JPH0364456A - Heater with plasma electron beam - Google Patents

Abstract

PURPOSE:To relieve the charge up of a material to be heated and to effectively utilize a plasma electron beam by providing a conductive material having heat resistance in contact with the material to be heated so as to cover the aperture of a hearth and escaping the electrostatic charges of the material to the hearth. CONSTITUTION:The conductive material 16 having the beat resistance is provided in contact with the surface of the material 6 housed in the hearth 5 so as to cover the surface. This conductive material 16 is electrically connected to the hearth 5 or container. The conductive material 16 is so positioned as to receive the irradiation of the plasma electron beam 15a together with the material 6. The electrostatic charges of the material 6 which is dielectrics or insulator escape to the hearth 5 or the container via the conductive material 16 and the charges of the plasma electron beam having the electrostatic charges are decreased. The stable discharge is formed rapidly between a hollow cathode electron gun and the hearth 5 or the container in a short period of time without supplying a large electric power.

Description

DETAILED DESCRIPTION OF THE INVENTION (Prior to Industrial Use) The present invention relates to a plasma electron beam heating apparatus used mainly for heating nonmetals and dielectrics for melting, degassing, evaporation, and the like.

(Prior Art) Conventionally, for example, as an ion blating device, as shown in FIG. 1, a hollow cathode electron gun to which Ar gas is supplied is provided in a vacuum chamber a, and a Ta hollow cathode C is provided.
A water-cooled copper hearth container e containing a conductive material to be heated such as metal d is provided facing the substrate g attached to the substrate holder f, and the electron gun and the container e are connected to a DC electric current r, h and a high frequency generator. It is known that the material d to be heated is melted and evaporated by the heating of the plasma electron beam j from the electron gun, and a thin film of the material d to be heated is formed on the surface of the substrate g. There is.

The hollow cathode electron gun is provided with an auxiliary anode q connected to the positive terminal of the DC power supply 11 via a resistor R and having an opening in the center, and a focusing electromagnetic coil p surrounding the Ta hollow cathode C. It will be done. In Figure 1, L is a vacuum exhaust port, and m is a DC power supply for biasing the plate.

In this device, a DC power source and a high frequency generator (not shown) are connected to a hollow cathode electron gun to generate a discharge, and a plasma electron beam j generated from the opening of the Ta hollow cathode C is used to inject the inside of the container e. The material d is heated and evaporated by irradiating it with the heated monthly charge d. In this case, the auxiliary anode q has the function of extracting a plasma electron beam from the hollow cathode C. To explain this further, at the beginning of the discharge, the discharge occurs between the hollow cathode C and the auxiliary anode q, and the plasma electron beam is drawn out from the hollow cathode C. Although the electron beam is not emitted forward from the hollow cathode C, the auxiliary anode q has a resistor R of, for example, 400Ω.
The electrons flowing through the auxiliary anode circuit connected to the DC power supply have a potential lower than that of the positive electrode of the DC power supply, and the electrons generated by the discharge are accelerated by the low potential of the auxiliary anode q, and the electrons are connected to the hollow cathode. Pull it out in a beam shape from C. The value of resistance R is generally 10Ω to 400Ω, and the auxiliary anode q
is activated only when plasma is generated, and at this time, the current flowing through the auxiliary anode is about IA ~ 15A, which is less than 5% of the electron beam generated from the Ta hollow cathode C, which is within the allowable current value that can be passed through the auxiliary anode at the same time. Almost equal.

The discharge current is maintained by a DC power supply 11.

When attempting to directly heat and evaporate the heated material d, which is a dielectric or an insulator such as an oxide, nitride, fluoride, or sulfide, using the apparatus shown in Figure 1, the material to be heated may be charged up or discharged. Since current cannot be passed through a non-conductive heated material, it is difficult to generate and maintain plasma in a hollow cathode electron gun, or the plasma is unstable, resulting in unstable deposition. Furthermore, when using a hollow cathode electron gun, it is not possible to maintain a sufficient distance from the heated material d, which hinders the evaporation flow from the electron gun container e. However, because the temperature is too high, the material to be heated is locally heated, causing undesirable thermal decomposition.The path of the plasma electron beam is short, so there is less chance of collision between the plasma electron beam and evaporated matter, Ar, etc. The drawback was that the ionization rate of the evaporated matter could not be increased.

