JPH02236276A - Magnetic target for magnetron sputtering and its manufacturing method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a target suitable for use in producing a magnetic thin film by magnetron sputtering and a method for producing the same.

[Conventional technology The comagnetron sputtering method uses a magnet placed on one side of the target to generate a leakage magnetic field on the other side of the target, and causes many ions created by the leakage magnetic field to collide with the target. This method produces thin films at a high deposition rate on a substrate near a target, and its use has been rapidly increasing in recent years.

On the other hand, using this magnetron sputtering method, magneto-optical recording medium thin films such as TbFeCo, CoNi, etc.
When producing a magnetic thin film such as a magnetic recording medium thin film made of CoCr or the like, there is a problem in that the sputtering efficiency and target utilization efficiency are poor due to the weak leakage magnetic field.

In order to solve these problems, a strong magnet such as a rare earth magnet has conventionally been used as the magnet disposed on one side of the target.

[Problems to be Solved by the Invention] However, even with such a method, a sufficiently strong leakage magnetic field cannot be obtained.

Therefore, in view of the above circumstances, an object of the present invention is to provide a target that generates as strong a leakage magnetic field as possible and has good sputtering efficiency and target utilization efficiency, and a method for manufacturing the same.

[A Thousand Steps to Solve the Problems] In order to achieve the above object, the present invention provides a magnetic target for magnetron sputtering having easy magnetization anisotropy.

Another aspect of the present invention is a method for manufacturing a magnetic target for magnetron sputtering, characterized in that in a method of press-forming and sintering raw material powder, the press-forming is performed while applying a magnetic field.

In this manufacturing method, if the direction in which the magnetic field is applied is the pressing direction, the device to be used becomes simple.

[Function] In the magnetic target for magnetron sputtering of the present invention, the direction of easy magnetization may or may not be parallel to the target surface. The locations in the target that have an easy magnetization direction, that is, the locations that have easy magnetization anisotropy, may be distributed uniformly throughout the target, but are mainly distributed in the erosion areas where sputtering progresses and wears out. You can leave it there.

The components, composition, shape, etc. of the target may be those commonly used and are not particularly limited.

If the magnetron sputtering method is performed using such a target, a sufficiently strong leakage magnetic field can be obtained. This means that the generated magnetic flux does not close its loop inside the target as it does when using traditional targetfts.
It is presumed that this is because it leaks to the other side of the target.

Next, in the method for manufacturing a magnetic target for magnetron sputtering, which is another aspect of the present invention, the raw material powder is pressure-molded while applying a magnetic field.

The direction in which this magnetic field is applied becomes the easy magnetization direction of the obtained target. Since the magnetic field can be applied in any direction, the direction of easy magnetization necessary to achieve the object of the present invention can be easily determined.

[Example] The present invention will be further explained below with reference to Examples and Comparative Examples.

Examples 1-3 Tb-Fe. Tb-Fe-Co and Gd-Tb
- For the purpose of manufacturing Fe alloy targets, Tb40t powder (average grain size 3 μm corner or less), each having a purity of 99.9% by weight or more, Gd. 03 powder (average particle size 3pm or less), Fe powder (particle size 200 mesh (Tyler,
The same applies hereafter), Co powder (particle size 200 mesh or less), metallic Ca (particle size 4 mesh or less), and anhydrous C
aCj! , (particle size of 100 mesh or less) were blended in the amounts shown in Table 1 and thoroughly mixed.

The mixture was placed in a stainless steel reaction vessel, heated to 1000° C. in about 1 hour in a stream of high-purity Ar gas, maintained at that temperature for 5 hours, and then cooled to room temperature. The resulting lumpy mixture was poured into 5 liters of water. After the lumpy mixture disintegrates, the upper layer of Ca (OH
) The suspension was separated by decantation. The alloy powder obtained by repeating this operation was brought into contact with dilute acetic acid of pH 4.5, and then washed with water and ethanol.
Vacuum drying was performed at 0° C. and IXIO-2 Torr.

Next, each of these alloy powders (average particle size 60 μm)
g was charged into a graphite molding machine with an inner diameter of 100 mm, and was heated to
A pressure of 50 kg/cd was applied.

Furthermore, the degree of vacuum was set to 5 x 10-' Torr, and the temperature was raised to 1000 °C while applying pressure. After the temperature was raised, the pressure was set to 250 kg/1, and after maintaining that temperature for 1 hour, it was cooled to room temperature. did.

The composition of the obtained sintered body (diameter 100 fi, thickness 4.5 fl) was as shown in Table 2. Then, we cut out a part (10 fl square) of these sintered bodies and measured the initial magnetization permeability in the pressing direction and the direction perpendicular to it using a sample vibrating magnetometer. was 4.0, and the direction perpendicular to it was 2.5. Therefore, it was found that all the sintered bodies had an easy magnetization direction in the pressing direction.

Next, using these sintered bodies, magnetron sputtering method (Ar gas pressure: 5
A thin film (film thickness: 3000 mm) was produced on a soda glass substrate using a discharge power of 500 W).

After producing the thin film, the magnetic flux density ratio on the target surface, sputtering efficiency, and changes in film composition over time were measured in each test. These measurement methods are as follows. Magnetic flux density ratio on target surface: Subata time is 5 and 6
The ratio of the maximum magnetic flux density on the target surface obtained after 0 hours has passed is measured.

Sputtering efficiency: Measure the film formation rate after 5 hours of sputtering time has elapsed.

Change in film composition over time: The variation (range) of the total amount of rare earth elements in the thin film obtained at the time of 5, 20, 40 and 60 hours of Subata time is determined.

Comparative Example 1 A test was conducted in the same manner as in Example 1 except that no magnetic field was applied during molding under a pressure of 50 kg/cd. The measurement results of the initial magnetic permeability were 3.0 in all directions.

Table 2 shows the results obtained in the above examples and comparative examples. [Effects of the Invention] As is clear from the above, the present invention provides a target suitable for magnetron sputtering, which has little change in magnetic flux density on the target surface or change in film composition over time, and has high sputtering efficiency. I can do it.

Furthermore, if the magnetic target of the present invention is used, the plasma confinement effect will be sufficient near the surface of the target, so impurity ions and electrons present in the device will be efficiently captured and will no longer float. It is also possible to improve the film quality of the obtained thin film.

Patent applicant Sumitomo Metal Mining Co., Ltd.

Claims (1)

[Claims] 1. A magnetic target for magnetron sputtering having easy magnetization anisotropy. 2. A method for producing a magnetic target for magnetron sputtering, in which raw material powder is press-molded and sintered, the press-forming being performed while applying a magnetic field. 3. The method for manufacturing a magnetic target for magnetron sputtering according to claim 2, wherein the direction in which the magnetic field is applied is the pressing direction.