JPH076265U - Electrode structure of plasma CVD anode - Google Patents

Abstract

(57) [Summary] [Object] To provide an anode in which discharge is not hindered in a plasma CVD apparatus. A shield plate portion 22e, which is held at the same potential as the vacuum chamber and has a hole portion 24 formed in a portion through which a plasma beam passes, is arranged outside the anode plate 26. The shield gas supplied to the introduction path 35 flows out from the hole into the vacuum chamber, and a pressure gradient is generated between the anode surface and the vacuum chamber. Plasma generated by the shield gas is generated near the hole. This prevents the deposition of film-forming components on the anode surface and prevents the discharge from being hindered.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a plasma CVD apparatus, and more particularly to an electrode structure of its anode.

[0002]

[Prior art]

 First, the plasma CVD apparatus will be outlined with reference to FIG.

The illustrated plasma CVD apparatus uses a so-called pressure gradient type plasma source, and in the vacuum chamber (processing tank) 11, an object to be processed 12 is arranged and an anode part 13 is arranged as shown in the drawing. It The vacuum chamber 11 is evacuated and the source gas is introduced. A discharge plasma flow is generated between the cathode part 14 and the anode part 13 to form a film (insulating film) on the object to be processed 12.

Here, the structure of the anode portion 13 will be outlined with reference to FIG.

The anode part 13 includes an anode block 13a, and this anode block 13a is attached to a mounting flange 13b. The mounting flange 13b is mounted on the inner wall of the vacuum chamber by the insulating block 13c.

A permanent magnet 13d is arranged in a hollow space formed by the anode block 13a and the mounting flange 13b, and cooling water is injected into this hollow space by a water conduit 13e.

[0007]

[Problems to be solved by the device]

 By the way, in the above-mentioned plasma CVD apparatus, there is a problem that an insulating film is formed on the surface of the anode part because the anode part is arranged inside the processing tank, and as a result, the discharge is hindered. Then, in order to reduce such a problem, it is necessary to form only a conductive film or an insulating film that easily evaporates.

An object of the present invention is to provide an anode for plasma CVD that does not disturb discharge.

[0009]

[Means for Solving the Problems]

 According to the present invention, an anode part is provided in the vacuum chamber, which is used in a plasma CVD apparatus having a vacuum chamber for forming a film on an object to be processed by using a plasma beam generated by a DC arc discharge, and the anode part. And a magnet means for generating a magnetic field for guiding the plasma beam, and a portion which is placed at a position that shields the outside of the anode part and is held at the same potential as the vacuum chamber and through which the plasma beam passes. An electrode structure for a plasma CVD anode is obtained, which has a shield electrode portion having a hole formed therein and a shield gas outflow means for causing a shield gas to flow out into the vacuum chamber from the hole.

[0010]

[Action]

 In the present invention, a shield electrode portion is provided at a position that shields the anode portion, and a shield gas such as argon gas is allowed to flow out through a hole formed in the shield electrode portion. There will be a pressure gradient across. Further, plasma is generated by the shield gas near the shield electrode part. Therefore, the cations and radical particles of the film forming molecules cannot reach the positive electrode surface due to the flow of the shielding gas and the electric field, and as a result, the deposition of the film forming molecules on the anode surface can be suppressed.

[0011]

【Example】

 The present invention will be described below with reference to examples.

With reference to FIG. 1, an opening 21 is formed in the wall of the vacuum chamber, and a cylindrical shield flange 22 is inserted into this opening 21. The shield flange 22 is fixed to the vacuum chamber wall by bolts 22b via the O-ring 22a. As shown in the figure, the shield flange 22 is formed with a hollow portion 22c extending in the axial direction (longitudinal direction), and a ring-shaped electromagnetic coil 23 is arranged at a predetermined position of the hollow portion 22c. There is. Further, a cooling water introduction port 22d is formed in the shield flange 22, and the cooling water introduction port 22d communicates with the hollow portion 22c.

