JP2021103919A - Power supply system - Google Patents

Abstract

To provide a power supply unit which facilitates restarting of operation of a sputtering apparatus while protecting a power supply from an overcurrent of the sputtering apparatus.SOLUTION: A power supply system 12 comprises: a power supply unit 22; a pulse current path 28 through which a pulse current of the power supply unit 22 passes; a protective device 23 provided in the pulse current path 28; and a control signal generation unit 24 which controls the protective device 23. The protective device 23 comprises: a current limiting device 30 and a switching unit 31 connected in series and provided in the pulse current path 28; and a resistance unit 36 connected in parallel to the switching unit 31. The control signal generation unit 24 turns off the switching unit 31 when current in the pulse current path 28 exceeds a first predetermined value, and then turns back on the switching unit 31 when the current in the pulse current path 28 falls below a second predetermined value (<the first predetermined value) within a predetermined time, and stops the power supply unit 22 when the current does not fall below.SELECTED DRAWING: Figure 1

Description

The present invention relates to a power supply system applied to a sputtering apparatus or the like.

As a sputtering device for forming a film, there is one that uses high power pulse sputtering such as HiPIMS (High Power Impulse Magnetron Sputtering). In such a film forming apparatus, a protective device that protects the power supply device from an overcurrent caused by a sudden arc discharge or the like is required.

Patent Document 1 discloses a power supply system applied to a sputtering apparatus. In this power supply system, paying attention to the fact that when an arc discharge occurs in a vacuum chamber that generates pulse sputtering, the voltage across the sputtering device drops, the voltage across the sputtering device is detected, and the voltage across the sputtering device drops below the threshold. Then, the power supply from the power supply system to the sputtering device is cut off.

Patent Document 2 discloses a power supply system that is applied to a sputtering device that forms a film by HiPIMS and protects the power supply device from overcurrent. In the power supply system, a switch is provided in the pulse current path, and when the current in the pulse current path exceeds a predetermined threshold value, the switch is switched from the closed position to the open position. Then, the overcurrent flows to the resistance portion having a large resistance value connected in parallel with the switch, so that the overcurrent drops to a predetermined value or less.

Japanese Unexamined Patent Publication No. 2004-7885 Japanese Patent No. 6348243

In the conventional sputtering apparatus, when an overcurrent occurs, the power supply unit is stopped in order to extinguish the arc discharge. Then, after that, the power supply unit and the sputtering apparatus are restarted to restart the sputtering of the sputtering apparatus. A predetermined procedure is required for restarting the power supply unit and restarting the operation of the sputtering device, which takes time and effort.

On the other hand, there are many arc discharges of a sputtering device that spontaneously disappear in a short time.

The present inventors have dealt with the arc discharge that disappears in a short time of such a sputtering apparatus, and have come up with the following first idea. As a first step, even if an overcurrent occurs, the operation of the power supply unit is not immediately stopped, the pulse current path is opened, and instead, the current is supplied to the sputtering apparatus through a resistor having a large resistance value. As a result, the power supply unit can be protected from overcurrent. As a second step, if the overcurrent has disappeared after a predetermined time, the pulse current path is closed and the sputtering apparatus is restarted promptly. As a result, it is possible to save the trouble and time of restarting the power supply unit and the sputtering device for the arc discharge that disappears in a short time.

On the other hand, there is a delay time from the detection of the overcurrent of the pulse current path to the opening of the pulse current path by the switching unit. Since the current in the pulse current path due to the arc discharge rises at once in a short time, the current value in the pulse current path may exceed the rated upper limit within the delay time. Further, if the discharge current value of the vacuum chamber of the sputtering apparatus is large, it is expected that the discharge state of the vacuum chamber will change and the arc discharge will be prolonged.

The power supply systems of Patent Documents 1 and 2 cannot reduce the labor and time for restarting the sputtering apparatus while protecting the power supply unit from overcurrent.

An object of the present invention is to provide a power supply system that saves time and effort for restarting a sputtering apparatus while protecting the power supply unit from overcurrent.

