WO2015090373A1

WO2015090373A1 - Electrode assembly for deposition apparatus and method for assembling said electrode assembly

Info

Publication number: WO2015090373A1
Application number: PCT/EP2013/076984
Authority: WO
Inventors: Anke Hellmich; Frank Schnappenberger; Andreas Lopp; Thomas Gebele
Original assignee: Applied Materials, Inc.
Priority date: 2013-12-17
Filing date: 2013-12-17
Publication date: 2015-06-25
Also published as: CN105900209A; KR20160104639A; CN105900209B; TW201538768A; KR102174178B1

Abstract

An electrode assembly (120; 200; 300; 400; 700; 800; 900) for a sputter deposition apparatus is provided. The electrode assembly includes an assembly element (210; 310; 410; 710; 810; 910) for at least one of providing material to be deposited and holding a rotatable target; a magnet system (230; 330; 430; 730; 830; 930) disposed inside the assembly element (210; 310; 410; 710; 810; 910); and a pole piece (240; 241; 242; 340; 341; 342; 440; 441; 442; 740; 741; 742; 840; 841; 842; 940; 941; 942) for being disposed between the magnet system and the assembly element. Further, a method for assembling an electrode assembly with a magnet system (230; 330; 430; 730; 830; 930) is described.

Description

ELECTRODE ASSEMBLY FOR DEPOSITION APPARATUS AND METHOD FOR ASSEMBLING SAID ELECTRODE ASSEMBLY

TECHNICAL FIELD OF THE INVENTION

[0001] Embodiments of the present invention relate to an electrode assembly for a deposition apparatus, and a method for assembling an electrode assembly for a deposition apparatus. Embodiments of the present invention particularly relate to an electrode assembly for a sputter deposition apparatus and a method for assembling an electrode assembly for a sputter deposition apparatus, specifically to an electrode assembly providing a magnet system in a sputter deposition apparatus.

BACKGROUND OF THE INVENTION

[0002] 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, a plasma enhanced chemical vapor deposition (PECVD) process, etc. Typically, 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. In the exemplary case that a PVD process is used, the deposition material is 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. A PVD process is for instance suitable for thin film coatings.

[0003] In a PVD process, the target is used to serve as an electrode. A process gas is filled in the process chamber at a low pressure (for instance at about 5*10^" mbar). When voltage is applied to the target and the substrate, electrons are accelerated to the anode, whereby ions of the process gas are generated by the collision of the electron with the gas atoms. By impingement of the ion, atoms of target material are ejected from the target. [0004] Coated materials may be used in several applications and in several technical fields. For instance, an application lies in the field of microelectronics, such as generating semiconductor devices. Also, substrates for displays are often coated by a PVD process. Further applications include insulating panels, organic light emitting diode (OLED) panels, substrates with TFT, color filters or the like. Further, also manufacturing of motherboards and packaging of semiconductors utilizes thin-film deposition, and particularly deposition of various metal layers.

[0005] Target electrodes are known which use a magnetic field in order to increase the efficiency of the above described process. By applying a magnetic field, electrons spend more time near the target, and more ions are generated near the target. In known cathode assemblies, one or more magnet yokes or magnet bars are arranged in order to increase the ion generation and, thus, the deposition process. However, an increasing field strength is desired in order to ameliorate the operation of the sputter apparatus. On the other side, small magnets are beneficial with regard to a cost efficient deposition apparatus.

[0006] In view of the above, it is an object of the present invention to provide an electrode assembly for a sputter deposition apparatus and a method for assembling an electrode assembly for a sputter deposition apparatus that overcomes at least some of the problems in the art.

SUMMARY OF THE INVENTION

[0007] In light of the above, an electrode assembly for a sputter deposition apparatus and a method for assembling an electrode assembly according to the independent claims are provided. Further aspects, advantages, and features of the present invention are apparent from the dependent claims, the description, and the accompanying drawings. [0008] According to one embodiment, an electrode assembly for a sputter deposition apparatus is provided. The electrode assembly includes an assembly element for at least one of providing material to be deposited and holding a rotatable target, a magnet system disposed inside the assembly element; and a pole piece for being disposed between the magnet system and the assembly element. [0009] According to another embodiment, a method for assembling an electrode assembly with a magnet system is provided. The electrode assembly includes an assembly element for at least one of providing a cylindrical target and holding a rotatable target. The method includes positioning a magnet system within the assembly element; and mounting a pole piece between the assembly element and the magnet system.

[0010] Embodiments are also directed at apparatuses for carrying out the disclosed methods and include apparatus parts for performing each described method step. These method steps may be performed by way of hardware components, a computer programmed by appropriate software, by any combination of the two or in any other manner. Furthermore, embodiments according to the invention are also directed at methods by which the described apparatus operates. It includes method steps for carrying out every function of the apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] 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 a deposition chamber, in which an electrode assembly according to embodiments described herein may be used;

Fig. 2 shows a schematic view of an electrode assembly according to embodiments described herein;

Fig. 3 shows a schematic view of an electrode assembly according to embodiments described herein; Fig. 4 shows a schematic view of an electrode assembly according to embodiments described herein;

Fig. 5 shows a schematic view of an electrode assembly according to embodiments described herein; Fig. 6a shows a schematic view of an electrode assembly according to embodiments described herein;

Fig. 6b shows a partial, detailed view of the electrode assembly shown in Fig. 6a according to embodiments described herein; Fig. 6c shows a partial, detailed view of the electrode assembly shown in Fig. 6a according to embodiments described herein;

Fig. 6d shows a partial, detailed view of the electrode assembly shown in Fig. 6a according to embodiments described herein;

Fig. 6e shows a partial, detailed view of the electrode assembly shown in Fig. 6a according to embodiments described herein;

Fig. 7 shows a schematic view of an electrode assembly according to embodiments described herein;

Fig. 8a shows a sectional view of a magnet system used in an electrode assembly according to embodiments described herein;

Fig. 8b shows a top view of the magnet system shown in Fig. 8a;

Fig. 9a shows a sectional view of a magnet system used in an electrode assembly according to embodiments described herein; Fig. 9b shows a top view of the magnet system shown in Fig. 9a;

Fig. 10 shows a flow chart of a method for assembling an electrode assembly according to embodiments described herein; and

Fig. 11 shows a flow chart of a method for assembling an electrode assembly according to embodiments described herein. DETAILED DESCRIPTION OF EMBODIMENTS

[0012] 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. Generally, 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. [0013] Fig. 1 shows a deposition chamber suitable for a sputter deposition process according to embodiments described herein. Typically, chamber 100 includes a substrate support 105, which is adapted for carrying a substrate 110. Although the substrate 110 is shown as being placed on a substrate support 105, the deposition chamber as referred to herein may also be adapted for depositing materials on a continuous substrate, such as a web, a flexible substrate or the like. The chamber may be adapted for guiding a continuous or flexible substrate through the chamber. Further, chamber 100 includes an electrode assembly 120 for providing an electrode for the sputter deposition process.

