Electrical Variable Capacitor(eVC) for RF Matching Networks

Abstract

An electrically variable capacitor applicable to an RF matching network according to an embodiment of the present disclosure comprises: a DC power supply; and a first variable capacitor section and a second variable capacitor section electrically connected to the DC power supply and connected to each other in a series manner; wherein the first variable capacitor section comprises a first switch and a second switch connected to each other in a series manner; a first variable capacitor and a first diode connected in parallel with the first and second switches and connected to each other in a series manner; a first inductor electrically connecting the middle of the first and second switches and the middle of the first variable capacitor and the first diode; and a third inductor connected in parallel with the first variable capacitor and the first diode; and wherein the second variable capacitor section comprises a third switch and a fourth switch connected to each other in a series manner; a second variable capacitor and a second diode connected in parallel with the third and fourth switches and connected to each other in a series manner. and a second inductor electrically connecting the middle of the third and fourth switches and the middle of the second variable capacitor and the second diode; and a fourth inductor connected in parallel with the second variable capacitor and the second diode; may be included.

Description

Technology Field

[0001] The disclosed content relates to an electrically variable capacitor, and more specifically, to an electrically variable capacitor for an RF matching network using a PN junction diode or a SiC (Schottky) diode. Background Technology

[0002] Unless otherwise indicated in this specification, the contents described in this section are not prior art for the claims of this application, and are not to be recognized as prior art simply because they are included in this section.

[0003] A plasma chamber is semiconductor equipment used for deposition or etching by accelerating and irradiating plasma particles onto a semiconductor substrate. Generally, reaction gases within the plasma chamber become plasma particles, and a high-frequency RF power source is required as an energy source to accelerate the generated plasma particles. An RF generator is a device that supplies high-frequency RF power into the plasma chamber. The impedance of the plasma chamber changes depending on the conditions inside the chamber; if there is a difference in impedance between the RF generator and the plasma chamber, some of the energy from the high-frequency RF power may be reflected, preventing the supply of the desired energy into the plasma chamber, which can cause defects in the semiconductor process.

[0004] To compensate for these impedance differences, an RF matching network is installed between the RF generator and the plasma chamber as an impedance matching circuit. RF matching networks come in two types: variable inductor and variable capacitor. While the variable inductor method adjusts inductance, it has the disadvantage of being difficult to control. Due to this drawback, the variable capacitor method is primarily used in impedance matching circuits. The variable capacitor method includes vacuum variable capacitors (VVC) and electric variable capacitors (eVC). The vacuum variable capacitor method changes capacitance by mechanically adjusting the distance between electrodes. However, because it uses a motor for adjustment, it suffers from the disadvantage of slow capacitance variation times. Slow capacitance variation times prolong semiconductor manufacturing process times, which can lead to a decrease in semiconductor yield. Consequently, there is growing interest in the electric variable capacitor method, which offers faster capacitance variation times. The problem to be solved

[0005] The disclosed content aims to provide an electrically variable capacitor using a PN junction diode or a SiC (Schottky) diode applicable to an RF matching network. means of solving the problem

[0006] An electrically variable capacitor applicable to an RF matching network according to an embodiment of the present disclosure comprises: a DC power supply; and a first variable capacitor section and a second variable capacitor section electrically connected to the DC power supply and connected to each other in a series manner; wherein the first variable capacitor section comprises a first switch and a second switch connected to each other in a series manner; a first variable capacitor and a first diode connected in parallel with the first and second switches and connected to each other in a series manner; a first inductor electrically connecting the middle of the first and second switches and the middle of the first variable capacitor and the first diode; and a third inductor connected in parallel with the first variable capacitor and the first diode; and wherein the second variable capacitor section comprises a third switch and a fourth switch connected to each other in a series manner; a second variable capacitor and a second diode connected in parallel with the third and fourth switches and connected to each other in a series manner. and a second inductor electrically connecting the middle of the third and fourth switches and the middle of the second variable capacitor and the second diode; and a fourth inductor connected in parallel with the second variable capacitor and the second diode; may be included.

[0007] As one embodiment, the electrically variable capacitor of the present disclosure may further include a unique capacitor connected in parallel to the first and second variable capacitor sections.

[0008] In one embodiment, the voltage of the DC power supply may be characterized as being a voltage of a constant magnitude.

[0009] In one embodiment, the first and second diodes may be PN junction diodes or SiC (Schottky) diodes.

[0010] In one embodiment, the first and second diodes may be connected in series in opposite directions to each other. Effects of the invention

[0011] The electrically variable capacitor applicable to the RF matching network of the present disclosure has the advantage of reducing the impedance matching time of the RF matching network due to rapid variation of capacitance as well as cost by using a PN junction diode or a SiC (Schottky) diode instead of an expensive PIN diode.

