JP4418424B2 - AC power supply apparatus and arc suppression method in the apparatus - Google Patents

Description

  The present invention relates to an AC power supply device, and more particularly, to an AC power supply device in which arc discharge is suppressed and an arc suppression method in the device.

  2. Description of the Related Art Conventionally, there are film forming apparatuses that manufacture semiconductors, liquid crystal substrates, and the like by forming various materials on a film formation substrate (hereinafter referred to as a substrate) using a film formation process such as vapor deposition or sputtering. For example, if this film forming apparatus is a sputtering apparatus, a glow discharge is generated in the vacuum vessel while introducing an inert gas such as argon, using the electrode to which the coating material is attached as a cathode. The deposited ions are made to collide with the cathode with an energy of several hundred eV corresponding to the discharge voltage, and the particles released by the reaction are made to form a volume on the substrate. The power supply device that supplies power to the film forming apparatus is a DC power supply or a high-frequency AC power supply, and applies the voltage, current, and power to the film forming apparatus with constant control. However, in these film forming processes, a thermal change occurs in an electrode for supplying electric power, the process state is not constant, and phenomena such as arc discharge and flashback occur. Conventionally, as a method for suppressing arc discharge, a method has been used in which arc discharge is detected, power supplied to the film forming apparatus is instantaneously stopped, and after the arc discharge is erased, the arc discharge is restarted.

  Also, there is one described in Patent Document 1 as a plasma processing apparatus that can shorten the interruption period and the return period when arc discharge occurs. As shown in FIG. 9, in the plasma processing apparatus, the DC voltage converted from the commercial power by the DC control unit 1 and taken out through the smoothing circuit 2 is sent to the inverter switching unit 3 to be AC (rectangular wave). And is supplied to the processing apparatus main body 6 through the step-up transformer 4 and the rectifying unit 5. 7 is a thyristor control unit, and 8 is an inverter control unit. Reference numeral 9 denotes a current transformer provided between the step-up transformer 4 and the rectifier 5, and 10 reads a current detected by the current transformer 9, and a control signal is sent to the thyristor controller 7 and the inverter controller 8 according to the value. Is a current detection circuit for sending a signal.

  FIG. 10A shows the current detection output of the current transformer 9 representing the change in the discharge current before and after the occurrence of arc discharge. The discharge current in period A shows a regular pulse current waveform, and the discharge is controlled by adjusting the duty. FIG. 10B shows the DC voltage Vdc obtained from the smoothing circuit 2. In the period A, the DC voltage Vdc is kept constant at 200V. In the period B, the glow discharge is changed to the arc discharge, and the current rapidly increases. FIG. 10C shows an arc detection signal P when arc discharge occurs. The inverter control unit 8 restarts the oscillation of the inverter at the same frequency in the return period D after the end of the cutoff period C. At this time, the duty of the high frequency pulse is detected from zero as shown in FIG. Gradually increase the duty before it is done. As shown in FIG. 10B, the discharge current value gradually rises in the same manner as the duty according to the change of the DC voltage Vdc, and returns to the state before the arc detection at the end of the return period D.

Japanese Patent Laid-Open No. 7-62521

  However, in the conventional power supply device that controls the voltage, current, and power to be constant and applies them to the film forming apparatus, when the same capacity of power is supplied again in a situation where the electrodes are heated, the arc discharge recurs. A thermal change occurs in the electrode, and the film forming process is not constant. For this reason, there may be a problem that the quality of film formation deteriorates or the product yield deteriorates.

  Further, in the above-described power supply apparatus disclosed in Patent Document 1, when arc discharge is detected, power to the load is cut off, and power that can be changed again is supplied, the variable power gradually increases the duty of the high-frequency pulse from zero. increase. For this reason, from the occurrence of the arc to the recovery, in addition to the period from when the arc discharge is detected until the power is cut off, a stop period and a return period are required, so that the transition to the arc discharge frequently occurs. In such a case, there is a possibility that the quality of film formation is deteriorated and the processing time is increased. In this case, since a great deal of energy is consumed between the time when arc discharge is detected and the time of return, it is desirable to suppress this energy consumption as much as possible.

  Therefore, in order to solve the above-described problems, the present invention can suppress arc discharge and can suppress energy required from detection to return of arc discharge and arc suppression in the apparatus. It aims to provide a method.

In order to achieve the above object, an AC power supply apparatus of the present invention is a power supply that supplies high-frequency AC power converted from commercial AC power to electrodes in a load , and is an AC that suppresses arc discharge generated between the electrodes. In the power supply apparatus, an AC-DC rectifier that converts the commercial AC power into first DC power and a gate control signal are used to turn on / off the gate of the first switching element that is present. A DC-DC converter that converts DC power into second DC power determined according to the load; and a first current detector that detects a feedback DC current value on the output side of the DC-DC converter; A DC-AC converter that converts the second DC power into first high-frequency AC power by turning on and off the gate of the second switching element that is present by a switching signal; and A high-frequency transformer that electrically insulates the high-frequency AC power and converts it to a second high-frequency AC power supplied to the load; a second current detector that detects an output current value on the secondary side of the high-frequency transformer; Multiplying the feedback DC current value by the feedback DC voltage value on the output side of the DC-DC converter, and subtracting the feedback power value of the multiplication result from the basic power command value as the second DC power target value And a power control means for controlling the second DC power by outputting a gate control signal for controlling on / off of the gate of the first switching element based on the power deviation value of the subtraction result; When the switching signal for controlling on / off of the gate of the switching element 2 is output to the DC-AC converter to control the first high-frequency AC power, the output current value and the arc discharge detection base are controlled. When the arc discharge is detected based on the arc reference value, a cutoff signal for cutting off the supply of high-frequency AC power to the load is generated, the output of the switching signal is stopped, and the cutoff signal is Oscillation control that outputs a switching signal in which the pulse width gradually increases from the initial pulse width to the set pulse width in order to return the supply of the high-frequency AC power to the load to the original state after a predetermined time has elapsed since generation. Means for turning on / off a gate of a switching element for outputting P-side (positive side) power in the DC-AC converter when the arc discharge is detected. When the output of the P-side switching signal to be stopped is stopped, the DC-AC converter outputs N-side (negative-side) power after the predetermined time has elapsed.
The N-side switching signal for turning on / off the gate of the switching element is output before the P-side switching signal, and when the arc discharge is detected, the N-side power is output in the DC-AC converter. When the output of the N-side switching signal for turning on / off the gate of the switching element for stopping is stopped, the P-side switching signal is output before the N-side switching signal after the predetermined time has elapsed. It is characterized by.

Preferably, the oscillation control means inputs an absolute value of a voltage value converted from an output current value by the second current detector and the arc reference value, and the absolute value and the arc reference value are input. When the absolute value is equal to or greater than the arc reference value, an arc signal is output, and a cut-off signal for cutting off the power supply to the load is output, and the load is supplied to the load for a predetermined time. An arc detecting means for outputting a reset signal after cutting off the power supply, an initial pulse width command calculating means for calculating an initial pulse width based on the cutoff signal and the reset signal, the initial pulse width, and the second pulse width A switching frequency command value of a switching signal for controlling on / off of the gate of the switching element and a dead band period are input, and within a predetermined time by the reset signal, Luz width is characterized in that it comprises a pulse width variable calculation / GATE control means for outputting a switching signal for increasing the initial pulse width to the set pulse width.

Preferably, the arc detection means inputs an output current value from the second current detector, converts a current-voltage converter that converts the output current value into a voltage value, and inputs the voltage value. A differential amplifier that outputs an output voltage value obtained by amplifying a voltage between input terminals, an absolute value converter that inputs the output voltage value, calculates an absolute value of the output voltage value, and outputs an absolute value, and the arc reference An arc reference setter for setting a value, input the absolute value and the arc reference value, compare the magnitude of the absolute value and the arc reference value, and when the absolute value is equal to or greater than the arc reference value, A comparator for outputting the arc signal; a latch / break signal generator for inputting the arc signal; holding the arc signal; and outputting a break signal; and inputting the break signal; Switching element gate is off After a predetermined time has elapsed since change in state, outputs a reset signal, characterized in that it comprises, a restart signal operation output unit for releasing said arc signal held by the latch / off signal generator.

