in the outer peripheral region of plasma processing space 10s, which can increase the etching rate in the outer peripheral region of plasma processing space 10s and decrease the etching rate in the central region of plasma processing space 10s.

[0074] When a high-frequency power for plasma generation is applied to the upper electrode, the etching rate in the central region of the plasma processing space for 10 seconds tends to be higher than that in the outer region compared to when a high-frequency power for plasma generation is applied to the lower electrode. In particular, when a power with a frequency of 100 MHz or higher is applied to the upper electrode, the tendency for the etching rate to increase in the central region of the plasma processing space for 10 seconds becomes significant.

[0075] Therefore, in the filter circuit 50 of the embodiment, the coil 51 is wound around the outer periphery of the power supply body 14, and the generation of plasma is controlled by the electromagnetic induction generated by the high-frequency current flowing through the coil 51. That is, control is performed to increase the etching rate of the outer peripheral region of the plasma processing space 10s and decrease the etching rate of the central region of the plasma processing space 10s through the aforementioned electromagnetic induction. As a result, even when power with a frequency of 100MHz or higher is applied to the power supply body 14, the plasma density distribution can be homogenized not only in the circumferential direction but also in the radial direction, and the uniformity of the etching rate in the plasma processing space 10s can be controlled.

[0076] Furthermore, when the plasma density in the central region of the plasma processing space is higher than that in the outer region within 10 seconds, it is possible to use... Figure 7 and Figure 8The radial plasma density is made uniform by other correction methods, such as making the coil 51 movable, as described later. Controlling the radial plasma density uniformity is easier than controlling the circumferential plasma density uniformity. Therefore, the filter circuit 50 according to the embodiment can eliminate the bias in plasma density distribution and improve etching characteristics such as etching rate. Furthermore, as a method to make the radial plasma density uniform, correction methods such as pressure adjustment and magnet setting can be used, or combinations thereof. Additionally, to address the bias in plasma density distribution, as a gas introduction method, the etching rate can be made uniform by adjusting the amount of gas introduced into the central region compared to the amount introduced into the outer peripheral region of the plasma processing space for 10 seconds.

[0077] [Variation Example]

[0078] Next, refer to Figures 4-6 A variation of the filter circuit 50 of the embodiment will be described. Figures 4-6 These are figures illustrating variations 1 to 4 of the filter circuit 50 in the implementation method.

[0079] (Variation Example 1)

[0080] Figure 4 (a) is a diagram illustrating a modified example 1 of the filter circuit 50 according to the embodiment. In modified example 1, the coil 51 of the filter circuit 50 is disposed inside the power supply body 14, which is consistent with... Figure 2 (b) and Figure 3 The structure of the coil 51 wound around the power supply body 14 in the embodiment is different. Regarding other structures, the variation 1 is the same as the embodiment.

[0081] Specifically, in Modification 1, the interior of the power supply unit 14 becomes a cavity. The high-frequency current supplied from the first RF generation unit 31a flows through the surface of the power supply unit 14 and is supplied to the nozzle 13. Therefore, it is possible to make the interior of the power supply unit 14 a cavity. In Modification 1, the coil 51 is located within the cavity of the power supply unit 14. However, it is not limited to this; even if the interior of the power supply unit 14 is a cavity, the coil 51 can be wound around the outer periphery of the power supply unit 14.

[0082] (Variation Example 2)

[0083] Figure 4 (b) is a diagram illustrating a modified example 2 of the filter circuit 50 of the embodiment. In modified example 2, the shielding plate 56 is embedded in the nozzle 13, as shown in Figure 2. Figure 2 (b) and Figure 3 As shown, the structure differs from the embodiment without shielding plate 56. Regarding other structures, variation 2 is the same as the embodiment.

[0084] In Modification 2, a shielding plate 56 for shielding the magnetic field is embedded inside the nozzle 13 on the back side of the nozzle 13 connected to the power supply body 14. In Modification 2, the coil 51 of the filter circuit 50 is also wound around the outer periphery of the power supply body 14, and a magnetic field penetrating the coil 51 is generated by electromagnetic induction generated by the high-frequency current flowing through the coil 51.