[0012] The effects of the present disclosure are not limited to the effects described above, and should be understood to include all effects that can be inferred from the detailed description of the present disclosure or the configuration of the invention described in the claims. Brief explanation of the drawing

[0013] Figure 1 is a configuration diagram of an RF matching network. Figure 2 is a circuit diagram of an electrically variable capacitor using a conventional PIN diode. FIG. 3 is a circuit diagram of an electrically variable capacitor according to an embodiment of the present disclosure. FIG. 4 is a conceptual diagram of the operating principle of an electrically variable capacitor according to an embodiment of the present disclosure. FIG. 5 is a circuit diagram of an electrically variable capacitor according to one embodiment of the present disclosure. FIG. 6 is a conceptual diagram of the operating principle of an electrically variable capacitor according to one embodiment of the present disclosure. FIG. 7 is a circuit diagram of an electrically variable capacitor according to another embodiment of the present disclosure. FIG. 8 is a conceptual diagram of the operating principle of an electrically variable capacitor according to another embodiment of the present disclosure. FIG. 9 is a circuit diagram of an electrically variable capacitor according to another embodiment of the present disclosure. FIG. 10 is a conceptual diagram of the operating principle of an electrically variable capacitor according to another embodiment of the present disclosure. Specific details for implementing the invention

[0014] Hereinafter, embodiments disclosed in this specification will be described in detail with reference to the attached drawings. Identical or similar components regardless of drawing symbols will be assigned the same reference number, and redundant descriptions thereof will be omitted. The suffixes "module" and "part" used for components in the following description are assigned or used interchangeably solely for the ease of drafting the specification and do not have distinct meanings or roles in themselves. Furthermore, in describing the embodiments disclosed in this specification, if it is determined that a detailed description of related prior art could obscure the essence of the embodiments disclosed in this specification, such detailed description will be omitted. Additionally, the attached drawings are intended only to facilitate understanding of the embodiments disclosed in this specification; the technical concept disclosed in this specification is not limited by the attached drawings, and it should be understood that they include all modifications, equivalents, and substitutions that fall within the concept and technical scope of this disclosure.

[0015] Terms including ordinal numbers, such as first, second, etc., may be used to describe various components, but said components are not limited by said terms. These terms are used solely for the purpose of distinguishing one component from another.

[0016] In this application, terms such as “comprising” or “having” are intended to specify the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0018] Hereinafter, an electrically variable capacitor according to an embodiment of the present disclosure will be described in detail with reference to the attached drawings.

[0019] FIG. 1 is a configuration diagram of the use of an RF matching network (30). An RF generator (10) is a device that supplies high-frequency RF power to a plasma chamber (20). The plasma chamber (20) uses the supplied high-frequency RF power to plasmaize a reaction gas and form plasma ions. An electric field is formed inside the plasma chamber (20), and the plasma ions are incident on the substrate by the electric field and react with the substrate. Through this, an etching or deposition process of the substrate is performed.

[0020] The impedance of the plasma chamber (20) changes depending on the environment of the plasma chamber (20) within the plasma chamber (20). Due to this, a portion of the high-frequency RF power supplied from the RF generator (10) may be reflected due to the difference in impedance between the plasma chamber (20) and the RF generator (10), which may cause a problem in that the power intended to be supplied to the plasma chamber (20) cannot be supplied. To prevent this, it is common to apply an RF matching network (30) between the RF generator (10) and the plasma chamber (20). The RF matching network (30) is a device that varies the impedance by utilizing a circuit that uses an inductor and a capacitor.

[0021] There are two types of impedance matching circuits applied to RF matching networks (30): variable inductor and variable capacitor. The variable inductor method adjusts the inductance of the inductor, but it has the disadvantage of being difficult to control. Due to this disadvantage, the variable capacitor method is mainly used in impedance matching circuits. The variable capacitor method includes vacuum variable capacitor (VVC) and electric variable capacitor (eVC) methods. The vacuum variable capacitor method changes the capacitance by mechanically adjusting the distance between electrodes. However, since a motor is used to adjust the distance between electrodes, it has the disadvantage of slow capacitance variation time. If the capacitance variation time is slow, the semiconductor manufacturing process time is prolonged, which can lead to a decrease in semiconductor yield. Therefore, the electric variable capacitor method, which provides a faster capacitance variation time, is currently being extensively researched.

[0022] FIG. 2 is a circuit diagram of an electrically variable capacitor using a conventional PiN diode (45). As can be seen in FIG. 2, the conventional electrically variable capacitor uses a filter inductor (L) for the stability of the switching operation. f ) using ) regardless of the reverse voltage applied to the diode at high frequency, junction capacitance (C j A PiN diode (45) with a low and constant value (about 3 pF) is used. Junction capacitance refers to the capacitance of a diode when a reverse bias voltage is applied to the diode.

[0023] When the second switch (43) is turned on, the PiN diode (45) remains on due to the bias current, so the total electrical capacitance (C eff ) is the electrical capacitance (C) of the intrinsic capacitor (47). org ) and the electrical capacitance (C) of the variable capacitor (44) var It becomes equal to the sum of ). On the other hand, when the first switch (42) is turned on, a reverse bias voltage is applied to the PiN diode (45), causing it to turn off, and the junction capacitance (Cj ) The electrical capacitance (C) of the variable capacitor (44) var If it is much smaller than ), the total electrical capacitance (C eff ) is the electrical capacitance (C) of the intrinsic capacitor (47). org It becomes approximately the same as ). However, conventional electrically variable capacitors using PiN diodes (45) may have the problem of increased circuit construction costs and slow capacitance variation time.

