JPS63179060A - Device for forming thin film - Google Patents

Abstract

PURPOSE:To obtain a device for forming a thin film capable of forming the homogeneous thin film in a range over large area by providing a couple of electrodes for uniformizing the distribution of ionic current density on a base plate between a vapor generating source and an ionizing means. CONSTITUTION:A couple of electrodes 23, 24 are provided between a vapor generating source 9 and an ionizing means 13 arranged in a vacuum tank 1. The clusters 8 of a material 5 to be deposited by evaporation are formed in the vacuum tank 1 similarly as a conventional device. Ionic current drawn out by the electric field formed with an acceleration electrode 15 is uniformly distributed for the radial direction of a base plate 16. Further penetration is made in the ionization region of the clusters 8 by means of the electric field formed with electrodes 23, 24 and the ionization region is made small in the central part of the base plate 16 wherein the clusters 8 are assembled. In other words, centralization of the distribution of ionic current density to the central part of the base plate 16 is eliminated and thereby a homogeneous thin film can be formed in a range over a large area.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field 1] The present invention relates to a thin film forming apparatus, and particularly to a thin film forming apparatus that forms a high quality thin film by vapor deposition using a cluster ion beam deposition method (ICB method).

[Prior Art] Conventionally, high quality thin films such as optical thin films, magnetic films, and insulating films have been formed by the ICB method.

FIG. 7 is a schematic configuration diagram schematically showing a conventional thin film forming apparatus disclosed in, for example, Japanese Patent Publication No. 54-9592.
In the figure, (1) is a vacuum chamber maintained at a predetermined degree of vacuum;
(2) is a vacuum evacuation system that adjusts the degree of vacuum in this vacuum chamber (1), (3) is a tight funnel-shaped crucible installed at the bottom of the vacuum chamber (1), and (4) is this crucible (3). ), (5) is a vapor deposition substance filled in the crucible (3), (6) is a heating filament that heats the crucible (3), and (7) is a heating filament for heating the crucible (3). Heat shield plate that blocks heat from filament (6), (8) is crucible (3)
A cluster (massive atomic group) formed by ejecting vapor of the vapor deposition substance (5) from a nozzle (4), (9) is composed of a crucible (3), a heating filament (6), and a heat shield plate (7). It is a source of steam generation.

(10) is an electron beam emitting filament that emits an electron beam, and (11) is this electron beam emitting filament (
10) is an electron beam extraction electrode that extracts and accelerates electrons from the electron beam, (12) is an electron beam emitting filament (10).
(13) is an electron beam emitting filament (1o), an electron beam extraction electrode (11)
and a heat shield plate (12) as an ionization means for the cluster (8). (14) is an ionized cluster ionized by this ionization means (13), (15) is an accelerating electrode that accelerates this ionized cluster (14) with an electric field and imparts kinetic energy;
16) is a substrate on which a thin film is formed.

(17) is the first AC power supply that heats the heating filament (6), (18) is the first DC power supply that positively biases the potential of the crucible (3), and (19) is the first AC power supply that heats the heating filament (6). A second AC power supply for heating, (20) a second DC power supply for biasing the electron beam emitting filament (10) to a negative potential, and (21) a second DC power supply for biasing the electron beam extraction electrode (11) and the crucible (3) to a positive potential. The third DC power supply (22) is the first AC power supply (17), the first DC power supply (18), the second AC power supply (19), and the second DC power supply (22).
2o) and a third DC power supply (21).

The conventional thin film forming apparatus is constructed as described above, and the vacuum chamber (1) is evacuated by the evacuation system (2) until the degree of vacuum reaches approximately IXIO-'mmHg. The electrons emitted from the heating filament (6) are transferred to the first DC power source (1).
8), the accelerated electrons collide with the crucible (3), and are heated to a temperature where the vapor pressure inside the crucible (3) becomes several mmHg. By this heating, the vapor deposition substance (5) in the crucible (3) is evaporated and is injected from the nozzle (4) into the vacuum chamber (1). When the vapor of the vapor deposition substance (5) passes through the nozzle (4), it is acceleratedly cooled by adiabatic expansion and condensed, forming a lumpy atomic group called a cluster (8). This cluster (8
) becomes an ionized cluster (14) by being partially ionized by the electron beam emitted from the electron beam emitting filament (10).The ionized cluster (10) becomes an unionized neutral cluster ( 8) and is accelerated by the electric field formed by the accelerating electrode (15) and collides with the surface of the substrate (16) to form a thin film.

