Apparatus and method for adjusting rotation angle of magnet system of tubular magnetron
The present invention relates generally to a device and a method for adjusting the rotation angle of a magnet system of a tubular magnetron relative to a support of the tubular magnetron at an end block of the tubular magnetron. The invention also relates to a method for adjusting the rotation angle of the magnet system of such a tubular magnetron.
In the vacuum coating technique, so-called tubular magnetrons are used for sputtering, wherein a tubular target (also referred to as tube target) surrounds a magnet arrangement. Tube targets typically comprise a carrier tube with a target material applied to a side surface or a tube made entirely of a target material.
The tube target is rotatable relative to the magnet structure such that the tube target can be rotated during the coating operation while the magnet structure is uniformly aligned in the coating chamber. By rotating the tube target uniformly under a steady state magnetic field, the entire cylindrical target surface passes through the racetrack area and uniform erosion of the target material is achieved.
Such rotary tube targets are usually mounted in the vacuum chamber of the vacuum coating apparatus between an endblock and a holder, sometimes also between two endblocks, which are designed such that they can enclose the tube target on both sides and hold it with a magnet system inside it, so that the magnet system can be rotated about the axis of the tube target within a defined angular range. The term "rotatable" is distinguishable from "rotation". With regard to angular adjustment, "rotatable" means that the magnet system is mounted such that it can be rotated at least a certain angle in order to adjust its angle. The magnet system does not rotate like a tube target.
The endblock is multifunctional, and in addition to the above, it is used to drive the tube target, power supply, and coolant supply.
To support sputtering, a magnet system of adjacent magnets with locally alternating polarity, also called magnet bars, is arranged in the tube target. Such magnet systems for magnetron sputtering generally comprise a central magnetic pole which surrounds a second opposite magnetic pole in an annular manner. Due to the formation of a tunnel-shaped magnetic field thereby, the target material is removed to a certain extent over the gap between the two magnetic poles, wherein the magnetic field lines extend parallel to the target surface, so that an annular sputtering groove is formed in this region, also called erosion groove form, due to the increase in material removal.
In order to optimize the function of the vacuum coating tube magnetron, the magnet bar angle of the magnet system must be adjusted and changed to the surface to be coated in a targeted and repeatable manner. Solutions are known in which the angle of the magnetic bar is incremented by 15 ° and can be adjusted to an open coating chamber. However, for different applications, these steps are not sufficient to reproducibly create layers with attribute definitions. Precision coatings require nearly infinite adjustability angles over a range of +/-15 deg. or more, with a repetition precision of +/-0.1 deg.. Existing tubular magnetrons do not meet this requirement.
The term repeatedly used herein means a distance that the approaching positions spread apart from each other when repeatedly approaching the target position from one and the same starting position.
Based on the above-mentioned prior art, it is an object of the present invention to improve the adjustability of the angle of rotation of a magnet system, in particular to reduce the adjustable step size, preferably less than 1 °. The repetition accuracy should be ensured at least to a known extent.
An apparatus for this purpose is possible which requires only little technical effort and maintenance.
Further alternatively, the magnet system is rotated without opening the vacuum chamber.
The basic concept of the invention will be described as using a two-part movable rotation angle scale, in this case a rotatable scale, which is rotated by their mechanical connection to the rotating magnetic system of the magnet system. The use of a two-part scale is also suitable for achieving the desired step size by a suitable scale of the first and/or second rotational angle scale. Furthermore, the desired repeatability can be achieved by choosing the appropriate locking means in combination with the design of the scale.
A device with a two-part rotation angle scale is provided at one of the two end blocks of the tubular magnetron and has a flange-like structure due to the rotatable support, and the magnet system is regularly arranged in the tube. It is referred to herein as a flange unit. The flange unit may be arranged in the tube target and may close the tube in which the magnet system is arranged at one side thereof. Alternative configurations depend, for example, on the design of the tubular magnetron, the available installation space or the angular range over which the magnet system can be adjusted.
Features for implementing this concept will be described below. These will be combined with each other in various embodiments in different ways from each other to the extent that they are meaningful and suitable for the application.
One feature is the use of a scale having at least two sections, a main scale having a first angle of rotation scale and a first cursor having a second angle of rotation. It describes a distinction between the terms "scale" and "scale" or "rotational angle scale" of the physical components of the device, where "scale" or "rotational angle scale" denotes, for example, a rotational angle, which applies to the description of the rotational angle of the scale.
Typically, the rotation angle scale is divided symmetrically. Starting from the center zero mark, the same scale extends in both clockwise and counterclockwise directions, which are used with a positive sign in one direction and a negative sign in the other direction. Alternatively, other rotational angle scales may be used. The description will be made with examples mentioned later. The subdivision of the rotational angle scale is referred to as "scale portion" in the following, since the term "scale line" does not always coincide with the actual realization of the scale portion. The order of the scale division is "scale division".
The term "cursor" denotes a rotatable scale relative to the main scale. According to the invention, at least one cursor is arranged, which is designated for distinguishing as "first cursor". Optionally, at least one further cursor can be arranged, which is likewise rotatable relative to the main scale. In this way, the third rotation angle scale can be formed. This can be applied to either the first cursor or the second cursor. In the first case, the further cursor can be realized by the same disc formed by the first cursor. In this case, the further cursor can be a scale of an additional rotation angle parallel to the further rotation angle scale on the same disc, i.e. the second rotation angle scale. In the second case, the further cursor can be realized by a separate disc with its own rotation angle scale, which is arranged concentrically to the first cursor. For greater clarity, the invention will be described below with reference to only one cursor. Their properties and implementations can be similarly applied to other cursors.
The following main scales and cursors are formed as circular, ring-shaped or disk-like discs and are arranged concentrically and adjacent to each other. This means that there is a gap between the two disks or that the two disks are directly adjacent to each other.
The position where the main scale and the cursor are adjacent to each other can be formed, for example, by the orientation of the layers on top of each other based on their common axis.
The side-by-side position of the main scale and the cursor combined with the concentric common axis arrangement can be achieved by forming two annular discs of the vernier scale or large scale, the outer radius of one disc being slightly smaller than the inner radius of the other disc. Thus, two discs can be placed side by side in one plane. Alternatively, one of the two disks may be formed in a ring shape, and the other disk has a thickness deviation, into which the ring-shaped disk may be inserted. Other alternatives to adjacent discs are possible.
The rotation angle scales of the main scale and the vernier may be variously implemented and positioned according to their designs. For example, it can be applied on the circumference, i.e. on the outer edge of the disk or a semicircular arc extending parallel thereto and/or on the lateral surfaces of the main dial and the vernier. It is clear that the rotation angle graduations are arranged and formed such that both rotation angle graduations are visible in the specific case. This can be achieved, for example, by openings in the upper part of the two scales. In the case of congruent disks, the arrangement of at least one rotation angle takes place, for example, on the side surface of one disk or below an opening in the top disk. Alternatively, the main scale and the cursor may not coincide. For example, the latter can be achieved by: the upper outer radius of the two discs is smaller than the outer radius of the lower disc so that the two discs can be placed one above the other and the angle of rotation of the lower disc is still visible. Alternatively, the main scale and the vernier may be formed as adjacent annular discs.
Furthermore, the main scale and the cursor can be rotated relative to one another, the rotation angles moving relative to one another and being set in opposition to different scale values as a result of the rotation of the cursor.
The two rotation angle scales then have different scale divisions which are adapted to the angle range to be set and the step length of the rotation angle adjustment. The scale of the main scale thus covers the entire angular range, e.g. from a position of 0 deg. (e.g. vertical position), 30 deg. clockwise and conversely (+/-30 deg.) from the central axis of the magnet system. The cursor graduation of the cursor has a step size, also referred to herein as cursor step size, which is calculated from the step size of the main scale, also referred to herein as main step size, plus the required subdivision of the main step size. For example, a main step of 1 ° and a vernier step of 1.1 °, results in an increase of the magnet system by 0.1 °. Since each rotation of the cursor will add an additional increment of 0.1 deg. to the previous value. The set angle is generated by two scale portions of the first and second rotation angle scales, which are located just above or opposite each other. Any other angular range and increment or subdivision in degrees, minutes or seconds is possible, adapted to the respective requirements of the tubular magnetron due to the current coating task.
In order to achieve a rotation of the magnet system by means of the above-mentioned flange unit, the vernier scale is designed as a rotatable scale, wherein the magnet system and the main scale are non-rotatable (i.e. static) scales. The static scale is mechanically connected to the static part of the tubular magnetron by suitable connection means. According to another embodiment of a suitable connection means, the pin is mounted concentrically on the main scale and/or the first cursor with respect to its common axis. The connection is considered mechanical to separate it from the electrical connection area and includes both removable and non-removable connections. This connection is used to clamp the magnet system by rotation of the cursor. As a connecting means, a skilled person can use sufficient alternatives to achieve a permanent static and rotational connection.
Furthermore, the flange unit comprises means for locking, with which the angle of rotation of the cursor is fixed in a set angular position relative to the main scale. Alternatively, the locking means may use a form fit or friction connection with the main scale and the cursor or directly between them or a combination of connection types. The frictional connection can be achieved, for example, by pressing together or by magnetic supports of the two discs. For example, a form-fit connection can be formed by terminals, pins or the like, which engage on the main scale and the cursor. The latter defines the position of the main scale and the cursor that are well defined with respect to each other and, depending on the tolerances of the locking device, allows a very high repeatability. For many applications a repetition accuracy of 0.1 deg. is acceptable, but lower values, e.g. a repetition accuracy of 0.5 deg., may also be achieved.
According to one embodiment, the positive-locking connection can be produced by at least one rotation angle index, preferably the rotation angle index or both rotation angle indices of the first cursor, having or being formed by a groove associated with the index, and the locking means being designed to engage in the groove. The groove may be a hole or a channel, a half hole at the edge of the scale, a surface groove or similar groove, shaped such that the locking means engages in the groove to provide a sufficient contact surface. For example, the protruding holes from the side surfaces are adapted to fix the annular disks adjacent to each other. In this case, the outer disc extends through the ring extension channel and the inner disc is parallel to the surface, e.g. a hole with a corresponding channel. It is obvious and usual that the geometries of the main scale and the cursor groove and the locking means are adapted to each other, in particular in such a way that the locking means fixes the cursor relative to the main scale.
In a further embodiment, the flange unit has a reading mark which is designed to indicate the angle value set with the cursor, optionally also with two cursors. This facility of angle reading is advantageous if one or more rotation angle scales are formed by grooves or rotation angle adjustment takes place in a closed coating chamber. The reading marks can be rotated about a common axis on which the main scale and the cursor are concentrically arranged and about which the cursor can be rotated. In this way, the superimposed or relative scale portions of the two rotational angle scales can be marked by reading the markings, and repeatability can be improved.
In one embodiment of the flange unit, the flange unit has a reading mark on which the locking device can be arranged. In this way, the reading mark can be set to a set rotation angle while being locked, for example, the locking means is a pin, a projection, a spring, or the like.
Alternatively, the cursor may comprise an auxiliary rotation angle scale that has been improved, e.g. a scale extension of the second rotation angle scale indicates that an improved angular adjustment is allowed, in particular at very small angular steps. Optionally, the locking device can also influence the auxiliary rotation angle scale, so that the repeatability can also be improved.
The main scale and the cursor are formed as circular, annular or circular segment-like discs and are both connected to two different parts of the tubular magnetron. In order to permanently fix the position of the two scales with respect to each other, the main scale and the cursor can be held by a ring segment or a circular arc segment which is mounted on one of the main scale or the first cursor and which covers the two parts in segments. This design supports the use of the main dial and/or the vernier disk surface to arrange and implement the rotational angle scale as previously described. It also avoids the use of a common concentric shaft, so that the axial passage through the two disks remains free to feed and/or cool the magnet system.
The tubular magnetron according to the invention comprises a tube target, a magnet system provided in the tube target for forming an erosion track on the target surface, a rotatably mounted target shaft for holding and rotating the tube target, and a nozzle arranged in the target shaft for holding the magnet system, as described in more detail above for the prior art. The nozzle holds the magnet system in place within the tube target and cannot rotate, and is therefore stationary relative to the coating chamber around it.
The rotation of the magnet system for adjusting the angle of the magnet system for a defined coating task is achieved by means of a flange unit, which has already been described in detail above, as well as various configurations thereof. To achieve a rotation of the magnet system relative to the tube target and thus relative to the coating chamber and the substrate, the main scale of the flange unit with nozzle and cursor is mechanically connected to the magnet system.
The nozzle is arranged in the target shaft, so that it is suitable for holding the flange unit and the associated magnet system. This arrangement of the flange unit and its support prevents the flange unit from being exposed to the coating material, so that the associated frequent maintenance can be avoided and maintenance of uncoated plant parts reduced.
According to one embodiment, further comprising a drive for moving one of the following: a first cursor, a second cursor (if present), or a locking device. The movement in the case of the first and second cursors described above is a rotation around a desired defined angle. The movement of the locking means depends on its embodiment and may be a rotational or a translational movement or a combination of both. For example, when a pin or spring is used for locking, which engages in a groove on the main scale and/or the cursor, a translational movement is required. For the drive for achieving such a movement, the skilled person can use various options, such as various motors or magnetic units that trigger a translational movement by activating and deactivating the magnetic field.
The angular adjustment of the magnet system of the tubular magnetron with the above-described flange unit is achieved by first rotating the cursor until the central zero mark of its scale division is opposite to the scale portion of the rotation angle scale of the main scale, which is as close as possible to the angle to be set, also referred to as the desired angle. What results from the adjustability should be the scale portion of the main scale to the set angle, which is provided by the cursor. This is produced by the amount of the angle determined by each of the two half-turn scales of the cursor, i.e. the clockwise or counterclockwise scale portions on either side of the zero mark are adjustable.
For example, if the cursor's cursor angle of rotation scale has a 0.1 ° scale and fifteen scales on either side of the zero marking, the cursor can be set to +/-1.5 °, i.e., the angular adjustability is 1.5 ° for each half angle of rotation scale. Therefore, if the angle to be set is +10.5 °, the zero mark of the cursor is set to, for example, +9 ° or +10 ° of the main scale.
Thereby, the cursor in the positive direction is further rotated by fifteen scale sections and previously set to 9 °. If the first setting is 10 deg., then the second rotation has only five divisions.
Alternatively, it is also possible to combine the rotation of the cursor in positive and negative directions, so that the angle to be set is determined by simply adding the rotation angles of the main scale and the cursor, while taking into account the sign of the corresponding half-turn scale.
If multiple cursors are arranged, this method step initially involves the first cursor. Any other cursor for further subdividing the rotation angle of the previous cursor is applied in the same way as described for the first cursor in terms of angular adjustment, wherein the rotation angle scale instead of the main scale is based on the rotation angle scale of the previous cursor.
After the rotation angle is adjusted, each cursor for the angle adjustment as described above is fixed by the burring unit locking means on the main scale, thereby locking the adjustment. By virtue of the mechanical connection of the main scales, the static component of the tubular magnetron and the cursor of the magnet system are fixed to the latter with respect to the tubular magnetron.
According to various embodiments of the method, the locking may be accomplished by reading the indicia. It is utilized to set the reading mark to a position where the main scale and the scale portion of the vernier oppose each other, thereby increasing the target angle. If at least one, preferably all, of the rotation angle graduations has or is formed by a groove associated with the graduation and the locking means are designed to engage in the groove, these grooves can serve both as graduation and as fixing of the graduation.
The above described flange unit of a tubular magnetron, tubular magnetron and method that can be implemented therewith, make it possible to achieve angular adjustability in increments of maximum 0.1 ° of a magnet system that is repeatable by at least +/-0.1 ° and +/-0.05 °, which also takes into account the generally limited spatial conditions on and within the tubular magnetron. The scale difference of the main scale and the vernier rotary scale determines the repetition precision and can be realized according to requirements. If more than two scales are used, the third scale can be used as another cursor relative to the first cursor, which is used as the main scale in this phase. Finally, the step size and repeatability can be further improved.
The present invention will be explained in more detail with reference to examples. Is shown in the attached drawings
FIGS. 1A and 1B are perspective and cross-sectional views of an embodiment of a flange unit of a first increment of an angle adjuster;
FIGS. 2A to 2C are perspective, sectional and enlarged details of another embodiment of an angularly adjusted flange unit having a second step; and
fig. 3 shows an end-block of a tubular magnetron with a flange unit.
The figures only schematically show the apparatus within the scope necessary for explaining the invention. It does not require completeness or scale.
In fig. 1A, the flange unit 11 is shown with a circular cursor 2, wherein the scale portion 6 is formed by a hole. On the cursor 2 formed by the first disc, which is the first and only one cursor 2, there are six graduated portions 6, respectively starting from two directions, on the circular arc segment of the zero mark 12, the half holes, which are exemplary but not limiting, being formed at intervals of 8 °. On the main scale 1, a second disc, six scale portions 6 are also arranged in the form of half holes, at an interval of 10 °. This results in a step size of 2 ° with a repetition accuracy of 0.1 °.
The different angles are achieved by facing different scale portions 6 of the two rotation angle scales 13 and being fixed in this position by suitable locking means 5, in fig. 1A and 1B by way of example but not limitation spring-loaded pins. The suspension of the pin is achieved by a leaf spring, which also serves as a reading mark 4.
Fig. 1B is a sectional view of the flange unit of fig. 1A, in which two directly overlapping disks of the main scale 1 and the cursor 2 can be seen, which have different diameters and are interconnected by a ring segment 8. As a non-limiting example, the diameter of the cursor 2 is greater than the diameter of the main scale 1. The circular arc segment 8 is mounted on the cursor 2 and its inner circumference covers the outer edge of the main scale 1 so that it can rotate freely.
On the back of the cursor 2, a cursor nozzle 9 is arranged, which can be connected to a magnet system 36 (fig. 3). In front of the main scale 1 there is also arranged a nozzle, called flange nozzle 10, which serves as a connection means for the main scale 1, with a static nozzle 39 (fig. 3) arranged in the target shaft 32 (fig. 3) of the tubular magnetron, and thus assembling the flange unit 11 on the tubular magnetron.
If the step size of the angle adjustment is less than 2 °, further rotational angle scales 13 with further scale divisions can be used in a similar manner. For example, to obtain an angular displacement in increments of 0.1 °, it is possible to arrange the inner scale 6 of the cursor 2 at a distance of 3.1 ° and the outer scale 6 of the main scale 1 at a distance of 3 ° (fig. 2A to 2C). Since the indexing distance of the cursor 2 is 3.1 deg., this embodiment of the flange unit 11 allows repeatable setting of precise angles in 0.1 deg. increments with a repetition accuracy of at least +/-0.1 deg..
Fig. 2A to 2C differ from fig. 1A and 1B in that the auxiliary rotational angle index 14, which is formed by a half-hole in addition to the circular arc segment of the cursor 2, is formed. The auxiliary rotation angle scale 14 has a scale corresponding to the scale of the cursor 2. However, it is designed in the form of a vertical line, so that in combination with the optional marks 7 (e.g. grooves) of the reading marks 4, the reading accuracy can be improved.
Fig. 2B shows a cross section of the flange unit of fig. 2A in a sectional view. Here, an alternative similar embodiment of the main scale 1 and the cursor 2 can be seen, which, together with its flange nozzle 10 and cursor nozzle 9, the reading marks 4 and the pins, serves as a locking device 5. This is also engaged by two opposite half-holes of the main scale 1 and the cursor 2 and fixed with respect to each other.
Fig. 2C shows a top view of the three rotation angle scales, the rotation angle scale 13 of the main scale 1 and the rotation angle scale 13 and the auxiliary rotation angle scale 14 of the cursor 2, and their positions of the scale portions 6 relative to each other.
The fixed arrangement is facilitated by forming the rotation angle scale 13 by means of a recess, e.g. a half hole or a differently shaped opening. The fixing of the angular position can also be done by a spring mounted expanded metal if the hole is replaced by a groove. Suitable labeling of the two rows of holes is of interest. Alternatively, the fixing of the rotational angle scale 13 and the adjustment can also be done in other ways.
Fig. 3 shows the flange unit 11 according to fig. 1A, schematically shown in a mounted state in an end block 30 of a tubular magnetron. The tubular magnetron includes a tube target 31, and the tube target 31 is mounted and operated by an endblock 30 in a coating apparatus (not shown). In the tube target 31, a magnet system 36 for forming an erosion track on the target surface is arranged. The tube target 31 is held and rotated by a rotatably mounted target shaft 32. In the target shaft 32, a nozzle 39 for mounting the magnet system 36 is arranged, as described in more detail above with respect to the prior art. The nozzle 39 holds the magnet system 36 in place within the tube target 31 and cannot rotate and is therefore stationary relative to the surrounding coating chamber.
The flange unit 11 is mechanically connected with its flange nozzle 10 to the nozzle 39 and is thus mounted on the end block 30.
The cursor 2 is connected to the magnet system 36 by means of the cursor nozzle 9. The mechanical connection is to a carrier tube 37 holding the magnet system 36 such that the carrier tube 37 and the magnet system 36 follow each rotation of the cursor 2 around the common axis 40 of the main scale and the cursor 2.
List of reference numerals
1 main scale
2 vernier
4 reading mark
5 locking device
6 scale part
7 labelling
8 ring segment
9 vernier nozzle
10 Flange nozzle
11 Flange unit
12 zero mark
13 rotation angle scale
14 auxiliary rotation angle scale
30 end-block
31 tube target
32 target shaft
35 magnetron
36 magnet system
37 bearing pipe
38 flange unit
39 nozzle
40 axle