JPS59200758A - Vapor deposition device - Google Patents

Abstract

PURPOSE:To provide a vapor deposition device which is capable of forming a film deposited by evaporation with good quality by installing an electric discharging means for ionizing and/or activating the gas for reaction to be supplied into a vapor deposition vessel via an attaching member which is adjustable in position with respect to the wall part of the vapor deposition vessel. CONSTITUTION:The inside of a bell-jar (vapor deposition vessel) 30 is preliminarily evacuated to, for example, 10<-5>-10<-7> Torr. A substrate 2 disposed in the bell-jar 30 is heated 34 to <=600 deg.C, more particularly <=300 deg.C and while the activated and/or ionized gas for reaction is introduced 36 into the bell-jar 30, an evaporating material is evaporated by heating from an evaporating source 25 disposed to face the substrate 2, thereby forming a film on the substrate 2. A gas discharger 37 is installed in the bell-jar 30 via an attaching plate 39 which is adjustable in position with respect to the wall part of the bell-jar 30. More specifically, the formation of the uniform film on a large area is made possible by providing at least one gas discharger adjustable in position in the vapor deposition vessel.

Description

DETAILED DESCRIPTION OF THE INVENTION 1. Field of Industrial Application The present invention relates to a vapor deposition apparatus configured to perform vapor deposition by introducing a reaction gas into a vapor deposition tank, and particularly to an apparatus called a reactive vapor deposition apparatus. It is something.

2. Prior art This type of reactive vapor deposition apparatus is, for example, I To (Indi
When forming a transparent conductive film consisting of umTin Oxide), in the presence of ionized or activated oxygen gas, an In-Sn alloy and/or its oxide is released from the To tablet, or In and Sn and/or The respective oxides can be deposited onto the substrate by binary evaporation.

D, C, ion blating devices, and RF ion brating devices are known as reactive vapor deposition devices. Among these, RF ion brating using high frequency discharge is disclosed in Japanese Patent Application Laid-open No. 50-84474 and Japanese Patent Application Laid-open No. 49
-113733 and Japanese Unexamined Patent Publication No. 49-120877. For example, as shown in FIG. 1, the substrate 2 is heated with a heater 34 in a vacuum chamber (Pelger) 30, and a predetermined voltage (
-10V to -10kV) 35 is applied, while an AC voltage 6 is applied to the coil electrode 5 (high frequency discharge electrode) arranged on the evaporation source 25.Although the frequency of the AC is arbitrary, a high frequency (for example 13. 56 Mllz),
Good discharge stability. ), thereby the substrate 2-electrode 5
The resulting glow discharge activates or ionizes each atom of the unactivated reaction gas from the inlet tube 36 together with the vapor of the evaporated substance, thereby depositing, for example, an ITO film on the substrate 2.

However, the above-mentioned known devices are mainly described below [11
It was found that there were fatal defects as shown in (4).

(1) Since high-frequency discharge is stably performed in a low vacuum of the order of 10' to 10-4 Torr,
' At a high degree of vacuum on the order of Torr, the discharge becomes unstable and it becomes difficult to perform reactive vapor deposition. Therefore, in order to increase the adhesion strength of the deposited film and make the deposited film dense,
It is necessary to apply a high voltage to the substrate to be evaporated to accelerate the evaporated material with an electric field. However, when depositing on an insulating substrate, such as a glass or plastic substrate, it is difficult to provide a voltage applying means.

(2) Because there are many cases where evaporated substances are deposited on the high-frequency discharge electrode, when film formation is performed for a long time, the evaporated substances attached are bombarded and peeled off by the discharge, which causes the discharge to become unstable. Alternatively, it may get mixed into the evaporation source, making the deposited film non-uniform.

In addition, evaporated substances may adhere to the high frequency introduction terminal, causing high JA-1
Caused by wave leakage.

(3) In order to perform uniform MB'A on a large area substrate,
It is necessary to expand the high-frequency discharge electrode and the discharge area. As a result, it becomes a source of noise that causes malfunction of electrical components installed in the deposition tank.

(4) When the evaporation rate of the evaporated substance changes, the discharge becomes unstable and the film quality becomes non-uniform.

By doing so, we have discovered a device that can solve all of the problems mentioned above, and have arrived at the present invention. .

