JP4393158B2 - Power supply for sputtering - Google Patents

Description

  The present invention relates to a power source for sputtering used in the manufacture of semiconductors such as transistors and ICs and other electronic components.

  A conventional example is shown in FIG. The sputtering power supply according to this conventional example includes a filter circuit having a choke Lo and a smoothing capacitor Co on the output side. In series with the output of the filter circuit, an auxiliary choke Lr for suppressing abnormal discharge occurring in the load 1 is connected.

A semiconductor switch SW is connected in parallel with the load 1. The semiconductor switch SW is turned on by the change of the output voltage, and the turn-off is uniquely determined by the voltage and time product of the pulse transformer that drives the semiconductor switch SW (for example, Patent Document 1).
International Publication No. 99/47727 Pamphlet

  However, the current system is a self-excited type in which the semiconductor switch is turned on due to a change in the output voltage, and the turn-off is uniquely determined by the voltage and time product of the pulse transformer that drives the semiconductor switch. When the master / slave is turned on individually due to variations in circuit turn-on conditions, the abnormal discharge suppression circuit becomes unstable.

  Further, since the semiconductor switch is self-excited by turning on the output voltage, malfunction is likely to occur. Furthermore, since the on-time is determined by the voltage and time product of the pulse transformer, it is difficult to ensure an optimum on-time.

  The present invention has been made in view of the above problems, and provides a novel sputtering power source capable of stable operation even in master-slave operation.

  In order to solve the above problems, a sputtering power source according to the present invention includes a converter, and a sputtering power source having a filter circuit having a choke and a smoothing capacitor connected to the output side of the converter. When the abnormal discharge is detected, the semiconductor switch is turned on instantaneously, the converter is stopped, the abnormal discharge energy flowing out to the load side is suppressed, the load current is detected, and this load current is detected. When it is detected that the voltage is below the standard, it is recognized as a return, and after the arbitrarily set time has elapsed, the semiconductor switch is turned off and the converter is also started to operate so that the discharge can be sustained quickly. The abnormal discharge suppression circuit configured as described above is provided.

  An auxiliary choke for suppressing abnormal discharge generated in the load is connected in series with the output of the filter circuit.

  A diode is connected in parallel to the smoothing capacitor and connected to a connection point between the choke and the auxiliary choke.

  When the input current of the choke exceeds the reference and the output voltage becomes lower than the reference, it is determined that an abnormal discharge has been detected.

  A diode is connected between the input / output terminals of the semiconductor switch.

  When a slave machine is connected in parallel with the power supply for sputtering and when abnormal discharge is detected from this slave machine or when abnormal discharge generated by a load is detected, the semiconductor switch SW is turned on instantaneously and the converter is stopped. The abnormal discharge energy flowing out to the load side is suppressed, and the load current is detected.

  When it is detected that the load current of the converter or the load current of the slave machine has fallen below the reference current, it is recognized as a return, and after the arbitrarily set time has elapsed, the semiconductor switch is turned off and the converter is also The operation is started.

  According to the present invention, when an abnormal discharge is detected, the semiconductor switch is turned on instantaneously, the converter is stopped, the abnormal discharge energy flowing out to the load side is suppressed, the load current is detected, and this load is detected. When it is detected that the current has fallen below the standard, it is recognized as a return, and after the arbitrarily set time has elapsed, the semiconductor switch is turned off and the converter is also started to operate smoothly and normally. Can last. Thereby, there is an effect that a stable operation can be performed even in the master-slave operation. In addition, there is an effect that malfunction can be prevented even by output voltage fluctuation.

  The best mode for carrying out the power supply for sputtering according to the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows the best mode for carrying out a sputtering power source according to the present invention. C is a capacitor, SW is a semiconductor switch, D is a diode, L is a choke, 1 is a load, and 2 is a converter.

