Arc source for homogeneous removal of the target surface

Abstract

The present invention relates to an arc evaporation source, comprising a target (1) to be operated as cathode, comprising material to be evaporated, the target (1) exhibiting a target front surface (10), a target back surface (20) and a target lateral surface (30), where the target lateral surface (30) extends from the border of the target front surface (10) to the border of the target back surface (20) and the distance between the target front surface (10) and the target back surface (20) along a respective perpendicular axis (A-A) corresponds to the target thickness, an electrode as anode (70) having an inner surface for acting as electron receiving surface, a magnetic guidance system comprising means (100) for creating magnetic fields comprising magnetic field lines located in front of the target front surface (10), and confinement means (50) placed at least partially surrounding the target lateral surface (30).

Description

[0001] Arc source for homogeneous removal of the target surface

[0002] The present invention relates to an arc evaporation source and a method for deposition of coating layers using an arc evaporation source, wherein the inventive arc evaporation source allows homogeneous removal of target surface material and stable coating layer deposition of different kind of coating layers, for example of the type metallic layers, nitride layers, oxide layers, carbide layers, oxynitride layers, oxycarbide layers, carbooxynitride layers, carbonitride layers, as well as combinations thereof.

[0003] The present invention is especially suitable for stable deposition of metallic layers and allows even stable deposition of thick metallic layers.

[0004] In the context of the present invention metallic layers (also called metallic coating layers) are coating layers having metallic character, for example coating layers having metallic character because of their chemical element composition.

[0005] Metallic layers in the context of the present invention are not limited to an specific chemical element composition but can have for example a chemical element composition in atomic concentration complying with the formula:

[0006] MeaXl-a, where:

[0007] • a is the atomic concentration of Me and correspond to a value in the range 0.95 < a < 1 , preferably 0.98 < a < 1 , and

[0008] • Me is one or more elements from the chemical elements in the periodic table of elements classified as metal or alkali metal or alkali earth metal or transition metal, or post-transition metal or metalloid, for example in particular comprising (but not limited to) one or more elements from Ti, Cr, Ni, Co, Cr, Al, Y, Zr, Hf, Mo and Ta, and • X is one or more chemical elements different from Me, which are available in the coating as unavoidable impurities, in particular X can be one or more elements from the chemical elements in the periodic table of elements classified as noble gas or nonmetal, for example in particular comprising (but not limited to) one or more elements from C, 0, Ar, Kr.

[0009] In the context of the present invention metallic layers may be considered to be thick metallic layers if they have for example a layer thickness higher than 3 pm, preferably in a range from 5 pm up to 250 pm, more preferably in a range from 10 pm up to 100 pm.

[0010] Prior art

[0011] Many arc evaporation sources are well known from the prior art and are used as coating material sources in physical vapor deposition (PVD) processes of the type arc evaporation.

[0012] For example, in WO 2021 / 001536 A1 an arc evaporation source (in WO 2021 / 001536 A1 also called cathodic arc source or cathodic arc evaporation apparatus) is described, which comprises a target as cathode, an electrically floating confinement located adjacent the side-target surface, and an electrode as anode.

[0013] However, existing arc evaporation technologies do not allow attaining a service life of such arc evaporation sources that is high enough for meeting the current demand in cases in which thick layers, in particular thick metallic layers have to be deposited.

[0014] Existing arc evaporation technologies have furthermore the disadvantage that it is not possible to attain deposition rates of metallic layers that are high enough for enabling a profitable production of thick metallic layers.

[0015] A further disadvantage of using existing arc evaporation technologies for producing thick metallic layers is the high incidence of electrical shorts that often lead to coating process breakdown resulting in higher consume of time and resources as well as lower coating quality, which in turn is economically disadvantageous.

[0016] Objective of the present invention

[0017] The main objective of the present invention is to provide a new arc evaporation source for overcoming the drawbacks of the prior art, in particular the inventive new arc evaporation source should allow carrying out arc evaporation PVD processes that involves the production of metallic layers, inclusive thick metallic layers on substrates to be coated in an efficient manner.

