Power transfer device for coupling RF power and DC pulse voltage and transferring same to load

Abstract

A power transfer device according to an embodiment of the present invention includes: an impedance matching network for transferring RF power of an RF generator to a load; a band stop filter for transferring a DC pulse voltage of a DC pulse generator to the load and suppressing the RF power from being transferred to the DC pulse generator; a DC blocking capacitor connected to an output terminal of the impedance matching network to suppress the DC pulse voltage from being transferred to the impedance matching network through an output terminal of the band stop filter; and an impedance transformer connected to the output terminal of the band stop filter to change the impedance of the RF power incident on the band stop filter. The output terminal of the impedance transformer and the output terminal of the DC blocking capacitor are connected to each other and then connected to the load through a transmission line.

Description

A power transmission device that combines RF power and DC pulse voltage and delivers them to a load.

[0001] The present invention relates to a semiconductor device manufacturing apparatus, and more particularly, to a device for delivering RF power and DC pulse voltage to form plasma in a plasma process chamber used in semiconductor manufacturing.

[0002] Plasma etching equipment utilizes a combination of high-frequency RF source power for plasma generation and low-frequency RF bias power to control the ion energy incident on the substrate. Typically, the RF source power frequency is above 3 MHz to achieve high plasma density. Meanwhile, the RF bias power frequency is relatively low, below 3 MHz.

[0003] In plasma etching processes driven by semiconductor device miniaturization technology, issues such as etch uniformity, etch selectivity, and anisotropic etching characteristics continue to arise. To address these issues, RF pulse waves, which periodically modulate RF power instead of continuous waves, are being used.

[0004] Figures 1 and 2 are drawings explaining a conventional power transmission structure.

[0005] Referring to FIGS. 1 and 2, U.S. registered patent US 11462389 B2 proposed a technique of using a DC pulse bias instead of an RF bias power. In this plasma etching device (10), a DC pulse bias of a DC pulse generator (21) is applied to a first electrode (or electrostatic electrode, 24) disposed on a substrate holder (30), and an RF source power of an RF generator (11) is applied to a second electrode (14) disposed below the first electrode (24). The first electrode (24) and the second electrode (14) form a base capacitor (Cbase) with a dielectric therebetween. The DC pulse generator (21) applies a DC pulse bias to the first electrode through a band stop filter (22) and a power line (23). The RF generator (11) applies RF power to the second electrode (14) through an impedance matching network (12) and a power line (13).

[0006] However, as the voltage of the DC pulse bias increases from several kV to several tens of kV, a high voltage is applied between the first electrode (24) and the second electrode (14), and the substrate holder (30) is damaged due to phenomena such as insulation breakdown or abnormal discharge of the base capacitor (Cbase). Therefore, a new power transmission method capable of suppressing damage to the substrate holder (30) is required.

[0007] The technical problem to be solved by the present invention is to provide a power transmission device that suppresses insulation breakdown or abnormal discharge between a first electrode to which a DC voltage is applied and a second electrode to which RF power is applied, which are mounted on a substrate holder.

[0008] The technical problem to be solved by the present invention is to provide a substrate processing device that integrates an electrode to which a DC pulse voltage and an RF power are applied, which are mounted on a substrate holder, and places a blocking capacitor within an impedance matching network.

[0009] The technical problem to be solved by the present invention is to provide a power transmission device including a band stop filter including an impedance converter that suppresses RF power of an RF generator from being transmitted to a DC pulse generator side through an impedance matching network.

[0010] The technical problem to be solved by the present invention is to provide an impedance matching network that transmits RF power of an RF generator to a load and a band stop filter that transmits DC pulse voltage of a DC pulse generator to a load while preventing the RF power from flowing into the DC pulse generator.

[0011] The technical problem to be solved by the present invention is to provide a band stop filter that transmits the DC pulse voltage of a DC pulse generator to a load while suppressing overshoot and prevents the RF power of an RF generator from flowing into the DC pulse generator.

[0012] A power transmission device according to one embodiment of the present invention includes: an impedance matching network for transmitting RF power of an RF generator to a load; a band stop filter for transmitting a DC pulse voltage of a DC pulse generator to a load and suppressing the RF power from being transmitted to the DC pulse generator; a DC blocking capacitor connected to an output terminal of the impedance matching network for suppressing the DC pulse voltage through an output terminal of the band stop filter from being transmitted to the impedance matching network; and an impedance converter connected to an output terminal of the band stop filter for changing an impedance of the RF power incident on the band stop filter. An output terminal of the impedance converter and an output terminal of the DC blocking capacitor are connected to each other and then connected to the load through a transmission line.

[0013] In one embodiment of the present invention, the DC blocking capacitor is disposed inside the impedance matching network, and the DC blocking capacitor may be a high-voltage vacuum capacitor or a high-voltage ceramic capacitor.

