JP4841949B2 - Vacuum device and power supply method for vacuum device - Google Patents

Description

  The present invention relates to a vacuum apparatus provided with an abnormal discharge prevention device having a function of extinguishing an abnormal discharge when an abnormal discharge such as an arc discharge occurs, or a function of preventing the occurrence of an abnormal discharge in advance, and a power supply method therefor About.

  Conventionally, a DC circuit provided with an inverter circuit including one or more switching semiconductor elements, a rectifier that converts the AC output into a DC output, and a smoothing circuit that includes a smoothing inductor and a smoothing capacitor that smooth the DC output. In a vacuum device using a vacuum such as a sputtering device connected to a power source, an etching device, an electron beam evaporation device, or a PVD (Physical Vapor Deposition) device, the impedance of the electrode of the vacuum load in the vacuum device is reduced. Or, conductive dust or the like short-circuits the electrodes, causing abnormal discharge temporarily in the plasma state, or in the electron beam evaporation system, between the high potential filament and the surrounding electrodes May cause abnormal discharge.

  In the sputtering apparatus, when abnormal discharge occurs, defects in the substrate material such as liquid crystal during sputtering, or defects in the metal film in a compact disc or DVD (Digital Versatile Disk) are said to reduce the product yield. There was a problem. In addition, in the electron beam evaporation apparatus, the filament breaks due to the discharge energy. Therefore, it is necessary to prevent the occurrence of abnormal discharge as much as possible (see Patent Document 1). Conventionally, as a measure against abnormal discharge in these vacuum devices, the abnormal discharge occurrence detection mechanism in the abnormal discharge prevention device detects the occurrence of abnormal discharge, outputs an abnormal discharge detection signal, turns on the semiconductor switch, and reverse voltage power supply The abnormal discharge is extinguished in a short time by applying a reverse voltage to the vacuum load or by turning on a semiconductor switch to short-circuit both ends of the vacuum load. As another measure against abnormal discharge, the abnormal discharge prediction detection mechanism in the abnormal discharge prevention device detects the occurrence of abnormal discharge and outputs an abnormal discharge prediction signal. As described above, reverse voltage is applied to the vacuum load. Or by short-circuiting both ends of the vacuum load, the occurrence of abnormal discharge is prevented. Furthermore, as another countermeasure against abnormal discharge, an abnormal discharge prevention signal is periodically output, and a reverse voltage is periodically applied to the vacuum load as described above, or both ends of the vacuum load are short-circuited. The occurrence of discharge is prevented in advance (see, for example, Patent Document 2).

Another measure against abnormal discharge is to prevent an abnormal discharge by avoiding an increase in the current flowing through the current stabilization inductance element to stabilize the current flowing through the vacuum load when an abnormal discharge occurs in the vacuum load. In order to suppress an increase in the current flowing through the device, the inverter device control function is stopped for a predetermined time, and all switching semiconductor elements constituting the inverter device are turned off to stop the inverter device. When the inverter device is stopped as described above, there is a problem in that the transformer is biased at the time of return and overcurrent flows, and the inverter device becomes unstable. Furthermore, many inverter devices have a soft start function to prevent inrush current, but in this case, it is stated that there is a problem that it takes time to restore the inverter device and adversely affects the vacuum load. (See Patent Document 3). In general, such a DC power supply device includes a smoothing inductor for stabilizing the output. In addition to the smoothing inductor of the DC power supply device, the abnormal discharge prevention device is provided with a current stabilizing inductance element having a large inductance of several hundred μH to several mH. The reason is that the larger the inductance, the more stable the electron beam or plasma discharge is due to the current sustaining action of the inductance, and the more difficult it is to shift to abnormal discharge.
JP-A-8-311647 JP 2005-318714 A JP 2001-295042 A

  However, in the countermeasure against abnormal discharge as described in Patent Document 1, the abnormal discharge can be eliminated relatively quickly, but the current that flows when the abnormal discharge prevention device operates is abnormal discharge. The peak value of the current that flows through the current stabilizing inductance element immediately before the prevention device operates, the current due to the energy supplied from the DC power supply, or the voltage obtained by adding the reverse voltage to the output voltage of the DC power supply A large current flows through the semiconductor switch in the current stabilizing inductor element and the abnormal discharge prevention device. In such an abnormal discharge countermeasure, it is effective to increase the reverse voltage and lengthen the reverse voltage application time from the viewpoint of quickly eliminating the abnormal discharge. As described above, there is a problem that the current flowing through the semiconductor switch in the current stabilizing inductor element and the abnormal discharge prevention device increases. Therefore, in the actual vacuum apparatus, the magnitude of the reverse voltage, the application time thereof, the inductance of the current stabilizing inductor element, and the like are determined in consideration of the balance of the above conditions. In addition, when the semiconductor switch is turned off in a state where the current flowing through the semiconductor switch in the current stabilizing inductor element and the abnormal discharge prevention device is large, the current flowing through the current stabilizing inductance element is reduced to a vacuum load. Therefore, there is a problem that abnormal discharge may be caused again, and therefore a capacitor snubber circuit having a large capacity must be provided in parallel with the vacuum load.