[0024] FIG. 3 is a circuit diagram of an electrically variable capacitor according to an embodiment of the present disclosure, and FIG. 4 is a conceptual diagram of the operating principle of an electrically variable capacitor according to an embodiment of the present disclosure. Referring to FIG. 3, the electrically variable capacitor according to an embodiment of the present disclosure may include a DC power supply unit (100), a first variable capacitor unit (200), and a second variable capacitor unit (300).

[0025] The DC power supply unit (100) is a power supply device that supplies DC voltage. The DC power supply unit (100) functions to supply reverse bias voltage to the first diode (240) and the second diode (340) of the first variable capacitor unit (200) and the second variable capacitor unit (300), which will be described later. It is preferable for the DC power supply unit (100) to supply a constant voltage. Depending on the application, the voltage of the DC power supply unit (100) may vary, but preferably, it can supply a DC voltage of 650 to 750V, and is not limited thereto.

[0026] The first variable capacitor section (200) and the second variable capacitor section (300) are electrically connected to the DC power supply section (100) and can be connected to each other in a series manner.

[0027] The first variable capacitor section (200) may include a first switch (210), a second switch (220), a first variable capacitor (230), a first diode (240), a first inductor (250), and a third inductor (260).

[0028] The first switch (210) and the second switch (220) are connected to each other in series. In this specification, the term “switch” refers to an electronic device capable of allowing or blocking the flow of current, and may be a transistor, but is not limited thereto as long as it can allow or block the flow of current. The first switch (210) and the second switch (220) may be controlled by a control unit. In this specification, the term “control unit” refers to a processor board comprising at least one CPU (Central Process Unit) and at least one memory. The control unit may be a processor board installed within the RF matching network (30) and configured to vary the impedance of the RF matching network (30) by receiving feedback on the impedance according to the state of the plasma chamber (20).

[0029] The first variable capacitor (230) and the first diode (240) are connected in parallel with the first switch (210) and the second switch (220) and are connected in series with each other. In this specification, the term “variable capacitor” refers to a capacitor having a fixed capacitance for changing the capacitance in the electrically variable capacitor of this disclosure. The capacitance of the first variable capacitor (230) may vary depending on the frequency of the high-frequency RF power supplied from the RF generator. As an example, the first variable capacitor (230) may be a capacitor having a capacitance of several tens of pF, preferably a capacitor having a capacitance in the range of 20 to 30 pF, but is not limited thereto. In this specification, the term “diode” refers to a diode capable of controlling the flow of current according to the direction of the current. The first diode (240) may be a cost-effective and fast-operating PN junction diode or SiC (Schottky) diode, but is not limited thereto.

[0030] The first inductor (250) can electrically connect the middle of the first switch (210) and the second switch (220) and the middle of the first variable capacitor (230) and the first diode (240).

[0031] The third inductor (260) can be connected in parallel with the first variable capacitor (230) and the first diode (240).

[0032] The second variable capacitor section (300) is composed of a circuit having the same structure as the first variable capacitor section (200) described above. The second variable capacitor section (300) may include a third switch (310), a fourth switch (320), a second variable capacitor (330), a second diode (340), a second inductor (350), and a fourth inductor (360).

[0033] The third switch (310) and the fourth switch (320) are connected in series. The third switch (310) and the fourth switch (320) can be controlled by a control unit.

[0034] The second variable capacitor (330) and the second diode (340) are connected in parallel with the third switch (310) and the fourth switch (320) and are connected in series with each other. The capacitance of the second variable capacitor (330) may vary depending on the frequency of the high-frequency RF power supplied from the RF generator. As an example, the second variable capacitor (330) may be a capacitor having a capacitance of several tens of pF, similar to the first variable capacitor (230), and preferably may be a capacitor having a capacitance in the range of 20 to 30 pF, but is not limited thereto. The second diode (340) may be a cost-effective and fast-operating PN junction diode or SiC (Schottky) diode, similar to the first diode (240), but is not limited thereto.

[0035] The second inductor (350) can electrically connect the middle of the third switch (310) and the fourth switch (320) and the middle of the second variable capacitor (330) and the second diode (340).

[0036] The fourth inductor (360) can be connected in parallel with the second variable capacitor (330) and the second diode (340).

[0037] The electrically variable capacitor of the present disclosure may be characterized in that the first diode (240) and the second diode (340) are connected in series in opposite directions to each other.

[0038] The electrically variable capacitor of the present disclosure may further include an intrinsic capacitor (400). In this specification, the term “intrinsic capacitor” refers to a capacitor having a fixed capacitance for changing the capacitance based on a specific capacitance in the electrically variable capacitor of the present disclosure. The intrinsic capacitor (400) is connected in parallel with the first and second variable capacitor sections (200, 300). The intrinsic capacitor (400) may generally be a capacitor having a capacitance of several hundred pF, preferably a capacitor having a capacitance in the range of 200 to 300 pF, but is not limited thereto.

[0039] FIG. 4 illustrates the operating principle of an electrically variable capacitor according to an embodiment of the present disclosure.

