Plasma coating system and method for coating a workpiece

Abstract

The invention relates to a device (10) for holding a workpiece (30) in a process chamber. The invention also relates to a coating system (20) and a method for coating a workpiece (30). The object of the invention is to allow accurate adjustment of the height of the position of the workpiece (30) while supporting the workpiece in a safe and stable manner. This is achieved in that the holding device (10) comprises a tray (72) for the workpiece (30), and a first height-adjustable support element (22) and a second height-adjustable support element (48) for the tray (72), wherein each of the support elements (22, 48) comprises at least one first and second limb element (26, 56), and in each case the first and second limb elements (26, 56) are connected to pivot relative to each other about a pivot axis X, Y, the pivot axis X of the first support element (22) being arranged at an angle to the pivot axis Y of the second support element (48).

Description

Technical Field

[0001] The present invention relates to a device for holding a workpiece in a processing chamber. The present invention also relates to a coating system and a method for coating a workpiece. Background Art

[0002] A device for holding a workpiece is used to receive the workpiece such that the workpiece is held in a specific position in a processing chamber. For example, a workpiece can be held in a coating system such as a CVD or PVD system in order to undergo a coating process.

[0003] Devices for holding workpieces are known in various designs of the prior art.

[0004] DE10156615B4 discloses a substrate holding table that includes a tabletop having a scissor mechanism. The substrate holding table can be displaced or rotated in various directions. Summary of the Invention

[0005] The object can be considered to provide a device for holding a workpiece, a coating system, and a method for coating a workpiece, wherein the height of the workpiece position can be precisely adjusted while the workpiece is supported in a firm and stable manner.

[0006] The present invention achieves this object by means of a device for holding a workpiece according to one aspect, a coating system according to another aspect, and a method according to yet another aspect. Advantageous improvements of the present invention are set forth in other aspects.

[0007] The device for holding a workpiece according to the present invention includes: a tray for the workpiece; a height-adjustable first support element and a height-adjustable second support element for the tray, wherein each of the support elements includes at least one first limb element and at least one second limb element, wherein the corresponding first limb element and the corresponding second limb element are coupled to pivot relative to each other about a pivot axis, and wherein the pivot axis of the first support element is arranged at an angle to the pivot axis of the second support element.

[0008] The tray can also be designed differently. For example, the tray can be designed such that the tray provides a region that can receive the workpiece to hold the workpiece in a given position. To ensure a high degree of flexibility such that the tray can hold a large number of different workpieces, for example, the tray can preferably be designed to be substantially planar such that a workpiece-specific holder having a workpiece can be positioned on the tray. In addition, the tray region can also include holding means for the workpiece-specific holder, such as notches or grooves.

[0009] The tray is arranged on a first support element and a second support element. The support elements are designed to be able to hold the tray in a given position in a stable manner. In this regard, the support elements are designed to be height-adjustable in order to allow the tray to change its position in the height direction. The height direction should be understood to refer to the direction of the distance between the tray and the boundary arranged below the tray, such as the floor of the processing chamber. Below, the boundary arranged below the tray will be referred to as the upright surface, but is not limited to a specific embodiment. Generally, in such a case, the height direction is oriented perpendicular to the upright surface, and preferably, the substantially planar tray is also oriented perpendicular to the height direction.

[0010] Each of the two support elements includes a first limb element and a second limb element. The corresponding first limb element and second limb element are used to adjust the height of the corresponding support element. For this purpose, the limb elements are arranged at a variable pivot angle with respect to each other. The change in the pivot angle thus changes the height of the entire support element including the two limb elements. For this purpose, the limb elements can preferably be designed to be rigid. The limb elements are pivotally coupled in the region of the pivot axis, for example pivotally coupled in a common connection section, and the limb elements can move about the pivot axis, preferably independently of each other about the pivot axis, and thus can change the pivot angle. The pivotable coupling enables continuous adjustment of the pivot angle and thus continuous height adjustment. The pivot axis can be defined by a straight line about which the limb elements perform a rotational movement. Additionally, the pivot axis can be designed as a rod element such that the limb elements enclose the rod element in the connection section of the limb elements.

[0011] The first support element and the second support element are positioned relative to each other such that the pivot axis of the first support element is arranged at an angle to the pivot axis of the second support element. The angled arrangement enables the tray to be supported in at least two directions. By means of the support element having the second pivot axis, rotation of the tray, for example about the first pivot axis, can be prevented. The angle can be an acute angle or an obtuse angle. Preferably, the pivot axes are arranged at right angles to each other such that each support element is oriented perpendicular to the movement allowed by the other support element.

[0012] The device for holding a workpiece according to the invention can hold the workpiece in a particularly reliable manner, in a firm and stable manner. The support elements each prevent movement of the tray in some degrees of freedom and thus prevent movement of the workpiece in some degrees of freedom. The angled arrangement of the pivot axes advantageously increases the restriction of movement because the restriction of movement caused by the first support element is superimposed on the restriction of movement caused by the second support element. At the same time, the height adjustability is maintained such that the workpiece, for example in a coating system, can be positioned accordingly inside the processing chamber for a coating method. For example, the height of the tray can then be individually adapted to workpieces of different sizes.