  The sputtering power source according to the present embodiment includes a converter 2, and a filter circuit having a choke Lo and a smoothing capacitor Co is connected to the output side of the converter 2. Further, a semiconductor switch SW composed of an IGBT is connected in parallel with the load 1. In series with the output of the filter circuit, an auxiliary choke Lr for suppressing abnormal discharge occurring in the load 1 is connected. One end of a diode Do is connected to a connection point between the auxiliary choke Lr and the choke Lo, and the diode Do is connected in parallel with the smoothing capacitor Co. A diode D2 is connected between the input and output terminals of the semiconductor switch SW.

  The sputtering power supply includes an abnormal discharge suppression circuit 10 which compares the input current IL of the choke Lo with the reference current and the comparator 11 that compares the output voltage Vo with the reference voltage. 12 and an AND circuit 13 connected to the output terminals of these comparators 11, and an abnormal discharge is detected when the input current IL of the choke Lo exceeds the reference and the output voltage Vo falls below the reference. Judging that it was.

  The AND circuit 13 is connected to the timer circuit 20, and the AND circuit 13 and the timer circuit 20 are connected to respective input terminals of the OR circuit 19 so that a constant time constant is provided to start the operation of the converter 2. .

A slave machine is connected in parallel with the power supply for sputtering. An OR circuit 15 connected to the output terminal of the slave unit and the AND circuit 13, the output terminal of the OR circuit 15 is connected to the drive circuit 18, and the output terminal of the drive circuit 18, the gate terminal of the semiconductor switch SW Is connected to. With such a configuration, when the abnormal discharge generated in the load 1 is detected, or when the abnormal discharge generated in the slave machine is detected, the semiconductor switch SW is turned on instantaneously.

Further, when an OR circuit 19 is connected to the output terminal of the AND circuit 13 and an OR circuit 16 is connected to the output terminal of the OR circuit and the slave unit, and abnormal discharge generated in the load 1 is detected, When the abnormal discharge generated in the machine is detected, the converter 2 is stopped instantaneously.

The abnormal discharge suppression circuit 10 is provided with a comparator 14 for detecting a load current. The comparator 14 is connected to the OR circuit 17, to connect the slave unit to the other input terminal of the OR circuit 17, the output terminal is connected to the drive circuit 18. With such a configuration, when it is detected that the load current Io has become below the reference value, it is recognized as a return, the drive circuit 18 recognizes this, and after an arbitrary time set by the timer circuit 20 has elapsed, the semiconductor switch SW Is turned off.

The sputtering power supply configured as described above operates as follows. First, the input current IL of the choke Lo is detected by the comparator 11, and when the input current IL of the choke Lo exceeds the reference, this abnormal signal is output to the AND circuit 13. The output voltage Vo is detected by the comparator 12 , and an abnormal signal is output to the AND circuit 13 when the output voltage Vo detected by the comparator 12 becomes equal to or lower than the reference voltage. In the AND circuit 13, when an abnormal signal is input from the comparator 11 and the comparator 12, the AND circuit 13 outputs an abnormal discharge signal to the OR circuit 15 and the OR circuit 16 via the timer circuit 20 and the OR circuit 19 .

  Further, when abnormal discharge is detected from the slave machine, an abnormal discharge signal is output to the OR circuit 15 and the OR circuit 16. When the OR circuit 15 receives an abnormal discharge signal from the converter 2 or the slave device, this signal is output to the drive circuit 13. In the drive circuit 13, when an abnormal discharge signal is input from the OR circuit 15, the drive circuit 13 recognizes that an abnormal discharge has occurred, transmits an ON signal to the semiconductor switch SW, and instantly turns on the semiconductor switch SW.

  Further, when the OR circuit 16 receives an abnormal discharge signal from the converter 2 or the slave device, this signal is output to the converter 2 and the slave device. In the converter 2, when an abnormal discharge signal is input from the OR circuit 16, the converter 2 is stopped and abnormal discharge energy flowing out to the load 1 side is suppressed.