  In the case of the method described in the above-mentioned Patent Document 2, problems caused by the method of the above-mentioned Patent Document 1 can be reduced. However, as described above, since the inverter circuit of the DC power supply device is stopped when the abnormal discharge prevention function works, it takes time until the DC power supply device returns to the state of outputting the rated output voltage when the inverter circuit is restored. And there is a problem that the transformer may be biased when the inverter circuit is restored, and it is difficult to use such a technique as a power supply device that supplies power to the vacuum load. Furthermore, since the conventional DC power supply device has a smoothing inductor on the output side, the energy stored in the smoothing inductor is released even when the inverter circuit stops operating. There is also the disadvantage that energy continues to be supplied.

  Accordingly, the present invention solves the above-mentioned problems, and when the abnormal discharge prevention function works, when the abnormal discharge prevention function works by minimizing the current flowing from the DC power supply device to the abnormal discharge prevention device. The main purpose is to reduce the peak value of the current flowing through the stabilizing inductor as compared with the conventional case, while hardly increasing the current that has been flowing through the stabilizing inductance.

A first invention includes a vacuum load, a DC power supply device that supplies power to the vacuum load, and an abnormal discharge prevention device that is provided between the DC power supply device and the vacuum load to prevent occurrence of abnormal discharge. in the vacuum device, the DC power supply device is connected to a transformer, the primary winding of the transformer, an inverter with a switching semiconductor element for controlling the power fed to the vacuum load, the secondary winding of the transformer comprising a connected Ru rectifier circuit, a control circuit providing a control signal for controlling the switching semiconductor element and a gate circuit that is provided between the control circuit and the control terminal of the switching semiconductor element, said The abnormal discharge prevention device outputs an abnormal discharge detection signal when the occurrence of abnormal discharge in the vacuum load is detected, or abnormal discharge is detected when a sign of occurrence of abnormal discharge is detected. A predictive signal is output, or an abnormal discharge prevention signal periodically generated to prevent the occurrence of abnormal discharge in the vacuum load is output, and the abnormal discharge prevention device detects the abnormal discharge detection signal or the gate circuit. When outputting the abnormal discharge prediction signal or the abnormal discharge prevention signal, the control circuit and the control terminal of the switching semiconductor element are blocked for a preset passage prohibition period, during the passage prohibition period Provides a vacuum apparatus, wherein the control signal is not passed through the control terminal of the switching semiconductor element, and the control signal is passed through the control terminal of the switching semiconductor element when the passage prohibition period has elapsed. .

The second invention is the first invention, the passage prohibition period is at 100μs or less from 10 [mu] s, the response time of the control circuit to provide a vacuum apparatus characterized by longer than the passing prohibition period.

  According to a third invention, in the first invention or the second invention, the passage prohibition period is formed when the abnormal discharge detection signal, the abnormal discharge prediction signal, or the abnormal discharge prevention signal is generated. A vacuum apparatus characterized by having a period substantially equal to a pulse width of a signal.

  According to a fourth invention, in any one of the first to third inventions, the power reference source having a reference power value compared with a load power detection signal proportional to the load power of the vacuum load, An error amplifier that outputs an error amplification signal equal to a difference between a load power detection signal and the reference power value to the control circuit, and the power reference source is configured to output the reference power value in a steady state during the passage prohibition period. The present invention provides a vacuum apparatus characterized by providing a lower reference power value.

  A fifth invention is a capacitor input type according to any one of the first to fourth inventions, wherein the rectifier circuit includes a smoothing capacitor between output terminals and substantially does not include a smoothing inductor. There is provided a vacuum apparatus characterized in that:

  According to a sixth invention, in any one of the first to fifth inventions, the abnormal discharge prevention device detects an occurrence of abnormal discharge in the vacuum load or detects a sign of occurrence of abnormal discharge. Or when outputting an abnormal discharge prevention signal periodically generated to prevent the occurrence of abnormal discharge in the vacuum load, a voltage of reverse polarity is applied to the vacuum load, or both ends of the vacuum load are connected. Provided is a vacuum apparatus comprising a semiconductor switch for short-circuiting.

  A seventh invention includes a DC power supply device including a vacuum load, an inverter including a switching semiconductor element that controls power supplied to the vacuum load, and a control circuit that controls the inverter, the DC power supply device, and the vacuum In a power supply method for a vacuum apparatus comprising an abnormal discharge prevention device provided between a load and the load, the abnormal discharge prevention device indicates an abnormal discharge detection signal indicating the occurrence of abnormal discharge or a sign of occurrence of abnormal discharge. Even when an abnormal discharge prediction signal is output or when an abnormal discharge prevention signal is periodically output to prevent the occurrence of abnormal discharge, the control function of the control circuit continues to operate without stopping. A control signal is generated, and the abnormal discharge detection signal, the abnormal discharge prediction signal, or the abnormal discharge prevention signal is output from the control circuit. A signal is blocked from passing through the control terminal of the switching semiconductor element for a preset passage prohibition period, and the switching semiconductor element is turned off for the passage prohibition period regardless of the control signal of the control circuit. A method of supplying power to a vacuum apparatus is provided, wherein the inverter immediately performs a steady operation as the control signal passes through a control terminal of the switching semiconductor element as the passage prohibition period elapses.

  In an eighth aspect based on the seventh aspect, the abnormal discharge prevention device operates and a period in which a reverse voltage is applied to the vacuum load or a period in which both ends of the vacuum load are short-circuited is There is provided a method for supplying power to a vacuum apparatus, wherein a DC power supply does not output, and the DC power supply immediately outputs a steady DC output power as the passage prohibition period elapses.