[0014] In known deposition chambers, the electrode assembly may include a magnet system, such as magnetrons, for improving the deposition process efficiency. An electrode assembly having a magnet system is usually denoted as a magnetron electrode assembly. Especially, rotary magnetrons assemblies for sputter processes have a magnet setup for plasma confinement. Due to the higher amount of process gas ions near the target when using a magnet system in the electrode assembly, higher deposition rates are possible with electrode assemblies including one or more magnet systems. Further, magnet systems in the electrode of - for instance - a PVD deposition process chamber, allow for using a lower voltage difference between cathode and anode than electrode assemblies without a magnet system. Using magnet systems in an electrode assembly increases therefore the production efficiency and improves the production speed.

[0015] However, increasing the magnetic field strength in the plasma outside the target leads to even higher process efficiency and higher deposition rates, which is beneficial regarding the production costs of products produced by sputter deposition. Therefore, stronger magnets may be used in order to increase the magnetic field strength. On the other hand, stronger magnets come with high costs, which in turn counteract the reduced production costs due to higher deposition rates when using stronger magnets.

[0016] According to embodiments described herein, an electrode assembly is providedwhich allows for increasing the magnetic field strength while saving costs or which allows for reducing the costs of sputter deposition using the same magnetic field strength. The electrode assembly according to embodiments described herein may include an assembly element for providing material to be deposited and/or holding a rotatable target. The electrode assembly further includes a magnet system inside the assembly element and a pole piece adapted for being positioned between the magnet system and the assembly element.

[0017] The assembly element may be understood as being an element of the electrode assembly. According to some embodiments, which may be combined with other embodiments described herein, the assembly element may be a target holding structure, which is adapted for holding a target during the deposition process or a backing tube of a target. In some embodiments, the target holding structure may be adapted for holding a rotatable target. According to some embodiments, the assembly element may be a cathode body, such as a substantially cylindrical cathode body, which is in particular adapted for holding or providing a target. The cathode body may include target material, the target, a backing tube of a target, devices for holding the target material or the backing tube of the target or the like. The electrode assembly according to embodiments described herein may also include a magnet system disposed inside the assembly element and a pole piece for being disposed between the magnet system and the assembly element.

[0018] A "cathode body" as described herein may be understood as a body that is adapted for acting as a cathode in a sputter deposition process. For instance, the material of the cathode body may be chosen so as to be able to use the body as a cathode. According to some embodiments, the cathode body may be adapted to be used as a cathode by providing electrical connections, or connection possibilities.

[0019] According to some embodiments described herein, the assembly element may be adapted for providing material to be deposited by including or being a target, a backing tube of a target, a cathode body including target material and the like. In some embodiments, the assembly element is adapted for holding a rotatable target by providing a holding structure for a target, a holding structure for a backing tube of a target, a holding structure for a cathode body, and the like.

[0020] The electrode assembly as described herein should be understood as being a cathode assembly, or a changing cathode-anode assembly. According to some embodiments, the term electrode assembly used herein may denote an assembly which is adapted and suitable (e.g. by choosing a proper material and geometry) for being used as a cathode in a deposition process, such as a sputter deposition process. The electrode assembly may be adapted to be mounted in a deposition chamber and may include respective connections. The electrode assembly as described herein may include connections to a power supply, such as an electrical power supply, or may include connection elements allowing the electrode assembly for being connected to a power supply.

[0021] The pole piece in the assembly element according to embodiments described herein will increase the field strength outside the assembly element, especially outside the target, in the plasma or allow the use of smaller and cheaper magnets. Further, using pole pieces between the magnet system and the assembly element may increase the plasma confinement and helps to specify the magnet system to the respective application.

[0022] Fig. 2 shows an embodiment of an electrode assembly as described herein. The electrode assembly 200 includes an assembly element 210, which may be a cathode body including the target material to be deposited on substrate 280 or a target holding element, which is adapted for holding a target. For instance, in case the assembly element 210 is a target holding element, the assembly element 210 may be a backing tube for a target or a holding device for a backing tube, a structure element adapted for fixing a target thereto or the like.

