JPH0660393B2 - Plasma concentrated high-speed sputter device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma-concentrated high-speed sputtering apparatus for film deposition such as semiconductor process technology and surface treatment technology.

Configuration of Conventional Example and Problems Thereof In recent years, a high-speed sputtering apparatus capable of forming a high-quality thin film at a higher speed has been required along with the speeding up of processes such as semiconductors.

The conventional high speed sputtering apparatus will be described below.

FIG. 1 is a configuration diagram of a conventional high-speed sputtering apparatus, 1 is a vacuum chamber, 2 is a target provided in the vacuum chamber 1, 3 is a magnetic field parallel to the target 2, and 4 is a permanent magnet for generating a magnetic field 3. 5 is a substrate arranged to face the target 2; 6 is an electric field orthogonal to the magnetic field 3; 7 is a power source for generating the electric field 6;
Reference numeral 8 is an introduction gas for generating plasma, and 9 is a substrate 5.
The sample 10 fixed to is a yoke constituting a magnetic circuit of the permanent magnet 4.

The operation of the high speed sputtering apparatus configured as described above will be described below.

Magnetic field 3 parallel to the target 2 surface near the target 2 surface
Is obtained by the permanent magnet 4. An electric field 6 orthogonal to the magnetic field 3 is obtained between the target 2 and the substrate 5 by the power supply 7. Due to the magnetic field 3 and the electric field 6 which are orthogonal to each other, the electrons in the discharge region are trapped by the space charge and the magnetron discharge is caused from the introduced gas 8. By increasing the plasma density in the vicinity of the target 2 with the permanent magnet 4, the sputtering effect is enhanced, and film deposition can be performed at high speed.

However, in the above-described conventional configuration, the magnetic field 3 is weak and non-uniform because an unnatural magnetic gap that uses a magnetic field is also used as the magnet configuration. Therefore, the film deposition rate was not satisfactory, and only a part of the target 2 was extremely consumed and the film deposition uniformity was not sufficient.
Further, there is a problem that a magnetic body cannot be used as the target 2 due to the magnetic circuit.

An object of the present invention is to solve the above-mentioned conventional problems, and to provide a plasma-concentrated high-speed sputtering apparatus capable of obtaining a uniform film deposition at high speed and using a magnetic material as a target. To aim.

The apparatus of the present invention comprises a vacuum chamber, a target arranged in the vacuum chamber, a sample arranged to face the target, and a peripheral portion of the vacuum chamber. A plasma source that radiates plasma in the horizontal direction with the target and the sample and that is composed of a ring-shaped cathode and two intermediate electrodes; A row of coils arranged so as to be sandwiched, an anode arranged in the vicinity of the target, and a magnet arranged under the target for bending the plasma in a direction perpendicular to the target and concentrating the plasma on the target. , Said cathode, two intermediate electrodes, 1
The pair of coils are sequentially arranged from the outer periphery to the outside of the vacuum chamber, and currents are applied to the one row of coils in opposite directions, whereby uniform film deposition at high speed can be obtained. By arranging the permanent magnets around, the magnetic body can be used for the target.

Description of Embodiments An embodiment of the present invention will be described below with reference to the drawings.

[Embodiment 1] FIG. 2 shows the structure of a plasma-concentrated high-speed sputtering apparatus according to the first embodiment of the present invention. In FIG. 2, 11 is a vacuum chamber, 12 is a gas inlet, 13 is a discharge cathode, 14 is a first intermediate electrode, 15 is a second intermediate electrode, 1
6 is a magnet provided in the first intermediate electrode 14, 17 is a ring-shaped plasma source composed of the discharge cathode 13, the first intermediate electrode 14 and the second intermediate electrode 15, 18 is a coil, 19
Is an anode of the plasma source 17, 20 is a target, 21 is a rod-shaped magnet disposed below the target 20, and 22 is a sample disposed so as to face the target 20.

The operation of the plasma-concentrated high-speed sputtering apparatus of the first embodiment configured as described above will be described below.

