JPH083740A - Magnetic circuit for magnetron sputtering - Google Patents

Abstract

PURPOSE:To improve the efficiency of using a target and to improve the film thickness distribution of films by increasing the width of a bar-shaped magnet in the central part of a magnetic circuit disposed behind the target and the width of peripheral edge magnet part parallel therewith. CONSTITUTION:The peripheral edge magnets 16 consisting of the ferritic magnets 4, 6 varying in polarities are erected at the peripheral edges of a flat planar rectangular yoke 3 made of pure iron. The central part 13 consisting of the bar-shaped rare earth magnet 5 and ferritic magnet 7 varying in polarities is erected at the central part thereof. Further, an intermediate part ferrite magnet 8 is disposed. The magnetic circuit obtd. in such a manner is arranged on the rear surface of the flat planar target by which magnetron sputtering is executed. The width of the central part magnet 13 of the magnetic circuit for magnetron sputtering is made larger than the width of the outer magnets 11, 12. Further, the width in the bar-shaped part of the peripheral edge magnets 16 which are parallel therewith and have the same length is set larger than the width of the outer magnets 14, 15. As a result, the magnetic field intensity is intensified and the erosion of the target is made uniform.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic circuit for magnetron sputtering for improving the use efficiency of a target and the film thickness distribution of a film.

[0002]

2. Description of the Related Art A conventional magnetic circuit for magnetron sputtering is shown in FIGS. 5 and 6, in which a magnetic circuit 2 is arranged on the back surface of a flat rectangular target 1. A plate-shaped rectangular yoke 3 made of pure iron, which constitutes a part of the magnetic circuit 2, has a peripheral ferrite magnet 4 provided upright along the peripheral edge thereof. Therefore, the peripheral ferrite magnets 4 are arranged on the rectangular yoke 3 so as to form a ring-shaped rectangle. At the center of the rectangular yoke 3, a rod-shaped center rare earth magnet 5 is erected. Inside the peripheral ferrite magnet 2, a peripheral inner ferrite magnet 6 having different polarities is erected on the rectangular yoke 3. Outside the central rare earth magnet 5, a central outer ferrite magnet 7 having a different polarity is provided upright on the rectangular yoke 3 so as to surround it. An intermediate ferrite magnet 8 is erected in a ring-shaped rectangular shape on the rectangular yoke 3 between the peripheral inner ferrite magnet 6 and the central outer ferrite magnet 7.

The magnetic field distribution in the conventional magnetic circuit for magnetron sputtering is shown in FIG.
The horizontal axis is the distance from the center axis of the target 1, the vertical axis is the magnetic field strength, B1 is the curve showing the magnetic field strength perpendicular to the target 1, and B2 is the curve showing the magnetic field strength parallel to the target 1.

In such a conventional magnetic circuit for magnetron sputtering, high-density plasma is generated in the space near the surface of the target 1 due to the action of the magnetic field. In particular, the magnetic field strength B1 perpendicular to the target 1 is The density of the plasma increases in the region where 0, that is, the region a in FIG. Therefore, the ions in the plasma are scattered around the region a of the target 1.

In order to explain the erosion situation in the target 1, in the target 1 shown in FIG. 8, a straight line portion between the line BB ′ and the line CC ′, CC ′, is shown.
The line from the line to the end of the target 1 is separated from the corner.

The erosion depth at the straight portion of the target 1 becomes α as shown in FIG. 9, while the erosion depth at the corner portion of the target 1 becomes β as shown in FIG.

[0007]

In the conventional magnetic circuit for magnetron sputtering, the plasma density becomes high in the region where the magnetic field strength B1 perpendicular to the target 1 becomes 0 as described above, and the erosion is centered on that region. It will progress. However, even if the target 1 is the same, if the target 1 is divided into a straight part and a corner part, the erosion depth β at the corner part becomes larger than the erosion depth α at the straight part, and the target usage efficiency is increased. And the life of the target is shortened, and the film thickness distribution of the film formed on the substrate is also deteriorated.

An object of the present invention is to solve the problems of the prior art, improve the efficiency of use of the target, prolong the life of the target, and improve the film thickness distribution of the film formed on the substrate. A circuit is provided.

[0009]

In order to achieve the above object, the present invention provides a flat plate-shaped rectangular yoke and a flat plate-shaped rectangular yoke which is erected on the rectangular yoke so as to stand on the rectangular yoke. A peripheral magnet arranged in a ring-shaped rectangle, and a bar-shaped central magnet standing upright in the same direction as one side of the rectangular yoke at the central portion of the rectangular yoke are arranged behind the target, In a magnetron sputtering magnetic circuit that forms a racetrack-shaped magnetic field, the width of the rod-shaped central portion magnet is increased, and the rod-shaped central portion magnet that is parallel to the rod-shaped central portion magnet in the peripheral edge magnet is almost the same as the rod-shaped central portion magnet. The feature is that only the width of the portion of the same length is increased.

