JP2021096987A - Discharge detection system and charged particle beam device - Google Patents

Abstract

To provide a cable, a discharge detection system and a charged particle beam device, capable of identifying a discharge location.SOLUTION: A charged particle beam device includes: a charged particle gun 201 emitting charged particle beams; a cable including a power line 30 supplying power from a voltage source HVPS to the charged particle gun 201, optical fiber lines 40a, 40b provided along the power line 30 and transmitting discharge light emission in the charged particle gun 201 or the power line 30 to a voltage source side, and an insulator 50 covering the power line 30 and the optical fiber lines 40a, 40b; the voltage source HVPS connected to the cable, and allowing light from the optical fiber lines 40a, 40b to pass, the voltage source supplying voltage to the power line 30; and a detector PMT receiving light from the voltage source HVPS to detect discharge light emission in the charged particle gun 201 or the power line 30.SELECTED DRAWING: Figure 3

Description

The present embodiment relates to a discharge detection system and a charged particle beam device.

The charged particle beam device applies a high voltage from a high voltage power source to the turret via a cable to generate a charged particle beam from the turret. However, apart from the generation of the charged particle beam, an unintended discharge may occur in a high voltage power supply, a cable, a turret, or the like. Conventionally, it has been difficult to identify where such a discharge occurs in a high-voltage power supply, a cable, a turret, or the like.

Japanese Unexamined Patent Publication No. 10-270426 Japanese Unexamined Patent Publication No. 07-110300

Provided are a discharge detection system and a charged particle beam device capable of easily identifying a discharge location.

The charged particle beam device according to the present embodiment is provided along a charged particle gun that emits a charged particle beam, a power supply line that supplies power from a voltage source to the charged particle gun, and a charged particle gun or a power supply line. It is connected to a cable or cable provided with a first optical fiber line that transmits discharge light emission to the voltage source side and an insulator that covers the power supply line and the first optical fiber line, and passes light from the first optical fiber line. It is equipped with a voltage source that supplies a voltage to the power supply line, and a detector that receives light from the voltage source and detects discharge light emission in the charged particle gun or the power supply line. The discharge detection system according to the present embodiment includes a power supply line that supplies power from the voltage source to the load, and a first optical fiber line that is provided along the power supply line and transmits discharge light emission in the load or power supply line to the voltage source side. , A voltage source connected to a cable with an insulator covering the power supply line and the first optical fiber line, passing light from the first optical fiber line, and supplying a voltage to the power supply line, and a pressure. It is equipped with a detector that receives the light from the source and detects the discharge light emission in the load.

The figure which shows an example of the structure of the electron beam drawing apparatus by 1st Embodiment. The schematic diagram which shows an example of the structure of the electron gun by 1st Embodiment. The schematic cross-sectional view which shows the structural example of a cable, an electron gun and a high voltage power source. Schematic cross-sectional view showing a configuration example of a cable. The schematic cross-sectional view which shows the structural example of the discharge detection system according to 2nd Embodiment. The schematic cross-sectional view which shows the structural example of the charged particle beam apparatus according to 3rd Embodiment.

Hereinafter, embodiments according to the present invention will be described with reference to the drawings. The present embodiment is not limited to the present invention. The drawings are schematic or conceptual, and the ratio of each part is not always the same as the actual one. In the specification and the drawings, the same elements as those described above with respect to the existing drawings are designated by the same reference numerals, and detailed description thereof will be omitted as appropriate.

In the embodiment shown below, the configuration of an electron beam drawing apparatus including an electron gun that emits an electron beam will be described. The present embodiment is not limited to the electron beam drawing apparatus, and can be applied to other charged particle beam apparatus such as a mask inspection apparatus. Further, the charged particle beam is not limited to the electron beam, and may be another charged particle beam such as an ion beam.

(First Embodiment)
FIG. 1 is a diagram showing an example of the configuration of the electron beam drawing apparatus according to the first embodiment. The electron beam drawing apparatus 100 is used for manufacturing a photomask having a fine circuit pattern and drawing on a wafer such as a silicon wafer. In FIG. 1, the electron beam drawing device (hereinafter referred to as drawing device) 100 is an example of a variable molding type electron beam drawing device, and includes a drawing unit 150 and a control calculation unit 160.

The drawing unit 150 includes an electronic lens barrel 102 and a drawing chamber 103.

