ROTARY MAGNETRON SPUTTERING WITH INDIVIDUALLY ADJUSTABLE MAGNETIC FIELD

Abstract

A rotary cathode assembly for a magnetron sputtering apparatus is provided. The rotary cathode assembly includes a magnetron assembly having a plurality of magnets attached to a plurality of yokes, a plurality of driving modules each comprising an actuating mechanism operatively coupled to at least one of the plurality of yokes, and a protective tube, wherein the plurality of driving modules are adapted for adjusting the position of the plurality of yokes individually. The rotary cathode assembly further includes a hollow target cathode enclosing the protective tube and defining a passage formed between an inner surface of the hollow target cathode and an outer surface of the protective tube, wherein the ends of the target cathode assembly are configured to be rotatably attachable to the magnetron sputtering apparatus.

Claims

1. A rotary cathode assembly for a magnetron sputtering apparatus, the rotary cathode assembly comprising: a magnetron assembly for magnetron sputtering comprising a plurality of magnets attached to a plurality of yokes, a plurality of driving modules each comprising an actuating mechanism operatively coupled to at least one of the plurality of yokes, and a protective tube, wherein the plurality of driving modules are adapted for adjusting the position of the plurality of yokes individually; and a hollow target cathode enclosing the protective tube of the magnetron assembly and defining a passage formed between an inner surface of the hollow target cathode and an outer surface of the protective tube, wherein the ends of the target cathode assembly are configured to be rotatably attachable to the magnetron sputtering apparatus.

2. The rotary cathode assembly according to claim 1, wherein the magnetron assembly is adapted for adjusting the position of the plurality of yokes individually with respect to a corresponding distance to an inner surface of the protective tube.

3. The rotary cathode assembly according to claim 1, wherein the passage formed between the inner surface of the hollow target cathode and the outer surface of the protective tube receives cooling fluid from at least one cooling fluid pipe of the magnetron assembly by a fluid guide placed in an end of the rotary cathode assembly.

4. The rotary cathode assembly according to claim 1, wherein: a first end of the rotary cathode assembly comprises a means for transferring light signals between the magnetron sputtering apparatus and the magnetron assembly; and/or a second end of the rotary cathode assembly comprises a means for supplying a coolant fluid to at least one pipe of the magnetron assembly, and a means for receiving the coolant fluid from the passage formed between the inner surface of the hollow target cathode and the outer surface of the protective tube.

5. The rotary cathode assembly according to claim 4, wherein the light signals sent and received through the first end of the rotary cathode assembly are carried by at least one optical fiber.

6. The rotary cathode assembly according to claim 5, wherein at least one of the light signals sent and received through the first end of the rotary cathode assembly corresponds to a control signal that determines displacement of each individual yoke with respect to an inner surface of the protective tube.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0027] Illustrative embodiments of the present invention are further explained by way of example only, and not for limitation, with respect to the accompanying drawings in which like reference numerals refer to similar elements. It is mentioned that the various features are not necessarily drawn to scale. In the drawings:

[0028] FIG. 1 shows a first embodiment of a sputtering apparatus in a cross-sectional view, comprising a magnetron assembly and a rotary cathode assembly according to the present invention;

[0029] FIG. 2A shows the rotary cathode assembly of the first embodiment according to an aspect of the invention;

[0030] FIG. 2B is a sectional view of the rotary cathode assembly of FIG. 2A;

[0031] FIG. 3A a second embodiment of the invention for a magnetron assembly comprised in a rotary cathode assembly with the protective tube removed, according to another aspect of the invention;

[0032] FIG. 3B shows a first end view of the magnetron assembly of FIG. 3A with the protective tube removed;

[0033] FIG. 3C shows a second end view of the magnetron assembly of FIG. 3A with the protective tube removed;

[0034] FIG. 3D shows an enlarged view of an exemplary actuating mechanism of the magnetron assembly of FIG. 3A;

[0035] FIG. 3E shows another enlarged view of an exemplary actuating mechanism of the magnetron assembly of FIG. 3A;

[0036] FIG. 4A depicts a third embodiment showing the magnetron assembly with the protective tube removed;

[0037] FIG. 4B shows an enlarged sectional view of an end portion of the magnetron assembly in area A of FIG. 4A; and

[0038] FIG. 5 shows a flow chart of a representative embodiment of the inventive method according to the third aspect of the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0039] The present invention will be described with respect to particular embodiments and with reference to certain drawings but the invention is not limited thereto. In the description and in the claims, the indefinite article a or an does not exclude a plurality. Furthermore, the terms first, second and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequence, either temporally, spatially, in ranking or in any other manner. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other sequences than described or illustrated herein.

[0040] Moreover, the terms top, under and the like in the description and the claims are generally employed for descriptive purposes and not necessarily for comprehensively describing exclusive relative positions. It is to be understood that any of the preceding terms so used may be interchanged under appropriate circumstances such that various embodiments of the invention described herein are capable of operation in other configurations and/or orientations than those described or illustrated herein.

[0041] FIG. 1 shows an overall schematic representation of a sputtering apparatus 100 according to one embodiment of the invention, which is configured for magnetron sputtering with rotary cathodes. The sputtering apparatus 100 comprises a substrate 101 placed within a vacuum chamber 102 having an outer wall 104. The substrate 101 to be coated is guided to pass below a rotary cathode assembly 103 by using, for example, a conveyor 105 having a plurality of rollers 106. The substrate 101 refers to large-area substrates, for example flat glass but not limited to glass.

[0042] A first end 107 of the rotary cathode assembly 103 within the vacuum chamber 102 is rotatably attached, through a shaft 108, to a drive structure 109 that is adapted to rotate the rotary cathode assembly 103 and all its components, which will be described below in the description, about its main axis. The drive structure 109 may be embodied, for example, in the form of a toothed belt drive or motorized gears or the like mechanism. The vacuum chamber 102 is sealed with respect to a housing 110 supporting the drive structure 109.

[0043] As it can be noted in FIG. 1, a coolant fluid inlet and outlet 112 is provided at a second end 111 of the rotary cathode assembly 103. The coolant fluid inlet and outlet 112 can be arranged in a housing 113, which is sealed relative to the vacuum chamber 102. In addition to this, the second end 111 of the rotary cathode assembly 103 is rotatably attached, using a bearing 114, to the housing 113.

[0044] In this exemplary embodiment, the sputtering apparatus 100 enables transmission of light signals from outside the vacuum chamber 102 and/or to outside the vacuum chamber 102. The light signals are carried by at least one optical fiber 115 provided at the first end 107 of the rotatable target cathode assembly 103.

[0045] The at least one optical fiber 115 is coupled to at least one external optical fiber 116 outside the vacuum chamber 102, which in turn is in operative communication to an external optical communications systems (not shown), which for example can be further coupled to the substrate 101 after being coated, so that any non-uniformities are detected.

[0046] FIGS. 2A and 2B illustrate the rotary cathode assembly 103 in accord with an aspect of the present invention, which comprises a magnetron assembly 202 having a protective tube 203 enclosed by a hollow target cathode 201, forming a passage 204 between the inner surface 222 of said hollow target cathode 201 and the outer surface 221 of the protective tube 203. The hollow target cathode also comprises a target material 219.

[0047] As it will be discussed in detail below, the magnetron assembly 202 comprises a plurality of magnets 205 attached to a plurality of yokes 206, a plurality of driving modules 207, a plurality of actuation mechanisms 208 provided by the driving modules 207, a plurality of slave controllers 209, a master controller 210, at least one rechargeable battery 211 and at least one cooling fluid pipe 212, which are placed within the protective tube 203.

[0048] From FIGS. 2A and 2B it is noted that the at least one cooling liquid pipe 212 may be attached to an elongated support bar 213 and placed along one side of the plurality of individual yokes 206.

[0049] Especially in the context of FIG. 2A, a cooling fluid is supplied to the at least one cooling fluid pipe 212 of the magnetron assembly 202, via an inlet 214 at the second end 111 of the rotary cathode assembly 103. The cooling fluid flows along the at least one cooling fluid pipe 212, in the direction depicted by the arrows shown in FIG. 2A, until it reaches a fluid guide 215 and exits through lateral bores 216 to the passage 204 formed between the outer surface 221 of the protective tube 203 of the magnetron assembly 202 and the inner surface 222 of the hollow target cathode 201.

[0050] Then, the coolant fluid flows through the passage 204 back to the second end 111 of the rotary cathode assembly 103, where it is discharged through an outlet 217. In this manner, the rest of the components of the magnetron assembly, namely the plurality of magnets 205, the plurality of individual yokes 206, the plurality of actuation mechanisms 207, the slave controllers 209, the central controller 210, the support bar 213 and the at least one rechargeable battery 211, are protected from corrosion owing to the coolant fluid while the target is kept appropriately cooled.

[0051] Also in the context of FIG. 2A, it is mentioned that the first end 107 of the rotary cathode assembly 103 comprises means for transferring light signals between a sputtering apparatus 100 and the magnetron assembly 202. In this embodiment, the at least one optical fiber 115 may comprise a static part 115a and a rotating part 115b, which are preferably coupled through a lens 220. Furthermore, the at least one optical fiber 115 as well as its the static 115a and rotating 115b parts are sealed with respect to the coolant fluid reaching the fluid guide 215 and the lateral bores 216 at said first end 107, avoiding corrosion.

