JP2013206784A - Microwave power supply device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To protect each microwave power supply part of a microwave power supply device that supplies a microwave power from a plurality of microwave power supply parts to a common load, against a reflection wave power with certainty.SOLUTION: A microwave power supply device is provided with: monitoring means 602 for specifying a microwave power supply part in which an abnormal state that a reflection wave power returned from a load 1 is larger than a setting value is generated, as a protection target power supply part; control target power supply part specification means 603 for temporarily stopping or reducing an output of each determination target power supply part while sequentially setting a plurality of microwave power supply parts P1 to P3 as the determination target power supply part to specify the microwave power supply part to be a control target for resolving the abnormal state of the protection target power supply part as a control target power supply part; and protection control means 604 for stopping or reducing an output of the specified control target power supply part to perform protection control for reducing the reflection wave power detected by the protection target power supply part to a setting value or less.

Description

  The present invention relates to a microwave power supply device that supplies microwave power to a plasma processing device such as a plasma generator, a material surface modification device, a plasma sputtering device, or a microwave processing device such as a dielectric heating device. .

  Etching is performed by applying plasma to the object to be processed such as semiconductor or liquid crystal, modifying the surface of the object by applying plasma to the surface of the object to be processed made of polymer material, and dielectric heating of the object to be processed For example, a microwave processing apparatus is used. In general, a microwave processing apparatus includes a chamber that accommodates an object to be processed. The microwave power supplied from the microwave power supply apparatus to the chamber causes plasma in the gas in the chamber to react with the object to be processed. Or the microwave power supplied into the chamber is absorbed by the object to be processed, and the object to be processed is heated.

  Although there is no clear definition of microwave, in this specification, microwave is a term that broadly encompasses electromagnetic waves having a short wavelength (generally, electromagnetic waves having a wavelength of 1 m or less) that are used for plasma treatment and dielectric heating treatment. The word is used.

  As shown in Patent Document 1, the microwave power supply apparatus includes a microwave power supply unit that outputs microwave power supplied to a load, a waveguide that connects the microwave power supply unit and the load, And a transmission line such as a coaxial cable, and the microwave power generated by the microwave power supply unit is supplied to the load (chamber) through the transmission line.

  In general, the microwave power supply unit of the microwave power supply device controls the output according to the function of detecting the traveling wave power supplied to the load and the reflected wave power returning from the load, and the control information given from the control unit And a function to start or stop the output in accordance with a command included in the control information, or to perform control to maintain the output value at the instruction value included in the control information.

  In some cases, only one microwave power supply unit that generates microwave power to be supplied to the load is provided for one load. However, the processing of the workpiece can be performed uniformly or efficiently. In order to do this, as shown in Patent Documents 1 and 2, a plurality of microwave power supply units may be provided for one load (chamber).

  The microwave generation source of the microwave power supply unit that outputs microwave power is configured by an electron tube such as a magnetron, or by a power amplifier that amplifies a microwave signal output from a microwave oscillator using a semiconductor element. Is done.

  In the microwave power supply device, if a mismatch occurs between the impedance viewed from the end of the transmission line and the impedance viewed from the end of the transmission line, the microwave power supply A part of the output traveling wave power is reflected by the load and returned to the microwave power supply unit as reflected wave power.

  In addition, when a configuration is adopted in which microwave power is supplied from a plurality of microwave power supply units to a common load, a part of the microwave power supplied from one of the microwave power supply units to the load is not absorbed by the load. When this occurs, the microwave power that has not been absorbed may enter a transmission line connected to another microwave power supply unit from the load side and reach the other microwave power supply unit as reflected wave power.

  In this specification, the term “reflected wave power” refers to the microwave power that is output from each microwave power supply unit and reflected back by the load, and the microwaves from a plurality of microwave power supply units to a common load. In the case where electric power is supplied, it is used to include both the microwave power that may enter each microwave power supply unit from the other microwave power supply unit side.

  When the amount of reflected wave power returning to the microwave power supply section increases, an excessive voltage may be applied to the microwave power supply section due to standing waves generated in the transmission path, and the microwave power supply section may be damaged. . Therefore, in the microwave power supply apparatus, as shown in Patent Document 2, an isolator is inserted between the microwave power supply unit and the load, and the reflected wave power is absorbed by the dummy load of the isolator. The microwave power supply unit is not allowed to reach.

  Further, when the reflected wave power exceeds a set value, control of suppressing the output of the microwave power supply unit is performed to suppress the reflected wave power to protect the microwave power supply unit.

JP 2004-128385 A JP 2000-223962 A

  In a microwave power supply device that provides a plurality of microwave power supply units for a common load and simultaneously supplies microwave power to the load from the plurality of microwave power supply units, the progress output from each microwave power supply unit The wave power may be reflected by the load and returned as reflected wave power. Of the microwave power output from other microwave power supplies, the power not absorbed by the load enters as reflected wave power. Therefore, the reflected wave power returning to the microwave power supply unit may be larger than when the microwave power is supplied to the load from only one microwave power supply unit.

  In this case, if an isolator with a small reflection tolerance is used, there arises a problem that it is necessary to limit the output of the microwave power supply unit in order to keep the reflected wave power returning from the load side below the reflection tolerance of the isolator. Therefore, in the microwave power supply apparatus that simultaneously supplies microwave power from a plurality of microwave power supply units to a common load, when using an isolator as means for protecting each microwave power supply unit from excessive reflected wave power, It is necessary to use a large isolator having a large withstand reflection, which increases the cost and increases the size of the apparatus.

  In order not to cause the above problems, it is preferable to use an isolator having a reflection resistance as small as possible even if it is not used at all or is used.

  In the case where a single microwave power supply unit is provided for the load, when it is detected that excessive reflected wave power has returned to the microwave power supply unit, the cause is detected from the microwave power supply unit. It can be specified that the output traveling wave power is reflected by the load. In this case, since it is possible to reliably attenuate the reflected wave power by performing control to suppress the output of the microwave power supply unit when it is detected that the reflected wave power exceeds the set value, the isolator The microwave power supply unit can be protected against the reflected wave power without using.

  On the other hand, in a microwave power supply apparatus in which a plurality of microwave power supply units are provided for a common load, the cause of excessive reflected wave power detected by any microwave power supply unit is not absorbed by the load. If the output of another microwave power supply unit has entered from the load side, even if control is performed to suppress the output of the microwave power supply unit in which excessive reflected wave power is detected, the microwave power supply unit Since the reflected wave power reaching the part cannot be attenuated, the microwave power source part may not be protected against the reflected wave power. In this case, in order to reliably protect each microwave power supply unit, an isolator having a large reflection resistance must be provided for each microwave power supply unit.

  An object of the present invention is to provide a configuration in which microwave power is supplied from a plurality of microwave power supply units to a common load, even if an isolator is not used at all or is used, a small and low reflection resistance is relatively small. An object of the present invention is to provide a microwave power supply apparatus that can reliably protect each microwave power supply unit against reflected wave power only by using a cost isolator.

