JPH02121300A - Arc torch - Google Patents

Abstract

PURPOSE:To enable the title torch to stably generate high-density arc plasma even through low-current arc discharge by having a counter electrode space from a torch electrode, one-side magnetic pole arranged in an arc torch body and a counter magnetic pole arranged opposite to this one-side magnetic pole on the side of the counter electrode. CONSTITUTION:A torch electrode 1 is connected at the hollow portion to an arc plasma source gas passage 5a by an arc torch body 2 and a coaxial cylinder-shaped gas pipe 5. A magnetic pole 9 is arranged in the arc torch body 2, while another counter electrode 12 is arranged on the side of a counter electrode 11, and then locally concentrated magnetic flux generated between the torch electrode 1 and the target of the counter electrode 11 by these magnetic poles 9, 12 on both sides causes anisotropy to the movement of arc plasma, so that arc discharge is limited between the torch electrode 1 and the target. Thus, operational stability of the title torch to outside disturbance is increased, with high-density arc plasma also kept under a high vacuum for enabling the torch to have high current density.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The arc torch of the present invention is used in plasma chemical reactors and thin film production devices in the field of plasma chemistry, which has recently been developed in academic research and industry. be.

It can also be used for welding in vacuum under reduced pressure.

[Prior Art] When conventional arc torches are used for welding, most of them are used in the atmosphere, and are rarely used in a reduced pressure vacuum atmosphere.

Moreover, as a plasma generation means, it generates higher density plasma than other methods.

[Problems to be Solved by the Invention] When a conventional arc torch is used under reduced pressure, arc discharge does not necessarily occur only between the target of the torch electrode and the counter electrode, but also at locations that can become the electrodes of the reduced pressure container. A discharge arc may also occur, and it is not easy to maintain stable arc discharge. Further, when the discharge current value is made small, the arc plasma becomes unstable due to disturbances, and similarly, it becomes difficult to maintain the discharge. In addition, under high vacuum, the density of arc plasma becomes low and the current becomes low, making it difficult to maintain discharge.

[Means and effects for solving the problem] In order to solve the above-mentioned problems, the present invention arranges a magnetic pole inside the arc torch main body, and arranges another opposing magnetic pole on the opposing electrode side. The locally concentrated magnetic flux generated between the target of the torch electrode and the counter electrode causes anisotropy in the movement of the arc plasma, which confines the arc discharge between the torch electrode and the target, increasing the stability against disturbances and increasing the It maintains high-density arc plasma under vacuum and obtains high current density.

In addition, the shape of the torch electric i of the arc torch is made hollow,
Supplying the arc plasma source gas through this hollow passageway makes the arc plasma column even thinner, compensates for the density loss of the high-density arc plasma, and maintains the high-density arc plasma and high vacuum inside the vessel for a long time. be.

Further, by providing a cooling medium passage inside the arc torch main body, the cooling medium is prevented from being consumed and demagnetized due to exposure to high temperatures of the torch electrode and magnetic pole.

Furthermore, the yoke at the other end of the arc torch deforms the shape of the magnetic flux to prevent arc discharge to a container other than the target.

[Embodiment] An embodiment of the present invention will be described in detail below with reference to FIGS. 1 and 2.

That is, the hollow rod torch electrode 1 is attached to one end of the arc torch main body 2 via an O-ring seal 3, and screwed into the J with several screws 4.
It is marked R. The hollow part of the torch electrode above is the main body 2.
An arc plasma source gas passage 5a1:Kn is established by a gas vibrator 5 having a coaxial cylindrical shape. Also, torch electrode 1
comes into contact with the coolant flowing through the coolant passage 7 at the upper ring portion 6 . The coolant passage 7 partitions a gap between the gas vibrator 5 and the main body 2 with a coaxial cylindrical vibrator 8 to form a coolant circulation passage. A coaxial cylindrical magnetic pole 9 is arranged around the outer periphery of the vibrator 8, and a yoke 10 is arranged above the magnetic pole 9. On the other hand, a target of a counter electrode 11 electrically connected to a vacuum container 18 is located across a space from the torch electrode 1, and a counter magnetic pole 12 is placed in the container 18 by a holder 13, further separated by a space. Arc plasma source gas passage 5
a and the coolant passage 7 are connected to a gas connector 15 and a coolant connector 16 via a bracket 14, respectively. Further, a torch electrode terminal 17 attached to the other end of the arc torch main body 2 is electrically connected to the arc torch main body 2, and the torch electrode 1 is electrically connected to the main body 2.