A ninth aspect of the invention, in the seventh invention or the eighth aspect of the present invention, the passage prohibition period is at 100μs or less from 10 [mu] s, the response time of the control function is characterized by longer than the passing prohibition period Provided is a power supply method for a vacuum apparatus.

  In order to solve the above-described problems, the first invention can minimize the current flowing from the DC power supply device to the semiconductor switch of the abnormal discharge prevention device when the abnormal discharge prevention function is activated, thereby preventing abnormal discharge. The apparatus can be reduced in cost, reduced in size and weight, and the current flowing through the vacuum load is reduced immediately after the abnormal discharge disappears, so the adverse effect on the load can be reduced. Further, the DC power supply device can output steady DC power immediately after the passage prohibition period in which the inverter stops.

  According to the second and third inventions, in addition to the effects of the first invention, the output voltage of the DC power supply device is exceeded immediately after the passage prohibition period in which the semiconductor switch for preventing abnormal discharge is turned off. Not only can the shoot be prevented, but also an overshoot of the current that starts to flow into the vacuum load can be prevented.

  According to the fourth aspect of the invention, in addition to the effects exhibited by the first to third aspects of the invention, even if the control circuit has a high-speed control response characteristic, the semiconductor that performs an abnormal discharge prevention function Overshoot of the output voltage of the DC power supply device immediately after the passage prohibition period when the switch is turned off can be prevented.

  According to the fifth invention, in addition to the effects of the first to fourth inventions, when the inverter stops operating, the output power supplied from the DC power supply device is rapidly reduced. Can do.

  According to the sixth invention, in addition to the effects of the first to fifth inventions, not only the occurrence of abnormal discharge is detected, but also the occurrence of abnormal discharge is predicted in a short time. The abnormal discharge in the vacuum load can be extinguished, or the electric discharge can be extinguished before the abnormal discharge is reached.

  According to the seventh aspect, when the abnormal discharge prevention function works, the current flowing from the DC power supply device to the semiconductor switch of the abnormal discharge prevention device can be minimized, and the abnormal discharge prevention device can be reduced in cost and size. It is possible to reduce the weight and prevent overshooting of the current flowing through the vacuum load immediately after the disappearance of the abnormal discharge, so that it is possible to provide a power supply method that can reduce the adverse effect on the load. Further, it is possible to output steady DC power immediately after the passage prohibition period in which the inverter stops.

  According to the eighth aspect of the invention, in addition to the effect exhibited by the seventh aspect, a power supply method capable of outputting steady DC power immediately after the passage prohibition period in which the inverter stops is provided.

  According to the ninth aspect of the invention, in addition to the effect of the eighth aspect of the invention, it is possible to prevent overshoot of the output voltage of the DC power supply device immediately after the passage prohibition period when the semiconductor switch for preventing abnormal discharge is turned off. Provided is a method for supplying power.

[Embodiment 1]
A vacuum apparatus 100 according to the first embodiment of the present invention will be described with reference to FIGS. 1 and 2. This vacuum device 100 is roughly composed of a DC power supply device 1, an abnormal discharge prevention device 30 and a vacuum load 50. The DC power supply 1 is connected to a three-phase full-wave rectifier 11 that converts three-phase AC power from a commercial three-phase AC input power supply 10 into DC power, an inverter 12 that converts the DC power into high-frequency AC power, and an inverter 12. The transformer 13 having the primary winding 13A and the secondary winding 13B, the output side rectifier circuit 14 connected to the secondary winding 13B, and the smoothing capacitor connected between the output terminals of the output side rectifier circuit 14 15, a control circuit 16 for supplying a control signal to the inverter 12, a gate circuit 17 connected between the inverter 12 and the control circuit 16, DC output terminals 18 and 19, and the DC output terminals 18 and 19 to the vacuum load 50 A load current detector 20 that detects a flowing current, a load voltage detection circuit 21, a load current detection signal from the load current detector 20, and a load voltage from the load voltage detection circuit 21 The multiplication circuit 22 that multiplies the output signal and outputs a load power detection signal proportional to the load power of the vacuum load 50, and outputs an error amplification signal between the load power detection signal and the reference power value of the power reference source 23. It consists of an error amplifier 24 and the like. Of course, the AC input power supply 10 may be a single-phase AC power supply. In this case, the rectifier 11 has a circuit configuration for converting single-phase alternating current into direct current.

  The inverter 12 is a full-bridge inverter formed by connecting four switching semiconductor elements 12A, 12B, 12C, and 12D such as IGBTs or MOSFETs in a full-bridge configuration. The switching semiconductor elements 12A, 12B, 12C, and 12D have body diodes (parasitic diodes) 12a, 12b, 12c, and 12d, respectively. Here, the inverter 12 may of course be an inverter having another circuit configuration, such as a half-bridge inverter in which two capacitors and two switching semiconductor elements are connected in a full bridge configuration. When the switching semiconductor elements 12A to 12D are semiconductor elements that do not include the body diodes 12a to 12d, individual diodes that operate the body diodes may be connected in antiparallel. The control circuit 16 continues to output a pulse width control signal for controlling the pulse width of the switching semiconductor elements 12A to 12D even when abnormal discharge occurs. The gate circuit 17 includes four AND gates 17A, 17B, 17C, and 17D. The AND gates 17A, 17B, 17C, and 17D pass the positive control signal to the inverter 12 when receiving a positive control signal from the control circuit 16 and a positive signal from the abnormal discharge prevention device 30. When receiving a negative signal related to abnormal discharge, the AND gates 17A, 17B, 17C, and 17D block the positive control signal from the control circuit 16 and do not pass it. In this vacuum apparatus 100, the inverter 12, the transformer 13, the control circuit 16, and the gate circuit 17 constitute an inverter apparatus. The switching semiconductor elements 12A and 12B and 12C and 12D operate alternately in opposite phases. Although not shown, in practice, the transmission and reception of electrical signals between the control circuit 16 and the switching semiconductor elements 12A, 12B, 12C, and 12D is insulated and transmitted.

