WO2015172835A1

WO2015172835A1 - Apparatus and method for coating a substrate by rotary target assemblies in two coating regions

Info

Publication number: WO2015172835A1
Application number: PCT/EP2014/059975
Authority: WO
Inventors: Marcus Bender; Fabio Pieralisi; Evelyn Scheer; Daniel Severin; Harald Gärtner; Ralph Lindenberg
Original assignee: Applied Materials, Inc.
Priority date: 2014-05-15
Filing date: 2014-05-15
Publication date: 2015-11-19
Also published as: TW201608044A; CN206654950U; KR20170000267U

Abstract

According to an embodiment, a sputter deposition apparatus for coating a substrate is provided. The sputter deposition apparatus has two or more coating regions for coating the substrate. The sputter deposition apparatus includes a first substrate guiding system for guiding the substrate in a first coating region, wherein the first substrate guiding system defines a first substrate transport direction. The sputter deposition apparatus further includes a second substrate guiding system for guiding the substrate in a second coating region, the second substrate guiding system defining a second substrate transport direction. The second substrate transport direction is the same direction as the first substrate transport direction or is different from the first substrate transport direction. The sputter deposition apparatus further includes a first cathode assembly adapted for generating one or more plasma regions in the first coating region, a second cathode assembly adapted for generating one or more plasma regions in the first coating region, a third cathode assembly adapted for generating one or more plasma regions in the second coating region, and a fourth cathode assembly adapted for generating one or more plasma regions in the second coating region. The first cathode assembly includes: a first rotary target assembly adapted for rotating a target material around a first rotation axis; and a first magnet assembly fixedly positioned in the first rotary target assembly, the first magnet assembly having a first principal plane forming a first angle with a first reference plane which contains the first rotation axis and is perpendicular to the first substrate transport direction. The second cathode assembly includes: a second rotary target assembly adapted for rotating a target material around a second rotation axis; and a second magnet assembly fixedly positioned in the second rotary target assembly, the second magnet assembly having a second principal plane, the second principal plane being parallel to the first principal plane. The third cathode assembly includes: a third rotary target assembly adapted for rotating a target material around a third rotation axis; and a third magnet assembly fixedly positioned in the third rotary target assembly, the third magnet assembly having a third principal plane forming a second angle with a second reference plane which contains the third rotation axis and is perpendicular to the second substrate transport direction, wherein the second angle is different from the first angle. The fourth cathode assembly includes: a fourth rotary target assembly adapted for rotating a target material around a fourth rotation axis; and a fourth magnet assembly fixedly positioned in the fourth rotary target assembly, the fourth magnet assembly having a fourth principal plane, the fourth principal plane being parallel to the third principal plane.

Description

APPARATUS AND METHOD FOR COATING A SUBSTRATE BY ROTARY TARGET ASSEMBLIES IN TWO COATING REGIONS

FIELD

[0001] Embodiments relate to layer deposition by sputtering from a target. Some embodiments particularly relate to sputtering layers on large area substrates. Some embodiments particularly relate to static deposition processes. Embodiments relate specifically to an apparatus and a method for coating a substrate in a first coating region and in a separate second coating region, in particular for sputtering target material on the substrate.

BACKGROUND

[0002] In many applications, it is necessary to deposit thin layers on a substrate, e.g. on a glass substrate. The substrates are often coated in different chambers of a coating apparatus. The substrates may be coated in a vacuum, using a vapor deposition technique.

[0003] Several methods are known for depositing a material on a substrate. For instance, substrates may be coated by a physical vapor deposition (PVD) process, a chemical vapor deposition (CVD) process or a plasma enhanced chemical vapor deposition (PECVD) process etc. The process is performed in a process apparatus or process chamber where the substrate to be coated is located. A deposition material is provided in the apparatus. A plurality of materials, but also oxides, nitrides or carbides thereof, may be used for deposition on a substrate. Coated materials may be used in several applications and in several technical fields. For instance, substrates for displays are often coated by a physical vapor deposition (PVD) process. Further applications include insulating panels, organic light emitting diode (OLED) panels, substrates with thin film transistors (TFT), color filters or the like.

[0004] For a PVD process, the deposition material can be present in the solid phase in a target. By bombarding the target with energetic particles, atoms of the target material, i.e. the material to be deposited, are ejected from the target. The atoms of the target material are deposited on the substrate to be coated. In a PVD process, the sputter material, i.e. the material to be deposited on the substrate, may be arranged in different ways. For instance, the target may be made from the material to be deposited or may have a backing element on which the material to be deposited is fixed. The target including the material to be deposited is supported or fixed in a predefined position in a deposition chamber. In the case where a rotatable target is used, the target is connected to a rotating shaft or a connecting element connecting the shaft and the target. [0005] Sputtering can be conducted as magnetron sputtering, wherein a magnet assembly is utilized to confine the plasma for improved sputtering conditions. Thereby, the plasma confinement can also be utilized for adjusting the participle distribution of the material to be deposited on the substrate. The plasma distribution, the plasma characteristics and other deposition parameters need to be controlled in order to obtain a desired layer deposition on the substrate.

[0006] For example, a uniform layer with specific layer properties is desired. This is particularly important for large area deposition, e.g. for manufacturing displays on large area substrates. Further, uniformity and process stability can be particularly difficult to achieve for static deposition processes, wherein the substrate is not moved continuously through a deposition zone.

[0007] Accordingly, considering the increasing demands for the manufacturing of optoelectronic devices and other devices on a large scale, process uniformity and/or stability needs to be further improved.

SUMMARY

[0008] According to an embodiment, a sputter deposition apparatus for coating a substrate is provided. The sputter deposition apparatus has two or more coating regions for coating the substrate. The sputter deposition apparatus includes a first substrate guiding system for guiding the substrate in a first coating region, wherein the first substrate guiding system defines a first substrate transport direction. The sputter deposition apparatus further includes a second substrate guiding system for guiding the substrate in a second coating region, the second substrate guiding system defining a second substrate transport direction. The second substrate transport direction is the same direction as the first substrate transport direction or is different from the first substrate transport direction. The sputter deposition apparatus further includes a first cathode assembly adapted for generating one or more plasma regions in the first coating region, a second cathode assembly adapted for generating one or more plasma regions in the first coating region, a third cathode assembly adapted for generating one or more plasma regions in the second coating region, and a fourth cathode assembly adapted for generating one or more plasma regions in the second coating region. The first cathode assembly includes: a first rotary target assembly adapted for rotating a target material around a first rotation axis; and a first magnet assembly fixedly positioned in the first rotary target assembly, the first magnet assembly having a first principal plane forming a first angle with a first reference plane which contains the first rotation axis and is perpendicular to the first substrate transport direction. The second cathode assembly includes: a second rotary target assembly adapted for rotating a target material around a second rotation axis; and a second magnet assembly fixedly positioned in the second rotary target assembly, the second magnet assembly having a second principal plane, the second principal plane being parallel to the first principal plane. The third cathode assembly includes: a third rotary target assembly adapted for rotating a target material around a third rotation axis; and a third magnet assembly fixedly positioned in the third rotary target assembly, the third magnet assembly having a third principal plane forming a second angle with a second reference plane which contains the third rotation axis and is perpendicular to the second substrate transport direction, wherein the second angle is different from the first angle. The fourth cathode assembly includes: a fourth rotary target assembly adapted for rotating a target material around a fourth rotation axis; and a fourth magnet assembly fixedly positioned in the fourth rotary target assembly, the fourth magnet assembly having a fourth principal plane, the fourth principal plane being parallel to the third principal plane.

[0009] According to another embodiment, a method is provided for coating a substrate in a first coating region and in a separate second coating region. The method includes providing the substrate to the first coating region. The method further includes sputtering a surface of the substrate with a first target material. The first target material is sputtered onto the surface in the first coating region at a first sputtering angle relative to the substrate surface. The first sputtering angle is the only angle at which a target material is sputtered onto the substrate surface throughout the sputtering process in the first coating region. The method further includes providing the substrate to the second coating region. The method further includes sputtering the surface of the substrate with a second target material. The second target material is equal to the first target material or different from the first target material. The second target material is sputtered onto the surface in the second coating region at a second sputtering angle relative to the substrate surface. The first sputtering angle and the second sputtering angle are different, and the second sputtering angle is the only angle at which a target material is sputtered onto the substrate surface throughout the sputtering process in the second coating region.

[0010] Embodiments are also directed to methods for operating the disclosed system. These method or parts thereof may be performed manually or automated, e.g. controlled by a computer programmed by appropriate software, by any combination of the two or in any other manner.

[0011] Further advantages, features, aspects and details that can be combined with embodiments described herein are evident from the dependent claims, the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] A full and enabling disclosure to one of ordinary skill in the art is set forth more particularly in the remainder of the specification including reference to the accompanying drawings wherein:

Figs. 1 and 2 show a cross-sectional views of a sputter deposition apparatus according to embodiments described herein;

Figs. 3a and 3b illustrate a method of coating a substrate according to embodiments described herein at different instances in time;

Figs. 4a and 4b illustrate a method of coating a substrate according to embodiments described herein at different instances in time;

Figs. 5a-b illustrate a method of coating a substrate in a first coating region and in a second coating region according to embodiments described herein;

Fig. 6 shows a flow diagram of a method of coating a substrate in a first coating region and in a second coating region according to embodiments described herein.

DETAILED DESCRIPTION

[0013] Reference will now be made in detail to the various embodiments, one or more examples of which are illustrated in the figures. Within the following description of the drawings, the same reference numbers refer to same components. Generally, only the differences with respect to individual embodiments are described. Each example is provided by way of explanation and is not meant as a limitation. Further, features illustrated or described as part of one embodiment can be used on or in conjunction with other embodiments to yield yet a further embodiment. It is intended that the description includes such modifications and variations.

[0014] Embodiments described herein relate to apparatuses and methods for coating a substrate. In a coating process, a layer of target material is deposited on a substrate. In many cases, it is desired that a homogeneous layer of target material be deposited onto the substrate. The terms "coating process" and "deposition process" shall herein be used synonymously.

[0015] As used herein, the term "cathode assembly" should be understood as an assembly which is adapted for being used as a cathode in a coating process, such as a sputter deposition process. A cathode assembly may be adapted to be mounted in a coating chamber.

[0016] A cathode assembly may include a rotary target assembly which is rotatable around a rotation axis of the cathode assembly. The rotary target assembly may have a curved surface, for example a cylindrical surface. A target material, which may contain the material to be deposited onto a substrate during a coating process, may be mounted on the rotary target assembly.

[0017] A cathode assembly may include one magnet assembly. The magnet assembly may be arranged within a rotary target assembly of the cathode assembly. The position of the magnet assembly within the rotary target assembly affects the direction in which target material is sputtered away from the cathode assembly during a sputter deposition process. A magnet assembly may generate a magnetic field. The magnetic field causes one or more plasma regions to be formed near the magnetic field during a sputter deposition process.

[0018] A cathode assembly according to embodiments contains one single magnet assembly, i.e., precisely one magnet assembly and not more.

[0019] Fig. 1 shows a cross-sectional view of a sputter deposition apparatus 5 according to an embodiment. The sputter deposition apparatus shown in Fig. 1 includes four cylindrical cathode assemblies 10, 20, 30, and 40. The cathode assemblies are cylindrical rotary target assemblies, represented as circles, and extend into and/or out of the drawing plane. Also the magnet assemblies extend into and/or out of the drawing plane. The cathode assemblies 10 and 20 are adapted for sputtering target material onto a substrate (not shown), wherein the substrate is to be provided to a first coating region 100 at a first moment in time. The cathode assemblies 30 and 40 are also adapted for sputtering target material onto the substrate, wherein the substrate is to be provided to a second coating region 200 at a second moment in time. In Fig. 1, the first coating region and second coating region are separated from each other.

[0020] The embodiment shown in Fig. 1 further includes a substrate guiding system 110 for transporting the substrate into and out of the first coating region. The substrate guiding system 110 may, e.g., include a set of rollers on which a bottom part of a substantially vertically oriented substrate or substrate carrier rests and moves, and magnetic guiding system guiding an upper part of the substrate or substrate carrier. The apparatus further includes a substrate guiding system 210 for transporting the substrate into and out of the second coating region. The second substrate guiding system 210 may be the same as, or similar to, the substrate guiding system 110. The first substrate guiding system and the second substrate guiding system may be separate entities. The first substrate guiding system and the second substrate guiding system need not necessarily be physically separated, and could be formed of common parts or parts that are joined with each other. The first substrate guiding system may be a first part of one common substrate guiding system, namely the first part that is transporting substrates into and out of the first coating region, and the second substrate guiding system may be a second part of the common substrate guiding system, namely the second part that is transporting the substrates into and out of the second coating region. For instance, the second substrate guiding system may seamlessly continue the structure of the first substrate guiding system, in particular if the first coating region and the second coating region are directly adjacent to each other. For example, the first substrate guiding system 110 and the second substrate guiding system 210 may include a first and second set of rollers, respectively, wherein the first set of rollers is directly adjacent to the second set of rollers, and/or may include a magnetic guiding system or rail common to both substrate guiding systems.

[0021] For example, in the embodiment shown in Fig. 1, the substrate can be transported into the first coating region from the left-hand side of the first coating region and transported out of the first coating region at the right-hand side of the first coating region. In the embodiment shown in Fig. 1, after exiting the first coating region, the substrate can be further transported into the second coating region from the left-hand side of the second coating region and transported out of the second coating region at the right-hand side of the second coating region. As shown in Fig. 1, cathode assemblies 10 and 20 are arranged on the same side of the substrate guiding system 110, the arrangement of cathode assemblies 10 and 20 being such that the distance between the substrate guiding system 110 and the cathode assembly 10 is equal to the distance between substrate guiding system 110 and cathode assembly 20. As further shown in Fig. 1, cathode assemblies 30 and 40 are arranged on the same side of the substrate guiding system 210, the arrangement of cathode assemblies 30 and 40 being such that the distance between substrate guiding system 210 and cathode assembly 30 is equal to the distance between substrate guiding system 210 and cathode assembly 40.

[0022] The first substrate guiding system 110 defines a first substrate transport direction 120. The second substrate guiding system 210 defines a second substrate transport direction 220. The term "substrate transport direction" as used herein shall include both oriented directions in which one can move along a line. For example, the substrate transport direction 120 shall include the notion of a left-to-right movement of a substrate in Fig. 1, and also the notion of a right- to-left movement in Fig. 1 as indicated by the double-headed arrow 120.

[0023] In Fig. 1, the second substrate transport direction 220 is the same direction as the first substrate transport direction 120. The embodiment shown in Fig. 1 is an embodiment of an inline sputter deposition apparatus, wherein the direction 120 in which the substrate is transported into and out of the first coating region 100 is the same as the direction 220 in which the substrate is transported into and out of the second coating region 200.

