Cathodic arc source

Abstract

The invention relates to a cathodic arc evaporation device, which comprises: - a target (3) having a target surface (3') including an active surface (3''), from which material can be evaporated in a cathodic arc method; - a limiting part (4) surrounding the outer boundary of the target surface (3'); - an anode (2) having an electron-accepting surface (2', 2'', 2'''), the anode (2) including at least one of the target (3) and the limiting part (4) in at least one of the target plane and the axial distance in front of the active surface; - a magnetic guiding system adapted to provide a magnetic field substantially parallel to at least the outer region of the target surface at the target surface, such that the magnetic field lines are parallel to the target surface or inclined at an acute angle α to the target surface, where the active surface (3'') is defined in the region of the surface (3'), and where the magnetic field lines enter the target surface at an acute angle α ≤ 45°; - a central axis Z or a central plane Z'; wherein both the limiting part (4) and the anode (2) are made in a closed geometric shape and are electrically insulated from each other and from the target, where the minimum distance of the electron-accepting surface (2', 2'', 2''') from the active surface (3'') is defined by the radial distance Δr from the outer boundary of the target surface (3') to the inner boundary of the electron-accepting surface 14 At least one of them is defined, whereby the outer boundary of the target surface (3') has a radial distance r1 from the middle of the target, and the inner boundary of the electron-accepting surface has a radial distance r4 from the middle of the target, and an axial distance h1 from the target surface (3') to the upper boundary of the limiting part or an axial distance h2 from the target surface (3') to the lower boundary of the electron-accepting surface (2', 2'', 2''').

Description

[0001] The present invention relates to a cathodic arc evaporation device, a method for depositing a hard coating on a substrate, and a method for producing a coated substrate. Background Art

[0002] Cathodic arc evaporation devices (also referred to herein as arc sources or arc evaporation sources) are well known as main devices in the field of physical vapor deposition (PVD) for a large variety of surface treatment and coating deposition methods, especially in the field of tool coating, and to some extent also in the field of component coating. However, despite the wide range of applications, the sources in the prior art still have some inherent drawbacks, namely the high heat load transferred from the surface of the arc source to the substrate, and the high-density "particles" commonly referred to as "droplets" or "large particles", which may occur when the arc gets stuck (in other words, when the arc spot remains on a point of the target surface to be evaporated for such a long time that the target material from the target surface melts without the possibility of proper evaporation and subsequent ionization), which usually (especially on metal surfaces) results in a melting pool, which evaporates in an explosive manner, forming so-called droplets with sizes up to several micrometers, which can be found on the substrate surface and in the coating.

[0003] So far, only filtered arc sources can solve these two problems. However, such arc sources are very expensive due to their complex magnetic structure, and have lost the high productivity of conventional arc sources in terms of coating rate and the benefits of being robust and easy to handle and process.

[0004] For another type of source, namely the so-called manipulated arc source, there have been some promising developments, in which the arc is confined to the surface by a static or dynamic magnetic field and moves in a specific path at a greater speed than a random arc.

[0005] Krassnitzer et al. proposed in WO 2011 / 160766 A1 an arc source as shown in Figure 5 for being able to produce a layer with a low surface roughness at a constant high evaporation rate, the arc source comprising a cathode (target), an anode, and a magnetic device, the magnetic device enabling magnetic field lines to lead from the target surface to the anode in a short-circuit connection manner. In this way, the behavior of the potential in front of the substrate is no longer distorted, because the electron temperature of such a plasma is only about 0.3 eV to 1 eV.

[0006] However, there is still a need for improvement, especially regarding obtaining a higher reduction in droplet formation in coatings produced by reactive cathodic arc evaporation methods, where it is necessary to evaporate a target made of a material composed of a large proportion of chemical elements with a low melting point (such as aluminum) or containing a large proportion of chemical elements with a low melting point (such as aluminum).

[0007] Object of the Invention

[0008] One of the objectives of the present invention is to provide a new arc source, which constitutes a solution for overcoming the above problems of the arc source according to the prior art. In particular, the present invention should provide a new arc source that can coat a substrate by using reactive cathode arc deposition technology in such a way that the heat load (and thus the substrate temperature) on the surface of the substrate to be coated can be kept as low as possible, but at the same time, a further reduction in the size and density of droplets in the coating can be achieved. Detailed Description

[0009] The objective of the present invention is achieved by providing the arc source of the present invention as described below.

[0010] The arc source (cathodic arc evaporation device) according to the present invention comprises:

[0011] - A target as the cathode, which has

[0012] ○ A front target surface of the material to be evaporated (hereinafter also simply referred to as the target surface) (in the specification of the present invention, the target surface to be evaporated is also called the active target surface, and the active target surface is the target surface from which the material evaporates during the cathodic arc evaporation method),

[0013] ○ A back target surface, which is parallel to the front target surface but faces a target back plate placed on the opposite side with respect to the front target surface, and

[0014] ○ A side target surface (hereinafter also called the boundary or the boundary of the target), which connects the front target surface and the back target surface,

[0015] - An electrically floating limiting member (hereinafter also called the limiting member or simply the limiting part or the electrically floating arc spot limiting part), preferably annular. However, other structures can also be considered. For example, the limiting member can be square or rectangular in shape, where the limiting member is located adjacent to, preferably around, or at least partially around (but not in direct contact with) the side target surface. In particular, the limiting part is placed around the outer boundary of the target surface (this particularly means that the limiting part is located on the surface around the boundary of the target, and this surface is adjacent to the front target surface). The electrically floating limiting member comprises an inner surface and an outer surface, and the side target surface is closer to the inner surface of the limiting member than to the outer surface of the limiting member.

[0016] - An electrode as the anode, which has an inner surface serving as an electron acceptance surface,

[0017] - A magnetic field generating device (hereinafter also simply referred to as the magnetic guiding system or simply the magnetic device), which is adapted to provide a magnetic field comprising magnetic field lines located in front of the front target surface,

[0018] Wherein:

[0019] - The inner surface of the restricting member is placed at:

[0020] · If considering the distance in a vertical plane relative to the front target surface, between the front target surface and the electron acceptance surface of the anode, and / or

[0021] · If considering the distance in a plane parallel to the front target surface, between the side target surface and the electron acceptance surface of the anode, and

[0022] - The magnetic field generating device is designed and adjusted to produce at least the following two magnetic field regions:

[0023] ○ A first region that contains magnetic field lines in front of the front target surface, the magnetic field lines leaving the front target surface and terminating at the inner surface of the restricting member, and

[0024] ○ A second region that contains magnetic field lines in front of the front target surface, the magnetic field lines leaving the front target surface and terminating at the electron acceptance surface of the anode,

[0025] So that when the arc source is operated in a vacuum chamber, three plasma regions or plasma zones can be produced, where:

[0026] - A first plasma region (plasma A region or bright plasma A region or high electron temperature plasma A region) contains electrons, and due to the magnetic field lines leaving the front target surface and terminating at the inner surface of the restricting member, the electrons cannot approach the anode through the magnetic field,

[0027] - A second plasma region (plasma B region or dark plasma B region or low electron temperature plasma B region), where electrons drift to the anode through the magnetic field lines leaving the front target surface and terminating at the electron acceptance surface of the anode, thereby closing the primary circuit, and

[0028] - A third plasma region (plasma C region or dark plasma C region or low electron temperature plasma C region), where there are no magnetic field lines that neither leave the front target surface and terminate at the inner surface of the restricting member nor leave the front target surface and terminate at the electron acceptance surface.

