JPH0472060A - Thin-film forming device - Google Patents

Abstract

PURPOSE:To form films without application of heat so that the films can be formed at a low temp. by ionizing evaporated particles by the thermions generated from a filament provided between a grid and an evaporating source thereby increasing the energy thereof. CONSTITUTION:This thin film forming device is formed of a vacuum chamber 1, the evaporating source 13, a counter electrode 10 holding a substrate 18, the grid 11, the filament 12 for generating the thermions, a cylindrical shield 30 enclosing this filament and the above-mentioned evaporating source 13 and means 6, 7, 8, 9 for introducing gases therein. Plural pieces of fine holes are uniformly provided on the wall surface on the evaporating source 13 side of the above-mentioned shield 30 to release the active gas and/or inert gas introduced therein. A power source means 21 is provided and the potential of the magnetic grid 11 is maintained at the positive potential with respect to the potential of the above-mentioned counter electrode 10 and the potential of the filament 12.

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). The present invention relates to a thin film forming apparatus with a novel configuration that can simultaneously realize film formation.

[Conventional technology]

Conventionally, thin film forming apparatuses that use CVD or PVD methods are well known for forming thin films on substrates on which thin films are to be formed.
A device using the PVD method has the advantage of being able to form a dense and strong thin film in a high vacuum.

Various types of thin film forming apparatuses using CVD, PVD, etc. have been proposed in the past, and the methods are extremely diverse. or

There have been problems in that it is difficult to form a thin film on a substrate such as a plastic film that does not have heat resistance, or that the properties of the formed thin film are non-uniform.

Therefore, in order to solve these problems, we developed a thin film forming apparatus that developed the above method by generating a high-frequency electromagnetic field between the evaporation source and the target material 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. Thin film forming apparatuses that utilize a DC ion brating method have been proposed (for example, Japanese Patent Publication No. 52-29971,
(Special 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 apparatus, the evaporated substance evaporated from the evaporation source is first ionized by thermionic electrons from the filament.
This ionized evaporated substance has the characteristic that when it passes through the grid, it is accelerated by the action of the electric field from the grid toward the counter electrode and collides with the substrate on which the thin film is to be formed, forming a thin film with good adhesion. ing.

[Problem to be solved by the invention]

However, in the conventional thin film forming apparatus described above, gas is introduced from one end of the outer wall of the apparatus, and when such a means is used, the distribution of the introduced gas and the discharge within the apparatus are limited by the geometry within the apparatus. Because it is difficult to achieve uniformity due to the geometrical shape, the obtained thin film tends to have non-uniform properties, and if the geometrical shape inside the device changes,
There were drawbacks such as insufficient reproducibility of thin film characteristics and the inability to form an ideal thin film.

In addition, conventional apparatuses have the disadvantage that when an active gas is introduced, the evaporated substances and the target surface are altered, making film formation unstable.

The present invention has been made in view of the above circumstances, and is capable of forming a thin film with extremely strong adhesion to a substrate, allowing the use of non-heat resistant plastic films, etc. as a substrate, and providing a uniform film. It is an object of the present invention to provide a thin film forming apparatus with a novel configuration, which can stably obtain a thin film with characteristics and improve the reproducibility of the thin film characteristics.

[Means to solve the problem]

In order to achieve the above object, the thin film forming apparatus according to claim 1 of the present application includes a vacuum chamber, an evaporation source for evaporating the evaporation substance in the vacuum chamber, and a substrate disposed in the vacuum chamber to evaporate the substrate. a counter electrode held opposite the source;
a grid disposed between the evaporation source and the counter electrode to allow the evaporation substance to pass; a filament for generating thermionic electrons disposed between the grid and the evaporation source; A cylindrical shield having a surrounding hollow wall, and a means for introducing an active gas, an inert gas, or a mixture of both into the inside of the shield wall, and a means for introducing an active gas, an inert gas, or a mixture of both gases into the inside of the shield wall, and a means for introducing an active gas, an inert gas, or a mixture of both gases into the wall surface of the shield on the evaporation source side. A plurality of pores for releasing gas are uniformly provided, and.

The apparatus is characterized in that it includes a power supply means for establishing a predetermined potential relationship such that the potential of the grid is positive with respect to the potential of the counter electrode and the potential of the filament.