4. Structure of the invention and its effects In the vapor deposition apparatus, the gas discharge means for ionizing and/or activating and supplying the reaction gas is attached to a member whose position can be adjusted with respect to the wall of the vapor deposition tank. The present invention relates to a vapor deposition apparatus characterized in that the vapor deposition apparatus is installed inside the vapor deposition tank via the vapor deposition tank.

The device of the present invention has the following features (
It has excellent characteristics such as 1) to (4).

(1) The reaction gas is introduced from the gas inlet and an inlet tube is provided in the discharge section, and a discharge can be generated in the inlet tube by the discharge electrode around the inlet, so that the gas pressure in the discharge area is can be maintained higher than the gas pressure in the space inside the deposition tank. Therefore, high-frequency discharge can be performed stably, and electric field acceleration of the evaporated substance is not required to lower the gas pressure in the space inside the vapor deposition tank to reduce iM, making it possible to form a high-quality vapor deposited film.

(2) Since the discharge electrode can be installed around the gas introduction tube, the gas in the introduction tube with high gas pressure can be efficiently ionized or It can be activated and sent to a calming space. For this reason, ionized or activated gas components can be efficiently incorporated into the deposited film.

(3) Gas discharge occurs within the gas introduction tube, and the discharge electrode and high frequency introduction terminal can be isolated from the discharge area, so bombardment by gas ions does not occur, and heating of the electrode material and evaporation due to bombardment, and film forming space can prevent contamination.

(4) By providing at least one discharge device in the vapor deposition tank so that its position can be adjusted, uniform film formation over a large area becomes possible.

5. Examples Hereinafter, the present invention will be explained in detail with reference to the drawings.

FIG. 2 shows a reactive vapor deposition apparatus according to this example. That is, a vacuum pump (not shown) is connected to the Pel jar 30 forming a vacuum chamber via an exhaust path 38 having a butterfly valve 32, and thereby the inside of the Pel jar 30 is preliminarily heated to a pressure of, for example, 10-5 to 10" Torr. Keep it in a high vacuum state.

The substrate 2 is placed inside the bell jar 30 and heated to a temperature of 600°C or less, preferably 300°C by a heater 34.
Gas inlet 36 (see Figure 3)
While introducing the activated and/or ionized reaction gas into the Pelger 30 by a gas discharge device 37 (described in detail later) connected to the Pelger 30, the gas pressure is I x 10=
~8 x 10 Torr), the evaporation material is heated and evaporated from the evaporation source 25 disposed in the Herjar 30 so as to face the substrate 2.

This heating means is an electron beam 2 produced by an electron gun heating device 26.
7 or a resistance heating method may be used. Further, a negative bias voltage 35 can be applied to the substrate 2 (actually, its back electrode (not shown)) as necessary.

What should be noted here is that the gas discharge device 37 is
It is constructed as clearly shown in FIG.

That is, for installation, a through hole (inlet) 40 is formed in the center of the plate 39 and is connected to the gas inlet 36.
A ring-shaped projection 41 with a small diameter and a ring-shaped projection 42 with a large diameter are provided concentrically around the 0.

A gas introduction pipe 43 is removably fitted and fixed to the inner protrusion 41 so as to wrap around it, and a cylindrical anti-stick part 44 is similarly fitted to the outer protrusion 42. Fixed. For example, a coil-shaped discharge electrode 45 is wound between the outer circumference of the introduction tube 43 and the inner circumference of the adhesion prevention member 44 . A common ring plate 46, which constitutes a part of the deposition prevention member, is fixed to the inner end surfaces of the introduction pipe 43 and the deposition prevention member 44 with screws 47, so that the introduction pipe 43 and the deposition prevention member 44 are connected to each other for discharge. Installation with the electrode 45 contained is method Slope 3.
Attached to 9. However, various mounting methods or orders may be considered, and the ring plate 46 may be fixed in advance as described above and then fitted into the projections 41 and 42 at the same time.

For installation, a high frequency introduction terminal 48 connected to one end of an electrode 45 is fitted and fixed on the front side of the plate 39, and a gas introduction pipe 50 from the outside is screwed and fixed in the center part through a threaded part 49. be done. Also, the installation is done using the plate 39 and anti-fouling member 44.
There is cooling water 70 around them to prevent them from heating.
Water-cooled pipes 71, 72 are provided for passing the water. Also, electrode 4
It is also possible to introduce cooling water into the interior of 5. The water cooling tubes 71, 72 may be separate pieces or may be integrated with each other at appropriate points.

Then, for installation, the plate 39 is screwed into the screw hole 51 on the periphery.
2, it is removably fixed to the installation stand 53 inside the Pelger 30. A notable configuration here is that an installation base 53 on which the above-mentioned high-frequency gas discharge device 37 is removably fixed via a plate 39 is fixed to the bottom wall 30a of the Pelger 30 so that its position can be adjusted. This allows the discharge device 37 to be properly installed at any position within the herger 30. For this purpose, for example, a screw hole 73 in the bottom wall 30a of the herger is required.
The mounting base 53 may be fixed to the Pelger wall by forming an appropriate number of screws at appropriate positions and screwing screws 74 into the screw holes 73. Therefore, the arrangement of the discharge device 37 is as follows:
The fixing position of the installation base 53 by the screws 74 can be arbitrarily adjusted, for example, it can be moved in the direction 75 shown by the imaginary line.

Correspondingly, the container pipes 50, 71, 72, etc. may be loosened by a predetermined length in advance and configured as a visible pipe.

The above-mentioned discharge device 37 is configured as a coupling type (inductively coupled type) using a coil electrode 45, and ions or activation components of the reaction gas generated in the gas introduction tube 43 by application of a high frequency voltage are released. The evaporated substance 25 is led out from the opening 56 into the inner space of the Pelger 30 (ie, the flight space in which the evaporated substance 25 flies toward the substrate 2).

To explain a specific example of the configuration of this reactive vapor deposition apparatus, first,
In the leaving device 37, the gas introduction pipe 43 is made of an insulating material,
For example, it is made of a highly heat-resistant ceramic material such as a quartz or pyrex glass tube, an alumina tube, a SiC sintered tube, or a tube made of BN (boron nitride) with an inner diameter of 2 to 10 cmφ. The discharge electrode 45 is formed as a metal antenna wound around the introduction tube 43, and is, for example, a stainless steel pipe wound up into a spiral circle with an inner diameter of 5 cm to 20 cm (in this case, the electrode is connected by passing cooling water through the pipe). It can be water-cooled from the inside). The material may be copper or platinum. In addition, the introduction of high frequency
After passing through a matching circuit (not shown) outside the Pelger, it is introduced into the Pelger through the introduction terminal 48. The other end of the electrode 45 is a free end.

The adhesion prevention member 44 (further 46) covers the introduction tube 43 and the electrode 45, prevents evaporative substances from adhering to these and the high frequency introduction terminal 48, and prevents leakage of high frequency power to stabilize discharge. It was established for the purpose of
For example, it is made of a metal plate such as stainless steel.

The introduction pipe 50 is made of stainless steel or copper, and the reaction gas introduced through this pipe is oxygen, nitrogen, hydrogen, methane, propane, etc. depending on the type of deposited film.
It is possible to use a small amount of silane, phosphine, diborane, arsine, etc. or/and a mixed gas with an inert gas such as argon.The evaporated substances (25 in Figure 2) include tungsten, molybdenum, chromium, etc. , iridium, tantalum, titanium, nickel, indium, tin, indium-tin alloy, aluminum, silicon, oxides and nitrides thereof, etc. For example, in the rTOIIWO fold film, indium −
Tin alloy and/or its oxide, or iodium and tin (separately arranged for binary evaporation) (introduced gas is oxygen alone or oxygen + Ar), silicon or aluminum and/or tin for nitride film formation. or its nitride (introduced gas is N)
2 or N2+Ar), amorphous hydrogenated silicon (a
-5i:H) Silicon (4 gases are hydrogen or H, k + Ar) may be used as an evaporation substance. For example, when using a mixed gas of oxygen and argon as the introduced gas, oxygen (flow rate 30 cc/min)
, when introducing argon gas (flow rate 5 Qcc/min), the degree of vacuum in the evaporation space inside the Pelger 30 is 10-
Maintain the pressure on the order of 5 to 10 Torr and insert the inlet pipe 43.
Stable high-frequency discharge within (introduced high-frequency power is OW~3KW)
) can be caused. The relationship between the degree of vacuum in the deposition space and the degree of vacuum in the introduction tube 43 can be arbitrarily adjusted by changing the flow rate of the introduced gas, the flow rate of the exhaust gas, the area of the gas discharge opening 56, and the like. The area of the gas discharge opening 56 is, for example, 5 to 30 cm! It is desirable that

A reactive vapor deposition apparatus equipped with the gas discharge device 37 as described above is as follows:
Compared to conventional devices, this device has the following features (1) to (6).

