WO2016032444A1

WO2016032444A1 - Vacuum deposition apparatus and method of operating thereof

Info

Publication number: WO2016032444A1
Application number: PCT/US2014/052728
Authority: WO
Inventors: John M. White; John D. BUSCH
Original assignee: Applied Materials, Inc.
Priority date: 2014-08-26
Filing date: 2014-08-26
Publication date: 2016-03-03

Abstract

A vacuum deposition apparatus is described. The vacuum deposition apparatus includes a vacuum chamber configured for material deposition within the vacuum chamber, a cathode having a target including deposition material, wherein the cathode is provided in the vacuum chamber, and at least one anode within the vacuum chamber, wherein the at least one anode includes a first structure having a conductive surface being shielded from deposits of materials coming from the target, and wherein the conductive surface is configured to collect electrons of the plasma.

Description

VACUUM DEPOSITION APPARATUS AND METHOD OF OPERATING

THEREOF

TECHNICAL FIELD

[0001] Embodiments of the present invention relate to vacuum deposition, e.g. by sputtering from a target. Embodiments of the present invention particularly relate to sputtering on large area substrates. Embodiments relate specifically to a vacuum deposition apparatus and a method of operating a vacuum deposition apparatus.

BACKGROUND

[0002] In many applications, deposition of thin layers on a substrate, e.g. on a glass substrate is desired. Conventionally, the substrates are coated in different chambers of a coating apparatus. For some applications, the substrates are 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. Usually, the process is performed in a process apparatus or process chamber where the substrate to be coated is located. 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. [0004] For example, DC sputtering can for example be conducted by biasing one or more cathodes to a DC potential and providing a voltage between the one or more cathodes and one or more anodes. The target is provided at the anode, such that material is sputtered from the target, i.e. from or at the cathode. The anode serves for collecting electrons from the plasma. Particularly for reactive sputtering processes a phenomenon referred to as "disappearing anode" may occur. This may reduce the uptime of the deposition apparatus.

[0005] Accordingly, it is beneficial to improve PVD deposition, particularly to increase the uptime of the deposition apparatus.

SUMMARY

[0006] In light of the above, a vacuum deposition apparatus and a method of operating a vacuum deposition apparatus are provided.

[0007] According to one embodiment, a vacuum deposition apparatus is provided. The vacuum deposition apparatus includes a vacuum chamber configured for material deposition within the vacuum chamber, a cathode having a target including deposition material, wherein the cathode is provided in the vacuum chamber, and at least one anode within the vacuum chamber, wherein the at least one anode includes a first structure having a conductive surface being shielded from deposits of materials coming from the target, and wherein the conductive surface is configured to collect electrons of the plasma.

[0008] According to a further embodiment, a method of operating a vacuum deposition apparatus is provided. The method includes sputtering with an anode, wherein at least 90% of the outer surface of the anode is covered with an insulating material.

[0009] Further advantages, features, aspects and details are evident from the dependent claims, the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] So that the manner in which the above recited features of the present invention can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to embodiments. The accompanying drawings relate to embodiments of the invention and are described in the following:

FIG. 1 shows a schematic view of an apparatus for deposition of material on a substrate, according to embodiments described herein;

FIG. 2 A shows cathodes and an anode between the cathodes at the beginning of operation of a deposition apparatus according to an example useful for understanding the invention;

FIG. 2B shows the cathodes and the anode of FIG. 2A after a time period of operation of the deposition apparatus according to example useful for understanding the invention;

FIG. 3 A shows cathodes and an anode between the cathodes at the beginning of operation of a deposition apparatus according to embodiments described herein;

FIG. 3B shows the cathodes and the anode of FIG. 3A after a time period of operation of the deposition apparatus according to embodiments described herein;

FIG. 4 shows a schematic view of an anode for use in a deposition apparatus according to embodiments described herein;

FIGS. 5A and 5B show different schematic cross-sectional views of an anode for use in a deposition apparatus according to embodiments described herein;

FIGS. 6A and 6B show different schematic cross-sectional views of a further anode for use in a deposition apparatus according to embodiments described herein;

FIG. 7 shows a schematic cross-sectional view of a yet further anode for use in a deposition apparatus according to embodiments described herein; FIG. 8 shows a schematic cross-sectional view of a deposition apparatus having a rotary cathode array configuration and anodes according to embodiments described herein, wherein the array is supplied by DC power supplies;

FIG. 9 shows a schematic cross-sectional view of a yet further anode for use in a deposition apparatus according to embodiments described herein;

FIG. 10 shows a schematic cross-sectional view of a yet further anode for use in a deposition apparatus according to embodiments described herein; and

FIG. 11 shows a flow chart illustrating a method for deposition of material on a substrate, according to embodiments described herein.

DETAILED DESCRIPTION OF EMBODIMENTS

[0011] Reference will now be made in detail to the various embodiments of the invention, 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. In the following, only the differences with respect to individual embodiments are described. Each example is provided by way of explanation of the invention and is not meant as a limitation of the invention. 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.