[0085] The magnetic field, generated by the magnetic field, expands from the center outwards within the plasma processing space 10s. By embedding an electromagnetic shielding plate 56 within the nozzle 13, shielding is achieved so that the magnetic force does not reach the nozzle 13 and the plasma processing space 10s on the side opposite to the power supply 14, separated by the shielding plate 56. This reduces the plasma density in the central region of the plasma processing space 10s, allowing the plasma density to become uniform from the center outwards.

[0086] Preferably, the shielding plate 56 is embedded inside the nozzle 13. High-frequency current flows on the surface of the nozzle 13. Therefore, if the shielding plate 56 is disposed on the surface of the nozzle 13, the shielding plate 56 becomes a resistor, making it difficult for the high-frequency current to flow, thus reducing the energy efficiency that contributes to plasma generation. Conversely, if the shielding plate 56 is embedded inside the nozzle 13, a magnetic shielding effect that absorbs magnetic flux without impeding the flow of high-frequency current in the nozzle 13 through the shielding plate 56 can be obtained.

[0087] The shielding plate 56 is preferably made of a material with high magnetic permeability and low resistance to prevent heat generation. For example, the shielding plate 56 can be formed of soft magnetic metal materials such as permalloy, directional silicon steel, and iron-silicon-aluminum magnetic alloys, or soft magnetic electronic ceramic materials such as ferrite.

[0088] Furthermore, regarding the power supply body 14, materials such as aluminum with low permeability and low resistance are preferred. This allows the magnetic force generated by electromagnetic induction in the coil 51 to extend outwards from the power supply body 14 rather than being concentrated on its side.

[0089] (Variation Example 3)

[0090] In addition, such as Figure 5 As shown, relative to Figure 2 The structure shown in (a) also allows the shielding plate 56 to be embedded inside the nozzle 13. A magnetic field is generated toward the plasma processing space 10s using the magnetic field strength produced by the coil 151 included in the filter circuit 150. However, by embedding the shielding plate 56 within the nozzle 13 for electromagnetic shielding, shielding is achieved so that the magnetic force does not reach the nozzle 13 and the plasma processing space 10s on the side opposite to the power supply 14, separated by the shielding plate 56. Therefore, the singularity C of the plasma density distribution can be suppressed below the location where the filter circuit 150 is located, and the plasma density can be controlled to be uniform.

[0091] (Variation Example 4)

[0092] Figure 6 (a) is a diagram showing the coil 51 of the filter circuit 50 in the embodiment. In contrast, Figure 6 (b) and (c) are figures illustrating a modified example 4 of the filter circuit 50 of the embodiment. In modified example 4, with Figure 6 Compared to the embodiment shown in (a), the coil 51 differs in that it is configured to extend downward relative to the central axis CL of the power supply body 14. That is, in variation 4, the coil 51 is configured to extend towards the nozzle 13. Regarding other structures, variation 4 is the same as the embodiment.

[0093] In variation example 4, such as Figure 6 As shown in (b) and (c), the diameter of the coil 51 wound around the power supply body 14 increases towards the lower part, relative to the central axis CL of the power supply body 14, and the coil 51 expands in a trumpet shape. Figure 6 In (c), at the upper part of coil 51, the diameter of coil 51 is... Figure 6 (b) Same diameter, but in the lower part, the diameter of coil 51 is larger than... Figure 6 (b) Larger.

[0094] Therefore, as Figure 6 The curves below (a) to (c) are shown in the graph. Figure 6 When coil 51 of any shape from (a) to (c) is arranged in the power supply body 14, the magnetic field H is strongest at the central axis CL of the power supply body 14 and extends outwards. Figure 6 (b) In the shape of coil 51, with Figure 6 Compared to the shape of coil 51 in (a), the magnetic field H on the central axis CL of the power supply body 14 is weaker, while the magnetic field H extends more outwards. Additionally, in Figure 6 (c) In the shape of coil 51, with Figure 6 Compared to the shape of coil 51 in (b), the magnetic field H on the central axis CL of the power supply body 14 is weaker, and the magnetic field H extends further outward. That is, by making the shape of coil 51 into a horn shape with the lower part larger than the upper part on the nozzle 13 side, the magnetic field in the central region of the plasma processing space 10s can be weakened. As a result, the locally high etching rate in the central region of the plasma processing space 10s can be mitigated.

