JPH02285070A - Forming device for thin film - Google Patents

Abstract

PURPOSE:To form a thin film excellent in uniformity on a base plate with large adhesive force by utilizing a CVD method and a PVD method in combination and performing film formation in a forming device for the thin film. CONSTITUTION:At the time of forming a thin film of a magnetic material made of e.g. Fe-Ni alloy on the surfaces of a plurality of base plates 13 in a vacuum tank 2, gaseous Ar is introduced into the vacuum tank 2 and Fe 4 of an evaporating source is heated and vaporized by an AC power source 14. Further gaseous Ar is ionized by thermions emitted from a filament 8 and allowed to collide against an Ni target 6 at high velocity to sputter it. Ni particles are accelerated together with the evaporated iron substance by a grid 10 and allowed to collide against the surfaces of a plurality of base plates 13 fitted to a counter electrode 12 as the evaporated iron particles and the sputtered nickel particles having large energy and stuck thereon. The thin films made of magnetic Fe-Ni alloy are formed. In this case, the particles of Fe and Ni are allowed to collide against the counter electrode 12 in the uniform distribution by forming the counter electrode 12, the grid 10 and the target 6 into a concentric spherical shape. The thin films of Fe-Ni alloy having uniform composition and thickness are formed on the surfaces of a plurality of base plates 13 with excellent adhesive force.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is characterized by strong reactivity, which is an advantage of the CVD method (chemical vapor deposition method), and high vacuum deposition, which is an advantage of the PVD method (physical vapor deposition method). At the same time, it is possible to form thin films with excellent uniformity of thin film properties, and it is possible to form extremely uniform multicomponent thin films such as magnetic alloy thin films, oxide superconductor thin films, and semiconductor thin films. The present invention relates to a thin film forming apparatus that can effectively perform the following steps.

[Conventional technology]

Conventionally, thin film forming equipment that uses CVD or PVD methods is well known. CVD equipment is highly reactive, while PVD equipment can form dense and strong thin films in high vacuum. It has the advantage of being able to

Various types of thin film forming apparatuses using CVD, PVD, etc. have been proposed in the past.
In either case, there is a problem in that the adhesion between the formed thin film and the substrate is poor.

Therefore, in order to solve this problem, a thin film forming apparatus developed from the above method generates a high-frequency electromagnetic field between the evaporation source and the object to be evaporated to ionize the material evaporated in active or inert gas. There are thin film forming apparatuses that use the so-called ion blating method, which performs vacuum evaporation and deposits evaporated substances on the object to form a thin film, and also applies a DC voltage between the evaporation source and the object to be evaporated. Thin film forming apparatuses using the DC ion blating method are known (for example, Japanese Patent Publications No. 52-29971 and Japanese Patent Publication No. 52-29091).

Further, as a further developed thin film forming apparatus, the thin film forming substrate is held on a counter electrode facing the evaporation source, and a grid is arranged between the counter electrode and the evaporation source.
An apparatus has been proposed in which a filament for generating thermionic electrons is disposed between the grid and the evaporation source, and the grid is set at a positive potential with respect to the filament to form a thin film (Japanese Patent Application Laid-open No. 89763/1983). . In this thin film forming device,
The evaporated substance evaporated from the evaporation source is first ionized by thermionic electrons from the filament, and as it passes through the grid, the ionized evaporated substance is accelerated by the action of the electric field from the grid toward the counter electrode and forms a thin film. It has the characteristic that it collides with the formation substrate and forms a thin film with good adhesion.

[Problem to be solved by the invention]

By the way, in the above-mentioned conventional thin film forming apparatus.

Although the adhesion of the formed film to the substrate on which the thin film is formed has been improved and is relatively strong, it is still insufficient, and
There were problems such as difficulty in forming a film on a substrate with low heat resistance such as plastic.

In addition, conventional thin film forming equipment is capable of forming various multi-component thin films such as magnetic alloy thin films, ultra-low 4-body oxide thin films, semiconductor thin films, etc., especially ITO films, whose properties change significantly due to doping with trace elements. Unfortunately, when forming a thin film with such properties, it is difficult to effectively incorporate these trace elements into the film, and it is difficult to obtain a thin film with a desired composition ratio.