[0012] According to embodiments described herein, with exemplary reference to FIG. 1, an apparatus 100 for deposition of material on a substrate including a deposition array 222 having for example one or more cathodes is provided. The deposition array 222, as shown in FIG. 1 includes six cathodes 122 and seven anodes 115. Each of the cathodes is connected to a power supply 123. The anodes can be connected to one of the power supplies, typically the power supply of a neighboring cathode. According to yet further embodiments, which can be combined with other embodiments described herein, two or more of the cathodes and/or two of the anodes may also be connected to one power supply 123. For example, each of the cathodes can deposit material on the same substrate during the same time.

[0013] In the present disclosure, and not limited to any specific embodiment described herein, a deposition array includes a plurality of cathodes, particularly at least three deposition assemblies. The plurality cathodes may be arranged adjacent to each other. Particularly, the plurality of cathodes may be arranged parallel to each other, for example parallel with an equal spacing between neighboring deposition assemblies. However, embodiments described herein also relate to a single cathode, which can be operated in a deposition apparatus.

[0014] Sputtering can be conducted as DC (direct current) sputtering, MF (middle frequency) sputtering, as RF sputtering, or as pulse sputtering. As described herein, some deposition processes might beneficially apply MF, DC or pulsed sputtering. Embodiments described herein are particularly useful for DC sputtering, MF sputtering or pulsed sputtering, wherein the plasma is generated utilizing an anode, for example with a cathode and an anode.

[0015] According to some embodiments, which can be combined with other embodiments described herein, the sputtering according to the described embodiments can be conducted with three or more cathodes. However, particularly for applications for large area deposition, an array of cathodes having 6 or more cathodes, e.g. 10 or more cathodes, can be provided. For example, three or more cathodes or cathode pairs, e.g. four, five, six or even more cathodes or cathode pairs can be provided. The array can be provided in one vacuum chamber. Further, an array can typically be defined such that adjacent cathodes or cathode pairs influence each other, e.g. by having interacting plasma confinement. According to typical implementations, the sputtering can be conducted by a rotary cathode array, such as, but not limited to, a system such as PiVot of Applied Materials Inc.. However, embodiments are also directed to a vacuum deposition apparatuses having at least one cathode and at least one anode.

[0016] As shown in FIG. 2A, one or more cathodes 122 can be operated to sputter material from the target 202. According to typical embodiments, the target is rotated as indicated by arrow 212 during sputtering from the target. During sputtering, a plasma is generated. Electrons within the plasma are collected by anode 15. This is indicated schematically in FIG. 2A. During operation of the vacuum deposition apparatus, material from the target 202 is deposited on a substrate. Yet, material from the target 202 is partly also deposited on the anode 15, such that a layer 16 of deposition material is coated on the anode. This is shown in FIG. 2B. In the event of insulating deposits, the anode disappears, which can generate problems in many sputtering processes, for example reactive sputtering processes. The layer 16 of deposition material can be considered as a parasitic deposition on a portion of the vacuum deposition apparatus, e.g. the anode. For proper operation of the vacuum deposition apparatus, the anode needs to be cleaned or replaced after a certain amount of insulating deposits is coated on the anode.

[0017] According to embodiments described herein, an anode 115 is provided (see, for example, FIG. 3 A). For example, the anode 115 can be a hollow anode. The anode 115 can include a plurality of openings 116. Accordingly, insulating deposits are coated as shown by layer 16 of the position material in FIG. 3B except for areas in the openings of the anode 115, within the anode 115, and optionally around the openings in the anode 115. Embodiments described herein provide an anode surface to collect electrons e.g. on the inside surface of the pipe forming the anode. In light thereof, the anode according to embodiments described herein does not disappear upon having an insulating layer deposited thereon.

[0018] FIG. 4 shows a schematic view of the anode 115, wherein the cross-section shown in FIG. 3B corresponds to the indicated cross-section in FIG. 4. The anode 115 includes a pipe 415. A plurality of openings 116 are provided in the pipe 415. As shown in FIG. 4, a layer 16 deposited on the anode 115 is provided, such that an anode surface, for example the inside of the pipe 415 is suitable to collect electrons from the plasma inspired of the layer 16. The plurality of openings are provided in a lateral surface of the anode 115, e.g. a lateral surface of the pipe 415. According to some embodiments, the first pipe has a lateral surface extending from a first end surface to a second end surface, and wherein the plurality of openings are provided in the lateral surface.

[0019] According to some embodiments, which can be combined with other embodiments described herein, the pipe 415 may also be a tube or another hollow component. For example, the cross-section of the pipe or tube can be circular. However, the cross section can have any shape selected from the group consisting of: circular, oval, rectangular, square, triangular, and another polygon shape. According to some embodiments, the pipe 415 extends along a lengthwise direction, which may for example extend parallel or essentially parallel to the rotation axis of a rotatable sputter cathode. According to yet further embodiments, which can be combined with other embodiments described herein, also another structure, for example a hollow structure, can be used as an anode, wherein a shielded surface is provided as an anode surface. Accordingly, at least one anode includes a first structure having a conductive surface being shielded from deposits of materials coming from the target. The conductive surface is configured to collect electrons of the plasma. The structure can be a box, a sphere, a pipe, a tube or another component as described above. According to yet further embodiments, which can be combined with other embodiments described herein, the structure can be additionally or alternatively be provided described as an electrically conductive structure, a structure between two adjacent cathodes, a structure extending in a symmetry plane of two adjacent cathodes, and/or a structure extending in parallel between two adjacent cathodes.