[0040] FIG. 4(a) is an equivalent circuit diagram when the second switch (220) of the first variable capacitor section (200) and the fourth switch (320) of the second variable capacitor section (300) are turned on. As previously described, the second switch (220) and the fourth switch (320) can be turned on by the control of the control unit. When the second switch (220) and the fourth switch (320) are turned on, the bias current (I BiasDue to ), the first diode (240) and the second diode (340) remain in a continuously turned-on state. Therefore, the combined electrical capacitance of the first variable capacitor (230) and the second variable capacitor (330) connected in series is It becomes. Here, C var1 is the electrical capacitance of the first variable capacitor (230), and C var2 is the capacitance of the second variable capacitor (330). Therefore, the total capacitance of the equivalent circuit diagram is It becomes. Here, C org is the electrical capacitance of the intrinsic capacitor (400).

[0041] In contrast, FIG. 4(b) is an equivalent circuit diagram when the first switch (210) of the first variable capacitor section (200) and the third switch (310) of the second variable capacitor section (300) are turned on. As previously described, the first switch (210) and the third switch (310) can be turned on by the control of the control unit. When the first switch (210) and the third switch (310) are turned on, a reverse bias voltage is applied to the first diode (240) and the second diode (340), and as a result, the first diode (240) and the second diode (340) remain in a continuously off state. In this case, the first diode (240) and the second diode (340) each have a junction capacitance C j1 , C j2 It has. According to the experiment, when the voltage of the DC power supply (100) is kept constant, the RF voltage (R) of the RF generator (10) RF Even if ) changes, when a reverse bias voltage is applied to the first diode (240) and the second diode (340), the junction capacitance (C) of the first diode (240) and the second diode (340) j1 , C j2 It was confirmed that ) has a constant value. Therefore, the combined electrical capacitance of the junction electrical capacitance of the first variable capacitor (230) and the second variable capacitor (330) and the first diode (240) and the second diode (340) connected in series is ... becomes. Therefore, the total capacitance of the equivalent circuit diagram is It becomes.

[0042] The electrical capacitance (C) of the intrinsic capacitor (400) org ) is several hundred pF, and the electrical capacitance (C) of the first variable capacitor (230) and the second variable capacitor (330) var1 , C var2 ) is several tens of pF, and the junction capacitance (C) of the first diode (240) and the second diode (340) j1 , C j2 If ) is much lower than the previously mentioned capacitances (e.g., about 6 pF), then because the combined capacitance of the junction capacitances of the first variable capacitor (230) and the second variable capacitor (330) and the first diode (240) and the second diode (340) is very small compared to the capacitance of the intrinsic capacitor (400), the total capacitance of the equivalent circuit diagram is C, which is the capacitance of the intrinsic capacitor (400). org It is approximately the same as.

[0043] In this way, by controlling the first switch (210), the second switch (220), the third switch (310), and the fourth switch (32) in the control unit, the electrically variable capacitor of the present disclosure can vary its capacitance, thereby enabling impedance matching of the RF matching network (30).

[0044] FIG. 5 is a circuit diagram of an electrically variable capacitor according to one embodiment of the present disclosure, and FIG. 6 is a conceptual diagram of the operating principle of an electrically variable capacitor according to one embodiment of the present disclosure. Referring to FIG. 5, the electrically variable capacitor of the present disclosure may include a DC power supply unit (100), a first switching circuit unit (500), a second switching circuit unit (600), and a variable capacitor (700). The first switching circuit unit (500) and the second switching circuit unit (500) are electrically connected to the DC power supply unit (100) and may be connected to each other in a series manner.

[0045] As described above, the DC power supply unit (100) is a power supply device that supplies a DC voltage. The DC power supply unit (100) functions to apply a reverse bias voltage to the first diode (540) and the second diode (640) of the first switching circuit unit (500) and the second switching circuit unit (600) to be described later. The DC power supply unit (100) can supply a constant voltage, preferably a DC voltage of 650 to 750V, but is not limited thereto.

[0046] The first switching circuit (500) may include a first switch (510), a second switch (520), a first diode (540), and a first inductor (550).

[0047] The first switch (510) and the second switch (520) are connected to each other in series. The first switch (510) and the second switch (520) can be controlled by a control unit.

[0048] The first diode (540) is connected in parallel with the first switch (510) and the second switch (520). The first diode (540) may be a cost-effective and fast-operating PN junction diode or SiC (Schottky) diode, but is not limited thereto.

[0049] The first inductor (550) electrically connects the first diode (540) to the middle of the first switch (510) and the second switch (520).

[0050] The second switching circuit section (600) is composed of a circuit having the same structure as the first switching circuit section (500) described above. The second switching circuit section (600) may include a third switch (610), a fourth switch (620), a second diode (640), and a second inductor (650).

[0051] The third switch (610) and the fourth switch (620) are connected to each other in series. The third switch (610) and the fourth switch (620) can be controlled by a control unit.

[0052] The second diode (640) is connected in parallel with the third switch (610) and the fourth switch (620). The second diode (640) may be a cost-effective and fast-operating PN junction diode or SiC (Schottky) diode, similar to the first diode (540), but is not limited thereto.

