EP1743050A2

EP1743050A2 - Thermal vacuum deposition method and device

Info

Publication number: EP1743050A2
Application number: EP05736229A
Authority: EP
Inventors: Lutz Gottsmann; Ulf Seyfert; Bernd-Dieter Wenzel; Reinhard JÄGER
Original assignee: Von Ardenne Anlagentechnik GmbH
Current assignee: Von Ardenne Anlagentechnik GmbH
Priority date: 2004-04-27
Filing date: 2005-04-16
Publication date: 2007-01-17
Also published as: WO2005106072A2; KR20070005004A; JP2007534843A; DE102004041854B4; DE102004041854A1; WO2005106072A3; KR100835044B1; US20070240636A1; CN1950535A; CA2564256A1; CN1950535B

Abstract

The invention relates to a thermal vacuum deposition device and method in which a band-shaped substrate is continuously conveyed in a vaporization channel that is charged with a vaporous coating material. The aim of the invention is to allow the substrate to be quickly protected against damage during the coating process in previously known deposition methods and devices. Said aim is achieved by the inventive method, which is characterized in that the vaporization channel is sealed by inserting at least one positionally adjustable hollow element into an outer space of the vaporization channel and an inner space of the vaporization channel when a minimum conveying speed is not attained or when the substrate is at a standstill such that the substrate is located in the inner space.

Description

Process and device for thermal vacuum coating

The invention relates to a method and a device for the thermal vacuum coating of a continuously transported substrate by evaporating solid and / or liquid coating materials and vapor deposition of the vaporous coating material on the substrate, the substrate moving in a heated evaporation channel of an evaporation device, the evaporation channel is arranged in a vacuum chamber and is connected to an evaporation device, and the evaporation device and the evaporation device are the essential parts of a coating device.

Various coating methods for physical vapor deposition (PVD) in vacuum are known. The coating systems used for this are differentiated in systems according to a static or a continuous process. In contrast to the static method, a substrate is continuously transported through the coating device in the continuous method. Correspondingly, coating material in the form of steam is fed continuously to the vaporization channel of the coating device.

Such systems are used in particular for the coating of band-shaped steel substrates with a bandwidth on the centimeter scale up to the meter scale. For the economical use of a system according to the continuous coating process, there is a need for the coating device to be continuously stocked with coating material without interrupting the continuous substrate transport. In conventional coating processes, temperatures are used in the vapor deposition channel which are suitable for influencing the mechanical properties of the substrate. For this reason, a precise coordination between the temperature in the vapor deposition channel and the transport speed of the substrate is necessary and must be observed. If there is a disturbance in the transport, for example a reduction in the transport speed or even a standstill of the substrate in the vaporization channel while the surface temperature of the vaporization channel remains the same, the substrate can heat up to the point where it is damaged, and its physical properties can increase up to Change useless. In particular, the tearing of the substrate tape is associated with a considerable amount of time and cost for the repair due to the usual system size and the special process conditions.

It is therefore an object of the present invention to provide, for the known coating methods and coating devices, the possibility of quickly employing protection for the substrate against damage during the coating process, in particular during changing parameters of the coating process, such as, for example, the substrate speed.

The object is achieved in a method according to the invention in that the vapor deposition channel is separated into an outer space and an inner space when the substrate is below a minimum transport speed or when the substrate is at a standstill by inserting at least one position-changing hollow body such that the substrate is located in the inner space ,

Thus, in the case in which the substrate is exposed to the radiant heat of the heated evaporation channel for a longer period than designed, the substrate located in the evaporation channel is thermally protected by the hollow body arranged between the substrate and the hot evaporation channel surface, and the substrate is in such a malfunction no thermal see exposure to stress. With the insertion of a hollow body, very quickly available protection of the substrate is made possible, which can also be automated by means of suitable movement and temperature detection.