[0023] According to some embodiments, the electrode assembly 200 includes a magnet system 230. The magnet system 230 may include a first end and a second end, such as magnet poles of adverse polarity, e.g. magnet poles 235 and 236. The magnet system, which may be used in the electrode assembly as described herein, is described in detail below with respect to Figs. 8a to 9b. In some embodiments, the magnet poles of the magnet system may have a first side facing the inner side 211 of the assembly element 210, such as first side 237 exemplarily indicated for the magnet pole 236 in Fig. 2. The magnet poles of the magnet system may be arranged on a magnet yoke of the magnet system 230, especially the magnet poles of the magnet system may have a second side facing the magnet yoke, or being arranged on the magnet yoke. According to some embodiments, the magnet yoke is directed in a direction towards the axis 220 (e.g. the longitudinal axis) of the assembly element 210 compared to the magnet poles of the magnet system pointing to the inner side 211 of the assembly element. [0024] As can be seen in Fig. 2, pole pieces 240, 241, 242 are provided between the inner side 211 of the assembly element 210 and the magnet system 230, particularly between the inner side 211 of the assembly element 210 and the magnet poles 235 and 236, more particularly between the inner side 211 of the assembly element 210 and the first side of the magnet poles 235 and 236. According to some embodiments, the pole piece is provided in the gap between the first side of the magnet poles of the magnet system and the inner side of the assembly element, such as gap 271 shown in the detailed section 290 in Fig. 2. In one embodiment, the pole piece is arranged in a region where the distance between the magnet system and the assembly element is the shortest. According to some embodiments, which may be combined with other embodiments described herein, the gap between the inner side of the assembly element and the first side of the magnet pole of the magnet system may have a length of typically less than about 30 mm, more typically less than about 20 mm, and even more typically less than 15 mm. In one embodiments, the gap between the inner side of the assembly element and the first side of the magnet pole of the magnet system may have a length of typically between about 0,2 mm and about 30 mm, more typically between about 0,5 mm and about 20 mm, and even more typically between about 0,5 mm and about 15 mm. In one embodiment, the gap between the inner side of the assembly and the first side of the magnet pole of the magnet system may have a length of typically between 0,5 mm and about 5 mm. The length of the gap may be the distance 271 as shown in the detailed section 290 of Fig. 2. It should be understood that the values of the gap length, such as gap length 271 in Fig. 2, may depend on the position of the respective magnet pole in the magnet system. For instance, the magnet pole 236 of the magnet system 230 being arranged approximately as a middle magnet pole may provide a different gap between the first side and the inner side of the assembly than magnet pole 235 being arranged as an outer magnet pole in the magnet system. It should be further understood, that (depending on the design of the magnet system), the size of the gap between the first side of one magnet pole of the magnet system and the inner side of the assembly element may vary along the gap width, as can exemplarily be seen in Fig. 4. [0025] The pole piece provided between the magnet system and the assembly element may be understood as being a structure composed of material having a magnetic permeability, such as iron or the like. In some embodiments, the pole pieces may be made of a magnetically soft material, such as mild steel or constructional steel. According to some embodiments, the pole piece as described herein may serve to direct the magnetic field produced by the magnet system. In some embodiments, the pole piece is attached to the magnet system, in particular to extend a magnet pole. The pole piece may be attached, and especially fixed, to the magnet system by the magnetic forces originating from the magnetic character of the magnet system and the pole piece, or may be attached with the aid of an adhesive or the like. Generally, the pole piece described in embodiments described herein may provide a first side facing the inner side of the assembly element, such as inner side 211 of the assembly element 210 in Fig. 2, and a second side facing the magnet system, such as magnet system 230 in Fig. 2.

[0026] According to some embodiments, the pole piece as described herein may provide a shape, which is adapted to the shape of the inner side of the assembly element. Especially, the shape of the first side of the pole piece may be adapted to the shape of the inner side of the assembly element, such as inner side 211 in Fig. 2. In some embodiments, the shape of the pole piece (in particular the shape of the first side of the pole piece) corresponds to the shape of the inner side of the assembly element.

[0027] A shape of a component being described as adapted to the shape of another component may be understood as being formed in a way that allows the two components to be in relation to one another. For instance, the shape of a pole piece being adapted to the shape of an assembly element may have a relation to the shape of the assembly element by corresponding in shape, by matching the shape or by complementing the shape of the assembly element. According to some embodiments, the shape of the pole piece may fit to the shape of the assembly element. For instance, the shape of the pole piece may have a complementing shape to the shape of the assembly element. In one example, the shape of the assembly element is substantially cylindrical, in particular at the inner side, and the pole piece may have a shape having substantially the same curvature with a different radius or even with substantially the same radius. In another example, the shape of the pole piece may be adapted to the shape of the assembly element without providing a curved surface, but by having an inclined surface, which approximately fits to the shape of the assembly element, such as approximately fitting to the curvature of the assembly element, or to a polygonal shape of the assembly element. It should be understood that the pole piece having a shape fitting, matching, corresponding, being adapted, or standing in relationship to the shape of the assembly element, does not necessarily have to be in contact with the assembly element. According to some embodiments, the pole piece being located between the magnet system and the assembly element, and especially the pole piece being adapted to the shape of the assembly element, may be in contact with the assembly element, as will be explained in detail below.

[0028] The term "approximately" used herein for denoting a characteristic should be understood as describing the respective characteristic as being roughly, nearly, about, or almost the respective characteristic. For instance, a first component having a shape corresponding approximately to the shape of a second component may have a shape deviating to a certain extent from the corresponding shape. In one example, the shape of a polygon approximately corresponds to the shape of a circle. According to some embodiments, the shape of a pole piece approximately corresponding, fitting, matching, or standing in relationship to a second shape should be understood as not necessarily corresponding exactly, reproducing or mirroring the second shape.

[0029] The term "substantially" as used herein may mean that there may be a certain deviation from the characteristic denoted with "substantially." For instance, the term "substantially cylindrical" refers to a shape which may have certain deviations from the exact cylindrical shape, such as a deviation of about 1 to 10% of the general extension in one direction.

[0030] According to some embodiments, the term "cylindrical" should be understood as referring to a geometrical shape having a surface formed by points at a fixed distance from a given line segment, the axis of the cylinder. A cylindrical body or cylinder may be defined by a surface shell and by two planes being substantially perpendicular to the axis. It should be understood that a cylinder as described herein is not limited to a circular cylinder having a circular base, but may also refer to a cylinder having any suitable base shape, such as a polygon, an ellipse, or the like. Also, a cylindrical shape as described herein may refer to an approximate cylinder shape, such as a cylinder having a substantially circular base. [0031] According to some embodiments, the assembly element may have a substantially cylindrical shape. In some embodiments, the inner side of the assembly element, such as the inner side 211 of the assembly element 210 in Fig. 2, may have a substantially cylindrical shape. It is known to use rectangular magnets inside a rotating sputter target tube to provide a magnetic field at the outside of the tube. However, the rectangular shape does not fit well to the cylindrical tube such that there will always be a gap between the magnet and the tube. According to embodiments described herein, the shape of the pole piece at the side facing the inner side of the assembly element may for instance be a cylinder segment, such as a cylinder segment of a cylinder surface having a similar curvature as the inner side of the assembly element. For instance, the curvature may be similar by having substantially the same value but another sign. In one example, the shape of the pole piece at the side facing the inner side of the assembly element may be an inclined plane, whose inclination is adapted to the shape or curvature of the inner side of the assembly element.