[0014] In one embodiment of the present invention, the DC blocking capacitor may be replaceable.

[0015] In one embodiment of the present invention, the DC blocking capacitors are plural and connected in series to increase the withstand voltage.

[0016] In one embodiment of the present invention, the impedance transformer is disposed inside the band stop filter, the impedance transformer is an inductor, and the reactance of the inductor may be 25 ohms to 500 ohms.

[0017] In one embodiment of the present invention, the load may include an electrode, a dielectric disposed on the electrode, a substrate disposed on the dielectric, and plasma formed on the substrate.

[0018] In one embodiment of the present invention, the absolute value of the reactance of the impedance converter may be greater than or equal to the absolute value of the reactance of the load.

[0019] In one embodiment of the present invention, the band stop filter may be a pie-type band stop filter having three or more stages.

[0020] In one embodiment of the present invention, the band stop filter includes a series resonator including an inductor and a capacitor connected in parallel with each other, and the reactance of the inductor of the series resonator may be 200 ohms or less.

[0021] In one embodiment of the present invention, the band stop filter may include a shunt resonator including an inductor and a capacitor connected in series with each other. The shunt resonator may be connected to ground.

[0022] In one embodiment of the present invention, the RF generator is a frequency variable RF generator, the band stop filter is a pi-type band stop filter having three or more stages, and the band stop filter may include a series resonator including an inductor and a variable capacitor connected in parallel. The variable capacitor of the series resonator may be variable according to a driving frequency of the RF generator, and a capacitance of the variable capacitor may be variable such that the resonant frequency of the series resonator matches the driving frequency of the RF generator.

[0023] In one embodiment of the present invention, the device may further include an RF sensor positioned between the band stop filter and the DC pulse generator; and a control unit configured to receive an output signal from the RF sensor and calculate RF transmission power. The control unit may provide an interrupt signal to the RF generator when the RF transmission power is greater than or equal to a threshold value.

[0024] In one embodiment of the present invention, the band stop filter is a pie-type band stop filter having three or more stages, and the band stop filter may include a first shunt resonator including a series-connected inductor and a fixed capacitor.

[0025] According to one embodiment of the present invention, a plasma substrate processing device includes: a substrate holder including an electrode supporting a substrate and a dielectric disposed on the electrode; a chamber disposed to surround the substrate holder; an RF generator providing RF power to the electrode to generate plasma on the substrate; a DC pulse generator providing a DC pulse voltage to the electrode; and a power transmission unit transmitting the RF power and the DC pulse voltage to the electrode. The power transmission unit includes an impedance matching network transmitting the RF power of the RF generator to the electrode; a band stop filter transmitting the DC pulse voltage of the DC pulse generator to the electrode and suppressing the RF power from being transmitted to the DC pulse generator; a DC blocking capacitor connected to an output terminal of the impedance matching network to suppress a DC pulse through an output terminal of the band stop filter from being transmitted to the impedance matching network; and an impedance converter connected to an output terminal of the band stop filter to change an impedance of the band stop filter. The output terminal of the above impedance converter and the output terminal of the above DC blocking capacitor are connected to each other and then connected to the electrode through a transmission line.

[0026] In one embodiment of the present invention, the DC blocking capacitor is disposed inside the impedance matching network, and the DC blocking capacitor may be a high-voltage vacuum capacitor or a high-voltage ceramic capacitor.

[0027] In one embodiment of the present invention, the DC blocking capacitor may be replaceable.

[0028] In one embodiment of the present invention, the DC blocking capacitors are plural and connected in series to increase the withstand voltage.

[0029] In one embodiment of the present invention, the impedance transformer is disposed inside the band stop filter, the impedance transformer is an inductor, and the reactance of the inductor may be 25 ohms to 500 ohms.

[0030] In one embodiment of the present invention, the absolute value of the reactance of the impedance converter may be greater than or equal to the absolute value of the reactance of the load.

[0031] A power transmission device according to one embodiment of the present invention comprises: an impedance matching network for transmitting RF power of an RF generator to a load; a band stop filter for transmitting a DC pulse voltage of a DC pulse generator to a load and suppressing the RF power from being transmitted to the DC pulse generator; a DC blocking capacitor connected to an output terminal of the impedance matching network for suppressing a DC pulse voltage through an output terminal of the band stop filter from being transmitted to the impedance matching network; and an output terminal of the band stop filter and an output terminal of the DC blocking capacitor are connected to each other and then connected to the load through a transmission line.

[0032] A power transmission device according to one embodiment of the present invention suppresses insulation breakdown or abnormal discharge between a first electrode to which a DC voltage is applied and a second electrode to which RF power is applied, which are mounted on a substrate holder.