[0018] The new arc evaporation source and method should further allow attaining a high utilization of target material, homogeneous target surface removal, higher service life of the arc evaporation source, high coating layer deposition-rate and in general a more stable and efficient coating process in comparison with the prior art.

[0019] Detailed description of the present invention

[0020] The objective of the present invention is attained by providing an arc evaporation source according to claim 1 as well as a coating device according to claim 17 and an arc evaporation coating method according to claim 19. Preferred embodiments of the invention are disclosed in the dependent claims.

[0021] According to the invention, the arc evaporation source comprises a target to be operated as cathode comprising material to be evaporated, the target exhibiting a target front surface, a target back surface and a target lateral surface, where the target lateral surface extends from the border of the target front surface to the border of the target back surface, and the distance between the target front surface and the target back surface along a respective perpendicular axis corresponds to the target thickness, an electrode as anode having an inner surface for acting as electron receiving surface, a magnetic guidance system comprising means for creating magnetic fields comprising magnetic field lines located in front of the target front surface, and confinement means placed at least partially surrounding the target lateral surface, wherein the confinement means being designed as one or more ring- shaped confinement elements, wherein at least the part of the target lateral surface adjacent to the target front surface is surrounded by the at least one ring-shaped confinement element and the at least one ring-shaped confinement element has an internal diameter with an internal surface and an external diameter with an external surface, wherein the internal diameter is smaller than the external diameter and wherein at least at a position in which the at least one ring-shaped confinement element is placed surrounding the target lateral surface, the internal diameter is variable in a direction that is parallel to the perpendicular axis.

[0022] The term that the internal diameter is variable in a direction that is parallel to the perpendicular axis may preferably be understood to mean a funnel-shaped inner form. In an arc evaporation source, a confinement element with a funnel-shaped internal form, which creates a variable internal diameter offers several distinct advantages in target utilization and coating quality.

[0023] For instance (in a funnel narrowing in the direction of a substrate), an optimized enhanced arc confinement can be realized, because the funnel shape may direct the vaporized material towards the central region of the source. This may improve arc stability by containing the arc more effectively, reducing arc wander, and maintaining a consistent discharge path.

[0024] Moreover (in a funnel enlarging in the direction of a substrate), an increased target material utilization can be realized, because the funnel shape allows a more effective distribution of the arc spots across the target surface. This may help utilize the target material more evenly, reducing the likelihood of creating deep craters or localized erosion on the target. An improved utilization not only extends the target's life but also reduces material costs.

[0025] Additionally, the confinement element’s funnel shape (in a funnel enlarging in the direction of a substrate) helps to distribute the heat load more evenly on the target. By preventing excessive heat buildup in localized areas, this design mitigates thermal stress on the target material, reducing the risk of cracking or other forms of degradation. For effective evaporation of target material at least the target front surface may be made of material to be evaporated.

[0026] In order to guarantee a targeted and controllable evaporation of target material, the confinement means with a confinement height may be arranged in the arc evaporation source in a way that a lateral gap is formed between the target and the confinement means, wherein preferably the lateral gap has a variable diameter.

[0027] With respect to a targeted and controllable evaporation, the internal diameter of the confinement means may change constantly, preferably constantly along its entire confinement height. The continuous change in diameter helps to direct the vapor plume in a controlled manner. It promotes even density distribution across the vapor cloud, improving the uniformity of deposition on the substrate. This smooth variation can reduce the formation of hotspots or low-density areas in the vapor, leading to more uniform and high-quality coatings.

[0028] With respect to a generation of a funnel form of the confinement means enlarging in the direction of a substrate and a realization of the benefits mentioned above, which are combined with this design, the inner diameter of the confinement means may be largest in the area surrounding the target lateral surface.

[0029] With respect to an enhanced arc control and a reduced contamination, it may also be conceivable that the confinement means is located between the target and the anode, preferably completely between the target and the anode. By fully surrounding the target and isolating it from the anode, the confinement element can help to focus the arc spots on the target, reducing arc wandering and improving the consistency of the evaporation process. Moreover, this configuration helps to prevent unwanted particles or contaminants from entering. This can improve the purity of the evaporated material and, in turn, the quality of the deposited coating.