[0032] As can be seen in Fig. 2, the pole pieces 240, 241, and 242 substantially fill a gap between the magnet system 230 and the inner side 211 of the assembly element 210. In one embodiment, the pole pieces may fill the gap completely so as to be in contact with the assembly element. In the case that the pole piece extends to the assembly element until it is in contact with the assembly element, lubrication may be provided for avoiding abrasion in a rotating arrangement. For instance, a lubrication means, such as Teflon, may be used to coat the inner side of the assembly element, the pole piece or both in order to prevent abrasion of the assembly element and/or the pole piece in a rotating arrangement. A rotating arrangement may include a rotating target, a rotating cathode body, a rotating magnet system, a combination thereof or the like.

[0033] According to an embodiment of an electrode assembly described herein, the pole piece may not extend until it contacts the assembly element, but may provide a distance between the pole piece and the assembly element. In the case that there is a distance between the pole piece and the inner side of the assembly electrode, the pole piece may fill the gap between the magnet system and the assembly element at least partially. Section 290 as indicated in Fig. 2 shows the distance 270 between the pole piece 242 and the inner side of the assembly element 210 in an enlarged view. The distance 270 between the pole piece and the assembly element may typically be between about 0,01 mm and about 1,3 mm, more typically between about 0,01 mm and about 1 mm, and even more typically between about 0,1 mm and about 1mm. In one embodiment, the distance between the pole piece and the assembly element may typically be less than 1,3 mm, more typically less than 1,0 mm, and even more typically less than 0,5 mm. According to some embodiments, the distance is chosen as small as possible, because the effect of the pole piece is the better, the smaller the distance between the pole piece and the assembly element is.

[0034] Fig. 3 shows an embodiment of an electrode assembly 300 including an assembly element 310. In the embodiment shown in Fig. 3, the assembly element 310 includes an encapsulation element 312. The encapsulation element 312 may encompass the magnet system 330 and the pole pieces 340, 341, and 342. The pole pieces 340, 341, and 342 may be adapted to the shape, or correspond to the shape of the inner side 311 of the encapsulation element 312. For instance, the shape of the pole pieces may correspond to the shape of the inner side of the encapsulation as explained above with respect to the shape of the inner side of the assembly element. According to some embodiments, the inner side of the assembly element may be provided by the inner side of the encapsulation element.

[0035] The encapsulation element may have a substantially cylindrical shape, such as a cylindrical shape having a circular base shape, a polygonal base shape, or any shape suitable shape.

[0036] In some embodiments, the pole pieces may be in contact with the inner side of the encapsulation element. In one example, a lubrication means is provided on the inner side of the encapsulation element, the side of the pole pieces facing the inner side of the encapsulation element, or both in order to avoid friction in the case that one or both of the assembly element and the pole pieces are arranged in a rotatable manner. However, according to other embodiments, the pole pieces may be provided so that they have a defined distance to the encapsulation element.

[0037] According to some embodiments, which may be combined with other embodiments described herein, the encapsulation element may be adapted for keeping a fluid in the assembly element. For instance, the encapsulation 312 element may be adapted for holding a cooling fluid in space 313 of the assembly element. According to some embodiments, the assembly element is a water cooled target tube. In a water cooled target tube, the pole piece(s) may be protected against corrosion by a housing, such as the encapsulation element. As will be explained in detail below, the pole piece may be used inside and outside the encapsulation element, and also in the cooling water to guide the magnetic field and to enhance the efficiency of the magnets. [0038] In some embodiments, the assembly element may include a backing tube for a target and the assembly element is adapted for holding a fluid between the backing tube and the encapsulation element. Although not shown, the electrode assembly may include a fluid system for supplying, exchanging, removing, or moving a fluid within the assembly element. [0039] The space of the assembly element, such as space 313 shown in Fig. 3, may be described as a space between an encapsulation element of the assembly element and a target providing element 314 of the assembly element. For instance, the target providing element may be a target material, a holding structure for a target, a holding structure for a target material (such as a backing tube), a cathode body or the like.

[0040] Fig. 4 shows an electrode assembly according to embodiments described herein. The electrode assembly 400 includes an assembly element 410. According to some embodiments, which may be combined with other embodiments described herein, the assembly element 410 in the embodiment shown in Fig. 4 may be substantially made of target material. For instance the target material may include or be the material to be deposited on the substrate. According to some embodiments, the assembly element may substantially only be made of the target material. Fig. 4 also shows further components of the electrode assembly, such as a magnet system 430 and pole pieces 440, 441, and 442 between the magnet system 430 and the assembly element 410.

[0041] In some embodiments described herein, a pole piece being arranged between a magnet system and an assembly element may be understood as a pole piece being arranged between a magnet pole of the magnet system and the assembly element. According to some embodiments, the pole piece may be provided between the assembly element and a first end of a magnet pole pointing in the direction to the assembly element, while a second end of the magnet pole points to, or is fixed to a magnet yoke. A magnet system, which may be used in embodiments described herein, is exemplarily described with respect to Figs. 8a to 9b.

[0042] The embodiment shown in Fig. 4 refers to a straight arrangement of the magnet poles 435 and 436 with respect to the magnet yoke 431. The magnet poles 435 and 436 in Fig. 4 are exemplarily shown as being substantially parallel to each other. However, it should be understood that the arrangement of the magnet poles to each other is not limiting and may be designed as exemplarily shown in Figs. 2 and 3, i.e. in an arrangement, where the magnet poles are not parallel to each other. [0043] According to some embodiments, the magnet poles of the magnet system described herein may extend substantially perpendicular to a magnet yoke being part of the magnet system. For instance, the magnet poles 435 and 436 extend substantially perpendicular from the magnet yoke 431 of magnet system 430. In a further example (e.g. shown in Fig. 3), the magnet system 330 includes a bent magnet yoke 331 from which the magnet poles 335 and 336 extend substantially perpendicular at the respective position of the magnet poles.

[0044] Fig. 5 shows an embodiment of an electrode assembly 700. The electrode assembly 700 includes an assembly element 710, which may for instance be - as described above - substantially made of the target material. The embodiment of electrode assembly 700 includes an encapsulation element 712. The encapsulation element may provide the inner side 711 of the assembly element 710. The encapsulation element 712 may have a function as discussed with respect to the encapsulation element shown in Fig. 3, and may in particular be adapted for allowing the assembly element 710 to hold a fluid within the space 713 in the assembly element, such as a cooling fluid. As can be seen in Fig. 5, the pole pieces 740, 741, and 742 arranged between the magnet poles 735 and 736 of the magnet system 730 of the electrode assembly 700, are provided to extend to the inner side of the assembly element 710, which is provided by the inner side of the encapsulation element 712 in the embodiment shown in Fig. 5.

[0045] Fig. 6a shows an embodiment of an electrode arrangement 800. The electrode arrangement includes an assembly element 810, which may be an assembly element as described in the previous figures, especially in Fig. 5. According to some embodiments, the electrode assembly 800 includes an encapsulation element 812, a magnet system 830 located within the assembly element 810 including magnet poles 835 and 836, and pole pieces 840, 841, and 842. In some embodiments, the pole pieces may extend to the inner side of the assembly element provided by the encapsulation element as described above. However, according to some embodiments, the pole piece may be composed of one or more parts extending from the magnet system to the encapsulation element and further from the encapsulation element through space 813 of the assembly element. For instance, a part of the pole pieces may be provided in the space 813 between the encapsulation element 812 and a target providing element 814 of the assembly element. As explained above, the target providing element may be made from target material, may include a target holding structure, a cathode body, a target material holding structure and the like. [0046] In Fig. 6a, a section 850 is indicated and embodiments of the section are discussed in detail with respect to Figs. 6b, 6c, and 6d. The detailed section 850 of Fig. 6b shows the magnet pole 836 of the magnet system 830, the encapsulation element 812, a target providing element 814, and the space 813 between the encapsulation element 812 and the target providing element 814 of the assembly element 810. A pole piece 841 is shown being adjacent to the magnet pole 836 of the magnet system 830. According to some embodiments, the pole piece 841 may include one or more parts. In the embodiments shown in the detailed section of Fig. 6b, the pole piece 841 includes two parts 881 and 882. In the shown example of section 850, a first part 881 of the pole piece 840 extends from the magnet pole 836 of the magnet system 830 to the encapsulation element 812 and a second part 882 of the pole piece 841 extends from the encapsulation element 812 to the target providing element 814 of the assembly element 810.

[0047] In the detailed view 850 of the embodiment shown in Fig. 6b, a distance is provided between the first part 881 of the pole piece 841 and the encapsulation element 812. Further, a distance is provided between the second part 882 of the pole piece 841 and the target providing element 814 of the assembly element 810. As generally described above, the pole piece may approximately fit to the shape of the assembly element in some embodiments described herein, such as approximately fitting to the curvature of the assembly element. In Fig. 6b, an example is given for an arrangement showing an approximate fit of the pole piece shape to the assembly shape according to embodiments described herein. In Fig. 6b, the first part 881 and the second part 882 of the pole piece 841 have a surface fitting approximately to the shape of the encapsulation element 812 and the target providing element 814. The example shown in Fig. 6b includes the first part and the second part of the pole piece having a shape adapted to the shape of the assembly element by providing inclined surfaces. [0048] The example shown in Fig. 6b shows an inclination of the first part and the second part of the pole piece by providing two inclinations having opposed signs on each of the parts of the pole piece. However, it should be understood that the inclination of the pole piece adapted to the shape of the assembly element may provide one inclination with one sign, e.g. when the pole pieces 840 or 842 are adapted to the shape of the assembly element as shown in Fig. 6a, or pole pieces 340 and 342 shown in Fig. 3.

[0049] Fig. 6c shows an example of the section 850 indicated in Fig. 6a. The same components are shown as described above with respect to Fig. 6b, except for the first part 883 and the second part 884 of the pole piece 840. The shape of the first part 883 is adapted to the shape of the encapsulation element 812. The shape of the second part 885 of the pole piece 840 is adapted to the shape of the target providing element 814. According to embodiments, the shape of the pole piece parts are adapted to the shape of the assembly element, or components thereof (such as the encapsulation element or the target providing element), by providing substantially the same curvature as the assembly element, or the respective component of the assembly element. In some embodiments, the radius of curvature of the pole piece surface may be slightly smaller than the radius of curvature of the assembly element so that a distance is provided between the pole piece and the assembly element. The distance may for instance be less than 1 mm and the radius of curvature of the pole piece may be adapted accordingly.

[0050] Fig. 6d shows an example of the section 850 indicated in Fig. 6a. The same components are shown as described above with respect to Fig. 6b, except that the first part 885 and the second part 886 of the pole piece 841 are in contact with the assembly element, especially with the encapsulation element 812 and the target providing element 814, respectively. According to some embodiments, the first part 885 of the pole piece 841 may be in contact with the encapsulation element 812 by providing lubrication between the first part 885 of the pole piece 885 and the encapsulation element 812, as exemplarily explained above with respect to Fig. 2. The same may be applied for the second part 886 of the pole piece 841 between the encapsulation element 812 and the target providing element 814.

[0051] Fig. 6e shows an example of the section 850 indicated in Fig. 6a. The same components are shown as described above with respect to Fig. 6b, except for the first part 887 of the pole piece 841 and the second part 888 of the pole piece 841. In the embodiment shown in Fig. 6e, the first part 887 being located between the magnet pole 836 and the encapsulation element 812 contacts the encapsulation element 812. The second part 888 being located between the encapsulation element 812 and the target providing element 814 provides a distance to the target providing element 814. As can be seen in the example of Fig, 6e, the shape of the second part 888 of the pole piece 841 may be adapted to the shape of the target providing element, such as by providing substantially the same curvature. [0052] It should be understood that the detailed view shows features of the parts of the pole piece 841 of Fig. 6b, 6c, 6d and 6e, but that the features, especially the features concerning the shape of the pole piece, shown and described in the detailed section 850 may also be applied to other embodiments described herein, such as embodiments referring to a pole piece with only one part.

