Plasma treatment unit

Abstract

The present invention aims to provide a technology for controlling complex numbers of high-frequency electric power with different frequencies. The plasma processing apparatus of the present invention is characterized in that: a third filter, a first inductor, and a variable capacitor are connected in series between a second filter and a second electrode; a fourth filter and a second inductor are connected in series between a second filter and a second electrode; and the third filter and the first inductor are connected in parallel, and the transmission path between the first filter and the first electrode is connected to the transmission path between the second filter and the third filter.

Description

Technical Field

[0001] This invention relates to a plasma processing apparatus. Prior Technology

[0002] Improving the uniformity of the etching process within the sample surface in plasma etching apparatus has been a long-standing challenge. One method to improve the uniformity of the process is to divide the electrode into multiple parts and adjust the high-frequency power applied to each of the divided electrodes, thereby controlling the intensity and distribution of the electric field within the wafer surface. Another method involves varying the frequency of the high-frequency power applied to the electrodes or overlapping high-frequency power of different frequencies.

[0003] For example, Patent Document 1 discloses the following content as a plasma processing apparatus or plasma processing method that improves the yield rate: plasma processing apparatus and plasma processing method. "A plasma processing apparatus or method, which uses plasma formed in a processing chamber to process a wafer of a processing object placed on a sample stage disposed in the processing chamber inside a vacuum container, is characterized by:" The wafer is processed by adjusting the high-frequency power supplied to the first and second electrodes in the aforementioned process. The first electrode is disposed inside the aforementioned sample stage. The second electrode is positioned inside a dielectric annular member disposed on the outer periphery of the sample stage's mounting surface, and is connected via a circuit consisting of a capacitor and a coil arranged in series. [Previous Technical Documents] [Patent Literature]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2021-48411 Summary of the Invention

[0005] (The problem that the invention aims to solve)

[0006] In Patent Document 1, the impedance is reduced by causing resonance in a circuit with a capacitor and coil arranged in series. Therefore, there is still room for improvement in adjusting the high-frequency power at frequencies other than the resonant frequency. Therefore, the present invention aims to provide a technique for controlling complex numbers of high-frequency electric power with different frequencies. (Methods used to solve problems)

[0007] To solve the above-mentioned problems, one representative plasma processing apparatus of the present invention includes: The treatment chamber contains plasma-treated samples; A first high-frequency power supply supplies high-frequency power at a first frequency to the first electrode via a first impedance matching device and a first filter with a second frequency as the cutoff frequency; A second high-frequency power supply, which supplies the aforementioned second-frequency high-frequency power to the second electrode via a second impedance matching device and a second filter with the aforementioned first frequency as the cutoff frequency; and The sample stage, on which the aforementioned sample is placed, Its characteristics are: The third filter, the first inductor, and the variable capacitor are connected in series between the aforementioned second filter and the aforementioned second electrode. The fourth filter and the second inductor are connected in series between the aforementioned second filter and the aforementioned second electrode, and the aforementioned third filter and the aforementioned first inductor are connected in parallel. The transmission path between the aforementioned first filter and the aforementioned first electrode is connected to the transmission path between the aforementioned second filter and the aforementioned third filter. [The effects of the invention]

[0008] According to the present invention, multiple high-frequency electrical currents with different frequencies can be controlled. Other issues, components, and effects not mentioned above can be understood from the following description of the form in which the invention is implemented. Simple Explanation of the Diagram

[0009] [Figure 1] is a diagram showing the conventional configuration when an electric current is applied to the divided electrodes. [Figure 2] is a diagram showing the frequency characteristics of the gain of a resonant circuit in a pattern. [Figure 3] is a diagram that schematically represents one example of high-frequency power applied to the first and second electrodes. [Figure 4] is a diagram showing the configuration of the plasma processing apparatus in the first embodiment. [Figure 5] is a diagram showing the frequency characteristics of the gain of a resonant circuit in a pattern. [Figure 6] is a diagram showing the configuration of the plasma processing apparatus of Modified Example 1. [Figure 7] is a diagram showing the configuration of the plasma treatment apparatus of Modified Example 2. [Figure 8] is a diagram showing the configuration of the plasma treatment apparatus of Modified Example 3. [Figure 9] is a diagram showing the configuration of the plasma treatment apparatus of Modified Example 4. [Figure 10] is a diagram showing the configuration of the plasma processing apparatus of Modified Example 5. [Figure 11] is a diagram showing the frequency characteristics of the gain of a resonant circuit in a pattern. [Figure 12] is a diagram showing the configuration of the plasma treatment apparatus of Modified Example 6. Implementation

[0010] Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the invention is not intended to be limited by these embodiments. Furthermore, in the drawings, the same reference numerals are used to denote the same parts. When the constituent elements having the same or identical functions are plural, there are cases where different subscripts are used to describe the same symbols. Furthermore, when it is not necessary to distinguish the constituent elements of such plural numbers, there are cases where the subscripts are omitted in the description. In order to facilitate understanding of the invention, the actual positions, sizes, shapes, and extents of the constituent elements shown in the drawings may not be represented. Therefore, the present invention is not necessarily limited to the positions, sizes, shapes, and extents shown in the drawings.

[0011] (Previous technologies) First, the relevant prior art will be explained with reference to Figures 1 to 3. Figure 1 is a diagram showing the conventional configuration when power is applied to the divided electrodes. The high-frequency power output from the high-frequency power supply 103 is impedance matched by the impedance matching device 104, and branched within the capacitor section 105, which consists of a fixed capacitor C and a variable capacitor VC. Then, it is applied to the first electrode 101 and the second electrode 102 respectively through the inductor section 106, which consists of a fixed inductor L and a variable inductor VL.

[0012] The variable capacitor VC of capacitor section 105, the inductor L and the variable inductor VL of inductor section 106 are connected in series to function as resonant circuit 107. Figure 2 is a diagram showing the frequency characteristics of the gain of the resonant circuit 107 in a pattern. When the capacitance of the resonant circuit 107 is set to C0 and the inductance is set to L0, the resonant frequency f0 of the resonant circuit 107 is expressed as in equation (1). The impedance of the resonant circuit 107 is minimized at the resonant frequency f0. Therefore, if the gain of the resonant circuit 107 is set as the vertical axis and the frequency of the input power is taken as the horizontal axis, the gain becomes maximum near the resonant frequency f0. The resonant frequency f0 of the resonant circuit 107 can be adjusted by changing the capacitance of the variable capacitor VC or the inductance of the variable inductor VL. For example, when the capacitance of the variable capacitor VC is reduced or the inductance of the variable inductor VL is reduced, the resonant frequency f0 increases, and the frequency characteristic shifts (offsets) from the solid curve to the dashed curve. For example, when the capacitance of the variable capacitor VC is increased or the inductance of the variable inductor VL is increased, the resonant frequency f0 decreases, and the frequency response shifts from a solid line curve to a dotted line curve.