[0052] An exemplary embodiment of the inventive magnetron assembly 202 will be discussed now especially with respect to FIG. 2B, which depicts a lateral view of the magnetron assembly 202 placed within the hollow target cathode 201 of the rotary cathode assembly 103.

[0053] As mentioned before, the magnetron assembly 202 comprises a plurality of magnets 205 attached to a plurality of yokes 206. In general, the magnets 205 are formed as substantially parallel rows of permanent magnets 205 mounted on a yoke 206, as shown in FIG. 2B. Each yoke 206 can be made of a metallic material, especially a ferromagnetic material as for example steel, and may be shaped in different forms, for example in a substantially U or E shape or any other shape that allows to accommodate the magnets 205.

[0054] The magnetron assembly 202 further comprises a plurality of driving modules 207. Each driving module 207 comprises an actuating mechanism 208 operatively coupled to at least one of the plurality of yokes 206. The plurality of driving modules 207 are adapted for adjusting the position of the plurality of yokes 206 individually.

[0055] In this exemplary embodiment, the plurality of driving modules 207, and therefore the plurality of yokes 206, are attached along an elongated support bar 213, so that the driving modules 207 displace the yokes 206 individually and essentially in a perpendicular manner with respect to the elongated support bar 213.

[0056] In this context, it is mentioned that the individual yokes 206 each can have a length, for example, between 100 mm and 300 mm, preferably between 100 mm and 200 mm, and their displacement can be, by way of example, between 5 mm and 30 mm, preferably 12 mm. The plurality of yokes 206 have not necessarily the same length, but each yoke 206 may have a different length. Moreover, the intensity of the magnetic field at each of the plurality of yokes 206 can be of the order of some milliteslas.

[0057] With regard to FIG. 2B, it is noted that when the magnetron assembly 202 having a protective tube 203 is placed within the hollow target cathode 203, each of the actuating mechanisms 208 displaces at least one of the yokes 206 towards the inner surface 218 of the protective tube 203 essentially in a perpendicular manner with respect to the elongated support bar 213. Alternatively, each of the actuating mechanisms 208 displaces at least one of the yokes 206 from the inner surface 218 of the protective tube 203 toward the elongated support bar 213, in an essentially perpendicular manner with respect to said elongated support bar 213.

[0058] Hence, such a displacement of the yokes 206 vary the distance of the magnets 205 to/from the hollow target cathode 201, enabling to locally control the intensity of a magnetic field generated by the magnets 205 which in turn modifies a generated plasma and therefore allows to control the coating uniformity when the rotary cathode assembly 201 is employed within a sputtering apparatus 100, as shown in FIG. 1.

[0059] As mentioned previously, the inventive magnetron assembly 202 further comprises a plurality of slave controllers 209, each of which is in operative communication with a driving module 207. The plurality of slave controllers 209 are connected to a master controller 210. Especially, the master controller 210 is adapted to send and receive signals to and from outside the magnetron assembly 202, respectively, which are light signals carried by the at least one optical fiber 115, especially its rotating part 115b, which is passed through an optical-electrical signal converter 117.

[0060] Moreover, each driving module 207 displaces the yokes 206 in accordance with signals received from the master controller 210 through a corresponding slave controller 209, sending a confirmation signal back to the master controller 210 after the corresponding yoke 206 has been displaced.

[0061] It is also mentioned that the master controller 210 may receive a signal from outside a sputtering apparatus 100, through at least an external optical fiber 116, which comprises information regarding any coating non-uniformities on a substrate 101 to be corrected by displacing at least one of the plurality of yokes 206.

[0062] The at least one rechargeable battery 211, which is in operative communication with the driving modules 207, is configured to energize the actuation mechanisms 208, the slave controllers 209 and the master controller 210.

[0063] FIGS. 3A to 3C depict a second embodiment of the inventive magnetron assembly 202 with the protective tube 203 removed for the sake of clarity. In the context of FIG. 3A, it is mentioned that the at least one rechargeable battery 211 may be charged externally, for example through a plug 305 shown in FIG. 3C. This is beneficial, since charging and replacement of the at least one rechargeable battery 211 can be performed for example during equipment maintenance, saving time and operation costs. The battery 211 might alternatively be charged by an internal generator driven by a turbine rotated by the flow of the cooling fluid.

[0064] The actuating mechanisms 208 provided by the plurality of driving modules 207 may comprise at least one actuator 301, as depicted in FIGS. 3D and 3E, which can be controlled separately from the other actuators. The at least one actuator 301 can be implemented, for example, as a motorized actuator, a hydraulic actuator, a pneumatic actuator, a piezoelectric actuator or the like.