  The abnormal discharge prevention device 30 connected to the DC output terminals 18 and 19 of the DC power supply device 1 is connected in series with the vacuum load 50 between the DC output terminals 18 and 19 to function the load current continuously and arc discharge. A current stabilizing inductance element 31 that functions to suppress an abrupt increase in current when such an abnormal discharge (hereinafter referred to as abnormal discharge) occurs, and is connected across both ends of the vacuum load 50; and A semiconductor switch 32 and a reverse polarity power supply 33 connected in series with each other, an insulation transmission circuit 34 for transmitting a signal while electrically insulating the low voltage side and the high voltage side, and an abnormal discharge caused by being connected to both ends of the vacuum load 50 Or when an abnormal discharge detection signal or an abnormal discharge prediction signal is received from the abnormal discharge detection circuit 35. Comprising a pulse generating circuit 36 for generating a pulse signal S2 of the scan signal S1 and L-level (0). Here, the reverse polarity voltage of the reverse polarity power supply 33 refers to a voltage having a polarity opposite to that of the steady voltage (illustrated) in the vacuum load 50. The reverse polarity voltage of the reverse polarity power supply 33 is about 10 to 20% of the DC output voltage of the DC power supply device 1. For example, when the DC output voltage of the DC power supply device 1 is −500V, it is about + 100V. The reverse polarity power source 33 is known to be composed of a capacitor (not shown) that is charged with the polarity shown and a charging circuit that charges the capacitor.

  First, the abnormal discharge detection circuit 35 will be described before describing the operation of the vacuum apparatus 100. The detailed configuration of the abnormal discharge detection circuit 35 is not a requirement of the present invention. Since it is described in the specification of No. 097848, the configuration will not be shown and will be described in the following. As a first basic example of the abnormal discharge detection circuit 35, when an abnormal discharge occurs in the vacuum load 50, the load voltage rapidly decreases and drops below the set voltage, and the load current increases rapidly. Therefore, the abnormal discharge detection signal is generated as a result of occurrence of abnormal discharge when this condition is satisfied. As a second example, when the possibility of abnormal discharge occurring in the vacuum load 50 or the occurrence of abnormal discharge is large, the decrease rate of the load voltage increases. Therefore, the voltage decrease rate is detected, and the voltage decrease rate is When the set value is exceeded, an abnormal discharge prediction signal is output immediately before occurrence of abnormal discharge, or an abnormal discharge detection signal is generated as abnormal discharge has occurred. This point will be described in more detail. When the vacuum load 50 is magnetron sputtering, the rate of decrease of the voltage of the vacuum load 50, that is, the rate of decrease is small in a stable state in which abnormal discharge is unlikely to occur during plasma operation. Therefore, no abnormal discharge prediction signal or abnormal discharge detection signal is generated.

  However, when a target (not shown) of the vacuum load 50 is easily charged and abnormal discharge is likely to occur, a minute discharge that does not yet transfer to the abnormal discharge occurs. Since the current stabilizing inductance element 31 exists, an increase in current causes the voltage of the vacuum load 50 to drop in a short time. Thus, the state where the voltage drop of the vacuum load 50 is caused by the minute discharge is an unstable state in which the vacuum load 50 is likely to shift from the plasma state to the abnormal discharge state, and may shift to the abnormal discharge. Therefore, the unstable state that easily shifts to the abnormal discharge state is regarded as a precursor phenomenon of occurrence of the abnormal discharge, and the voltage drop rate of the vacuum load 50 is detected as the precursor phenomenon, and the detection voltage indicating the voltage drop rate is If it becomes higher than the reference value, that is, the set value, an abnormal discharge prediction signal is generated on the assumption that there is a high risk of shifting to abnormal discharge.

  As a third example of the abnormal discharge detection method, the voltage of the load voltage 50 is sampled with a small time width every short fixed time, the sampled voltage is temporarily stored, and the stored sampling voltage value is then sampled. A difference voltage is obtained by subtracting from the value, and if the difference voltage is larger than a set value, an abnormal discharge prediction signal is generated with a high risk of shifting to abnormal discharge. In the case of this method, it may be performed in the same manner using the difference in output current, and more reliable prediction of abnormal discharge can be detected by combining the voltage difference and the current difference. As a fourth example of the abnormal discharge detection method, the second order differential is obtained by subtracting the voltage difference obtained in the third example from the next voltage difference, that is, subtracting the voltage difference immediately before from the now obtained voltage difference. When the signal is obtained and the secondary differential signal is larger than the set value, an abnormal discharge prediction signal may be generated. In this case, it is possible to detect the occurrence of abnormal discharge more quickly than in the third example. Although the typical detection method of the abnormal discharge detection circuit 35 has been described above, other detection methods may be used as a matter of course.