[0013] Figure 3 is a schematic diagram illustrating one example of high-frequency power applied to the first electrode 101 and the second electrode 102. Straight line 301 represents the high-frequency power applied to the first electrode 101, and curve 302 represents the high-frequency power applied to the second electrode 102. In Figure 3, the high-frequency power is represented as the high-frequency output Vpp (Voltage peak to peak) [V]. In a general configuration, as shown in Figure 3, when the high-frequency output Vpp [V] applied to the first electrode 101 is set to α, the constant of the resonant circuit 107 is adjusted so that the high-frequency output Vpp applied to the second electrode 102 can be adjusted within a range of 0.5 to 2.0 times. However, since the resonant circuit 107 only holds a single resonant frequency, only that specific frequency can be adjusted; for other frequencies, it is difficult to supply an appropriate high-frequency output Vpp to the second electrode 102. Furthermore, when a wide range of adjustment is desired, the variation amplitude of the variable capacitor VC must be increased accordingly. For example, if it is desired to adjust the frequency of a complex number, a mechanism for circuit change can be installed in the capacitor section 105 or the inductor section 106. However, since hardware switching is used, the switching takes time and is therefore not suitable for practical use.

[0014] (First Implementation Form) Next, the first embodiment will be described with reference to Figures 4 and 5.

[0015] (constitute) Figure 4 is a diagram showing the configuration of the plasma processing apparatus in the first embodiment. The plasma treatment unit 400 is equipped with: The treatment chamber contains plasma-treated samples; The first high-frequency power supply 403 supplies high-frequency power at a first frequency A (hereinafter referred to as "A [Hz]") to the first electrode 401 via a first impedance matching device 405 and a first filter 408 with a second frequency B (hereinafter also referred to as "B [Hz]") as the cutoff frequency; The second high-frequency power supply 404 supplies second high-frequency power of second frequency B to the second electrode 402 via a second impedance matching device 406 and a second filter 409 with a first frequency A as the cutoff frequency; and A sample loading platform for holding samples. In the plasma processing apparatus 400, the third filter 410, the first inductor L1, and the variable capacitor VC are connected in series between the second filter 409 and the second electrode 402. The fourth filter 411 and the second inductor L2 are connected in series between the second filter 409 and the second electrode 402, and the third filter 410 and the first inductor L1 are connected in parallel. The transmission path between the first filter 408 and the first electrode 401 is connected to the transmission path between the second filter 409 and the third filter 410. This will be explained in detail below.

[0016] The plasma processing apparatus 400 includes a vacuum chamber 413, in which a wafer (sample) is plasma-processed within a processing chamber of the vacuum chamber 413. A first electrode 401 and a second electrode 402 are disposed within the processing chamber. Furthermore, the plasma processing apparatus 400 further includes a component disposed on the outer periphery of a sample stage, with the first electrode 401 disposed within the sample stage and the second electrode 402 disposed within the component. For example, when the plasma processing apparatus is an ECR (Electron Cyclotron Resonance) etching apparatus, to control the in-plane bias potential, the first electrode 401 may be disposed within the sample stage on which the wafer (sample) is placed, and the second electrode 402 may be disposed within the component disposed on the outer periphery of the sample stage. The first electrode 401 is an electrode with a circular plate shape, and the second electrode 402 is an annular electrode surrounding the first electrode 401 (hereinafter also referred to as "outer ring"), which can uniformly form a bias potential in the planar direction.

[0017] The first impedance matching unit 405 performs impedance matching between the first high-frequency power supply 403 and the first filter 408. The second impedance matching unit 406 performs impedance matching between the second high-frequency power supply 404 and the second filter 409. Furthermore, the first filter 408 and the third filter 410 have a cutoff frequency of B [Hz], while the second filter 409 and the fourth filter 411 have a cutoff frequency of A [Hz]. Additionally, A [Hz] is set to be smaller than B [Hz].

[0018] Furthermore, for convenience, the circuit configuration including the first filter 408, the second filter 409, the third filter 410, the fourth filter 411, the first inductor L1, the second inductor L2, and the variable capacitor VC is also referred to as the overlapping branch section 407. Also, for convenience, the circuit portion including the first inductor L1, the second inductor L2, and the variable capacitor VC is also referred to as the resonant circuit 412.

[0019] If we describe the flow of electricity in the circuit, the output of the first impedance matching device 405 is input to the first filter 408, and the output of the second impedance matching device 406 is input to the second filter 409. The output of the first filter 408 is split, and one part of the split output is input to the first electrode 401. The other part of the split output is combined with the output of the second filter 409. The combined output is then split and input to the third filter 410 and the fourth filter 411.

[0020] Furthermore, the output of the third filter 410 is input to the first inductor L1, and the output of the fourth filter 411 is input to the second inductor L2. The outputs of the first inductor L1 and the second inductor L2 are combined and input to the variable capacitor VC. The output of the variable capacitor VC is input to the second electrode 402.

[0021] The first filter 408, the second filter 409, the third filter 410, and the fourth filter 411 are so-called bandstop filters, which cut off specific frequency components, while allowing lower or wider frequency components to pass through without attenuation. Furthermore, the first inductor L1 and the second inductor L2 are, for example, coils. In addition, the capacitor C disposed between the first filter 408 and the first electrode 401 blocks the DC component flowing to the first electrode 401.

[0022] (action) Next, the operation of the plasma processing apparatus 400 will be explained with reference to FIG5. FIG5 is a diagram showing the frequency characteristics of the gain of the resonant circuit 412 in a schematic manner. FIG5(a) shows the case where the resonant circuit 412 is configured as a conventional resonant circuit, and FIG5(b) shows the case where the resonant circuit 412 has the configuration of FIG4.

[0023] When the resonant circuit 412, such as the conventional resonant circuit 107 shown in Figure 1, is generally an LC series circuit, the frequency characteristic of the gain of the resonant circuit 412 is as shown in Figure 5(a), increasing at the resonant frequency C. On the other hand, the first inductor L1 corresponds to the first frequency A, and the second inductor L2 corresponds to the second frequency B. Specifically, assuming that the resonant circuit 412 is an LC series circuit of the first inductor L1 and the variable capacitor VC, the resonant frequency becomes A [Hz].

[0024] Furthermore, assuming the resonant circuit 412 is an LC series circuit of the second inductor L2 and the variable capacitor VC, the resonant frequency becomes B [Hz]. The high-frequency power output from the first high-frequency power supply 403 is branched after passing through the first filter 408 in the overlapping branch section 407 and applied to the first electrode 401 and the second electrode 402 respectively. That is, the voltage applied to the second electrode 402 is adjusted at the resonant frequency C.

