JPS5989769A - Planar magnetron type sputtering electrode - Google Patents

Abstract

PURPOSE:To improve the utilizing efficiency of a target material by forming a cusp magnetic field on the target to confine the atom necessary for sputtering so that almost the whole surface of the target can be sputtered. CONSTITUTION:A sputtering electrode is constituted by using a target 5, a backing plate 7, a back plate 8 and a magnet 6 as main constituting elements. The magnet 6 is disposed around the target 5 so that the side facing to the target 5 has the same polarity and that the magnetic fields facing to each other on the target 5 are reversed from each other, thereby forming a cusp magnetic field. The magnet 6 for forming the cusp magnetic field may be a permanent magnet or electromagnet. Then high speed sputtering arises on almost the whole surface of the target 5 and the fairly wide part of the material of the target 5 can be effectively used.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a planar magnetron type sputtering electrode used in a sputtering apparatus for forming a thin film, and particularly to a sputtering electrode with high target material utilization efficiency.

[Prior art]

FIG. 1 shows an example of a conventional planar magnetron type sputter electrode. In the figure, 1 is a region eroded by sputtering, 2 is a line of magnetic force, 3 is an electric field, 4 is a locus of electron movement, and 5 is a target.

In this sputtering electrode, a magnetic field as shown by magnetic lines of force 2 is formed, and electrons move in this magnetic field and electric field 3 while drawing a cycloid trajectory, efficiently ionizing rare gas atoms to cause sputtering.

Therefore, in the target 5 subjected to sputtering, the erosion region 1 corresponding to the portion with high electron density is intensively eroded, and the other portions are hardly eroded. Moreover, as the erosion progresses, this tendency becomes stronger due to the appearance of a stronger magnetic field, and the speed of erosion increases at an accelerating rate. In the end, the life of the target 5 is until the maximum depth of the eroded region 1 becomes equal to the thickness of the target 5. Therefore, the portion of the target material that is actually sputtered is very small, and the material utilization efficiency is extremely low. In order to improve this drawback, there are examples of attempts to make the eroded area uniform by mechanically moving a magnet installed on the back side or by installing a double-pole electromagnet to move the magnetic field. , the structure of the electrode becomes complicated.

This required an electromagnet control device, which caused problems in terms of cost and failure rate.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a Z-lenor magnetron type sputtering electrode that has a simple structure and is capable of high-speed sputtering with high target material utilization efficiency.

[Summary of the invention]

The present invention uses a planar magnetron type sputtering electrode to form a cusp magnetic field on the target to confine the electrons necessary for sputtering, and to sputter almost the entire surface of the target, thereby improving the efficiency of use of target material. This is the main point, and will be explained in more detail below.

The planar magnetron method, in which the movement of electrons is controlled by a magnetic field to cause high-speed sputtering, has extremely high ionization efficiency because it can ionize multiple argon atoms with one electron.

However, since this magnetic field is quite local, localized sputtering occurs. Therefore, if the distribution of the magnetic field is devised so that sputtering occurs over the entire surface of the target, the target material can be used without wasting it. Such a magnetic field needs to be uniformly distributed directly above the target surface, but in order to achieve such a magnetic field, a strong magnet must be placed at a position more than 1 force away from the back surface force of the target. σ), which is not practical. Therefore, in order to easily realize a magnetic field as uniform as possible by devising the arrangement of magnets, etc., in the present invention, the cusp magnetic field that is used to maintain plasma in a mirror-type fusion reactor is reduced. Make use of it. FIG. 2 is a schematic diagram of a cusp magnetic field, but the magnetic fields on the axes created by the two magnets 60 are in opposite directions, and the magnetic forces @2° between the magnets press each other against each other. Therefore, the direction of the force applied to the electrons emitted from the surface of the target 5 is opposite between the right half and the left half of the target 5, and depending on the direction of the magnetic field lines 2, the right half moves toward the front of the screen, and the left half moves toward the front of the screen. The car moves in a cycloid trajectory towards the other side of the screen (or vice versa). In addition, the electrons emitted directly above the target (5σ) central force escape to the outside through a bundle of magnetic lines of force, but this is small in quantity, and the space in which the electron force can be confined is 7'% in Figure 2. Since the portion A is rounded, the probability of ionization of the rare gas, which is the snow ivy gas, in the central portion is sufficiently large even in consideration of electron leakage. Furthermore, since the direction of electron movement on the target is opposite between the right and left halves, if the direction of the electrons can be changed by 180° at both ends of the target, the time it takes for the electrons to be confined in the magnetic field is The length should increase, and the ionization efficiency should increase.