[0095] [Coil driving method]

[0096] The following is for reference Figure 7 and Figure 8 This describes a driving method for a coil 51 used to control the plasma density distribution and make the plasma density uniform by making the coil 51 movable. Figure 7 and Figure 8 The driving method of the coil shown can use any of the coils 51 of the filter circuit 50 in the embodiments and their variations. In this case, the coil 51 is movable along the central axis CL of the power supply body 14.

[0097] (Coil driving method 1)

[0098] Figure 7 This diagram illustrates a driving method 1 for coil 51. In driving method 1, coil 51 is connected to a vertical driving mechanism 58, which allows coil 51 to move vertically in the height direction.

[0099] The control unit 2 uses a vertical drive mechanism 58 to control the position (height) of the coil 51. For example, as Figure 7 As shown, the control unit 2 can also control the coil 51 to rise from its initial position H0 to position H1 (H1 > H0) using the up-down drive mechanism 58. This reduces the magnetic field reaching the plasma processing space 10s below the coil 51 and weakens the electric field in the plasma processing space 10s below the coil 51.

[0100] On the other hand, the control unit 2 can also control the coil 51 to descend from its initial position H0 to position H2 (H2 < H0) using the up-down drive mechanism 58. This enhances the magnetic field reaching the plasma processing space 10s below the coil 51 and strengthens the electric field within the plasma processing space 10s below the coil 51. Consequently, the plasma density distribution within the plasma processing space 10s below the coil 51 can be controlled, improving the controllability of the etching rate in the central region of the plasma processing space 10s.

[0101] (Coil driving method 2)

[0102] Figure 8 This diagram illustrates a driving method 2 for coil 51. In driving method 2, coil 51 is connected to a telescopic adjustment mechanism 59, which allows it to extend and retract along the central axis CL of the power supply unit 14.

[0103] The control unit 2 uses a telescopic adjustment mechanism 59 to control the length of the coil 51. For example, the coil 51 can also be fixed to the base position. Figure 8As shown, the control unit 2 can also use the telescopic adjustment mechanism 59 to control the length of the coil 51 to a length T1 (T1 > T0) that is longer than the initial length T0. In this way, by controlling the length of the coil 51 to extend or retract from its initial length T0, the strength of the magnetic field in the plasma processing space 10s under the coil 51 can be changed. This allows for changes in the distribution of the electric field in the plasma processing space 10s under the coil 51, control of the plasma density, and improved controllability of the etching rate in the central region of the plasma processing space 10s.

[0104] However, by extending or retracting the coil 51, the inductance of the filter circuit 50 changes. Therefore, when the coil 51 is extended or retracted, the capacitor 52 of the filter circuit 50 is operated according to the change in inductance, causing a change in conductance, thereby maintaining the function of the filter circuit 50.

[0105] exist Figure 3 The mechanism described is as follows: By winding coil 51 around the power supply body 14, plasma generation is controlled through electromagnetic induction generated by the high-frequency current flowing through coil 51, thus controlling the plasma density distribution in the central and outer regions of the plasma processing space 10s. Conversely, according to driving methods 1 and 2 for coil 51, the plasma density distribution can be further controlled by making coil 51 movable. Alternatively, coil 51 can be driven by combining the up-and-down driving mechanism 58 and the telescopic adjustment mechanism 59.

[0106] As explained above, the filter circuit 50 and the plasma processing apparatus 1 having the filter circuit 50 according to the embodiments and various modifications can eliminate the bias in plasma density distribution and improve etching characteristics.

[0107] In the above description, the coil 51 constituting the filter circuit 50 of the embodiment and various modifications is wound around the power supply body 14, and the capacitor 52 constituting the filter circuit 50 is provided on the wiring 12 that connects the second DC generation unit 32b to the power supply body 14. However, the arrangement of the coil 51 and the capacitor 52 of the filter circuit 50 is not limited to this.