In order to eliminate such inconveniences and shortcomings, the inventors of the present invention added W to at least a portion of the auxiliary anode q of the hollow cathode electron gun.
A high melting point conductive material such as % Tas Mo or a heat resistant material such as stainless steel or Ti is used, and the auxiliary anode q is provided to surround the hollow cathode C as shown in the second diagram, and a hollow cathode electron gun is used. He proposed a later method in which a large amount of the plasma electron beam generated by the hollow cathode C is constantly flowed into the auxiliary anode q during operation of the auxiliary anode q to heat the auxiliary anode.

The ion blating apparatus shown in the second figure introduces a gas for generating plasma such as gas or Ar into a hollow cathode electron gun at a flow rate of 200 to 300 SCCM, for example, to a temperature of 1 Torr or less in a vacuum chamber. , when the pressure in the vacuum chamber reaches 0.01 to 0.05 Torr, for example, 80 to
A voltage obtained by fF scanning a high frequency voltage is applied to a DC voltage of 100V. This allows superimposition! °The gas introduced into the hollow cathode electron gun σ) nozzle stimulated by a 5-frequency voltage is ionized and becomes plasma, and by the action of the DC voltage, electrons in the plasma are transferred from the opening at the tip of the hollow cathode to the auxiliary anode and Fly towards the hearth (anode). At the same time, ions fly from the auxiliary anode and hearth toward the hollow cathode. Thus, a discharge is formed between the auxiliary anode and the hearth and the hollow cathode, and the tip of the auxiliary anode is heated by being bombarded by a portion of the electron beam. In this case, the opening of the auxiliary anode is made of +M to avoid direct hit by the electron beam, and a heat-resistant metal such as W, Tas No., or stainless steel is used for the part heated by the electron beam. Therefore, even if a considerable current flows through the auxiliary anode during plasma generation and heating of the material to be heated, its melting is prevented.

This auxiliary anode is heated to 500-2500°C.

In this case, the auxiliary anode works together with the hearth (anode) to extract the electron beam from the hollow cathode, but the heated auxiliary anode works to further heat the hollow cathode, so it prevents the emission of the electron beam from the hollow cathode. This facilitates and stabilizes the generation and maintenance of plasma by the plasma electron beam. Historically, since a large current can be passed through the auxiliary anode, even if the material to be heated inside the water-cooled copper hearth is a dielectric or insulator and a sufficient current cannot be passed from the water-cooled copper hearth, the hollow cathode can be passed through the auxiliary anode. current can flow through.

Usually, the discharge current and discharge voltage are 50 to 500, respectively.
A, 20-907. The material d to be heated is heated by the impact of the plasma electron beam j, and when it reaches the evaporation temperature, the vapor flow n reaches the substrate g, on which a metal film, metal oxide film or nitride film (in the case of reactive vapor deposition) is formed. be done. Due to the ionization effect of the plasma electron beam j, a part of the vapor flow n is ionized and positively charged, and is accelerated toward the substrate g and substrate holder f to which a negative bias voltage is applied by the bias DC power supply m. be done. For the electron gun, A
R gas is supplied, and its flow rate is high at the beginning of discharge, and is reduced after discharge starts. A shutter placed in front of substrate g is opened during deposition.

According to the apparatus shown in the second figure, the distance from the tip of the hollow cathode C of the hollow cathode electron gun to the surface of the heated material d is 2.
Below 00 mm, it is easy and stable to generate plasma, start heating the material to be heated, maintain and control the plasma, and the material to be heated d can be heated without necessarily using an electromagnetic coil. This has the advantage that a beam path can be obtained and the rate of ionization of the evaporated material can be increased.

