DC pulse power supply device

Abstract

To provide a DC pulse power supply device capable of making a load voltage of load that is a supply target of a DC pulse generated by a pulse conversion part a target voltage without changing a DC voltage supplied to the pulse conversion part.SOLUTION: A DC pulse power supply device 1 has a pulse conversion part 130, a variable resistor 140, and a variable resistor control part 150. The pulse conversion part 130 converts a DC voltage into a DC pulse, and outputs the DC pulse to a load (e.g. a capacitive load C). The variable resistor 140 is configured such that an electric resistance value may be variable, one end is connected to the pulse conversion part 130, and the other end is connected to the load. The variable resistor control part 150 is configured such that the electric resistance value of the variable resistor 140 may be controlled, and controls the electric resistance value of the variable resistor 140 so that load voltage that is load voltage at the time when the DC pulse generated by the pulse conversion part 130 is supplied may be a target voltage.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a DC pulse power supply device. [Background technology]

[0002] Conventionally, there have been DC pulse power supplies that generate pulse voltages whose amplitude changes in only one direction by performing ON / OFF control of a DC voltage at a predetermined timing. Such DC pulse power supplies are used, for example, in plasma processing equipment used for etching in the manufacture of semiconductor devices, and are used to correct and equalize the so-called "self-bias voltage" that occurs between a cathode electrode and a counter electrode that are arranged opposite each other in the chamber of the plasma processing equipment.

[0003] Patent Document 1 listed below discloses a DC pulse power supply device including a DC power supply, a DC / DC conversion unit that further converts a DC voltage generated by the DC power supply into a DC voltage of a different voltage value, and a pulse conversion unit that converts the DC voltage output from the DC / DC conversion unit into a DC pulse and outputs the DC pulse to a load (e.g., a capacitive load) of a plasma processing apparatus. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2022-049214 Summary of the Invention [Problem to be solved by the invention]

[0005] For example, the capacity of the chamber of a plasma processing apparatus, in other words, the capacity of the capacitor formed by the cathode electrode and the counter electrode, can change depending on the state of the plasma in the chamber. For example, the capacity of this capacitor changes depending on the high-frequency power supplied to the cathode electrode, the type of gas filled in the chamber, the gas pressure in the chamber, etc. In order to appropriately correct the above-mentioned self-bias voltage, it is desirable to control the voltage between the cathode electrode and the counter electrode to a desired value even if the capacity of the chamber changes.

[0006] One possible method for controlling the voltage between the cathode electrode and the counter electrode to a desired value is to vary the voltage value of the DC voltage supplied from the DC / DC converter to the pulse converter in accordance with the voltage between the cathode electrode and the counter electrode, as described in Patent Document 1. However, adopting such a method may complicate the operation of the DC / DC converter, increasing the burden on the DC / DC converter and increasing switching loss in the pulse converter.

[0007] The present invention provides a DC pulse power supply device that can set the load voltage of a load to which a DC pulse generated by a pulse conversion unit is supplied as a target voltage without varying the DC voltage supplied to the pulse conversion unit. [Means for solving the problem]

[0008] The present invention provides a pulse conversion unit that converts a DC voltage into a DC pulse and outputs the DC pulse to a load; a variable resistor configured to have a variable electrical resistance value, one end connected to the pulse conversion unit and the other end connected to the load; a variable resistance control unit configured to be able to control the electrical resistance value of the variable resistance; Equipped with the variable resistance control unit controls the electrical resistance value of the variable resistance so that a load voltage, which is a voltage of the load when the DC pulse is supplied, becomes a target voltage. It is a DC pulse power supply device. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a DC pulse power supply device that can set the load voltage of a load to which a DC pulse generated by a pulse conversion unit is supplied as a target voltage without varying the DC voltage supplied to the pulse conversion unit. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing an example of the configuration of a DC pulse power supply device 100 according to an embodiment of the present invention. [Figure 2] FIG. 2 is a diagram showing a first example of the configuration of the variable resistor 140. As shown in FIG. [Figure 3] FIG. 3 is a diagram showing a second example of the configuration of the variable resistor 140. In FIG. [Figure 4] FIG. 4 is a diagram showing a third example of the configuration of the variable resistor 140. In FIG. [Figure 5] FIG. 5 is a diagram showing an example of the effect of the DC pulse power supply device 100. [Figure 6] FIG. 6 is a diagram showing the configuration of a modified example of the DC pulse power supply device 100. In FIG. [Figure 7] FIG. 7 is a diagram showing an example of the effect of the modified DC pulse power supply device 100. DETAILED DESCRIPTION OF THE INVENTION

[0011] An embodiment of a DC pulse power supply device of the present invention will be described in detail below with reference to the drawings. The drawings should be viewed in the direction of the reference symbols. Note that not all of the features described in the following embodiment are necessarily essential to the present invention. Furthermore, two or more of the features described in the following embodiment may be arbitrarily combined. In the following, identical or similar elements will be assigned identical or similar reference symbols, and their description may be omitted or simplified.

