JPH11256313A - Plasma source for compound thin film forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plasma source capable of easily controlling the inside of the vacuum chamber of a compd. thin film forming apparatus independently from the pressure of the plasma source without exposing the inside of this chamber to the atm. SOLUTION: This thin film forming apparatus has an evaporation source of a deposition material, the plasma source 6 for ejecting the plasma of a reaction gas reacting with the deposition material and a substrate formed with the thin-film of the deposition material reacting with the reaction gas in the vacuum chamber. A plasma ejection port 11 of the plasma source is provided with an adjusting means for adjusting the opening area of the ejection port. The pressure in the vacuum chamber may be maintained at a high vacuum even if the plasma source has the low vacuum by narrowing the opening area of this regulating means at the time of starting the discharge of the plasma source. The adjusting means comprises a shutter 12a which is moved along the front surface of the ejection port by a working shaft 14 and has plural openings 13 varying in the opening areas.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a plasma source applied to a compound thin film forming apparatus for forming a thin film such as an oxide film or a nitride film.

[0002]

2. Description of the Related Art Conventionally, an evaporation source for heating a film-forming substance made of a solid metal and evaporating the film-forming substance into a vacuum chamber is evacuated to a vacuum chamber evacuated. 2. Description of the Related Art There is known a compound thin film forming apparatus provided with a plasma source that is turned into plasma by exciting a reaction gas with a high frequency or the like and is jetted into the vacuum chamber, and a substrate on which a thin film of a film-forming substance reacted with the reaction gas is formed. ing. In this apparatus, a thin film of an oxide or the like is formed by supplying vapor of a film-forming substance toward the substrate and reacting the vapor with a plasma of a reactive gas on the substrate.

FIG. 1 shows an example of this plasma source. A gas inlet c for introducing a reaction gas of oxygen or nitrogen gas is provided below a crucible b made of an insulator surrounded by a metal shield plate a. And a high-frequency coil d provided around the crucible b excites the reaction gas in the crucible b to be turned into plasma, and the plasma is ejected from a spout f formed in the crucible lid e toward a substrate in a vacuum chamber. I do. The diameter of the spout f is as small as about 0.5 to 2.5 mm, and the pressure in the crucible b is maintained while maintaining a high vacuum of 10 ^-6 Torr or more in order to form a high quality thin film in the vacuum chamber. 10 ^-2 required for discharging
It can be maintained at a low vacuum of 10 ^-3 Torr.

[0004]

In the conventional plasma source described above, the spout f is provided on the crucible lid e, and once the plasma source is attached to the thin film forming apparatus, the spout f
, Ie, the opening area could not be changed. In the plasma source, the pressure in the crucible needs to be increased to about 10 ^-1 to 10 ^-2 Torr at the start of the plasma discharge as compared with that at the time of the normal discharge.
^The pressure increased to ^-3 to 10 ^-4 Torr, and there was a problem that a substrate which had been cleaned in a high vacuum was contaminated again and a high-quality thin film could not be formed. Further, since the diameter of the jet port f is constant, the pressure in the crucible b and the pressure in the vacuum chamber are uniquely determined. For example, the state of the plasma, that is, the pressure in the crucible b is kept constant, and the vacuum chamber is kept constant. It was not possible to form a thin film by greatly changing the pressure parameters in the vacuum chamber, such as controlling the pressure of the thin film. In order to adjust the pressure in the vacuum chamber independently of the pressure in the crucible, the vacuum chamber is exposed to the atmosphere, and the crucible lid e of the plasma source is placed in the crucible b.
And the nozzle f must be replaced with another one having a different area of the ejection port f, which has a disadvantage that the replacement operation is troublesome and the operation efficiency of the apparatus is deteriorated.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a plasma source capable of easily controlling the inside of a vacuum chamber of a compound thin film forming apparatus independently of the pressure of the plasma source without exposing the inside thereof to the atmosphere.

[0006]

According to the present invention, a vacuum chamber includes:
A thin film forming apparatus comprising: an evaporation source for a film forming substance; a plasma source for ejecting plasma of a reaction gas reacting with the film forming substance; and a substrate on which a thin film of the film forming substance reacted to the reaction gas is formed. In this case, the above object is achieved by providing an adjusting means for adjusting the opening area of the plasma outlet at the plasma outlet of the plasma source. The adjusting means,
It is advantageous in terms of manufacturability and durability to constitute a shutter having a plurality of openings that move along the front surface of the ejection port by the operation shaft and have different opening areas.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. In FIG. 2, reference numeral 1 denotes a vacuum chamber having a vacuum exhaust port 2 connected to a vacuum pump, and 3 denotes a vacuum chamber provided in the vacuum chamber 1. An evaporation source 5 and a plasma source 6 are arranged so that vapor of a film-forming substance and plasma of a reaction gas reach a substrate 4 detachably held on the substrate holder 3 with the plate surface facing downward. It was attached to the vacuum chamber 1. The evaporation source 5
Is a known device provided with a container to be heated therein. The vapor generated by heating the solid metal contained in the container is evaporated toward the substrate 4 and deposited on the plate surface of the substrate 4. Thus, a thin film is formed. When a plasma of a reactive gas such as oxygen or nitrogen is ejected from the plasma source 6 toward the substrate 4 during this deposition, the thin film deposited on the substrate 4 undergoes an oxidation or nitridation reaction, and an oxide film or a nitride film is formed. It becomes a film.

As shown in FIG. 3, for example, the plasma source 6 is provided with a gas inlet 8 for introducing a reaction gas such as oxygen or nitrogen gas at a lower portion, and the upper portion thereof is closed with a crucible lid 10 and is made of an insulator. A high-frequency coil 9 is provided around the crucible 7, and the reaction gas inside the crucible 7 is
The plasma is excited by the plasma and is ejected toward the substrate 4 from a plasma ejection port 11 formed in the crucible lid 10. This configuration is substantially the same as the conventional one, but as described above, the plasma source In order to eliminate the inconvenience that the substrate 4 is contaminated by increasing the pressure of 6 at the start of discharge,
An adjusting means 12 for adjusting the opening area of the jet port 11 of the plasma source 6 is provided.

As shown in FIG. 4, for example, the adjusting means 12 is configured such that a shutter 12a having three openings 13 having different areas is movable by an operating shaft 14 along the front surface of the crucible lid 10, By rotating the operating shaft 14 directly or indirectly from the outside of the vacuum chamber 1,
One opening area is controlled to the area of each opening 13. In this case, each opening 13 is formed in an area smaller than the jet port 11. The shutter 12a is constituted by a plate having no opening, and when the operating shaft 14 is turned, the ejection port 1 is formed at a side edge of the plate.
It is also possible to adopt a configuration of a variable aperture that gradually closes 1.

When the diameter of the jet port 11 is 2 mm, the diameter of the shutter 12a is 1 mm, 0.5 mm, 0.2 mm.
Is formed, and even if the inside of the vacuum chamber 1 is in a high vacuum of the order of 10 ⁻⁶ Torr, the jet port 11 is closed by the 0.5 mm opening 13 having a smaller area than the jet port. Even when the inside of the crucible 7 is set to a low vacuum of 10 ^-2 to 10 ^-3 Torr at the start of discharge, a high vacuum in the vacuum chamber is maintained, and a compound thin film can be formed on the substrate 4 without contaminating the substrate 4. did it. Prior to the start of discharge, the evaporation source 5 is operated to introduce vapor of the film forming substance into the vacuum chamber.

[0011]

As described above, according to the present invention, the plasma jet port of the plasma source of the apparatus for forming a compound thin film is provided with an adjusting means for adjusting the opening area thereof, so that the vacuum chamber is not exposed to the atmosphere. The area of the plasma outlet can be changed, the vacuum source can be maintained at a high vacuum even if the plasma source is set to a low vacuum to start discharge, and the substrate in the vacuum chamber is not contaminated, and the opening area is relatively simple. There is an effect that the adjusting means can be manufactured simply and inexpensively by adopting the structure of claim 2.

[Brief description of the drawings]

FIG. 1 is a side view of a plasma source provided in a conventional compound thin film forming apparatus.

FIG. 2 is a partially cutaway side view showing an embodiment of the present invention.

FIG. 3 is an enlarged partial cross-sectional view of a main part of the plasma source of FIG. 2;

FIG. 4 is a plan view of the crucible lid of FIG. 3;

[Explanation of symbols]

1 vacuum chamber, 2 vacuum exhaust ports, 4 substrates, 5 evaporation sources,
6 plasma source, 8 gas inlet, 9 high frequency coil,
10 crucible lid, 11 plasma outlet, 12 adjusting means, 12a shutter, 13 opening, 14 operating axis,

Claims (2)

[Claims] An evaporation source for a film-forming substance, a plasma source for ejecting plasma of a reaction gas reacting with the film-forming substance, and a thin film of the film-forming substance reacting with the reaction gas are formed in a vacuum chamber. A plasma source for a compound thin film forming apparatus, comprising: a thin film forming apparatus having a substrate; and an adjusting means for adjusting an opening area of the jet port of the plasma source. 2. The compound thin film according to claim 1, wherein said adjusting means is constituted by a shutter having a plurality of openings having different opening areas and moving along the front surface of said jet port by an operating shaft. Plasma source for production equipment.