DE102008034960A1 - Method for coating a substrate with a transparent metal-oxide layer by magnetron sputtering, comprises moving the substrate in a coating chamber on tube cathode, whose mantle surface comprises sputterable target materials - Google Patents

Abstract

The method comprises moving a substrate in a coating chamber on tube cathode, whose mantle surface comprises sputterable target materials, which are arranged in the substrate transport direction to each other, extend itself over the substrate width and comprises magnet system extending in its interior area over the length of the tube cathode. The metal oxide layer is separated under presence of oxygen in the coating atmosphere on the substrate. The substrate is coated in an area, which is limited by screens, which cover the edge of the substrate in the substrate transport direction. The method comprises moving a substrate in a coating chamber on tube cathode, whose mantle surface comprises sputterable target materials, which are arranged in the substrate transport direction to each other, extend itself over the substrate width and comprises magnet system extending in its interior area over the length of the tube cathode. The metal oxide layer is separated under presence of oxygen in the coating atmosphere on the substrate. The substrate is coated in an area, which is limited by screens, which cover the edge of the substrate in the substrate transport direction in which the screens are arranged over the substrate so that an unhindered substrate carrier is guaranteed. The magnet systems are rotated during the coating to a longitudinal axis of the tube cathode in the direction of the other tube cathode in such a way that the normal of the respective middle magnet poles has an angle of 0-45[deg] measured to the normal of the substrate. The magnet systems are rotated to 0[deg] . The screens cover the chamber wall of the coating chamber in the area beneath the tube cathode in the substrate transport direction. The coating is carried out with two tube cathodes that have a distance D and H to the substrate plain in which the substrate is movable through the coating chamber, where the ratio of the H/D is 0.4-1.2. A conductive transparent layer is deposited. An independent claim is included for a coating chamber for coating a substrate with a transparent metal-oxide layer.

Description

The The invention relates to a method for coating a substrate with a transparent metal oxide layer by means of magnetron sputtering, by placing the substrate in a coating chamber on tube cathodes is moved past, the lateral surfaces of which sputterbare Have target material and which in the substrate transport direction are arranged side by side. The tube cathodes extend over the substrate width and each have in their interior over the length of the tube cathode extending magnetic system. The metal oxide layer is in the presence of oxygen in the Coating atmosphere deposited on the substrate.

The The invention also relates to a coating chamber for a coating system for carrying out the method.

At the Magnetron sputtering is in the process gas between the to be coated Substrate and a tube cathode ignited a plasma whose positive charge carriers by the so-called sputtering effect (dusting, d. H. zone bombardment induced strike out of atoms from the solid surface) the upper layers ablate a target surface. It can Metals are sputtered in the presence of oxygen and as an oxide are deposited on the substrate. It is also possible Use oxides or other metal compounds as the target material and to sputter. Dissociation often occurs in the latter d. H. Release of oxygen during the sputtering process. But it is also possible that the metal oxides or metal compounds sputtered without dissociation and deposited on the substrate become. In the presence of oxygen in the process gas that reacts ablated sputtering material with the oxygen as the reactive gas and suggests itself as oxide on one opposite arranged substrate down. The chemical reaction to stoichiometric Bonding layers on the substrate will pass through with the sputtering process linked plasma discharge and the resulting energetic excitation of the reactants, also known as species, strengthened.

A Provision of the reactive gas or its supplement at Losses due to vacuum generation or when setting a defined gas fraction takes place either by a targeted supply into the coating chamber by means of a gas inlet system.

to Support for plasma formation as well as acceleration The ions on the target surface are on the plasma opposite side of the target a magnet system with juxtaposed Magnets of locally changing polarity arranged. As is known, exists such, used for magnetic sputtering magnetic system from a central magnetic pole the second, opposite Magnetic pole surrounds annular. Because of this as a ring forming, tunnel-shaped magnetic field is the target material over the gap between two magnetic poles, where the magnetic field lines run parallel to the target surface, worn to a special extent, so that in this area forming an annular sputter trench. This one will too referred to as Racetrack. The local course of the magnetic guided, self-contained plasma symbiosis correlated with the erosion of the target material.