Preferably, the initial pulse width command calculation means inputs a pulse width attenuation ratio setter for setting a pulse width attenuation ratio command value that is a ratio of a predetermined pulse width to a set pulse width, and the cutoff signal. An arc interrupt command device that outputs an arc interrupt signal based on the interrupt signal, a rate command writer that inputs the arc interrupt signal and writes the pulse width attenuation ratio command value based on the arc interrupt signal, and a pulse of the switching signal When a rate time setter that sets a rate time required for the width to change from the predetermined pulse width to a set pulse width and a reset signal from the restart signal calculation output unit are input, the rate time and the pulse width attenuation ratio A rate calculator for inputting the command value and outputting the predetermined pulse width calculated from the rate time and the pulse width attenuation ratio command value; Enter the minimum pulse width setting device that sets the minimum pulse width of the switching signal, the predetermined pulse width and the minimum pulse width, compare the size of the predetermined pulse width and the minimum pulse width, and select the larger pulse width. And a pulse width selector that selects the initial pulse width .

Preferably, the arc detection means further includes a pulse transformer between the current-voltage converter and the differential amplifier .

Preferably, the power control means calculates a new power command value by adding a swing power whose power waveform swings to the basic power command value, and calculates the feedback DC current value. The feedback DC voltage value is multiplied, the feedback DC power as the multiplication result is subtracted from the new power command value, and the gate control signal of the first switching element is calculated based on the power deviation value as the subtraction result. The second DC power is output and controlled .

Preferably, the oscillating power is set from a sine waveform, a square wave or a triangular wave, a oscillating frequency and an oscillating amplitude .

Preferably, the load is a sputtering apparatus .

Preferably, the first switching element and the second switching element are IGBTs .

The arc control method of the present invention is a power source that supplies high-frequency AC power converted from commercial AC power to electrodes in a load, and in an arc suppression method in an AC power supply device that suppresses arc discharge generated between the electrodes, An AC-DC rectification step for converting the commercial AC power into first DC power, and a gate control signal to turn on / off the gate of the first switching element, thereby converting the first DC power into the first DC power. A DC-DC conversion step for converting to a second DC power determined according to a load, and a first current value for detecting a current value in the second DC power converted by the DC-DC conversion step as a feedback DC current value. Current feedback step, multiplying the feedback direct current value by the feedback direct current voltage value in the second direct current power converted by the DC-DC conversion step. A gate control signal for subtracting the feedback power value of the multiplication result from the basic power command value as a target value of the first and turning on / off the gate of the first switching element based on the power deviation value of the subtraction result Output and control the second DC power, and the switching signal causes the gate of the second switching element to be turned on / off, thereby converting the second DC power into the first high-frequency AC power. A DC-AC converting step for converting to a high frequency transformer, a high frequency transformer converting step for electrically isolating the first high frequency AC power into a second high frequency AC power to be supplied to the load by a high frequency transformer, and the high frequency transformer. A second current detection step of detecting the output current value of the secondary side of the high-frequency transformer converted by the conversion step; and turning on / off the gate of the second switching element. When the switching signal to be controlled is output to control the first high-frequency AC power, when the arc discharge is detected based on the output current value and an arc reference value that is a detection reference of the arc discharge Generating a cut-off signal for cutting off the supply of the high-frequency AC power to the load, stopping the output of the switching signal, and after a predetermined time has elapsed since the generation of the cut-off signal, the load of the high-frequency AC power An oscillation control step for outputting a switching signal in which the pulse width gradually increases from the initial pulse width to the set pulse width in order to return the supply to the original state, and the oscillation control step detects the arc discharge. The output of the P-side switching signal for turning on / off the gate of the second switching element for outputting the P-side (positive side) power was stopped.
In this case, after the predetermined time has elapsed, an N-side switching signal for turning on / off the gate of the second switching element for outputting N-side (negative-side) power is supplied from the P-side switching signal. If the output of the N-side switching signal for turning on / off the gate of the switching element for outputting the N-side power is stopped when the arc discharge is detected first and the arc discharge is detected, the predetermined time After the elapse of time, the P-side switching signal is output before the N-side switching signal .

Preferably, the oscillation control step converts the output current value into a voltage value, compares the absolute value of the voltage value with the arc reference value, and the absolute value is equal to the arc reference value. An arc detection step of outputting an arc signal at a time or larger, outputting a cut-off signal to cut off power supply to the load, and cutting off power supply to the load for a predetermined time and then outputting a reset signal; , An initial pulse width command calculating step for calculating an initial pulse width based on the cutoff signal and the reset signal, a switching frequency of the switching signal for controlling on / off of the initial pulse width and the gate of the second switching element A command value and a dead band period are input, and the reset signal causes the pulse width to gradually increase from the initial pulse width to the set pulse width within a predetermined time. It characterized in that it comprises a pulse width variable calculation / GATE control step of outputting a quenching signal.

Preferably, the arc detection step includes a current-voltage conversion step of converting the output current value into a voltage value, a differential amplification step of amplifying the voltage value and outputting the amplified output voltage value, An absolute value conversion step of calculating the absolute value of the output voltage value and outputting the absolute value, an arc reference setting step of setting the arc reference value, comparing the magnitude of the absolute value and the arc reference value, When the absolute value is equal to or greater than the arc reference value, the comparison step of outputting the arc signal, the latch / breaking signal generation step of holding the arc signal and outputting the breaking signal, and the breaking signal And a restart signal calculation output step of outputting a reset signal and releasing the held arc signal after a predetermined time has elapsed since the gate of the second switching element changed to the OFF state. It is characterized in.

Preferably, the initial pulse width command calculation step includes a pulse width attenuation ratio setting step for setting a pulse width attenuation ratio command value that is a ratio of a predetermined pulse width to a set pulse width, and an arc based on the cutoff signal. An arc cutoff command step for outputting a cutoff signal, a rate command writing step for writing the pulse width attenuation ratio command value based on the arc cutoff signal, and a pulse width of the switching signal is changed from the predetermined pulse width to a set pulse width. A rate time setting step for setting a rate time required to perform, a rate calculation step for outputting the predetermined pulse width calculated from the rate time and a pulse width attenuation ratio command value by the reset signal, and the switching signal The minimum pulse width setting step for setting the minimum pulse width is compared with the predetermined pulse width and the minimum pulse width. And, characterized in that it comprises a pulse width selecting step of selecting whichever pulse width is greater as the initial pulse width, the.

Preferably, in the power control step, a new power command value is calculated by adding a swing power in which a power waveform swings to the basic power command value, and the feedback DC current value is calculated. The feedback DC voltage value is multiplied, the feedback DC power as the multiplication result is subtracted from the new power command value, and the gate control signal of the first switching element is calculated based on the power deviation value as the subtraction result. The second DC power is output and controlled .

  As described above, according to the present invention, the AC power supply device can suppress arc discharge as an AC power supply device used for a film forming substrate manufacturing apparatus and the like, and from detection to return of arc discharge. Can reduce the energy required.

The best mode for carrying out the present invention will be described below with reference to the drawings.
FIG. 1 is a control block diagram when the AC power supply apparatus according to the present invention is applied to a film forming substrate manufacturing apparatus. FIG. 2 is a control block diagram showing power control means in the AC power supply apparatus according to the present invention. FIG. 3 is a control block diagram showing oscillation control means in the AC power supply apparatus according to the present invention. FIG. 4 is a diagram showing a circuit example of a part of the oscillation control means in the AC power supply apparatus according to the present invention. FIG. 5 is a control block diagram showing another oscillation control means in the AC power supply according to the present invention. FIG. 6 is a control block diagram showing another power control means in the AC power supply apparatus according to the present invention. FIG. 7 is a flowchart showing a processing procedure of an arc suppression method based on arc detection in the AC power supply apparatus according to the present invention. FIG. 8 is a diagram illustrating a relationship between an arc signal, a cutoff signal, a reset signal, a switching signal, and an elapsed time in the AC power supply device according to the present invention.

〔Constitution〕
As shown in FIG. 1, the film forming substrate manufacturing apparatus 21 includes a commercial AC power supply 22, an AC power supply apparatus 23, and a load 24 such as a sputtering apparatus. The AC power supply device 23 includes an AC-DC rectifier 25, a first DC filter 26, a DC-DC converter 27, a second DC filter 28, a first current detector 29, a DC-AC converter 30, a high-frequency transformer. 31, a second current detector 32, a DC control power source 33, power control means 34, and oscillation control means 35. The AC power supply device 23 temporarily converts the three-phase AC power supplied from the commercial AC power supply 22 into DC power, further converts the DC power into AC power, and outputs the AC power to the load 24. That is, the AC power supply device 23 functions as an AC-AC converter.