[0010]

In the present invention, the width of the bar-shaped central magnet and the width of the portion of the peripheral magnet that is approximately the same length as the bar-shaped central magnet parallel to the bar-shaped central magnet are increased. The magnetic field strength can be increased without changing the shape of the magnetic field distribution in the straight part of the target. Therefore, the difference in erosion depth between the straight line portion and the corner portion of the target is eliminated, and the film thickness distribution of the film formed on the substrate is improved.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. A magnetic circuit for magnetron sputtering according to an embodiment of the present invention is shown in FIGS. 1 and 2, and in these drawings, the magnetic circuit for magnetron sputtering 1
0 is disposed on the back surface of the flat rectangular target 1. A flat iron plate-shaped rectangular yoke 3 forming a part of the magnetron sputtering magnetic circuit 10 is provided with a peripheral ferrite magnet 4 standing along the peripheral edge thereof. Therefore, the peripheral ferrite magnets 4 are arranged on the rectangular yoke 3 so as to form a ring-shaped rectangle.
Inside the peripheral ferrite magnet 2, a peripheral inner ferrite magnet 6 having different polarities is erected on the rectangular yoke 3. At the center of the rectangular yoke 3, a rod-shaped center rare earth magnet 5 is erected. Central outer rare earth magnets 11 are provided on both sides of the rod-shaped central rare earth magnet 5. On the outer circumference of the central rare earth-based outer magnet 11, a central outer ferrite-based magnet 7 having different polarities is erected on the rectangular yoke 3 so as to surround it. On both sides of the central outer ferrite-based magnet 7, the central outer ferrite-based magnet 12 is provided.
Is provided. Therefore, the width of the central magnet 13 is increased by the central rare earth magnet 5, the central rare earth outer magnet 11, the central outer ferrite magnet 7, and the central ferrite outer magnet 12. Further, inside the peripheral edge inner ferrite-based magnet 6, a peripheral edge ferrite-based inner magnet 14 which is parallel to the rod-shaped central portion rare earth-based magnet 5 and has substantially the same length as this is provided.
On the outer side of the peripheral ferrite magnet 4, a peripheral ferrite outer magnet 15 is provided which is parallel to the rod-shaped central rare earth magnet 5 and has substantially the same length. Therefore, the peripheral edge magnet 16 includes the peripheral edge ferrite-based magnet 4, the peripheral edge inner ferrite-based magnet 6, the peripheral edge ferrite-based inner magnet 14, and the peripheral edge ferrite-based outer magnet 15 so that the width thereof is parallel to the central rare-earth magnet 5. And they are increased by the same length. An intermediate ferrite magnet 8 is erected in a ring-shaped rectangular shape on the rectangular yoke 3 between the peripheral inner ferrite magnet 6 and the central outer ferrite magnet 7.

The magnetic field distribution in such an embodiment is shown in FIG.
In the same figure, the broken line shows the magnetic field distribution of the example, and the solid line shows the magnetic field distribution of the conventional example. In the figure, the horizontal axis is the distance from the center axis of the target 1, the vertical axis is the magnetic field strength, B1 is a curve showing the magnetic field strength perpendicular to the target 1, and B2 is the magnetic field strength parallel to the target 1. It is a curve.

In such an embodiment, as in the conventional example, the ions in the plasma are sputtered around the region a of the target 1, but the width of the central magnet 13 and the peripheral magnets. Since the width of the portion having substantially the same length as the rod-shaped central magnet 13 parallel to the rod-shaped central magnet 13 in 16 is increased, the shape of the magnetic field distribution in the linear portion of the target 1 is not changed. The magnetic field strength can be increased. Therefore, the difference in erosion depth between the straight line portion and the corner portion of the target 1 is eliminated, and the film thickness distribution of the film formed on the substrate is improved.

As shown in FIG. 4, the target 1 has a straight line portion CC-C 'between the line BB' and the line CC '.
The area from the line to the end of the target 1 is separated from the corner.

By the way, in the above-described embodiment, the peripheral edge magnet behind the target corner portion may be shaved so as to be narrower than the width of the peripheral edge magnet behind the target linear portion, or the peripheral edge behind the target linear portion. The width of the peripheral magnet may be increased by making the longitudinal cross section of the partial magnet into a spindle shape. Further, the central magnet and the peripheral magnet may be electromagnets or permanent magnets.

[0016]

According to the present invention, the width of the bar-shaped central magnet,
Since the width of the portion of the peripheral magnet that is approximately the same length as the rod-shaped central magnet parallel to the rod-shaped central magnet is increased, the magnetic field strength can be changed without changing the shape of the magnetic field distribution in the linear portion of the target. Can be stronger. for that reason,
The difference in erosion depth between the straight line portion and the corner portion of the target is eliminated, and the film thickness distribution of the film formed on the substrate is improved.