The power supply system of the present invention
A power supply system that supplies pulsed current to a sputtering device.
The power supply unit that generates pulse current and
A protective device that controls the pulse current path through which the pulse current passes from the power supply unit to the sputtering device based on a control signal.
A control signal generation unit that generates the control signal to be output to the protection device,
With
The protective device is
A detector that detects the current in the pulse current path and
A switching unit that opens and closes the pulse current path,
A resistor section connected in parallel to the switching section and
A current limiting device connected in series with the switching unit and deployed in the pulse current path,
With
The control signal generation unit
When the detected current as the current of the pulse current path detected by the detector becomes the first predetermined value or more, the switching unit opens the pulse current path and opens the pulse current path.
When the detected current becomes equal to or less than the second predetermined value smaller than the first predetermined value within a predetermined time after becoming equal to or more than the first predetermined value, the switching unit outputs a control signal for closing the pulse current path to the protection device. And
When the detected current does not fall below the second predetermined value within the predetermined time, the power supply unit is stopped.

According to the present invention, the current limiting device suppresses the current rise in the pulse current path due to the occurrence of an abnormality such as an arc discharge in the sputtering device. As a result, even if there is a delay time before the switching unit of the pulse current path protection device opens the pulse current path, a current exceeding the upper limit of the rating flows to the power supply unit through the pulse current path during the delay time. It is possible to protect the power supply unit from overcurrent.

On the other hand, since the current limiting device suppresses the energizing current of the sputtering device during the delay time, it prevents the discharge state of the sputtering device from changing significantly from that in the normal state. In this way, the possibility that the overcurrent is naturally settled within a predetermined time can be increased, and the labor and time for restarting the sputtering apparatus can be shortened.

Preferably, in the present invention
The current limiting device has one or more current limiting devices and has one or more current limiting devices.
Each current limiter
An annular iron core whose circumferential direction is divided by a plate-shaped gap,
A winding portion wound around the annular iron core to form a part of the pulse current path, and a winding portion.
A plate-shaped permanent magnet arranged in the plate-shaped gap of the annular core so as to generate a second magnetic flux in the direction opposite to the first magnetic flux generated by the pulse current in the annular core.
To be equipped.

According to this configuration, as the current limiting device, a current limiting device in which a plate-shaped permanent magnet is arranged in a plate-shaped gap of an annular iron core is used. As a result, the current limiting device can be miniaturized.

Preferably, in the present invention
The annular core includes a first core portion around which the winding portion is wound and two second core portions that are coupled to both ends of the first core portion and have a plate-shaped permanent magnet arranged between them. Including
The annular core is thinner in the first core portion than in the second core portion.

According to this configuration, the first core portion around which the winding portion is wound is made thinner than the two second core portions in which the plate-shaped permanent magnet is arranged between them. As a result, the increase of the first magnetic flux when an abnormal current is generated is suppressed, and the demagnetization of the plate-shaped permanent magnet is suppressed.

Preferably, in the present invention, the plate-shaped permanent magnet has a dimension in the plate surface direction smaller than the plate-shaped gap.

According to this configuration, the plate-shaped permanent magnet has a dimension in the plate surface direction smaller than that of the plate-shaped gap. As a result, the first magnetic flux generated by the winding portion when an overcurrent is generated passes away from the plate-shaped permanent magnet in the plate-shaped gap, so that demagnetization of the plate-shaped permanent magnet is suppressed.

Preferably, in the present invention
The power supply unit generates both positive and negative pulse currents, and the power supply unit generates both positive and negative pulse currents.
The current limiting device is
A first half-wave rectifier circuit that allows only positive pulse current to pass, a second half-wave rectifier circuit that allows only negative pulse current to pass, and a first current limiter connected in series with the first half-wave rectifier circuit. When,
A second current limiter connected in series with the second half-wave rectifier circuit,
To be equipped.

According to this configuration, the current limiting device can deal with the case where the power supply unit generates pulse currents in both positive and negative directions.

Preferably, in the present invention
The power supply unit generates both positive and negative pulse currents, and the power supply unit generates both positive and negative pulse currents.
The current limiting device is
A full-wave rectifier circuit provided in the pulse current path and
With the third current limiter connected to the full-wave rectifier circuit so that the current flowing through the winding portion generates the first magnetic flux in the direction opposite to the second magnetic flux for both positive and negative pulse currents. ,
To be equipped.

According to this configuration, the current limiting device can deal with the case where the power supply unit generates pulse currents in both positive and negative directions.

Preferably, in the present invention, the current limiting device includes a plurality of current limiting devices in which winding portions are connected in series.

According to this configuration, since the generated voltage of the power supply unit is divided into a plurality of current limiters connected in series, it can be applied to the power supply unit having a large generated voltage.

Preferably, in the present invention, the current limiting device includes a plurality of current limiting devices in which winding portions are connected in parallel.

According to this configuration, the generated current of the power supply unit is divided into a plurality of current limiters connected in parallel, so that it can be applied to the power supply unit having a large generated current.

It is a block diagram of a sputtering system. It is a detailed view of a power-source part. It is a figure which shows the structure of the current limiting device together with the typical electric wiring. It is a perspective view of the current limiter of FIG. It is a graph of the magnetic characteristics of a current limiter. It is a measurement graph which investigated the current limiting performance of a current limiting device by simulation and experiment. It is a flowchart of the control method of a power-source part and a protection device by a control signal generation part. It shows various forms of current limiting devices. It is a block diagram of the current limiting device which coped with the bidirectional sputter pulse of a power-source part using a half-wave rectifier circuit. It is a block diagram of the current limiting device which coped with the bidirectional sputter pulse of a power-source part using a full-wave rectifier circuit. It is a block diagram of the current limiting device which can cope with a large overvoltage. It is a block diagram of the current limiting device which can cope with a large overcurrent.

Hereinafter, preferred embodiments of the present invention will be described in detail. In addition. It goes without saying that the embodiments do not limit the present invention to the embodiments. Further, in the embodiment, a common reference code is used for substantially the same or equivalent elements and parts. A plurality of elements having the same structure use a code having the same number but different subscripts.

(Sputtering system)
FIG. 1 is a block diagram of the sputtering system 10. The sputtering system 10 includes a sputtering device 11 and a power supply system 12 that supplies a pulse current for sputtering to the sputtering device 11.

The sputtering apparatus 11 includes a vacuum chamber 16. The target electrode 17 and the substrate 18 are arranged in the vacuum chamber 16. The target electrode 17 constitutes a negative electrode, and the substrate 18 constitutes a positive electrode. The normal discharge of sputtering of the sputtering apparatus 11 is a glow discharge, but occasionally an arc discharge Da, which is an abnormal discharge, occurs. Since the arc discharge Da becomes an overcurrent in the power supply system 12 and may damage both the sputtering apparatus 11 and the power supply system 12, it is necessary to prevent the arc discharge Da from occurring.

The power supply system 12 includes a power supply unit 22 that generates a pulse current, a pulse current path 28 that is provided on the output side of the power supply unit 22 and passes through when the pulse current from the power supply unit 22 is supplied to the sputtering device 11. It includes a protection device 23 provided in the middle of the pulse current path 28, and a control signal generation unit 24 that outputs a control signal to the protection device 23 to control the protection device 23.

The power supply unit 22 is of a bipolar pulse (both positive and negative pulses) system. The power supply unit 22 also has a monopolar pulse system.

The protection device 23 further includes a current limiting device 30, a switching unit 31, and a shunt resistor 32. The current limiting device 30, the switching unit 31, and the shunt resistor 32 are arranged in series in the pulse current path 28. The bypass path 35 is connected to both ends of the switching unit 31 at both ends. The resistance portion 36 has a large resistance value and is provided on the bypass path 35. The switching unit 31 and the resistance unit 36 are in a parallel connection relationship.