Another particular advantage of inserting a hollow body according to the invention into the space between the vaporization channel surface and the substrate is that the vapor-like coating material flowing in, for example, through nozzles in the channel surface essentially flows on the hollow body and not on the substrate separates. In this way, an uncontrolled coating of the substrate in the event of a malfunction can also be prevented. Furthermore, because of the good closure of the substrate with the hollow body inserted, it is possible to close the substrate protection device according to the invention for conditioning the evaporator system, since this can prevent contamination of the layer on the substrate section located within the vapor deposition channel.

In a particularly advantageous embodiment of the method it is provided that two hollow bodies are inserted in a movement directed towards one another and the two end faces of the two hollow bodies directed towards one another lie against one another in the inserted state.

By introducing two hollow bodies in the vaporization channel, comparatively short travels of the hollow bodies are possible, which on the one hand increases the advantage of the quickly available substrate protection and on the other hand reduces the additional space required for the provision of the hollow body in a standby position, especially since the dimensions a steaming system are usually very significant. Also required to move the hollow body force, the expansion means by means of suitable transmission means inside the Bedamp ^¬ can be applied, are significantly reduced. For example, in the usual vertical arrangement Steaming chamber by a corresponding force deflection, the weight of one hollow body can be used to move the other hollow body.

It is also expedient if the hollow body or bodies moves in the vacuum chamber surrounding the vaporization duct. The vaporization channel has an opening on the inlet side for introducing the hollow body. As a result, the hollow body is in the ready position as well as in the use position and in every intermediate position in the vacuum chamber, so that influencing of the process parameters, such as pressure within the vacuum chamber, is avoided. In addition, this embodiment of the invention is suitable for ensuring that the substrate can be protected particularly quickly.

In a further advantageous embodiment of the method, it is provided that the hollow body is inserted parallel to the transport direction of the band-shaped substrate. The hollow body thus rests in the ready position in the immediate vicinity of the vapor deposition channel and is already positioned so precisely in this position relative to the moving substrate that only a parallel displacement of the hollow body is required. The protection of the substrate is thus produced after a simple linear movement of the protective body has been carried out.

In addition, it is useful if the hollow body is cooled using a suitable method, since the heat energy absorbed by the hollow body is thus dissipated. This ensures, in particular, that the vaporous coating material is always deposited on the hollow body while the hollow body remains in the hot vaporization duct and its heating is delayed or even prevented, so that there is no retrograde evaporation of the material deposited briefly on the retracted, relatively cold hollow body he follows. The cooling is therefore particularly preferably carried out actively by means of a cooling liquid. This cooling can be done independently be guaranteed by the duration of the stay of the hollow body in the hot evaporation channel.

To interrupt a further loading of the vaporization channel with vaporous coating material, the loading of the coating chamber with coating material is expediently prevented by closing a valve in the event of a fault. As a result of the interruption of the supply, the vaporous coating material which is already in the vaporization channel and the feed line separates essentially completely on the cold surface of the hollow body pushed into the vaporization channel. Since the remaining surfaces of the vapor deposition channel continue to be heated until the remaining vaporous coating material is essentially completely deposited, the coating material will essentially only deposit on the hollow body.

On the arrangement side, the object is achieved by an inventive device for substrate coating according to the features of claim 7. According to claim 7, when the substrate falls below a minimum transport speed or when the substrate is at a standstill, at least one hollow body which can be inserted into the vapor deposition channel surrounds the substrate. The substrate resting in the evaporation channel is thus thermally protected by the hollow body arranged between the substrate and a heating device. The substrate is thus exposed to lower thermal loads in such a malfunction. In addition, the inflowing vapor-like coating material essentially deposits on the hollow body.

In order to ensure that the operation is as inexpensive as possible and, moreover, reliable, thanks to a one-piece functional element, it is advantageous that the hollow body is a prismatic or cylindrical hollow body. The substrate is for its continuous transport passed through the hollow body, is provided so that through the hollow body a vollumfängli ^¬ cher protective body. In a further special embodiment it is provided that the hollow body during regular, continuous substrate transport with at least the minimum speed in a standby position outside the vapor deposition channel and within the vacuum chamber and, moreover, if necessary, when the substrate is below the minimum transport speed or when it is at a standstill in an operating position is essentially arranged in the vaporization duct. The hollow body can always remain completely arranged in the vacuum chamber and close in the insertion area with the wall of the vaporization duct.