First, when the ring-shaped plasma source 17 introduces, for example, argon as a gas to be ionized in the X direction from the plurality of gas inlets 12, a large area plasma is generated from the annular slit. A pressure difference is provided between the cathode region and the anode region by the two intermediate electrodes 14 and 15. For example, with Argon guns of 0.6 Pam ³ / sec, the cathode region was kept at about 40 Pa and the anode region (near the target 20) was kept at about 0.1 Pa. Due to the DC power supply 25, the potential difference between the cathode 13 and the first intermediate electrode 14 is, for example, 40 V,
The second intermediate electrode 15 has a discharge voltage of 35 V, and the second intermediate electrode 15 and the anode 20 have a discharge voltage of 20 V, for example. A cusp magnetic field created by two ring-shaped magnets 16 through which an equivalent current flows in opposite directions was used in order to secure a sufficient magnetic field strength for guiding the discharge in the two intermediate electrodes 14 and 15.

Plasma 23 horizontally radiated from the plasma source 17
In order to concentrate the discharge plasma flow 27 near the target 20, it is necessary to bend the discharge plasma flow 27 near 90 degrees. Target 20
Are arranged at right angles to the initial plasma flow and have a strong magnet 21 (for example, a rare earth magnet SmCo ₅ ) inside thereof. The surface of the target 20 and the surface of the magnet 21 are separated by about 2 cm so that they can be sufficiently cooled by water. Fig. 5 shows a cylindrical permanent magnet 21 of φ30 mm × 15 mm.
In this case, the distance dependence of the magnetic flux density is shown. In Figure 4,
The x-axis is taken along the initial plasma flow 27 (along the axis of the plasma source 17) and the y-axis is taken from the center perpendicular to the surface of the target 20.

A magnetic field is required to change the direction of the discharge plasma 23. Since the electron flow in the discharge plasma 23 has small energy and its motion is not heat (not unidirectional),
Using the method of bending along the magnetic field lines with a horizontal magnetic field B _x and the vertical magnetic field B _y. This method is suitable for concentrating the discharge power because the plasma flow 27 is bent while converging along the lines of magnetic force. Externally B _x from the structure of the _device, since it is difficult to generate strong B _y, the upper limit is generated in the energy of the electron current in the plasma fired horizontally. Plasma flow 27
The magnetic field at the point where bending the B _{y (gauss),} the plasma stream 2
If the average radius when 7 is a cylinder is a (cm) and the energy of the electron flow in the plasma is Ve (eV), Is. Equation (1) means that the cyclotron radius of electrons in the plasma 23 must be smaller than the radius of the plasma flow.

The magnetic field B _{x in the} x direction is obtained by the cusp magnetic field created by the two coils 18 in which current flows in opposite directions. The magnetic field 27 produced by the coil 18 is shown in FIG.
showed that. FIG. 6b is a schematic diagram showing the direction of the current flowing through the coil. The central magnetic field in the y direction by the coil 18 is zero, and the magnetic field B _{y in the} y direction is almost independently determined by the permanent magnet 21 in the target 20.

The relationship of B _x and B _y in order to obtain a uniform sputtering effect fast, how it was converged to bending way and target 20 surface of the plasma flow 27 comes to influence. For example, the surface of the target is 600 gauss, and the intersection of the x axis and the y axis is 1 gauss or less.

The magnetic field configuration inside the plasma source 17 is controlled by the ring-shaped magnet 16
With the coil 18, the magnetic field 28 shown in FIG. 6 or the magnetic field 29 shown in FIG. 7 can be obtained. In the magnetic field configuration shown in FIG. 6, the magnetic field 28 in the plasma diffusion region in the vicinity of the second intermediate electrode 15 can be sharply lowered. Therefore, a wide plasma flow 27 can be obtained. Further, in the magnetic field configuration shown in FIG. 7, the magnetic field 29 in the plasma diffusion region gradually decreases, so that a converged plasma flow 27 can be obtained. At this time, the target 20 is changed to the anode 19
By maintaining a negative potential with respect to, sputtering occurs.

As described above, according to this embodiment, by concentrating the plasma flow 27 directly above the bending target 20, the plasma density on the surface of the target 20 is increased and the film deposition rate can be increased. Further, by making the proper relationship of the magnetic field B _x and B _y, it is the better the uniformity of possible film deposition to improve the plasma uniformity on the target 20 surface.

Second Embodiment Hereinafter, a second embodiment of the present invention will be described with reference to the drawings.