[0020] According to some embodiments, which can be combined with other embodiments described herein, that size of the openings 116 is 0.5 mm or above, for example 2 mm or above. The size of the openings 116 is understood as the diameter in the event of circular openings 116. In the event of non-circular openings, the size of the openings 116 is understood as the smallest dimension of the opening.

[0021] According to yet further embodiments, which can be combined with other embodiments described herein, a plurality of openings or at least 90% of all openings in the pipe 415 can be provided to have a distance between neighboring openings of 10 mm or above, for example of 20 mm or above. According to yet further embodiments, which can be combined with other embodiments described herein, a plurality of openings or at least 90% of all openings in the pipe are provided to have a distance between neighboring openings less than about 3 times the distance between the cathode and the anode.

[0022] As schematically illustrated in FIG. 8, an anode 115 may be connected to a gas distribution system, for example a group of tanks, which may provide processing gas within a pipe of the anode 115. The processing gas may for example be argon, oxygen, or a combination thereof. [0023] In the event of a gas distribution of a processing gas within the pipe 415, the size of the openings 116 may further be 2 mm or below. A uniform processing gas distribution can be more easily provided by a plurality of small openings. However, for preventing covering the surface of the anode, i.e. including the openings, which serves to provide an anode surface in spite of the layer deposited on the anode, the openings should have a size of 0.01 mm or above, for example 0.3 mm or above. Yet, large openings may suffer from a reduced gas distribution uniformity as the gas pressure within the anode might not be sufficiently high to uniformly provide each of the openings with processing gas. In light thereof, according to some embodiments, the number of openings can be reduced by implementing openings in an anode pipe only in selected portions along the circumference of the anode. For example, the openings may only be provided where it is beneficial for the sputtering process. According to some embodiments, which can be combined with other embodiments described herein, the openings may only be provided in 70% or less of the circumference of the anode, for example only in 50% of the circumference of the anode. According to one example, which can be combined with other embodiments described herein, openings may only be provided in the half of the anode, which faces the substrate and/or the plasma.

[0024] The size of the openings 116 in the pipe 415 of the anode 115 may be 0.2 mm or above, in the event of the gas distribution system provided through the openings 116 in the anode 115. The reduced size of the openings can be provided due to the local gas density and the exit velocity of the process gas through the openings 116, which reduces material deposition in and/or around an area of the openings.

[0025] According to yet further embodiments, which can be combined with other embodiments described herein, an improved uniformity of gas distribution may also be provided with additional measures, wherein further or alternative elements such as the distribution of openings 116 in the pipe 415 are utilized for the desired gas distribution. FIGS. 5A and 5B may serve to illustrate various implementations of this improved uniformity of gas distribution. The anode shown in FIGS. 5 A and 5B includes a second pipe 515, for example a hollow second pipe. The gas distribution of processing gas is provided through the second pipe 515, via openings 516A - 516C in the second pipe 515 and via the openings 116 in the pipe 415. As shown in FIG. 5 A, the opening 516A has a larger size, for example larger diameter, as compared to the opening 516B. Further, the opening 516B has a larger size, for example larger diameter, as compared to the opening 516C. Accordingly, the uniformity of the gas distribution along the length of the anode or the desired gas distribution along the length of the anode can be adjusted by a variation in size of the openings in the second pipe 515. According to some embodiments, which can be combined with other embodiments described herein, at least one of the plurality of openings in the pipe 416 and the further plurality of openings in the pipe 515 are non- uniformly distributed along the length of the first pipe and the length of the second pipe. For example, the non-uniform distribution can be provided by varying opening sizes, varying opening distributions, varying opening patterns, varying opening density, or combinations thereof.

[0026] FIG. 5B illustrates the yet further aspect of providing a second pipe 515 within the pipe 415. As indicated by the arrows in FIG. 5B, the second pipe 515 may serve as a further anode surface, which is configured to collect electrons from the plasma. According to embodiments described herein, the openings 116 and the inside of the pipe 415 of anode 115 can be provided to be essentially free of parasitic deposition material. Accordingly, pipe 515 can be provided to be also essentially free of parasitic deposition material. Electrons entering the pipe 415 of the anode 115 through the openings 116 can be collected by the surface of the second pipe 515. According to some embodiments, the second pipe 515 is kept on the same potential as the pipe 415, for example on ground, such that the inner surface of the pipe 415 and the surface of the second pipe 515 can serve as an anode surface.

[0027] As shown in FIG. 5 A the pipe 415 and the second pipe 515 can be provided to be essentially concentric, i.e. concentric with a deviation of +- 5%. For example, spacers 522 can be provided at the inner pipe or the outer pipe, to align the two pipes with respect to each other. The two pipes or cylinders may be connected at various points by various means, e.g. by spacers 522, to ensure structural integrity and concentricity.

[0028] According to embodiments described herein, an anode, e.g. a hollow anode with openings can be provided, which allows for collection electrons on the inside surface of the hollow anode or pipe, which is protected from insulating deposits. The problem of a "disappearing anode", which creates problems in many reactive-sputtering processes, can be reduced or avoided. As described above, one or more of various measures can be taken to distribute process gases uniformly or in another predetermined manner, as desired, into the vacuum chamber, for example the sputter chamber. A careful gas distribution is often beneficial, particularly for reactive processes.

[0029] In light of the second pipe 515 having the openings 516A - 516C, which can be configured for controlling the gas distribution along the length of the anode, as shown in FIGS. 5 A and 5B, the inner tube can serve to distribute the gas as desired within the outer tube. Accordingly, the function of process gas distribution can be separated from the main function of the outer tube, namely the provision of an anode surface in spite of insulating deposits on the anode. The second pipe may also serve as an additional (protected) anode surface.

[0030] A yet further anode is shown in FIGS. 6 A and 6B. The hollow anode or pipe 615 includes an inner wall and an outer wall, wherein a conduit 605 is provided between the inner wall and the outer wall. Accordingly, a cooling fluid can be provided within the anode for cooling the anode during operation of the vacuum deposition apparatus.

[0031] According to yet further implementations, the anode can be formed by a pipe 615 and a second pipe 616, wherein gas conduits configured for gas conveyance are provided. The gas conduits provide the openings 116 in the anode. The hollow anode can be cooled to dissipate the heat energy transferred to the anode during sputtering, particularly heat radiation and energy provided by the collective electrons. The conduits can have a length, for example in a radial direction of a circular pipe shown in FIG. 6B, of 2 mm or above.

[0032] The plurality of openings 116 are configured to have a locally high pressure and flow of the process gases in the conduit. This can prevent deposits, for example insulating deposits, from forming in an area by the opening coatings. Accordingly, an anode surface, i.e. a conductive anode surface, can be maintained and the occurrence of a "disappearing anode" can be reduced or prevented. According to some embodiments, which can be combined with other embodiments described herein, an anode having a conduit 605 provided between the first pipe and a second pipe, may be a structure of brazed and/or welded pieces of tubing. According to yet further embodiments, which can be combined with other embodiments described herein, a similar structure can be provided by an extrusion with holes drilled through the walls for gas conveyance.

[0033] A yet further embodiment, which can be combined with other embodiments described herein is schematically illustrated in FIG. 7. The pipe 615 includes a conduit 605 for cooling fluid. The cooling fluid can be, for example, provided within the anode along the lengthwise direction for cooling of the anode. The openings 716 are provided in the form of nozzles. The nozzles can be configured to generate a jet of processing gas. For example, the openings can be provided as extrusion with holes drilled through the outer wall of the pipe 615. Accordingly, the openings 716 and/or the nozzles can be provided for gas conveyance with increased pressure and flow of process costs through the nozzle. This may further reduce parasitic coating of the openings, for example in the openings or near the openings. According to yet further embodiments, which can be combined with other embodiments described herein, various shapes of the nozzles along the length of the nozzle can be provided. For example, nozzles can have the largest diameter at the radially inner side of the nozzle. This can increase the gas velocity at the radially outer side of the nozzle. Alternatively, the nozzle can have the smallest diameter between the radially inner end and the radially outer end of the nozzle, e.g. in a middle section of the radial extension of the nozzle. This enables to increase the gas velocity in the nozzle, while the size of the opening at the radially outer end of the nozzle can be increased as compared to the smallest diameter in order to reduce the probability of having parasitic deposits on the opening, i.e. the nozzle.

[0034] FIG. 8 shows a view, for example a top view of the vacuum deposition apparatus 100. The vacuum deposition apparatus 100 may be utilized for dynamic deposition or static deposition, metallic sputtering processes or reactive sputtering processes. According to some embodiments, which can be combined with other embodiments described herein, static deposition of material on a substrate can be conducted by a reactive sputter process. That means that the stoichiometry of the film is obtained by sputtering either metallic, semi-metallic or compound targets using a mixture of non-reactive gas and reactive gases. Typically, embodiments described herein may also be suitable for deposition of metal layers or semiconducting layers using only non-reactive gas as processing gas. Reactive sputtering processes, for example, deposition processes during which a material is sputtered under an oxygen atmosphere or another reactive atmosphere in order to deposit a layer containing an oxide or the like of the sputtered material, need to be controlled with respect to plasma stability. The reactive deposition process can be, for example, a deposition of aluminum oxide (A1203) or silicon oxide (Si02) or Indium-Gallium-Zinc- Oxide (IGZO), wherein aluminum, silicon, indium, gallium or zinc are sputtered from a cathode while oxygen is provided in the plasma. For example, aluminum oxide, silicon oxide or Indium-Gallium-Zinc-Oxide can be deposited on a substrate. According to typical embodiments, processing gases can include non-reactive gases such as argon (Ar) and/or reactive gases such as oxygen (02), nitrogen (N2), hydrogen (H2), water (H20), ammonia (NH3), Ozone (03), activated gases or the like.

[0035] FIG. 8 shows a schematic cross-sectional view of a deposition apparatus 100 according to embodiments as described herein. Exemplarily, one vacuum chamber 102 for deposition of layers therein is shown. As indicated in FIG. 8, further chambers 102 can be provided adjacent to the chamber 102. The vacuum chamber 102 can be separated from adjacent chambers by a valve having a valve housing 104 and a valve unit 105. After the carrier 1 14 with the substrate 14 thereon is, as indicated by arrow 1, inserted in the vacuum chamber 102, the valve unit 105 can be closed. Accordingly, the atmosphere in the vacuum chambers 102 can be individually controlled by generating a technical vacuum, for example, with vacuum pumps connected to the chamber, and/or by inserting processing gases in the deposition region in the chamber 102, for example through anodes 115. As described above, for many large area processing applications, the large area substrates are supported by a carrier. However, embodiments described herein are not limited thereto and other transportation elements for transporting a substrate through a processing apparatus or processing system may be used.

[0036] Within the chamber 102, a transport system is provided in order to transport the carrier 114, having the substrate 14 thereon, into and out of the chamber 102. The term "substrate" as used herein shall embrace inflexible substrates, e.g., a glass substrate, a wafer, slices of transparent crystal such as sapphire or the like, or a glass plate. The term "substrate" as used herein shall further embrace flexible substrates, such as webs or foils, wherein sputter deposition takes place for example in a roll-to-roll vacuum deposition apparatus. [0037] As illustrated in FIG. 8, within the chamber 102, deposition sources, e.g. cathodes 122, are provided. The deposition sources can, for example, be rotatable cathodes having targets of the material to be deposited on the substrate. According to embodiments, which can be combined with other embodiments described herein, the cathodes can be rotatable cathodes with a magnet assembly 121 therein. Magnetron sputtering can be conducted for depositing of the layers. With exemplary reference to FIG. 8, according to some embodiments, the apparatus may include cathodes 122 and anodes 115, which may be electrically connected to a DC power supply.

[0038] Sputtering from a target for, e.g., a transparent conductive oxide film is typically conducted as DC sputtering. According to yet further embodiments, which can be combined with other embodiments described herein, for example, materials like ITO, IZO, IGZO or MoN, might be deposited with a DC sputter deposition process. The cathodes may be connected to the DC power supply together with the anode for collecting electrons during sputtering. According to some embodiments, which can be combined with other embodiments described herein, the processing gas can be provided on one side of the anode 115, i.e. the pipe. For example, for a vertically oriented anode, the gas can be provided to an upper side of the anode or a lower side of the anode. According to yet further implementations, the processing gas can be provided at two positions of the length direction of the anode, e.g. the upper and the lower side. Yet further, the process gas can be provided at two or more positions of the anode, in order to have the pressure within the hollow anode be provided more uniformly.

[0039] According to yet further embodiments, which can be combined with other embodiments described herein, one or more of the cathodes can each have their corresponding, individual voltage supply. For example, one power supply can be provided per cathode for at least one, some or all of the cathodes. Accordingly, at least a first cathode and anode can be connected to a first power supply, and a second cathode and anode can be connected to a second power supply.

[0040] As further illustrated in FIG. 8, within the chamber 102, mask shields 130 are also provided. As exemplarily shown in FIG. 8, the gas distribution system of apparatus 100 may include six gas tanks containing processing gas. The flow rate of non-reactive gas and/or reactive gas present in the processing gas can be controlled by mass flow controllers (MFCs). The processing gas may be fed to multiple gas inlet points through gas conduits or gas pipes 133, 233 and 333 via MFCs 134, 234 and 334, respectively. Accordingly, the embodiments of the apparatus as described herein allow for providing a different flow rate of processing gas and/or different processing gas mixture independently of the first outer deposition assembly 301, the second outer deposition assembly 302 and the inner deposition assembly 303. Accordingly, an apparatus for depositing material on a substrate is provided with which a thickness drop at the substrate edges in transport direction can substantially be avoided.

[0041] As shown in FIG. 8, embodiments described herein can be provided for a static deposition process, e.g. valve units 105 are closed during deposition, with a plurality of rotary cathodes, e.g. three or more rotary cathodes. While the deposition process is switched off, the substrate 14 is moved into the position for deposition in the deposition area. The process pressure can be stabilized. Once the process is stabilized, the cathode magnet assemblies 121 can be rotated toward the front to deposit the correct stoichiometry of the material to be deposited onto the static substrate until the end of deposition. However, embodiments including an improved anode, i.e. an anode with longer uptime as described herein, may also be used for dynamic deposition processes on flexible or even inflexible substrates.

[0042] With exemplary reference to FIG. 8, the apparatus according to embodiments as described herein, may include a controller 500, which is configured for controlling at least one process parameter of the first outer deposition assembly and the second outer deposition assembly. Further, the controller 500 may be configured for controlling at least one process parameter of the inner deposition assembly. According to embodiments as described herein, a deposition assembly (e.g. the first outer deposition assembly, the second outer deposition assembly and the inner deposition assembly) may include at least one cathode, particularly a rotary cathode, a gas distribution system or a segment of a gas distribution system, and a magnetic assembly. Therefore, according to embodiments as described herein the at least one processing parameter can be controlled by the controller 500. According to embodiments described herein, the at least one processing parameter is at least one selected from the group consisting of: a power supplied to the first outer deposition assembly and the second outer deposition assembly, an amount of processing gas supplied to the first outer deposition assembly and the second outer deposition assembly, and a magnetic field at the first outer deposition assembly and the second outer deposition assembly. Accordingly, an apparatus for deposition of material on a substrate is provided which is configured such that material can be deposited at the first outer deposition assembly 301 and/or the second outer deposition assembly (302) at a higher rate than at the inner deposition assembly 303 on the same substrate during the same time. Accordingly, an apparatus for depositing material on a substrate is provided with which a thickness drop at the substrate edges in transport direction can substantially be avoided.