  Next, the operation of the vacuum apparatus 100 will be described. In a state where the DC power supply device 1 outputs a rated DC output power between its DC output terminals 18 and 19, current flows from the DC output terminal 18 to the vacuum load 50, the load current detector 20, and the current stabilizing inductance element. 31 flows to the DC output terminal 19 and the voltage of the vacuum load 50 is in a high state. In this state, the abnormal discharge detection circuit 35 does not generate the abnormal discharge detection signal and the abnormal discharge prediction signal, and therefore the signal S1 generated by the pulse generation circuit 36 is at the L level and the signal S2 is at the H level. . The insulation transmission circuit 34 transmits the L level signal S1 to the gate of the semiconductor switch 32 while insulating, and the semiconductor switch 32 is in the OFF state. On the other hand, the H level signal S2 from the pulse generation circuit 36 is input to one input terminal of each of the AND gates 17A to 17D in the gate circuit 17. An H level pulse width control signal from the control circuit 16 is input to the other input terminal of each of the AND gates 17A to 17D. Therefore, when each of the AND gates 17A to 17D receives the H level signal S2, the H level pulse width control signal from the control circuit 16 is directly passed to the gates of the respective switching semiconductor elements 12A to 12D, and the inverter 12 Are pulse width controlled. As is well known, the control circuit 16 receives an error amplification signal equal to the difference between the load power detection signal output from the multiplication circuit 22 and the reference power value of the power reference source 23 from the error amplifier 24, and A pulse width control signal for controlling the inverter 12 is output so that the load power detection signal is equal to the reference power value.

  Next, a case where the abnormal discharge detection circuit 35 outputs the abnormal discharge detection signal or the abnormal discharge prediction signal as described above to the pulse generation circuit 36 will be described. The pulse generation circuit 36 receives the signal and outputs an H level signal S1, and switches the signal S2 that has been at the H level so far to an L level signal level and outputs it to the gate circuit 17. At this time, the control circuit 16 receives the error amplification signal from the error amplifier 24, and outputs a pulse width control signal so that the load power detection signal output from the multiplication circuit 22 is equal to the reference power value of the power reference source 23. It is output to the gate circuit 17. However, since one input terminal of each of the AND gates 17A to 17D in the gate circuit 17 has an L level signal level, each AND gate 17A to 17D receives an H level pulse width control signal from the control circuit 16. Do not pass. That is, when the abnormal discharge detection circuit 35 generates the abnormal discharge detection signal and the abnormal discharge prediction signal, the pulse width control signal is supplied to the inverter 2 even if the control circuit 16 operates normally and sends out the pulse width control signal. Therefore, all the switching semiconductor elements 12A to 12D are turned off, and the output of the DC power supply device 1 is stopped.

  On the other hand, the H level signal S1 from the pulse generation circuit 36 is a pulse signal having a pulse width of, for example, about 20 μs, and is applied to the gate of the semiconductor switch 32 through the insulation transmission circuit 34 to turn on the semiconductor switch 32. As the semiconductor switch 32 is turned on, the reverse polarity voltage of the reverse polarity power supply 33 is applied to the vacuum load 50, so that the abnormal discharge disappears. At this time, the current that has been flowing from one DC output terminal 18 of the DC power supply device 1 to the other DC output terminal 19 through the vacuum load 50 and the current stabilizing inductance element 31 until the semiconductor switch 32 is turned on. Then, it flows through the semiconductor switch 32. In the present invention, as described above, when the abnormal discharge detection circuit 35 outputs the abnormal discharge detection signal or the abnormal discharge prediction signal, the DC power supply device 1 stops supplying the output. The current supplied from the power supply device 1 is sufficiently small. In particular, since the vacuum device 100 uses a so-called capacitor input type rectifier circuit that does not include a smoothing inductor at the output of the DC power supply device 1, energy stored in the smoothing inductor is not supplied. Since the energy stored in the leakage inductance of the transformer 13 is fed back to the power supply side through the body diodes (parasitic diodes) 12a to 12d of the switching semiconductor elements 12A to 12D in the inverter 12, the peak value of the current flowing through the semiconductor switch 32 Can be sufficiently reduced as compared with the prior art. In this embodiment, a leakage inductance (not shown) of the transformer 13 is used as a current limiting element of an inverter having a capacitor input type rectifier circuit as a load, and the charging current of the smoothing capacitor 15 is caused by this leakage inductance. Can be limited.

This point will be described in more detail with reference to FIG. FIG. 2A shows a signal S1 output from the pulse generation circuit 36 to the semiconductor switch 32 when the abnormal discharge detection circuit 35 generates an abnormal discharge detection signal or an abnormal discharge prediction signal. FIG. The signal S2 that the pulse generation circuit 36 outputs to the gate circuit 17 is sometimes shown. FIG. 2 (C) shows the voltage waveform Vo of the vacuum load 50 when the semiconductor switch 32 is turned on, FIG. 2 (D) shows the current waveform I _L of the inductance element 31 for current regulation. Figure 2 (E) shows a waveform of the load current flowing through the vacuum load 50, FIG. 2 (F) shows the current waveform I _S flowing through the semiconductor switch 32. A solid line indicates the case of the present invention, and a broken line indicates the conventional case.

  In a steady operation state before time t1 when an abnormal discharge such as arc discharge occurs, the stable plasma current Io shown in FIG. 2D is transferred from the DC power supply device 1 to the vacuum load 50 and the current stabilizing inductance element 31. It continues to flow. When the abnormal discharge detection circuit 35 outputs an abnormal discharge detection signal or an abnormal discharge prediction signal at time t1, the pulse generation circuit 36 generates an H-level signal S1 as shown in FIG. The signal S2 that changes from the H level to the L level as shown in FIG. If the pulse width of the signal S1 is, for example, 20 μs, which is the time required to extinguish the abnormal discharge, the signal S1 is a predetermined H level voltage from time t1 to time t2 20 μs later, and at time t2. It becomes L level after progress. Further, the signal S2 becomes L level only for a period of 20 μs from time t1 to time t2, and returns to the original H level after time t2. When the semiconductor switch 32 is turned on in response to the H level signal S1, a reverse polarity voltage is applied to the vacuum load 50 from the reverse polarity power source 33. The voltage of the vacuum load 50 is shown in FIG. Thus, the positive voltage E is obtained. Therefore, it is understood that the abnormal discharge generated in the vacuum load 50 or the discharge state having a high possibility of causing the abnormal discharge disappears in the period of 20 μs.

In the present invention, the current flowing through the current stabilizing inductance element 31 in the period from the time t1 to the time t2 has a substantially constant waveform as shown by the solid line in FIG. 2D. The waveform increases. In the present invention, as described above, the gate circuit 17 receives the signal S2 as shown in FIG. 2B from the pulse generation circuit 36, so that only the period T from time t1 to time t2, that is, the passage prohibition period T. Since the pal width control signal from the control circuit 16 is not passed through the inverter 12, the inverter 12 is off during this passage prohibition period T, and the DC power supply device 1 does not output. The DC power supply device 1 is a capacitor input type, and is not substantially affected by the inductance contained in the DC power supply device 1, and during this passage prohibition period, the charging charge of the smoothing capacitor 15 is only rapidly discharged. As shown by the solid line in FIG. 2 (D), it returns to the original state with a slight increase immediately after time t1. In this regard, in the conventional device in which the inverter 12 is not turned off, the DC power supply device 1 supplies the output power during the period T from the time t1 to the time t2, so that the current stabilizing inductance element is shown by the broken line in FIG. The current 31 is increased by ΔI _L = ET / L with the current I _L flowing so far as an initial current, and becomes a current of (I _L + ΔI _L ). Here, E is a voltage equal to the sum of the output voltage of the DC power supply device 1 and the voltage of the reverse polarity power supply 33, and L is the inductance of the current stabilizing inductance element 31. Therefore, in the passage prohibition period T (t1 to t2), the current flowing through the current stabilizing inductance element 31 flows to the semiconductor switch 32 and flows to the vacuum load 50 as shown by the solid line in FIG. load current Io becomes almost zero after time t1, the peak value of the current I _S flowing through the semiconductor switch 32 as indicated by a broken line in FIG. 2 (F) is increased to (I L ₊ ΔI _L), in the present invention Does not substantially increase as shown by the solid line.

In the case of the conventional power supply device, a smoothing inductor (not shown) is provided between the output side rectifier circuit 14 of the DC output terminals 18 and 19 and the smoothing capacitor 15 and is stored in the smoothing inductor. since it has energy inverter 12 continues to be discharged to the smoothing capacitor 15 is also turned off, the voltage of the smoothing capacitor 15 is not decreased, has the disadvantage that a larger increment [Delta] I _L of the current I _L Yes. As can be seen from the broken line in FIG. 2 (E), since the current flowing through the vacuum load 50 immediately after the semiconductor switch 32 is turned off, the abnormal discharge again occurs when the plasma remains at a certain level in the vacuum load 50. May occur.

  In the vacuum device 100 of the first embodiment, when the semiconductor switch 32 is turned on, almost no power is supplied from the DC power supply device 1, so that the current flowing through the semiconductor switch 32 has been flowing through the current stabilizing inductance element 31 until now. Therefore, it is possible to use the semiconductor switch 32 having a smaller current capacity as compared with the conventional case, and it is possible to reduce the cost of the abnormal discharge prevention device 30 and to reduce the size and weight. Further, when a semiconductor switch having a current capacity comparable to that of the conventional device is used, the reverse polarity voltage of the reverse polarity power source 33 can be further increased, so that abnormal discharge can be eliminated more quickly and reliably. What is important here is that the control circuit 16 receives the feedback signal from the error amplifier 24 and operates normally during the period T from time t1 to time t2, that is, the passage prohibition period T. 2 (B), when the signal S2 from the pulse generation circuit 36 returns from the L level to the H level at the time t2, the gate circuit 17 passes the pulse width control signal from the control circuit 16 as it is, and immediately the inverter 12 Starts operation with pulse width control and performs constant power control. Therefore, even if a soft start control function is provided to prevent a large inrush current from flowing when the DC power supply device 1 is started, the DC power supply device 1 performs normal operation immediately after the passage prohibition period T elapses, and the constant power Can be output.

