JP4492975B2 - Power supply, power supply for sputtering, and sputtering equipment - Google Patents

Description

  The present invention relates to a power supply, a power supply for sputtering, and a sputtering apparatus, and in particular, when a sudden short-circuit current such as arc discharge occurs in a state where a voltage is applied in the forward direction, the power supply for cutting off, a power supply for sputtering, and The present invention relates to a sputtering apparatus.

  In various plasma application devices, electromagnetic wave generators such as microwaves, power switching devices, and the like, sudden drop in impedance may occur on the load side during operation of the power supply. This decrease in impedance is caused by a short-circuit sudden current flowing on the load side. When such a sudden current occurs, the operation of the device is often adversely affected. Therefore, a circuit that reliably and quickly cuts off the sudden current is often required.

  Hereinafter, as a specific example of such a power source, a sputtering power source used for forming a thin film will be described as an example.

  FIG. 16 is a schematic diagram illustrating a configuration of a main part of a DC (direct current) sputtering apparatus. This sputtering apparatus has a vacuum chamber 101 and a DC power source 110 for sputtering. The anode of the power supply 110 is connected to the chamber 101 via the connection cable 120A and is set to the ground potential. On the other hand, the cathode of the power source 110 is connected to the sputtering target 104 provided inside the chamber 101 via the connection cable 120B. A substrate 100 on which a thin film is deposited is placed inside the chamber 101.

  In film formation, first, the inside of the chamber 101 is evacuated by the evacuation pump 106 and a discharge gas such as argon (Ar) is introduced from the gas supply source 107 to maintain the inside of the chamber at a predetermined discharge pressure. Then, an electric field is applied between the target 104 and the chamber 101 by the power source 110 to generate a glow discharge 108. Then, positive ions in the plasma generated in the discharge space collide with the surface of the target 104 and eject atoms of the target 104. By utilizing such a sputtering phenomenon, a thin film made of the material of the target 104 can be formed on the substrate 100.

  However, the discharge in the chamber 101 may stop during such a sputtering operation. For example, when the balance between the gas supplied from the gas supply source 107 and the exhaust speed of the pump 106 fluctuates, the discharge may stop and the plasma may disappear if the discharge condition is not satisfied. When the discharge is stopped, the sputtering current stops flowing, and the load impedance increases rapidly. Therefore, the power source 110 needs to have a structure that can flexibly cope with such a sudden increase in load impedance.

  On the other hand, arc discharge 150 may occur in the chamber 101 during the sputtering operation. Such arc discharge 150 occurs relatively near the target 104, but may occur near the substrate 100. When such an arc discharge 150 is generated, a large current flows locally, so that the load impedance of the chamber is lowered and the target 104 and the substrate 100 are damaged.

  For example, when the arc discharge 150 is generated on the target 104 side, a large current is concentrated in a minute region of the target 104, and a large amount of deposition material is instantaneously discharged from that portion. This phenomenon is referred to as “splash” and the like, and particles of the deposition material are scattered on the surface of the substrate 100, which causes damage.

  On the other hand, when the arc discharge 150 occurs on the substrate 100 side, the substrate 100 is often damaged and becomes defective.

  Therefore, there is a need for a sputtering power source having an arc interrupting function that can extinguish an arc quickly and reliably when such arc discharge occurs.

  For example, Patent Documents 1 to 3 disclose power supplies that cut off the output of forward power and extinguish arc discharge when arc discharge occurs.

  FIG. 17 is a schematic diagram showing an example of such a power source for sputtering.

  This power supply includes a power supply unit DCPF that outputs a controlled direct current, a rectifying inductor L0, a switching unit Q, and a cutoff circuit AS.

  This power source is controlled to output power according to a start signal (RUN) from a host control unit MCU such as a computer or a sequencer. Further, feedback control is performed according to the power setting signal (Pset) from the control unit MCU, and an appropriate current is output.

  At the start of sputtering, DC power is applied from the power supply unit DCPF to the target 104 and the chamber 101 with the switching unit Q open, and plasma is ignited.

  On the other hand, when arc discharge occurs during sputtering, the load impedance of the chamber decreases. Then, the shut-off circuit AS detects this as a decrease in output voltage or an increase in current, and closes the switching unit Q to short-circuit the output from the power supply unit DCPF, thereby shutting off the output to the chamber. The shut-off circuit AS closes the switching unit Q for a predetermined time, and then opens the switching unit Q again to restart the output of power to the chamber. If arc discharge is extinguished here, sputtering is resumed. On the other hand, when the arc discharge is not extinguished here, the interruption circuit AS again closes the switching unit Q and repeats the interruption operation. In this way, the switching unit Q is repeatedly opened and closed until there is no arc discharge.

During normal sputtering, long continuous arcs exceeding 2 milliseconds are often not observed. Then, according to the power source shown in FIG. 17, it is possible to almost certainly cut off normal arc discharge generated in the chamber.
Japanese Patent Laid-Open No. 10-298754 JP-A-10-298755 JP 2002-235170 A

  However, in the case of the power source illustrated in FIG. 17, if there is a delay in the time from the detection of arc discharge to the start of the shut-off operation, damage due to arc discharge in the chamber may increase.

  Further, when the forward power is turned on again after the arc interruption operation, if excessive power is supplied, the arc discharge may recur. Similarly, if the waiting time until the plasma ignition is long, the command current value at the time of ignition to the power source becomes large, and an overshoot state may occur.

  On the other hand, if the current leaks to the outside due to a “ground fault”, that is, a short circuit to ground, in the high voltage part inside the power supply, etc., if this cannot be distinguished from the normal chamber current, the short circuit current will continue to flow. There is also a problem of end.

  The present invention has been made on the basis of recognition of such problems, and its purpose is to quickly and surely stop arc discharge, prevent application of excessive power when power is turned on again, and quickly against ground faults. It is an object of the present invention to provide a power source, a sputtering power source and a sputtering apparatus that can cope with the above.

On the other hand, the power supply of the present invention is a power supply that outputs a forward DC power smoothed by the inductor to the load, based on the value obtained by dividing the measured value of the output voltage target value of the output power of the current When the target value is obtained, the current flowing through the inductor is controlled based on the measured value of the current flowing through the inductor and the target value of the current, and the absolute value of the measured value of the output voltage is below a certain value Is characterized in that an overcurrent is suppressed by executing the division by the constant value instead of the measured value of the output voltage .

According to the above configuration, it is possible to provide a power source that can quickly and surely stop arc discharge and prevent application of excessive power when power is reapplied .

  Here, the circuit further includes an integration circuit that integrates an error between a value obtained by dividing the target value of the output power by the measured value of the output voltage and the output current, and the integration circuit converts the target value of the output power to the output voltage. It can operate when the difference between the value divided by the measured value and the output current or the ratio falls within a certain range.

  Further, the target value of the voltage to be applied to the inductor is obtained based on the measured value of the current flowing through the inductor and the target value of the current, and the target value of the voltage and the voltage applied to the inductor The current flowing through the inductor can be controlled based on the measured value.

  On the other hand, the sputtering power source of the present invention is a sputtering power source that forms a thin film by sputtering a target, and includes any one of the above-mentioned power sources, and can perform the sputtering by applying the forward power to the target. It is characterized by that.

  On the other hand, a sputtering apparatus of the present invention is characterized by comprising the above-described sputtering power source and a vacuum chamber capable of accommodating the target and maintaining an atmosphere depressurized from atmospheric pressure.

According to the present invention, to stop the arc discharge quickly and reliably, the power supply also applies excessive power during power cycling can proof Gukoto, sputtering power and the sputtering apparatus is provided.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(First related technology )
First, as a first related technique of the present invention, a power supply capable of starting an arc interrupting operation very quickly when occurrence of arc discharge is detected will be described.

FIG. 1 is a schematic diagram illustrating a main part of a power supply according to the related technology .

FIG. 2 is a schematic diagram showing a main part of a power source of a comparative example that the inventor made in the process of reaching the related technology .

  Hereinafter, the power source of the comparative example shown in FIG. 2 will be described first.

  This power supply has two inverter outputs sharing the DC power supply DC1 and the transistors Q1 to Q4. That is, the first inverter INV1 has a DC power supply DC1, transistors Q1 to Q4, a transformer T1, and a rectifier DB1, and the second inverter INV2 has a DC power supply DC1, transistors Q1 to Q4, a transformer T1, and a rectifier DB2. . The output currents of these inverters are smoothed by the inductors L1 and L2, respectively, and supplied to the chamber 101 and the target 104.

  On the other hand, an arc sensor (Asen1) is provided on the output side of the power source. The arc sensor detects “arc discharge” when the output voltage decreases. The detection output is input to the one-shot timers TMR1 and TMR2. The control signals from these timers are input to the AND gate together with the current detection signal (current), and the photocouplers (PC11 to PC32) are controlled by the output signals (arc signal, ack signal). The current detection signal (current) is a control signal for enabling arc determination according to the output current from the power source. That is, when the output current reaches a predetermined value, the current detection signal (current) is turned on, and the control operation by the arc sensor is permitted.

  The one-shot timer TMR1 manages the arc signal. That is, the one-shot timer TMR1 outputs a control signal for turning on the arc signal during a predetermined “extinguishing period”. On the other hand, the one-shot timer TMR2 manages the ack signal. That is, the one-shot timer TMR2 outputs a control signal for turning off the ack signal for a predetermined “restoration period” after the “extinguishing period” elapses.

  When both the arc signal and the ack signal are on, the photocouplers (PC11 to PC32) are turned on, and the arc cutoff operation is performed.

  Hereinafter, the configuration of the power source of this comparative example will be described in more detail with reference to the operation of the power source in the sputtering process.

  First, when performing sputtering, the inverters INV1 and INV2 are started, the switching elements Q5 and Q6 are closed, and the insulated gate bipolar transistors IGBT1 and IGBT2 that short-circuit the inductor current are opened. Output to the target 104.

  On the other hand, when arc discharge occurs in the chamber, the impedance of the chamber decreases and the output voltage decreases. When the arc sensor (Asen1) detects an arc discharge due to such a voltage drop, the arc sensor (Asen1) starts the one-shot timer TMR1. The one-shot timer TMR1 outputs an ON signal during a predetermined “extinguishing period”, and based on this, opens the switching elements Q5 and Q6 via the photocouplers (PC11 to PC32) and the AND gate, The insulated gate bipolar transistors IGBT1 and IGBT2 are closed.

  Then, reverse voltage is applied to the chamber from the reverse voltage source DC2 through the insulated gate bipolar transistors IGBT2, IGBT1, reverse arc prevention diodes DA1, DA2, the chamber, and the reverse voltage source DC2, and the arc current is rapidly cut off. The At this time, the currents flowing through the inductors L1 and L2 are stored by the closed circuit of the diode D1 and the insulated gate bipolar transistor IGBT1, and the diode D2 and the insulated gate bipolar transistor IGBT2, respectively.

  The “extinguishing period” for outputting the reverse voltage is managed by the operation time of the one-shot timer TMR1. Simultaneously with the end of the “arcing period”, the one-shot timer TMR2 is started. The one-shot timer TMR2 outputs a control signal for turning off the ack signal during the “recovery period”. That is, during the “recovery period”, the photocouplers (PC12, PC22, and PC32) are turned off regardless of whether or not an arc is detected. Then, the insulated gate bipolar transistors IGBT1 and IGBT2 are opened, the switching elements Q5 and Q6 are closed, and a forward current (current direction for sputtering) is output.

  When the one-shot timer TMR2 stops, the “recovery period” ends, returns to the state before the operation of the one-shot timer TMR1, and when arc discharge is detected again, the above-described arc interruption operation is repeated. On the other hand, if arc discharge is not detected, the output of sputtering current is continued as it is.

  In the power source of the comparative example described above, in order to reduce the damage caused by the arc discharge, the time from the occurrence of the arc discharge to the interruption of the output current (arc response time) must be shortened. However, in the case of the power source of the comparative example shown in FIG. 2, in order to ensure synchronization and insulation for a plurality of insulated gate bipolar transistors IGBT (IGBT1, IGBT2), a signal that detects arc discharge is a photocoupler PC11. ~ Transmitted via PC32. However, in such a circuit configuration, the arc response time becomes longer by the signal transmission time (about 1 microsecond) of the photocoupler, and the arc discharge damage may be increased.

Accordingly, the present inventors have led to the power supply as illustrated in Figure 1.

  That is, as can be seen from a comparison between FIG. 1 and FIG. 2, arc sensors (Asen10, Asen20, Asen30) are newly provided to control the switching elements and IGBTs without using a photocoupler. Hereinafter, an arc sensor that transmits a signal via a photocoupler is referred to as a “general arc sensor”, and an arc sensor that transmits a signal without passing through a photocoupler is referred to as an “individual arc sensor”.

  The detection threshold values of these individual arc sensors (Asen10, Asen20, Asen30) and the general arc sensor (Asen1) can be set differently. That is, in a state (range) where the individual arc sensors (Asen10, Asen20, Asen30) detect arc discharge, the general arc sensor (Asen1) may be set so as to detect arc discharge.

  For example, the individual arc sensor determines “arc discharge” when the output voltage to the chamber is minus 150 volts or more (absolute value is 150 volts or less). On the other hand, the general arc sensor can be set to determine “arc discharge” when the output voltage is minus 180 volts or more (absolute value is 180 volts or less). That is, the general arc sensor can detect an arc earlier than the individual arc sensor. This will be described in detail later.

  The individual arc sensors (Asen10, Asen20, Asen30) are provided for each switching element and insulated gate bipolar transistor IGBT operating with the same power source. The control circuit that operates based on the output from these sensors is based on the logical sum of the detection output from the individual arc sensors (Asen10, Asen20, Asen30) and the output from the photocouplers (PC11, PC21, PC31). Operate.