[0053] The second inductor (650) electrically connects the middle of the third switch (610) and the fourth switch (620) to the second diode (640).

[0054] The variable capacitor (700) is connected in series with the first switching circuit (500) and the second switching circuit (600). The variable capacitor (700) may generally be a capacitor having an electrical capacitance of several tens of pF, and preferably may be a capacitor having an electrical capacitance in the range of 20 to 30 pF, but is not limited thereto.

[0055] An electrically variable capacitor according to one embodiment of the present disclosure may be characterized in that a first diode (540) and a second diode (640) are connected in series in opposite directions to each other.

[0056] An electrically variable capacitor according to one embodiment of the present disclosure may further include an intrinsic capacitor (400). The intrinsic capacitor (400) is connected in parallel with the variable capacitor (700). As described above, the intrinsic capacitor (400) may generally be a capacitor having an electrical capacitance of several hundred pF, and preferably may be a capacitor having an electrical capacitance in the range of 200 to 300 pF, but is not limited thereto.

[0057] FIG. 6 illustrates the operating principle of an electrically variable capacitor according to one embodiment of the present disclosure.

[0058] FIG. 6(a) is an equivalent circuit diagram when the second switch (520) of the first switching circuit unit (500) and the fourth switch (620) of the second switching circuit unit (600) are turned on. As previously described, the second switch (520) and the fourth switch (620) can be turned on by the control of the control unit. When the second switch (520) and the fourth switch (620) are turned on, the bias current (I Bias Due to ), the first diode (540) and the second diode (640) remain in a continuously turned-on state. Therefore, since the intrinsic capacitor (400) and the variable capacitor (700) are connected in parallel, the total electrical capacitance is the electrical capacitance (C) of the intrinsic capacitor (400). org ) and the electrical capacitance (C) of the variable capacitor (700) var The sum of ) It becomes.

[0059] In contrast, FIG. 4(b) is an equivalent circuit diagram when the first switch (510) of the first switching circuit unit (500) and the third switch (610) of the second switching circuit unit (600) are turned on. As previously described, the first switch (510) and the third switch (610) can be turned on by the control of the control unit. When the first switch (510) and the third switch (610) are turned on, a reverse bias voltage is applied to the first diode (540) and the second diode (640), and as a result, the first diode (540) and the second diode (640) remain in a continuously off state. In this case, the first diode (540) and the second diode (640) each have a junction capacitance C j1 , C j2 It has. As mentioned above, according to the experiment, when the voltage of the DC power supply (100) is kept constant, the RF voltage (R) of the RF generator (10) RF Even if ) changes, when a reverse bias voltage is applied to the first diode (540) and the second diode (640), the junction capacitance (C) of the first diode (540) and the second diode (640) j1 , C j2It was confirmed that ) has a constant value. Therefore, the combined electrical capacitance of the junction electrical capacitance of the variable capacitor (700), the first diode (540), and the second diode (640) connected in series is ... becomes. Therefore, the total capacitance of the equivalent circuit diagram is It becomes.

[0060] The electrical capacitance (C) of the intrinsic capacitor (400) org ) is several hundred pF, and the electrical capacitance (C) of the variable capacitor (700) var ) is several tens of pF, and the junction capacitance (C) of the first diode (540) and the second diode (640) j1 , C j2 If ) is much lower than the previously mentioned capacitances (e.g., about 6 pF), then because the combined capacitance of the variable capacitor (700), the first diode (540), and the second diode (640) is very small compared to the capacitance of the intrinsic capacitor (400), the total capacitance of the equivalent circuit diagram is C, which is the capacitance of the intrinsic capacitor (400). org It is approximately the same as.

[0061] In this way, by controlling the first switch (510), the second switch (520), the third switch (610), and the fourth switch (620) in the control unit, the electrically variable capacitor of the present disclosure can vary its capacitance, thereby enabling impedance matching of the RF matching network (30).

[0062] FIG. 7 is a circuit diagram of an electrically variable capacitor according to another embodiment of the present disclosure, and FIG. 8 is a conceptual diagram of the operating principle of an electrically variable capacitor according to another embodiment of the present disclosure. Referring to FIG. 7, the electrically variable capacitor of the present disclosure may include a first DC power variable capacitor section (800) and a second DC power variable capacitor section (900). The first DC power variable capacitor section (800) and the second DC power variable capacitor section (900) may be connected to each other in series.

[0063] The first DC power variable capacitor section (800) may include a first DC power section (802), a first switch (810), a second switch (820), a first variable capacitor (830), a first diode (840), a first inductor (850), and a third inductor (860).

[0064] The first DC power supply unit (802) is a power supply device that supplies a DC voltage. The first DC power supply unit (802) functions to supply a reverse bias voltage to the first diode (840) to be described later. It is preferable for the first DC power supply unit (802) to supply a constant voltage. Depending on the application, the voltage of the first DC power supply unit (802) may vary, but preferably, it can supply a DC voltage of 650 to 750V, and is not limited thereto.

[0065] The first switch (810) and the second switch (820) are electrically connected to the first DC power supply (802) and are connected to each other in series. The first switch (810) and the second switch (820) can be controlled by a control unit.

