JPS61190070A - Sputter device - Google Patents

Abstract

PURPOSE:To make the formation of a sputtered film having good quality possible by disposing an electrode on the inside of a high-frequency coil which is provided in the space between a target disposed in a hermetically held vessel and a substrate and generates plasma and controlling the potential of the plasma. CONSTITUTION:The cylindrical electrode 8 is provided on the inside of the high-frequency coil 5 connected to a high-frequency power source 7 to generate the ground potential and to form the stable plasma by stabilizing the plasma potential in a sputter device which executes sputtering by holding the target 12 consisting of a film forming material and the substrate 17 to be formed with the film so as to face each other in the vessel 1 in which gaseous Ar or the like is maintained, generating the plasma between the target 12 and the substrate 17 by the above-mentioned coil 5 and bringing the plasma ions generated in said plasma into collision against the target 12 maintained under the negative potential by a power source 16. The potentials of the target 12 and the substrate 17 connected to a power source 20 are respectively independently and optionally controlled. The formation of the film having the good characteristics on the substrate 17 is thus made possible.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a sputtering device using a high frequency power source for plasma generation, and in particular, to a sputtering device that uses a high frequency power source to generate plasma, and in particular, to produce a high quality sputtered film by freely controlling the plasma potential. Concerning the structure to be formed.

[Background of the invention]

The sputtering method is known as a method for thinning films of various materials, and various improvements have been made depending on the application, but basically, the sputtering method is made by setting the substrate on which the film is to be formed and the vacuum container at the same potential, and In many cases, a direct current or high frequency source is connected between the targets, which are sputtering materials, to generate plasma discharge, and a film is formed by this action. At this time, the plasma potential depends on the potential of surrounding exposed members and is generally close to the ground potential, which is the potential of the vacuum vessel. On the other hand, it has been found that the bias voltage, which is the difference in substrate potential with respect to plasma potential, affects film characteristics depending on the sputtering material.

For this reason, a method has also been attempted in which the substrate is held insulated from the vacuum container, and during this time, a direct current or direct current is applied for film formation from the outside. However, even with this, the plasma injection area force,
The voltage between the plasma and the target, which greatly affects the dK of the sputtered particles, cannot be arbitrarily and independently controlled.

For example, as in Japanese Patent Application Laid-Open No. 54-103789, there is a method in which power is input to the plasma via a coil using high frequency wL#, but this method is based on the plasma input area force, plasma potential, substrate potential, and target potential. cannot be controlled independently.

[Purpose of the invention]

The purpose of the present invention is to arbitrarily and independently control the plasma input area force, the substrate potential and the target potential with respect to the vacuum container,
The object of the present invention is to provide a sputtering apparatus t that can obtain good quality film characteristics.

[Wt essential points of invention]

The present invention will be explained in detail using the embodiment shown in FIG.

In FIG. 1, a vacuum container 1 is provided with a gas inlet 2 and a gas exhaust port 3, and is connected to a ground potential by a ground wire 4. Gas supply port 2 is for gas cylinder, pressure reducing valve,
It is connected to a gas supply system consisting of a gas flow rate vI4 tank, a gas sealing valve, etc., and the gas exhaust port 3 is connected to a gas exhaust device such as a vacuum pump. Before starting sputtering, the inside of the vacuum container 1 is tightened to, for example, 10-II Torr or less using a vacuum pump, and Ar gas or the like is supplied while controlling the flow rate to all EL using the gas supply system, and the pressure is increased to, for example, 10'''. ~10'・
Maintain the desired value such as rorr.

The high frequency coil 5 is held within the vacuum vessel 1 by an insulating support snout 6, and both ends thereof are connected to a high frequency power source 7 including an impedance matching circuit. The high frequency coil 5 has a tubular configuration, and cooling water can be passed through the coil to prevent heating. The high frequency power source 7 often uses an industrially assigned frequency of 13.56 MHz. When a suitable amount of power is applied to the high frequency coil 5, a high frequency cylindrical electric field is induced by electromagnetic induction, and a plasma density is obtained by glow discharge corresponding to the injected power.

(by the cylindrical polarization 8ri insulator 9), by the introduction terminal 11 held in the Ic empty container 1 and sealed with the insulator 10,
electrically connected to the outside. In this example, the ground potential is used to simplify the configuration, but as a matter of course,
Can be set to any potential.

The potential of the plasma induced by the above-mentioned high frequency coil 5 is the same as that of the cylinder 1!7L, which has a large exposed area to the plasma.
Under the influence of pole 8, it becomes equal to ground potential.

The target 12Vi is surrounded by an earth shield 13 for preventing sputtering from a material other than the target surface, and is supported by a conductive target holder 15 surrounded by an insulator 14. . Furthermore, since a negative potential is applied to the plasma by the power supply 16, the positive ions in the plasma are accelerated by the electric field created on the opposite surface of the target 12 and collide with the target 12. As a result, most of the atoms constituting the target 12 are emitted from the surface of the target 120 as neutral sputtered particles. Since the target 12 is heated by the energy of the incident positive ions and reaches a high temperature, it is often cooled by flowing cooling water into the target holder 15, but this is not shown in the figure.

