JP5172135B2 - Vacuum equipment - Google Patents

Description

  The present invention relates to a vacuum apparatus including an abnormal discharge prevention device that prevents or suppresses the occurrence of abnormal discharge in a vacuum load, such as a sputtering apparatus, an etching apparatus, a PVD apparatus, and an electron beam vapor deposition apparatus that use plasma generated in a vacuum. .

  Vacuum loads such as a sputtering apparatus, an etching apparatus, a PVD apparatus, and an electron beam evaporation apparatus that generate plasma in a vacuum and process or process using the plasma have been used in a wide range of fields. In such a vacuum load, it is already known that an abnormal discharge occurs when the impedance between the electrodes decreases for some reason or the electrodes are short-circuited by a conductive foreign matter. Yes. When such abnormal discharge occurs, there is a problem that a substrate material such as liquid crystal during sputtering is caused particularly in a sputtering apparatus, resulting in a decrease in product yield. In an electron beam evaporation apparatus, a filament is formed by discharge energy. There are problems such as disconnection. In order to solve such a problem, various abnormal discharge prevention circuits that prevent or suppress abnormal discharge have already been proposed.For example, a circuit configuration is relatively simple and an effective abnormal discharge prevention circuit is applied to a vacuum load. By switching on the semiconductor switch elements connected in parallel periodically or when an abnormal discharge occurs, a pulse voltage of reverse polarity from the reverse voltage power supply is applied to the vacuum load to prevent or generate abnormal discharge. There has also been proposed a technique for quickly eliminating the abnormal discharge (for example, see Patent Documents 1 to 3).

Thus, in the case of a circuit configuration in which the semiconductor switch element is turned on for a short time periodically or when an abnormal discharge occurs, particularly when the semiconductor switch element is turned off, the current that has been flowing through the semiconductor switch element until then is reduced. When suddenly shut off, a considerably high voltage is applied to the semiconductor switch element due to the current flowing through the main inductor for stabilizing the current flowing in the vacuum load, the power loss of the semiconductor switch element is greatly increased, and heat is generated. Since there is a risk of breakage, a circuit for preventing this has already been proposed (see, for example, Patent Document 4). In Patent Document 4, a snubber circuit including a capacitor, a diode, and a discharging resistor is connected in parallel to a semiconductor switch element, and surge energy generated when the semiconductor switch element is turned off is absorbed by the snubber circuit.
Japanese Patent Laid-Open No. 07-197258 Japanese Patent Laid-Open No. 08-311647 JP 2005-151612 A JP 2004007885 A

  As described above, in the vacuum apparatus provided with the abnormal discharge occurrence prevention function disclosed in Patent Document 4, in order to prevent the occurrence of abnormal discharge or to quickly extinguish the generated abnormal discharge. The semiconductor switch element is turned on, and a reverse voltage is applied to the vacuum load from the reverse voltage power source. In this case, a large voltage is applied to the semiconductor switch element when the semiconductor switch element is turned off, so this is reduced. For this purpose, surge energy generated when the semiconductor switch element is turned off is collected in a snubber circuit and consumed by the resistor. However, in this case, power loss in the snubber circuit becomes large. The heat generated by the power loss can be processed by air cooling with a fan or the like, but it is not preferable from the viewpoint of environmental problems, and causes the temperature in the vacuum apparatus to rise.

  In order to solve the problems of the conventional vacuum device, the present invention absorbs energy from the main inductor and stores it in the capacitor when the semiconductor switch element is turned off, and then discharges from the capacitor when the semiconductor switch element is turned on. Electric charge is temporarily stored in the inductance element as magnetic energy, and when the semiconductor switch element is turned off, the magnetic energy stored in the inductance element is fed back to one or both of the reverse voltage power source and the DC power source, thereby suppressing power loss. The main issues are to limit the temperature rise and to reduce the capacity of the reverse voltage power supply.

A first invention is a DC power supply and a main inductor that will be connected to these in series between the vacuum load, which is connected in parallel across a vacuum load, and the semiconductor switching element and the reverse voltage that will be connected in series with each other A power supply and a control circuit for driving the semiconductor switch element on and off , and when the semiconductor switch element is on , a voltage having a polarity opposite to the output voltage of the DC power supply is applied from the reverse voltage power supply to the vacuum load. in a vacuum apparatus for applying a capacitor the first magnetic energy stored in the main inductor during the oN period of the previous SL semiconductor switching element and the semiconductor switching element is stored is absorbed to charge when turned off, the first one end of the first circuit and the first diode Tsuryu are connected in series when the magnetic energy is absorbed by the capacitor, the said direct current power supply Between the inductor and the other end of the first circuit is connected between the vacuum load and the main inductor is connected in parallel to said main inductor, the capacitor when the semiconductor switching element is turned on the charge that is discharged and the inductance element for storing a second magnetic energy, the reverse voltage supply and the DC power supply to said second magnetic energy stored in the inductance element when the semiconductor switching element is turned off from A second circuit in which a second diode to be fed back is connected in series is provided between a connection side of the capacitor and the first diode and a connection side of the semiconductor switch element and the reverse voltage power source. A vacuum apparatus characterized by being connected is provided.

