JPH01240653A - Sputtering cathode - Google Patents

Abstract

PURPOSE:To increase the radius of curvature of the electron capturing regions on both end parts of a magnet to facilitate spreading around of electrons by forming the magnet of a bar-shaped magnet and enclosing magnet and specifying the shape of the enclosing magnet. CONSTITUTION:The sputtering cathode of a planar magnetron sputtering device is formed by providing the magnet consisting of the improved bar-shaped magnet 4B which is rectangular in the central part and has the rectangular shape wider than the width of the rectangular shape of the central part at both end parts and the enclosing magnet 4A to the rear face of a backing plate. The longest width on the inner side at both ends in the longitudinal direction of the magnet 4A is made wider than the longest width on the inner side of the central part. The longitudinal length in the central part of the magnet 4A is made shorter at both ends by as much as the space width than that of the magnet 4B and wider by as much as the space width in said part. The film thickness distribution of a substrate is improved and stable discharge is executed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to the shape of a magnet used in a Brenner magnetron sowing device for forming thin films in a vacuum chamber.

(Prior art) Sputtering is performed using argon cations Ar in a vacuum.
This is a method of forming a thin film by accelerating ``in an electric field, colliding it with a negatively charged target, knocking out the atoms of the target, and depositing the atoms on the target substrate.''

The conventional planar magnetron sputtering equipment is
As shown in the figure. A target 3 is metal bonded to the surface of a rectangular, table-shaped puffing plate 1.
On the back side of backing plate 1 is a buffing plate l.
water channel 7 for cooling and backing plate 1
There is a magnet 9 attached to a yoke 8 of the same size. The magnet 9 consists of a mouth-shaped magnet 9A (hereinafter referred to as a mouth-shaped magnet) located around the yoke 8 and a rod-shaped magnet 9B (hereinafter referred to as a rod-shaped magnet) arranged approximately in the center of the mouth-shaped magnet 9A. The rod-shaped magnet has a rectangular central portion and a rectangular shape with both end portions wider than the rectangular width of the central portion. The mouth-shaped magnet 9A and the rod-shaped magnet 9B are arranged so that their long sides are in the longitudinal direction (meaning the direction perpendicular to the direction of movement of the substrate 5, the same applies hereinafter). The face of the mouth-shaped magnet 9A on the target 3 side is the S pole, and the rod-shaped magnet 9B
The surface on the target 3 side is the north pole.

The magnet 9 is used to generate a magnetic field on the surface of the target 3, and this magnetic field captures the electrons being discharged during sputtering and causes magnetron movement.
Ionization of Ar atoms is promoted by colliding with r atoms.

FIG. 3 is a perspective view of the magnet 9 portion.

As shown in FIG. 2, the substrate 5 moves parallel to the surface of the target 3 at a constant speed (-mark).

When it enters the film forming area defined by the opening of the adhesion prevention plate 6, the formation of the thin film 10 begins, the thin film 10 grows while it passes through, and the formation of the thin film 10 ends when it finishes passing through.

(Problems to be Solved by the Invention) The conventional pre-nurse battering cathode has the following problems because the magnet arranged on the back surface of the backing plate 1 consists of a mouth-shaped magnet 9A and a rod-shaped magnet 9B. .

(1) The film thickness 10 of the substrate portion passing over both ends in the longitudinal direction of the target 3 is thinner than the film thickness 10 of the substrate portion passing over the central portion, resulting in poor film thickness distribution.

(2) In order to increase the deposition rate for a film thickness of 10, it is necessary to narrow the width of the opening (referring to the length in the direction of substrate movement; the same applies hereinafter), but in this case, the utilization efficiency of target 3 will decrease. Therefore, the width of target 3 must also be narrowed.

Therefore, it is necessary to make the width of magnet 9 narrower,
In this case, the magnetic field strength on the surface of the target 3 will not be strong enough to capture electrons, and the discharge will become unstable.

(Means for Solving the Problems) The present invention provides a planar magnetron bafta rig device in which a magnet is provided on the back surface of a backing plate.
The magnet consists of a rod-shaped magnet whose longest width at both ends in the longitudinal direction is wider than the longest width at the center, and an enclosure magnet that surrounds the rod-shaped magnet. This is a sputtering cathode characterized by being wider than the longest width inside the central part.

Here, both ends refer to parts where the length in the longitudinal direction of each both ends is at most 1/3 or less of the total length in the longitudinal direction,
The central portion refers to the remaining portion.

The material of the magnet is preferably one that can maintain a sufficient magnetic field to perform magnetron subbuttering on the target surface even if the space width between the surrounding magnet and the rod-shaped magnet (hereinafter referred to as improved rod-shaped magnet) is narrowed. Examples include permanent magnets such as samarium cobalt and barium ferrite magnets.

If a sufficient magnetic field on the target surface cannot be obtained, ensure a magnetic field sufficient to capture electrons by reducing the thickness of the water cooling jacket or by bringing the magnet closer to the target surface.

It is desirable that the size of the yoke be the same as that of the surrounding magnet in order to prevent unnecessary leakage of the magnetic field of the magnet.

(Function) By shaping the magnet as described above, it became possible to increase the radius of curvature of the electron trapping regions on both end portions of the magnet, making it easier for electrons to wrap around.

(Example) Example 1 As shown in FIG. 1A, an improved rod-shaped magnet 4B with a rectangular central portion and rectangular end portions wider than the rectangular width of the central portion.
and a surrounding magnet 4A surrounding it. The outer shape of the enclosing magnet 4A is rectangular, and the inner shape is such that the center part of the enclosing magnet 4A protrudes more inward than both end parts, corresponding to the center part of the improved rod-shaped magnet 4B. Although the space width between the enclosing magnet 4A and the improved rod-shaped magnet 4B is uniform, the enclosing magnet 4A
The length in the longitudinal direction of the central part of the improved rod-shaped magnet) 4
Since both ends are shorter by the space width than that of B, the space width of that part is wider than the others.

FIG. 4A is a diagram of the film thickness distribution of the substrate when this embodiment is used, and FIG. 4B is a diagram of the film thickness distribution of the substrate when the conventional magnet shown in FIG. 3 is used. Film thickness distribution difference Δ
d is smaller when this embodiment is used.

Embodiment 2 As shown in FIG. 1B, an improved rod-shaped magnet 4B whose central portion is rectangular and both end portions are circular with a diameter longer than the rectangular width of the central portion, and an enclosing magnet 4A surrounding the improved rod-shaped magnet 4B. The enclosing magnet 4A is an improved rod-shaped magnetometer l-4.
It consists of a rectangular central part sandwiching the central part of B with a space gap, and both end parts connecting the central part with a circular bulge. The space width between the surrounding magnet 4A and the improved rod-shaped magnet 4B is uniform.

(Effects of the Invention) According to the present invention, the film thickness distribution of the substrate is improved, and even if the width of the magnet is narrowed, stable discharge can be performed.

[Brief explanation of the drawing]

FIG. 1A is a perspective view of an embodiment of the present invention, FIG. 1B is a perspective view of another embodiment of the present invention, FIG. 2 illustrates a planar magnetron sputtering apparatus, and FIG. 3 is a perspective view of a conventional magnet. FIG. 4A is a diagram of the film thickness distribution of the substrate when Example 1 is used, and FIG. 4B is a diagram of the film thickness distribution of the substrate when the conventional magnet 7 is used. 1: Backing plate, 2: Earth shield, 3: Target, 4: Improved magnet, 4A: Surrounding magnet, 4B: Improved bar magnet, 5: Substrate, 6: Anti-adhesion plate,
7: water channel, 8: yoke, 9: magnet, 9A: square magnet, 9B: bar magnet, 10: thin film, Δd:
Film thickness distribution difference patent applicant Asahi Kasei Koki Co., Ltd. Figure 1A Figure 1B Figure 2 Figure 3

Claims (1)

[Claims] In planar magnetron sputtering equipment, there is a magnet on the back surface of the backing plate, and the magnet is a bar-shaped magnet whose longest width at both ends in the longitudinal direction is wider than the longest width at the center, and a surrounding magnet that surrounds the bar-shaped magnet. A sputtering cathode characterized in that the longest width on the inside of both end portions in the longitudinal direction of the enclosing magnet is wider than the longest width on the inside of the central portion.