Plasma device

Abstract

The present invention provides a plasma device capable of making a notification corresponding to the generation status of a leakage current. The plasma device disclosed in the present invention comprises: an electrode that generates plasma by discharge; a power supply device that generates power to be supplied to the electrode; a power cable that supplies power from the power supply device to the electrode; a leakage detection device that detects the leakage current of the power cable; and a control device that performs a first notification based on a result of comparing the leakage current detected by the leakage detection device with a first threshold value, and performs a second notification based on a result of comparing the leakage current with a second threshold value.

Description

Technical Field

[0001] The present disclosure relates to plasma devices. Background Art

[0002] In the past, various plasma devices have been proposed that supply power to electrodes to generate discharge and generate plasma through the generated discharge. The plasma device of Patent Document 1 includes a vacuum gauge that detects the pressure in a processing chamber where plasma is generated. The plasma device changes the flow rate of the plasma generating gas supplied to the processing chamber based on the detection result of the vacuum gauge.

[0003] Prior art literature

[0004] Patent Document 1: Japanese Patent Application Publication No. 2004-79453 Summary of the invention

[0005] Problems to be solved by the invention

[0006] However, in such a plasma device, if a leakage current flowing from a power cable supplying power to an electrode to the ground is detected by a leakage detection device, power abnormality caused by leakage can be detected. On the other hand, for example, if a high voltage power is supplied by a power cable to generate plasma, noise is generated even during normal plasma generation, and the leakage detection device may detect the leakage current.

[0007] The present application has been made in view of the above-mentioned problems, and an object of the present application is to provide a plasma device capable of performing notification corresponding to the generation status of leakage current.

[0008] Technical solutions to solve problems

[0009] The present specification discloses a plasma device, which includes: an electrode that generates plasma by discharge; a power supply device that generates power to be supplied to the electrode; a power cable that supplies the power from the power supply device to the electrode; a leakage detection device that detects a leakage current of the power cable; and a control device that performs a first notification based on a result of comparing the leakage current detected by the leakage detection device with a first threshold value, and performs a second notification based on a result of comparing the leakage current with a second threshold value.

[0010] Effects of the Invention

[0011] According to the present disclosure, the control device performs different notifications according to the result of comparing the leakage current with the first threshold value and the result of comparing the leakage current with the second threshold value. Thus, notification corresponding to the generation status of the leakage current can be performed. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a diagram showing a plasma device.

[0013] Figure 2 is a perspective view of a plasma head.

[0014] Figure 3 This is a cross-sectional view obtained by cutting the plasma head along the X direction and the Z direction at the positions of the electrode and the plasma passage on the main body side.

[0015] Figure 4 yes Figure 3 Cross-sectional view at line AA.

[0016] Figure 5 It is a block diagram showing the structure of a plasma device.

[0017] Figure 6 It is a block diagram showing the structure of the leakage detection device.

[0018] Figure 7 It is a block diagram showing the configuration of the current sensor 111 and the gas supply unit 15B.

[0019] Figure 8 This is a diagram showing the conditions for detecting an abnormality and the contents of a notification process when an abnormality is detected.

[0020] Fig. 9 This is a graph showing the relationship between the leakage detection value in a normal state and each threshold value.

[0021] Fig.10 This is a graph showing the relationship between the leakage detection value at the time of abnormality and each threshold value.

[0022] Fig.11 This is a graph showing the relationship between the leakage detection value at the time of abnormality and each threshold value.

[0023] Fig.12 It is a graph showing the change of the pressure value of the process gas. DETAILED DESCRIPTION

[0024] Hereinafter, one method of implementing the present disclosure will be described in detail with reference to the accompanying drawings. Figure 1 As shown, the plasma device 10 of this embodiment includes: a plasma head 11, a robot 13 and a control box 15. The plasma head 11 is detachably mounted on the front end of the robot 13. The robot 13 is, for example, a serial link type robot (which can also be called a multi-jointed robot). The plasma head 11 can irradiate plasma gas while being mounted on the front end of the robot 13. The plasma head 11 can move in accordance with the driving of the robot 13, change its direction, etc., and can move three-dimensionally.

[0025] The control box 15 is mainly composed of a computer and generally controls the plasma device 10. The control box 15 includes a power supply unit 15A for supplying power to the plasma head 11 and a gas supply unit 15B for supplying a processing gas to the plasma head 11. The power supply unit 15A is connected to the plasma head 11 via a power cable 16 and a control cable 18. The power supply unit 15A generates a signal to the electrode 33 (see FIG. 1 ) of the plasma head 11 based on the control of the control box 15. Figure 3 ) supplies power to control the voltage applied to the electrode 33 and the heater 43 described later (see Figure 4 )’s temperature is controlled.

[0026] In addition, the gas supply unit 15B is connected to the plasma head 11 via a plurality of (four in the present embodiment) gas supply pipes 19. The gas supply unit 15B supplies the reaction gas (an example of a processing gas), the carrier gas (an example of a processing gas), and the heating gas (an example of a processing gas) described later to the plasma head 11 based on the control of the control box 15. The control box 15 controls the gas supply unit 15B to control the amount of gas supplied from the gas supply unit 15B to the plasma head 11. Furthermore, the plasma device 10 operates the robot 13 based on the control of the control box 15, and irradiates the plasma gas from the plasma head 11 to the object to be processed W placed on the workbench 17.

[0027] In addition, the control box 15 includes an operation unit 15C having a touch panel or various switches. The control box 15 displays various setting screens, operation states (for example, gas supply state, etc.) on the touch panel of the operation unit 15C. In addition, the control box 15 receives various information through operation input to the operation unit 15C.

[0028] The plasma head 11 is detachably mounted on a mounting plate 13A provided at the front end of the robot 13. Thus, the plasma head 11 can be replaced with a different type of plasma head 11. Figure 2 As shown, the plasma head 11 includes a plasma generating unit 21, a heating gas supply unit 23, and a nozzle 35. The plasma generating unit 21 receives a gas from a gas supply unit 15B (see FIG. Figure 1 ) is converted into plasma by the processing gas supplied by the plasma head 11, thereby generating plasma gas. Figure 4 ) The processing gas supplied from the gas supply unit 15B is heated to generate a heated gas. The temperature of the heated gas is, for example, 600° C. to 800° C. The plasma head 11 of this embodiment transmits the plasma gas generated in the plasma generating unit 21 together with the heated heated gas to the plasma head 11. Figure 1 The object W is ejected toward the plasma head 11. Figure 2The processing gas is supplied from the upstream side to the downstream side in the direction of the arrow shown. In addition, the plasma head 11 may not include the heater 43 for heating the heating gas. That is, the plasma apparatus of the present disclosure may not use the heating gas.