A second invention is a DC power supply and a main inductor that will be connected to these in series between the vacuum load, which is connected in parallel across a vacuum load, and the semiconductor switching element and the reverse voltage that will be connected in series with each other A power supply and a control circuit for driving the semiconductor switch element on and off , and when the semiconductor switch element is on , a voltage having a polarity opposite to the output voltage of the DC power supply is applied from the reverse voltage power supply to the vacuum load. in a vacuum apparatus for applying a capacitor the first magnetic energy stored in the main inductor during the oN period of the previous SL semiconductor switching element and the semiconductor switching element is stored is absorbed to charge when turned off, the first one end of the first circuit and the first diode Tsuryu are connected in series when the magnetic energy is absorbed by the capacitor, the said direct current power supply Between the inductor and the other end of the first circuit is connected between the vacuum load and the main inductor is connected in parallel to said main inductor, the capacitor when the semiconductor switching element is turned on wherein a flyback transformer for storing charge that is discharged as the second magnetic energy, the semiconductor switching element connected in series with the primary winding of the flyback transformer is a charge from the capacitor when on the a second diode flowing through the semiconductor switching element through the primary winding, stored in the flyback transformer the semiconductor switching element connected in series in the off to the secondary winding of the flyback transformer a second circuit having a third diode for feeding back the second magnetic energy being the reverse voltage supply Providing a vacuum apparatus characterized by obtaining.

According to a third invention, in the second invention, when the number of turns of the primary winding of the flyback transformer is n1 and the number of turns of the secondary winding is n2, the number of turns is such that n1 / n2 ≦ 1. A vacuum apparatus characterized by selecting n1 and the number of turns n2 is provided.

According to a fourth invention, in the second invention, the output voltage of the DC power supply is Vm, the output voltage of the reverse voltage power supply is Vr, and the number of turns of the primary winding of the flyback transformer is n1, secondary winding. A vacuum device is provided in which the voltage Vm, the voltage Vr, the number of turns n1, and the number of turns n2 are selected so that Vm + Vr / Vr = n1 / n2 when the number of turns is n2.

In a fifth aspect based on the second aspect , the second circuit is connected in series to another secondary winding provided in the flyback transformer and the other secondary winding. A fourth diode, and the magnetic energy stored in the flyback transformer when the semiconductor switch element is turned off through the second secondary winding and the fourth diode. A vacuum apparatus is provided that returns to

According to a sixth aspect of the present invention, in the fifth aspect , the output voltage of the DC power supply is Vm, the output voltage of the reverse voltage power supply is Vr, the number of turns of the secondary winding of the flyback transformer is n2, Provided is a vacuum device characterized by selecting voltage Vm, voltage Vr, number of turns n2 , and number of turns n3 so that n2 / n3 ≦ Vm / Vr when the number of turns of the secondary winding is n3.

According to a seventh invention, in the first invention, the capacitor of the first circuit and the inductance element of the second circuit resonate, and a quarter of the resonance period Tr of the semiconductor switch element There is provided a vacuum apparatus characterized in that a capacitance of the capacitor and an inductance of the inductance element are selected so as to be equal to or less than an on-time width. According to an eighth aspect of the present invention, in any one of the second to sixth aspects, the capacitor of the first circuit and the flyback transformer resonate, and the resonance period Tr is 1/4. The vacuum device is characterized in that the capacitance of the capacitor and the inductance of the flyback transformer are selected so as to be less than the on-time width of the semiconductor switch element.

According to a ninth invention, in the first or seventh invention , a reverse charge preventing diode is connected in parallel with the capacitor of the first circuit, and the charge of the capacitor is turned on when the semiconductor switch element is on. when the on state of the semiconductor switching element is followed after discharge through the inductance element, the second magnetic energy stored in the inductance element is circulated through said second diode and said semiconductor switching element A vacuum apparatus is provided.

  According to the first aspect of the invention, the energy of the current flowing through the main inductor is stored in the capacitor, the energy is temporarily stored in the inductance element when the semiconductor switch element is turned on, and is fed back to the reverse voltage power supply when the semiconductor switch element is turned off. Therefore, power loss can be reduced, and improvement of the environment, suppression of the temperature rise of the vacuum apparatus, miniaturization of the reverse voltage power source, and the like can be achieved.

According to the second invention, in addition to the effects obtained by the first invention, the energy due to the current flowing through the main inductor by the flyback transformer having the primary winding and the secondary winding is converted to only the reverse voltage power source. Therefore, the reverse voltage power supply can be further downsized.

According to the third invention, in addition to the effect obtained by the second invention, by providing the third diode, current does not flow from the reverse voltage power source through the primary winding of the flyback transformer, Since the feedback is performed through the secondary winding, the voltage of the reverse voltage power supply can be effectively increased, and the capacity of the reverse voltage power supply can be further reduced.

According to the fourth invention, in addition to the effects obtained in the first to third inventions, the energy can be more efficiently fed back to the DC power supply or the reverse voltage power supply. Improvement of the environment, improvement of the environment, suppression of the temperature rise of the vacuum apparatus, etc. can be achieved.