[0030] With respect to a favorable design, the external diameter may be constant or variable in a direction that is parallel to the perpendicular axis. Maintaining a constant external diameter ensures compatibility with standard cooling systems, which can then dissipate heat effectively while the internal funnel shape handles the plasma dynamics. Moreover, with a constant external diameter, the confinement element can integrate seamlessly with existing arc evaporation setups, minimizing system redesign requirements.

[0031] Additionally, with respect to a favorable design, there may be a gap between a point of the internal surface of the at least one ring-shaped confinement element that is closest to the target lateral surface and the lateral surface, wherein preferably the gap may correspond to a distance in a direction that is perpendicular to the perpendicular axis, which may be in particular in a range between 0.5 mm and 5 mm.

[0032] With regard to a targeted, controllable and effective evaporation of target material the at least one ring-shaped confinement element may exhibit a confinement height extending from a target surface level point that is placed at the same level of the target front surface up to an anode level point that is placed at the topmost surface of the at least one ring-shaped confinement element, wherein preferably the confinement height may be the distance between the target surface level point and the anode level point in a direction parallel to the perpendicular axis, wherein in particular the confinement height may be kept constant during the coating process even while the thickness of the target is decreasing.

[0033] Furthermore, regarding an effective evaporation of target material, said means may be designed and adjusted for producing a magnetic field region comprising field lines that are substantially perpendicular to the target front surface, i.e. substantially parallel to the perpendicular axis.

[0034] Advantageously, said confinement height and confinement means may be selected and adjusted in such a manner that sparks are allowed to move at the border line of the target front surface, and if a spark is moving at the border line of the target front surface it may be realized that the spark cannot follow the magnetic field lines to attain the electron receiving surface of the anode but is guided by the magnetic field lines to go outside of the target border line in direction to the means, in order to produce an extinction of the spark and subsequently an increment of a current density in one of the sparks remaining on the target front surface, in order to result in turn in a separation of the spark receiving an increment of current density in two sparks.

[0035] With regard to homogeneous material removal, said confinement height and confinement means may be selected and adjusted in such a manner that a homogeneous motion of the sparks along the complete target front surface is feasible, resulting in an homogeneous remove of target surface material by evaporation.

[0036] Moreover, it has proved to be particularly advantageous, if the target may have a starting thickness of more than 10 mm, preferably a starting thickness between 15 mm and 40 mm, in particular a starting thickness of 20 mm.

[0037] It has also proved to be particularly advantageous, if the target, the magnetic guidance system and the confinement means may be designed to be operated with at least two arc-spots and preferably to allow an arc-spot randomly to move outside the target area and to extinguish.

[0038] Preferably, said gap may correspond to a distance in a range from 1 mm up to 3 mm, in particular to a distance in a range from 1 mm up to 2.5 mm.

[0039] However, the confinement height may be preferably in a range from 2 mm up to 100 mm.

[0040] With regard to the effective generation of a stable and powerful magnetic field, it may advantageously be further provided according to the invention that the means may comprise an electromagnetic coil and a permanent magnet, wherein preferably both may have identically directed north and south poles, and both may be placed in relation to the target in such a manner that the target back surface is in each case closer to the polarity north than to the polarity south of each one of the electromagnetic and the permanent magnet or the target back surface is in each case closer to the polarity south than to the polarity north of each one of the electromagnetic and the permanent magnet. Thus, in other words, the present invention according to a particular preferred embodiment relates in particular to an arc evaporation source, comprising a target to be operated as cathode, confinement means being designed as one or more ring- shaped confinement elements placed at least partially surrounding the target lateral surface, wherein at least the part of the target lateral surface adjacent to the target front surface is surrounded by the at least one ring-shaped confinement element, wherein there is a gap between a point of the internal surface of the at least one ring-shaped confinement element that is closest to the target lateral surface and the lateral surface and the gap corresponds to a distance in a direction that is perpendicular to the target front surface, which is in a range between 0.5 mm and 5 mm, and wherein means are being provided for producing a magnetic field region comprising field lines that are substantially perpendicular to the target front, wherein said the confinement means and magnetic means are selected and adjusted in such a manner that sparks are allowed to move at the border line of the target front surface and guided by the magnetic field lines to go outside of the target border line in direction to the magnetic means, producing in this manner the extinction of any spark going beyond of the target front surface border line and subsequently producing an increment of the current density in at least one of the sparks remaining on the target front surface, which in turn results in a separation of the spark receiving an increment of current density in two or more sparks, this allowing a homogeneous motion of the sparks along the complete target front surface, this resulting in an homogeneous remove of target surface material by evaporation during operation of the inventive arc evaporation source.