[0025] If we describe the changes in the circuit's power in sequence, the high-frequency power P output from the first high-frequency power supply 403 is branched after passing through the first filter 408 within the overlapping branch section 407, and is applied to the first electrode 401 and the second electrode 402 respectively. Furthermore, in the following description, the high-frequency power flowing to the first electrode 401 is designated as P1, and the high-frequency power flowing to the second electrode 402 is designated as P2.

[0026] Here, assuming the resonant circuit is configured as in the past, the first high-frequency power supply 403 is set to output high-frequency power P at a frequency that corresponds to the resonant frequency of FIG5(a), and the power is applied to the second electrode 402.

[0027] In contrast, in this case, the high-frequency power P2 applied to the second electrode 402 passes through the third filter 410. A portion of the power P22 branches within the resonant circuit 412 and flows towards the fourth filter 411. Then, it is reflected by the fourth filter 411, interfering with the power P21 applied to the second electrode 402. At this time, receiving the phase change in the delay direction generated when passing through the second inductor L2 within the resonant circuit 412 and the phase change in the travel direction generated by reflection at the fourth filter 411, the gain of the high-frequency power applied to the second electrode 402 is as shown in Figure 5(b). It rises sharply at lower frequencies than A[Hz] (e.g., region AL) and decreases sharply at higher frequencies than A[Hz] (e.g., region AH). Furthermore, the resonant frequency C in Figure 5 can be adjusted by changing the variable capacitor VC, allowing for offset adjustments so that regions AL and AH shift towards lower or higher frequencies.

[0028] Furthermore, the above description also applies to the relationship between the second high-frequency power supply 404, the second filter 409, the third filter 410, and the resonant circuit 412. Specifically, as shown in Figure 5(b), the gain of the high-frequency power supply increases sharply at frequencies lower than B [Hz] (e.g., region BL) and decreases sharply at frequencies higher than B [Hz] (e.g., region BH). Furthermore, the number of adjustable frequencies is not limited to 2; the number of adjustable frequencies can be increased depending on the number of filters and coils within the resonant circuit 412.

[0029] In this way, the steep slope of the gain generated by the third filter 410 and the fourth filter 411 can be actively utilized. For example, by fine-tuning the resonant frequency of the resonant circuit 412 during discharge, the high-frequency output of the second electrode 402 side can be significantly controlled simultaneously for two or more complex frequencies relative to the high-frequency output on the first electrode 401 side.

[0030] (Functions and Effects) As described above, according to this invention, multiple high-frequency electrical currents of different frequencies can be controlled. For example, the electrical current applied to the first electrode 401 and the electrical current applied to the second electrode 402 can be controlled in detail according to the conditions, thereby controlling the distribution of plasma in the surface direction and improving the in-plane uniformity of the etching process.

[0031] (Variation Example 1) Next, Modification 1 will be described with reference to FIG6. Modification 1 is a plasma processing apparatus that uses capacitively coupled plasma (CCP), and the points at which electricity is applied to the first upper electrode 604 and the second upper electrode 605 differ from the first embodiment. FIG6 is a diagram showing the configuration of the plasma processing apparatus of Modification 1. In the following description, components that are the same as or equivalent to those in the first embodiment described above are simplified or omitted.

[0032] The plasma processing apparatus 600 includes an antenna 619 facing the sample stage 601, and a second electrode (second upper electrode 605) is disposed within the antenna 619. Specifically, the plasma processing apparatus 600 is a processing chamber formed within a vacuum chamber 606, and includes a sample stage 601, a lower electrode 602, a wafer 603, a first upper electrode 604, and a second upper electrode 605. The configuration for applying power to the first upper electrode 604 and the second upper electrode 605 is the same as that of the plasma processing apparatus 400 in the first embodiment. The first high-frequency power supply 609, the second high-frequency power supply 610, the first impedance matching device 611, the second impedance matching device 612, and the overlapping branch 613 of the plasma processing apparatus 600 correspond to the first high-frequency power supply 403, the second high-frequency power supply 404, the first impedance matching device 405, the second impedance matching device 406, and the overlapping branch 407 of the plasma processing apparatus 400 in the first embodiment, respectively.

[0033] Furthermore, the first filter 614, the second filter 615, the third filter 616, and the fourth filter 617 of the overlapping branch 613 are the first filter 408, the second filter 409, the third filter 410, and the fourth filter 411 of the overlapping branch 407, respectively.

[0034] Furthermore, the first inductor L1, the second inductor L2, and the variable capacitor VC of the resonant circuit 618 are respectively the first inductor L1, the second inductor L2, and the variable capacitor VC of the resonant circuit 412.

[0035] The high-frequency power supply 607 for ion introduction outputs high-frequency power to the lower electrode 602. The impedance matching device 608 performs impedance matching on the output of the high-frequency power for ion introduction.

[0036] (Functions and Effects) In the plasma processing apparatus 600, a high-frequency electric field generated between the lower electrode 602 and the upper electrodes (first upper electrode 604 and second upper electrode 605) is used to generate plasma for plasma processing of the wafer 603. Since the plasma can be generated using the second upper electrode 605 and the antenna 619 while the distribution of the generated plasma can be controlled using the first upper electrode 604, the desired plasma distribution can be achieved. Furthermore, since multiple high-frequency electric currents with different frequencies can be controlled, the controllability of the etched shape can be improved compared with conventional CCP-type plasma processing devices.

[0037] (Variation Example 2) Next, we will describe Modification 2 with reference to FIG7. Modification 2 differs from the first embodiment in that the first electrode 702 and the second electrode 703 are electrodes of the same size and that the first electrode 702 and the second electrode 703 are arranged within the sample stage 701. FIG7 is a diagram showing the configuration of the plasma treatment apparatus of Modification 2. In the following description, the description of components that are the same as or equivalent to those in the first embodiment described above is simplified or omitted.

[0038] The plasma processing apparatus 700 is a processing chamber formed within a vacuum chamber 714, comprising a sample stage 701, a first electrode 702, and a second electrode 703. Specifically, the plasma processing apparatus 700 has a configuration in which the first electrode 702 and the second electrode 703 are arranged within the sample stage 701. The configuration for applying electricity to the first electrode 702 and the second electrode 703 is the same as that of the plasma processing apparatus 400 in the first embodiment. The first high-frequency power supply 704, the second high-frequency power supply 705, the first impedance matching device 706, the second impedance matching device 707, and the overlapping branch 708 of the plasma processing apparatus 700 correspond respectively to the first high-frequency power supply 403, the second high-frequency power supply 404, the first impedance matching device 405, the second impedance matching device 406, and the overlapping branch 407 of the plasma processing apparatus 400.