[0043] As exemplarily shown in FIG. 8, the deposition process can be conducted with rotary cathodes and a rotating magnet assembly, i.e. a rotating magnet yoke therein. As used herein, "magnetron sputtering" refers to sputtering performed using a magnetron, i.e. a magnet assembly, that is, a unit capable of generating a magnetic field. Typically, such a magnet assembly consists of one or more permanent magnets. These permanent magnets are typically arranged within a rotatable target or coupled to a planar target in a manner such that the free electrons are trapped within the generated magnetic field generated below the rotatable target surface. Such a magnet assembly may also be arranged coupled to a planar cathode. According to typical implementations, magnetron sputtering can be realized by a double magnetron cathode, i.e. cathodes 122, such as, but not limited to, a TwinMagTM cathode assembly. Particularly, for MF sputtering (middle frequency sputtering) from a target, target assemblies including double cathodes can be applied. According to typical embodiments, the DC sputtering is conducted, wherein the anode serves to collect electrons. However, also other sputtering processes utilizing an anode pipe can benefit from embodiments described herein, wherein an additional anode surface is provided inside of a hollow anode. According to different embodiments, which can be combined with other embodiments described herein, sputtering can be conducted as DC sputtering, MF (middle frequency) sputtering, as RF sputtering, or as pulse sputtering. As described herein, some deposition processes might beneficially apply MF, DC or pulsed sputtering. However, other sputtering methods can also be applied.

[0044] In FIG. 8 a plurality of cathodes 122 with a magnet assembly 121 or magnetron provided in the cathodes are shown. According to some embodiments, which can be combined with other embodiments described herein, the sputtering according to the described embodiments can be conducted with three or more cathodes. However, particularly for applications for large area deposition, an array of cathodes or cathode pairs can be provided. For example, three or more cathodes or cathode pairs, e.g. three, four, five, six or even more cathodes or cathode pairs can be provided. The array can be provided in one vacuum chamber. Further, an array can typically be defined such that adjacent cathodes or cathode pairs influence each other, e.g. by having interacting plasma confinement.

[0045] Yet, according to different embodiments, which can be combined with other embodiments described herein, the plasma sources in one chamber can have varying plasma positions (rotational positions for rotary cathodes) during the deposition of the layer on the substrate. For example, the magnet assemblies or magnetrons can be moved relative to each other and/or relative to the substrate, e.g. in an oscillating or back-and-forth manner, in order to increase the uniformity of the layer to be deposited.

[0046] As shown in FIG. 8, a substrate 14 is provided on a first side of the cathodes 122 and the target provided thereon. The anodes 115 are provided between the cathodes 122 and are for example provided on a second side of the cathodes 122. For example, the center of the cathodes 122 is between the center of the anode 115 and the substrate 14. According to some embodiments, which can be combined with other embodiments described herein, the openings in the anodes 115 (not shown in FIG. 8) can be oriented to avoid direct gas flow from the anode 115 to the target surface. For example, the openings can be provided at the side of the anodes 115 opposing the side of the substrate or that substrate transport arrangement, respectively.

[0047] Even though embodiments described herein may be used for inflexible and flexible substrates, vacuum deposition apparatuses according to embodiments described herein may be beneficially utilized for display manufacturing. According to some embodiments, which can be combined with other embodiments described herein, the 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 have a plurality of substrates, may have a size of at least 0.67 m². Typically, the size can be about 0.67m2 (0.73x0.92m - Gen 4.5) to about 8 m², more typically about 2 m² to about 9 m² or even up to 12 m². Typically, the substrates or carriers, for which the structures, apparatuses, such as cathode assemblies, and methods according to embodiments described herein are provided, are 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. According to some embodiments, which can be combined with other embodiments described herein, the substrates and/or the carriers described herein and the apparatuses for utilizing the gas distribution systems described herein, can be configured for vertical substrate processing. The term vertical substrate processing is understood to distinguish over horizontal substrate processing. That is, vertical substrate processing relates to an essentially vertical orientation of the carrier and the substrate during substrate processing, wherein a deviation of a few degrees, e.g. up to 10° or even up to 15°, from an exact vertical orientation is still considered as vertical substrate processing. A vertical substrate orientation with a small inclination can, for example, result in a more stable substrate handling or reduced risk of particles contaminating a deposited layer. Alternatively, the gas distribution systems according to embodiments described herein may also be utilized for substrate orientations other than essentially vertical, e.g. a horizontal substrate orientation. For a horizontal substrate orientation the cathode array and the anodes would, for example, also be essentially horizontal.

[0048] According to yet further embodiments, which can be combined with other embodiments described herein, the target material can be selected from the group consisting of: aluminum, silicon, tantalum, molybdenum, niobium, titanium, indium, gallium, zinc, tin, silver and copper. Particularly, the target material can be selected from the group consisting of indium, gallium and zinc. The reactive sputter processes provide typically deposited oxides of these target materials. However, nitrides or oxi-nitrides might be deposited as well. [0049] FIG. 9 shows another embodiment of the anode 115 according to embodiments described herein. The anode has the first pipe 415. Openings 116 are provided in in the first pipe. A second pipe 915 is provided within the first pipe 415, for example concentrically within the first pipe. Spacers 522 can be provided for structural integrity and/or concentricity. According to embodiments, which are explained with respect to FIG. 9, the second pipe 915 can provide a further anode surface. Electrons, which enter the anode 115 through an opening 116 can be collected by the second pipe 915. According to some embodiments, the second pipe 915 is electrically connected to the first pipe 415. The further pipe is, thus, provided on the same potential as the first pipe 415 of the anode, for example on ground potential.

[0050] The distribution of processing gas can be provided between the first pipe 415 and the second pipe 915, e.g. between two concentric pipes. The outer pipe, i.e. the first pipe 415, collects the deposits. The openings 116 provided in the first pipe 415 can be uniformly distributed along the lines of the first pipe 415. The openings 116 may as well be non-uniformly distributed along the lines of the first pipe 415. The openings 116 can be arranged for uniform distribution of processing gas in the process chamber and/or for the distribution of the processing gas in the process chamber, which results in uniform deposition rates of the sputter cathodes.

[0051] The second pipe 915, which may be hollow or solid, can provide structural integrity and is shielded from heat radiation curing the position and from deposits collected by the outer pipe 415. The two pipes can be connected at various points or positions, for example to ensure structural integrity and concentricity. Process gases can be distributed uniformly or in another predetermined manner, as desired into the sputter chamber, i.e. the vacuum chamber. According to some embodiments, processing gas can enter between the first pipe 415 and the second pipe 915. Yet further, alternatively or additionally the further pipe can serve as an additional anode surface, which can, for example, be protected by the first pipe 415.

[0052] Embodiments described herein refer to various aspects of an anode, for example, for a sputtering process, wherein disadvantages of parasitic insulating coatings that may result in the disappearing anode can be reduced or overcome. Openings are provided in a pipe. Accordingly, electrons can enter the pipe and use an inner surface of the pipe or a surface provided within the pipe as an anode surface. One option is to make the openings small enough such that the sum of the opening areas of all openings is in the same order of magnitude as the area of the pipe cross-section. This improves gas distribution of processing gases, which may additionally be provided through the openings. Further, an increased velocity of the processing gas entering a vacuum chamber through the openings may additionally reduce parasitic deposition of insulating materials in and around the openings. According to a further additional or alternative option, the number of openings can be reduced by providing openings only in a portion of the circumference of the pipe. The reduced number of openings allows for larger openings while maintaining the sum of the opening areas of all openings in the same order of magnitude. Yet further additionally or alternatively an inner pipe can be provided as a gas supply, wherein openings in the inner pipe can be configured for a uniform gas pressure along the length of the anode or another desired gas pressure distribution along the length of the anode. Accordingly, openings in the inner pipe can be positioned to improve the gas distribution and openings in the outer pipe can be positioned to improve collection efficiency of electrons from the plasma and/or the potential distribution provided by the anode for electrons in the plasma. Yet further additionally or alternatively, several gas inlets into the anode can be provided for more uniform distribution of processing gas through the anode. According to some embodiments, which can be combined with other embodiments described herein one or more of the above options, for example all of the above options, can be implemented.

[0053] According to yet further embodiments, which can be combined with other embodiments described herein, the openings in the first pipe, for example the outer pipe of an anode, can be provided to influence the plasma density in the vacuum chamber. For example, the number of openings along the length of the anode can be higher in the center portion of the anode as compared to an outer portion or the two opposing outer portions of the anode. Accordingly, the anode surface provided at outer portions of the anode is reduced as compared to the center of the anode along the lengthwise direction. This can be used to influence the plasma density within the vacuum chamber. The opening distribution in the anode can, thus, additionally or alternatively to an opening distribution considering the distribution of the processing gas, also be configured to influence the available anode surface of an anode coated with parasitic insulating deposits. This may improve precision uniformity of the sputtering process by influencing the plasma density along the length of an anode or cathode, respectively.

[0054] FIG. 10 shows a further embodiment, wherein an anode 115 is provided next to the cathodes 122. For example, the anode 115 can be provided between two cathodes 122. Magnet assemblies 121 are provided within the cathodes. The magnet assembly can be used to confine the plasma 101 as shown in FIG. 10. The anode 115 can have a conduit 605 four cooling fluid within the anode. A further pipe 935 can be provided as a shield, wherein the further pipe has a slit. The slit is provided at a side of the further pipe 935, which is opposing the plasma 101, a substrate support and/or the substrate. According to some embodiments, which can be combined with other embodiments described herein, the slit has the maximum size such that at least 50% of the first pipe, i.e. the anode 115, is shielded by the further pipe.

[0055] As schematically illustrated in FIG. 10, a layer 16, for example a layer of parasitic insulating deposits, is provided on the further pipe 935. Further, a layer 16 may also be provided on one side of the first pipe forming the anode. A gap is provided between the first pipe and the further pipe, such that the electrons can be collected by the shielded portion of the first pipe and/or an inner surface of the further pipe, i.e. the shield. According to some embodiments, which can be combined with other embodiments described herein, the further pipe 935, which can act as a shield, can be electrically connected to the first pipe of the anode 115. Accordingly, in a condition without insulating deposits, a further pipe 935 and the first pipe of the anode 115 can provide an outer anode surface.

