JPS584914A - Sputter target for forming magnetic thin film with oxide - Google Patents

Abstract

PURPOSE:To effectively provide uniform and stable oxide magnetic thin film on the entire surface of a substrate by using, as a sputter target for the magnetic recording medium, Fe3O4 sinter obtained by containing a 0.5-10wt% of Cu and/or a 0.5-5wt% of Co each as an oxide in metal iron. CONSTITUTION:Using a magnetic oxide comprising Fe3O4 sinter obtained by containing in metal iron a 0.5-10wt% of Cu and/or a 0.5-5wt% of Co each as an oxide, a magnetic recording medium such as a magnetic disk is produced as follows : Poweders of Fe3O4, Co2O3 and CuO are sufficiently mixed at the specified weight ratio and grained into uniform particles into which some binders are mixed. They are then pressed into the specified shape, and heat treated for several hours at 1,250-1,300 deg.C in the inert gas environment. The treatment temperature necessary for changing to gamma-Fe2O3 is lowered and thus a load on the substrate is relieved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for forming a thin oxide magnetic thin film used as a magnetic recording medium in a magnetic disk drive, etc.
Regarding the target.

Improving the secrecy of records in magnetic recording devices is a constant trend in this field.In order to prevent this from happening, it is essential to make the record media thinner and thinner. As such, continuous thin film media that can be easily thinned, especially oxidized and amphoteric thin films, are attracting attention. The reasons for this are (1) low residual magnetic flux density, (2) high mechanical strength and chemical stability, and no protective film required for metal thin films. The advantage is that the space between media can be made smaller, making it suitable for high density and low cost.

Iron oxide thin films are used exclusively as oxide magnetic thin films because they are easy to form, and there are various methods for manufacturing them, but by sputtering using magnetide (Th5Ck) as a target, it is possible to make remagnetide as the main component. A simple and highly reproducible method for forming a ferromagnetic iron oxide thin film directly on a substrate has been proposed (Japanese Unexamined Patent Application Publication No. 1986-1999).
(See Japanese Patent Application No. 8200) b In this method, if cobalt is used as an additive to control the magnetic properties, the coercive force of the sputtered magnetite film can be arbitrarily controlled. The formed film was then subjected to R treatment (peaQn 2s et al. r-p6) using relatively expensive equipment to improve magnetic properties and stabilize the film.
2Ua processing) is performed. Normally, an alumite-coated alumite alloy substrate is used as a substrate, but when this type of substrate is exposed to high temperatures, the surface plane layer may be damaged, or the coated alumite layer may become invisible to the base aluminum alloy. Since problems such as cracks occur due to the difference in the coefficient of thermal expansion, it is preferable that the γ ratio treatment temperature be as low as possible. However, for the macnetite film formed by the above method, it is difficult to lower the γ ratio treatment temperature to a temperature that does not impose a burden on the substrate, and in particular, the macnetite film to which cobalt is added tends to have a further γ ratio treatment temperature.

As a method to solve this problem, the present inventors first focused on magnetite, which is formed directly on a substrate by sputtering in a neutral gas or a mixture of a neutral gas and an oxidizing gas using magnetite as a target. The oxidized q# magnetic thin film as a component is characterized by containing copper as an additive, and in order to control the magnetic properties, an oxide@magnetic thin film may also be used that further contains cobalt as an additive. proposed.

The present invention provides a sputter target for forming a magnetic oxide thin film suitable for use in the above invention, and the sputter target for forming a magnetic oxide thin film according to the present invention can be manufactured, for example, by the following method. be able to. k”e 304 of the predetermined gravity ratio, Go 2-
After the powders of 03 and CuO are sufficiently mixed and pulverized to have a uniform particle size, a binder is mixed therein and press-molded into a predetermined shape. This molded body is subjected to a controlled heating and cooling process in an inert gas atmosphere to a maximum temperature of 1.250 to 1,300
By performing heat treatment at ℃ for several hours, a crack-free and robust Ct+, Cu-added Fe 304 sintered body can be obtained.