[0033] A power transmission device according to one embodiment of the present invention can provide a compact power transmission structure by integrating a DC pulse voltage and an RF power-applied electrode mounted on a substrate holder into one, and arranging a blocking capacitor within an impedance matching network.

[0034] A power transmission device according to one embodiment of the present invention may provide a band stop filter including an impedance converter that suppresses RF power of an RF generator from being transmitted to a DC pulse generator side through an impedance matching network.

[0035] A power transmission device according to one embodiment of the present invention may provide an impedance matching network that transmits RF power of an RF generator to a load and a band stop filter that transmits a DC pulse voltage of a DC pulse generator to the load while preventing the RF power from flowing into the DC pulse generator.

[0036] A power transmission device according to one embodiment of the present invention can provide a band stop filter that transmits a DC pulse voltage of a DC pulse generator to a load while suppressing overshoot and prevents RF power of an RF generator from flowing into the DC pulse generator.

[0037] Figures 1 and 2 are drawings explaining a conventional power transmission structure.

[0038] FIG. 3 is a conceptual diagram illustrating a plasma substrate processing device and a power transmission device according to one embodiment of the present invention.

[0039] Fig. 4 is a circuit diagram illustrating the plasma substrate processing device and power transmission device of Fig. 3.

[0040] FIG. 5 is a drawing showing the connection relationship of a blocking capacitor according to another embodiment of the present invention.

[0041] FIG. 6 is a diagram showing impedance when viewed in the direction of a power transmission unit in the load direction according to one embodiment of the present invention.

[0042] Figure 7 shows the impedance change when an impedance converter is added to the power transmission unit.

[0043] FIG. 8 is a simulation result showing the operating range of an impedance matching network according to the reactance of an impedance converter according to one embodiment of the present invention.

[0044] FIG. 9a and FIG. 9b show the transmission characteristics of a band stop filter according to the inductance of an impedance converter according to one embodiment of the present invention.

[0045] FIGS. 10A and 10B illustrate the operating range of an impedance matching network when a band stop filter is removed from a power transmission device according to one embodiment of the present invention.

[0046] FIGS. 11a to 11c illustrate the operating range of an impedance matching network when a band stop filter is included in a power transmission device according to one embodiment of the present invention.

[0047] FIGS. 12A to 12C are drawings showing the characteristics of a band stop filter according to one embodiment of the present invention.

[0048] FIGS. 13a to 13e are drawings showing the characteristics of a band stop filter according to one embodiment of the present invention.

[0049] Fig. 14 is a simulation result showing overshoot according to a series inductor in a band stop filter of a power transmission device according to one embodiment of the present invention.

[0050] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided so that the disclosed content can be thorough and complete, and so that the spirit of the present invention can be sufficiently conveyed to those skilled in the art. In the drawings, components are exaggerated for clarity. Parts denoted by the same reference numerals throughout the specification represent the same components. Figure 3 is a conceptual diagram illustrating a plasma substrate processing device and a power transmission device according to an embodiment of the present invention.

[0051] FIG. 3 is a conceptual diagram illustrating a plasma substrate processing device and a power transmission device according to one embodiment of the present invention.

[0052] Fig. 4 is a circuit diagram illustrating the plasma substrate processing device and power transmission device of Fig. 3.

[0053] Referring to FIGS. 3 and 4, a plasma substrate processing device (100) according to one embodiment of the present invention includes a substrate holder (130), a chamber (101), an RF generator (111), and a power transmission unit (130).

[0054] The plasma substrate processing device (100) may be a plasma etching device. The chamber (101) may be a cylindrical chamber or a square chamber made of a metal material. The chamber (101) may further include a vacuum system and a gas injection system. The chamber (101) may maintain a low pressure (several hundred milliTorr to several milliTorr) for plasma formation. The plasma substrate processing device (100) may anisotropically etch a silicon oxide film or a silicon nitride film on a substrate. The chamber (101) may be arranged to surround the substrate holder (130).

[0055] The substrate may be a semiconductor substrate. The semiconductor substrate may be a silicon substrate on which semiconductor elements are formed.

[0056] A substrate holder (130) may support a substrate and include an electrode (124) and a dielectric (125) disposed on the electrode (124). The substrate holder (130) may be disposed inside the chamber (101). The electrode (124) may be supplied with RF power and DC pulse voltage. The electrode (124) may also function as an electrostatic electrode of an electrostatic chuck.

[0057] An RF generator (111) can provide RF power to the electrode (124) to generate plasma on the substrate. The RF generator (111) can generate a sine wave. The driving frequency of the RF generator (111) can be several tens of MHz or more. The RF power of the RF generator (111) can be transmitted to the electrode (124) to form plasma on the substrate.