The inside of the electron barrel 102 can be kept in a substantially vacuum atmosphere. The electron barrel 102 includes an electron gun 201, an illumination lens 202, a blanking deflector 212, a blanking aperture 214, a molded aperture 203, 206, a projection lens 204, a molded deflector 205, an objective lens 207, and a deflector 208, 209. It is equipped with an electron gun chamber 217.

The electron gun 201 as a charged particle gun is housed in an electron gun chamber 217 as a chamber, and generates an electron beam as a charged particle beam. The electron gun chamber 217 is depressurized by a vacuum pump (not shown).

The illumination lens 202, the projection lens 204, and the objective lens 207 are all electromagnetic lenses that change the excitation to converge the electron beam and adjust the imaging position (irradiation position). As shown in FIG. 1, these are arranged in the axial direction of the electron beam 200 from one end on the upstream side where the electron gun 201 is arranged toward the downstream side where the stage 105, which will be described later, is located.

The illumination lens 202 illuminates the molded aperture 203 with the electron beam 200 emitted from the electron gun 201. The electron beam 200 formed by the forming aperture 203 is further projected onto the forming aperture 206 by the projection lens 204. The position of the molded aperture image on the molded aperture 206 is controlled by the molding deflector 205. This changes, for example, the shape and dimensions of the electron beam. The electron beam 200 that has passed through the molded aperture 206 is deflected by the deflectors 208 and 209 after the irradiation alignment is performed by the objective lens 207. The electron beam 200 is corrected in the irradiation position by the deflector 208, and then the mask 216 placed in the drawing chamber 103 is irradiated.

A stage 105 is arranged inside the drawing chamber 103. The stage 105 is driven in the X direction, the Y direction, and the Z direction by the control calculation unit 160. The mask 216 to be processed is placed on the stage 105. The mask 216 may be, for example, one in which a light-shielding film such as a chromium (Cr) film is formed on a mask substrate, and a resist film is further formed on the light-shielding film. A predetermined pattern is drawn on the resist film by the electron beam 200. The mask 216 may be, for example, mask blanks on which no pattern has been formed yet.

The control calculation unit 160 includes a drawing data storage unit 110a for storing drawing data, a shot data generation unit 110b for processing drawing data to generate shot data, and a drawing control unit 110c for controlling the electronic lens barrel 102. ing. The drawing data storage unit 110a is a storage unit that stores drawing data for drawing a pattern on the mask 216. The shot data generation unit 110b divides the drawing pattern defined by the drawing data and generates shot data. The drawing control unit 110c controls the drawing pattern drawing described above based on the generated shot data while moving the stage 105 in the longitudinal direction of the stripe region.

FIG. 2 is a schematic view showing an example of the configuration of the electron gun 201 according to the first embodiment. The electron gun 201 includes a chamber 217, a receptacle 22, a contact 222, a cathode 14, an anode 23, a barrel 13, and a rotation mechanism 12. As shown in FIG. 2, the electron gun 201 is a turret type electron gun in which a plurality of cathodes 14 are arranged on a barrel 13 and made rotatable by a rotation mechanism 12.

The electron gun chamber (hereinafter, also referred to as a chamber) 217 accommodates components of the electron gun 201 such as a barrel 13 and a plurality of cathodes 14. The inside of the electron gun chamber 217 is in a decompressed state.

The receptacle 22 is made of an insulating material and is configured to receive the connector 20 of the cable 10. By inserting the cable 10 into the receptacle 22, the connection surface F20 at the tip of the connector 20 and the bottom surface F22 of the receptacle 22 face each other and approach each other, and the power line 30 of the cable 10 is electrically connected to the contact 222 provided on the receptacle 22. Connected to. As a result, the electric power from the power supply line 30 is supplied to the cathode 14 via the contact 222. Further, one of the optical fiber wires 40 of the cable 10 is exposed on the connection surface F20 of the connector 20, and the other optical fiber wire 40 is a cathode from the receptacle 22 so that the discharge light emission generated in the electron gun 201 can be captured. It is exposed to the 14 side. The point of making it possible to capture the discharge light emission generated in the power supply line 30 or the electron gun 201 will be described in detail later with reference to the drawings of FIGS. 3 and later. As a result, the optical fiber wire 40 can transmit the discharge light emitted from the power supply line 30 near the connection surface F20 at the end of the connector 20 or the discharge light emitted from the electron gun 201. The configuration of the cable 10 will be described in more detail later.