The present invention has been made in view of the above circumstances, and is capable of forming a thin film having extremely strong adhesion to a substrate on which a thin film is formed and having uniform characteristics.

Even resin substrates with low heat resistance can be used as thin film formation substrates, and it is also possible to form extremely uniform multi-component thin films such as magnetic alloy thin films, oxide superconductor thin films, and semiconductor thin films. It is an object of the present invention to provide a novel thin film forming apparatus that can effectively perform the following steps.

(Means for Solving the Problems) In order to achieve the above object, a thin film forming apparatus according to the present invention includes a vacuum chamber into which an active gas, an inert gas, or a mixture of these gases is introduced, and evaporation in this vacuum chamber. an evaporation source for evaporating a substance; a counter electrode arranged in the vacuum chamber and holding a substrate on which the evaporation substance is deposited so as to face the evaporation source; and between the evaporation source and the counter electrode. a filament arranged between the grid and the evaporation source for ionizing a part of the evaporation substance; the evaporation source has a target disposed therebetween, and means for making the potential of the grid positive with respect to the potential of the filament and the potential of the target negative with respect to the potential of the filament; It can be regarded as a point evaporation source or a micro-planar evaporation source with respect to the substrate placement surface, and a counter electrode.

The grid and target are formed into concentric spherical shapes.

In addition, the substrate arrangement surface is located on the spherical equithickness surface of the point evaporation source or the minute planar evaporation source.

[For production]

In the a′ film forming apparatus according to the present invention, the grid allows the evaporated substance to pass through, is arranged between the evaporation source and the counter electrode, and is placed at a positive potential with respect to the potential of the counter electrode and the filament. In the vacuum chamber, an electric field from the grid toward the substrate and an electric field from the grid toward the evaporation source are formed in opposite directions.

Further, a filament for generating thermionic electrons is arranged between the grid and the evaporation source in the vacuum chamber, and the thermionic electrons generated by the filament are used to ionize a part of the evaporated substance.

Also, part of the evaporated material from the evaporation source is ionized into positive ions by electrons from the filament, and the evaporated material partially ionized in this way.

After passing through the grid, the ionized gas promotes ionization into positive ions, which are accelerated toward the substrate by the action of the electric field.

Here, the electrons from the filament are emitted from the filament with kinetic energy corresponding to the filament temperature, so they are not immediately attracted to the positive potential grid, but pass through it and are pulled back by the Coulomb force caused by the grid. , further passes through the grid, and so on.
It repeats vibrational motion around the grid, and is finally absorbed by the grid. Therefore, the electrons from the filament do not reach the substrate, and the substrate is not subjected to electron bombardment, so that the substrate is not heated and the temperature of the substrate is prevented from rising. Therefore, materials with low heat resistance such as resin can also be used as the substrate material.

The target is composed of a conductive base material (a part of one or more elements or compound elements that make up the thin film), and this target is placed closer to the evaporation source than the filament, and its potential is lower than the filament potential and grid potential. Located at low potential. Therefore, the target potential is at a lower potential than the potential between the grid and the filament. Therefore, ions positively ionized by hot electrons flying between the filament and the grid are diffused to the surface of the target by the electric field between the grid and the filament, collide with the surface of the target at high speed, and sputter the surface of the target. The particles constituting the target sputtered by these ions diffuse into the substrate, reach the thin film to be formed, and become part of the material forming the thin film.

(Example) Hereinafter, the present invention will be explained in detail based on the illustrated example.

FIG. 1 shows a schematic configuration diagram of a thin film forming apparatus showing an embodiment of the present invention. In FIG. 1, a base plate 1
and the Pelger 2 are integrated via a backing 18 to form a vacuum chamber, into which active or inert gas, or a mixture of both gases is introduced.

The base plate 1 has an electrode 3°5.7 which also serves as a support.
, 9.11, but the penetration parts of these support electrodes 3, 5, 7, 9.11 are naturally airtight, and furthermore, these support electrodes 3, 5, 7, 9
, 11 and the base plate 1 are electrically insulated. In addition, a hole IA drilled in the center of the base plate 1
is connected to a vacuum exhaust system (not shown).