[0066] The first variable capacitor (830) and the first diode (840) are connected in parallel with the first switch (810) and the second switch (820) and are connected in series with each other. The first variable capacitor (830) may generally be a capacitor having a capacitance of several tens of pF, preferably a capacitor having a capacitance in the range of 20 to 30 pF, but is not limited thereto. The first diode (840) may be a cost-effective and fast-operating PN junction diode or SiC (Schottky) diode, but is not limited thereto.

[0067] The first inductor (850) can electrically connect the middle of the first switch (810) and the second switch (820) and the middle of the first variable capacitor (830) and the first diode (840).

[0068] The third inductor (860) can be connected in parallel with the first variable capacitor (830) and the first diode (840).

[0069] The second DC power variable capacitor section (900) has a circuit with the same structure as the first DC power variable capacitor section (800) described above, and may include a second DC power section (902), a third switch (910), a fourth switch (920), a second variable capacitor (930), a second diode (940), a second inductor (950), and a fourth inductor (960).

[0070] The second DC power supply unit (802) is a power supply device that supplies DC voltage. The second DC power supply unit (902) functions to supply reverse bias voltage to the second diode (940) to be described later. It is preferable for the second DC power supply unit (902) to supply a constant voltage. Depending on the application, the voltage of the second DC power supply unit (902) may vary, but preferably, it can supply a DC voltage of 650 to 750V, and is not limited thereto.

[0071] The third switch (910) and the fourth switch (920) are electrically connected to the second DC power supply (902) and are connected to each other in series. The third switch (910) and the fourth switch (920) can be controlled by a control unit.

[0072] The second variable capacitor (930) and the second diode (940) are connected in parallel with the third switch (910) and the fourth switch (920) and are connected in series with each other. The second variable capacitor (930) may be a capacitor having a capacitance of several tens of pF, similar to the first variable capacitor (830), preferably a capacitor having a capacitance in the range of 20 to 30 pF, but is not limited thereto. The second diode (940) may be a cost-effective and fast-operating PN junction diode or SiC (Schottky) diode, similar to the first diode (840), but is not limited thereto.

[0073] The second inductor (950) can electrically connect the middle of the third switch (910) and the fourth switch (920) and the middle of the second variable capacitor (930) and the second diode (940).

[0074] The third inductor (960) can be connected in parallel with the second variable capacitor (930) and the second diode (940).

[0075] An electrically variable capacitor according to another embodiment of the present disclosure may further include a intrinsic capacitor (400). The intrinsic capacitor (400) is connected in parallel with the first DC power variable capacitor section (800) and the second DC power variable capacitor section (800). As described above, the intrinsic capacitor (400) may be a capacitor having an electrical capacitance of several hundred pF, preferably a capacitor having an electrical capacitance in the range of 200 to 300 pF, but is not limited thereto.

[0076] FIG. 8 illustrates the operating principle of an electrically variable capacitor according to another embodiment of the present disclosure. Since the operating principle of the electrically variable capacitor according to another embodiment of the present disclosure is the same as the operating principle of the electrically variable capacitor according to the embodiment of the present disclosure of FIG. 3, a detailed description is omitted here.

[0077] FIG. 9 is a circuit diagram of an electrically variable capacitor according to another embodiment of the present disclosure, and FIG. 10 is a conceptual diagram of the operating principle of an electrically variable capacitor according to another embodiment of the present disclosure. Referring to FIG. 9, the electrically variable capacitor of the present disclosure includes a first DC power switching circuit section (1000), a second DC power switching circuit section (1100), and a variable capacitor (700). The first DC power switching circuit section (1000) and the second DC power switching circuit section (1100) are connected to each other in series.

[0078] The first DC power switching circuit (1000) may include a first DC power supply (1002), a first switch (1010), a second switch (1020), a first diode (1040), and a first inductor (1050).

[0079] The first DC power supply unit (1002) is a power supply device that supplies a DC voltage. The first DC power supply unit (1002) functions to supply a reverse bias voltage to the first diode (1040) to be described later. It is preferable for the first DC power supply unit (1002) to supply a constant voltage. Depending on the application, the voltage of the first DC power supply unit (1002) may vary, but preferably, it can supply a DC voltage of 650 to 750V, and is not limited thereto.

[0080] The first switch (1010) and the second switch (1020) are electrically connected to the first DC power supply (1002) and are connected to each other in series. The first switch (1010) and the second switch (1020) can be controlled by a control unit.

[0081] The first diode (1040) is connected in parallel with the first switch (1010) and the second switch (1020). The first diode (1040) may be a cost-effective and fast-operating PN junction diode or SiC (Schottky) diode, but is not limited thereto.

[0082] The first inductor (1050) electrically connects the middle of the first switch (1010) and the second switch (1020) to the first diode (1040).

[0083] The second DC power switching circuit (1100) is composed of a circuit having the same structure as the first DC power switching circuit (1000) described above. The second DC power switching circuit (1100) may include a second DC power supply (1102), a second switch (1110), a third switch (1120), a second diode (1140), and a second inductor (1150).

