TW202201527A - Plasma processing device and substrate processing method including an impedance regulation device for regulating the impedance of a first radio frequency current path in order to distribute a radio frequency current to flow through the first radio frequency current path and a second radio frequency current path - Google Patents

Abstract

The present invention discloses a plasma processing device and a substrate processing method. The plasma processing device comprises: a reaction chamber, an upper electrode that is arranged on a top wall of the reaction chamber; a lower electrode that is located in the reaction chamber; a radio frequency power source that forms a radio frequency current between the lower electrode and the upper electrode; a plasma confinement ring that is arranged around the lower electrode; a neutral grounding ring that is arranged under the plasma confinement ring, a predetermined gap being present between one end of the neutral grounding ring that is close to a sidewall of the reaction chamber and the sidewall of the reaction chamber; and an impedance regulation device, which has one end of the impedance regulation device being connected with the sidewall of the reaction chamber, and another end being grounded. The impedance regulation device makes the impedance of a first radio frequency current path being regulated in order to realize a distribution of the radio frequency current flowing through the first radio frequency current path and a second radio frequency current path. The present invention can regulate uniformity of an etching rate and collimation.

Description

Plasma processing device and substrate processing method

The present invention relates to the technical field of semiconductor processing equipment, in particular to a plasma processing device and a substrate processing method.

During plasma etching, wafer-wide etch alignment is highly dependent on the following two factors: 1) The collimation of the electric field distribution of the sheath on the surface of the wafer; 2) The uniformity of plasma concentration distribution.

Factor 1 is also related to the plasma concentration distribution for the wafer-wide etch uniformity, especially the wafer center and middle positions. Usually, the plasma concentration shows a downward trend from the inside to the outside at the center of the wafer, resulting in the collimation of the sheath electric field on the entire wafer surface from the center point to the outside from vertical to gradually inclined, and the displayed plasma sputtering speed is Hat type, as shown in Figure 1.

The above effects will become more serious with the increase of the frequency of the plasma RF power source. The higher the frequency of the RF power source, the more obvious the intracavity harmonic effect. Studies have shown that for high-frequency plasma, the higher harmonics are generated by the nonlinear standing wave effect of the plasma.

Typically, the closer to the center of the wafer, the more obvious the standing wave effect, the more serious the superposition of high-order harmonics, and the higher the plasma concentration. The higher the frequency, the more high-order harmonics are generated in the cavity, and the more concentrated the plasma concentration distribution is at the center.

The above effect is more obvious in the high aspect ratio etching process, and the deeper the etching, the more obvious the non-collimation effect (Global tilting). And for a specific cavity, the RF current distribution is fixed and cannot be flexibly adjusted.

The purpose of the present invention is to provide a plasma processing device and a substrate processing method, so as to realize flexible regulation of the size of the two distribution paths of high-frequency or low-frequency radio frequency current in the cavity, so as to realize the uniformity of etching rate and collimation. The purpose of real-time adjustment.

In order to achieve the above object, the present invention realizes through the following technical solutions:

A plasma processing device, comprising: a reaction chamber; an upper electrode, arranged on the top wall of the reaction chamber; a lower electrode, located in the reaction chamber and arranged to be opposite to the upper electrode; a radio frequency power source, applied to the lower electrode and/or the upper electrode electrode to form a radio frequency current between the lower electrode and the upper electrode; a plasma confinement ring, arranged to surround the lower electrode; a neutral grounding ring, arranged under the plasma confinement ring, and one end of the neutral grounding ring close to the side wall of the reaction chamber and the reaction chamber There is a gap between the side walls of the chamber; an impedance adjusting device, one end of the impedance adjusting device is connected to the side wall of the reaction chamber, and the other end is grounded. The upper electrode is grounded through the side wall of the reaction chamber and the impedance adjusting device, forming a first RF current path for the RF current to pass through the upper electrode. The plasma confinement ring and the neutral ground ring form a second radio frequency current path for the radio frequency current to pass through the plasma confinement ring. The impedance of the first radio frequency current path is adjustable through the impedance adjusting device, so as to distribute the radio frequency current flowing through the first radio frequency current path and the second radio frequency current path.

Preferably, a lower grounding ring is disposed below the neutral grounding ring, and the lower grounding ring is electrically connected to the neutral grounding ring.