A thin film forming apparatus according to a second aspect of the invention is characterized in that, in the thin film forming apparatus according to the first aspect, a plurality of cylindrical meshes are installed inside the hollow cylindrical shield.

The thin film forming apparatus according to claim 3 of the present invention includes a vacuum chamber, an evaporation source for evaporating the evaporation substance in the vacuum chamber, and a substrate disposed in the vacuum chamber so as to face the evaporation source. a counter electrode held between the evaporation source and the counter electrode, a grid disposed between the evaporation source and the counter electrode and capable of passing the evaporated substance, and a filament for generating thermionic electrons disposed between the grid and the evaporation source; a cylindrical shield surrounding the filament and the evaporation source and having a hollow wall divided into two parts, one on the substrate side and the other on the filament and evaporation source side; an exhaust port disposed outside the shield;
Means for introducing an active gas into the hollow part on the substrate side of the wall of the shield, and an inert gas into the hollow part on the filament and evaporation source side so that the amount of inert gas introduced is higher than the amount of active gas introduced. A plurality of pores for releasing the introduced gas are uniformly provided on the inner wall surface of the shield, and the potential of the grid is positive with respect to the potential of the counter electrode and the potential of the filament. The present invention is characterized in that it includes a power supply means for establishing a predetermined potential relationship so that the potentials are the same.

Further, in the thin film forming apparatus according to claim 4, in the thin film forming apparatus according to claim 3, a target is provided in place of the evaporation source, and the potential of the target is set to be a negative potential with respect to the grid, the counter electrode, and the filament. It is characterized by having means.

[For production]

Hereinafter, the structure and operation of the thin film forming apparatus according to the present invention will be explained in more detail.

As described above, the thin film forming apparatus according to claim 1 includes a vacuum chamber, a counter electrode, a grid, a filament for generating thermionic electrons, an evaporation source (single or plural), and the filament and the evaporation source. A cylindrical shield having a surrounding hollow wall, and means for introducing gas into the shield wall, and a wall surface of the shield on the evaporation source side has a plurality of pores for releasing the introduced gas. The electrodes are arranged uniformly and are provided with a power supply means that maintains a predetermined potential relationship between the grid, the counter electrode, and the filament.

Then, an active gas, an inert gas, or a mixture of both is introduced into the shield wall,
The gas is uniformly introduced into the vacuum chamber through the pores provided in the wall on the side of the evaporation source.

The counter electrode is placed in a vacuum chamber and holds the substrate to be deposited facing the evaporation source.

The grid, through which the evaporated substance can pass, is arranged between the evaporation source and the counter electrode and is brought to a positive potential with respect to the potentials of the counter electrode and the filament by means of a power source.

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 portion of the evaporated material from the evaporation source. .

A portion of the evaporated material from the evaporation source is ionized into positive ions by electrons from the filament.

The evaporated substance partially ionized in this way passes through the grid, is further promoted to positive ionization by the ionized gas, and is accelerated toward the substrate by the action of the electric field between the grid and the substrate.

Note that 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, are pulled back by the Coulomb force of the grid, and are further drawn back by the grid. It passes through the grid, 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 by thermionic electrons, so there is no heating due to thermionic electrons, and the temperature of the substrate can be prevented from rising. Any material can also be used as a substrate.

Furthermore, in this thin film forming apparatus, the filament and evaporation source are surrounded by a shield, and uniform gas introduction is possible, so that the influence of the geometrical factors of the apparatus on the ionization is reduced. This makes it possible to stably obtain a thin film with uniform properties and improve the reproducibility of the properties of the thin film.

Next, according to the thin film forming apparatus according to claim 2, in addition to the structure of the thin film forming apparatus according to claim 1, a plurality of meshes are installed inside the shield wall, so that the introduced gas is Diffusion is promoted by colliding with the mesh, and it is possible to efficiently mix many types of gases, and therefore, it is possible to further improve the uniformity of the properties of the thin film.

Next, the thin film forming apparatus according to claim 3 includes a vacuum chamber, a counter electrode, a grid, a filament for generating thermionic electrons, an evaporation source (single or plural), and surrounding the filament and the evaporation source. A cylindrical shield having a hollow wall divided into two parts, one on the substrate side and one on the filament and evaporation source side, and an active gas in the hollow part on the substrate side of the wall of the shield,
A means for introducing an inert gas into the hollow part on the side of the filament and the evaporation source is provided, and a plurality of pores are uniformly provided on the inner wall surface of the shield to quantify the introduced gas, In addition, the structure includes a power supply means for establishing a predetermined potential relationship between the grid, the counter electrode, and the filament.