To the Magnetetrun sputtering, in addition to planar cathodes, also becomes tube cathodes used. The latter are in particular for the coating of different large-area substrates known and are hereby often used as a double cathode. Tube cathodes are cylindrical and rotatable about its longitudinal axis and are characterized by a high rate of utilization of the on the lateral surface of the tube cathodes arranged target material and a long target life. The lateral surfaces of the tube cathodes consist of sputterable Target material, wherein the target material either as a tubular Target may be formed so that the cylinder of the tube cathode completely from the material to be sputtered, z. B. off Aluminum or titanium, or the tube cathodes are made a carrier tube which coats with the material to be sputtered is. Independent of the respective execution is usually spoken of a pipe target.

in the Interior of both tube cathodes is arranged in each case a magnet system, which extends over the entire length of the tubular cathode extends and viewed in cross-section of at least three. nebeneinander arranged magnet consists. As a result of this magnet arrangement forms in each case an annular racetrack on the tube target out, and extends parallel to the longitudinal axis of the tube target over its entire length. The tube cathode is related to the Magnet system rotatably arranged so that in the coating operation The tube cathode can rotate while the magnet system is steady remains aligned in the coating chamber. By a uniform Rotation of the tubular cathodes in a stationary magnetic field passes through the entire cylindrical target surface the racetrack area. and it becomes a uniform erosion of the target material achieved.

In the German utility model DE 20 2005 015 067 U1 a cathode assembly and a coating chamber is described in which the cathode assembly for coating planar substrates is used in a continuous process. There are a single enlarged tube cathode or two tube cathodes arranged side by side. In order to keep the coating material from components and walls of the coating chamber spreading in the entire space of the coating chamber and in particular between the tube cathodes and the substrate, diaphragms are arranged next to the tube cathodes and perpendicular to the transport direction of the substrate, which also cover the edge regions of the substrate.

By means of tubular cathodes, a wide variety of materials can be sputtered, both electrically conductive and dielectric. The target consists, for. B. of metals, alloys or oxide materials. In the WO 92/01081 two or more tube cathodes are used side by side with divergent target material to deposit a mixed layer by so-called cross-contamination. In this case, a portion of the sputtered target material of each tube cathode is directed to the other tube cathode, so that sputtered from both tube cathodes, a mixture of both target materials to deposit a layer which is composed evenly of the two target materials. The contamination of the respective other target is effected by a rotation of the magnet arrangement in each tube cathode in the direction of the other tube cathode.

By reactive magnetron sputtering of metallic targets or magnetron sutures of metal oxide targets are z. B. metal oxide layers, at Using suitable sputtering materials can be transparent, deposited. Such oxide layers are due to their optical Properties for a number of different applications used. Applications are z. B. transparent electrodes in flat screens, in thin film solar cells or optically selective components Layer systems. According to the application possibilities come various substrates into consideration, for. As glass, metal, silicon or flexible plastic films. It is known, transparent conductive To produce layers of different metal oxide layers, the in addition, by suitable doping with a material the third main group of the Periodic Table of the Elements, z. B. Aluminum or gallium the required conductivity can have. Such transparent conductive Layers are as TCO layer (Transparent Conducting Metal Oxide - TCO) known, for. B. layers of indium oxide, tin oxide or indium-tin oxide (ITO), with layers of zinc oxide gaining in importance as they cheaper to manufacture, non-toxic, easy to dope and are durable under hydrogen-containing atmosphere. The Coating takes place in vacuum coating systems, depending on one or more of the layers or layer systems to be applied Have coating chambers.

A Essential requirement for a transparent metal oxide layer is their transmission, which is directly linked to the sheet resistivity is, and the homogeneity of the optical properties. In The known method has the problem that the transmission the deposited layer at least in sections through a sub-layer is diminished, which is not or substoichiometric Oxidized target material above or below the actual, Metal oxide layer is deposited. This parasitic Intermediate layer has a due to the different layer composition higher absorption and thus a much lower degree of transmission on, the optical properties of the metal oxide layer in not negligibly changes.

It Therefore, an object of the present invention is a method for magnetron sputtering by means of tubular cathodes and a device for implementation of the method with which it is possible to specify the Transmission of continuous metal oxide layers increase by training parasitic, Light absorbing sublayers is avoided.

With The described methods and devices make it possible everywhere there in the coating chamber where atomized, vaporous target material over abutting the substrate, plasma of the desired density and to provide homogeneity. Method and device allow it, inevitable scattering steam, either by means of shutters suppress or sufficient by plasma action Activate so that only homogeneous, stoichiometric and thus depositing highly transparent metal oxide layers on the substrate become. The scattered vapor is the atomized target material referred to, either in the edge region of the spatial Distribution is located within the coating chamber or in intermediate spaces penetrates, which are opposed by apertures or chamber fittings the tube cathodes are shadowed, such as between diaphragms and Substrate.