The functions of each DC power supply in the power supply device (22) are as follows. The first DC power supply (18) positively biases the potential of the crucible (3) with respect to the heating filament (6), and causes thermoelectrons emitted from the heating filament (6) to collide with the crucible (3). . A second DC power supply (20) supplies an electron beam emitting filament (1) heated by a second AC power supply (19) to an electron beam extraction voltage $1 (11).
0) to a negative potential and extracts thermoelectrons emitted from the electron beam emitting filament (1o) into the electron beam extracting electrode (11).
The electron beam extraction electrode (11) and the crucible (3) are positively biased with respect to the accelerating electrode (15) at ground potential, and the electric field lens formed between the electron beam extraction electrode (11) and the The acceleration of positively charged ionized clusters (14) is controlled.

[Problem to be solved by the invention 1 In the ICB method using the thin film forming apparatus as described above, the properties of the thin film formed are controlled by intervening ionized clusters (14) and controlling their kinetic energy. Therefore, it is necessary to make the amount of ionized clusters (14) per unit area that impinge on the substrate (16), that is, the ion current density, uniform. However, when this ion current density is measured on the substrate (16), as shown in FIG. There was a problem in that the ionic current density was insufficient to form a homogeneous thin film.

The present invention was made to solve these problems, and an object of the present invention is to provide a thin film forming apparatus that can form a homogeneous thin film over a large area.

[Means for Solving the Problems] The thin film forming apparatus according to the present invention includes a set of electrodes provided between the steam generation source and the ionization means to make the ion current density distribution uniform on the substrate. It is something that

[Function] In this invention, a set of electrodes increases the ionization efficiency at the edge of the substrate and makes the ion current density uniform on the substrate, making it possible to form a homogeneous, high-quality thin film on a large-area substrate. do.

[Example] FIG. 1 is a schematic configuration diagram showing an example of the present invention.
(1) to (22) are exactly the same as those in the conventional thin film forming apparatus described above. (23) is the steam source (9)
The first electrode (24) is one of a set of electrodes provided between the ionizing means (13) and the heat shield plate (7), and has the same potential as the heat shield plate (7). The other electrode is a second electrode having the same potential as the heat shield plate (12).

In the thin film forming apparatus configured as described above, the vapor deposition material (
Cluster (8) of 5) is formed.

Now, considering the case where the first electrode (23) and the second electrode (24) are not present, the existence probability of the formed cluster (8) is calculated in a horizontal section along an arbitrary line A-A' in the ionization means (13). When measured, the results are as shown in FIG. In this figure, the existence probability of cluster (8) is determined by cosnθ distribution with respect to the beam angle, and cluster (8) is confirmed to exist on the substrate (
16) is concentrated in the center. Note that the beam angle θ is determined as shown in FIG.

In addition, the region where the electron beam emitted from the electron beam emitting filament (1o) exists, that is, the cluster (
The cluster ionization region where 8) is ionized is the fourth
It spreads out like the shaded area in the figure.

This figure shows the first DC power supply (18) and the second DC power supply (20).
) and the third DC power supply (21) respectively have IKV and 0.
Ionization means in the case of 4KV and 5KV (13
) shows the potential distribution.

Next, when the first electrode (23) and the second electrode 1 (24) are provided, the ion current drawn by the electric field formed by the accelerating electrode (15) is measured by the substrate (161).
As shown in the figure, the ion current is uniformly distributed in the radial direction of the substrate (16).

