JPS61272374A - Sputtering device - Google Patents

Abstract

PURPOSE:To uniformize erosion on the surface of a target and to improve the utilization efficiency of the target by arranging a couple of targets opposite to each other, setting a substrate on the outside of a space region between both targets and giving a confining magnetic field having magnetic polarity reverse to that of the target to the targets. CONSTITUTION:Each target 14 is fixed to each target holder 12, a confining magnetic field is generated from the rear side by using permanent magnets 17 and 17' having magnetic polarity reverse to each other and both targets 14 and 14 are provided in a vacuum vessel 10 in parallel with and opposite to each other. Each substrate holder 15 is placed on the outside of a space region between the targets 14 and 14 and not exposed to plasma and an axis connecting both targets 14 and 14 and the surface of a substrate 16 are made parallel with each other. By such constitution, the movement of secondary electrons in the horizontal direction is controlled by the confining magnetic field, the secondary electrons are confined in the space at the central part between the opposed targets 14 and 14 and the erosion on the surface of the target 14 can be made uniform.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a thin film manufacturing apparatus using the magnetron A'vine method.

[Conventional technology]

A conventional magnetron sputtering apparatus has a structure as shown in FIG. By generating a magnetic field through the target 14, the secondary electrons emitted from the target during sputtering are caused to have a circular motion, which increases the distance the electrons travel, increasing the probability of collision with the atmospheric gas, and increasing the probability of collision with the atmospheric gas. This increases the density and enables high-speed sputtering with low atmospheric gas pressure and low applied voltage.

A permanent magnet or an electromagnet is disposed on the back side of the target as a magnetic field generating means to generate a magnetic field perpendicular to the above-mentioned electric field near the target surface between the target and the substrate holder. For example, the target and magnetic field generating means of a planar magnetron sputtering apparatus, which is currently in widespread use, has a structure as shown in FIG.

[Problem that the invention seeks to solve]

However, the above-mentioned magnetron sufu 4 vine device has the following drawbacks.

Taking the example shown in Figure 2 above, most of the secondary electrons emitted from the target surface are trapped in the toroidal magnetic field formed on the target surface, but most of the secondary electrons emitted from the center of the target The secondary electrons are accelerated in the cathode fall section without being affected by the magnetic field, and collide with the opposing substrate. Collision of these secondary electrons with the substrate causes an increase in the substrate temperature, damage to the substrate and the deposited film, and a composition shift in the compound (or alloy) thin film.

This phenomenon is particularly problematic when a target that is likely to generate negative ions, such as an oxide target, is used and the substrate is bombarded by high-energy particles caused by negative ions.

Further, when the substrate is not flat and has steps (or grooves or holes), adhesion of the film to the side walls of those steps (step coverage) becomes a problem.

Snow J? In the case of sputtering, the sputtered particles repeatedly collide with atmospheric gas atoms or charged particles in the plasma and reach the substrate surface through diffusion, so step coverage is superior to methods such as evaporation, but it still causes ridges. There still remains the problem of shadowing, or self-shadow ink, in which atoms cannot penetrate into the shadows of objects. One method for improving this step coverage is the bias-snokuta method. Is this S/J?
In this method, a positive bias is applied to the substrate during the vine, and ions are attracted and hit the substrate to form a thin film. This inevitably involves problems such as damage to the film and furthermore, atmospheric gas mixing into the film.

Furthermore, the magnetron-snow-weed method suffers from the problem of inefficient target utilization. Taking FIG. 2 as an example, the target surface near the middle of the N and S poles for generating the confinement magnetic field is severely eroded, making the use of the target very inefficient. To deal with this, there have been proposals, for example, to perform suction without moving the target on the magnetic field generating means, but no practical solution has been found.

SUMMARY OF THE INVENTION An object of the present invention is to provide a sputtering apparatus that solves the above-mentioned problems and improves target utilization efficiency.

[Means for solving problems]

In the present invention, first and second chambers are arranged parallel to each other in a vacuum container. a second target, a power supply means for supplying power to the target, and a region between the first and second targets in the vicinity of the surfaces of the first and second targets to which an electric field is applied by the power supply means; first and second magnetic field generating means for forming orthogonal magnetic fields through the target; and located at positions spatially orthogonal to the target outside the spatial region between the first and second targets. The sputtering apparatus is characterized in that the first and second mutually opposing magnetic field generating means have magnetically opposite polarities.

〔Example〕

Next, one embodiment of the present invention will be described using the drawings. FIG. 1 is a schematic vertical sectional view of an embodiment of the present invention. The target part fixes the target 14 to the target holder 12 in the same way as in conventional magnetron sputtering equipment.
A magnetic field is generated on the target surface using a permanent magnet 17 from the back side of the target holder 12 (see FIG. 2).

After preparing two sets of such target systems and making sure that their respective permanent magnets 17° and 17' have opposite polarities, the vacuum vessel 1 is placed so that each target faces parallel to each other.
0 through an insulated port 11.

