JPH0543788B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a thin film forming apparatus using a sputtering method.

(Prior art and its problems) The general structure of a conventional sputtering device is as shown in FIG. 4, a sectional view of which is shown. (This device is rotationally symmetrical.) 1 is a target, 2 is a target electrode shield, 3 and 8 are impedance conversion units, 4,
9 is a DC power supply or AC power supply, 5 is a substrate, 6 is a substrate stand, 7 is a substrate electrode shield, 10 is a vacuum chamber, 11 is a target side electrode (as shown in FIG. 5) incorporating a magnetic field generator 110, 12 is the substrate side electrode.

What is shown in FIG. 5 is the above-mentioned magnetic field generating device 11.
This is the positional relationship between the N outer magnetic pole 115 of 0, the S center magnetic pole 114, the lines of magnetic force 13a to 13d generated therefrom, the target side electrode shield 2, and the substrate 5.

In the case of the magnetic pole arrangement as shown in Fig. 5, the lines of magnetic force 13a
~13d etc. originate from the N magnetic pole 115 on the outer periphery and enter the S magnetic pole 114 at the center.

Now, if we consider the electrons that rotate and advance along the group of magnetic lines of force 13d1 to 13d to 13d2 that penetrate the surface of the substrate 5 among these lines of magnetic force, the electrons flying out from the target will spiral around the curved lines of magnetic force. make a rotational movement. As the magnetic field lines move away from the target surface, the magnetic field strength becomes weaker, so the electrons are initially subjected to a force that pushes them away from the target surface. As the electron approaches the target surface, the magnetic field becomes stronger, so the electron receives a force in the opposite direction. Therefore, the electrons leave the target surface, run through space, and repeat reciprocating motion along a single curved line of magnetic force that reaches the target surface.

On the other hand, the electrons that move in a spiral manner while being wrapped around the magnetic lines of force toward the substrate also become weaker as the lines of magnetic force move away from the target surface, so they reach the substrate while receiving a force that pushes them away from the target surface. At this time, the electrons have high energy because they are subjected to a force that pushes them out from the target surface, and when the substrate is bombarded by these electrons, the crystals of the substrate are broken, causing damage to the substrate. Further, when high-energy electrons bombard the substrate, thermal energy is generated on the substrate, which heats the substrate and causes damage to the substrate.

Note that the magnetic field formed by the lines of magnetic force directed toward the substrate is hereinafter referred to as a "divergent magnetic field" in this specification.

This impact has conventionally been ignored as it is not very severe, but with recent high-performance thin films, even such impact can become a problem.

Furthermore, some bias sputtering devices are equipped with a magnetic field generating mechanism not only on the target side but also inside the substrate side electrode, or at a third position other than the target side and the substrate side. Even in such a case, if the group of magnetic lines of force penetrating the substrate surface creates a diverging magnetic field that opens toward the substrate, the same problem as described above occurs.

(Object of the Invention) An object of the present invention is to provide a bias sputtering device that solves the above problems and prevents high-energy electrons from being incident on a substrate and causing damage due to a divergent magnetic field.

(Structure of the Invention) In order to achieve the above object, the present invention forms a space by a target-side electrode and a substrate-side electrode, and runs in the space from the target surface provided on the target-side electrode. A magnetic field generating device that forms curved lines of magnetic force reaching the target surface and lines of magnetic force directed toward the substrate provided on the substrate side electrode is attached to the target side electrode, and a high frequency is applied to both or one of the target side electrode and the substrate side electrode. Alternatively, in a bias sputtering apparatus that forms a thin film by applying a DC voltage, at least one shield is provided to block lines of magnetic force directed toward the substrate.

Furthermore, the effect is further enhanced by using the shield as a conductive object to which a ground potential or a positive potential is applied.

(Function) According to the above configuration, the movement of electrons accelerated by the diverging magnetic field toward the substrate is inhibited by the shielding object, thereby reducing the energy of charged particles incident on the substrate and reducing damage to the substrate surface. I can do it.