In the sputtering power supply according to the present invention, a comparator 14 for detecting the load current Io is provided. When the load current Io of the choke Lo detected by the comparator 14 becomes below the reference, this current detection signal is output to the OR circuit 17. Also detects the same load current in the slave machine, the load current of the choke detected by the slave machine becomes a reference below, detects the current detection signal to the OR circuit 17. When a current detection signal is input to the OR circuit 17 from the converter 2 or the slave unit, the OR circuit outputs a signal, the drive circuit 18 recognizes it as a return signal, and transmits an OFF signal to the semiconductor switch SW. Turn off SW.

When the semiconductor switch SW is turned off, the timer function of the timer circuit 20 is canceled. When the OR circuit 19 receives a current detection signal, this signal is output to the converter 2. When the current detection signal is input from the OR circuit 19 to the converter 2, the converter 2 is started to operate, discharge is started quickly, and discharge is continued.

  FIG. 2 shows an embodiment of the power source for sputtering according to the present invention. This power source for sputtering includes a converter 2, and includes a choke Lo on each of the positive and negative sides of the output side of the converter 2, and a filter circuit having the choke Lo and a series circuit of two smoothing capacitors Co1 and Co2 is connected. is there. In addition, a series circuit of two semiconductor switches SW1 and SW2 constituted by IGBTs is connected in parallel with the load 1. In series with the output of the filter circuit, an auxiliary choke Lr for suppressing abnormal discharge generated in the load 1 is provided on each of the positive and negative sides.

  The connection part of the two smoothing capacitors Co1 and Co2 and the connection part of the two semiconductor switches SW1 and SW2 are connected, and the two semiconductor switches SW1 and SW2 are turned on and off simultaneously. A series circuit of diodes D1 and D2 and capacitors C1 and C2 is connected between the drain and source of each of the semiconductor switches SW1 and SW2, and resistors R1 and R2 are connected in parallel with the diodes D1 and D2 to form a DCR snubber circuit. The DCR snubber circuit balances the voltages when the semiconductor switches SW1 and SW2 are turned off.

  The sputtering power supply is also provided with an abnormal discharge suppression circuit 10. The configuration of this abnormal discharge suppression circuit 10 is substantially the same as the configuration of the abnormal discharge suppression circuit 10 provided in the sputtering power source showing the best mode for carrying out. Further, this embodiment is optimal when used when the output voltage is relatively high.

  The sputtering power supply configured as described above operates as follows. First, the input current IL of the choke Lo is detected by the comparator 11, and when the input current IL of the choke Lo exceeds the reference, this abnormal signal is output to the AND circuit 13. Further, the output voltage Vo is detected by the comparator 12, and when the output voltage Vo detected by the comparator 11 falls below the reference voltage, an abnormal signal is output to the AND circuit 13. In the AND circuit 13, when an abnormal signal is input from the comparator 11 and the comparator 12, the AND circuit 13 outputs an abnormal discharge signal to the OR circuit 15 and the OR circuit 16.

  Further, when abnormal discharge is detected from the slave machine, an abnormal discharge signal is output to the OR circuit 15 and the OR circuit 16. When the OR circuit 15 receives an abnormal discharge signal from the converter 2 or the slave device, this signal is output to the drive circuit 13. When an abnormal discharge signal is input from the OR circuit 15 in the drive circuit 13, the drive circuit 13 recognizes that an abnormal discharge has occurred, and sends an ON signal to the semiconductor switches SW1 and SW2, so that the semiconductor switches SW1 and SW2 are instantaneously and simultaneously transmitted. Let's turn on.

  Further, when the OR circuit 16 receives an abnormal discharge signal from the converter 2 or the slave device, this signal is output to the converter 2 and the slave device. In the converter 2, when an abnormal discharge signal is input from the OR circuit 16, the converter 2 is stopped and abnormal discharge energy flowing out to the load 1 side is suppressed.

