JPH05331633A - Vapor deposition device - Google Patents

Abstract

PURPOSE:To prevent the variation in the film forming rate and thin film properties and to facilitate the effective utilization of a vapor deposition raw material and the replenishment of the material. CONSTITUTION:The objective vapor deposition device is a one having a plasma gun 1, a vapor deposition raw material hearth 4 which is the anode of an electron beam and movable in the process of vapor deposition and an auxiliary anode 14 having a potential same as that of the raw material hearth and provided on a position at which heating and evaporating for the vapor deposition raw material 3 by the electron beam are not disturbed and in which the effective anode area viewed from the electron beam and plasma is held to a certain one even when the position of the vapor deposition raw material hearth is changed in the process of vapor deposition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vapor deposition apparatus having an auxiliary anode.

[0002]

2. Description of the Related Art A high current, low voltage plasma gun is 100
A high-current electron beam can be supplied at a voltage as low as V, and the energy of supplied electrons is as low as about 100 eV, so that the reaction gas and the vapor deposition material can be ionized and activated at high density. You can

That is, not only the evaporation source material can be evaporated at a high speed, but also a plasma having a very high reactivity of the evaporation source material can be formed in the evaporation space, so that the evaporation source material can be evaporated on the low temperature substrate at a high speed.
Moreover, it has a feature that a thin film showing excellent performance in various characteristics can be formed at high speed (see Japanese Patent Laid-Open No. 240250/1990).

[0004]

However, when film formation is continued with the raw material hearth fixed, the film formation batches including the film thickness (in this specification, "film formation batch" means the plasma gun power supply). The film characteristics of (1 film forming process from putting in, introducing the substrate to forming a film, and stopping the plasma gun power supply) are stable, but not only the effective use area of the raw material becomes smaller, Cannot easily replenish raw materials. That is, there is a drawback in that the number of continuous film forming batches is limited because it is necessary to stop the film forming to replenish the evaporation material and to open the evaporation space to the atmosphere.

On the other hand, by simply moving the vapor deposition material hearth during vapor deposition, the effective use area of the vapor deposition material is expanded,
Although the supply of raw materials becomes easy and the above-mentioned problems can be solved, there is a drawback that the film forming rate and the thin film characteristics greatly change during film forming or between film forming batches.

That is, since the high current electron beam has a high electron density and the vapor deposition material hearth also functions as an anode for forming a high density plasma,
If this vapor deposition material hearth is moved during vapor deposition, the boundary conditions of the electron beam and plasma will fluctuate significantly, and along with that, the characteristics and spatial distribution of the electron beam and plasma will fluctuate significantly, and the film deposition rate and thin film characteristics will change. It had the drawback of large fluctuations. The object of the present invention is to eliminate the aforementioned drawbacks of the prior art.

[0007]

The present invention has been made to solve the above-mentioned problems, and a plasma gun capable of forming a plasma flow by generating an electron beam,
A vapor deposition raw material hearth that functions as an electron beam anode and is movable during vapor deposition, and an auxiliary anode that has the same potential as the vapor deposition raw material hearth and is provided at a position that does not interfere with heating and vaporization of the vapor deposition raw material by the electron beam, (EN) A vapor deposition apparatus having an auxiliary anode capable of keeping a constant effective anode area as viewed from an electron beam and plasma even when the position of a vapor deposition material hearth is changed during vapor deposition. The vapor deposition apparatus of the present invention has an excellent effect that the vapor deposition raw material can be effectively used and the raw material can be easily replenished without changing the film forming rate and the thin film characteristic.

FIG. 1 (a) is a conceptual cross-sectional view of an example of the vapor deposition apparatus of the present invention, and FIG. 1 (b) is a conceptual plan view of the vapor deposition chamber of the apparatus of FIG. 1 (a). Reference numeral 1 is a plasma gun, 3 is a vapor deposition raw material (hereinafter also simply referred to as raw material), 4 is a vapor deposition raw material hearth (hereinafter, simply referred to as raw material) that holds the vapor deposition raw material 3 and functions as an anode of an electron beam. Reference numeral 6 is a substrate for forming a thin film.