(1) By arranging the gas introduction pipe 43 close to the introduction port 36 (or 40), the gas pressure in the discharge region 57 can be maintained higher than the gas pressure in the deposition space, resulting in stable high frequency Discharge becomes possible.

Moreover, since the ions generated in the introduction tube 43 can be immediately introduced into the Pelger through the discharge opening 56, the amount and efficiency of introduction can be increased. Furthermore, the gas pressure in the deposition space can be reduced, making it unnecessary to accelerate the evaporated substance in an electric field, allowing a wide range of materials to be selected for the substrate to be deposited, and making it possible to form a high-quality deposited film.

(2) By arranging the discharge electrode 45 around the outer periphery of the introduction tube 43, the gas pressure in the vapor deposition space can be prevented from increasing.
The gas in the introduction tube 43, which maintains a high gas pressure, can be efficiently ionized or activated. In addition, since the gas discharge region is limited within the discharge tube 43 and isolated from the electrode 45, the electrode 45 can be prevented from being bombarded by gas ions generated during discharge. In other words, it is possible to prevent the electrode material from being heated or evaporated by bombardment, thereby preventing contamination of the deposition space.

(3) Since the adhesion prevention members 44 and 46 were provided so as to enclose the introduction tube 43 and the electrode 45, the introduction tube 43, the electrode 45,
It is possible to prevent evaporated substances from adhering to the high-frequency introduction terminal 48, and also to effectively prevent leakage of high-frequency waves through the mounting plate 39, electrode 45, and introduction tube 43, so that discharge can be performed stably.

[4) Since the gas discharge device 37 can be installed in the Pelger 30 via the installation stand 53 with a simple structure, installation or removal work becomes easy. Furthermore, when forming an M film on a large-area substrate, uniform film formation is possible by adjusting and optimizing the installation position and number of M films. For example, set the discharge device in the appropriate position, or evenly!
Multiple pieces can be set for M membrane.

(5) Since the direction of the gas discharge port can be easily changed, it can be set so that the discharge is not disturbed even when the evaporation rate changes. In particular, if the gas discharge device is set so that the gas discharge port is not directed between the evaporation source and the substrate, the discharge will continue stably.

(6) By cooling the mounting base 53, discharge electrode 45, and adhesion prevention member 44 with water-cooled tubes 71 and 72, heating during discharge can be prevented, high-power radio frequency waves can be introduced, and reactive vapor deposition can be promoted.

In Fig. 7, unlike the above example, the discharge electrode is connected to the introduction tube 4.
A plurality of rings 45a arranged so as to enclose a circumferential surface of 30
, 45b (however, the above-mentioned water cooling pipe is omitted from the illustration for the sake of brevity). Among these, one ring-shaped electrode 45a is connected to the high-frequency introduction terminal 4 through a lead wire 67, and the other ring-shaped electrode 45b is connected to the metal anti-corrosion member 44 through a lead wire 58. It is grounded via a single plate 39. The electrodes 45a and 45b are made of copper, stainless steel, or a platinum layer band ring with an inner diameter of 2 to 10CIIIφ and a width of 0.5 to 1Qcm, and generate a C-coupling type (capacitive coupling type) discharge in the introduction tube 43. urge By wrapping a water-cooled tube around the band ring and cooling it, high-power and high-frequency waves can be introduced for a long period of time.

Next, an actual reactive vapor deposition apparatus using the above gas discharge apparatus 37 will be explained with reference to FIGS. 8 to 10.

However, parts common to the above-described example are given common reference numerals, and their explanations may be omitted.

Two gas discharge devices 37 similar to those described above are installed in the health jar 30 as an empty tank, while a sheet 2 as a substrate to be evaporated placed facing the evaporation material 25 is fed from a supply roll 59. It is sent to a take-up roll 60. Both rolls are provided with anti-stick plates 61 and 62, respectively. The male outlet of each discharge device 37 is arranged so as not to point toward the region 66 between the evaporation source 25 and the substrate 2 . The substrate 2 has a reflective plate 65 arranged behind it through a wire mesh 63.
Heater (e.g. halogen lamp heater) 34
is heated evenly. Further, a negative bias voltage is applied to the substrate 2 or the back electrode (an electrode plate provided behind the substrate) as necessary. Further, a film thickness meter (for example, a known crystal monitor) 64 for controlling the thickness of the vapor deposited film formed on the substrate 2 is arranged.