In the sputtering power supply according to the present invention, a comparator 14 for detecting the load current Io is provided. When the load current Io of the choke Lo detected by the comparator 14 becomes below the reference, this current detection signal is output to the OR circuit 17. Similarly, the load current is detected also in the slave unit, and when the choke input current detected in the slave unit becomes equal to or lower than the reference, this OR circuit 17 detects this current detection signal. When a current detection signal is input from the converter 2 or the slave unit to the OR circuit 17, the OR circuit outputs a signal, the drive circuit 18 recognizes it as a return signal, and sends an OFF signal to the semiconductor switches SW1 and SW2. The semiconductor switches SW1 and SW2 are turned off simultaneously.

  When the semiconductor switches SW1 and SW2 are turned off and the timer circuit 20 is activated and the OR circuit 19 receives a current detection signal, this signal is output to the converter 2. When the current detection signal is input from the OR circuit 19 to the converter 2, the converter 2 is started to operate, discharge is started quickly, and discharge is continued.

  The power supply for sputtering of the present invention, when abnormal discharge is detected, turns on the semiconductor switch instantaneously, stops the converter, suppresses abnormal discharge energy flowing out to the load side, detects load current, When it is detected that the load current has fallen below the standard, it is recognized as a return, and after the arbitrarily set time has elapsed, the semiconductor switch is turned off and the converter is also started to operate smoothly and normally. The discharge can last. Thereby, stable operation can be performed even in the master-slave operation. Also, malfunction can be prevented due to output voltage fluctuation.

It is a circuit diagram of the best mode for carrying out the invention in the power supply for sputtering according to the present invention. 1 is a circuit diagram of Example 1. FIG. It is the circuit diagram which showed the prior art example.

Explanation of symbols

Lo choke Co, Co1, Co2 Smoothing capacitor Do Diode Lr Auxiliary choke SW, SW1, SW2 Semiconductor switch D2 Diode 1 Load 2 Converter 10 Abnormal discharge suppression circuit 11, 12, 14 Comparator 13 AND circuit 15, 16, 17, 19 OR Circuit 18 Drive circuit 20 Timer circuit

Claims (6)

In a sputtering power supply equipped with a converter and connected to a filter circuit having a choke and a smoothing capacitor on the output side of this converter, a semiconductor switch is connected in parallel with the load. Turns on the semiconductor switch, stops the converter, suppresses abnormal discharge energy flowing out to the load side, detects the load current, and recognizes that the load current is below the reference when returning and, after the time set arbitrarily, by performing the converter also operate start with turning off the semiconductor switch, Ri Oh comprise abnormal discharge suppression circuit configured to rapidly discharge is sustained, the sputter When a slave unit is connected in parallel with the power supply for the unit, and abnormal discharge is detected from this slave unit, or a load occurs When detecting that abnormal discharge, as well as on the semiconductor switch SW instantaneously, the converter is stopped, characterized in that said abnormal discharge energy to flow to the load side to suppress, are to detect the load current Power supply for sputtering. 2. The sputtering power supply according to claim 1, further comprising an auxiliary choke connected in series with the output of the filter circuit for suppressing abnormal discharge generated in the load. 3. The sputtering power supply according to claim 2, wherein a diode is connected to a connection point between the choke and the auxiliary choke and in parallel with the smoothing capacitor. 4. The apparatus according to claim 1, wherein when the input current of the choke exceeds a reference and the output voltage becomes lower than the reference, it is determined that an abnormal discharge is detected. Power supply for sputtering described in 1. The power supply for sputtering according to any one of claims 1 to 4, wherein a diode is connected between input and output terminals of the semiconductor switch. When it is detected that the load current of the converter or the load current of the slave machine has fallen below the reference current, it is recognized as a return, and after the arbitrarily set time has elapsed, the semiconductor switch is turned off and the converter is also 6. The sputtering power source according to claim 1, wherein the operation is started.

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