[0058] A DC pulse generator (121) can output a DC pulse voltage. The DC pulse voltage may be a bipolar voltage waveform. The DC pulse voltage may have a positive voltage and a negative voltage with a constant cycle. In addition, in a section where the negative voltage is applied, the voltage waveform may have a slope voltage in which the negative voltage decreases over time. The DC pulse voltage may form an electric field between the electrode (124) and the substrate to provide an electrostatic force to adsorb the substrate. The DC pulse voltage may form a strong electric field in a plasma sheath existing between the substrate and the plasma, and may provide a bias voltage so that ions of the plasma are accelerated by the electric field of the plasma sheath and incident on the substrate. The energy of the ions may improve anisotropic etching characteristics of the substrate.

[0059] The power transmission unit (130) transmits the RF power and the DC pulse voltage to the electrode (124). The power transmission unit (130) combines the RF power and the DC pulse voltage to transmit power to the electrode (124). The DC pulse voltage is mainly applied to the blocking capacitor (133) and the substrate capacitor (Cs) between the electrode (124) and the substrate. The blocking capacitor (133) is not installed inside the substrate holder (130) but is arranged in the impedance matching network (132). Therefore, when the DC pulse voltage of several kV to several tens of kV is applied to the blocking capacitor (133), the blocking capacitor (133) can provide stable operation without abnormal operation such as insulation breakdown by using a high-voltage vacuum capacitor. The RF power and the DC pulse voltage are combined and applied to the electrode (124) through a single transmission line (113). Meanwhile, when using multiple transmission lines or power lines, the multiple transmission lines or power lines may cause abnormal operation within the chamber or the substrate holder. Therefore, by using a single transmission line (113), abnormal operation is reduced, thereby improving operational stability.

[0060] The power transmission unit (130) may include an impedance matching network (132), a band stop filter (134), a DC blocking capacitor (132), and an impedance converter (135).

[0061] An impedance matching network (132) transmits the RF power of the RF generator (111) to the electrode (124). The impedance matching network (132) may be an L-type, an inverted L-type, a T-type, or a Pi-type. The impedance matching network (132) may include at least two variable reactive elements. The variable reactive elements may be vacuum variable capacitors.

[0062] For example, the impedance matching network (132) includes a first variable capacitor (C1) and a second variable capacitor (C2) connected to an output terminal of an RF generator. One end of the first variable capacitor (C1) is connected to an output terminal of the RF generator (111), and the other end of the first variable capacitor (C2) can be connected in series with a first inductor (L1) and then connected to ground. One end of the second variable capacitor (C2) is connected to an output terminal of the RF generator (111), and the other end of the second variable capacitor (C2) is connected to one end of a second inductor (L2) and one end of a third inductor (L3). The other end of the second inductor (L2) is grounded. The other end of the third inductor (L3) is connected to an output terminal of the impedance matching network (132).

[0063] A DC blocking capacitor (133) is connected to the output terminal of the impedance matching network (132) to suppress a DC pulse through the output terminal of the band stop filter (134) from being transmitted to the impedance matching network (132). The DC blocking capacitor (133) is arranged inside the impedance matching network (132), and the DC blocking capacitor (133) may be a high-voltage vacuum capacitor or a high-voltage ceramic capacitor. The DC blocking capacitor (133) is a separate component separated from the substrate holder (130), and the DC blocking capacitor (133) is replaceable. In particular, when the DC blocking capacitor (133) is damaged by a DC pulse voltage, the DC blocking capacitor (133) can be easily replaced. The DC blocking capacitors (133) are a plurality (C4, C5) and are connected in series to increase the withstand voltage.

[0064] The band stop filter (134) transmits the DC pulse voltage of the DC pulse generator (121) to the electrode (124) and suppresses the RF power from being transmitted to the DC pulse generator (121). The band stop filter (134) may be a pi-type band stop filter having three or more stages. When the band stop filter (134) is a pi-type band stop filter having three stages, it may include a first stage resonator (134a), a second stage resonator (134b), and a third stage resonator (134c). The first stage resonator (134a) may include an inductor (La) and a capacitor (Ca) connected in series with each other. The second stage resonator (134b) may include an inductor (Lb) and a capacitor (Cb) connected in parallel with each other. The third stage resonator (134c) may include an inductor (Lc) and a capacitor (Cc) that are connected in series with each other. The resonant frequencies of the first to third stage resonators (134a, 134b, 134c) may match the driving frequency of the RF power. The third stage resonator (134c) may be connected to the output terminal of the DC pulse generator (121). One end of the second stage resonator (134b) may be connected to the output terminal of the DC pulse generator (121). The first stage resonator (134a) may be connected to the other end of the second stage resonator (134b). The first stage resonator (134a) and the third stage resonator (134c) may be shunt resonators. The second resonator (134b) may be a series resonator. The above band stop filter (134) can suppress RF power from proceeding toward the DC pulse generator (121) and maintain RF power of several watts or less at the output terminal of the DC pulse generator (121).