  However, the response time of signal transmission differs between the two. That is, the individual arc sensors (Asen10, Asen20, Asen30) transmit signals without going through the photocoupler, so the response time is short, but the general arc sensor (Asen1) goes through the photocouplers (PC11, PC21, PC31). Response time is long. On the other hand, when the general arc sensor (Asen1) determines “arc discharge”, the one-shot timer TMR1 is operated to output a cut-off signal (arc) during the “extinguishing period”, and then the one-shot timer The TMR2 is operated to stop the ack signal during the “recovery period”.

  In the power source shown in FIG. 1, by performing logical operations on the outputs from the photocouplers (PC11 to PC32) and the detection outputs from the individual arc sensors (Asen10, Asen20, Asen30) in the logic circuit, respectively, Performs a shut-off action.

  (1) When the general arc sensor (Asen1) detects arc discharge and a control signal for arc interruption is output from the photocouplers (PC11, PC21, PC31), the arc interruption operation is performed.

  (2) Even before the control signal for arc interruption is output from the photocoupler (PC11, PC21, PC31), the individual arc sensors (Asen10, Asen20, Asen30) detect the arc discharge and the detection signal is output. When it is output, the arc is interrupted.

  (3) During the “recovery period” managed by the one-shot timer TMR2 activated by the general arc sensor (Asen1), the general arc sensor (Asen1) and the individual arc sensors (Asen10, Asen20, Asen30) perform arc discharge. Even if it is detected, the arc is not interrupted.

  (4) When the arc interrupting operation is prohibited for the purpose of controlling the operation of the power source, the interrupting operation is not performed regardless of the detection of each arc sensor.

Hereinafter, the operation of the power supply according to the related technology will be described with specific numerical values.

  In the following specific example, the detection threshold of the individual arc sensors (Asen10, Asen20, Asen30) is set to minus 150 volts, the detection threshold of the general arc sensor (Asen1) is set to minus 180 volts, The “arc period” and “recovery period” are each 3 microseconds.

  First, when the power supply is activated, each arc sensor determines “arc discharge” if there is no output voltage from the power supply. However, since there is no output current, no control signal (current) is obtained and no ack signal is output. For this reason, the photocouplers (PC11 to PC32) remain off. As a result, the switching elements Q5 and Q6 are turned on (ON), and the insulated gate bipolar transistors IGBT1 and IGBT2 are turned off (OFF). Therefore, when the inverter is started, the power supply outputs a DC voltage.

  Next, plasma ignition and sputtering start are as follows. That is, when the inverters INV1 and INV2 are activated by switching of the transistors Q1 to Q4, a DC voltage is output via the transformer T1 and the diode bridges DB1 and DB2, and the voltage supplied to the chamber 101 gradually increases.

  The plasma ignition voltage is, for example, minus 200 volts or less, and at this time, the arc determination level of the arc sensor is minus 150 volts (Asen10, Asen20, Asen30) or minus 180 volts (Asen1). That is, each arc sensor does not detect arc discharge, and the arc detection signal from the sensor is turned off.

  When a predetermined condition is satisfied, discharge starts in the chamber, current flows, plasma is formed, and sputtering is started. At the same time, current begins to flow, and when a predetermined current threshold is exceeded, a control signal (current) is obtained, an ack signal is output, and the photocouplers (PC12, PC22, PC32) are turned on. Since there is no photocoupler (PC11, PC21, PC31), the output of the DC voltage / current in the forward direction (voltage direction for performing sputtering) is continued.

  Then, when arc discharge occurs during sputtering, the following operation is performed. That is, the discharge voltage during normal sputtering is minus 400 volts or more (for example, around minus 750 volts), but when the arc discharge starts, the load voltage (that is, output voltage) rises in a short time (absolute value decreases). To do. When the output voltage rises above minus 180 volts (approaches zero volts), the general arc sensor (Asen1) responds first, outputs an arc detection signal, starts the one-shot timer TMR1, and "extinguish period" During this period, the arc signal is output. However, the signal transmission of the photocouplers PC11, PC21, and PC31 has a delay of about 1 microsecond, for example.

  If the output voltage reaches minus 150 volts during this time, the individual arc sensors (Asen10, Asen20, Asen30) respond and output an arc detection signal to the OR gate. The output of the OR gate outputs a reverse voltage by opening the switching elements Q5 and Q6 and closing the insulated gate bipolar transistors IGBT1 and IGBT2 via the AND gate. Since there is no photocoupler in the output path from the individual arc sensor, the signal transmission is quick and the arc breaking operation is started in a very short time. Therefore, the arc interruption operation can be started prior to the arc interruption operation via the photocoupler.

  On the other hand, when the “extinguishing period” managed by the one-shot timer TMR1 ends, the ack signal is turned off during the “restoration period” by the one-shot timer TMR2, so that the individual arc sensors (Asen10, Asen20, Asen30) ), The forward current output is resumed regardless of the detection signal.

  If the arc discharge continues when the “restoration period” ends and the ack signal is turned on, each arc sensor issues a cutoff command and restarts the arc cutoff operation again.

  On the other hand, if the arc is gone when the “recovery period” ends and the ack signal is turned on, the chamber voltage exceeds the detection threshold of the arc sensor, so each arc sensor issues a shutoff command. Continue sputtering without taking out.

As described above, according to this related art, when an arc discharge occurs and the chamber voltage rises rapidly, the control circuit via the individual arc sensors (Asen10, Asen20, Asen30) starts the shut-off operation quickly. On the other hand, the “extinguishing period” and the “recovery period” are always managed by the general arc sensor (Asen1). Therefore, even if a plurality of arc sensors are provided, the “extinguishing period” and the “recovery period” are kept constant, and there is no occurrence of “shift” in the operation timing.

  That is, in the case where a plurality of arc sensors are provided, in reality, there are many cases where “variation” occurs in the detection threshold according to the individual difference of each arc sensor. On the other hand, according to the present embodiment, it is possible to unify the operation timing by sharing the one-shot timer for managing the “extinguishing period” and the “restoring period”.

  FIG. 3 is a graph showing changes in the output voltage when normal arc discharge occurs.

FIG. 4 is a schematic diagram showing the operation of the power supply according to the related art when such arc discharge occurs.

  That is, during normal sputtering, for example, a voltage of about minus 750 volts is output. On the other hand, when arc discharge occurs, the voltage rapidly increases (absolute value decreases) to, for example, about minus 80 volts. First, it exceeds the detection threshold value (for example, minus 180 volts) of the general arc sensor (Asen1), and further exceeds the detection threshold value (for example, minus 150 volts) of the individual arc sensors (Asen10, Asen20, Asen30). However, in the case of arc discharge as shown in FIG. 3, since the voltage rises rapidly, the detection timing by these arc sensors is very close.

  When the general arc sensor (Asen1) detects a drop in voltage, the one-shot timer TMR1 is started to start measurement of the “arcing period”. At the same time, a cutoff operation (reverse voltage output) via the photocouplers (PC11 to PC32) is started. At this time, a delay occurs in the operation of the photocoupler.

  On the other hand, the individual arc sensors (Asen10, Asen20, Asen30) start a cut-off operation without passing through the photocoupler when arc discharge is detected. As a result, the reverse voltage can be quickly applied to the chamber prior to the general arc sensor, and the arc discharge can be quickly interrupted.

  On the other hand, the management of the “arcing period” and the “recovery period” is performed by the one-shot timers TMR1 and TMR2 connected to the general arc sensor. Will not occur.

As illustrated in FIG. 3, arc discharge in which the chamber voltage rapidly increases (absolute value decreases) often occurs, for example, when various metals such as aluminum are sputtered. In such sputtering, for example, large electric power of about 20 to 30 kW is often applied, and arc damage is great, so it is desirable to extinguish the arc quickly. According to the related art , a particularly remarkable effect is obtained in that the interruption operation can be started very quickly by the individual arc sensor.

  On the other hand, “abnormal discharge” in which the voltage gradually increases (the absolute value of the voltage gradually decreases) may occur during sputtering.

  FIG. 5 is a graph illustrating a voltage change when an abnormal discharge occurs.

FIG. 6 is a schematic diagram showing the operation of the power supply according to the related art when such abnormal discharge occurs.

For example, when sputtering SiO ₂ or the like, the voltage may gradually increase as illustrated in FIG. The rising time may be relatively long, for example, about 20 milliseconds. When such “abnormal discharge” occurs, first, the general arc sensor (Asen1) detects a voltage abnormality and starts measurement of the “arcing period”, and at the same time, the photocouplers (PC11 to PC32) are turned on. The shut-off operation is started.

  When the chamber voltage further rises, the individual arc sensors (Asen10, Asen20, Asen30) detect a voltage abnormality and start an interruption operation. However, when the chamber voltage rise rate is small as illustrated in FIG. 5, the output of the reverse voltage by the general arc sensor is started first. That is, as shown in FIGS. 3 and 4, the order of operations is reversed from the case where the voltage changes rapidly.

  In general, the detection sensitivity of the general arc sensor or the individual arc sensor may include “variation” caused by individual differences. In such a case, as illustrated in FIG. 5, if the voltage changes slowly, the timing of the shut-off operation by each sensor may be greatly shifted. If the timing of the shut-off operation is greatly shifted for each sensor, the operation of the power supply may become unstable.

  On the other hand, if the detection level is set so that the general arc sensor detects abnormal discharge earlier than the individual arc sensor, the voltage slowly changes as illustrated in FIG. The interruption operation by the general arc sensor can be executed first. As a result, it is possible to solve the problem caused by variations in operation timing for each sensor. In such a case, the “arcing period” and the “recovery period” are managed by the general arc sensor, and there is no “deviation” in the operation timing.

Further, “abnormal discharge” as illustrated in FIG. 5 often occurs when SiO ₂ or the like is sputtered with a relatively low input power of, for example, about ₂ to 3 kW. Therefore, in such a case, even if a cut-off operation including a delay of the photocoupler is used, the damage of the discharge can be relatively small.

As described above, according to this related technology , an individual arc sensor that performs a shut-off operation without using a photocoupler is added, and the management of the “extinguishing period” and the “recovery period” is a common one-shot timer. By performing the above, it is possible to provide a power source that performs a quick and unified shut-off operation.

(Second related technology )
Next, as a second related technique of the present invention, a power supply capable of preventing the application of overpower when re-applying forward power after an arc interruption operation will be described.

FIG. 7 is a schematic diagram illustrating a main part of a power supply according to the related technology .

FIG. 8 is a schematic diagram showing a main part of a power source of a comparative example that was experimentally manufactured by the inventor in the process of reaching the related technology . 7 and 8, the same elements as those described above with reference to FIGS. 1 to 6 are denoted by the same reference numerals, and detailed description thereof is omitted.

  Hereinafter, the power source of the comparative example shown in FIG. 8 will be described first.

This power supply also performs sputtering by outputting the forward DC output from the two inverters INV1 and INV2 to the chamber, similar to that described above with respect to the first related technology .

  The output power is feedback controlled. That is, the output voltage sensor (Vsen) and the output current sensor (Csen1) measure the output voltage and the output current, respectively, and integrate these in the integration circuit MTL to obtain the actual output power. Then, a command current value is calculated by comparing the output power value and a set value (Pset) input from a higher-level control device (not shown) separately from the output power value in a power comparison circuit (Perr). . Then, the command current value and the measured value from the current sensor (Csen1) are compared in the current comparison circuit (Cerr), and input to the PWM circuit (PWM) to perform PWM (pulse width modulation) control of the inverter.

  Now, when arc discharge occurs during sputtering, the voltage of the chamber 101 decreases. When the arc sensor (Asen) detects an arc discharge due to the decrease in the output voltage, first, the arc sensor (Asen) executes an operation described below during a predetermined “extinguishing period”.

  That is, the sample hold switch (S & Hold) is opened, and the output path of the command current value from the power comparison circuit (Perr) to the current comparison circuit (Cerr) is cut off. Then, the previous command current value is output to the current comparison circuit (Cerr) by the holding capacitor CH connected in series with the path.

  When the arc sensor detects an arc discharge, the insulated gate bipolar transistors IGBT1 and IGBT2 are closed by a control circuit (not shown), the switching elements Q5 and Q6 are opened, and the insulated gate bipolar transistor IGBT1 from the reverse voltage source DC2 is opened. A reverse voltage is output through the path of the IGBT 2, the chamber, and the reverse voltage source DC 2 to quickly cut off the chamber current.

  At the same time, by forming a closed circuit of the diode D1 and the insulated gate bipolar transistor IGBT1, and the diode D2 and the insulated gate bipolar transistor IGBT2, the currents of the inductors L1 and L2 are stored.

  After performing the above operation during the “extinguishing period”, the insulated gate bipolar transistors IGBT1 and IGBT2 are opened and the forward current is output during a predetermined “restoration period” regardless of whether or not arc detection is performed. To do. If the arc discharge is detected after the “restoration period”, the operation of the “arc extinguishing period” described above is repeated. If no arc discharge is detected, the sputtering current is output as it is.

  The currents of the inductors L1 and L2 are subjected to constant current control with the target current value immediately before the occurrence of arc held in the capacitor CH as a target until the “extinguishing period” ends.

  However, if a serious arc discharge occurs, it may take a long time to completely extinguish the discharge even if the “extinguishing period” and the “recovery period” are repeated. In the case of the circuit configuration shown in FIG. 8, the current sensor (Csen1) during this period can monitor the inductor current only during the “recovery period”. Further, when a current error due to a transient response during switching of the insulated gate bipolar transistors IGBT1 and IGBT2 and the switching elements Q5 and Q6 is included, the measured value in the current sensor tends to be smaller than the actual inductor current. For this reason, even if the constant current control is performed with the command current value held in the capacitor CH fixed, the forward current flowing during the “recovery period” increases. As a result, arc discharge may reoccur during the “restoration period” by applying forward overpower.

  When overpower is applied to an arc generation point (hot spot) that has already been formed, the temperature of the hot spot rises rapidly, and arc damage such as “splash” that scatters around is likely to occur. Such damage is particularly noticeable when sputtering is performed by connecting a plurality of power supplies in parallel or when the power supplies are operated with high power.