[0012] <Configuration of DC pulse power supply> FIG. 1 is a diagram showing an example of the configuration of a DC pulse power supply 100 according to one embodiment of the present invention. The DC pulse power supply 1 shown in FIG. 1 is a device that generates DC pulses and supplies (i.e., applies) the generated DC pulses to a load (e.g., a capacitive load C). Here, the DC pulses are, for example, a pulse group including a plurality of power pulses, each having a predetermined pulse voltage, at a predetermined pulse period (i.e., a predetermined pulse interval). The capacitive load C is, for example, a capacitive load such as plasma generated between a cathode electrode and a counter electrode that are arranged opposite each other at a predetermined distance in a chamber of a plasma processing apparatus. In the following description, the load to which the DC pulses are supplied from the DC pulse power supply 1 will be referred to as the capacitive load C.

[0013] As shown in FIG. 1, the DC pulse power supply device 100 includes, for example, a DC power supply unit 110, a DC (Direct Current) / DC conversion unit 120, a pulse conversion unit 130, a variable resistor 140, and a variable resistor control unit 150.

[0014] The DC power supply unit 110 is a power supply circuit that generates a DC voltage to be used by the DC pulse power supply device 1 to generate a DC pulse, and outputs the generated DC voltage to the DC / DC conversion unit 120. More specifically, the DC power supply unit 110 has a positive terminal and a negative terminal, and outputs the generated DC voltage as a voltage between these terminals.

[0015] The DC / DC conversion unit 120 is a power conversion circuit that further converts the DC voltage received from the DC power supply unit 110 into a DC voltage of a different voltage value and outputs the converted DC voltage to the pulse conversion unit 130. More specifically, the DC / DC conversion unit 120 includes, for example, a first input terminal connected to a positive terminal of the DC power supply unit 110, a second input terminal connected to a negative terminal of the DC power supply unit 110, a first output terminal connected to a reference terminal (ground terminal) of the pulse conversion unit 130 described below, and a second output terminal connected to an input terminal of the pulse conversion unit 130.

[0016] The DC voltage output from the DC power supply unit 110 is input to the DC / DC conversion unit 120 via a first input terminal and a second input terminal. Then, the DC / DC conversion unit 120 converts the voltage value of the input DC voltage and outputs the converted DC voltage as a voltage between the first output terminal and the second output terminal. Note that the DC / DC conversion unit 120 operates, for example, under the control of a DC / DC control unit (not shown). This DC / DC control unit is realized, for example, by a microcomputer or the like configured by integrating a CPU (Central Processing Unit), memory, I / F (Interface), etc.

[0017] Furthermore, as shown in FIG. 1, in order to stabilize the power supplied from the DC / DC conversion unit 120 to the pulse conversion unit 130, a smoothing capacitor 160 or the like may be provided between the DC / DC conversion unit 120 and the pulse conversion unit 130.

[0018] The pulse converter 130 is a circuit that converts the DC voltage supplied from the DC / DC converter 120 into a DC pulse and outputs the generated DC pulse to the supply target, that is, the capacitive load C. More specifically, the pulse converter 130 includes a first switch 131 and a second switch 132, and converts the DC voltage into a DC pulse by alternately bringing the first switch 131 and the second switch 132 into a conductive state.

[0019] Each of the first switch 131 and the second switch 132 is configured by a switching element such as an NMOS (n-Channel Metal-Oxide-Semiconductor) transistor. Each of the first switch 11 and the second switch 12 may be configured by two or more switching elements.

[0020] In this embodiment, a first switch 131 and a second switch 132 are connected in series between the reference terminal (ground terminal) and input terminal of the pulse conversion unit 130. The pulse conversion unit 130 is a high-side grounded pulse conversion unit in which the drain terminal of the first switch 131 is electrically grounded. That is, in this embodiment, the first switch 131 is a high-side switch, and the second switch 132 is a low-side switch.

[0021] The pulse converter 130 operates under the control of, for example, a pulse controller (not shown). This pulse controller is realized by, for example, a microcomputer configured by integrating a CPU, memory, an I / F, etc. More specifically, the pulse controller is connected to the gate terminals of the first switch 131 and the second switch 132, and controls the gate voltages applied to these gate terminals to turn these switches on or off. For example, based on a synchronization signal received from a high-frequency power supply device (not shown) that supplies high-frequency power to the capacitive load C, the pulse controller controls the pulse converter 130 so that a DC pulse is supplied to the capacitive load C in synchronization with the supply of high-frequency power from the high-frequency power supply device.

