JPS63282262A - Method for controlling sputtering device - Google Patents

Abstract

PURPOSE:To enlarge and erosion region and to form a film having uniform thickness by controlling a combination of the actions of the respective electromagnets of a cathode made up of plural electromagnets placed on the rear of a flat target to change the magnetic field on the front of the target by simple device and driving mechanism. CONSTITUTION:Seven electrodes 2, for example, are arranged on the rear of a backing plate 3 in an row at regular intervals in the direction of the major axis of the target 4, and fixed to a nonmagnetic plate 11. The lead wires taken out from the electrodes of the respective electromagnets 2 are brought out through a pipe 12, and connected to a switching power source on the outside. A DC or AC power is impressed between the cathode made up of the electromagnets 2 and the substrate 10 in opposition thereto. The plasma in he glow discharge of the device is highly densified by the turning on and off the seven electromagnets, and he inversion of the generated magnetic poles is carried out by the operation of the external switching power source.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to magnetron sputtering apparatus, and more particularly to a method for increasing the erosion area of a sputtering source.

2. Description of the Related Art FIG. 6 shows an electrode portion of a conventional magnetron type sputtering apparatus. A permanent magnet 15 having a Σ-shaped cross section is arranged inside the cathode box 1 . The permanent magnet 1
6 is not shown in the figure, but is movable in the direction of the arrow by a drive mechanism.

A target 4, which is a film forming material, is attached above the permanent magnet 15 via a backing plate 3.

6.7 is a pipe for supplying and discharging cooling water to prevent the target 4 from being heated. 5 is an anode, which is usually attached to the casing 8 and has a ground potential. Reference numeral 9 is an insulator, which insulates between the cathode box 1 and the casing 8. A high negative potential is applied to the cathode box 1. 10 is a substrate on which a film is to be formed, which is placed parallel to the target 4.

In the conventional electrode structure, the permanent magnet 15 forms a tunnel-like closed magnetic field as shown at 13 on the surface of the target 4. Therefore, the electrons ejected from the target 4 are confined by the electric and magnetic fields between the anode 5 and the target 4, and ionize the gas near the surface of the target 4 at high density. As a result, since the target 4 is bombarded with many ions, the amount of film-forming material that is ejected also increases, and the film is formed on the substrate 10 at a high speed.6 However, as described above, electrons are absorbed by the surface magnetic field 13 and Since the gas is confined in a region perpendicular to the electric field, the region where the gas becomes plasma at high density is also limited to this range. Therefore, the area of the target 4 that receives sputtering is also limited to the area where the high-density plasma exists. The area that receives sputtering is called an erosion area. Since the surface near the target on the pole of the permanent magnet 15 is not sputtered, an erosion region is formed on the part between the poles of the permanent magnet.

By the way, as mentioned above, in the conventional magnetoconsbattering device, the erosion region is limited by the shape of the permanent magnet, so there is a problem that the target cannot be consumed effectively. In order to solve this problem, some ideas have been devised to change the distribution of the magnetic field existing on the target surface, and as a means to do so, mechanically moving the position of the permanent magnet as shown in FIG. A method of enlarging the area, a method of installing a second permanent magnet outside the permanent magnet, and a method of mechanically moving the second permanent magnet are considered.

FIGS. 7a and 7b show two lotion areas on the target surface according to such a conventional method. In the figure, an erosion region 14 surrounded by a dotted line is when the permanent magnet is stationary, and an erosion region 1 surrounded by a dashed line
4 is a case where the permanent magnet is moved in the direction of the arrow.

Problems to be Solved by the Invention 2. Conventional magnetron type sputtering equipment that aims to effectively consume the target by changing the region and shape of the lotion, such as a method of mechanically moving the permanent magnet, and a method of mechanically moving the permanent magnet. In the method of operating the second permanent magnet on the outside of the magnet, there are problems in that the drive mechanism is complicated and the device becomes large. Further, in order to efficiently consume the entire surface of the target, a more complicated drive mechanism is required, so the current method of moving the permanent magnet must be simple. As a result, there is a problem that control of the two lotion areas becomes insufficient. For example, as in the erosion region 14 shown in FIG. 7, targets on the permanent magnet often remain uneroded forever.

The present invention solves these problems, and aims to expand the erosion area and form a uniform film by changing the magnetic field on the target surface using a simple device and drive mechanism. do.

Means for Solving the Problems In view of the problems of the prior art, the present invention provides a structure in which a cathode consisting of a flat plate target and a magnet installed on the back surface of the target is provided, and a substrate facing the cathode. It has a function of applying DC or AC power to magnetically move a concentrated area of generated plasma to increase the erosion rate of the sputtering source, and the magnet is composed of a plurality of electromagnets, and each electromagnet is The magnetic flux density distribution on the target is changed by controlling the combination of operations.

Function The electromagnet used in the present invention is placed in the cathode box.
It is small enough to fit within a minute, and the electrodes can be easily removed. Therefore, instead of mechanically moving the electromagnets themselves to be operated, the number of electromagnets to which voltage is applied and the applied voltage among the plurality of installed electromagnets can be electrically switched using an external switch, as described above. In addition, the same effect as that obtained by mechanically moving a permanent magnet can be obtained.

Moreover, the device does not become larger in any way.

Example An embodiment of the present invention will be described below based on the drawings.

FIG. 1 is a sectional view of an electrode portion of an embodiment of the present invention. 2 is an electromagnet installed on the back surface of the backing plate 3, and in this embodiment, a total of seven electromagnets are installed on the target 4.
They are arranged in a row at equal intervals in the long axis direction. 11 is a non-magnetic plate to which the electromagnet is attached. 12 is a pipe for taking out the lead wires taken out from the electrodes of the seven electromagnets to the outside of the cathode box;
The lead wire taken out from the is connected to an external switching power source. Other parts that are the same as those in FIG. 4 are given the same numbers.

Next, the method of operating the sputtering apparatus of this embodiment will be continued. The densification of plasma during glow discharge in the sputtering apparatus according to this embodiment is achieved by turning on and off the seven electromagnets.
The FF and the reversal of the generated magnetic pole are performed by operating an external switching power supply. Examples of operation are shown in FIGS. 2 to 4. In these figures, the seven electromagnets are numbered 1 to 7 to distinguish them from each other. In Figure 2, all electromagnets 1 to 7 are connected: 1.3, 6.7 are N poles, 2, 4. Fig. 2 shows the magnetic field that appears on the surface of the target when it operates so that e becomes the south pole, and Fig. 2 shows the erosion area at this time. At this time, the targets directly above all of the electromagnets 1 to 7 remain without being sputtered.

Figure 3a shows the case where 1°5 is the N pole, 3 and 7 are the S poles, and the other electromagnets are not operated. At this time, the second lotion area becomes as shown in Figure 3, and the targets on the electromagnets 2 and 4.6 that remained unsputtered in Figure 2 are sputtered. Furthermore, FIG. 4a shows the case where 1 and 7 are N poles, 4 is S pole, and the other electromagnets are not operated. This time, the targets on the three and four electromagnets that were not sputtered in FIG. 3 & are sputtered. By performing sputtering while appropriately switching the electromagnet and its polarity, the area of the target that remains unsputtered can be reduced.

Furthermore, compared to sputtering using only the operation shown in Figure 4a, it is better to perform sputtering by combining the operations shown in Figures 2 and 3 because the erosion area is evenly distributed over the entire surface of the target used. A uniform film can be formed.

Next, the operation of the permanent magnet will be described based on FIG. 6. In FIG. 5, the number of permanent magnets installed is six. (Each electromagnet is numbered 1 to 5 and its position is fixed.) Figure 5a shows the case where all five electromagnets are operated. The target on the electromagnet in 3.4 remains uneroded. Figure 6 shows Sections 1.3.
If five electromagnets were operated, the target on the third electromagnet between each two lotion areas would remain the only uneroded area. In addition, in order to make the target on the third electromagnet into the two lotion area, one possible method is to operate the second and fourth electromagnets as N and S poles, respectively, without operating the third electromagnet. . By switching the operating position and magnetic field of the electromagnet in this way, it is easy to set a target area on the target as an erosion area.

(In a structure using permanent magnets, the target on the permanent magnet is not eroded at all.) Furthermore, since the position of the electromagnet used and the timing of switching the magnetic field can be precisely controlled, it is more effective than conventional methods. A uniform film can be obtained.

As described above, the structure of the present invention simplifies the mechanism for moving the magnetic field passing above the target and expands the moving area, which makes conventional devices larger, less efficient, and insufficiently controlled. problem is resolved.

Effects of the Invention As described above, according to the present invention, the ON/OFF and polarity of the plurality of electromagnets housed in the cathode box can be controlled simply by operating an external switching power supply, thereby eliminating the complicated conventional method. The same effect as that obtained by moving a permanent magnet using a drive mechanism can be easily obtained. Furthermore, in the conventional method using a permanent magnet, sputtering can be performed even in the non-erosion region (the target portion on the top of the permanent magnet), which necessarily exists, so that the effect of increasing the target usage efficiency can be obtained. Furthermore, by selecting the operation pattern of the electromagnet, it is possible to obtain a more uniform film.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a magnetron type sputtering apparatus according to an embodiment of the present invention, and FIGS. An explanatory diagram showing the magnetic field and the two lotion areas, FIGS. 6a and b are explanatory diagrams showing the magnetic field formed by the electromagnet and the two lotion areas on the target, and FIG. 6 is a cross-sectional view of the sputtering ta of a conventional magnetron sputtering device. FIGS. 7a and 7b are explanatory views showing permanent magnets and erosion areas of a conventional magnetron type sputtering apparatus. 1...Cathode box, 2...Electromagnet, 3...Backing plate, 4...
・Target, 5... Anode, e...
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...Casing, 9...Insulator, 10...
...Substrate to be film-formed, 11...Nonmagnetic material, 12...
...Pipe for taking out lead wires. Name of agent: Toshio Nakao and 1 other person! −
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Claims (1)

[Claims] A concentrated area of plasma generated to increase the erosion rate of the sputtering source by applying DC or AC power between a cathode consisting of a flat target and a magnet installed on its back surface and a substrate facing the cathode. The plasma concentration area is moved by changing the number of electromagnets that apply voltage and the applied voltage among a plurality of electromagnets provided on the back surface of the target. Control method for sputtering equipment.