[0024] In the embodiment shown in Fig. 1, cathode assemblies 10, 20, 30 and 40 include rotary target assemblies 11, 21, 31 and 41, having rotation axes 12, 22, 32 and 42, respectively. Each rotary target assembly shown in Fig. 1 is adapted for rotating around a rotation axis. Rotation axes 12 and 22 are parallel to each other. The line connecting the rotation axes 12 and 22 in the drawing plane is parallel to the substrate guiding system 110. Rotation axes 32 and 42 are parallel to each other. The line connecting the rotation axes in the drawing plane is parallel to the substrate guiding system 210. In particular, in the embodiment shown in Fig. 1, the rotation axes 12, 22, 32 and 42, are parallel to each other. Each of the cathode assemblies 10, 20, 30 and 40 further includes a magnet assembly. Each magnet assembly 13, 23, 33, and 43 shown in Fig. 1 is fixedly positioned within its rotatable target assembly.

[0025] Magnet assemblies 13 and 23 shown in Fig. 1 are arranged so that the target material sputtered by cathode assemblies 10 and 20, respectively, is sputtered towards the substrate guiding system 110. As further shown, magnet assemblies 33 and 43 are arranged so that the target material sputtered by cathode assemblies 30 and 40, respectively, is sputtered towards the substrate guiding system 210.

[0026] In the embodiment shown in Fig. 1, each rotary target assembly contains precisely one magnet assembly, i.e., a single magnet assembly. The position of magnet assembly 13 within cathode assembly 10 is specified by a first angle 1, wherein the first angle is the angle between a reference plane 130 and a plane 14 extending through the center of magnet assembly 13. The reference plane 130 is perpendicular to the substrate guiding system 110 and to the substrate transport direction 120, respectively. In the cross-sectional view of Fig. 1, both planes 130 and 14 are represented as lines. In the embodiment shown in Fig. 1, the first angle is a nonzero angle, e.g., an angle of about 35°. Fig. 1 further shows a plane 24 extending through the center of magnet assembly 23. In the embodiment shown in Fig. 1, the fixed arrangement of magnet assembly 13 within rotary target assembly 11 and the fixed arrangement of magnet assembly 23 within rotary target assembly 21 are such that plane 14 is parallel to plane 24.

[0027] The position of the third magnet assembly 33 shown in Fig. 1 is specified by a second angle 2, wherein the second angle is the angle between a reference plane 230 and a plane 34 which extends through the center of magnet assembly 33. The reference plane 230 is perpendicular to the substrate guiding system 210 and to the substrate transport direction 220, respectively. The reference planes 130 and 230 are parallel to each other in the embodiment shown in Fig. 1. In Fig. 1, the second angle 2 is a nonzero angle which is different from the first angle 1, e.g., is an angle of about -35°. Fig. 1 further shows a plane 44 extending through the center of magnet assembly 43. In the embodiment shown in Fig. 1, the fixed arrangement of magnet assembly 33 within rotary target assembly 30 and the fixed arrangement of magnet assembly 43 within rotary target assembly 40 are such that plane 34 is parallel to plane 44.

[0028] In Fig 1, the arrangement of the pair of cathode assemblies 30 and 40 is a mirror image of the arrangement of the pair of cathode assemblies 10 and 20. Accordingly, the first angle is a positive angle and the second angle is a negative angle, wherein the magnitude of the first angle is equal to the magnitude of the second angle.

[0029] The sputter deposition apparatus 5 shown in Fig. 1 may be used, e.g., to form a relatively thick layer of a specific material on a substrate. This relatively thick layer can be deposited in the form of two sub-layers in two different coating regions using the same target material. This is particularly advantageous where an inline apparatus is used, and other deposition processes or some other processing on substrates passing through the inline apparatus would have to wait for the process that is taking the longest time.

[0030] The fixed arrangement of the magnet assemblies has an advantage, compared to a rotatable magnet assembly, in that no magnet drive is necessary. This lowers the complexity, maintenance efforts and costs considerably. Another advantage can be that there is no time loss due to movement of the magnet assembly.

[0031] Further, an advantage of a cathode assembly having a single magnet assembly and not more is an increased stability of operation in connection with the plasma of the sputter deposition process. Cathode assemblies using two or more magnet assemblies per cathode assembly may lead to unstable process conditions.

[0032] The different fixed angles of the magnet assemblies in the first and second coating regions provide for an increased uniformity of a layer containing a first sub-layer sputtered in the first coating region and a second sub-layer sputtered in the second coating region, in particular if the different angles are mirror- images of each other. Cathode assemblies having a magnet assembly which is rotatable around a rotary axis may also provide for the deposition of a homogeneous layer of material on the substrate, wherein the rotation around the rotary axis may be provided in a wobbling mode or in a split sputter mode. But, the rotary magnet assemblies are more complicated as they need drives, controllers and the like, and the throughput may be lower, in particular in an inline sputter deposition apparatus.

[0033] According to embodiments described herein, a sputter deposition apparatus for coating a substrate is provided. The sputter deposition apparatus has two or more coating regions for coating the substrate. According to some embodiments, the sputter deposition apparatus is adapted for coating the substrate by static deposition processes taking place in the two or more coating regions.

[0034] The distinction between static deposition and dynamic deposition is the following, and applies particularly for large area substrate processing, such as processing of vertically oriented large area substrates. A dynamic sputtering is an inline process where the substrate moves continuously or quasi-continuously adjacent to the deposition source. Dynamic sputtering has the advantage that the sputtering process can be stabilized prior to the substrates moving into a deposition area, and then held constant as substrates pass by the deposition source. Yet, a dynamic deposition can have disadvantages, e.g. with respect to particle generation. This might particularly apply for TFT backplane deposition. It should be noted that the term static deposition process, which is different as compared to dynamic deposition processes, does not exclude every movement of the substrate as would be appreciated by a skilled person. A static deposition process can include, for example, a static substrate position during deposition, an oscillating substrate position during deposition, an average substrate position that is essentially constant during deposition, a dithering substrate position during deposition, a wobbling substrate position during deposition, or a combination thereof. Accordingly, a static deposition process can be understood as a deposition process with a static position, a deposition process with an essentially static position, or a deposition process with a partially static position of the substrate. Thereby, a static deposition process, as described herein, can be clearly distinguished from a dynamic deposition process without the necessity that the substrate position for the static deposition process is fully without any movement of the substrate or of the cathode assemblies during deposition.

[0035] According to embodiments, the two or more coating regions are separate coating regions. In other words, the coating regions do not overlap with each other. The coating regions may be at a certain distance from each other. They may be separated from each other by separation walls, wherein the separation walls may be the inner walls of one coating chamber or the exterior walls of more than one coating chamber, e.g., the exterior walls of two adjacent coating chambers. A coating chamber may contain one or more coating regions that are separated from each other.

[0036] According to some embodiments, which can be combined with other embodiments described herein, the sputter deposition apparatus is an inline apparatus. An inline apparatus may include two or more coating regions arranged along a substrate transport path. The substrate transport path may be straight, and the coating regions may be arranged substantially along a straight line, but the substrate transport path could have curves. More than one substrate transport path may pass through a coating region, e.g., a forward and a return path. An example of an inline sputter deposition apparatus is shown in Fig 1, where the first coating region 100 and the second coating region 200 are arranged along a straight line.