[0013] The height adjustability of the first support element and / or the second support element can be designed differently. According to an advantageous refinement, the first support element and / or the second support element comprises an adjustment element which is designed to change the height of the support element. For this purpose, the adjustment element can, for example, cause movement of the support element. The adjustment element can act on the entire support element or on individual components, such as limb elements. Preferably, the adjustment element can comprise a drive which can be designed as a linear or rotary drive. For example, the rotary drive can be a crank or a motor, and the linear drive can be a push rod or a traction cable, and preferably a spindle drive.

[0014] For height adjustment, for example, the adjustment element can displace the first limb element and the second limb element away from or towards each other, such that the overall height of the support element is changed. In a preferred embodiment, the adjustment element is designed to change the pivot angle between the first limb element and the second limb element. For this purpose, the adjustment element can, for example, be coupled to the first limb element and / or the second limb element in order to pivot the first limb element and / or the second limb element about a pivot axis and thus in order to change the position of the first limb element and the second limb element relative to each other.

[0015] In another advantageous embodiment, the adjustment element is designed to displace the pivot axis transversely to the height direction. The direction oriented transversely to the height direction can be understood as the adjustment direction and can thus preferably be oriented horizontally. Preferably, when the pivot axis moves, the end of the limb element spaced apart from the pivot axis remains substantially stationary in the adjustment direction. More preferably, the end of the limb element is connected to the tray in an articulated manner and particularly preferably also to the upright surface in an articulated manner. As a result, a change in the pivot angle can also cause a change in the angle between the limb element and the tray and / or between the limb element and the upright surface. In this way, the tray can change its height while maintaining its orientation, such that the tray is aligned, for example, parallel to the upright surface.

[0016] In a preferred embodiment, the first support element and / or the second support element comprises at least one axial spring element for exerting a force in the direction of the pivot axis of the first support element and / or the second support element. The axial spring element can preferably be attached to a rod element arranged along the pivot axis. The axial spring element can be designed as a torsion spring, a bending spring, a tension spring or a compression spring, and is preferably a compression spring. As a helical spring, the axial spring element can advantageously be arranged around the rod element. The axial spring element can preferably be arranged to act between the limb element and the rod element, since the axial spring element abuts on the limb element on the one hand and on the first locking element located on the rod element on the other hand. Preferably, the limb element is also clamped between the axial spring element and a second locking element, for example located on the rod element. In this way, the axial spring element can act on the limb element, preferably with the spring force of the axial spring element, in order to reduce the clearance between the limb element and the rod element by means of preloading and to impart inertia to the movement of the limb element by means of additional frictional force. In this way, the stability of the tray can be increased. Furthermore, it may be advantageous for the support element to comprise a plurality of axial spring elements for exerting a force. For example, at least two axial spring elements can act on the limb element in opposite directions and clamp the limb element. Due to the opposing spring action of the plurality of axial spring elements, the clearance between the first limb element and / or the second limb element and the rod element, in particular in the axial direction, can be particularly advantageously reduced.

[0017] In a preferred embodiment, a conical element is arranged around a pivot axis, wherein an axial spring element acts on the conical element. The conical element is preferably arranged between the axial spring element and the limb element such that, on the one hand, the axial spring element acts on the conical element in the axial direction and, on the other hand, the conical element centers the limb element and the rod element relative to each other. The axial spring element can be attached to the rod element in the axial direction adjacent to the conical element and abuts against the conical element. Preferably, the conical element includes a locking notch that receives one end of the axial spring element and thus enables a stable and centered positioning of the axial spring element on the conical element. The limb element can preferably include a conical hole that at least partially receives the conical element in a form-fitting manner such that the limb element and the conical element can abut against each other with as little clearance as possible. In this way, the conical element concentrates the force action of the axial spring element on the limb element, reducing the clearance between the limb element and the rod element in the radial and axial directions to a certain extent. Particularly preferably, in each case, at least two conical elements are arranged between the limb element and an axial spring element such that the conical shapes are oriented mirror-symmetrically relative to each other and the axial spring element and the conical elements exert forces on the limb element from two opposite sides. In addition, preferably, the conical element surrounds the rod element in a tight fit such that friction imparts inertia to the relative movement between the conical element and the rod element.

[0018] According to a preferred refinement, only the first support element includes an adjustment element for adjusting the height of the tray. The second support element can preferably follow the movement defined by the first support element. More preferably, the second support element can include a damping element for damping the movement, for example in order to apply a preload.