[0065] By way of example, FIG. 3D shows that the at least one actuator 301 is implemented as a step motor linear actuator 302. The step motor linear actuator 302 is adapted to displace a corresponding yoke 206 away from and/or toward the elongated support bar 213 in accord with a signal received through a slave controller 209 form the master controller 210.

[0066] In general, the at least one actuator 301 also comprises at least one stopper 304, as depicted in FIG. 3E, defining a maximum and a minimum displacement of a corresponding yoke 206 with respect to the elongated support bar 213. Such a maximum or minimum displacement may be determined in additional ways, for example by means counting the number of steps of the motor in the case that the at least one actuator is a step motor linear actuator 302, or by a predetermined light signal transmitted to/from outside a sputtering apparatus 100, or by other mechanisms.

[0067] The at least one actuator 301 may also comprise at least one vertical pin 303, exemplary two pins 303 shown in FIG. 3D, which prevents tilting of a corresponding yoke 206 while being displaced.

[0068] FIGS. 4A and 4B illustrate a third embodiment of the magnetron assembly 202 where the protective tube 203, the slave controllers 209, the master controller 210 and the at least one rechargeable battery 211 were removed for clarity.

[0069] Especially, FIG. 4B shows a receiver 402 placed at one of the ends of the magnetron assembly 202 in the area A of FIG. 4A, which receives the at least one optical fiber 115 carrying light signals sent and received by the central controller 210. In this embodiment, the receiver 402 is in optical communication directly with the optical fiber static part 115a or alternatively with the lens 220 and, thus, the optical fiber rotary part 115b and the optical-electrical converter 117 as described in the embodiment shown in FIG. 2A, are rendered superfluous. This is beneficial, since complexity is reduced.

[0070] FIG. 4B further shows a rotary shaft seal 403 which enables to rotatably attach the rotary cathode assembly 103, enclosing the magnetron assembly 202, to a vacuum chamber 102 of a sputtering apparatus 100 as depicted in FIG. 1.

[0071] Also when enclosed within a rotary cathode assembly 103, the at least one cooling fluid pipe 212 of the magnetron assembly 202 is adapted to receive cooling fluid from a sputtering apparatus 100, as explained before, through a receptacle 401 depicted in FIG. 4A, in which a plurality of bracket assemblies 404 for the actuating mechanisms 208 are also shown.

[0072] Now, a flow chart of an embodiment of the inventive method is shown in FIG. 5. In a first step S100, a plurality of magnets 205 attached to a plurality of yokes 206 are provided. In a second step S101, a plurality of driving modules 207, each comprising an actuating mechanism 208 are also provided. The inventive method may further comprise that the driving modules 207 are attached to a supporting bar 213.

[0073] In a third step S102, each actuating mechanism 208 is operatively coupled to at least one of the plurality of yokes 206. In a subsequent step S103, the driving modules 207 are configured, through the actuating mechanisms 208, to adjust the positions of the plurality of yokes 206 individually.

[0074] The method may further comprise the optional steps of placing the magnetron assembly 202, having a protective tube 203, within a hollow target cathode 201 and defining a passage formed between the inner surface 222 of the hollow target cathode 201 and the outer surface 221 of the protective tube 203, and adjusting the position of the plurality of yokes individually with respect to their corresponding distance to the inner surface of a protective tube enclosed by the hollow target cathode. In this manner, the distance between the magnetic field generated by the magnetron assembly 202 and a hollow target cathode 201 is locally adjusted, enabling controlling and correcting any non-uniformities in the coating obtained on a substrate 101.

[0075] Finally, it is mentioned that throughout the present disclosure it is not excluded that an actuating mechanism 208 may also be adapted to displace groups of yokes 206 at a time. Also, it is not excluded that more than one actuating mechanisms 208 may be adapted to displace a single yoke 206. By way of example, two or more yokes 206 can be displaced simultaneously by an actuating mechanism 208, or any combination thereof.

[0076] While various embodiments of the present invention have been described above, it should be understood that they have been presented by way of example only, and not limitation. Numerous changes to the disclosed embodiments can be made in accordance with the disclosure herein without departing from the scope of the invention. Thus, the breadth and scope of the present invention should not be limited by any of the above described embodiments. Rather, the scope of the invention should be defined in accordance with the appended claims and their equivalents.

[0077] Although the invention has been illustrated and described with respect to one or more implementations, equivalent alterations and modifications will occur to others skilled in the art upon the reading and understanding of this specification and the annexed drawings. In addition, while a particular feature of the invention may have been disclosed with respect to only one of several implementations, such feature may be combined with one or more other features of the other implementations as may be desired and advantageous for any given or particular application.