(Problem to be Solved by the Invention) However, in the device shown in the second figure, the distance from the tip of the hollow cathode C of the hollow cathode electron gun to the surface of the heated material d is 2.
If it exceeds 00 mm, even if you try to irradiate the plasma electron beam to the center of the surface of the material d as shown at j3 in Figure 2 to raise the temperature of the material d, the material d will be insulated. When the plasma electron beam is charged up, a repulsive force is generated between the material to be heated and the plasma electron beam, and the plasma electron beam hits the material to be heated d as shown at j4 in FIG. The hollow cathode electron gun, the material to be heated, the container,
Alternatively, it is difficult to generate a stable discharge between the electrode and the hearth, or it takes a long time or a large amount of power to generate the discharge. However, even if the distance from the tip of the hollow cathode to the surface of the material to be heated exceeds 200 mm, once discharge occurs, the heating of the plasma and the material to be heated will be maintained and controlled stably thereafter. Therefore, it is desirable to easily generate a discharge when the distance is long.

According to the present invention, even if the distance between the hollow cathode and the material to be heated is set relatively long, discharge can be started between the hollow cathode electron gun and the container or hearth on the surface 1, and the discharge can be easily maintained and controlled. Moreover, it is an object of the present invention to provide a plasma electron beam heating device that can uniformly heat the material to be heated without thermally decomposing it, and has a high rate of ionization of evaporated material.

(Means for Solving the Problems) In the present invention, a plasma electron beam from a hollow cathode electron gun connected to a DC power supply is irradiated onto a lotus or a material to be heated housed in a container to heat the material. A conductive phase made of a heat-resistant conductive material is provided in contact with and covers the material to be heated, the conductive material is electrically connected to the hearth or container, and the material is heated by plasma electron beam irradiation. The above object is achieved by dissipating the generated charge on the material to be heated to the hearth or container.

(Function) Evacuate the vacuum chamber to, for example, 10' Torr or less, and
Ar gas is supplied to the hollow cathode electron gun at a rate of 0 to 3009 CCM, and the vacuum chamber is heated to 0.01 to 0.05 Torr.
When the temperature reaches r, a voltage of, for example, 80 to 100 V DC voltage superimposed with a high frequency voltage is applied between the hollow cathode of the electron gun and the hearth and the auxiliary anode to cause a discharge between the hollow cathode electron gun and the hearth. generate.

The hollow cup 15. Hollow shadow plate of rifle and wave force 1+
, the distance from the surface of l#1 material is, for example, 200 to 300 m.
m, and in the case of a heated material, dielectric, or insulator, the plasma electron beam from the hollow cathode electron gun is
Due to the negative charge of the heated material, the heated material deflects upward or to the side, but the heat-resistant conductive material provided in contact with and covering the surface of the heated material prevents the negative charge of the heated material. In order to release part of the charge to the container or hearth, the plasma electron beam is considerably relaxed, and a part of the plasma electron beam impacts the material to be heated and the heat-resistant conductive material above it. Heat these. As the temperature of the heated H material and the conductive material rises, the deviation of the plasma electron beam from the hearth becomes smaller and smaller, and a stable discharge occurs between the hollow cathode electron gun and the hearth in a few minutes to more than ten minutes. . During this time, gradually reduce the amount of Ar gas to the hollow cathode electron gun to keep it below 11005 CC, and also keep the pressure in the vacuum chamber at a low pressure of 0-4 to 10-' Torr. .

After a stable discharge occurs, the plasma electron beam is no longer deviated from the material to be heated. The current from the plasma electron gun to the hearth and auxiliary anode until a stable discharge occurs is up to 20
0~300A, voltage is 30~40V1 power is 5~12K
After stable discharge occurs, both current and power are controlled to lower values than before stable discharge occurs, and the voltage is 35 to 407.
It is easy to control and set.

The heat-resistant conductive material releases the charge caused by the plasma electron beam irradiation of the non-conductor heated material to the hearth or container by secondary electron emission or conductive action, and alleviates the charge caused by the plasma electron beam. The energy of the plasma electron beam is used more effectively to raise the temperature of the material to be heated, and by raising the temperature of the conductive material itself, it helps to raise the temperature of the material to be heated. It is possible to generate an electric discharge between the gun and the hearth.

In addition, even when heating the material to be heated by generating a stable electric discharge and restarting heating after the power is cut off and the material to be heated is completely cooled down, the radiation must be easily generated. I can do it.

(Embodiment) An embodiment of the present invention will be described below with reference to the drawings. FIG. 3 shows a case where it is applied to an ion blating device, and in the drawing, ? :'1 (1) is a vacuum chamber equipped with a true exhaust hole (2), (3) is a substrate holder installed above the vacuum chamber (1), (4) is the bottom surface of the cutting board holder (3) (5) is a water-cooled copper hearth placed in the vacuum chamber (1) downward facing the substrate (4). ,(6)
is the material to be heated housed in the hearth (5).

(8) is a hollow cathode electron gun, (9) is a hollow cathode such as Ta, (IG is a DC power supply installed between the hollow cathode electron gun (8) and the water-cooled copper hearth (5), ('lv is High frequency generator, 1''+2) (IZ indicates a high frequency bypass capacitor.High frequency generator C11) and bypass capacitor aD (I indicates a DC power supply 11)
connected in parallel with a3 is a DC power supply for substrate bias,
0Φ is a shutter, and (1g) is an auxiliary anode.

The above configuration is almost the same as the conventional ion brating apparatus shown in FIG. 1 or 2, and supplies Ar gas to the hollow cathode electron gun (8), When activated, the electron gun (8) starts discharging and a plasma electron beam (15a) is emitted from the opening of the Ta hollow cathode (9), which is the same as in the conventional one.

However, if the material to be heated (6) is a dielectric or an insulator, in the conventional device, the plasma electron beam emitted from the electron gun is subjected to a repulsive force due to the negative charge of the material to be heated, and the plasma electron beam is deflected from the hearth. As a result, the number of plasma electron beams that irradiate the material to be heated decreases, making it impossible to effectively heat the material.
Even if a large amount of electric power is applied to the electron gun, it is difficult to generate a stable discharge between the electron gun and the hearth, or it takes a long time to generate the discharge.However, in the present invention, the heated A heat-resistant conductive material is placed in contact so as to cover the surface of material (6).
'le was provided, the conductive material ae was electrically connected to the hearth (5) or the container, and the conductive material (IG) was irradiated with the plasma electron beam (15a) together with the material to be heated (6). The electrical charge of the dielectric or insulating material to be heated (6) escapes to the hearth (5) or container via the conductive material 00,
;:j)? The plasma electron beam that exceeds li by 11 mm is reduced.

In addition to W, the conductive material (le is Ta5Re, MO
%Nb5Hf and graphite or boron nitride type conductive compound, TaC% Tic S' W2C%
A conductive compound such as ZrC%TaB2 is used, and depending on the type of heating side material, a relatively heat-resistant side material such as Ti or stainless steel may be used.

The heat-resistant conductive material (IO is, as shown in FIGS. 4 to 8, A sheathing part (1f3a) provided in and in contact with the sheathing part (1f3a), and a lead part (I) for electrically connecting this to the hearth (5) or the container.
i), and in the example shown in FIGS. 4(A) and 4(B), one end (IGe) of the lead part (IGJ) is formed of a spring material, and its elasticity allows it to fit with the covering part (1f3a). 5, and the other end (IGf) was electrically connected to the water-cooled copper hearth (5) using screws. In the example shown in FIGS. 5A and 5B, one end (16e) of the lead part (16j) is electrically connected to the covering part (IGa) by welding or simply by contacting it, and the other end ( 16f) placed on the upper edge of the water-cooled copper hearth (5).
), and electrical connection between the covering part (16a) and the water-cooled copper hearth (5) was made through this metal piece (16g). Furthermore, in the example shown in FIGS. 6A and 6B, three lead portions (IOA) are provided so as to span between the covering portion (IGa) and the container (5a) for electrical connection.