Preferably, the impedance adjusting device includes a grounding inductor, one end of the grounding inductor is connected to the neutral grounding ring, and the other end of the grounding inductor is connected to the side wall of the reaction chamber.

Preferably, the impedance adjustment device further comprises an adjustable capacitor, one end of the adjustable capacitor is connected to the lower grounding ring or the neutral grounding ring, and the other end of the adjustable capacitor is connected to the side wall of the reaction chamber.

Preferably, the adjustable capacitor is an electronically controlled motor capacitor.

Preferably, the number of ground inductors is at least two, and each ground inductor is connected in series.

Preferably, a fourth capacitor is formed between the neutral grounding ring and the side wall of the reaction chamber, by changing the shape or size of one end of the neutral grounding ring close to the side wall of the reaction chamber and adjusting the gap between the neutral grounding ring and the side wall of the reaction chamber. The size of the gap to realize the adjustment of the fourth capacitor.

Preferably, the frequency of the radio frequency power source is greater than or equal to 27MHz.

Preferably, a radio frequency bias power source is further included, and the radio frequency bias power source is used for applying a bias radio frequency signal with a frequency of less than or equal to 20 MHz to the lower electrode.

On the other hand, the present invention further provides a plasma processing device, which includes a reaction chamber, and the reaction chamber includes: a lower electrode for carrying a substrate to be processed; a plasma confinement ring, arranged around the periphery of the lower electrode; The ring is located under the plasma confinement ring, and a fourth capacitor is formed between the neutral grounding ring and the side wall of the reaction chamber; a grounding inductor is electrically connected to the side wall of the reaction chamber at one end, and the other end is grounded; and an adjustable capacitor, one end is connected to the reaction chamber The side wall is electrically connected, and the other end is grounded; wherein, the fourth capacitor, the ground inductance and the adjustable capacitor are connected in parallel.

Preferably, the adjustable capacitor is a motor capacitor.

In yet another aspect, the present invention further provides a method for processing a substrate, the method being performed in the plasma processing apparatus described above, the method comprising the steps of: moving the substrate into a reaction chamber. Process gas is delivered into the reaction chamber and dissociated into plasma. The impedance of the impedance adjusting device is adjusted so that the radio frequency current passing through the impedance adjusting device is changed.

Compared with the prior art, the present invention has at least the following advantages: the present invention is provided with an impedance adjusting device, through which the impedance of the first radio frequency current path can be adjusted to adjust the impedance of the first radio frequency current path and the second radio frequency current path. RF current is distributed. In this way, the distribution ratio of the high-frequency RF current in the middle and edge directions of the substrate is realized, and the distribution ratio of the low-frequency RF current in the middle and edge directions of the substrate remains unchanged, thereby realizing the etching rate and alignment. Uniformity is adjusted in real time.

A plasma processing apparatus and a substrate processing method proposed by the present invention will be further described in detail below with reference to FIGS. 1 to 6 and specific embodiments. The advantages and features of the present invention will become more apparent from the following description. It should be noted that the accompanying drawings are in a very simplified form and all use inaccurate scales, and are only used for the purpose of assisting in explaining the embodiments of the present invention conveniently and clearly. For the purpose, features and advantages of the present invention to be more clearly understood, please refer to the accompanying drawings. It should be noted that the structures, proportions, sizes, etc. shown in the drawings in this specification are only used to cooperate with the contents disclosed in the specification, so as to be understood and read by those who are familiar with the technology, and are not used to limit the implementation of the present invention. conditions, so it has no technical significance. Moreover, any modification of the structure or the change of the proportional relationship or the adjustment of the size should still fall within the scope covered by the technical content disclosed in the present invention under the premise of not affecting the effect that the present invention can produce and the purpose that can be achieved. Inside.

It should be noted that, in this document, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any relationship between these entities or operations. There is no actual relationship or order between them. Moreover, the terms "comprising", "comprising" or any other variation thereof are intended to encompass non-exclusive inclusion such that a process, method, article, or device comprising a list of elements not only includes the listed elements, but further includes not explicitly listed other elements, or further include elements inherent to such a process, method, article or apparatus. Without further limitation, an element qualified by the statement "comprises a..." does not preclude the further presence of additional identical elements in the process, method, article or apparatus that contains the element.

