JPS63195263A - Sputtering device - Google Patents

Abstract

PURPOSE:To successively obtain homogenous thin film, by fitting a means of regulating magnetic flux density in a discharge atmosphere on a target of a magnetic body so as to enable stable magnetron discharge at all times. CONSTITUTION:This sputtering device is composed essentially of a target 5 of a magnetic body, magnets 2 for causing magnetron discharge on the target 5, a yoke 1 for guiding magnetic flux generated from the magnets 2 and a means 6 of varying magnetic flux density. The means 6 is provided with driving units 7 for changing the relative distance between the magnets 2 and the target 5. Magnetic flux density BS1 in a discharge atmosphere on the target 5 is regulated by the means 6.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a sputtering apparatus that sputters a magnetic target using magnetron discharge to form a thin film on a sample.

[Conventional method] The magnetron method is a method in which electrons are trapped in mutually interlinked electric and magnetic fields to cause cycloidal motion, thereby inducing electrical discharge. In sputtering using this magnetron discharge, such an electric field and a magnetic field are formed on a target which is a discharge atmosphere, and the target side is set as a cathode, and the positive ions generated by the discharge are attracted to the target. It sputters target molecules. This method is characterized in that a magnet is placed below the target, and the target may be made of a magnetic material with high magnetic permeability.

[Problems to be Solved by the Invention] By the way, the magnetic flux emitted from the magnet is divided into one that penetrates the magnetic target and reaches the discharge atmosphere, and one that connects a magnetic path within the target. However, the saturation amount of the magnetic flux connecting the magnetic path within the target changes depending on the material and shape of the target, and gradually decreases as the target material becomes thinner after long-term use. As a result, the amount of magnetic flux reaching the discharge atmosphere increases accordingly, and the state of magnetron discharge changes, making it impossible to obtain the same thickness and physical properties of the produced thin film.

In view of the above-mentioned problems, the present invention maintains the magnetic flux density on the target at a constant level by adding a hardware function that can correct changes in magnetic flux due to consumption of the target during long-term use of the sputtering apparatus. The purpose is to realize a magnetron-type sputtering device that does not affect the thickness or physical properties of the thin film being created.

[Means for Solving the Problems] In order to achieve the above object, the present invention employs the following means.

That is, the sputtering apparatus according to the present invention includes a magnetic target, a magnet for causing magnetron discharge on the target, a yoke for guiding magnetic flux generated from the magnet, and a magnetic flux density in the discharge atmosphere above the target. It is characterized by comprising a magnetic flux density variable means for adjusting the magnitude of the magnetic flux density.

In addition, as a magnetic flux density variable means, there is particularly a means for adjusting the amount of magnetic flux reaching the discharge atmosphere by changing the magnetic resistance by changing the gap in the magnetic path, or by letting the magnetic flux escape midway. suitable.

[Function] With such means, even if the magnetic flux density of the discharge atmosphere changes due to long-term use of the sputtering device, the amount of magnetic flux reached can be changed by the magnetic flux density variable means, so the amount of change can be canceled out. becomes possible. This makes it possible to always induce a stable magnetron discharge regardless of the cross-sectional shape of the target material used or its consumption, and it is possible to repeatedly and continuously form homogeneous thin films on the specimens placed opposite each other. It is what it is.

[Example] Hereinafter, an example in which the sputtering apparatus of the present invention is constructed as a parallel plate type will be described with reference to the drawings.

(First Embodiment) In this embodiment, as shown in FIG. 1, a plurality of permanent magnets 2 are arranged symmetrically on a yoke 1, and these magnets 2 and the yoke 1 are connected to a housing 3. surrounded by. A backing plate 4 is loaded between the upper ends 3a of the side walls of the housing 3, and a magnetic target 5 is set on the backing plate 4.

On the other hand, the magnetic flux variable means 6 of this embodiment includes a drive device 7 that can change the relative distance between the magnet 2 and the target 5 to change the gap between them. This drive device 7
is equipped with an arm 7a that protrudes and retracts when driven by a motor, actuator, etc. (not shown), and this arm 7a
is attached to the bottom part 1a of the yoke 1 by passing through the bottom plate 3b of the housing 3 via a guide 7b, and the yoke 1
At the same time, the magnet 2 can be raised and lowered relative to the target 5 as shown by arrow I.