  In the first embodiment, it is also an important factor that the control circuit 16 has a response time longer than the passage prohibition period T, that is, the response speed is slow. In the above description, the passage prohibition period T is set to 20 μs, for example. However, the passage prohibition period T is at most (at most) in the range of 10 to 100 μs, and the frequency response of the control circuit 16 is longer than the passage prohibition period T. Preferably, if set to 1 ms or more, the control circuit 16 hardly responds to the interruption of the control signal in the passage prohibition period T in the range of 10 to 100 μs, and the control circuit 16 immediately follows the passage prohibition period T. It works almost normally. Here, the response time of the control circuit 16 is generally composed of various arithmetic circuits, capacitors, and the like (not shown), and an output signal for the input signal of the control circuit 16 determined by these elements, here a pulse This is the delay time of the width control signal, that is, the response time. The response time is also determined by the error amplifier 24 input to the control circuit 16 and the integration element coupled thereto. If the response time is longer than the passage prohibition period T, preferably 1 ms or longer, the pulse width control signal output from the control circuit 16 immediately after the passage prohibition period T elapses does not have a substantial adverse effect.

  On the other hand, when the response speed of the control circuit 16 is high, for example, when the response time is as short as several times less than the passage prohibition period T, it responds to the output of the DC power supply device 1 being forcibly turned off. As a result, problems such as overshooting of the output of the DC power supply device 1 immediately after the passage prohibition period T may occur. In order to avoid the occurrence of this overshoot, the overshoot can be minimized by reducing the steady reference power value of the power reference source 23 during the passage prohibition period T. In this case, the pulse generation circuit 36 applies a third signal having the same pulse width as that of the passage prohibition period T to the power reference source 23 in synchronization with the signal S1, and the power reference source 23 receives the third signal. The steady reference power value may be reduced to a predetermined value during the passage prohibition period T.

  A modification of the vacuum device 100 is not shown, but, for example, has a circuit configuration substantially the same as that of the abnormal discharge detection circuit 35 of the vacuum device 100 at both ends of the current stabilization inductance element 31 and performs the same function. A configuration including the illustrated abnormal discharge detection circuit may be employed. The rest is almost the same as the configuration of the vacuum apparatus 100 and the operation is also the same, so the points different from the vacuum apparatus 100 will be mainly described with reference to FIG. In a state where there is a high possibility of occurrence of abnormal discharge or abnormal discharge in the vacuum load 50, the current flowing through the current stabilizing inductance element 31 increases. Along with this, the voltage of the current stabilizing inductance element 31 also increases. If the increase is rapid, abnormal discharge is likely to occur. Therefore, an abnormal discharge detection circuit (not shown) connected to both ends of the current stabilizing inductance element 31 performs abnormal discharge in the same manner as described above when the voltage rising at an increase rate corresponding to the current increase rate becomes equal to or higher than the reference voltage. A detection signal or an abnormal discharge prediction signal is output. Since others are the same as the vacuum apparatus 100, description is abbreviate | omitted.

  As another modification, the pulse generation circuit 36 in FIG. 1 drives the semiconductor switch 32 at a predetermined cycle, and the semiconductor switch 32 is turned on regardless of the occurrence of abnormal discharge to periodically reverse the vacuum load 50. In the case where only the polarity voltage is applied, and even when the reverse polarity voltage is periodically applied to the vacuum load 50 as described above, there may be a case where abnormal discharge occurs. Therefore, the reverse polarity voltage is periodically applied to the vacuum load 50. In some cases, an abnormal discharge is detected as in the vacuum device 100 and the above countermeasure is taken. Even in such a case, the period during which the semiconductor switch 32 is turned on is a passage prohibition period, and the gate circuit 17 does not pass the control signal even though the control circuit 16 operates to generate the control signal. The inverter 12 is turned off.

  Furthermore, although the reverse polarity power supply 33 is used in the first embodiment and the modification, the semiconductor switch 32 is not applied without applying the reverse polarity voltage without using the reverse polarity power supply 33 when the load impedance is relatively large. There are a method of turning on the vacuum load 50 and preventing the occurrence of abnormal discharge, or a method of extinguishing the abnormal discharge. The present invention can be similarly applied to such a method, and a period during which the semiconductor switch 32 is turned on is defined as a passage prohibition period so that the control signal from the control circuit 16 is not allowed to pass only during the passage prohibition period. Then, the same effect as in the first embodiment can be obtained.

  In other words, the present invention provides a control circuit that performs a normal operation when the semiconductor switch 32 in the abnormal discharge prevention device 30 is turned on regardless of the type of detection method for abnormal discharge occurrence or the method for predicting the occurrence of abnormal discharge. It is important to cut off the passage of the control signal generated from the capacitor, and it is desirable that the capacitor input type DC power supply device not include a smoothing inductor on the output side. Further, it is preferable that the control circuit for generating a control signal such as a pulse width control signal has an operation response time longer than the passage prohibition period in which the semiconductor switch of the abnormal discharge prevention device is turned on. Furthermore, when the control circuit has a high-speed response, that is, an operation response time is short, it is preferable to reduce the reference power value compared with the load power detection signal only during the passage prohibition period. In the first embodiment, the gate circuit 17 is composed of the four AND gates 17A to 17D. However, the present invention is not limited to this, and the control signal from the control circuit is cut off or absorbed by the signal from the pulse generation circuit. Of course, the circuit configuration may be zero.