[0053] It should also be understood that Figs. 6b to 6e show embodiments of pole pieces in the gap between the middle magnet pole 836 of the magnet system and the inner side of the assembly element. However, the design and shape of the pole pieces may be adapted to the gap provided between the outer magnet poles of the magnet system, such as magnet poles 835 in Fig. 6a, and the inner side of the assembly element (e.g. assembly element 810 in Fg.6a). For instance, the pole pieces may have a triangle-like cross section, or a trapezium-like cross section, which may depend in one embodiment on the shape of the gap between the magnet pole and the inner side of the assembly element.

[0054] According to some embodiments, a fluid, such as a cooling fluid, may be present in the space between the encapsulation element and the target providing element. In embodiments, in which the pole piece extends through the space between encapsulation element and target providing element, the pole piece, or at least a part thereof may be provided in the fluid. The pole piece, or at least a part thereof, may include a cover surrounding the pole piece, such as a coating, for avoiding a damage of the pole piece, such as the corrosion of the pole piece. The coating may for instance be a plastic coating. In some embodiments, the pole piece, especially when intended to be placed within a fluid, may be made of a ceramic material. [0055] Fig. 7 shows an embodiment of the electrode assembly 900. The electrode assembly 900 is similar to the electrode assembly shown in Fig. 6. In some embodiments, the electrode assembly 900 includes an assembly element 910, which includes an encapsulation element 912 and a target providing element 914. The electrode assembly may further include a magnet system 930 having magnet poles 935 and 936 and pole pieces 940, 941, and 942 provided between the magnet system 930 and the target providing element 814 of the assembly element 910.

[0056] As can be seen in the embodiment shown in Fig. 7, the pole pieces extend through the space 913 between the encapsulation element 912 and the target providing element 914 of the assembly element 910. As described above, the pole piece may be located in a fluid present in the space 913. In some embodiments, the pole piece may include more than one part as described in detail with respect to Fig. 6. [0057] According to some embodiments, the magnet system of Fig. 7 provides magnet poles 935 and 936 extending not parallel to each other. The magnet poles 935, 936 of the magnet system 930 extend from the magnet yoke 931 of the magnet system in an angle that is not perpendicular to the magnet yoke. Although the magnet yoke 931 is show in in a straight way, it should be understood that the features described in Fig. 9 may also be provided with a bent magnet yoke.

[0058] The term "magnet system" as used herein should be understood as an assembly including one or more magnets (e.g. one or more magnet poles, such as magnet bars, magnetic material or the like) for generating one or more magnetic fields. For instance, a magnet system may contain two magnet poles of adverse polarity, such as two magnet elements being arranged so as to generate two magnetic fields. Typically, the magnet system may be adapted for being located in an assembly element of the electrode assembly as described herein.

[0059] According to some embodiments, the electrode assembly as described herein may include two or more magnet systems being arranged in the assembly element. For instance, two magnet systems in the assembly element may be arranged so that they substantially point in opposed directions within the assembly element. In one embodiment, pole pieces may be provided between each of the magnet poles of the two or more magnet systems and the inner side of the assembly element, especially provided in a region including the shortest distance between the respective magnet pole and the assembly element.

[0060] Fig. 8a shows a cross sectional view of an example of a magnet system as may be used in the electrode assembly according to embodiments described herein. However, it should be understood that the magnet systems as referred to herein in the following are not limiting for the magnet system used in an electrode assembly according to embodiments described herein.

[0061] The example of a magnet system 500 shown in Fig. 8a includes a yoke 510. According to some embodiments, the magnet system 500 includes an inner magnet pole 520 and outer magnet poles 530 of adverse polarity. In the embodiment shown in Fig. 8a and 8b, the magnet poles 520 and 530 are shown as magnet elements 520 and 530 arranged on the yoke 510. According to some embodiments, the magnet elements may be permanent magnets. [0062] According to some embodiments, the magnet poles as described herein may be any element suitable for generating the magnetic field for forming a plasma region near the cathode assembly. In some embodiments, the magnet poles as described herein may be permanent magnets; according to further embodiments, one of the magnet poles may be provided by a magnetic material, such as a yoke made of an iron containing material.

[0063] As can be seen in Fig. 8a, the magnet elements 520 and 530 may be arranged in a way that allows for two magnetic fields being generated. A part of the two magnetic fields is shown by magnetic field lines 560 and 540. In Fig. 8a, for the sake of simplicity, only magnetic field lines are shown extending from the permanent magnets in one direction, i.e. the direction pointing away from the yoke 510.

[0064] Fig. 8b shows a top view of the magnet system 500 of Fig. 8a. In the embodiment shown in Fig, 2b, the two magnet elements 520 and 530 can be seen on the yoke 510. In the shown example, the magnet elements may be arranged so that at least one of the magnet elements forms a closed loop. In Fig. 8b, it can be seen that the magnet element 520 forms a closed loop, in which the magnet element 530 is located.

[0065] Fig. 9a shows a cross sectional view of an example of a magnet system as may be used in an electrode assembly as described herein. The magnet system 600 typically includes a yoke 610, on which magnet poles such as magnetic elements 620 and 630 may be arranged. In Fig. 9a, magnetic field lines 640 and 660 are exemplarily shown, presenting a part of the generated magnetic field.

[0066] Fig. 9b provides a top view of the magnet system 600 of Fig. 9a. An outer magnet element 620 is provided, which surrounds an inner magnet element 630. In the embodiment shown in Fig. 9b, the inner magnet element as well as the outer magnet element is arranged in a loop-shape. Both magnet elements 620 and 630 are located on the yoke 610. [0067] In some embodiments, a magnet pole of the magnet system as described herein points into a direction outside the plane defined by the magnet yoke. Generally, the magnet pole points in the direction of the target material of an electrode assembly.