[0065] The above band stop filter (134) may include a series resonator (134b) including an inductor (Lb) and a capacitor (Cb) connected in parallel with each other. The reactance of the inductor (Lb) of the series resonator (134b) may be 200 ohms or less.

[0066] The above band stop filter (134) may include a shunt resonator (134a) including an inductor (La) and a capacitor (Ca) connected in series with each other. The shunt resonator (134a) is connected to ground, and the absolute value of the reactance of the capacitors (Ca, Cc) of the shunt resonators (134a, 134c) may be 200 ohms or less.

[0067] The band stop filter (134) may be designed to minimize distortion of the DC pulse waveform. Distortion of the DC pulse waveform (e.g., overshoot) may damage the substrate holder (130) and the power transmission device (130). As the order of the band stop filter (134) increases, overshoot increases and RF transmission power (e.g., scattering coefficient S21) decreases. In addition, serial connection (or increase in order) of the band stop filter (134) increases overshoot. Therefore, an appropriate order (or number of stages) is required. According to the present invention, the order of the band stop filter (134) may be preferably 3 to 5 stages. In the form of the band stop filter (134), the pi type may be advantageous in terms of overshoot compared to the T type.

[0068] An impedance converter (135) is connected to the output terminal of the band stop filter (134) to change the impedance of the band stop filter (134). The impedance converter (135) may be connected to a contact point between the first stage resonator (134a) and the second stage resonator (134b). The impedance converter (135) may change the impedance of the first stage resonator (134a) to have a high impedance. RF power incident on the impedance converter (135) may be reflected by the high impedance. The impedance converter (135) may be disposed inside the band stop filter (134). The impedance converter (135) is an inductor (L4), and the reactance of the inductor (L4) may be 25 ohms to 500 ohms.

[0069] The output terminal of the above impedance converter (135) and the output terminal of the DC blocking capacitor (133) are connected to each other and then connected to the electrode (124) through a transmission line (113). The transmission line (124) may be a high-voltage coaxial cable. The characteristic impedance of the transmission line (113) may be 50 ohms.

[0070] The load may include an electrode (124), a dielectric (125) disposed on the electrode (124), a substrate disposed on the dielectric (125), and plasma formed on the substrate. The load may include a negative reactive component. RF power incident on the contact point between the output terminal of the impedance converter (135) and the output terminal of the DC blocking capacitor (133) mainly proceeds in a direction with lower impedance. Therefore, the absolute value of the reactance of the impedance converter (135) may be greater than or equal to the absolute value of the reactance of the load. Accordingly, the RF power may mainly proceed in the direction of the load.

[0071] An RF sensor (136) may be placed between the band stop filter (134) and the DC pulse generator (121). The RF sensor (136) may include a current sensor and a voltage sensor.

[0072] The control unit (137) can receive the output signal of the RF sensor (136) and calculate the RF transmission power. If the RF transmission power is greater than a threshold value, the control unit (137) can provide an interrupt signal to the RF generator (111) or a warning signal to the user.

[0073] A voltage sensor (139) may be placed at the output terminal of the band stop filter (134). The voltage sensor (139) may measure the waveform of the DC pulse voltage and provide it to the control unit (137). The control unit (137) may analyze the waveform of the DC pulse voltage and display it to the user. The analysis of the waveform may include the amount of overshoot.

[0074] The RF generator (111) is a frequency variable RF generator, the band stop filter (134) is a pi-type band stop filter of three or more stages, and the band stop filter (134) may include a series resonator including an inductor (Lb) and a variable capacitor (Cb) connected in parallel. The variable capacitor (Cb) of the series resonator may be variable according to the driving frequency of the RF generator (111). The capacitance of the variable capacitor (Cb) may be variable so that the resonant frequency of the series resonator matches the driving frequency of the RF generator. The first stage resonator (134a) may include an inductor (La) and a capacitor (Ca) connected in series with each other. The second stage resonator (134b) may include an inductor (Lb) and a capacitor (Cb) connected in parallel with each other. The third stage resonator (134c) may include an inductor (Lc) and a capacitor (Cc) that are connected in series with each other. The electrostatic capacitance of the capacitor (Ca) of the first stage resonator (134a) and the capacitor (Cc) of the third stage resonator (134c) may be varied to match the driving frequency of the RF generator.

[0075] According to a modified embodiment of the present invention, even if the RF generator (111) is a frequency variable RF generator, the capacitor (Ca) of the first stage resonator (134a) can use a fixed value.