If, in accordance with another embodiment of the coating device according to the invention, two hollow bodies are essentially arranged in an application position in the coating chamber, the hollow bodies form an optically sealed separation into an inner and outer part of the vapor deposition channel, whereby the described advantages with regard to the separation of the vapor deposition channel reinforce the existing substrate and also have the system engineering outlay for the substrate protection device optimized.

The hollow body wall can expediently be made from a high-temperature steel or a high-temperature alloy. In any case, the hollow body wall has sufficient thermal and thus also mechanical stability even in the event of a fault up to a temperature range of 800 ° C., preferably up to 1000 ° C.

In order to achieve thermal insulation of the two spaces from one another, the hollow body has an inner hollow body wall and an outer hollow body wall spaced apart from it, so that an intermediate space is enclosed. The space between the two walls is formed on the hollow body to the full extent.

In this way, cooling of the hollow body can be made possible by the space between the inner hollow body perwand and the outer wall of the hollow body is filled with a cooling liquid. The coolant absorbs the heat transferred to the walls. The cooling liquid is exchanged particularly advantageously and the absorbed heat is thus carried out.

Water or any other liquid with a high heat capacity is used as the liquid. In particular, water is used as the liquid because water is cheaply available. The liquid is passed through the space for effective cooling. In addition, the flow direction and the flow rate can be predetermined by the installation of walls in the intermediate space and a resulting channel environment. The smaller the channel cross section, the higher the flow rate with a constant flow volume. For cooling, cold liquid enters the gap and warm liquid exits. The cooling can also not be active during the standby position of the hollow body, i.e. the liquid rests in the space. At the time of use, the cooling is then activated by passing the liquid through it. Alternatively, the cooling can be continuously active to ensure the function and rapid use.

It is expedient that the hollow body is mounted on rollers and / or rails so that the hollow body can be moved in a defined manner and damage to the vacuum chamber or the vapor deposition is reliably prevented during the movement. The guide is designed to be vacuum-compatible and thermally stable under the operating conditions. To move the hollow body, it is particularly expedient that the substrate protection device comprises at least one drive. The drive is preferably arranged outside the vacuum chamber and in this case acts on the hollow body via one or more transmission elements.

Ropes, tapes, belts, chains, toothed belts or the like are provided as transmission means. Doing so the direction of action of the force changed over the pulleys. Alternatively, the driving force is transmitted to the hollow body, for example by means of a telescopic device, by means of a device with a rack guide or the like. The transmission means and possibly the deflections are designed to be vacuum-compatible and thermally stable under the operating conditions.

The invention will be explained in more detail below on the basis of an exemplary embodiment. Show in the accompanying drawings

1 is a schematic representation of a vertical cross section through a coating device according to the invention with a substrate protection device,

Fig. 2 shows the coating device according to Fig. 1 with the substrate protection device in the operating position and

Fig. 3 is a schematic representation of a vertical cross section through a hollow body.

To the subject:

1 shows a coating device 1 according to the invention with a vacuum chamber 2 and an evaporation channel 3 arranged therein. The evaporation channel 3 has a height of approximately 4 meters and is arranged at the middle height of the approximately 10 meter high vacuum chamber 2. The vapor deposition channel 3 has the shape of an upright, elongated, hollow cuboid and is open at the base at the upper and lower ends. The outside of the vaporization duct 3 is provided in its entirety with a heating device 4, which is designed as an electrical resistance heater for radiant heating.

At the middle of the vacuum chamber 2 or the vaporization channel 3 is on two opposite sides, on both sides of the

Substrate, a nozzle 5 mounted essentially horizontally in the operating position, which with the respective narrow ends open into the vaporization duct 3. The other end of the nozzles 5 is connected to an evaporation device which serves to evaporate the coating material.