[0022] Inductor 170 represents the inductance of the wiring from pulse converter 130 to capacitive load C, and does not necessarily include an inductor as a component. However, in order to suppress high-frequency current flowing from capacitive load C toward pulse converter 130, an inductor as a component may be provided separately.

[0023] The variable resistor 140 is configured to have a variable electrical resistance value, with one end connected to the pulse conversion unit 130 and the other end connected to the capacitive load C. The variable resistor 140 changes its electrical resistance value under control of a variable resistance control unit 150, which will be described later. For example, one end of the variable resistor 140 is connected between the source terminal of the NMOS transistor that constitutes the first switch 131 and the drain terminal of the NMOS transistor that constitutes the second switch 132. The other end of the variable resistor 140 is connected to the capacitive load C via an output terminal (not shown) that the DC pulse power supply 100 has. A specific configuration example of the variable resistor 140 will be described later, so a description thereof will be omitted here.

[0024] The variable resistance control unit 150 controls the electrical resistance value of the variable resistance 140 so that the load voltage, which is the voltage of the capacitive load C when a DC pulse is supplied (for example, the voltage between the cathode electrode and the counter electrode), becomes a target voltage. The variable resistance control unit 150 is realized by, for example, a microcomputer configured by integrating a CPU, memory, I / F, etc.

[0025] For example, if the load voltage has not reached the target voltage, the variable resistance control unit 150 increases the power supplied to the capacitive load C per unit time by decreasing the electrical resistance value of the variable resistor 140. This allows the load voltage to quickly approach the target voltage. Furthermore, if the load voltage is about to exceed the target voltage or has already exceeded it, the variable resistance control unit 150 increases the electrical resistance value of the variable resistor 140 to decrease the power supplied to the capacitive load C per unit time. This makes it possible to prevent the load voltage from exceeding the target voltage or to reduce the amount of overshoot that occurs when the load voltage exceeds the target voltage.

[0026] The target voltage can be, for example, the voltage value of the DC pulse generated by the pulse converter 130, in other words, the pulse voltage of the power pulse included in the DC pulse generated by the pulse converter 130. That is, the variable resistance controller 150 controls the electrical resistance value of the variable resistor 140 so that the load voltage becomes the target voltage equal to the voltage value of the DC pulse. This makes it possible to prevent the load voltage from failing to reach the voltage value of the DC pulse generated by the pulse converter 130, or from overshooting beyond the voltage value of the DC pulse.

[0027] More specifically, in this embodiment, a voltage sensor 200 and a peak hold circuit 210 are provided for controlling the variable resistor 140 by the variable resistor control unit 150. The voltage sensor 200 detects the load voltage in real time and outputs a detection signal indicating the detection result to the peak hold circuit 210.

[0028] The peak hold circuit 210 outputs a signal indicating the peak value (hereinafter also referred to as "peak value") of the load voltage detected within a predetermined period by the voltage sensor 200 to the variable resistance control unit 150. For example, the peak hold circuit 210 outputs a signal indicating the peak value detected within each pulse period of the DC pulse to the variable resistance control unit 150.

[0029] The variable resistance control unit 150 then controls the electrical resistance value of the variable resistance 140 based on the target voltage and the peak value received from the peak hold circuit 210. That is, the variable resistance control unit 150 decreases the electrical resistance value of the variable resistance 140 when the peak value has not reached the target voltage (for example, the voltage value of the DC pulse generated by the pulse conversion unit 130), and increases the electrical resistance value of the variable resistance 140 when the peak value is about to exceed the target voltage or has already exceeded the target voltage. This makes it possible to prevent the peak value from failing to reach the target voltage or overshooting beyond the target voltage.

[0030] The peak hold circuit 210 may include, for example, an A / D conversion unit. In this case, the A / D conversion unit generates, for example, a digital signal indicating a peak value and outputs the generated digital signal to the variable resistance control unit 150. As another example, the load voltage (analog value) detected by the voltage sensor 200 may be converted into a digital signal by the A / D conversion unit, and the peak hold circuit 210 may generate a digital signal indicating a peak value from the digital signal and output the digital signal to the variable resistance control unit 150.

[0031] 1 shows an example in which the voltage sensor 200 is provided outside the DC pulse power supply 100 and the peak hold circuit 210 is provided inside the DC pulse power supply 100, but their locations are not limited to this. For example, the peak hold circuit 210 may also be provided outside the DC pulse power supply 100.

[0032] <First example of variable resistor configuration> Fig. 2 is a diagram showing a first example of the configuration of the variable resistor 140. In this example, as shown in Fig. 2, the variable resistor 140 includes, for example, a plurality of resistors 141a, 141b, ..., 141n (hereinafter also referred to as "a plurality of resistors 141a to 141n") having different electrical resistance values, and a switch 142 that switches the conduction state of each of the plurality of resistors 141a to 141n.