[Brief description of drawings]

FIG. 1 is a plan view of an embodiment of the present invention.

FIG. 2 is a sectional view of an embodiment of the present invention.

FIG. 3 is a graph showing a magnetic field distribution in the example of the present invention.

FIG. 4 is an explanatory diagram of an embodiment of the present invention.

FIG. 5 is a plan view of a conventional magnetic circuit for magnetron sputtering.

FIG. 6 is a sectional view of a conventional magnetic circuit for magnetron sputtering.

FIG. 7 is a graph showing a magnetic field distribution in a conventional magnetic circuit for magnetron sputtering.

FIG. 8: Conventional magnetic circuit for magnetron sputtering

[Explanation of symbols]

 1 ・ ・ ・ ・ Target 3 ・ ・ ・ ・ ・ ・ Rectangular yoke 4 ・ ・ ・ ・ ・ ・ ・ Ferrite magnet on the periphery 5 ・ ・ ・ ・ Rare earth magnet on the center 6 ・ ・ ・・ ・ ・ Ferrite magnets on the periphery 7 ・ ・ ・ ・ ・ ・ ・ ・ Ferrite magnets on the center 8 ・ ・ ・ ・ ・ ・ ・ ・ Ferrite magnets on the middle 10 ・ ・ ・ Magnetic circuit for magnetron sputtering 11・ ・ ・ ・ ・ ・ ・ Center rare earth system outer magnet 12 ・ ・ ・ ・ ・ ・ Center center ferrite system outer magnet 13 ・ ・ ・ ・ ・ ・ Center center magnet 14 ・ ・ ・ ・ ・ ・ Peripheral part ferrite system Inner magnet 15 ・ ・ ・ ・ Ferrite outer magnet 16 ・ ・ ・

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[Procedure amendment]

[Submission date] March 28, 1995

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Brief description of the drawing

[Correction method] Change

[Correction content]

[Brief description of drawings]

FIG. 1 is a plan view of an embodiment of the present invention.

FIG. 2 is a sectional view of an embodiment of the present invention.

FIG. 3 is a graph showing a magnetic field distribution in the example of the present invention.

FIG. 4 is an explanatory diagram of an embodiment of the present invention.

FIG. 5 is a plan view of a conventional magnetic circuit for magnetron sputtering.

FIG. 6 is a sectional view of a conventional magnetic circuit for magnetron sputtering.

FIG. 7 is a graph showing a magnetic field distribution in a conventional magnetic circuit for magnetron sputtering.

FIG. 8: Magnetic circuit for conventional magnetron spatter

9 is a sectional view taken along the line A-A ′ in FIG.

FIG. 10 is a cross-sectional view of a corner portion (for example, above the line BB ′) of FIG.

[Explanation of Codes] 1 ... Target 3 ... Rectangular yoke 4 ... Perimeter ferrite magnet 5 ... Center Rare type magnet 6 ・ ・ ・ ・ ・ ・ Ferrite magnet on the periphery 7 ・ ・ ・ ・ ・ ・ Ferrite magnet on the center 8 ・ ・ ・ ・ ・ ・ Ferrite magnet on the middle 10 ・ ・ ・ ・ Magnetic circuit for magnetron sputtering 11 ・ ・ ・ ・ ・ ・ Center Rare earth system outer magnet 12 ・ ・ ・ ・ ・ ・ Center center ferrite system outer magnet 13 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Center Part magnet 14 ・ ・ ・ ・ Ferrite part ferrite inner magnet 15 ・ ・ ・ ・ Peripheral ferrite system outer magnet 16 ・ ・ ・ ・ ・ ・ ・ ・ Peripheral part magnet

Front page continued (72) Inventor Masasuke Sushiro, 2500 Hagien, Chigasaki City, Kanagawa, Japan Vacuum Technology Co., Ltd. Inventor Hidenori Suwa Inside 2500 Vacuum Hagizono, Chigasaki City, Kanagawa Japan Vacuum Technology Co., Ltd.

Claims (1)

[Claims] 1. A flat plate-shaped rectangular yoke, a peripheral edge magnet arranged in a ring-shaped rectangular shape on the rectangular yoke by standing upright along the peripheral part of the flat plate-shaped rectangular yoke, and a rectangular yoke. In the magnetic circuit for magnetron sputtering, a bar-shaped central magnet standing upright in the same direction as one side of the rectangular yoke is disposed behind the target in the central part of the magnetic circuit for magnetron sputtering. The width of the rod-shaped central portion magnet is increased, and only the width of a portion of the peripheral edge magnet that is substantially the same length as the rod-shaped central portion magnet parallel to the rod-shaped central portion magnet is increased. Magnetic circuit for magnetron sputtering.