The switching unit 31 has semiconductor switches 39a and 39b connected in series to each other and diodes 40a and 40b connected in parallel to the semiconductor switches 39a and 39b, respectively. The semiconductor switches 39a and 39b are switched between on (closed position) and off (open position) according to the gate signal (control signal) from the control signal generation unit 24. The semiconductor switches 39a and 39b are always kept on. When the semiconductor switch 39a is turned off, the positive current is prevented from flowing from the power supply unit 22 toward the vacuum chamber 16 in the pulse current path 28. When the semiconductor switch 39b is turned off, negative current is prevented from flowing from the power supply unit 22 toward the vacuum chamber 16 in the pulse current path 28.

In FIG. 1, the sputtering current Is is a current corresponding to the pulse currents Sa and Sb described later in FIG. The current It includes all currents flowing through the pulsed current path 28. The sputtering current Is is included in the current It. The arrows of the sputtering current Is and the current It in FIG. 1 are aligned with the directions of the currents that apply a negative pulse to the target electrode 17 as the negative electrode of the sputtering apparatus 11 for convenience of explanation.

(Power supply part)
FIG. 2 is a detailed view of the power supply unit 22. The power supply unit 22 includes a three-phase AC power supply 43, an AC / DC converter 44, a primary side pulse generation unit 45, a transformer unit 46, and a secondary side pulse generation unit 47. The secondary side pulse generation unit 47 includes an LC circuit 48.

The three-phase AC output from the three-phase AC power supply 43 is converted into a DC voltage by the AC / DC converter 44. The primary side pulse generation unit 45 converts the DC voltage from the AC / DC converter 44 into a voltage to generate pulse currents Pa and Pb, which are supplied to the primary side of the transformer unit 46. The transformer unit 46 generates secondary side pulse currents Sa and Sb from the pulse currents Pa and Pb and supplies them to the secondary side pulse generation unit 47. The secondary side pulse generation unit 47 includes an LC circuit 48, and the pulse currents Sa and Sb are output to the power supply system 12 via the LC circuit 48.

(Current limiter)
FIG. 3 is a diagram showing the configuration of the current limiting device 30 together with the schematic electrical wiring. FIG. 4 is a perspective view of the current limiter 53 of FIG. The current limiting device 30 includes one or more current limiting devices 53. The example of FIG. 3 is an example in which the current limiting device 30 includes a single current limiting device 53.

The current limiter 53 includes an annular iron core 56 and a plate-shaped permanent magnet 57. The annular iron core 56 is divided by a plate-shaped gap 58 at one location in the circumferential direction. As a result, the divided cross section 59 is a surface formed on the annular iron core 56 by being divided by the plate-shaped gap 58, and faces each other with the plate-shaped gap 58 in between.

Both sides of the plate-shaped permanent magnet 57 have north and south poles, respectively. The plate-shaped permanent magnet 57 is arranged in the plate-shaped gap 58 with both sides in close contact with the partial cross section 59.

The size of the plate-shaped permanent magnet 57 in the plate surface direction is set to be smaller than that of the plate-shaped gap 58. Therefore, between the pair of partial cross sections 59, a portion occupied by the plate-shaped permanent magnet 57 in the plane direction of the partial cross section 59 and a portion left as a gap 60 without occupying the partial cross section 59 are composed.

The annular core 56 includes a U-shaped portion 64 as a first core portion and block portions 65 and 66 as a pair of second core portions of a rectangular parallelepiped connected to the end faces of the legs of the U-shaped portion 64 on the side surface. .. The cross section of the magnetic path in the annular iron core 56 is narrower in the U-shaped portion 64 than in the block portions 65 and 66. The winding portion 68 forms a part of the pulse current path 28 and is wound around the U-shaped portion 64.

The winding unit 68, the power supply unit 69, and the load 70 form a loop circuit. The load 70 corresponds to the sputtering apparatus 11.

The sputtering current Is of the winding portion 68 generates a first magnetic flux Fa in the annular iron core 56. The plate-shaped permanent magnet 57 generates a second magnetic flux Fb in the annular iron core 56. The first magnetic flux Fa and the second magnetic flux Fb are opposite to each other. The second magnetic flux Fb is a fixed value, and the first magnetic flux Fa changes according to an increase or decrease in the current It.