[0029] In this way, by using the arc source of the present invention, surprisingly large improvements are obtained, which simultaneously involve the following three advantages:

[0030] - Reduced electron temperature in plasma regions B and C, and thus reduced electron temperature of the plasma (usually plasma region C) surrounding the substrate to be plasma-treated or coated, which results in a reduced heat load on the substrate, which is advantageous for: ○ Coating or plasma-treating substrates made of or containing temperature-sensitive materials,

[0031] ○ Forming coating materials that require low temperatures for the corresponding synthesis,

[0032] - Reduced ionization of the reactive gas in regions B and C, and thus reduced amount of reactive gas ions (e.g., if nitrogen is used as the reactive gas, the amount of gas ions N + and N 2+ is reduced), which results in the possibility of synthesizing coating materials, promoting their synthesis by reducing or eliminating reactive gas ions.

[0033] - The size and amount of droplets in the coating are significantly reduced, which is due to the increased plasma density of reactive gas ions in plasma region A, because the reactive gas ions react with the material of the front target surface, causing a change in the state of the front target surface material (e.g., if the material of the front target surface is a metal or semi-metal and nitrogen is used as the reactive gas, the gas ions N + and N 2+ react with the metal or semi-metal of the front target surface, causing nitration of the front target surface material, in such a way that smaller and / or fewer droplets are produced (e.g., if the target material is Ti or Al or AlTi and nitrogen is the reactive gas, during nitridation of the front target surface, a nitride layer of TiN or AlN or AlTiN is formed, resulting in an increased manipulation speed of the arc spot traveling on the nitride layer, reducing the evaporation rate of the front target surface material and emitting fewer droplets, thereby depositing a coating on the substrate placed in region C, which exhibits lower roughness (i.e., has a smoother surface).

[0034] Definition:

[0035] The term cathode arc evaporation device is used synonymously with the term arc source and is also used synonymously with the term arc evaporation source in this application.

[0036] Unless otherwise specified, the radial (r1,... rn) and axial (h1,... hn) distances and the terms higher and lower and their corresponding equivalents are used with reference to the configuration of the arc source as shown in the figures. Unless otherwise specified, the terms inner and outer are used with reference to the axis or centerline Z of the arc source, where Z defines the innermost position. However, those skilled in the art know that the arc source can be arranged at any position in the vacuum chamber, which means at the bottom, side, or top (not shown) of the vacuum chamber, and thus the terms are to be interpreted respectively as shown in the figures for the arc source.

[0037] Surprisingly, it can be shown that the arc source of the present invention can also be used for depositing a compound composition that is further away from the thermodynamic equilibrium state than the compound compositions that can be provided by sources known in the prior art. This is thus a further subject of the present invention.

[0038] More details and preferred embodiments of the cathodic arc evaporation device according to the present invention and of the method using at least one cathodic arc evaporation device according to the present invention will be explained in more detail below.

[0039] In a preferred embodiment of the cathodic arc evaporation device according to the present invention, the device comprises - a target having a target surface (referred to above as the front target surface), which comprises an active target surface (referred to above as the surface to be evaporated), from which material can evaporate in the cathodic arc method;

[0040] - a confinement that surrounds the outer boundary of the target surface, where the confinement can be a one-piece body or a confinement body consisting of several confinement elements;

[0041] - an anode having an electron-accepting surface, the anode comprising at least one of the target and the confinement in at least one of the target plane and the axial distance in front of the active target surface;

[0042] - a magnetic guiding system adapted to provide a magnetic field that is substantially parallel to at least an outer region of the target surface at the target surface, where the outer region can comprise at least 50%, or 70%, or even 90% and more of the target surface. In this context, substantially parallel means that the magnetic field lines are parallel to the target surface or are inclined at an acute angle α ≤ 45°, or α ≤ 30°, or even α ≤ 25° to the target surface, thereby defining the active surface area. It should be mentioned that the effects such as electron capture, as described in detail below, will increase with a higher degree of magnetic field parallelism at and near the target surface (e.g., in zone A), also see below; - the central axis Z for a circular arc source or the central plane Z' for a polygon (e.g., a rectangular arc source);

[0043] Both the confinement and the anode are preferably made in a closed geometric shape, for example, as a ring or a polygon (such as a rectangle, etc.), and both are electrically insulated from each other and from the target. There, the minimum distance between the electron-accepting surface and the active target surface is defined by at least one of the following geometric parameters: the radial distance Δr from the outer boundary of the target surface to the inner boundary of the electron-accepting surface 14 whereby the outer boundary of the target surface has a radial distance r1 from the middle of the target, and the inner boundary of the electron-accepting surface has a radial distance r4 from the middle of the target, and the axial distance h1 or h2 from the target surface to the upper boundary of the confinement or the lower boundary of the electron-accepting surface. This distance can be regarded as an axially effective distance for an increase in the discharge voltage of the reference arc source.

[0044] Thus, during the cathodic arc process, a high plasma density can be achieved in front of the outer region of the target. Due to the substantially surface-parallel magnetic field and the floating potential formed at the isolated constriction, most of the impinging electrons bounce back into the high-density plasma, where they are trapped and forced to perform circular motions similar to the particle orbits of the sputtering target. Only when the electrons escape the outermost magnetic field lines (which still enter the constriction at an axial distance h1 and a radial distance r4), will the electrons be driven towards the anode, which is usually at ground potential and be neutralized at the anode, since there is still a significant magnetic field in the region between the electron receiving surface and the target surface.

[0045] Thus, the substantially parallel magnetic field can extend from the active target surface to at least the axial distance (h1 or h2) of the constriction or the electron receiving surface, or can extend to a height of at least 5 - 20 mm above the target surface.

[0046] In any embodiment of the present invention, a region A above the active region including the substantially parallel magnetic field is provided, where the magnetic flux density B A can be set to 20 - 500 gauss or even higher. For example, it is about 40 - 60 gauss at the middle diameter of the target surface, and when using a ferromagnetic center limiter, it is about 500 gauss or even higher at a few millimeters very close to the ferromagnetic center limiter. Region A is laterally limited by the constriction, which also limits the outer boundary or diameter of the active target surface. Towards the center of the target, region A is bounded by the non-active surface region of the target or the center limiter, in the non-active surface region, the magnetic field lines enter the target surface at an angle > 45°, and the center limiter can have the nature of a magnetic center yoke, as described below. In the axial direction from the target, region A is bounded by the last magnetic field lines that still enter the constriction, which are immediately before the next magnetic field lines entering the electron receiving surface, for example, at its lowest boundary or its innermost boundary.

[0047] The constriction can be made of magnetic or non-magnetic materials, for example, magnetic steel for the center limiter, see below, or made of non-magnetic steel, ceramics, or other materials that can withstand high heat loads near the active target surface.