  The AC-DC rectifier 25 is a three-phase full-wave rectifier circuit using a rectifier element, for example, a diode. The AC-DC rectifier 25 inputs three-phase AC power, rectifies the three-phase AC power, and supplies the DC power to the first DC filter 26. Output. The output positive terminal of the AC-DC rectifier 25 is connected to one end of the first DC filter 26, and the output negative terminal is connected to the other end of the first DC filter 24. The first DC filter 26 is a filter circuit composed of a smoothing capacitor. The DC power from the AC-DC rectifier 25 is input to smooth the DC power, and the first DC power obtained as a result is DC-DC converted. To the device 27. The first DC filter 26 has one end connected to the input positive terminal of the DC-DC converter 27 and the other end connected to the input negative terminal of the DC-DC converter 27.

  The DC-DC converter 27 is a DC-DC converter, and is a switching circuit including a semiconductor switching element, for example, an IGBT (Insulated Gate Bipolar Transistor) (hereinafter referred to as a first switching element) and a DC reactor. The conduction / cutoff between the collector and the emitter is controlled by a control signal A (hereinafter referred to as a gate control signal) A input to the gate. The IGBT collector is connected to the negative terminal of the second DC filter 28, and the emitter is connected to the negative terminal of the first DC filter 26. The DC reactor has one end connected to the positive terminal of the first DC filter 26 and the other end connected to the positive terminal of the second DC filter 28. In other words, the DC-DC converter 27 inputs the first DC power out of the DC power, turns on / off the gate of the first switching element, and converts the second DC power into the second DC power. Output to the filter 28.

  The second DC filter 28 is a filter circuit composed of a smoothing capacitor, and receives the second DC power, smoothes the second DC power, and outputs it to the DC-AC converter 30. The second DC filter 28 has one end connected to the input positive terminal of the DC-AC converter 30 and the other end connected to the input negative terminal of the DC-AC converter 30 via the first current detector 29. Is done. The first current detector 29 is a sensor that detects a current to be measured in a non-contact manner using, for example, a Hall element that is a magnetoelectric conversion element, and a feedback DC current value on the output side of the DC-DC converter 27. [C] (hereinafter, [] refers to the signal level. For example, the signal level of the signal C indicates [C]).

  The DC-AC converter 30 is an inverter circuit and includes two pairs of semiconductor switching elements (hereinafter referred to as second switching elements) facing each other, for example, IGBTs (Q1 and Q4 switches) and IGBTs (Q2 and Q3 switches). The conduction / cutoff between the collector and the emitter is controlled by a control signal D (hereinafter referred to as a switching signal) D input to the gate of the IGBT. That is, the DC-AC converter 30 repeats the on / off operation of the IGBT pairs alternately, and the waveform obtained by smoothing the second DC voltage waveform by the second DC filter 28 is a substantially rectangular AC waveform. It is a circuit for converting into a certain first high-frequency AC power. That is, the DC-AC converter 30 receives the second DC power, turns on / off the gate of the second switching element, and converts the second DC power into the first high-frequency AC power. Convert.

  The high-frequency transformer 31 is a transformer composed of a primary winding 31p and a secondary winding 31s that are electromagnetically coupled to each other. An AC voltage is input to the primary winding 31p, and the primary winding is caused by mutual electromagnetic induction. An AC voltage proportional to the turn ratio of the line 31p and the secondary winding 31s is generated in the secondary winding 31s. The primary winding 31p of the high frequency transformer 31 is connected to the emitter of the Q1 and the collector of the Q3 of the IGBT at the start of winding, and is connected to the emitter of the Q2 and the collector of the Q4 of the IGBT. The secondary winding 31 s of the high-frequency transformer 31 is connected to the load 24. That is, the high-frequency transformer 31 receives first high-frequency AC power, electrically insulates the first high-frequency AC power, and converts it into second high-frequency AC power. Similar to the first current detector 29, the second current detector 32 is a sensor that detects the current to be measured in a non-contact manner using, for example, a Hall element that is a magnetoelectric conversion element.

  In the present embodiment, the DC control power supply 33 receives a two-phase commercial power supply from the commercial AC power supply 22 and outputs a DC constant voltage, but a power supply of a system different from the commercial AC power supply 22 is used. By using it, a DC constant voltage may be output as a completely independent DC control power source.

  The power control means 34-1 is an example of the power control means 34 shown in FIG. 1, and as shown in FIG. 2, a basic power command value setter 36, a feedback power calculator 37, a subtractor 38, and a PID controller. 39 and a GATE controller 40. The basic power command value setter 36 is a setter that sets a basic power command value [F] that is a target value of the second DC power determined according to the load 24. The feedback power calculator 37 receives the feedback DC voltage value [B] and the feedback DC current value [C], multiplies the feedback DC voltage value [B] and the feedback DC current value [C], and calculates the result. Thus, the obtained feedback power value is output to the subtractor 38. The subtractor 38 receives the basic power command value [F] and the feedback power value from the basic power command value setter 36, subtracts the feedback power value from the basic power command value [F], and obtains the result based on the calculation result. The output power deviation value is output to the PID controller 39.

  The PID controller 39 receives the power deviation value, performs PID control on the power deviation value to obtain an operation amount, and outputs the operation amount to the GATE controller 40. The GATE controller 40 outputs a gate control signal A to the gate of the first switching element based on the operation amount by the PID controller 39.

  That is, the power control means 34-1 subtracts the feedback power value from the basic power command value F determined according to the load 24, and converts the gate control signal A to DC based on the power deviation value obtained as a result of the calculation. -Output to the DC converter 27, and the second DC power is controlled by the gate control signal A.

  The oscillation control means 35-1 is an example of the oscillation control means 35 shown in FIG. 1, and as shown in FIG. 3, the arc detection means 41-1, the initial pulse width command calculation means 42, and the pulse width variable calculation / gate. Control means 43 is provided. The arc detection means 41-1 includes a current-voltage converter 44, a differential amplifier 45, an absolute value converter 46, an arc reference value setting unit 47, a comparator 48, a latch / cut-off signal generator 49, and a restart signal calculation output. A container 50 is provided.

  As shown in FIG. 4, the current-voltage converter 44 includes, for example, a resistor 63 and a capacitor 64. The resistor 63 is arranged in series with the output terminal of the second current detector 32, and is parallel to the resistor 63. A capacitor 64 is disposed on the side. The current-voltage converter 44 receives the output current value [E 1] and outputs the voltage value to the differential amplifier 45. The differential amplifier 45 is a subtraction circuit, and includes, for example, resistors 65a to 65d and an operational amplifier 66 as shown in FIG. The differential amplifier 45 receives the voltage value from the current-voltage converter 44 and outputs an output voltage value [E2]. The resistors 65a to 65d have their resistance values set in advance so that the output voltage value [E2] is equal to the numerical value of the output current value [E1], and are connected to the power input line of the differential amplifier 45. ing. For example, if the output current value [E1] is 1 ampere, the output voltage value [E2] is set to 1 volt. Thus, by outputting the output voltage value [E2] from the output terminal of the differential amplifier 45, the output current value [E1] can be known.

  As shown in FIG. 3, the absolute value converter 46 receives the output voltage value [E2] from the differential amplifier 45, calculates the absolute value of the output voltage value [E2], and obtains the absolute value obtained from the calculation result. The value is output to the comparator 48. The arc reference value setting unit 47 supplies the second high frequency AC power to the load 24 via the high frequency transformer 31 by the DC-AC converter 30 and becomes an arc reference value [G ] Is a setting device for setting. The comparator 48 inputs the absolute value and the arc reference value [G] from the arc reference value setter 47, compares the absolute value with the arc reference value [G], and the absolute value is the arc reference value [ When it is equal to or greater than G], an arc signal is output to the latch / break signal generator 49.

  The latch / shutoff signal generator 49 receives an arc signal, and receives a shutoff signal L latched by the arc signal as a restart signal computation output unit 50, an initial pulse width command computation unit 42, and a pulse width variable computation / GATE control unit 43. Output to. The restart signal calculation output unit 50 inputs the shut-off signal L. After the predetermined time has elapsed after the shut-off signal L is input to the restart signal calculation output unit 50, the latch of the latch / shut-off signal generator 49 is released. The reset signal M is output to the latch / cut-off signal generator 49.