The covering portion (16a) made of the heat-resistant conductive material (IO)
In the case shown in Fig. 4, cylinders with uniform wall thickness t1 and height H and different diameters are arranged concentrically with the through holes in the radial direction. In this case, the performance differs depending on the outer diameter C1 height H1 of the hole. Note that the outer diameter C is set smaller than the opening diameter E of the hearth.

The covering portion (IGa) shown in FIGS. 5(A)(B) and 6(A)(B)] 6 is in the shape of a disc-shaped plate sieve with an outer diameter C1 and a plate thickness H. Through-hole portion L represented by the diameter of the hole, center distance MS of the round hole
It is preferable that the outer diameter C is set smaller than the opening diameter of the container (5a).

Furthermore, the covering portion (IGa) shown in FIG. 7 has an outer diameter C1 and a wire diameter H.
It has the shape of a disc-shaped mesh sieve, and its performance is
, varies depending on the diameter H of the wire. This outer diameter C is the container (5a
) is smaller than the opening diameter.

Further, the covering part (IGa) shown in FIG. 8 is configured in a disk shape with an outer diameter C1 and a height H by combining a plate material having a thickness t and a width H, and a plate plate having a thickness u1 and a width H in a lattice shape. Its performance varies depending on the plate thickness t and u of the through-hole portion L1.

The variously shaped covering parts (16a) are either provided at the opening of the water-cooled copper hearth (5) as shown in the fourth figure, or are heat-resistant and fitted into the water-cooled copper hearth (5) as shown in the fifth figure. It is optional whether it is provided at the opening of the container (5a) or at the opening of the heat-resistant conductive container (5a) placed on the water-cooled copper block (7) as shown in the sixth figure. In either case, a part of the covering part (16a) is heated material (6
), and may be partially buried as shown in FIGS. 4 and 8.

In addition, the conductive material ('IO lead part (IGj) is composed of a Ta plate material with a thickness of 1 mm, a width of 10 mm, a length of 60 mm, and a Ta burning wire with an outer diameter of 2 mm in the example shown in Figure 4.
In addition, in the example shown in Figure 5, the lead part (16f is 1 mm thick)
5 width 10mm.

It is made of Ta plate material with a length of 50+n+n, and in the example shown in FIGS. 6 to 8, the lead part (IOA) is made of a 1 m thick
It was constructed from a W-shaped L-shaped plate with a width of 10 mm and a length of 25 mm.

The water-cooled copper hearth (5) shown in FIG. 5 has an outer diameter of 75 m+n.

It has a cylindrical shape with a height of 63 mm, an inner diameter of the top opening of 10 mm, a depth of 28 mm, and an internal volume of 62 cc.The container (5a) of the embodiment shown in Fig. 6 is made of Mo, has a wall thickness of 6 mm, and an outer diameter of 45 mm.
mm.

It is in the form of a forest with a height of 23 +++ ms and an internal volume of 13 cc.

In FIG. 3, the reference numeral indicates a resistance, and in the example, the apparatus was operated with the resistance set to OΩ, that is, with no resistance. During vapor deposition or ion blating, the substrate (4) is kept at room temperature ~
The temperature is about 100°C.

To explain the operation of the device of the present invention with reference to the embodiment shown in the third figure, the inside of the vacuum chamber (1) is evacuated to 10-3 Torr or less,
200 to 300 SCC of Ar gas is supplied from the plasma generation gas source to the hollow cathode electron gun (8) through the gas introduction hole.
Introduced at a flow rate of H, and the pressure in the vacuum chamber was 0.01 to 0.0.
When the temperature reaches 5 Torr, the hollow cathode electron gun (8), the hearth (5) and the auxiliary anode (
A voltage in which a high frequency voltage generated by the high frequency voltage generator iQ 5 (11) is superimposed on a DC voltage of, for example, 80 to 100 volts is generated between the high frequency voltage generator iQ 5 (11) and the high frequency voltage generator iQ 5 (11). In this way, the gas introduced into the hollow cathode (9) excited by the superimposed high-frequency voltage is ionized and becomes plasma, and due to the action of the DC voltage, the ions in the plasma impact the inner wall of the hollow cathode, making it incandescent. , electrons in the plasma become plasma electron beams (15a) (15b) from the hollow cathode tip opening and fly toward the auxiliary anode (19) and the hearth (5).