[0041] Another object of the invention is a coating device, comprising a vacuum coating chamber, comprising at least one chamber interior wall, wherein an arc evaporation source as described above is fixed at a surface of the chamber interior wall by using fixing means, wherein preferably the fixing means comprise at least a back plate, wherein in particular the fixing means comprise a lateral fixture system.

[0042] Furthermore, another object of the invention is a an arc evaporation coating method, preferably carried out by using an arc evaporation source as described above, wherein the method comprises the steps of: a) Invoking at least a first arc-spot and a second arc-spot at least for a certain time interval running separately both on the front surface of a target, b) Provoking the first arc-spot to divide into two separated arc-spots, thereby forming a third arc-spot and a fourth arc-spot, wherein the division of the first arc-spot into two separated arc-spots is provoked by letting extinguish the second arc-spot.

[0043] Preferably, the extinguishing of the second arc-spot may be reached by allowing the second arc-spot to move beyond the border of the target into an area with a surface which does not allow it to extract electrons from the surface any more.

[0044] In addition, it has proven to be particularly advantageous, if the material of the target may be a MCrAlY material.

[0045] Additionally, it has proven to be advantageous if the method may be performed within a vacuum chamber of a coating device after establishing a vacuum within the vacuum coating chamber.

[0046] In the context of the present invention increasing utilization of target material refers in particular to improvements in relation to following aspects:

[0047] - Increasing the amount of evaporated target material that is evaporated during coating process and is transported from the target surface to the surface of the substrates to be coated that are placed in the interior of the coating chamber, thereby forming metallic layers on the corresponding substrate surfaces;

[0048] - Reducing the amount of evaporated target material that is evaporated during coating process and is not transported from the target surface to the surface of the substrates to be coated that are placed in the interior of the coating chamber, but is transported to surfaces or parts or components that are not substrates to be coated but are also placed in the interior of the coating chamber, thereby forming metallic layers on the surfaces of such parts or components; In the context of the present invention increasing service life of the arc evaporation source refers in particular to improvements in relation to following aspects:

[0049] - Increasing the amount of target material that can be evaporated during coating process, in particular by increasing the target thickness;

[0050] In the context of the present invention increasing deposition rate refers in particular to improvements in relation to following aspects:

[0051] - Allowing faster deposition of thick metallic layers;

[0052] In the context of the present invention attaining a more stable and efficient coating process refers in particular to improvements in relation to following aspects:

[0053] - Attaining stable operational mode of the arc evaporation source for conducting reproducible coating processes during the complete service life of the arc evaporation source, allowing in this manner deposition of high- quality thick metallic layers in profitable manner (e.g. without incidence of electrical shorts that can lead to coating process breakdowns).

[0054] Figures 1 to 9 are illustrations used to visualize the present invention and are not to be understood as a limitation of the present invention but only as showcases.

[0055] Figure 1 shows an embodiment of an arc evaporation source according to the present invention, in which the ring-shaped confinement element has constant internal diameter 51 and constant external diameter 52, and in which the pole north of the coil 100a and the pole north of the permanent magnet 100b are closer to the target 1 than the pole south, respectively.

[0056] Figure 2 shows a further embodiment of an arc evaporation source according to the present invention, in which the ring-shaped confinement element has variable internal diameter 51 and constant external diameter 52, and in which the pole north of the coil 100a and the pole north of the permanent magnet 100b are closer to the target 1 than the pole south, respectively. Figure 3 shows one more embodiment of an arc evaporation source according to the present invention, in which the ring-shaped confinement element has variable internal diameter 51 and constant external diameter 52, and in which the pole south of the coil 100a and the pole south of the permanent magnet 100b are closer to the target 1 than the pole north, respectively.