1 to 6 , the present embodiment provides a plasma processing device, including: a reaction chamber; an upper electrode 7 , which is arranged on the top wall 9 of the reaction chamber; The upper electrode 7 is opposite; the radio frequency power source is applied to the lower electrode 1 and/or the upper electrode 7 to form a radio frequency current between the lower electrode 1 and the upper electrode 7; the plasma confinement ring 5 is arranged around the lower electrode 1; the neutral grounding ring , is arranged under the plasma confinement ring 5, and there is a certain gap between one end of the neutral grounding ring close to the side wall 10 of the reaction chamber and the side wall 10 of the reaction chamber; the impedance adjustment device includes a parallel ground inductance 12 and an adjustable capacitor 13. The impedance One end of the adjusting device is connected to the side wall 10 of the reaction chamber, and the other end is grounded. The upper electrode 7 is grounded through the side wall 10 of the reaction chamber and the impedance adjusting device, forming a first RF current path Loop1 for the RF current to pass through the upper electrode 7 . The plasma confinement ring 5 and the neutral ground ring form a second radio frequency current path Loop2 that allows the radio frequency current to pass through the plasma confinement ring 5 . The impedance of the first radio frequency current path Loop1 is adjustable through the impedance adjusting device, so as to distribute the radio frequency current flowing through the first radio frequency current path Loop1 and the second radio frequency current path Loop2.

There is a gap between one end of the neutral grounding ring near the side wall 10 of the reaction chamber and the side wall 10 of the reaction chamber. It can be seen that the existence of the gap makes a fourth capacitor C4 formed between the neutral grounding ring and the side wall of the reaction chamber. The fourth capacitor C4, the grounding inductor 12 and the adjustable capacitor 13 are arranged in parallel. For high-frequency radio frequency current, the impedance generated by the grounding inductor 12 is relatively large, and it is difficult for the high-frequency radio frequency current to pass through. Therefore, most of the radio frequency current passes through the fourth capacitor C4 and the adjustable capacitor C4. The adjustable capacitor 13 enters the ground wire. At this time, by adjusting the size of the adjustable capacitor C0, the impedance on the first radio frequency current path Loop1 can be adjusted, and then the size of the radio frequency current flowing through the first radio frequency current path Loop1 can be adjusted, The radio frequency current flowing through the first radio frequency current path Loop1 and the second radio frequency current path Loop2 is distributed.

For the low frequency radio frequency current, since the capacitor has a blocking effect on the low frequency current, most of the low frequency radio frequency current enters the ground wire through the grounding inductor 12. Therefore, adjusting the adjustable capacitor 13 will not affect the low frequency current.

In this embodiment, the adjustable capacitor 13 is an electronically controlled motor capacitor, and the size of the adjustable capacitor 13 can be controlled from outside the reaction chamber. Therefore, the impedance on the first RF current path Loop1 can be adjusted online to meet the requirements of the same chip. The distribution of high-frequency RF current in the reaction chamber is adjusted during different wafer processes.

In this embodiment, the fourth capacitor C4 can be adjusted by changing the shape or size of one end of the neutral grounding ring close to the side wall 10 of the reaction chamber and adjusting the size of the gap between the neutral ground ring and the side wall 10 of the reaction chamber.

In this embodiment, a lower grounding ring 6 is disposed below the neutral grounding ring, and the lower grounding ring 6 is electrically connected to the neutral grounding ring. One end of the grounding inductor 12 is connected to the neutral grounding ring, and the other end is connected to the side wall 10 of the reaction chamber. One end of the adjustable capacitor 13 is connected to the lower grounding ring 6 or the neutral grounding ring, and the other end is connected to the side wall 10 of the reaction chamber.

In some embodiments, the number of ground inductors 12 is at least two, and each ground inductor 12 is connected in series. The number of adjustable capacitors 13 may be one or more (more than two), and multiple adjustable capacitors 13 may be connected in parallel.

The frequency of the RF power source is greater than or equal to 27MHz. In this embodiment, a radio frequency bias power source is further included, and the radio frequency bias power source is used for applying a bias radio frequency signal with a frequency of less than or equal to 20 MHz to the lower electrode 1 .

Please continue to refer to FIG. 1 to FIG. 3 , the first RF current path Loop1 (intermediate path) at least includes: the plasma between the upper electrode 7 and the lower electrode 1 , the upper ground ring 11 , the mounting substrate 8 , the inner wall of the cavity ( Including top wall 9 and side wall 10), impedance adjustment device and neutral grounding ring and/or lower grounding ring 6.

