JPH0216381B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a discharge electrode, and particularly to a discharge electrode for generating magnetron discharge and hollow cathode discharge.

[Technical background of the invention and its problems]

Conventionally, there are various types of discharge electrodes used in sputtering and the like to scatter electrode members such as targets onto the workpiece, but usually a magnetron method is often used, which has a closed magnetic field on the target surface. . Such a discharge electrode is usually used as a cathode, and a high electric field is applied between the cathode and the anode to cause a plasma discharge within a closed magnetic field above the target surface, and the target material is bombarded with generated ions. A film is formed on the object to be processed.

However, in the above-mentioned magnetron type discharge electrode, the condition is that a parallel magnetic field exists on the target surface, but as the target material,
When using a ferromagnetic material such as iron, most of the lines of magnetic force that should create a parallel and closed magnetic field pass through the target, making it difficult to obtain a parallel magnetic field on the target surface. It was hot.

[Purpose of the invention]

The present invention has been made in view of the above points, and
It is an object of the present invention to provide a discharge electrode capable of generating a stable plasma discharge and forming a uniform film regardless of whether the target is a ferromagnetic material or a non-magnetic material.

[Summary of the invention]

In order to achieve the above object, the discharge electrode according to the present invention includes:
The magnetic field penetrates an electrode member having at least one annular groove concentrically disposed at a depth sufficient to create a hollow cathode discharge within a closed magnetic field generated radially on the electrode. Generally, even in the absence of a magnetic field, if a groove is formed in the cathode, the discharge plasma will enter the groove, creating an intense discharge plasma called hollow cathode discharge. Although this is known to occur, the above configuration allows hollow cathode discharge and magnetron discharge to occur, thereby making it possible to obtain stable discharge even at low pressure.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to FIGS. 1 to 7.

FIG. 1 shows an embodiment of the present invention, in which magnets 2, 2 are fixed to the center and outer periphery of the upper surface of a disc 1 made of a magnetic material such as iron. A disc-shaped target 3 is arranged on the upper surface side of the target 2. As shown in FIG. 2a, a plurality of concentric grooves 4, 4, . . . are formed on the upper surface of the target 3, and a power source 5 is connected to the target 3. Note that the number of the grooves 4 may be one, and the number of the grooves 4 may be one.
may be formed into a rectangular shape to form concentric grooves 4, as shown in FIG. 2b.

In this embodiment, the discharge electrode constructed as described above is placed in a vacuum container, and a workpiece (not shown) is placed at a position facing the target 3. By applying a high voltage between the object to be processed and the target 3 from the power source 5, electrons move inside the groove 4 and an electric field is generated, as shown by the broken line in FIG. 2a. Plasma 6 generated by the magnetron is generated in a portion perpendicular to the radial magnetic field A generated by the magnet 2, that is, inside the groove 4.
occurs. The plasma 6 bombards the inner surface material of the target 3 with ions, thereby depositing it on the object to be treated.

Therefore, in this embodiment, as shown in FIG. 3, a hollow cathode discharge and the magnetron discharge are generated inside the groove 4, and electrons are confined in the groove 4 portion of the target 3, so that the plasma 6 The discharge becomes stable. Also, groove 4 of target 3
Since all of the grooves 4 function as spatter sources, by increasing the number of grooves 4, it is possible to increase the number of spatter sources within the same plane, thereby making it possible to form a more uniform film.

Incidentally, a taper expanding upward may be formed on the side surface of the groove 4 of the target 3.

Further, FIG. 4 shows another embodiment of the present invention, in which a target 3 is formed in a cylindrical shape, and inside this target 3, a plurality of annular magnets 2,
2 are arranged at predetermined intervals in the axial direction, and a plurality of annular grooves 4, 4, .

In this embodiment, an axial magnetic field A is generated by the magnet 2, and a high voltage is applied between the target 3 and the workpiece (not shown).
An electric field is generated inside the grooves 4, 4..., and the grooves 4, 4...
Generate plasma inside.

Therefore, in this example, as in the above example, stable plasma discharge can be obtained even with a ferromagnetic target, and furthermore, since the spatter source is uniform in area, the workpiece can be uniformly distributed. This makes it possible to form a film.

Furthermore, FIG. 5 shows another embodiment of the present invention, in which target support members 7, 7, . It is arranged in the shape of
Annular targets 3, 3, . . ., each having a substantially U-shaped cross section and a groove 4 formed inside, are removably fitted into the gaps between the target support members 7, 7, .

In this embodiment, as in the above-mentioned embodiments, a uniform film can be formed on the object to be treated, and the targets 3, 3, . . . can be replaced extremely easily. Furthermore, if the targets 3, 3, . . . are formed of different materials, it becomes possible to easily form an alloy film.

Further, FIG. 6 shows another embodiment of the present invention, in which a target 3 made of a ferromagnetic material is placed on the upper surface side of the magnet 2 with a predetermined gap in the radial direction, and this gap portion acts as a groove. An insulating plate 8 made of a quartz plate or the like is disposed below the gap.

In this embodiment, even if the target material is made of a ferromagnetic material, the lines of magnetic force do not pass through the inside of the target 3, and each target 3, 3, . . .
Since the magnetic field A is generated in the gap portion, it is possible to reliably and uniformly generate plasma in the groove, that is, the gap portion.

Incidentally, as shown in FIG. 7, a taper may be formed on the side surface of the target 3, so that the target material is smoothly scattered upward.

〔Effect of the invention〕

As described above, the discharge electrode according to the present invention has at least one annular groove concentrically arranged in a closed magnetic field generated radially with a depth sufficient to generate a hollow cathode discharge. parts,
The magnetic field is disposed so as to penetrate through the groove, and hollow cathode discharge and magnetron discharge are generated in the groove, so even if the electrode member is made of ferromagnetic material, stable plasma discharge can be achieved. Further, since plasma is generated uniformly in the groove portion, it functions as a flat and uniform electrode member, and has effects such as being able to form a uniform film on the object to be processed.

[Brief explanation of drawings]

1 to 7 each show an embodiment of the present invention, FIG. 1, FIG. 4, and FIG. 7 are longitudinal sectional views, respectively, and FIGS. 2a and 2b are perspective views of the target, respectively. , FIG. 3 is a vertical cross-sectional view of a groove portion showing the discharge action by the hollow cathode, and FIGS. 5 and 6 are partial vertical cross-sectional views, respectively. 1...Disk, 2...Magnet, 3...Target, 4...Groove, 5...Power source, 6...Plasma,
7...Target support member, 8...Insulating plate.

Claims (1)

[Claims] 1. An electrode member having at least one annular groove disposed concentrically with a depth sufficient to cause a hollow cathode discharge in a closed magnetic field generated radially on the electrode is A discharge electrode characterized in that it is arranged so as to penetrate through the discharge electrode.