According to the fifth invention, in addition to the effects obtained in the first invention to the fourth invention, energy due to the current flowing through the main inductor can be fed back to the reverse voltage power supply and the DC power supply. The absorbed energy can be used effectively without causing power loss.

According to the sixth invention, in addition to the effects obtained in the fifth invention, the output voltage of the reverse voltage power supply can be clamped to a voltage value corresponding to the output voltage of the DC power supply. Never become.

According to the seventh and eighth aspects of the invention , the energy due to the current flowing through the main inductor can be more efficiently fed back to the reverse voltage power source and the DC power source.

According to the ninth aspect, in addition to the effects obtained in the first aspect or the seventh aspect, the capacitor of the first circuit is not substantially charged with a reverse polarity.

Embodiment 1
First, the vacuum apparatus 100 of Embodiment 1 for implementing this invention with FIG. 1 is demonstrated. 1 shows a circuit configuration of the vacuum apparatus 100, and FIG. 2 is a diagram showing operation waveforms of each part of the vacuum apparatus 100. As shown in FIG. The DC power source 1 is a power source including a rectifier that rectifies AC power of a commercial three-phase AC power source or a single-phase AC power source (not shown), a smoothing filter circuit, and the like. A main inductor 3 for stabilizing the load current is connected in series between the DC power source 1 and a vacuum load 2 such as a sputtering device, an etching device, a PVD device, or an electron beam evaporation device. A reverse voltage power source 4 and a semiconductor switch element 5 connected in series with each other are connected in parallel with the vacuum load 2.

  The reverse voltage power supply 4 is a DC power supply that applies a pulsed reverse voltage suitable for the vacuum load 2 when the semiconductor switch element 5 is turned on, and is a charging circuit for charging the capacitors 4A and 4A with the polarity shown in the figure. 4B and a simple circuit configuration including a diode 4C connected in parallel to the capacitor 4A. The diode 4C functions to prevent the capacitor 4A from being charged to a polarity opposite to the illustrated polarity when the capacitor 4A is discharged until the charge becomes almost zero due to an accident or the like. The semiconductor switch element 5 includes a semiconductor element 5A such as an IGBT or MOSFET or a thyristor which is a voltage-driven semiconductor element, and a parasitic diode or an individual diode 5B. Hereinafter, it is referred to as a diode 5B. The semiconductor switch element 5 is turned on and off by a drive signal from the control circuit 6. In the first embodiment, the control circuit 6 is driven by supplying a drive pulse having a predetermined constant frequency and a constant ON width to the semiconductor switch element 5. However, an abnormal discharge detection circuit or an abnormal discharge occurrence prediction circuit (not shown) is used. Of course, a drive signal may be output when receiving a detection signal from.

  A first circuit S 1 including a capacitor 7 and a first diode 8 connected in series with each other is connected in parallel with the main inductor 3. The first diode 8 functions to prevent the current Ip flowing through the main inductor 3 from being bypassed to the DC power source 1 through the capacitor 7. Between the point A indicating the connection side where the capacitor 7 and the first diode 8 are connected, and the point B indicating the connection side where the reverse voltage power supply 4 and the semiconductor switch element 5 are connected, the second circuit S2 Is connected. The second circuit S2 includes an inductance element 9 and a second diode 10 connected in series with each other. The second diode 10 functions to prevent current from flowing backward from the point B side to the point A side. A reverse charge prevention diode 11 for preventing the capacitor 7 from being charged in reverse is connected in parallel with the capacitor 7. Here, it is assumed that the capacitor 7 has a capacitance C and the inductance element 9 has an inductance L. It is assumed that when the semiconductor switch element 5 is turned on, the capacitor 7 and the inductance element 9 cause a resonance phenomenon in LC.

  Next, the operation of this circuit will be described with reference to FIGS. Since the operations of the vacuum load 2 and the reverse voltage power source 4 and the semiconductor switch element 5 are the same as the conventional ones, the operations and effects of the first circuit S1 and the second circuit S2 accompanying the switching operation of the semiconductor switch element 5 are mainly described. Explained. When the semiconductor switch element 5 is turned on, the load voltage and load current of the vacuum load 2 are as shown in FIGS. 2A and 2B, respectively, according to the output voltage Vr of the reverse voltage power supply 4. Further, as shown in FIG. 2C, when the semiconductor switch element 5 is turned on, the current Ip that has been flowing from the DC power supply 1 through the vacuum load 2 to the main inductor 3 until that time depends on the output voltage Vr of the reverse voltage power supply 4. A current obtained by adding the current flows from the reverse voltage power source 4 to the main inductor 3 through the semiconductor switch element 5.