[0048] The radial distance Δr between the outer diameter of the active target surface and the inner diameter of the electron receiving surface 14 is 5 - 30 mm, for example, 20 ± 5 mm. This distance can be regarded as the radial effective distance for the increase of the discharge voltage of the reference arc source.

[0049] The radial distance r1 of the outer boundary of the target surface from the center of the device is 80 - 220 mm, for example, 15 ± 5 mm.

[0050] The axial distance (h1 or h2) is 0 - 20 mm, for example, 15 ± 5 mm.

[0051] The maximum axial distance h3 of the electron - accepting surface from the target surface can be: 10 ≤ h3 ≤ 50.

[0052] The magnetic guiding system can comprise at least a central magnet and a peripheral annular magnet. The central magnet has magnetic poles placed in front of the center of the back surface of the target and axially aligned therewith. The peripheral annular magnet has opposite magnetic poles in or below the target plane. The annular magnet is expected to enclose at least a part of the central magnet and the target. When they overlap, for example, when the inner diameter of the annular magnet is smaller than the outer diameter of the target, otherwise preferably the annular magnet will enclose the whole target.

[0053] At least one of the central magnet and the annular magnet can be an electromagnet or a permanent magnet. When using a permanent magnet, the corresponding magnet can be made of a single piece or by an arrangement of permanent magnets, for example, arranged in a circular arrangement with the same polarity as the annular magnet.

[0054] The magnetic axis of the annular magnet can be inclined away from the central axis Z or the plane Z’ in an upward direction. While the axis of the central magnet is typically centered and parallel to the axis Z.

[0055] In a further embodiment of the present invention, the annular magnet can comprise two electromagnetic coils C2 and C3, whereby the diameter of C3 is greater than the diameter of C2. Such coils can have separate coil yokes or a common coil yoke and can be mechanically or only magnetically connected to the peripheral yoke, see below.

[0056] The magnetic guiding system of any embodiment can further comprise a peripheral yoke including the annular magnet, the target, and the anode. The peripheral yoke is made of a magnetizable material, for example, iron, martensitic steel, or the like.

[0057] In a further embodiment, the magnetic guiding system can further comprise a central limiter arranged in or around the center of the target surface. The central limiter is electrically insulated from the target and is made of a magnetic material with a Curie temperature T C > 500 °C, T C > 600 °C, or even T C > 650 °C. The corresponding material can be, for example, pure iron, structural steel with a low carbon content, or ferritic corrosion - resistant steel with a higher 10.5 mass% Cr content. The width or diameter of such a central limiter can be 20 - 50 mm, for example, 30 - 40 mm, and can be made in a disc - shape or an annular shape for a circular target.

[0058] For example, when at least one of the limiting part and the anode protrudes from the target surface, the central limiter can protrude 0 - 20 mm or 5 - 20 mm above the target surface or even protrude to the axial distances h1 or h2.

[0059] Alternatively, for example, when at least one of the limiting part and the anode protrudes from the target surface, the central limiter can be in the same plane as the target surface. The central limiter can protrude 5 - 20 mm above the target surface or protrude to the axial distances h1 or h2.

[0060] In any embodiment of the present invention, the limiting part can be made of a non-magnetic material.

[0061] In a further preferred embodiment of the present invention, the minimum distance between the electron-accepting surface and the active target surface is defined by the radial distance Δr 14 and the axial distances h1 or h2.

[0062] The present invention also relates to a vacuum chamber comprising the cathode arc evaporation device as described above.

[0063] Furthermore, the present invention also relates to a method of depositing a coating on a substrate in a vacuum chamber by using the cathode arc evaporation device as described above, by using a magnetic guiding system, by applying a substantially parallel magnetic field to at least an outer region of the target surface, wherein the magnetic field lines enter the target surface at an acute angle α ≤ 45°, thereby forming an active target surface, where an electron trap is established at least above the vicinity of the target surface in region A. The method further comprises igniting and maintaining a cathode arc discharge on the active target surface, whereby the arc spot is manipulated by the parallel component of the radial magnetic field, and region A is laterally defined by a limiting part including the floating potential of the target. Region A can be defined to the center of the target by the inactive surface region of the target or by the central limiter. And in the axial direction from the target, region A can be defined by the last magnetic field line 9 that enters the limiting part at its upper boundary.

[0064] The method may further include forming a B region that is formed above the A region up to a distance h3, given by the maximum axial distance of the electron acceptance surface from the target surface. More precisely, in the B region, due to the still existing magnetic field, electrons escaping from the A region can travel in a circular path towards the anode from the B region, starting from the first magnetic field line 8', for example entering the electron acceptance surface at its lowest or innermost boundary, which immediately follows the magnetic field line 9 that constitutes the last magnetic field line, still entering the confinement section at its upper or outermost boundary, and being bounded in the upward direction by the last magnetic field line 8 that enters the electron acceptance surface, for example at its highest or outermost boundary. Both of these magnetic field lines originate from the central magnet or the central limiter. It is evident that the average magnetic field strength in the B region will be lower than the average magnetic field strength in the A region. However, advantageously, the magnetic field strength and magnetic flux in the B region will be substantially higher than zero. For example, a flux of 5 - 20 Gauss can be applied to effectively drive the electrons that can escape the electron trap in the A region towards the anode that laterally bounds the B region. At the anode, the electrons discharge and leave the plasma and thus are no longer available for further ionization or collision processes that would heat the process gas or other parts of the vacuum chamber. Therefore, the heat load at the anode is substantially higher than the heat load of a conventional arc source, which can however be managed by directly or indirectly water-cooling the anode and using a high thermal conductivity anode material such as copper, etc.

[0065] Thus, it is even possible to use an anode of two or more parts, for example an anode having an inner anode ring extension closely fitted to an externally water-cooled anode body, where the inner ring can be easily removed or replaced for repair purposes. At the same time, the heat load on the substrate can be substantially reduced because, on the one hand, the strongly bright luminous arc plasma, in which most of the arriving reactive molecules (such as nitrogen- or oxygen-containing process gases) are immediately ionized, is confined to zone A and does not spread into the vacuum chamber. This bright luminous plasma can have a lateral distribution similar to that known from the so-called tracks of sputtering targets. Thus, if process gases containing nitrogen and oxygen are used simultaneously, the target surface reacts completely, for example nitriding, oxidizing or both, whereby, due to the high melting points of such compounds, the undesired formation of liquid metal pools and their "explosive" evaporation in the arc tracks can be effectively suppressed, which would otherwise lead to high-density interfering droplets on the surface of the coated substrate. On the other hand, the heat of the electrons is effectively absorbed by the water-cooled anode. Tests measuring the temperature difference between the cooling water of the anode and the target show that when the arc evaporation device of the present invention has been used, more than 80%, more than 90% or even 95% of the process energy supplied by the arc source can be discharged through the respective cooling circuits of the target and the anode. However, with a conventional arc source, only 50% to 55% of the heat is discharged through the respective cooling circuit, which means that the heat load on the substrate is reduced by about 90%, and the substrate temperature between 150 °C and 350 °C, especially between 150 °C and 300 °C, can be carried out without the need for separate cooling of the substrate.