[0108] The coil 51 of the filter circuit 50 can also be configured as a power supply wound around the back side of the conductive member 111e of the substrate support 11. Specifically, the coil 51 of the filter circuit 50 can be wound around a power supply connected to the center of the back side of the conductive member 111e of the substrate support 11, and high-frequency power as a source RF signal can be applied from the first RF generation unit 31a to the substrate support 11. In this case, the capacitor 52 of the filter circuit 50 can be connected between the power supply connected to the center of the back side of the conductive member 111e and the wiring connected to the first DC generation unit 32a and ground to form a series resonant circuit. Alternatively, the capacitor 52 of the filter circuit 50 can be connected between the power supply connected to the center of the back side of the conductive member 111e and the wiring connected to the second RF generation unit 31b and ground to form a series resonant circuit. Power with a frequency of less than 400 kHz is supplied from the second RF generation unit 31b.

[0109] The filter circuits and plasma processing apparatus of the embodiments disclosed herein are illustrative in all respects and should not be considered limiting. The embodiments can be modified and altered in various ways without departing from the appended claims and their spirit. The matters described in the foregoing embodiments can also be employed in other structures and combinations without contradiction.

[0110] The plasma processing apparatus of the present invention can be applied to any of the following types: Atomic Layer Deposition (ALD) apparatus, Capacitively Coupled Plasma (CCP), Inductively Coupled Plasma (ICP), Radial Line Slot Antenna (RLSA), Electron Cyclotron Resonance Plasma (ECR), and Helicon Wave Plasma (HWP).

[0111] In addition, any plasma processing device can be used to perform a prescribed plasma treatment on a substrate, and is not limited to etching devices. It can be applied to film forming devices, ashing devices, and other similar devices.

Claims

1. A filtering circuit for high-frequency power in a plasma processing apparatus having electrodes and a power supply connected to the center of the back side of the electrodes, wherein plasma is generated by applying high-frequency power, the filtering circuit being characterized in that: The filter circuit, A wiring arrangement is provided between a conductive component, which is connected to the power supply body and serves as an upper or lower electrode in the plasma processing device, and a power supply that supplies DC power or power at a frequency less than 400 kHz to the conductive component. It also has a series resonant circuit, which includes a coil connected in series with the wiring and a capacitor connected between the wiring and ground. The central axis of the coil is aligned with the central axis of the power supply.

2. The filter circuit as described in claim 1, characterized in that: One end of the coil is connected to a power supply or the electrode that is closer to the electrode than the coil.

3. The filter circuit as described in claim 1 or 2, characterized in that: The coil is located on the outer periphery of the power supply body.

4. The filter circuit as described in claim 1 or 2, characterized in that: The interior of the power supply body is hollow, and the coil is located inside the hollow.

5. The filter circuit as described in claim 1 or 2, characterized in that: High-frequency power at a frequency of 400 kHz or higher is applied to the electrodes via the power supply.

6. The filter circuit as described in claim 1 or 2, characterized in that: The coil is configured to extend axially toward the electrode side relative to the central axis of the power supply.

7. The filter circuit as described in claim 1 or 2, characterized in that: A shielding plate for shielding magnetic fields is embedded below the back of the electrode connected to the power supply and inside the electrode.

8. The filter circuit as described in claim 1 or 2, characterized in that: The coil is movable along the central axis of the power supply body.

9. The filter circuit as described in claim 1 or 2, characterized in that: The coil is connected to the up-down driving mechanism, which allows it to move up and down in the height direction of the coil.

10. The filter circuit as described in claim 1 or 2, characterized in that: The coil is connected to the telescopic adjustment mechanism, which allows it to extend or retract.

11. A plasma processing apparatus comprising: an electrode; a power supply connected to the center portion of the back side of the electrode; and a high-frequency power filtering circuit for generating plasma by applying high-frequency power, the plasma processing apparatus being characterized in that: The filter circuit, A wiring arrangement is provided between a conductive component, which is connected to the power supply body and serves as an upper or lower electrode in the plasma processing device, and a power supply that supplies DC power or power at a frequency less than 400 kHz to the conductive component. It also has a series resonant circuit, which includes a coil connected in series with the wiring and a capacitor connected between the wiring and ground. The central axis of the coil is aligned with the central axis of the power supply.

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