  In FIG. 2, when the semiconductor switch element 5 is turned off at time t0, the current Ip that has been flowing through the main inductor 3 until then continues to flow as it is due to the inductance action, so that the current flows from the main inductor 3 to the first circuit S1. Through the diode 8 and the capacitor 7 and charge the capacitor 7 with the polarity shown. For example, assuming that the output voltage Vr of the reverse voltage power supply 4 is 100V, the charging voltage of the capacitor 7 is almost 100V. Due to the action of the first circuit S1, a large surge voltage is not generated at both ends of the semiconductor switch element 5 when the semiconductor switch element 5 is turned off. At this time, the diode 8 is reverse-biased by the charging voltage of the capacitor 7, and the diode 10 of the second circuit S2 is also reverse-biased by the sum of the voltage Vm of the DC power supply 1 and the output voltage Vr of the reverse voltage power supply 4. Since it is non-conductive, the charge of the capacitor 7 is maintained without being discharged.

  Next, when the semiconductor switch element 5 is turned on at time t1, the current Ip that has been flowing from the DC power supply 1 through the vacuum load 2 to the main inductor 3 is commutated to the path between the reverse voltage power supply 4 and the semiconductor switch element 5. That is, as described above, the reverse voltage power supply 4 carries the current Ip. At the same time, the electric charge of the capacitor 7 of the first circuit S1 circulates through the inductance element 9, the diode 10 and the semiconductor switch element 5 of the second circuit S2, and stores magnetic energy in the inductance element 9. Here, the energy stored in the inductance is referred to as magnetic energy. At this time, if the inductance L of the inductance element 9 is appropriately selected, during the ON period of the semiconductor switch element 5, the capacitor 7 is discharged until its voltage becomes substantially zero, and almost all the charge of the capacitor 7 is charged. It is stored in the inductance element 9 as magnetic energy.

  The operation in which the electric charge of the capacitor 7 of the first circuit S1 is circulated through the inductance element 9, the diode 10 and the semiconductor switch element 5 of the second circuit S2 is the resonance between the capacitance C of the capacitor 7 and the inductance L of the inductance element 9. Since the phenomenon is accompanied, the current flowing through the inductance element 9 becomes a resonance current as shown in FIG. If the resonance current has a peak value during the ON period of the semiconductor switch element 5, the charge of the capacitor 7 can be efficiently stored as magnetic energy in the inductance element 9. Therefore, 1/4 of the resonance period Tr of the resonance between the capacitance C of the capacitor 7 and the inductance L of the inductance element 9 (Tr = 1 / Fr when the resonance frequency is Fr) is the ON period of the semiconductor switch element 5 (for example, 5 μs) or less, it is desirable to select the capacitance C of the capacitor 7 and the inductance L of the inductance element 9.

By selecting the capacitance C of the capacitor 7 and the inductance L of the inductance element 9 in this way, the discharge current of the capacitor 7, that is, the resonance of the inductance element 9 shown in FIG. The current reaches a peak value at time t2, and at the same time, the voltage of the capacitor 7 becomes almost zero at time t2, and the resonance current is circulated through the diode 10 and the diode 11 without charging the capacitor 7 in reverse polarity until time t3. The When the semiconductor switch element 5 is turned off at time t3, the magnetic energy stored in the inductance element 9 is released from the inductance element 9 through the diode 10, the reverse voltage power supply 4, the DC power supply 1, and the diode 8 , and FIG. As shown in FIG. 4, the current of the inductance element 9 decreases, and all the magnetic energy stored in the inductance element 9 is fed back to the reverse voltage power supply 4 and the DC power supply 1 at time t4, and the capacitor 4A of the reverse voltage power supply 4 is charged. The voltage rises.

  Therefore, the surge generated when the semiconductor switch element 5 is turned off is absorbed by the capacitor 7 and temporarily stored as magnetic energy in the inductance element 9, and all the magnetic energy is fed back to the reverse voltage power supply 4 and the DC power supply 1. The power loss when the semiconductor switch element 5 is turned off is reduced. According to the vacuum load 100 of the first embodiment, since a large surge voltage is not applied across the semiconductor switch element 5 when the semiconductor switch element 5 is turned off, not only can the power loss of the semiconductor switch element be reduced, Since all of the snubber energy is fed back to the reverse voltage power supply 4 and the DC power supply 1, heat generation is small, and adverse effects on the environment can be reduced, and at the same time, the reverse voltage power supply 4, particularly the charging circuit 4B can be downsized.

[Embodiment 2]
Next, a second vacuum apparatus 200 according to Embodiment 2 of the present invention will be described with reference to FIG. In FIG. 3, the same symbols as those shown in FIG. 1 indicate members having the same names. The difference between the second vacuum device 200 and the first vacuum device 100 is that the flyback transformer 30 is mainly used for the second circuit S2 instead of the inductance element, and the others are almost the same. The configuration and operation of the part related to the second circuit S2 will be described. In the second circuit S2, the primary winding N1 of the flyback transformer 30 is connected between the point A and the point B so as to be in series with the diode 10. The secondary winding N2 is connected across both ends of the reverse voltage power supply 4 through the diode 31. The primary winding N1 and the secondary winding N2 have the polarities indicated by black dots, respectively, and have the number of turns n1 and n2.

