Rotatable sputtering apparatus.

Rotary sputtering device and cathode

The present invention broadly relates to a sputtering device comprising a magnetron cathode, and in particular to a sputtering cathode for sputter coating a non-planar substrate, the cathode comprising a rotatable, elongate, tubular portion having a layer of sputterable coating material applied to its outer surface.

U.S. Patent 4,356,073 discloses a rotatable magnetron cathode operating in a coating chamber in which gas can be removed, said cathode comprising an elongate, cylindrical, tubular portion having substantially the same diameter along its entire length and being provided with a coating material layer, coat on substantially planar substrates as they move relative thereto.

The present invention relates to a rotating magnetron cathode of a substantially different type, in which the elongate, tubular part of the cathode is shaped in the longitudinal direction so as to form a non-cylindrical sputtering surface.

Another object of the invention is to provide a rotatable magnetron cathode in which an elongate tubular portion is provided with a longitudinally curved sputtering surface for sputtering coatings of substrate surfaces having substantially the same curvature.

It is an object of the invention to provide a rotatable magnetron cathode having a substantially barrel-shaped shape so that it is relatively wider at the center than at the ends.

It is a further object of the invention to provide rotors2

799 A magnetron cathode with a non-cylindrical profile that can be used to sputter coat bent or curved surfaces.

The invention relates to a sputtering cathode for sputtering a coating of non-planar substrates, which cathode comprises a rotatable, elongate, tubular part having a layer of sputterable coating material applied to its outer surface, characterized in that the tubular part is shaped .

The invention further relates to a sputtering device comprising a magnetron cathode, comprising a coating chamber from which gas can be removed, a sputtering cathode as described at the beginning, a magnetic device mounted inside the tubular part, the sputtering device further comprising a device for rotating the tubular part in the direction of which is perpendicular to its longitudinal axis. The device is characterized by what is set forth in the characterizing part of claim 7.

Figure 1 is a longitudinal vertical section through a coating chamber to which is attached a rotatable magnetron cathode constructed in accordance with the present invention.

Figure 2 is a transverse vertical section substantially along line 2-2 in Figure 1.

Figure 3 is a transverse vertical section substantially along line 3-3 in Figure 1.

Figure 4 is a cross-sectional vertical section taken substantially along line 4-4 in Figure 1.

7991 7

Referring to the drawing, reference numeral 10 denotes a coating chamber from which gas can be removed, and reference numeral 11 denotes a rotatable magnetron cathode provided by the invention attached thereto.

The coating chamber 10 is preferably rectangular in shape and comprises a bottom wall 12, a top wall 13, opposite end walls 14 and 15 and side walls (not shown), all walls of which are sealed together to provide an airtight chamber.

The cathode 11 comprises an elongate tubular part 16 axially shaped for sputter coating of non-planar substrates S. As shown in the drawing, the tubular portion is substantially barrel-shaped in shape and is formed with a relatively wide central portion 17 that coincides with the tapered end portions 18 and 19. A coating 20 of selected sputtering agent is applied to the outer surface of the tubular portion.

The vacuum pump 21 is arranged to remove gas from the coating chamber 10 to the desired pressure. If it is desired to inject gases into the chamber, this can be done through a line 22 which is controlled by a valve 23.

The tubular member 16 is supported horizontally at its opposite ends by flanges 24 and 25 formed to join the shafts 26 and 27, respectively. The tubular member may be secured to the flanges 24 and 25 by screws 28 and 29, respectively. The shafts 26 and 27 are rotatably attached to bearing brackets 30 and 31, respectively, which are fixed to the upper wall 13 of the coating chamber by screws 30a. The bearing brackets 30 and 31 are spaced from the top wall 13 of the coating chamber by strips 32 and 33 of insulating material, respectively.

The openings in the bearing brackets 30 and 31 are slightly larger

7991 7 in diameter than the respective shafts 26 and 27, so as to provide relatively loose, annular channels 34 and 35, respectively, which surround said shafts. The annular channels 34 and 35 are closed at opposite sides by bearing seals 36 and 37, said bearing seals also holding the shafts centrally in the openings of the bearing brackets. Insulating sealing rings 40 and 41 are arranged between the flanges 24 and 25 on the shafts 26 and 27 and the bearing brackets 30 and 31, respectively, in order to prevent the coolant introduced into the tubular part from entering the coating chamber.

The shaft 25 is provided with two horizontal ducts 42 and 43 leading from an annular chamber 34 and communicating with the tubular member 16. Formed in the bearing bracket 30 is a short vertical duct 44 leading from the channel 34 to an inlet pipe 45 which is threaded to the bearing bracket. A coolant, such as water, is introduced through pipe 45 and duct 44 into duct 34, from where it flows through ducts 42 and 43 to the tubular portion. The coolant circulates through the tubular portion and exits at its opposite end in the shaft 27 of the horizontal ducts 46 and 47, through the channel 35 and then through the vertical duct 48 in the bearing bracket 31 through the outlet pipe 49.

The tubular member 16 is driven at one end by a motor 50 mounted on the top wall 13 of the coating chamber, said motor being connected via an insulated switch 51 to a vertical shaft 52 to which a helical gear 53 is attached which engages a helical gear 54 on the shaft 26.

The magnetic device 55 comprises a plurality of U-shaped permanent magnets 56 arranged in two straight, parallel rows A and B (Fig. 4) extending longitudinally at the bottom of the tubular portion. The magnets in each row are aligned with the magnets

7991 7 in one row set alternately and overlapping with the magnets in the other row. The magnets in the two rows A and B are also arranged at an angle to each other, as shown in Fig. 4. The outer legs 57 of the magnets 56 in each row of magnets engage a longitudinally extending, relatively narrow strip 58 of suitable magnetic material, while the inner legs of the magnets engage a similar magnetic strip 60 arranged parallel to the strips 58. The permanent magnets attached to the magnetic strips 58 and 60 are shaped longitudinally to correspond to the axial curvature of the tubular portion, and its lower surfaces 63 are shaped to correspond to the transverse curvature of the inner surface of said tubular portion.

The U-shaped magnets 56 are preferably positioned so that the north poles engage the magnetic strip 60. It should be noted, however, that other types of permanent magnets, or even electromagnets, may be used in place of the U-shaped magnets.

The magnets 56 are located close to the inner surface of the tubular portion and are supported by a horizontal rod 64 by suspension straps 65, said rod being supported at its opposite ends by bearing brackets 30 and 31 via shafts 26 and 27.

As mentioned above, the upper surfaces of the substrates S to be coated are shaped to substantially correspond to the longitudinal contour of the tubular part 16. The substrates are held horizontally and moved below the tubular portion to receive the coating material sputtered therefrom by any suitable conveying device, such as rollers 66 and 67 mounted on shafts 68 mounted on bearing supports 69 and 70, in the bottom wall of the coating chamber.

Cathode potential sufficient to cause sput6

7991 7, a tubular portion is supplied from a direct current source (not shown) via a power line 71 connected to an electrical contact 72 having sliding contact with said tubular portion. Device 5 can be grounded in any suitable manner.

It is understood that changes and modifications may be made without departing from the spirit or scope of the appended claims.