[0039] Furthermore, the first filter 709, the second filter 710, the third filter 711, and the fourth filter 712 of the overlapping branch 708 are respectively the first filter 408, the second filter 409, the third filter 410, and the fourth filter 411 of the overlapping branch 407 of the plasma processing apparatus 400 in the first embodiment.

[0040] Furthermore, the first inductor L1, the second inductor L2, and the variable capacitor VC of the resonant circuit 713 are respectively the first inductor L1, the second inductor L2, and the variable capacitor VC of the resonant circuit 412 of the plasma processing apparatus 400 in the first embodiment.

[0041] (Functions and Effects) The first electrode 702 and the second electrode 703 are electrodes of the same size, for example, having a semi-circular shape or a shape formed by dividing a ring. The distribution of plasma can be controlled simultaneously with multiple high-frequency electrical currents of different frequencies. According to Modified Example 2, the uniformity of the in-plane distribution can be improved regardless of the shape of the electrode.

[0042] (Variation Example 3) Next, we will describe Modification 3 with reference to FIG8. Modification 3 differs from the first embodiment in that the high-frequency power supply can output high-frequency power at multiple frequencies. FIG8 is a diagram showing the configuration of the plasma processing apparatus 800 of Modification 3. In the following description, the description of components that are the same as or equivalent to those in the first embodiment described above is simplified or omitted.

[0043] The plasma treatment unit 800 is equipped with: The processing chamber for plasma-treated samples; A plurality of high-frequency power supplies 8031~803n supply high-frequency power to the first electrode 801 and the second electrode 802: and A sample stage for holding samples. When n is set to an integer greater than or equal to 2, the nth high-frequency power supply 803 n supplies high-frequency power to the first electrode 801 via the nth impedance matching device 804 n and the nth filter 805 n, and supplies high-frequency power to the second electrode 802 via the nth impedance matching device 804 n, the nth filter 805 n, the 2nth filter 806 2n, the nth inductor L n and the variable capacitor VC.

[0044] Furthermore, the 2nth filter 806 2n and the nth inductor Ln are configured in parallel for the (2n-1)th filter 806 2n-1 and the (n-1)th inductor Ln-1. Also, the nth filter 805 n and the 2nth filter 806 2n have the nth frequency fn set as the pass frequency. Additionally, the case involving n high-frequency power supplies 803, n impedance matching devices 804, n filters 805, n filters 806, and n inductors is described, but this invention is not limited to this case. This invention can also be applied to cases with more than n units.

[0045] In detail, the plasma processing apparatus 800 includes a vacuum chamber 809, in which a wafer (sample) is plasma-processed within a processing chamber. A first electrode 801 and a second electrode 802 are disposed within the processing chamber. Furthermore, the plasma processing apparatus 800 includes a component disposed on the outer periphery of a sample stage, with the first electrode 801 disposed within the sample stage and the second electrode 802 disposed within the component. The configuration for applying electricity to the first electrode 801 and the second electrode 802 is the same as that of the plasma processing apparatus 400 in the first embodiment.

[0046] The m-th (where m is any integer from 1 to n) high-frequency power supply 803m among the complex high-frequency power supplies 8031 ​​to 803n is a high-frequency power supply with an output frequency fm. Furthermore, the m-th impedance matching device 804m performs impedance matching between the m-th high-frequency power supply 803m and the m-th filter 805m.

[0047] The nth filter 805n and the 2nth filter 8062n are so-called bandpass filters, allowing specific frequency components to pass while cutting off lower or wider frequency components. The passing frequency of the first filter 8051 and the (n+1)th filter 806n+1 is f1, the passing frequency of the second filter 8052 and the (n+2)th filter 806n+2 is f2, and so on, up to the passing frequency of the nth filter 805n and the 2nth filter 8062n is fn. The downstream of the (n+1)th filter 806n+1 to the 2nth filter 8062M are connected to inductors L1, L2, and so on, with each inductor corresponding to the passing frequency of the connected filter. The outputs of the n inductors L1 to Ln are connected to the variable capacitor VC. In addition, regarding the frequency, for example, it can be set to be the maximum at f0, and decrease as it becomes f1, ..., fn.

[0048] For convenience, the circuit configuration including filters 8051~805n, filters 806n+1~8062n, resonant circuit 807, capacitor C, inductors L1~Ln, and variable capacitor VC is also referred to as the overlapping branch 808. The circuit configuration including inductors L1~Ln and variable capacitor VC is also referred to as the resonant circuit 807.

[0049] (Functions and Effects) The gain of the resonant circuit 807 increases sharply around n frequencies, including f1, f2, and even fn. By selecting the frequency of the high-frequency power output from the high-frequency power supply 803 from any of f1, f2, or even fn, the large gain can be utilized, and the power applied to the second electrode 802 can be easily controlled. Even assuming the frequency of the high-frequency power is limited, the resonant circuit 807 can be used to utilize the gain characteristics by adjusting the frequency of the high-frequency power output from the high-frequency power source.

[0050] (Variation Example 4) Next, we will describe Modification 4 with reference to FIG9. Modification 4 differs from Modification 2 in that the configuration of the resonant circuit 713 is changed. FIG9 is a diagram showing the configuration of the plasma processing apparatus 900 of Modification 4. In the following description, the description of components that are the same as or equivalent to the first embodiment described above is simplified or omitted.

[0051] The plasma treatment unit 900 is equipped with: The processing chamber for plasma-treated samples; A first high-frequency power supply 904 supplies high-frequency power at the first frequency A to the first electrode 902 via a first impedance matching device 906 and a first filter 909 with a cutoff frequency of the second frequency B. The second high-frequency power supply 905 supplies the second high-frequency power of the second frequency B to the second electrode 903 via the second impedance matching device 907 and the second filter 910 with the first frequency A as the cutoff frequency; and Sample stage 901 for placing sample. In the plasma processing apparatus 900, the third filter 911, the first capacitor C1, and the variable inductor VL are connected in series between the second filter 910 and the second electrode 903. The fourth filter 912 and the second capacitor C2 are connected in series between the second filter 910 and the second electrode 903, and the third filter 911 and the first capacitor C1 are connected in parallel. The transmission path between the first filter 909 and the first electrode 902 is connected to the transmission path between the second filter 910 and the third filter 911. This will be explained in detail below.