The substrate 17 is a substrate holder 1 sealed with an insulator 18.
9 and is provided with a luminous position by a power source 20. The potential in this case is not very large and the optimum value differs depending on the film forming material, but at most it is negative 1 to the plasma potential.
00V, and can often be used as a ground.

Depending on the substrate temperature, the sputtered particles emitted from the target 12 accumulate on the surface of the substrate 17, forming an initial film.

In this configuration example, 9 (not shown) is usually equipped with a shutter mechanism installed in front of the substrate to prevent abnormal spatter during press sputtering, and various analysis and measurement devices for monitoring the equipment status and plasma status. However, these are included in the present invention.

In this embodiment, the cylindrical electrode 8 is provided inside the high-frequency coil 5 and an independent potential is applied to it, so that the potential distribution generated on the surface of the high-frequency coil 5 does not affect the plasma potential. Stable plasma can be obtained.

[Embodiments of the invention]

FIGS. 2 and 3 show a structure in which a slit is provided in the axial direction of the cylindrical electrode 8 in order to prevent loss due to eddy current induced by high frequency current. In FIG. 2, electrode portions 21 and insulating portions 22 are alternately stretched together, and a conductor 23 that applies a potential
are connected individually. In Figure 3, the cylindrical insulator 2
Fig. 4 shows a structure in which a magnet 25 for generating a cusp magnetic field is provided on the outside of a cylindrical electrode 8, and a magnet 25 for generating a cusp magnetic field is thereby generated. , the plasma is confined and the loss of electrons to the cylindrical electrode 8 is reduced. Thereby, the efficiency of plasma generation by the high frequency current flowing through the high frequency coil 5 can be improved.

In FIG. 5, a space is provided between the target 12 and the target holder 13, and a magnetron magnet 27 for generating a magnetic field for plasma confinement on the surface of the target 12 is arranged in the space.

Furthermore, an annular magnet 25 for generating a cusp magnetic field is installed around the outer periphery of the cylindrical electrode 8. As a result, target 1
A magnetic field 26 is obtained continuously from the two surfaces to the upper end of the cylindrical electrode 8, and the plasma generation efficiency can be further improved.

FIG. 6 shows the vacuum vessel 1 used as a cylindrical electrode for applying a potential to plasma. In this embodiment, when the vacuum container 1 is to be used at a potential other than the ground potential, the entire vacuum container 1 must be insulated and electrically suspended from the earth. There is an advantage that it can be done.

FIG. 7 shows how to apply a target potential when the target 12 is an insulator. In the target holder 13,
A high frequency power source 28 including an impedance matching circuit is connected to apply a high frequency voltage. With this configuration, a DC bias voltage is induced on the target surface. This method can also be applied when the substrate is an insulator, and similar effects can be obtained.

In the present invention, plasma is generated by the high-frequency coil 5 and a plasma potential is applied by the cylindrical electrode 8. Therefore, according to this configuration example, an arbitrary voltage for the plasma can be applied to the insulating substrate, the target, or both. can give.

In FIG. 8, the substrate, via the impedance matching circuit 29,
A configuration example will be shown in which the high frequency power source 7 for the high frequency coil is shared in order to provide a target potential. An impedance matching circuit is generally configured by a combination of L and C, but there are various ways to configure it, and the configuration is not limited to the one shown in this figure. Further, the bias voltage can be set arbitrarily by changing the constituent elements. According to this configuration example, one high-frequency power source can be shared, so the overall configuration of the device can be simplified.

〔Effect of the invention〕

According to the present invention, the plasma injection power, plasma potential, target potential, and substrate potential can be controlled independently, and the potential distribution generated in the high-frequency coil does not affect the plasma, so the plasma can be stably controlled under desired conditions. This makes it possible to realize high-quality sputtered films.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a main part of one embodiment of the present invention, and FIGS. 2 to 4 are partial cross sections No. 61ffl showing different embodiments.
, d are main part sectional views showing different embodiments. 1... Container, 12... Target, 17... Substrate, 7... High frequency power supply, 5... High frequency coil, Death...
Third electrode, 21... electrode part, 22... insulating part.

Claims (1)

[Scope of Claims] 1. A device consisting of a pair of targets made of a film forming material and a substrate on which a film is to be formed, which are held in an airtight container, in which a gap between the target and the substrate is provided. generates plasma,
A sputtering apparatus characterized in that a high-frequency power source and a high-frequency coil are provided for injecting power to maintain this, and an electrode for controlling the potential of the plasma is provided inside the high-frequency coil. 2. The sputtering apparatus according to claim 1, wherein the electrode is a combination of electrode parts and insulating parts alternately. 3. The sputtering apparatus according to claim 1, wherein each potential of the electrode, the target, and the substrate can be controlled by a potential difference between at least two of them. 4. The sputtering apparatus according to claim 3, wherein the potential of the substrate or the target is applied with a DC voltage or a high-frequency AC voltage.