(Dimensional example of current limiter)
Taking FIG. 3 as a front view of the current limiting device 30, exemplifying the vertical, horizontal, and depth dimensions of the front view, the dimensions are approximately as follows. The unit is mm.
Vertical of current limiter 53: 33
Next to the current limiter 53: 30
Depth of current limiter 53: 10
Thickness of plate gap 58: 1
Number of turns of winding part 68: 3 turns Diameter of winding part 68: 3.5φ

(Magnetic characteristics of current limiter)
FIG. 5 is a graph of the magnetic characteristics of the current limiter 53. The horizontal axis is the magnetomotive force M, and the vertical axis is the magnetic flux F.

The magnetomotive force M has a proportional relationship with the current It flowing through the winding portion 68. M1 to M4 correspond to I1 to I4. I1 corresponds to the current It = 0A (0 amperes). The magnetomotive force ranges Ma and Mb correspond to the current ranges Ia and Ib, respectively.

Id1 is a current value that the control signal generation unit 24 determines that an overcurrent has occurred in the pulse current path 28 from the voltage across the shunt resistor 32. Id2 is set as an intermediate value between I2 and Id1. Id1 and Id2 will be described later in FIG.

When the current It = 0A, the magnetic flux of the current limiter 53 is −Fb. In FIG. 5, the direction of the first magnetic flux Fa is positive. Since the sputtering current Is changes in the range Ia, the magnetomotive force M changes in the range Ma when the sputtering apparatus 11 is operating normally. Since the inductance in the range magnetomotive force M is almost 0, the power loss due to the sputtering current Is can be ignored.

When the arc discharge of the sputtering apparatus 11 occurs, the current It increases. That is, it rapidly moves in the positive direction of the horizontal axis. When the current It reaches Id1, the control signal generation unit 24 starts an operation of switching the switching unit 31 from on to off.

A delay time Td occurs from the detection time to the operation time. The detection time is the time when the current It = Id1 is reached, and corresponds to the time t3 in FIG. The operation time is the time when the switching unit 31 is actually turned off, and corresponds to the time t4 in FIG.

Therefore, by the time the switching unit 31 is switched off, the current It continues to rise and enters the range Ib. In the range Ib, the inductance of the current limiter 53 is large, so that the rate of increase of the current It decreases.

In this way, at the operating time, the switching unit 31 switches to the open position while keeping the current It ≦ Ie. Ie is defined as the rated upper limit current of the power supply unit 22. As a result, the power supply unit 22 is protected from overcurrent.

After the operation time, the current It flows through the resistance portion 36 having a large resistance value. As a result, the current It is sufficiently lower than the value at the operating time. Then, in the vacuum chamber 16 of the sputtering apparatus 11, the arc discharge Da is calmed down.

On the other hand, by maintaining the current It ≦ Ie during the delay time Td, it is possible to prevent the state of the vacuum chamber 16 from becoming abnormal. Therefore, during the period of the delay time Td, it is suppressed that the discharge state of the vacuum chamber 16 of the sputtering apparatus 11 changes in the direction of prolonging the arc discharge as compared with the discharge state at the time of normal glow discharge. As a result, there is an increased possibility that the arc discharge Da will be within the predetermined time T1 (see step 106 in FIG. 7). In this way, without stopping the operation of the power supply unit 22, after the elapse of the predetermined time T1, the supply of the pulse current of the sputtering device 11 is promptly restarted, and the power supply unit 22 and the sputtering device 11 are restarted (restarted). ) Can be omitted.

(Action)
FIG. 6 is a measurement graph in which the current limiting performance of the current limiting device 53 is examined by simulation and experiment. The top is the simulation measurement graph, and the bottom is the experimental measurement graph. In the measurement graph of the simulation, the characteristics of the power supply unit with a current limiter (solid line) and the characteristics of the power supply unit with only a reactor without a current limiter (broken line) are compared. The reactor without the current limiter 53 means that the protective device 23 is removed from the power supply system 12. The reactor itself refers to, for example, the coil of the LC circuit 48 of FIG.