[0033] In this example, each of the multiple resistors 141a to 141n is provided in parallel with the pulse conversion unit 130 and the capacitive load C. For example, one end of each of the multiple resistors 141a to 141n is connected to the pulse conversion unit 130 (for example, between the source terminal of the NMOS transistor that constitutes the first switch 131 and the drain terminal of the NMOS transistor that constitutes the second switch 132) via the switch 142. In addition, the other end of each of the multiple resistors 141a to 141n is connected to the capacitive load C.

[0034] The switch 142 turns on one or more resistors included in the plurality of resistors 141a to 141n in accordance with the control of the variable resistance control unit 150. When one resistor is turned on, the electrical resistance value of that resistor becomes the electrical resistance value of the variable resistance 140. When two or more resistors are turned on, the combined resistance of these resistors becomes the electrical resistance value of the variable resistance 140.

[0035] In this example, for example, information indicating which of the plurality of resistors 141a to 141n should be brought into a conductive state in accordance with the difference between the target voltage and the load voltage (for example, peak value) is stored in advance in the variable resistance control unit 150. Then, the variable resistance control unit 150 controls the switch 142 while referring to this information, thereby controlling the electrical resistance value of the variable resistance 140.

[0036] Each of the plurality of resistors 141a to 141n may be configured with a single resistor, or may be configured by connecting two or more resistors in series or parallel. Furthermore, the positions of the plurality of resistors 141a to 141n and the switch 142 may be reversed. That is, the plurality of resistors 141a to 141n may be arranged on the pulse conversion unit 130 side, and the switch 142 may be arranged on the capacitive load C side. Furthermore, in the example shown in FIG. 2, the variable resistor 140 includes three or more resistors 141a to 141n, but this is not limiting. For example, the variable resistor 140 may include only two resistors, resistor 141a and resistor 141b.

[0037] As described above, according to this example, the variable resistor 140 is configured to include a plurality of resistors 141a to 141n that have different electrical resistance values ​​and are provided in parallel with the pulse conversion unit 130 and the capacitive load C, and a switch 142 that switches the conduction state of the plurality of resistors 141a to 141n under control of the variable resistor control unit 150. This allows the variable resistor 140 to be configured mainly from passive elements, namely the plurality of resistors 141a to 141n, and therefore makes it possible to obtain a variable resistor 140 that is inexpensive and has excellent durability compared to a variable resistor 140 configured mainly from active elements such as transistors.

[0038] Furthermore, in this example, since the electrical resistance value of the variable resistor 140 may be discrete, if more precise control of the load voltage is desired, the voltage value of the DC voltage supplied to the pulse converter 130 (i.e., the DC voltage generated by the DC / DC converter 120) may also be adjusted accordingly. Even in this case, the burden on the DC / DC converter 120 can be reduced compared to when the load voltage is set to the target voltage by varying only the DC voltage supplied to the pulse converter 130.

[0039] <Second example of variable resistor configuration> 3 is a diagram showing a second example of the configuration of the variable resistor 140. In this example, as shown in FIG. 3, the variable resistor 140 includes, for example, a first FET 143, a second FET 144, and a gate voltage control unit 145.

[0040] The first FET 143 and the second FET 144 are each configured, for example, by an NMOS transistor, and are provided with their source terminals connected to each other. The drain terminal of the first FET 143 is connected to the pulse conversion unit 130 (for example, between the source terminal of the NMOS transistor that configures the first switch 131 and the drain terminal of the NMOS transistor that configures the second switch 132). The drain terminal of the second FET 144 is connected to a capacitive load C.

[0041] The gate voltage control unit 145 is connected to the gate terminals of the first FET 143 and the second FET 144, and controls the gate voltages applied to the gate terminals of the first FET 143 and the second FET 144 in accordance with instructions from the variable resistance control unit 150.

[0042] For example, when the first switch 131 of the pulse converter 130 is in a conductive state (in other words, when a current flows from the pulse converter 130 side to the capacitive load C side), the gate voltage controller 145 controls the gate voltage of the first FET 143 in accordance with an instruction from the variable resistance controller 150. At this time, the gate voltage controller 145 controls the gate voltage of the first FET 143 so that the voltage between the gate terminal and source terminal of the first FET 143 becomes the value instructed by the variable resistance controller 150. This makes it possible to set the electrical resistance value between the drain terminal and source terminal of the first FET 143 to a desired value. In this case, the electrical resistance value between the drain terminal and source terminal of the first FET 143 becomes the electrical resistance value of the variable resistor 140.