The contact 222 is provided at the tip of the receptacle 22 inside the chamber 217 and is electrically connected to the cathode 14 to supply power. The cathode 14 emits an electron beam when powered.

The barrel 13 is a cylindrical rotating body (turret) that holds a plurality of cathodes 14 on its sides. The barrel 13 is connected to the rotation mechanism 12 and can rotate around the central axis B of the barrel 13 as a rotation axis. Of the plurality of cathodes 14, one cathode 14 is used to emit an electron beam. When the cathode 14 used deteriorates, the user rotates the barrel 13 to replace the cathode 14. By providing the barrel 13 with the plurality of cathodes 14 in this way, the cathodes 14 can be replaced without releasing the reduced pressure state.

The anode 23 is provided so as to face the cathode 14, and emits an electron beam emitted from the cathode 14 through the opening 24. A voltage of, for example, −50 kV is applied to the cathode 14 and the barrel 13 from a wiring (not shown). On the other hand, the anode 23 is grounded. As a result, an electric field is generated between the cathode 14 and the anode 23, and the electrons emitted from the cathode 14 are accelerated and emitted through the opening 24 of the anode 23.

3A and 3B are schematic cross-sectional views showing a configuration example of a cable 10, an electron gun 201, and a high voltage power source (HVPS). FIG. 3B is a schematic cross-sectional view showing the configuration of the connector 20 inserted into the receptacle 22 of the electron gun 201 and its surroundings. The electron gun 201 is shown by a broken line.

The cable 10 includes a connector 20, a power supply line 30, optical fiber lines 40a and 40b, an insulator 50, and a connector 60.

The connector 20 as the first connector is provided at one end of the cable 10 and is fitted in the receptacle 22 of the electron gun 201. The connector 20 introduces one end of the power supply line 30 into the electron gun 201 as a load. As a result, the power supply line 30 is electrically connected to the cathode 14 of the electron gun 201 as a load. The connector 20 is made of an insulator such as resin or ceramic in order to prevent the power supply line 30 from being short-circuited to another configuration of the electron gun 201.

The power supply line 30 electrically connects the high-voltage power supply HVPS and the electron gun 201, and applies a high voltage (for example, ± 50 kV) from the high-voltage power supply HVPS to the cathode 14 of the electron gun 201. When the power supply line 30 supplies electric power to the cathode 14, an electron beam is emitted from the cathode 14. One end of the power supply line 30 is drawn out from the connection surface F20 of the connector 20 and is electrically connected to the cathode 14 via the contact 222 of the electron gun 201. The other end of the power supply line 30 is pulled out from the connector 60 and connected to the power supply 70 of the high-voltage power supply HVPS. As a result, the power supply line 30 can supply electric power from the high-voltage power supply HVPS to the cathode 14 of the electron gun 201. For the power supply line 30, for example, a low resistance metal such as copper or tungsten is used.

The optical fiber line 40a is provided along (parallel to) the power supply line 30, and transmits the discharge light emitted at or near one end E30 of the power supply line 30 to the high-voltage power supply HVPS.

One end of the optical fiber line 40a is substantially parallel to the connection surface F20 between the power supply line 30 and the cathode 14 in the connector 20, and is substantially flush with each other. As a result, the optical fiber line 40a can be regarded as discharge light emission at one end E30 of the power supply line 30 or its vicinity. The other end of the optical fiber wire 40a is drawn out from the connector 60 and connected to a photomultiplier tube (PMT) that detects discharge light emission via a high-voltage power supply HVPS. As a result, the optical fiber line 40a can transmit the discharge light emission at one end E30 of the power supply line 30 or its vicinity to the photomultiplier tube PMT. The detector may be a photomultiplier tube PMT, a photodiode, an avalanche photodiode, a silicon photomultiplier, a microchannel plate, or the like.

The optical fiber line 40b is provided along the power supply line 30 (in parallel), and transmits the discharge light emission on the electron gun 201 side to the high voltage power supply HVPS. One end of the optical fiber wire 40b is terminated inside the electron gun 201 from the connection surface F20 through the optical fiber connector. The optical fiber connector allows the cable 10 to be attached and detached while maintaining the reduced pressure state in the electron gun 201.