If the material to be heated (6) is a dielectric or an insulator, in the initial stage of heating, even when irradiated with one plasma electron beam (15a), the temperature does not rise sufficiently, so it becomes negatively charged and the plasma The electron beam (15a) will receive a repulsive force due to its electrification, but the heat-resistant conductive material (Ie coating part (16a)) will come into contact with the surface of the heated material (6) and cover the surface closely. Since the coating part (IGa) is electrically connected to the water-cooled copper hearth (5) via the lead part (1i), secondary electrons from the material to be heated (6) by the plasma electron beam (15a) are Static neutralization by radiation, charge movement, and local discharge is promoted, and the plasma electron beam (
15a) and start heating, the material to be heated (6
) becomes less charged, and as a result, the repulsive force against the plasma electron beam is gradually reduced, and the plasma electron beam (15a) becomes more and more effectively heated material (6).
).

The plasma electron beam (15a) irradiates the material to be heated (6) and at the same time irradiates the heat-resistant conductive material (IO);
) before heating and raising the temperature. Therefore, the conductive material (′
The material to be heated (6) near the covering part (IGa) of the IO is
0 Direct irradiation of plasma electron beam 81 and coating (IGa)
The temperature rise is accelerated because the temperature is increased by both the heat generation and the heat generation.

Within a few minutes after starting irradiation with the plasma electron beam (15a), the temperature of the heated side rises sufficiently, and a stable group 7 is generated between the hollow cathode electron gun (8) and the hearth (5). ,
It is maintained. Even after stable discharge occurs, the covering part (16
Since the electric charge can escape to the water-cooled copper hearth (5) through a), charging can be avoided even if there are places on the surface of the heated material (6) where the temperature is slightly low. After a stable discharge occurs between the plasma electron gun (8) and the hearth (5), the material to be applied (6) is ZnS, PbF2, etc.
? If the material is conductive even without R, it can be evaporated directly from the water-cooled copper hearth (5) at a sufficiently high evaporation rate by irradiating it with a plasma electron beam (15a) as shown in FIG.

ZnS % Mg'2, CeF3, CaF2, TlO2
For heated materials (6) such as, as shown in FIGS. 5 to 8, these heated side slopes (6) are made of W, Ta, Mo.
It is easier to heat and evaporate the material by filling it in a container (5a) made of a metal with a high excitation point such as and irradiating it with a plasma electron beam.

In the case of FIGS. 5 to 8, the plasma electron beam (15a) mainly irradiates the material to be heated (6) and the conductive material (the covering part (16a) of the IO), and partially irradiates the container (5a) and the water-cooled copper. Irradiate the hearth (5) or water-cooled copper block (7).

Therefore, the handle material to be heated (6) and the covering part (IGa) are heated to a high temperature, but the container (5a) is heated to a high temperature.
) Or, since it is in contact with the water-cooled copper block (7), the temperature does not rise much. Since the covering part (16a) uses a high melting point metal such as W, Ta, No, etc., the material to be heated (6)
Even if it reaches the evaporation temperature, the coating part (16a) can be prevented from reaching the evaporation temperature, so the amount of these high melting point metals that make up the conductive material (161) mixed into the deposited film is practically limited. It is possible to reduce it to a negligible level.

When the heating and vapor deposition process of the material to be heated (6) is completed and the heating by the plasma electron gun is temporarily stopped, and then the heating is restarted, the temperature of the material to be heated (6) has completely returned to room temperature. It is easy to restart heating, and the higher the temperature of the material to be heated (6), the shorter the addition time until stable discharge starts.