A shield plate portion 22e extending toward the center is provided at the upper end of the shield flange 22, and a hole portion 24 is formed in the center portion (a portion through which the plasma beam passes) of the shield plate portion 22e. There is. A heat resistant sleeve 25 is attached to the hole 24 of the shield plate 22e. An anode plate 26, which will be described later, is arranged inside the shield plate portion 22e so as to be shielded by the shield plate portion 22e.

The anode according to the present invention comprises a flat anode plate (made of copper) 26, and this anode plate 26 is attached to an anode block 27 via an O-ring 26a to connect the anode plate 26 and the anode block 27. The hollow portion 28 is formed by. A permanent magnet 29 is attached to the lower surface of the anode plate 26 in the hollow portion 28. The cooling water introducing pipes 30 and 31 are inserted in the hollow portion 28. An insulating block 32 is arranged at the lower end of the anode block 27 via an O-ring 27a, and a mounting flange 33 is arranged at the lower end of the insulating block 32 via an O-ring 32a. Then, the insulating block 32 and the mounting flange 33 are fixed to the positive electrode block 27 by the bolts 33a to form the anode main body portion 34.

As shown, the anode main body 34 is inserted into the shield flange 22, and the shield flange 22 is fixed to the mounting flange 33 by the bolt 34b via the O-ring 34a. At this time, a space (introduction passage) 35 is formed between the shield flange 22 and the anode main body 34 as shown in the drawing, and a shield gas introduction pipe 36 is connected to the introduction passage 35. Further, when the anode main body 34 is inserted into the shield flange 22, the permanent magnet 29 is in a position surrounded by the electromagnetic coil 23.

Here, also referring to FIG. 3, an operation when the above-described anode is used in a plasma CVD apparatus will be described. First, the cooling water is introduced from the cooling water inlet 22d into the hollow portion 22c, and the cooling water circulates in the hollow portion 28 via the cooling water pipes 30 and 31. Further, the electromagnetic coil 23 is energized, and a shield gas such as argon gas is supplied to the introduction path 35 from the shield gas introduction pipe 36. The shield flange 22 is kept at the same potential as the vacuum chamber.

The plasma beam is guided near the anode along the lines of magnetic force formed by the electromagnetic coil 23. At this time, the plasma beam reaches the central portion of the anode plate 26 through the hole 24 due to the lines of magnetic force generated by the permanent magnet 29. That is, the plasma beam is focused by the permanent magnet 29.

On the other hand, the shield gas supplied to the introduction path 35 flows out from the hole 24 into the vacuum chamber. This results in a pressure gradient between the anode surface and the vacuum chamber. Further, plasma (hereinafter referred to as shield plasma) due to shield gas is generated near the hole 24.

The cations and radical particles of the film-forming molecules generated by the plasma beam must fly against the flow of the shield gas and the electric field near the hole 24 when reaching the anode surface. Therefore, by using the anode having the above-mentioned structure, it is possible to prevent the deposition of film-forming components on the anode surface as much as possible.

By the way, anions such as oxygen flow into the surface of the anode along with the electrolysis, and as a result, the surface of the anode is easily oxidized. Therefore, it is desirable to coat the anode surface with platinum.

Next, another embodiment according to the present invention will be described with reference to FIG.

As shown in FIG. 2A, a trapezoidal anode plate 41 is fixedly supported by an insulator portion 42 via an O-ring 41 a. An iron core 44 is arranged on the lower flange 43, and a plurality of permanent magnets 45 are arranged on the iron core 44 at predetermined intervals. An iron core 46 is arranged on the permanent magnet 45 so as to connect the permanent magnets.

The above-mentioned lower flange 43 is fixed to the insulator portion 42 via the O-ring 42 a, whereby the insulator portion 42 is supported by the lower flange 43. A closed space 47 is formed by the anode plate 41, the insulator portion 42, and the lower flange 43, and the permanent magnet 45 is arranged in the closed space 47.