As a result, the optical fiber wire 40b can capture the discharge light emitted by the electron gun 201. The discharge emission generated by the electron gun 201 is, for example, discharge emission between the cathode 14, contact 222 or barrel 13 and the anode 23, or discharge between the cathode 14, contact 222 or barrel 13 and the housing of the chamber 217. Light emission and the like are included. The optical fiber wire 40b can capture such discharge light emission on the electron gun 201 side. The other end of the optical fiber wire 40b transmits discharge light emission to the photomultiplier tube PMT via the high-voltage power supply HVPS.
As a result, the optical fiber wire 40b can transmit the discharge light emitted from the electron gun 201 to the photomultiplier tube PMT.

On the other hand, the optical fiber line 40b cannot capture the discharge light emission generated at or near one end E30 of the power supply line 30. Therefore, the optical fiber line 40a is provided on the connection surface F20 in order to capture the discharge light emission generated at one end E30 of the power supply line 30 or its vicinity. By providing both the optical fiber lines 40a and 40b, the photomultiplier tube PMT can detect both the discharge light emission of one end E30 of the power supply line 30 or its vicinity and the discharge light emission of the electron gun 201.

The connector 60 as the second connector is provided at the other end of the power supply line 30 and is fitted in the receptacle 62 of the high-voltage power supply HVPS. The connector 60 introduces the other end of the power supply line 30 into the high-voltage power supply HVPS. As a result, the power supply line 30 is electrically connected to the power supply 70 of the high-voltage power supply HVPS, and power can be supplied to the electron gun 201. The connector 60 is made of an insulator such as resin or ceramic in order to prevent the power supply line 30 from being short-circuited to another configuration of the high-voltage power supply HVPS.

The insulator 50 is provided so as to cover the power supply line 30 and the optical fiber lines 40a and 40b. For the insulator 50, for example, a high withstand voltage insulating material such as resin is used.

The high-voltage power supply HVPS includes a power supply 70 and an optical path 80. The power supply 70 is configured so that a high voltage (for example, ± 50 kV) can be applied to the power supply line 30 via the receptacle 62. A high-voltage transparent material is used for the optical path 80, and the light from the optical fiber lines 40a and 40b can be transmitted (relayed) to the photomultiplier tube PMT without being significantly deteriorated. For the optical path 80, for example, a highly pressure-resistant transparent liquid such as silicone oil or fluorinert may be used. Further, the optical path 80 may be an extension of the optical fiber connected to the optical fiber lines 40a and 40b. In this case, the extension of the optical fiber transmits the light from the optical fiber lines 40a and 40b to the photomultiplier tube PMT.

The photomultiplier tube PMT generates an electric signal by receiving discharge light emission from the optical fiber wires 40a and 40b and performing photoelectric conversion. As a result, the photomultiplier tube PMT can receive the light from the high-voltage power supply HVPS and detect the discharge light emission in the electron gun 201 or the power supply line 30. By attaching a photomultiplier tube PMT to each of the optical fiber wires 40a and 40b, discharge light emission is detected separately. Thereby, the photomultiplier tube PMT can identify whether the detected discharge light emission is the discharge light emission generated in the electron gun 201 or the power supply line 30.

The oscilloscope OSC receives an electrical signal from the photomultiplier tube PMT and displays the change in this electrical signal. The oscilloscope OSC distinguishes and displays the discharge light emission of each of the optical fiber lines 40a and 40b. As a result, the user can know that the discharge light emission has occurred and the approximate position of the discharge light emission by referring to the oscilloscope OSC. As described above, the oscilloscope OSC is provided as a user interface so that the user can recognize the discharge light emission.

Although the detailed configuration of the connector 60 is not shown, it may be the same as the configuration of the connector 20 of FIG. 3 (B). Alternatively, the configuration of the connector 60 may be different from the configuration of the connector 20. By making the connectors 20 and 60 both have the same configuration, the connectors 20 and 60 can be manufactured without distinction and can be inserted into any of the receptacles 22 and 62.

FIG. 4 is a schematic cross-sectional view showing a configuration example of the cable 10. FIG. 4 shows a cross-sectional view of the cable 10 cut in a direction substantially perpendicular to the extending direction (direction perpendicular to the paper surface of FIG. 4).