[0019] According to an advantageous refinement, the rod element is arranged along the pivot axis, wherein a radial spring element is arranged to act radially between the first limb element and / or the second limb element and the rod element. The radial spring element reduces the clearance between the limb element and the rod element in the radial direction by means of a preload and generates an additional frictional force that results in a higher inertia of the movement of the limb element relative to the rod element. Additionally, the radial spring element reduces. The radial spring element can be designed as a torsion spring, a bending spring, a tension spring or a compression spring, and is preferably a compression spring. The radial spring element can be attached, for example, between the first limb element and / or the second limb element and the rod element. Preferably, the radial spring element is partially or preferably completely arranged in a hole in the limb element. Particularly preferably, in each case, the radial spring element is fitted between the first limb element and the rod element and between the second limb element and the rod element such that a clearance in the radial direction of the entire support element can be additionally avoided.

[0020] In an advantageous exemplary embodiment, the first limb element is forked and has a first forked arm and a second forked arm, wherein the second limb element is engaged between the first forked arm and the second forked arm for coupling with the first limb element. The first limb element may for example comprise a body that extends into at least two forked arms on at least one side. Preferably, each forked arm comprises a hole, wherein the holes are aligned with each other and arranged around the rod element. The forked arms are spaced apart from each other in the axial direction such that the forked arms provide space for the second limb element to be engaged between the forked arms. Preferably, the second limb element further comprises a hole that is arranged around the rod element and is aligned with the holes in the forked arms such that the first limb element and the second limb element are pivotally coupled to each other via the rod element. The second limb element may comprise an extension that is designed such that the extension can be arranged between the forked arms. For this purpose, the width of the extension may for example be adapted to the distance between the forked arms such that the width is preferably at least 95% of the distance, and particularly preferably at least 98% of the distance, whereby the gap between the forked arms and the second limb element is minimized. The forked arms provide for example the advantage that the inclination of the limb elements in the axial direction of the rod element is reduced because the two non-movable forked arms provide support at two spaced-apart positions.

[0021] Particularly preferably, the first limb element and the second limb element have the same shape such that the two limb elements each comprise two forked arms and an extension that is arranged on the respective limb element spaced apart from the forked arms in the axial direction. In this way, the extension of the second limb element can be arranged in an engaged manner between the forked arms of the first limb element, and the extension of the first limb element can be arranged in an engaged manner between the forked arms of the second limb element. In this case, the rod element can be arranged in the holes of the extensions and the forked arms of both limb elements simultaneously such that the first limb element and the second limb element are pivotally coupled at two mutually spaced-apart positions.

[0022] In advantageous further improvements, the tray can be laterally adjusted at least in part in a lateral direction transverse to the height direction. For this purpose, the tray can preferably be divided into sections that can be laterally adjusted at least in part. For example, at least one section can be fixedly attached to the support element, while another section can be designed to be laterally adjustable. The laterally adjustable section can be movably connected to the first support element and / or the second support element or the fixed section. For this purpose, the laterally adjustable section can be mounted, for example, to be displaceable on a track or mounted on rollers. Preferably, the laterally adjustable section is attached to eccentrically mounted rollers that are arranged to engage in a recess such that the rollers rolling in the recess in the lateral direction can move the laterally adjustable section linearly together with the rollers. Preferably, an actuating element designed to adjust the laterally adjustable section is attached to the tray. For example, the actuating element can be a slide that pushes the laterally adjustable section on the track. In addition, the actuating element can be, for example, a crank or a knob that is used to set the movement of the roller or the eccentrically mounted roller. The tray can include a plurality of laterally adjustable sections that can move independently of each other. In this regard, the tray can be laterally adjustable in one or more directions transverse to the height direction such that the tray can achieve individually adaptable positioning of the workpiece, for example, in a processing chamber.

[0023] According to a preferred embodiment, at least the first limb element and the second limb element of the first support element and / or the second support element are made of graphite. The limb elements can be composed of a plurality of sections made of graphite or are preferably formed integrally. Due to the low coefficient of friction of graphite, graphite as a material for the limb elements has a particularly positive effect on the ability of the closely abutting limb elements to move in a sliding manner, thus obviating the need for, for example, lubrication. The low coefficient of friction of graphite is also advantageous for maintaining other components of the device that move relative to each other while in contact with each other. For example, if two components move relative to each other while in contact with each other, one component can be made of graphite while the other component is made of another material, such as stainless steel. Particularly preferably, both components are made of graphite. Thus, in addition to the limb elements, the support element to which the tray that can be pivotally attached and can be laterally moved can also be made of graphite. Similarly, the upright surface pivotally connected to the support element can also be made of graphite. In this way, the surface properties of graphite advantageously improve the pivotability of the support element.

[0024] Components made of graphite can be, for example, pressed from graphite powder into the shape of the component. Preferably, the component is made in one piece from a graphite plate, for example, by milling from a graphite plate.