[0029] like Figure 2 As shown, on the connection surface 11A of the plasma head 11, the mounting portion 11B for mounting the power cable 16 is provided in the substantially central portion. In addition, a mounting portion 11C for mounting the control cable 18 is provided at one end of the connection surface 11A. In addition, a mounting portion 11D for mounting the gas supply pipe 19 is provided on the side opposite to the mounting portion 11C sandwiching the mounting portion 11B in the middle. The mounting portion 11D is connected to, for example, a mounting component 25 provided at the front end of the gas supply pipe 19. The mounting portion 11D and the mounting component 25 are, for example, so-called one-touch joints, and the gas supply pipe 19 is mounted on the plasma head 11 in a detachable manner.

[0030] like Figure 3 and Figure 4 As shown, the plasma generating unit 21 includes a head main body 31, a pair of electrodes 33, a nozzle 35, etc. Figure 3 2 is a cross-sectional view obtained by cutting at positions corresponding to a pair of electrodes 33 and a plurality of main body side plasma passages 71 described later. Figure 4 yes Figure 3 The head body 31 is formed of ceramic with high heat resistance, and a reaction chamber 37 for generating plasma gas is formed inside the head body 31. The pair of electrodes 33 are each in the shape of a cylinder, for example, and are fixed in a state where the front end thereof protrudes toward the reaction chamber 37. In the following description, the pair of electrodes 33 is sometimes simply referred to as the electrode 33. In addition, the direction in which the pair of electrodes 33 are arranged is referred to as the X direction, the axial direction of the cylindrical electrode 33 is referred to as the Z direction, and the direction orthogonal to the X direction and the Z direction is referred to as the Y direction for description.

[0031] The heating gas supply unit 23 includes a gas pipe 41, a heater 43, a connecting unit 45, etc. The gas pipe 41 and the heater 43 are mounted on the outer peripheral surface of the head body 31. Figure 4 The gas pipe 41 is covered with a cover 47 as shown. The gas pipe 41 is connected to the gas supply pipe 19 (see Figure 1 ) and connected to the gas supply unit 15B of the control box 15. A heating gas (e.g., air) is supplied from the gas supply unit 15B to the gas pipe 41. The heater 43 is installed in the middle of the gas pipe 41. The heater 43 heats the heating gas flowing in the gas pipe 41 to generate heated gas. In addition, the heater 43 is provided with a thermocouple 92 (see Figure 5 ).

[0032] like Figure 4 As shown, the connecting portion 45 connects the gas pipe 41 to the nozzle 35. When the nozzle 35 is mounted on the head body 31, the connecting portion 45 connects one end to the gas pipe 41 and connects the other end to the heating gas passage 51 formed in the nozzle 35. The heating gas is supplied to the heating gas passage 51 via the gas pipe 41.

[0033] like Figure 3 and Figure 4 As shown, the outer periphery of a part of the electrode 33 is covered by an electrode cover 53 made of an insulator such as ceramic. The electrode cover 53 is roughly hollow and cylindrical, and openings are formed at both ends in the length direction. The gap between the inner peripheral surface of the electrode cover 53 and the outer peripheral surface of the electrode 33 functions as a gas passage 55. The opening on the downstream side of the electrode cover 53 is connected to the reaction chamber 37. The lower end of the electrode 33 protrudes from the opening on the downstream side of the electrode cover 53.

[0034] In addition, a reaction gas flow path 61 and a pair of carrier gas flow paths 63 are formed inside the head body 31. The reaction gas flow path 61 is provided at a substantially central portion of the head body 31 and is supplied via a gas supply pipe 19 (see Figure 1 ) and connected to the gas supply unit 15B, so that the reaction gas supplied from the gas supply unit 15B flows into the reaction chamber 37. In addition, a pair of carrier gas flow paths 63 are arranged in the X direction at a position sandwiching the reaction gas flow path 61. The pair of carrier gas flow paths 63 are respectively connected to the pair of gas supply pipes 19 (see Figure 1 ) is connected to the gas supply unit 15B through each gas supply pipe 19, and the carrier gas is supplied from the gas supply unit 15B. The carrier gas flow path 63 allows the carrier gas to flow into the reaction chamber 37 through the gas passage 55. Figure 1 and Figure 2 The four gas supply pipes 19 shown are, for example, two gas supply pipes 19 for supplying carrier gas to a pair of carrier gas flow paths 63, one gas supply pipe 19 for supplying reaction gas, and a gas supply pipe 19 for supplying heating gas (heating gas before heating).

[0035] As the reaction gas (seed gas), oxygen (O2) can be used. The gas supply unit 15B, for example, allows a mixed gas of oxygen and nitrogen (N2) (e.g., dry air (Air)) to flow between the electrodes 33 of the reaction chamber 37 via the reaction gas flow path 61. Hereinafter, for convenience, the mixed gas is sometimes referred to as the reaction gas, and the oxygen is referred to as the seed gas. As the carrier gas, nitrogen can be used. The gas supply unit 15B allows the carrier gas to flow in from each gas passage 55 in a manner surrounding each electrode 33 in the pair of electrodes 33.

[0036] An alternating voltage is applied to the pair of electrodes 33 from the power supply unit 15A of the control box 15. By applying the voltage, for example, Figure 3As shown, in the reaction chamber 37, a simulated arc A is generated between the lower ends of a pair of electrodes 33. The simulated arc A is, for example, a method of causing discharge while limiting the current in the power supply unit 15A so that a large current does not flow as in a normal arc discharge. When the reaction gas passes through the simulated arc A, the reaction gas is plasmatized. Therefore, the pair of electrodes 33 generate discharges simulating the arc A, and the reaction gas is plasmatized to generate plasma gas.

[0037] In addition, a plurality of (six in this embodiment) main body side plasma passages 71 are formed in the downstream side portion of the reaction chamber 37 in the head main body 31. The upstream ends of the plurality of main body side plasma passages 71 form an opening in the reaction chamber 37, and the downstream ends of the plurality of main body side plasma passages 71 form an opening in the lower end surface of the head main body 31.