[0037] An operational mode of an inline sputter deposition apparatus may include guiding and/or transporting the substrate along at least one substrate transport path through the coating regions of the sputter deposition apparatus, wherein the substrate is sequentially processed in the coating regions of the sputter deposition apparatus. In an inline sputter deposition process, the movement of a substrate along the line of coating regions may include: a movement along the line of coating regions in both oriented directions, such as forward and back and/or a movement with interruptions, such that at times the substrate may be moved and at other times the substrate may be held still, in particular for coating the substrate. In some embodiments, which can be combined with other embodiments, a static deposition process takes place in some or all coating regions along the line of coating regions.

[0038] The sputter deposition apparatus includes: a first substrate guiding system, e.g., the substrate guiding system 110 shown in Fig. 1, for guiding the substrate in a first coating region, the first substrate guiding system defining a first substrate transport direction. The first substrate transport direction may, e.g., be the direction 120 in Fig. 1. The sputter deposition apparatus further includes a second substrate guiding system, e.g., the substrate guiding system 210 shown in Fig. 1, for guiding the substrate in a second coating region, the second substrate guiding system defining a second substrate transport direction. The second substrate transport direction may, e.g., be the direction 220 in Fig. 1. According to embodiments, which can be combined with other embodiments described herein, the second substrate transport direction is the same direction as the first substrate transport direction or is different from the first substrate transport direction. In some embodiments, in particular in inline sputter deposition apparatuses, the first substrate transport direction and the second substrate transport direction lie along the substrate transport path, and the two directions may be equal.

[0039] According to embodiments described herein, the sputter deposition apparatus includes a first cathode assembly adapted for generating one or more plasma regions in the first coating region. The first cathode assembly includes a first rotary target assembly adapted for rotating a target material around a first rotation axis, and a first magnet assembly fixedly positioned in the first rotary target assembly, the first magnet assembly having a first principal plane forming a first angle with a first reference plane which contains the first rotation axis and is perpendicular to the first substrate transport direction. The first principal plane may, e.g., be the plane 14 in Fig. 1, and the first reference plane may e.g. be the plane 130.

[0040] According to embodiments described herein, the sputter deposition apparatus includes a second cathode assembly adapted for generating one or more plasma regions in the first coating region. The second cathode assembly comprises a second rotary target assembly adapted for rotating a target material around a second rotation axis. The second rotation axis may be parallel to the first rotation axis. A second magnet assembly is fixedly positioned in the second rotary target assembly. The second magnet assembly has a second principal plane being substantially parallel or parallel to the first principal plane. The second principal plane may, e.g., be the plane 24 in Fig. 1. Two planes are considered substantially parallel if they form an angle of not more than ±5°.

[0041] The sputter deposition apparatus includes a third cathode assembly adapted for generating one or more plasma regions in the second coating region. The third cathode assembly includes a third rotary target assembly adapted for rotating a target material around a third rotation axis. A third magnet assembly is fixedly positioned in the third rotary target assembly. The third magnet assembly has a third principal plane forming a second angle with a second reference plane which contains the third rotation axis and is perpendicular to the second substrate transport direction. The third principal plane may, e.g., be the plane 34 in Fig. 1, and the second reference plane may, e.g., be the plane 230. The second angle is different from the first angle. The sputter deposition apparatus includes a fourth cathode assembly adapted for generating one or more plasma regions in the second coating region. The fourth cathode assembly includes a fourth rotary target assembly adapted for rotating a target material around a fourth rotation axis. The fourth rotation axis may be parallel to the third rotation axis. A fourth magnet assembly is fixedly positioned in the fourth rotary target assembly. The fourth magnet assembly has a fourth principal plane, which can, e.g., be the plane 44 in Fig. 1. The fourth principal plane is substantially parallel or parallel to the third principal plane.

[0042] According to some embodiments, the first magnet assembly is the only magnet assembly positioned in the first rotary target assembly, the second magnet assembly is the only magnet assembly positioned in the second rotary target assembly, the third magnet assembly is the only magnet assembly positioned in the third rotary target assembly, and the fourth magnet assembly is the only magnet assembly positioned in the fourth rotary target assembly.

[0043] The provision that the first, second, third and fourth magnet assemblies, or any other magnet assembly in the first or second coating region, are fixedly positioned in their respective rotary target assemblies, shall be understood in the following sense. The position of a magnet assembly within its rotary target assembly remains fixed throughout at least the deposition process of a substrate, and can remain fixed throughout a deposition cycle of several substrates coated under the same process conditions. There may be no motor for rotating the magnet assembly with respect to its rotary target assembly. The magnet assembly may be rigidly attached to the cathode assembly. The rigidly attached magnet assembly may be detachable for adjusting the position and/or orientation of the principal plane of the magnet assembly. For instance, the position of the magnet assembly may be adjusted across different deposition cycles, which may take place at different moments in time and which may have different process parameters, e.g., a different target material. This is to be understood in contrast to a situation in which the magnet assembly has a varying position during one and the same deposition process on a substrate, such as a continuous wobbling movement of the magnet during sputtering of a substrate. In some embodiments, the position of a magnet assembly in its rotary target assembly may be adapted in dependence of the target material which is mounted on the rotary target assembly. For example, in a first deposition cycle taking place in the first coating region, a first target material may be used and, accordingly, the position of the first magnet assembly may be a first position, wherein the first position remains fixed throughout the first deposition cycle; and in a second deposition cycle taking place in the first coating region, a second target material may be used and, accordingly, the position of the first magnet assembly may be a second position, wherein the second position remains fixed throughout the second deposition cycle.

[0044] According to some embodiments, which can be combined with other embodiments described herein, the first, second, third and fourth rotary target assemblies are adapted for rotating in a rotational direction, wherein the rotational direction may be selected from clockwise and counterclockwise independently for each of the first, second, third and fourth rotary target assemblies.

[0045] According to some embodiments, which may be combined with other embodiments described herein, the first and second rotary target assemblies may rotate in the same rotational direction, e.g. the first and second rotary target assembly may both rotate clockwise. According to other embodiments, which may be combined with other embodiments described herein, the first and second rotary target assemblies may rotate in opposite rotational directions of a sputter deposition process, e.g. the first rotary target assembly may rotate clockwise and the second rotary target assembly may rotate counterclockwise. Similarly, the third and fourth rotary target assemblies may rotate in the same rotational direction, e.g. the third and fourth rotary target assembly may both rotate clockwise. According to other embodiments, which may be combined with other embodiments described herein, the third and fourth rotary target assemblies may rotate in opposite rotational directions of a sputter deposition process, e.g. the third rotary target assembly may rotate clockwise and the fourth rotary target assembly may rotate counterclockwise.

[0046] According to some embodiments, which can be combined with other embodiments described herein, the rotational direction of a cathode assembly, such as the rotational direction of the first, second, third and/or fourth cathode assembly, can be reversed within a sputtering process of a substrate. A cathode assembly may have a first rotational direction during the first half of the sputtering process of a substrate, and a second rotational direction different from the first rotational direction during the second half of the same sputtering process of a substrate. For example, the first rotary target assembly may initially rotate clockwise and then counterclockwise.

[0047] Fig. 2 shows an embodiment of a sputter deposition apparatus. As illustrated in the enlarged view of magnet assembly 23, magnet assembly 23 has an inner south pole 231 and two outer north poles 232. The inner and outer poles extend out of the body 233 of magnet assembly 23. Body 233 is perpendicular to the longitudinal extension of the poles 231, 232 and connects them at a base end. The cross-sectional view of magnet assembly 23 as shown in Fig. 2 has the shape of a fork, wherein the prongs of the fork represent the inner and outer poles. As further shown, the inner and outer poles face an inner surface of rotatable target assembly 21. The inner magnet pole 231 further has a center plane 234 which coincides with plane 24. A shown in Fig. 2, the center plane 234, which is in a cross-sectional view represented as a line, runs through the center of the inner pole 231 in a direction parallel to the direction in which the inner pole extends. Both outer poles 232 shown in Fig. 2 extend in directions parallel to the plane 24 and are separated from the center plane 234 by a distance.

[0048] In the embodiment of Fig. 2, the cathode assemblies 10 and 20, the substrate guiding system 110 and the first coating region 100 are in a first coating chamber 140, and the cathode assemblies 30 and 40, the second substrate guiding system 210 and the second coating region 200 are in a second coating chamber 240. The coating chambers 140 and 240 are adjacent coating chambers separated by a separation wall 6. As shown, the coating chambers 140 and 240 are connected to each other by a valve 7 disposed in separation wall 6, allowing substrates to pass from the coating chamber 140 to the coating chamber 240 and vice versa. The valve 7 may be a vacuum sealable valve. A vacuum sealable valve can be selected from the group consisting of: a slit valve, a sluice valve, and a gate valve.

[0049] Having the two coating regions in separate coating chambers has the advantage that no cross-contamination can occur between substrates that are disposed in different coating chambers. Another advantage is that process parameters, such as e.g. pressure or composition of process gases, can be tuned individually per coating chamber. Especially in inline coating systems, the sputtering of thick layers may be carried out in two or more coating chambers, each sputtering a part of the thick layer. Thus the time that substrates spend in different coating chambers can be made more equal, and waiting times of substrates can be reduced, thereby increasing the throughput.

[0050] According to embodiments described herein, a magnet assembly, such as the first, second, third and fourth magnet assembly, has a principal plane, such as the first, second, third and fourth principal plane, respectively. A magnet assembly as described herein may include an inner magnet pole with a center plane that coincides with the principal plane of the magnet assembly, and at least one outer magnet pole separated by a distance from the principal plane of the magnet assembly. For example, in Fig. 2, magnet assembly 20 may be regarded as the second magnet assembly, pole 231 as an inner pole and pole 232 as an outer pole, plane 234 may as the center plane of the second magnet assembly and plane 24 as the second principal plane, which coincides with the center plane of the second magnet assembly.

[0051] The principal plane of a magnet assembly may be perpendicular to a body of the magnet assembly. The body may connect the poles, and may be perpendicular to the direction of longest extension of the poles, i.e., their longitudinal extension. The principal plane may be a plane of mirror symmetry of the magnet assembly. In some embodiments, the inner and outer poles of a magnet assembly extend outward from the body of the magnet assembly, wherein the principal plane of the magnet assembly runs longitudinally through the center of the inner magnet pole.

[0052] The inner and outer poles of a magnet assembly may be on the same side of the body of the magnet assembly. The magnet assembly may be positioned within its rotatable target assembly so that one or more poles face an inner surface of the rotatable target assembly. According to some embodiments, a magnet assembly has two outer poles of equal polarity and one inner pole of opposite polarity.

[0053] In some embodiments, which can be combined with other embodiments described herein, the first angle is a positive angle relative to the first reference plane, and the second angle is a negative angle relative to the second reference plane. The first and second reference plane may be parallel. The first angle may be a nonzero angle. The first angle may have a value in the range from 0° to 60°, specifically in a range from 5° to 50°, more specifically in a range from 10° to 40°, such as about 15°, 25° or 35°. The second angle may be a nonzero angle. The second angle may have a value in the range from 0° to -60°, specifically in a range from -5° to -50°, more specifically in a range from -10° to -40°, such as about -15°, -25° or - 35°. The absolute value of the difference of the first and second angles may be larger than 5°, 10°, 20° or 30°. More specifically, the absolute value of the difference of the first and second angles may be larger than 40°, 50° or even larger than 60°. This absolute value of the difference of the first and second angles corresponds to the angle between the first principal plane and the third principal plane if the first and second substrate guiding systems are parallel to each other. The first angle and the second angle may have equal magnitudes, i.e., the values of the first angle and of the second angle may be the same when taken as absolute values. The magnitudes may be substantially the same, i.e., deviating by not more than ±5°.

[0054] According to some embodiments, which can be combined with other embodiments described herein, a sputter deposition apparatus includes a first coating chamber and a second coating chamber. The first coating region is in the first coating chamber, and the second coating region is in the second coating chamber. The first and second cathode assemblies are positioned in the first coating chamber, and the third and fourth cathode assemblies are positioned in the second coating chamber. Any of the coating chambers may be a vacuum chamber. A vacuum chamber includes one or more valves, which may connect the chamber to another chamber. After a substrate has been guided into the vacuum chamber, the one or more valves can be closed. Accordingly, the atmosphere in the vacuum chamber can be controlled by generating a technical vacuum, for example, with vacuum pumps, and/or by inserting process gases in the chamber. [0055] Figs. 3a and 3b illustrate an embodiment of a method for coating a substrate in two coating regions at two moments in time. Fig. 3a shows a substrate 50 being coated in the coating region 100 of the first coating chamber 140 at a first moment in time. The substrate 50 is guided by the substrate guiding system 110. Target material is sputtered onto the substrate 50 at a first sputtering angle 1100. The substrate is a planar substrate, and the substrate is parallel to the substrate guiding system 110. Plasma regions 15 and 25 are generated by cathode assemblies 10 and 20, respectively. Plasma region 15 is formed near a magnetic field (not shown) generated by magnet assembly 13. Plasma region 25 is formed near a magnetic field (not shown) generated by magnet assembly 23. A target material is sputtered away from cathode assemblies 10 and 20 towards the substrate, and the direction in which target material is sputtered by cathode assembly 10 is equal to the direction in which target material is sputtered by cathode assembly 20, as indicated by the arrows shown in Fig. 3a.

[0056] In the embodiment shown in Fig. 3a, the angle between the substrate and the plane 14 extending through the center of magnet assembly 13 is equal to the angle between the substrate and the plane 24 extending through the center of magnet assembly 23. Accordingly, the first sputtering angle 1100, being the angle at which target material from cathode assembly 10 is sputtered onto the substrate, is equal to the angle at which target material from cathode assembly 20 is sputtered onto the substrate. Furthermore in Fig. 3a the first sputtering angle is a negative angle, and the relation between the first sputtering angle and the first angle 1 is as follows: the first sputtering angle plus 90 degrees equals the first angle. In other words, the first angle 1 and the first sputtering angle 1100 are complementary angles.

[0057] Further, in the embodiment shown in Fig 3a, the second coating chamber 240 is shown without any substrate for ease of explanation. In an inline processing system, the second coating chamber would often contain a different substrate that already has undergone treatment in the first chamber at an earlier instance of time.

[0058] Fig 3b shows a second coating chamber in which a second sputtering process takes place at a second moment in time. The substrate 50 is guided by the substrate guiding means 210 and is parallel thereto. In the time between the situations shown in Figs. 3a and 3b, the substrate may have been transported by substrate guiding system 110 out of the first chamber, and by substrate guiding system 210 into the second chamber. While the first chamber 140 is shown without any further substrate in the first chamber for ease of explanation, the first chamber 140 would often contain a further substrate that would be coated simultaneously.

[0059] In Fig 3b, the substrate is in the second coating region 200. In the second sputtering process illustrated in Fig 3b, target material of the same kind is sputtered onto the substrate 50 at a second sputtering angle 2100 which is different from the first sputtering angle. Plasma regions 35 and 45 are generated by cathode assemblies 30 and 40, respectively. Plasma region 35 is formed near a magnetic field (not shown) generated by magnet assembly 33. Plasma region 45 is formed near a magnetic field (not shown) generated by magnet assembly 43. The target material is sputtered away from cathode assemblies 30 and 40 towards the substrate. As shown, the direction in which target material is sputtered by cathode assembly 30 is equal to the direction in which target material is sputtered by cathode assembly 40, as indicated by the arrows shown in Fig. 3b.

[0060] In the embodiment shown in Fig. 3b, the angle between the substrate and the plane 34 extending through the center of magnet assembly 33 is equal to the angle between the substrate and the plane 44 extending through the center of magnet assembly 43. Accordingly, the second sputtering angle 2100, being the angle at which target material from cathode assembly 30 is sputtered onto the substrate, is equal to the angle at which target material from cathode assembly 40 is sputtered onto the substrate. Furthermore, as shown in Fig. 3b, the second sputtering angle 2100 is a negative angle, and the relation between the second sputtering angle 2100 and the second angle 2 is as follows: the second sputtering angle plus 90 degrees equals the second angle. In other words, the second angle 2 and the second sputtering angle 2100 are complementary angles.

[0061] The first sputtering angle 1100 shown in Fig. 3a is different from the second sputtering angle 2100 shown in Fig. 3b. As shown in Fig 3a, the magnitude of the first sputtering angle is smaller than 90 degrees and, as shown in Fig. 3b, the magnitude of the second sputtering angle is larger than 90 degrees. The magnet assemblies 33, 43 in the second chamber 240 are arranged mirror- symmetric with respect to the magnet assemblies 13, 23 in the first chamber 140, the plane of symmetry being a plane extending up-down in the drawing plane of Figs. 3a and 3b. The magnitudes of the first sputtering angel 1100 and of the second sputtering angle 2100 add up to 180°. In other words, the sputtering angles behave like supplementary angles.

[0062] Two coating chambers as described herein may be used, e.g., to deposit thick layers of material for reasons related to throughput and uptime. Accordingly, embodiments which include two coating chambers having different process parameters, such as the embodiments shown in Fig. 2, 3a-b and 4a-b wherein the first angle is different from the second angle, provide for uniform coatings in a cost effective and time-effective way.

[0063] The present disclosure is particularly directed at the coating of large area substrates. A coating chamber, in particular where large area substrates are to be coated, may include a plurality of cathode assemblies, each having a rotatable target assembly and a magnet assembly. Such a situation is illustrated in Figs. 4a-b. [0064] Figs. 4a-b show a first coating chamber 140 and second coating chamber 240, wherein exemplarily the first coating chamber comprises six cathode assemblies 10, 20, 311, 321, 331 and 341 and the second coating chamber comprises six cathode assemblies 30, 40, 312, 322, 332 and 342. Figs 4a-4b further show magnet assemblies 411, 421, 431, 441, 412, 422, 432 and 442 arranged within cathode assemblies 311, 321, 331, 341, 312, 322, 332 and 342, respectively. Each cathode assembly shown in Fig. 4a has one single magnet assembly i.e. precisely one magnet assembly and not more. Each cathode assembly shown in Fig. 4b has one single magnet assembly i.e. precisely one magnet assembly and not more. The cathode assemblies 311, 321, 331, 341, 312, 322, 332 and 342 further have planes 511, 521, 531, 541, 512, 522, 532 and 542, respectively, extending through the centers of magnet assemblies 411, 421, 431, 441, 412, 422, 432 and 442, respectively. As shown, the planes 511, 521, 531 and 541 are parallel to the plane 14 and the planes 512, 522, 532 and 542 are parallel to plane 34.

[0065] In Fig. 4a, target material is sputtered away from cathode assemblies 10, 20 311, 321, 331 and 341 towards the substrate. As shown, the direction in which target material is sputtered by cathode assembly 10 is equal to the direction in which target material is sputtered by cathode assemblies 20, 311, 321, 331 and 341, respectively. The first sputtering 1100 angle is equal to the angle at which target material from cathode assemblies 311, 321, 331 and 341, respectively, is sputtered onto the substrate surface, and is the same for the target material sputtered from each of the cathode assemblies in the first chamber 140 in Fig. 4a. In Fig. 4b, target material is sputtered away from cathode assemblies 30, 40, 312, 322, 332 and 342 towards the substrate. As shown, the direction in which target material is sputtered by cathode assembly 30 is equal to the direction in which target material is sputtered by cathode assemblies 40, 312, 322, 332 and 342, respectively. The second sputtering angle 2100 is equal to the angle at which target material from cathode assemblies 312, 322, 332 and 342, respectively, is sputtered onto the substrate surface, and is the same for the target material sputtered from each of the cathode assemblies in the second chamber 240 in Fig. 4b. An advantage of having more than two cathode assemblies in a coating region or in a chamber, respectively, is a more uniform and homogenous coating, in particular for large area substrates.

[0066] Figs 4a and 4b exemplarily show power supplies 611, 621, 631, 641, 651, 661, 612, 622, 632, 642, 652 and 662 which are used in some embodiments for biasing cathode assemblies 10, 20, 311, 321, 331, 341, 30, 40, 312, 322, 332 and 342, respectively. Fig 4a and 4b further show exemplarily anode bars 711, 721, 731, 741 and 751 positioned between the cathode assemblies 10, 20, 311, 321, 331 and 341. Fig 4a and 4b further show exemplarily anode bars 712, 722, 732, 742 and 752 positioned between the cathode assemblies 30, 40, 312, 322, 332 and 342. [0067] The cathode assemblies 10, 20, 311, 321, 331 and 341 shown in Figs 4a and 4b are not arranged equidistantly with respect to the substrate but along an arc shape. The curvature of the arc-shaped cathode arrangement is such that the outer cathodes 10 and 341 on the arc are farther away from the substrate compared to inner cathodes 311 and 321 on the arc. Analogously, cathode assemblies 30, 40, 312, 322, 332 and 342 shown in Figs 4a and 4b are arranged along an arc shape. Under some process conditions, such an arc-shaped cathode arrangement may achieve a higher degree of uniformity of the coating, in particular at the edges of the substrate, as compared to cathodes which are arranged equidistantly from the substrate.

[0068] According to some embodiments, which may be combined with other embodiments, the first coating region, the second coating region, or any other coating region may be associated with a plurality of cathode assemblies. In particular, the first coating chamber, the second coating chamber, or any other coating chamber may each include a plurality of cathode assemblies. The cathode assemblies associated with a coating region or contained in coating chamber may be arranged in an array. In particular, for static large-area substrate deposition, a one-dimensional array of cathode assemblies may be provided, where one- dimensional is to be understood in relation to a cross-section similar as shown in Figs. l-4b. The cathode assemblies in the array may be regularly arranged, in particular at a substantially even spacing from each other. The number of cathode assemblies may be between 2 and 18, more specifically between 4 and 16 per coating chamber or coating region, e.g., 5, 6, 7, 8, 9, 10, 11, 12 or more than 12 cathode assemblies per chamber or per coating region.

[0069] The length of a rotatable target assembly, such as the first, second, third, fourth or any other rotary target assembly of the sputter deposition apparatus, may be slightly larger than the length of the substrate to be coated. Additionally or alternatively, a cathode array associated with a coating region or contained in coating chamber may be slightly broader than the width of the substrate. "Slightly" includes a range of between 100% and 110%. The provision of a slightly larger coating length/width helps avoiding boundary effects.

[0070] In some embodiments, which can be combined with other embodiments described herein, a plurality of cathode assemblies associated with a coating region or contained in coating chamber is arranged not in an equidistant fashion with respect to the substrate but along an arc shape. The shape of the arc may be such that the inner cathode assemblies are located closer to the substrate than the outer cathode assemblies. Such a situation is schematically shown in Figs. 4a and 4b. Alternatively, it is also possible that the shape of the arc defining the positions of the plurality of cathode assemblies is such that the outer cathode assemblies are located closer to the substrate than the inner cathode assemblies. The scattering behavior depends on the material to be sputtered. Hence, depending on the application, i.e. on the material to be sputtered, providing the cathode assemblies on an arc shape will further increase the homogeneity. The orientation of the arc depends on the application.

[0071] Figs 5a and 5b illustrate a method of coating a substrate in a first coating region 100 and in a separate second coating region 200, at different moments in time. Fig. 5a shows the substrate being in the first coating region 100 at a first moment in time. A first target material is sputtered onto a surface 51 of the substrate in the first coating region at a first sputtering angle 1100 relative to the substrate surface, as indicated by the arrows. The first coating region 100 may be located in a first chamber.

[0072] Fig. 5b shows the substrate being in the second coating region at a second moment in time. A second target material is sputtered onto the surface in the second coating region at a second sputtering angle 2100 relative to the substrate surface. In the example of Figs. 5a and 5b, the second target material is the same as the first target material, e.g., in order to deposit a thick layer in two deposition processes. The first sputtering angle 1100 shown in Fig. 5a is different from the second sputtering angle 2100 shown in Fig 5b. The second coating region 200 may be located in a second chamber.

[0073] According to embodiments, a method of coating a substrate is provided. The reference signs refer to the schematic flow diagram shown in Fig. 6. The method may include depositing a layer of material onto a surface of the substrate in two or more deposition processes. Sub-layers of the material can be successively deposited onto the substrate in two or more processes, such that the final layer of material deposited on the substrate is the total of the sub-layers.

[0074] The method includes providing the substrate to a first coating region, as illustrated in Fig. 6 with reference number 1000. The method further includes sputtering a surface of the substrate with a first target material, the first target material being sputtered onto the surface in the first coating region at a first sputtering angle relative to the substrate surface, as illustrated in Fig. 6 with reference number 2000. The first sputtering angle is the only angle at which a target material is sputtered onto the substrate surface throughout the sputtering process in the first coating region. The method further includes providing the substrate to the second coating region, as illustrated in Fig. 6 with reference number 3000. The method further includes sputtering the surface of the substrate with a second target material, the second target material being equal to the first target material or different from the first target material, as illustrated in Fig. 6 with reference number 4000. The second target material is sputtered onto the surface in the second coating region at a second sputtering angle relative to the substrate surface. The first sputtering angle and the second sputtering angle are different, and the second sputtering angle is the only angle at which a target material is sputtered onto the substrate surface throughout the sputtering process in the second coating region. [0075] According to some embodiments, the coating method relates to an inline sputter deposition process. In an inline sputter deposition process, the first and second coating regions may be disposed along a substrate transport path, such as a straight line, and the coating method may include guiding and/or transporting the substrate along the substrate transport path into the first coating region, out of the first coating region, into the second coating region and out of the second coating region. The transport of the substrate along the substrate transport path on which the first and second coating regions are disposed, may be a transport with interruptions, so that at times the substrate is transported and at other times, in particular during sputtering, the substrate is static or oscillating or the like. Movements may take place along both oriented directions along this path. There may be more than one substrate transport path, e.g., a forward and a return path leading through the coating regions. The substrate may be vertically oriented or substantially vertically oriented throughout the coating process. The substrate is substantially vertically oriented if its inclination with respect to the vertical direction is smaller than + 25°, or even smaller than ±15°, e.g., smaller than ±10°. The sputtering processes taking place in the first and second coating regions are static sputter deposition process in some embodiments.

[0076] According to some embodiments, which can be combined with other embodiments described herein, the magnitude of the first sputtering angle lies in the range from 30° to 90° and the magnitude of the second sputtering angle lies in the range from 90° to 150°. The first sputtering angle may be different from 90° and the second sputtering angle may be different from 90°. The magnitude of the first sputtering angle may have a value in the range from 30° to 90°, specifically in a range from 40° to 85°, more specifically in a range from 50° to 80°, such as about 55°, 65° or 75°. The magnitude of the second sputtering angle may have a value in the range from 90° to 150°, specifically in a range from 95° to 140°, more specifically in a range from 100° to 130°, such as about 105°, 115° or 125°. According to some embodiments, the sum of the magnitude of the first sputtering angle and the magnitude of the second sputtering angle is 180 degrees.

[0077] According to some embodiments, the coating method is carried out with a sputter deposition apparatus according to embodiments described herein. In some embodiments, the first sputtering angle is equal to the angle between the first substrate transport direction and the first principal plane, and the first sputtering angle is at the same time equal to the angle between the first substrate transport direction and the second principal plane. In some embodiments, the second sputtering angle is equal to the angle between the second substrate transport direction and the third principal plane, and the second sputtering angle is at the same time equal to the angle between the second substrate transport direction and the fourth principal plane. [0078] According to some embodiments, which can be combined with other embodiments described herein, the first angle determines the first sputtering angle. The relation between these two angles may be as follows: the first sputtering angle plus 90° equals the first angle. According to some embodiments, the second angle determines the second sputtering angle. The relation between these two angles may be as follows: the second sputtering angle plus 90° equals the second angle.

[0079] According to some embodiments of the coating method described herein, which can be combined with other embodiments described herein, the first coating region is contained in a first coating chamber and the second coating region is contained in a second coating chamber.

[0080] The term "substrate" as used herein embraces both inflexible substrates, e.g., a glass substrate, a wafer, slices of transparent crystal such as sapphire or the like, or a glass plate, and flexible substrates, such as a web or a foil. According to some embodiments, which can be combined with other embodiments described herein, embodiments described herein can be utilized for Display PVD, i.e. sputter deposition on large area substrates for the display market. According to some embodiments, large area substrates or respective carriers, wherein the carriers may carry one substrate or a plurality of substrates, may have a size of at least 0.67 m². The size may be from about 0.67m (0.73x0.92m - Gen 4.5) to about 8 m², more specifically from about 2 m² to about 9 m² or even up to 12 m². The substrates or carriers, for which the structures, apparatuses, such as cathode assemblies, and methods according to embodiments described herein are provided, can be large area substrates as described herein. For instance, a large area substrate or carrier can be GEN 4.5, which corresponds to about 0.67 m² substrates (0.73x0.92m), GEN 5, which corresponds to about 1.4 m² substrates (1.1 m x 1.3 m), GEN 7.5, which corresponds to about 4.29 m² substrates (1.95 m x 2.2 m), GEN 8.5, which corresponds to about 5.7m² substrates (2.2 m x 2.5 m), or even GEN 10, which corresponds to about 8.7 m² substrates (2.85 m x 3.05 m). Even larger generations such as GEN 11 and GEN 12 and corresponding substrate areas can similarly be implemented.

