DE102012211664A1 - Magnetron sputtering device, used to perform vacuum-based physical vapor deposition for coating substrate with target material, includes magnet assembly that concentrates plasma over target surface and comprises hydraulic actuator - Google Patents

Abstract

The magnetron sputtering device comprises a target of material (2) having a surface to be removed, and a magnet assembly for concentrating a plasma over the target surface. The magnet assembly is arranged opposite to a side of the target surface, is moved parallel with respective to the target surface, and comprises a hydraulic actuator and a restoring member. The hydraulic actuator includes a first operating direction, is present in operating connection with the magnet assembly, and is movable in the first operating direction. The restoring member comprises second operating direction. The magnetron sputtering device comprises a target of material (2) having a surface to be removed, and a magnet assembly for concentrating a plasma over the target surface. The magnet assembly is arranged opposite to a side of the target surface, is moved parallel with respective to the target surface, and comprises a hydraulic actuator and a restoring member. The hydraulic actuator includes a first operating direction, is present in operating connection with the magnet assembly, and is movable in the first operating direction. The restoring member comprises second operating direction opposite to the first operating direction, is present operating connection with the hydraulic actuator or the magnet assembly, and is movable in the second operating direction. The restoring member is a further hydraulic actuator. The hydraulic actuators are arranged to each other such that directions of the actuator are perpendicular to each other. The hydraulic actuator is configured as a hydraulic cylinder and as a hydraulic muscle. The magnetron sputtering device further comprises a coolant inlet and a coolant outlet for cooling of the target and the magnet assembly by a cooling agent, and a control valve (8) for controlling a flow rate of a hydraulic fluid to the hydraulic actuator. The inlet and outlet are arranged on a hydraulic fluid port of the hydraulic actuator such that a partial volume of a flow of the coolant is used as the hydraulic fluid for the hydraulic actuator. The control valve is arranged so to the flow of the hydraulic fluid is moved to a first end position of the magnet assembly in first operating direction and the flow of the hydraulic fluid is moved to a second end position of the magnet assembly in the second operating direction. The magnet assembly is movable in the first operating direction.

Description

The invention relates to a magnetron sputtering device.

In the case of magnetron sputtering devices, as used for carrying out a vacuum-based physical vapor deposition, a magnet system is arranged behind the target surface to be ablated, lying electrically on (relative) the cathode potential. As a result of the superimposition of the electric and magnetic fields, the electrons no longer move parallel to the electric field lines but, as a result of the Lorentz force, circle over the target surface (i.e., the cathode) in a closed plasma zone, the so-called racetrack. As a result of the elongated path of the electrons over the target surface, the number and concentration of the ionized atoms of the working gas increases. These high-energy ions are only minimally affected by the magnetic field and accelerated by the electric field to the cathode, where they knock out atoms of the target material, which in turn condense as a layer on the substrate to be coated.

For planar magnetrons (with a flat target) as well as tubular magnetrons (with a hollow cylindrical target), the electron density is greatest at the locations above the target surface where the magnetic field lines are parallel to the target surface. On the other hand, due to the higher ionization, the sputter erosion of the target surface in the immediate area below it is greatest.

In a so-called tubular magnetron, i. a rotatable hollow cylindrical target tube and a magnet system disposed therein, the cathode, and hence the target material, i.e., the target material rotates. the target tube to a stationary magnet system or a movable, for example, rotating magnet system is moved inside the target tube. In order to achieve a closed form of the racetrack, deflection zones of the magnetic field are located at the ends of the target tube. In this region at the end of the target tube, the electrons do not move along the target tube transversely to the direction of rotation of the target, but at one end of the target tube in the direction of rotation (circumferential direction) and at the other end of the target tube opposite to the direction of rotation (circumferential direction). As a result, the target material consumes more rapidly at the ends of the target tube than over the remainder of the target tube, and the resulting typical erosion trenches gain more depth in these end regions (deflection zones) than in the straight ones; parallel to the axis of rotation extending sections of the racetrack.