[0066] The method can further include a zone C formed above zones A and B, with reference to the deposition process in the vacuum chamber between the arc source and the surface of the substrate to be coated, where the magnetic field is very low or zero, and the atmosphere contains reactive gas molecules and at least one of positively ionized metal ions and positively ionized reactive metal ions. Optionally, the atmosphere can further contain at least one inert gas molecule. With reference to the high ionization in zone A, the rate of ionization of reactive gas molecules in zone C is very low or negligible. Thus, reactive gas molecules and positively ionized metal ions and / or positively ionized reactive metal ions predominate and, as an example, can form at least 80%, for example 95% or even 99% and more, of the reactive atmosphere in which the substrate is immersed.

[0067] By means of a magnetic guiding system and a floating restriction, both of which act like a plasma resistance and can be adjusted by the magnetic field strength and the distances r4, h1 and / or h2, the discharge voltage of the arc source can be increased between 20 V and 50 V, between 25 V and 40 V or between 30 V and 35 V, generating strong ionization of the working gas near the target surface. This is substantially higher than the discharge voltage of known arc sources, which are typically driven by a discharge voltage of up to 10 V to 20 V.

[0068] In summary, by using the arc source of the present invention, the deposition method can be designed to have a high plasma density confined to region A directly above the substrate surface, thereby providing a high reaction between the target surface and the reactive process gas. In region B, electrons can be effectively removed before they can move out into the free space in the vacuum chamber. At the same time, the reactive gas ions from region A can recombine in region B and / or at the anode surface. Thus, region C is substantially free of free electrons, i.e., electrons not bound to molecules or metal ions, and has a low or near-zero reactive gas ion concentration. Referring to the loaded particles, in region C, it can be detected that substantially most are relatively heavy metal ions (Me n+ ) and metal-compound ions (e.g., MeN n+ and / or MeO n+ ), which provide the deposition material and reactive gas molecules in region C, and the reactive gas molecules can react with the incoming metal ions or metal-containing ions on the substrate surface. Other loaded species (such as electrons and nitrogen ions) are mainly confined to regions A and B, which have a high density near the target surface in region A.

[0069] Such plasma modification makes the source very suitable for the low-temperature deposition of hard coatings and the method of depositing compound compositions far from the thermodynamic equilibrium state. As an example, compounds such as AlMeN, AlMeO, or AlMeNO with different stoichiometric compositions can be deposited, where Me represents one or more metals of groups IV, V, or VI of the transition metals (US: groups 4b, 5b, 6b), including Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, and W. As an example of such a coating, the deposition of cubic TiAlN should be mentioned, which can be deposited in its pure cubic phase, even at concentrations of Al up to 70% and 80%. The percentages are given with reference to the metal content of the reference compound (i.e., (Al 0.7 Ti 0.3 )N or (Al 0.8 Ti 0.2 )N). With reference to the metal composition, the reactive elements can be in stoichiometric, sub-stoichiometric, or over-stoichiometric concentrations. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] The present invention will now be further illustrated by means of the drawings. The drawings show:

[0071] Figure 1 : A schematic and simplified first embodiment of the device according to the present invention;

[0072] Figure 2 : A second embodiment of the device according to the present invention;

[0073] Figure 3: The third embodiment of the device according to the present invention;

[0074] Figure 4 : The fourth embodiment of the device according to the present invention;

[0075] Figure 1 Most schematically and simplifiedly shows an embodiment of the arc source I according to the present invention, whereby a planar target 3 with a radial width or diameter of r1 and a corresponding limiting part 4 of the target, and an anode 2 including both the target and the limiting part. The target can be polygonal, for example rectangular, or circular, and thus the center plane or axis of the target is defined by Z. Hereinafter, for the sake of easy understanding, it is called circular, and with reference to Figure 3 and 4 , it is called an annular target. However, such dimensions can be easily converted into other planar targets, that is, targets with a planar surface to be evaporated, which have different shapes, and these shapes are also included in the present invention. Due to Figure 1 the nested structure of the arc source (also refer to Figure 3 and Figure 4 ), the inner diameter r2 of the limiting part will usually be greater than the outer diameter r1 of the target 3, or at least greater than the outer diameter of the active target surface 3”, for example when the limiting part is interpreted as protruding a few millimeters from the target surface (not shown) and forming an arc extinguishing distance in the upward rather than the lateral direction, as shown in the figure. Such a distance (here it is r2 - r1) should be in the range of 1.5 - 3 mm to ensure that the arc extending on the target surface neither spreads into the gap formed between the target and the limiting part nor extends to the limiting part surface. At the same time, the appearance of undesired parasitic plasmas in the gap can be avoided. For the distance r4 - r3 between the outer diameter r3 of the limiting part 4 and the inner diameter r4 of the anode, or for the corresponding axial distance h2 - h1 from the limiting part 4 to the anode 2, a similar distance can be selected, as shown in Figure 2 , or for the anode shape change shown by the dashed line in Figure 1 . Thus, electrical contact between the electrically insulating limiting part and the anode and the formation of undesired plasmas can be effectively avoided.

[0076] In the region where the magnetic field lines enter the target surface at an acute angle α ≤ 45° (the so-called active target surface 3”), an arc can be ignited and manipulated by the radial magnetic field circulation. Thereby, a strongly luminous plasma 10 (also referred to hereinafter as a reactive gas plasma) can be formed, through which reactive gas molecules (such as gases containing nitrogen, oxygen, or carbon) entering this region can be effectively dissociated into their atomic or ionic components and thus assist in the reaction of the metal active target surface or metal ions or clusters leaving the arc running on the surface. Thus, most of the possible reactive plasma processes (such as nitriding, oxidizing, carbonizing, or processes with mixed reactive gases) can occur at or near the target surface in region A, which is in the region between the last magnetic field lines 9 still entering the confinement and the target surface 3’, especially at the outer surface region of the active target surface 3” formed as in the embodiments shown in Figure 1 and Figure 2 Region A can also be regarded as an electron trap because it is expected that electrons are reflected from the confinement wall and plasma escape is only possible when they reach region B between magnetic field lines 9 or 8’ and magnetic field line 8, where magnetic field line 8 enters the electron acceptance surface at its highest or outermost boundary, while magnetic field line 8’ enters the electron acceptance surface at its lowest or innermost boundary, and magnetic field line 8 is adjacent and above magnetic field line 9, also see Figure 2 . In region B, electrons will be neutralized at the anode 2. The electron acceptance surfaces 2’, 2”, 2”’ of the anode 2 can be formed with different geometries, for example, a simple cylindrical shape, and / or with different inclinations relative to axis Z as shown by the dashed line 2” for example, or in a manner protruding over at least a part of the confinement 4 as shown by the dashed line 2”’ in Figure 1 . The anode is further provided with an anode cooling channel 6’, which can be connected to a dedicated or common, for example, water-based cooling pipeline not shown in the figure.