  When the semiconductor switch element 5 is turned on, the voltage of the capacitor 7 biases the diode 10 in the forward direction to conduct, and the black dot side is positive in the primary winding N1 of the flyback transformer 30 of the second circuit S2. As described above, when the semiconductor switch element 5 is turned off, the charge charged in the capacitor 7 of the first circuit S1 is applied to the primary winding N1, the diode 10 and the semiconductor of the second circuit S2. It is discharged through the switch element 5 and magnetic energy is stored in the inductance L1 of the primary winding N1. The operation so far is almost the same as that of the first vacuum apparatus 100. At this time, since the voltage of the secondary winding N2 is positive on the black dot side, the diode 31 is not turned on with a reverse bias.

Then the semiconductor switching element 5 is turned off Then, the black point side is negative in the secondary winding N2 of the fly-back transformer 30, the voltage of the non-black dot side is positive is induced, stored in the inductance L1 of the primary winding N1 The generated magnetic energy is discharged from the secondary winding N2 to the reverse voltage power source 4 through the diode 31, and charges the capacitor 4A. Also in the second vacuum device 200, the current energy of the main inductor 3 that becomes surge energy when the semiconductor switch element 5 is turned off is absorbed by the capacitor 7, and the charged charge is inductance of the primary winding N1 of the flyback transformer 30. Since the magnetic energy is once stored in L1 and further fed back from the secondary winding N2 to the reverse voltage power supply 4, not only power is lost but heat is not generated, and the charging circuit 4B is reduced in size. There are effects such as Also in the second embodiment, as in the first embodiment, ¼ of the resonance period Tr of the resonance between the capacitance C of the capacitor 7 and the inductance L1 of the primary winding N1 of the flyback transformer 30 is equal to the semiconductor switch element 5. The capacitance C of the capacitor 7 and the inductance L1 of the primary winding N1 of the flyback transformer 30 are selected so that the energy is absorbed by the capacitor 7 so that the energy is absorbed by the primary winding of the flyback transformer 30. Since the inductance L1 of the line N1 can be efficiently stored, the energy absorbed in the first circuit S1 can be efficiently fed back to the reverse voltage power supply 4.

  In the second vacuum device 200, the turn ratio (n1 / n2) between the primary winding N1 and the secondary winding N2 of the flyback transformer 30 is normally selected to be 1. When the semiconductor switch element 5 is turned off, the voltage of the secondary winding N2 of the flyback transformer 30 is clamped to the voltage Vr (for example, 100 V) of the reverse voltage power supply 4 with the non-black dot side being positive. Therefore, when n1 / n2 ≦ 1, the voltage of the primary winding N1 of the flyback transformer 30 has a voltage value equal to or lower than the output voltage Vr of the reverse voltage power supply 4. At this time, the voltage of the cathode of the diode 10 has a voltage value equal to the sum of the output voltage Vm of the DC power supply 1 and the output voltage Vr of the reverse voltage power supply 4, and therefore the diode 10 does not conduct. Therefore, the magnetic energy stored in the inductance L1 of the primary winding N1 is not fed back through the diode 10, but is fed back to the reverse voltage power source 4 through the secondary winding N2, thereby effectively increasing the voltage of the capacitor 4A. .

  In general, in the configuration of the second vacuum device 200, when the load current flowing through the vacuum load 2 is small, that is, when the load is light, not only the output current from the DC power source 1 becomes small but also the reverse voltage power source 4 The output current from becomes smaller. However, the energy (charge) charged in the capacitor 7 of the first circuit S1 depends on the switching frequency of the semiconductor switch element 5, and since the switching frequency is constant, it does not decrease even when the load is light. When the load is light, the magnetic energy of the main inductor 3 is hardly absorbed by the vacuum load 2, so much of it is absorbed by the capacitor 7. Accordingly, when all the energy absorbed in the capacitor 7 is fed back to the reverse voltage power supply 4, a larger power than the power output from the reverse voltage power supply 4 is fed back, so that the reverse voltage power supply having a considerably smaller capacity than the DC power supply 1. There is a risk that the output voltage of 4 rises more than necessary, that is, overcharged.

  In order to solve the problem at the time of the light load described above, the turns ratio (n1 / n2) between the primary winding N1 and the secondary winding N2 of the flyback transformer 30 may be set as follows. . The turns ratio (n1 / n2) is set so that the sum of the output voltage Vm of the DC power supply 1 and the output voltage Vr of the reverse voltage power supply 4 (Vm + Vr) / Vr = n1 / n2. For example, when the output voltage Vm is 500 V and the output voltage Vr is 100 V, n1 / n2 = 6. Since it is easy to understand, in the following description, the output voltage Vm is set to 500V and the output voltage Vr is set to 100V as a specific example. As described above, the electric charge of the capacitor 7 of the first circuit S1 is stored as magnetic energy in the flyback transformer 30 of the second circuit S2 when the semiconductor switch element 5 is turned on next time. When the semiconductor switch element 5 is turned off, the magnetic energy of the flyback transformer 30 is fed back to the reverse voltage power source 4 through the secondary winding N2 to charge the capacitor 4A.