Therefore, the present inventor has reached this related technology .

Hereinafter, the power supply of the related technology will be described in detail with reference to FIG.

In this related technology , in addition to the output current sensor (Csen1), the inductor current sensor (
Csen2) is provided. The output current sensor (Csen1) is provided between the closed circuit for storing the inductor current formed at the time of arc interruption ("arc extinction period") and the power supply output terminal. In addition, the inductor current sensor (Csen2) is provided in a closed circuit for storing the inductor current when the arc is interrupted, and at a location where the inductor current flows even during forward output from the power source. Specifically, the inductor current sensor (Csen2) can be provided at a location adjacent to the inductor L1 or L2.

  The output current sensor (Csen1) has a role of operating the power source at a constant power and monitoring an actual output current. That is, the power supply performs constant power control of the output and actual current monitoring based on the measurement data of the output current sensor (Csen1).

  On the other hand, the inductor current sensor (Csen2) has a role of measuring the inductor current even during the “arc-extinguishing period” in which the arc interruption operation is performed. That is, the power supply performs constant current control during operation including the “extinguishing period” based on the measurement data of the inductor current sensor (Csen2).

  7 shows a specific example in which the inductor current sensor (Csen2) is provided in the vicinity of the inductor L1, the inductor current sensor (Csen2) may be provided in the vicinity of the inductor L2.

Hereinafter, the operation of the power supply of this related technology will be described.

  First, at the time of sputtering, a measured value of output power is obtained by multiplying (MTL) the measured voltage value by the output voltage sensor (Vsen) and the measured current value by the output current sensor (Csen1). Then, with respect to the set power value (Pset) input from a higher-level control device (not shown), an error of the output power measurement value is calculated in the power comparison circuit (Perr), and a command current value to be output is determined.

  With respect to the command current value thus obtained, the current comparison circuit (Cerr) calculates an error from the current measurement value by the inductor current sensor (Csen2), and the PWM circuit (PWM) determines the pulse width of the inverter. To do.

  On the other hand, when an arc discharge occurs, the arc sensor (Asen) detects the arc discharge by a decrease in the output voltage, and starts the arc interruption operation managed by the “extinguishing period” and “recovery period” as described above. To do.

  During the “arc-extinguishing period”, the output current sensor (Csen1) measures the actual current flowing in the chamber, outputs it as a measured current value, and provides current information to the power comparison circuit (Cerr) through the multiplier (MTL). . However, since the command current value supplied to the current comparison circuit (Cerr) is data held in the capacitor CH when the arc occurs, it does not vary. On the other hand, the chamber current measured by the output current sensor (Csen1) can be taken out from the monitor terminal (moni) to check the arc extinction state of the arc discharge.

  In contrast, the output current sensor (Csen1) measures the inductor current stored in the closed circuit including the insulated gate bipolar transistor IGBT1, the diode D1, and the inductor L1 even during the “extinguishing period”. Then, a measured value is input to the current comparison circuit (Cerr), and constant current control based on an error from the held command current value is executed. The inductor current is also stored in the “extinguishing period”, but if the inductor current fluctuates for some reason, constant current control is performed with the command current value as a target. Therefore, even when the “extinguishing period” ends and the “restoration period” starts, the problem that excessive electric power is supplied to the chamber can be solved.

  When the arc discharge is extinguished, the chamber voltage recovers during the “recovery period”. When the increase of the output voltage is confirmed by the arc sensor (Asen), the sample hold switch (S & Hold) is closed and the power comparison circuit (Perr ) Is input to the current comparison circuit (Cerr). The current comparison circuit (Cerr) controls the currents of the inductors L1 and L2 according to the new command current value, and outputs them to the chamber 101.

  As described above, according to the present embodiment, the inductor current is measured by the inductor current sensor (Csen2) adjacent thereto even while arc discharge occurs in the sputtering chamber and the power source performs the arc cutoff operation. Feedback control. As a result, the current flowing through the inductors L1 and L2 can be maintained in the state before the occurrence of the arc discharge even during the “extinguishing period”, and the reoccurrence of the arc discharge due to the application of overpower after the arc is extinguished. Can be eliminated.

Figure 9 is a schematic view showing a power variation according to the related art. Also in this figure, the same elements as those described above with reference to FIGS. 1 to 8 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In this modification, the closed circuit for individually storing the inductor current is omitted. That is, as can be seen from comparison with FIG. 7, the path including the diodes D1 and D2 is omitted, and the switching elements Q5 and Q6 are also omitted.

  In the case of this power source, during the “extinguishing period”, the insulated gate bipolar transistors IGBT1 and IGBT2 are closed to apply a reverse voltage from the reverse voltage source DC2 to the chamber and simultaneously flow through the inductor L1. The current is stored in a circuit including the inductor L1, the rectifier DB1, and the insulated gate bipolar transistor IGBT1, and the current flowing through the inductor L2 is also stored in the circuit including the inductor L2, the rectifier DB2, and the insulated gate bipolar transistor IGBT2. Is done.

  Even during the “extinguishing period”, the actual inductor current is measured by the inductor current sensor (Csen2), and feedback control is performed, whereby appropriate forward power can be input during the “recovery period”. In other words, it is possible to eliminate the recurrence of arc discharge due to excessive input of electric power again.

(Third related technology )
Next, as a third related technique of the present invention, as in the second related technique , in a power source provided with an output current sensor and an inductor current sensor, a “ground fault”, that is, a short circuit to the ground occurs. An explanation will be given of a power supply that has been improved so that it can cope with the situation.

FIG. 10 is a schematic diagram illustrating a main part of a power supply according to the related technology .

FIG. 11 is a schematic diagram showing a main part of a power source of a comparative example that was experimentally manufactured by the inventor in the process of reaching the related technology . Also in FIGS. 10 and 11, the same elements as those described above with reference to FIGS. 1 to 9 are denoted by the same reference numerals, and detailed description thereof is omitted.

  Hereinafter, the power source of the comparative example shown in FIG. 11 will be described first.

  As shown in FIGS. 7 and 9, this power source includes an output current sensor (Csen1) and an inductor current sensor (Csen2). As described above with reference to the second embodiment, However, the inductor current can be feedback controlled by the inductor current sensor (Csen2). In the figure, the sample hold switch (S & Hold), the hold capacitor CH, and the like are omitted for the sake of convenience.

  In the case of this power source, during normal forward output, the output power is calculated by calculating the product of the observed values of the output voltage sensor (Vsen) and the output current sensor (Csen1) of the output terminal positive electrode in the integrating circuit (MTL). obtain. A command current value (Cset) is obtained by comparing the output power with a power command value (Pset) from a higher-level control device (not shown) by a power comparison circuit (Perr). The inverter is PWM controlled via the PWM circuit (PWM) so that the observed values of the inductor current sensor (Csen2) match.

  However, the output of the power supply is a high voltage (for example, 1500 volts or more), and a “ground fault” as exemplified by the arrow GS in FIG. . That is, a short circuit due to “air arc discharge” or the like may occur between the high voltage portion of the power supply and the ground potential portion in the vicinity thereof.

  When such a “ground fault” occurs, a short-circuit current from the short-circuit point (arrow GS) to the ground potential of the chamber 101 flows through the inductor current sensor (Csen2) and the output current sensor (Csen1). Since this short-circuit current flows through the two current sensors, it cannot be determined even if the difference between them is calculated. In addition, the sputtering load usually has a constant voltage characteristic, and the voltage is maintained even if the forward current flowing therethrough decreases, so that it cannot be detected as a voltage change.

  That is, in the case of the power source shown in FIG. 11, even if a short-circuit current due to such a “ground fault” flows, it cannot be detected, and the current of the positive electrode P is controlled to be constant without recognizing an abnormality. And Then, since the current continues at the short-circuit portion (GS) where the ground fault has occurred, air arc discharge is maintained, and parts may be damaged.

The present inventor has arrived at the related art based on recognition of such a problem.

That is, in this related technique , first, as shown in FIG. 10, the output current sensor (Csen1) is disposed between the negative output terminal and the arc-blocking insulated gate bipolar transistor IGBT. Is provided between this output terminal and the reverse arc preventing diode DA1.

  This is because the high voltage portion where a ground fault is likely to occur is on the output (N terminal) side of the negative electrode of the power source, and further, is the output portion of the rectifier before current smoothing. When a ground fault occurs, a short-circuit current often flows from here, so that the short-circuit current does not flow through the output current sensor (Csen1). Output current sensor (Csen1).

  On the other hand, the inductor current sensor (Csen2) is installed on the ground side (P terminal side) from the rectifier (DB2) so that a short-circuit current flows. That is, the inductor current sensor (Csen2) is provided between the positive output terminal (P terminal) and the closest inductor L1. Further, an inductor current sensor (Csen2) is provided in a closed circuit formed when the insulated gate bipolar transistor IGBT for interrupting the arc is closed so that the inductor current can be measured even during the “extinguishing period”.

  As described above, when the current sensors are arranged and the measured values of the current sensors (Csen1, Csen2) do not match, it is determined as a “ground fault”. Specifically, for example, a resistance voltage dividing circuit is provided on the output side of these two current sensors to prepare a signal having a level of 90%. Then, the output signals of the current sensors (Csen1, Csen2) are input to the comparators CMP1, CMP2, and it is confirmed by AND gate that each exceeds 90% of the other.

  However, when arc discharge occurs and arc extinguishing operation is performed, the output current is cut off, but the inductor current is preserved, and these current values are different. Therefore, in the determination using the comparators CMP1 and CMP2, in order to exclude the state of the arc extinguishing operation, it is necessary to invalidate the comparison of these current sensors during the “extinguishing period” and for a predetermined time thereafter. For this reason, the output signal from the arc sensor (Asen) is input to the multi-trigger timer circuit (TMR), and the “extinguishing period” during the output of the timer and the predetermined time thereafter are confirmed by the comparators CMP1 and CMP2. Mask.

  On the other hand, if the above-mentioned confirmation by the comparators CMP1 and CMP2 is not obtained in the unmasked state, it is determined that there is a “ground fault” and, if necessary, the operation signal (RUN) of the power supply is passed through the timer circuit (TMR). ) Is turned off.

  As described above, when the “ground fault” is detected, for example, the operation of the power supply can be stopped for a predetermined time and an abnormality can be displayed on the operation monitor.

  At this time, the upper control device (not shown) that manages the operation of the power supply should stop the operation signal of the power supply when the operation of stopping the power supply due to the “ground fault” occurs frequently. Also good.

  On the other hand, there are cases where a plurality of such power supplies are provided and connected in parallel to output power to the sputtering apparatus.

  FIG. 12 is a schematic diagram showing a sputtering system in which a plurality of power supplies 110 are connected in parallel as described above. Even in such a case, the “ground fault” can be determined by comparing the measured values of the output current sensor (Csen1) and the inductor current sensor (Csen2) in each of the power supplies 110. Alternatively, measurement may be performed by the inductor current sensor (Csen2) in each power source 110, and the total value may be compared with the total value of output current from each power source 110 measured by an external current sensor provided separately.

Hereinafter, the operation of the power supply of the related technology will be described with specific examples. That is, the operation when the “ground fault accident” of the arrow GS occurs during operation at 500 volts and 2 amps will be described.

  First, at the time of sputtering, the outputs of the two inverters INV1 and INV2 are rectified by diode bridges, smoothed by the inductors L1 and L2, respectively, and supplied to the load via the output terminals P and N, and the positive electrode of the load is grounded. .

  The output voltage is measured with the voltage sensor (Vsen), the output current is measured with the current sensor (Csen1), the current value (Cset) for obtaining the command power is calculated, and the measurement result of the inductor current sensor (Csen2) is The operation of the inverter is adjusted so that this current value is obtained.

  When a “ground fault” occurs, the current flowing from the fault point (GS) returns to the ground at the load via the rectifier DB2, the inductor L1, the current sensor (Csen2), the rectifier DB1, and the P terminal. Therefore, the output current sensor (Csen1) measures the current of 2 amperes flowing through the load, while the inductor current sensor (Csen2) has the load current of 2 amperes and a short circuit current that is not overcurrent on the primary side of the inverter (for example, Measure 22 amps, about 20 amps). When the limit on the primary side of the inverter is exceeded, the power supply can be stopped as “overcurrent”.

  In this case, since the measured value of the output current sensor (Csen1) is smaller than 19.8 amperes which is 90% of the inductor current sensor (Csen2), it is determined as “abnormal”, and the operation signal (RUN) of the PWM circuit (PWM) is determined. ) Is cut off, the power supply is stopped, and the operation monitor (not shown) is turned off.

  Thereafter, the power supply may be restored after a predetermined time has elapsed. That is, when the stop time managed by the timer circuit (TMR) ends, the operation of the power supply can be resumed. At this time, if the “ground fault accident” is cancelled, the sputtering is resumed from the ignition operation. If the “ground fault accident” continues, the power supply is stopped again by the above-described operation.

  On the other hand, when the “ground faults” frequently occur, the automatic power supply recovery may be stopped. For example, a control device (not shown) for the power supply monitors the operation monitor of the power supply, and when frequent stoppages due to “ground faults” occur, it is determined that the abnormal state cannot be automatically restored, and the operation signal (RUN) may be stopped to stop the apparatus, and an alarm may be issued to an operator or the like as necessary. In this way, the damage of the “ground fault” can be further reduced and the cause can be quickly removed.

As described above, according to this related technique, when a “ground fault” occurs in the high voltage portion inside the power supply and an excessive short circuit current flows, the measured values of the two current sensors are different. It can be detected accurately. That is, even if the short-circuit current is within a range that does not become an overcurrent of the inverter, “abnormality” can be detected and the power supply can be stopped. As a result, it is possible to prevent problems such as damage to parts due to a “ground fault”, stop of the production process, and formation of defective products.

(First Embodiment)
Next, as a first embodiment of the present invention, a power supply capable of preventing an overcurrent from being applied when plasma is ignited or when arc discharge occurs will be described.