[0038] The nozzle 35 is formed of, for example, ceramics having high heat resistance. The nozzle 35 is fixed to the lower surface of the head body 31 by bolts 80. Therefore, the nozzle 35 can be detached from the head body 31 and can be changed to a different type of nozzle. A pair of grooves 81 with openings formed on the upper end surface are formed in the nozzle 35. The pair of grooves 81 are respectively connected to, for example, three main body side plasma passages 71 with openings formed on the lower end surface of the head body 31. In addition, a plurality of (in the present embodiment, 10) nozzle side plasma passages 82 are formed in the nozzle 35 that pass through the Z direction. The grooves 81 (for example, 5 each) are connected to the upper ends of the nozzle side plasma passages 82. In addition, Figure 3 and Figure 4 The shape and structure of the nozzle 35 shown are just examples.

[0039] In addition, a heating gas passage 95 is formed in the nozzle 35 so as to surround the nozzle-side plasma passage 82. The upper portion of the heating gas passage 95 is connected to the connection portion 45 of the heating gas supply unit 23 via the heating gas passage 51. The lower end of the heating gas passage 95 is opened at the lower surface of the nozzle 35.

[0040] With such a structure, the plasma gas generated in the reaction chamber 37 is ejected into the groove 81 through the main body side plasma passage 71 together with the carrier gas. In addition, the plasma gas diffuses inside the groove 81, and is ejected from the opening 82A at the lower end of the nozzle side plasma passage 82 through each plasma passage 82 in the plurality of nozzle side plasma passages 82. In addition, the heating gas supplied from the gas pipe 41 to the heating gas passage 51 flows in the heating gas passage 95. The heating gas functions as a shielding gas for protecting the plasma gas. The heating gas flows in the heating gas passage 95, and is ejected from the opening 95A at the lower end of the heating gas passage 95 along the ejection direction of the plasma gas. At this time, the heating gas is ejected in a manner surrounding the plasma gas ejected from the opening 82A of the nozzle side plasma passage 82. In this way, by ejecting the heated heating gas to the surroundings of the plasma gas after heating, the efficiency (wettability, etc.) of the plasma gas can be improved.

[0041] Next, the detailed structure of the control box 15 will be described. Figure 5 As shown, the control box 15 includes a controller 100, a drive circuit 105, a control circuit 106, a communication unit 107, a leakage detection device 110, a current sensor 111, a storage device 116, etc. in addition to the above-mentioned power supply unit 15A, a gas supply unit 15B, and an operating unit 15C. The controller 100 is mainly composed of a computer having a CPU, a ROM, a RAM, etc., which are not shown in the figure. The controller 100 uses the CPU to execute a program to control the power supply unit 15A, the drive circuit 105, the gas supply unit 15B, etc., thereby controlling the plasma head 11, the heating gas supply unit 23, etc. In addition, sometimes the controller 100 that uses the CPU to execute the program is recorded only by the device name. For example, the record "controller 100" sometimes means "controller 100 that uses the CPU to execute the program."

[0042] In addition, the controller 100 is connected to the operation unit 15C via the control circuit 106. The controller 100 changes the display of the touch panel of the operation unit 15C via the control circuit 106. In addition, the controller 100 receives the operation input to the operation unit 15C via the control circuit 106. In addition, the storage device 116 is composed of, for example, a hard disk drive, a RAM, a ROM, etc. The storage device 116 stores state information 118. The controller 100 stores, for example, information related to the state of the plasma device 10, information when an abnormality is detected, setting information of the plasma device 10, and the operation time of each device as the state information 118.

[0043] In addition, the communication unit 107 communicates with a communication device connected to a network not shown. The communication method is not particularly limited, and may be, for example, a LAN, serial communication, etc. In addition, the controller 100 may store the state information 118 in a server device on the network via the communication unit 107 instead of storing it in the storage device 116 in the control box 15.

[0044] The leakage detection device 110 is a device that detects leakage current of the power cable 16 that connects the power supply unit 15A and the plasma head 11 (electrode 33). Figure 6 1 shows the structure of the leakage detection device 110. Figure 6 As shown, the power cable 16 of this embodiment includes, for example, a first cable 16A, a second cable 16B, and a ground cable 16C. The front ends of the first cable 16A and the second cable 16B are connected to a pair of electrodes 33 (see Figure 3 ) are electrically connected respectively. Figure 1 As shown, the power cable 16 is installed on the robot 13. Therefore, loads such as bending, rotation, and tension are applied to the power cable 16 according to the movement of the robot 13, and there is a possibility that the power cable 16 may be damaged. Therefore, the plasma device 10 of this embodiment uses the leakage detection device 110 to detect abnormal current generated by damage to the power cable 16, etc.

[0045] like Figure 6 As shown, the leakage detection device 110 includes: a detection module 120 and a current transformer CT. The detection module 120 includes a comparison circuit 121 and a power supply circuit 122. The first cable 16A, the second cable 16B, and the grounding cable 16C of the power cable 16 are respectively covered with an insulator on the electric wire, for example. The first cable 16A, the second cable 16B, and the grounding cable 16C are shielded by a mesh-shaped conductive shielding member 145. The shielding member 145 is grounded via the grounding cable 16C.

[0046] The power supply unit 15A also includes AC power supplies 141 and 142. The AC power supply 141 generates AC power of a predetermined voltage and current value based on power supplied from a commercial power supply (not shown). The AC power supply 141 supplies the generated AC power to each of the pair of electrodes 33 via the first cable 16A and the second cable 16B.

[0047] The current transformer CT of the leakage detection device 110 is installed on the grounding cable 16C. The current transformer CT outputs a detection voltage corresponding to the current value of the leakage current flowing through the grounding cable 16C to the comparison circuit 121. The AC power supply 142 generates AC power (for example, AC200V) supplied to the power supply circuit 122 based on the AC power supplied from the AC power supply 141. The power supply circuit 122 outputs a driving voltage and a threshold voltage supplied to the comparison circuit 121 based on the AC power supplied from the AC power supply 142, and supplies the generated driving voltage and threshold voltage to the comparison circuit 121. The threshold voltage is an example of the first threshold and the second threshold of the present disclosure.

[0048] The comparison circuit 121 compares the detection voltage of the current transformer CT with the threshold voltage, and outputs the detection information SI indicating the comparison result to the controller 100. Here, when a short circuit or discharge occurs between the first cable 16A or the second cable 16B and the ground cable 16C, a leakage current flows from the AC power supply 141 to the ground. Therefore, the detection voltage of the current transformer CT changes. The comparison circuit 121 outputs the result of comparing the detection voltage of the changed current transformer CT with the threshold voltage to the controller 100 as the detection information SI.

