JPH04358064A - Magnetron sputtering cathode - Google Patents

Abstract

PURPOSE:To prolong the life of a target and to improve the efficiency of using the target by subjecting the target to uniform sputtering. CONSTITUTION:The magnetron sputtering cathode constituted by disposing a magnet device in the rear part of a backing plate mounted with the target atop the plate is provided with ferric magnets 14, 15 magnetized in the directions opposite from the magnetic pole 6 in the central part of the magnet device and the magnetic pole 7 in the peripheral edge part thereof, respectively, by which the shape of the magnetic lines of force in the upper part of the target is shaped.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetron sputtering cathode for sputtering a non-magnetic target using a permanent magnet.

0002

2. Description of the Related Art There are various types of conventional magnetron sputter cathodes, one example of which is shown in FIG. A non-magnetic target 3 is attached to the upper surface of the backing plate 2 , and a magnet device 4 is disposed behind the backing plate 2 so as to exist inside the cathode case 1 . The magnet device 4 has a structure including a bottom yoke 5 made of iron, a central magnetic pole 6 made of a rare earth ferromagnet that stands up from the center of the bottom yoke 5, and a central magnetic pole 6 that stands up from the periphery of the bottom yoke.
It is made up of a central magnetic pole 6 and a peripheral magnetic pole 7 made of a ferrite magnet surrounding the central magnetic pole 6 in a ring or rectangular shape with a space therebetween. 7 and 8 show the structure of the magnet device 4 in detail. In addition, in FIG. 6, 8 is an earth shield, 9 is a vacuum chamber wall, 10 is an insulating material, and 11 is a cooling water pipe for flowing cooling water. In such a magnetron sputter cathode, an S pole is formed at the tip of the central magnetic pole 6, and an N pole is formed at the tip of the peripheral magnetic pole 7.
A magnetic field is generated between the target and the pole, and a part of the magnetic field forms curved lines of magnetic force 12 in the space near the surface of the target 3. FIG. 9 is a graph obtained by measuring the magnetic flux density BV in a direction perpendicular to the target 3 surface at a position X from the center on the target 3 surface of such a magnetron sputtering cathode. In this way, curved lines of magnetic force 12 are formed in the space near the surface of the target 3, so electrons in the plasma perform trochoidal motion along the lines of magnetic force 12 as shown in FIG.
The electron cloud 1 shown in FIG.
3 will be formed. As a result, Ar in the plasma
Ions are attracted to this electron cloud 13 and begin to sputter the target 3. Next, since other examples of conventional magnetron sputter cathodes have almost the same configuration as the one example shown in FIGS. 6, 7, and 8, many explanations thereof will be omitted, but FIG. As shown, the structure of the magnet device 4 is slightly different from the first example. That is, as shown in FIG.
The peripheral magnetic pole 7 is made of a thin rare earth strong magnet. FIG. 13 is a graph obtained by measuring the magnetic flux density BV in a direction perpendicular to the surface of the target 3 at a position X from the center on the surface of the target 3 in another example.

0003

[Problems to be Solved by the Invention] In one example of a conventional magnetron sputtering cathode, curved lines of magnetic force 12 are formed in the space near the surface of the target 3 as described above, but the magnetic flux in the direction perpendicular to the surface of the target 3 is Density BV
Since the region where the magnetic field becomes approximately 0 Gauss is narrow and the magnetic field lines 12 are curved steeply, a high-density electron cloud 13 is formed at the top of the curved magnetic field lines 12. As a result, as shown in FIG. 11, only the center portion of the target 3 is sputtered, and the target 3 becomes lopsided. Therefore, the target 3 reached the end of its life with most of it remaining, causing problems such as a decrease in its usage efficiency. Next, in another example of the conventional magnetron sputter cathode, the magnet device 4 has a peripheral magnetic pole 7 made of a thin rare-earth ferromagnet, so that the magnetic flux in the direction perpendicular to the surface of the target 3 is generated as shown in FIG. The region where the density BV is almost 0 Gauss is slightly wider than in the first example above, but
Since this was not sufficient as before, the same problem as in the case of the first example above occurred. An object of the present invention is to provide a magnetron sputtering cathode that solves the above-mentioned conventional problems and can extend the life of the target by uniformly sputtering the target and improve its usage efficiency. .

0004

[Means for Solving the Problems] In order to achieve the above object, the present invention includes a central magnetic pole made of a rare earth ferromagnet, and a rare earth ferromagnetic pole surrounded by a ring or square shape with a spacing therebetween. A magnet device having a peripheral magnetic pole made of a magnet is disposed behind a backing plate on which the target is attached to the upper surface, and the central magnetic pole and peripheral magnetic pole of the magnet device create a curved space near the surface of the target. In a magnetron sputtering cathode that forms magnetic field lines and thereby generates a high-density plasma to sputter a target, each of the central magnetic pole and peripheral magnetic pole of the magnet device is magnetized in the opposite direction. The present invention is characterized in that the magnetic lines of magnetic force are shaped by arranging ferrite-based magnets adjacent to each other.

[0005]

[Operation] In this invention, a ferrite magnet magnetized in the opposite direction is placed adjacent to each of the central magnetic pole and the peripheral magnetic pole of the magnet device, so that there is a gap between the central magnetic pole and the peripheral magnetic pole. A part of the lines of magnetic force formed by the ferrite magnet will be absorbed by the ferrite magnet. Therefore, the shape of the magnetic field lines formed in the space near the target surface is shaped,
The magnetic flux density BV in the direction perpendicular to the target surface is almost 0
The Gaussian region becomes wider.