In order to realize this idea, in the present invention, as shown in FIG. 3, a magnetic field is set at right angles to the cusp magnetic field. By adopting such a configuration, electrons move in a closed loop, and the ionization efficiency for the sputtering gas is improved. explain. FIG. 4 is an explanatory diagram showing each component necessary for the configuration of the present invention. The main components are the vine electrode 1, the target 5, the backing plate 7, the back plate 8, and the magnet 6. By arranging the magnets 6 and 5 around the target 5 so that the magnets facing the target have the same polarity,
The opposing magnetic fields on the target are directed in opposite directions to form a cusp magnetic field. Note that the magnet 6 for forming the cusp magnetic field may be a permanent magnet or an electromagnet.

Next, individual examples will be described.

Example 1+ In this example, as shown in FIG.
This is an example in which two magnets 6 are arranged to face two opposite sides of the magnetic field, respectively, to form a cusp magnetic field. In this case, electrons tend to escape from the side of the Couget 5 where the magnet is not arranged, but the leakage of electrons can be suppressed to some extent by the magnetic field from the end of the magnet.

Embodiment 2: In this embodiment, in order to prevent the leakage of electrons described in Embodiment 1, as shown in FIG. This is an example in which a cusp magnetic field is formed by arranging . The state of the magnetic field in this embodiment is as shown by the magnetic force 1M2 in FIG. 3, and the electrons move in a rectangular locus with rounded corners and are confined in the magnetic field. Therefore, the ionization efficiency of electrons with respect to the sputtering gas is high, and sputtering can be performed at a higher speed.

Example 31 In this example, as shown in FIG.
This is an example in which a quasi-conical cusp magnetic field is formed by arranging magnets 6 around the magnet 5 with point-symmetrical two opposing points whose magnetic fields are 1j in opposite directions. In this case, the trajectory of the electron's motion is circular, and the center of the circle is on the axis vertically descending from the apex of the conical cone of the magnetic field. High ionization efficiency for sputtering gases.

Although each of the embodiments described above deals with a rectangular or circular target, the cusp magnetic field according to the present invention can be formed in a space above a target of any shape.

〔Effect of the invention〕

As explained above, Trap 1 According to the present invention, high-speed sputtering occurs on almost the entire surface of the target in a planar magnetron sputtering electrode, so a fairly wide area of the target material (2 (approximately twice as much) can be used effectively. Therefore, the life of the target is extended and the frequency of replacing the target is reduced, so that costs can be significantly reduced in the thin film forming process. In addition, since the sputter electrode according to the present invention does not require a complicated mechanism or control device, the manufacturing cost is low, and there is no failure.
From this point of view as well, cost reduction can be promoted.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram showing the magnetic field and movement of electrons in a conventional planar magnetron type sputtering electrode, Fig. 2 is an explanatory diagram showing a cusp magnetic field, and Fig. 3 is an explanatory diagram showing the cusp magnetic field in the implementation of the present invention in which the cusp magnetic field is applied to the sputtering electrode. An explanatory diagram showing an example, Fig. 4 is an explanatory diagram showing each component necessary for the present invention, Fig. 5 is an explanatory diagram showing an embodiment of the present invention in which a cusp magnetic field is applied to a rectangular target, and Fig. 6 is a circular diagram. FIG. 2 is an explanatory diagram showing an embodiment of the present invention in which a cusp magnetic field is applied to a target. Explanation of symbols 1... Erosion area by sputtering 2... Lines of magnetic force 6... Electric field 4... Trajectory of electron movement 5... Target 6. 6... Magnet 7... Backing plate 8. ...Seiban Patent Attorney Susuki 1) Li i') Kaya / Tsukaya Figure 2 4 Zuei 5th

Claims (1)

[Claims] (1) A magnetic pole consisting of a permanent magnet or a magnet is placed around the target flat plate on the side that forms the first main surface, which is the surface that receives sputtering, from the target flat plate made of the material to be sputtered. The same magnetic pole tips are aligned in the direction of the first main surface of the target flat plate, and a magnetic field parallel to the first plane of the target flat plate is generated from the periphery of the target flat plate toward the center of the target flat plate. ,
A planar magnetron type sputtering electrode, characterized in that the magnetic pole is arranged so that glow discharge plasma is confined on the target flat plate by the magnetic field. (2. In the planar magnetron type sputtering electrode according to claim 1, at the center of the second main surface side opposite to the first main surface of the target flat plate, the periphery of the first main surface is A planar magnetron type sputtering electrode characterized in that a second magnetic pole made of a magnet or a soft magnetic material is arranged so as to absorb a part of the magnetic field lines forming a magnetic field generated by the magnetic pole pressure arranged in the planar magnetron sputter electrode. .