Optical fiber wires 40a and 40b are provided at the center of the cable 10. Three power supply lines 30a, 30b, 30c are wound around the optical fiber lines 40a, 40b with the optical fiber lines 40a, 40b as substantially the center. For example, the power supply lines 30a, 30b, and 30c rotate in the direction of arrow A (or vice versa) around the optical fiber lines 40a and 40b with the optical fiber lines 40a and 40b as substantially the center as the cable 10 extends in the extending direction. It is wound in a spiral so that it does. That is, although not shown, the power supply lines 30a, 30b, and 30c are spirally wound around the substantially center of the cable 10. As a result, the power supply lines 30a, 30b, and 30c make the potential gradient inside the cable 10 substantially equal to the center of the cable 10. For example, when the shield layer 90 is grounded, a large electric field is applied between the power supply lines 30a to 30c and the shield layer 90. Even in such a case, since the power supply lines 30a, 30b, and 30c are arranged substantially evenly with respect to the center of the cable 10, the potential gradient is made substantially symmetrical with respect to the center of the cable 10. Therefore, the power supply lines 30a to 30c can pass the optical fiber lines 40a and 40b into the cable 10 without significantly biasing the potential gradient inside the cable 10. Although the power supply lines 30a to 30c have high voltages, they do not significantly affect the potential gradient because they transmit voltages close to each other.

The insulator 50 covers the periphery of the optical fiber lines 40a and 40b and the power supply lines 30a, 30b and 30c. Further, another insulator 45 is provided between the insulator 50 and the optical fiber wires 40a and 40b or the power supply lines 30a, 30b and 30c. The insulator 50 is a high withstand voltage insulator and is, for example, a high resistance material of several to several tens of teraohm (TΩ).

The shield layer 90 covers the insulator 50. For example, a conductive metal is used for the shield layer 90 and is grounded. The shield layer 90 functions as a shield for protecting the power supply lines 30a to 30c from the influence of electromagnetic waves from the outside, in addition to suppressing the electric shock from the power supply lines 30a to 30c and reducing the influence of the potential gradient from the surroundings.

Further, the protective film 95 covers the shield layer 90. For example, an insulating material is used for the protective film 95. The protective film 95 is provided to electrically insulate the shield layer 90 from the outside of the cable 10.

By using the cable 10 having the above configuration, the optical fiber wire 40a detects the discharge light emission from the power supply line 30 in the vicinity of the connection surface F20 at the end of the connector 20 with the photomultiplier tube PMT through the high voltage power supply HVPS. can do. Further, the optical fiber wire 40b can detect the discharge light emission at the contact 222 or the cathode 14 of the electron gun 201 with the photomultiplier tube PMT through the high voltage power supply HVPS. As a result, the user can identify the position where the discharge light emission is generated and determine the maintenance policy. If the discharge is occurring in the power supply line 30, it is sufficient to replace the cable 10. Therefore, the downtime of the charged particle beam device 100 can be short. When the discharge is generated by the electron gun 201, it is necessary to release the depressurized state of the charged particle beam device 100 to maintain the electron gun 201. In this case, the downtime of the charged particle beam device 100 becomes long. However, since it is not necessary to release the depressurized state of the charged particle beam device 100 until the discharge is generated in the power supply line 30, the down time of the charged particle beam device 100 can be shortened as a whole.

Further, in the present embodiment, the optical fiber lines 40a and 40b are wired together with the power supply line 30 in the cable 10. If the optical fiber wires 40a and 40b are to be introduced into the electron gun 201 separately from the power supply line 30, an insulator (shown) is used to pass the optical fiber wires 40a and 40b inside the barrel 13 of the electron gun 201. It is necessary to arrange a lot of. On the contrary, such an insulator may cause an electric discharge. On the other hand, in the present embodiment, since the optical fiber lines 40a and 40b are wired together with the power supply line 30 in the cable 10, it is not necessary to arrange an extra insulator in the barrel 13. This can reduce the discharge in the electron gun 201.

In the above embodiment, two optical fiber wires 40a and 40b are provided in the cable 10. However, either one of the optical fiber wires 40a and 40b may be provided in the cable 10. Further, the number of optical fiber lines in the cable 10 may be 3 or more.

(Second Embodiment)
FIG. 5 is a schematic cross-sectional view showing a configuration example of the discharge detection system according to the second embodiment. In the second embodiment, the connector 60 and the receptacle 62 are omitted, and the cable 10 is integrally connected to the high voltage power supply HVPS. Therefore, the cable 10, the high-voltage power supply HVPS, and the photomultiplier tube PMT are configured as an integrated discharge detection system 300. Other configurations of the second embodiment may be the same as the corresponding configurations of the first embodiment. Therefore, the same effect as that of the first embodiment can be obtained in the second embodiment.

Further, since the discharge detection system 300 does not require the connector 60 and the receptacle 62, the number of parts can be reduced.

The oscilloscope OSC is usually removable from the photomultiplier tube PMT, but may be integrated with the discharge detection system 300.

(Third Embodiment)
FIG. 6 is a schematic cross-sectional view showing a configuration example of the charged particle beam device according to the third embodiment. In the third embodiment, the connector 20 and the receptacle 22 are further omitted, and the cable 10 is integrally connected to the electron gun 201. Therefore, the cable 10, the high-voltage power supply HVPS, and the photomultiplier tube PMT are integrally configured with the charged particle beam device 100. Other configurations of the third embodiment may be the same as the corresponding configurations of the second embodiment. Therefore, the third embodiment can obtain the same effect as the second embodiment. One end of the optical fiber line 40b may be arranged at an arbitrary position of the power supply line 30 in order to detect the discharge light emission at the arbitrary position of the power supply line 30.

Further, since the charged particle beam device 100 according to the third embodiment does not require the connector 20 and the receptacle 22, the number of parts can be further reduced.

The oscilloscope OSC is usually removable from the photomultiplier tube PMT, but may be integrated with the charged particle beam device 100.

Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, as well as in the scope of the invention described in the claims and the equivalent scope thereof.

100 electron beam drawing device, 150 drawing unit, 160 control calculation unit, 217 electron gun chamber, 201 electron gun, 217 chamber, 222 contacts, 14 cathodes, 23 anodes, 13 barrels, 12 rotation mechanism, 10 cables, 30a to 30c power supply. Wire, 40a, 40b optical fiber wire, 50 insulator, 20,60 connector, 22,62 receptacle, 90 shield layer, 95 protective film

Claims (7)

A charged particle gun that emits a charged particle beam,
A power supply line that supplies electric power from the voltage source to the charged particle gun, and a first optical fiber line that is provided along the power supply line and transmits discharge light emission from the charged particle gun or the power supply line to the voltage source side. , A cable with an insulator covering the power line and the first optical fiber line,
A voltage source that is connected to the cable, allows light from the first optical fiber line to pass through, and supplies a voltage to the power supply line, and
A charged particle beam device including a detector that receives light from the voltage source and detects discharge light emission in the charged particle gun or the power supply line. A power supply line that supplies power from a voltage source to a load, a first optical fiber line that is provided along the power supply line and transmits discharge light emission from the load or the power supply line to the voltage source side, the power supply line, and the power supply line. A cable with an insulator covering the first optical fiber wire,
A voltage source that is connected to the cable, allows light from the first optical fiber line to pass through, and supplies a voltage to the power supply line, and
A discharge detection system including a detector that receives light from the voltage source and detects discharge light emission in the load. The discharge detection system according to claim 2, wherein the voltage source has a high withstand voltage transparent body that allows light from the first optical fiber line to pass through. The power supply line is wound around the first optical fiber line with the first optical fiber line as a substantially center.
The discharge detection system according to claim 2, wherein the insulator is provided around the first optical fiber line and the power supply line. A first connector provided at one end of the power supply line and connecting one end of the power supply line to the load is further provided.
The second aspect of the present invention, wherein one end of the first optical fiber wire is substantially parallel to the connection surface between the power supply line and the load in the first connector, or is exposed to the load side. Discharge detection system. A second optical fiber line provided along the power supply line and transmitting light emission from the load or discharge light in the power supply line to the voltage source side.
A first connector provided at one end of the power supply line and connecting one end of the power supply line to the load is further provided.
One end of the first optical fiber wire is substantially parallel to the connection surface between the power supply line and the load in the first connector.
The discharge detection system according to claim 2, wherein one end of the second optical fiber wire is exposed to the load side. The cable according to any one of claims 2 to 6, wherein the cable is provided at the other end of the power supply line and further includes a second connector for connecting the other end of the power supply line to the voltage source. Discharge detection system.

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