[0006]

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings. An embodiment of the present invention is shown in FIG. 1, in which a conventional magnetron sputter cathode is improved and a magnetron sputtered cathode is installed around a central magnetic pole 6 made of a rare earth ferromagnet. A ferrite magnet 14 is provided at the ferrite magnet 14, and a ferrite magnet 15 is also provided inside and adjacent to the peripheral magnetic pole 7 made of a rare earth ferromagnet. The ferrite magnet 14 is magnetized in the opposite direction to the central magnetic pole 6, and the ferrite magnet 14 is magnetized in the opposite direction to the central magnetic pole 6.
5 is also magnetized in the opposite direction to the peripheral magnetic pole 7. The magnet device 4 has a width W of 232 mm, a width W of a central magnetic pole 6 and a peripheral magnetic pole 7 made of rare earth strong magnets of 4 mm, and a thickness of ferrite magnets 14 and 15 of 6 mm. The ratio of the width W of 4 and the width w of the central magnetic pole 6 and the peripheral magnetic pole 7 made of rare earth ferromagnets is preferably designed to be between 80:1 and 20:1. 2 and 3 show the structure of the magnet device 4 in detail. FIG. 4 is a graph obtained by measuring the magnetic flux density BH in a direction parallel to the target 3 surface and the magnetic flux density BV in a direction perpendicular to the target 3 surface at a position X from the center on the target 3 surface. In addition, FIGS. 1, 2, and 3 show a conventional magnetron sputter cathode with other symbols in FIG. 6.
, 7 and 8 are the same as those in FIG. 7 and FIG. 8, and their explanation will be omitted. In such an embodiment, a ferrite magnet 14 is provided around and adjacent to the central magnetic pole 6 made of a rare earth ferromagnet, and a ferrite magnet 14 is provided inside the peripheral magnetic pole 7 made of a rare earth ferromagnet. , a ferrite magnet 15 is provided adjacent to this, and the ferrite magnet 14 is further magnetized in the opposite direction to the central magnetic pole 6, and
Since the ferrite magnet 15 is also magnetized in the opposite direction to the peripheral magnetic pole 7, a portion of the magnetic lines of force 12 formed between the central magnetic pole 6 and the peripheral magnetic pole 7
5 will be absorbed. Therefore, the shape of the magnetic lines of force 12 formed in the space near the surface of the target 3 is shaped, and the region where the magnetic flux density BV in the direction perpendicular to the surface of the target 3 is approximately 0 Gauss is expanded. Therefore,
As shown in FIG. 5, the electron cloud 11 also spreads, and the target 3 is evenly sputtered. Incidentally, in the above embodiment, the material of the target 3 may be a non-magnetic material such as Al, Cu, or Cr, or a non-magnetic alloy such as Fe-Al or Al-Si. Moreover, the shape of the target 3 may be round or square.

[0007]

According to the present invention, the target can be sputtered evenly, so that the following effects can be achieved. ■The life of the target is extended, resulting in less frequent replacement of the target and improved operating rate of the sputtering equipment. ■ Target usage efficiency is improved and running costs of sputtering equipment can be significantly reduced. ■The area where uniform film thickness distribution can be obtained is expanded. ■It is possible to reduce changes in sputtering characteristics (range in which a uniform film thickness can be obtained, etc.) over time from the initial stage of use to the final stage of use of the target.

[Brief explanation of the drawing]

[Fig. 1] A sectional view showing an embodiment of the present invention.

[Fig. 2] A cross-sectional view of a magnet device used in an embodiment of the present invention.

FIG. 3 is a plan view of a magnet device used in an embodiment of the present invention.

FIG. 4 is a graph showing the magnetic flux density on the target surface in an example of the present invention.

FIG. 5 is an explanatory diagram showing a state in which a target is evenly sputtered in an embodiment of the present invention.

[Fig. 6] A cross-sectional view showing an example of a conventional magnetron sputter cathode.

[Fig. 7] A cross-sectional view of a magnet device used in an example of a conventional magnetron sputter cathode.

FIG. 8 is a plan view of a magnet device used in an example of a conventional magnetron sputter cathode.

FIG. 9 is a graph showing the magnetic flux density on the target surface in an example of a conventional magnetron sputtering cathode.

[Figure 1
0] Explanatory diagram showing the principle of formation of an electron cloud in an example of a conventional magnetron sputter cathode

FIG. 11 is an explanatory diagram showing a state in which a target is partially dug in an example of a conventional magnetron sputtering cathode.

FIG. 12 is a sectional view showing another example of a conventional magnetron sputter cathode.

FIG. 13 is a graph showing the magnetic flux density on the target surface in other examples of conventional magnetron sputter cathodes.

[Explanation of symbols]

2...Backing king plate 3...
・Target 4...Magnet device 6...Central magnetic pole 7...Peripheral magnetic pole 14...Ferrite magnet 15...Ferrite magnet

Claims (1)

[Claims] Claim 1: A magnet device having a central magnetic pole made of a rare earth strong magnet and a peripheral magnetic pole made of a rare earth strong magnet surrounding the center magnetic pole in a ring shape or a square shape with a space therebetween, with the target facing upward. The central magnetic pole and peripheral magnetic pole of the magnet device form curved lines of magnetic force in the space near the surface of the target, thereby generating high-density plasma. In a magnetron sputtering cathode for sputtering a target, a ferrite magnet magnetized in the opposite direction is arranged adjacent to each of the central magnetic pole and the peripheral magnetic pole of the magnet device to shape the shape of the magnetic lines of force. A magnetron sputter cathode featuring: