JPH05230627A - Vacuum deposition device - Google Patents

Abstract

PURPOSE:To decrease atoms (molecules) (remaining on a substrate) not suited for material constituting a thin film and simultaneously to easily form a thin film of uniform film thickness distribution with simple structure to prevent the contamination of a vapor deposition source due to the fall of impurities stuck on the substrate and its neighborhood. CONSTITUTION:Atoms (molecules) are vaporized by heating a vapor deposition source 2 in a vacuum deposition device 10 in the vacuum state. And the atoms (molecules) are brought into contact with each other in a space in the heat equilibrium between the vapor deposition source 2 and a filter 11 to remove impurities, causing the molecules not suited for material constituting a thin film to be decomposed into appropriate atoms (molecules). After the atoms (molecules) are passed through holes 12, 12, 12 of the filter 11, they become vaporized beams 13 to collide with the substrate 3. And the atoms (molecules) remain on the substrate 3 and bonded with each other to form a thin film.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum vapor deposition apparatus for forming a thin film on a substrate by a vapor deposition method in a vacuum container.

[0002]

2. Description of the Related Art Conventionally, in a vacuum vapor deposition apparatus, a vapor deposition source is provided in a vacuum container, a substrate is placed directly on it, and a thin film is formed on the substrate by a vapor deposition method.

FIG. 2 shows an example of a conventional vacuum vapor deposition apparatus.
In this figure, this vacuum vapor deposition apparatus 1 is provided with a vapor deposition source 2, and a substrate 3 is placed directly above the vapor deposition source 2. Next, a process of forming a thin film on the substrate 3 by the vapor deposition method in the vacuum vapor deposition apparatus 1 will be described.

First, the evaporation source 2 is heated to evaporate atoms (molecules) from the evaporation source 2. These atoms (molecules) move through the space inside the vacuum vapor deposition apparatus 1 in a vacuum state to the evaporation beam 4
And flies toward the substrate 3. At this time, the evaporation beam 4 collides with the substrate 3 while expanding at a certain angle θ in the space between the vapor deposition source 2 and the substrate 3. And
Atoms (molecules) forming the evaporation beam 4 remain on the surface of the substrate 3 and these atoms (molecules) bond to each other to form a thin film.

In such a vacuum vapor deposition apparatus, the thin film formed is required to have a uniform film thickness distribution. As a method for improving the film thickness distribution, for example, as shown in JP-A-62-93368, a method of devising the shape of a vapor deposition source container, a method of providing a plurality of vapor deposition sources, and the like are known. ..

[0006]

By the way, the atoms (molecules) constituting the vapor deposition source 2 of the vacuum vapor deposition apparatus 1 described above include atoms (molecules) not suitable as a substance constituting the thin film. There was something. For example, there are impurities and the like mixed in the vapor deposition source. When the vapor deposition source 2 is heated, these impurities often evaporate while being bonded to atoms (molecules) suitable as a substance forming the thin film. In addition, molecules having a molecular structure that is not suitable as a substance forming the thin film may evaporate.

When a thin film is formed on the substrate 3 by these impurities or molecules having a molecular structure not suitable for the thin film,
There was a problem that a desired thin film could not be obtained.

Further, the above-mentioned single vapor deposition source 2 has an advantage that the structure and the control are simple, but the thin film formed on the substrate 3 becomes centrally symmetric and a thin film having a uniform film thickness distribution can be obtained. There was a problem that I could not. On the other hand, in the case of providing a plurality of vapor deposition sources, there is a problem that control of each vapor deposition source becomes complicated.

Further, since the substrate 3 is placed right above the vapor deposition source 2, when the pressure in the container is returned from vacuum to normal pressure, the impurities adhering to the substrate 3 and the surroundings due to the change in pressure will be the vapor deposition source. It sometimes dropped to 2. As a result, there arises a problem that the vapor deposition source 2 is contaminated with impurities.

The present invention has been made in view of the above-mentioned circumstances, and it removes impurities having a simple structure and molecules having a molecular structure unsuitable as a substance constituting a thin film, and impurities attached to the substrate or its periphery are removed. It is an object of the present invention to provide a vacuum vapor deposition device that prevents the vapor deposition source from being contaminated due to a drop of a film or the like and vapor deposits a thin film having a uniform film thickness distribution.

[0011]

In order to solve the above-mentioned problems, in the present invention, a vapor deposition source is provided in a vacuum container, and a substrate is placed directly on it, and the vapor deposition source is smaller than the substrate, Further, in the vacuum vapor deposition apparatus in which the vapor deposition source and the substrate are positioned at a distance approximately the same as the size of the substrate, a plurality of penetrating holes provided between the vapor deposition source and the substrate so as not to be directly above the vapor deposition source. It is characterized in that a filter having holes is provided.

[0012]

According to the present invention, since the filter having the plurality of through holes is provided between the vapor deposition source 2 and the substrate 3 of the vacuum vapor deposition apparatus, a thermal equilibrium state is established between the vapor deposition source 2 and the filter. In a space, atoms (molecules) collide with each other. Then, molecules that are not suitable as a substance forming the thin film are decomposed into suitable atoms (molecules), and these atoms (molecules) pass through the through holes and collide with the substrate 3 as an evaporation beam.
Then, these atoms (molecules) remain on the substrate 3 and are bonded to each other to form a thin film.

[0013]

Embodiments of the present invention will now be described with reference to the drawings. 1 (a) and 1 (b) are diagrams showing the configuration of an embodiment of the present invention. In these figures, parts corresponding to those in FIG. 2 described above are designated by the same reference numerals, and description thereof will be omitted.

FIG. 1A is a sectional view showing the inside of a vacuum vapor deposition apparatus 10 showing the structure of an embodiment of the present invention. In this figure, a filter 11 is provided between the vapor deposition source 2 and the substrate 3.
Is provided, which is different from FIG. Figure 1
(B) shows a top view of the filter. In this figure, the filter 11 has a plurality of through holes 12, 12, ...
, 12 are provided so as to avoid immediately above the vapor deposition source 2.

Next, the process of forming a thin film on the substrate 3 by the vapor deposition method in the above structure will be described.

First, the evaporation source 2 is heated to evaporate atoms (molecules) from the evaporation source 2. At this time, as described above, the vaporized atoms (molecules) may include molecules, impurities, and the like that are not suitable as a substance forming the thin film. However, in the space between the vapor deposition source 2 and the filter 11, it is considered to be in a thermal equilibrium state, and atoms (molecules) collide with each other and also collide with the wall. As a result, the impurities bonded to the atoms (molecules) suitable as the substance forming the thin film are more likely to be released from the atoms (molecules).

Also, molecules having a molecular structure that is not suitable as a substance forming the thin film are more likely to be separated from each other in this space due to the collision of the atoms (molecules) described above.

For example, when GaAs is vapor-deposited on the substrate 3, the atoms (molecules) vaporized from the vapor deposition source 2 are mainly A
It is considered that there are three types of atoms (molecules) of s, As ₂ , and As ₄ . Among them, As ₄ is not so preferable as a molecule for vapor deposition. In the space between the vapor deposition source 2 and the filter 11, As ₄ is more likely to be decomposed into As or As ₂ .

As described above, at this stage, the filter 11
By the action of the thermal band filter of, it is possible to remove impurities with different kinetic energies, and to use the atoms (molecules) that are not suitable as the substance that constitutes the thin film.
Can be decomposed into

Further, these atoms (molecules) pass through the through holes 12, 12, ... In the space between the filter 11 and the substrate 3, the density of atoms (molecules) per unit volume is reduced, so that atoms (molecules) of each other are reduced.
Are exercising without much collision. Therefore, these atoms (molecules) become the evaporation beam 13 and fly toward the substrate 3.

Then, the evaporation beam 13 collides with the substrate 3, and these atoms (molecules) remain on the substrate 3 and bond with each other, forming a thin film. At this time, the evaporation beam 13 collides with the substrate 3 while expanding at a certain angle θ ′ between the filter 11 and the substrate 3.
The relationship of θ ′> θ is established between θ ′ and θ, and the evaporation beam can be expanded more than before. As a result, as in the case where a plurality of evaporation sources are provided, the formed thin film does not have central symmetry and the film thickness distribution becomes uniform.

Further, even if impurities adhering to the substrate drop due to a change in pressure when the pressure in the container is returned from vacuum to normal pressure, the impurities are deposited by the vapor deposition source 2 due to the structure of the filter 11 as described above. It will not be mixed in. As a result, the vapor deposition source 2 can avoid contamination by impurities.

The number, size, shape, etc. of the through holes provided in the filter 11 described above are determined by the compositional components of vapor deposition,
It can be appropriately changed depending on the film thickness of the thin film to be formed.

[0024]

As described above, according to the present invention, the filter having the plurality of through holes provided so as to avoid the position directly above the vapor deposition source is provided between the vapor deposition source and the substrate. It is possible to reduce the number of atoms (molecules) that are not suitable as a substance forming the thin film (remain on the substrate), and to form a thin film having a uniform film thickness distribution on the substrate.
Further, there is an advantage that the contamination of the vapor deposition source can be prevented.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a vacuum vapor deposition device showing a configuration of an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing one configuration of a conventional vacuum vapor deposition device.

[Explanation of symbols]

2 ... Deposition source, 3 ... Substrate, 10 ... Vacuum deposition apparatus, 11 ... Filter, 12 ... Through hole, 13 ...
Evaporation beam

Claims (1)

[Claims] 1. A vapor deposition source is provided in a vacuum container, and a substrate is placed directly on the vapor deposition source. The vapor deposition source is smaller than the substrate, and the vapor deposition source and the substrate have the same size as the substrate. In a vacuum vapor deposition apparatus positioned at a certain interval, a vacuum vapor deposition apparatus characterized by providing a filter having a plurality of through holes provided between the vapor deposition source and the substrate so as to avoid immediately above the vapor deposition source. apparatus.