JPS63219579A - Sputtering device - Google Patents

Abstract

PURPOSE:To sputter-etching the sputtered particles deposited on an intermediate electrode at a low rate and improve the efficiency in forming a thin film, by using the intermediate electrode facing the magnetic field space between inner and outer targets as the cathode at a voltage lower than both targets. CONSTITUTION:The annular outside target 4a with the inner peripheral side facing a sputtering surface 12 as the sputtering surface 12a is arranged around the inside target 4 with the outer peripheral side as the sputtering surface 12. The magnetic field space 7 wherein plasma is produced when both targets 4 an 4a are sputtered is formed between both sputtering surfaces 12 and 12a. In the sputtering device of such a structure, the intermediate electrode 6 is provided on the rear sides of the targets 4 and 4a and opposed to the magnetic field space 7. In addition, the intermediate electrode 6 is used as the cathode at a voltage lower than both targets 4 an 4a, and sputter-etching is carried out at a rate lower than the rate at which the sputtered particles generated in the space 7 are deposited on the intermediate electrode 6. By this method, the deposition and absorption of the sputtered particles are prevented, and the efficiency in forming the specified thin film is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a sputtering apparatus used for producing a thin film of ferromagnetic material or the like in the production of magnetic recording media.

(Prior Art) Conventionally, this type of sputtering work has been carried out using a method as shown in FIG.
has been developed.

That is, in the case shown in the same figure, an inner target 4 and an outer target 4a each having a planar circular ring shape are arranged concentrically, and each sputtering surface 12.1 of both targets 4.4a is arranged concentrically.
A plasma space is generated in the magnetic field space section 7 between the magnetic field parts 2a and 2a.

Therefore, according to this means, the arrangement of the targets 4.4a is similar to that of the conventional so-called flat plate magnetron sputtering apparatus, which simplifies the apparatus configuration, and the sputtering operation is similar to that of the conventional facing target type sputtering apparatus. Based on the principle, sputtering can be performed efficiently in a low-pressure sputtering gas atmosphere, and the advantage is that target utilization efficiency is improved.

However, in the above type of apparatus, if the backing plate 1 is made to face the space 7 where plasma is generated as shown in FIG. 4, the backing plate 1 at the same potential as the target 4.4a Secondary electrons emitted into the space 7 are trapped near the surface of the backing plate 1 while moving through the EXB drift, increasing the plasma density in the vicinity. A sputtering phenomenon occurs based on the same principle as sputtering, and as a result, the backing plate 1
A problem arises in that the material components are mixed into the formed film on the surface of the substrate 13, resulting in a deterioration in the quality of the formed thin film.

Therefore, in the past, in order to solve the above-mentioned drawbacks, a method was adopted in which an anode 20 that prevents sputtering was provided below the space 7 between the targets 4 and 4a, as shown in FIG.

(Problems to be Solved by the Invention) However, in the conventional means, as a measure to prevent sputter erosion of the backing plate 1, the anode 20 is
(anode), a wasteful phenomenon occurs in which sputtered particles, ie, target atoms, etc. in the plasma generated in the space 7 are unilaterally attached and deposited on the anode 20.

Therefore, conventionally, under the above-mentioned phenomenon, the sputtered target atoms cannot be efficiently attached to the substrate 13 on the outside of the space 7, resulting in a decrease in the efficiency of the predetermined thin film production operation. This had the problem of causing

The present invention has been devised in view of the above-mentioned conventional problems, and its purpose is to prevent spatter generated in the space between both targets in order to prevent unreasonable sputtering from the backing plate, etc. Particles unilaterally adhere to the member provided on the back side of the target,
The purpose of this method is to improve the efficiency of forming a predetermined thin film by sputtering without causing wasteful phenomena such as absorption.

(Means for Solving the Problems) The present invention provides a cathode electrode instead of a conventional anode electrode.
This method is designed to solve the above-mentioned conventional problems by actively causing the sputtered particles that have been unilaterally attached to the electrode part to splatter and to use the sputtered particles for forming a thin film. It is something that

That is, the gist of the configuration of the present invention is that both targets and throat 4.
The intermediate electrode 6, which is provided facing the magnetic field space 7 from the rear side of 4a, is sputtered at a speed lower than the speed at which the sputtered particles of the spatial plasma generated in the space 7 adhere to the intermediate electrode 6. Both targets 4.
The point is that it is configured as a cathode with a lower voltage than 4a.

(Function) That is, in the sputtering apparatus characterized by the above configuration, some of the sputtered particles of the target 4.4a generated in the magnetic field space 7 by the sputtering of both targets 4.4a are transferred to the intermediate electrode 6. On the other hand, since the intermediate electric scraper 6 causes a sputtering phenomenon and re-sputters the sputtered particles attached to its surface, the sputtered particles are once again deposited into the space 7. This results in a high predetermined thin film formation rate.