[0057] Figure 4 shows one more embodiment of an arc evaporation source according to the present invention, in which the ring-shaped confinement element has variable internal diameter 51 and constant external diameter 52, and in which the pole north of the coil 100a and the pole north of the permanent magnet 100b are closer to the target 1 than the pole south, respectively, and in which the upper surface of the anode 70 is designed to be at a higher distance from the target front surface 10 in comparison to the anode level point 59 in a the ring-shaped confinement element in a direction parallel to the axis A-A that is perpendicular to the target front surface 10.

[0058] Figure 5 shows one more embodiment of an arc evaporation source according to the present invention, in which the ring-shaped confinement element has variable internal diameter 51 and constant external diameter 52, and in which the pole north of the coil 100a and the pole north of the permanent magnet 100b are closer to the target 1 than the pole south, respectively, and in which the upper surface of the anode 70 is designed to be at a higher distance from the target front surface 10 in comparison to the anode level point 59 of the ring-shaped confinement element in a direction parallel to the axis A-A that is perpendicular to the target front surface 10, and the surface of the ring-shaped confinement element that is closest to the target back surface 20 in a direction parallel to the axis A-A that is perpendicular to the target front surface 10, coincides with the target front surface 10 and therefore with the target surface level point 57 of the ring-shaped confinement element .

[0059] Figure 6 shows one more embodiment of an arc evaporation source according to the present invention, in which the ring-shaped confinement element has variable internal diameter 51 and variable external diameter 52, and in which the pole north of the coil 100a and the pole north of the permanent magnet 100b are closer to the target 1 than the pole south, respectively, and in which the upper surface of the anode 70 is designed to be at the same distance from the target front surface 10 in comparison to the anode level point 59 of the ring-shaped confinement element in a direction parallel to the axis A-A that is perpendicular to the target front surface 10, and the surface of the ring-shaped confinement element that is closest to the target back surface 20 in a direction parallel to the axis A-A that is perpendicular to the target front surface 10, does not coincide with the target front surface 10 and therefore does not coincide with the target surface level point 57 of the ring-shaped confinement element but the distance between the surface of the ring-shaped confinement element that is closest to the target back surface 20 in a direction parallel to the axis A-A that is perpendicular to the target front surface 10, is shorter than the distance between the target surface level point 57 of the ring-shaped confinement element and the target back surface 20.

[0060] Figure 7 shows the same embodiment of an arc evaporation source according to the present invention as shown in Figure 6. Furthermore, in Figure 7 are shown 3 sparks placed on the target front surface 10, which are actually in motion above the target front surface 10, wherein each spark has the same current density.

[0061] Figure 8 shows the magnetic field lines generated in an arc evaporation source according to the present invention and in this Figure 8 it is also shown how one of the sparks placed at the target front surface border line is going outside the target front surface 10 in this manner “falling dawn” guided by the magnetic field lines and subsequently extinguishing (image shown how the spark extinguishes is not shown).

[0062] Figure 9 shows also how one of the sparks placed at the target front surface border line is going outside the target front surface 10 in this manner “falling dawn” and subsequently extinguishing (image shown how the spark extinguishes is not shown).

[0063] The inventors observed how after the spark goes beyond the border line of the target front surface 10 and “falls down” and extinguishes, one of the sparks remaining at the target front surface 10 receive an increment of the current intensity equivalent to the current intensity that was present in the spark recently extinguished and immediately afterwards the spark having the increment in the current density divides itself in two sparks each one with the half of the previously attained increased current density. In this manner the sparks remain moving along the complete target front surface 10 in such a manner that a homogeneous removal of the target surface material being evaporated is obtained and the process works stable and the layer deposition rates are higher that with known arc evaporation sources.

[0064] Thus, due to the homogenous removal of the target surface during arc evaporation process, the deposition rate is increased.

[0065] Furthermore, the design of the inventive arc evaporation source allows operation of the target 1 as cathode during the complete life of the target 1 (it means as long target material is available to be evaporated). In this manner, thick layers, in particular thick metallic layers can be deposited in an efficient and reliable manner without requiring stops of the coating processes during layer deposition.