The second RF current path Loop2 (edge path) at least includes: plasma between the upper electrode 7 and the lower electrode 1 , a plasma confinement ring 5 , a neutral ground ring and a lower ground ring 6 .

Wherein, as shown in FIG. 3 and FIG. 6 , the first radio frequency current path Loop1 includes a first capacitor C1 , a first resistor R1 and an impedance adjusting device. The first capacitor C1 is connected in parallel with the first resistor R1, and is then connected to one end of the impedance adjusting device, and the other end of the impedance adjusting device is grounded. In this embodiment, the adjustable capacitor C0, the ground inductance L1 and the fourth capacitor C4 in the impedance adjustment device are connected in parallel with each other.

A first capacitor C1 is formed between the upper electrode 7 and the lower electrode 1, and a fourth capacitor C4 is formed between the side wall 10 of the reaction chamber and the neutral grounding ring. The first resistor R1 is the resistance generated by the plasma in the reaction chamber and the components that transmit RF current on the first RF current path Loop1 (the upper grounding ring 11 , the mounting substrate 8 , the inner wall of the chamber, the impedance adjustment device and the neutral grounding ring). and/or the sum of the resistances produced by the lower ground ring 6). The grounding inductor L1 is constituted by a conductive structure such as copper skin.

Specifically, the fourth capacitor C4 is coupled to the neutral grounding ring and the lower grounding ring 6 to form the first sub-radio frequency current path Loop1-1. The grounding inductor L1, the neutral grounding ring and the lower grounding ring 6 constitute the second sub-radio frequency current path Loop1-2. The adjustable capacitor C0 is coupled to the lower ground ring 6 to form a third sub-radio frequency current path Loop1-3.

The second radio frequency current path Loop2 includes a second capacitor C2, a second resistor R2 and a third capacitor C3. The second capacitor C2 is connected in parallel with the second resistor R2, and then one end of the second capacitor C2 and the second resistor R2 is connected to the radio frequency current, and the other end is connected to one end of the third capacitor C3, and the other end of the third capacitor C3 is connected to the radio frequency current. One end is grounded.

A second capacitor C2 is formed between the lower electrode and the plasma confinement ring 5 . A third capacitor C3 is formed between the plasma confinement ring 5 and the neutral grounding ring, and the capacitance value of the third capacitor C3 is determined by the area and gap of the contact surface between the plasma confinement ring 5 and the neutral grounding ring. The second resistance R2 is the sum of the resistance generated by the plasma in the reaction chamber and the resistance generated by the plasma confinement ring 5 .

Specifically, with reference to FIG. 3 to FIG. 6 , the impedance of the first RF current path Loop1 can be adjusted to distribute the RF current flowing through the first RF current path Loop1 and the second RF current path Loop2. the purpose of the process.

By adjusting the size of the adjustable capacitor C0 in the third sub-RF current path Loop1-3 to adjust the overall RF impedance of the first RF current path Loop1, the RF current is realized between the first RF current path Loop1 and the second RF current path Loop2. distribution and regulation. FIG. 6 provides the impedance adjustment of the first radio frequency current path Loop1 for different frequencies. Obviously, for a high-frequency radio frequency current, such as 60 MHz, controlling the size of the adjustable capacitor C0 can realize the impedance control of the first radio frequency current path Loop1. In addition, taking the capacitance value of the fourth capacitor C4 as 50pF as an example, when the adjustment range of the capacitance value of the adjustable capacitor C0 is 10pF~60pF, the corresponding impedance of the first RF current path Loop1 is 33.0Ohm~262.7Ohm, and Monotonic continuous change. For low-frequency RF currents, such as 2MHz and 400kHz, the impedance of the first RF current path Loop1 has no response to the adjustable capacitor C0, that is, most of the low-frequency RF currents pass through the second sub-RF current paths Loop1-2, because The capacitor blocks the low frequency, and the impedance adjustment device is equivalent to the low frequency radio frequency current distribution path, as shown in Figure 5 and Figure 4.

Through the above analysis, it can be seen that the distribution ratio of the high frequency radio frequency current in the middle and edge directions of the substrate 2 can be realized through the control of the adjustable capacitor C0, while the low frequency radio frequency current in the middle and edge directions of the substrate 2. The distribution ratio of the RF current remains unchanged, enabling real-time adjustment of the uniformity of the etching rate and collimation within the reaction chamber.