  The present invention includes a plurality of microwave power supply units that output microwave power to be supplied to a common load, and a control unit that provides control information to the plurality of microwave power supply units. A microwave power supply device having a function of detecting traveling wave power supplied to a load and reflected wave power returning from the load and a function of controlling an output in accordance with control information given from a control unit set to target.

  In the present invention, the control unit acquires information on the reflected wave power detected in each microwave power supply unit, and whether or not the reflected wave power exceeding the set value is detected in each microwave power supply unit. Monitoring means for identifying a microwave power supply unit in which reflected wave power exceeding a set value is detected as a protection target power supply unit, and sequentially determining a plurality of microwave power supply units including the protection target power supply unit As described above, when the output of each determination target power supply unit is temporarily stopped or reduced, it is determined whether the reflected wave power detected by the protection target power supply unit is lower than the threshold value, and the output is stopped or reduced. Control target power supply specifying means for specifying the determination target power supply that has reduced the reflected wave power detected by the protection target power supply more than a threshold value as the control target power supply, and the output of the control target power supply Stop or reduce And a protection control means for providing the control target power unit control information required to perform protection control for reducing the reflected wave power detected by the protected power unit below the set value by.

In a microwave power supply device that supplies microwave power from a plurality of microwave power supply units to a common load, when the reflected wave power returning from the load side in each microwave power supply unit exceeds a set value, an abnormal state is assumed. There are two possible causes for the abnormal state.
(A) Since there is an impedance mismatch between the load side terminal section of the transmission line that transmits the output (traveling wave power) of the microwave power section to the load and the load, the microwave power section Output (traveling wave power) itself is reflected by the load.
(B) A part of the output of the other microwave power supply unit other than the microwave power supply unit in which the abnormal state occurs is not absorbed by the load and enters the microwave power supply unit in which the abnormal state occurs from the load side. Yes.

  When the cause of the abnormal state in which the reflected wave power returning from the load side in a certain microwave power supply unit exceeds the set value is the above (a), the output of the microwave power supply unit is stopped, Alternatively, if the amount of decrease is determined by an experimentally predetermined amount of decrease or a decrease amount determined according to the magnitude of the detected reflected wave power, the reflected wave power detected by the microwave power supply unit becomes zero. Or a drop above the threshold.

  When the cause of the abnormal state in which the reflected wave power returning from the load side in a certain microwave power supply unit exceeds the set value is the above (b), the other microwave power supply unit other than the microwave power supply unit When the output of any of the wave power supply units is stopped or decreased by an experimentally predetermined decrease amount or a decrease amount determined according to the magnitude of the reflected wave power detected, etc., the abnormal state is The reflected wave power detected by the generated microwave power supply unit becomes zero or falls below a threshold value.

  Accordingly, as in the present invention, each of the plurality of power supply units including the protection target power supply unit is set as a determination target power supply unit, and when the output of each determination target power supply unit is temporarily stopped or lowered (for each determination target power supply unit) Determine whether the reflected wave power detected by the power supply unit to be protected falls below the threshold and stop the output (when the output is stopped or lowered and then returned to the original level) Or, provided with a control target power supply unit specifying means for specifying the determination target power supply unit determined to have decreased the reflected wave power detected by the protection target power supply unit when the threshold value is reduced by a threshold value or more, as a control target power supply unit, It is possible to specify a control target power supply unit that needs to perform protection control to stop or reduce the output in order to eliminate an abnormal state in which reflected wave power exceeding the set value is detected by the protection target power supply unit. Power supply output By performing control to stop or decrease, it is possible to eliminate the abnormal condition.

  There may be only one power source unit to be protected, or there may be a plurality of power source units. Similarly, there may be only one power supply unit to be controlled, or there may be a plurality of power supply units.

  In another aspect of the present invention, the control unit acquires information on the reflected wave power detected in each microwave power supply unit, and the reflected wave power exceeding the set value is detected in each microwave power supply unit. Monitoring means that identifies whether or not the microwave power supply unit in which reflected wave power exceeding the set value is detected is the power supply unit to be protected, and the protection target by stopping or reducing the output of the power supply unit to be protected First protection control means for providing control information necessary for performing protection control to reduce the reflected wave power detected by the power supply section to a set value or less, and protection by the first protection control means When the reflected wave power detected by the protection target power supply unit cannot be reduced below the set value even if control is performed, each microwave power supply unit other than the protection target power supply unit is sequentially set as the determination target power supply unit. Target power supply It is determined whether or not the reflected wave power detected by the protection target power supply unit when the output is temporarily stopped or reduced, and when the output is stopped or reduced, the protection target power supply is detected. A control target power supply unit specifying means for specifying a determination target power supply unit that has reduced the level of reflected wave power detected by the control unit by a threshold value or more, and stopping or reducing the output of the control target power supply unit And a second protection control means for providing control information necessary for performing protection control to reduce the reflected wave power detected by the protection target power supply unit to a set value or less.

  In another aspect of the present invention, the control unit acquires information on the reflected wave power detected in each microwave power supply unit, and the reflected wave power exceeding the set value is detected in each microwave power supply unit. Monitoring means that identifies whether or not the microwave power supply unit where the reflected wave power exceeding the set value is detected is identified as the protection target power supply unit, and other microwave power supply units other than the protection target power supply unit are sequentially determined. As the target power supply unit, determine whether or not the level of the reflected wave power detected by the protection target power supply unit when the output of each determination target power supply unit is temporarily stopped or reduced, or lower than a threshold value, A control target power supply unit specifying means for specifying, as a control target power supply unit, a determination target power supply unit that reduces the level of reflected wave power detected by the protection target power supply unit when the output is stopped or reduced; Specific power supply to be controlled Control information necessary for performing protection control for reducing the reflected wave power detected by the protection target power supply unit to be equal to or lower than the set value by stopping or reducing the output of the control target power supply unit specified by Detected by the protection target power supply unit by stopping or reducing the output of the protection target power supply unit when the control target power supply unit is not specified by the first protection control unit given to the power supply unit and the control target power supply unit specifying unit And second protection control means for performing protection control for reducing the reflected wave power to be equal to or lower than a set value.

  In another aspect of the present invention, the control unit includes output return control means for performing output return control for returning the output of the control target power supply unit to a specified level every time a predetermined time elapses while protection control is being performed. In addition.

  With this configuration, unnecessary protection control is performed after the cause of the abnormal state in the protection target power supply unit is eliminated, and the microwave power supplied to the load is limited. Can be prevented.

  In another aspect of the present invention, the control unit includes output control means for providing control information to each microwave power supply unit so that the output of each microwave power supply unit matches a target value. This output control means increases the output of the microwave power supply unit other than the control target power supply unit when the protection control is being performed, thereby setting the total amount of power given to the load from the plurality of microwave power supply units to the target value. It is configured to perform control to keep.