[0066] One of the huge advantages of the setup as described above is that target thicknesses of at least up to 20 mm can be efficiently used to coat thick coating layers. While with earlier setups only target thicknesses of up to 10 mm where economically feasible, due to the outstanding homogeneity of the target material removement by using the arc evaporation source of the present invention, the target 1 can be chosen to be considerably thicker than 10 mm. In case thick coating layers need to be coated the limit of 10 mm meant that before reaching the actual desired coating thickness was reached, the coating process had to be stopped and the target had to be replaced.

[0067] With the new arc-evaporation source according to the present invention in most cases it is no more necessary to stop and exchange the coating process in order to finalize the coating thickness to be realized.

[0068] The main example in order to explain the invention, relates to the ability of producing coatings of thick metallic layers. However, since the described coating processes may be performed for example in a reactive manner the aspects according to the invention are not limited to a coating of metallic layers, but are also transferable to coatings which comprise at least partially oxides, carbides and other reactive materials.

[0069] All aspects described in the application may be realized alone or in combination with other aspects.

Claims

Claims1. An arc evaporation source, comprising:- a target (1 ) to be operated as cathode comprising material to be evaporated, the target (1 ) exhibiting a target front surface (10), a target back surface (20) and a target lateral surface (30), where the target lateral surface (30) extends from the border of the target front surface (10) to the border of the target back surface (20) and the distance between the target front surface (10) and the target back surface (20) along a respective perpendicular axis (A-A) corresponds to the target thickness,- an electrode as anode (70) having an inner surface for acting as electron receiving surface,- a magnetic guidance system comprising means (100) for creating magnetic fields comprising magnetic field lines located in front of the target front surface (10), and- confinement means (50) placed at least partially surrounding the target lateral surface (30). characterized in that the confinement means (50) being designed as one or more ring-shaped confinement elements, wherein at least the part of the target lateral surface (30) adjacent to the target front surface (10) is surrounded by the at least one ring- shaped confinement element and the at least one ring-shaped confinement element has an internal diameter with an internal surface (51 ) and an external diameter with an external surface (52), wherein the internal diameter is smaller than the external diameter and wherein at least at a position in which the at least one ring-shaped confinement element is placed surrounding the target lateral surface (30), the internal diameter is variable in a direction that is parallel to the perpendicular axis (A-A).

2. The arc evaporation source according to claim 1 , characterized in that at least the target front surface (10) is made of material to be evaporated.

3. The arc evaporation source according to claim 1 or 2, characterized in that the confinement means (50) with a confinement height (55) are arranged in the arc evaporation source in a way that a lateral gap is formed between the target (1 ) and the confinement means (50), wherein preferably the lateral gap has a variable diameter.

4. The arc evaporation source according to one of the preceding claims, characterized in that the internal diameter of the confinement means (50) changes constantly, preferably constantly along its entire confinement height (55).

5. The arc evaporation source according to one of the preceding claims, characterized in that the inner diameter of the confinement means (50) is largest in the area surrounding the target lateral surface (30).

6. The arc evaporation source according to one of the preceding claims, characterized in that the confinement means (50) is located between the target (1 ) and the anode (70), preferably completely between the target (1 ) and the anode (70).

7. The arc evaporation source according to one of the preceding claims, characterized in that the external diameter is constant or variable in a direction that is parallel to the perpendicular axis (A-A).

8. The arc evaporation source according to one of the preceding claims, characterized in that there is a gap (80) between a point of the internal surface (51 ) of the at least one ring-shaped confinement element that is closest to the target lateral surface (30) and the lateral surface (30), wherein preferably the gap (80) corresponds to a distance in a direction that is perpendicular to the perpendicular axis (A-A), which is in particular in a range between 0.5 mm and 5 mm.

9. The arc evaporation source according to one of the preceding claims, characterized in that the at least one ring-shaped confinement element exhibiting a confinement height (55) extending from a target surface level point (57) that is placed at the same level of the target front surface (10) up to an anode level point (59) that is placed at the topmost surface of the at least one ring-shaped confinement element, wherein preferably the confinement height (55) is the distance between the target surface level point (57) and the anode level point (59) in a direction parallel to the perpendicular axis (A-A), wherein in particular the confinement height (55) can be kept constant during the coating process even while the thickness of the target (1 ) is decreasing.

