JPH03146661A - Thin film forming device - Google Patents

Abstract

PURPOSE:To allow dealing with the formation of films on long-sized and large- area substrates at a high speed while stabilizing the generation of plasma by constituting the cavity wall of a microwave cavity resonator so as to include the wall of the plasma. CONSTITUTION:The inside of a vacuum chamber 8 is evacuated and gaseous Ar is introduced therein. The plasma P is generated when microwaves are introduced into a waveguide tube 3. The plasma P is converged by a permanent magnet 12 and is increased in density. The plasma wall 13 is formed by the converged plasma P and the microwave cavity resonator 14 having a square cavity sectional shape is constituted of the U-shaped wall 3a of the waveguide tube 3 and the plasma wall 13. The permanent magnet 12 functions as a magnetic field means. Since the plasma wall 13 is commonly used as the plasma P for sputtering, the organical coupling of the microwaves and the plasma P is maintained and the generation of the plasma P is stabilized.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a thin film forming apparatus used in a vacuum apparatus, a film forming apparatus, a surface treatment apparatus, etc. The present invention relates to a thin film forming apparatus using sputtering.

(Prior Art) Thin film forming apparatuses are widely used in the fields of semiconductors, optical disks, optical parts, electronic parts, etc. Thin film forming apparatuses that use sputtering include bipolar and three-pole sputtering apparatuses and magnetron sputtering apparatuses. etc. are known. Two-pole and three-pole sputtering apparatuses have a slow film-forming rate and are not suitable as production equipment, so magnetron sputtering apparatuses, which have a fast film-forming rate, are often used at production sites.

However, in magnetron sputtering equipment, the film being deposited is bombarded by ions in the plasma (mainly Ar ions), which may shift the film composition or damage the film or substrate. The ionization of gases and particles in the plasma is insufficient, and from the viewpoint of reactivity, the activity is insufficient, and in order to obtain oxides and nitrides,
It is necessary to heat the substrate to 500-800'C.

On the other hand, as a thin film forming apparatus that eliminates the above-mentioned problems and enables high-speed film formation, an apparatus that increases plasma density and stabilizes plasma generation even under low gas pressure has been proposed. The one described in JP-A No. 63-96267 is known. This device has a plasma chamber shaped like a microwave resonator, a pair of sputter targets facing each other in the plasma chamber, and an electromagnet that forms a mirror magnetic field that generates magnetic flux perpendicular to the plane of these targets. The sample substrate is placed parallel to the magnetic field.

In addition, as a device similar to the above-mentioned thin film forming apparatus, rH
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The one described in Kyo (1989) is known. In this device, a ring-shaped target is provided in place of one of a pair of targets facing each other, and the sample substrate is arranged perpendicular to the magnetic field.

On the other hand, as a thin film forming apparatus having a configuration different from the above-mentioned two examples, for example, the one described in Japanese Patent Laid-Open No. 62-294181 is known. In this method, a microwave resonator is constructed in the atmosphere, a microwave-transparent window is provided on the wall of the resonator, and a substrate is placed closely or very close to the window to form a film. The wall of the waveguide is constructed using the electricity-conducting property of plasma.

(Problems to be Solved by the Invention) However, with thin film forming apparatuses such as the three examples above, for the reasons mentioned above, it is difficult to form films on large substrates or long substrates, and plasma There was a problem that the generation of

That is, in the case of the thin film forming apparatus of the previous two examples, although it can be applied to round substrates such as silicon wafers, it is extremely difficult to support film formation on large substrates or long substrates.

In addition, the thin film forming apparatus described in the last example can handle long substrates, etc., but when forming an electrically conductive film on the substrate, the microwave wall current flows through the film, causing plasma generation. cause trouble. In extreme cases, the substrate may be destroyed by the heating caused by the current. Further, it cannot be applied to sputtering.

(Objective of the Invention) Therefore, the present invention makes it possible to form a long, large-area plasma while stably generating plasma by configuring the cavity wall of a microwave cavity resonator to include a plasma wall. Therefore, it is an object of the present invention to provide a thin film forming apparatus capable of high-speed film formation on long, large-area substrates.

(Structure of the Invention) In order to achieve the above object, a thin film forming apparatus according to the present invention is a thin film forming apparatus that forms a thin film on a sample substrate using plasma sputtering. , a magnetic field generating means for generating a magnetic field and converging the plasma using the magnetic field to form a plasma wall, the cavity wall of the microwave cavity resonator comprising a plasma wall. Furthermore, the magnetic field generating means may generate a magnetic field with a strength greater than the electron cyclotron resonance magnetic field, and the microwave cavity resonator may have a rectangular cavity cross-sectional shape. .

Hereinafter, the present invention will be specifically explained based on examples.

FIG. 1.2 is a diagram showing a first embodiment of a thin film forming apparatus according to the present invention.

In FIG. 1.2, numeral 1 is a thin film forming apparatus according to the present invention, and the thin film forming apparatus 1 is an apparatus that forms a thin film on a sample substrate 2 by using sputtering with a plasma P having a high density. That is, the thin film forming apparatus 1 sputters a sputter target NO, which will be described later, to which a negative voltage is applied, using ions in a high-density plasma P, and diffuses sputter particles from the sputter target 10 to form a sample substrate. A film is formed on 2 at high speed.

Next, the configuration of the thin film forming apparatus 1 will be explained in detail.

3 is a waveguide for introducing microwaves, and the waveguide 3 is provided with a microwave introduction window 4 and a vacuum window 5 for terminating the resonator. Both ends of the waveguide 3 having the microwave introduction window 4 and the vacuum window 5 are bent at right angles to the center. Further, the waveguide 3 is provided with a reflecting plate 6 for forming a resonator and a movable metal plate 7 serving as a terminal end of the resonator, and the movable metal vi7 is movable in the vertical direction in FIG. By moving the movable metal plate 7, the reflection of microwaves can be adjusted to the minimum. The waveguide 3 has a U-shaped portion 3a opening downward in FIG. 2 at its center, and the U-shaped portion 3a extends long in the left-right direction in FIG. The above-mentioned opening of the waveguide 3 communicates with a vacuum container 8', and the vacuum container 8 is evacuated by a vacuum evacuation device (not shown). On the other hand, Ar gas as a discharge gas is introduced into the vacuum container 8 via a mass flow controller and a gas system (none of which are shown), and the aforementioned sample substrate 2 is placed inside the vacuum container 8. It is supported by a provided holder 9.

A pair of sputter targets 10 facing each other are attached to a pair of opposing walls near the passage of the waveguide 3 with the vacuum vessel 8, and the sputter targets 10 are arranged along the waveguide 3 as shown in FIG. It extends long in the left and right direction.

A negative voltage is applied to each sputter target 10 by a DC power supply 11 . A permanent magnet 12 is provided outside the sputter target 10 across the tube wall of the waveguide 3, and the permanent magnet 12 also extends long along the waveguide 3 like the sputter target 10. . Further, the permanent magnet 12 generates a magnetic field stronger than the electron cyclotron resonance magnetic field.

Here, after evacuating the vacuum vessel 8 to about 10-' Torr, Ar gas is introduced, and microwaves are introduced into the waveguide 3 at a vacuum level of about 10-' Torr, resulting in plasma P
is generated, and the plasma P is transferred to the first magnet by the permanent magnet 12.
As shown in the figure, it is converged and densified. At the same time, the plasma wall 13 (
A microwave cavity resonator 14 having a rectangular cavity cross section is formed by the U-shaped portion 3a of the waveguide 3 and the plasma wall 13. That is, the permanent magnet 12 generates a magnetic field, and the magnetic field converges the plasma P so that the plasma wall 13
It has the function of a magnetic field means to form a magnetic field. Further, the cavity wall of the microwave cavity resonator 14 is configured to include the plasma wall 13.

According to the above configuration, the following effects can be obtained.

That is, a part of the cavity wall of the microwave cavity resonator 14 is constituted by the plasma wall 13, and since the plasma wall 13 also serves as the plasma P for sputtering, organic coupling between the microwave and the plasma P is achieved. can be reliably maintained, and the generation of plasma P can be stabilized. In particular, in conventional thin film forming apparatuses in which microwaves and plasma are separated and coupled using quartz glass, etc., the bond is broken due to metal deposition, but this example eliminates this problem. It can also be used for film formation. A long, large-area plasma P can be generated along the microwave cavity 14, and can be used for film formation that requires a long, large-area film formation region, such as a long substrate or a large substrate. It can support high-speed film formation.

By generating an electron cyclotron resonance magnetic field by the permanent magnet 12, energy can be efficiently given to electrons.

Since the cross section of the cavity of the microwave cavity resonator 14 is made into a rectangular shape, and the negative side is constituted by the plasma wall 13,
- It is possible to cope with cases where a large area is required for layer formation, and it becomes possible to form a film over a large area at high speed.

Since the pair of sputter targets 10 are arranged to face each other, γ electrons generated from the surfaces of the sputter targets 10 can be effectively utilized.

Since the γ electrons generated from the sputter target 10 can be confined by the magnetic field of the permanent magnet 12, ionization efficiency can be improved.

Although the wavelength of microwaves in a vacuum and the wavelength in plasma are different, the microwaves can be tuned by moving the movable metal plate 7, so it is easy to change the wavelength of microwaves when plasma is generated. can correspond to Furthermore, since the movable metal plate 7 is provided outside the vacuum region, its movable structure can be simplified.

Since the waveguide 3 is bent at a right angle between the U-shaped portion 3a and the microwave introduction window 4 and the vacuum window 5,
It is possible to prevent high-speed particles diffused from the sputter target 10 from directly colliding with both windows 4.5, and to prevent the particles from adhering to both windows 4.5. Therefore, reduction in microwave transmission can be prevented. Furthermore, both windows 4.5 can be prevented from being damaged, and the vacuum can be prevented from being impaired.

If the holder 9 is moved in the direction of arrow A in FIG. 1, even larger substrates can be formed at higher speeds.

A film can be formed by reactive sputtering by mixing oxygen gas or nitrogen gas into the introduced Ar gas, and oxynitrides can also be formed by mixing various gases.

FIG. 3 is a diagram showing a second embodiment of the thin film forming apparatus according to the present invention. In FIG. 3, the same components as those shown in FIGS. 1 and 2 are designated by the same reference numerals and will be explained.

In FIG. 3, a sputter target 21 and permanent magnets 22 and 23 are provided on the upper side of the U-shaped portion 3a of the waveguide 3, and the sputter target 21 is provided with a DC power source 22, 23.
4 applies a negative voltage. That is, sputter targets and permanent magnets are arranged on all three sides of the U-shaped portion 3a of the IT tube 3. According to such a configuration, the plasma P is converged as shown in FIG.
．． 25, 26 and 27 are formed. Plasma walls 13, 25, 26 and 27 thus constitute a microwave cavity 28. In this case, in addition to the effects of the first embodiment described above, it is possible to construct an apparatus in which the inner surface of the waveguide 3 is not sputtered.

(Effects) According to the present invention, since the cavity wall of the microwave cavity resonator is configured to include a plasma wall, it is possible to form a long, large-area plasma while stably generating plasma. It is possible to form films on long, large-area substrates at high speed.

[Brief explanation of the drawing]

1.2 is a diagram showing a first embodiment of the thin film forming apparatus according to the present invention, in which FIG. 1 is a sectional view thereof, FIG. 2 is a sectional view taken along the line X-X in FIG. The figure is a sectional view of a main part of a second embodiment of the thin film forming apparatus according to the present invention. 2... Sample substrate, 12... Permanent magnet (magnetic field generating means), 13...
...Plasma wall (plasma wall), 14...
・Microwave cavity resonator.

Claims (3)

[Claims] (1) A thin film forming apparatus that forms a thin film on a sample substrate using sputtering using plasma includes a microwave cavity resonator that introduces microwaves, and a microwave cavity that generates a magnetic field and focuses the plasma using the magnetic field. a magnetic field generating means for forming a plasma wall, the cavity wall of the microwave cavity resonator comprising a plasma wall. (2) The thin film forming apparatus according to claim 1, wherein the magnetic field generating means generates a magnetic field with a strength greater than an electron cyclotron resonance magnetic field. (3) The thin film forming apparatus according to claim 1 or 2, wherein the microwave cavity resonator has a rectangular cavity cross-sectional shape.