Incidentally, since the sputter erosion rate of the surface of the intermediate electrode 60 is lower than the rate at which sputter particles adhere to the surface of the intermediate electrode 6 from the space 7 side, material components of the intermediate electrode 6 itself are sputtered and There is no such thing as being released inside.

Further, the secondary electrons emitted from the intermediate electrode 6 due to the sputtering phenomenon on the intermediate electrode 6 side move on the surface of the intermediate electrode 6 by EXB drift to promote ionization of the buffing gas. This also results in the effect that the plasma density within 7 becomes even higher.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

In Figure 1, 1.1a is a ring-shaped groove 2 between the two.
The figure shows a pair of backing plates made of copper or the like that are concentrically provided to form a backing plate, in which the central plate (1) is formed into a substantially cylindrical shape with a closed top, and the other plate (la) is shaped like a hollow disk. It is. 3.3a shows a cylindrical inner yoke and a ring-shaped outer yoke provided on each surface of the plate 1.1a.

4.4a shows a pair of targets made of ferromagnetic material or the like formed into circular ring shapes of different sizes, one inner target 4 fitted on the outer periphery of the inner yoke 3, and the other outer target 4a is fitted onto the inner peripheral side of the outer yoke 3a and attached to the surface of each backing plate 1, la. Reference numeral 7 designates a space formed between the sputtering surface 12 on the outer periphery of the inner target 4 and the sputtering surface 12a on the inner periphery of the outer target 4a. Sputter surface 12.
A magnetic field in a direction substantially perpendicular to 12a (for example, 2700e)
is formed. 11 is the backing brake) ISla
A variable voltage power source 15 for applying a voltage is connected to the yoke 11, with both targets 4.4a serving as cathodes.

Reference numeral 6 indicates an intermediate electrode which is located in the groove 2 between the backing brakes 11a and is attached via an insulator 14 with bolts or the like so that its upper end face faces the space 7. is connected to the power source 15 via voltage adjustment means 16 so that a negative voltage lower than the voltage applied to the target 4.4a is applied thereto.

5.5a is for each yoke 3 to cover the yoke 3.3a.
．． 3a shows the ground shield plate provided on the outside,
The shield plate 5.5a is grounded while being insulated from the yoke 3.3a, the backing plate Ia, etc. 1
0.10a indicates a cooling device separately provided below the backing plate l.

The present embodiment has the above configuration, and its usage and operation will be explained next. .

First, after setting the surrounding atmosphere of the apparatus to a low pressure atmosphere of sputtering gas such as argon, both targets 4.4a
If both targets 4.4a are sputtered by applying a voltage v7 to serve as a cathode, the target 4.4a will be sputtered in the magnetic field space 7 between both targets 4.48.
A plasma state is generated in which metal atoms, secondary electrons, argon gas ions, etc. are scattered.

Therefore, the sputtered target metal atoms in the plasma space are transferred to the substrate 13 provided above the space 7.
It reaches the surface and adheres uniformly to form a predetermined thin film. Further, at this time, a part of the target metal atoms and the like in the plasma space generated in the space 7 collide with the surface side of the intermediate electrode 6, causing a phenomenon in which they adhere and deposit.

On the other hand, a negative voltage v1 lower than both targets 4.4a is applied in advance to the intermediate electrode 6 to serve as a cathode. That is, for example, Vt = 600 volts, vt = 350 volts (set). Therefore, since magnetron discharge occurs also on the surface of the intermediate electrode 6, the spatter attached to the surface of the intermediate electrode 6 is The particles are sputtered again by the magnetron discharge and ejected again toward the space 7. That is, the metal atoms of the target 4.4a adhere to the surface of the intermediate electrode 6, and The attached metal atoms and the like are repeatedly sputtered and released into the space 7, thereby increasing the rate of thin film formation on the substrate 13.

Since the intermediate electrode 6 is in a state in which sputtering is suppressed more than the sputtering on the sputtering surface 12.12a of the target 4.4a, the adhesion speed of sputtered particles to the intermediate electrode 6 is higher than that due to sputtering. A situation in which the intermediate electrode 6 itself is sputtered due to a speed higher than the erosion rate is preferably avoided. Therefore, the material component of the intermediate electrode 6 is the same as that of the substrate 13.
There is no possibility that it will be contained in the thin film produced.

In addition, the secondary electrons emitted from the intermediate electrode 6 move on the intermediate electrode due to EXB drift and promote the ionization of the sputtering gas, that is, generate a magnetron discharge, causing plasma in the space 7. The density is further increased, and the thin film production rate can be further increased.