A pair of support electrodes 3 located at the center of the base plate 1 support a resistance heating type evaporation source 4 made of metal such as tungsten or molybdenum between the electrodes. In addition, if it can be considered as a point-like or minute planar evaporation source with respect to the substrate surface, a beam-type evaporation source can be used instead of such a resistance heating type evaporation source, which is used in the conventional vacuum evaporation method. Any evaporation source can be used as appropriate.

Now, a target 6 is supported on the support electrode 5. This target 6 is provided with an opening so that the evaporated particles from the evaporation source 4 can reach the substrate while maintaining its distribution, and in this example, it has a mesh shape. In addition to this, a target having an opening as shown in FIGS. 2(a) and 2(b) may be used and the target or substrate may be rotated.

A filament 8 made of tungsten or the like for generating thermionic electrons is supported between the pair of electrodes 7 that also serve as supports. It is determined to cover the spread of the substance evaporated from the evaporation source 4 by, for example, Note that the target 6 is disposed between the evaporation source 4 and the filament 8.

A grid 10 is supported on the support electrode 9, and the grid 10 has a shape that allows the evaporated substance to pass through, and in this example, it has a mesh shape.

A counter electrode 12 is supported on the support electrode 11,
Below that, that is, on the side facing the evaporation source 4, there is an evaporation source 4.
A substrate 13 on which the evaporated material is deposited is held in an appropriate manner. Note that when this state is viewed from the side of the evaporation source 4, the counter electrode 12 is placed behind the substrate 13.

Note that the target 6, grid 10. The counter electrode 12 is formed into a concentric spherical shape, and the counter electrode 12 is arranged so that the substrate surface is located on the equal thickness plane from the evaporation g4.

Now, each of the support electrodes 3, 5, 7, 9゜11 is formed of a conductor and also serves as an electrode, and the vacuum chamber of these support electrodes 3, 5, 7゜9.11 Between the outwardly projecting ends are various power supplies 14. as shown.
15.16.17 are connected.

First, a pair of support electrodes 3 for the evaporation source 4 are connected to an evaporation power source 14, and furthermore, in the illustrated example, a support electrode 9 that supports the grid 10 is connected to a DC voltage power source 15. A counter electrode 12 and a support electrode 11 that supports the substrate 13 are connected to the negative terminal of a DC voltage power source 15, respectively. Further, a DC power source 16 is connected to the south end of the pair of support electrodes 7 that support the filament 8 . In the illustrated example, the positive pole of the DC power supply 16 is grounded, but the negative pole of the DC power supply 16 may be grounded, or an AC power supply may be used instead of the DC power supply 16. The negative electrode of a DC power source 17 is connected to the support electrode 5 that supports the grid-shaped target 6, and the positive electrode of this DC power source 17 is connected to the filament DC power source 16.
connected to one end of the

Note that the grounding shown in the figure is not necessarily required. Also.

In reality, these electrical connections include various switches, and the film forming process is realized by operating these switches, but these switches are not shown in the figure. Omitted.

One configuration of the thin film forming apparatus according to the present invention has been described above based on FIG. 1, but instead of the configuration shown in FIG. 1, the thin film forming apparatus may be configured as in the embodiment shown in FIG. 3.

Here, the configuration shown in FIG. 3 is an example in which a minute planar evaporation source is used instead of the point evaporation source of the thin film forming apparatus shown in FIG. 1, and the other configurations are shown in FIG. It is exactly the same as the device.

Now, an example of the schematic configuration of the thin film forming apparatus according to the present invention has been shown above with reference to FIGS. 1 and 3, and the following details.

Thin film formation using these devices will be explained.

Note that the only difference between the device shown in FIG. 1 and the device shown in FIG. 3 is the shape of the evaporation source, so here we will explain the device using the point evaporation source shown in FIG. 1 as an example. do.

In FIG. 1, after the substrate 13 is set on the counter electrode 12 as shown, the evaporated substance is held at evaporation@4.

Here, the combination of the evaporated substance, the base material constituting the target 6, and the gas species introduced into the vacuum chamber is determined depending on what kind of thin film is to be formed.
When forming a Ni alloy magnetic material, F is used as an evaporated substance.
e, Ni can be selected as the base material of the target 6, and Ar can be selected as the introduced gas. Of course, Fe may be selected as the base material of the target 6 and Ni may be selected as the evaporation substance.

In addition, when forming a Y-Ba-Cu-○ oxide superconducting thin film, Ba is used as the evaporator, Y and Cu are used as the base material of the target 6, and oxygen or a mixture of oxygen and an inert gas is used as the introduced gas. Gas can be selected.

In addition, when forming an indium oxide-based ITO thin film, In is used as the evaporator, and S is used as the base material of the target 6.
n. Oxygen can be selected as the introduced gas.

Now, the inside of the vacuum chamber is set to a pressure of 101 to 10'' torr in advance, and if necessary, an active gas, an inert gas, or a mixed gas thereof is added to a pressure of 10 to 1 torr.
It is introduced at a pressure of 0-'torr. Here, for the sake of concreteness of explanation, it is assumed that the introduced gas is an inert gas such as argon (Ar).

In this state, when the power source is activated, the evaporation source 4 is heated by the alternating current, a positive potential is applied to the grid 10, and a current is passed through the filament 8. The filament 8 is then heated by resistance heating and emits thermoelectrons.

Argon molecules in the vacuum chamber collide with thermionic electrons emitted from the filament 8, and their outer shell electrons are ejected and ionized into positive ions.

These ions reach the surface of the target 6 due to the electric field between the grid 10 and the filament 8.

On the other hand, since a negative potential is applied to the target 6,
High-speed ions collide with the surface of the target 6, sputtering the base material of the target 6. The particles thus sputtered and emitted fly toward the substrate 13 in the same way as the evaporation material evaporated by the resistance heating of the evaporation source 4.

The evaporated material and sputtered particles, that is, the particles evaporated from the evaporated material by resistance heating of the evaporation source 4 and the particles emitted from the target 6 by sputtering, spread and fly toward the substrate 13, but some of them, The outer shell electrons of the introduced gas are ejected by collision with thermionic electrons emitted from the filament 8, and the introduced gas is ionized into positive ions.

In this way, the partially ionized evaporated material and sputtered particles pass through the grid 10;
Ionization is further promoted by the collision of the thermionic electrons vibrating up and down in the vicinity of 0 and the ionized introduced gas. The unionized portions of the evaporated substances and sputtered particles that have passed through the grid 10 are further ionized into positive ions by collision with the ionized introduced gas between the grid IO and the substrate 13. Ionization rate is increased.

In this way, the evaporated substance and sputtered particles ionized into positive ions are accelerated toward the substrate 13 by the action of the electric field from the grid 10 toward the counter electrode 12, and
It collides with 3 with high energy and sticks to it. As a result, a dense thin film with very good adhesion is formed on the substrate 13.

Further, the film thickness planes of both the evaporated particles and the sputtered particles are on a spherical surface centered on the evaporation source 4.

Since the substrate placement surface is also on the spherical surface, the thickness and composition of the formed thin film can be made uniform, making it possible to create a thin film with extremely uniform properties. Furthermore, even if the evaporation source 4 is a micro-planar evaporation source as shown in FIG. It is possible to create thin films with extremely uniform properties.

Incidentally, the majority of the thermoelectrons emitted from the filament 8 are eventually absorbed by the grid 10, and some of the thermoelectrons pass through the grid 10, but the grid 10 and the substrate 13
Since an electric field from the DC power source 15 acts between the grid 10 and the substrate 13, the thermoelectrons passing through the grid 10 are decelerated by the electric field between the grid 10 and the substrate 13, and are pulled back toward the grid 10.

Therefore, even if some of the thermoelectrons reach the substrate 13, the thermoelectrons will not heat the substrate 13 because they are decelerated by the action of the electric field.

Therefore, in the thin film forming apparatus according to the present invention.

A substrate with weak heat resistance can also be used as the substrate 13.

Moreover, in the thin film forming apparatus according to the present invention.

Since the ionization of the evaporated substance is extremely high, by introducing an active gas alone or together with an inert gas into the vacuum chamber to form a film, the evaporated substance and the active gas are combined, and this combination forms a compound thin film. Even when forming a thin film having desired physical properties, it is possible to easily obtain a thin film having desired physical properties.