The coolant connector 16 is connected to a coolant circulation pump 19 . Further, the torch γ is connected to the pole terminal 17 and the vacuum vessel 18.
is connected to the arc torch power supply 20. Furthermore, vacuum container 1
8 is connected to a vacuum pump 21.

Next, the operation of the above embodiment will be explained. Torch electrode terminal 17
is connected to the cathode of the arc torch power source 20, while the anode is connected to the vacuum vessel 18. Therefore, when arc plasma source gas is supplied through the gas connector 15, arc plasma source gas passage 5a1, and the hollow part of the torch electrode 1 in the high vacuum vessel 18, an arc discharge occurs between the torch RU pole 1 and the counter electrode 11. Furthermore, even if the container 18 is initially filled with arc plasma source gas at a low pressure, arc discharge will occur. The arc plasma generated by the discharge is easily moved only in the direction of the central axis of the arc torch body 2, but difficult to move in the vertical direction, due to the locally concentrated magnetic flux generated by the bimagnetic poles formed by the magnetic pole 9 and the opposing magnetic pole 12. Therefore, the arc plasma is stably maintained at high density near the central axis of the arc torch body 2. In addition, the magnetic flux generated at the other end of the arc torch main body 2 easily enters the yoke 10.
Since the magnetic flux changes to become parallel to the central axis of the arc torch body 2, the magnetic flux crosses the line segments connecting each part of the arc torch body 2 and the vacuum vessel 18, causing a discharge between the arc torch body 2 and the vacuum vessel 18. suppress. The degree of vacuum within the vacuum vessel 18 can be further increased while maintaining the above arc discharge state.

[Effects of the Invention] The present invention makes it possible to limit arc discharge only between the torch electrode and the target under reduced pressure and high vacuum,
It has highly controllable and high-performance functions that can stably generate high-density arc plasma even with low current arc discharge, and introducing the plasma source gas through a hollow rod-shaped torch electrode can further enhance the above functions. possible, for a long time,
Since the high-density arc plasma action can be maintained in a narrow and localized manner, the arc torch can be used over a wide range of areas. Furthermore, the cooling medium in the cooling medium passage has an economical effect in that the life of the conker can be significantly improved. Therefore, when used in a plasma chemical reactor and a thin film production apparatus, it has the great effect of being able to control the reaction opening and the amount of sputtering over a wide range and with high efficiency.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway side view showing one embodiment of the present invention, and FIG.
The figure is a configuration explanatory diagram showing an example of a state in which the present invention is connected to an accessory device. 1... Torch electrode, 5... Gas pipe, 5a...
Arc plasma source gas passage, 7... Coolant passage, 9.
...Magnetic pole, 10...Yoke, 11...Counter electrode, 1
2...Opposing magnetic poles.

Claims (4)

[Claims] (1) In an arc torch that generates arc plasma, a magnetic flux exists between an electrode provided at one end of the arc torch main body, a counter electrode provided with a space between the torch electrode and the torch electrode, and the counter electrode and the torch electrode. An arc torch characterized by comprising: one magnetic pole disposed inside the arc torch main body so as to generate a . (2) The arc torch according to claim 1, wherein the torch electrode is formed into a hollow rod shape for introducing the arc plasma source gas. (3) The arc torch according to claim 1 or 2, characterized in that a cooling medium passage is provided inside the arc torch body in order to cool the torch electrode and one of the magnetic poles inside the arc torch body. (4) The arc according to claim 1, characterized in that a yoke is provided inside the arc torch main body to spatially restrict the magnetic flux generated on the other end side of the arc torch main body of one magnetic pole inside the arc torch main body. torch.