[0043] Furthermore, when the second switch 132 of the pulse converter 130 is in a conductive state (in other words, when a current flows from the capacitive load C side to the pulse converter 130 side), the variable resistance controller 150 controls the gate voltage of the second FET 144 in accordance with an instruction from the variable resistance controller 150. At this time, the gate voltage controller 145 controls the gate voltage of the second FET 144 so that the voltage between the gate terminal and source terminal of the second FET 144 becomes the value instructed by the variable resistance controller 150. This makes it possible to set the electrical resistance value between the drain terminal and source terminal of the second FET 144 to a desired value. In this case, the electrical resistance value between the drain terminal and source terminal of the second FET 144 becomes the electrical resistance value of the variable resistor 140.

[0044] The gate voltage control unit 145 is realized by, for example, a microcomputer configured by integrating a CPU, a memory, an I / F, etc. In the present example, information indicating the value of the voltage between the gate terminal and the source terminal of the first FET 143 and the second FET 144 according to the difference between the target voltage and the load voltage (for example, the peak value) is stored in advance in the variable resistance control unit 150. The variable resistance control unit 150 then controls the electrical resistance value of the variable resistance 140 by issuing instructions to the gate voltage control unit 145 while referring to this information.

[0045] As described above, according to this example, the variable resistor 140 includes the first FET 143 and the second FET 144, each of which is an NMOS transistor and whose source terminals are connected to each other, and the gate voltage control unit 145, which controls the gate voltages of the first FET 143 and the second FET 144 according to instructions from the variable resistor control unit 150. The drain terminal of the first FET 143 is connected to the pulse conversion unit 130, and the drain terminal of the second FET 144 is connected to the capacitive load C. By configuring the variable resistor 140 in this way, the electrical resistance value of the variable resistor 140 can be controlled more precisely than when the variable resistor 140 is configured using a plurality of resistors 141a to 141n as shown in FIG. 2.

[0046] <Third example of variable resistor configuration> Fig. 4 is a diagram showing a third example of the configuration of the variable resistor 140. In this example, as shown in Fig. 4, the variable resistor 140 includes, for example, a first diode 146a, a second diode 146b, a third diode 147a, a fourth diode 147b, an FET 148, and a gate voltage control unit 149.

[0047] The first diode 146a and the second diode 146b are connected in series, and the anode terminal of the first diode 146a and the cathode terminal of the second diode 146b are connected to each other. A connection point P1 between the anode terminal of the first diode 146a and the cathode terminal of the second diode 146b is connected to the pulse conversion unit 130 (for example, between the source terminal of the NMOS transistor that constitutes the first switch 131 and the drain terminal of the NMOS transistor that constitutes the second switch 132).

[0048] Similarly, the third diode 147a and the fourth diode 147b are connected in series, and the anode terminal of the third diode 147a and the cathode terminal of the fourth diode 147b are connected to each other. A connection point P2 between the anode terminal of the third diode 147a and the cathode terminal of the fourth diode 147b is connected to a capacitive load C.

[0049] The cathode terminals of the first diode 146a and the third diode 147a are connected to each other, and the anode terminals of the second diode 146b and the fourth diode 147b are connected to each other.

[0050] The FET 148 is configured by, for example, an NMOS transistor. The drain terminal of the FET 148 is connected to the cathode terminals of the first diode 146a and the third diode 147a (in other words, the connection point between the cathode terminal of the first diode 146a and the cathode terminal of the third diode 147a). The source terminal of the FET 148 is connected to the anode terminals of the second diode 146b and the fourth diode 147b (in other words, the connection point between the anode terminal of the second diode 146b and the anode terminal of the fourth diode 147b).

[0051] The gate voltage control unit 149 is connected to the gate terminal of the FET 148 , and controls the gate voltage applied to the gate terminal of the FET 148 in accordance with instructions from the variable resistance control unit 150 .

[0052] In this example, when the first switch 131 of the pulse converter 130 is in a conductive state (in other words, when a current flows from the pulse converter 130 side to the capacitive load C side), a current flows through the variable resistor 140 as shown by the arrow α in Fig. 4. That is, in this case, a current flows from the first diode 146a through the FET 148 and out of the fourth diode 147b.

[0053] Furthermore, when the second switch 132 of the pulse converter 130 is in a conductive state (in other words, when a current flows from the capacitive load C side to the pulse converter 130 side), a current flows through the variable resistor 140 as shown by the arrow β in Fig. 4. That is, in this case, a current flows from the third diode 147a through the FET 148 and out of the second diode 146b.