[0068] As described herein, a pole piece is provided between the magnet system and the assembly element of an electrode assembly according to embodiments described herein. It should be understood that the pole piece may be located adjacent (e.g. directly adjacent) to the magnet system, and in particular to the magnet poles of the magnet system. In some embodiments, a pole piece is provided on each magnet pole of the magnet system, e.g. on magnet poles 620 and 630 as shown in Fig. 9a and 9b. According to some embodiments, more than one, such as two pole pieces, may be provided for each magnet pole of the magnet system. For instance, as can be seen in Figs. 2 to 7, pole pieces 240 and 242 are provided for magnet pole 235, pole pieces 340 and 342 are provided for magnet pole 335, pole pieces 440 and 442 are provided for magnet pole 435 and so on. In some embodiments, the pole piece may be attached to the magnet system by means of an adhesive or by magnetic forces. The pole piece being between the magnet system and the assembly element may be understood as at least partially filling a gap between the magnet system and the assembly element, or as being present in the space between the magnet system and the assembly element.

[0069] According to some embodiments, the assembly element as described herein may be used for a rotatable target during static deposition. That means that the substrate may be held in a fix position during the deposition process, whereas the target may rotate around its rotary axis (such as axis 220 in Fig. 2). For instance, the electrode assembly shown herein may be used for coating large area substrates.

[0070] According to some embodiments, large area substrates may have a size of at least

0.174 m². Typically the size can be about 1.4 m 2 to about 8 m 2 , more typically about 2 m 2 to about 9 m² or even up to 12 m². Typically, the substrates, 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 can be GEN 5, which corresponds to about 1.4 m substrates (1.1 m x 1.3 m), GEN

7.5, which corresponds to about 4.29 m 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 m 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.

[0071] A substrate as described herein may be made from any material suitable for material deposition. For instance, the substrate may be made from a material selected from the group consisting of glass (for instance soda-lime glass, borosilicate glass etc.), metal, polymer, ceramic, compound materials, carbon fiber materials or any other material or combination of materials which can be coated by a deposition process. [0072] According to some embodiments, the deposition material may be chosen according to the deposition process and the later application of the coated substrate. For instance, the deposition material of the target may be a material selected from the group consisting of: a metal, such as aluminum, molybdenum, titanium, copper, or the like, silicon, indium tin oxide, and other transparent oxides. Typically, the target material may be an oxide ceramic, more typically, the material may be a ceramic selected from the group consisting of an indium containing ceramic, a tin containing ceramic, a zinc containing ceramic and combinations thereof. For instance, the deposition material may be IGZO (indium gallium zinc oxide) or ΓΓΟ (indium tin oxide).

[0073] Fig. 10 shows a flow chart 1000 of a method for assembling an electrode assembly with a magnet system according to embodiments described herein. In block 1010, an electrode assembly including an assembly element is provided. In some embodiments, the electrode assembly used in the method described herein may be an electrode assembly as described above, especially with respect to Figs. 2 to 7. The assembly element is adapted for providing a cylindrical target and/or holding a rotatable target.

[0074] The method includes in block 1020 positioning a magnet system within the assembly element. According to some embodiments, the magnet system may include magnet poles for generating a magnetic field. The magnet system used in the method described herein may be a magnet system as described above with regard to Figs. 2 to 7, especially a magnet system as described with respect to Figs. 8a to 9b. In some embodiments, the magnet system may be arranged rotatably within the assembly element. In some embodiments, positioning the magnet system in the assembly element may include generating a magnetic field by the magnet system. For instance, one or more magnetic fields may be generated extending through the assembly element, and especially extending beyond the outer side of the assembly element, i.e. the side of the assembly element facing the substrate. Generally, positioning the magnet system within the assembly element may include influencing a plasma formation outside the assembly element with the magnetic field generated by the magnet system within the assembly element.

[0075] In block 1030, the method includes mounting a pole piece between the assembly element and the magnet system. According to some embodiments, the pole piece may be mounted adjacent to the magnet system, in particular directly adjacent to the magnet system.

The pole piece mounted between the magnet system and the assembly element may stand in direct contact with the magnet system, especially with a magnet pole of the magnet system. In one example, the mounted pole piece may provide a defined distance to the assembly element. In another example, the pole piece may be in contact with the assembly element. In the case that the mounted pole piece stands in contact with the assembly element, mounting the pole piece in a method according to embodiments described herein may include providing lubrication, such as Teflon to the pole piece, the assembly element or both.

[0076] In some embodiments, mounting the pole piece may include attaching the pole piece to the magnet system, such as using an adhesive or magnetic forces. Mounting the pole piece may further include mounting one or more pole pieces to each magnet pole of the magnet system, as explained above and shown in Figs. 2 to 7.

[0077] Fig. 11 shows a flow chart 1050 of a method for assembling an electrode assembly. Blocks 1010, 1020, and 1030 may correspond to the respective blocks described in detail with regards to Fig. 10. The flow chart 1050 shows a further block 1035 specifying mounting the pole piece. Block 1035 refers to mounting the pole piece so that the pole piece fits to the inner shape of the assembly element. According to some embodiments, the inner shape of the assembly element may be substantially cylindrical as described and explained in detail above. The pole piece in block 1035 may be adapted for matching the inner shape of the assembly element, for instance by complementing the inner shape of the assembly element. In one example, the inner side of the assembly may have a curvature and the pole piece, especially the end of the pole piece facing the inner side of the assembly element may have a complementing curvature.

[0078] According to some embodiments, the pole piece is mounted so as to fill a gap between the magnet system and the assembly element. In some embodiment, the pole piece may fill the gap by having a shape being adapted to the shape of the gap between the magnet system, especially a magnet pole of the magnet system, and the assembly element, especially the inner side of the assembly element. In one example, the pole piece may fill the gap by extending and confining the magnetic field outside the assembly element.

[0079] In one embodiment, the use of an electrode assembly as described in embodiments herein is provided. The use of an electrode assembly according to embodiments described herein may take place in a sputter process apparatus, such as a sputter deposition chamber and the like. [0080] In some embodiments described herein, the pole pieces are used in an electrode assembly to get a fitting between the rectangular shape of the magnet poles of the magnet system and the substantially round surface of the tube. The electrode assembly according to embodiments described herein allows for using smaller magnet systems compared to known systems and achieving an effective and directed magnetic field outside the assembly element. On the other hand, the electrode assembly according to embodiments described herein allows for a stronger magnetic field outside the assembly element without the need for stronger or larger magnet systems.

