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DE-102024133217-A1 - Magnetron cathode with heat sink and cooling device for a magnetron cathode

DE102024133217A1DE 102024133217 A1DE102024133217 A1DE 102024133217A1DE-102024133217-A1

Abstract

The invention relates to a magnetron cathode (10) with a metal heat sink (14) having a flat top surface (20), and to a cooling device (12) for a magnetron cathode (10). A plate-shaped target (18) is placed on the top surface (20) of the heat sink (14). A recess (22) is formed in the top surface (20) of the heat sink (14), in which a magnetic assembly (24) with one or more magnetic elements (28) is arranged. An air gap (42) is arranged between the magnetic assembly (24) and the target (18).

Inventors

  • Oliver Lemmer
  • Stephan Bolz

Assignees

  • CEMECON AG.

Dates

Publication Date
20260513
Application Date
20241113

Claims (15)

  1. Magnetron cathode (10), comprising: - a metal heat sink (14) with a flat top surface (20); - a plate-shaped target (18) placed on the top surface (20) of the heat sink (14); - a recess (22) is formed in the top surface (20) of the heat sink (14) in which a magnet assembly (24) with one or more magnet elements (28) is arranged; - an air gap (42) is arranged between the magnet assembly (24) and the target (18).
  2. Magnetron cathode after Claim 1 , wherein - the plate-shaped target (18) is arranged with a target backside (40) on the top side (20) of the heat sink (14), - wherein the size of a contact area between the target backside (40) and the top side (20) of the heat sink (14) is smaller than the size of the area of the target backside (40).
  3. Magnetron cathode according to one of the preceding claims, wherein - the recess (22) has a closed bottom recessed relative to the top (20) of the heat sink (14).
  4. Magnetron cathode according to one of the preceding claims, wherein - the magnet assembly (24) comprises a plurality of magnetic elements (26) arranged in the recess (22).
  5. Magnetron cathode after Claim 4 , in which - a majority of the magnetic elements (26) are covered in the direction of the top (20) by a flat, ferromagnetic cover element (30) and the air gap (42) is arranged between the cover element (30) and the target (18).
  6. Magnetron cathode according to one of the preceding claims, wherein - the recess (22) has an undercut (34) effective in the direction of the top (20) and at least one magnetic element (26) is arranged in the recess (22) in such a way that it lies at least partially under the undercut (34).
  7. Magnetron cathode according to one of the preceding claims, wherein - the recess is formed at least sectionally as a groove (22).
  8. Magnetron cathode after Claim 7 , in which - the groove (22) forms a closed track on the top (20) of the heat sink (14).
  9. Magnetron cathode according to one of the preceding claims, wherein - the air gap (42) has a height of at least 0.5 mm.
  10. Magnetron cathode according to one of the preceding claims, wherein - the air gap (42) is arranged at least partially within the recess (22).
  11. Magnetron cathode according to one of the preceding claims, wherein - the plate-shaped target (18) is arranged with a target back side (40) on the top side (20) of the heat sink (14), - and at least one recess (156) is formed on the target back side (40), - wherein the recess (156) on the target back side (40) is arranged opposite the depression (22) in the top side (20) of the heat sink (14), such that the air gap (42) is arranged at least partially in the recess (156).
  12. Magnetron cathode according to one of the preceding claims, wherein - at least one coolant channel (16) is arranged on the heat sink (14), - the coolant channel (16) is arranged at least sectionally opposite the recess (22).
  13. Magnetron cathode after Claim 12 , wherein - the coolant channel (16) has a wall (46) and an interior (48), wherein the wall (46) forms an open cross-section, - and wherein the wall (46) of the coolant channel (16) is arranged on a flat underside (44) of the heat sink (14) such that a part of the underside (44) is in contact with the interior (48).
  14. Magnetron cathode according to one of the preceding claims, wherein - the heat sink (14) and the target (18) have an elongated, rectangular shape, - and the recess (22) has at least a first and a second straight groove section, wherein the first and second groove sections run parallel to each other at a distance from each other in the longitudinal direction of the heat sink (14).
  15. Cooling device (12) for a magnetron cathode (10), comprising - a metal heat sink (14) with a flat top (20) for positioning a plate-shaped target (18), - wherein a recess (22) is formed in the top (20) of the heat sink (14) in which a magnet assembly (24) with one or more magnetic elements (28) is arranged, - wherein an air gap (42) is arranged in the recess (22) above the magnet assembly (24) and below the height of the top surface (20).