  If comprised as mentioned above, it can prevent that the microwave electric power supplied to load when protection control is performed is insufficient, and can prevent that a to-be-processed object produces a defect.

  In still another aspect of the present invention, the control unit includes output control means for giving control information to each microwave power supply unit so that the output of each microwave power supply unit matches a target value. The total amount of power absorbed by the load is calculated from the traveling wave power and the reflected wave power detected by each power detector of the plurality of microwave power supply units, and the calculated total amount of power is maintained at the target value. Control information is given to each microwave power source so as to perform control.

  With the above configuration, the microwave power absorbed by the load can be kept constant regardless of whether protection control is being performed, so that the microwave power supply unit can be properly protected. However, it is possible to prevent the processing object from being defective by always properly processing the processing object.

  The control unit needs to exchange signals for transmitting reflected wave information and control information with each of the plurality of microwave power supply units in order to configure each of the above-described means. In this case, the configuration for exchanging signals between the control unit and each microwave power supply unit can take various forms. In one aspect of the present invention, the control unit and each microwave power supply unit are connected through a communication line. In this case, the control unit is configured to send and receive signals necessary for operating each means through a communication line provided between each microwave power source unit.

  In another aspect of the present invention, a control device that transmits and receives signals to and from each microwave power supply unit is provided in common to a plurality of microwave power supply units, and the control device is provided in each microwave power supply unit. Connected through communication line. In this case, the control unit is configured to transmit and receive signals necessary for operating each means via the control device.

  In another aspect of the present invention, a control device is provided that exchanges signals with other microwave power supply units in one microwave power supply unit selected from among a plurality of microwave power supply units, The one microwave power supply unit and the other microwave power supply unit are connected through a communication line. In this case, the control unit is connected to one selected microwave power supply unit through a communication line, and exchanges signals necessary for operating each means via the control device in one microwave power supply unit. Configured.

  According to the present invention, when microwave power is supplied from a plurality of microwave power supply units to a common load, the microwave power supply unit in which the reflected wave power returning from the load exceeds a set value is protected. Detected by the protection target power supply unit when the output of each determination target power supply unit is temporarily stopped or reduced, with the target power supply unit and the plurality of microwave power supply units including the protection target power supply unit as the determination target power supply units. Judgment target power supply unit that determines whether or not the reflected wave power is lower than the threshold value and reduces the reflected wave power detected by the protection target power supply unit when the output is stopped or reduced As a control target power supply unit, the reflected wave power detected by the protection target power supply unit is kept below the set value by stopping or reducing the output of the specified control target power supply unit. , Double It can be achieved from the microwave power supply unit to ensure the protection of the microwave power supply unit of the microwave power supply apparatus for supplying microwave power to a common load.

  In the present invention, it does not prevent the isolator from being inserted between the microwave generation source and the load. However, according to the present invention, the level of the reflected wave power detected by the protection target power supply unit is set to the set value. Since the control to keep the following is performed, even if an isolator is provided, a small and inexpensive one having a smaller reflection resistance than that conventionally used can be used.

1 is a block diagram schematically showing a configuration of an embodiment of the present invention. FIG. 2 is a block diagram illustrating an example of a configuration that a control unit can take in the embodiment illustrated in FIG. 1. In the embodiment shown in FIG. 1, it is the block diagram which showed the other example of the structure which a control part can take. In the embodiment shown in FIG. 1, it is the block diagram which showed the further another example of the structure which a control part can take. It is the block diagram which showed schematically the structure of other embodiment of this invention. It is the block diagram which showed schematically the structure of other embodiment of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 schematically shows a configuration of a first embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a load to which microwave power is supplied, which accommodates an object to be processed by the microwave. It is a chamber. P1 to P3 are first to third microwave power supply units that output the microwave power supplied to the load 1, respectively. In the microwave power supply apparatus targeted by the present invention, a plurality of microwave power supply units are provided for the common load 1, but in this embodiment, three microwave power supply units are provided.

  Each microwave power supply unit detects a microwave generation source 2 that generates microwave power, a traveling wave power output from the microwave generation source 2, and a reflected wave power that returns from the load to the microwave generation source. And a detector 3. In the present embodiment, the microwave generation source 2 includes a microwave oscillation source using an electron tube such as a magnetron, and an output control unit that controls the output of the microwave oscillation source. The power detector 3 includes an input port 3a and an output port 3b, two coupling ports 3c and 3d that output a traveling wave detection signal Sf proportional to traveling wave power and a reflected wave detection signal Sr proportional to reflected wave power, respectively. It consists of a bidirectional directional coupler having The output end of the microwave generation source 2 is connected to the input port 3a of the power detector 3 through the transmission line 4 made of a waveguide, and the output port 3b of the power detector 3 is connected to the load 1 through the transmission line 5 made of the waveguide. It is connected to the.

  Reference numeral 6 denotes a control unit provided for the first to third microwave power sources P1 to P3. Between the control unit 6 and the first to third microwave power sources P1 to P3, communication lines C11 to C13 and They are connected through C21 to C23. In the present embodiment, the traveling wave information and the reflected wave obtained from the traveling wave detection signal Sf and the reflected wave detection signal Sr output from the power detector 3 provided in the first to third microwave power sources P1 to P3, respectively. Information is given to the control unit 6 through communication means provided in the respective microwave generation sources 2 of the first to third microwave power sources P1 to P3 and the communication lines C11 to C13. In addition, the control unit 6 instructs the microwave generation sources 2 of the first to third microwave power sources P1 to P3 to generate / stop the respective outputs, and commands to instruct the magnitudes of the respective outputs. The control information Sc including the above is given through the communication lines C21 to C23.

  The control unit 6 includes a CPU, a storage device such as a ROM and a RAM, and a microprocessor having an input / output interface. The control unit 6 causes the CPU to execute a predetermined program stored in the ROM, so that various function realization means are provided. Configure. FIG. 2 shows an example of the configuration of the apparatus including the function realization means provided in the control unit 6 in this embodiment. In this example, the devices are provided in the first to third microwave power supply units P1 to P3, respectively. An output control means 601 for controlling the output of the generated microwave generation source 2 and a power supply unit in which an abnormal state in which reflected wave power exceeding a set value is detected is generated in the plurality of microwave power supply units P1 to P3. A monitoring unit 602 for monitoring whether or not there is, a control target power source specifying unit 603 for specifying a microwave power source to be controlled in order to eliminate an abnormal state, and a control target power source for eliminating the abnormal state The control unit 6 is provided with protection control means 604 for controlling the unit.