  The initial pulse width command calculating means 42 includes a pulse width attenuation ratio setting device 51, an arc interruption command device 52, a rate command writing device 53, a rate time setting device 54, a rate operation device 55, a minimum pulse width setting device 56, and an initial pulse width. A selector 57 is provided. The pulse width attenuation ratio setting unit 51 has a pulse width (hereinafter referred to as “original pulse width”) [H] corresponding to the reciprocal of the switching frequency of the second switching element in a steady state and a dead band period [DT] (or This is a setting device for setting a pulse width attenuation ratio command value K which is a ratio of a predetermined pulse width [N] to a set pulse width [HA] including “dead time”. Here, the dead band period [DT] is a period for surely turning off the second switching element when the P-side and N-side switching signals D are switched. Further, the set pulse width [HA] is a value obtained by subtracting the dead band period [DT] from the original pulse width [H].

  The arc interruption commander 52 receives the interruption signal L from the latch / interruption signal generator 49 and outputs the arc interruption signal to the rate instruction writer 53. The rate command writer 53 is a writer that receives an arc cutoff signal from the arc cutoff commander 52 and writes a pulse width attenuation ratio K by the pulse width attenuation ratio setting unit 51. The rate time setter 54 is a setter for setting a rate time [J] as a time required for the pulse width of the switching signal D to gradually increase from the predetermined pulse width [N] to the set pulse width [HA]. is there. The rate calculator 55 releases the cutoff signal L by the reset signal M, and outputs the predetermined pulse width N calculated to the initial pulse width selector 57 based on the rate time [J] and the pulse width attenuation ratio [K]. To do.

  The minimum pulse width setting device 56 is a setting device for setting the minimum pulse width [I] of the switching signal D. The minimum pulse width [I] is determined in view of the characteristics of the second switching element, the occurrence of arcing, and the like. If the minimum pulse width [I] is too narrow, the second switching element may be destroyed, discharge may not occur, and the time until the power source changes from the ON state to the normal discharge state may be lost. This is because it takes too much and the production efficiency of the substrate may be lowered. For example, in IGBT, the minimum pulse width [I] is 2 microseconds.

  The initial pulse width selector 57 inputs the minimum pulse width [I] from the minimum pulse width setter 56 and the predetermined pulse width [N] from the rate calculator 55, and the minimum pulse width [I] and the predetermined pulse width [N]. ], And the larger pulse width is output to the pulse width variable calculation means 43 as the initial pulse width [P]. That is, the initial pulse width [P] corresponds to a ratio signal for controlling the set pulse width [HA]. If the initial pulse width [P] is, for example, an output equivalent to 60% of the set pulse width [HA], it is restarted at a pulse width equivalent to 60%, and after the rate time [J] has elapsed, % Signal.

  The pulse width variable calculation / GATE control means 43 includes a switching frequency command setter 58, a dead band setter 59, a switching pulse width generator 60, a pulse width variable calculator 61, and a GATE controller 62. The switching frequency command value setter 58 is a setter that sets the switching frequency command value of the switching signal D that turns on / off the gate of the second switching element. The dead band setting unit 59 sets a dead band period [DT] provided to prevent a short circuit between the P side and the N side of the switching signal D when switching the gate of the second switching element. It is a setting device.

  The switching pulse width generator 60 inputs the switching frequency command value by the switching frequency command value setting unit 58 and the dead band period [DT] by the dead band setting unit 59, and the original pulse width [H] from the switching frequency command value. , Subtract the dead band period [DT] from the original pulse width [H], and output the set pulse width [HA] obtained as a result of the calculation to the pulse width variable calculator 61. The variable pulse width calculator 61 receives the initial pulse width [P] from the initial pulse width selector 57 and the set pulse width [HA] from the switching pulse width generator 60. When the power supply to the load 24 is interrupted by the cutoff signal L and the power supply is restored by the reset signal M from the restart signal computation output unit 50 after a predetermined time t1 has elapsed, the variable pulse width computing unit 61 The pulse width of the switching signal D starts from the initial pulse width [P], and gradually increases and changes until the rate time [J] by the rate time setting unit 54 elapses and reaches the set pulse width [HA]. The pulse width train is output to the gate controller 62. The gate controller 62 receives the pulse width train and outputs a switching signal D based on the pulse width train to the gate of the second switching element.

  That is, the oscillation control means 35-1 calculates the original value calculated from the output frequency [E 1] and the switching frequency by the switching frequency command setter 58 of the switching signal D for controlling the on / off of the gate of the second switching element. Based on the pulse width [H], the arc reference value [G] as the arc discharge detection reference, and the initial pulse width [P] when the switching signal D is restarted, the switching signal D is DC-AC converted. The first high frequency AC power is controlled by the switching signal D. In other words, the oscillation control means 35-1 switches the switching so that the power supply is restored after a predetermined time after the power supply to the load 24 is cut off for a predetermined time based on the detection of the arc signal by the arc discharge. The power is controlled so that the pulse width of the signal D gradually increases from the initial pulse width [P] to the set pulse width [HA].

  Next, another oscillation control means 35-2 in the AC power supply apparatus according to the present invention will be described. FIG. 5 is a control block diagram showing another oscillation control means in the AC power supply according to the present invention. 5 shows the same functions as those in FIG. 3 with the same reference numerals. As shown in FIG. 5, the other oscillation control means 35-2 is obtained by adding a pulse transformer 67 to the oscillation control means 35-1. That is, the oscillation control means 35-2 arranges the pulse transformer 67 between the current-voltage converter 44 and the differential amplifier 45 of the oscillation control means 35-1.

  Next, another power control means 34-2 in the AC power supply apparatus according to the present invention will be described. FIG. 6 is a control block diagram showing another power control means in the AC power supply apparatus according to the present invention. 6 shows the same functions as those in FIG. 2 with the same reference numerals. As shown in FIG. 6, the other power control unit 34-2 is obtained by adding a swing power control unit 68, an adder / subtractor 73, and a power command calculator 74 to the power control unit 34-1.

  The swing power control means 68 includes a swing level setter 69, an adder 70, a swing value / swing frequency setter 71, and a swing waveform selector 72. The swing level setter 69 is a setter for setting a direct current level of a swing power command to be described later. The oscillation value / oscillation frequency setter 71 adds a basic waveform of power (hereinafter referred to as oscillation power) to be added to the basic power command value [F] to oscillation (hereinafter referred to as basic oscillation waveform). ) Is a setting device for setting a rocking amplitude Z of a basic rocking waveform as a rocking value and a rocking cycle Y that is the reciprocal of the rocking frequency. The swing waveform selector 72 inputs the swing amplitude Z and the swing cycle Y, and swings according to the swing amplitude Z and the swing cycle Y depending on the power capacity of the load 24 and / or the state of occurrence of arc discharge. It is a selector that selects any one of a sine wave, a rectangular wave, and a triangular wave as a waveform shape of power.

  The adder 70 inputs the DC level of the oscillating power and the pulse characteristic value composed of the specific shape of the oscillation amplitude Z, the oscillation period Y, and the basic oscillation waveform, and these DC level and pulse characteristic value are input. The included pulse characteristic information is output to the adder / subtractor 73. The adder / subtractor 73 receives the basic power command value [F] and the pulse characteristic information from the basic power command value setter 36, adds or subtracts the basic power command value [F] and the pulse characteristic information, and combines the combined power. The command value is output to the power command calculator 74. The power command calculator 74 receives the power command value, and outputs a new power command value to the subtractor 38 based on the power command value. The other configurations are the same as those obtained by replacing the basic power command value [F] in the case of the power control means 34-1 shown in FIG. .

[Arc suppression method]
Next, an arc suppression method in the AC power supply apparatus according to the present invention will be described. The arc suppression method in the AC power supply device 23 is as follows. First, an AC-DC rectification step for converting a commercial AC power source into first DC power, and the first DC power from the gate of the first switching element. A DC-DC conversion step for performing on / off operation to convert the second DC power determined according to the load 24, and a gate control signal for controlling on / off of the gate of the first switching element; A power control process for controlling the second DC power, and a DC-AC that inputs the second DC power, turns on / off the gate of the second switching element, and converts the second DC power into the first high-frequency AC power. Based on the conversion process and the detection of the arc signal due to arc discharge, a cut-off signal L for cutting off the power supply is output, and after the power supply to the load 24 is cut off for a predetermined time, a reset signal M is output, The pulse width of the switching signal for on / off control of the gate of the second switching element is set to the initial pulse width [P] so that the power supply is restored to the original state after a certain time after the output signal M is output. And an oscillation control step of gradually increasing the set pulse width [HA] to power control.

  Further, the power control step includes a basic power command value setting step for setting a basic power command value F as a target value of the second DC power, a feedback power value calculation step for calculating the feedback power value, and a basic power command. A power deviation value calculating step of calculating a power deviation value obtained by subtracting the feedback power value from the value F and calculating the result, and on / off control of the gate of the first switching element based on the power deviation value And outputting a gate control signal A to control the second DC power.

  In addition, the oscillation control process detects an output current value [E1] obtained from the second high-frequency AC power obtained by electrically isolating the first high-frequency AC power via the high-frequency transformer 31. A current-voltage conversion step for converting the output current value [E1] into a voltage value, and amplifying the voltage between the two input terminals that receives the voltage value and uses the voltage value as an output voltage value [ E2], a differential amplifying step for calculating the absolute value of the output voltage value [E2], and an absolute value calculating step for outputting an absolute value based on the result of the calculation, and the absolute value and arc discharge A comparison step of comparing the magnitude with an arc reference value [G] as a detection reference; an arc signal output step of outputting an arc signal when the absolute value is equal to or greater than the arc reference value [G]; Input arc signal, arc signal And a step of generating a latch / interruptible signal that outputs the interrupt signal L based on the arc signal, and after the interrupt signal L is input and the gate of the second switching element is turned off by the interrupt signal L After a predetermined time has elapsed, the restart signal calculation output step for releasing the held arc signal and outputting the reset signal M, the reset signal M being input, the rate time [J], and the pulse width attenuation ratio A rate calculating step for outputting a predetermined pulse width [n] calculated from [K], a predetermined pulse width [N] and a minimum pulse width [I] are input, and the predetermined pulse width [N] and the minimum pulse width are input. The initial pulse width selection step of comparing the width [I] with the magnitude of the width [I] and selecting the larger pulse width as the initial pulse width [P], and the switching signal D for controlling the on / off of the gate of the second switching element switch Switching which calculates the pulse width of the switching signal D based on the set pulse width [HA] based on the switching frequency command value and the dead band period DT and the initial pulse width [P] and is restarted by the reset signal M A pulse width variable calculation / GATE control step for outputting the signal D.

  Further, the switching signal at the time of restarting is the switching signal D composed of the P side and the N side, and the switching of either the N side or the P side opposite to the P side or the N side for detecting the arc starts.

  Furthermore, a new power command value, a feedback DC current value [C], and a feedback DC voltage value [C] obtained by adding a swing power whose power waveform changes in a swinging manner to the basic power command value [F]. B] is input, the feedback DC current value [C] and the feedback DC voltage value [B] are multiplied from the new power command value, and the obtained feedback power value is subtracted. Based on the generated power deviation value, a gate control signal A for controlling on / off of the gate of the first switching element is output to control the second DC power.

  FIG. 7 is a flowchart showing a processing procedure of an arc suppression method based on arc detection in the AC power supply apparatus according to the present invention. As shown in FIG. 7, the oscillation control process electrically isolates the first high-frequency AC power via the high-frequency transformer 31, and outputs the output current value [E1] obtained from the second high-frequency AC power. An output current value detecting step (S-1) to detect, a current-voltage converting step for converting the output current value [E1] into a voltage value, and the voltage between both input terminals that receives the voltage value and uses it as the voltage value Differential amplification step of outputting the output voltage value [E2] which is an amplified voltage, and calculating the absolute value of the output voltage value [E2], and outputting the absolute value obtained from the result of the calculation The absolute value calculation step (S-2), the comparison step (S-3) for comparing the magnitude of the absolute value and the arc reference value [G] as the arc discharge detection reference, and the absolute value is the arc reference value [G ] Is greater than or equal to (S-4), an arc signal holding step (S-5) for holding an arc signal, and a latch / cut-off signal for inputting an arc signal, holding (latching) the arc signal, and outputting a cut-off signal L A generation step (S-5), a restart signal calculation output step (S-7) for outputting the reset signal M after a predetermined time has elapsed after the interruption signal L is input, and an arc signal for the switching signal D. The old data is reset (erased), and the predetermined pulse width [N] calculated from the predetermined rate time [J] and the pulse width attenuation ratio [K] is output to the initial pulse width selector 57, and at the same time, the rate calculator 55, resetting 55 (S-8), setting the minimum pulse width [I], outputting the minimum pulse width [I] to the initial pulse width selector 57 (S-9), and a predetermined pulse width [ N] and minimum pulse width [I] (S-10), the initial pulse width selection step (S-11A and S-11B) for selecting the larger pulse width as the initial pulse width [P], the switching frequency of the switching signal D, A step (S-12) of setting a dead band period DT, outputting a set pulse width [HA] calculated from the switching frequency and the dead band period DT to the pulse width variable calculator 59, and a set pulse width [HA And a pulse width variable calculation step (S-13) for calculating the pulse width of the switching signal D based on the initial pulse width [P] and the rate time [J]. Thereby, arc discharge in the AC power supply device 23 can be suppressed.

  Further, a feedback power value obtained by multiplying the feedback DC current value [C] and the feedback DC voltage value [B] is subtracted from the basic power command value [F], and the power obtained by the calculation result is obtained. A step of outputting a gate control signal A for controlling on / off of the gate of the first switching element based on the deviation value and controlling the second DC power is provided.

  Furthermore, the feedback DC current value [C] and the feedback DC voltage value [B] are obtained from a new power command value obtained by adding a swaying power whose power waveform changes dynamically to the basic power command value [F]. The gate control signal A for controlling on / off of the gate of the first switching element based on the obtained power deviation value is output based on the result of the calculation, and the feedback power value obtained by multiplying A step of controlling DC power. Thereby, the arc discharge in the AC power supply device 23 can be further suppressed.

[Operation]
Next, the operation of the AC power supply device 23 according to the present invention will be described.
First, the overall operation of the AC power supply device 23 will be described. When the commercial AC power supply 22 is input to the AC-DC rectifier 25, the AC-DC rectifier 25 rectifies the AC power into the DC power and outputs the first DC power. When the first DC power is input to the DC-DC converter 27, the gate of the first switching element existing in the DC-DC converter 27 is controlled to be turned on / off by the gate control signal A by the power control means 34, The output voltage of the DC-DC converter 27 is controlled to be constant and the output power is controlled to output the second DC power.

  When the second DC power is input to the DC-AC converter 30, the gate of the second switching element inherent in the DC-AC converter 30 is switched at a high speed by the switching signal D from the oscillation control means 35, and the high-frequency AC is switched. It reverse-converts into the 1st high frequency alternating current power used as electric power. When the first high-frequency AC power is input to the high-frequency transformer 31, the second high-frequency AC power that is electrically insulated from the commercial AC power supply 22 is supplied to the load 24.

  Next, the operation of the power control unit 34-1 will be described. The power control means 34-1 receives the feedback DC voltage value [B] and the feedback DC current value [C] from the first current detector 29 as shown in FIGS. A gate control signal A for operating the first switching element is output to the DC-DC converter 27 based on the basic power command value [F] by the setting device 36. Here, the basic power command value [F] is determined by parameters such as the size of the load 24 and the production efficiency.

  When the feedback DC voltage value [B] and the feedback DC current value [C] from the first current detector 29 are input to the feedback power calculator 37, the feedback DC voltage value [B] and the feedback DC current value [C] And the obtained feedback power value is output to the subtractor 38. When the feedback power value and the basic power command value [F] are input to the subtractor 38, the feedback power value is subtracted from the basic power command value [F], and the power deviation value obtained as a result of the calculation is calculated by the PID controller 39. Output to.

  When the power deviation value is input to the PID controller 39, the PID controller 39 causes the PID controller 39 to operate in proportion to the power deviation value, and to change the input value in proportion to the integral of the power deviation value, and the power deviation value The control is performed in combination with a differential operation for changing the input value in proportion to the differential of, and the manipulated variable is output to the GATE controller 40. In this case, only the PI operation may be controlled instead of the PID operation. The GATE controller 40 outputs a gate control signal A to the gate of the first switching element based on the operation amount by the PID controller 39. That is, when the power deviation value increases, control is performed so that the ON operation time of the gate control signal A becomes longer, and when the power deviation value decreases, control is performed so that the ON operation time of the gate control signal A becomes shorter. Thereby, the power control means 34-1 can control the input DC power to a constant DC power.

  Next, the operation of the oscillation control means 35-1 will be described. FIG. 8 is a diagram showing the relationship between the arc signal, the cutoff signal L, the reset signal M, the switching signal D, and the elapsed time in the AC power supply according to the present invention. FIG. 8A is a diagram illustrating the relationship between the arc signal and the elapsed time, where the horizontal axis indicates the elapsed time t and the vertical axis indicates the arc signal. Point Q indicates the point in time when the arc signal is generated. FIG. 8B is a diagram illustrating the relationship between the cutoff signal L and the reset signal M and the elapsed time, where the horizontal axis indicates the elapsed time t, and the vertical axis indicates the cutoff signal and the reset signal. The time t1 indicates a predetermined time from when the cutoff signal L is output in several microseconds to 1 millisecond, for example, until the reset signal M is output. Point R indicates a point in time when the blocking signal L is output, and point S indicates a point in time when the reset signal M is output.

  FIG. 8C is a diagram showing the relationship between the voltage waveform on the P side (switches Q1 and Q4) of the switching signal D and the elapsed time, the horizontal axis is the elapsed time t, and the vertical axis is on / off. Each signal is shown. Time t3 indicates the power-off time on the P side. Point T indicates the time when the switching signal D is turned off at the time when the blocking signal L is generated. Point U indicates a point at which the P side is turned on immediately after the switching signal D on the N side is turned on from the point S. Point V indicates a point where the pulse width returns to the set pulse width [HA] after a predetermined time [J] has elapsed after the P-side switching signal D is turned on. FIG. 8D is a diagram showing the relationship between the voltage waveform on the N side (switches Q2 and Q3) of the switching signal D and the elapsed time, the horizontal axis is the elapsed time t, and the vertical axis is the switching signal. The on / off signals to be performed are respectively shown. DT is provided on the N side as well as on the P side. Time t2 indicates the power-off time on the N side. A point W indicates that the reset signal M is output and the N-side switching signal D is turned on. Point X indicates a point at which the pulse returns to the set pulse width [HA] after a lapse of a certain time [J], for example, 1 millisecond after the switching signal D is turned on.

  When the output current value [E1] from the second current detector 32 is input to the arc detection means (A) 41-1, the voltage value is converted into a differential amplifier 45 by the current-voltage converter 44 of the arc detection means 41-1. Output to. When the voltage value is input to the differential amplifier 45, the output voltage value [E2] obtained by amplifying the voltage value by the differential amplifier 45 is output to the absolute value converter 46. As a result, common mode noise can be reduced when electrical noise is superimposed on the voltage on the high voltage side with respect to the ground of the wiring path.

  When the output voltage value [E2] is input to the absolute value converter 46, the absolute value of the output voltage value [E2] is output to the comparator 48. When the absolute value and the arc reference value [G] by the arc reference value setting unit 47 are input to the comparator 48, the absolute value and the arc reference value [G] are compared with each other, and the absolute value obtained from the result of the operation is compared. When is equal to or greater than the arc reference value [G], an arc signal is output to the latch and interrupt signal generator 49. That is, when an arc signal is generated during film formation, the arc signal changes from a HIGH signal to a LOW signal at a point Q as shown in FIG. 8A, for example.

  When the arc signal is input to the latch and cutoff signal generator 49, the latch and cutoff signal generator 49 outputs the latched cutoff signal L to the restart signal calculation output unit 50 and the initial pulse width calculation means 42. In this case, the cutoff signal L is output at a point R as shown in FIG. In other words, due to the delay of the signal processing time by the latch and shut-off signal generator 49, the current state of the load 24 is changed from HIGH to the shut-off state LOW at a point R slightly delayed from the point Q at which the arc signal is output. In addition, a cutoff signal L is output. When the cutoff signal L is output, as shown in FIG. 8C, for example, among the switching signals D, for example, the P-side switching signal D is initially turned off.

  When the shut-off signal L is input to the restart signal calculation output unit 50, a timer built in the restart signal calculation output unit 50 is activated, and after a predetermined time t1, the timer is turned off and the reset signal M is latched. And output to the interruption signal generator 49. That is, the cutoff signal L is changed from LOW to HIGH at the point S and output by the reset signal M as shown in FIG. When the reset signal M is output, as shown in FIG. 8D, the switching signal D is set to rise from a pulse signal (point W) on the N side and closest to the reset signal M. As a result, the power to the load 24 is stopped by the cutoff signal L during the times t2 and t3 by the switching signal D on the P side and the N side, respectively.

  In the above description, when the cutoff signal L is output while the P-side switching signal D is ON, the switching signal D started by the reset signal M is first on the N side and then on the P side. On the contrary, when the cutoff signal L is output, if the switching signal D on the N side is in the ON state, the switching signal D started by the reset signal M is first on the P side and subsequently on the N side. Set to be on the side. That is, the switching signal D consisting of the P side and the N side to be restarted by the reset signal M starts switching on the N side or the P side opposite to the P side or the N side for detecting the arc. . In this case, when switching starts on the same P side or N side as the polarity when the arc is detected, magnetic saturation occurs in the high-frequency transformer 31 and the resistance value decreases. As a result, the current increases and an arc may occur. That is, by starting switching on the P side or N side of the opposite polarity, magnetic saturation of the high-frequency transformer 31 can be prevented, and as a result, generation of arc can be suppressed. Further, the arc can be prevented from increasing due to the plasma. That is, the high-frequency transformer 31 does not saturate when the first high-frequency AC power output from the DC-AC converter 30 is converted into the second high-frequency AC power. The second high-frequency AC power corresponding to the signal can be supplied to the load 24.

  When the interruption signal L is input to the initial pulse width calculation means 42, the interruption signal L is input to the arc interruption command device 52 in the initial pulse width calculation means 42 and the arc interruption signal is output to the rate command writer 53. When the arc interruption signal is input to the rate command writer 53, the pulse width attenuation ratio [K] by the pulse width attenuation ratio setter 51 is written to the rate command writer 53. The pulse width attenuation ratio [K] is information for making it possible to vary the pulse width of the switching signal D at the time of restart so as to suppress arc discharge when arc discharge occurs during film formation. . The old data of the switching signal D is reset (erased) by the arc signal, and the predetermined pulse width [N] is calculated from the rate time [J] by the rate time setter 54 and the pulse width attenuation ratio [K] by the rate command writer 53. ] Is output to the initial pulse width selector 57, and at the same time, the rate calculator 55 of the initial pulse width calculator 42 is reset by the reset signal M.

  When the minimum pulse width [I] and the predetermined pulse width [N] by the minimum pulse width setter 56 are input to the initial pulse width selector 57, the magnitudes of the minimum pulse width [I] and the predetermined pulse width [N] are compared. Depending on the calculation result, the larger initial pulse width [P] to be obtained is selected, and the initial pulse width [P] is output to the variable pulse width calculation / GATE control means 43. The initial pulse width [P], and the set pulse width [HA] calculated from the switching frequency command value by the switching frequency command setter 58 and the deadband period DT by the deadband setter 59 are the pulse width variable calculation / GATE. When input to the variable pulse width calculator 61 of the control means 43, as shown in FIG. 8, the variable pulse width calculator 61 causes the switching signal D to be sent to the initial pulse width [P at the time of restart within the rate time [J]. ] To the set pulse width [HA] gradually increasing, and a pulse width train is output to the GATE controller 62. When the pulse width train is input to the GATE controller 62, the switching signal D for controlling the second switching element is output to the DC-AC converter 30 via the drive circuit (not shown) based on the pulse width train. To do.

  Next, the operation of the power control unit 34-2 will be described. The power control unit 34-2 is different from the power control unit 34-1 in the function of setting the power command value. The power control means 34-2 uses the swing value / oscillation frequency setter 71 to change the swing amplitude Z of the basic swing waveform added to the basic power command value [F] and the swing that is the reciprocal of the swing frequency. A cycle Y is set. Next, the oscillation waveform selector 72 changes the oscillation amplitude Z, the oscillation cycle Y, and the shape of the basic oscillation waveform into a sine wave, depending on the power capacity of the load 24 and / or the state of occurrence of arc discharge. Select either rectangular or triangular waveform. Outputs pulse characteristic information by adding the DC swing level by the swing level setter and the pulse characteristic value consisting of the swing amplitude Z, swing period Y, and the basic shape of the basic swing waveform, and the basic power command The basic power command value [F] by the value setter 36 and the pulse characteristic information are synthesized, and the obtained power command value is output to the subtractor 38 as a new power command value. Since the power control means 34-2 is replaced by a new power command value instead of the basic power command value [F] by the basic power command value setting unit 36 in the power control means 34-1, the following power A description of the control is omitted.

