JPH01142078A - Sputtering target - Google Patents

Abstract

PURPOSE:To enable the formation of a film having a narrow compsn. distribution and uniform characteristics by regulating the amts. of a rare earth metal, a transition metal and an intermetallic compd. of the metals in the compsn. of a target. CONSTITUTION:This sputtering target is based on a rare earth metal and a transition metal and is composed of rare earth metal grins, transition metal grains and grains of an intermetallic compd. of the metals. The intermetallic compd. is contained by <=20wt.% of the amt. of the target and the grain size of the compd. is 5-50% of the average grain size of the rare earth metal grains or the transition metal grains.

Description

[Detailed Description of the Invention] Industrial Field of Application The present invention is an optical disc that has rare earths and transition metals as its main components and is used in the production of rewritable magneto-optical discs that enable high-density, large-capacity recording. The invention relates to a sputtering target.

The conventional sputtering method utilizes a phenomenon in which particles constituting the target are released into space through an exchange of momentum when accelerated stationary ions collide with the surface of the target using the film material as a target. This is a technique in which particles released into space are deposited on a substrate to form a thin film. For magneto-optical disks that use rare earth/transition metal-based media as recording media, the sputtering method uses multiple targets depending on the number of component elements, such as a rare earth metal target and a transition metal target. There is a so-called multi-target method in which film formation is performed while adjusting discharge conditions such as discharge power, and a method in which a so-called alloy target is used in which two targets contain all the component elements. The multi-target method is often used at the research stage because it allows composition changes, but since electrodes are required depending on the number of targets, the alloy target method is the main method for mass production. Rare earth/transition metal alloy targets include targets that are made by mixing powders of pure metals as constituent elements and compression-pressed using a method such as HIP, or targets that are crushed after all the constituent metals have been melted. There are targets that are compressed and pressed using methods such as HIP.Alloy targets that are made by mixing pure metal powder and compression pressing do not contain intermetallic compounds, and are crushed after all of the component metals have been melted. Compression pressed type alloy target medium,
Compositionally possible intermetallic compounds are included, and components that are not compositionally intermetallic compounds exist as pure metals or alloys.

Problems to be Solved by the Invention However, in the above-mentioned conventional targets, metal elements or intermetallic compounds or two alloys are used.

When sputtering pure metal, there is a problem in that the particles are distributed in the direction in which they fly out, making it impossible to obtain uniform properties or composition on the substrate. The present invention has been made in view of the problem of peeling, and is intended to obtain a recording film with good uniformity of composition or characteristics on a substrate.

Means for Solving the Problems The present invention has been made to solve the above problems, and by adjusting the content of pure metal components and intermetallic compounds in the composition of the target, Moreover, a film with good uniformity of properties can be obtained.

Effect As mentioned above, by adjusting the content of pure metal components and intermetallic compounds in the composition of the target, particles flying out during sputtering can be reduced depending on the type or form of the component elements in the target. By utilizing the directional distribution, a film with uniform properties or composition can be formed on the substrate.

Embodiment FIG. 1 shows a structure diagram of a target in which intermetallic compounds and pure metals are present in appropriate amounts, which is an embodiment of the present invention.

For example, among rare earth/transition metal alloys, T b - Fe
, Co as an example, TbFe is placed around the transition metal particles.
Alternatively, an intermetallic compound of TbCo is formed. A target with such a structure can be produced by mixing pure metals as component elements and then compressing and pressing them using a method such as HIP, or applying energy such as heat after compression pressing to form intermetallic compounds. Form. The amount and particle size of intermetallic compounds are adjusted depending on the amount of energy. Alternatively, intermetallic compound powder such as T b Fe or T' b Co may be prepared in advance, mixed with pure metal powder, and compressed. For example, when Tb is present as a pure metal in the target, as shown in Figure 2a, it is relatively
When the substrate is located directly above the target because it flies out from the target at an angle, the concentration of Fe, Co and On the other hand, because they jump out directly above the target, the concentration is high in the center of the substrate and becomes low as it goes outside. In the case of magneto-optical media, this concentration difference appears as a distribution of coercive force. Base-5= If there is a composition distribution as described above on the plate, the coercive force will have a distribution as shown in FIG. 3, for example. The distribution in FIG. 3 is an example where the film composition is on the transition metal rich side on the substrate surface. However, for example, if Tb exists as an intermetallic compound in the target, during sputtering,
More of it will fly out directly above the target, and conversely, Fe and Co will come out at an angle. By taking advantage of this fact and adjusting the number of pure metal particles and intermetallic compound particles in the target component, it is possible to suppress the composition distribution on the substrate as shown in Figure 4. It becomes possible. For example, by mixing pure metals,
If an intermetallic compound is formed by applying heat after compression pressing, the thickness may be, for example, about 100 μm.

Effects of the Invention As mentioned above, by selecting the form in which each component element exists in the target, it is possible to form a film on the substrate with a small composition distribution and good uniformity of properties, which is useful for practical use. It is extremely effective.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of a target structure according to an embodiment of the present invention, Fig. 2a is a schematic diagram showing the flight direction distribution of Tb particles existing as pure metal flying out during sputtering, and Fig. A schematic diagram showing the flight direction distribution of Fe particles existing as metal flying out during sputtering. Figure 3 is a graph of the coercive force distribution on the substrate surface of a film formed using a target with an inappropriate content of intermetallic compounds. FIG. 4 is a graph of the distribution of coercive force on a substrate of a film formed with a target containing an appropriately adjusted intermetallic compound. 1...Fe particles, 2...Intermetallic compound, 3...Tb particles. Name of agent: Patent attorney Toshio Nakao and 1 other person 4.0
Translation note
Ward-hehazuka

Claims (3)

[Claims] (1) A sputtering target characterized by containing a rare earth metal and a transition metal as main components, and containing at least rare earth metal particles, transition metal particles, and intermetallic compound particles of a rare earth metal and a transition metal. (2) The sputtering target according to claim 1, wherein the mass or weight of the intermetallic compound is within 20% of the mass or weight of the sputtering target material. (3) Claim 1 or 2, characterized in that the thickness or particle size of the intermetallic compound is 5% or more and 50% or less of the average particle size of the rare earth metal particles or transition metal particles. sputtering target.