JPS63310962A - Thin film forming device - Google Patents

Abstract

PURPOSE:To easily and surely form an excellent thin film at low temp. by deflecting the thermoelectron from an electron gun by a deflecting coil, and introducing the thermoelectron into a space in the vicinity of a grid kept at a positive potential against a substrate holding electrode through a slit. CONSTITUTION:A vaporization source 11 of W, etc., is energized by an electric power source 40 in a vacuum vessel 1, heated, and vaporized. Meanwhile, the thermoelectron generated by the filament 7 of the electron gun 30 is deflected by a couple of deflecting coils 10, and introduced into the space in the vicinity of the grid 6 from the slit SL of a slit member 12. The vaporization substance is ionized by the thermoelectron. The grid 6 is arranged intermediate between the vaporization source 11 and a counter electrode 5 opposed to the source 11 and holding a substrate 100, and kept at a positive potential against the counter electrode 5 by the power source 40. The ion is accelerated by the grid 6, and allowed to collide with the substrate 100 to form the thin film of W or its compd. thereon. The direct hitting of the radiation of the electron gun 30 on the substrate 100 is prevented by the slit member 12.

Description

[Detailed description of the invention] (Technical field) The present invention relates to a thin film forming apparatus.

(Prior Art) Formation methods such as CVD and PvD have been known for forming thin films, and various forming apparatuses using these methods have been proposed.

With the aim of obtaining a thin film that can be formed at low temperatures and has good adhesion, the applicant first installed a thermionic-generating electrode between an evaporation source and a counter electrode that holds a substrate in opposition to the evaporation source. A thin film forming apparatus was proposed in which a filament was disposed and a grid was disposed between the filament and a counter electrode so that the grid had a positive potential with respect to the counter electrode (Japanese Patent Application Laid-open No. 89763/1983).

In this device, the evaporated substance evaporated from the evaporation source is ionized by thermionic electrons from the filament, accelerated by the electric field between the grid and the counter electrode, and applied to the substrate to form a thin film.The potential of the grid relative to the counter electrode is If is too high, ions may be excessively accelerated and may even damage the thin film. Therefore, we want to keep the potential of the grid as low as possible, but if we do this, the hot electrons from the filament will not be strongly accelerated, the density of hot electrons with energy suitable for ionization will decrease, and the ionization rate of the evaporated substance will decrease. Problems may arise in the adhesion and crystallinity of the thin film to the substrate. Therefore, with this device, it is troublesome to adjust the grid voltage in order to form a good thin film.

(Objective) The present invention has been made in view of the above-mentioned circumstances, and its object is to provide a novel thin/film forming apparatus that can easily and reliably form a good thin film at low temperatures. It is provided by.

(composition) Hereinafter, the present invention will be formed.

The thin film forming apparatus of the present invention includes a vacuum chamber, an evaporation source, a counter electrode, a grid, an electron gun, and 5. With power means.

It has a conductive means, a slit member, and an electron guiding means.

An active gas, an inert gas, or a mixture of both gases is introduced into the vacuum chamber. An evaporation source, a counter electrode, a grid, an electron gun, a slit member, and an electron guiding means are arranged in a vacuum chamber.

The evaporation source is a means for evaporating the evaporation substance in a vacuum chamber, and various well-known evaporation sources, such as a coil-shaped one, a boat-shaped one, or an electron beam evaporation source, as described later, can be used. obtain.

The counter electrode holds the substrate, ie, the plate member on which the thin film is to be formed, so as to face the evaporation source.

The grid is disposed between the evaporation source and the counter electrode, and has a shape that allows the evaporation substance to pass through, for example, a mesh shape.

The electron gun is provided to generate electrons for ionizing the vaporized substance, and has a filament for generating thermionic electrons.

The power supply means is means for achieving a predetermined electrical state within the vacuum chamber.

The conductive means is a means for electrically connecting the inside of the vacuum chamber and the electric circuit means.

The slit member has a slit at a position that prevents radiation from the filament from directly hitting the substrate and discharges thermoelectrons into a space near the grid.

The electron guiding means electrically and/or magnetically deflects the trajectory of the thermoelectrons from the filament and guides them into the space near the grid through the slits of the slit member.

During thin film formation, the grid is maintained at a positive potential with respect to the counter electrode by the power supply means.

In the present invention, since the evaporated substance is ionized with electrons from an electron gun, the evaporated substance can be efficiently ionized even if the potential of the grid is lowered.

Further, since the slit member prevents neutral particles, ions, etc. emitted from the filament of the electron gun from directly hitting the substrate, the substrate is not thermally damaged by the radiation.

(Example) Hereinafter, a specific example will be described with reference to the drawings.

In the figure, reference numeral 1 indicates a vacuum chamber. This vacuum chamber is constructed by integrating a Pel jar 3 onto a base plate 2 via a backing 4 to form a sealed space inside. A hole 2a is bored in the base plate 2, and the inside of the vacuum chamber is connected to a vacuum exhaust system (not shown) via the hole 2a, and the airtightness inside the vacuum chamber 1 is maintained while the interior of the vacuum chamber is connected to a vacuum exhaust system (not shown) using a well-known method. It is possible to introduce active gas, inert gas, or a mixture of both.

In the vacuum 1, as shown in the figure, there are an evaporation source 11, a counter electrode 5,
A grid 6, an electron gun 30.1 pair of deflection coils 10, and a slit member 12 are provided.

The electron gun 3o is composed of a filament 7, an auxiliary grid 8, and an anode 9.

Each of these members in the vacuum chamber 1 is a support 13.1.
4, 15, 16, 17, 18.19.

These supports 13 to 19 are all electrically conductive, ensuring insulation from the base plate 2, and
While ensuring airtightness inside the vacuum chamber 1, attach the base plate 2.
It penetrates through and is pulled out of the vacuum chamber. That is, these supports have the function of supporting each member and electrically connecting the members inside the vacuum chamber with the outside of the vacuum chamber,
It constitutes a conductive means together with other wiring fittings.

Note that in the vacuum chamber 1, the counter electrode 5 and the evaporation source 11 are provided in a substantially horizontal state.

The evaporation source 11 is of a resistance heating type formed by forming a coil of metal scraps such as tungsten or molybdenum, for example.
As described above, the evaporation source 11 can be replaced by various evaporation sources conventionally used in vacuum evaporation methods, such as a boat-shaped evaporation source or an electron beam evaporation source.

The power supply means 40 is provided outside the vacuum chamber, and as shown in the figure, an AC power supply 22, a DC power supply 23, 24, 25° 26, . 27
, 28, and also includes various operation switches (not shown).

The above power sources are connected as follows.

First, the AC power source 22 is for heating the evaporation source 11 and is connected to the evaporation source 11 through a pair of supports 15 .

Among the DC power supplies 23, 24, 25, 26, 27, and 28, the power supply 23 has its positive side connected to the grid 6 through the support 14, and its negative side connected to the counter electrode 5 through the support 13. There is. The power source 24 is connected to a pair of supports 19 that support the filament 7 of the electron gun 30, and the positive side of the power source 25 is connected to the negative side of the power source 24.28.
The negative side is connected to the auxiliary grid 8 of the electronic [30] via the support 18. The positive side of the power source 26 is connected to the anode 9 of the electron gun 3o via the support 17, and the negative side is grounded. A power source 27 is connected to a support 16 that supports a pair of deflection coils 10. moreover,
The positive side of the power supply 28 is grounded, and the negative side is connected to the power supply 24.
The grounding shown in the figure is not necessarily necessary.

The grid 6 is configured to have a shape such as a mesh that allows the evaporated substance to pass through, and is set at a positive potential with respect to the counter electrode 5 by the action of the power source 23 . Therefore, an electric field directed from the grid 6 toward the counter electrode 5 is formed between the grid 6 and the counter electrode 5.

The slit member 12 is formed to cover the electron gun 3° and the pair of deflection coils 10 as shown in the figure, and prevents radiation from the filament 7 of the electron gun from directly hitting the substrate held by the counter electrode. It has become.

A pair of deflection coils 10 are electron guiding means and are configured and arranged to generate a deflection magnetic field that penetrates the drawing from the back side to the front side. Electrons emitted from the electron gun 30 enter the magnetic field formed by the deflection coil 10, and their trajectory is deflected by the action of the deflection magnetic field, and the slit member 10
is guided to the slit SL, and exits into the space near the grid 6 through the slit SL.

It should be noted that it is also possible to use additional slits and known electronic lenses in the device shown. Further, the deflection coil 10 and slit member 12 of the electron gun 30.1 may be arranged symmetrically with respect to the horizontal plane including the grid 6 in the figure, and the substrate and the electron gun can be cooled. Of course, it is also possible to provide a pipe or the like for introducing cooling water or the like into the vacuum chamber 1. In addition, the slit member 12
A power supply means or the like may be added to apply a bias voltage to the circuit.

Now, thin film formation using the apparatus of the embodiment will be explained below.

A substrate 100 on which a thin film is to be formed is held by an electrode 5 as shown in the figure, and is opposed to an evaporation source 11 with a grid 6 interposed therebetween. The evaporation source 11 holds an evaporation substance. The evaporation substance used is determined depending on the thin film to be formed, and is, for example, a metal such as aluminum or gold, a metal oxide, fluoride, sulfide, or an alloy.

An active gas, an inert gas, or a mixed gas thereof is introduced into the vacuum chamber 1 at a pressure of 10 to 10-'Pa. Here, for the sake of concreteness of explanation, it is assumed that the introduced gas is an inert gas such as argon.

When the apparatus is operated in this state, the evaporative substance held in the evaporation source 11 evaporates. The evaporated substance, which has been evaporated into fine particles, flies toward the substrate 100 in a spreading manner and passes through the grid 6.

On the other hand, electrons are emitted from the electron gun 30, and these electrons are guided in a counterclockwise trajectory by the deflection magnetic field formed by the pair of deflection coils 10, and are guided through the slit SL of the slit member 12. Pass through and fly towards grid 6. When it hits evaporated matter in flight, it ionizes it.

In this way, a plasma state is realized in the space near the grid. The ionized evaporated substance is accelerated toward the substrate 100 by the action of the electric field from the grid 6 toward the counter electrode 5, and collides with the substrate 100 at high speed.
A desired thin film is formed on 00.

At this time, due to the action of the slit member 12, the substrate 100
is not directly hit by the radiation from the filament 7, and the rise in substrate temperature due to this direct radiation is effectively prevented.
Contamination by radioactive metal ions is also well prevented.

Density and energy of electrons emitted from the electron gun 30,
The spatial distribution can be controlled by the operation of power supply means,
Even when the voltage of the grid 6 is low, the evaporated substance can be effectively ionized.

If a film is formed by introducing an active gas alone or together with an inert gas into the vacuum chamber 1, the evaporated substance can be combined with the active gas, and a thin film of the compound can be obtained.

For example, introduce argon as an inert gas and oxygen as an active gas, adjust the pressure to 10-1 to 1O-2Pa,
If aluminum is chosen as the evaporation material, A
A thin film of 120j can be formed.

Further, in this case, if Si or SiO is selected as the vapor deposition material, a thin film of S x 01 can be obtained.

If In and Zn are selected as evaporative substances, Inzo e
A thin film of ZnO is obtained. Furthermore, if HeS is selected as the gas and Cd is selected as the evaporated substance, a thin film of CdS can be obtained. Furthermore, when ammonia is used together with argon as an active gas and Ti and Ta are used as evaporative substances, TiN, Ta
It is also possible to obtain a thin film of N or the like.

(Effects) As described above, according to the present invention, a novel thin film forming apparatus can be provided.

When forming a thin film using this device, the evaporated substance is ionized and electrically accelerated and has high energy.
There is no need to provide the energy necessary for film formation and crystal packing in the form of heat, and therefore thin films can be formed using a substrate such as plastic, which has poor heat resistance. Furthermore, since sufficient ionization efficiency can be obtained even if the grid voltage is lowered, a high-quality thin film with less damage caused by ion bombardment can be formed. In addition, the effect of the slit member protects the substrate from being directly hit by the radiation from the filament, and the rise in temperature of the substrate due to the direct impact of the radiation as well as the contamination of the thin film by radioactive metal ions are well prevented.

Since the electrons from the electron gun contribute extremely effectively to the ionization of the evaporated substance, it is possible to ionize the evaporated substance even in a high vacuum with a pressure of 10-'Pa or less. The amount of incorporation can be extremely small, making it possible to form a highly pure thin film. Furthermore, the structure of the thin film can be made extremely dense, and although the density of a thin film is normally considered to be smaller than that of the bulk, when it is formed using the apparatus of the present invention, the density of the thin film is approximately the same as that of the bulk. The density is obtained.

The thin film forming apparatus of the present invention is extremely suitable for forming semiconductor thin films constituting LSIs, ICs, etc., and high purity metal thin films used for electrodes.

In the embodiments, magnetic means are used as the electron guiding means, but electric means, such as a capacitor electrode of an appropriate shape, may be used alone or in combination with a magnetic field generating coil.

[Brief explanation of drawings]

The figure shows one embodiment of the invention.

Claims (1)

[Scope of Claims] A vacuum chamber into which an active gas, an inert gas, or a mixture of both gases is introduced; an evaporation source for evaporating an evaporable substance within the vacuum chamber; and an evaporation source disposed within the vacuum chamber. 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 that allows the evaporated substance to pass therethrough; an electron gun having a filament for generating electrons and generating electrons to ionize the evaporated substance during thin film formation; a power supply means for realizing a predetermined electrical state in the vacuum chamber; a slit member having a slit that prevents the board from being directly hit by radiation from the filament and discharges thermoelectrons into a space near the grid; Electron orbits electrically and/or
or a means for magnetically deflecting electrons and guiding them into a space near the grid through the slit, and when forming a thin film, the grid is maintained at a positive potential with respect to the counter electrode by the power supply means. A thin film forming device characterized by sag.