Further, the ionization region of the cluster (8) is as shown in FIG. This causes the ionization region of the cluster (8) to be penetrated by the electric field formed by the first electrode (23) and the second electrode (24), and the cluster (8) is concentrated in the central part of the substrate (16). This is because the ionization region is made smaller.

In this way, concentration of the ion current density distribution at the center of the substrate (16) can be eliminated, and a homogeneous thin film can be formed over a large area.

In the above embodiment, the first electrode ff1 (23) and the second electrode (24) are at the same potential as the heat shield plate (7) and the heat shield plate (12), respectively. The second electrode (24) may be biased to a higher potential than the first electrode (23), and the same effect as described above can be achieved.

[Effects of the Invention] As explained above, this invention provides a set of electrodes between the steam generation source and the ionization means to make the ion current density distribution uniform on the substrate. The amount of ions reached per unit area can be made uniform, and a high-quality thin film can be uniformly formed on a large-area substrate.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention, and FIG. 2 is a line section showing the relationship between beam angle and cluster existence probability.
Fig. 3 is a schematic diagram showing the beam angle in Fig. 2, Fig. 4 is a schematic diagram showing the cluster ionization region of the ionization means in the absence of a set of electrodes, and Fig. 5 is a schematic diagram showing the ion current density in the radial direction of the substrate. 6 is a schematic diagram showing the cluster ionization region of the ionization means when a set of electrodes is provided, FIG. 7 is a schematic configuration diagram showing a conventional thin film forming apparatus, and FIG. FIG. 3 is a diagram showing the ion current density in the radial direction of the substrate in the thin film forming apparatus shown in FIG. In the figure, (1) is a vacuum chamber, (3) is a crucible, and (4)
is a nozzle, (5) is a vapor deposition material, (6) is a heating filament, (7) is a heat shield plate, (8) is a cluster, (
9) is a steam generation source, (10) is an electron beam emitting filament, (11) is an electron beam extraction electrode, (12) is a heat shield plate, (13) is an ionization means, (14) is an ionization cluster, (15) is an accelerating electrode, (16) is a substrate, (23) is a first electrode, and (24) is a second electrode. In each figure, the same reference numerals indicate the same or corresponding parts. Fan 1 figure tail 2 figure original 3 figures,! ￥) 4 figures pIO 5 figure board graduation direction (mm) 7 figures fan 8 figures 1 line diameter (mm) Procedural amendment document July 60, 1988

Claims (6)

[Claims] (1) A vacuum chamber maintained at a predetermined degree of vacuum, a substrate placed within this vacuum chamber, and a substrate provided opposite to this substrate,
a steam generation source for ejecting vapor of the deposition material toward the substrate to generate clusters of the deposition material; and a steam generation source disposed between the steam generation source and the substrate to ionize at least a portion of the clusters. ionization means for;
Thin film formation comprising: an accelerating electrode disposed between the ionization means and the substrate, for colliding clusters ionized by the ionization means as well as clusters or vapor of non-ionized vapor deposition material toward the substrate; 1. A thin film forming apparatus, characterized in that a set of electrodes is provided between the vapor generation source and the ionization means to make the ion current density distribution uniform on the substrate. (2) The thin film forming apparatus according to claim 1, wherein among the set of electrodes, the potential of the electrode on the vapor generation source side is lower than the potential of the electrode on the ionization means side. (3) The steam generation source comprises at least a crucible filled with a vapor deposition substance, a heating filament that heats the crucible, and a heat shield plate that blocks the heat of the heating filament. The thin film forming apparatus according to item 1. (4) The ionization means is an electron beam emitting filament;
2. The thin film forming apparatus according to claim 1, further comprising an electron beam extracting electrode that extracts and accelerates electrons from the electron beam emitting filament, and a heat shield plate that blocks heat from the electron beam emitting filament. (5) Thin film formation according to claim 1 or 3, wherein the electrode on the steam generation source side of the set of electrodes has the same potential as the heat shield plate of the steam generation source. Device. (6) The thin film forming apparatus according to claim 1 or 4, wherein the electrode on the ionization means side of the set of electrodes has the same potential as the heat shield plate of the ionization means.