The merits of the present invention will be explained in detail with reference to Examples below.

Example 1゜The metal iron ratio was 1. Q, 4.
0.

l+'eaQ4 containing 6.0 wt- Cu as oxide
Prepare sintered bodies and use them as targets at an arcon pressure (PAr) of 8 x 10-” Torr,
) M plate id distance Ill D = 30wa, adhesion speed (
8.R) 1. On an A1 alloy substrate which was subjected to R, F spacing and taring at 250 A/min and anodized with anodized nuclide.
Fe+0 containing Cu of 5, 4.0, 6.0 tqb
Four films were formed. When these films were subjected to oxidation treatment for 1 hour in the air, it was confirmed that all the films were converted into γ-'e 203 films by the oxidation treatment at 250 to 275°C. On the other hand, as a comparative example, a k"e304 film formed under the same conditions using a pure Fe5O4 sintered body without adding eu as a target required an aggregation treatment at 320 DEG C. or higher in order to form an r-FezOa film.

Furthermore, in the case of Cu-added Rue203 film, pure γ-Fe 20
There was a decrease in Hc compared to the 3 films, but this was more pronounced as the amount of Cu added increased (see table).

Example 2゜By the same manufacturing method, metal iron ratio -2.0 to 3.0 weight (1) Co, 2.2 to 4.4 weight'klk% 0)
A Feast sintered body containing Cu as an oxide was prepared and used as a target in an argon atmosphere at Phr = 2.
X 10-3~5 X 10-”Torr, D =
30m, 8, Roux 1.200A/1nin (1
1,500 particles were deposited on an aluminum alloy substrate coated with alumite in the same manner as in Example 1 using the magnetron sputtering method under the following conditions.
~1.70OA thick with various compositions of Co, Cu-containing F
An eaO4 film was formed. These membranes are 250-300'
Co, Cu association γ can be easily formed by in-air oxidation treatment with C.
It was possible to convert it to FezO3 film. Furthermore, their magnetic properties are B
s3ρOOU.

80.7. S (coercive force rectangularity) 0.8. Hc500-8
000e, which was inferior to density recording media (
(See table) 0 Simultaneously adding Co and Cu in this manner had the advantage of increasing Hc and promoting rFezos formation.

Example 3 By the same manufacturing method as above, 4°0 to 5.01 (i% Co
.

pe containing 5 to 7.5 times IkLlb of Cu as oxide
304 sintered bodies and used them as targets.
ar = 6 x 10-'~8 x 10-''Torr
, D = 130m.

S, 几=100-1000A/mtn (7) In the case of 9, a Co, Cu alloy 1'6sQ4 film was formed on the same substrate as before. These films were oxidized in air at 275-300°C. by Hc90G-1,3000e
A high coercive force medium was obtained (see table).

Using the target and sputtering conditions shown in Example 2, Co and Cu-containing Fe 304 mf were formed on an aluminum alloy disk substrate made of alumite T6 with an outer diameter of 210 m, and this was oxidized to form a Go and Cu-containing -Fe2es film. I made a prototype disk. This disk was installed in a disk 1%V tester, and the track size was 20 μm, the recording hardness was 24,
00 (Nyu output in JFRPl/,!: When we measured it, we confirmed that there was a sloped playback output in the circumferential direction over the entire surface of the disc. It is a direct injection thin powder used for magnetic disk media etc. using a sputter target for thin cedar formation, and has a lower R-'E2G3 processing temperature than that of Binmai, which reduces the burden on the substrate. It becomes possible to efficiently form an oxide amphoteric thin film having a wide range of low-temperature properties over the entire surface of the substrate.

゛h

Claims (1)

[Claims] Sputtering for forming a magnetic oxide thin film consisting of a Fe30a sintered body containing Co as an oxide in an amount of 0.5 to 10 percent Co or further 0.5 to 5 percent Co based on metal iron. target.