[0077] Similar to the electron acceptance surface defined by the inner surface and / or upper surface of the anode, the inner surface and / or upper surface of the confinement 4 can be formed with different geometries, for example, a simple cylindrical shape, and / or with different inclinations relative to axis Z as shown by the dashed line 4” for example, or protruding over the target surface as shown by the dashed line 4”’ in

[0078] All arc sources of the present invention are further provided with a magnetic guiding system, which is adapted to provide a magnetic field in front of the target surface, the magnetic field being substantially parallel to at least the outer region of the target surface, as in the embodiments shown in Figure 1 and Figure 2 , or even over the entire target surface, as in the embodiments shown in Figure 3 and Figure 4 . Thereby, substantially parallel means that the magnetic field lines enter the active target surface at an acute angle α ≤ 45°, or even more sharply at an acute angle α ≤ 30° or α ≤ 25°, as inFigure 3 Such a magnetic guiding system, shown by way of example in FIGS. 1 and 5, can also be used with any other embodiments, for example, embodiments 1 and 2 of the arc source of the present invention, and will generally include a central magnet 14 and an annular magnet 15, the latter including the central magnet and at least optionally including the target 3. A ferromagnetic outer yoke 17 at ground potential can also assist any embodiment to further form a magnetic field, for example, to limit the extension of magnetic field lines in the radial direction.

[0079] Figure 2 An embodiment of the present invention showing an arc source II having a cylindrical anode 2 disposed on top of a cylindrical confinement, both having the same inner diameter. In this case, essentially only the distance h2 will contribute to the increase in the discharge voltage of the arc source, while in any other embodiment as shown in other figures, the axial distances h1 or h2 and the radial distance r5 - r2 will contribute. The latter distance is Figure 2 almost negligible in

[0080] In another embodiment not shown in the figures, the confinement is formed as a ring including the target at the target surface level, and the anode is formed as a ring including both at the same level. In this case, when disposed at the same level as the target surface 3', when the inner surface 4', 4", 4'" of the confinement and the inner electron acceptance surface are completely replaced by the corresponding upper confinement and anode surfaces, essentially only the radial distance r4 - r1 will contribute to the increase in the discharge voltage of the arc source.

[0081] Figure 3 Showing an Figure 1 arc source III similar to c having a basic magnetic guiding system having its magnetic axis M r in line with the central axis Z of a central permanent magnet 14, while the magnetic axis M of the annular magnet 15 rThe tilt angle relative to the central axis Z can be between 0 - 45°, for example, between 5 - 30°, up to the respective case. Thus, the magnetic interface can also be influenced and tilted accordingly, thereby achieving a flatter or more parallel path of the magnetic field lines above the target surface. In this context, the interface is the plane between the magnetic field lines, which on the one hand extend from one pole (here the south pole of the toroidal magnet) to the opposite pole (here the north pole of the central magnet), and on the other hand from one magnetic pole of the toroidal magnet to the opposite pole of the same toroidal magnet. Those skilled in the art will recognize that the magnetic poles can be exchanged conversely. For example, the ferromagnetic outer yoke 17 at the anode potential, which is usually at ground potential, can also be used to make the magnetic field lines more parallel above the target surface and block the magnetic field in the radial direction outside the outer yoke, and the outer yoke laterally includes the entire arc source. In Figure 3 In it, the central magnet 14 is directly arranged below the target backplate 12, and the target backplate contains target cooling channels, which can be connected to dedicated or common, for example, water-based cooling pipelines not shown in the figure. Alternatively, the central magnet can also be placed within the backplate 12 (e.g., the cooling channel 13).

[0082] In addition, on type III or IV arc sources, see below Figure 4 , there is a ferromagnetic central limiter 16 at the center of the target 3 or at the center of the target 3 at an electrically floating potential. Therefore, the yoke is mounted on an insulator 19 made of an electrically insulating and heat-resistant material such as ceramic, similar to the floating-mounted limiter 4 mounted by means of at least one electrical insulator 20. The gap between the central limiter 16 and the target should have the dimensions of the limiter 4 as described above, that is, in the range of 1.5 - 3 mm.

[0083] With the symbolically shown central limiter 16, the magnetic field lines f m can be formed substantially parallel to the entire target surface 3'. Thus, the active target surface 3'' can also expand over the entire target surface 3', in this case a surface ring. Due to the high heat load in the middle of the target, any central limiter 16 in any embodiment must be made of a magnetic material with a high Curie temperature T C (preferably higher than 600 °C or higher). The magnetic permeability μ of such a material r should be at least higher than 100 or even higher than 500, and the saturation magnetization should be higher than 0.3 Tesla, or even higher than 0.5 Tesla. Such a material should also have a low remanence B r , especially if the magnetic manipulation of the arc should involve a dynamic magnetic field, for example, when the magnetic coil is driven with a variable (e.g., pulsed) current, the corresponding coercive field strength H C should be lower than 200 A / m or even equal to or lower than 50 A / m.

[0084] Examples of such materials are pure iron (such as TC at 766 °C iron), structural steel with a low carbon content (such as T C S235 or S355 steel at about 768 °C), or ferritic corrosion-resistant steel with a chromium content higher than 10.5% (e.g., 17.25 - 18.25, according to ASTM A838 - 02(2007)), T C at 671 °C with a low Si concentration of 0.30 - 0.70 mass%, or T C at 660 °C with a higher Si concentration of 1.00 - 1.50 mass%. The magnetic properties of the outer yoke 17 should be the same. However, since the yoke is far from the hot target surface, austenitic steel with corresponding properties and other cheaper magnetic materials with a much lower Curie temperature can also be used.

[0085] As with Figure 3 in Figure 4 shows an arc source with a ferromagnetic center limiter. This article is in the simplest and schematic vacuum chamber 1 with a substrate 7 mounted above the arc source IV. As opposed to Figure 3 type III arc sources that use permanent magnets in , the magnetic guiding system of type IV arc sources uses electromagnetic coils C1, C2, C3, where the magnet 14 is realized by the electromagnetic coil C1 with a central coil yoke 18, and the toroidal magnet 15 is realized by the electromagnetic coils C2 and C3 and the outer coil yoke 21.

[0086] Figure 4 shows an industrial setup of the implementation of the type IV arc source of the present invention with an electromagnetic guiding system, and the magnetic field lines do refer to the actual magnetic field lines that can be produced using such a system, as the fields H C1 , H C2 and H C3 superimposed. Where the central magnet 14 includes the electromagnetic coil C1 and the central coil yoke 18, and the toroidal magnet 15 includes the electromagnetic coils C2 and C3, and the outer coil yoke 21. To produce such a field magnetic axis Mr, and by applying a higher current to C2 than to C3, the corresponding interface of the toroidal magnet 15 is inclined away from the central axis Z in the upward direction, which means I C2 > I C3 . Alternatively, such an effect can also be produced by supplying the same current to coils of different windings N, e.g., N C2 > N C3。The anode is a two-part anode having an anode body 25 with cooling channels 6 and an inner annular extension 26. The vacuum seal 22 seals the vacuum chamber 1 tightly from ambient air and water from one or more cooling circuits 6, 13. The substrate 7 can be mounted to a substrate support (not shown) in a known (e.g., rotating) manner. Areas A, B, and C are substantially separated from each other by the magnetic field lines 8 and 9 shown. With such a structure, an inclined arc source with an outer diameter of 220 mm can be achieved, where the target diameter is 130 mm and the ferromagnetic center limiter is 36 mm. The total height from the back of the target 3 to the upper boundary of the electron acceptance surface 2 is approximately 53 mm.

[0087] In an industrial environment using an Oerlikon intermittent coating device, with a coating height of 1000 mm, up to 24 type-IV arc sources can be installed in four rows, with 6 arc sources per meter in each row, one arc source above another, whereby hard coatings of the AlMeN and AlMeNO types can be deposited on different substrates at high rates and with high aluminum contents. The aluminum content is 0 - 85%, especially at high aluminum concentrations between 70 - 85%, and for example, in combination with at least one of Ti and Cr, a pure cubic phase compound can be deposited. The chamber of such a device has a diameter of 1000 mm, a turntable with a diameter of 700 mm, and a chamber height of 2000 mm. The substrates are mounted with 1, 2, and 3-fold rotations, and the distance from the nearest substrate to the target is approximately 300 mm. Similar tests were conducted on other industrially available coating systems of the applicant's Innova and Innoventa types. Thus, the industrial applicability can be tested for the following chamber dimensions: chamber diameter 500 - 1200 mm, turntable diameter 300 - 900 mm, chamber height 1000 - 2000 mm, available coating height 500 - 1500 mm.

[0088] The properties and geometric data of certain core components of the arc source of the present invention are listed below:

[0089] · Target: Can be directly cooled according to the corresponding material strength or cooled via a bonded backplate. Both types can be mounted on a water-cooled cathode electrode;

[0090] + Circular diameter D T , 60 mm ≤ D T = 2r1 ≤ 200 mm; 100 mm ≤ D T = 2r1 ≤ 150 mm;

[0091] + Material: Any solid material suitable for arc evaporation.

[0092] · Limiter: Isolatedly mounted between the target and the anode, whereby a potential between the induced cathode target potential and the positive or grounded anode potential is generated during the cathodic arc method.

[0093] + Inner diameter D CI , 95 ≤ D CI = 2 x r2 ≤ 155 mm; for example, 132 mm

[0094] + Thickness t in the radial direction CR (r3 - r2), 10 ≤ t CR ≤ 30 mm; for example, 148 mm; It should be mentioned that the thickness t CR only refers to the surface area of the restriction ring that can be exposed to the arc plasma, and due to the structural characteristics of a specific arc source, the total thickness extension of the restriction ring can be greater, for example, when the anode extension overlaps and thus protects the outside of the restriction ring from interacting with the plasma.

[0095] + Distance h1 from the active target surface to the upper surface or top of the restriction ring, 0 (for planar embodiments) ≤ h1 ≤ 20, for cylindrical and combined embodiments the preferred range, for example, Figures 1-4 , 10 ≤ h1 ≤ 30, for example, 15 ≤ h1 ≤ 25;

[0096] + At least in the area where the restriction ring includes the target in the target plane, the radial distance of the restriction ring is generally defined by the distance d D = r3 - r2 = r4 - r5 = h2 - h1, for which 1.5 mm ≤ d D ≤ 3 mm; thus preventing the arc spot from spreading to the restriction part and parasitic plasma between the components of the source, since this distance conforms to the dark chamber distance with a normal processing pressure;

[0097] + Material: ferromagnetic material, such as iron, carbon steel, etc., but can also be a non-magnetic metal with a high enough melting point to withstand the high heat load of adjacent arc discharges, such as stainless steel.

[0098] · Anode: Set to positive potential or ground potential with internal water cooling;

[0099] + Inner diameter D AI , which also defines the inner diameter of the electrode receiving surface, 80 mm ≤ D AI = 2 x r4 ≤ 220 mm, 120 mm ≤ D AI = 2 x r4 ≤ 170 mm or approximately 150 mm;

[0100] + Thickness t in the radial direction AR , 10 ≤ t AR ≤ 40 mm;

[0101] + The distance h2,0 from the active target surface to the electron-accepting surface or the top of the limiting ring, for example, for a planar embodiment, 0 ≤ h1 ≤ 50, and for cylindrical and combined embodiments, the preferred range is 10 ≤ h1 ≤ 35; when the limiting ring is nested within the anode, for example, according to Figure 1 and 3 , when the anode has electron-accepting surfaces 2’, 2”, h2 can be the same as h1.

[0102] + The material can be copper, carbon steel, or stainless steel.

[0103] · The overall geometry of the cathode assembly

[0104] + The diameter ranges from 150 mm (for example, for cylindrical modification) ≤ Dsource ≤ 290 mm (for example, for planar modification), or 180 mm ≤ Dsource ≤ 260 mm

[0105] · A magnetic guiding system to generate a magnetic field having a high parallel component at least near the outer region of the active target surface. The device containing the guiding system is placed in front of the back surface of the target (for example, on the back plate of the cathode electrode) and is electrically insulated from the electrode. The guiding system can optionally be assisted by a ferromagnetic central limiter electrically insulated (at a floating potential) and mounted at the center of the target surface and / or the peripheral yoke.

[0106] · Ferromagnetic central limiter:

[0107] + Circular diameter D Y , 15 mm ≤ D Y ≤ 50 mm; for example, 36 mm

[0108] + Material: pure iron, structural steel with low carbon content, ferritic corrosion-resistant steel, details as above

[0109] · The magnetic field that can be set by the source of the present invention:

[0110] + At least for the outer region of the active target surface, at and near the active target surface, it should be substantially parallel;

[0111] + During the cathode arc method, three zones (A, B, C) are formed, possibly having magnetic flux densities B A > B B > B C , details as above;

[0112] · The arc source power supply can be a DC power supply delivering a discharge current (for example, 10 - 200 A, for example, 40 - 120 A for each source). Alternatively, a pulsed arc power supply or a DC power supply with a superimposed pulsed power supply can be used.

[0113] · Contrary to the prior art sources driven by a discharge voltage between 12 - 20 V, due to the geometry, materials, and magnetic means of this arc source, with the higher resistance of the electron traps that can be formed in region A, this source can be driven with a discharge voltage between 20 - 50 V (e.g., 25 - 40 V or 30 - 35 V).

[0114] Finally, it should be mentioned that, unless contradictory, combinations of features mentioned in one embodiment, example, or type of the present invention can be combined with any other embodiment, example, or type of the present invention.

