A New High Target Utilization Efficiency Planar Magnetron Sputtering Cathode

Abstract

The invention provides a novel plane magnetron sputtering cathode. The plane magnetron sputtering cathode comprises a target material, a backboard, a magnet device and a magnetic conductive plate. The target material is arranged at one side of the backboard, and the magnetic conductive plate is arranged at the other side of the backboard. The magnet device is arranged between the backboard and the magnetic conductive plate. The magnet device comprises a middle magnet and an outer ring magnet surrounding the middle magnet. The middle magnet comprises at least two electromagnets. The polarities of magnetic poles, facing the target material, of the outer ring magnet and the middle magnet are opposite. The plane magnetron sputtering cathode further comprises an electromagnet power source. The electromagnet power source is connected with the at least two electromagnets and supplies power to the at least two electromagnets in sequence so that magnetic field distribution between the outer ring magnet and the middle magnet can be changed continuously. By implementing the novel plane magnetron sputtering cathode, the target material utilization rate can be effectively increased, pollution to the target material is prevented, and stability of the sputtering speed is improved. In addition, the plane magnetron sputtering cathode provided by the invention has the characteristics of being simple in structure, easy to control and high in reliability.

Description

technical field [0001] The invention relates to the technical field of magnetron sputtering, in particular to a planar magnetron sputtering cathode. Background technique [0002] At present, in the application field of magnetron sputtering coating technology, the most widely used is the planar magnetron sputtering cathode. Please refer to figure 1 , figure 1 It is a schematic diagram of the working principle of the planar magnetron sputtering cathode in the prior art. Such as figure 1 As shown, an existing typical planar magnetron sputtering cathode includes a target 1 , a copper back plate 2 , a magnet device and a magnetically conductive plate 4 . Specifically, the target 1 is disposed on the copper back plate 2, wherein the side of the target 1 facing the external space is used for sputtering. The magnet device and the magnetic conductive plate 4 are arranged on the other side of the copper back plate 2 , wherein the magnet device is arranged between the back plate 2...

AI Technical Summary

Problems solved by technology

With the occurrence of sputtering, once the sputtering runway on the target is punctured, the target can no longer be used, and a new target needs to be replaced, resulting in a very low utilization rate of the target, usually only 30%~40%

The sputtering target is the main consumable of magnetron sputtering, and the low utilization rate will undoubtedly cause a great waste of the target, resulting in an increase in the cost of sputtering

[0006] Second, without changing the sputtering process conditions, as the sputtering runway 12 on the target 1 gradually deepens, the sputtering rate will gradually decrease

In practical applications, the coating process requires sputtering to maintain a stable rate. In view of this situation, if the existing planar magnetron sputtering cathode is used, it will have a certain impact on the quality of the coating process.

[0007] Third, some impurities will accumulate in regions other than the sputtering runway 12 on the target material 1 that are not bombarded by ions. During the coating process, the impurities on the surface of these regions will also partially Released and incorporated into the film, it will reduce the purity of the coating and form pollution

This method starts from the structure of the target instead of the structure of the planar magnetron sputtering cathode. Although the utilization rate of the target can be improved to a certain extent, there are still some problems.

First of all, since the thickness of the target is limited by the strength of the magnetic field, it cannot be thickened without limit, so the improvement of the utilization rate of the target is correspondingly limited, and the degree of improvement is about 5%-10%.

Secondly, changing the target material from flat to irregular shape increases the difficulty of target material processing and increases the cost of target material processing

In addition, this method still cannot avoid the problems of gradual reduction of the aforementioned sputtering rate and the formation of pollution.

[0010] The second method is to add magnets between the outer ring magnet and the center magnet to form multiple sputtering tracks. This method can increase the area of ​​the sputtering area a little, but the effect of improving the utilization of the target is also very limited, usually no more than 10%

[0013] First, since the high-speed rotating magnet is achieved mechanically, it is prone to rotation failure

In addition, due to the cooling water required to set the target around the magnet, it is also prone to water seal failure

Compared with the above-mentioned planar magnetron sputtering cathodes in which the magnets do not move, the sputtering cathodes using high-speed rotating magnets have lower reliability, more complex structures, and higher costs

[0014] Secondly, since the magnet rotates mechanically and is affected by the cooling water and water seal, the rotation speed of the magnet is limited to a certain extent, and it is difficult to reach more than 500 rpm

At this speed, if the material of the target is relatively brittle, such as some compound targets (ZnS, etc.), for a certain area of ​​the target, the time interval between two sputterings is relatively long, which is likely to cause the target Inconsistency in temperature leads to target cracking and unusable

[0015] Again, the method of high-speed rotating magnets is not widely applicable, and can only be applied to circular magnetron sputtering cathodes, but not to rectangular magnetron sputtering cathodes

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