Such a deposition apparatus can be operated under the following conditions.

Evaporation material 25: ITO Tabreso) (Sn 5% by weight) Evaporation method: Electron gun heating Deposition substrate 2: Metal sheet or resin (e.g. polyethylene terephthalate) sheet Temperature of deposition substrate 2 from 0 to 300°C Introduced gas: Oxygen gas ( 30cc/min) and argon gas (50cc/min: to keep the amount of oxygen constant and adjust the degree of oxidation by oxygen). The flow rate can be controlled individually.

High frequency discharge device 37: High frequency power 50W to IKW shown in FIG. 3 or FIG. While being introduced into the substrate, ITO 25 was heated with an electron gun to evaporate it, reacted with the introduced gas ions or active force components, and was deposited on the substrate 2. As a result, the evaporation rate of the evaporation material was set at 100-2000X/min, and the conveyance speed of the substrate was set at 50-2000X/min.
When G was set to 200 cm/min, an ITO film with a sheet resistance of 500 Ω/cot to IM Ω/cf and a light transmittance of 80 to 90% could be uniformly formed on the substrate.

Further, in the vapor deposition apparatus shown in FIG. 8, two gas discharge devices 37 are arranged in the herger, and the gas discharge ports are not directed between the evaporation source 25 and the substrate 2. The conditions in this case were as follows.

Evaporation rate 25:In ($; rate of onset 10 to 5 people/sec
>, Sn (evaporation rate 0.5 to 0.2 people/5 ec) Evaporation method: Resistance heating (binary evaporation) Deposition target substrate 2: 1 m wide resin (e.g. biaxially oriented polyethylene terephthalate) sheet, thickness 125 μm Temperature of substrate 2 to be evaporated: 50 to 80'C Introduced gas: Oxygen gas (45 cc/min) Degree of vacuum:
5 X 10 = Torr High-frequency discharge device 37: 2 units of the type shown in Fig. 7 (equipped with water-cooled tubes of the type shown in Fig. 5) Introduced power: IKW ~ 500 W In other words, oxygen is ionized or activated by discharge in each discharge device 37. Each evaporation source was heated and evaporated while being introduced into the evaporation space in the bell jar 30, and the introduced force was reacted with ions or active gas components to evaporate onto the substrate 2JJ. When the conveyance speed of the substrate 2 is 1 to 2 m/min, on the substrate there are sea 1-resistance 3QQ r2/ci~IMΩ/CLd,
It was possible to uniformly form an ITO film with a light transmittance of 80 to 90%.

Note that the above vapor deposition apparatus was also capable of forming a film at a low temperature of 50°C. As a result, it was found that an ITO crotch can be formed satisfactorily even on a polyethylene terephthalate film (-axis stretched) required for LCDs (liquid crystal display devices).

Although the present invention has been illustrated above, the above-mentioned example can be further modified based on the technical idea of the present invention.

For example, a plurality of the above-mentioned gas introduction pipes 43 can be provided, and as shown in FIG. The introduction tubes 43 may be arranged side by side, and the introduction tubes 50 may be connected to each of them, and the common strip electrodes 45a, 45 may be wound and attached. This is advantageous because the ionized or activated gas components can be more uniformly distributed on the deposition surface of the substrate 2.

Further, the gas distribution can be arbitrarily adjusted depending on the arrangement of the gas introduction pipe. Further, the shape of the gas introduction pipe, including the gas introduction pipe, may be rectangular or the like other than circular. Furthermore, the position and structure of the mounting location (particularly the above-mentioned installation stand) and the method of mounting the gas discharge device to the herger can be modified in various ways. The number of gas discharge devices can be three or more, and the arrangement can be such that gas is uniformly supplied depending on the groups Fj and f. Note that the present invention is applicable not only to the above-mentioned high-frequency gas discharge device but also to a vapor deposition device for growing other gas discharge devices.

