JPH076062B2 - Sputtering device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sputtering apparatus, and more particularly to a sputtering apparatus using a microwave and a magnetic field.

Conventional technology Conventionally, a high-ionization plasma is formed using a microwave and a magnetic field, an electric field is applied to the ions in the plasma, and the target is irradiated with high-speed ions to cause a sputtering phenomenon to cause a thin film formation. Is well known.
[JAPAN JOURNAL OF APPLIED PHYSICS] Vol.23, No.
8, AUGUST, 1984, pp. L534-L536, JP-A-60-50167]
As a conventional example, FIG. 4 shows a schematic view of the apparatus. As a basic configuration, a plasma chamber 11 for generating plasma and a film forming chamber 12 for forming a thin film on the substrate 5 are provided as two chambers, and a target 13 is provided inside the film forming chamber 12 to configure the apparatus. . Such a configuration is to use the plasma chamber 11 as an ion generation source so that the generation of ions in the plasma chamber 11 and the sputtering phenomenon in the film formation chamber 12 can be controlled independently. That is, by applying a magnetic field under the electron cyclotron resonance (ECR) condition generated by the microwave and the electromagnet 7 (in the case of the microwave frequency f0 = 2.45 GHz, the magnetic field under the ECR condition B0 = 0.0875T) to the plasma chamber 11. , Form a plasma. This plasma flows out into the film forming chamber 12 through the extraction window 14. While flowing out, the target 13 having a negative potential with respect to the plasma is irradiated with the ions in the plasma to cause a sputtering phenomenon. Here, the target 13 has a right cylindrical shape or a conical shape.
Then, the sputtered target material enters the plasma and reaches the substrate 5 together with the plasma while being ionized. As a result, a compound that has been reacted and synthesized with the target substance or the substance in the plasma is formed on the substrate 5. When an aluminum oxide film, for example, is formed on the substrate 5 with such a structure, a dense film can be obtained at high speed.

However, in the above configuration, the plasma chamber for generating plasma and the chamber for sputtering are separated into two chambers, and it is necessary to transport ions. There was a point.

First, some of the ions in the high-ionization plasma formed in the plasma chamber by the microwave and the magnetic field are transported by the magnetic field or the electric field, and some of the ions are used for sputtering the target. There was a problem that it was limited by the amount of transportation.

Further, when the ions in the plasma are transported by a magnetic field or an electric field, the constituent materials of the wall surface and the deposits deposited on the wall surface due to the sputtering of the ions on the wall surface during the transportation are mixed as impurities in the film, and the film quality is deteriorated. There was a problem that caused it.

Furthermore, highly reactive particles (usually neutral particles whose lifetime is on the order of tens of nanoseconds) that are highly excited in the plasma chamber require transport in the case of a two-chamber configuration. For this reason, there is a problem that the excited particles and the ground state are attenuated by the time they reach the surface of the substrate, the excited particles cannot be used, and the film quality is deteriorated. Further, since most of such excited particles cannot be controlled by a magnetic field or an electric field because they are neutral particles, there is a problem that they collide with the wall surface of a plasma chamber or the like in a two-chamber configuration and the excited particles return to the ground state. there were.

As described above, in the two-chamber configuration of the plasma chamber and the film formation chamber, the ion source control and the film formation control including the sputtering phenomenon were independently performed. It is an object of the present invention to provide a sputtering apparatus that enables independent control of ion generation and film formation in a single chamber of a tank and enables high-speed deposition and high-quality film formation.

Means for Solving the Problems In order to solve the above problems, the present invention provides a vacuum chamber having a one-chamber configuration, a target installed in the vacuum chamber, a substrate installed in the vacuum chamber to deposit a thin film, and a vacuum. A sputtering apparatus having means for introducing microwaves into a chamber and means for applying a magnetic field inside a vacuum chamber, wherein the intensity of the magnetic field is at or above an electron cyclotron resonance condition determined by the frequency of the microwave, and the target is It is a sputtering device installed in the vicinity of a microwave introduction part in a vacuum chamber.

In the sputtering apparatus of the present invention, it is preferable that the magnetic field intensity around the target is set to the electron cyclotron resonance condition or less.

Action The present invention, as in the above-mentioned configuration, installs a target and a substrate in a vacuum chamber having a one-chamber structure, introduces a microwave into the vacuum chamber, and means for applying a magnetic field in the vacuum chamber. In a sputtering device having a magnetic field intensity higher than the electron cyclotron resonance condition determined by the frequency of the microwave, high-ionization plasma is formed, and the ions in the plasma are applied to the target installed near the microwave introduction part. Irradiation causes a sputtering phenomenon to form a thin film on the substrate.

That is, a microwave and a magnetic field are applied to the vacuum chamber of one chamber, and the magnetic field strength is set to a magnetic field strength equal to or higher than the electron cyclotron resonance condition determined by the frequency of the microwave, so that highly ionized plasma can be formed. The place where this plasma is formed is in the vicinity of the introduction part that introduces microwaves into the vacuum chamber, and since the target was installed near this microwave introduction part, most of the ions in the plasma were targeted without transporting ions. Can be irradiated. The plasma is controlled by the microwave power and the magnetic field strength, and the sputtering phenomenon is controlled by the potential applied to the target. For the above reason, even in the case of the one-chamber structure, the generation of plasma and the sputtering phenomenon can be independently controlled as in the case of the two-chamber structure, and all the generated ions can be used for the sputtering phenomenon, so that the deposition rate can be improved.

Furthermore, since the target is installed in the vacuum chamber near the microwave introduction part and ions are not transported, there is no sputtering of the wall surface due to ions, etc., and it is possible to prevent impurities from mixing into the thin film. Can be eliminated.

In addition, since the excited reactive particles also have a one-chamber structure, it is easy to reach the substrate in the excited state, and a high quality thin film can be obtained.

In the sputtering apparatus of the present invention, by setting the magnetic field strength around the target to be equal to or less than the electron cyclotron resonance condition, the magnetic field strength around the target becomes low, so that the ions in the plasma can be collected around the target. Embodiments That Allow Efficient Sputtering An embodiment of the present invention will be described with reference to FIG. 1 with reference to the drawings. FIG. 1 is a schematic view of an apparatus according to an embodiment of the present invention. In the figure, the same numbers as those in FIG. 4 are given the same numbers. Reference numeral 1 is a vacuum chamber, and 2 is a target.

Hereinafter, a microwave having a frequency f0 of 2.45 GHz is used.

As the vacuum chamber 1, a microwave circular waveguide having an inner diameter of 20 cm was used. Microwave is a circular microwave waveguide with an inner diameter of 8 cm 1
It is introduced into the vacuum chamber 1 through 0. The vacuum chamber 1 and the microwave waveguide 10 were arranged so as to have the same center. The target 2 was arranged in the vicinity where the microwave was introduced into the vacuum chamber 1, that is, in the vicinity of the inner diameter difference portion 16 between the vacuum chamber 1 and the microwave waveguide 10.

FIG. 2 shows a detailed view of the periphery of the target 2. The target 2 was placed near the inner diameter difference portion 16. As the size of the target 2, a metal having an outer diameter of 19.6 cm and an inner diameter of 8.4 cm or a conductive material was used. The target 2 and the inner diameter difference portion 16 (vacuum chamber 1) are insulated by an insulating layer. The shield 4 covers a part of the target 2 with a gap from the target 2 so that the side surface of the target 2 is not sputtered. The effective area of the target 2 to be sputtered was 220 cm ² except for the shield 4.

FIG. 3 shows the magnetic field strength distribution around the target 2. The magnetic field strength in the vicinity of the target 2 should be equal to or higher than the magnetic field intensity in the vicinity of the target 2 where the microwave is introduced into the vacuum chamber 1 and the inner diameter difference portion 16 (that is, the target 2) to the substrate 5 (the distance from the target 2 to the substrate 5 is 15 cm). Is provided, that is, the magnetic field strength of the target 2 is minimized. In addition, the magnetic field strength distribution is set so as to have a magnetic field region B18 (B0 = 0.0875T in the case of f0 = 2.45 GHz) that satisfies the ECR condition from the target 2 to the substrate 5. The magnetic field strength of the substrate 5 and the target 2 is 0.09T near the substrate 5, 0.08T near the target 2, and the position of the magnetic field strength under the ECR condition is
It was about 5 cm from target 2.

The formation of the aluminum oxide film will be described below by using the sputtering apparatus of this embodiment configured as described above.
Aluminum is used as the target 2, argon gas and oxygen gas are used as the sputtering gas, and each is 5 SCCM.
And the total pressure was 0.2 Pa. A glass substrate was used as the substrate 5. A power supply 8 was connected to the target 2 and a DC voltage of −300 V was applied to the substrate holder 6. The microwave power was 300W. Under this condition, the current flowing through the target 2 was 400 mA and the current density was ² mA / cm ² .
The value of the current density is doubled as compared with the conventional example, and the effect of minimizing the magnetic field strength near the target 2 by arranging the target 2 on the inner surface of the vacuum chamber can be seen.

Under the above conditions, the aluminum oxide film was formed at a deposition rate of 25 nm / min. This aluminum oxide film has a refractive index of 1.
It was a good quality film with a composition ratio of 76 and Al: 0 = 2: 3. Further, in the aluminum oxide film, no metal other than aluminum as impurities could be detected. This means that the effect of covering the inner surface of the vacuum chamber 1 with the target 2 can be known.

Although the magnetic field strength B0 satisfying the ECR condition was set by the electromagnet 7 in the example, the magnetic field strength distribution from the target 2 to the substrate 3 may be the minimum near the target 2, and the maximum magnetic field strength is not always ECR. The condition does not have to be satisfied. A permanent magnet other than the electromagnet may be used as the means for generating the magnetic field.

In the embodiment, the apparatus is configured by using one target 2, but a plurality of targets may be arranged.

In the embodiment, a DC power source is used as the power source 8 and a metal or a conductive material is used as the target 2. However, an AC power source or a high frequency power source other than the DC power source may be used, and the target 2 may be an oxide, a carbide, or a nitride. You may use compounds, such as a thing. For example, forming a complex oxide thin film using bismuth oxide, barium carbonate, strontium oxide, cuprous oxide, etc. as a target is included in the present invention.

In the examples, argon gas and oxygen gas were used as the sputtering gas, but any inert gas other than argon gas may be used, and in the case of forming an oxide, any gas containing oxygen other than oxygen gas may be used. Well, when forming a compound such as a carbide or a nitride other than an oxide, a gas containing nitrogen or carbon may be used.

EFFECTS OF THE INVENTION As described above, the sputtering apparatus of the present invention has a target and a substrate installed in a vacuum chamber having a single chamber, and has means for introducing microwaves and means for applying a magnetic field. In the sputter device, a magnetic field higher than the electron cyclotron resonance condition determined by the microwave frequency was applied, and a target was placed near the microwave introduction part in the vacuum chamber with a simple configuration to introduce high-ionization plasma into the microwave. Since it can be formed on the surface near the target, that is, on the surface near the target, it is possible to irradiate the target without transporting the ions in the plasma and to provide a device capable of high-speed deposition.

In addition, since the target is installed in the vicinity of the microwave introduction part in a vacuum chamber with one chamber, there is no sputtering of ions or the like on the wall surface due to transport, no contamination of impurities in the thin film, and deterioration of the film quality is prevented. effective.

Furthermore, since the excited reactive particles have a single-chamber structure, they can easily reach the substrate in the excited state, which is effective in improving the film quality.

In the sputtering apparatus of the present invention, when the magnetic field strength around the target is set to be equal to or less than the electron cyclotron resonance condition, the ions in the plasma can be collected around the target, and the sputtering apparatus can be efficiently provided. it can.

As described above, the present invention has excellent effects,
The industrial value of the present invention is high.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a sputtering apparatus according to an embodiment of the present invention,
2 (A) and 2 (B) are detailed plan views and cross-sectional views around the target of this embodiment, FIG. 3 (A) is a cross-sectional view of the main part of the apparatus of FIG. 1, and FIG. FIG. 4 is a magnetic field intensity distribution diagram of the portion (A), and FIG. 4 shows a conventional sputtering apparatus. 1 ... Vacuum tank, 2 ... Target, 5 ... Substrate, 8 ...
Power supply, 7 ... electromagnet, 14 ... drawer window.

Claims (2)

[Claims] 1. A vacuum chamber having a one-chamber structure, a target installed in the vacuum chamber, a substrate installed in the vacuum chamber for depositing a thin film, and means for introducing a microwave into the vacuum chamber. A sputtering apparatus having a means for applying a magnetic field in the vacuum chamber, wherein the intensity of the magnetic field is equal to or higher than an electron cyclotron resonance condition determined by the frequency of the microwave, and the target is the micro chamber in the vacuum chamber. A sputtering device, which is installed near the wave introducing part. 2. The sputtering apparatus according to claim 1, wherein the magnetic field intensity around the target is set to be equal to or less than the electron cyclotron resonance condition.