  The output control means 601 shown in FIG. 2 performs generation and stop of the output of the microwave generation source 2 of the microwave power supply units P1 to P3, and control for maintaining the output of the microwave power supply unit at a target value. It is means for giving control information to each microwave power source. The output control means 601 is provided with control information including information on the target value of the output (traveling wave power) of the microwave power supply units P1 to P3 in each microwave generation source 2 of the microwave power supply units P1 to P3. To the output control unit. The output control unit provided in each microwave generation source 2 calculates the target value of the output included in the control information supplied from the control unit 6 and the traveling wave power detected by the power detector 3 in each microwave power supply unit. By controlling the voltage applied to the electron tubes constituting the microwave generation source 2 so that the deviation from the level becomes zero, control is performed to maintain the microwave power output from the microwave generation source 2 at a target value. .

  The monitoring means 602 determines whether an abnormal state has occurred in each microwave power supply unit, with the power detector 3 provided in each microwave power supply unit detecting a reflected wave power exceeding the set value Prs as an abnormal state. Is monitored, and all the microwave power supply units in which an abnormal state occurs are specified as protection target power supply units. If excessive reflected wave power returns from the load to each micro power supply unit, the electron tube (magnetron or the like) constituting the microwave generation source 2 may be overheated or abnormally oscillated and damaged. When using an isolator to protect the microwave power supply from reflected waves, set the reflected wave power to the limit value of the reflection withstand capability of the isolator (to keep the heat generated in the isolator dummy load within an allowable range. Set the limit value). When the isolator is not used, the reflected wave power set value Prs is set to the maximum value of the reflected wave power level that is allowed to operate without damaging the microwave power supply (for example, the magnetron is overheated). And the maximum value allowed for operation without causing abnormal oscillation).

  Whether the control target power supply unit specifying unit 603 shown in FIG. 2 temporarily stops the output Pf of each determination target power supply unit using a plurality of microwave power supply units including the protection target power supply unit as sequential determination target power supply units. Or, it is configured to determine whether or not the reflected wave power detected by the protection target power supply unit when it is temporarily reduced by a predetermined reduction amount ΔPfy shows a reduction of the threshold value ΔPrth or more. When the reflected wave power Pr detected by the protection target power supply unit when the output of the target power supply unit is stopped or decreased by ΔPfy falls below the threshold value ΔPrth, the determination target power supply unit is selected as the control target power supply unit As specified. The illustrated control target power supply unit specifying unit 603 instructs the microwave power supply units P1 to P3 to be sequentially determined target power supply units, and temporarily stops the output of each determination target power supply unit or decreases it by ΔPfy. When the control information is given to the output control unit 601 and the output of each determination target power supply unit is stopped or lowered, the reflected wave power detected by the power detector 3 of the protection target power supply unit specified by the monitoring unit 602 is It is determined whether or not the amount of decrease ΔPry is equal to or greater than the threshold value ΔPrth. In this determination process, when the output of a certain determination target power supply unit is stopped or decreased by ΔPfy, the reflected wave power detected by the protection target power supply unit decreases by a decrease amount ΔPry equal to or greater than the threshold value ΔPrth Then, the determination target power supply unit is specified as the control target power supply unit.

  When specifying the control target power supply unit, if the method of temporarily stopping the output of the determination target power supply unit is taken, it is possible to increase the amount of decrease in the reflected wave power detected by the protection target power supply unit, The control target power supply unit can be identified most reliably. However, when there is a concern that the load may be adversely affected if the output of the determination target power supply unit is temporarily stopped, the output of the determination target power supply unit is temporarily decreased by a predetermined reduction amount ΔPfy. It is preferable to specify the control target power supply unit by a method of determining whether or not the reflected wave power detected by the protection target power supply unit shows a decrease amount ΔPry that is equal to or greater than the threshold ΔPrth.

  A configuration for specifying a control target power supply unit by determining whether or not the reflected wave power detected by the protection target power supply unit has decreased by a threshold value or more when the output of each determination target power supply unit is temporarily reduced When the determination is made, the decrease amount ΔPfy of the output of each determination target power supply unit when performing the determination may be a predetermined amount experimentally determined in advance, or the level of the reflected wave power detected by the protection target power supply unit, It may be a variable amount determined by applying the target value of the output of the microwave power supply unit to an empirical formula prepared in advance. However, in order to prevent the decrease in the output of the microwave power supply unit in the process of identifying the control target power supply unit as much as possible, the amount of decrease in the output of each determination target power supply unit at the time of determination is set. It is desirable to set a value as small as possible within a range that does not hinder the specification of the power supply unit to be controlled. The threshold value ΔPrth is appropriately set according to the output reduction amount ΔPfy of each determination target power supply unit at the time of determination.

  The protection control unit 604 stops the output of the control target power supply unit specified by the control target power supply unit specifying unit 603, or suppresses the detected value of the reflected wave power detected by the protection target power supply unit to a set value or less. Is a means for performing protection control to reduce the reflected wave power detected by the power supply unit to be protected to a set value or less by reducing it by the required reduction amount ΔPfx. The protection control unit 604 gives a command to the output control unit 601 to stop the output of the control target power supply unit specified by the control target power supply unit specifying unit 603 or to reduce the output by a predetermined decrease amount ΔPfx.

  In order to minimize the influence on the load, if the method of stopping the output of the power supply unit to be controlled is taken in the protection control, the power supplied to the load may be reduced and the load may be adversely affected. It is possible. Therefore, unless it is unavoidable to protect the power supply unit to be protected, the protection control detects the output of the power supply unit to be protected by reducing the output of the control target power supply unit by the necessary minimum amount ΔPfx. It is preferable to reduce the reflected wave power to be lower than a set value.

  In the protection control, the output reduction amount ΔPfx when performing the control for reducing the output of the control target power supply unit is a value sufficient to suppress the reflected wave power detected by the protection target power supply unit to a set value or less. And a value that can keep the decrease in the microwave power supplied to the load within an allowable range. The optimum reduction amount of the output of the control target power supply unit when performing protection control is, for example, the level Pr of the reflected wave power exceeding the set value Prs detected by the protection target power supply unit when the protection target power supply unit is specified. And the set value Prs, ΔPr = Pr−Prs, the decrease amount ΔPfy of the output of the determination target power supply unit when specifying the control target power supply unit, and the reflected wave power detected by the protection target power supply unit at that time It can be calculated by searching an experimentally created map for the amount of decrease ΔPry that is equal to or greater than the threshold value ΔPrth, or by applying ΔPr, ΔPfy, and ΔPry to an empirical formula that has been created in advance.

As described above, there are two possible causes for the reflected wave power detected by the protection target power supply unit exceeding the set value.
(A) Since there is an impedance mismatch between the load side terminal section of the transmission line 5 for transmitting the output (traveling wave power) of the protection target power supply section to the load, the protection target power supply Output (traveling wave power) itself is reflected by the load.
(B) A part of the output of the microwave power supply unit other than the protection target power supply unit is not absorbed by the load and enters the protection target power supply unit from the load side.