FIG. 8 shows the structure of the plasma-concentrated high-speed sputtering apparatus according to the second embodiment of the present invention. In FIG. 8, 38 is a vacuum chamber, 39 is a gas inlet, 40 is a discharge cathode, 41 is a first intermediate electrode, 42 is a second intermediate electrode, 4
3 is a magnet provided in the first intermediate electrode 41, and 44 is the discharge cathode 40, the first intermediate electrode 41, and the second intermediate electrode 42.
A ring-shaped plasma source composed of and 45 is a coil,
46 is a target, 47 is a cylindrical anode of a plasma source 44 placed so as to surround the target 46, and 48 is a cylindrical anode 4
7 is a plurality of permanent magnets arranged on the surface, and 49 is a sample arranged facing the target 46. The difference from the plasma-concentrated high-speed sputtering apparatus of FIG. 2 is that the target 46 and the permanent magnet 48 are different.

The operation of the plasma-concentrated high-speed sputtering apparatus of the second embodiment constructed as above will be described below.

First, the plasma 50 horizontally radiated from the plasma source 44 is bent toward the target 46 by the cusp magnetic field generated by the coil 45. As shown in FIG. 9, the cusp magnetic field shifts the position where the magnetic field 53 becomes zero downward by changing the currents flowing through the two coils 45 (for example, 5 A for the upper coil and 3 A for the lower coil). You can The magnetic field 53 causes the plasma 5
0 is also bent downward.

In order to concentrate the downwardly bent plasma 50 right above the target 46, it is necessary to confine the plasma 50 in the vicinity of the target 46. As shown in FIG. 10, a plurality of permanent magnets 48 are arranged at equal intervals so that the N poles or S poles in contact with the outside of the non-magnetic cylindrical anode 47 are adjacent to each other. A cusp magnetic field 54 is generated near the surface of the target 46 to reflect electrons on the wall of the cylindrical anode 47 and confine the plasma 50. At this time, by keeping the target 46 at a negative potential with respect to the anode cylinder 47, sputtering occurs.

As described above, according to the present embodiment, the plasma 50 can be concentrated right above the target 46 by the cusp magnetic field 53 of the coil 45 and the cusp magnetic field 54 of the permanent magnet 48, and the target 46 and the permanent magnet 48 can be separated. By doing so, a magnetic material can be used for the target 46.

EFFECTS OF THE INVENTION According to the present invention, a high-density plasma is concentrated right above a target to obtain a uniform film deposition at a high speed. Further, by separating a permanent magnet from the target, a magnetic material can be used as the target. It is possible to realize an excellent plasma-concentrated high-speed sputtering apparatus that can obtain the effect.

[Brief description of drawings]

FIG. 1 is a block diagram of a conventional high-speed sputtering apparatus, FIG. 2 is a block diagram of a plasma-concentrated high-speed sputtering apparatus according to the first embodiment of the present invention, FIG. 3 is the same perspective view, and FIG. 5 is a schematic diagram showing the flow of FIG. 5, FIG. 5 is a characteristic curve diagram of the permanent magnet, FIGS. 6 a and b and 7 a and b are schematic diagrams showing a magnetic field, and FIG. 8 is a second embodiment of the present invention. 9A and 9B are schematic diagrams showing the same magnetic field, and FIG. 10 is a front view of the target portion. 17 ... Plasma source, 18 ... Coil, 20 ... Target, 21 ... Magnet, 22 ... Sample, 24 ... Sputtered object, 26 ... Exhaust port.

Claims (1)

[Claims] 1. A vacuum chamber, a target arranged in the vacuum chamber, a sample arranged to face the target, and a target arranged in the outer periphery of the vacuum chamber and the target and the sample in the vacuum chamber. A plasma source that radiates plasma in a horizontal direction and that is composed of a ring-shaped cathode and two intermediate electrodes, and an outer peripheral portion of the vacuum chamber that sandwiches the plasma flow emitted from the plasma source. A row of coils arranged in a row, an anode arranged in the vicinity of the target, and a magnet arranged below the target to bend the plasma flow in a direction perpendicular to the target and concentrate it on the target. The cathode, the two intermediate electrodes, and the pair of coils are arranged outside the vacuum chamber in order from the outer circumference, and currents flow in opposite directions to the coils in the one row. Plasma-intensive high-speed sputtering apparatus.