[0025] In addition, due to the low coefficient of thermal expansion of graphite, the advantages provided by graphite are that the shape of graphite changes only very slightly under the influence of temperature gradients and temperature fluctuations. The holding device can preferably be used in a processing chamber for a coating method, in particular in a processing chamber for a plasma-assisted coating method at a temperature in the high-temperature range. The "high-temperature range" should be understood to mean a temperature range with a temperature higher than 300 °C, preferably higher than 400 °C. In this regard, a uniform temperature can exist throughout the processing chamber. For example, preferably, a temperature gradient exists between the immediate surroundings of the workpiece and the floor of the processing chamber. The temperature gradient can be, for example, between the temperature from the high-temperature range and the room temperature to which the holding device is exposed. Similarly, if, for example, the holding device is used for a large number of coating processes carried out at high temperatures, the holding device may be subject to a large number of large temperature fluctuations. If the temperature in the processing chamber decreases between two coating processes and / or if the holding device is removed from the processing chamber, the holding device is subject to large temperature fluctuations.

[0026] The property of graphite having a low coefficient of thermal expansion thus provides the advantage that components made of graphite, such as limb elements, bend only slightly under the influence of temperature gradients and temperature fluctuations. Thus, for example, in the case of a tight fit, the components neither exert pressure on each other nor cause gaps to occur between the components. When used for a large number of coating methods, the low bending and low friction effects have an advantageous effect on the holding device because the risk that the movement of the components is restricted due to wear remains low. Therefore, graphite as a material can be advantageous for the service life of the holding device because even in the case of a coating process with a high number of cycles, the shape of the holding device is only slightly affected.

[0027] A holding device made substantially of graphite is particularly advantageous for carbon-based deposition processes, for example, particularly advantageous for a hot-wire activated CVD coating process because such a holding device has only a small influence on the atmosphere in the processing chamber.

[0028] Therefore, when considered separately, the above aspects of manufacturing the mutually moving components of the holding device for holding a workpiece in a processing chamber using graphite can also prove to be advantageous.

[0029] According to an alternative aspect of the present invention, a device for holding a workpiece in a processing chamber includes a tray for the workpiece and a height-adjustable support element for the tray, wherein the support element includes at least two elements that can move relative to each other and are in contact with each other and are made of graphite. The above advantages resulting from the features of the first aspect of the present invention according to other aspects also apply to this alternative aspect of the present invention.

[0030] In a preferred embodiment, the first support element and / or the second support element further includes a third limb element and a fourth limb element in addition to the first limb element and the second limb element, wherein the third limb element and the fourth limb element are coupled to be pivotable relative to each other about a pivot axis, and wherein the pivot axis of the third limb element and the fourth limb element is arranged parallel to and at a distance from the pivot axis of the first limb element and the second limb element. Preferably, the third limb element is designed in the same manner as the first limb element and the fourth limb element is designed in the same manner as the second limb element. Particularly preferably, all four limb elements have the same shape. In addition, it is preferred that the third limb element and the fourth limb element are arranged in a mirror-symmetrical manner with respect to the first limb element and the second limb element, wherein the plane of symmetry extends parallel to the pivot axis. The support elements can be arranged relative to each other in various ways. For example, the support elements can be arranged adjacent to one another. Preferably, the pivot axes of the support elements form a quadrilateral, particularly preferably a rectangle. Thus, for example, the tray can also be designed as a rectangle and positioned on the support elements such that the support elements are positioned to extend substantially along the sides of the tray.

[0031] The coating system according to the invention comprises: a processing chamber having associated coating means for producing a coating on a workpiece; and a holding device as described above, the holding device being arranged to be adjustable between a first position and a second position, wherein the holding device is arranged inside the processing chamber in the first position and at least partially outside the processing chamber in the second position.

[0032] In this regard, the processing chamber is preferably designed to be hermetically sealable, for example to achieve a vacuum state. For example, the coating means can change the main gas composition, temperature and / or pressure in the processing chamber in order to carry out the coating method. For example, the coating means includes a vacuum pump, one or preferably a plurality of gas suppliers, a heating device, a device for evaporating substances and / or a device for realizing a surface reaction on the workpiece, such as a device for igniting a plasma or for heating the workpiece surface to more than 150 °C. Under these conditions, a coating can be applied to the workpiece, for example to improve the stability, hardness or lifespan of the workpiece. For this purpose, a hard and stable material can preferably be deposited on the workpiece, such as a crystalline material, preferably diamond.

[0033] In the first position, the holding device is located inside the processing chamber. Preferably, the holding device is completely located in and surrounded by the processing chamber such that the holding device is exposed to a defined coating atmosphere. Preferably, the holding device is immovable in the first position such that the tool held by the holding device moves as little as possible.

[0034] In the second position, the holding device is at least partially located outside the processing chamber such that the holding device can be particularly easily equipped with the workpiece to be coated or the coated workpiece can be removed.

[0035] According to a preferred embodiment of the coating system according to the invention, the holding device is displaceably mounted on at least one roller made of graphite for adjustment between a first position and a second position. The roller can be attached below the holding device or on the side of the holding device. For example, the roller can be arranged on a support element. Preferably, a base plate is arranged between the support element and the roller. Particularly preferably, the base plate has the same shape as the tray, for example, a rectangular shape. Mounting the holding device on the roller enables simple and safe displacement between the first position and the second position. In addition, the roller as an adjustment system can be implemented in a simple manner and has few components. Manufacturing the roller from graphite provides the above advantages of graphite for components attached to and movable relative to other components. Particularly preferably, the holding device is mounted on a plurality of rollers, particularly preferably on four rollers, which can be attached, for example, to the four outer corners of a rectangular base plate.