[0054] In this example, whether the first switch 131 of the pulse conversion unit 130 is in a conductive state or the second switch 132 is in a conductive state, the gate voltage control unit 149 controls the gate voltage of the FET 148 so that the voltage between the gate terminal and the source terminal of the FET 148 becomes a value instructed by the variable resistance control unit 150. This makes it possible to set the electrical resistance value between the drain terminal and the source terminal of the FET 148 to a desired value. That is, in this example, whether the first switch 131 is in a conductive state or the second switch 132 is in a conductive state, the electrical resistance value between the drain terminal and the source terminal of the FET 148 becomes the electrical resistance value of the variable resistor 140.

[0055] The gate voltage control unit 149 is realized by, for example, a microcomputer configured by integrating a CPU, a memory, an I / F, etc. In the present example, information indicating the value of the voltage between the gate terminal and the source terminal of the FET 148 according to the difference between the target voltage and the load voltage (for example, the peak value) is stored in advance in the variable resistance control unit 150. The variable resistance control unit 150 then controls the electrical resistance value of the variable resistance 140 by issuing instructions to the gate voltage control unit 149 while referring to this information.

[0056] As described above, the variable resistor 140 of this example is configured to include a first diode 146 a and a second diode 146 b arranged in series, a third diode 147 a and a fourth diode 147 b arranged in series, an NMOS transistor FET 148, and a gate voltage control unit 149 that controls the gate voltage of the FET 148 in accordance with instructions from the variable resistor control unit 150.

[0057] In the variable resistor 140 of this example, the anode terminal of the first diode 146a and the cathode terminal of the second diode 146b are connected to each other, and a connection point P1 between the anode terminal of the first diode 146a and the cathode terminal of the second diode 146b is connected to the pulse conversion unit 130. The anode terminal of the third diode 147a and the cathode terminal of the fourth diode 147b are connected to each other, and a connection point P2 between the anode terminal of the third diode 147a and the cathode terminal of the fourth diode 147b is connected to the capacitive load C. Furthermore, the cathode terminals of the first diode 146a and the third diode 147a are connected to each other, and the anode terminals of the second diode 146b and the fourth diode 147b are connected to each other. The drain terminal of the FET 148 is connected to the cathode terminals of the first diode 146a and the third diode 147a, and the source terminal of the FET 148 is connected to the anode terminals of the second diode 146b and the fourth diode 147b.

[0058] With the variable resistor 140 configured in this manner, the number of NMOS transistors required to configure the variable resistor 140 can be reduced compared to when the variable resistor 140 is configured using multiple NMOS transistors as shown in FIG. 3, while still allowing for fine control of the electrical resistance value of the variable resistor 140.

[0059] <Effects of this embodiment> FIG. 5 is a diagram showing an example of the effect of the DC pulse power supply device 100. In FIG. 5(a), the solid line represents the on (i.e., conductive state) and off (i.e., non-conductive state) of the first switch 131 at each time, and the dashed-dotted line represents the on / off state of the second switch 132 at each time. In FIG. 5(b), the target voltage and load voltage at each time are shown in a conventional configuration. Here, the conventional configuration is, for example, a configuration in which a damping resistor with a constant electrical resistance is provided instead of the variable resistor 140 shown in FIG. 1, and in which control such as varying the voltage value of the DC voltage supplied from the DC / DC converter 120 to the pulse converter 130 in accordance with the load voltage is not performed. In FIG. 5(c), the target voltage and load voltage at each time are shown in a configuration according to this embodiment.

[0060] As shown in (b) of Fig. 5, in the configuration of the conventional example, a state occurs in which the crest value, which is the peak value of the load voltage in each pulse period, does not reach the target voltage (here, the voltage value of the DC pulse generated by the pulse conversion unit 130), or an overshoot occurs that exceeds the target voltage. In contrast, as shown in (c) of Fig. 5, with the configuration of this embodiment, it is possible to prevent the crest value from not reaching the target voltage or an overshoot that exceeds the target voltage.

[0061] As described above, according to this embodiment, the load voltage of the capacitive load C, to which the DC pulse generated by the pulse converter 130 is supplied, can be set to a target voltage without varying the DC voltage supplied to the pulse converter 130. Therefore, compared to when the voltage value of the DC voltage supplied from the DC / DC converter 120 to the pulse converter 130 is varied depending on the load voltage, the load voltage can be set to the target voltage while suppressing an increase in the load on the DC / DC converter 120 and an increase in the switching loss of the pulse converter 130. Furthermore, by setting the load voltage to the target voltage, it becomes possible to appropriately correct the self-bias voltage generated between, for example, a cathode electrode and a counter electrode arranged opposite each other in a chamber of a plasma processing apparatus so that the self-bias voltage can be uniform.

[0062] <Modification of this embodiment> Next, a modified example of this embodiment will be described. Fig. 6 is a diagram showing the configuration of a modified example of the DC pulse power supply device 100. In the following, parts that are common to Fig. 1 are given the same reference numerals, and their description will be omitted.