  When the cause of the abnormal state in which the reflected wave power returning from the load side in the protection target power supply unit exceeds the set value is (a) above, the output of the protection target power supply unit is stopped or reduced. As a result, the reflected wave power detected by the protection target power supply unit becomes zero or falls below a set value.

  When the cause of the abnormal state in which the reflected wave power returning from the load 1 side in the protection target power supply unit exceeds the set value is the above (b), the microwaves other than the protection target power supply unit When any output of the power supply unit is stopped or reduced, the reflected wave power detected by the protection target power supply unit becomes zero or falls below a set value.

  Therefore, when all the microwave power supply units including the protection target power supply unit in which an abnormal state has occurred are sequentially set as the determination target power supply units, the output of each determination target power supply unit is temporarily stopped or reduced (each determination target When it is determined whether or not the reflected wave power detected by the power supply unit to be protected falls below the set value (when the operation of returning to the original level after stopping or reducing the output of the power supply unit is performed) Can be specified as the control target power supply unit, and the control target power supply unit that has reduced the reflected wave power detected by the protection target power supply unit to be equal to or lower than the set value can be specified. By performing protection control for stopping or reducing the output of the target power supply unit, it is possible to eliminate an abnormal state occurring in the protection target power supply unit.

  For example, in this embodiment, it is assumed that the reflected wave power exceeding the set value is detected by the power detector 3 of the first microwave power supply unit P1. If this state is left as it is, the microwave generation source 2 of the first microwave power supply unit P1 may be damaged. When an isolator is provided, the reflected wave power may exceed the reflection tolerance of the isolator and the isolator may be damaged. At this time, the monitoring unit 602 identifies the first microwave power supply unit P1 as the protection target power supply unit. Here, the cause of the abnormal state (a state in which the reflected wave power exceeding the set value is detected) occurs in the first microwave power supply unit P1 is that the output of the first microwave power supply unit P1 is reflected by the load. If the output of the microwave generation source 2 of the first microwave power supply unit P1 is stopped or reduced, the power detector 3 of the first microwave power supply unit P1 is assumed. Although the reflected wave power detected at 1 becomes zero or shows a decrease over the threshold value, the first microwave power supply unit P1 does not stop or decrease the output of the other microwave power supply units P2 and P3. The reflected wave power detected does not show a decrease over the threshold value. In this case, the protection target power supply unit (first microwave power supply unit P1) itself is used as the control target power supply unit, and the output of the first microwave power supply unit P1 is stopped or lowered, thereby By limiting the reflected wave power detected by the power detector 3 of the part P1 to a set value or less, it is possible to prevent the microwave generation source part of the protection target power supply part from being damaged.

  Further, even when the output of the first microwave power supply unit P1 is reduced when the first microwave power supply unit P1 is a protection target power supply unit, the power detector 3 of the first microwave power supply unit P1 If the detected reflected wave power does not show a decrease beyond the threshold value, a part of the outputs of the other microwave power supply units P2 and / or P3 is not absorbed by the load 1 and passes through the transmission line 5. Since it has entered the microwave power supply unit P1, it can be determined that the reflected wave power detected by the first microwave power supply unit P1 exceeds the set value. In this case, other microwave power supply units P2 and / or P3 that have caused an abnormal state in the first microwave power supply unit P1 that is the protection target power supply unit are used as control target power supply units, and other microwaves are used. The protection target power supply part P1 can be protected by performing protection control for stopping or reducing the output of the power supply parts P2 and / or P3.

  The number of microwave power supply units in which an abnormal state in which reflected wave power of a set value or more returns from the load is not limited to one, and abnormal states may occur in a plurality of microwave power supply units at the same time. Accordingly, there may be a single power supply unit to be protected or a plurality of power supply units.

  In addition, the number of microwave power supply units that cause the abnormal state in the protection target power supply unit is not limited to one, and a plurality of microwave power supply units cause the abnormal state in the protection target power supply unit at the same time. There can be. Accordingly, there may be one control target power supply unit or a plurality of power supply units. The control target power supply unit may be the protection target power supply unit itself, or may be a microwave power supply unit other than the protection target power supply unit.

  In the above embodiment, for example, it is assumed that the power detector 3 of the first microwave power supply unit P1 detects reflected wave power exceeding a set value. At this time, the monitoring unit 602 identifies the first microwave power supply unit P1 as the protection target power supply unit. When the protection target power supply unit is specified, the control target power supply unit specifying unit 603 temporarily stops or reduces the output of each determination target power supply unit using the microwave power supply units P1 to P3 as sequential determination target power supply units. When the output of each determination target power supply unit is stopped or reduced, it is determined whether or not the reflected wave power detected by the protection target power supply unit falls below a set value. In the process of this determination, when it is determined that the output stop or reduction of a certain determination target power supply unit has reduced the reflected wave power detected by the protection target power supply unit by a threshold value or more, the determination target power supply unit is In order to eliminate the abnormal state of the protection target power supply unit, it is specified as a control target power supply unit that needs to perform protection control to stop or reduce the output.

  For example, when the control target power supply unit specifying unit 603 performs an operation of temporarily stopping or reducing the output of the second microwave power supply unit P2 and then returning it to the original level, the power detector of the protection target power supply unit P1 If the level of the reflected wave power detected in step 3 decreases below the set value, the control target power supply unit specifying unit 603 specifies the second microwave power supply unit P2 as the control target power supply unit. At this time, the protection control means 604 uses the second microwave power supply unit P2 as a control target power supply unit, and stops the output or controls information (microwave power supply unit) required to reduce the output by a predetermined reduction amount ΔPfx. The target value of the output of P2) is given to the microwave power supply unit P2. Thereby, the reflected wave power detected by the power detector 3 of the first microwave power supply unit P1 which is the power supply unit to be protected is attenuated to a set value or less, thereby protecting the first microwave power supply unit P1. .

  In the above description of the operation, only one microwave power supply unit is set as the protection target power supply unit. However, when a plurality of protection target power supply units are specified, the control target power supply unit specifying unit 603 determines each protection target power supply unit. The control target power supply unit that needs to be controlled in order to reduce the detected reflected wave power level below the set value is specified, and the output of the specified control target power supply unit is stopped by the protection control means 604 Or the control which lowers is performed and the abnormal condition which has arisen in each protection target power supply part is eliminated.

  In the above embodiment, after the protection target power supply unit is specified by the monitoring unit 602, all the microwave power supply units are sequentially set as the determination target power supply units, and the output of each determination target power supply unit is temporarily stopped or reduced. Thus, all the control target power supply units are specified, but when the protection target power supply unit is specified, first, the control target power supply unit performs control to stop or reduce the output of the protection target power supply unit itself. It is determined whether or not the detected reflected wave power falls below a set value, and even if the output of the protection target power supply unit itself is stopped or lowered, the reflected wave power detected by the protection target power supply part is below the set value. When the voltage does not decrease to a certain level, the output of the microwave power supply unit other than the protection target power supply unit may be temporarily stopped or reduced to specify the control target power supply unit. A configuration example of the control unit in the case of such a configuration is shown in FIG.