At time t1 (15 μs on the horizontal axis), an arc discharge Da is generated in the vacuum chamber 16 of the sputtering apparatus 11. As a result, the current It starts to rise.

In the simulation measurement graph, at time t2, in the experimental measurement graph, at time t3, the current It = Id1 (see FIG. 5). In FIG. 6, for example, Id1 = 120A is set.

The control signal generation unit 24 detects that the current It has reached Id1 from the voltage across the shunt resistor 32. For convenience of explanation, t2 and t3 will be referred to as "detection time".

As described above, since the delay time Td exists, it takes time for the semiconductor switch 39 to actually open the bypass path 35, and the current It continues to increase even after the times t2 and t3.

The protection device 23 as an actual machine receives the control signal from the control signal generation unit 24, and the bypass path 35 is opened at time t4. The measured value of the delay time Td of the actual machine was 22 μs. At that time, the current was measured as It = 220A.

When the delay time Td = 22 μs is applied to the measurement graph of the simulation, the time from the time t2 to the time after the delay time Td is t5. Since the time t5 is the time when the switching unit 31 is actually switched off, it will be referred to as the “operating time” for convenience of explanation.

The current It = 220A is the current It ≦ Ie (Ie is the rated upper limit current of the power supply unit 22), and the sputtering system 10 can protect the power supply unit 22 in spite of the existence of the delay time Td. I found that I could do it.

(Control signal generator)
FIG. 7 is a flowchart of a control method of the power supply unit 22 and the protection device 23 by the control signal generation unit 24. The control signal generation unit 24 controls the operation and stop of the power supply unit 22 together with the protection device 23.

In step S100, the control signal generation unit 24 detects the current It from the voltage across the shunt resistor 32.

In step S102, the control signal generation unit 24 determines whether or not the current It ≧ Id1. Then, when the determination result is positive, the process proceeds to step S104, and when the determination result is negative, the process ends.

In step S104, the control signal generation unit 24 switches the switching unit 31 from on to off. However, the switching unit 31 is actually turned off after the delay time Td is delayed from the execution time of STEP104. The execution time corresponds to the above-mentioned detection time, and corresponds to, for example, the time t3 in FIG.

In step S106, the control signal generation unit 24 starts measuring the elapsed time Tc by the timer (not shown).

In step S108, the control signal generation unit 24 determines whether or not the elapsed time Tc is T1 or more. Then, as soon as the determination result becomes positive, the process proceeds to step S110.

In step S110, the control signal generation unit 24 detects the current It as in step S100.

In step S112, the control signal generation unit 24 determines whether or not the current It ≦ Id2 (see FIG. 5). In addition, I2 <Id2 <Id1.

When the determination result in step S112 is affirmative, the control signal generation unit 24 advances the process to step S114, and when it is negative, the control signal generation unit advances the process to step S116.

If the determination result in step S112 is affirmative, it means that the arc discharge Da in the vacuum chamber 16 has naturally disappeared. The fact that the determination result in step S112 is negative means that there is a high possibility that the arc discharge Da in the vacuum chamber 16 is still continuing, or even if the switching unit 31 is switched from off to on, the arc is immediately performed. This means that there is a high possibility that an electric discharge Da will occur.

In step S114, the control signal generation unit 24 switches the switching unit 31 from off to on. As a result, the supply of the sputtering current Is from the power supply system 12 to the target electrode 17 of the sputtering apparatus 11 is restarted. After this, the control signal generation unit 24 ends the process.

In step S116, the control signal generation unit 24 stops the power supply unit 22. After this, the control signal generation unit 24 ends the process.

An operator (also an operator of the sputtering system 10) notifies that the control signal generation unit 24 executes step S116 and the power supply unit 22 is stopped by a predetermined notification device (eg, display, notification lamp, or notification). Informed by the speaker). In that case, if the operator examines the situation of the sputtering device 11 and determines that there is no problem even if the operation of the sputtering device 11 is restarted, the power supply unit 22 is started and the sputtering device 11 is operated after the start-up. Resume according to the prescribed procedure. The work of starting and restarting these operations takes time and effort.

(Various forms of current limiter)
FIG. 8 shows various forms of the current limiter 53. For the U-shaped portion 64, any one of three types of a stacked iron core, a wound iron core, and a powder molded iron core can be adopted. On the other hand, a stacked iron core or a powder molded iron core can be adopted for the block portions 65 and 66.

In the current limiter 53a, the U-shaped portion 64a, the block portion 65a, and the block portion 66a are all iron stacking cores.

In the current limiter 53b, the U-shaped portion 64b is a wound iron core, and the block portion 65a and the block portion 66a are stacked iron cores.

In the current limiter 53c, the U-shaped portion 64a, the block portion 65a, and the block portion 66a are all powder molded iron cores.

In the current limiter 53d, the U-shaped portion 64c is a wound iron core, and the block portion 65a and the block portion 66a are powder molded iron cores.

(Bidirectional current limiting device)
FIG. 9A is a configuration diagram of a current limiting device 30u that copes with bidirectional sputter pulses (sputter current Is) of the power supply unit 69 by using a half-wave rectifier circuit. In FIG. 9A and FIG. 9B below, the directions of Is and It shown are aligned with the directions when the output pulse of the power supply unit 69 is positive. When the output pulse of the power supply unit 69 is negative, the directions of Is and It are opposite to those shown in the drawing.

In the current limiting device 30u, the diodes 75u and 75v are connected in parallel to each other between the power supply unit 69 and the load 70 so as to form a half-wave rectifier circuit in which the opposite directions are forward. The current limiting devices 53u and 53v are connected in series with the diodes 75u and 75v, respectively.

The diode 75v corresponds to a first half-wave rectifier circuit that allows only a positive pulse current to pass. The diode 75u corresponds to a second half-wave rectifier circuit that allows only a negative pulse current to pass. The current limiter 53v constitutes a first current limiter connected in series with the first half-wave rectifier circuit. The current limiter 53u corresponds to a second current limiter connected in series with the second half-wave rectifier circuit.

FIG. 9B is a configuration diagram of a current limiting device 30w in which a bidirectional sputter pulse (sputter current Is) of the power supply unit 69 is dealt with by using a full-wave rectifier circuit. The diodes 78a to 78d form a full-wave rectifier circuit provided in the pulse current path 28. The current limiter 53w is connected to a full-wave rectifier circuit so that the current flowing through the winding portion 68w generates the first magnetic flux Fa in the direction opposite to the second magnetic flux Fb for both positive and negative pulse currents. Consists of 3 current limiters.

(Another form of current limiting device)
FIG. 10A is a configuration diagram of a current limiting device 30p capable of coping with a large overvoltage. In the current limiting device 30p, a plurality of (eg, two) current limiting devices 53 are connected in series. In the current limiting device 30p, the voltage across the current limiter 53 is divided into the current limiting devices 53. As a result, the overvoltage that the current limiting device 30 can handle increases.

FIG. 10B is a configuration diagram of a current limiting device 30q capable of coping with a large overcurrent. In the current limiting device 30q, a plurality of (eg, two) current limiting devices 53 are connected in parallel. In the current limiting device 30q, the overcurrent is diverted to each current limiting device 53, so that the overcurrent that can be dealt with by the current limiting device 30p as a whole can be increased.

(Modification example)
In the power supply system 12 of the embodiment, since the power supply unit 22 is a bipolar pulse generation method, the switching unit 31 deals with pulses in both positive and negative directions. Semiconductor switches 39a and 39b are provided. When the power supply unit 22 is of the monopolar pulse generation method, one of the semiconductor switches 39a and 39b and both the diodes 40a and 40b can be omitted.

The current limiter 53 of the embodiment includes a plate-shaped permanent magnet 57 as a current limiter. When the power supply unit of the present invention detects an overcurrent, the operation of the power supply unit 22 is not stopped immediately, but only restarts the operation of the sputtering device after a predetermined time. A flow device (eg, an electromagnet type current limiter) can also be provided.

In the embodiment, a shunt resistor 32 is provided as a detector for detecting the current It of the pulse current path 28. In the present invention, a CT (Current Transformer) can be used as a detector in addition to the shunt resistor 32.

11 ... Spattering device, 12 ... Power supply system, 22 ... Power supply unit, 23 ... Protective device, 24 ... Control signal generator, 28 ... Pulse current path, 30 ... Limited Flow device, 31 ... switching part, 32 ... shunt resistance, 35 ... bypass path, 36 ... resistance part, 39 ... semiconductor switch, 40 ... diode, 53 ... current limiting Vessel, 56 ... annular iron core, 57 ... plate-shaped permanent magnet, 58 ... plate-shaped gap, 59 ... divided section, 60 ... void, 68 ... winding part.

Claims (8)

A power supply system that supplies pulsed current to a sputtering device.
The power supply unit that generates pulse current and
A protective device that controls the pulse current path through which the pulse current passes from the power supply unit to the sputtering device based on a control signal.
A control signal generation unit that generates the control signal to be output to the protection device,
With
The protective device is
A detector that detects the current in the pulse current path and
A switching unit that opens and closes the pulse current path,
A resistor section connected in parallel to the switching section and
A current limiting device connected in series with the switching unit and deployed in the pulse current path,
With
The control signal generation unit
When the detected current as the current of the pulse current path detected by the detector becomes the first predetermined value or more, the switching unit opens the pulse current path and opens the pulse current path.
When the detected current becomes equal to or less than the second predetermined value smaller than the first predetermined value within a predetermined time after becoming equal to or more than the first predetermined value, the switching unit outputs a control signal for closing the pulse current path to the protection device. And
A power supply system characterized in that the power supply unit is stopped when the detected current does not fall below the second predetermined value within the predetermined time. In the power supply system according to claim 1,
The current limiting device has one or more current limiting devices and has one or more current limiting devices.
Each current limiter
An annular iron core whose circumferential direction is divided by a plate-shaped gap,
A winding portion wound around the annular iron core to form a part of the pulse current path, and a winding portion.
A plate-shaped permanent magnet arranged in the plate-shaped gap of the annular core so as to generate a second magnetic flux in the direction opposite to the first magnetic flux generated by the pulse current in the annular core.
A power supply system characterized by being equipped with. In the power supply system according to claim 2,
The annular core includes a first core portion around which the winding portion is wound and two second core portions that are coupled to both ends of the first core portion and have a plate-shaped permanent magnet arranged between them. Including
A power supply system characterized in that the annular core is thinner than the second core portion in the first core portion. In the power supply system according to claim 2 or 3.
The plate-shaped permanent magnet is a power supply system characterized in that the dimension in the plate surface direction is smaller than the plate-shaped gap. In the power supply system according to any one of claims 2 to 4.
The power supply unit generates both positive and negative pulse currents, and the power supply unit generates both positive and negative pulse currents.
The current limiting device is
A first half-wave rectifier circuit that allows only positive pulse current to pass, a second half-wave rectifier circuit that allows only negative pulse current to pass, and a first current limiter connected in series with the first half-wave rectifier circuit. When,
A second current limiter connected in series with the second half-wave rectifier circuit,
A power supply system characterized by being equipped with. In the power supply system according to any one of claims 2 to 5.
The power supply unit generates both positive and negative pulse currents, and the power supply unit generates both positive and negative pulse currents.
The current limiting device is
A full-wave rectifier circuit provided in the pulse current path and
With the third current limiter connected to the full-wave rectifier circuit so that the current flowing through the winding portion generates the first magnetic flux in the direction opposite to the second magnetic flux for both positive and negative pulse currents. ,
A power supply system characterized by being equipped with. In the power supply system according to any one of claims 2 to 6.
The current limiting device is a power supply system including a plurality of current limiting devices in which winding portions are connected in series. In the power supply system according to any one of claims 2 to 6.
The current limiting device is a power supply system including a plurality of current limiting devices in which winding portions are connected in parallel.

Images