[0063] 6, the DC pulse power supply apparatus 100 of this modified example further includes a diode 190. The diode 190 has a cathode terminal grounded and an anode terminal connected between the variable resistor 140 and the capacitive load C (for example, between the inductor 170 and the capacitive load C). By providing such a diode 190, the power line from the variable resistor 140 to the capacitive load C can be grounded via the diode 190. This makes it possible to prevent ringing of a potential equal to or higher than the ground potential, which is caused by the switching operation of the pulse converter 130, from occurring on the power line from the variable resistor 140 to the capacitive load C.

[0064] <Effects of the modified version> Fig. 7 is a diagram showing an example of the effect of the modified DC pulse power supply 100. In Fig. 7(a), the solid line represents the on / off state of the first switch 131 at each time, and the dashed line represents the on / off state of the second switch 132 at each time. In Fig. 7(b), the target voltage and load voltage at each time are shown when the diode 190 is not provided (i.e., when the configuration shown in Fig. 1 is used). In Fig. 7(c), the target voltage and load voltage at each time are shown when the configuration of this modified example is used.

[0065] 7(b), in a configuration without diode 190, an overshoot in which the peak value exceeds the target voltage (here, the voltage value of the DC pulse generated by pulse converter 130) may occur due to the influence of ringing at or above the ground potential caused by the switching operation of pulse converter 130. In contrast, as shown in FIG. 7(c), the configuration of this modified example makes it possible to prevent the occurrence of an overshoot in which the peak value exceeds the target voltage.

[0066] Although various embodiments have been described above with reference to the drawings, it goes without saying that the present invention is not limited to such examples. It is clear that a person skilled in the art can conceive of various modifications or alterations within the scope of the claims, and it is understood that these also naturally fall within the technical scope of the present invention. Furthermore, the components of the above-described embodiments may be combined in any manner without departing from the spirit of the invention.

[0067] This specification etc. describes at least the following matters. Note that the components etc. corresponding to those in the above-mentioned embodiment are shown in parentheses, but are not limited to these.

[0068] (1) a pulse conversion unit (pulse conversion unit 130) that converts a DC voltage into a DC pulse and outputs the DC pulse to a load (capacitive load C); a variable resistor (variable resistor 140) configured to have a variable electrical resistance value, one end connected to the pulse conversion unit and the other end connected to the load; a variable resistance control unit (variable resistance control unit 150) configured to be able to control the electrical resistance value of the variable resistance; Equipped with the variable resistance control unit controls the electrical resistance value of the variable resistance so that a load voltage, which is a voltage of the load when the DC pulse is supplied, becomes a target voltage. DC pulse power supply.

[0069] According to (1), the load voltage of the load to which the DC pulses generated by the pulse converter are supplied can be set to the target voltage without varying the DC voltage supplied to the pulse converter. Therefore, compared to when the voltage value of the DC voltage supplied to the pulse converter is varied depending on the load voltage, for example, the load voltage can be set to the target voltage while suppressing an increase in the load on the DC / DC converter that supplies the DC voltage to the pulse converter and an increase in the switching loss of the pulse converter.

[0070] (2) The DC pulse power supply device according to (1), the variable resistance control unit controls the electrical resistance value of the variable resistance so that the load voltage becomes the target voltage which is equal to the voltage value of the DC pulse. DC pulse power supply.

[0071] According to (2), it is possible to prevent the load voltage from failing to reach the voltage value of the DC pulse generated by the pulse conversion unit, or to prevent an overshoot from occurring in which the load voltage exceeds the voltage value of the DC pulse.

[0072] (3) The DC pulse power supply device according to (1) or (2), The variable resistor is a plurality of resistors (resistors 141a to 141n) having different electrical resistance values ​​and arranged in parallel with the pulse converter and the load; a switch (switch 142) that switches the conduction state of the plurality of resistors according to the control by the variable resistance control unit, DC pulse power supply.

[0073] According to (3), since the variable resistor can be constructed mainly from passive elements such as multiple resistors, it is possible to obtain a variable resistor that is inexpensive and has excellent durability compared to a variable resistor constructed mainly from active elements such as transistors.

[0074] (4) The DC pulse power supply device according to (1) or (2), The variable resistor is a first FET (first FET 143) and a second FET (second FET 144), each of which is an NMOS transistor and whose source terminals are connected to each other; a gate voltage control unit (gate voltage control unit 145) that controls the gate voltages of the first FET and the second FET according to instructions from the variable resistance control unit; Equipped with a drain terminal of the first FET connected to the pulse converter; The drain terminal of the second FET is connected to the load. DC pulse power supply.

[0075] According to (4), the electrical resistance value of the variable resistor can be controlled more precisely than when the variable resistor is made up of a plurality of resistors each having a predetermined electrical resistance value.