A belt-shaped substrate 6 is transported through the vacuum chamber 2 and through the vapor deposition channel 3. The substrate 6 is aligned in such a way that the surfaces are oriented transversely to the nozzle, the nozzle being directed in each case to the center of the surface of the substrate. The substrate can already be coated in a previous coating run.

The hollow body according to the invention is also located in the vacuum chamber 2 as a substrate protection device. This consists of two linearly movable units. Each unit comprises a hollow cuboid 7, which is open on the sides of the base areas for the passage of the substrate strip 6. The dimensions of the base area of a hollow cuboid 7 are smaller than the dimensions of the base area of the vapor deposition channel 3, and the height of a hollow cuboid 7 slightly exceeds half the height of the vapor deposition channel 3. Furthermore, the hollow cuboids 7 are directed towards one another, are mounted so as to be movable in parallel around the substrate belt 6 and in the direction of transport of the substrate belt 6.

In the standby position, a hollow cuboid 7 is held above and below the vaporization channel 3 (FIG. 1). In the operational position, i.e. H. after the two hollow cuboids have been introduced into the vapor deposition channel, the two hollow cuboids 7 abut one another with their opposite end faces at the level of the nozzles 5. In the contact plane of the two hollow cuboids 7, they lie in a vapor-tight manner on one another, so that the vapor deposition channel 3 is divided into an internal vapor deposition channel 11 and an external vapor deposition channel 12 (FIG. 2).

The cooling water supply to the hollow cuboid 7 takes place, for example, via meandering hose connections, not shown, which adapt to the differences in distance of the hollow cuboid 7 by opening their bending radius. Fig. 3 shows a hollow cuboid in cross section. The hollow cuboid 7 forms an intermediate space 10 between an outer hollow body wall 8 and an inner hollow body wall 9, which serves as a channel system. Water as cooling liquid 13 is passed through the channel system at a defined flow rate.

Each hollow cuboid 7 is guided on guide rails, not shown. For suspension, the hollow cuboid 7 has a cross strut 14 on the base side opposite the other hollow cuboid. Due to the length of the hollow cuboid, which is greater than half the length of the vaporization channel by at least one cross section of the cross strut, the cross struts of the suspension project out of the vaporization channel 3.

Outside the vacuum chamber 2, a drive, also not shown, is mounted with a shaft reaching into the vacuum chamber 2. The drive shafts are connected to the two hollow blocks 7 by means of traction means guided over deflection rollers.

About the procedure:

The coating method is a continuous thermal vacuum coating of the band-shaped substrate by evaporating solid coating material and vapor deposition of the vaporous coating material on the continuously transported substrate in the evaporation channel 3.

For this purpose, the solid coating material is heated in a vacuum and transported through the nozzle 5 on both sides of the substrate into the heated and evacuated evaporation channel 3. By means of a vapor-tight valve provided on the evaporator device, the inflow of vaporous coating material can be regulated and also interrupted.

The band-shaped substrate 6 made of steel is transported in the evaporation channel 3, the transport speed varying. iert and in the embodiment is between 30 meters per minute and 200 meters per minute.

The substrate transport is monitored with sensors via a computer-aided control unit. As soon as a disturbance occurs in the substrate transport and the substrate 6 does not emerge from the hot evaporation channel 3 or does not emerge quickly enough, a disturbance is registered.

In this case, the two drive outside, i.e. above and below the evaporation channel 3 in the vacuum chamber 4, aged hollow cuboid 7 as a thermal protective curtain and into the evaporation channel 3. In the contact plane, the two hollow guaders 7 lie so close to one another that no vaporous coating material penetrates into the vapor deposition inner chamber. During the coating process, the intermediate space 10 is filled with cooling water 11, which is passed through the intermediate space 10.