In the above, the relationship between the magnetic flux density Bm of the magnetic flux emitted from the magnet, the magnetic flux density Bs of the magnetic flux that penetrates the target 5 and forms a toroidal magnetic field in the discharge atmosphere, and the magnetic flux density Bt of the magnetic flux that passes through the target 5 is as follows: Regardless of , Bm −Bt+ Bs= (1) holds true. Now target 5 is consumed and Bt and Bs are Bt+ (Bt>Bh) and Bs respectively
If it becomes 1 (Bs+ >Bs), then Bm=
Bt+ +Bs+ ・-(2) holds, so from equations (1) and (2), Bs and Bs,
The relationship between Bsl = Bs+ (Bt Bt+) is obtained.

On the other hand, as shown in FIG. 4, the magnetic flux density tends to decrease as it moves away from the magnet. Using this property, the drive device 7 is operated to increase the magnetic flux density Bs of the magnetic flux reaching the discharge atmosphere.

By lowering the magnet 2 relative to the target 5 and increasing the magnetic resistance of the gap until (Bt Bt+ ) decreases, the increase in magnetic flux density can be canceled out.

It goes without saying that even if the magnet 2 is fixed and the target 5 is moved up and down, the same effects as in this embodiment can be obtained.

(Second Embodiment) As shown in FIG. 2, this embodiment has generally the same structure as the first embodiment, and common parts are designated by the same reference numerals.

In this embodiment, the yoke 1 is placed directly on the bottom plate 3b of the housing 3, and the magnetic flux density variable means 6 is provided with a thin shorting plate 8 as a magnetic flux shorting member capable of shorting the magnetic flux. This shorting plate 8 is arranged between the magnet 2 and the backing plate 4 by a mounting member (not shown).

In this embodiment, if the shorting plate 8 is used to saturate with a magnetic flux Bp equal to the increase in magnetic flux density (Bt Bt+) due to consumption of the target 5, the increase in magnetic flux density in the discharge atmosphere can be canceled out. can. Note that this shorting plate 8 may be added according to changes in magnetic flux density.

(Third Embodiment) As shown in FIG. 3, this embodiment has a generally similar configuration to both of the embodiments described above, and common parts are indicated by the same reference numerals.

In this embodiment, the magnet 2 is placed on a thin plate-shaped mounting plate 9, and the yoke 1 is located below the mounting plate 9 and is moved up and down relative to the magnet 2 by a drive device 7.

Since the magnetic circuit is closed, when the relative distance between the yoke 1 and the magnet 2 increases and the magnetic resistance in the gap between them increases, the magnetic flux exiting from the magnet 2 to the target 5 side decreases. Utilizing this property, by increasing the magnetic resistance of the gap by the increase in magnetic flux density (Bt Btl) due to consumption of the target 5, the increase in magnetic flux density in the discharge atmosphere can be canceled out.

Note that the present invention can of course be applied to structures other than the parallel plate type target structure used in the above-described embodiments. In addition, a magnetic flux detection sensor is attached to the target,
By amplifying the error from the target value and feeding it back to the magnetic flux variable means, real-time correction of the magnetic flux becomes possible.

[Effects of the Invention] By providing the magnetic flux variable means as described above, the present invention can always induce stable magnetron discharge regardless of the cross-sectional shape of the target or its consumption, and can form a thin film with uniform quality. It is possible to provide a sputtering device that can be manufactured repeatedly.

[Brief explanation of the drawing]

1 to 3 are schematic sectional views showing first to third embodiments of the present invention, respectively, and FIG. 4 is an explanatory view of the operation. 1... Yoke 2... Magnet 5... Magnetic target 6... Magnetic flux variable means 7... Drive device

Claims (4)

[Claims] (1) A magnetic target, a magnet for causing magnetron discharge on the target, a yoke for guiding the magnetic flux generated from the magnet, and for adjusting the magnitude of magnetic flux density in the discharge atmosphere above the target. 1. A sputtering apparatus comprising: magnetic flux density variable means. (2) The sputtering apparatus according to claim 1, wherein the magnetic flux density variable means includes a drive device capable of changing the relative distance between the magnet and the target. (3) The sputtering apparatus according to claim 1, wherein the magnetic flux density variable means includes a magnetic flux short-circuiting member capable of short-circuiting part of the magnetic flux between the magnet and the target. (4) The sputtering apparatus according to claim 1, wherein the magnetic flux density variable means includes a drive device capable of changing the relative distance between the magnet and the yoke.