[0049] In addition, when a short circuit or discharge occurs between the first cable 16A and the second cable 16B, a leakage current flows through the shielding member 145 due to electromagnetic induction or the like. In this case, the comparison circuit 121 also outputs the result of comparing the detection voltage of the fluctuating current transformer CT with the threshold value as the detection information SI to the controller 100. In this way, the leakage detection device 110 can detect not only the grounding of the first cable 16A or the second cable 16B, but also the short circuit or discharge between the first cable 16A and the second cable 16B.

[0050] In addition, when the power supply does not cause the above-mentioned short circuit or discharge, that is, when the power cable 16 is not damaged or cut off and the power required for plasma generation control is supplied by the power cable 16 in a normal state, leakage current flows in the shielding member 145 by electromagnetic induction or the like. In addition, when some noise is input to the shielding member 145, leakage current may also be generated. Even in such a normal state or in a case other than an abnormality of the plasma device 10, the leakage detection device 110 outputs the comparison result using the threshold value to the controller 100 as the detection information SI.

[0051] In addition, the structure of the leakage detection device 110 is not particularly limited. For example, the leakage detection device 110 may also be a structure that compares the current value of the leakage current flowing through the ground cable 16C with a threshold value. For example, the leakage detection device 110 performs AD conversion on the detection voltage corresponding to the current value flowing to the first cable 16A and the second cable 16B detected by the current transformer, and outputs the digital value representing the current value to the controller 100. The controller 100 may also compare the input current value with the threshold value. That is, the leakage detection device of the present disclosure may also be a structure that compares the current value. In this case, a predetermined current value can be set as the first threshold value and the second threshold value of the present disclosure. In addition, the comparison processing of the detected voltage value, current value and the threshold value may also be performed by the controller 100. In this case, the controller 100 is an example of the leakage detection device of the present disclosure.

[0052] In addition, the controller 100 of this embodiment determines the abnormality of the device based on the pressure value of the processing gas in addition to the detection information SI of the leakage current. Figure 7 As shown, the gas supply unit 15B includes a gas generator 109, a plurality of mass flow controllers 112 ( Figure 7 F1 to F5 in the figure), multiple pressure sensors 113 (the four white corners in the figure), etc. The gas generating device 109 is a device that supplies the supply sources of the reaction gas, the carrier gas, and the heating gas respectively. The gas generating device 109 supplies, for example, nitrogen (N2), oxygen (O2), and air (Air, dry air, etc.). The gas generating device 109 includes a compressor that serves as a supply source of air, a dryer for removing moisture from the air supplied from the compressor, a separation device that separates nitrogen and oxygen from the dry air, etc. In addition, the gas generating device 109 can also use air containing oxygen or dry air as oxygen of the seed gas of the reaction gas.

[0053] The gas generator 109 supplies reaction gas (oxygen, nitrogen), carrier gas (nitrogen), and heating gas (air) as process gases. For example, a plurality of mass flow controllers 112 are provided corresponding to each process gas, and control the flow rate of each process gas based on the control of the controller 100. Each mass flow controller 112 outputs the value (measured value) of the actual supplied flow rate after adjustment to the controller 100.

[0054] In addition, a plurality of pressure sensors 113 detect the pressure value of the processing gas whose flow rate is adjusted by each mass flow controller 112. In addition, the pressure sensor 113 detects the pressure value of the mixed gas in which the reaction gas (oxygen, nitrogen) is mixed in the mixer 115. Therefore, the pressure sensor 113 detects the pressure of each of the oxygen (O2) as the reaction gas (seed gas), the nitrogen (N2) mixed with the oxygen, and the mixed gas (dry air) after mixing. In addition, the pressure sensor 113 individually detects the pressure of the carrier gas flowing in the gas supply pipe 19 respectively connected to a pair of carrier gas flow paths 63. In addition, the pressure sensor 113 detects the pressure value of the heating gas (air before heating) supplied to the gas pipe 41. Each pressure sensor 113 outputs the detected pressure value to the controller 100. In addition, the controller 100 of this embodiment judges the abnormality of the device based on the leakage current (detection voltage) and the pressure value of the processing gas. The content of the judgment process will be described later.

[0055] In addition, the power supply unit 15A generates high-frequency AC power from a commercial power supply to the electrode 33, and supplies the generated AC power to the electrode 33. The current sensor 111 detects the current flowing in the first cable 16A and the second cable 16B for supplying power from the power supply unit 15A to the electrode 33. The current sensor 111 includes, for example, a current transformer, performs AD conversion on a detection voltage corresponding to the current value flowing through the first cable 16A and the second cable 16B detected by the current transformer, and outputs a digital value corresponding to the current value to the controller 100.

[0056] In addition, if Figure 5 As shown in FIG. 1 , the heater 43 and the thermocouple 92 installed near the heater 43 are electrically connected to the drive circuit 105. The drive circuit 105 outputs a temperature corresponding to the output value of the thermocouple 92 to the controller 100. The drive circuit 105 controls the heating temperature of the heater 43 so as to achieve the target temperature instructed by the controller 100 based on the output value of the thermocouple 92. The temperature sensor 114 is provided in the plasma head 11, for example. The temperature sensor 114 has, for example, a thermocouple, detects the temperature of the plasma gas, and outputs the detected temperature to the controller 100.

[0057] Next, the notification process performed by the controller 100 of the present embodiment will be described. When the controller 100 receives an instruction to start plasma processing via the touch panel of the operation unit 15C, for example, it starts plasma generation control. In the plasma generation control, the controller 100 controls the power supply unit 15A to start supplying a predetermined power to the electrode 33. In the following description, the start of supplying power from the power supply unit 15A to the electrode 33 is referred to as "plasma ON".

[0058] In addition, when the plasma is turned on, the controller 100 causes the gas supply unit 15B to start supplying the processing gas (carrier gas, reaction gas, heating gas). The gas supply unit 15B starts supplying the processing gas at a predetermined gas flow rate and pressure value set in advance. In addition, the controller 100 controls the drive circuit 105 to control the heating temperature of the heater 43 to a predetermined temperature.