10. The arc evaporation source according to one of the preceding claims, characterized in that said means (100) being designed and adjusted for producing a magnetic field region comprising field lines that are substantially perpendicular to the target front surface (10), i.e. substantially parallel to the perpendicular axis (A-A).

11. The arc evaporation source according to one of the preceding claims, characterized in that said confinement height (55) and confinement means (50) are selected and adjusted in such a manner that sparks are allowed to move at the border line of the target front surface (10), and if a spark is moving at the border line of the target front surface (10) the spark cannot follow the magnetic field lines to attain the electron receiving surface of the anode (70) but is guided by the magnetic field lines to go outside of the target border line in direction to the means (100), in order to produce an extinction of the spark and subsequently an increment of a current density in one of the sparks remaining on the target front surface (10), in order to result in turn in a separation of the spark receiving an increment of current density in two sparks.

12. The arc evaporation source according to one of the preceding claims, characterized in that said confinement height (55) and confinement means (50) are selected and adjusted in such a manner that a homogeneous motion of the sparks along the complete target front surface (10) is feasible, resulting in a homogeneous remove of target surface material by evaporation.

13. The arc evaporation source according to one of the preceding claims, characterized in that the target (1 ) has a starting thickness of more than 10 mm, preferably a starting thickness between 15 mm and 40 mm, in particular a starting thickness of 20 mm.

14. The arc evaporation source according to one of the preceding claims, characterized in that the target, the magnetic guidance system and the confinement means (50) are designed be operated with at least two arc-spots and preferably to allow an arc-spot randomly to move outside the target area and to extinguish.

15. The arc evaporation source according to one of the preceding claims, characterized in that gap (80) corresponds to a distance in a range from 1 mm up to 3 mm.

16. The arc evaporation source according to one of the preceding claims, characterized in that gap (80) corresponds to a distance in a range from 1 mm up to 2.5 mm.

17. The arc evaporation source according to one of the preceding claims, characterized in that the confinement height (55) is in a range from 2 mm up to 100 mm.

18. The arc evaporation source according to one of the preceding claims, characterized in that the means (100) comprises an electromagnetic coil (100a) and a permanent magnet (100b), wherein preferably both having identically directed north and south poles, and both placed in relation to the target (1 ) in such a manner that the target back surface (20) is in each case closer to the polarity north than to the polarity south of each one of the electromagnetic coil (100a) and the permanent magnet (100b) or the target back surface (20) is in each case closer to the polarity south than to the polarity north of each one of the electromagnetic coil (100a) and the permanent magnet (100b).

19. A coating device comprising a vacuum coating chamber comprising at least one chamber interior wall, characterized in that an arc evaporation source according to one of the preceding claims is fixed at a surface of the chamber interior wall by using fixing means (60a, 60b), wherein preferably the fixing means (60a, 60b) comprises at least a back plate.

20. The coating device according to claim 19, characterized in that the fixing means (60a, 60b) comprises a lateral fixture system.21 . An arc evaporation coating method, preferably carried out by using an arc evaporation source according to one of the preceding claims, the method comprising the steps of: a) invoking at least a first arc-spot and a second arc-spot at least for a certain time interval running separately both on the front surface of a target, b) provoking the first arc-spot to divide into two separated arc-spots, thereby forming a third arc-spot and a fourth arc-spot, characterized in that the division of the first arc-spot into two separated arc-spots is provoked by letting extinguish the second arc-spot.

22. An arc-coating method according to claim 21 , characterized in that the extinguishing of the second arc-spot is reached by allowing the second arc-spot to move beyond the border of the target into an area with a surface which does not allow it to extract electrons from the surface any more.

23. An arc-coating method according to one of claims 21 to 22, characterized in that the material of the target is a MCrAlY material.

24. An arc-coating method according to one of claims 21 to 23, characterized in that the method is performed within a vacuum chamber of a coating device after establishing a vacuum within the vacuum coating chamber.

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