The avoidance of the effects of scattered steam on the transmission of the metal oxide layer is achieved, on the one hand, by arranging diaphragms in the edge region of the substrate, which are usually mounted on the chamber wall, so closely above the substrate that no or only a negligible proportion of scattering vapor can get to the substrate. Supporting this effect, at the same time, the magnet system within the tube cathodes is rotated in such a way that the main propagation direction of the target material and plasma is directed less towards the edge regions of the substrate and towards the center. Consequently, only in the area coated on the substrate, which lies between the panels.

A sufficient orientation of the particle streams on the substrate, so that the homogenizing effect on the substrate or at least in its immediate vicinity and not on the adjacent tube cathode depends essentially on the distance of the Tube cathodes to each other and to the substrate from. That's how it turned out that in the transmission of the deposited metal oxide layer the best results are achieved when the ratio between the distance tube cathodes - substrate to the distance tube cathode - tube cathode is in a range of 0.4 to 1.2.

There in the course of substrate transport, each of the perpendicular to the Substrattransportrichtung lying substrate strip moves under both tube cathodes therethrough is, are the substrate stripwise covering Apertures arranged only at the entrance and exit of the coating chamber. In this way it is avoided that scattered steam under the input side panel passes and there as an absorbing layer on the substrate precipitates before by the further transport of the substrate above the metal oxide layer is deposited and under the output side diaphragm is another parasitic forms absorbent layer.

There in moving substrates, the tube cathodes with their magnetic systems to obtain a homogeneous over the substrate width layer over the extend entire substrate width are at the lateral edge of the substrates no screens to shield the areas with deposition rates below a predefined size required.

dazzle to protect the chamber wall and the internals of the coating chamber but may be necessary, but then with such a Distance to the substrate to arrange that the access of plasma and Target material in this edge area is not hindered or relevant comparable to the input and output side apertures is prevented. In one embodiment, the panels are used to shield the chamber components combined with the shields to shield the substrate edges by one leg of the panels is so long and so mounted is that he has the chamber wall in the most by target material covered area under the tube cathodes covered.

Of the Access of target material in gaps depends at the high vacuum conditions required for sputtering mainly from the material properties. So will z. For example, zinc is strongly scattered and diffused in the argon process gas As a result, reinforced as scattering steam throughout Coating chamber off. In addition occurs that z. As zinc a small Sticking coefficient (sticking coefficient) has, so the distribution the scattering vapor by adhesion to components of the coating chamber is reduced only conditionally. So also have more atomic effects Influence on the spread of scattered steam. Consequently, the distance is the covering the substrate on the used Match target materials. Here it proves to be an advantage when the aperture distance to the substrate and thus to the plane, in which the substrate is moved through the coating chamber, is adjustable.

The Rotation of the magnet systems should be done to the extent that the main propagation direction of target material and plasma always runs to the substrate and over the free substrate surface the distribution characteristics of atomized target material and plasma density the required homogeneity is present. Dependent on from the distance between the tube cathodes to each other and their distance from the substrate This angle can range up to about 45 ° and so that they are well below 90 °, because of the spatially spreading target material and plasma cloud the Accuracy of the angle adjustment to a few degrees sufficient is.

Not inhomogeneities to be avoided at the beginning and at the end of the Chamber lead as described above but not to a Modification of the coating composition but only reduced Layer thicknesses caused by the transport of the substrate through the chamber and thus be compensated perpendicular to these thickness variations. These Adjustment of plasma homogeneity is by such Rotation of the magnet systems in the direction of each other, d. H. towards the center of the chamber possible, with that of the chamber center From the outside racetrack section at least is rotated to the normal, which of the longitudinal axis of the tube cathodes falls on the substrate plane. At the Cross section considered three-pole magnetic systems proves a turn of 20 ° as favorable. As normal is generally called the straight line, in a given Point of a plane curve (curve normal) or a surface (Surface normal) perpendicular to the tangent or to the tangent plane in the point.

The effect described above is also achieved in an alternative embodiment of the method according to the invention in that the tube cathode facing substrate surface not only across the width but also over the entire length, viewed in the substrate transport direction, free of shading panels, so that the entire, in the coating chamber the tube cathode facing substrate surface is coated. This produces comparable conditions here, as described above for the closely above the substrate arranged aperture. The entire surface of the substrate directed or scattered with target material is to a certain extent visible from the plasma sources, ie also the racetracks.

So far Apertures to protect the chamber wall and chamber fittings necessary Once again, they should be designed and assembled in this way be that they do not shade the substrate. This is done in one Design of the coating chamber, in the comma-shaped Apertures are used, which are open to the chamber wall, so that these do not form shadowing projections and the substrate can be coated in the entire area can. Depending on the shape of the chamber wall, installations or possible openings in the wall, the comma-shaped panels can directly be mounted on the chamber wall or at a distance therefrom. For example, apertures shaped in this way allow the aperture to be apertured the chamber wall can protrude.

Also in this second, alternative solution to the task is a rotation of the magnet systems towards each other possible, but not required because of plasma and target material spread equally through the chamber wall of the coating chamber is limited. Consequently, here is also a vertical orientation the magnet systems possible, d. H. an angle of 0 ° between the normal of the center magnetic pole and the normal of the substrate opposite to the longitudinal axis of the tube cathodes lying point. In this position are the parallel sections of the racetrack of a tube cathode in a plane parallel to the Substrate level is. A turn, however, can z. B. for targeted Adjustment of the area distribution of the deposition rates be used. The preferred angle of rotation is on the obi gene References.

The Invention will be described below with reference to an embodiment be explained in more detail. In the associated Drawing shows

1 a coating chamber with a pair of tubular cathodes and

2 an embodiment of the edge region of a substrate releasing aperture.

In 1 a coating chamber of a sputter coating system is shown. Within the coating chamber are two tube cathodes 1 arranged as cylindrical, around its longitudinal axis 3 rotatable carrier tubes 2 are formed. On the lateral surface of the carrier tubes 2 is the target material 4 layered applied, z. B. a material mainly containing zinc. In the exemplary embodiment, both tube cathodes comprise 1 the same target material 4 , Alternatively, there are also different target materials 4 usable, for. B. to form a layer stack, each consisting of a sub-layer of a target material 4 with an intermediate layer of a mixture of both materials.

The tube cathodes 1 extend transversely to the substrate transport direction 6 in which a substrate 5 by means of a suitable transport device 7 through the coating chamber and continuing through the entire coating system. In their longitudinal extent perpendicular to the plane of the drawing correspond to the tube cathodes 1 approximately the width of the substrate or extend beyond.

Inside the tube cathodes 1 are magnetic systems 9 are each arranged a two-pole permanent magnet, both of which have a shape with three poles in cross-section due to the outer, annularly around the inner magnetic pole. The polarity is in the embodiment for both magnet systems 9 displayed as north-south-north, but may also be south-north-south. Both magnet systems 9 should have the same polarity. The magnet systems 9 are relative to the tube cathodes 1 Rotatable about the longitudinal axis, so that they are in the rotation of the tube cathodes 1 remain stationary relative to the surrounding coating chamber.

Both magnet systems 9 are rotated with opposite direction of rotation towards the center of the chamber such that the normal 12 of the respective middle magnetic pole 10 has an equal angle φ of about 20 ° measured to the normal 14 of the substrate 5 that in the representation of the longitudinal axis 3 the tube cathode 1 on the substrate 5 and thus on the substrate level 16 falls.

Around the intersection of the two normals 12 always, ie even at the maximum angle of rotation of 45 °, below the lower edge of both tube cathodes 1 set, the tube cathodes to each other and to the substrate plane are spaced such that the ratio H / D between distance H of the longitudinal axes of the tube cathodes 1 to the substrate level 16 and the distance D of the longitudinal axes 3 the tube cathodes 1 always in the range between 0.4 and 1.2. Often one of the distances H, D is conditioned by the plant.

By using two tube cathodes 1 On the one hand, the operating time of the system can be increased. On the other hand, by the oppositely directed angle of rotation φ of the two magnet systems 9 improves the plasma density distribution and the distribution of the sputtered target material. If in one embodiment of the invention more than two tube cathodes 1 to be placed in a coating chamber, become pairs of tube cathodes 1 used so that in each pair the magnet systems 9 equally rotated against each other can be arranged.

The substrate 5 becomes in the substrate plane 16 lying through the coating chamber and thereby to the tube cathodes 1 transported by. On the input side and output side, the chamber wall 20 the coating chamber one passage each 22 for extending and retracting the sub strate 5 on. Above both passages 22 is on the chamber wall 20 each an L-shaped aperture 24 assembled. The longer of the two legs of the panel 24 is on the chamber wall 20 attached and has such a length that it is the chamber wall 20 below both tube cathodes 1 covered. The shorter leg of the panel 24 protrudes parallel to the surface of the substrate 5 in the coating chamber and in the embodiment has a distance A to the substrate 5 of 20 mm.

2 shows a comma-shaped embodiment of the aperture 24 consisting of two approximately equal length and with an obtuse angle to each other inclined legs. The upper of the two legs is in turn on the chamber wall 20 the coating chamber mounted so that it partially passes the passage 22 covered. Due to the opening of the comma form to the chamber wall 20 towards covers the aperture 24 the substrate 5 although when viewed perpendicularly to the substrate 5 , However, based on the vapor and plasma spread from the tube cathodes 1 from there is no shading of the substrate 5 , In the exemplary embodiment, the aperture 24 a distance A of 15 mm to the substrate 5 on.

Due to the planar substrates shown in the embodiment 5 Such a distance is sufficient to transport the substrates 5 through the chamber without contact between substrate 5 and aperture 24 to ensure. Become curved substrates 5 coated or their requirements for the flatness less, the distance A of the aperture is adjusted accordingly, so that just an unimpeded substrate transport is possible.

During the coating, a plasma is ignited where the magnetic field lines are parallel to the target surface, thus centered between two magnetic poles 10 every magnet system 9 , In this area, the racetracks form 26 in which the target material 4 from the outer surface of the two rotating tube cathodes 1 is sputtered. As a result of the rotation, however, no trenches are formed. Rather, the target material 4 evenly from the entire surface of the tube cathodes 1 ablated. The sputtered target material spreads towards the substrate 5 reacts with the oxygen introduced into the coating chamber or released by dissociation from the oxidic target material and is expressed as zinc oxide on the substrate 5 deposited.

1

tube cathode

2

support tube

3

longitudinal axis

4

target material

5

substratum

6

Substrate transport direction

7

transport device

9

magnet system

10

magnetic pole

12

normal of the middle magnetic pole

14

normal of the substrate, normal of the substrate plane

16

substrate plane

20

chamber wall

22

passage

24

cover

26

Racetrack

φ

angle

A

distance Aperture - Substrate

D

distance the longitudinal axes of the tube cathodes to each other

H

distance the longitudinal axes of the tube cathodes to the substrate level

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 202005015067 U1 [0008]
• WO 92/01081 [0009]

Claims (16)

Method for coating a substrate ( 5 ) with a transparent metal oxide layer by means of magnetron sputtering by the substrate ( 5 ) in a coating chamber on tube cathodes ( 1 ) is moved past whose outer surfaces the sputterable target material ( 4 ) and which in the substrate transport direction ( 6 ) are arranged side by side, extending over the substrate width and in each case in their interior over the length of the tubular cathode ( 1 ) extending magnet system ( 9 ), and the metal oxide layer preferably in the presence of oxygen in the coating atmosphere on the substrate ( 5 ), characterized in that the substrate ( 5 ) is coated in a region which is blocked by diaphragms ( 24 ), which corresponds to the substrate transport direction ( 6 ) considers the front and rear edges of the substrate ( 5 ) by covering the panels ( 24 ) so close to the substrate ( 5 ) are arranged so that an unhindered substrate transport is just still guaranteed, and that during the coating, the magnetic systems ( 9 ) about the longitudinal axis ( 3 ) of the tube cathode ( 1 ) in the direction of the other tube cathode ( 1 ) are rotated such that the normal ( 12 ) of the respective middle magnetic pole ( 10 ) has an angle in the range between 0 ° and 45 °, measured to the normal ( 14 ) of the substrate ( 5 ). Method according to claim 1, characterized in that the magnet systems ( 9 ) are rotated such that said angle is 20 °. Method according to one of the preceding claims, characterized in that the diaphragms ( 24 ) in the substrate transport direction ( 6 ) views the front and rear chamber walls ( 20 ) of the coating chamber in the region below the tube cathodes ( 1 ) cover. Method for coating a substrate ( 5 ) with a transparent metal oxide layer by means of magnetron sputtering by the substrate ( 5 ) in a coating chamber on tube cathodes ( 1 ) is moved past whose outer surfaces the sputterable target material ( 4 ) and which in the substrate transport direction ( 6 ) are arranged side by side, extending over the substrate width and in each case in their interior over the length of the tubular cathode ( 1 ) extending magnet system ( 9 ), and the metal oxide layer preferably in the presence of oxygen in the coating atmosphere on the substrate ( 5 ) is deposited, characterized in that on the entire, located in the coating chamber and the tube cathodes facing surface of the substrate ( 5 ) the transparent metal oxide layer is deposited and that during the coating the magnetic systems ( 9 ) about the longitudinal axis ( 3 ) of the tube cathode ( 1 ) in the direction of the other tube cathode ( 1 ) are rotated such that the normal ( 12 ) of the respective middle magnetic pole ( 10 ) has an angle in the range of 0 ° to 45 °, measured to the normal ( 14 ) of the substrate ( 5 ). Method according to claim 4, characterized in that the magnet systems ( 9 ) are rotated such that said angle is 0 °. Method according to one of the preceding claims, characterized in that the coating with two tube cathodes ( 1 ) takes place which a distance D to each other and a distance H to the substrate plane ( 16 ), in which the substrate ( 5 ) is moved through the coating chamber, wherein the ratio H / D has a value in the range of 0.4 to 1.2. Method according to one of the preceding claims, characterized in that a conductive transparent Layer is deposited. Coating chamber for coating moving substrates ( 5 ) by means of magnetron sputtering in the substrate transport direction ( 6 ) arranged side by side, over the substrate width extending tube cathodes ( 1 ) whose lateral surfaces the sputterable target material ( 4 ) and which in their interior each have a magnet system extending over the length thereof ( 9 ) and with a transport device ( 7 ) for transporting the substrates ( 1 ), characterized in that in the substrate transport direction ( 6 ) views the front and rear edge regions of the coating chamber above the substrate plane ( 16 ), in which the substrate ( 5 ) is moved through the coating chamber, aperture ( 24 ) so close above the substrate plane ( 16 ) are arranged so that an unhindered substrate transport is barely guaranteed, and that the magnet systems ( 9 ) about the longitudinal axis ( 3 ) of the tube cathode ( 1 ) in the direction of the other tube cathode ( 1 ) are rotated such that the normal ( 12 ) of the respective middle magnetic pole ( 10 ) has an angle in the range between 0 ° and 45 °, measured to the normal ( 14 ) the substrate level ( 16 ). Coating chamber according to claim 8, characterized in that that said angle is 20 °. Coating chamber according to one of claims 8 or 9, characterized in that the diaphragms ( 24 ) have an L-shape, one leg of which on the chamber wall ( 20 ) and whose second leg is parallel to the substrate plane ( 16 ) protrudes into the coating chamber. Coating chamber according to one of the An claims 7 to 10, characterized in that the distance of the aperture ( 24 ) above the substrate level ( 16 ) is adjustable. Coating chamber for coating moving substrates ( 5 ) by means of magnetron sputtering in the substrate transport direction ( 6 ) arranged side by side, over the substrate width extending tube cathodes ( 1 ) whose lateral surfaces the sputterable target material ( 4 ) and which in their interior each have a magnet system extending over the length thereof ( 9 ) and with a transport device ( 7 ) for transporting the substrates ( 5 ), characterized in that arranged in the coating chamber internals are arranged such that an unimpeded plasma propagation of the tube cathodes ( 1 ) located in the coating chamber, the tube cathodes ( 1 ) facing substrate surface is ensured. Coating chamber according to claim 12, characterized in that on the chamber wall ( 20 ) of the coating chamber above the substrate plane ( 16 ) Aperture ( 24 ) above the substrate level ( 16 ) are arranged so that an unhindered substrate transport is ensured, and that the aperture ( 24 ) have a comma shape and directly with an upper portion on the chamber wall ( 20 ) or at a distance therefrom, while the lower, angled portion to the chamber wall ( 20 ). Coating chamber according to one of claims 8 to 13, characterized in that two tube cathodes ( 1 ) are arranged side by side, the distance D to each other and a distance H to the substrate plane ( 16 ), wherein the ratio H / D has a value in the range of 0.4 to 1.2. Coating chamber according to one of claims 7 to 14, characterized in that the target material ( 4 ) Tin, zinc, cadmium, gallium, indium, compounds thereof or mixtures containing these materials. Coating plant for coating substrates ( 5 ) in a continuous process by means of reactive magnetron sputtering, characterized in that the coating system comprises at least one coating chamber according to one of claims 7 to 15.