[0052] The plasma processing apparatus 900 is a processing chamber formed within a vacuum chamber 914, comprising a sample stage 901, a first electrode 902, and a second electrode 903. Specifically, the plasma processing apparatus 900 has a configuration in which the first electrode 902 and the second electrode 903 are arranged within the sample stage 901. The configuration for applying power to the first electrode 902 and the second electrode 903 is the same as that of the plasma processing apparatus 400 in the first embodiment. The first impedance matching device 906 performs impedance matching between the first high-frequency power supply 403 and the first filter 408. The second impedance matching device 406 performs impedance matching between the second high-frequency power supply 404 and the second filter 409. Furthermore, the first filter 408 and the third filter 410 have a cutoff frequency of B [Hz], and the second filter 409 and the fourth filter 411 have a cutoff frequency of A [Hz]. In addition, A [Hz] is set to be smaller than B [Hz].

[0053] Furthermore, the first filter 909, the second filter 910, the third filter 911, and the fourth filter 912 of the overlapping branch 908 are respectively the first filter 408, the second filter 409, the third filter 410, and the fourth filter 411 of the overlapping branch 407 of the plasma processing apparatus 400 in the first embodiment.

[0054] The resonant circuit 913 includes a first capacitor C1 and a second capacitor C2 with fixed capacitors, and a variable inductor VL. In the resonant circuit 913, it can be imagined that an LC series circuit of the first capacitor C1 and the variable inductor VL and an LC series circuit of the second capacitor C2 and the variable inductor VL are formed. By adjusting the values ​​of the first capacitor C1, the second capacitor C2, and the variable inductor VL, two resonant points can be set in the frequency response of the gain of the resonant circuit 913.

[0055] (Functions and Effects) In addition to using a combination of a fixed inductor and a variable capacitor to form a resonant circuit, a combination of a fixed capacitor and a variable inductor can also be used to form a resonant circuit, which can amplify the gain.

[0056] (Variation Example 5) Next, we will describe Modification 5 with reference to Figures 10 and 11. Modification 5 differs from the first embodiment in that the cutoff frequency of the first filter 1008 differs from the cutoff frequency of the third filter 1010, and the cutoff frequency of the second filter 1009 differs from the cutoff frequency of the fourth filter 1011. Figure 10 is a diagram showing the configuration of the plasma processing apparatus 1000 in Modification 5. Figure 11 is a diagram schematically showing the frequency characteristics of the gain of the resonant circuit 1012. In the following description, components that are the same as or equivalent to those in the first embodiment described above are simplified or omitted.

[0057] Plasma processing apparatus 1000, for example, a plasma etching apparatus. Plasma processing apparatus 1000 has a bias voltage application system, which includes: A first high-frequency power supply 1003 that outputs a high-frequency oscillation frequency A [Hz]. A second high-frequency power supply 1004 that performs high-frequency output of B[Hz]; The first impedance matching circuit 1005 performs impedance matching for the high-frequency output of A [Hz]. A second impedance matching circuit 1006 is used for impedance matching of the high-frequency output of B[Hz]; and The overlapping part 1007 is formed by superimposing the complex high-frequency outputs towards the electrode (first electrode) 1001 and the outer ring (second electrode) 1002. The overlapping branch 1007 includes: The first filter 1008 uses B1 [Hz] as its cutoff frequency; The second filter 1009 uses A1 [Hz] as its cutoff frequency; The third filter 1010 uses B2 [Hz] as its cutoff frequency; The fourth filter 1011 with A2 [Hz] as the cutoff frequency; and Resonant circuit 1012 with α [Hz] as the resonant frequency.

[0058] Furthermore, the relationship between the cut-off frequency values and the resonance frequency values of the respective circuits is A = A1 < A2 < α and B = B1 < B2 < α. In other words, the cut-off frequency A1 of the second filter 1009 is smaller than the cut-off frequency A2 of the fourth filter 1011, and the cut-off frequency A2 of the fourth filter 1011 is smaller than the resonance frequency α of the resonance circuit 1012 formed by the first inductor L1, the second inductor L2, and the variable capacitor VC. Also, the cut-off frequency B1 of the first filter 1008 is smaller than the cut-off frequency B2 of the third filter 1010, and the cut-off frequency B2 of the third filter 1010 is smaller than the resonance frequency α of the resonance circuit 1012.

[0059] In addition, the vacuum chamber 1013, the electrode 1001, and the outer peripheral ring 1002 respectively correspond to the vacuum chamber 413, the first electrode 401, and the second electrode 402 of the plasma processing apparatus 400 of the first embodiment. Also, the overlapping branch portion 1007 and the resonance circuit 1012 respectively correspond to the overlapping branch portion 407 and the resonance circuit 412 of the plasma processing apparatus 400 of the first embodiment.

[0060] (Operation) Next, the operation of the plasma processing apparatus 1000 will be described with reference to FIG. 11. FIG. 11 is a diagram schematically showing the frequency characteristics of the gain of the resonance circuit 1012.

[0061] In the plasma processing apparatus 1000, the high-frequency power P output from the first high-frequency power source 1003 passes through the first filter 1008, the third filter 1010, and the resonance circuit 1012, and is applied to the outer peripheral ring 1002. However, a part of the power branches at the resonance circuit 1012 and flows toward the fourth filter 1011 side. The power P2 flowing toward the fourth filter 1011 side is then reflected by the fourth filter 1011 and interferes with the power applied to the outer peripheral ring 1002. In addition, in FIG. 11, the power flowing toward the electrode 1001 is set as P1, and the power flowing toward the fourth filter 1011 side is set as P2. Also, among the power P2, the power flowing toward the fourth filter 1011 is set as P22, and the power flowing toward the outer peripheral ring 1002 is set as P21.

[0062] At this time, the phase-change power generated in the delay direction when passing through the second inductor L2 in the resonant circuit 1012 and the phase-change power generated in the travel direction by reflection from the fourth filter 1011 overlap with the original high-frequency power, forming a steep slope (e.g., region AL1), which is the frequency characteristic of the gain at frequency A [Hz]. By actively utilizing this slope, for example, by finely adjusting the resonant frequency α of the resonant circuit 1012 during discharge in the processing chamber of the vacuum chamber 1013, the high-frequency output on the outer ring 1002 side can be significantly controlled relative to the high-frequency output on the electrode 1001 side. In addition, in FIG11, the phase-change power in the delay direction through the second inductor L2 in power P22 is designated as P22d, and the phase-change power in the travel direction by reflection from the fourth filter 1011 is designated as P22a. Powers P22d and P22a overlap with power P21.

[0063] Furthermore, a sharp increase in gain occurs in region AL1, while a sharp decrease in gain occurs in region AL2, which contains frequency A2. Compared to region AL in the first embodiment, region AL1 is located on the high-frequency side. This is because the cutoff frequency A2 of the fourth filter 1011 is greater than the cutoff frequency A1 of the second filter 1009. Compared to the first embodiment, the sharp change in gain occurs at a higher frequency than frequency A [Hz], thus allowing for more flexible control of the high-frequency output on the outer peripheral loop 1002 side.