[0076] FIG. 5 is a drawing showing the connection relationship of a DC blocking capacitor according to another embodiment of the present invention.

[0077] Referring to FIG. 5, the DC blocking capacitor (133) may include a plurality of capacitors connected in series with each other. Accordingly, the applied voltage is evenly distributed to the capacitors, so that the insulation breakdown voltage of each capacitor can be reduced.

[0078] The above DC blocking capacitor (133) may include a plurality of capacitors connected in parallel with each other. Accordingly, the RF power can increase the current driving capability due to the low impedance of the DC blocking capacitor.

[0079] The DC blocking capacitor (133) may include a plurality of capacitors connected in series and parallel. Accordingly, the current driving capability and insulation breakdown voltage may be reduced. The maximum capacitance of the DC blocking capacitor (133) may be 50 pF.

[0080] FIG. 6 is a diagram showing impedance when viewed in the direction of a power transmission unit in the load direction according to one embodiment of the present invention.

[0081] Figure 7 shows the impedance change when an impedance converter is added to the power transmission unit.

[0082] Referring to FIGS. 6 and 7, the RF power reflected from the load sees the impedance of the impedance matching network (132) and the impedance of the band stop filter (134). If there is no impedance converter (135), the impedance of the band stop filter (134) approaches almost zero. Therefore, the reflected wave reflected from the load is transmitted through the band stop filter (134). Therefore, in order to increase the impedance of the band stop filter (134), an impedance converter (135) is required. The reactance of the impedance converter (135) may be 200 ohms or more. For example, at 60 MHz, the inductance of the impedance converter (135) may be 500 nH or more. When the impedance of the above impedance converter (135) is very large, in the Smith chart, the impedance of the band stop filter (134) changes from a short circuit to an open circuit.

[0083] Meanwhile, if the inductance of the impedance converter (135) increases, distortion (e.g., overshoot) of the DC pulse waveform may increase. Therefore, the absolute value of the reactance of the impedance converter (135) may be set to be greater than the absolute value of the reactance of the load.

[0084] FIG. 8 is a simulation result showing the operating range of an impedance matching network according to the reactance of an impedance converter according to one embodiment of the present invention.

[0085] Referring to Fig. 8, when the impedance converter (135) is an inductor (L4) and the reactance of the inductor (L4) is 25 ohms, 50 ohms, 100 ohms, 200 ohms, and 500 ohms, the operating range of the impedance matching network is respectively indicated on the Smith chart. Therefore, in order for the impedance matching network (132) to operate efficiently, the reactance of the impedance converter (135) may be 50 ohms to 500 ohms.

[0086] FIG. 9a and FIG. 9b show the transmission characteristics of a band stop filter according to the inductance of an impedance converter according to one embodiment of the present invention.

[0087] Referring to FIGS. 9A and 9B, S12 is a transmission coefficient or scattering coefficient between the RF generator (111) and the DC pulse generator (121). When the resonant frequency of the Vans-Stop filter (134) matches the driving frequency of 60 MHz, the RF power of the RF generator (111) decreases to -200 dB or less at 60 MHz.

[0088] Meanwhile, when the inductance of the impedance converter (135) is 1 nH, there is no change in transmittance at harmonics (120 MHz, 180 MHz). However, when the inductance of the impedance converter (135) is 500 nH, the transmittance changes at harmonics (120 MHz, 180 MHz). The impedance converter (135) operates as a type of low-pass filter and has the effect of suppressing high-frequency components. However, when the inductance of the impedance converter (135) increases, distortion (e.g., overshoot) of the DC pulse waveform may increase. Therefore, the absolute value of the reactance of the impedance converter (135) may be set to be greater than the absolute value of the reactance of the load.

[0089] FIGS. 10A and 10B illustrate the operating range of an impedance matching network when a band stop filter is removed from a power transmission device according to one embodiment of the present invention.

[0090] Referring to FIGS. 10A and 10B, when the Vans-Stop filter (134) is removed from the power transmission device (130), the power transmission device (130) operates as a general impedance matching network. If the load impedance exists within the indicated area, power generated from the power source can be transmitted to the load without loss.

[0091] FIGS. 11a to 11c illustrate the operating range of an impedance matching network when a band stop filter is included in a power transmission device according to one embodiment of the present invention.

[0092] Referring to FIGS. 11A and 11B, in the simulation, Ca, Cb, and Cc = 40, 50, and 60 pF, respectively. When the power transmission device (130) includes a band stop filter (134), if the inductance of the impedance converter (135) is 1 nH, the operating range of the impedance matching network (132) is very narrow. However, if the inductance of the impedance converter (135) is 500 nH, the operating range of the impedance matching network (132) is very wide. Therefore, a stable impedance matching operation can be performed depending on the load.