Holes 43a and 43b are formed in the lower flange 43, and cooling water pipes 48 and 49 are connected to the holes 43a and 43b, respectively. As a result, cooling water circulates in the enclosed space.

A shield plate 50 is arranged on the upper side of the anode plate 41 (this shield plate 50 is kept at the same potential as the vacuum chamber), and this shield plate 50 is supported by the lower flange 43 by the support portion 51. .

As shown in FIG. 2B, the shield plate 50 is provided with slits 52 extending in the arrangement direction of the permanent magnets 45.

With reference to FIG. 2C, a shield gas introduction pipe 53 is arranged on the side of the anode plate 41, and the shield gas introduction pipe 53 is supported by the support portion 51 by a support member 54. A space is formed by the anode plate 41, the shield plate 50, and the support member 51, and the shield gas supplied from the shield gas introduction pipe 53 to this space is guided to the slit 52 without leaking to the other. 2B, a cooling water pipe 55 is laid on the lower surface of the shield plate 50, and the cooling water circulates in the cooling water pipe 55.

In this embodiment, the plasma beam passes through the slit 52 and reaches the anode plate 41 by the lines of magnetic force of the permanent magnet. Similar to the embodiment shown in FIG. 1, the shield gas starts flowing from the slit 52 into the vacuum chamber, which causes a pressure gradient between the anode surface and the vacuum chamber. In addition, plasma generated by the shield gas is generated near the slit 52. Therefore, as in the case of the anode in FIG. 1, cations and radical particles of film forming molecules cannot reach the anode surface due to the flow of the shielding gas and the electric field, and as a result, the deposition of film forming molecules on the anode surface is suppressed. can do. It is desirable to coat the surface of the anode plate with platinum to prevent oxidation.

[0029]

[Effect of device]

 As described above, according to the present invention, it is possible to suppress the deposition of film forming molecules on the surface of the anode, and as a result, it is possible to stably form a film without inhibiting discharge.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a plasma CVD anode according to the present invention.

2A and 2B are views showing another embodiment of the plasma CVD anode according to the present invention, wherein FIG. 2A is a front sectional view, FIG. 2B is a plan view, and FIG. 2C is a side sectional view.

FIG. 3 is a diagram schematically showing a plasma CVD apparatus.

FIG. 4 is a cross-sectional view showing a conventional plasma CVD anode.

[Explanation of symbols]

 11 Vacuum Chamber (Treatment Tank) 12 Workpiece 13 Anode 14 Cathode 21 Opening 22 Shield Flange 23 Electromagnetic Coil 24 Hole 24 25 Heat Resistant Sleeve 26, 41 Anode Plate 27 Anode Block 28 Hollow 29, 45 Permanent Magnet 30 , 31 Cooling water pipe 32 Insulating block 33 Mounting flange 34 Anode body part 35 Space (introduction path) 36, 53 Shield gas introducing pipe 42 Insulator part 43 Lower flange 44, 46 Iron core 47 Sealed space 48, 49, 55 Cooling water pipe 50 Shield Plate 51 support part 52 slit 54 support member

Claims (2)

[Scope of utility model registration request] 1. An anode part, which is used in a plasma CVD apparatus provided with a vacuum chamber for forming a film on an object to be processed by using a plasma beam by a DC arc discharge, and an anode part located in the vacuum chamber, A magnet means for generating a magnetic field for guiding the plasma beam, and a hole portion is formed at a position that shields the outside of the anode portion and is held at the same potential as the vacuum chamber and through which the plasma beam passes. And a shield gas outflow means for outflowing the shield gas into the vacuum chamber from the hole, the electrode structure of the plasma CVD anode. 2. The plasma CVD anode electrode structure according to claim 1, wherein the surface of the anode portion is coated with platinum.
Structure of the anode for automobile.