[Brief explanation of the drawing]

2 to 11 show embodiments of the present invention; FIG. 2 is a schematic cross-sectional view of a reactive vapor deposition device; FIG. 3 is an enlarged cross-sectional view of a gas discharge device and its installation; Figure 4 is a side view of the gas discharge device viewed from the gas introduction side, Figure 5 is a perspective view of the gas discharge device, and Figure 6 is an exploded view of the gas discharge device (the same frequency discharge electrode and water-cooled tube are omitted). 7 is a perspective view of another gas discharge device, FIG. 8 is a schematic sectional view of an actual reactive vapor deposition device, FIG. 9 is a view from the X Y in figure 8
11 is a perspective view of another gas discharge device. In addition, in the reference numerals shown in the drawings, 2...... Vapor deposition target substrate 25... Evaporation material 26... Electron gun 30... ...Hoelscher 34...Heater 36.40...Gas inlet 37...
......Gas discharge device 39...Mounting plate 41.42...Protrusion 43...Gas introduction pipe 44.46 .61.62... Adhesion prevention member or adhesion prevention plate 45.45a, 45b... Discharge electrode 48.
......High frequency introduction terminal 53...
- Installation stand 56... Gas discharge opening 57... Discharge area 59... Supply roll 60... Take-up roll 64... Film thickness gauge 65... Reflection plate 66... Vapor deposition space 71.72... ...Water cooling pipe 73...Screw hole 74...Screw. Agent Patent Attorney Hiroshi Aisaka (1 person) No. 31 Hasu No. 41 No. 81 No. 91 Liu No. 101 ￥l 喰11

Claims (1)

[Scope of Claims] 1. In a vapor deposition apparatus configured to perform vapor deposition by introducing a reaction gas into a vapor deposition tank, a gas discharge means for supplying the reaction gas after ionizing and/or activating the reaction gas. The vapor deposition apparatus is characterized in that the attachment whose position can be adjusted with respect to the wall of the vapor deposition tank is installed inside the vapor deposition tank via a member. 2. The device according to claim 1, in which at least one high-frequency gas discharge device is installed as gas discharge means. 3. The device according to claim 1 or 2, wherein the mounting member is an installation stand that can be attached to and detached from the wall of the steam MPfl. 4. According to any one of claims 1 to 3, wherein the gas discharge port of the gas discharge means is arranged so as not to point toward the area between the evaporation source and the substrate to be deposited. Equipment described. 5. The gas discharge means has a gas introduction tube that guides the reaction gas from the gas introduction port to a predetermined location in the vapor deposition tank, and a discharge electrode arranged around the gas introduction tube. An apparatus according to any one of claims 1 to 4. 6. The device as set forth in claim 5, wherein the gas introduction tube and discharge electrode of the gas discharge means are provided with an adhesion prevention member for preventing evaporated substances from adhering thereto. 7. The device according to claim 5 or 6, wherein the gas introduction pipe is made of an insulating member. 8. The device according to any one of claims 5 to 7, in which a plurality of gas introduction pipes are provided and a reaction gas is introduced into these pipes. 9. The device according to any one of claims 5 to 8, wherein at least one discharge electrode is arranged. 10. The device according to any one of claims 5 to 9, wherein the discharge electrode is a metal antenna wound around a gas introduction tube. 11. The device according to any one of claims 5 to 9, wherein the discharge electrode is composed of a plurality of ring-shaped metal electrodes arranged so as to enclose the circumferential surface of the gas introduction tube. . 12. The device according to claim 1, wherein the gas discharge means is attached within the vapor deposition handle in a removable manner to the member. 13. The apparatus according to claim 12, wherein the gas discharge means is detachably attached to a member within the vapor deposition tank via a plate. 14. The device according to claim 13, wherein a gas inlet is provided in the plate, and a gas inlet pipe is fixed so as to surround the gas inlet. 15. The device according to claim 14, wherein the gas introduction pipe is removably fitted and fixed to a protrusion provided on the plate. 16. The third aspect of claim 1, wherein the adhesion prevention member for preventing evaporative substances from adhering to the gas introduction tube and the discharge electrode is removably fitted and fixed to a protrusion provided on the plate. 1
The apparatus described in any one of Items 3 to 15. 17. The gas discharge means is attached to the plate in order to prevent heating of the plate, and the plate is provided with a cooling means, as described in any one of claims 13 to 16. Device. 18. The device according to any one of claims 6 to 17, wherein the deposition preventing member is provided with a cooling means in order to prevent the deposition preventing member from being heated. 19. The device according to claim 17 or 18, wherein the cooling means is a water-cooled pipe.