An active gas is introduced into the hollow part on the substrate side of the wall of the shield, an inert gas is introduced into the hollow part on the filament and evaporation source side, and they are respectively introduced into the vacuum chamber from the pores provided on the inner wall. of gas is uniformly introduced. At this time, since the exhaust port is on the outside of the shield, the gas inside the shield will be exhausted from the opening at the top of the shield.If the amount of inert gas introduced is larger than the amount of active gas introduced, the above filament and the above It is possible to make the concentration of inert gas higher than the concentration of active gas in the vicinity of the evaporation source.

The counter electrode is placed in a vacuum chamber and holds the substrate to be deposited facing the evaporation source.

The grid, through which the evaporated substance passes, is arranged between the evaporation source and the counter electrode and is brought to a positive potential with respect to the potentials of the counter electrode and the filament by power supply means.

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 portion of the evaporated material from the evaporation source. .

A portion of the evaporated material from the evaporation source is ionized into positive ions by electrons from the filament.

The evaporated substance partially ionized in this way passes through the grid, is further promoted to positive ionization by the ionized gas, and is accelerated toward the substrate by the action of the electric field between the grid and the substrate.

Note that 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, are pulled back by the Coulomb force of the grid, and are further drawn back by the grid. It passes through the grid, repeats the vibrating 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 by thermionic electrons, so there is no heating due to thermionic electrons, and the temperature of the substrate can be prevented from rising. Any material can also be used as a substrate.

Furthermore, in this thin film forming apparatus, the filament and evaporation source are surrounded by a shield, and uniform gas introduction is possible, so that the influence of the geometrical factors of the apparatus on the ionization is reduced. This makes it possible to stably obtain a thin film with uniform properties and improve the reproducibility of the properties of the thin film.

In addition, since the concentration of inert gas is higher than the concentration of active gas near the filament and evaporation source, consumption of the filament and alteration of the evaporated material due to active gas are suppressed, making it possible to perform stable film formation. .

Next, the thin film forming apparatus according to claim 4 is the thin film forming apparatus according to claim 3 described above.
A target is provided in place of the evaporation source of the thin film forming apparatus described above, and the apparatus is characterized by having means for setting the potential of the target to a negative potential with respect to the grid, the counter electrode, and the filament, and other configurations. are similar.

In this device, the target is composed of a conductive base material (single substance or compound), and its potential is negative with respect to the grid, counter electrode, and filament, and thermionic electrons flying between the filament and the grid ( Positive) Some of the ionized ions diffuse to the target surface and sputter the target surface at high speed.

A part of the particles constituting the target sputtered by these ions are ionized into positive ions by electrons from the filament. The partially ionized particles from the target pass through the grid, are further promoted to become positively ionized by the ionized gas, and are accelerated toward the substrate by the action of the electric field between the grid and the substrate. .

In addition, in this thin film forming apparatus, the filament and target are surrounded by a shield, and uniform gas introduction is possible, so that the influence of the geometric factors of the apparatus on the ionization can be reduced. This makes it possible to stably obtain thin films with uniform properties.
Moreover, the reproducibility of thin film characteristics can also be improved.

Furthermore, since the concentration of the inert gas is higher than the concentration of the active gas in the vicinity of the filament and the target, consumption of the filament and alteration of the evaporated substance due to the active gas are suppressed, making it possible to perform stable film formation.

〔Example〕

Each of the illustrated embodiments will be described in detail below.

FIG. 1 is a schematic diagram of a thin film forming apparatus showing an embodiment of the invention.

In FIG. 1, a base plate 2 and a Pelger 3 are integrated with a backing 4 interposed therebetween to form a vacuum chamber 1. Here, a hole 2a is formed in the center of the base plate 2, and is connected to a vacuum exhaust system (not shown), and is connected to a vacuum chamber 1.
Maintains airtightness inside. In the vacuum chamber 1, a counter electrode 10, a grid 11, a filament 12, and an evaporation source 13 are provided in order from above to below at appropriate intervals, and each of these members It is held in a horizontal state by electrodes 14, 15, 16, and 17 which also serve as supports. These electrodes 14.15, 16.1
7 are drawn out to the outside of the vacuum chamber 1 through the base plate 2 while maintaining electrical insulation with the base plate 2.