[0036] According to a preferred improvement of the coating system according to the invention, the coating device includes a filament, i.e., a wire, which is designed such that an electric current flows through the filament to heat the filament. Preferably, the filament is designed to reach a temperature higher than 150 °C, particularly preferably higher than 1000 °C. When the filament is close to the surface of the workpiece, the filament heats the surface, preferably to thereby achieve a surface reaction in order to chemically deposit a layer on the workpiece from the gas phase of solid components, particularly preferably to deposit a diamond layer. In addition, the filament is designed, for example, to decompose hydrogen into free radicals, which can then react with a carbon-containing gas to deposit carbon in the form of diamond on the workpiece.

[0037] In order to be able to heat the surface of the workpiece and to activate the hydrogen close to the surface, the filament is preferably arranged in the processing chamber such that in the first position, the height of the tray can be adjusted relative to the filament. For this purpose, the filament is attached above the tray in the processing chamber such that by adjusting the height of the tray, the filament and the tray can move towards each other or away from each other, so that workpieces of different sizes can be arranged on the tray and at the same time be close to the filament. Preferably, the filament is attached in the processing chamber such that the filament is oriented perpendicular to the tray. Preferably, multiple filaments attached parallel to each other in a plane are located in the processing chamber. Particularly preferably, two planes having filaments are arranged parallel to each other. This attachment of the filaments has proven to be particularly advantageous for heating both sides of workpieces that are dominant in the height range, because the workpiece can be positioned, for example, between the planes of the filaments. Description of the Drawings

[0038] The exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. In the drawings:

[0039] Figure 1 A perspective view of a first exemplary embodiment of a holding device is shown,

[0040] Figure 2 showing Figure 1 an exploded view of the holding device according to

[0041] Figure 3 showing Figure 1 and Figure 2 a perspective view of a support element of the holding device according to

[0042] Figure 4 showing Figures 1 to 3 a perspective view of another support element of the holding device according to

[0043] Figure 5 showing Figure 4 a partial cross-section along the section line A..A' in

[0044] Figure 6 showing Figure 4 a cross-sectional view of a limb element along the section line A..A' in

[0045] Figure 7 、 Figure 8 A partial schematic representation of a coating system having a holding device according to Figures 1 to 6 is shown in a front view and a side view. Detailed Description of the Embodiment

[0046] Figure 1 A first exemplary embodiment of a device 10 for holding a workpiece is shown, which device is hereinafter referred to as the holding device 10. The holding device 10 includes a lower structure 12, a first support element 22 that is height-adjustable, a second support element 48 that is height-adjustable, and a tray 72.

[0047] The support elements 22, 48 that support the tray 72 are fastened to the lower structure 12.

[0048] Figure 2 showing Figure 1 the holding device 10 in

[0049] The lower structure 12 includes a base plate 14 and four rollers 16. The base plate 14 is a rectangular planar graphite plate having two longitudinal sides and two short sides. Three metal fastening blocks 18a, 18b are mounted on the upper side of the base plate at two short sides and at the center for mounting the rollers 16 and the support elements 22, 48. The four rollers 16 are connected to be rotatable and are paired with each other by means of shafts for this purpose. In each case, one shaft is attached in the fastening block 18a located on the short side of the base plate 14.

[0050] The first support element 22 includes two longitudinal support units 24 designed to be mirror-symmetrical, wherein one longitudinal support unit 24 is shown in Figure 4 and the longitudinal support unit 24 includes two longitudinal limb elements 26 and a rod element 34.

[0051] The longitudinal limb elements 26 are each cut from a rectangular graphite plate such that the longitudinal limb elements 26 have extensions on their longitudinal sides. Two fork-shaped extensions 28a are positioned close together to form a fork. A single extension 32a is arranged at a distance from the fork on the same long side.

[0052] In each case, the two longitudinal limb elements 26 are joined by a rod element 34 because: in each case, a single extension 32a engages between the fork-shaped extensions 28a, and the rod element 34 extends in the holes of the extensions 28a, 32a that are aligned through the two longitudinal limb elements 26. In this way, the two longitudinal limb elements 26 are joined to be pivotable about the longitudinal pivot axis X because the two longitudinal limb elements 26 are connected to each other in an articulated manner by the rod element 34 arranged along the longitudinal pivot axis X, such that the angle between the two longitudinal limb elements 26 can be changed.

[0053] Two longitudinal fastening shafts 36 extend through the outer longitudinal sides of the two longitudinal support units 24 for pivotably attaching the first support element 22 to the lower structure 12 and the tray 72.