Next, the substrate holder 15 is placed outside the spatial region between the targets as shown in the figure, so as not to be exposed to plasma, and so that the axis connecting the targets is parallel to the substrate surface. 13 is a shield, 16 is a substrate, 20 is a gas introduction system, 21 is an exhaust system, and 3o is a power source. Although not shown in the figure, since the target is heated during sputtering, a cooling means such as water cooling is required, and a shutter or the like may be required to shield the front of the substrate as necessary. This is a well-known fact. In addition, in FIG. 1, the substrate l6
are placed on the two holders 15 on the left and right,
It is clear from the content of the invention that the substrate can be placed all around the target.

In the sputtering apparatus of the present invention, magnetron sputtering is performed on upper and lower targets, and particles that are sputtered from each target and ejected in an oblique direction reach the substrate surface. As mentioned earlier, some secondary electrons and negative ions that fly out perpendicularly from the target surface are not confined by the confining magnetic field and travel straight, but in the sputtering apparatus of the present invention, the substrate is placed facing the target. Since the sputter is not sputtered, it does not collide with the substrate and cause various adverse effects unlike ordinary magnetron sputtering.

Also, since the board surface is diagonal when viewed from the target,
Even if there is a step on the substrate, the positional relationship is such that the sputtered particles fly directly to and adhere to the side wall of the step, so that better step coverage can be obtained than in the conventional S/J ivy method.

Furthermore, it is generally known that the directionality of particles that are sputtered and ejected from a target generally exhibits a cosine (easing) distribution with respect to the angle from the normal direction of the target surface. Even with such a substrate arrangement, a sufficiently high deposition rate can be obtained. Figure 3 shows the uniformity of the film thickness when the film is deposited using this method, using circular targets with a radius of R, the distance between the targets is 2R, and the distance from the center axis between the targets to the substrate surface. This figure shows the film thickness distribution within the substrate plane (in the vertical direction) when the distance to the substrate is 2R. As described above, the present invention does not impair the high deposition rate that is a feature of the conventional magnetron/Sumi 4-tube apparatus, and can even be said to be better than the conventional apparatus in terms of film thickness uniformity.

In addition, as shown in the embodiment of FIG.
17.17' has magnetically opposite polarity, so
The magnetic field distribution in the space between the targets is as shown in FIG. That is, the confinement magnetic field on the target surface and the magnetic field between the targets can be considered separately.

As mentioned above, magnetron snogging is performed on each target by the confining magnetic field on the target surface. However, as mentioned earlier, in general magnetron sputtering, there are secondary electrons and negative ions that are not confined by the magnetic field near the center of the target and travel straight (this is irrelevant because there is a shield ring at the end of the target). ). In the snow and ivy device of the present invention, such secondary electrons are reflected by the cathode falling part of the target on the opposite side and try to move toward the shield ring (which acts as an anode) while reciprocating between both targets. , such lateral movement of electrons is suppressed by the perpendicular magnetic field component between the two tardats shown in FIG. 4, and they are eventually confined in the space facing each other near the center of the target.

In this way, the plasma density in the spatial region near the center of the target is also increased.

Therefore, it is possible to prevent extremely severe erosion only in the vicinity of the center of the confining magnetic field as in normal magnetron sputtering, and to achieve uniform erosion of the target surface.

〔Effect of the invention〕

As explained above, according to the present invention, the targets of the conventional magnetron ST4 vine method are arranged in a pair facing each other, and the substrate is positioned outside the spatial region between the targets. This prevents high-energy particles such as secondary electrons or negative ions from colliding with the substrate, preventing an increase in substrate temperature and damage to the substrate or attached film. Step coverage can be improved by allowing the particles to fly in, yet by applying a confining field of magnetically opposite polarity to the opposing targets, the secondary electrons from the above-mentioned target can be moved near the center of the target. This has the effect of forming a confined high-density plasma in a spatial region, thereby achieving uniform erosion of the target surface and improving target utilization efficiency.

[Brief explanation of drawings]

FIG. 1 is a schematic vertical cross-sectional view of an embodiment of the Sumi-4 Ivy apparatus according to the present invention, FIG. 2 is a cross-sectional view of a target and magnetic field generating means, and FIG. 3 is a film deposited by the Sumi-4 Ivy apparatus according to the present invention. FIG. 4 is a sectional view of a target and magnetic field generating means of a sputtering apparatus according to the present invention, and FIG. 5 is a schematic vertical sectional view of a conventional magnetron sputtering apparatus. 10: Vacuum container, 11: Insulated port, 12: Targt holder, 13: Shield, 14: Targt, 15
: Substrate holder, 16: Substrate, 17: Permanent magnet, 20:
Gas introduction system, 21: Exhaust system, 30: 2% of power supply board Figure 3

Claims (1)

[Claims] (1) First and second facing parallel to each other in a vacuum container
a target, a power supply means for supplying power to the target, and an electric field perpendicular to the electric field by the power supply means in a region near the first and second target surfaces between the first and second targets. first and second magnetic field generating means for forming a magnetic field through the target, and located at a position spatially orthogonal to the target outside the spatial region between the first and second targets; 1. A sputtering apparatus comprising a substrate holder, wherein the first and second mutually opposing magnetic field generating means have magnetically opposite polarities.