JPH06264218A - Sputtering target - Google Patents

Abstract

PURPOSE:To provide a sputtering target capable of sputtering by supply of high electric power even under conditions simultaneously satisfying low pressure of sputtering gas and low voltage and capable of forming a high quality coating film, a magnetic recording medium, etc., at a high speed. CONSTITUTION:A ferromagnetic body having a circularly grooved structure 4 in the surface is laminated on a backing plate 2 and a magnet 3 is disposed behind the baking plate 2 to obtain the objective sputtering target 1 disposed opposite to a substrate on which a film is formed. A magnetic field from the magnet 3 is leaked, plasma density is increased and high-speed sputtering of the ferromagnetic body is enabled.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sputtering target which is arranged so as to face a substrate to be subjected to a film-forming process and which is used when a ferromagnetic material such as Fe, Co or the like is formed by high speed sputtering. is there.

2. Description of the Related Art Sputtering is one of the techniques for forming a metal coating on the surface of a substrate. In recent years, there is an increasing demand for forming magnetic thin films by sputtering various ferromagnetic materials. As shown in FIG. 1, the conventional sputtering apparatus has a backing plate 2 supporting a target material 1 provided on a magnetic field generator 3. In this apparatus, when the target material 1 is a ferromagnetic material having a high magnetic permeability such as Fe, the magnetic flux of the magnetic field generator 3 is shielded by the ferromagnetic target material 1 and plasma discharge does not occur. Therefore, the thickness of the target material 1 is 3 m
Although it was necessary to form it as thin as about m, a high voltage was still required because the leakage magnetic flux appearing on the surface of the target material 1 was small. Furthermore, the discharge voltage-current characteristics greatly change in the initial and final stages of the target, and for example, the voltage fluctuates even when the power is constant, and it is difficult to form a reproducible film. In addition, there is a problem that when the sputtering gas pressure is increased and high power is applied to form a film for high-speed production, the shadowing effect is largely exerted by the sputtering gas and the crystallinity is deteriorated. Further, in the sputtering film formation using the conventional planar magnetron type sputtering target, for example, Fe- which is a soft magnetic material is used.
When the Si material is formed into a film, high power cannot be applied at a low sputter gas pressure capable of forming a dense film having excellent crystallinity during film formation, and when high power is applied at a high sputter gas pressure. The coercive force increased and the characteristics of the soft magnetic material were lost. The gap type target developed to solve these problems was expensive and uneconomical to form a gap.

The present invention has been made in order to solve the above problems, and it is possible to perform sputtering with a large power input even under the condition that a low sputtering gas pressure and a low voltage are simultaneously satisfied. The present invention provides a sputtering target capable of producing a high-quality coating film or a magnetic recording medium at a high speed and used by simply improving a conventional planar sputtering apparatus.

That is, the present invention relates to a sputtering target formed by laminating a ferromagnetic material having an annular groove structure on its surface on a backing plate. The present invention will be described with reference to FIG. 3. The ferromagnetic material 1 is plate-shaped and has an annular groove structure 4 formed on the surface. With this structure, the magnetic field of the magnetic field generator 3 leaks to the surface of the ferromagnetic sputtering target.
The annular groove structure 4 may have a circular shape, a rectangular shape, or another shape. The depth of the depression is preferably 30 to 90% of the thickness of the ferromagnetic material. As the ferromagnetic material, one having a relative magnetic permeability of 1 to 10,000,000 can be used.
Ni, Co, Fe and compounds containing these as the main components can be used. The backing plate 2 is for supporting the ferromagnetic material 1. The backing plate 2 is C
It is made of u or the like and is bonded to the ferromagnetic material 1. The permanent magnet 3 is provided on the back surface of the backing plate 2 and transmits a magnetic field to the hollow structure of the ferromagnetic material 1. The sputtering target of the present invention is used for forming a thin film of a ferromagnetic material sputtered on the surface of a base material (not shown) arranged to face each other. The sputtering conditions are sputtering gas pressure of 0.1 to 100 mT.
Orr and voltage of 200 to 1 KV are preferable.

EXAMPLE A backing plate and a Fe sputtering target material bonded as a ferromagnetic material having a structure shown in FIG. 2 (size 100 mm × 200 mm, maximum thickness 5 m).
When the magnetic field leaked onto the target was measured using m, the thickness of the bottom of the depression was 2 mm), it was 8000 Oe (see FIG. 4). Next, using this sputtering target, discharge voltage-current characteristics at a sputtering gas pressure of 2 mTorr were measured and shown in FIG. It was confirmed that magnetron discharge occurred near 300 to 400 V and a high current could be applied. On the other hand, the leakage magnetic field on the surface of a conventional sputtering target made of Fe (size 100 mm × 200 mm) for planar magnetron sputtering was measured and found to be 20 Oe (see FIG. 6). The discharge voltage-current characteristic diagram of this sputtering target is shown in FIG. This sputtering target has a low sputtering gas pressure (2 mTorr) of 750 at the beginning of use.
It has been found that a film having a high deposition rate cannot be formed because the electric power can be applied only to about 200 W even when an applied voltage as high as V is applied.

The following effects have been confirmed by the present invention. (1) It becomes possible to form a fairly strong magnetic field on the target surface, and as a result, the discharge impedance can be reduced, and the sputtering target generates less heat and improves the power (contribution to sputtering) efficiency. (2) Since the discharge plasma is strongly generated only in the voids of the sputtering target due to the devise of the magnetic circuit, the electron impact on the substrate is extremely small and the substrate is not heated during sputtering. (3) Even if high power is applied for the purpose of high-speed film deposition, the voltage is low, so that the sputtering target does not reach high temperature, high-temperature low-temperature sputtering is promoted, and power loss is small. (4) Since high power can be applied even with a low sputtering gas pressure, a dense and crystallized film can be formed even when deposited at a high speed.

[Brief description of drawings]

FIG. 1 is a sectional view of a conventional sputtering target.

FIG. 2 is a perspective view of a sputtering target of the present invention.

3 is a sectional view taken along the line AA ′ in FIG.

FIG. 4 is a graph showing leakage magnetic field strength.

FIG. 5: Discharge characteristic diagram

FIG. 6 is a graph showing leakage magnetic field strength.

[Explanation of symbols]

 1 target material 2 backing plate 3 permanent magnet 4 groove structure

Claims (1)

[Claims] 1. A sputtering target obtained by laminating a ferromagnetic material having an annular groove structure on the surface of a backing plate.