  When the charging of the capacitor 4A proceeds and the voltage of the capacitor 4A exceeds 100V, the voltage of the secondary winding N2 naturally becomes a voltage slightly exceeding 100V. Therefore, the voltage of the primary winding N1 is a DC power supply. 1 exceeds the voltage of 600V, which is the sum of the output voltage of 500V and the output voltage of the reverse voltage power supply 4 of 100V. Therefore, the diode 8 and the diode 10 of the second circuit S2 are forward-biased and become conductive, and the magnetic energy of the flyback transformer 30 is directly fed back to the reverse voltage power supply 4 as in the first embodiment. As a result, it is possible to prevent the output voltage of the reverse voltage power source 4 from increasing at a light load to a set value or more. Note that in a normal load state other than a light load, the discharge of power from the reverse voltage power supply 4 is large and the voltage of the capacitor 4A is lowered. Therefore, the capacitor 4A does not reach 100V due to the feedback energy, and therefore flyback Even if all the magnetic energy stored in the transformer 30 is fed back to the reverse voltage power source 4 through the secondary winding N2, the capacitor 4A will not be overcharged.

  As can be seen from the above, if the turn ratio between the primary winding N1 and the secondary winding N2 of the flyback transformer 30 is set so that (Vm + Vr) / Vr = n1 / n2, the reverse occurs at light load. Although it is possible to prevent an excessive increase in the voltage of the capacitor 4A of the voltage power supply 4, the voltage of the reverse voltage power supply 4 can be prevented by a feedback of magnetic energy stored in the flyback transformer 30 when the load current is large, that is, a heavy load. Cannot be raised. Therefore, although not shown, if necessary, a second secondary winding having a winding number n2 satisfying n1 / n2 ≦ 1 and a second winding having a winding number n2 satisfying (Vm + Vr) / Vr = n1 / n2. A secondary winding may be provided in the flyback transformer. Then, it may be switched to any one of the secondary windings according to the load weight by a switching element (not shown). In this case, a resistor is connected in parallel to the first and second secondary windings.

[Embodiment 3]
Next, a third vacuum apparatus 300 according to the third embodiment of the present invention will be described with reference to FIG. In FIG. 4, the same symbols as those shown in FIGS. 1 and 3 indicate members having the same names. The third vacuum device 300 is different from the first vacuum device 100 or the second vacuum device 200 in that the magnetic energy stored in the inductance of the primary winding N1 of the flyback transformer 40 as described above is separately provided. These are different in that they are fed back to the reverse voltage power source 4 and the direct current power source 1 through the secondary windings. Differences from the vacuum devices 100 and 200 will be mainly described. The flyback transformer 40 of the second circuit S2 has a first secondary winding N2 and a second secondary winding N3. The first secondary winding N2 is connected to both ends of the reverse voltage power source 4 through a diode 31. The second secondary winding N3 is connected across both ends of the DC power supply 1 through the diode 41. The primary winding N1, the first secondary winding N2, and the second secondary winding N3 each have a polarity indicated by a black dot.

  As described in the vacuum device 200, when the load current is small, not only the output current of the DC power supply 1 is reduced, but also the output current of the reverse voltage power supply 4 is reduced. However, the energy charged in the capacitor 7 depends on the switching frequency of the semiconductor switch element and does not decrease even when the load is light. Therefore, when all of the energy charged in the capacitor 7 at the light load is fed back to the reverse voltage power source 4, As described above, there is a risk that the output voltage of the reverse voltage power source 4 may rise more than necessary. In the vacuum device 300, as described above, the electric charge charged in the capacitor 7 of the first circuit S1 is fed back as energy to the reverse voltage power supply 4 preferentially, and when the feedback energy is excessive, the DC power supply 1 is also returned. It is characterized in that the excess voltage is fed back to prevent the output voltage of the reverse voltage power supply 4 from rising more than necessary.

  The number of turns of the first secondary winding N2 of the flyback transformer 40 is n2, the number of turns of the second secondary winding N3 is n3, for example, the output voltage Vm of the DC power supply 1 is 500V, and the output voltage of the reverse voltage power supply 4 Vr is set to 100V. In this vacuum apparatus 300, the turn ratio (n2 / n3) is set to a value substantially equal to or slightly smaller than the voltage ratio (Vm / Vr) between the DC power supply 1 and the reverse voltage power supply 4. Since Vm / Vr = 5 from the above voltage value, if the turns ratio (n2 / n3) is set to about 5, for example, the increase in the output voltage Vr of the reverse voltage power supply 4 is reduced to 1 / of the output voltage Vm of the DC power supply 1. Since this can be limited to 5, this point will be described. As described above, at the stage where the magnetic energy stored in the primary winding N1 of the flyback transformer 40 is released through the secondary winding N2 and the secondary winding N3, the diode 10 is reverse-biased by the output voltage (Vm + Vr). Therefore, the voltage of the capacitor 4A of the reverse voltage power supply 4 is lowered due to the discharge of reverse power. Therefore, when the diode 31 is turned on, the magnetic energy is fed back to the reverse voltage power supply 4, and the capacitor 4A is Charge.