On the other hand, based on the same inventive idea, please continue to refer to FIG. 1 , the present invention further provides a plasma processing device, which includes a reaction chamber, and the reaction chamber includes: a lower electrode 1 for carrying a substrate 2 to be processed; plasma confinement The ring 5 is arranged around the periphery of the lower electrode 1; the middle ground ring is located under the plasma confinement ring 5, and a fourth capacitor C4 is formed between the middle ground ring and the side wall 10 of the reaction chamber; the ground inductance L1, one end is connected to the reaction chamber The side wall 10 of the reaction chamber is electrically connected, and the other end is grounded; and the adjustable capacitor 13, one end is electrically connected to the side wall 10 of the reaction chamber, and the other end is grounded. The fourth capacitor C4, the grounding inductor 12 and the adjustable capacitor 13 are connected in parallel. Preferably, the adjustable capacitor 13 is a motor capacitor. It can be seen from this that the distribution ratio of the high frequency radio frequency current in the middle and edge directions of the substrate 2 can be realized through the control of the adjustable capacitor 13 , while the low frequency radio frequency current in the middle and edge directions of the substrate 2 The radio frequency distribution ratio can be realized. The distribution ratio of the current remains unchanged, enabling real-time adjustment of the uniformity of the etch rate and collimation within the reaction chamber.

The plasma processing apparatus further includes an edge ring 4 and a process kit 3 . The edge ring 4 is arranged around the outer side of the lower electrode 1 (electrostatic chuck), and the process kit 3 is arranged on the edge ring 4 and around the substrate 2 . The process kit 3 is, for example, a focus ring and an isolation ring.

1 and 2 are schematic diagrams of the structure of a plasma processing apparatus according to an embodiment of the present invention, which are mainly used to show the positional relationship between the upper electrode 7, the lower electrode 1 and the side wall 10 and the transmission path of the high-frequency radio frequency current in the reaction chamber 1 and 2 do not show unrelated specific structures (eg, focus ring and spacer ring, etc.).

On the other hand, based on the same inventive idea, the present invention further provides a method for processing a substrate. The method is performed in the above-mentioned plasma processing apparatus, and the method includes the following steps: moving the substrate into a reaction chamber. Process gas is delivered into the reaction chamber and dissociated into plasma. The impedance of the impedance adjusting device is adjusted so that the radio frequency current passing through the impedance adjusting device is changed.

To sum up, the present invention is provided with an impedance adjustment device through which the impedance of the first RF current path can be adjusted to distribute the RF current flowing through the first RF current path and the second RF current path. In this way, the distribution ratio of high-frequency RF current in the middle and edge directions of the substrate is realized, and the distribution ratio of low-frequency RF current in the middle and edge directions of the substrate remains unchanged, so as to achieve uniform etching rate and alignment. real-time adjustment.

Although the content of the present invention has been described in detail with reference to the above preferred embodiments, it should be recognized that the above description should not be construed as limiting the present invention. Various modifications and alternatives to the present invention will be apparent to those of ordinary skill in the art upon reading the foregoing disclosure. Therefore, the protection scope of the present invention should be defined by the appended claims.

1: Lower electrode 2: Substrate 3: Process kit 4: Edge Ring 5: Plasma Confinement Ring 6: Lower ground ring 7: Upper electrode 8: Install the substrate 9: Top Wall 10: Sidewall 11: Upper ground ring 12: Ground Inductance 13: Adjustable Capacitor Loop1: The first RF current path Loop2: The second RF current path Loop1-1: The first sub-RF current path Loop1-2: Second sub-RF current path Loop1-3: The third sub-RF current path C0: Adjustable capacitor C1: first capacitor C2: second capacitor C3: the third capacitor C4: Fourth capacitor R1: first resistor R2: Second resistor L1: Ground Inductance

FIG. 1 is a schematic structural diagram of a plasma processing apparatus according to an embodiment of the present invention; 2 is a schematic diagram of a radio frequency current distribution in a plasma processing apparatus according to an embodiment of the present invention; 3 is an equivalent circuit diagram of a radio frequency current distribution of a plasma processing apparatus according to an embodiment of the present invention; 4 is a schematic diagram of a low frequency radio frequency current distribution of a plasma processing apparatus according to an embodiment of the present invention; FIG. 5 is an equivalent circuit diagram of a low-frequency radio frequency current distribution of a plasma processing apparatus according to an embodiment of the present invention; FIG. 6 shows the impedance adjustment of the first radio frequency current path of the plasma processing apparatus to different frequency sources according to an embodiment of the present invention.