The apparatus of the present invention is an auxiliary anode provided at the same potential as the vapor deposition raw material hearth and at a position that does not hinder the heating and vaporization of the vapor deposition raw material by the electron beam, and changes the position of the vapor deposition raw material hearth during vapor deposition. Even if the auxiliary anode 1 is used, the effective anode area seen from the electron beam and the plasma is kept constant.
It is characterized by having 4. In the apparatus example of FIG. 1, the auxiliary anode 14 is provided between the electron beam and plasma stream 9 and the raw material hearth 4, and has an auxiliary anode opening 15 so as not to prevent heating and evaporation of the raw material 3.

From the viewpoint of the electron beam and the plasma flow 9,
The material hearth portion hidden in the auxiliary anode 14 does not serve as an anode for the electron beam and plasma, and as an effective anode that can be seen from the electron beam and plasma, the fixed auxiliary anode 14 and the auxiliary anode opening are provided. It is limited to only a part of the raw hearth irradiated with the electron beam through the portion 15. Therefore, even if the raw hearth is moved during vapor deposition, the relative position of the effective anode area and the anode is always kept constant as seen from the electron beam and plasma, and the boundary conditions of the electron beam and plasma do not change.

The magnet 5 provided on the back side of the hearth is one of magnetic field forming means for binding the electron beam and forming a magnetic force line for guiding the electron beam onto the vapor deposition material 3, so that the direction of the magnetic force line is vertical. It is arranged and provided at a position where the electron beam can be guided to the electron beam spot 12 on the vapor deposition material 3. A plasma stream 9 is formed along such an electron beam.

The shape of the hearth 4 and the auxiliary anode 14 is not particularly limited, and can be a desired shape such as a quadrangle, a circle or a polygon as shown in FIG. As the method for moving the hearth 4, there are a method of moving the hearth 4 at a constant speed and a moving direction at a constant speed during the film formation, and a method of stopping the hearth during the film formation and moving the hearth an arbitrary distance after the film formation batch is completed. Either method may be selected.

The plasma gun 1 which is a source of the electron beam used in the present invention may be an arc discharge type plasma gun, a hollow cathode type plasma gun or the like as long as it can generate an electron beam. It is preferable to use an arc discharge type plasma gun 1 capable of easily supplying a high-density electron beam, and thereby a high-density plasma. The arc discharge type plasma gun 1 is preferably a composite cathode type plasma generator, a pressure gradient type plasma generator, or a plasma generator in which both are combined. Regarding such a plasma generator, "Vacuum", Vol. 25, No. 10 (1982).
Issued annually).

The composite cathode type plasma generator has an auxiliary cathode having a small heat capacity and a main cathode made of LaB6,
The initial discharge is concentrated on the auxiliary cathode and heated in a short time, and the main cathode LaB6 is heated by using it to heat the main cathode LaB6.
Is a plasma generator that performs arc discharge as the final cathode. For example, a device as shown in FIG.

As the auxiliary cathode 52, a coil made of a refractory metal such as W, Ta or Mo, or a pipe-shaped one can be used. Reference numeral 53 is a disk made of W or the like for protecting the cathode, 54 is a cylinder made of Mo or the like, 55 is a disk-shaped heat shield made of Mo or the like, 56 is cooling water, and 57 is a cathode support base made of stainless steel or the like. , 58 are gas inlets.

In such a composite cathode type plasma generator, the auxiliary cathode 52 having a small heat capacity is intensively heated by the initial discharge to operate as the initial cathode and indirectly La.
This is a method in which the main cathode 51 of B6 is heated, and finally the arc discharge is performed by the main cathode 51 of LaB6. Therefore, before the auxiliary cathode 52 reaches a high temperature of 2500 ° C. or higher and its life is affected, Main cathode 51 is 1500 ℃ ~
It is a great advantage that it is heated to 1800 ° C., a large electron beam can be emitted, and a further temperature rise of the auxiliary cathode 52 can be avoided.

The pressure gradient type plasma generator is
An intermediate electrode is interposed between the cathode and the anode, and the cathode area is several Ts.
The discharge is carried out at about orr and the anode region is maintained at about 10 −3 Torr, and there is no damage to the cathode due to backflow of ions from the anode region, and in comparison with the discharge type without intermediate electrode. The gas efficiency of the carrier gas for producing the discharge electron beam is extremely high, and it has an advantage that a large current discharge is possible.

The composite cathode type plasma generator and the pressure gradient type plasma generator have the above-mentioned advantages, respectively. A plasma generator in which both are combined, that is, a composite cathode is used as a cathode and an intermediate electrode is used. The plasma generator having the above arrangement is also preferable as the arc discharge plasma gun 1 of the present invention because it can obtain the above advantages at the same time.

The structure of the vapor deposition chamber 10 will be described below with reference to FIG. A magnetic field is formed in the axial direction of the plasma gun by the air-core coil 2 which is one of the magnetic field forming means, and the direction of the magnetic field formed at this time is the emission direction of the electron beam from the plasma gun. Further, the vapor deposition material 3 and the vapor deposition hearth 4 are arranged on the side opposite to the substrate 6 with the axis of the plasma gun 1 as the center. A magnet 5 is provided on the back side of the vapor deposition hearth 4 for the purpose of bending the plasma flow containing the electron beam component in the direction of the hearth 4.
Are arranged, and the electron beam is bent along the lines of magnetic force formed by the air-core coil 2 and the magnet 5.

In this case, in order to efficiently focus the magnetic force lines emitted from the plasma gun 1 on the hearth, the magnets 5 are arranged so that the hearth has the S pole and the N pole, and the vaporization hearth is deposited on the plasma gun 1. A voltage from a plasma gun power source 7 is applied so that 4 becomes an anode, and the vapor deposition material 3 is heated and evaporated at an electron beam spot 12 mainly in the plasma stream 9 by an electron beam.

The substrate 6 is arranged so as to face the vapor deposition hearth 4. At this time, the substrate may be heated by the heater 11 or the substrate bias power source 8 may apply a DC or RF substrate bias voltage. When performing the reactive deposition, the reaction gas 13 is introduced.

Further, as shown in FIG. 1, two or more sets of a plasma gun, a vapor deposition material hearth, and an auxiliary anode are arranged side by side in a plane parallel to the substrate so that a thin film can be uniformly formed on a larger substrate. May be.

[0023]

According to the present invention, extremely reactive plasma can be formed in the evaporation space, and a thin film having high speed and excellent characteristics can be easily formed even on a low temperature substrate. In addition to this, there is an effect that the deposition rate and the thin film characteristics do not fluctuate, and the vapor deposition raw material can be effectively used and the raw material can be easily supplied. That is, since the source hearth body can reciprocate around the electron beam spot, the vapor deposition source is consumed over a wide area. Therefore, the effective use area of the raw material becomes large,
Not only the frequency of replenishing the vapor deposition raw material is reduced, but also the raw material can be replenished easily from the portion not irradiated with the electron beam even during film formation.

Further, in the present invention, the raw material hearth portion hidden in the auxiliary anode portion does not serve as an anode for the electron beam and plasma, but is fixed as an effective anode visible from the electron beam and plasma. It is limited to only a part of the raw hearth irradiated with the electron beam through the auxiliary anode part and the hole of the auxiliary anode part.

Therefore, even if the source hearth is moved during vapor deposition, the anode area and relative position are always kept constant in terms of the electron beam and the plasma, and the boundary conditions of the electron beam and the plasma, which are particularly important for large current discharge, are satisfied. This has an excellent effect that fluctuations, that is, fluctuations in the vapor deposition rate and the activity of the vapor deposition material are reduced, and as a result, fluctuations in the film thickness distribution and thin film characteristics are reduced.

[0026]

【Example】

[Embodiment] A pressure gradient type plasma gun as shown in FIG. 2, a raw material hearth capable of translational movement parallel to the traveling direction of a substrate, and an evaporation apparatus of the present invention as shown in FIG. As a vapor deposition material, a sintered body of indium oxide containing 7.5% by weight of tin was crushed and used. As the film formation substrate, non-alkali glass (AN glass manufactured by Asahi Glass) preheated to 200 ° C. was used.

First, the film forming chamber is evacuated to 1 × 10 -5 Torr or less, and then a mixed gas of argon gas and oxygen gas is added.
It was introduced so that the gas pressure was 1 × 10 −3 Torr, the discharge current was fixed at 250 A, and high density plasma was generated. Then, the glass substrate was conveyed at a conveying speed of 45 cm / min to form an ITO film having a film thickness of 2500 Å.

In FIGS. 3 and 4, when the hearth is stopped near the gun for film formation (□), when the hearth is stopped at the center position for film formation (+), the hearth is stopped at a position opposite to the gun. Normalized film thickness distribution and standardized resistivity distribution for each of the cases (◇) (relative values for the film thickness and resistivity when the hearth is close to the gun are standardized and standardized) The change in the specific resistance, which is the same hereinafter), is shown. Each measurement was performed within a range of 60 cm in the width direction perpendicular to the traveling direction of the substrate.

Specific resistance value 190 μΩcm to 150 μΩcm
In addition to obtaining a thin film exhibiting excellent electrical characteristics, as shown in FIGS. 3 and 4, variations in the film thickness distribution and the specific resistance distribution depending on the stop position of the hearth are compared with those of the comparative example shown below. Was less than half. Therefore, it is understood that even when the film is formed while moving the raw hearth by using the auxiliary anode, not only the fluctuations in various characteristics of the thin film in the traveling direction are small, but also the raw material can be easily supplied during the film formation.

[Comparative Example] Using a vapor deposition apparatus as shown in FIG. 1 in which a pressure gradient type plasma gun as shown in FIG. 2 is arranged,
As a vapor deposition material, a sintered body of indium oxide containing 7.5% by weight of tin was crushed and used. However, in this example, the auxiliary heart anode 14 was not used, but the raw material hearth that was capable of translational movement parallel to the traveling direction of the substrate was used. As the film formation substrate, non-alkali glass (AN glass manufactured by Asahi Glass) preheated to 200 ° C. was used.

First, the film forming chamber is evacuated to 1 × 10 -5 Torr or less, and then a mixed gas of argon gas and oxygen gas is added.
It was introduced so that the gas pressure was 1 × 10 −3 Torr, the discharge current was fixed at 250 A, and high density plasma was generated. Then, the glass substrate was conveyed at a conveying speed of 45 cm / min to form an ITO film having a film thickness of 2500 Å. Figure 5,
In Fig. 6, when the hearth is stopped near the gun for film formation (□), when the hearth is stopped at the center position for film formation (+), and when the hearth is stopped at the opposite position for film formation ( The changes in the normalized film thickness distribution and the normalized specific resistance distribution for each of Each measurement was performed within a range of 60 cm in the width direction perpendicular to the traveling direction of the substrate.

Specific resistance value 190 μΩcm to 160 μΩcm
And a thin film showing excellent electric characteristics can be obtained.
As shown in (3), the film thickness distribution and the specific resistance distribution fluctuate greatly depending on the stop position of the hearth. In particular, when a film is formed while the hearth is translated, it is expected that this variation will appear as a large variation in various characteristics in the traveling direction of the substrate.

[0033]

INDUSTRIAL APPLICABILITY The present invention is capable of easily and easily forming a thin film having excellent characteristics even on a low temperature substrate in a vapor deposition apparatus having at least one set of plasma gun, a raw material hearth having a movable mechanism and the auxiliary anode. It has an excellent effect that a film can be formed at a high speed without a change in film speed and thin film characteristics, and that the vapor deposition material can be effectively used and the material can be easily supplied.

Particularly, in the case of an in-line type vapor deposition apparatus in which the vapor deposition container is not opened to the atmosphere between film forming batches, the auxiliary is used from the viewpoint of reducing the frequency of opening to the atmosphere for supplying the vapor deposition material (improving the operating rate of the apparatus). Devices with an anode are highly preferred. That is, if the raw material is replenished from the portion of the raw hearth which is not irradiated with the electron beam, the raw material can be easily supplied even during film formation, and the vapor deposition chamber is separated from the vapor deposition chamber in the translational movement direction of the hearth by the vacuum valve. If a vacuum chamber for filling is provided, the vapor deposition material can be easily supplied without breaking the vacuum state of the vapor deposition chamber after the film formation.

Further, by combining two or more sets of plasma guns and the auxiliary anode, it is possible to form a film in a large area of 1 m × 1 m or more without deteriorating thin film characteristics.

[Brief description of drawings]

1A is a conceptual cross-sectional view of an example of a vapor deposition apparatus of the present invention, and FIG. 1B is a conceptual plan view of a vapor deposition chamber of the apparatus of FIG.

FIG. 2 is a sectional view of an example of an arc discharge type plasma gun used in the present invention.

FIG. 3 is a graph showing the film thickness distribution of the ITO film in the example.

FIG. 4 is a graph showing the resistivity distribution of the ITO film in the example.

FIG. 5 is a graph showing a film thickness distribution of an ITO film in a comparative example.

FIG. 6 is a graph showing a specific resistance distribution of an ITO film in a comparative example.

[Explanation of symbols]

 1: Plasma gun 2: Air core coil 3: Vapor deposition material 4: Vapor deposition material hearth 5: Magnet 6: Vapor deposition substrate 7: Plasma gun power source 8: Substrate bias power source (DC or RF) 9: Plasma flow 10: Vapor deposition chamber 11 : Heater 12: Electron beam spot 13: Reaction gas 14: Auxiliary anode 15: Auxiliary anode opening 51: LaB6 main cathode 52: Ta pipe auxiliary cathode 53: Disk made of W for protecting the cathode 54: Cylinder 55 made of Mo or the like 55: Disc-shaped heat shield made of Mo or the like 56: Cooling water 57: Cathode support pedestal made of stainless steel 58: Gas inlet

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mitsutoshi Murofushi 4-2837 Hachimantai, Yonezawa City, Yamagata Prefecture Asahi Glass Fine Techno Co., Ltd. Company Central Research Institute

Claims (3)

[Claims] 1. A plasma gun capable of forming a plasma flow by generating an electron beam, and a vapor deposition material hearth that functions as an anode of the electron beam and is movable during vapor deposition.
An auxiliary anode that has the same potential as the vapor deposition raw material hearth, is provided at a position that does not prevent heating and evaporation of the vapor deposition raw material by the electron beam, and even if the position of the vapor deposition raw material hearth is changed during vapor deposition,
A vapor deposition apparatus comprising: an auxiliary anode that keeps an effective anode area as seen from an electron beam and plasma constant. 2. A vapor deposition apparatus according to claim 1, wherein a magnetic field forming means for restraining the electron beam and forming magnetic force lines for guiding the electron beam onto the vapor deposition material is provided on the back side of the vapor deposition material hearth. 3. A vapor deposition apparatus comprising two or more combinations of the plasma gun of claim 1, a vapor deposition material hearth, and an auxiliary anode.