  At this time, if the magnetic energy stored in the primary winding N1 of the flyback transformer 40 is not so large, for example, if the voltage of the first secondary winding N2 is 100 V or less, the turn ratio (n2 / n3) Since the voltage of the second secondary winding N3 is lower than 500V, the diode 41 is reverse-biased by the output voltage (500V) of the DC power supply 1 and therefore does not conduct. Therefore, the magnetic energy of the flyback transformer 40 is not fed back to the DC power source 1. However, if the magnetic energy of the flyback transformer 40 is large and the voltage of the second secondary winding N3 exceeds 500V, the diode 41 is also conducted and the magnetic energy of the flyback transformer 40 is transferred only to the reverse voltage power source 4. Instead, it returns to the DC power source 1 through the second secondary winding N3.

  That is, when the voltage of the second secondary winding N3 is 500 V or less, the magnetic energy of the flyback transformer 40 is fed back only to the reverse voltage power source 4 through the first secondary winding N2, and the second When the voltage of the secondary winding N3 exceeds 500V, the magnetic energy of the flyback transformer 40 passes through the first secondary winding N2 and the second secondary winding N3 to the reverse voltage power supply 4 and the DC power supply 1. Returned to both sides. In this state, the voltage of the second secondary winding N3 is clamped to the output voltage Vm of the DC power supply 1. Since the DC power supply 1 has a considerably larger capacity than the reverse voltage power supply 4, even if the magnetic energy of the flyback transformer 40 is fed back, the output voltage Vm hardly changes and is always approximately 500V. Therefore, since the voltage of the second secondary winding N3 is clamped to 500V, the first secondary winding N2 is clamped to 100V, a voltage corresponding to the turn ratio (n2 / n3 = 5). As described above, when the voltage of the reverse voltage power supply 4 reaches 100 V due to the magnetic energy of the flyback transformer 40, the surplus magnetic energy of the flyback transformer 40 is fed back to the DC power supply 1, so that the reverse voltage power supply 4 Will not be overcharged.

  In the above example, the ratio between Vm / Vr and the turns ratio (n2 / n3) is set equal, but the ratio between Vm / Vr and the turns ratio (n2 / n3) is determined according to the overcharge range of the reverse voltage power supply 4. That's fine. For example, when the turns ratio (n2 / n3) is 0.9 (Vm / Vr), the voltage of the first secondary winding N2 is clamped to approximately 111V and does not exceed approximately 111V. When the ratio of Vm / Vr to the turns ratio (n2 / n3) is 0.8, the voltage of the first secondary winding N2 is clamped to approximately 125V, exceeding approximately 125V. There will be no. If this voltage is within the voltage range allowed for the reverse voltage power supply 4, the turns ratio (n2 / n3) may be set smaller than the value of Vm / Vr.

  Although not shown, as a modification of the vacuum apparatus 300, in FIG. 4, the first secondary winding N2 is removed, and the magnetic energy of the flyback transformer 40 is transferred only to the DC power source 1 through the second secondary winding N3. You may return. In this case, since the magnetic energy of the flyback transformer 40 is not fed back to the reverse voltage power supply 4, it does not contribute to downsizing of the reverse voltage power supply 1, but the power loss is reduced in the same manner as the vacuum devices 100 to 300. .

  In each of the embodiments described above, the control circuit 6 causes the semiconductor switch element 5 to be turned on / off according to a predetermined pulse width at a predetermined frequency. Therefore, an abnormal discharge suppression method for detecting the occurrence of abnormal discharge and turning on the semiconductor switch element 5 by a predetermined pulse width only when the abnormal discharge is detected has already been proposed. Obviously, the suppression method can be applied to the present invention. Furthermore, a method for preventing the occurrence of abnormal discharge that does not cause abnormal discharge has been proposed by predicting the occurrence of abnormal discharge and turning on the semiconductor switch element 5 by a predetermined pulse width immediately before the occurrence of abnormal discharge. Such an abnormal discharge generation preventing method can also be applied to the present invention.

  In the above embodiment, the semiconductor switch element 5 is described as a single semiconductor element. However, since the sputtering apparatus has a load voltage of several hundred volts, when the IGBT or MOSFET is used as the semiconductor switch element 5, For example, it can be realized by one semiconductor element having a withstand voltage of 1200 V, but in the case of an electron beam apparatus, since the load voltage is about 10 kV, it can be realized by connecting a plurality of IGBTs or MOSFETs having a withstand voltage of 1200 V in series. . In this case, capacitors for equal voltage sharing are often connected in parallel to the respective IGBTs or MOSFETs, but when the IGBTs or MOSFETs are turned on, the energy charged in these capacitors is used as the primary of the flyback transformer. What is necessary is just to comprise so that it may discharge through a coil | winding.