The lifetime of a target is terminated when the target material has been completely removed at one point of the tube. The result of this is that the removal of the target material in the end regions determines the lifetime of the target, although there would still be sufficient ablatable target material in the areas lying between them.

This disadvantageous effect can not be sufficiently prevented by known design solutions. A defined material increase at the tail end of the target tube (so-called "dog bone" target) is usual in order to counteract the early target failure. In general, this design achieves a longer service life and an acceptable degree of target utilization. The implementation of tube targets in "dog bone" form is generally associated with low added costs for sprayed targets. For cast or ceramic targets, however, the production is more complex and therefore often not economical. Especially with ceramic targets it is known that the joints of the ceramic sleeves attached to one another lead to a formation of traces on the substrate to be coated. To improve target utilization and reduce trace formation, appropriate measures must be taken.

Out DE 10 2011 077 297 a magnetron sputtering device is known, comprising a target and a magnet system, wherein target and magnet system are movable relative to each other and the magnet system forms a target magnetic field for generating a circumferential racetrack. In this case, the magnetic field lines over the surface of the target material in the deflection zones of the racetrack run asymmetrically relative to the normal direction of the target surface, so that the area of the target surface, in which target material is removed above average, shifts with decreasing target thickness during operation of the magnetron sputtering device. Thus, the direction of erosion at the tail ends differs from the normal direction of the target surface. A disadvantage here proves to be in relation to the geometric shape of the target material inflexible and expensive construction of the magnet system.

Out DE 10 2011 004 450 a magnetron sputtering device is known, comprising a hollow target and arranged in the hollow target magnet assembly, wherein the hollow target and the magnet assembly are held at least one side in a holding device, wherein the magnet assembly is attached to a mechanism which upon movement of the hollow target in a movement of the magnet assembly in the longitudinal direction of the hollow target permits. A tracking, In particular, a symmetrical tracking of the magnet arrangement under the target material has the advantage that the target material is consumed more uniformly and a shift of the resulting erosion traces on the target surface is prevented by the tracking. A disadvantage, however, is due to the fixed arrangement of the magnets inflexible design, which can be reacted only insufficiently to change in shape and composition target material.

In US 2011/0155568 A1 It has been proposed to gradually shift the magnet arrangement in a tube target of a rotating sputtering magnetron relative to the tube target by a stepping gear during the rotation of the tube target. For this purpose, the step gear comprises a crank mechanism connected to the magnet arrangement, the connecting rod of which is connected at one end to the magnet arrangement and at the other end to a crank wheel which has recesses distributed over the circumference. With the tube target rotates a pin which engages with each revolution of the tube target in one of the recesses of the crank wheel and this continues to move until the pin disengages from the recess. The crank wheel translates its incremental rotational motion into a stepwise linear motion of the magnet assembly which reciprocates between two end positions along the axis of rotation of the tube target. The discontinuous movement of the magnet system relative to the target improves the uniformity of the target consumption with respect to a fixed magnet arrangement, but nevertheless leads to the erosion trench in each case forming deeper latching lines at the positions at which the crank mechanism stands idle in principle.

The object is therefore to provide a magnetron sputtering device, by means of which an even more homogeneous consumption of the target material and a minimization of the trace formation on the substrate to be coated can be achieved.

The object underlying the invention is achieved by a magnetron sputtering device with the features of the independent claim 1. In the dependent claims advantageous embodiments and developments are described.

A magnetron sputtering device is proposed, comprising a target having target material with a target surface to be ablated, and a magnet assembly for concentrating a plasma above the target surface which is movably disposed on the opposite side of the target surface relative to and parallel to the target surface, the magnet assembly being characterized by at least a hydraulic actuator, which has at least one first direction of action and which is in operative connection with the magnet arrangement, is movable in a first direction of action.