  Next, the operation of the other oscillation control means 35-2 will be described. The secondary side 67s of the pulse transformer 67 is a secondary side winding of the pulse transformer 67, and the winding ratio is, for example, 1: 1 with respect to the primary side winding 67p. Thereby, the AC power supply device 23 having the pulse transformer 67 can improve the input / output insulation of the signal for detecting the arc signal as compared with the AC power supply device not having the pulse transformer 67. Furthermore, the transmission delay of the signal can be reduced as compared with an insulation method employing a photocoupler.

  As described above, when arc discharge occurs, the supply of power is cut off by the cut-off signal L, and the reset signal M is output after a predetermined time t1 has elapsed. After a predetermined time has passed since the reset signal M was output, the pulse width of the switching signal D for controlling the high-frequency AC power supplied to the load 24 is gradually increased from the initial pulse width [P] to the set pulse width [HA]. Power control. Since the switching signal D does not start from the zero pulse width but starts from the initial pulse width [P], the time from the detection of the arc discharge to the return can be shortened. Thereby, the energy until it returns from arc discharge can be suppressed. Further, the switching signal D composed of the P side and the N side that is restarted by the reset signal M starts switching of the N side or the P side opposite to the P side or the N side for detecting the arc. I made it. Thereby, magnetic saturation of the high frequency transformer 31 can be prevented. That is, in the high-frequency transformer 31, it is possible to prevent the resistance from being reduced, so that the current does not increase. Therefore, the occurrence of arc discharge can be suppressed.

  Further, by arranging the pulse transformer 65 between the current-voltage converter 44 and the differential amplifier 45, the input / output of a signal for detecting an arc signal as compared with an AC power supply device having no pulse transformer 67 is provided. It is possible to improve the insulation. Furthermore, the transmission delay of the signal for detecting the arc signal can be reduced as compared with the insulation method employing the photocoupler.

It is a control block diagram at the time of applying the alternating current power supply device which concerns on this invention to the board | substrate manufacturing apparatus for film-forming. It is a control block diagram which shows the electric power control means in the alternating current power supply device which concerns on this invention. It is a control block diagram which shows the oscillation control means in the alternating current power supply device which concerns on this invention. It is a figure which shows the example of a circuit of a part of oscillation control means in the alternating current power supply device which concerns on this invention. It is a control block diagram which shows the other oscillation control means in the alternating current power supply device which concerns on this invention. It is a control block diagram which shows the other electric power control means in the alternating current power supply device which concerns on this invention. It is a flowchart figure which shows the process sequence of the arc suppression method based on the detection of the arc in the alternating current power supply device which concerns on this invention. It is a figure which shows the relationship between the arc signal, interruption | blocking signal, a reset signal, and a switching signal, and elapsed time in the alternating current power supply device which concerns on this invention. It is a figure which shows the apparatus structure in a prior art. It is a figure which shows the signal waveform of each part of the apparatus before and after the arc discharge of the apparatus in a prior art generate | occur | produced.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 DC control part 2 Smoothing circuit 3 Inverter switching part 4 Step-up transformer 5 Rectification part 6 Processing apparatus main body 7 Thyristor control part 8 Inverter control part 9 Current transformer 10 Current detection circuit 21 Film-forming substrate manufacturing apparatus 22 Commercial AC power supply 23 AC power supply Device 24 Load 25 AC-DC Rectifier 26 First DC Filter 27 DC-DC Converter 28 Second DC Filter 29 First Current Detector 30 DC-AC Converter 31 High Frequency Transformer 32 Second Current Detector 33 DC control power supplies 34-1 and 34-2 Power control means 35-1 and 35-2 Oscillation control means 36 Basic power command value setter 37 Feedback power calculator 38 Subtractor 39 PID controller 40 GATE controller 41-1 , 41-2 Arc detection means 42 Initial pulse width command calculation means 43 Pulse width variable calculation / GATE control means 44 Current-voltage converter 45 Differential amplifier 46 Absolute value converter 47 Arc reference value setter 48 Comparator 49 Latch / cutoff signal generator 50 Restart signal calculation output unit 51 Pulse width attenuation ratio setter 52 Arc cutoff commander 53 Rate command writer 54 Rate time setter 55 Rate calculator 56 Minimum pulse width setter 57 Initial pulse width selector 58 Switching frequency command setter 59 Deadband setter 60 Switching pulse width generator 61 Pulse width variable calculator 62 GATE controller 63 Resistor 64 Smoothing capacitor 65 Resistor 66 Operational amplifier 67 Pulse transformer 68 Oscillation power control means 69 Oscillation level setter 70 Adder 71 Oscillation value / oscillation frequency setter 72 Oscillation waveform selector 73 Adder / Subtractor 74 Power command calculator A Gate control signal B Feedback DC current signal C Feedback DC voltage No. D switching signal E1 output current signal E2 output voltage signal F basic power command signal G arc reference signal H original pulse width signal HA set pulse width signal P initial pulse width signal Y swinging periodic signal Z swinging amplitude signal

Claims (14)

