JPH03267367A - Thin film forming equipment - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application] The present invention relates to a single film forming apparatus, and in particular, it combines strong reactivity, which is an advantage of the CVD method (chemical vapor deposition method), and PVD method (physical vapor deposition method). The present invention relates to a new thin film forming apparatus which can simultaneously realize film formation in a high vacuum, which is an advantage of the above, and which can also easily form multilayer films and mixed films.

[Conventional technology]

Conventionally, as thin film forming apparatuses for forming thin films on thin film forming substrates, those using CVD methods, PVD methods, etc. are well known, and apparatuses using CVD methods are highly reactive.
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 these CVD methods, PVD methods, etc. have been proposed in the past, and the methods thereof are also extremely diverse.

However, with conventional three-film forming equipment, the adhesion between the formed thin film and the substrate on which the thin film is formed (hereinafter referred to as the substrate) is weak, or it is difficult to form a thin film on a substrate that is not heat resistant. And then again.

There was a problem in that it was difficult to obtain good multilayer films and mixed films. In addition, the number of methods that are suitable for mass production has decreased.

Therefore, in order to solve these problems, the present applicant first used a thin film forming apparatus in which a substrate was held on a counter electrode facing an evaporation source, and a grid was placed between the counter electrode and the evaporation source. At the same time, they proposed an apparatus in which a filament for generating thermionic electrons is arranged 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 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 vaporized substance.

By passing 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.

[Problem to be solved by the invention]

By the way, in the conventional thin film forming apparatus described above, it is possible to form a compound thin film of the evaporated substance and the introduced gas, but when forming a multilayer film etc. in a single vacuum chamber, the evaporation Because film formation conditions vary depending on the substance,
There were problems with reactivity, film thickness distribution, etc. when using a device with the same arrangement of evaporation source, filament, grid, counter electrode, etc.

Particularly, in equipment that is often used in mass production and is equipped with a large vacuum chamber with a long distance between the evaporation source and the substrate.

Depending on the gas pressure, the mean free path of the evaporated substance becomes shorter,
As scattering due to collision with gas increases, the ratio of thin film deposition on the substrate to the amount of evaporation becomes extremely small, resulting in the need for a large amount of evaporated material, resulting in high costs. Conventionally, when forming a mixed film, methods such as evaporation using a mixed substance as an evaporation substance or simultaneous evaporation using multiple evaporation sources have been used. It has been difficult to obtain high-quality thin films due to X-effects such as differences in vapor pressure, instability in film-forming rate control, and compositional deviations when using compounds as evaporation sources.

The present invention has been made in view of the above circumstances, and it is possible to form a thin film with extremely strong adhesion to a substrate, and it is also possible to use non-heat resistant plastic or the like as a substrate. The object of the present invention is to provide a new thin film forming apparatus that can form good multilayer films and mixed films, and can also be used for mass production.

[Means to solve the problem]

In order to achieve the above object, the 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 both gases is introduced, and a plurality of evaporation substances installed in the vacuum chamber. an evaporation source for evaporating the evaporation source, a counter electrode arranged to face the evaporation source in the vacuum chamber and holding the thin film forming substrate, and one or more of the plurality of evaporation sources and the counter electrode. a filament for generating thermionic electrons disposed between the filaments and the counter electrode, a vine grid disposed between the filament and the counter electrode to allow W to pass through, and a predetermined electrical state in the vacuum chamber. and a power supply means for electrically connecting the inside of the vacuum chamber and the power supply means.

For the filament, one or more of the plurality of evaporation sources is configured with a jig so that the grid has a positive potential, and the distance relationship between each evaporation source and the counter electrode is different. , and by making it possible to operate multiple evaporation sources, grids, filaments, etc. independently, and performing the film forming operation side by side or simultaneously, it is possible to form multilayer films and mixed films. It is characterized by

Further, in the above thin film forming apparatus, the periphery or part of one or more evaporation sources, filaments, and grids is covered with an adhesion prevention plate.

[For production]

In the thin film forming apparatus of the present invention, the vacuum chamber is configured 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 internal space of the vacuum chamber, and an evaporation source, a counter electrode, The filament and the grid are placed in two parts in the vacuum chamber.

Two or more of the evaporation sources are installed in a vacuum chamber and have a structure in which the evaporation substance is evaporated to the counter electrode side, and the distance relationship with the counter electrode may be the same or different.

The above-mentioned counter electrode is arranged to face the evaporation source, and this counter electrode is designed to hold the substrate on which the thin film is formed on the side facing the evaporation source, and depending on the situation, the substrate position may be adjusted by rotating the substrate, etc. It is possible to move.

The grid allows evaporated substances to pass through,
It is interposed between the evaporation source and the counter electrode, and is brought to a positive potential with respect to the filament by power supply means.

Therefore, when forming a thin film, the generated electric field is directed from the grid toward the filament.

The filament is for thermionic generation and is placed between the evaporation source and the grid.

The power supply means is a means for realizing a predetermined electrical state within the vacuum chamber, and the power supply means and the inside of the vacuum chamber are electrically connected by a conductive means.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

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

In FIG. 1, reference numeral 1 indicates a Pelger, reference numeral 2 indicates a base plate, and reference numeral 3 indicates a backing. The Pelger 1 and the base plate 2 are integrated by a backing 3 to constitute a vacuum chamber, and the internal space of this vacuum chamber is for,
Active gas and/or inert H gas can be introduced by a known appropriate method using an introduction pipe, valve, etc. indicated by reference numeral 4. Further, a hole 2A formed in the center of the base plate 2 is connected to a vacuum system (not shown).

The base plate 2 is provided with electrodes 12, 22, 32, 13, 23, 22, 32, 23, 23, 22, 32, 23, 23, 22, 32, 23, 23, 23, 23, 23, 23, 23, 23, 23, 32, 32, 23, 23, 23, 23, 23, 23, 23, 32, 32, 32, 32, 32, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 32, 32, 2;
3411 are installed. Here and there electrodes 12.2'2
32, 13, 23, and 33 electrically connect the inside and outside of the vacuum chamber, and constitute a conductive means together with other wiring fittings.

Electrode 12122, 3L IL 2'l which also serves as the support
Between the pair of electrodes 12 and 13 of y:3, there is supported a resistive heating type evaporation glO, 11 made of metal such as tungsten, molybdenum, tantalum, etc. in a boat shape.

The shape of the evaporation source may be a coil shape or a crucible shape instead of a boat shape, or an evaporation source used in conventional vacuum evaporation methods such as an electron beam evaporation source instead of such an evaporation source. Any source can be used accordingly. In addition, the distance between the evaporation source 10, 11 and the substrate 100 varies depending on the properties of the evaporated substance, and in some cases, as shown in FIG. , measures are taken to prevent wraparound, or to prevent the adhesion of impurities such as grids, filaments, etc.

A filament made of tungsten or the like for generating thermionic electrons is supported between the pair of electrodes 22 and 23, respectively. The shape of the filaments 20.21 is such that a plurality of filaments 1- are arranged in parallel or in a mesh shape so as to cover the spread of particles of the evaporated substance evaporated from the evaporation source 10.11. It is determined.

A grid 30.31 is supported on each of the electrodes 32.33, and the grid 30.31 is shaped so as to allow the evaporated substance to pass through to the counter electrode 40, in this example. The mesh-like electrode 42 is connected to the counter electrode 40, and the evaporation source 1 of the counter electrode 40 is connected to the counter electrode 40.
A thin film forming substrate 100 is held on the side facing 0.11 by an appropriate method. Further, the counter electrode 40 performs automatic movement by a rotating shaft 41 etc. which also serves as a support, so that the substrate position can be moved within the film forming space. Further, although the electrode 42 is shown as being grounded as it is in the figure, the counter electrode 40 may be biased by turning on the DC power during this time.

The electrode 12.13 supporting the evaporation source 10.11 is connected to an AC power supply So, 51 for heating. Note that this power source may be a DC power source instead of an AC power source, and in the case of a DC power source, the positive and negative directions may be either. It may also be used by switching with a switch or the like.

The electrode 22.23 supporting the filament 20.21 is connected to a power source 60.61, which
Similar to the above power sources 50 and 51, any of AC, DC, and optionally a switching type may be used.

The electrode 32.33 is connected to the positive side of a DC voltage power source 70.71, the negative side of which is connected to the electrode 22.2 in the illustrated example.
It is connected to one side of the third husband. Therefore, Gunodko G.

31 is at a positive potential with respect to filaments 1-20.21, and between grid 30.31 and filament 20.21 the electric field is from grid 30.31 to filament 20.21.
Head to 21. Here, the power supply 70.71 in FIG.
The other half is grounded as it is, but during this time I turned on the DC power and it fired one 210. '', 1, and/or the filament 1-20, 21 may be biased.Also, the power supplies 70, 71 may be switchable like the above-mentioned pond power supplies. Grounding is not necessary.

Now, in the thin film forming apparatus having the configuration shown in FIG. 1, by adjusting the filament heating power source 60.61 and the grid DC power source 70.71, it is possible to create a stable plasma state in the respective film forming spaces. Each of these plasma states can be made into its own state by using an evaporated substance or the like.

Thermionic electrons generated by the filaments 20 and 21 are used to ionize part of the introduced gas and evaporated substances, but
The substrate X is attracted by the electric field from grid 30.31 and is eventually absorbed by grid 30.
oO is not reached, the substrate 100 is not heated by electron impact, and the substrate temperature is prevented from increasing.

Incidentally, in reality, the above-mentioned electrical connection includes switches forming part of the conductive means, and the vapor deposition process is executed by operating these switches, but these switch charts are omitted from illustration. .

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

In FIG. 1, first, the Pel jar 1 is opened, the thin film forming substrate 100 is held on the counter electrode 40 as shown, and the evaporated substance is transferred to the evaporation source 10. Let Ll hold it. This evaporated substance is, of course, determined depending on what kind of thin film is to be formed.

Next, after closing the Pel jar 1 of the vacuum chamber and evacuating the inside of the vacuum chamber to a high vacuum state, 10 to 10 g of active gas, inert gas, or a mixture thereof is added to the vacuum chamber in advance.
Introduce at a pressure of -'Pa. In the present description, it is assumed that the introduced gas is an inert gas such as argon, for example.

In this state, when the apparatus is operated and the evaporation sources 10 and 11 are heated, the evaporated substance is evaporated. The evaporated substance, that is, the particles of the evaporated substance, fly while spreading toward the thin film forming substrate 100, but the negative part and the introduced gas collide with thermionic electrons emitted from the filament 20. Ionized into ions.

In this way, the partially ionized evaporated material is transferred to the grid 3.
0.31, but at this time, the thermoelectrons vibrating up and down in the vicinity of the grid collide with the ionized introduced gas, and are further ionized.

The portion of the evaporated material that has passed through the grids 30 and 31 that has not yet been ionized is further ionized into positive ions by collision with the ionized introduced gas, increasing the ionization rate. At this time, in the case of vacuum evaporation, trace gas introduction vacuum evaporation, and trace gas introduction plasma deposition, the mean free path is long and scattering of evaporated substances due to collisions with gas molecules, ions, etc. is small, so the distance between the evaporation source and the substrate is reduced. Even if the distance is long, there is a high probability that the evaporated substance will reach the substrate. However, when the gas pressure is high, the probability that the evaporated material reaches the substrate is low, and a large amount of evaporated material is required, resulting in high costs. Also, when considering the film thickness distribution, when the gas pressure is high, even if the distance between the evaporation source and the substrate is short, the range of the evaporated material expands due to scattering by gas molecules, ions, etc., so it becomes uniform. It's easy, so there's no need to make it long. Therefore,
It is better to change the distance between the four evaporation source plates depending on the purpose.

Now, the evaporated substance that has been ionized into positive ions is
Due to the action of the electric field directed from the grids 30, 31 toward the counter electrode 40, it is accelerated toward the deposition target substrate 100, and collides with and adheres to the deposition target substrate 100 at high speed.

Since the thin film thus formed is formed by the collision of ion particles with the substrate, it has excellent adhesion to the substrate 100 and good crystallinity.

Furthermore, when film formation is performed by introducing an active gas alone or together with an inert gas as the introduced gas, the evaporated substance can be combined with the active gas to form a compound thin film.

In the thin film forming apparatus of the present invention, since the ionization rate of the evaporated substance is extremely high and stable, a compound thin film having desired physical properties can be easily and reliably obtained.

Here, two cases of forming a multi-N film will be described.

First, an evaporation material is selected depending on the thin film to be obtained, and the evaporation material is placed on each evaporation source. Then, the first layer is formed by the method described above. At this time, the substrate 100 is rotated (for a few seconds) to ensure that there is no unevenness in the film thickness. next,
For the second and subsequent layers, the substrate is rotated in the same manner as the first and g-th layers, and a film is formed on top of the first layer to form a multilayer film.

As described above, in the thin film forming apparatus of the present invention, the distance between the evaporation source and the substrate can be changed depending on the thin film to be manufactured, and the thin film can be formed under film forming conditions suitable for the thin film to be manufactured. In addition, insulator film,
Even in the case of a multilayer film in combination with a conductor film, stability can be achieved by covering the grid and filament periphery with an anti-adhesion plate 5, etc., as shown in Figure 2, to prevent insulators etc. from directly adhering to these. Film formation can be performed under the following film formation conditions. In addition, in combination with normal vacuum evaporation, it is also possible to form a multilayer film by using the one with a better distance between the evaporation source and the substrate as the evaporation source for vacuum evaporation, and the shorter one as the evaporation source for the above method in which gas is introduced. be.

For example, argon is used as an inert gas, and argon is used as an active gas.
Introducing the element, adjusting the pressure to 10 to 1 O-2 Pa, selecting indium, tin, etc. as the upper evaporation source, and using Si, SiO, etc. as the lower evaporation source, S iOz / I n 20. /SLO three-layer reflective antistatic coating etc. can be formed.

In addition, in the case of forming a self-contained film, a plurality of layers are simultaneously deposited and mixed on the substrate by rotating the substrate to form a film. With water deposition equipment, it is possible to deposit films using different methods using separate evaporation sources. By changing the moving speed, etc., a mixed film with a good mixing ratio and reproducibility can be obtained.

For example, argon is introduced as an inert gas, oxygen is introduced as an active gas, the pressure is adjusted to 10 to 1 O-2 Pa, and the evaporation substances are Ce in the film formation space A and Si in the film formation space B.
Using O, Ce2O, (refraction: $D=1.95) and 810. (n=1.47), Ti and Zr, Ti02 (n=2.4), ZrO2 (n=2.
A mixed film of 1) is formed, and the refractive index can be changed by changing the mixing ratio.

In the thin film forming apparatus described above, if the above film forming direction is used for more than one evaporation source, the other evaporation sources may perform normal vacuum evaporation. FIG. 3 shows an embodiment of the λ film forming apparatus in that case, and the same reference numerals as in FIG. 1 are constituent members that have the same functions and effects. Moreover, FIG. 4 is a diagram showing an example in which an adhesion prevention plate 5 is installed in the thin film forming apparatus shown in FIG. 3.

By the way, in the thin film forming apparatus shown in FIGS. 1 to 4, thermionic electrons generated by the filament effectively contribute to the ionization of the evaporated substance and the introduced gas.
It is possible to ionize the evaporated substance even under a high vacuum with a pressure below, and therefore the incorporation of gas molecules into the thin film can be extremely reduced, making it possible to obtain a highly pure thin film. In addition, it is possible to make the thin film structure extremely dense, and in addition, it is possible to form three films with good reliability at a low substrate temperature, making it suitable for optical applications not only on glass but also on plastic. This device is extremely suitable for forming thin films.

〔Effect of the invention〕

As explained above, according to the thin film forming apparatus of the present invention,
Since the film is formed using a method that increases the ion C level even at low gas pressure, even multi-N films such as Compound A film can be formed densely with good adhesion, and the applicable gas pressure range is wide, making it suitable for mass production. It is also easy to obtain a uniform film thickness distribution.

In addition, the evaporated substances are ionized and have high energy (electrons and
Optical thin film It becomes possible to form multilayer films and mixed films at low temperatures, which are often used in applications such as the following.

Therefore, according to the present invention, multiple films, mixed films, etc. can be produced on a substrate with good quality and precision at low temperatures, so that the range of application to plastic optical parts and the like can be expanded. Further, the thin film forming apparatus according to the present invention has excellent mass productivity and is a practical apparatus.

[Brief explanation of drawings]

Country 1 is a schematic configuration diagram of a thin film forming apparatus showing an embodiment of the present invention, and FIG. 2 is a schematic diagram of a thin film forming apparatus showing an embodiment in which an adhesion prevention plate is installed in the thin film forming apparatus shown in 1Z. Fig. 3 is a schematic block diagram of a thin film forming apparatus showing another embodiment of the present invention, and Fig. 4 shows an example in which an adhesion prevention plate is installed in a thin film forming apparatus shown in a third country. 1 is a schematic configuration diagram of a thin film forming apparatus shown in FIG. 1...Pelger, 2...Base plate, 3
... Backing, 4... Gas introduction pipe and valve, 5... Anti-adhesion plate, 10.11... Evaporation source, 22, 23.32.33... Support body Dual-purpose electrode...filament, 30.31...grid, electrode, 41...rotating cloth 542...electrode, 50°6
1...2 current power supply, 70.71...DC power supply, thin film forming substrate. 12, 13゜20, 21... 40... vs. Sl, 60゜100... η

Claims (2)

[Claims] 1. a vacuum chamber into which an active gas, an inert gas, or a mixture of both gases is introduced; a plurality of evaporation sources installed in the vacuum chamber for evaporating evaporation substances; a counter electrode arranged to face the substrate and holding the thin film forming substrate; a filament for generating thermionic electrons disposed between one or more of the plurality of evaporation sources and the counter electrode, and the filament and the counter electrode to allow the evaporated substance to pass through; a power supply means for achieving a predetermined electrical state in the vacuum chamber; and a grid for electrically connecting the vacuum chamber and the power supply means. one or more of the plurality of evaporation sources, a jig having a conductive means connected to the filament so that the grid has a positive potential with respect to the filament; Multilayer films and mixed films can be formed by making the distance relationships different for each film, and by making it possible to operate multiple evaporation sources, grids, filaments, etc. independently, and performing film formation operations for each separately or simultaneously. A thin film forming apparatus characterized by being capable of forming a film. 2. 2. The thin film forming apparatus according to claim 1, wherein the periphery or part of one or more evaporation sources, filaments, and grids is covered with an adhesion prevention plate.