  FIG. 13 is a schematic diagram showing the main part of the power supply according to the present embodiment.

  FIG. 14 is a schematic diagram showing a main part of a power source of a comparative example that was experimentally manufactured by the inventors in the course of reaching the present embodiment. Also in FIGS. 13 and 14, the same elements as those described above with reference to FIGS. 1 to 12 are denoted by the same reference numerals, and detailed description thereof is omitted.

  Hereinafter, the power source of the comparative example shown in FIG. 14 will be described first.

  Such a power source is managed, for example, by a host control device (not shown), and the power output from the power source and the processing time are managed, and an operation command (RUN) and a power command value (Pset) are input. The power supply to which these control signals are input smoothes and outputs the inverter current rectified by starting the inverter with an inductor.

  The inverter control circuit starts the error integration calculation of the output power by the power comparison circuit (Perr), but the command current value (Cset) increases from zero when the power supply is started. However, since the amplification factor in the subsequent stage is high, the output voltage rises at a stretch to the plasma ignition voltage.

  Until the plasma is ignited, the output current is zero even if the output voltage rises, so the command current value (Cset) increases with time.

  On the other hand, when the plasma is ignited, a current flows through the load. Then, an error between the output power calculated (MTL) according to the output voltage and the output current measured by the voltage sensor (Vsen) and the output current sensor (Csen1) and the command power is integrated by the power comparison circuit (Perr). To determine the command current value (Cset). The current comparison circuit (Cerr) PWM-controls the inverter in proportion to the error between the inductor current measured by the current sensor (Csen2) and the command current (Cset).

  On the other hand, a power source in which an arc discharge is generated during sputtering and a chamber voltage drop is detected as a drop in output voltage closes the insulated gate bipolar transistors IGBT1 and IGBT2 and opens the switching elements Q5 and Q6 to open the reverse voltage source DC2. The reverse voltage is output from and the output current is cut off during the specified “extinguishing period”.

  During arc discharge, there is almost no output power because of the interruption operation, and the error from the command value (Pset) increases, so the command current value (Cset) increases. This is an operation command opposite to the current interruption. Therefore, for example, it is necessary to provide a sample hold switch (S & Hold) and a hold capacitor CH as illustrated in FIG. 7 to hold and adjust the command current value (Cset).

  However, in the case of the power source shown in FIG. 14, if the waiting time until the plasma ignition is long, the command current value (Cset) at the time of ignition becomes large and an overshoot state may occur. As a result, an excessive current may be input during ignition.

  In addition, when arc discharge occurs, the output current is suppressed by current control after measuring the increased current due to the drop in the output voltage, but the current suppression operation is delayed because the response of the inductor current is slow. There is a case. As a result, the initial large instantaneous current at which arc discharge occurs cannot be suppressed, and arc damage may increase.

  The present inventor has reached the present embodiment based on the recognition of the problem.

  That is, in this embodiment, as illustrated in FIG. 13, a division circuit (DIV) is provided, and (command power value ÷ output voltage) is calculated to calculate a current value to be output. The output voltage input to the divider circuit (DIV) is the measurement data of the voltage sensor (Vsen1). By providing a limiter (limit), the minimum voltage for normal discharge is set as the limit value. The minimum voltage value of normal discharge, that is, the limit value can be set to, for example, minus 150 volts.

  Then, an error of the current measured by the output current sensor (Csen1) is calculated in the current comparison circuit (Cerr1) with respect to the current value to be output thus obtained. The output of the current comparison circuit (Cerr1) is connected to a switch SW that stops the integration operation. The integration operation is not performed when the switch SW is closed, and the integration operation is performed when the switch SW is open. Therefore, by controlling the switch SW with the output current sensor (Csen1) and the comparator (Cmp), it is possible to control so that the integration operation is performed only when the output current is equal to or greater than a predetermined value.

  The threshold value for operating the switch SW, that is, the judgment value as to whether or not to perform the integration operation, can be, for example, half (1/2) of the current that the output current should be output.

  According to the configuration described above, error integration can be started from the start of sputtering during power control. The determination of the start of sputtering can be made by the fact that the measured value by the output current sensor (Csen1) has increased to a predetermined value.

  In a time zone during which this integration is not executed, (current value to be output = command power value ÷ output voltage) can be set as a current command value.

  On the other hand, in the present embodiment, by providing an output voltage feedback control circuit, the output of the inverter can be narrowed down when the voltage drops. That is, as shown in FIG. 13, an inductor voltage sensor (Vsen2) for measuring the voltage of the inductor L1 is provided. Further, the voltage applied to the inductor L1 is calculated by comparing the command current value (Cset) of the inductor with the output of the inductor current sensor (Csen2) in the current comparison circuit (Cerr2). Then, the calculated value is compared with the output of the inductor voltage sensor (Vsen2) in the voltage comparison circuit (Verr), and the PWM control of the inverter is executed by the output via the PWM circuit (PWM). In this way, feedback control of the output voltage becomes possible, and the output of the inverter can be reduced when the inductor voltage drops.

  Hereinafter, the operation of the power supply of the present embodiment will be described in detail with reference to specific examples.

  First, at the time of start-up, the command power value (Pset) to be operated is input, but the output voltage is zero, and the current is calculated with the lowest normal discharge voltage value, that is, the limit value minus 150 volts. For example, when the output power is set to 300 watts, 2 amperes becomes the start value of the command current value (Cset). Although both the inductor current and the inductor voltage are zero, the transistors Q1 to Q4 do not operate until the operation signal (RUN) is input.

  When the operation signal (RUN) is input from the host control device, the inverter is activated. There is no inductor current and no inductor voltage until plasma ignition. Therefore, the output voltage rises to an ignition voltage that is separately limited.

  When glow discharge starts in the chamber 101, an output current (= inductor current) starts to flow, and the output voltage rises. When the output voltage is minus 400 volts, the current to be output is 0.75 ampere, and when the output current reaches 0.375 ampere, which is half of that, the switch SW is opened and integration of the current error is started.

  If the inductor current is smaller than the command current value, the PWM circuit (PWM) operates so that the inductor voltage becomes positive, and if the inductor current is larger, the PWM circuit (PWM) controls the inverter so that the inductor voltage becomes negative.

  On the other hand, when arc discharge occurs, the following operation is performed.

  That is, when arc discharge starts in the chamber 101, the output voltage drops. Then, the power source detects this by an arc sensor (not shown), and turns on the insulated gate bipolar transistors IGBT1 and IGBT2 to output a reverse voltage. At the same time, since the inductor voltage becomes positive and the input to the PWM circuit (PWM) decreases rapidly, the inverter stops for a moment to prevent an increase in current. Thereafter, when the arc interruption is finished and the sputtering is resumed, the current to be outputted is compared with the inductor current, and the inverter outputs the voltage necessary for the inductor.

  As described above, according to the present embodiment, the target current value after plasma ignition is determined depending on the set power and the output voltage regardless of the discharge waiting time until ignition. Therefore, even when it takes time to ignite, current control can be started without overshoot.