[0081] 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. Electrode assembly (120; 200; 300; 400; 700; 800; 900) for a sputter deposition

apparatus, the electrode assembly comprising: an assembly element (210; 310; 410; 710; 810; 910) for at least one of providing material to be deposited and holding a rotatable target; a magnet system (230; 330; 430; 730; 830; 930) disposed inside the assembly element (210; 310; 410; 710; 810; 910); and a pole piece (240; 241; 242; 340; 341; 342; 440; 441; 442; 740; 741; 742; 840; 841; 842; 940; 941; 942) for being disposed between the magnet system and the assembly element.

2. The electrode assembly according to claim 1, wherein the assembly element (210;

310; 410; 710; 810; 910) is a target holding structure for holding a rotatable target.

3. The electrode assembly according to claim 1, wherein the assembly element (210;

310; 410; 710; 810; 910) is a cylindrical cathode body, particularly for holding a target.

4. The electrode assembly according to any of claims 1 to 3, wherein the inner side (211;

311; 711) of the assembly element (210; 310; 410; 710; 810; 910) is substantially cylindrical.

5. The electrode assembly according to any of claims 1 to 4, wherein the shape of the pole piece (240; 241; 242; 340; 341; 342; 440; 441; 442; 740; 741; 742; 840; 841; 842; 940; 941 ; 942) is adapted to the shape of the inner side (211 ; 311 ; 711) of the assembly element (210; 310; 410; 710; 810; 910), in particular wherein the shape of the pole piece (240; 241; 242; 340; 341; 342; 440; 441; 442; 740; 741; 742; 840; 841; 842; 940; 941 ; 942) facing the inner side (211 ; 311 ; 711) of the assembly element (210; 310; 410; 710; 810; 910) corresponds to the shape of the inner side of the assembly element.

6. The electrode assembly according to any of claims 1 to 5, wherein the pole piece (240; 241; 242; 340; 341; 342; 440; 441; 442; 740; 741; 742; 840; 841; 842; 940; 941; 942) substantially fills a gap (271) between the magnet system (230; 330; 430; 730; 830; 930) and the inner side (211; 311; 711) of the assembly element (210; 310; 410; 710; 810; 910), particularly wherein the gap (271) has a length of less than about 20 mm.

7. The electrode assembly according to any of claims 1 to 6, wherein the pole piece (240;

241; 242; 340; 341; 342; 440; 441; 442; 740; 741; 742; 840; 841; 842; 940; 941; 942) has a distance of less than 1 mm to the inner side (211; 311; 711) of the assembly element (210; 310; 410; 710; 810; 910), or wherein the pole piece is in contact with the inner side of the assembly element.

8. The electrode assembly according to any of claims 1 to 7, wherein the assembly

element (210; 310; 410; 710; 810; 910) comprises an encapsulation element (312, 712; 812; 912) encapsulating the magnet system (230; 330; 430; 730; 830; 930) and the pole piece (240; 241; 242; 340; 341; 342; 440; 441; 442; 740; 741; 742; 840; 841; 842; 940; 941; 942) and/or wherein the assembly element (210; 310; 410; 710; 810; 910) comprises an

encapsulation element (312, 712; 812; 912) encapsulating the magnet system (230; 330; 430; 730; 830; 930) and the pole piece (240; 241; 242; 340; 341; 342; 440; 441; 442; 740; 741; 742; 840; 841; 842; 940; 941; 942), and a target providing element (814; 914), and wherein a further pole piece is provided between the encapsulation element (312, 712; 812; 912) and the target providing element (814; 914).

9. The electrode assembly according to any of claims 3 to 8, wherein the cathode body comprises at least one of a target, a target with a material to be deposited and a backing tube for a target with a material to be deposited.

10. The electrode assembly according to any of claims 1 to 9, wherein the magnet system (230; 330; 430; 730; 830; 930) comprises at least a first end (235; 335; 435; 735; 835; 935) and a second end (236; 336; 436; 736; 836; 936) and wherein a pole piece (240; 241; 242; 340; 341; 342; 440; 441; 442; 740; 741; 742; 840; 841; 842; 940; 941; 942) is provided between the assembly element and each end of the magnet system.

11. The electrode assembly according to claim 10, wherein each pole piece (240; 241; 242; 340; 341; 342; 440; 441; 442; 740; 741; 742; 840; 841; 842; 940; 941; 942) being provided between an end (235; 335; 435; 735; 835; 935) of the magnet system (230; 330; 430; 730; 830; 930) and the assembly element (210; 310; 410; 710; 810; 910) is adapted to the shape of the inner side of the assembly element.

12. The electrode body according to any of claims 1 to 11, wherein the magnet system (230; 330; 430; 730; 830; 930) comprises a yoke (931; 510; 610) and two permanent magnets (235; 335; 435; 520; 530; 620; 630; 735; 835; 935) of adverse polarity.

13. Method for assembling an electrode assembly with a magnet system (230; 330; 430;

730; 830; 930), the electrode assembly comprising an assembly element (210; 310;

410; 710; 810; 910) for at least one of providing a cylindrical target and holding a rotatable target, the method comprising: positioning a magnet system (230; 330; 430; 730; 830; 930) within the assembly element (210; 310; 410; 710; 810; 910); and mounting a pole piece (240; 241; 242; 340; 341; 342; 440; 441; 442; 740; 741; 742;

840; 841; 842; 940; 941; 942) between the assembly element and the magnet system.

14. The method according to claim 13, wherein mounting the pole piece (240; 241; 242;

340; 341; 342; 440; 441; 442; 740; 741; 742; 840; 841; 842; 940; 941; 942) further comprises mounting the pole piece so as to substantially fill a gap between the inner side of the assembly element (210; 310; 410; 710; 810; 910) and the magnet system.

15. The method according to any of claims 13 to 14, wherein mounting the pole piece (240; 241; 242; 340; 341; 342; 440; 441; 442; 740; 741; 742; 840; 841; 842; 940; 941; 942) further comprises mounting the pole piece so that the pole piece fits to the inner shape of the assembly element (210; 310; 410; 710; 810; 910).