It is expedient that the magnet arrangement can be moved in the second direction of action by at least one return element, which has a second direction of action opposite the first direction of action and which is in operative connection with the at least one hydraulic actuator or the magnet arrangement. It is particularly advantageous that the at least one return element is a further hydraulic actuator. But it can also be used other restoring members such as mechanical spring elements.

Hydraulic actuators are preferably designed as hydraulic cylinders but also as hydraulic muscles, which are pure tension actuators. Hydraulic muscles offer the advantage of smooth and slip-free operation, which leads to a particularly uniform movement of the magnet system and thus also a particularly uniform removal of the target material from the target surface. Due to their particularly simple design, the hermetically sealed construction and the associated longevity, hydraulic muscles are particularly suitable for use in magnetron sputtering devices.

It is also expedient that the at least one hydraulic actuator has a second effective direction opposite the first effective direction and the magnet arrangement is movable in the second effective direction by the at least one hydraulic actuator which is in operative connection with the magnet arrangement. By using double-acting hydraulic actuators, i. of hydraulic actuators with two active directions of movement, for example for a tensile region and a pressure region, the number of hydraulic actuators required for the movement of the magnet system is reduced by half.

It is particularly advantageous that the magnetron sputtering device has at least one coolant inlet and at least one coolant outlet for cooling the target and the magnet arrangement by means of a coolant and at least one hydraulic fluid port of the at least one hydraulic actuator is arranged such that a partial volume flow of the coolant as hydraulic fluid for the at least one hydraulic actuator is used.

In one embodiment of the invention, at least one hydraulic actuator for controlling the volume flow of the hydraulic fluid through the hydraulic actuator to a control valve, wherein the control valve is arranged so that when it reaches the Magnet arrangement in the first end position of the first effective direction, the volume flow of the hydraulic fluid is switched so that the magnet assembly is movable towards the second end position of the second direction of action and that the control valve on reaching the magnet assembly in the second end position of the second direction of action, the volume flow of the hydraulic fluid so, the magnet arrangement is movable towards the first end position of the first direction of action. In addition to this mechanical actuation of the control valve, a control valve can also be provided which is switched by means of an electrical signal of a control unit comprising the magnetron sputtering device. In both the mechanical and electrical actuation of the control valve, the movement of the magnet assembly is independent of the movement of the target. That is, the rotational speed and the rotation direction of the tube target have no influence on the translation speed of the magnet assembly. As a result of this decoupling, it is possible to react flexibly to the target material changing in shape and composition. According to the invention, the trace formation on the target surface is reduced by the continuous and harmonic movement of the magnet arrangement.

For Planarmagnetrons it is expedient that at least two hydraulic actuators are arranged relative to each other so that their directions of action are perpendicular to each other. By an independent control of the effective directions of the hydraulic actuators, it is possible to move the magnet arrangement in any desired manner relative to the target surface.

The invention will be explained in more detail with reference to an embodiment.

In the accompanying drawings shows

1 a cross section through a tube magnetron

The in 1 shown tubular magnetron is part of a Magnetronsputterereinrichtung not shown, wherein the support tube 3 is rotationally connected to the magnetron sputtering device. For holding the magnet carrier 18 , which magnets, not shown, for generating a plasma zone on the target tube 1 opposite side of, on the target tube 1 arranged, target material 2 have, are axially along the axis of rotation 19 of the target tube 1 , which also symmetry axis of the support tube 3 is, a first sliding bearing 4 and a second sliding bearing 5 on the support tube 3 arranged. The first sliding bearing 4 and the second sliding bearing 5 are designed so that the magnetic carrier 18 axially along the axis of rotation 19 is slidably mounted. The target tube 1 rotates with the target material arranged thereon 2 around the axis of rotation 19 and is held by a storage, not shown.

Center of the axial extent of the target tube 1 along the axis of rotation 19 is on the support tube 3 the control valve 8th arranged. With symmetrical alignment of the magnet carrier 18 to the target tube 1 along the axis of rotation 19 are each at the same axial distance to the control valve 8th a first end position 9 and a second end position 10 at the to the support tube 3 facing surface of the magnetic carrier 18 arranged. The geometric extension of the end position 9 and the final position 10 from the to the support tube 3 facing surface of the magnetic carrier 18 towards the support tube 3 is chosen so that one on the control valve 8th attached lever from the end position 9 and the final position 10 is changed in his direction, which also leads to a reversal of the hydraulic fluid in the control valve 8th between the first hydraulic muscle 6 and the second hydraulic muscle 7 leads. With symmetrical alignment of the magnet carrier 18 to the target tube 1 along the axis of rotation 19 are each at the same axial distance to the control valve 8th a first hydraulic actuator bearing 20 and a second hydraulic actuator bearing 21 at the to the support tube 3 facing surface of the magnetic carrier 18 arranged.

The first hydraulic muscle 6 as well as the second hydraulic muscle 7 each have two hydraulic fluid openings. During each hydraulic fluid opening of the first hydraulic muscle 6 and the second hydraulic muscle 7 at the control valve 8th is arranged, then in each case the other hydraulic fluid opening with a first throttle valve 14 for the first hydraulic muscle 6 and a second throttle valve 15 for the second hydraulic muscle 7 connected. On the side of the first hydraulic muscle 6 and the second hydraulic muscle 7 at which the first throttle valve 14 and the second throttle valve 15 are arranged the first hydraulic muscle 6 on the first hydraulic actuator bearing 20 stored and the second hydraulic muscle 7 from the second hydraulic actuator bearing 21 stored, on the other side of the first hydraulic muscle 6 and the second hydraulic muscle 7 These are at the control valve 8th stored.

The target tube 1 as well as the magnetic carrier 18 are cooled by means of cooling liquid. This occurs as a coolant flow 11 at an axial end of the support tube 3 in the interior of the support tube 3 one to at the other axial end of the support tube 3 emanate from this and in the annular space between the carrier tube 3 and target tube 1 as coolant return 12 flow back. From the coolant supply 11 is a partial flow, referred to as hydraulic fluid 13 , before the entrance of the Coolant-forward 11 in the carrier tube 3 taken from a device, not shown, and the pressure of the hydraulic fluid 13 increased by means of a printer, not shown. By means not shown hydraulic lines, the hydraulic fluid passes 13 from the pressure booster to the control valve 8th , In 1 is the control valve 8th adjusted so that it is the way of hydraulic fluid 13 in the first hydraulic muscle 6 releases, so that this expands in its circumferential direction and thereby a contraction movement in the longitudinal direction, along the axis of rotation 19 , which creates the magnet carrier 18 in the first direction of action 16 is moved. During the movement in the first direction of action 16 occurs the hydraulic fluid 13 through the first throttle valve 14 in the coolant return 12 and leaves the annular space between the carrier tube 3 and target tube 1 , Achieve the first end position 9 during the movement of the magnet carrier 18 in the first direction of action 16 the lever of the control valve 8th , so this is actuated and controls the direction of the hydraulic fluid accordingly 13 in the control valve 8th , whereby the second hydraulic muscle expands in its circumferential direction and thereby a contraction movement in the longitudinal direction, along the axis of rotation 19 , which creates the magnet carrier 18 in the second direction of action 17 is moved. During the movement in the second direction of action 17 occurs the hydraulic fluid 13 through the second throttle valve 15 in the coolant return 12 and leaves the annular space between the carrier tube 3 and target tube 1 , Achieve the second end position 10 during the movement of the magnet carrier 18 in the second direction of action 17 the lever of the control valve 8th , so this is actuated and controls the direction of the hydraulic fluid accordingly 13 in the control valve 8th around, which in turn causes a movement in the first direction of action 16 arises. The frequency of the resulting cyclic reciprocation in the first direction of action 16 and the second direction of action 17 on the one hand by the height of the pressure difference between the coolant 11 . 12 and the hydraulic fluid 13 before flowing through the first hydraulic muscle 6 and the second hydraulic muscle 7 and on the other by the pressure losses of the first throttle valve 14 and the second throttle valve 15 certainly. Accordingly, the movement of the magnetic carrier 18 in the first direction of action 16 and second direction of action 17 regardless of the rotation of the target tube 1 around its axis of rotation 19 ,

LIST OF REFERENCE NUMBERS

1

target tube

2

target material

3

support tube

4

first sliding bearing

5

second sliding bearing

6

first hydraulic muscle

7

second hydraulic muscle

8th

control valve

9

first end position

10

second end position

11

Coolant supply

12

Coolant return

13

hydraulic fluid

14

first throttle valve

15

second throttle valve

16

first effective direction

17

second direction of action

18

magnet carrier

19

axis of rotation

20

first hydraulic actuator bearing

21

second hydraulic actuator bearing

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102011077297 [0007]
• DE 102011004450 [0008]
• US 2011/0155568 A1 [0009]

Claims (9)

Magnetron sputtering device comprising a target, the target material ( 2 ) having a target surface to be ablated, and a magnet assembly for concentrating a plasma above the target surface movably disposed on the opposite side of the target surface relative and parallel to the target surface, characterized in that the magnet assembly by at least one hydraulic actuator, the at least one first direction of action ( 16 ) and which is in operative connection with the magnet arrangement, in the first direction of action ( 16 ) is movable. Magnetronsputterereinrichtung according to claim 1, characterized in that the magnet arrangement by at least one return member, one of the first direction of action ( 16 ) opposite second direction of action ( 17 ) and which is in operative connection with the at least one hydraulic actuator or the magnet arrangement, in the second direction of action ( 17 ) is movable. Magnetronsputterereinrichtung according to claim 2, characterized in that the at least one return member is a further hydraulic actuator. Magnetronsputterereinrichtung according to claim 1, characterized in that the at least one hydraulic actuator one of the first direction of action ( 16 ) opposite second direction of action ( 17 ) and the magnet arrangement by the at least one hydraulic actuator, which is in operative connection with the magnet arrangement, in the second direction of action ( 17 ) is movable. Magnetronsputterereinrichtung according to one of claims 1 to 4, characterized in that at least two hydraulic actuators are arranged relative to each other so that their effective directions ( 16 . 17 ) at right angles to each other. Magnetronsputterereinrichtung according to one of claims 1 to 5, characterized in that at least one hydraulic actuator is designed as a hydraulic cylinder. Magnetronsputterereinrichtung according to one of claims 1 to 6, characterized in that at least one hydraulic actuator as a hydraulic muscle ( 6 . 7 ) is executed. Magnetronsputterereinrichtung according to one of claims 1 to 7, characterized in that the Magnetronsputterereinrichtung at least one coolant inlet ( 11 ) and at least one coolant outlet ( 12 ) for cooling the target and the magnet arrangement by means of a coolant and at least one hydraulic fluid port of the at least one hydraulic actuator is arranged such that a partial volume flow of the coolant as hydraulic fluid ( 13 ) is used for the at least one hydraulic actuator. Magnetronsputterereinrichtung according to one of claims 1 to 8, characterized in that the at least one hydraulic actuator for controlling the volume flow of the hydraulic fluid ( 13 ) by the hydraulic actuator a control valve ( 8th ) and the control valve ( 8th ) is arranged so that when it reaches the magnet arrangement in the first end position ( 9 ) of the first direction of action ( 16 ) the volume flow of the hydraulic fluid ( 13 ) so that the magnet arrangement towards the second end position ( 10 ) of the second direction of action is movable and that the control valve ( 8th ) upon reaching the magnet arrangement in the second end position ( 10 ) of the second direction of action ( 17 ) the volume flow of the hydraulic fluid ( 13 ) so that the magnet arrangement towards the first end position ( 9 ) of the first direction of action ( 16 ) is movable.

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