A power supply for supplying high-frequency AC power converted from commercial AC power to electrodes in a load, wherein the AC power supply device suppresses arc discharge generated between the electrodes .
An AC-DC rectifier that converts the commercial AC power into first DC power;
A DC-DC converter that converts the first DC power into a second DC power determined according to the load by turning on / off the gate of the first switching element that is present according to a gate control signal. When,
A first current detector for detecting a feedback direct current value on the output side of the DC-DC converter;
A DC-AC converter that turns on and off the gate of the second switching element that is present by a switching signal to convert the second DC power into first high-frequency AC power;
A high-frequency transformer that electrically insulates the first high-frequency AC power and converts it to a second high-frequency AC power supplied to the load;
A second current detector for detecting an output current value on the secondary side of the high-frequency transformer;
Multiplying the feedback direct current value by the feedback direct current voltage value on the output side of the DC-DC converter, and using the basic power command value as the target value of the second direct current power, the feedback power value of the multiplication result is obtained. Power control means for subtracting and outputting a gate control signal for controlling on / off of the gate of the first switching element based on the power deviation value of the subtraction result to control the second DC power;
When the first high-frequency AC power is controlled by outputting a switching signal for controlling on / off of the gate of the second switching element to the DC-AC converter, the output current value and the arc discharge When the arc discharge is detected based on an arc reference value that is a detection reference, a cut-off signal for cutting off the supply of high-frequency AC power to the load is generated, the output of the switching signal is stopped, and the cut-off is performed After a predetermined time has elapsed since the signal was generated, a switching signal in which the pulse width gradually increases from the initial pulse width to the set pulse width is output in order to restore the supply of the high-frequency AC power to the load. Oscillation control means;
With
The oscillation control means detects a P-side switching signal for turning on / off a gate of a switching element for outputting P-side (positive side) power in the DC-AC converter when the arc discharge is detected. When output is stopped, an N-side switching signal for turning on / off a gate of a switching element for outputting N-side (negative side) power in the DC-AC converter after the predetermined time has elapsed. Is output prior to the P-side switching signal, and when the arc discharge is detected, the N-side is operated to turn on / off the gate of the switching element for outputting the N-side power in the DC-AC converter. When the output of the switching signal is stopped, the P-side switching signal is output before the N-side switching signal after the predetermined time has elapsed. AC power supply and wherein the that.   The oscillation control means includes
  The absolute value of the voltage value converted from the output current value by the second current detector and the arc reference value are input, the magnitudes of the absolute value and the arc reference value are compared, and the absolute value is the arc value. When it is equal to or larger than a reference value, an arc signal is output, a cut-off signal for cutting off the power supply to the load is output, a power supply to the load is cut off for a predetermined time, and then a reset signal is output. Arc detecting means;
  An initial pulse width command calculating means for calculating an initial pulse width based on the blocking signal and the reset signal;
  The initial pulse width, a switching frequency command value of a switching signal for controlling on / off of the gate of the second switching element, and a dead band period are input, and the pulse width is set within a predetermined time by the reset signal. A pulse width variable calculation / GATE control means for outputting a switching signal that gradually increases from an initial pulse width to a set pulse width;
The AC power supply device according to claim 1, comprising: The arc detecting means includes
A current-voltage converter that inputs an output current value from the second current detector and converts the output current value into a voltage value;
A differential amplifier that inputs the voltage value and outputs an output voltage value obtained by amplifying the voltage between the input terminals;
An absolute value converter that inputs the output voltage value, calculates an absolute value of the output voltage value, and outputs an absolute value;
An arc reference setting device for setting the arc reference value;
A comparator that inputs the absolute value and the arc reference value, compares the magnitude of the absolute value and the arc reference value, and outputs the arc signal when the absolute value is equal to or greater than the arc reference value;
A latch / break signal generator for inputting the arc signal, holding the arc signal, and outputting a break signal;
The interruption signal is input, and after a predetermined time has elapsed since the gate of the second switching element is turned off by the interruption signal, a reset signal is output, and the arc held by the latch / interruption signal generator A restart signal calculation output device for releasing the signal;
The AC power supply device according to claim 2 , comprising: The initial pulse width command calculation means includes:
A pulse width attenuation ratio setting device for setting a pulse width attenuation ratio command value that is a ratio of a predetermined pulse width to a set pulse width;
An arc interrupt command device that inputs the interrupt signal and outputs an arc interrupt signal based on the interrupt signal;
A rate command writer for inputting the arc cutoff signal and writing the pulse width attenuation ratio command value based on the arc cutoff signal;
A rate time setting device for setting a rate time required for the pulse width of the switching signal to change from the predetermined pulse width to the set pulse width;
When a reset signal is input by the restart signal calculation output device, the rate time and pulse width attenuation ratio command value are input, and the predetermined pulse width calculated from the rate time and pulse width attenuation ratio command value is output. A rate calculator,
A minimum pulse width setting device for setting the minimum pulse width of the switching signal;
A pulse width selector that inputs the predetermined pulse width and the minimum pulse width, compares the predetermined pulse width and the minimum pulse width, and selects the larger pulse width as the initial pulse width;
The AC power supply device according to claim 2, further comprising: The arc detecting means includes
4. The AC power supply apparatus according to claim 3 , further comprising a pulse transformer between the current-voltage converter and the differential amplifier . The power control means includes
A new power command value is calculated by adding a swing power whose power waveform changes in a swinging manner to the basic power command value, and the feedback DC current value is multiplied by the feedback DC voltage value. The feedback DC power that is the multiplication result is subtracted from the power command value, and the second DC power is controlled by outputting the gate control signal of the first switching element based on the power deviation value that is the subtraction result. The AC power supply device according to any one of claims 1 to 5 , wherein the AC power supply device according to any one of claims 1 to 5 is provided. The AC power supply device according to claim 6 , wherein the oscillating power is set from a power waveform consisting of a sine waveform, a square wave or a triangular wave, an oscillation frequency and an oscillation amplitude . The AC power supply apparatus according to any one of claims 1 to 7, wherein the load is a sputtering apparatus. The first switching element and the second switching element are IGBTs.
The AC power supply device according to any one of claims 1 to 8, characterized by:   In a power supply for supplying high-frequency AC power converted from commercial AC power to an electrode in a load, in an arc suppression method in an AC power supply apparatus that suppresses arc discharge generated between the electrodes,
  AC-DC rectification step for converting the commercial AC power into first DC power;
  A DC-DC converting step of turning on / off the gate of the first switching element by a gate control signal and converting the first DC power into second DC power determined according to the load;
  A first current detection step of detecting a current value in the second DC power converted by the DC-DC conversion step as a feedback DC current value;
  Multiplying the feedback DC current value by the feedback DC voltage value in the second DC power converted by the DC-DC conversion step, and from the basic power command value as the target value of the second DC power, The feedback power value of the multiplication result is subtracted, and based on the power deviation value of the subtraction result, a gate control signal for on / off control of the gate of the first switching element is output to control the second DC power Power control process to
  A DC-AC conversion step of turning on and off the gate of the second switching element by a switching signal to convert the second DC power into first high-frequency AC power;
  A high-frequency transformer converting step of electrically insulating the first high-frequency AC power by a high-frequency transformer and converting the first high-frequency AC power to a second high-frequency AC power supplied to the load;
  A second current detection step of detecting an output current value on the secondary side of the high-frequency transformer converted by the high-frequency transformer conversion step;
  When the switching signal for controlling on / off of the gate of the second switching element is output to control the first high-frequency AC power, the output current value and an arc reference value which is a detection reference of the arc discharge When the arc discharge is detected based on the above, a cut-off signal for cutting off the supply of high-frequency AC power to the load is generated, the output of the switching signal is stopped, the cut-off signal is generated, and then the predetermined signal is generated. An oscillation control step for outputting a switching signal in which the pulse width gradually increases from the initial pulse width to the set pulse width in order to restore the supply of the high-frequency AC power to the load after the time has elapsed;
With
  The oscillation control step stops the output of the P-side switching signal for turning on / off the gate of the second switching element for outputting the P-side (positive side) power when the arc discharge is detected. In this case, after the predetermined time has elapsed, an N-side switching signal for turning on / off the gate of the second switching element for outputting N-side (negative-side) power is designated as a P-side switching signal. When the output of the N-side switching signal for turning on / off the gate of the switching element for outputting the N-side power when the arc discharge is detected and the arc discharge is detected is stopped An arc suppression method that outputs a P-side switching signal before an N-side switching signal after a lapse of time.   The oscillation control step includes
  Converting the output current value into a voltage value, comparing the magnitude of the absolute value of the voltage value and the arc reference value, and outputting an arc signal when the absolute value is equal to or greater than the arc reference value; An arc detection step of outputting a reset signal after shutting off power supply to the load for a predetermined time after outputting a shutoff signal for shutting off power supply to the load;
  An initial pulse width command calculating step of calculating an initial pulse width based on the blocking signal and the reset signal;
  The initial pulse width, a switching frequency command value of a switching signal for controlling on / off of the gate of the second switching element, and a dead band period are input, and the pulse width is set within a predetermined time by the reset signal. A variable pulse width calculation / GATE control step for outputting a switching signal that gradually increases from the initial pulse width to the set pulse width;
The arc suppression method according to claim 10, comprising:   The arc detection step includes
  A current-voltage conversion step of converting the output current value into a voltage value;
  A differential amplification step of amplifying the voltage value and outputting the amplified output voltage value;
  An absolute value conversion step of calculating an absolute value of the output voltage value and outputting the absolute value;
  An arc reference setting step for setting the arc reference value;
  Comparing the absolute value with the arc reference value, and outputting the arc signal when the absolute value is equal to or greater than the arc reference value;
  A latch / shutoff signal generating step for holding the arc signal and outputting a shutoff signal;
  A restart signal calculation output step for outputting a reset signal after a predetermined time has elapsed since the gate of the second switching element is turned off by the shut-off signal, and releasing the held arc signal;
The arc suppression method according to claim 11, comprising:   The initial pulse width command calculation step includes:
  A pulse width attenuation ratio setting step for setting a pulse width attenuation ratio command value as a ratio of a predetermined pulse width to a set pulse width;
  An arc interruption command step for outputting an arc interruption signal based on the interruption signal;
  A rate command writing step for writing the pulse width attenuation ratio command value based on the arc interruption signal;
  A rate time setting step for setting a rate time required for the pulse width of the switching signal to change from the predetermined pulse width to the set pulse width;
  A rate calculation step of outputting the predetermined pulse width calculated from the rate time and a pulse width attenuation ratio command value by the reset signal;
  A minimum pulse width setting step for setting a minimum pulse width of the switching signal;
  Comparing the predetermined pulse width with the minimum pulse width, and selecting a larger pulse width as an initial pulse width;
The arc suppression method according to claim 11 or 12, characterized by comprising:   The power control step includes
  A new power command value is calculated by adding a swing power whose power waveform changes in a swinging manner to the basic power command value, and the feedback DC current value is multiplied by the feedback DC voltage value. The feedback DC power that is the multiplication result is subtracted from the power command value, and the second DC power is controlled by outputting the gate control signal of the first switching element based on the power deviation value that is the subtraction result. The arc suppression method according to any one of claims 10 to 13, wherein the arc suppression method is performed.

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