(Embodiment) FIG. 1 is a schematic cross-sectional view of a bias sputtering device showing a first embodiment of the present invention, and the same members as in FIG. 4 are given the same reference numerals. Therefore, the explanation will be omitted.

Magnetic field generator 110, which is the key point of the present invention
FIG. 2 shows the relationship between the magnetic field, the lines of magnetic force emanating from it, and the target-side electrode shield 2, which is a shield that is a feature of the present invention.

The group of magnetic lines of force 13d1 to 13d to 13d2 that penetrate the surface of the substrate 5 and cause damage to the substrate are as follows:
A portion close to the target is blocked by an extended tip 25 of the target side electrode shield 2.

Therefore, as the electrons rotate and advance along these lines of magnetic force, their progress toward the substrate is blocked at the base of the peripheral portion 20 where the degree of divergence is strongest among the divergent magnetic fields, and the electrons are directed downward in the direction of the magnetic field. The force that was once accelerated is weakened.

Part 2 where the shield plate 2 crosses the magnetic lines of force
Since plasma generation is prevented near 5,
This also reduces the incidence of electrons on the substrate 5 and reduces damage to the substrate surface.

FIG. 3 shows a second embodiment of the present invention in which a center shield plate 16 is further added to the above as a countermeasure against the divergent magnetic field existing in the center portion 21. 16 prevents the generation of electrons near the center of the target, and further reduces the incidence of high-energy charged particles on the substrate.

In addition to the above, the magnetic field line shield of the present invention includes 22,
23, etc., or even if they are installed in a superimposed manner, each produces a considerable effect, but experiments have shown that the tip of the shield 2 in Figure 1. It has already been found that extension 25 alone has a sufficient effect.

Furthermore, for example, a patent application filed in 1980 by the same applicant
Publication No. 247627 discloses an invention regarding a bias sputtering device in which a magnetic field generating device is also provided on the substrate side, and the present invention produces great effects even when applied to the magnetic field dispersion section of such a device. It is clear that the same applies when the magnetic field generator is located at a location other than the target side or the substrate side.

In addition, the shield plates 2 and 16, which are shields for magnetic lines of force according to the present invention, are made of a conductive material and can be made by applying a ground potential or a positive potential to capture electrons. It has been found to greatly enhance the effectiveness.

(Effects of the Invention) As described above, the present invention has the effect of providing a bias sputtering device that prevents high-energy charged particles from entering a substrate and causing damage due to a divergent magnetic field.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a first embodiment of a bias sputtering apparatus of the present invention. Figure 2 is a diagram of the lines of magnetic force. FIG. 3 is a diagram of the configuration and magnetic lines of force of a second embodiment of the bias sputtering device of the present invention. Fourth
The figure is a schematic cross-sectional view of a conventional bias sputtering device. Figure 5 is a diagram of the lines of magnetic force. 1...Target, 2...Target side electrode shield, 3, 8...Impedance conversion unit, 4, 9...Power source, 5...Substrate, 6...Substrate stand, 7...Substrate side electrode shield, 8... ...Substrate, 1
0...Vacuum chamber, 11...Target side electrode, 12...Substrate side electrode, 13a to 13d, 13
d1, 13d2... Lines of magnetic force, 110... Magnetic field generator, 114... Center magnetic pole, 115... Outer magnetic pole, 16... Center shield plate.

Claims (1)

[Scope of Claims] 1. A space is formed by a target side electrode and a substrate side electrode, and curved lines of magnetic force exit from the target surface provided on the target side electrode, run through the space, and reach the target surface, and the substrate side A magnetic field generating device that forms magnetic lines of force directed toward the substrate provided on the electrode is attached to the target side electrode, and a high frequency or DC voltage is applied to both or one of the target side electrode and the substrate side electrode to form a thin film. A bias sputtering apparatus characterized in that the bias sputtering apparatus is provided with at least one shielding object that blocks lines of magnetic force directed toward the substrate. 2. The bias sputtering device according to claim 1, wherein the shield is a conductive object to which a ground potential or a positive potential is applied.