[0081] According to some embodiments, which can be combined with other embodiments described herein, target material can be selected from the group including or consisting of: aluminum, silicon, tantalum, molybdenum, niobium, titanium, copper and oxides, nitrides, oxi-nitrides and alloys thereof. Particularly, the target material can be selected from the group including or consisting of aluminum, copper and silicon. Reactive sputter processes can provide deposited oxides of these target materials. Sputter materials also include ITO (Indium- Tin-Oxide), IZO (Indium-Zinc-Oxide), IGZO (Indium-Gallium-Zinc-Oxide), AZO (Aluminum-doped Zinc-Oxide). These materials may be sputtered in a partly reactive manner. Nitrides or oxi-nitrides might be deposited as well. Process gases for sputtering target materials, that may be used in connection with embodiments described herein, can include inert gases such as argon and/or reactive gases such as oxygen, nitrogen, hydrogen and ammonia (NH3), Ozone (03), activated gases or the like.

[0082] When referring to the "homogeneity" of a layer of deposited material, this shall be mainly understood as the uniformity of the layer thickness throughout the coated area on the substrate, the crystal structure, the specific resistance and the stress of the layer.

[0083] While the foregoing is directed to some embodiments, other and further embodiments may be devised without departing from the scope determined by the claims that follow.

Claims

1. A sputter deposition apparatus for coating a substrate (50), the sputter deposition apparatus having two or more coating regions for coating the substrate, the sputter deposition apparatus comprising: a first substrate guiding system (110) for guiding the substrate in a first coating region (100), the first substrate guiding system defining a first substrate transport direction (120); a second substrate guiding system (210) for guiding the substrate in a second coating region (200), the second substrate guiding system defining a second substrate transport direction (220), wherein the second substrate transport direction is the same direction as the first substrate transport direction or is different from the first substrate transport direction; a first cathode assembly (10) adapted for generating one or more plasma regions in the first coating region, the first cathode assembly comprising: a first rotary target assembly (11) adapted for rotating a target material around a first rotation axis (12), and a first magnet assembly (13) fixedly positioned in the first rotary target assembly, the first magnet assembly having a first principal plane (14) forming a first angle (1) with a first reference plane (130) which contains the first rotation axis and is perpendicular to the first substrate transport direction; a second cathode assembly (20) adapted for generating one or more plasma regions in the first coating region, the second cathode assembly comprising: a second rotary target assembly (21) adapted for rotating a target material around a second rotation axis (22), and a second magnet assembly (23) fixedly positioned in the second rotary target assembly, the second magnet assembly having a second principal plane (24), the second principal plane being parallel to the first principal plane; a third cathode assembly (30) adapted for generating one or more plasma regions in the second coating region, the third cathode assembly comprising: a third rotary target assembly (31) adapted for rotating a target material around a third rotation axis (32), and a third magnet assembly (33) fixedly positioned in the third rotary target assembly, the third magnet assembly having a third principal plane (34) forming a second angle (2) with a second reference plane (230) which contains the third rotation axis and is perpendicular to the second substrate transport direction, wherein the second angle is different from the first angle; a fourth cathode assembly (40) adapted for generating one or more plasma regions in the second coating region, the fourth cathode assembly comprising: a fourth rotary target assembly (41) adapted for rotating a target material around a fourth rotation axis (42), and a fourth magnet assembly (43) fixedly positioned in the fourth rotary target assembly, the fourth magnet assembly having a fourth principal plane (44), the fourth principal plane being parallel to the third principal plane.

2. The sputter deposition apparatus according to claim 1, wherein the first magnet assembly is the only magnet assembly positioned in the first rotary target assembly, the second magnet assembly is the only magnet assembly positioned in the second rotary target assembly, the third magnet assembly is the only magnet assembly positioned in the third rotary target assembly, and the fourth magnet assembly is the only magnet assembly positioned in the fourth rotary target assembly.

3. The sputter deposition apparatus according to claim 1 or claim 2, further comprising a first coating chamber (140) and a second coating chamber (240), the first coating region being in the first coating chamber, the second coating region being in the second coating chamber, the first and second cathode assembly being positioned in the first coating chamber, the third and fourth cathode assembly being positioned in the second coating chamber.

4. The sputter deposition apparatus according to any of the preceding claims, wherein the first angle is a positive angle relative to the first reference plane, and the second angle is a negative angle relative to the second reference plane.

5. The sputter deposition apparatus according to claim 4, wherein the first angle and the second angle have equal magnitudes.

6. The sputter deposition apparatus according to claim 4 or claim 5, wherein the first angle is in the range from 0 degrees to 60 degrees, and the second angle is in the range from 0 degrees to -60 degrees.

7. The sputter deposition apparatus according to any of the preceding claims, wherein the first magnet assembly comprises an inner magnet pole with a center plane that coincides with the first principal plane, and at least one outer magnet pole separated by a distance from the first principal plane; the second magnet assembly comprises an inner magnet pole (231) with a center plane (234) that coincides with the second principal plane, and at least one outer magnet pole (232) separated by a distance from the second principal plane; the third magnet assembly comprises an inner magnet pole with a center plane that coincides with the third principal plane, and at least one outer magnet pole separated by a distance from the third principal plane; the fourth magnet assembly comprises an inner magnet pole with a center plane that coincides with the fourth principal plane, and at least one outer magnet pole separated by a distance from the fourth principal plane.

8. The sputter deposition apparatus according to any of the preceding claims, wherein the first, second, third and fourth rotary target assemblies are adapted for rotating in a rotational direction, wherein the rotational direction is selected from clockwise and counterclockwise independently for each of the first, second, third and fourth rotary target assemblies.

9. A method of coating a substrate in a first coating region and in a separate second coating region, the method comprising: providing the substrate to the first coating region; sputtering a surface (51) of the substrate with a first target material, the first target material being sputtered onto the surface in the first coating region at a first sputtering angle (1100) relative to the substrate surface, the first sputtering angle being the only angle at which a target material is sputtered onto the substrate surface throughout the sputtering process in the first coating region; providing the substrate to the second coating region; sputtering the surface of the substrate with a second target material, the second target material being equal to the first target material or different from the first target material, the second target material being sputtered onto the surface in the second coating region at a second sputtering angle (2100) relative to the substrate surface, the first sputtering angle and the second sputtering angle being different, and the second sputtering angle being the only angle at which a target material is sputtered onto the substrate surface throughout the sputtering process in the second coating region.

10. The method according to claim 9, wherein the magnitude of the first sputtering angle lies in the range from 0 degrees to 90 degrees and the magnitude of the second sputtering angle lies in the range from 90 degrees to 180 degrees.

11. The method according to claim 10, wherein the magnitude of the second sputtering angle is 180 degrees minus the magnitude of the first sputtering angle.

12. The method according to claim 9, 10 or 11, wherein the magnitude of the first sputtering angle lies in the range from 30 degrees to 90 degrees and the magnitude of the second sputtering angle lies in the range from 90 degrees to 150 degrees.

13. The method according to any of the claims 9 to 12, wherein the first coating region is contained in a first coating chamber and the second coating region is contained in a second coating chamber.

14. Use of a sputter deposition apparatus according to any of the claims 1 to 8 to perform a method according to any of the claims 9 to 13, wherein the first angle determines the first sputtering angle and wherein the second angle determines the second sputtering angle.

15. The use of a sputter deposition apparatus according to claim 14, wherein:

the first sputtering angle plus 90 degrees equals the first angle; and

the second sputtering angle plus 90 degrees equals the second angle.