Description

The invention relates to a magnetron cathode, such as that used in magnetron sputtering processes, and a cooling device for a magnetron cathode. A target made of a sputtering material is typically attached to a magnetron cathode, which is sputtered by ions in a vacuum. A magnetic assembly serves to deflect the ions. The DE 10018858 A1 This describes a magnetron array with a target, beneath which support elements, a magnet system, and a cooling system with a cooling plate are arranged. To improve the homogeneity of heat transfer, heat transfer occurs primarily in the form of thermal radiation. The task can be seen as proposing a magnetron cathode and a cooling device for it, in which a favorable arrangement of the various components is given, especially with regard to heat transport. With regard to the problem, the invention proposes a magnetron cathode according to claim 1 and a cooling device according to claim 15. Dependent claims relate to advantageous embodiments of the invention. The magnetron cathode according to the invention comprises at least one heat sink, a plate-shaped target and a magnet assembly. The heat sink is made of metal, in particular a highly thermally conductive metal such as aluminum or, more preferably, copper, or of an alloy with copper and/or aluminum as the main component. The heat sink has a flat top surface, which is the side facing the target. The target is plate-shaped and placed on the top of the heat sink, such that at least a substantially flat underside of the target is in contact with the flat top of the heat sink. This can be direct contact of the surfaces, or alternatively, indirect contact with an intermediate layer, e.g., in the form of a thin, flexible film that supports the mounting and heat transfer. The target is preferably detachably attached to the heat sink, for which target mounting means may be provided. The target mounting means are preferably clamping elements that press the target firmly against the heat sink to achieve a tight fit and good heat transfer. The target mounting means designed as clamping elements can be of various designs and may, for example, include one or more clamping devices; preferably, a plurality of screw connections are used. The top surface of the heat sink has at least one recess in which a magnetic assembly with one or, preferably, several magnetic elements is arranged. The recess is preferably located within the top surface, i.e., at a distance from the edges. The magnetic elements of the magnetic assembly are preferably permanent magnets, particularly preferably samarium-cobalt magnets. Preferably, the magnetic assembly is arranged completely within the recess, i.e., recessed relative to the top surface of the heat sink. According to the invention, an air gap is arranged between the magnet assembly and the target. As will be explained in more detail below, the air gap can be formed, for example, by an arrangement of the magnet assembly recessed by a certain amount in the recess, by a recess in the target, or by both. The cooling device according to claim 15 for a magnetron cathode comprises a metal heat sink with a flat top surface for positioning a plate-shaped target. A recess is formed in the top surface of the heat sink, in which a magnetic assembly with one or more magnetic elements is arranged. An air gap is arranged in the recess above the magnetic assembly and below the height of the top surface. When the plate-shaped target is placed on the top surface, the air gap between the magnetic assembly and the target is thus formed. The magnetron cathode and cooling device according to the invention thus enable the magnet assembly to be arranged in the immediate vicinity of the target, so that a strong magnetic field can be achieved in the target area. The flat contact of the target with the top of the heat sink ensures good heat transfer. Nevertheless, the air gap between the magnet assembly and the target creates a certain thermal barrier, thus reducing or preventing direct heat conduction from the target to the magnet assembly. In this way, excessive heat stress on the magnet assembly is avoided. The recess on the top of the heat sink preferably reduces the contact area between the target and the heat sink, i.e., the target and heat sink are not in full contact with each other. The target is in contact over its entire surface because there is no contact in the area of the recess. Here, "contact" is understood to mean either direct contact, i.e., direct contact of the bodies against each other, or indirect contact via an interposed thin contact film. According to a further development of the invention, the plate-shaped target is arranged with a target backing on the top surface of the heat sink, wherein the size of the contact area between the target backing and the top surface of the heat sink is smaller than the area of the target backing. The area of the target backing is preferably considered to be the surface lying in a