That is, these electrodes 14, 15, 16, 17 are connected to the vacuum chamber 1.
It performs electrical connection and power supply between the inside and outside of the base plate 2, and can serve as a conductive means together with other wiring fittings, and airtightness is ensured at the penetrating portion of the base plate 2.

Here, among the electrodes, the evaporation source 13 supported by a pair of electrodes 17 is for evaporating the evaporation substance, and is a resistance heating type formed by forming a metal such as tungsten or molybdenum into a coil shape. It is configured. However, it may be formed into a boat shape instead of a coil shape. Further, instead of such an evaporation source, an evaporation source used in a conventional vacuum evaporation method, such as an electron beam evaporation source, can be used as appropriate.

On the other hand, a filament 12 made of tungsten or the like for generating thermoelectrons is supported between the pair of electrodes 16 .

The shape of the filament 12 is determined by arranging a plurality of linear filaments in parallel or forming a mesh so as to cover the spread of particles of the evaporated substance evaporated from the evaporation source. There is.

Further, a grid 11 is supported on the support electrode 15, and the grid 11 has a shape that allows the evaporated substance to pass through, and in this example, it has a mesh shape.

Further, a counter electrode 10 is supported on the electrode 14, and a substrate 18 on which a thin film is to be formed is placed on the counter electrode 10 on the side facing the evaporation source 13 (lower side in the figure). It is maintained by an appropriate method. This state is evaporation source 1
When viewed from the side of 3, the counter electrode 10 is placed behind the substrate 18.

Now, the above-mentioned electrodes 14, 15°16.1 which also serve as supports
Reference numeral 7 is a conductor which also serves as an electrode, and the ends thereof protruding outside the vacuum chamber are connected to various power sources as shown.

First, the evaporation source 13 is connected to an evaporation power source 20 via a pair of electrodes 17. Next, a DC power source 21 is provided, and the positive side of this DC power source 21 is connected to the grid 11 via an electrode 15, and the negative side of the DC power source 23 is connected to the counter electrode 10 via an electrode 14.

That is, the potential of the grid 11 is set to be positive with respect to the potential of the counter electrode 10. Thereby, the electric field between the grid 11 and the counter electrode 10 is directed from the grid 11 side to the counter electrode 10 side.

The grid 11 supported by the electrode 15 has a shape that allows the evaporated substance to pass through, for example, a mesh shape.

Furthermore, the filament 12 is connected to both ends of a DC power source 220 via a pair of electrodes 16 . Note that the grounding shown in the figure is not necessarily necessary.

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.

Inside the vacuum chamber 1, there is a cylindrical shield 3o having a hollow wall surrounding the filament 12 and the evaporation source 13.
is installed. Further, the structure is such that an active gas, an inert gas, or a mixed gas of an active gas and an inert gas can be introduced into the wall of the shield 30 by a well-known method.

For example, to the shield 30, a cylinder 6 containing an active gas such as 0□ is connected via a valve 7, and a cylinder 8 containing an inert gas such as Ar is connected via a valve 9. There is. A plurality of pores for releasing the introduced gas are uniformly provided on the wall surface of the shield 3o on the evaporation source side.

Note that FIG. 2 is an embodiment of the invention as claimed in claim 2, and shows an enlarged view of the shield portion. In the configuration of FIG. A cylindrical mesh 33 is installed.

Hereinafter, thin film formation using an example of the apparatus having the configuration shown in FIG. 1 will be described.

First, the Pelger 3 is opened, and as shown in FIG. 1, the substrate 18 on which a thin film is to be formed is held on the counter electrode 10, and an evaporation substance is attached to the evaporation source 13.

The combination of the base material constituting the evaporated substance and the type of introduced gas is of course determined depending on what kind of thin film is to be formed.

For example, A1□0. When forming a thin film, aluminum (A1) can be selected as the evaporator, argon (Ar) can be selected as the inert gas, and oxygen (02) can be selected as the active gas. Also, In2O.

When forming a thin film, indium (
In), oxygen can be selected as the introduced gas.

Now, after installing the substrate and evaporation material, Pelger 3
is closed, and the inside of the vacuum chamber 1 is preliminarily heated to 104 to 10-'Tor.
r, and as required, an active gas, an inert gas, or a mixture thereof is introduced through the pores in the wall of the shield 3o at a pressure of 10-2 to 10-'Torr. . Here, for the sake of concreteness, it is assumed that the introduced gas is an inert gas such as argon.