[0064] Furthermore, the above explanation also applies to the relationship between the second high-frequency power supply 1004, the second filter 1009, the third filter 1010, and the resonant circuit 1012. For example, as shown in region BL1 of FIG11, a steep slope of gain at frequency B [Hz] can be considered. Also, since region BH1 occurs at a higher frequency than region BH in the first embodiment, the high-frequency output on the outer peripheral ring 1002 side can be controlled more flexibly.

[0065] (Functions and Effects) By making the cutoff frequency of the third filter 1010 greater than that of the first filter 1008, and the cutoff frequency of the fourth filter 1011 greater than that of the second filter 1009, the region where the frequency response of the gain changes rapidly can be expanded. This allows for more flexible control of the high-frequency output.

[0066] (Variation Example 6) Next, referring to FIG. 12, Modification 6 will be described. Modification 6 shows a case where the frequency relationship of the filter of Modification 5 is applied to the configuration of Modification 4. FIG. 12 is a diagram showing the configuration of the plasma processing apparatus of Modification 6. In the following description, the description of the components that are the same as or equivalent to those of the above-described first embodiment or Modification 5 will be abbreviated or omitted.

[0067] The plasma processing apparatus 1100 is, for example, a plasma etching apparatus. The plasma processing apparatus 1100 has a bias application system, which includes: A first high-frequency power supply 1104 that outputs a high frequency of oscillation frequency A [Hz]; A second high-frequency power supply 1105 that outputs a high frequency of B [Hz]; A first impedance matcher 1106 that performs impedance matching for the high-frequency output of A [Hz]; A second impedance matcher 1107 that performs impedance matching for the high-frequency output of B [Hz]; and An overlapping and diverging section 1108 that diverges toward the first electrode 1102 and the second electrode 1103 after overlapping a plurality of high-frequency outputs. The overlapping and diverging section 1108 includes: A first filter 1109 having a cut-off frequency of B1 [Hz]; A second filter 1110 having a cut-off frequency of A1 [Hz]; A third filter 1111 having a cut-off frequency of B2 [Hz]; A fourth filter 1112 having a cut-off frequency of A2 [Hz]; and A resonance circuit 1113 having a resonance frequency of α1 [Hz].

[0068] Also, the relationship between the cut-off frequency values and the resonance frequency values of each circuit is A = A1 < A2 < α1, B = B1 < B2 < α1. In other words, the cut-off frequency A1 of the second filter 1110 is smaller than the cut-off frequency A2 of the fourth filter 1112, and the cut-off frequency A2 of the fourth filter 1112 is smaller than the resonance frequency α1 of the resonance circuit 1113 formed by the first capacitor C1, the second capacitor C2, and the variable inductor VL. Also, the cut-off frequency B1 of the first filter 1109 is smaller than the cut-off frequency B2 of the third filter 1111, and the cut-off frequency B2 of the third filter 1111 is smaller than the resonance frequency α1 of the resonance circuit 1113.

[0069] Furthermore, the sample stage 1101, vacuum chamber 1114, first electrode 1102, and second electrode 1103 correspond to the sample stage 901, vacuum chamber 914, first electrode 902, and second electrode 903 of the plasma processing apparatus 900 in Modified Example 4, respectively. Also, the overlapping branch 1108 and resonant circuit 1113 correspond to the overlapping branch 908 and resonant circuit 913 of the plasma processing apparatus 900 in Modified Example 4, respectively.

[0070] By adjusting the values ​​of the first capacitor C1, the second capacitor C2, and the variable inductor VL, two resonant points can be set in the frequency response of the gain of the resonant circuit 913. Furthermore, similar to Modification 5, by making the cutoff frequency of the third filter 1111 greater than the cutoff frequency of the first filter 1109, and the cutoff frequency of the fourth filter 1112 greater than the cutoff frequency of the second filter 1110, the region where the frequency response of the gain changes abruptly can be expanded.

[0071] (Functions and Effects) In addition to using a combination of a fixed inductor and a variable capacitor to form a resonant circuit, a combination of a fixed capacitor and a variable inductor can also be used to form a resonant circuit, which can amplify the gain.

[0072] The above describes the embodiments of the present invention, but the present invention is not limited to the embodiments described above, and various modifications can be made without departing from the spirit of the present invention.

[0073] The following description may constitute the content of this invention, but is not limited thereto. (Form 1) A plasma treatment apparatus comprising: The treatment chamber contains plasma-treated samples; A first high-frequency power supply supplies high-frequency power at a first frequency to the first electrode via a first impedance matching device and a first filter with a second frequency as the cutoff frequency; A second high-frequency power supply, which supplies the aforementioned second-frequency high-frequency power to the second electrode via a second impedance matching device and a second filter with the aforementioned first frequency as the cutoff frequency; and The sample stage, on which the aforementioned sample is placed, Its characteristics are: The third filter, the first inductor, and the variable capacitor are connected in series between the aforementioned second filter and the aforementioned second electrode. The fourth filter and the second inductor are connected in series between the aforementioned second filter and the aforementioned second electrode, and the aforementioned third filter and the aforementioned first inductor are connected in parallel. The transmission path between the aforementioned first filter and the aforementioned first electrode is connected to the transmission path between the aforementioned second filter and the aforementioned third filter. (Form 2) As described in aspect 1, the plasma processing apparatus wherein the aforementioned first frequency is lower than the aforementioned second frequency. (Form 3) The plasma processing apparatus as described in aspect 1 or 2 further includes a component disposed on the outer periphery of the aforementioned sample stage. The aforementioned first electrode is disposed within the aforementioned sample stage. The aforementioned second electrode is disposed within the aforementioned component. (Form 4) The plasma processing apparatus described in any of forms 1 to 3 further includes an antenna facing the aforementioned sample stage. The aforementioned second electrode is disposed within the aforementioned antenna. (Form 5) In any of the plasma processing apparatuses described in forms 1 to 4, the aforementioned first electrode and the aforementioned second electrode are disposed within the aforementioned sample stage. (Form 6) A plasma treatment apparatus comprising: The treatment chamber contains plasma-treated samples; A plurality of high-frequency power sources supply high-frequency power to the first electrode and the second electrode; and The sample stage, on which the aforementioned sample is placed, Its characteristics are: When n is set to an integer greater than or equal to 2, the nth high-frequency power supply supplies high-frequency power to the aforementioned first electrode via the nth impedance matching device and the nth filter, and supplies high-frequency power to the aforementioned second electrode via the aforementioned nth impedance matching device, the aforementioned nth filter, the 2nth filter, the nth inductor, and the variable capacitor. The aforementioned 2n-th filter and n-th inductor are configured in parallel with respect to the (2n-1)-th filter and the (n-1)-th inductor. The aforementioned nth filter and the aforementioned 2nth filter are filters that use the nth frequency as the pass frequency. (Form 7) A plasma treatment apparatus comprising: The treatment chamber contains plasma-treated samples; A first high-frequency power supply supplies high-frequency power at a first frequency to the first electrode via a first impedance matching device and a first filter with a second frequency as the cutoff frequency; A second high-frequency power supply, which supplies the aforementioned second-frequency high-frequency power to the second electrode via a second impedance matching device and a second filter with the aforementioned first frequency as the cutoff frequency; and The sample stage, on which the aforementioned sample is placed, Its characteristics are: The third filter, the first capacitor, and the variable inductor are connected in series between the aforementioned second filter and the aforementioned second electrode. The fourth filter and the second capacitor are connected in series between the aforementioned second filter and the aforementioned second electrode, and the aforementioned third filter and the aforementioned first capacitor are connected in parallel. The transmission path between the aforementioned first filter and the aforementioned first electrode is connected to the transmission path between the aforementioned second filter and the aforementioned third filter. (Form 8) In any of the plasma processing apparatuses described in forms 1 to 7, the cutoff frequency of the aforementioned second filter is smaller than the cutoff frequency of the aforementioned fourth filter. The cutoff frequency of the aforementioned fourth filter is smaller than the resonant frequency of the resonant circuit formed by the aforementioned first inductor, the aforementioned second inductor, and the aforementioned variable capacitor. The cutoff frequency of the first filter mentioned above is smaller than that of the third filter mentioned above. The cutoff frequency of the aforementioned third filter is smaller than the resonant frequency of the aforementioned resonant circuit. (Form 9) In any of the plasma processing apparatuses described in forms 1 to 7, the cutoff frequency of the aforementioned second filter is smaller than the cutoff frequency of the aforementioned fourth filter. The cutoff frequency of the aforementioned fourth filter is smaller than the resonant frequency of the resonant circuit formed by the aforementioned first capacitor, the aforementioned second capacitor, and the aforementioned variable inductor. The cutoff frequency of the first filter mentioned above is smaller than that of the third filter mentioned above. The cutoff frequency of the aforementioned third filter is smaller than the resonant frequency of the aforementioned resonant circuit.

[0074] 400: Plasma treatment device 401: First electrode 402: Second electrode 403: First High-Frequency Power Supply 404: Second High-Frequency Power Supply 405: First Impedance Matching Unit 406: Second Impedance Matching Unit 407: Overlapping bifurcation 408: First Filter 409: Second Filter 410: Third Filter 411: Fourth Filter 412: Resonant Circuit 413: Vacuum Chamber L1: First Inductor L2: Second inductor VC: Variable Capacitor 600: Plasma treatment device 601: Sample Testing Platform 602: Lower electrode 603: Wafer 604: First upper electrode 605: Second upper electrode 606: Vacuum Chamber 607: High-frequency power supply for ion introduction 608: Impedance Matching Device 609: First High-Frequency Power Supply 610: Second High-Frequency Power Supply 611: First Impedance Matching Unit 612: Second Impedance Matching Unit 613: Overlapping bifurcation 614: First Filter 615: Second Filter 616: Third Filter 617: Fourth Filter 618: Resonance Circuit 619: Antenna 700: Plasma treatment unit 701: Sample Testing Platform 702: First electrode 703: Second electrode 704: First High-Frequency Power Supply 705: Second High-Frequency Power Supply 706: First Impedance Matching Unit 707: Second Impedance Matching Unit 708: Overlapping bifurcation 709: First Filter 710: Second Filter 711: Third Filter 712: Fourth Filter 713: Resonant Circuit 714: Vacuum Chamber 800: Plasma treatment unit 801: First electrode 802: Second electrode 803 1~803 n: High-frequency power supply 804 1~804 n: Impedance matching circuit 805 1~805 n, 806 n+1~806 2n: Filters 807: Resonant Circuit 808: Overlapping bifurcation 809: Vacuum Chamber L1~Ln: Inductors 900: Plasma treatment unit 901: Sample Testing Platform 902: First electrode 903: Second electrode 904: First High-Frequency Power Supply 905: Second High-Frequency Power Supply 906: First Impedance Matching Unit 907: Second Impedance Matching Unit 908: Overlapping bifurcation 909: First Filter 910: Second Filter 911: Third Filter 912: Fourth Filter 913: Resonant Circuit 914: Vacuum Chamber C1: First capacitor C2: Second capacitor 1000: Plasma treatment device 1001: Electrode (First Electrode) 1002: Outer ring (second electrode) 1003: First High-Frequency Power Supply 1004: Second High-Frequency Power Supply 1005: First impedance matching circuit 1006: Second Impedance Matching Unit 1007: Overlapping bifurcation 1008: First Filter 1009: Second Filter 1010: Third Filter 1011: Fourth Filter 1012: Resonant Circuit 1013: Vacuum Chamber VL: Variable Inductor 1100: Plasma treatment device 1101: Sample Testing Platform 1102: First electrode 1103: Second electrode 1104: First High-Frequency Power Supply 1105: Second High-Frequency Power Supply 1106: First impedance matching circuit 1107: Second Impedance Matching Unit 1108: Overlapping bifurcation 1109: First Filter 1110: Second Filter 1111: Third Filter 1112: Fourth Filter 1113: Resonant Circuit 1114: Vacuum Chamber

Claims

1. A plasma treatment apparatus comprising: a treatment chamber for plasma treatment of a sample; a first high-frequency power supply that supplies high-frequency power at a first frequency to a first electrode via a first filter and a first impedance matching device, using a second frequency as a cutoff frequency; a second high-frequency power supply that supplies second high-frequency power at the second frequency to a second electrode via a second filter and a second impedance matching device, using the first frequency as a cutoff frequency; and a sample stage on which the sample is placed, characterized in that: a third filter, a first inductor, and a variable capacitor of the band-stop filter are connected in series between the second filter and the second electrode; a fourth filter and a second inductor of the band-stop filter are connected in series between the second filter and the second electrode; and the third filter and the first inductor are connected in parallel; the transmission path between the first filter and the first electrode is connected to the transmission path between the second filter and the third filter; and the cutoff frequency of the second filter is lower than the cutoff frequency of the fourth filter. The cutoff frequency of the aforementioned fourth filter is smaller than the resonant frequency of the resonant circuit formed by the aforementioned first inductor, the aforementioned second inductor, and the aforementioned variable capacitor. The cutoff frequency of the aforementioned first filter is smaller than the cutoff frequency of the aforementioned third filter. The cutoff frequency of the aforementioned third filter is smaller than the resonant frequency of the aforementioned resonant circuit.

2. A plasma treatment apparatus comprising: a treatment chamber for plasma treatment of a sample; a first high-frequency power supply that supplies high-frequency power of the first frequency to a first electrode via a first filter of a band-stop filter and a first impedance matching device at a second frequency as the cutoff frequency; a second high-frequency power supply that supplies second high-frequency power of the second frequency to a second electrode via a second filter of a band-stop filter and a second impedance matching device at the aforementioned first frequency as the cutoff frequency; and a sample stage on which the aforementioned sample is placed, characterized in that: a third filter of a band-stop filter, a first inductor, and a variable capacitor are connected in series between the aforementioned second filter and the aforementioned second electrode; a fourth filter of a band-stop filter and a second inductor are connected in series between the aforementioned second filter and the aforementioned second electrode; and the third filter and the aforementioned first inductor are connected in parallel; the transmission path between the aforementioned first filter and the aforementioned first electrode is connected to the transmission path between the aforementioned second filter and the aforementioned third filter; and the aforementioned first frequency is lower than the aforementioned second frequency.

3. A plasma treatment apparatus comprising: a treatment chamber for plasma treatment of a sample; a first high-frequency power supply that supplies high-frequency power of the first frequency to a first electrode via a first filter of a band-stop filter and a first impedance matching device at a second frequency as the cutoff frequency; a second high-frequency power supply that supplies second high-frequency power of the second frequency to a second electrode via a second filter of a band-stop filter and a second impedance matching device at the aforementioned first frequency as the cutoff frequency; and a sample stage on which the aforementioned sample is placed, characterized in that: a third filter of a band-stop filter, a first inductor, and a variable capacitor are connected in series between the aforementioned second filter and the aforementioned second electrode; a fourth filter of a band-stop filter and a second inductor are connected in series between the aforementioned second filter and the aforementioned second electrode; and the aforementioned third filter and the aforementioned first inductor are connected in parallel; a transmission path between the aforementioned first filter and the aforementioned first electrode is connected to a transmission path between the aforementioned second filter and the aforementioned third filter; and a member disposed on the outer periphery of the aforementioned sample stage; the aforementioned first electrode is disposed within the aforementioned sample stage; and the aforementioned second electrode is disposed within the aforementioned member.

4. A plasma processing apparatus comprising: a processing chamber for plasma processing of a sample; a first high-frequency power supply that supplies high-frequency power of the first frequency to a first electrode via a first filter of a band-stop filter and a first impedance matching device at a second frequency as the cutoff frequency; a second high-frequency power supply that supplies second high-frequency power of the second frequency to a second electrode via a second filter of a band-stop filter and a second impedance matching device at the aforementioned first frequency as the cutoff frequency; and a sample stage on which the sample is placed, characterized in that: a third filter of a band-stop filter, a first inductor, and a variable capacitor are connected in series between the aforementioned second filter and the aforementioned second electrode; a fourth filter of a band-stop filter and a second inductor are connected in series between the aforementioned second filter and the aforementioned second electrode; and the aforementioned third filter and the aforementioned first inductor are connected in parallel; a transmission path between the aforementioned first filter and the aforementioned first electrode is connected to a transmission path between the aforementioned second filter and the aforementioned third filter; and further comprising an antenna facing the sample stage, wherein the aforementioned second electrode is disposed within the aforementioned antenna.

5. A plasma treatment apparatus comprising: a treatment chamber for plasma treatment of a sample; a first high-frequency power supply that supplies high-frequency power of the first frequency to a first electrode via a first filter of a band-stop filter and a first impedance matching device at a second frequency as a cutoff frequency; a second high-frequency power supply that supplies second high-frequency power of the second frequency to a second electrode via a second filter of a band-stop filter and a second impedance matching device at the aforementioned first frequency as a cutoff frequency; and a sample stage on which the aforementioned sample is placed, characterized in that: a third filter of a band-stop filter, a first inductor, and a variable capacitor are connected in series between the aforementioned second filter and the aforementioned second electrode; a fourth filter of a band-stop filter and a second inductor are connected in series between the aforementioned second filter and the aforementioned second electrode; and the third filter and the aforementioned first inductor are connected in parallel; a transmission path between the aforementioned first filter and the aforementioned first electrode is connected to a transmission path between the aforementioned second filter and the aforementioned third filter; and the aforementioned first electrode and the aforementioned second electrode are disposed within the aforementioned sample stage.

6. A plasma treatment apparatus comprising: a treatment chamber for plasma treatment of a sample; a plurality of high-frequency power supplies for supplying high-frequency power to a first electrode and a second electrode; and a sample stage for holding the sample, characterized in that: when n is set to an integer of 2 or more, the nth high-frequency power supply supplies high-frequency power to the first electrode via an nth impedance matching device and an nth filter, and supplies high-frequency power to the second electrode via the nth impedance matching device, the nth filter, the 2nth filter, the nth inductor, and a variable capacitor; the 2nth filter and the nth inductor are configured in parallel with the (2n-1)th filter and the (n-1)th inductor; and the nth filter and the 2nth filter are filters with the nth frequency as the pass frequency.

7. A plasma treatment apparatus comprising: a treatment chamber for plasma treatment of a sample; a first high-frequency power supply that supplies high-frequency power at a first frequency to a first electrode via a first filter and a first impedance matching device using a second frequency as a cutoff frequency; a second high-frequency power supply that supplies second high-frequency power at the second frequency to a second electrode via a second filter and a second impedance matching device using the first frequency as a cutoff frequency; and a sample stage on which the sample is placed, characterized in that: a third filter, a first capacitor, and a variable inductor of the band-stop filter are connected in series between the second filter and the second electrode; a fourth filter and a second capacitor of the band-stop filter are connected in series between the second filter and the second electrode; the third filter and the first capacitor are connected in parallel; the transmission path between the first filter and the first electrode is connected to the transmission path between the second filter and the third filter; and the cutoff frequency of the second filter is lower than the cutoff frequency of the fourth filter. The cutoff frequency of the aforementioned fourth filter is smaller than the resonant frequency of the resonant circuit formed by the aforementioned first capacitor, the aforementioned second capacitor, and the aforementioned variable inductor. The cutoff frequency of the aforementioned first filter is smaller than the cutoff frequency of the aforementioned third filter. The cutoff frequency of the aforementioned third filter is smaller than the resonant frequency of the aforementioned resonant circuit.

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