[0084] The second DC power supply unit (1102) is a power supply device that supplies DC voltage. The second DC power supply unit (1102) functions to supply reverse bias voltage to the second diode (1140) to be described later. It is preferable for the second DC power supply unit (1102) to supply a constant voltage. Depending on the application, the voltage of the second DC power supply unit (1102) may vary, but preferably, it can supply a DC voltage of 650 to 750V, and is not limited thereto.

[0085] The third switch (1110) and the fourth switch (1120) are electrically connected to the second DC power supply (1102) and are connected to each other in series. The third switch (1110) and the fourth switch (1120) can be controlled by a control unit.

[0086] The second diode (1140) is connected in parallel with the third switch (1110) and the fourth switch (1120). The second diode (1140) may be a cost-effective and fast-operating PN junction diode or SiC (Schottky) diode, similar to the first diode (1040), but is not limited thereto.

[0087] The second inductor (1150) electrically connects the middle of the third switch (1110) and the fourth switch (1120) with the second diode (1140).

[0088] The variable capacitor (700) is connected in series with the first DC power switching circuit (1000) and the second DC power switching circuit (1100). The variable capacitor (700) may be a capacitor having an electrical capacitance of several tens of pF, preferably a capacitor having an electrical capacitance in the range of 20 to 30 pF, but is not limited thereto.

[0089] An electrically variable capacitor according to another embodiment of the present disclosure may further include an intrinsic capacitor (400). The intrinsic capacitor (400) is connected in parallel with the variable capacitor (700). The intrinsic capacitor (400) may be a capacitor having an electrical capacitance of several hundred pF, preferably a capacitor having an electrical capacitance in the range of 200 to 300 pF, but is not limited thereto.

[0090] FIG. 10 illustrates the operating principle of an electrically variable capacitor according to another embodiment of the present disclosure. Since the operating principle of the electrically variable capacitor according to another embodiment of the present disclosure is the same as the operating principle of the electrically variable capacitor according to one embodiment of the present disclosure in FIG. 5, a detailed description is omitted here.

[0092] The disclosed content is merely illustrative and can be modified and implemented in various ways by a person skilled in the art without departing from the gist of the claim in the patent claims; therefore, the scope of protection of the disclosed content is not limited to the specific embodiments described above. Explanation of the symbols

[0093] 10: RF generator 20: Plasma chamber 30: RF Matching Network 41: DC power supply 42: First switch 43: Second switch 44: Variable capacitor 45: PiN diode 46: Inductor 47: Intrinsic capacitor 100: DC power supply 200: 1st variable capacitor section 210: 1st switch 220: Second switch 230: First variable capacitor 240: First diode 250: First inductor 260: Third inductor 300: Second variable capacitor section 310: Third switch 320: 4th switch 330: Second variable capacitor 340: Second diode 350: Second inductor 360: 4th inductor 400: intrinsic capacitor 500: 1st switching circuit section 510: 1st switch 520: Second switch 540: First diode 550: First inductor 600: Second switching circuit section 610: Third switch 620: 4th switch 640: Second diode 650: Second inductor 700: Variable capacitor 800: 1st DC power variable capacitor section 802: 1st DC Power Supply 810: 1st switch 820: Second switch 830: First variable capacitor 840: First diode 850: First inductor 860: Third inductor 900: 2nd DC power variable capacitor section 902: 2nd DC Power Supply 910: Third switch 920: 4th switch 930: Second variable capacitor 940: Second diode 950: Second inductor 960: 4th inductor 1000: 1st DC power switching circuit section 1002: 1st DC Power Supply 1010: 1st switch 1020: Second switch 1040: First diode 1050: First inductor 1100: 2nd DC power switching circuit section 1102: 2nd DC Power Supply 1110: 3rd switch 1120: 4th switch 1140: Second diode 1150: Second inductor

Claims

Claim 1 An electrically variable capacitor used in an RF matching network (30) comprises: a DC power supply unit (100); and a first variable capacitor unit (200) and a second variable capacitor unit (300) that are electrically connected to the DC power supply unit (100) and connected to each other in a series manner; wherein the first variable capacitor unit (200) comprises a first switch (210) and a second switch (220) that are connected to each other in a series manner; a first variable capacitor (230) and a first diode (240) that are connected in parallel with the first and second switches (210, 220) and connected to each other in a series manner; and a first inductor (250) that electrically connects the middle of the first and second switches (210, 220) and the middle of the first variable capacitor (230) and the first diode (240). The electrical variable capacitor comprises: a third inductor (260) connected in parallel with the first variable capacitor (230) and the first diode (240); and the second variable capacitor section (300) comprises a third switch (310) and a fourth switch (320) connected in series with each other; a second variable capacitor (330) and a second diode (340) connected in parallel with the third and fourth switches (310, 320) and connected in series with each other; a second inductor (350) electrically connecting the middle of the third and fourth switches (310, 320) and the middle of the second variable capacitor (330) and the second diode (340); and a fourth inductor (360) connected in parallel with the second variable capacitor (330) and the second diode (340). Claim 2 An electrical variable capacitor according to claim 1, further comprising a unique capacitor (400) connected in parallel with the first and second variable capacitor sections (200, 300). Claim 3 An electrically variable capacitor according to claim 1, characterized in that the voltage of the DC power supply (100) is a voltage of a constant magnitude. Claim 4 An electrically variable capacitor according to claim 1, wherein the first and second diodes (240, 340) are PN junction diodes or SiC (Schottky) diodes. Claim 5 An electrically variable capacitor according to claim 1, characterized in that the first and second diodes (240, 340) are connected in series in opposite directions. Claim 6 An electrically variable capacitor used in an RF matching network (30) comprises: a DC power supply (100); a first switching circuit (500) and a second switching circuit (600) electrically connected to the DC power supply (100) and connected to each other in a series manner; and a variable capacitor (700) connected in a series manner to the first and second switching circuits (500, 600); wherein the first switching circuit (500) comprises a first switch (510) and a second switch (520) connected to each other in a series manner; and a first diode (540) connected in a parallel manner to the first and second switches (510, 520). An electrically variable capacitor comprising: a first inductor (550) electrically connecting the middle of the first and second switches (510, 520) and the first diode (540); and the second switching circuit part (600) comprising: a third switch (610) and a fourth switch (620) connected in series with each other; a second diode (640) connected in parallel with the third and fourth switches (610, 620); and a second inductor (650) electrically connecting the middle of the third and fourth switches (610, 620) and the second diode (640). Claim 7 In claim 6, An electrical variable capacitor characterized by further including a intrinsic capacitor (400) connected in parallel with the variable capacitor (700) above. Claim 8 An electrically variable capacitor according to claim 6, characterized in that the voltage of the DC power supply (100) is a voltage of a constant magnitude. Claim 9 An electrically variable capacitor according to claim 7, wherein the first and second diodes (540, 640) are PN junction diodes or SiC (Schottky) diodes. Claim 10 An electrically variable capacitor according to claim 7, characterized in that the first and second diodes (540, 640) are connected in series in opposite directions. Claim 11 An electrically variable capacitor used in an RF matching network (30) comprises a first DC power variable capacitor section (800) and a second DC power variable capacitor section (900) connected in series with each other, wherein the first DC power variable capacitor section (800) comprises: a first DC power section (802); a first switch (810) and a second switch (820) electrically connected to the first DC power section and connected in series with each other; a first variable capacitor (830) and a first diode (840) connected in parallel with the first and second switches (810, 820); and a first inductor (850) electrically connecting the middle of the first and second switches (810, 820) and the middle of the first variable capacitor (830) and the first diode (840). and a third inductor (860) connected in parallel with the first variable capacitor (830) and the first diode (840); and the second DC power variable capacitor section (900) comprises a second DC power section (902); a third switch (910) and a fourth switch (920) electrically connected to the second DC power section (902) and connected in series with each other; a second variable capacitor (930) and a second diode (940) connected in parallel with the third and fourth switches (910, 920); and a second inductor (950) electrically connecting the middle of the third and fourth switches (910, 920) and the middle of the second variable capacitor (930) and the second diode (940). An electrically variable capacitor comprising: a fourth inductor (960) connected in parallel with the second variable capacitor (930) and the second diode (940). Claim 12 An electrical variable capacitor according to claim 11, further comprising a unique capacitor (400) connected in parallel with the first and second DC power variable capacitor sections (800, 900). Claim 13 An electrically variable capacitor according to claim 11, characterized in that the voltage of the first and second DC power supply units (802, 902) is a voltage of a constant magnitude. Claim 14 An electrically variable capacitor according to claim 11, wherein the first and second diodes (840, 940) are PN junction diodes or SiC (Schottky) diodes. Claim 15 An electrically variable capacitor used in an RF matching network (30) comprises: a first DC power switching circuit section (1000) and a second DC power switching circuit section (1100) connected in series with each other; and a variable capacitor (700) connected in series with the first and second DC power switching circuit sections (1000, 1100); wherein the first DC power switching circuit section (1000) comprises: a first DC power section (1002); a first switch (1010) and a second switch (1020) electrically connected to the first DC power section (1002) and connected in series with each other; and a first diode (1040) connected in parallel with the first and second switches (1010, 1020). The electrical variable capacitor comprises: a first inductor (1050) electrically connecting the middle of the first and second switches (1010, 1020) and the first diode (1040); and the second DC power switching circuit (1100) comprises: a second DC power supply unit (1102); a third switch (1110) and a fourth switch (1120) electrically connected to the second DC power supply unit (1102) and connected to each other in a series manner; a second diode (1140) connected in a parallel manner to the third and fourth switches (1110, 1120); and a second inductor (1150) electrically connecting the middle of the third and fourth switches (1110, 1120) and the second diode (1140). Claim 16 An electrical variable capacitor according to claim 15, further comprising a intrinsic capacitor (400) connected in parallel with the variable capacitor (700). Claim 17 An electrically variable capacitor according to claim 15, characterized in that the voltage of the first and second DC power supply units (1002, 1102) is a voltage of a constant magnitude. Claim 18 An electrically variable capacitor according to claim 15, wherein the first and second diodes (1040, 1140) are PN junction diodes or SiC (Schottky) diodes.

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