[0056] As described herein, embodiments including an anode, which is capable of providing additional anode surface is in spite of insulating deposits, i.e. parasitic deposits, on the outer surface of the anode and/or a shield, can increase the uptime of the vacuum deposition apparatus. Due to the additional anode surface, sputter deposition can be conducted in spite of insulating deposits. The disadvantage of a "disappearing anode" can be reduced or avoided. FIG. 11 illustrates a flow chart 900 of a method of operating the vacuum deposition apparatus according to embodiments described herein. As indicated in box 901, sputtering can be conducted with an anode having at least 90%> of the outer surface of an anode and/or shields surrounding the anode are covered with an insulating material. Optionally, a processing gas can be provided in the vacuum chamber through a plurality of openings in the anode (see box 902).

[0057] Embodiments described herein can be particularly beneficial for DC- or MF- sputtering reactive processes, in which insulating layers are deposits from conductive targets, which may show a "disappearing anode". According to some embodiments, which can be combined with other embodiments described herein, a processing gas, for example argon and/or oxygen, can further be utilized to prevent or reduce deposits from forming on the entire anode surface by using the momentum of the gas molecules of processing gas. Sputter material can be prevented from landing on at least some areas of the anode surface, for example the inside surface of the pipe of the anode as well as some areas outside surrounding the openings, i.e. the gas holes, this means that the local density and altered flow of the processing gas exiting the openings in the pipe of the anode can keep the incoming sputtered material from landing and depositing on respective areas of the anode. Additionally or alternatively, an anode surface can be shielded irrespective of the flow of processing gas, for example by providing a further pipe around a pipe of the anode having a slit. Yet further, optional implementations may include a pipe inside the anode pipe, which may provide an additional anode surface, which can also be shielded by the anode pipe surrounding the inner pipe.

[0058] While the foregoing is directed to embodiments of the invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.

Claims

1. A vacuum deposition apparatus, comprising: a vacuum chamber configured for material deposition within the vacuum chamber; a cathode having a target including deposition material, wherein the cathode is provided in the vacuum chamber; at least one anode within the vacuum chamber, wherein the at least one anode includes a first structure having a conductive surface being shielded from deposits of materials coming from the target, and wherein the conductive surface is configured to collect electrons of a plasma.

2. The vacuum deposition apparatus according to claim 1, wherein the first structure is a first pipe.

3. The vacuum deposition apparatus according to claim 2, wherein the first pipe has a plurality of openings, wherein the conductive surface is an inside surface of the anode, and wherein the plurality of openings are configured to expose the inside surface to the electrons of the plasma.

4. The vacuum deposition apparatus according to claim 3, wherein the first pipe has a lateral surface extending from a first end surface to a second end surface, and wherein the plurality of openings are provided in the lateral surface.

5. The vacuum deposition apparatus according to any of claims 3 to 4, wherein one or more openings of the plurality of openings have a size of 0.01 mm or above.

6. The vacuum deposition apparatus according to any of claims 3 to 5, wherein at least 90% of all openings in the pipe are provided to have a distance between neighboring openings of less than about 3 times the distance between the cathode and the anode.

7. The vacuum deposition apparatus according to any of claims 2 to 6, wherein the first pipe is not connected to a gas supply.

8. The vacuum deposition apparatus according to claim 1, further comprising: a further structure provided in the first structure or around the first structure.

9. The vacuum deposition apparatus according to any of claims 2 to 8, further comprising a second pipe.

10. The vacuum deposition apparatus according to claim 9, wherein the second pipe provides an additional anode surface.

11. The vacuum deposition apparatus according to any of claims 9 to 10, wherein the second pipe has a further plurality of openings provided in the second pipe or wherein the second pipe has a slit provided in the second pipe, particularly wherein the second pipe is provided around the first pipe and the slit has a maximum size such that at least 10 % of the first pipe is shielded by the second pipe.

12. The vacuum deposition apparatus according to claim 11, wherein the second pipe is provided in the first pipe and wherein the second pipe is connected to a gas supply for providing one or more process gases to the second pipe, wherein the second pipe is in fluid communication with the vacuum chamber via the further plurality of openings in the second pipe and via the plurality of openings in the first pipe.

13. The vacuum deposition apparatus according to any of claims 11 to 12, wherein at least one of the plurality of openings and the further plurality of openings are non- uniformly distributed along the length of the first pipe and the length of the second pipe.

14. The vacuum deposition apparatus according to any of claims 4 to 13, further comprising: one or more cooling channels, which are provided in the wall of the lateral surface.

15. A method of operating a vacuum deposition apparatus, comprising: sputtering with an anode, wherein at least 90% of the outer surface of the anode is covered with an insulating material.

16. The method according to claim 15, wherein the vacuum deposition apparatus is a vapor deposition apparatus according to any of claims 1 to 14.

17. The method according to any of claims 15 to 16, further comprising: providing a processing gas in a vacuum chamber through a plurality of openings in the anode, where the anode comprises an axially-oriented open cavity for conveying the processing gas.