In the example shown in Figure 3, the plasma electron gun (8) and the hearth (
5) Adjust the distance to the top surface by 200 to 300 strokes and press the material to be heated (
The height from 6) to the substrate (4) can be set to 420 to 500 mm, and the heated material (6) made of oxide
When performing evaporation of
Oxygen gas is introduced at a flow rate of 0 to 140 SCCM. In addition, when performing ion blating, activate the substrate bias DC power supply (I3) and apply zero voltage to the substrate holder (3).
Applying a potential of ~500V and opening the shutter aΦ, ion blating is performed on the glass or metal substrate (4), and when the film formed on the substrate (4) reaches a predetermined thickness, Close shutter a@. substrate(
4) and a current of 0 to IA flows through the substrate holder (3). If the DC power supply 031 is not used, the substrate holder (
3) and the substrate (4) are electrically suspended.

The film thickness and deposition rate on the substrate during vapor deposition or ion blating are measured by recording the change in transmittance at a wavelength of 550 nm on a recorder using an optical film thickness monitor on the photoelectric side.

The conductive material shown in FIG.
% The lid part (1Gl) is Ta, the outer diameter C is 50 mm,
The height H is 6, the mutual sum of the through holes is 4 m1t = 1, u = 1,
The opening E is 57 mm, and the volume of the covering part (16a) is 3.4.
In the case of 3cc, hollow cathode electron gun (8) and Haas (
The power value required to generate a stable discharge between the time becomes shorter. Product of this power and time (required power amount)
The smaller the , the more stable the discharge will occur in a short time for the same power value, and the more advantageous it is that the discharge can be generated with a smaller power for the same time, but in the conductive material aO of the above shape, The required power amount was as low as 0.5 to 2.5 KW/hr. Moreover, the smaller the L of the through-hole part of the covering part (16a), the smaller the required power amount, and the vertical is IO+++++
When the value exceeds n, the antistatic effect of the conductive material ae on the heated material becomes weaker. Even if the volume or heat capacity of the covering portion (IGa) is too large or too small, the amount of power required tends to increase. In addition, the higher the temperature at which the heated forest material (6) becomes conductive, the greater the amount of power required and the longer it takes for stable discharge to occur, and the higher the evaporation temperature of the heated material (6), The amount of power required increases. The conductive materials shown in FIGS. 5 to 8 (IO) showed the same tendency as the conductive material shown in FIG. 4.

In general, a relatively stable discharge tends to occur with PbF2 and ZnS, whereas stable discharge tends to become less likely to occur in the order of MgFz, CeF3, CaF2, and TiO2.

In Figure 3, the board (4) is 127 with a board thickness of 2 +nn+.
Using a blue plate glass substrate and a Pyrex glass substrate of X127 mIm, we measured the deposition rate after stable discharge, and found that for ZnS it was ↓00 to 250 nm/min at a power of 2 to 4 Kw, and for SMgF2 it was 4 to 7 Kw.
50-200nm/min, CeF3 is ~4Kw
at 70-80 nm/min.

CaF2 is 4.5-6.5KW and 50-13Or+m/
It was min.

ZnS s PbF2 could be charged into a water-cooled copper hearth and evaporated.

ZnS deposited by the apparatus of the present invention has a film thickness of 1000 to 3
000r+m, the optical constant in the visible range is approximately 2.
It was 2-0.002j. In addition, MgF2 has a film thickness of 16
00 to 330 (in the case of lnm, the optical constant in the visible range is approximately 1
, 350.003i. Further 1100-1300
CeF3) formed to a film thickness of nm has an optical constant of approximately 1.60.
-0.002+, the optical constant of CaF2 formed to a film thickness of 500 to 2000r++1 is approximately 1.45-0.03
It was j.

The plasma electron beam heating device of the present invention can be used for melting not only dielectric materials but also ceramics.

The conductive +a' ae covering portion (16a) is not limited to a disk shape, and may be a prism, a cone, or a pyramid, or may have a part thereof protruding vertically and horizontally. The conductive material 00 is a high melting point metal such as Re, Nb, ILF, graphite, a boron nitride type conductive compound, or a high melting point conductor whose main component is a high melting point material, a high melting point metal, or a conductive compound. It is also possible to use a conductive material (alumina or other insulating ceramic for a part of the IO).

