JP2003193232A - Ion beam sputtering apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the efficiency of utilization of a target. <P>SOLUTION: Plasma is generated in a plasma generation chamber 28 of an ion source 10, and the ions are drawn out of the plasma by an ion drawing electrode 22, and irradiated toward the target 16 as an ion beam 42. When the ion beam 42 is electrically neutralized by a microwave neutralizer 12, the electric potential of a strip-like electrode 44 is set to be the negative potential with respect to a sputter chamber 14, and Ar ions in the neutralizing plasma 52 are collected by the strip-like electrode 44. Electrons equivalent to the collected Ar ion charges are fed to the ion beam 42 to neutralize the ion beam 42, and the degree of neutralization is controlled by the power of the microwave. As a result, divergence and convergence of the ion beam 42 are controlled, and a sputtering area of the target 16 is controlled thereby. <P>COPYRIGHT: (C)2003,JPO

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, and more particularly to an ion beam sputtering apparatus suitable for forming an optical thin film or a magnetic thin film on a film forming target such as a substrate.

[0002]

2. Description of the Related Art Ion beam sputtering is used to form an insulating film on a substrate such as a silicon wafer. The ion beam sputtering method has an advantage that a high-quality thin film can be formed because a film can be formed in a high vacuum atmosphere.

As an ion beam sputtering apparatus, for example, as described in Japanese Patent Application Laid-Open No. 7-157876, a sputter which accommodates a target to be sputtered by an ion beam and a substrate holder holding a substrate on which a thin film is to be formed. It is known that the chamber is provided with an ion source for extracting ions from the plasma in the plasma chamber and irradiating an ion beam toward a target in the sputtering chamber, and a neutralizer for neutralizing the ion beam extracted from the ion source. Has been. In this type of ion beam sputtering device,
When an insulator is used as the target and the insulator is sputtered with an ion beam to form a film on the substrate, a neutralizer is used to electrically neutralize the ion beam and prevent the substrate from being charged. Has been adopted.

[0004]

In the conventional ion beam sputtering apparatus, since the thermoelectrons supplied from the filament are used for neutralizing the ion beam, the life of the neutralizer is shortened. That is, because the filament is placed in an atmosphere that is directly exposed to the ion beam,
The life of the filament is as short as several tens of hours, which causes the maintenance cycle to be shortened. Incidentally, JP-A-8-29
As described in Japanese Patent No. 6069, it is also possible to employ a neutralizer using microwaves without using a filament. However, JP-A-8-2960
Since the neutralizer described in Japanese Patent Publication No. 69 is used in a milling device, even if the neutralizer is used as it is in an ion beam sputtering device, it is not sufficient to improve the utilization efficiency of the target.

That is, in the ion beam sputtering apparatus, it is difficult to install the target and the substrate close to each other due to the apparatus configuration, so that the utilization efficiency of the target is reduced as compared with the normal bipolar sputtering.

An object of the present invention is to provide an ion beam sputtering apparatus which can improve the utilization efficiency of a target.

[0007]

In order to solve the above-mentioned problems, the present invention provides a sputtering target which is a base material, a sputtering chamber for accommodating a film-forming target, and a plasma generation chamber for generating plasma. An ion source having an ion extraction electrode for extracting ions from the plasma and irradiating an ion beam toward a sputtering target in the sputtering chamber, and a neutralizer for electrically neutralizing the ion beam extracted from the ion extraction electrode. The neutralizer includes a strip electrode that forms an ion beam transmission path that connects the ion source and the sputtering chamber, and a magnetic field in the ion beam transmission path and a microwave in the magnetic field. And a plasma generating means for neutralizing the plasma to introduce the neutralizing plasma. Te is obtained by constituting the ion beam sputtering apparatus was formed by a negative potential.

In constructing the ion beam sputtering apparatus, the following elements can be added.

(1) A microwave control means for controlling the electric power of the microwave introduced into the magnetic field is provided.

(2) The neutralizer functions as an ion beam control means for controlling the divergence of the ion beam in the ion beam transmission path due to space charges.

According to the above-mentioned means, when the ion beam from the ion source is irradiated toward the sputtering target in the sputtering chamber, the strip-shaped electrode forming the ion beam transmission line connecting the ion source and the sputtering chamber is formed. Neutralization plasma is generated, the ion beam is neutralized by the neutralization plasma, and the strip electrode is set to a negative potential with respect to the sputtering chamber. It can be collected, and the same amount of electrons as the collected ionic charge can be uniformly supplied toward the ion beam. In this case, by controlling the electric power of the microwave introduced into the magnetic field, that is, by controlling the divergence / convergence of the ion beam in the ion beam transmission path due to the space charge, the neutralization plasma moves toward the ion beam. The amount of supplied electrons can be changed. Therefore, by controlling the divergence / convergence of the ion beam,
Since the sputtered region of the sputtering target can be controlled, the utilization efficiency of the target can be improved.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a vertical sectional view of an ion beam sputtering apparatus showing an embodiment of the present invention. In FIG. 1, the ion beam sputtering apparatus includes an ion source 10, a microwave neutralizer 12, and a sputtering chamber 14, and a sputtering target (hereinafter referred to as a target) serving as a base material is provided in the sputtering chamber 14. 16), a substrate holder 20 for holding a substrate 18 as a film formation target is housed.

The ion source 10 is formed in a substantially bowl shape, an ion extracting electrode 22 is arranged on the opening side, a gas introducing port 24 is formed on the wall on the closed portion side, and a filament 26 is fixed. , The space is the plasma generation chamber 28
Is formed as. The gas inlet 24 is connected to a storage container (not shown) that stores Ar gas, and the filament 26 is connected to a DC power supply 30. Ar gas is introduced into the plasma generation chamber 28 from the gas inlet 24, and the introduced Ar gas is turned into plasma by thermoelectrons from the filament 26. In this case, in order to confine the plasma in the plasma generation chamber 28, a plurality of permanent magnets 32 are arranged on the outer peripheral wall surface of the ion source 10, and each permanent magnet 32 causes a cusp magnetic field in the plasma generation chamber 28. Are formed.

The ion extracting electrode 22 is an accelerating electrode 22a,
It is composed of an ion extraction electrode 22b and a bias electrode 22c, and each electrode is provided with a plurality of holes for passing the ions as an ion beam when the ions are extracted from the plasma in the plasma generation chamber 28. ing. The acceleration electrode 22a is connected to the positive terminal of the DC power supply 34, and the ion extraction electrode 22b is connected to the negative terminal of the DC power supply 36. The wall surface of the ion source 10 is connected to the negative terminal of the DC power source 38 and set to a negative potential. The bias electrode 22c is connected to the wall surface of the microwave neutralizer 12 that is insulated from the wall surface of the ion source 10, and this wall surface is connected to the negative terminal of the DC power supply 40. Therefore, the bias electrode 22c is set to a negative potential with respect to the sputtering chamber 14. When a voltage from the DC power supplies 34, 36, 40 is applied to each electrode of the ion extraction electrode 22, ions are extracted from the plasma in the plasma generation chamber 28 to the outside of the plasma generation chamber 28, and the extracted ions are ion beam. 42 as the sputtering chamber 14
The target 16 inside is irradiated. Further, the ion beam 42 extracted from the ion source 10 is electrically neutralized while passing through the microwave neutralizer 12.

The microwave neutralizer 12 is provided with a strip electrode 44 forming an ion beam transmission path connecting the ion source 10 and the sputtering chamber 14, and a microwave introduction port 46 is formed in the middle of the strip electrode 44. Has been done. The microwave introduction port 46 is connected to a microwave generator (not shown) via a waveguide 48, and a microwave of 2.45 GHz is generated from the microwave generator in the strip electrode 44 in the waveguide 4.
8. It is adapted to be introduced through the microwave introduction port 46.

On the outer peripheral side of the strip electrode 44, as shown in FIG. 2, a plurality of permanent magnets 50 are arranged in a ring shape so as to be separated on both sides of the waveguide 48 with the waveguide 48 interposed therebetween.
4 has a ring-shaped permanent magnet 50,
An electron cyclotron resonance (ECR) magnetic field is created. 2.45GH in this electron cyclotron resonance magnetic field
When the microwave of z is introduced, the introduced microwave resonates with electrons in the electron cyclotron resonance magnetic field and is absorbed, Ar gas is ionized, and ring-shaped plasma 52 for neutralization is formed. It In this case, the strip electrode 44
Is connected to the negative terminal of the DC power source 40 and has a negative potential, Ar ions in the neutralizing plasma 52 are collected by the strip electrode 44, and the same amount of electrons as the collected ionic charges are ionized. The ion beam 42 supplied to the beam 42 and containing Ar + is neutralized. Since the neutralized ion beam 42 is not charged, the beam does not diverge due to the space charge and is more focused. In this case, the divergence / convergence of the neutralized ion beam 42 can be controlled depending on the degree of neutralization.

When controlling the neutralization of the ion beam 42, the degree of neutralization can be controlled by controlling the electric power of the microwave introduced into the strip electrode 44. That is, by controlling the output power of the microwave generator connected to the microwave neutralizer 12, the power of the microwave introduced into the ECR magnetic field can be controlled. It will function as a control means. In this case, the microwave neutralizer 12 functions as an ion beam control means for controlling the divergence / convergence of the ion beam 42 in the strip electrode 44 due to the space charge.

On the other hand, the target 16 is the ion beam 4
When the target 16 is irradiated with the ion beam 42, the sputtered particles are ejected from the target 16 by the sputtering by the ion beam 42 when the target 16 is irradiated with the ion beam 42. , The sputtered particles are deposited on the substrate 18,
A thin film such as SiO ₂ can be formed on the substrate 18.

The sputtering chamber 14 is connected to an evacuation device (not shown), and sputtering is performed while the inside of the sputtering chamber 14 is kept in vacuum.

Here, the distance between the ion extracting electrode 22 and the target 16 is 350 mm, and the potential of the strip electrode 44 is -1.
When sputtering was performed at 2 V, microwave output of 100 W, and microwave power of 0 V, the results shown in FIG. 3 were obtained.

That is, the ion beam 42 extracted from the ion source 10 is neutralized with a microwave of 100 W and the neutralized ion beam 42 is applied to the target 16 and the ion beam extracted from the ion source 10. Four
Ion beam 42 without neutralizing 2
This is a measurement of the sputtering amount of the target when the target 16 was irradiated with.

From FIG. 3, when the ion beam 42 is neutralized by using a microwave of 100 W, the ion beam 4
It can be seen that the amount of spatter is large and the sputtered particles are distributed at positions where the distance from the center of the target 16 is short as compared with the case where 2 is not neutralized, and as a result, the divergence of the ion beam 42 is suppressed.

As described above, by controlling the microwave power, that is, by controlling the divergence / convergence of the ion beam 42, the sputtered region of the target 16 can be controlled, and the utilization efficiency of the target 16 can be controlled. Can be improved.

Further, when the ion beam 42 is neutralized, since the neutralization is not performed in the region directly exposed to the ion beam 42, the maintenance cycle for the microwave neutralizer 12 can be extended.

[0025]

As described above, according to the present invention,
By controlling the divergence / convergence of the ion beam, the sputtered region of the sputtering target can be controlled, so that the utilization efficiency of the target can be improved.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an ion beam sputtering apparatus showing an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of a main part of a microwave neutralizer.

FIG. 3 is a characteristic diagram for explaining the relationship between microwave power and beam profile.

[Explanation of symbols]

10 Ion source 12 Microwave neutralizer 14 Sputtering room 16 targets 18 substrates 20 substrate holder 22 Ion extraction electrode 26 filament 28 Plasma generation chamber 42 ion beam 44 band electrode

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Katsunori Nakajima             1-1-1 Kokubuncho, Hitachi-shi, Ibaraki Stock             Hitachi High-Technologies Corporation Design / Manufacturing             Kokubu Business Office F-term (reference) 4K029 DC37 EA09

Claims (3)

[Claims] 1. A sputtering chamber for accommodating a sputtering target and a film formation target as a base material, plasma is generated in the plasma generation chamber, and ions are extracted from the plasma in the plasma chamber toward the sputtering target in the sputtering chamber. An ion source having an ion extraction electrode for irradiating an ion beam, and a neutralizer for electrically neutralizing the ion beam extracted from the ion extraction electrode are provided, and the neutralizer includes the ion source and the sputter. A strip electrode that forms an ion beam transmission line connecting the chamber and a neutralizing plasma generating means that forms a magnetic field in the ion beam transmission line and introduces microwaves into the magnetic field to generate plasma for neutralization. And an ion beam sputtering apparatus in which the strip electrode has a negative potential with respect to the sputtering chamber. 2. The ion beam sputtering apparatus according to claim 1, further comprising a microwave control means for controlling the electric power of the microwave introduced into the magnetic field. 3. The ion beam sputtering apparatus according to claim 1, wherein the neutralizer functions as an ion beam control unit that controls divergence of the ion beam in the ion beam transmission path due to space charges. An ion beam sputtering device characterized by: