JPH0368765A - 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 [Field of Industrial Application] The present invention relates to a thin film forming apparatus. This invention can be used to manufacture plastic lenses and LSIs.

[Conventional technology] Even substrates with low heat resistance such as plastic substrates can be
A thin film forming apparatus for forming a homogeneous thin film with good adhesion has been proposed (Japanese Unexamined Patent Publication No. 89763/1983).

[Problems to be Solved by the Invention] On the other hand, the thin films formed are often required to be multi-component depending on the purpose of use. Combinations of materials are important in such multi-component thin films, but in the conventional device described above, there are limits to the combinations of materials, and it is difficult to adjust the quantitative relationship of the materials to be combined.

The present invention was made in view of the above-mentioned circumstances, and
The aim is to develop a new thin film forming device that can form thin films even on substrates with low heat resistance such as plastics, and that can also combine materials and adjust the quantitative relationship between materials. It's on offer.

[Means to solve the problem] The present invention will be explained below.

The thin film forming apparatus of the present invention includes a vacuum chamber, an evaporation source, a counter electrode, a first . It has a second grid, a filament, a target, and electrical means.

The "vacuum chamber" forms a space for forming a thin film, and an active gas and/or inert gas is introduced into this vacuum chamber as an introduction gas "as needed."

The "evaporation source" is located within the vacuum chamber and evaporates the material. As the evaporation source, various types conventionally known as evaporation sources for vacuum evaporation can be used, such as a resistance heating type used in the embodiments described below, a beam evaporation source, and the like.

The "counter electrode" holds the substrate on which the thin film is to be formed facing the evaporation source in the vacuum chamber.

The "first grid" is formed to allow material particles to pass therethrough and is arranged between the evaporation source and the counter electrode.

The "filament" is for thermionic emission and is placed between the first grid and the evaporation source.

The "second grid" is formed to allow material particles to pass therethrough and is arranged between the evaporation source and the filament.

The "target" is provided closer to the evaporation source than the second grid. The manner in which the target is deployed is determined such that the flight of the evaporated material particles from the evaporation source toward the counter electrode is not obstructed by the target. Targets include materials used as evaporation sources as well as substances that will become thin film materials (conductive base material: single substance or compound)
are used, and one or more can be provided. When providing two or more targets, the base materials may be of the same type or different types.

"The electrical means J is a means for bringing the counter electrode, the first and second grids, the filament, and the target into a desired potential relationship.

That is, the first grid is placed at a positive potential with respect to the counter electrode and the filament.

Further, the target is set at a negative potential with respect to the filament and the first and second grids. The potential of the target is set depending on the amount of base material to be incorporated into the thin film.

The potential of the second grid can be a positive potential, a negative potential, or an O potential with respect to the counter electrode. Therefore, it is possible to arbitrarily set the plasma state in the region between the first grid and the second grid.

Note that "material particles" refer to the introduced gas present in the vacuum chamber,
A general term for atoms, molecules, and ions of material substances and base material substances.

[Function] The active gas, inert gas, or mixed gas introduced into the vacuum chamber is ionized by hot electrons from the filament. Material particles emitted from the evaporation source and base material particles from the target are also ionized by thermionic electrons from the filament.

Since the first grid is at a positive potential with respect to the counter electrode and filament, electric fields are formed in opposite directions from the first grid toward the counter electrode and filament.

The electric field directed from the first grid to the filament acts on the filament as an electric field for extracting thermionic electrons and accelerates thermionic electrons. The electric field from the first grid toward the counter electrode also accelerates the ionized film-forming material toward the substrate.

Thermionic electrons emitted from the filament are attracted to the first grid, move oscillatingly within the electric field around the grid, further promote the ionization of material particles, and gradually reduce their energy, until finally Absorbed into the first grid.

The target is 1st. Since it has a negative potential with respect to the second grid and the filament, it attracts some of the positive polarity ions generated within the vacuum chamber. The attracted ions impact the target, causing material particles in the base material to be ejected. The amount of the base material particles to be ejected can be adjusted by adjusting the magnitude of the voltage applied to the target.

The material particles ejected from the target are also ionized by thermionic electrons and accelerated toward the substrate by the action of the electric field from the first grid toward the counter electrode. The accelerated material particles from the evaporation source and the base material particles from the target collide with the substrate at high speed to form a dense film with good adhesion.

[Examples] Hereinafter, specific examples will be described with reference to the drawings.

In FIG. 1 showing the embodiment, a Pelger 2 is integrated with a base plate 1 via a backing 21 to form a vacuum chamber.

The base plate 1 has an electrode 3°5.7 which also serves as a support.
9, 11, and 14, the penetrating portions of these electrodes are of course airtight, and each of these electrodes and the base plate 1 are electrically insulated. A hole IA bored in the center of the base plate l is connected to a vacuum exhaust system (not shown).

A resistance heating type evaporation source 4 formed of a metal such as tungsten or molybdenum into a coil shape is supported by the pair of electrodes 3 .

A target 6 is supported on the electrode 5 .

The target 6 is supported so as not to impede the flight of material particles flying toward the counter electrode 12 due to evaporation from the evaporation source 4 . FIG. 2 shows the positional relationship between the evaporation source 4 and the target 6 as viewed from the counter electrode 12 side. Note that it is also possible to arrange the target 6 further toward the base plate 1 than the evaporation source 4.

A filament 8 is supported between the pair of electrodes 7. The filament 8 is for thermoelectron emission and is made of a linear filament material such as tungsten. Electrode 7
A power source 19 for heating the filament 8 is connected between them. Although the power source 19 is a DC power source in the embodiment, an AC power source may also be used. Also, as shown in the figure, DC power supply 1
The positive electrode of No. 9 may be grounded, or the negative electrode may be grounded. The filament 8 is formed by arranging a plurality of filament materials in a net shape so that the material particles can pass therethrough, and is arranged so as to cover the spread of the material particles. The filament 8 can also have a shape in which a plurality of filament materials are arranged in parallel.

A first grid 10 is supported on the electrode 9 .

The first grid 10 is also formed to allow material particles to pass through it, and in this example is mesh-like.

A counter electrode 12 is supported at the tip of the electrode 11 .

A substrate 13 on which a thin film is to be formed is supported by this counter electrode 12 in an appropriate manner as shown in the figure.

Further, a second grid 15 is supported on the electrode 14 .

This second grid 15 is also formed to allow material particles to pass therethrough, and in this example has a mesh shape.

The evaporation source 4 is connected to a heating power source 17.

Further, the electrode 9 is connected to the positive terminal of the DC power source 18, and the electrode 11 is connected to the negative terminal. Furthermore, the electrode 5 has a DC power supply 20
The negative electrode of the power source 20 is connected to one end of the filament power source 19, and the positive electrode of the same power source 20 is connected to one end of the filament power source 19.

The positive side of the DC power supply 22 is connected to the electrode 14, and the negative side is connected to the electrode 5. The potential of the target 6 is the same as that of the filament 8, the first . The potential is more negative than that of the second grid 10.15.

The potential of the second grid 15 can be set to positive, negative, or O potential with respect to the counter electrode 12 depending on the combination of the DC power supplies 20 and 22. Note that the grounding shown in FIG. 1 is not necessarily required.

In reality, the connection between each electrode includes various switches, and the thin film forming process is realized by operating these switches, but these switches are omitted from illustration.

Thin film formation using this embodiment apparatus will be described below.

After the substrate 13 is supported by the counter electrode 12 as shown in the figure, the pressure inside the vacuum chamber is reduced to a pressure of 10 -5 to 10 -' Pa using a vacuum exhaust system. Next, as necessary, an inert gas such as argon, an active gas such as oxygen, hydrogen, or nitrogen, or a mixed gas of these active gases and inert gases is introduced as a 10-
A pressure of 2 to 10-'Pa is introduced. This introduction gas is introduced through an introduction pipe (not shown).

The evaporation source 4 holds a material in advance, and the target 6 holds a conductive base material. The evaporated substance, base material, and introduced gas are selected depending on the thin film to be formed.
When forming a thin film of e-Ni alloy magnetic material, Fe or Ni can be selected as the evaporation substance, Ni or Fe can be selected as the base material, and Ar can be selected as the introduced gas. Alternatively, in the case of forming a TO thin film, it is possible to select In as the evaporation substance, Sn as the base material, and 0□ as the introduced gas.