[0054] An axial clamping unit 37 is attached to the rod element 34 and the longitudinal fastening shaft 36, and for each axial clamping unit in the axial clamping unit 37, the cone 44, the axial spring 38, and the locking ring 46 are coordinated. The axial clamping unit 37 is attached to the rod element 34 on the two outer sides of the two forks (see Figure 4 ), and on the other hand, is attached to the longitudinal fastening shaft 36 on the outer side of the longitudinal limb element 26 (see Figure 2 ). The axial clamping unit 37 preloads the articulated connection portion of the longitudinal limb elements on the rod element 34 and on the longitudinal fastening shaft 36 in the axial direction.

[0055] The second support element 48 includes two lateral support units 52 designed to be mirror-symmetrical, and an adjustment element 54. In this regard, Figure 3 A part of the lateral support unit 52 and the adjustment element 54 connected to the lateral support unit 52 are shown. The adjustment element 54 is designed to be symmetrical and the second lateral support unit 52 is attached to the adjustment element 54 in a mirror-symmetrical manner. Each of the lateral support units 52 includes two lateral limb elements 56, which are identical and are also provided as graphite plates. Similar to the longitudinal limb elements 26, two fork-shaped extensions 28b and a single extension 32b are located on the longitudinal sides of the lateral limb elements 56.

[0056] Two screws 58 are attached along the lateral pivot axis Y in a manner spaced apart from each other in the axial direction such that: in each case, the two fork-shaped extensions 28b are pivotally coupled to a single extension 32b via one screw 58.

[0057] The adjustment element 54 is designed as a spindle and includes a spindle thread 64 on each of the two sides, which in each case engages with a threaded nut 66. Additionally, a coupling element 68 (see Figure 2 ) is located on one side of the adjustment element 54 to rotate the spindle 54, for example, with a wrench.

[0058] The threaded nut 66 is coupled to the lateral support unit 52 because the threaded nut 66 is arranged between the two forks of the lateral support unit 52 and is screwed from both sides by means of the screws 58. The threaded nut 66 is located on the lateral pivot axis Y such that the threaded nut 66 is thereby transversely bisected by the pivot axis Y and the axis of the adjustment element 54 is aligned perpendicular to the axis Y. One of the two threaded nuts 66 includes a clockwise thread and the other threaded nut includes a counterclockwise thread such that the movements of the two threaded nuts 66 are opposite during the rotation of the adjustment element 54 and the two threaded nuts 66 move towards each other or move away from each other.

[0059] Two lateral fastening rods 62 extend through the outer longitudinal sides of the two lateral support units 24 for pivotally attaching the second support element 48 to the substructure 12 and the tray 72.

[0060] The tray 72 includes a fastening unit 74, an actuation unit 76, and a support unit 78. The support unit 78 is located on top of the fastening unit 74 and the support unit 78 and the fastening unit 74 enclose the actuation unit 76 within them.

[0061] The fastening unit 74 includes a flat rectangular fastening plate 82 made of a graphite plate. The fastening plate 82 includes three elongated recesses 84 extending parallel to its longitudinal sides. On the lower side of the fastening plate 82, similar to the base plate 14, two fastening blocks 18a are located on the short sides, and one fastening block 18b is located in the center of the fastening plate 82.

[0062] The actuating unit 76 includes three identical eccentric rods 86, and in each case, an eccentric 88 is attached to each end of the eccentric rod 86. All six eccentrics 88 also have the same shape.

[0063] The supporting unit 78 consists of three separate flat rectangular supporting plates 92, which are also made of graphite plates and have recesses (not shown) in the longitudinal direction on their lower sides. On all three supporting plates 92, there are a plurality of ridges to form guiding grooves 94 in the longitudinal direction.

[0064] The actuating unit 76 is located in the recesses of the fastening unit 84 and the supporting unit 78 such that the eccentric rods 86 can rotate and the eccentrics 88 can perform rotational and linear movements. In each case, one supporting plate 92 is located on one eccentric rod 86 having two eccentrics 88, such that the eccentric rod 86 and the eccentrics 88 are inside the recess of the supporting plate 92. The rotation of one of the eccentric rods 86 can thus adjust the supporting plate 92 resting on the eccentric rod 86 relative to the fastening plate 82 in the transverse direction.

[0065] The substructure 12, the two supporting elements 22, 48 and the tray 72 are interconnected via longitudinal fastening rods 36 and transverse fastening rods 62, and the transverse fastening rods 62 and the longitudinal fastening rods 36 are rotatably mounted in the fastening blocks 18a, 18b (see Figure 1 ). For the two longitudinal supporting units 24 and the two transverse supporting units 52, in each case, one longitudinal fastening shaft 36 and one transverse fastening rod 62 are respectively attached in a hinged manner to the fastening blocks 18a, 18b on the base plate 14 and to the fastening blocks 18a, 18b on the fastening plate 82.

[0066] The tray 72 aligned parallel to the substructure 12 can be adjusted in height by means of the second supporting element 48. For this purpose, the height of the tray 72 is adjusted by means of the adjusting element 54 such that the distance between the substructure 12 and the tray 72 is changed.

[0067] The height adjustability of the second element 48 is achieved by means of an elbow joint. Three axes, namely the transverse pivot axis Y and two transverse fastening rods 62, are interconnected in an articulated manner via a transverse limb element 56. The transverse limb elements 56 are joined to each other and to the adjusting element 54 on the transverse pivot axis Y such that the adjusting element 54 can shift the transverse pivot axis Y translationally transversely to the direction of height adjustment and can thus bend or extend the articulated joints of the transverse limb elements 56. In this way, the substructure 12 and the tray 12 remain aligned and parallel to each other during height adjustment.

[0068] Figure 5 A cross-sectional view of one of the two longitudinal limb elements 26 having an axial clamping unit 37 is shown. The cone 44 includes a hole that is adapted to the rod element 34 such that the cone 44 abuts tightly around the rod element 34. In addition, the conical section of the cone 44 is located in a similarly conical material recess of the longitudinal limb element 26 in a form-fitting manner such that the cone is partially surrounded by the longitudinal limb element. On the outside of the longitudinal limb element 26, the cone 44 includes a notch in cross-section in which the axial spring 38 is received in order to hold the axial spring 38 and thus ensure optimal force transmission from the axial spring 38 to the longitudinal limb element 26. The other end of the axial spring 38 is held by an immovable locking ring 46. The axial spring 38 is preloaded between the cone 44 and the locking ring 46 such that the axial spring 38 exerts a force in the direction of the axis X. Two axial clamping units 37 clamp the fork-shaped member on both sides and center the rod element 34 in the hole of the longitudinal limb element 26 (see Figure 4 ). In this way, the clearance of the longitudinal limb element 26, particularly in the direction of the axis X, is reduced, and the friction at the joint formed by the two longitudinal limb elements 26 is increased, such that the movement inertia of the longitudinal limb element 26 is increased.

[0069] Figure 6 The arrangement of the radial spring 42 inside the longitudinal limb element 26 is shown, more specifically the arrangement of the radial spring 42 in a single extension 32a. The radial spring 42 is attached in a hole oriented perpendicular to the axis X and thus acts between the longitudinal limb element 26 and the rod element 34. Since the radial spring 42 is preloaded, the radial spring 42 also reduces the clearance and increases the friction. For the longitudinal support unit 24, the radial spring 42 is installed in the two longitudinal limb elements 26 such that the radial spring 42 acts on the rod element 34 from opposite directions.

[0070] The radial spring 42 is also inserted in the same manner into a single extension 32a of the second support element 48 (not shown).

[0071] The first support element 22 has no height adjustment effect on the holding device 10, but only has a supporting effect along the longitudinal side of the tray 72. In addition to its height adjustment effect, the second support element 48 also has a supporting effect along the transverse side of the tray 72. Therefore, the supporting forces are oriented at right angles to each other and increase the range in the direction of gap reduction. The spacing between the longitudinal support units 24 and between the transverse support units 52 and the damping of the movement of the first support element 22 result in stable holding of the tray 72 without wobbling.

[0072] Figure 7 and Figure 8 Schematically shows how the holding device 10 can be used in the coating system 20.

[0073] The coating system 20 is designed for a hot-wire activated CVD coating process. The filaments 96 are attached in two mutually parallel planes and are aligned perpendicular to the tray 72.

[0074] Figure 7 Shows a row of workpieces 30 held between the two planes of the filaments 96 by the holding device 10. The guide grooves 94 hold the workpiece holders, in which the workpieces 30 are firmly in an upright position. Due to the above-mentioned height and lateral adjustability, the workpieces 30 can be precisely positioned so that the workpieces 30 are precisely arranged between the two planes and are subjected to a local high temperature of, for example, 600 °C locally generated by the filaments. The workpieces can also be arranged on other support plates 92.

[0075] To mount the workpieces 30 on the holding device 10 or to remove the workpieces 30 after the coating process, the holding device 10 is in the fitting position and for this purpose rolls off the coating system 20 on the pull-off base. To coat the workpieces 30, the holding device 10 is completely rolled into the interior of the coating system 20 and is in the coating position. The pull-off base is also pushed in. Due to the arrangement of the support elements 22, 48 and the preloading of the articulated connections, the switching between the fitting position and the coating position takes place with movements involving little clearance.

[0076] List of reference numerals

[0077] 10 Holding device

[0078] 12 Substructure

[0079] 14 Base plate

[0080] 16 Roller

[0081] 18a, 18b Fastening blocks

[0082] 20 Coating system

[0083] 22 First support element

[0084] 24 Longitudinal support unit

[0085] 26 Longitudinal limb element

[0086] 28a Forked extension of the first support element

[0087] 28b Forked extension of the second support element

[0088] 30 Workpiece

[0089] 32a Single extension of the first support element

[0090] 32b Forked extension of the second support element

[0091] 34 Rod element

[0092] 36 Longitudinal fastening axis

[0093] 37 Axial clamping unit

[0094] 38 Axial spring

[0095] 42 Radial spring

[0096] 44 Tapered piece

[0097] 46 Locking ring

[0098] 48 Second support element

[0099] 52 Transverse support unit

[0100] 54 Adjusting element

[0101] 56 Transverse limb element

[0102] 58 Screw

[0103] 62 Transverse fastening rod

[0104] 64 Spindle thread

[0105] 66 Threaded nut

[0106] 68 Connecting element

[0107] 72 Tray

[0108] 74 Fastening unit

[0109] 76 Actuating unit

[0110] 78 Support unit

[0111] 82 Fastening plate

[0112] 84 Recess in the fastening plate

[0113] 86 Eccentric rod

[0114] 88 Eccentric part

[0115] 92 Support plate

[0116] 94 Guide groove

[0117] 96 Filament

[0118] 98 Junction box

[0119] X Longitudinal pivot axis

[0120] Y Transverse pivot axis

Claims

1. A plasma coating system comprising: a treatment chamber having an associated plasma coating device for producing a coating on a workpiece (30), A holding device (10) for holding the workpiece (30) in the processing chamber during a plasma deposition process, the holding device (10) comprising: a tray (72) for the workpiece (30), a first height-adjustable support element (22) and a second height-adjustable support element (48) for the tray (72), wherein each of the support elements (22, 48) comprises at least one first limb element and at least one second limb element, wherein the respective first limb element and the respective second limb element are coupled so as to be pivotable relative to each other about a pivot axis (X, Y), and wherein the pivot axis (X) of the first support element (22) is arranged at an angle to the pivot axis (Y) of the second support element (48), wherein the holding device (10) is arranged to be displaceable between a first position and a second position, and wherein the holding device (10) is arranged inside the process chamber in the first position and is arranged at least partially outside the process chamber in the second position, The first supporting element (22) and / or the second supporting element (48) comprises at least one axial spring (38), which is used to apply a force in the direction of the pivot axis (X, Y) of the first supporting element (22) and / or the second supporting element (48).

2. The plasma coating system according to claim 1, wherein: The first support element (22) and / or the second support element (48) comprises an adjustment element (54) which is designed to change the height of the support elements (22, 48).

3. The plasma coating system according to claim 2, wherein: The adjustment element (54) is designed to change the pivot angle between the first limb element and the second limb element.

4. The plasma coating system according to any one of claims 1 to 3, wherein: A cone (44) is arranged around the pivot axis (X, Y), The axial spring (38) acts on the conical part (44).

5. The plasma coating system according to any one of claims 1 to 3, wherein: A lever element (34) is arranged along the pivot axis, And wherein a radial spring (42) is arranged to act radially between the first limb element and / or the second limb element and the rod element (34).

6. The plasma coating system according to any one of claims 1 to 3, wherein: The first limb element is forked and has a first forked extension and a second forked extension, And wherein the second limb element is engaged between the first forked extension and the second forked extension so as to be coupled with the first limb element.

7. The plasma coating system according to any one of claims 1 to 3, wherein: The tray (72) is at least partially laterally adjustable in a lateral direction transverse to the vertical direction.

8. The plasma coating system according to any one of claims 1 to 3, wherein: At least the first limb element and the second limb element of the first support element (22) and / or the second support element (48) are made of graphite.

9. The plasma coating system according to any one of claims 1 to 3, wherein: The first supporting element (22) and / or the second supporting element (48) comprises a third limb element and a fourth limb element in addition to the first limb element and the second limb element, wherein the third limb element and the fourth limb element are coupled to be pivotable relative to each other about a pivot axis, And wherein the pivot axes of the third limb element and the fourth limb element are arranged parallel to and at a certain distance from the pivot axes (X, Y) of the first limb element and the second limb element.

10. The plasma coating system according to any one of claims 1 to 3, in, The holding device (10) is arranged to be displaceable on at least one roller (16) for displacement between the first position and the second position, And wherein the roller (16) is made of graphite.

11. The plasma coating system according to any one of claims 1 to 3, in, The plasma coating device comprises a filament (96), The filament (96) is arranged in the processing chamber, Such that in the first position, the height of the tray (72) is adjustable relative to the filament (96).

12. A method for coating a workpiece, wherein: The workpiece (30) to be coated is arranged on the tray (72) of the holding device (10) in a treatment chamber of the plasma coating system according to any one of claims 1 to 11, The workpiece (30) is coated by a plasma method when the workpiece (30) is arranged on the tray (72).

13. A holding device (10) for holding a workpiece (30) in a processing chamber during a plasma deposition process, the holding device (10) comprising: a tray (72) for the workpiece (30), a first height-adjustable support element (22) and a second height-adjustable support element (48) for the tray (72), wherein each of the support elements (22, 48) comprises at least one first limb element and at least one second limb element, wherein the respective first limb element and the respective second limb element are coupled so as to be pivotable relative to each other about a pivot axis (X, Y), wherein the pivot axis (X) of the first support element (22) is arranged at an angle to the pivot axis (Y) of the second support element (48), And wherein the first supporting element (22) and / or the second supporting element (48) comprises at least one axial spring (38), which is used to apply a force in the direction of the pivot axis (X, Y) of the first supporting element (22) and / or the second supporting element (48).

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