[0115] Reference numerals

[0116] 1 Vacuum chamber

[0117] 2 Anode

[0118] 2', 2", 2""" Electron acceptance surface of the anode

[0119] 3 Target

[0120] 3’ Target surface

[0121] 3” Active target surface

[0122] 4 Limiting part at an electrically floating potential

[0123] 4', 4", 4''' Inner surface of the limiting part

[0124] 5 Arc discharge power supply

[0125] 6 Cooling channel anode

[0126] 7 Substrate (biased / non - biased)

[0127] 8, 8’ Magnetic field lines to the anode

[0128] 9 Magnetic field lines to the limiting part

[0129] 10 Gas plasma

[0130] 11 Gas inlet (N2, O2, CH4, C2H2, Ar)

[0131] 12 Target backplate

[0132] 13 Cooling channel backplate

[0133] 14 Central magnet

[0134] 15 Ring magnet

[0135] 16 Electrically floating ferromagnetic central limiter

[0136] 17 Ferromagnetic outer yoke at ground potential

[0137] 18 Central coil yoke

[0138] 19 Insulator for central limiter

[0139] 20 Insulator for limiting part

[0140] 21 Outer coil yoke

[0141] 22 Seal

[0142] 23 Electrical insulator for target

[0143] 24 Anode base

[0144] 25 Anode extension

[0145] 26 Part of the chamber or component of the chamber or within the chamber, e.g., preferably a flange or part of a flange electrically connected to the anode such that they are at the same potential

[0146] C1, C2, C3 Electromagnetic coils 1, 2, 3

[0147] h1 Axial distance from the active target surface 3” to the upper boundary 4 of the limiting part:

[0148] h2 Axial distance from the active target surface 3” to the lower boundary of the electron acceptance surfaces 2’, 2”, 2”’, which may be the same as h1, e.g., see Figure 2 Left - hand electron acceptance surfaces 2', 2”

[0149] h3 Axial distance from the active target surface 3” to the upper boundary of the electron acceptance surfaces 2’, 2”, 2”’

[0150] M Magnetic axis

[0151] r1 Radial distance from the center axis for a circular target 3 or for a polygon (e.g., rectangular target 3) radial distance from the center plane

[0152] r2 Radial distance from the center axis / plane to the inner diameter / boundary of the limiting part 4

[0153] r3 Radial distance from the center axis / plane to the outer diameter / boundary of the limiting part 4

[0154] r4 Radial distance from the center axis / plane to the inner diameter / boundary of the electron acceptance surfaces 2’, 2”, 2”’

[0155] r5 Radial distance from the center axis / plane to the outer diameter / boundary of the electron acceptance surfaces 2', 2”, 2”’

[0156] r6 Radial distance from the center axis / plane to the outer boundary of the arc source

[0157] Z for the central plane or axis of a polygonal or circular target

[0158] Specifically, the present application relates to a cathodic arc evaporation device, which comprises:

[0159] - a target as a cathode, which has

[0160] ○ a front target surface of the material to be evaporated, i.e., the active target surface,

[0161] ○ a back target surface, which is parallel to the front target surface but faces a target back plate placed on the opposite side with respect to the front target surface, and

[0162] ○ a side target surface, which connects the front target surface and the back target surface,

[0163] - an electrically floating limiting part, which is located adjacent to, preferably surrounding or at least partially surrounding the side target surface, the limiting part comprising an inner surface and an outer surface, wherein the side target surface is closer to the inner surface of the limiting part than to the outer surface of the limiting part.

[0164] - an electrode as an anode, which has an inner surface serving as an electron acceptance surface,

[0165] - a magnetic guiding system, which is adapted to provide a magnetic field comprising magnetic field lines located in front of the front target surface,

[0166] Wherein:

[0167] - the inner surface of the limiting part is placed at:

[0168] · If considering the distance in a vertical plane with respect to the front target surface, between the front target surface and the electron acceptance surface of the anode, and / or

[0169] · If considering the distance in a plane parallel to the front target surface, between the side target surface and the electron acceptance surface of the anode, and

[0170] - the magnetic guiding system is designed and adjusted to produce at least the following two magnetic field regions:

[0171] ○ a first region, which comprises magnetic field lines located in front of the front target surface, the magnetic field lines leaving the front target surface and terminating at the inner surface of the limiting part member, and

[0172] ○ a second region, which comprises magnetic field lines located in front of the front target surface, the magnetic field lines leaving the front target surface and terminating at the electron acceptance surface of the anode.

[0173] The device preferably includes an electrically floating ferromagnetic center limiter (16) for modifying the trajectory of the magnetic field lines leaving the front target surface such that the magnetic field lines are substantially parallel to the plane of the front target surface.

[0174] The invention also relates to a method for operating the device of the invention, wherein during the operation of the device in a vacuum chamber, three plasma regions or zones are produced, wherein:

[0175] - The first plasma region contains electrons which, due to the magnetic field lines leaving the front target surface and terminating at the inner surface of the limiting member, cross the magnetic field and cannot approach the anode.

[0176] - A second plasma region, wherein electrons drift to the anode through the magnetic field lines leaving the front target surface and terminating at the electron receiving surface of the anode, and

[0177] - A third plasma region, wherein there are no magnetic field lines that neither leave the front target surface and terminate at the inner surface of the limiting member nor leave the front target surface and terminate at the electron receiving surface.

[0178] The electron temperature by applying the above method is preferably:

[0179] - Between 1 eV and 5 eV in the first plasma region, and

[0180] - Between 0.3 eV and 1 eV in the second and third plasma regions.

[0181] Preferably, the method of the invention includes at least one step wherein a reactive gas is introduced into the vacuum chamber and the device is operated while introducing the reactive gas, wherein the first plasma region contains more reactive gas ions than the second and third plasma regions, and thus the reactive gas ion density in the first plasma region is higher than the reactive gas ion density in the second and third plasma regions.

[0182] In a preferred embodiment of the method, the target or at least the front target surface is made of a metallic material and the reactive gas reacts with the metallic material from the target to produce a layer containing elements from the reactive gas as well as elements from the metallic material.

[0183] According to a further preferred embodiment, the target consists of or contains Ti or Al or Al and Ti, and the reactive gas is nitrogen or contains nitrogen, such that the layer produced by the reaction of the reactive gas with the metallic material from the target is a nitride layer consisting of or containing TiN or AlN or AlTiN, respectively.

[0184] According to an even more preferred embodiment, the target material is selected from Al and Ti or contains Al and Ti, in a concentration allowing the synthesis of a coating on a substrate placed in the third plasma region, the coating consisting of or containing cubic aluminum nitride having an elemental composition Al x Ti 1-x N, where x is the atomic concentration fraction of Al, where X is 0.8.

[0185] In a more detailed embodiment of the cathodic arc evaporation device of the present invention, it comprises

[0186] - a target (3) having a target surface (3') including an active target surface (3''), from which material can evaporate in the cathodic arc method;

[0187] - a restricting portion (4) surrounding the outer boundary of the target surface (3');

[0188] - an anode (2) having an electron-accepting surface (2', 2'', 2'''), the anode (2) including at least one of the target (3) and the restricting portion (4) in at least one of the axial distances in front of the target plane and the active target surface;

[0189] - a magnetic guiding system adapted to provide a magnetic field substantially parallel to at least an outer region of the target surface at the target surface, such that the magnetic field lines are parallel to the target surface or inclined at an acute angle α to the target surface, where an active target surface (3'') is defined in the region of the target surface (3'), and where the magnetic field lines enter the target surface at an acute angle α ≤ 45°;

[0190] - a central axis Z or a central plane Z';

[0191] where both the restricting portion (4) and the anode (2) are made in a closed geometric shape and are electrically insulated from each other and from the target, where the minimum distance of the electron-accepting surface (2', 2'', 2''') from the active target surface (3'') is given by the radial distance Δr from the outer boundary of the target surface (3') to the inner boundary of the electron-accepting surface 14is defined by at least one of the following, whereby the outer boundary of the target surface (3') has a radial distance r1 from the center of the target, and the inner boundary of the electron acceptance surface has a radial distance r4 from the center of the target, and an axial distance h1 from the target surface (3') to the upper boundary of the restriction or an axial distance h2 from the target surface (3') to the lower boundary of the electron acceptance surface (2', 2", 2''').