Furthermore, since thermionic electrons generated by the filament effectively contribute to the ionization of gas in the vacuum chamber, it is possible to ionize the evaporated substance even under high vacuum with a pressure of 10''' Torr or less. The structure can also be made extremely dense, and although the density of a thin film is usually considered to be smaller than that of a bulk, the device of the present invention can achieve a density that is extremely close to that of the bulk. One of its major characteristics is that it can be used.

Furthermore, by forming the film under such a high degree of vacuum, the incorporation of gas molecules into the thin film can be extremely reduced, making it possible to obtain a highly pure thin film. Therefore, the thin film forming apparatus according to the present invention is suitable for forming magnetic alloy thin films and multi-component thin films, and is particularly suitable for forming semiconductor thin films such as ITO whose characteristics change depending on the presence of trace elements.

In the thin film forming apparatus of the present invention shown in FIGS. 1 and 3, for example, if a high-frequency electrode capable of generating a high-frequency electromagnetic field is installed between the grid 10 and the counter electrode 12, the ionization can be effected in this way. Further promoted by high frequency electromagnetic field,
The various effects mentioned above are increased and are more effective.

〔Effect of the invention〕

As described above based on the illustrated embodiment.

According to the present invention, strong reactivity, which is an advantage of the CVD method,
It is possible to provide a thin film forming apparatus that can simultaneously realize film formation in a high vacuum (formation of a dense and strong thin film), which is an advantage of the PVD method.

In addition, in the thin film forming apparatus according to the present invention, since the evaporated substance is ionized and has high electrical energy (electron/ion temperature), film formation that requires reactivity or crystallization is not possible. Since this can be achieved without applying thermal energy such as temperature (reaction temperature, crystallization temperature), it is possible to form a film at low temperatures, and therefore plastics and the like with low heat resistance can be used as substrate materials.

In addition, in the thin film forming apparatus according to the present invention, a target whose base material is a part of the thin film constituent elements is disposed between the evaporation source and the filament. Multi-component thin films such as -Ba-Cu-0 based oxide superconducting thin films can be effectively formed. In particular, it is necessary to effectively dope trace elements into thin films, such as tin doping into indium oxide semiconductor films (ITO) and aluminum doping into zinc oxide films, which greatly affect the properties of thin films. I can do it.

In addition, in the thin film forming apparatus according to the present invention, the film thickness planes of both the evaporated particles and the sputtered particles are on a spherical surface centered on the evaporation source, and the substrate placement surface is also on the spherical surface, so that the film thickness of the evaporated particles and the sputtered particles is The thickness and composition of the thin film can be made uniform, and a thin film with extremely uniform properties can be created.

[Brief explanation of drawings]

Part 1 is a schematic configuration diagram of a thin film forming apparatus showing an embodiment of the present invention, and Fig. 2 is a part showing an example of a target shape. ) is a side view of the target. FIG. 3 is a schematic diagram of a thin film forming apparatus showing another embodiment of the present invention. 1...Base play 1-12...Pelger,
3゜5.7,9,11... Electrode that also serves as support, 4...
... Evaporation source, e----target, 8... Filament, 10... Grid, 12... Counter electrode,
13... Board, 14... AC power supply, 15.16
．． 17...DC power supply, 18...Backing. place? Figures (a) (b)

Claims (1)

[Claims] a vacuum chamber into which an active gas or an inert gas or a mixture of the two is introduced; an evaporation source for evaporating the evaporation substance within the vacuum chamber; and an evaporation source disposed within the vacuum chamber to deposit the evaporation substance. a counter electrode that holds the substrate facing the evaporation source; a grid that is disposed between the evaporation source and the counter electrode and allows the evaporation substance to pass through; and a grid that is disposed between the grid and the evaporation source. a filament for ionizing a portion of the evaporated substance;
a target disposed between the filament and the evaporation source; and means for making the potential of the grid positive with respect to the potential of the filament and the potential of the target negative with respect to the potential of the filament. The evaporation source can be regarded as a point evaporation source or a minute planar evaporation source with respect to the substrate placement surface, and the counter electrode, grid, and target are formed in concentric spherical shapes, and the substrate placement surface is A thin film forming apparatus characterized in that the evaporation source is a point evaporation source or a micro-planar evaporation source on a spherical equi-thickness surface.