[0093] Referring to FIGS. 11A to 11C, in the simulation, Cb, Cc = 40, 50, 60 pF. Ca = 50 pF. When the power transmission device (130) includes a band stop filter (134), if the inductance of the impedance converter (135) is 1 nH, the operating range of the impedance matching network (132) is very narrow. However, if the inductance of the impedance converter (135) is 500 nH, the operating range of the impedance matching network (132) is very wide. Therefore, a stable impedance matching operation can be performed depending on the load.

[0094] FIGS. 12A to 12C are drawings showing the characteristics of a band stop filter according to one embodiment of the present invention.

[0095] Referring to FIGS. 12a to 12c, the band stop filter (134) includes first to fifth stage resonators (134a to 134e) and may be of a pi type. The transmittance (or scattering matrix S21) of the band stop filter having only the first stage resonator (134a) shows relatively high transmittance at the resonance frequency of 60 MHz. On the other hand, as the number of stages (or orders) of the band stop filter (134) increases to the second and third orders, it shows relatively low transmittance at the resonance frequency of 60 MHz. Therefore, the band stop filter (134) may be a pi type filter having three or more stages.

[0096] Meanwhile, the waveform of the DC pulse voltage shows that the first-stage band-stop filter exhibits the best overshoot characteristics. That is, as the order (or number of stages) of the band-stop filter (134) increases, the overshoot increases. Therefore, considering the overshoot, the band-stop filter (134) may be a pi-type filter with five stages or less.

[0097] FIGS. 13a to 13e are drawings showing the characteristics of a band stop filter according to one embodiment of the present invention.

[0098] Referring to FIGS. 13A to 13E, the band stop filter (134) may be a five-stage band stop filter. The band stop filter (134) includes a series inductor, a series capacitor, a shunt inductor, and a shunt capacitor.

[0099] Referring to Fig. 13b, when the series capacitor is varied to 100 pF, 200 pF, and 300 pF, the waveform of the DC pulse voltage hardly changes.

[0100] Referring to Fig. 13c, when the series inductor is varied to 100 nH, 200 nH, and 300 nH, the overshoot in the waveform of the DC pulse voltage increases as the inductance increases. Therefore, the inductance of the series inductor can be less than 200 nH.

[0101] Referring to Fig. 13d, when the shunt capacitor is varied to 100 pF, 200 pF, and 300 pF, the overshoot in the waveform of the DC pulse voltage is slightly reduced as the capacitance increases. Therefore, the capacitance of the shunt capacitor can be 100 pF or more.

[0102] Referring to Fig. 13e, when the shunt inductor is varied to 100 nH, 200 nH, and 300 nH, the overshoot in the waveform of the DC pulse voltage does not change with the increase in inductance.

[0103] Fig. 14 is a simulation result showing overshoot according to a series inductor in a band stop filter of a power transmission device according to one embodiment of the present invention.

[0104] Referring to Fig. 14, when the reactance of the series inductor is less than 200 ohms, the overshoot is maintained within 5%. In the simulation, a three-stage pi-type band-stop filter was used. The frequency of the DC pulse voltage was 400 kHz, the duty cycle was 50%, the rise and fall times were 250 nsec, and the maximum voltage was 10 kV. The actual load resistance was 50 to 200 ohms, and the load capacitance was 500 pF to 2500 pF.

[0105] To keep the overshoot below 5%, the reactance of the series inductor can be kept below 200 ohms.

[0106] Although the present invention has been illustrated and described with respect to specific preferred embodiments, the present invention is not limited to these embodiments, and includes various forms of embodiments that can be implemented by a person having ordinary skill in the art to which the invention pertains without departing from the technical spirit of the present invention claimed in the claims.

[0107] Description of the symbol

[0108] 111: RF generator

[0109] 121: Pulse generator

[0110] 130: Power transmission device

[0111] 132: Impedance matching network

[0112] 134: Band-stop filter

[0113] 133: DC blocking capacitor

[0114] 135: Impedance converter

Claims

1. An impedance matching network that delivers RF power from the RF generator to the load; A band stop filter that transmits the DC pulse voltage of the DC pulse generator to the load and suppresses the RF power from being transmitted to the DC pulse generator; A DC blocking capacitor connected to the output terminal of the impedance matching network to suppress the DC pulse voltage through the output terminal of the band stop filter from being transmitted to the impedance matching network; An impedance converter is included that is connected to the output terminal of the band stop filter and changes the impedance of the RF power incident on the band stop filter, A power transmission device characterized in that the output terminal of the above impedance converter and the output terminal of the above DC blocking capacitor are connected to each other and then connected to the load through a transmission line.

2. In paragraph 1, The above DC blocking capacitor is placed inside the above impedance matching network, A power transmission device characterized in that the above DC blocking capacitor is a high-voltage vacuum capacitor or a high-voltage ceramic capacitor.

3. In paragraph 1, A power transmission device characterized in that the above DC blocking capacitor is replaceable.

4. In paragraph 1, A power transmission device characterized in that the above DC blocking capacitors are multiple and connected in series to increase the withstand voltage.

5. In paragraph 1, The above impedance converter is placed inside the band stop filter, The above impedance transformer is an inductor, A power transmission device characterized in that the reactance of the above inductor is 25 ohms to 500 ohms.

6. In paragraph 1, A power transmission device characterized in that the load includes an electrode, a dielectric disposed on the electrode, a substrate disposed on the dielectric, and plasma formed on the substrate.

7. In paragraph 1, A power transmission device characterized in that the absolute value of the reactance of the impedance converter is greater than or equal to the absolute value of the reactance of the load.

8. In paragraph 1, A power transmission device characterized in that the above band stop filter is a pie-type band stop filter having three or more stages.

9. In paragraph 8, The above band stop filter comprises a series resonator including an inductor and a capacitor connected in parallel with each other, A power transmission device characterized in that the reactance of the inductor of the above series resonator is 200 ohms or less.

10. In paragraph 8, The above band stop filter comprises a shunt resonator comprising an inductor and a capacitor connected in series with each other, A power transmission device characterized in that the above shunt resonator is connected to ground.

11. In paragraph 1, The above RF generator is a frequency variable RF generator, The above band stop filter is a pie-type band stop filter of three or more stages, The above band stop filter comprises a series resonator including a parallel-connected inductor and a variable capacitor, The variable capacitor of the above series resonator is variable according to the driving frequency of the RF generator, A power transmission device characterized in that the capacitance of the variable capacitor is variable so that the resonant frequency of the series resonator matches the driving frequency of the RF generator.

12. In paragraph 1, an RF sensor disposed between the band stop filter and the DC pulse generator; and It further includes a control unit that receives the output signal of the RF sensor and calculates RF transmission power, A power transmission device characterized in that the control unit provides an interrupt signal to the RF generator when the RF transmission power is greater than a threshold value.

13. In paragraph 1, The above band stop filter is a pie-type band stop filter of three or more stages, The above band stop filter: A power transmission device comprising a first shunt resonator comprising a series-connected inductor and a fixed capacitor.

14. A substrate holder including an electrode supporting a substrate and a dielectric disposed on the electrode; A chamber arranged to surround the substrate holder; An RF generator that provides RF power to the electrode to generate plasma on the substrate; a DC pulse generator providing a DC pulse voltage to the electrode; and Includes a power transmission unit that transmits the RF power and the DC pulse voltage to the electrode, The above power transmission unit: An impedance matching network for transmitting the RF power of the RF generator to the electrode; A band stop filter for transmitting the DC pulse voltage of the DC pulse generator to the electrode and suppressing the RF power from being transmitted to the DC pulse generator; A DC blocking capacitor connected to the output terminal of the impedance matching network to suppress a DC pulse through the output terminal of the band stop filter from being transmitted to the impedance matching network; An impedance converter connected to the output terminal of the band stop filter and changing the impedance of the band stop filter is included, A plasma substrate processing device characterized in that the output terminal of the above impedance converter and the output terminal of the above DC blocking capacitor are connected to each other and then connected to the electrode through a transmission line.

15. In paragraph 14, The above DC blocking capacitor is placed inside the above impedance matching network, A plasma substrate processing device, characterized in that the above DC blocking capacitor is a high-voltage vacuum capacitor or a high-voltage ceramic capacitor.

16. In paragraph 14, A plasma substrate processing device characterized in that the above DC blocking capacitor is replaceable.

17. In paragraph 14, A power transmission device characterized in that the above DC blocking capacitors are multiple and connected in series to increase the withstand voltage.

18. In paragraph 14, The above impedance converter is placed inside the band stop filter, The above impedance transformer is an inductor, A plasma substrate processing device, characterized in that the reactance of the above inductor is 25 ohms to 500 ohms.

19. In paragraph 14, A plasma substrate processing device, characterized in that the absolute value of the reactance of the impedance converter is greater than or equal to the absolute value of the reactance of the load.

20. Impedance matching network that delivers RF power from the RF generator to the load; A band stop filter that transmits the DC pulse voltage of the DC pulse generator to the load and suppresses the RF power from being transmitted to the DC pulse generator; A DC blocking capacitor connected to the output terminal of the impedance matching network to suppress a DC pulse voltage through the output terminal of the band stop filter from being transmitted to the impedance matching network; A power transmission device characterized in that the output terminal of the band stop filter and the output terminal of the DC blocking capacitor are connected to each other and then connected to the load through a transmission line.

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