  In FIG. 3, reference numeral 601 denotes output control means, and reference numeral 602 denotes monitoring means, which are configured in the same manner as in the embodiment shown in FIG. In other words, the output control means 601 generates and stops the output of the microwave generation source 2 of the microwave power supply units P1 to P3 and controls the microwave power supply units to maintain the output of the microwave power supply unit at a target value. Control information including a target value information of the outputs (traveling wave power) of the microwave power supply units P1 to P3 is supplied to each microwave generation source 2 of the microwave power supply units P1 to P3. Is provided to the output control unit provided in. Further, the monitoring means 602 monitors whether or not an abnormal state has occurred in each microwave power supply unit, with the state in which the power detector of each microwave power supply unit detects reflected wave power exceeding the set value as an abnormal state. And identify all microwave power supplies that are in an abnormal state as protected power supplies

  The first protection control unit 604a detects the protection target power supply unit by stopping the output of the protection target power supply unit specified by the monitoring unit 602 as the control target power supply unit or reducing the output by a predetermined decrease amount ΔPfx. Control information necessary for performing protection control to keep the reflected wave power below the set value is given to the microwave power supply units P1 to P3.

  The control target power supply unit specifying unit 603 only when the first protection control unit performs control to stop or reduce the output of the protection target power supply unit, only when the abnormal state occurring in the protection target power supply unit is not resolved. It is a means for specifying the control target power supply unit from among the microwave power supply units other than the protection target power supply unit. The control target power supply unit 603 according to the present embodiment, when the protection control by the first protection control unit 604a is performed, does not eliminate the abnormal state occurring in the protection target power supply unit, other micros other than the protection target power supply unit. Determine whether or not the level of the reflected wave power detected by the protection target power supply unit decreases when the output of each determination target power supply unit is temporarily stopped or reduced, with the wave power supply unit as the sequential determination target power supply unit Then, the determination target power supply unit that reduces the level of the reflected wave power detected by the protection target power supply unit when the output is stopped or reduced is specified as the control target power supply unit.

  The second protection control unit 604b stops the output of the control target power supply unit specified by the control target power supply unit specification unit 603 or lowers it below a specified level, thereby detecting the reflected wave detected by the protection target power supply unit. Control information necessary for performing protection control to keep the power below the set value is given to the microwave power supply units P1 to P3.

  In this configuration, there is a high probability that reflection will occur at the load of each microwave power supply unit, and there is a probability that part of the output of each microwave power supply unit will not be absorbed by the load and enter another microwave power supply unit from the load side. It is advantageous when it is low.

  In the embodiment shown in FIG. 3, for example, it is assumed that the power detector 3 of the first microwave power supply unit P1 detects reflected wave power exceeding a set value. At this time, the monitoring unit 602 identifies the first microwave power supply unit P1 as the protection target power supply unit. When the protection target power supply unit is specified, first, the first protection control unit 604a gives a command to the output control unit 601 to stop or reduce the output of the first microwave power supply unit P1. As a result, when the level of the reflected wave power detected by the power detector 3 of the first microwave power supply unit P1 shows a decrease beyond the threshold, the output of the first microwave power supply unit P1 is stopped. Alternatively, the first microwave power supply unit P1 is protected as it is lowered. The level of the reflected wave power detected by the power detector 3 of the first microwave power supply P1 even if the first protection control means 604a performs control to stop or reduce the output of the first microwave power supply P1. When the value does not fall below the set value, the second microwave power supply units P2 and P3 are sequentially set as the determination target power supply units, and the operation of returning to the original level after temporarily stopping or reducing the output of each determination target power supply unit is performed. It is determined whether or not the reflected wave power detected by the protection target power supply unit when the output of each determination target power supply unit is stopped or reduced is reduced to a set value or less. This determination process eliminates the abnormal state of the protection target power supply unit for the determination target power supply unit that reduces the reflected wave power detected by the protection target power supply unit when the output is stopped or reduced. Therefore, the control target power supply unit that needs to perform protection control to stop or reduce the output is specified.

  For example, when the control target power supply unit specifying unit 603 performs an operation of temporarily stopping or reducing the output of the second microwave power supply unit P2 and then returning it to the original level, the power detector 3 of the protection target power supply unit P1. If the level of the reflected wave power detected in step S1 falls below the set value, the control target power supply unit specifying unit 603 specifies the second microwave power supply unit P2 as the control target power supply unit. At this time, the second protection control unit 604b uses the second microwave power supply unit P2 as a control target power supply unit, and controls to stop or reduce the output of the control target power supply unit by giving a command to the output control unit 601. Control information necessary for performing is provided to the microwave power supply unit P2. Thereby, the reflected wave power detected by the power detector 3 of the first microwave power supply unit P1 which is the power supply unit to be protected is attenuated to a set value or less, thereby protecting the first microwave power supply unit P1. .

  In the above configuration, when the monitoring target power source unit is specified by the monitoring unit 602, the first protection control unit first performs control to stop or reduce the output of the protection target power source unit. Protection control that first identifies a control target power supply unit from among other microwave power supply units other than the protection target power supply unit and stops or reduces the output of the control target power supply unit when the protection target power supply unit is specified by When the abnormal state that has occurred in the protection target power supply unit cannot be resolved even by this protection control, the protection target power supply unit may be set as the control target power supply unit, and control for stopping or reducing the output may be performed.

  A configuration example of the control unit 6 in the case where such control is performed is shown in FIG. In the embodiment shown in FIG. 4, the configurations of the output control unit 601 and the monitoring unit 602 are the same as those in the embodiment shown in FIGS.

  In the embodiment shown in FIG. 4, the control target power supply unit specifying unit 603 uses each microwave power supply unit other than the protection target power supply unit specified by the monitoring unit 602 as a determination target power supply unit in order. Determine whether the level of the reflected wave power detected by the protection target power supply unit when the output of the unit is temporarily stopped or temporarily lower than the specified level, and the output is stopped or The determination target power supply unit that has reduced the level of the reflected wave power detected by the protection target power supply unit when it is reduced is identified as the control target power supply unit that needs to control the output in order to eliminate the abnormal state Composed.

  The first protection control unit 604a stops the output of the specified control target power supply unit when the control target power supply unit is specified by the control target power supply unit specifying unit 603, or lowers the output from the specified level. The microwave power supply units P1 to P3 are configured to provide control information necessary for performing protection control for keeping the reflected wave power detected by the power detector 3 of the protection target power supply unit below a set value.

  The second protection control unit 604b is configured to stop the output of the protection target power supply unit when the control target power supply unit specifying unit 603 does not specify the control target power supply unit, or lower the output level from a specified level. Control information necessary to perform protection control for keeping the reflected wave power detected by the power supply unit below a set value is provided to the microwave power supply units P1 to P3.

  In the embodiment shown in FIG. 4, for example, when the power detector 3 of the first microwave power supply unit P1 detects reflected wave power exceeding the set value, the monitoring unit 602 protects the first microwave power supply unit P1. Specify the target power supply. When the protection target power supply unit is specified, the control target power supply specifying unit 603 uses the microwave power supply units P2 and P3 other than the protection target power supply unit as sequential determination target power supply units, and outputs the output of each determination target power supply unit once. Whether the reflected wave power detected by the protection target power supply unit falls below the set value when the output of each judgment target power supply unit is stopped or reduced by performing an operation to return to the original level after the stop or reduction Determine whether. When the output is stopped or reduced in the process of this determination, the determination target power supply unit in which the reflected wave power detected by the protection target power supply unit is reduced below the set value is eliminated from the abnormal state of the protection target power supply unit P1. Therefore, the control target power supply unit that needs to perform protection control to stop or reduce the output is specified.

  For example, when the operation of returning to the original level after temporarily stopping or reducing the output of the second microwave power supply part P2 is performed, the reflected wave power detected by the power detector 3 of the protection target power supply part P1 When the level falls below the set value, the second microwave power supply unit P2 is specified as the control target power supply unit. At this time, the first protection control unit 604a uses the second microwave power supply unit P2 as a control target power supply unit to stop or reduce the output of the control target power supply unit P2 by giving a command to the output control unit 601. To do. Thereby, the reflected wave power detected by the power detector 3 of the power supply unit P1 to be protected is attenuated to a set value or less to protect the first microwave power supply unit P1.

  When the control target power supply specifying unit 603 cannot specify the control target power supply, that is, the control target power supply specifying unit 603 uses the second microwave power supply units P2 and P3 as sequential determination target power supply units. When the reflected wave power detected by the protection target power supply unit P1 does not decrease below the set value when the operation of returning to the original level after temporarily stopping or decreasing the output of each determination target power supply unit is performed, The second protection control means 604b gives a command to the output control means 601 to stop or reduce the output of the first microwave power supply unit P1. As a result, the level of the reflected wave power detected by the power detector 3 of the first microwave power supply unit P1 is lowered to a set value or less, thereby protecting the first microwave power supply unit P1.

  As described above, in the present invention, when an abnormal state occurs in which the reflected wave power returning from the load exceeds a set value in any microwave power supply unit, the microwave power supply unit is used as a protection target power supply unit. The reflected wave detected by the protection target power supply unit by stopping or lowering the output of the control target microwave power supply unit identified from the protection target power supply unit or other microwave power supply unit other than the protection target power supply unit Basically, protection control is performed to reduce the power below the set value. However, if protection control is continued, the state in which the microwave power supplied to the load is insufficient continues to hinder processing of the workpiece. There is a risk. In order to prevent such a situation from occurring, there is provided an output return control means for performing output return control for returning the output of the control target power supply unit to a specified level every time a certain time elapses while protection control is being performed. It is preferable to keep it.

  When the output return control unit as described above is provided, when the output return control unit returns the output of the control target power supply unit to the specified level and the microwave power supply unit that has been protected still has an abnormal state The protection control is performed again to protect the protection target power supply unit. If the output recovery control means returns the output of the control target power supply unit to the specified level, and no abnormal state has occurred in the protection target power supply unit (when the cause that caused the abnormal state has been removed) Since protection control is not performed thereafter, the microwave power supply apparatus can be returned to a normal state.

  If the rated output of each microwave power supply unit can be given a margin, a plurality of microwave power supply units can be increased by increasing the output of the microwave power supply unit other than the control target power supply unit when protection control is performed. It is preferable to configure the output control means 601 so as to perform control to keep the total amount of power applied from the power supply unit to the load at a target value.

  By configuring the output control means 601 in this way, the total amount of microwave power supplied to the load can be maintained at a level required by the load even when protection control is being performed. Processing of processed objects can be performed without hindrance.

  If the rated output of each microwave power supply unit can be given a margin, the traveling wave power and the reflected wave power detected by the respective power detectors 3 of the plurality of microwave power supply units P1 to P3 are used. It is preferable to configure the output control means so as to perform control for calculating the total amount of power absorbed by the load 1 and maintaining the calculated total amount of power at a target value.

  The amount of microwave power output from each microwave power supply unit and absorbed by the load 1 is obtained by subtracting the reflected wave power from the traveling wave power detected by the power detector 3 of each microwave power supply unit. The total amount of power absorbed by the load can be obtained by adding the amount of power output from each of the microwave power supply units and absorbed by the load.

  Thus, if the output control means 601 is configured to perform control to keep the total amount of power absorbed by the load at the target value, the processing of the object to be processed can be performed more accurately.

  In each of the above embodiments, the control unit 6 is provided in common for the plurality of microwave power supply units P1 to P3, and the control unit 6 and each microwave power supply unit are connected through a communication line to control Necessary for operating each means such as the output control means 601, the monitoring means 602, the control target power supply part specifying means 603, the protection control means 604, etc. through a communication line provided between each part and each microwave power supply part. It is configured to send and receive signals. However, the present invention is not limited to such a configuration, and the configuration for exchanging signals between the control unit and each microwave power supply unit can take various forms. .

  For example, as shown in FIG. 5, a control device 7 that exchanges signals with the microwave power supply units P1 to P3 is provided in common to the plurality of microwave power supply units P1 to P3. Each microwave power supply unit is connected through a communication line, and the control unit 6 and the control device 7 are connected through communication lines C1 and C2, and output control means 601, monitoring means 602, control target power supply part specifying means 603, The control unit 6 may be configured to transmit and receive signals necessary for operating each unit such as the protection control unit 604 via the control device 7.

  In addition, as shown in FIG. 6, another microwave power source is included in one microwave power source unit (second microwave power source unit P2 in the illustrated example) selected from the plurality of microwave power source units P1 to P3. A control device for transmitting and receiving signals to and from the unit is provided, and the microwave power supply unit P2 provided with this control device and the other microwave power supply units P1 and P3 are connected through communication lines C3 and C4. The control unit 6 is connected through the communication lines C1 and C2 between the microwave power source P2 provided with the control device and the control unit 6, and the control unit 6 outputs the output control unit 601, the monitoring unit 602, and the control target power source unit specifying unit 603 Further, it is also possible to configure such that signals necessary for operating each means such as the protection control means 604 are transmitted via a control device in one microwave power supply unit P2.

  In the above embodiment, the microwave generation source 2 is configured by an electron tube such as a magnetron. However, the microwave generation source is a power amplifier that amplifies a microwave signal output from a microwave oscillator using a semiconductor element. Can also be configured.

  In the present invention, etching is performed by applying plasma to an object to be processed such as a semiconductor or a liquid crystal, modifying the surface of the object by applying plasma to the surface of the object to be processed made of a polymer material, It can be widely used in the industrial field of a microwave power supply device that supplies microwave power to a load to perform dielectric heating of an object.

DESCRIPTION OF SYMBOLS 1 Load 2 Microwave generation source 3 Electric power detector 4 Transmission path 5 Transmission path 6 Control part 601 Output control means 602 Monitoring means 603 Control target power supply part identification means 604 Protection control means 604a First protection control means 604b Second protection Control means P1-P3 Microwave power supply

Claims (9)

A plurality of microwave power supply units that output microwave power to be supplied to a common load; and a control unit that provides control information to the plurality of microwave power supply units, each microwave power supply unit being supplied to the load A microwave power supply device having a function of detecting traveling wave power and reflected wave power returning from a load and a function of controlling output in accordance with control information given from the control unit,
The controller is
Obtains information on the reflected wave power detected by each microwave power supply unit, monitors whether or not the reflected wave power exceeding the set value is detected at each microwave power supply unit, and reflects the reflected wave exceeding the set value Monitoring means for identifying a microwave power supply unit in which power is detected as a power supply unit to be protected;
Reflection detected by the protection target power supply unit when the output of each determination target power supply unit is temporarily stopped or lowered by using the plurality of microwave power supply units including the protection target power supply unit as sequential determination target power supply units. A determination target power supply unit that determines whether or not the wave power is reduced by a threshold value or more, and that reduces the reflected wave power detected by the protection target power supply unit when the output is stopped or reduced. A control target power supply unit specifying means for specifying the control target power supply unit;
Control information necessary for performing protection control for reducing the reflected wave power detected by the protection target power supply unit to be equal to or lower than the set value by stopping or reducing the output of the control target power supply unit. Protection control means to give to,
A microwave power supply device comprising: A plurality of microwave power supply units that output microwave power to be supplied to a common load; and a control unit that provides control information to the plurality of microwave power supply units, each microwave power supply unit being supplied to the load A microwave power supply device having a function of detecting traveling wave power and reflected wave power returning from a load and a function of controlling output in accordance with control information given from the control unit,
The controller is
Obtains information on the reflected wave power detected by each microwave power supply unit, monitors whether or not the reflected wave power exceeding the set value is detected at each microwave power supply unit, and reflects the reflected wave exceeding the set value Monitoring means for identifying a microwave power supply unit in which power is detected as a power supply unit to be protected;
Control information necessary for performing protection control to reduce the reflected wave power detected by the protection target power supply unit to a set value or less by stopping or reducing the output of the protection target power supply unit to the protection target power supply unit Providing first protection control means;
When the reflected wave power detected by the protection target power supply unit cannot be made to be equal to or lower than a set value even when the protection control by the first protection control unit is performed, other microwave power sources other than the protection target power supply unit Whether the reflected wave power detected by the protection target power supply unit is lower than the threshold when the output of each determination target power supply unit is temporarily stopped or reduced, with the unit as a sequential determination target power supply unit The control target power supply unit that determines the determination target power supply unit that has reduced the level of the reflected wave power detected by the protection target power supply unit when the output is stopped or reduced, as a control target power supply unit Specific means,
Control information necessary for performing protection control for reducing the reflected wave power detected by the protection target power supply unit to be equal to or lower than the set value by stopping or reducing the output of the control target power supply unit. A second protection control means for
A microwave power supply device comprising: A plurality of microwave power supply units that output microwave power to be supplied to a common load; and a control unit that provides control information to the plurality of microwave power supply units, each microwave power supply unit being supplied to the load A microwave power supply device having a function of detecting traveling wave power and reflected wave power returning from a load and a function of controlling output in accordance with control information given from the control unit,
The controller is
Obtains information on the reflected wave power detected by each microwave power supply unit, monitors whether or not the reflected wave power exceeding the set value is detected at each microwave power supply unit, and reflects the reflected wave exceeding the set value Monitoring means for identifying a microwave power supply unit in which power is detected as a power supply unit to be protected;
A reflected wave detected by the protection target power supply unit when the output of each determination target power supply unit is temporarily stopped or lowered by sequentially setting other microwave power supply units other than the protection target power supply unit as the determination target power supply units. Judgment target that determines whether or not the power level is lower than the threshold value, and reduces the reflected wave power level detected by the protection target power supply unit when the output is stopped or reduced. Control target power supply unit specifying means for specifying the power supply unit as a control target power supply unit;
In order to perform protection control to reduce the reflected wave power detected by the protection target power supply unit below the set value by stopping or reducing the output of the control target power supply unit specified by the control target power supply unit specifying means First protection control means for providing the control target power supply unit with necessary control information;
When the control target power supply unit is not specified by the control target power supply specifying unit, the reflected wave power detected by the protection target power supply unit by stopping or lowering the output of the protection target power supply unit is set to the set value. Second protection control means for performing protection control to be reduced below;
A microwave power supply device comprising:   The control unit outputs control information necessary for performing output return control for returning the output of the control target power supply unit to a specified level every time a predetermined time elapses while the protection control is being performed. 4. The microwave power supply apparatus according to claim 1, further comprising output return control means for supplying to the unit. The control unit comprises output control means for giving control information to each microwave power supply unit so as to keep the output of each microwave power supply unit at a target value,
The output control means increases the output of the microwave power supply unit other than the control target power supply unit when the protection control is being performed, thereby calculating the total amount of power given to the load from the plurality of microwave power supply units. The microwave power supply device according to claim 1, 2, 3 or 4, wherein control information is given to each microwave power source so as to perform control to maintain a target value. The control unit includes output control means for giving control information to each microwave power supply unit so that the output of each microwave power supply unit matches a target value,
The output control means calculates a total amount of power absorbed in the load from traveling wave power and reflected wave power detected by each of the plurality of microwave power supply units, and calculates the total amount of power calculated The microwave power supply device according to claim 1, 2, 3 or 4, wherein control information is given to each microwave power source so as to perform control to keep the value. The control unit and each microwave power supply unit are connected through a communication line,
The control unit is configured to send and receive signals necessary for operating each means through a communication line provided between each microwave power source unit,
The microwave power supply device according to any one of claims 1 to 6, wherein A control device that exchanges signals with each microwave power supply unit is provided in common to the plurality of microwave power supply units, and the control device is connected to each microwave power supply unit through a communication line,
The control unit is configured to transmit and receive signals necessary for operating each means via the control device;
The microwave power supply device according to any one of claims 1 to 6, wherein A control device for exchanging signals with another microwave power supply unit is provided in one microwave power supply unit selected from the plurality of microwave power supply units, and the one microwave power supply unit And other microwave power supplies are connected through a communication line,
The control unit is connected to the selected one microwave power supply unit through a communication line, and transmits and receives signals necessary for operating each means via the control device in the one microwave power supply unit. That is structured as
The microwave power supply device according to any one of claims 1 to 6, wherein

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