[0076] (5) The DC pulse power supply device according to (1) or (2), The variable resistor is a first diode (first diode 146a) and a second diode (second diode 146b) arranged in series; a third diode (third diode 147a) and a fourth diode (fourth diode 147b) arranged in series; an FET (FET148) which is an NMOS transistor; a gate voltage control unit (gate voltage control unit 149) that controls the gate voltage of the FET according to an instruction from the variable resistance control unit; The invention comprises: an anode terminal of the first diode and a cathode terminal of the second diode are connected to each other, and a connection point (connection point P1) between the anode terminal of the first diode and the cathode terminal of the second diode is connected to the pulse conversion unit; the anode terminal of the third diode and the cathode terminal of the fourth diode are connected to each other, and a connection point (connection point P2) between the anode terminal of the third diode and the cathode terminal of the fourth diode is connected to the load; The cathode terminals of the first diode and the third diode are connected to each other, The second diode and the fourth diode have their anode terminals connected to each other, a drain terminal of the FET connected to the cathode terminals of the first diode and the third diode; a source terminal of the FET connected to the anode terminals of the second diode and the fourth diode; DC pulse power supply.

[0077] According to (5), the number of NMOS transistors required to configure a variable resistor can be reduced compared to when multiple NMOS transistors are used to configure a variable resistor, while still allowing for precise control of the electrical resistance value of the variable resistor.

[0078] (6) A DC pulse power supply device according to any one of (1) to (5), Further provided is a diode (diode 190) having a cathode terminal grounded and an anode terminal connected between the variable resistor and the load. DC pulse power supply.

[0079] According to (6), it is possible to suppress the occurrence of an overshoot in which the load voltage exceeds the target voltage due to the influence of ringing above the ground potential caused by the switching operation of the pulse conversion unit. [Explanation of symbols]

[0080] 100 DC pulse power supply 130 Pulse conversion unit 131 First Switch 132 Second Switch 140 Variable Resistor 141a~141n Resistance 142 Switch 145,149 Gate voltage control section 146a First diode 146b Second diode 147a Third diode 147b Fourth diode 148FET 150 Variable resistance control section 190 Diode P1, P2 connection points

Claims

1. a pulse conversion unit that converts a DC voltage into a DC pulse and outputs the DC pulse to a load; a variable resistor configured to have a variable electrical resistance value, one end connected to the pulse conversion unit and the other end connected to the load; a variable resistance control unit configured to be able to control the electrical resistance value of the variable resistance; Equipped with the variable resistance control unit controls the electrical resistance value of the variable resistance so that a load voltage, which is a voltage of the load when the DC pulse is supplied, becomes a target voltage. DC pulse power supply.

2. 2. The DC pulse power supply device according to claim 1, the variable resistance control unit controls the electrical resistance value of the variable resistance so that the load voltage becomes the target voltage which is equal to the voltage value of the DC pulse. DC pulse power supply.

3. 2. The DC pulse power supply device according to claim 1, The variable resistor is a plurality of resistors having different electrical resistance values ​​and arranged in parallel with the pulse converter and the load; a switch that switches the conduction state of the plurality of resistors according to control by the variable resistance control unit, DC pulse power supply.

4. 2. The DC pulse power supply device according to claim 1, The variable resistor is a first FET and a second FET, each of which is an NMOS transistor, and whose source terminals are connected to each other; a gate voltage control unit that controls the gate voltages of the first FET and the second FET according to an instruction from the variable resistance control unit; Equipped with a drain terminal of the first FET connected to the pulse converter; The drain terminal of the second FET is connected to the load. DC pulse power supply.

5. 2. The DC pulse power supply device according to claim 1, The variable resistor is a first diode and a second diode arranged in series; a third diode and a fourth diode arranged in series; an FET which is an NMOS transistor; a gate voltage control unit that controls a gate voltage of the FET in accordance with an instruction from the variable resistance control unit; The invention comprises: an anode terminal of the first diode and a cathode terminal of the second diode are connected to each other, and a connection point between the anode terminal of the first diode and the cathode terminal of the second diode is connected to the pulse conversion unit; an anode terminal of the third diode and a cathode terminal of the fourth diode are connected to each other, and a connection point between the anode terminal of the third diode and the cathode terminal of the fourth diode is connected to the load; The cathode terminals of the first diode and the third diode are connected to each other, The second diode and the fourth diode have their anode terminals connected to each other, a drain terminal of the FET connected to the cathode terminals of the first diode and the third diode; a source terminal of the FET connected to the anode terminals of the second diode and the fourth diode; DC pulse power supply.

6. 6. The DC pulse power supply device according to claim 1, a diode having a cathode terminal grounded and an anode terminal connected between the variable resistor and the load; DC pulse power supply.

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