In this state, electrical means is operated to create the above-described desired electrical state within the vacuum chamber.

From the evaporation source 4, the retained material evaporates and spreads in the form of atoms or molecules and flies toward the substrate 12. On the other hand, thermoelectrons are emitted from the filament 8. The thermoelectrons are attracted to the first grid 10 and collide with material particles existing in the vicinity of the first grid to positively ionize these particles. Thus, a plasma state is achieved in the vicinity of the first grid lO.

Some of the ionized material particles are attracted by the negative potential of the target and collide with the target 6, knocking out material particles constituting the base material. Some of the ejected particles are positively ionized by thermionic electrons. At this time, due to the presence of the second grid 15, the influence of the shape, position, and potential of the target 6 on the plasma generated closer to the substrate 13 than the second grid 15 is extremely small.

Therefore, the position and shape of the target 6 and the degree of ion bombardment to the target 6 can be set while keeping the influence on the ionization of the evaporated material extremely small.

Particles of the material due to evaporation and particles from the base material are ionized by thermionic electrons and fly while spreading toward the substrate 12. At this time, the ionization is also promoted by collision with the ionized introduced gas, and further. 1st grid l
When passing through O, ionization is further promoted by the thermoelectrons vibrating in the vicinity of the first grid 10. The thermoelectrons vibrating in the vicinity of the first grid gradually lose energy by ionizing material particles, and are finally absorbed by the first grid 10.

The electric field directed from the first grid 10 toward the counter electrode 12 exerts an accelerating force on the ions of the material particles that have passed through the first grid 10 . As a result, the ions are accelerated toward the substrate 13 and collide with the substrate 13 at high speed to form a dense and homogeneous thin film with excellent adhesion.

[Effects of the Invention] As described above, according to the present invention, a novel thin film forming apparatus can be provided. As mentioned above, this device absorbs thermoelectrons into the grid and does not impact heat the substrate, so it is suitable for forming thin films on heat-resistant substrates such as glass substrates, as well as on non-heat-resistant substrates such as plastic. A thin film can be formed. Furthermore, the material constituting the thin film is accelerated toward the substrate as ions and collides with the substrate with sufficiently high energy, resulting in high adhesion and denseness of the thin film. In addition, since the ionization rate of the material is extremely high, it is easily possible to form a compound thin film by combining the material and the active gas by introducing an active gas alone or together with an inert gas to form a film. .

In addition, since it is easy to control the amount of thin film material taken in from the target, if a doping material is used as the base material of the target, it is possible to easily control the amount of Sn doped when forming an IT○ thin film, etc. Formation of a thin film can be easily achieved.

[Brief explanation of drawings]

FIGS. 1 and 2 are diagrams for explaining one embodiment of the present invention. 103. base plate, 200. Pelger, 400
．． Evaporation source, 600. Target, 809. filament, 10. ,. Nigerid, 15. ,,Second grid, 12,. Telephone v) 4th 7yfDZen “m■W11 3 4 3

Claims (1)

[Claims] A vacuum chamber; an evaporation source for evaporating a material within the vacuum chamber; and a substrate on which a thin film is to be formed is held in the vacuum chamber facing the evaporation source. a first counter electrode disposed between the evaporation source and the counter electrode and capable of passing the material particles;
a grid; a filament for thermionic emission disposed between the first grid and the evaporation source; a second grid disposed between the filament and the evaporation source and capable of passing material particles; A grid 1 disposed closer to the evaporation source than the second grid so as not to impede the flight of material particles evaporated from the evaporation source toward the counter electrode.
The above target, the above counter electrode, first and second grids, a filament,
electrical means for setting the potential relationship of the target to a desired relationship, the first grid being at a positive potential with respect to the counter electrode and the filament, and the target being at a positive potential with respect to the filament and the first and second grids; A thin film forming apparatus characterized in that the potential of the target is negative and the potential of the target can be set according to the amount of particles taken in from the target.