When the power supply is activated in this atmospheric state, a positive potential is applied to the grid 11 by the DC type [21,
A current is passed through the filament 2 by a power source 22.

The filament 12 is then heated by resistance heating and emits thermoelectrons.

Further, the evaporation source 13 is also heated by the current from the power source 20, and the evaporation substance is evaporated.

The evaporated substance evaporated from the evaporation source 13 spreads out and flies toward the substrate 18, but the outer shell electrons are ejected by the collision with thermionic electrons emitted from the filament 12, and the outer shell electrons are ejected from the - part and the introduced gas. Ionized into ions.

In this way, the partially ionized evaporated material is transferred to grid 1.
1, but at that time, as described above, the ionization rate is further increased due to the collision of the thermionic electrons vibrating up and down in the vicinity of the grid 11 and the ionized introduced gas.

In this way, the evaporated substance ionized into positive ions is accelerated toward the substrate 18 by the action of the electric field directed from the grid 11 toward the counter electrode 10, and collides with the substrate with high energy. This forms a thin film with very good adhesion.

Most of the thermoelectrons emitted from the filament 12 are eventually absorbed by the grid 11, and some of the thermoelectrons pass through the grid 11.
Since it is decelerated by the action of the electric field between the two, even if it reaches the substrate 18, it will not heat the substrate 18.

As described above, in the thin film forming apparatus having the configuration shown in Fig. 1, the ionization rate of the evaporated substance is extremely high, so the active gas is introduced into the vacuum chamber alone or together with an inert gas to form the film. By doing so, when evaporating substances and active gas are combined and a thin compound film is formed by this combination,
A thin film having desired physical properties can be easily obtained.

Note that the thermoelectrons generated by the filament effectively contribute to the ionization of the gas in the vacuum chamber, so it is possible to ionize the evaporated substance even under a high vacuum with a pressure of 10-4 Torr or less. The density of a thin film is usually considered to be smaller than that of a bulk film, but according to the thin film forming apparatus of the present invention, a density extremely close to that of a bulk film can be obtained. This is also one of its major features. Furthermore, by performing film formation under such a high vacuum, the incorporation of gas molecules into the thin film can be extremely reduced, and a highly pure thin film can be obtained.

In addition, the filament and evaporation source are surrounded by a shield, and uniform gas introduction is possible.
It becomes possible to reduce the influence of the geometric factors of the device on the ionization, stably obtain a thin film with uniform properties, and improve the reproducibility of the properties of the thin film.

In addition, the device with the shield structure shown in Figure 2 can mix the gases extremely efficiently when introducing many types of gases, and therefore can improve the characteristics of thin films when performing reactive film formation. It can be made extremely uniform.

As described above, the thin film forming apparatus of the present invention shown in FIGS. It is extremely suitable for the formation of

Next, FIG. 3 is a schematic diagram of a thin film forming apparatus showing an embodiment of the invention according to claim 3.

The only difference between the thin film forming apparatus having the structure shown in FIG. 3 and the thin film forming apparatus having the structure shown in FIG. 1 is the structure of the shield part and the method of introducing active gas and inert gas. Other base plates 2. Pelger 3, backing 4, counter electrode 10, grid 11, filament 12
, evaporation source 13, support electrodes 14, 15, 16, 17
, various power supplies 20, 21, 22, etc., which are denoted by the same reference numerals, are the same, and therefore the description thereof will be omitted.

In the thin film forming apparatus having the configuration shown in FIG. 3, there is a hollow space inside the vacuum chamber 1 divided into two parts, one on the substrate 18 side and the other on the filament 12 and evaporation source 13 side, surrounding the filament 12 and the evaporation source 13. Cylindrical shield 35 with walls of
is installed.

In this case, the exhaust hole 2a is located outside the shield 35. In addition, by a well-known method, an active gas is introduced into the hollow part 35a on the substrate side of the wall of the shield 35, and an inert gas is introduced into the hollow part 35b on the filament and evaporation source side. Introduce it so that it is higher than the amount.

At this time, the concentration of the inert gas is higher than the concentration of the active gas near the filament 12 and the evaporation source 13.

In the example shown in FIG. 3, a cylinder 6 containing active gas such as 02 is connected via a valve 7 to a hollow part 35a of the wall of the shield 35 on the substrate side, and a cylinder 6 containing an active gas such as 02 is connected to the hollow part 35a of the wall of the shield 35 on the substrate side. A cylinder 8 containing an inert gas such as Ar is connected to the hollow portion 35b via a valve 9.

Further, a plurality of pores for releasing the introduced gas are uniformly provided on the inner wall surface of the shield 35.

Next, FIG. 4 is a schematic configuration diagram of a thin film forming apparatus showing an embodiment of the invention as claimed in claim 4. This target 40 is supported by an electrode 41 that also serves as a support, and the electrode 41 that serves as a support is connected to the negative electrode side of the DC power source 23, and the positive electrode side of the DC power source 23 is connected to the support electrode 41. It is connected to the body electrode 14.

It should be noted that other constituent elements with the same reference numerals are the same as those in the apparatus shown in FIG. 3, and therefore their explanations will be omitted.

Thin film formation using the thin film forming apparatus having the configuration shown in FIGS. 3 and 4 will be described below.

First, in the thin film forming apparatus having the configuration shown in FIG.
is held on the counter electrode 10, and an evaporation substance is attached to the evaporation source 13. Of course, the combination of the base material constituting the evaporated substance and the introduced gas species is determined depending on what kind of thin film is to be formed.

For example, when forming an A1□03 thin film, Al can be selected as the evaporation substance, Ar as the inert gas, and 02 as the active gas. Also, In2O.

When forming a thin film, In may be selected as the evaporation substance and O2 may be selected as the introduced gas.

Now, after installing the substrate and evaporation material, Pelger 3
is closed, and the inside of the vacuum chamber 1 is preliminarily set at 10-5 to 10-'To.
The pressure of
It is introduced at a pressure of 0-'Torr. Here, for the sake of concreteness of explanation, the introduced gas is assumed to be 1, for example, oxygen as the active gas and Ar as the inert gas.

When the power supply is activated in this atmospheric state, a positive potential is applied to the grid 11 by the DC power supply 21,
A current is applied to the filament 12 by a power source 22 .

The filament 12 is then heated by resistance heating and emits thermoelectrons.

Further, the evaporation source 13 is also heated by the current from the power source 20, and the evaporation substance is evaporated.

The evaporated substance evaporated from the evaporation source 13 spreads out and flies toward the substrate 18, but the outer shell electrons of the evaporated material and the introduced gas are repelled by collision with thermionic electrons emitted from the filament 12. , is ionized into positive ions.

In this way, the partially ionized evaporated material is transferred to grid 1.
1, but at that time, as mentioned above, the grid 11
The ionization rate is further increased by the collision of the thermoelectrons vibrating up and down near the ionized gas and the ionized introduced gas.

In this way, the evaporated substance ionized into positive ions is accelerated toward the substrate 18 by the action of the electric field directed from the grid 11 toward the counter electrode 1o, and collides with the substrate with high energy. This forms a thin film with very good adhesion.

Most of the thermoelectrons emitted from the filament 12 are eventually absorbed by the grid 11, and some of the thermoelectrons pass through the grid 11.
Since it is decelerated by the action of the electric field between the two, even if it reaches the substrate 18, it will not heat the substrate 18.

As described above, in the thin film forming apparatus having the configuration shown in Fig. 3, the ionization rate of the evaporated substance is extremely high, so by introducing an active gas into the vacuum chamber together with an inert gas and forming a film, the evaporation Even when a substance and an active gas are combined and a compound thin film is formed by this combination, a thin film having desired physical properties can be easily obtained.

Note that the thermoelectrons generated by the filament effectively contribute to the ionization of the gas in the vacuum chamber, so it is possible to ionize the evaporated substance even under a high vacuum with a pressure of 10-4 Torr or less. The density of a thin film is usually considered to be smaller than that of a bulk film, but according to the thin film forming apparatus of the present invention, a density extremely close to that of a bulk film can be obtained. This is also one of its major features. Furthermore, by performing film formation under such a high vacuum, the incorporation of gas molecules into the thin film can be extremely reduced, and a highly pure thin film can be obtained.

In addition, the filament and evaporation source are surrounded by a shield, and uniform gas introduction is possible.
It becomes possible to reduce the influence of the geometric factors of the device on the ionization, stably obtain a thin film with uniform properties, and improve the reproducibility of the properties of the thin film. In addition, in the thin film forming apparatus with the shield structure shown in FIG. 3, the concentration of inert gas is higher than the concentration of active gas near the filament and the evaporation source.
The consumption of the filament and the deterioration of the evaporated substance due to the active gas are suppressed, making it possible to form a stable film.

Next, in the thin film forming apparatus having the configuration shown in FIG. 4, a target 40 is installed in place of the evaporation source 13 of the apparatus shown in FIG. 3, as described above. The combination of the base material constituting this target 40 and the type of introduced gas is of course determined depending on what kind of thin film is to be formed.For example, A1□○,
When forming a thin film, Al can be selected as the target 40, Ar as the inert gas, and 02 as the active gas. In addition, when forming a ZnO thin film, Zn is used as a target and Ar is used as an inert gas.

0□ can be selected as the active gas.

Now, after attaching the substrate and the target, the Pelger 3 is closed and the inside of the vacuum chamber 1 is preliminarily set to 101 to 10-'To.
The pressure of
-'Torr pressure. Here, for the sake of concreteness of explanation, the introduced gas is, for example, oxygen as an active gas,
Ar is used as the inert gas.

When the power supply is activated in this atmospheric state, a positive potential is applied to the grid 11 by the DC power supply 21,
A current is applied to the filament 12 by a power source 22 .

The filament 12 is then heated by resistance heating and emits thermoelectrons.

Ar molecules in the vacuum chamber collide with thermionic electrons emitted from the filament 12, and their outer shell electrons are ejected and ionized into positive ions. These ions reach the surface of the target 40 due to the electric field between the filament and the target. On the other hand, since a negative potential is applied to the target 40, high-speed ions collide with the surface of the target 40, sputtering the base material of the target 40.

The particles thus sputtered and scattered from the target 40 spread out and fly toward the substrate 18, but
A part of the gas and the introduced gas collide with thermionic electrons emitted from the filament 12, causing outer shell electrons to be ejected and ionized into positive ions.

In this way, particles from the partially ionized target pass through the grid 11, as described above.
The ionization rate is further increased by the collision of the thermoelectrons vibrating up and down in the vicinity of the grid 11 and the ionized introduced gas.

In this way, particles from the target that have been ionized into positive ions are accelerated toward the substrate 18 by the action of the electric field from the grid 11 toward the counter electrode 10, and collide and adhere to the substrate with high energy. This forms a thin film with very good adhesion.

Most of the thermoelectrons emitted from the filament 12 are eventually absorbed by the grid 11, and some of the thermoelectrons pass through the grid 11.
8, it is decelerated by the action of the electric field, so
Even if it reaches the substrate 18, it will not heat the substrate 18.

As mentioned above, in the thin film forming apparatus having the configuration shown in Fig. 4, since the ionization rate of particles from the target is extremely high, film formation is performed by introducing an active gas into a vacuum chamber together with an inert gas. Also, when particles from a target and active gas are combined and a compound thin film is formed by this combination, a thin film having desired physical properties can be easily obtained.

Furthermore, since thermionic electrons generated by the filament effectively contribute to the ionization of the gas in the vacuum chamber, it is possible to ionize particles from the target even under a high vacuum with a pressure of 10-4 Torr or less. The structure of the thin film can also be made extremely dense, and although the density of a thin film is usually considered to be smaller than that of the bulk, the thin film forming apparatus of the present invention allows the density of One of the major features is that it can be obtained. Furthermore, by performing film formation under such a high vacuum, the incorporation of gas molecules into the thin film can be extremely reduced, and a highly pure thin film can be obtained.

In addition, since the filament and target are surrounded by a shield and it is possible to introduce gas uniformly, it is possible to reduce the influence of the geometrical factors of the device on the ionization, resulting in uniform characteristics. It is possible to stably obtain a thin film having the following properties, and improve the reproducibility of the properties of the thin film. In addition, in the thin film forming apparatus shown in Fig. 4, the concentration of inert gas is higher than the concentration of active gas near the filament and target, so consumption of the filament and deterioration of the target surface due to active gas are suppressed, resulting in stable production. It becomes possible to form a film.

As described above, the thin film forming apparatus having the configuration shown in FIGS. 3 and 4 can be used to form semiconductor thin films constituting ICs, LSIs, etc., high-purity metal thin films as electrodes thereof, and even optical thin films. extremely suitable for

〔Effect of the invention〕

As explained above, according to the thin film forming apparatus of the present invention as set forth in claims 1, 2, and 3.4, particles from the evaporated substance and the target are ionized and have high electrical energy (electron/ion temperature etc.) Therefore, film formation requiring reactivity and film formation requiring crystallization can be realized without applying thermal energy in the form of temperature (reaction temperature, crystallization temperature), making low-temperature film formation possible. Therefore, even plastic films with no heat resistance can be used as the substrate.

In addition, in the thin film forming apparatus of the present invention, the introduced gas is released uniformly, so a thin film with uniform properties can be stably obtained, and the reaction and ion generation are controlled by the geometry of the apparatus. It becomes possible to reduce the influence of factors, stably obtain a thin film with uniform properties, and improve the reproducibility of the properties of the thin film.

Further, according to the thin film forming apparatus according to the third and fourth aspects, since the concentration of the inert gas is high in the vicinity of the evaporation source and the target, it is possible to suppress deterioration of the evaporated substances and the target surface due to the active gas.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a thin film forming apparatus showing an embodiment of the invention as claimed in claim 1, FIG. 2 is an enlarged view of a shield portion showing an embodiment of the invention as claimed in claim 2, and FIG. FIG. 4 is a schematic diagram of a thin film forming apparatus according to an embodiment of the invention as claimed in claim 3, and FIG. 4 is a schematic diagram of a thin film forming apparatus as an embodiment of the invention as claimed in claim 4. 1... Vacuum chamber, 2... Base plate, 2a.
...Exhaust port, 3...Pelger, 4...Backing. 6...Active gas cylinder, 7,9...Valve,
8... Inert gas cylinder, 10... Counter electrode, -
11... Grid, 12... Filament, 13
...Evaporation source, 14,15,16,17.41...
・Support electrode, 18...Substrate, 20...AC power supply, 21°22.23...DC power supply, 30.3
5...Cylindrical shield, 33...Cylindrical mesh, 35a, 35b...Hollow part, 40...Target. Figure 2 Figure of congee

Claims (4)

[Claims] 1. a vacuum chamber, an evaporation source for evaporating an evaporation substance in the vacuum chamber, a counter electrode disposed in the vacuum chamber and holding a substrate facing the evaporation source, the evaporation source and the counter electrode. a grid disposed between the grid and capable of passing the evaporated substance, a filament for generating thermionic electrons disposed between the grid and the evaporation source, and a cylinder having a hollow wall surrounding the filament and the evaporation source. a shaped shield, and a means for introducing an active gas, an inert gas, or a mixture of both into the inside of the shield wall, and a plurality of means for introducing an active gas, an inert gas, or a mixture of both into the inside of the shield wall, and a plurality of means for releasing the introduced gas on the wall surface on the evaporation source side of the shield. The pores are uniformly arranged. A thin film forming apparatus further comprising a power supply means for establishing a predetermined potential relationship such that the potential of the grid is positive with respect to the potential of the counter electrode and the potential of the filament. 2. 2. The thin film forming apparatus according to claim 1, wherein a plurality of cylindrical meshes are installed inside the hollow cylindrical shield. 3. a vacuum chamber, an evaporation source for evaporating an evaporation substance in the vacuum chamber, a counter electrode disposed in the vacuum chamber and holding a substrate facing the evaporation source, the evaporation source and the counter electrode. a filament for generating thermionic electrons placed between the grid and the evaporation source, and a filament surrounding the filament and the evaporation source and connecting the substrate side to the filament and A cylindrical shield with a hollow wall divided into two parts on the evaporation source side, an exhaust port provided on the outside of the shield, and an active gas, filament and evaporator in the hollow part of the wall of the shield on the substrate side. means for introducing an inert gas into the hollow part on the source side so that the amount of inert gas introduced is higher than the amount of active gas introduced, and the introduced gas is released from the inner wall surface of the shield. A plurality of pores are uniformly provided for the grid, and a power supply means is provided for establishing a predetermined potential relationship such that the potential of the grid is positive with respect to the potential of the counter electrode and the potential of the filament. Characteristic thin film forming equipment. 4. 4. The thin film forming apparatus according to claim 3, further comprising means for providing a target in place of the evaporation source and for setting the potential of the target to a negative potential with respect to the grid, the counter electrode, and the filament.