Lead part (IGfri plasma electron beam light AJ m
A conductive material with poor heat resistance, such as copper, can be used in areas where there is little heat resistance.

The shape of the covering part (IGa) may be in the form of a drainboard or a fiber, in addition to the illustrated embodiment, and the constituent members of the covering part (16a) are not in a fixed state but in contact with each other. You can.

(Effects of the Invention) As described above, in the present invention, a heat-resistant conductive material is provided in contact with the material to be heated so as to cover the opening of the hearth or container, and the charging of the side material to be heated is prevented. This allows the plasma electron beam to escape into the hearth or container, which reduces the charge-up of the material to be heated and reduces the deviation of the plasma electron beam from the side material to be heated. It can be used for heating, and a stable discharge can be formed between the hollow cathode electron gun and the hearth or container in a short time without supplying large amounts of power, stabilizing the heating and evaporation of the added FA44 material. Even if the hollow cathode electron gun and the hearth or container are far apart, the electron gun and the hearth or container filled with a non-conductive material such as an insulator or dielectric can be used. It is possible to easily and reliably generate a stable discharge between the The probability of collision with evaporated matter, Ar, and reaction gas increases, improving ionization efficiency, and the diameter of the plasma electron beam is appropriately spread over the surface of the material to be heated, allowing uniform heating. It has the advantage that undesirable thermal decomposition of the material can be suppressed, and the device is relatively simple and can be manufactured at low cost.

[Brief explanation of drawings]

1 and 2 are schematic sectional views of a conventional plasma electron beam heating device, FIG. 3 is a schematic sectional view of an embodiment of the present invention, and FIGS. 4 to 8 are schematic sectional views of a conventional plasma electron beam heating device. FIG. 3 is an enlarged cross-sectional view of the main part of the embodiment. <1)...Vacuum chamber (4)...Substrate 8 (5)...Water-cooled copper hearth (5ζ1) Volume (6)...Heated month 1l-1 (8)...Hollow cathode electron; °,・(15a)・
・Plasma electron beam qO...conductive O1' (IGa) (16j
2) Lead part

Claims (5)

[Claims] 1. A plasma electron beam from a hollow cathode electron gun connected to a DC power source is irradiated onto a material to be heated stored in a hearth or a container to heat the material, and A conductive material using a heat-resistant conductive material is provided so as to cover the hearth or the container, and the conductive material is electrically connected to the hearth or the container so that the electrical charge of the heated material generated by the irradiation of the plasma electron beam is transferred to the hearth or the container. A plasma electron beam heating device characterized by escaping into a container. 2. The plasma according to claim 1, wherein the conductive material is provided with a large number of mesh-like or other through-holes having an average size of less than 10 mm on a surface that contacts and covers the heated material. Electron beam heating device. 3. The heat-resistant conductive material includes a high-melting point material such as graphite, a high-melting point metal such as W, Ta, Re, Mo, Nb, and Hf, a boron nitride-based conductive compound, TaC, and Ti.
A claim characterized in that the material is a high melting point conductor whose main component is a conductive compound such as C, W_2C, ZrC, and TaB_2, or a high melting point material thereof, a high melting point metal, or a conductive compound. 1. The plasma electron beam heating device according to 1. 4. 2. The plasma electron beam heating apparatus according to claim 1, wherein the hearth is a water-cooled copper hearth. 5. The container is made of a high melting point material such as graphite, W, Ta.
, Re, Mo, Nb, Hf and other high-melting point metals, boron nitride-based conductive compounds, TaC, TiC, W_2C
, ZrC, TaB_2, etc., or a heat-resistant conductive material whose main component is these high-melting point materials, high-melting point metals, or conductive compounds, and the container is in contact with a water-cooled hearth or a water-cooled copper block. The plasma electron beam heating device according to claim 1, characterized in that: