JP2711383B2 - Ion beam sputtering equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ion beam sputtering apparatus capable of forming a high-quality thin film on a film forming substrate.

[0002]

2. Description of the Related Art In a conventional ion beam sputtering apparatus, for example, as shown in FIG. 3, a sputtering target 3 and a film forming substrate 2 are housed in a chamber 1 for keeping a region where a sputtering process is performed at a vacuum. An ion (particle) beam is incident on the sputtering target 3 at a high speed from a sputtering ion source 5 attached to the wall of the chamber 1, and atoms (particles) of a substance constituting the target 3 by the ions entering the target 3. Is emitted upward from the surface thereof, and these sputtered-out atoms are attached to the substrate 2 to form a thin film of the target material on the substrate 2. During the process, the inside of the chamber 1 is maintained in a vacuum state by the vacuum exhaust system 6.

[0003] The ion beam sputtering method is known as a method capable of forming a high-quality film having a higher density as compared with a vacuum evaporation method or the like. Focusing on increasing membrane speed,
The components of the ion source 5, the target 3, and the substrate 2 are interconnected so that the particles of the target material sputtered out by the entry of the ion beam reach the substrate 2 most efficiently and the sputtering efficiency is increased. Was adjusted and placed. Further, the chamber size has been considered to be as small as possible within a range that can accommodate these components so that a high vacuum can be easily obtained.

In the case of the ion beam sputtering apparatus shown in FIG. 3, the target 3 is held by a target holder 4 and disposed substantially horizontally at the bottom of the chamber 1 so that the film can be formed efficiently. Numeral 2 is held in a substrate holder (not shown) and disposed in the chamber 1 obliquely above and to the left of the target 3 so that the substrate surface is inclined with respect to the target surface. The ion beam from the ion source 5 is applied to the target surface. Atoms incident at a large incident angle and sputtered out of the target 3 efficiently fly to the substrate 2.

[0005]

As described above, in the conventional ion beam sputtering apparatus having the arrangement emphasizing the film forming efficiency, of the high-speed particles generated from the ion source and incident on the sputtering target, the target is sputtered out. A considerable amount of particles that are reflected or scattered on the target surface without entering (not penetrating) reach the substrate. Since these particles reach the substrate at high speed without losing the original kinetic energy sufficiently, when they enter the substrate, they are formed by re-sputtering out the film material deposited on the substrate or roughening the film surface. This was a cause of deteriorating the characteristics of the film.

Further, when high-speed particles reflected or scattered on the target material surface enter the chamber inner wall or an internal mechanism (a structure such as a holder arranged in the chamber 1),
These constituent materials are sputtered out, and these protruding constituent atoms are mixed as impurities into the film formed on the substrate, thereby deteriorating the film quality. An object of the present invention is to prevent high-speed particles reflected or scattered on the surface of a sputtering target from flying to a substrate and to prevent impurities from being mixed into a film being formed, thereby forming a high-quality thin film on a substrate. An object of the present invention is to provide an ion beam sputtering apparatus which can be formed thereon.

[0007]

According to the present invention, a sputtering target and a film-forming substrate are arranged in a chamber for forming a vacuum region at a predetermined interval so as to face each other. The ion source is installed on the chamber wall so that the high-speed ion beam is obliquely incident on the target surface from between the target and the substrate, and is reflected by the target surface on the chamber wall almost opposite to the ion source. Alternatively, a trap portion for trapping the scattered high-speed particles is provided, and the substrate is disposed at a position where the high-speed particles reflected or scattered on the target surface are difficult to fly. The portion is trapped in the trap portion so as not to collide with the inner wall of the chamber or the internal mechanism.

[0008]

According to the structure of the present invention, since the high-speed ion beam from the sputtering ion source is obliquely incident on the target surface from between the target and the substrate, high-speed particles reflected or scattered on the target surface are obtained. Almost do not scatter upward, but scatter obliquely at an exit angle similar to the incident angle. Therefore, the reflected or scattered high-speed particles do not fly to the substrate located substantially above the target in a direction different from the emission trajectory of these reflected or scattered high-speed particles. There is no risk of deteriorating the characteristics. In addition, most of the high-speed particles reflected or scattered on the target surface are trapped in the trap portion, and the atoms of the constituent materials of the inner wall of the chamber and the internal mechanism are sputtered out due to the intrusion of these high-speed particles, so that the film during the film formation is formed. It can be prevented from being mixed into the film.