It is a figure which shows the vacuum apparatus 100 which concerns on Embodiment 1 of this invention. It is a figure which shows the voltage waveform or current waveform of each part in the vacuum circuit 100 of this invention, and a conventional apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... AC input power source 12 ... Inverter 12A-12D ... Switching semiconductor element 13 ... Transformer 14 ... Output side rectifier circuit 15 ... Smoothing capacitor 16 ... Control circuit 17 ... Gate circuits 17A to 17D AND circuits 18, 19 DC output terminals 20 Load current detector 21 Load voltage detection circuit 22 Multiplication circuit 23 Power reference source 24 ... Error amplifier 30 ... Abnormal discharge prevention device 31 ... Inductive element for current stabilization 32 ... Semiconductor switch 33 ... Reverse polarity power supply 34 ... Insulation transmission circuit 35 ... Abnormal discharge detection Circuit 36... Pulse generation circuit 50... Vacuum load 100.

Claims (9)

In a vacuum apparatus comprising: a vacuum load; a direct-current power supply that supplies power to the vacuum load; and an abnormal discharge prevention device that is provided between the direct-current power supply and the vacuum load to prevent the occurrence of abnormal discharge.
The DC power supply device is connected to a transformer, an inverter connected to a primary winding of the transformer, and includes a switching semiconductor element that controls power supplied to the vacuum load, and to a secondary winding of the transformer. A rectifier circuit; a control circuit that provides a control signal for controlling the switching semiconductor element; and a gate circuit provided between the control circuit and a control terminal of the switching semiconductor element.
The abnormal discharge prevention device outputs an abnormal discharge detection signal when the occurrence of abnormal discharge in the vacuum load is detected, or outputs an abnormal discharge prediction signal when a sign of occurrence of abnormal discharge is detected, or in the vacuum load Output an abnormal discharge prevention signal periodically generated to prevent the occurrence of abnormal discharge,
The gate circuit is arranged between the control circuit and a control terminal of the switching semiconductor element when the abnormal discharge prevention device outputs the abnormal discharge detection signal, the abnormal discharge prediction signal, or the abnormal discharge prevention signal. The control signal is blocked only during a preset passage prohibition period, and the control signal is not passed through the control terminal of the switching semiconductor element during the passage prohibition period. A vacuum apparatus characterized by being passed through a control terminal of an element. In claim 1,
The passage prohibition period is less than 100μs from 10 [mu] s, the response time of the control circuit vacuum and wherein the longer than the passing prohibition period. In claim 1 or claim 2,
The passage prohibition period is a period substantially equal to a pulse width of a signal formed when the abnormal discharge detection signal, the abnormal discharge prediction signal, or the abnormal discharge prevention signal is generated. apparatus. In any one of Claims 1 thru | or 3,
A power reference source having a reference power value compared with a load power detection signal proportional to the load power of the vacuum load, and an error amplification signal equal to the difference between the load power detection signal and the reference power value to the control circuit An output error amplifier,
The vacuum apparatus according to claim 1, wherein the power reference source provides a reference power value lower than the reference power value in a steady state during the passage prohibition period. In any one of Claim 1 thru | or 4,
The rectifier circuit is a capacitor input type having a smoothing capacitor between output terminals and substantially not having a smoothing inductor. In any one of Claims 1 thru | or 5,
The abnormal discharge prevention device is periodically generated when the occurrence of abnormal discharge in the vacuum load is detected, when a sign of occurrence of abnormal discharge is detected, or in order to prevent the occurrence of abnormal discharge in the vacuum load. A vacuum device comprising: a semiconductor switch that applies a reverse polarity voltage to the vacuum load or short-circuits both ends of the vacuum load when outputting an abnormal discharge prevention signal. A DC power supply device including a vacuum load, an inverter including a switching semiconductor element that controls electric power supplied to the vacuum load, and a control circuit that controls the inverter, and provided between the DC power supply device and the vacuum load. In the method of supplying power to the vacuum device comprising the abnormal discharge prevention device,
When the abnormal discharge prevention device outputs an abnormal discharge detection signal indicating the occurrence of abnormal discharge or an abnormal discharge prediction signal indicating a sign of the occurrence of abnormal discharge, or periodically in order to prevent the occurrence of abnormal discharge Even when an abnormal discharge prevention signal is output, the control function of the control circuit continues to operate without stopping and generates a control signal,
The abnormal discharge detection signal, the abnormal discharge prediction signal, or the abnormal discharge prevention signal is transmitted from the control circuit to the control terminal of the switching semiconductor element for a preset passage prohibition period. Shut off
The switching semiconductor element is turned off only during the passage prohibition period regardless of the control signal of the control circuit,
As the passage prohibition period elapses, the inverter performs a steady operation immediately after the control signal passes through the control terminal of the switching semiconductor element. In claim 7,
During the period in which the abnormal discharge prevention device is operated and a reverse voltage is applied to the vacuum load, or the both ends of the vacuum load are short-circuited, the DC power supply device does not output, and the passage prohibition period A power supply method for a vacuum apparatus, wherein the DC power supply device immediately outputs steady DC output power as time passes. In claim 7 or claim 8,
The passage prohibition period is at 100μs or less from 10 [mu] s, the response time of the control function power supply method of a vacuum device, characterized in that longer than the passing prohibition period.

Images