1: Lower electrode

2: Substrate

3: Process kit

4: Edge Ring

5: Plasma Confinement Ring

6: Lower ground ring

7: Upper electrode

8: Install the substrate

9: Top Wall

10: Sidewall

11: Upper ground ring

12: Ground Inductance

13: Adjustable Capacitor

Loop1: The first RF current path

Loop2: The second RF current path

Claims (12)

A plasma processing device comprising: a reaction chamber; an upper electrode, arranged on the top wall of the reaction chamber; a lower electrode, located in the reaction chamber and arranged to be opposite to the upper electrode; a radio frequency power source applied to the lower electrode and/or the upper electrode to form a radio frequency current between the lower electrode and the upper electrode; a plasma confinement ring arranged to surround the lower electrode; a neutral grounding ring disposed under the plasma confinement ring, and a gap is formed between one end of the neutral grounding ring close to the side wall of the reaction chamber and the side wall of the reaction chamber; and An impedance adjustment device, one end of the impedance adjustment device is connected to the side wall of the reaction chamber, and the other end is grounded, the upper electrode is grounded through the side wall of the reaction chamber and the impedance adjustment device, forming a first RF current to pass through the upper electrode. a radio frequency current path; wherein the plasma confinement ring and the neutral ground ring form a second radio frequency current path for the radio frequency current to pass through the plasma confinement ring; The impedance of the first radio frequency current path is adjustable through the impedance adjustment device, so as to distribute the radio frequency current flowing through the first radio frequency current path and the second radio frequency current path. The plasma processing apparatus of claim 1, wherein a lower ground ring is disposed below the neutral ground ring, and the lower ground ring is electrically connected to the neutral ground ring. The plasma processing device of claim 1, wherein the impedance adjusting device comprises: a grounding inductor, one end of the grounding inductor is connected to the neutral grounding ring, and the other end of the grounding inductor is connected to the side wall of the reaction chamber. The plasma processing device of claim 2, wherein the impedance adjustment device further comprises: an adjustable capacitor, one end of the adjustable capacitor is connected to the lower ground ring or the neutral ground ring, and the other end of the adjustable capacitor is connected to the reaction The side walls of the cavity are connected. The plasma processing device of claim 4, wherein the adjustable capacitor is an electronically controlled motor capacitor. The plasma processing device of claim 3, wherein the number of the ground inductors is at least two, and the ground inductors are connected in series. The plasma processing apparatus of claim 1, wherein a fourth capacitor is formed between the neutral ground ring and the side wall of the reaction chamber, by changing the shape of an end of the neutral ground ring close to the side wall of the reaction chamber or size and adjusting the size of the gap between the neutral grounding ring and the side wall of the reaction chamber to realize the adjustment of the fourth capacitance. The plasma processing apparatus of claim 1, wherein the frequency of the radio frequency power source is greater than or equal to 27MHz. The plasma processing apparatus of claim 1, further comprising a radio frequency bias power source for applying a bias radio frequency signal with a frequency less than or equal to 20 MHz to the lower electrode. A plasma processing device includes a reaction chamber, the reaction chamber includes: a lower electrode for carrying a substrate to be processed; A plasma confinement ring is arranged around the periphery of the lower electrode; a neutral grounding ring located under the plasma confinement ring, a fourth capacitor is formed between the neutral grounding ring and the side wall of the reaction chamber; a grounding inductor, one end is electrically connected to the side wall of the reaction chamber, and the other end is grounded; an adjustable capacitor, one end is electrically connected to the side wall of the reaction chamber, and the other end is grounded; The fourth capacitor, the ground inductance and the adjustable capacitor are connected in parallel. The plasma processing device of claim 10, wherein the adjustable capacitor is a motor capacitor. A substrate processing method, the method is carried out in the plasma processing apparatus as described in any one of claim 1 to claim 9, wherein the method comprises the steps of: moving a substrate into the reaction chamber; delivering a process gas into the reaction chamber and dissociating the process gas into plasma; The impedance of the impedance adjusting device is adjusted so that the radio frequency current passing through the impedance adjusting device is changed.

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