[0009]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a schematic configuration diagram showing one embodiment of an ion beam sputtering apparatus according to the present invention, in which a sputtering target 3 and a film forming substrate 2 are placed in a chamber 11 for forming a vacuum region for performing a sputtering process. Are arranged facing each other at intervals of. In the illustrated example, the sputtering target 3 is held by a target holder 4 and is disposed in a substantially horizontal direction at the bottom in the chamber 11, and the film-forming substrate 2 is held by a substrate holder (not shown) and slightly over the target 3. It is arranged near the ion source so as to face the target 3. In the figure, two types of target material films 3 can be formed on the substrate 2 by holding the targets 3 of two types on the opposite surface of the target holder 4 and rotating the target holder 4 by 180 °. Although a sputtering apparatus as described above is shown, the present invention is not limited to this.

On the other hand, the ion source 5 is installed on the wall of the chamber 11 so that the ion (particle) beam 10 from the sputtering ion source 5 is obliquely incident on the target surface from between the target 3 and the substrate 2. ,further,
A trap portion 12 for trapping high-speed particles mainly reflected or scattered on the target surface is provided on the chamber wall substantially opposite to the ion source 5. The trap portion 12 is formed of a tube having a predetermined length and diameter, and has a light exit angle substantially equal to the incident angle on the chamber wall in a direction in which most high-speed particles reflected or scattered on the target surface are scattered. The louver 13 is provided at the entrance of the chamber, which is installed on the wall of the chamber including the exit trajectory of the high-speed particles. The end of the trap unit 12 is the evacuation system 1
4 and the trapped high-speed particles are indicated by arrows 1
As shown by 5, the light is reflected in the trap section 12 and sucked into the vacuum exhaust system 14. The louver 13 is provided to prevent the incoming high-speed particles from directly entering the evacuation system 14 (so as to hit the inner wall of the trap unit 12).
If the trap part 12 is configured so as not to enter the louver 4, the louver 13 is unnecessary. During the process, the inside of the chamber 1 is maintained in a vacuum state by the vacuum exhaust system 6.

FIG. 2 is a principle diagram for explaining the cascade scattering phenomenon at the time of sputtering in the ion beam sputtering apparatus, and is an enlarged view of a portion surrounded by a dashed circle A in FIG. When the high-speed ion beam 10 from the sputtering ion source 5 is incident on the sputtering target 3, the particles 10 a that have entered the inside of the sputtering target 3 gradually lose kinetic energy while colliding with atoms of a substance constituting the target 3. Eventually, it stops in the target 3. Target 3 in this process
Some of the atoms 3a that are ejected toward the surface of the target 3 jump out of the surface of the target 3. This phenomenon is called sputtering, and the ejected atoms (sputtered-out atoms) 3a adhere and deposit on the substrate 2 with kinetic energy (several electron volts) corresponding to the binding energy. This energy is sufficiently larger than the energy of evaporated particles during ordinary vacuum deposition (up to 0.1 electron volts), and the energy to bounce off atoms on the substrate 2 or to form defects (several tens of electron volts or more). Since it is not large, a high-quality film with high density should be deposited on the substrate 2.

However, as shown in FIG. 2, some of the high-speed ion beams 10 incident on the target 3 do not sufficiently enter the target 3 and are reflected or scattered on the surface thereof, and almost lose energy. Without changing the direction of exercise and jumping out. Most of such high-speed particles fly out with an exit angle almost equal to the incident angle. The reflected or scattered high-speed particles 10b have energy of about 1 kiloelectron volt to several hundred electron volts, which is the kinetic energy when they leave the ion source 5, and when they enter the substrate 2, they accumulate on the substrate 2. The film material may be sputtered again or the film surface may be roughened, thereby deteriorating the characteristics of the film. Further, when the reflected or scattered high-speed particles 10b enter the chamber inner wall or the internal mechanism, the constituent materials are sputtered, and the constituent atoms that fly out are mixed as impurities into the film formed on the substrate 2. As a result, the film quality deteriorates. In FIG. 2, reference numeral 3b denotes atoms that have collided with the particles 10a that have entered the target 3 and have moved inside the target.