It is a figure which shows the circuit structure of the 1st vacuum apparatus 100 which concerns on Embodiment 1 of this invention. It is a wave form diagram for demonstrating the 1st vacuum apparatus 100 which concerns on this invention. It is a figure which shows the circuit structure of the 2nd vacuum apparatus 200 which concerns on Embodiment 2 of this invention. It is a figure which shows the circuit structure of the 3rd vacuum apparatus 300 which concerns on Embodiment 3 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... DC power supply 2 ... Vacuum load 3 ... Main inductor 4 ... Reverse voltage power supply 4A ... Capacitor 4B ... Charging circuit 4C ... Diode 5 ... Semiconductor switch element 6. ..Control circuit 7 ... Capacitor 8 ... Diode 9 ... Inductance element 10 ... Diode 11 ... Reverse charge prevention diode 30 ... Flyback transformer 31 ... Diode 40 ... Flyback transformer 41 ... diode S1 ... first circuit S2 ... second circuit

Claims (9)

A main inductor connected in series between the DC power source and the vacuum load, a semiconductor switch element and a reverse voltage power source connected in parallel across the vacuum load and connected in series with each other, and the semiconductor switch element A vacuum circuit that applies a voltage having a polarity opposite to the output voltage of the DC power source from the reverse voltage power source to the vacuum load when the semiconductor switch element is on.
A capacitor that absorbs the first magnetic energy stored in the main inductor during the on period of the semiconductor switch element to store charges when the semiconductor switch element is off; and the first magnetic energy is stored in the capacitor. One end of a first circuit connected in series with a first diode that flows when absorbed is between the DC power source and the main inductor, and the other end is the main inductor and the vacuum load. And the first circuit is connected in parallel to the main inductor,
An inductance element that stores the electric charge discharged from the capacitor as the second magnetic energy when the semiconductor switch element is on, and the semiconductor switch element that has the second magnetic energy stored in the inductance element off A second circuit in which a second diode fed back to the reverse voltage power source and the DC power source is connected in series, the connection side of the capacitor and the first diode, the semiconductor switch element, A vacuum apparatus connected between a connection side to a reverse voltage power source. A main inductor connected in series between the DC power source and the vacuum load, a semiconductor switch element and a reverse voltage power source connected in parallel across the vacuum load and connected in series with each other, and the semiconductor switch element A vacuum circuit that applies a voltage having a polarity opposite to the output voltage of the DC power source from the reverse voltage power source to the vacuum load when the semiconductor switch element is on.
A capacitor that absorbs the first magnetic energy stored in the main inductor during the on period of the semiconductor switch element to store charges when the semiconductor switch element is off; and the first magnetic energy is stored in the capacitor. One end of a first circuit connected in series with a first diode that flows when absorbed is between the DC power source and the main inductor, and the other end is the main inductor and the vacuum load. And the first circuit is connected in parallel to the main inductor,
A flyback transformer for storing electric charge discharged from the capacitor as the second magnetic energy when the semiconductor switch element is on; and the semiconductor switch element connected in series to a primary winding of the flyback transformer. A second diode for passing charge from the capacitor through the primary winding to the semiconductor switch element when on, and the semiconductor switch element connected in series to the secondary winding of the flyback transformer A vacuum device comprising: a second circuit having a third diode that feeds back the second magnetic energy stored in the flyback transformer to the reverse voltage power source when the switch is off. In claim 2,
The number of turns n1 and the number of turns n2 are selected so that n1 / n2 ≦ 1 when the number of turns of the primary winding of the flyback transformer is n1 and the number of turns of the secondary winding is n2. Vacuum device. In claim 2,
When the output voltage of the DC power supply is Vm, the output voltage of the reverse voltage power supply is Vr, the number of primary windings of the flyback transformer is n1, and the number of secondary windings is n2, Vm + Vr / Vr = n1 A vacuum apparatus, wherein the voltage Vm, the voltage Vr, the number of turns n1, and the number of turns n2 are selected so as to be / n2. In claim 2,
The second circuit includes another secondary winding provided in the flyback transformer, and a fourth diode connected in series to the other secondary winding, and the semiconductor switch element A vacuum apparatus, wherein the magnetic energy stored in the flyback transformer is fed back to the DC power source via the another secondary winding and the fourth diode when the power is turned off. In claim 5,
When the output voltage of the DC power supply is Vm, the output voltage of the reverse voltage power supply is Vr, the number of turns of the secondary winding of the flyback transformer is n2, and the number of turns of the other secondary winding is n3, n2 A vacuum apparatus, wherein the voltage Vm, the voltage Vr, the number of turns n2, and the number of turns n3 are selected so that / n3 ≦ Vm / Vr. In claim 1,
The capacitance of the capacitor is such that the capacitor of the first circuit and the inductance element of the second circuit resonate, and ¼ of the resonance period Tr is equal to or less than the on-time width of the semiconductor switch element. And an inductance of the inductance element is selected. In any one of Claims 2 thru | or 6,
The capacitance of the capacitor and the flyback transformer are such that the capacitor of the first circuit and the flyback transformer resonate, and ¼ of the resonance period Tr is equal to or less than the on-time width of the semiconductor switch element. A vacuum apparatus characterized in that an inductance of is selected. In claim 1 or claim 7 ,
Said first circuit said capacitor reverse charging prevention diode in parallel are connected, the on state of the semiconductor switching element the charge of the capacitor when the semiconductor switching element is turned on after the discharge through the inductance element In the vacuum device, the second magnetic energy stored in the inductance element is circulated through the second diode and the semiconductor switch element.

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