JPH0726203B2 - Magnetron sputtering equipment - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film generator used in the fields of semiconductors and magnetic recording materials, and more particularly to a magnetron sputtering apparatus.

2. Description of the Related Art FIG. 3 shows a structure of a sputtering source and a sputtering chamber of a conventional most common magnetron sputtering apparatus. In the figure, 1 and 2 are magnets, and the polarities of the adjacent magnetic poles are arranged opposite to each other. Reference numeral 3 is a cathode, 4 is a target of a required metal serving as a sputtering source, 5
Is an anode, 6 is a substrate, 7 is a vacuum chamber, 8 is a target 4
The line of magnetic force penetrating through is the target surface before consumption.

One of the features of magnetron sputtering is the effect of improving the sputtering rate, but at this time, the target surface to be sputtered is limited to the vicinity of the place where the electric field and the magnetic field intersect at right angles. Therefore, the cross section of the target erosion region is V-shaped, and the target utilization rate is as low as 20 to 40%.

In order to improve such a low utilization rate of the target, a method has been devised, for example, as disclosed in Japanese Patent Application Laid-Open No. 51-86083, in which the magnetic flux density distribution is changed to improve the wear region of the target. FIG. 4 shows an example of another method conventionally used to improve the utilization factor of the target. The positions of the magnets 1 and 2 are reciprocated in the direction of the arrow during sputtering to generate an orthogonal electromagnetic field. By moving the position of
The structure of the sputtering source in which the area of the target 4 to be sputtered is increased is shown.

By doing so, it is known that the cross section of the consumable region of the target becomes a relatively gentle V shape, the consumable region is expanded, and the utilization efficiency is improved to about 50 to 60%. There is a drawback that a large-scale mechanism is required to reciprocate a heavy object.

Even if the magnet is rotated or swung within a limited range, the erosion area on the surface of the target 4 is
As shown in FIGS. A and b, it became annular and the erosion area was not sufficiently expanded, and the improvement effect was not satisfactory.

Another problem with the conventional thin film formation by the sputtering method is the film thickness distribution of the film formed on the substrate.
Regarding the film thickness distribution of the film produced by the conventional method shown in FIGS. 3 and 4, the film thickness is reduced in the peripheral portion of the target as compared with the central portion as shown in FIG. To improve this,
A method of adjusting the amount of film formation by rotating the substrate on a different axis from the target, or by providing a fixed or rotating shield plate (baffle plate) near the center of the target at the expense of the generation speed is used. Was there.

However, the most efficient circular sputtering source is used for a group of substrates that are circular as a whole, such as a circular substrate or a plurality of substrates arranged on the same circumference,
In the case of forming a film without making the substrate and the sputtering source move relative to each other, this structure is not suitable in view of the film thickness uniformity.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention The present invention improves the utilization efficiency of a target, which is a drawback of such a technique, and improves the uniformity of film thickness with respect to a substrate group arranged in a circle, Moreover, the structure is simple,
An object is to provide a sputter source that is small.

Means for Solving the Problems To achieve this object, the present invention arranges the surface of a target in a reduced pressure, inert gas atmosphere and applies an electric field to the surface of the target to generate plasma in the inert gas. A mechanism, a magnet assembly having a plurality of magnets radially arranged so as to face the back surface of the target, and a drive mechanism for rotating the magnet assembly with the center of the magnet assembly as a rotation center, The magnets are arranged with a magnetic gap between the magnets, and the magnetic gap extends in the radial direction of the rotating magnet assembly.

Function With this configuration, it is possible to focus the ions linearly between the radial magnetic gaps and widen the target's consumable region from the center to the outer periphery of the target. The wear area can be maximized.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 11 is a target, which is adhered to and held by the backing plate 12. Further, on the back side of the backing plate 12, a plurality of magnets 13 and 14 are radially arranged with the surface opposite to the target 11 fixed on a back yoke 15 made of a ferromagnetic material such as permalloy. Is configured. A rotating shaft 16 is attached to the center of the back yoke 15, and the back yoke 15 rotates coaxially with the target 11 by a driving mechanism (not shown).

As shown in FIG. 1b, the magnets 13 and 14 are magnets 1.
The magnets are magnetized in the thickness direction of 3, 14 and are alternately arranged with a gap as a magnetic gap. Further, as shown in FIG. 1A, the magnetic gap gradually increases from the central portion side toward the outer peripheral portion side so that the magnetic gap length 17 becomes about 0.7 at the outer peripheral portion side of the magnet assembly. It is shortened to.

The atmosphere in the vacuum chamber (not shown in FIG. 1) of the sputtering apparatus having the sputtering source configured as described above is set to about 10 ^−3.
When the voltage of 1.5 KV is applied between the anode on the substrate side and the cathode on the target 11 side while keeping the voltage at Torr, plasma is generated in the region where the magnetic field and the electric field are orthogonal to each other. This plasma causes sputtering to start from a region on the target surface where plasma is generated.

As shown in FIGS. 2A and 2B, the consumption state of the target surface after repeated sputtering is uniformly consumed radially from the center of the target.

Further, FIG. 6 shows the distribution of the film thickness produced when the magnet assembly constructed as shown in FIG. 2 is sputtered while rotating, and on a concentric circle like the conventional method shown in FIG. Significantly improved film thickness distribution compared to the magnet assembly arranged in.

In the configuration of the present invention, unlike the prior art, the linear magnetic gaps are arranged in a radial pattern, so that the consumption surface of the target is also linear as shown in FIG. In this way, since the consumable surface is formed radially in the radial direction of the target on the entire surface of the target, it is possible to effectively use the entire surface of the target by rotating and moving the mounting angle of the target appropriately, and to improve the utilization efficiency. It is possible to greatly improve.

Further, instead of rotating the target, by rotating this magnet assembly continuously during the sputtering with the above-described rotation axis, the consumption region can be made substantially uniform over the entire surface of the target.

Although an appropriate value can be selected for the gap length, the sputtering rate can be improved by increasing the comparison of the areas of the gap portions in the total area of the target. However, on the other hand, if the number of magnetic gaps is increased, the volume (cross-sectional area in the axial direction) of each magnet is reduced, and the magnetic flux density is reduced. Therefore, 2 to 8 poles are generally suitable.
When the magnets are arranged in this way, the magnetic gap length becomes shorter than that in the conventional magnetic circuit, and therefore, there is an advantage that the volume (weight) of each magnet can be reduced.

Also, by arranging the magnetic gap length on the outer peripheral side shorter than that on the central side of the magnet assembly, the magnetic flux density on the outer peripheral side can be improved, and the center of rotation when the magnet assembly is rotated. It is possible to obtain a uniform sputter rate over the entire target surface by correcting the difference in the sputter rate per unit area between the center side and the outer side of the target caused by the difference in the peripheral speed from the outer side to the outer side. Great effect.

EFFECTS OF THE INVENTION As described above, according to the present invention, in the magnetron sputtering apparatus, the intensity distribution of the magnetic field in the vicinity of the target surface is changed from an annular shape to a radial shape and sputtering is performed while rotating the magnet assembly, thereby eliminating all ferromagnetic materials. The consumption region of the target can be expanded over the entire surface of the target regardless of the sputtering material or any film forming condition, and the utilization efficiency of the target can be significantly improved.

Furthermore, a unit on the center side and the outer peripheral side of the target caused by a difference in peripheral speed when the magnet assembly is rotated by shortening the magnetic gap length on the outer peripheral side as compared to the central side of the magnet assembly. Since it is possible to correct the difference in the sputter rate around the target and obtain a uniform sputter rate over the entire surface of the target, it is possible to significantly improve the variation in the film thickness of the film formed on the substrate.

Further, in the present invention, since the entire surface of the target can be used evenly, it is possible to reduce the thickness of the target to be used, which can reduce the target cost and improve the magnetic flux density on the target surface on the substrate side. Has the effect of becoming larger.

At the same time, since the magnet assembly according to the present invention has a shorter magnetic gap length than the conventional one, it is possible to obtain the same magnetic flux density as that of the conventional one with a small magnetic energy, which enables downsizing of the magnet, cost reduction of the magnet, and rotation mechanism. It has many industrial effects such as downsizing.

Although the present invention has been described with reference to the example in which the permanent magnets are used in the magnet assembly, it is clear that the magnetic force source can obtain the same effect even when the electromagnet is used, and that the same effect can be obtained when the target is rectangular. is there.

[Brief description of drawings]

1A and 1B are a front view and a sectional view in the vicinity of a magnet of a sputtering apparatus according to an embodiment of the present invention, and FIGS. 2A and 2B are explanatory views showing the distribution of the erosion region of a target of the apparatus, and FIG. , Fig. 4 is a cross-sectional view near the magnet of the conventional magnetron sputtering apparatus, Fig. 5a,
FIG. 6b is an explanatory view showing the distribution of the erosion region of the target in the conventional example, and FIG. 6 is a film thickness distribution characteristic diagram of the film formed in the conventional example and the present invention. 11 …… Target, 12 …… Backing plate, 13,14
…… Magnet, 15 …… Back yoke, 17 …… Magnetic gap length.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hideyuki Tanigawa, 1006 Kadoma, Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Kazuo Ogata, 1006, Kadoma, Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. 56) References: 57-154768 (JP, U)

Claims (2)

[Claims] 1. A mechanism for arranging the surface of a target in a depressurized atmosphere of an inert gas, applying an electric field to the surface of the target to generate plasma in the inert gas, and a mechanism for radially radiating the target so as to face the back surface of the target. A magnet assembly having a plurality of magnets arranged on the magnet assembly, and a drive mechanism for rotating the magnet assembly with the center of the magnet assembly as a rotation center, and the magnets are arranged with a magnetic gap between the magnets. The magnetron sputtering apparatus is characterized in that the magnetic gap extends in a radial direction of the rotating magnet assembly. 2. The magnetron sputtering device according to claim 1, wherein the magnetic gap length of the magnetic gap is shorter on the outer peripheral side than on the central side of rotation of the magnet assembly.