  In addition, according to the present embodiment, when arc discharge starts, the inductor voltage sensor (Vsen2) can detect the drop in the inductor voltage and immediately reduce the duty ratio of the inverter without waiting for the inductor current to increase. As a result, arc damage due to overcurrent can be suppressed.

(Second Embodiment)
Next, a second embodiment of the present invention, the power supply system for a magnetron having a stop circuit described above for the first embodiment will be described. That is, a forward power is supplied to the magnetron to cause an oscillation operation, and a reverse voltage is applied from the reverse bias voltage source charged by the above-described charging operation even when a sudden short-circuit current occurs due to any cause. Thus, the current can be cut off quickly.

  FIG. 15 is a conceptual diagram illustrating a configuration in which the power supply of the present invention is used for magnetron oscillation. That is, this figure represents a microwave generation system using a magnetron.

  The power supply 110 of this system applies a predetermined high DC voltage to the magnetron 200 to oscillate it. As the power source 110, the power source of the present invention described above with reference to FIGS. 1 to 14 can be used. The microwave power generated by the oscillation of the magnetron 200 is supplied to the load 500 through the isolator 310, the microwave sensor 320, and the microwave matching unit 340 using the waveguide as a transmission path. Further, a feedback signal FS is supplied from the sensor 320 to the inverter of the power source 110, and the output power of the microwave is controlled.

  Even in such a system, the forward power is supplied from the power source 110 to the magnetron 200 to cause an oscillation operation, and a physical short circuit or discharge occurs in the magnetron 200. According to the embodiment, a quick and reliable blocking operation can be executed.

Further , according to the present invention , the inductor current can be appropriately measured and feedback controlled even in such a cut-off operation, so that problems caused by applying excessive power after the cut-off operation can be prevented. .

Further , according to the present invention , the problem that the target current value overshoots until the load shifts to the steady state is solved, and furthermore, when an impedance decrease such as arc discharge occurs, an excessive current is also generated. Can be prevented.

  The embodiments of the present invention have been described above with reference to specific examples. However, the present invention is not limited to these specific examples.

  For example, in FIGS. 1 to 14, a power supply provided with two inverters INV1 and INV2 is illustrated, but the present invention is not limited to this. That is, the present invention can be similarly applied to a power supply of a so-called “multi-stage inverter configuration” in which three or more inverters are provided, and the same operation and effect can be obtained.

  On the other hand, the configuration, structure, number, arrangement, shape, material, etc. of each part in the power source, sputtering power source and sputtering apparatus of the present invention are not limited to the above specific examples, and those appropriately selected and adopted by those skilled in the art, As long as the gist of the present invention is included, it is included in the scope of the present invention.

  More specifically, for example, those exemplified by the symbols of MOS transistors and IGBTs (Insulated Gate Bipolar Transistors) as switching circuits, those exemplified by the symbols of varistors as protective elements, and the like, The present invention is not limited, and can be configured as a single electric element having a similar function or action or an electric circuit including a plurality of electric elements, and all these variations are included in the scope of the present invention.

  Similarly, the person skilled in the art appropriately changed the design of the specific configuration of the inverter, comparator, logic circuit, protection circuit, etc., and the number and arrangement of each circuit element including diodes, resistors, transistors, etc. Are within the scope of the present invention.

  In addition, all power supplies, sputtering power supplies, and sputtering apparatuses that include the elements of the present invention and that can be appropriately modified by those skilled in the art are included in the scope of the present invention.

It is a schematic diagram showing the principal part of the power supply concerning the 1st related technique of this invention. It is a schematic diagram showing the principal part of the power supply of the comparative example which this inventor made as an experiment in the process leading to 1st related technology . It is a graph showing the change of the output voltage when normal arc discharge occurs. It is a schematic diagram showing operation | movement of the power supply of the 1st related technique when arc discharge generate | occur | produces. It is a graph which illustrates the voltage change when abnormal discharge arises. It is a schematic diagram showing operation | movement of the power supply of the 1st related technique when abnormal discharge arises. It is a schematic diagram showing the principal part of the power supply concerning the 2nd related technique of this invention. It is a schematic diagram showing the principal part of the power supply of the comparative example which this inventor made as an experiment in the process leading to 2nd related technology . It is a schematic diagram showing the power supply of the modification concerning 2nd related technology . It is a schematic diagram showing the principal part of the power supply concerning the 3rd related technique of this invention. It is a schematic diagram showing the principal part of the power supply of the comparative example which this inventor made as an experiment in the process leading to 3rd related technology . It is a schematic diagram showing the sputtering system which connected the several power supply 110 in parallel. It is a schematic diagram showing the principal part of the power supply concerning the 1st Embodiment of this invention. It is a schematic diagram showing the principal part of the power supply of the comparative example which this inventor made as an experiment in the process to reach 1st Embodiment. It is a conceptual diagram which illustrates the structure which used the power supply of this invention for the oscillation of the magnetron. It is a schematic diagram showing the principal part structure of DC (direct current) sputtering apparatus. It is a schematic diagram showing an example of the power supply for sputtering.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Substrate 101 Chamber 104 Target 106 Pump 107 Gas supply source 108 Glow discharge 110 Power supply 120A, 120B Connection cable 150 Arc discharge 200 Magnetron 310 Isolator 320 Sensor 340 Microwave matching device 500 Load CH Hold capacitor Cmp Comparator CMP1, CMP2 Comparator DA1 Reverse Directional arc prevention diode DB1, DB2 Rectifier DC1 DC power supply DC2 Reverse voltage source DCPF Power supply section INV1, INV2 Inverter L1, L2 Inductor PC11-PC32 Photocoupler Q1-Q4 Transistor Q5, Q6 Switching element SW Switch T1 Transformer TMR1, TMR2 One shot・ Timer

Claims (5)

A power supply that outputs forward DC power smoothed by an inductor to a load,
A current target value is obtained based on a value obtained by dividing a target value of output power by a measured value of output voltage, and a current flowing through the inductor based on a measured value of the current flowing through the inductor and a target value of the current. controls,
When the absolute value of the measured value of the output voltage is lower than a certain value, overcurrent is suppressed by executing the division by the certain value instead of the measured value of the output voltage. Power supply. An integration circuit for integrating an error between a value obtained by dividing the target value of the output power by a measured value of the output voltage and an output current;
The integration circuit operates when a difference between a value obtained by dividing a target value of the output power by a measured value of an output voltage and an output current or a ratio falls within a certain range. Item 1. The power source according to item 1. Obtaining a target value of the voltage to be applied to the inductor based on the measured value of the current flowing through the inductor and the target value of the current;
The power supply according to claim 1 or 2, wherein a current flowing through the inductor is controlled based on a target value of the voltage and a measured value of the voltage applied to the inductor. A power supply for sputtering that forms a thin film by sputtering a target,
The power supply according to any one of claims 1 to 3 ,
A sputtering power source characterized in that the sputtering can be performed by applying the forward power to the target. A power supply for sputtering according to claim 4 ,
A vacuum chamber capable of accommodating the target and maintaining an atmosphere depressurized from atmospheric pressure;
A sputtering apparatus comprising:

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