A control unit also prevents further loading of the vapor deposition channel 3 with pressing vapor coating material. The vaporous coating material located in the vaporization channel 3 and in the transport lines present between evaporation and vaporization means separates on the cooled, outer hollow body wall 8 and on the cooled, inner hollow body wall 9. At least the vapor deposition inner chamber is then essentially free of condensate of the coating material.

In the event of a fault, the heating of the steaming duct continues. Thus, the vaporous coating material is deposited essentially completely on the inner and outer hollow body walls 8, 9 of the hollow cuboid 7. Process and device for thermal vacuum coating

LIST OF REFERENCE NUMBERS

1 coating device 2 vacuum chamber 3 evaporation channel 4 heating device 5 nozzle 6 substrate 7 hollow body, hollow cuboid 8 outer hollow body wall 9 inner hollow body wall 10 intermediate space 11 evaporation inner duct 12 outer evaporation duct 13 cooling liquid 14 cross strut

Claims

Method and device for thermal vacuum coating

1. Process for the thermal vacuum coating of a continuously transported substrate by vaporization of solid and / or liquid coating materials and vapor deposition of the vaporous coating material on the substrate, the substrate moving in a heated vaporization channel of a vaporization device, characterized in that the vaporization channel (3) if the substrate falls below a minimum transport speed or if the substrate comes to a standstill by inserting at least one positionally variable hollow body (7) into an outer space (3) and an inner space such that the substrate is located in the inner space.

2. The method according to claim 1, characterized in that two hollow bodies (7) are inserted in a mutually directed movement and the two mutually directed end faces of the two hollow bodies (7) lie against one another in the inserted state.

3. The method according to any one of claims 1 or 2, characterized in that the hollow body (7) in a vacuum chamber (2) surrounding the evaporation channel (3) moves.

4. The method according to any one of claims 1 to 3, characterized in that the hollow body (7) is inserted parallel to the transport direction of the substrate (6).

5. experience according to one of claims 1 to 4, characterized in that the hollow body (7) is cooled.

6. The method according to any one of claims 1 to 5, characterized in that the loading of the vapor deposition channel (3) with vaporous coating material is prevented when the substrate does not reach a minimum transport speed or when the substrate is at a standstill.

7. Coating device, in particular for thermal vacuum coating of continuously transported substrate, consisting of an evaporation device, comprising a vacuum chamber and an evaporation channel (3) arranged in the vacuum chamber and enclosing the substrate, and an evaporation device connected to the evaporation channel, characterized in that when the temperature falls below a minimum transport speed of the substrate (6) or, when it is at a standstill, at least one hollow body (7) which can be inserted into the vapor deposition channel (3) surrounds the substrate (6).

8. Coating device according to claim 7, characterized in that the hollow body (7) is a prismatic or cylindrical hollow body.

9. Coating device according to one of claims 7 or 8, characterized in that the hollow body (7) is arranged with continuous substrate transport at least the minimum speed in a standby position outside the evaporation channel (3) and inside the vacuum chamber.

10. Coating device according to one of claims 7 to 9, characterized in that the hollow body (7) when falling below a minimum transport speed of the substrate (6) or when it is at a standstill in an application position essentially in the vapor deposition channel (3) is arranged.

11. Coating device according to one of claims 7 to 10, characterized in that two hollow bodies (7) are arranged in an insert position essentially in the vaporization channel (3), the two hollow bodies (7) lying against one another with their opposite end faces.

12. Coating device according to one of claims 7 to 11, characterized in that the hollow body (7) consists of high-temperature steel or a high-temperature alloy.

13. Coating device according to one of claims 7 to 12, characterized in that the hollow body (7) has an inner hollow body wall (9) and an outer hollow body wall (8) spaced apart therefrom, which enclose an intermediate space.

14. Coating device according to one of claims 7 to 13, characterized in that the hollow body (7) is mounted on rollers and / or rails.

15. Coating device according to one of claims 7 to 14, characterized in that the hollow body (7) can be moved by means of a drive.

16. Coating device according to claim 15, characterized in that the hollow body (7) is connected to the drive via transmission means.