[0059] In addition, when the plasma is set to ON, the controller 100 stores the state information 118 related to the state of the plasma device 10 in the storage device 116. In addition, the controller 100 determines the occurrence of an abnormality in the device. When the controller 100 detects an abnormality in the device, for example, it stops the supply of power to the electrode 33, stops the supply of the processing gas, stops the operation of the heating gas supply unit 23, and ends the plasma generation control. As a result, the plasma generation of the plasma device 10 stops. When the controller 100 detects an abnormality and ends the plasma generation control, it displays the information of the detected abnormality on the screen of the operation unit 15C.

[0060] Figure 8 Indicates the conditions that the controller 100 determines as abnormal and the content of the notification process when the abnormality is detected. In the following description, the detection voltage value detected by the leakage detection device 110 is referred to as the leakage detection value. First, the top number 1 is the case where the leakage detection value detected by the leakage detection device 110 is greater than the maximum threshold value TH1. The second number 2 is the case where the leakage detection value detected by the leakage detection device 110 is greater than the upper limit threshold value TH2. Fig. 9 The controller 100 of the present embodiment uses the maximum threshold TH1, the upper threshold TH2, the lower threshold TH3, and the lowest threshold TH4 to determine whether the leakage detection value is abnormal.

[0061] The maximum threshold TH1 is, for example, a value that can determine the leakage detection value (detection voltage value corresponding to the leakage current) detected when the power cable 16 is cut or damaged and a short circuit or discharge occurs between the first cable 16A or the second cable 16B and the ground cable 16C. The maximum threshold TH1 is, for example, a voltage value applied to the electrode 33 during discharge, or a value obtained by subtracting the power loss of the power cable 16 or the ground cable 16C from the voltage value. In addition, the upper threshold TH2 is a value smaller than the maximum threshold TH1. For example, in the event of a short circuit or discharge between the first cable 16A and the second cable 16B, or in the event of a slight cut in the power cable 16, a leakage current flows in the shielding component 145 due to electromagnetic induction, etc. The upper threshold TH2 is a value that can detect an increase (abnormality) in the leakage detection value that has not increased to such a maximum threshold TH1. Fig. 9As shown in the solid line waveform 150 in FIG. 1 , when the power cable 16 is not damaged or cut and power can be supplied normally, the leakage detection value gradually increases from when the plasma is turned on and stabilizes near the reference value Vs. The reference value Vs is a leakage detection value generated by electromagnetic induction and noise during normal power supply.

[0062] on the other hand, Fig.10 Indicates the relationship between the leakage detection value and each threshold value during an abnormality. The dotted waveform 151 is a case where the leakage detection value is above the upper threshold value TH2, indicating that the leakage detection value increases due to the occurrence of certain abnormalities from the state where the leakage detection value is stable at the reference value Vs. As shown in the waveform 151, when a discharge occurs between the first and second cables 16A and 16B when the leakage detection value is the reference value Vs (for example, during plasma irradiation), the leakage detection value increases from the reference value Vs to become above the upper threshold value TH2. In the case where the first and second cables 16A and 16B are not completely cut off, for example, only a part of the power supplied from the power supply unit 15A flows to the ground cable 16C, and the leakage detection value does not increase to the maximum threshold value TH1, but is less than the maximum threshold value TH1. In addition, similar to the case where an abnormality occurs after plasma ON, for example, in the case where there is damage to the power cable 16 before plasma ON, the leakage detection value increases to above the upper threshold value TH2 after plasma ON.

[0063] When the controller 100 detects that the leakage detection value is above the upper threshold value TH2, Figure 8 As shown, the touch panel of the operation unit 15C displays the possibility that the power cable 16 is cut. As described above, the upper threshold TH2 is a threshold for warning when an increase in the leakage detection value is detected for some reason, although it is unclear whether the power cable 16 is actually cut. Therefore, the controller 100 displays a confirmation message such as "Please confirm because there is a possibility that damage has occurred somewhere in the power cable 16" on the operation unit 15C. And, for example, the user confirms the state of the plasma device 10 and inputs the operation to the operation unit 15C to end the confirmation. The controller 100 may also resume the plasma generation control when receiving the operation input to the operation unit 15C.

[0064] on the other hand, Fig.10The solid line waveform 153 in represents a case where the leakage detection value is above the maximum threshold value TH1. As shown in the waveform 153, when the power cable 16 is cut off while the leakage detection value is the reference value Vs, the leakage detection value increases from the reference value Vs, exceeds the upper limit threshold value TH2 and becomes above the maximum threshold value TH1. For example, in the case where a short circuit occurs between the first cable 16A and the grounding cable 16C, most of the power supplied from the AC power supply 141 to the first cable 16A flows to the ground as a leakage current via the grounding cable 16C. Therefore, the possibility of the leakage detection value increasing to the maximum threshold value TH1 becomes high. Similarly, for example, in the case where the power cable 16 is cut off before the plasma is turned on, the leakage detection value also increases to the maximum threshold value TH1 after the plasma is turned on.

[0065] When the controller 100 detects that the leakage detection value is above the maximum threshold value TH1, Figure 8 As shown, the fact that the power cable 16 has been cut is displayed on the touch panel of the operation unit 15C. As described above, when the leakage detection value is greater than the maximum threshold value TH1, the possibility of the power cable 16 being cut is extremely high. Therefore, the controller 100 displays a warning message such as "Emergency stop due to damage to a certain part of the power cable 16" on the operation unit 15C. In this case, the controller 100 stops the power supply of the power supply unit 15A until the cause of the leakage abnormality is reliably solved, such as when the replacement of the power cable 16 is detected, when the maintenance worker performs an operation input for confirming the operation using the operation unit 15C, etc.

[0066] Therefore, in the present embodiment, as a first threshold, an upper threshold TH2 greater than the leakage detection value (current value of leakage current, current value equivalent to the reference value Vs) detected by the leakage detection device 110 in a state where plasma is normally generated is included. In addition, as a second threshold, a maximum threshold TH1 greater than the upper threshold TH2 is included. When the leakage detection value becomes greater than the upper threshold TH2, the controller 100 notifies the possibility of leakage of the power cable 16 (an example of a first notification). In addition, when the current value of the leakage current becomes greater than the maximum threshold TH1, the controller 100 notifies the disconnection of the power cable 16 (an example of a second notification).

[0067] The leakage current (reference value Vs) based on the noise (induced current) etc. generated by the power supply in the state of normal plasma generation is set as a reference, and the upper limit threshold value TH2 larger than the leakage current is set. As a result, the possibility of leakage such as a short circuit of the power cable 16 can be notified. In addition, by setting the maximum threshold value TH1 larger than the upper limit threshold value TH2, a state where the occurrence of leakage abnormality is extremely high, such as a situation where the power cable 16 is completely cut off and abnormal discharge occurs in the middle of the power cable 16, can be detected and notified. Therefore, the possibility of leakage and reliable leakage notification can be performed by the upper limit threshold value TH2 and the maximum threshold value TH1.

[0068] in addition, Figure 8 Numbers 3 and 4 in the figure represent the case where the leakage detection value is below the minimum threshold value TH4. The controller 100 of this embodiment performs the judgment of leakage anomaly based on the minimum threshold value TH4 when the plasma is ON. The minimum threshold value TH4 is, for example, a threshold value for detecting anomalies in which no leakage current flows (the leakage detection value does not increase) or the leakage current is extremely small. For example, in the case where the grounding cable 16C is forgotten to be connected to the ground wire of the plasma device 10, the grounding cable 16C is cut off, the grounding cable 16C falls off, etc., if a fault related to the leakage detection device 110 occurs, the leakage detection value may not increase or may be extremely small. The minimum threshold value TH4 is a value that can detect such a state in which the leakage detection value does not increase, for example, 0V (if it is a current, it is 0A) or a value close to 0V.

[0069] Fig.11 The waveform 155 in FIG. 1 is a case where the leakage detection value becomes less than the minimum threshold value TH4, indicating the state when the plasma is turned on. As shown in the waveform 155, in the case where the grounding cable 16C is forgotten to be installed, the leakage detection value does not increase from the time of plasma turning on, but is lower than the minimum threshold value TH4, or is lower than the lower limit threshold value TH3 described later and is near the minimum threshold value TH4.

[0070] On the other hand, even if the ground cable 16C is connected normally, for example, when the process gas is not supplied and the discharge of the electrode 33 does not occur, or when the discharge does not occur for some reason, the leakage detection value may not increase. Specifically, the leakage detection value may decrease due to various reasons such as damage to the gas supply pipe 19, failure of the gas supply unit 15B, deterioration of the electrode 33, damage to the reaction chamber 37, etc.

[0071] Fig.12Indicates the change in the pressure value of the processing gas from the plasma ON time to the plasma irradiation time. Here, for example, as for the pressure value of the processing gas detected by the pressure sensor 113, as long as there is no abnormality in the generation state of the simulated arc A, the pressure value increases in the same manner from the time when the plasma is ignited and the plasma irradiation starts, regardless of the type of carrier gas, reaction gas, and heating gas. Therefore, in the following description, various gases are collectively referred to as processing gases for description unless they need to be specifically distinguished. Fig.12 As shown in the waveform 157 in FIG. 1 , the pressure value of the pressure of the processing gas whose flow rate and flow velocity are adjusted by the mass flow controller 112 detected by the pressure sensor 113 gradually increases from the time when the plasma is turned on. Since the supply of each processing gas starts from the time when the plasma is turned on, the pressure value gradually increases. The pressure value is saturated at the reference pressure value Ps, for example. Then, a simulated arc A is generated between the electrodes 33, and the temperature of the plasma head 11 rises. In addition, the temperature of the plasma head 11 also rises due to the heating of the heating gas. The pressure value gradually increases from the reference pressure value Ps over time.

[0072] Furthermore, if the gas supply pipe 19 is damaged or the gas supply unit 15B fails, Fig.12 As shown in the dotted waveform 159 in , a decrease in the pressure value occurs. The extent to which the pressure value decreases depends on the time point when the abnormality occurs, the type and scale of the abnormality that occurs, etc. For example, if the pressure value decreases before the plasma is ignited, it may not rise to the reference pressure value Ps (refer to the waveform 159 on the lower side). Alternatively, if the pressure value decreases after the plasma is ignited, it may not rise to the predetermined threshold pressure value Pth (refer to the waveform 159 on the upper side). The threshold pressure value Pth is, for example, a threshold value set between the reference pressure value Ps and the maximum pressure value during plasma irradiation. Therefore, by presetting such a reference pressure value Ps and threshold pressure value Pth, it is possible to detect an abnormality in which the pressure value does not rise.

[0073] Therefore, if Figure 8As shown in No. 3 in the figure, when the controller 100 detects that the leakage detection value is below the minimum threshold value TH4 and the pressure value has not risen to the reference pressure value Ps, for example, when the plasma is on, the subject that the plasma is not irradiated is displayed on the operating unit 15C. The plasma on mentioned here refers to, for example, the period from plasma on to plasma ignition. Alternatively, the plasma on time may also be the period from plasma on to stable irradiation of plasma gas. In addition, the subject that the plasma is not irradiated mentioned here is not only a subject that notifies of the abnormality that plasma is not generated, but also an example of a display for notifying abnormalities other than the abnormalities related to the leakage detection device 110, such as damage to the above-mentioned gas supply pipe 19, failure of the gas supply unit 15B, deterioration of the electrode 33, damage to the reaction chamber 37, etc. On the other hand, as Figure 8 As shown in number 4, when the plasma is on, if the controller 100 detects that the leakage detection value is below the minimum threshold value TH4 and the pressure value rises to above the reference pressure value Ps (rises to a normal value), the operating unit 15C displays the main point that there is an abnormality in the grounding cable 16C and the shielding component 145 (an example of an abnormality related to the leakage detection device 110).

[0074] in addition, Figure 8 Numbers 5 and 6 in the table represent the case where the leakage detection value is below the lower threshold TH3. The controller 100 of the present embodiment performs a judgment of leakage abnormality based on the lower threshold TH3 after starting plasma irradiation. Here, after starting plasma irradiation refers to, for example, the period after plasma ignition. Alternatively, after starting plasma irradiation may also refer to the period after the plasma gas is stably irradiated. The lower threshold TH3 is a value smaller than the reference value Vs at which normal plasma irradiation can be performed without the above-mentioned various abnormalities, and is a value larger than the minimum threshold TH4. For example, the upper threshold TH2 is a value obtained for the reference value Vs+X[V]. And, the lower threshold TH3 is a value obtained for the reference value Vs-X[V]. That is, the upper threshold TH2 and the lower threshold TH3 are, for example, values ​​obtained by adding or subtracting a predetermined value (X[V]) from the reference value Vs as the central value.

[0075] Similar to the minimum threshold TH4, if leakage abnormality occurs after the plasma irradiation is started, the leakage detection value may decrease. In addition, after the plasma irradiation is started, if the gas supply pipe 19 is damaged or the supply of the processing gas is stopped, the leakage detection value may also decrease (refer to Fig. 9 The dotted waveform 161 in FIG. 16A shows that Figure 8 As shown in No. 5 in FIG. 5 , after the controller 100 starts irradiating the plasma, for example, when it is detected that the leakage detection value drops below the lower limit threshold TH3 and the pressure value drops to the threshold pressure value Pth (refer to Fig.12 ), the fact that plasma is not irradiated is displayed on the operation unit 15C. Thus, when an abnormality such as plasma extinction, damage to the gas supply pipe 19, failure of the gas supply unit 15B, degradation of the electrode 33, damage to the reaction chamber 37, etc. occurs during plasma irradiation, it can be notified as a plasma irradiation abnormality. In addition, the controller 100 can also use the reference pressure value Ps (refer to Fig.12 ) to judge the decrease of pressure value. On the other hand, Figure 8 As shown in No. 6, after the controller 100 starts plasma irradiation, if it is detected that the leakage detection value drops below the lower limit threshold value TH3 and the pressure value is maintained at a normal value above the threshold pressure value Pth, the operating unit 15C displays the main point that there is an abnormality in the grounding cable 16C and the shielding component 145 (an example of an abnormality related to the leakage detection device 110).

[0076] Therefore, in this embodiment, as the first threshold, a lower limit threshold TH3 (see Fig. 9 ). In addition, as the second threshold, a minimum threshold TH4 that is smaller than the lower limit threshold TH3 is included. When the controller 100 starts to supply power to the electrode 33 (when the plasma is ON), if the leakage detection value is less than the minimum threshold TH4 and the pressure value of the processing gas detected by the pressure sensor 113 has not risen to a predetermined pressure value (threshold pressure value Pth, reference pressure value Ps), the controller 100 notifies an abnormality that the plasma is not irradiated (an example of a second notification). In addition, when the controller 100 starts to supply power to the electrode 33, if the leakage detection value is less than the minimum threshold TH4 and the pressure value of the processing gas detected by the pressure sensor 113 has risen to a predetermined pressure value, the controller 100 notifies an abnormality related to the leakage detection device 110 (an example of a second notification).

[0077] When power starts to be supplied to the electrode 33 (after plasma is turned on), the current value of the leakage current exceeds the minimum threshold value TH4 from zero, and further exceeds the lower limit threshold value TH3, becoming a normal current value (see Fig. 9150 in FIG. 15). In other words, when the power supply starts, the minimum threshold value TH4 is used, thereby detecting an abnormality earlier than when the lower limit threshold value TH3 is used. Therefore, when the power supply starts, the controller 100 notifies the abnormality that the plasma is not irradiated when the leakage detection value is less than the minimum threshold value TH4 and the pressure value does not rise. Thus, in the case of an abnormality that the plasma is not ignited or an abnormality that the processing gas is not supplied, it is possible to notify the abnormality. In addition, when the power supply starts, the controller 100 notifies the abnormality related to the leakage detection device 110 when the leakage detection value is less than the minimum threshold value TH4 and the pressure value rises. Thus, in the case of abnormalities such as a connection error of the leakage detection device 110 and a disconnection of the grounding cable 16C, it is possible to notify the abnormality.

[0078] In addition, during the plasma irradiation period after the plasma irradiation is started, when the leakage detection value is below the lower limit threshold value TH3 and the pressure value of the processing gas detected by the pressure sensor 113 drops to a predetermined pressure value (threshold pressure value Pth or reference pressure value Ps), the controller 100 notifies the abnormality that the plasma is not irradiated (an example of the first notification, Figure 8 5 in the figure). In addition, during the plasma irradiation, when the leakage detection value is below the lower limit threshold value TH3 and the pressure value of the processing gas detected by the pressure sensor 113 has not dropped to a predetermined pressure value, the controller 100 notifies an abnormality related to the leakage detection device 110 (an example of a first notification, Figure 8 6 in the figure).

[0079] Once the plasma irradiation starts, the current value and pressure value of the leakage current become values ​​within a certain range. In addition, when an abnormality occurs, the current value or voltage value is lower than the lower threshold value TH3, and then lower than the minimum threshold value TH4. In other words, after the plasma irradiation starts, by using the lower threshold value TH3, the abnormality can be detected earlier than when the minimum threshold value TH4 is used. Therefore, during the plasma irradiation, when the leakage detection value is below the lower threshold value TH3 and the pressure value is reduced, the controller 100 notifies the abnormality of not irradiating the plasma. Thus, in the case of an abnormality of plasma interruption or an abnormality of stopping the supply of the processing gas, the abnormality can be notified. In addition, during the plasma irradiation, when the leakage detection value is below the lower threshold value TH3 and the pressure value is not reduced, the controller 100 notifies the abnormality related to the leakage detection device 110. Thus, in the case of abnormalities such as a failure of the leakage detection device 110 and the cutting of the grounding cable 16C, the abnormality can be notified.

[0080] In addition, the controller 100 of this embodiment executes notifications No. 5 and No. 6 (an example of the first notification) and notifications No. 3 and No. 4 (an example of the second notification) based on the pressure value of the processing gas detected by the pressure sensor 113 and the leakage detection value (the voltage value and current value of the leakage current). The pressure value detected by the pressure sensor 113 rises at the time point such as the start of the supply of the processing gas and the ignition of the plasma. Therefore, the controller 100 determines the generation status of the leakage current by combining the pressure value of the processing gas with the voltage value and current value of the leakage current, thereby being able to distinguish the generation status in more detail and change the notification content.

[0081] In addition, the plasma device 10 of the present embodiment includes a conductive shielding member 145 for shielding the power cable 16 and a grounding cable 16C for grounding the shielding member 145. The leakage detection device 110 detects the leakage current flowing through the grounding cable 16C. Thus, the leakage detection device 110 can detect the leakage current flowing from the shielding member 145 for shielding the power cable 16 to the ground. In the shielding member 145, the leakage current may flow due to various noises. Therefore, the controller 100 can make a notification corresponding to the generation status of the leakage current by comparing the detected leakage current with the first and second thresholds (maximum threshold TH1, upper threshold TH2, lower threshold TH3, and lowest threshold TH4).

[0082] in addition, Figure 8 An example of processing for notifying an abnormality based on a detected voltage value based on a leakage current and a pressure value of a processing gas is shown. The controller 100 may also notify an abnormality based on other information (the flow rate of the mass flow controller 112 or the current value detected by the current sensor 111). In addition, the controller 100 may also determine an abnormality and change the notification content by combining other information in addition to the detected voltage value based on the leakage current and the pressure value of the processing gas. In addition, the controller 100 may also set various thresholds for the current value of the leakage current to determine an abnormality, similarly to the voltage value of the leakage current.

[0083] Incidentally, in the above-mentioned embodiment, the power supply unit 15A is an example of a power supply device. The gas supply unit 15B is an example of a gas supply device. The carrier gas, the reaction gas, and the heating gas are examples of process gases. The controller 100 is an example of a control device. The pressure sensor 113 is an example of a pressure detection device. The upper threshold TH2 and the lower threshold TH3 are examples of first thresholds. The maximum threshold TH1 and the minimum threshold TH4 are examples of second thresholds.

[0084] According to the above-described embodiment, the following effects are achieved.

[0085] In one mode of the present embodiment, the controller 100 of the plasma device 10 performs the control based on the result of comparing the leakage detection value detected by the leakage detection device 110 with the first threshold value (upper threshold value TH2, lower threshold value TH3). Figure 8 The controller 100 performs notifications 2, 5, and 6 (an example of the first notification) based on the result of comparing the leakage detection value with the second threshold value (maximum threshold value TH1, minimum threshold value TH4) to perform notifications 1, 3, and 4 (an example of the second notification).

[0086] Thus, the leakage current of the power cable 16 that supplies power to the electrode 33 is monitored by the leakage detection device 110. The controller 100 performs different notifications according to the result of comparing the leakage current with the first threshold value and the result of comparing the leakage current with the second threshold value. Thus, the first and second threshold values ​​can be used to determine the generation conditions of leakage currents such as leakage currents generated by noise during normal power supply, leakage currents generated by short circuits and cutoffs of the power cable 16, and leakage currents detected due to faults related to the leakage detection device 110, and different notifications can be performed. Therefore, notifications corresponding to the generation conditions of the leakage current can be performed.

[0087] In addition, the present disclosure is not limited to the above-described embodiment, and it goes without saying that various improvements and changes can be made within the scope not departing from the gist of the present disclosure.

[0088] For example, the controller 100 uses the maximum threshold TH1, the upper threshold TH2, the lower threshold TH3, and the lowest threshold TH4 to determine the leakage anomaly, but is not limited to this. For example, the controller 100 can also determine the leakage anomaly only by the combination of the maximum threshold TH1 and the upper threshold TH2, or only by the combination of the lower threshold TH3 and the lowest threshold TH4.

[0089] In addition, the controller 100 may not use the pressure value of the processing gas, but only use the first threshold value and the second threshold value to determine the leakage abnormality.

[0090] In the above embodiment, the controller 100 performs the processing displayed on the operation unit 15C as the first and second notifications of the present disclosure, but the present invention is not limited thereto. For example, the controller 100 may perform the first and second notifications by lighting a display lamp such as an LED, playing a warning sound from a speaker, etc.

[0091] In addition, the power supply unit 15A and the gas supply unit 15B may be devices separate from the control box 15 .

[0092] In addition, the power cable 16 is preferably covered with a flame retardant material.

[0093] Description of Reference Numerals

[0094] 10 plasma device, 15A power supply unit (power supply device), 15B gas supply unit (gas supply device), 16 power cable, 16C ground cable, 33 electrode, 100 controller (control device), 110 leakage detection device, 113 pressure sensor (pressure detection device), 145 shielding component, TH1 maximum threshold value (second threshold value), TH2 upper threshold value (first threshold value), TH3 lower threshold value (first threshold value), TH4 minimum threshold value (second threshold value).

Claims

1. A plasma device comprising: Electrodes, which generate plasma by discharge; a power supply device for generating electric power to be supplied to the electrodes; a power cable for supplying the power from the power supply device to the electrodes; A leakage detection device for detecting leakage current of the power cable; and a control device that performs a first notification based on a result of comparing the leakage current detected by the leakage detection device with a first threshold value, and performs a second notification based on a result of comparing the leakage current with a second threshold value, The first threshold value includes an upper threshold value, and the upper threshold value is greater than the current value of the leakage current detected by the leakage detection device in a state where plasma is normally generated. The second threshold comprises a maximum threshold greater than the upper threshold, When the current value of the leakage current is above the upper threshold, the control device notifies the leakage abnormality that the power cable may be cut off as the first notification, and when the current value of the leakage current is above the maximum threshold, the control device notifies the leakage abnormality that the power cable is cut off as the second notification.

2. The plasma device according to claim 1, wherein: The plasma device comprises: a gas supply device for supplying a processing gas for plasma irradiation; and a pressure detection device for detecting the pressure of the processing gas supplied from the gas supply device, The control device performs the first notification and the second notification based on the pressure value of the process gas and the current value of the leakage current detected by the pressure detection device.

3. The plasma device according to claim 2, wherein: The first threshold value includes a lower limit threshold value, and the lower limit threshold value is smaller than the current value of the leakage current detected by the leakage detection device in a state where plasma is normally generated. The second threshold comprises a lowest threshold smaller than the lower threshold, When power is started to be supplied to the electrode, when the current value of the leakage current is below the minimum threshold value and the pressure value of the processing gas detected by the pressure detection device has not risen to a predetermined pressure value, the control device notifies an abnormality that plasma is not irradiated as the second notification, When power starts to be supplied to the electrode, when the current value of the leakage current is below the minimum threshold and the pressure value of the processing gas detected by the pressure detection device rises to a predetermined pressure value, the control device notifies the abnormality related to the leakage detection device as the second notification.

4. The plasma device according to claim 3, wherein: During the plasma irradiation after the plasma irradiation is started, when the current value of the leakage current is below the lower limit threshold and the pressure value of the processing gas detected by the pressure detection device decreases to a predetermined pressure value, the control device notifies the abnormality of non-irradiation of plasma as the first notification, During plasma irradiation after the start of plasma irradiation, when the current value of the leakage current is below the lower limit threshold and the pressure value of the processing gas detected by the pressure detection device has not dropped to a predetermined pressure value, the control device notifies the abnormality related to the leakage detection device as the first notification.

5. The plasma device according to any one of claims 1 to 4, wherein: The plasma device comprises: A conductive shielding component for shielding the power cable; and A grounding cable is used to ground the shielding component. The leakage detection device detects the leakage current flowing through the ground cable.

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