In the above embodiment, the applied voltage values of the target 4.4a and the intermediate electrode 6 were set to 600v and 350v, respectively, but the applied voltage values according to the present invention are not necessarily the same as those described above. However, it is not limited to this. According to the applicant's experiments, in the case of a target made of pure iron, a slight amount of iron was deposited on the surface of the intermediate electrode 6 when the voltage applied to the target was 500 V and the voltage applied to the intermediate electrode was 350 V. It was confirmed that the intended effects and effects of the present invention were achieved. In addition, in experiments using other setting values, the voltage applied to the intermediate electrode was approximately 150° lower than the target applied voltage.
Although good results were obtained when the value was as low as ~250 .mu., it was confirmed that these values were considerably influenced by the material of the target, the sputtering gas atmosphere, etc. Therefore, the present invention does not require specific numerical values.

In short, the intermediate electrode 6 is provided on the back side of the target 4.4a and at a position facing the magnetic field space 7, so that the sputtered particles of the spatial plasma generated in the space 7 are transferred to the intermediate electrode 6.
It is sufficient that the cathode is configured with a voltage lower than that of both targets 4.4a so that sputtering can be performed at a speed lower than that of the targets 4.4a.

Therefore, the specific means for attaching the intermediate electrode 6 is by no means limited to the above embodiments.

Furthermore, when applying voltages to both targets and the intermediate electrode, it is possible to simplify the configuration of the apparatus by using a single power supply as in the above embodiment, but the present invention naturally provides the advantage that the target and the intermediate electrode are connected to separate power supplies. It may be applied by

Further, the present invention is by no means limited to the specific configurations of other parts as in the above embodiments, and all of these can be freely modified within the intended scope of the present invention.

That is, it goes without saying that the arrangement of the magnets for generating a magnetic field in the space 7 may be as shown in the conventional arrangement shown in FIG. It may be formed into a rectangular ring shape as shown in FIG. However, in this case, it goes without saying that the shape of the intermediate electrode 6 must also be changed accordingly.

In addition, the inner yoke 3 located inside the inner target 4 is not an essential requirement of the present invention, but if the inner yoke 3 is made of the same material as the target 4, it is practical even if the ground shield plate 5 above it is removed. There is no problem above.

(Effects of the Invention) As described above, the present invention uses the intermediate electrode provided facing the magnetic field space formed between the sputtering surfaces of the inner target and the outer target as a cathode with a lower voltage than both targets. Since the structure is configured so that sputtered particles such as target atoms that are attached to the surface of the intermediate electrode from the space are re-sputtered at a speed lower than the deposition speed, the components of the intermediate electrode itself are sputtered by the sputtering of the intermediate electrode. It goes without saying that it is possible to appropriately prevent the release of gas into the space side, and maintain the quality of the produced thin film at a high level. The target atoms, etc. attached to the intermediate electrode can be used for thin film production by sputtering again, without causing waste such as unilateral adhesion and deposition of atoms, etc., and as a result, the predetermined thin film production speed can be increased compared to the conventional method. We have achieved the extraordinary effect of being able to perform this process fairly quickly and efficiently.

Moreover, the present invention can further increase the plasma density in the magnetic field space by the secondary electrons emitted by the sputtering on the intermediate electrode side, making it possible to perform sputtering under conditions of lower gas pressure and lower voltage. Furthermore, the present invention has the effect that the efficiency of thin film production work can be further improved.

[Brief explanation of drawings]

FIG. 1 is a schematic front sectional view showing an embodiment of a sputtering apparatus according to the present invention. FIG. 2 is a schematic plan view showing another embodiment. 3 and 4 show a conventional example, in which FIG. 3(A) is a schematic front sectional view of the main part, FIG. 3(B) is a schematic plan view, and FIG. 4 is a schematic front sectional view of the main part. 4...Inner target 4a...Outer target 6...Intermediate electrode 7...Magnetic field space 12.12a...Sputtering surface Applicant Osaka Vacuum Equipment Manufacturing Co., Ltd. Agent Patent attorney Noboru Fujimoto No. 11 !1 3rd i! 1 (a) (b)

Claims (1)

[Claims] A ring-shaped outer target 4a whose inner peripheral surface facing the sputtering surface 12 is a sputtering surface 12a is disposed around the outer circumference of the inner target 4 whose outer peripheral side surface is a sputtering surface 12, and both targets 4, 4a sputtering surface 12,
This is a sputtering apparatus in which a magnetic field space 7 is formed between the targets 4 and 12a in which spatial plasma is generated during sputtering of both targets 4 and 4a, and a position facing the space 7 on the back side of the targets 4 and 4a. is provided with an intermediate electrode 6, and the intermediate electrode 6 is connected to both targets so that sputter erosion is performed at a speed lower than the rate at which sputter particles of the spatial plasma generated in the space 7 adhere to the intermediate electrode 6. 4. A sputtering apparatus characterized in that the sputtering apparatus is configured as a cathode with a lower voltage than those of 4 and 4a.