In the present invention, as described above, the high-speed ion beam 10 from the ion source 5 is obliquely incident on the target surface from between the target 3 and the substrate 2. Therefore, most of the high-speed particles 10b reflected or scattered on the target surface do not scatter upward, but scatter obliquely at an emission angle similar to the incident angle. The reflected or scattered high-speed particles 10b do not fly to the substrate 2 located substantially above the target 3 in a direction different from the emission trajectory of the substrate 2.
There is no risk of deteriorating the characteristics of the film formed thereon. In addition, high-speed particles 1 reflected or scattered on the target surface
Since most of the particles 0b reach the trap portion 12 and are trapped, they do not return to the inside of the chamber again. Therefore, the atoms of the constituent material are sputtered out by these high-speed particles 10b entering the inner wall of the chamber or the internal mechanism. ,
It is possible to prevent impurities from being mixed into the film on the substrate 2 during film formation. Further, since the trap portion 12 also traps high-speed particles that directly arrive without being reflected or scattered on the target surface, and particles that are reflected or scattered by the inner wall of the chamber or an internal mechanism, the trap portion 12 is provided. In addition, the problem that these particles are reflected or scattered by the inner wall of the chamber or the internal mechanism and reach the substrate can be prevented. In addition, even with the configuration of the present invention described above, the delay in the film formation rate is insignificant, and the practical film formation rate can be maintained.

In the above embodiment, the present invention is applied to an ion beam sputtering apparatus provided with one sputtering ion source. However, the present invention can be applied to an ion beam sputtering apparatus provided with a plurality of ion sources. Needless to say, the effect of the invention can be obtained. Also,
The configuration and shape of the ion beam sputtering apparatus, and the configuration, shape, arrangement, and the like of each component are not limited to those of the embodiment, and can be variously modified and changed as needed.

[0015]

As described above, according to the present invention, since the film-forming substrate is located in a direction different from the exit trajectory of the high-speed particles reflected or scattered on the sputtering target surface, these reflections occur. Alternatively, the scattered high-speed particles do not fly to the substrate. For this reason, it is possible to prevent re-sputtering of the deposited film material due to high-speed particles entering the film being formed, roughening of the film surface, and deterioration of film quality and film characteristics such as unnecessary polycrystallization. Therefore, there is an effect that a high-quality thin film can be formed on a substrate while maintaining a practical deposition rate.

Since most of the high-speed particles reflected or scattered on the target surface are trapped in the trap portion, it is necessary to prevent these high-speed particles from entering the chamber inner wall or the internal mechanism or being reflected by them. Can be prevented. Therefore, due to the intrusion of these high-speed particles, atoms of the constituent materials of the inner wall of the chamber and the internal mechanism are sputtered out, and mixed as impurities into the film being formed on the substrate, which deteriorates the film quality and the reflected particles. Since the problem of deteriorating the film quality and film characteristics by flying to the substrate can be eliminated, there is an effect that a high-quality thin film can be formed on the substrate.

Furthermore, since the trap portion also traps high-speed particles directly arriving without being reflected or scattered on the target surface, and particles arriving after being reflected or scattered by the inner wall of the chamber or an internal mechanism, these particles are trapped by the inner wall or the inner wall of the chamber. It is also possible to eliminate the problem that the film is reflected or scattered by the internal mechanism and reaches the substrate to deteriorate the film quality and film characteristics. Therefore, there is an effect that a high-quality thin film can be formed on a substrate.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing one embodiment of an ion beam sputtering apparatus according to the present invention.

FIG. 2 is a principle diagram for explaining a cascade scattering phenomenon at the time of sputtering.

FIG. 3 is a schematic configuration diagram illustrating an example of a conventional ion beam sputtering apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Chamber 2 Film-forming board 3 Sputtering target 4 Target holder 5 Sputtering ion source 6 Vacuum exhaust system 10 Ion beam 11 Chamber 12 Trap part 13 Louver 14 Vacuum exhaust system

Claims (1)

(57) [Claims] 1. A sputtering target and a substrate for film formation are arranged opposite to each other at a predetermined interval in a chamber for forming a vacuum region for performing a process, and a high-speed ion beam from a sputtering ion source is supplied to the sputtering target. The sputtering ion source is installed on the wall surface of the chamber so as to be obliquely incident on the target surface from between the sputtering target and the film formation substrate, and on the wall surface of the chamber substantially opposite to the sputtering ion source. An ion beam sputtering apparatus, further comprising a trap unit for trapping high-speed particles reflected or scattered on the target surface.