[0192] Preferably, the device of the present invention according to any of the above preferred embodiments is adjusted such that a substantially parallel magnetic field extends at least from the active target surface (3'') to the axial distance (h1, h2) of the restriction or the electron acceptance surface, and / or at least to a height of 5 - 20 mm above the target surface.

[0193] In region A above the active target surface, the magnetic flux density B A can be set to an intensity of 20 - 500 gauss or even higher.

[0194] The restriction can be made of magnetic or non - magnetic material.

[0195] Preferably, the radial distance Δr 14 is 5 - 30 mm.

[0196] Preferably, the radial distance r1 of the outer boundary of the target surface from the center of the device is 40 - 110 mm.

[0197] Preferably, the axial distance (h1, h2) is 0 - 20 mm.

[0198] Preferably, the maximum axial distance h3 of the electron acceptance surface is: 10 ≤ h3 ≤ 50.

[0199] Preferably, the magnetic guiding system comprises at least a central magnet and a peripheral annular magnet, the central magnet having a magnetic pole placed in front of the center of the back surface of the target and axially aligned therewith, the peripheral annular magnet having opposite magnetic poles in or below the target plane, and the annular magnet is expected to enclose at least the central magnet and a part of the target.

[0200] Preferably, at least one of the central magnet and the annular magnet is an electromagnet or a permanent magnet.

[0201] Preferably, the magnetic axis of the annular magnet is inclined away from the central axis Z or the plane Z' in an upward direction.

[0202] In a preferred embodiment, the annular magnet comprises two electromagnetic coils C2 and C3, whereby the diameter of C3 is greater than the diameter of C2.

[0203] In a further preferred embodiment, the magnetic guiding system further comprises a peripheral yoke including the annular magnet, the target and the anode, the peripheral yoke being made of a magnetizable material.

[0204] Preferably, the magnetic guiding system further comprises a central limiter disposed in or around the center of the target surface, the central limiter being electrically insulated from the target and made of a magnetic material with a Curie temperature T C > 500 °C.

[0205] In a preferred embodiment, the central limiter protrudes 0 - 20 mm above the target surface, or protrudes to an axial distance h1 or h2.

[0206] In a further preferred embodiment, the central limiter is in a plane with the target surface.

[0207] In a preferred embodiment, the limiting portion is made of a non-magnetic material.

[0208] In a further preferred embodiment, the minimum distance of the electron acceptance surface (2’, 2”, 2”’) from the active target surface (3”) is defined by the radial distance Δr 14 and the axial distance h1 or h2.

[0209] The invention also relates to a vacuum chamber comprising the cathode arc evaporation device of the invention according to any one of the above-described embodiments of the invention.

[0210] The invention also relates to a method of depositing a coating on a substrate in a vacuum chamber by using the cathode arc evaporation device according to the present disclosure, by using a magnetic guiding system, by applying a substantially parallel magnetic field to at least an outer region of the target surface (3’), wherein the magnetic field lines enter the target surface at an acute angle α ≤ 45°, thereby forming an active target surface (3”), and igniting and maintaining a cathode arc discharge on the active target surface, where the A region is laterally bounded by a limiting portion at a floating potential, and where an electron trap is established at least above the vicinity of the target surface within the A region.

[0211] Preferably, a B region is formed above the A region to an axial distance h3, given by the maximum axial distance of the electron acceptance surface from the target surface.

[0212] Preferably, a C region is formed above the A and B regions, where the magnetic field is very low or zero, and the atmosphere contains at least one of reactive gas molecules, positively ionized metal ions, and positively ionized reactive metal ions.

[0213] In a preferred embodiment of the method of the present invention, the cathodic arc discharge is maintained at a discharge voltage between 20V and 50V.

[0214] In a preferred embodiment of the method of the present invention, the coating is an AlMeN, AlMeO or AlMeNO compound, where Me represents one or more metals of groups IV, V or VI of the transition metals.

[0215] The present invention also relates to a method for producing a coated substrate by a deposition method according to any one of the embodiments of the present invention described above.

[0216] In a preferred embodiment, the coated substrate is a tool or a component.

Claims

1. A cathodic arc evaporation apparatus, comprising: i. A target as a cathode, having a front target surface of the material to be evaporated, i.e., an active target surface, a back target surface, which is parallel to the front target surface but faces a target back plate placed on the opposite side with respect to the front target surface, and side target surfaces, which connect the front target surface with the back target surface, ii. An electrically floating restricting portion, which is located adjacent to the side target surfaces, the restricting portion comprising an inner surface and an outer surface, wherein the side target surfaces are closer to the inner surface of the restricting portion than to the outer surface of the restricting portion, iii. An electrode as an anode, having an inner surface serving as an electron acceptance surface, iv. A magnetic guiding system, which is adapted to provide a magnetic field comprising magnetic field lines located in front of the front target surface, characterized in that: If considering the distance in a vertical plane with respect to the front target surface, the inner surface of the restricting portion is placed between the front target surface and the electron acceptance surface of the anode, and / or If considering the distance in a plane parallel to the front target surface, the inner surface of the restricting portion is placed between the side target surfaces and the electron acceptance surface of the anode, and The magnetic guiding system is designed and adjusted to produce at least the following two magnetic field regions: A first region, which comprises magnetic field lines located in front of the front target surface, the magnetic field lines leaving the front target surface and terminating at the inner surface of the restricting portion member, and A second region, which comprises magnetic field lines located in front of the front target surface, the magnetic field lines leaving the front target surface and terminating at the electron acceptance surface of the anode, wherein the magnetic guiding system comprises at least a central magnet and a peripheral annular magnet, the central magnet having magnetic poles placed in front of the center of the back surface of the target and axially aligned therewith, the peripheral annular magnet having reverse magnetic poles in or below the target plane, the annular magnet being expected to include the central magnet and at least a part of the target; and the magnetic guiding system further comprises a peripheral yoke including the annular magnet, the target and the anode, the peripheral yoke being made of a magnetizable material.

2. The device according to claim 1, wherein The electrically floating restricting portion at least partially surrounds the side target surfaces.

3. The device according to claim 1, characterized in that The apparatus comprises an electrically floating ferromagnetic central restrictor (16) for modifying the trajectory of the magnetic field lines leaving the front target surface such that the magnetic field lines are inclined at an acute angle α≤45° with respect to the plane of the front target surface.

4. The cathodic arc evaporation apparatus according to claim 1, comprising a) A target (3), having a target surface (3’), the target surface (3’) comprising an active target surface (3”), from which material can be evaporated in the cathodic arc method; b) A restricting portion (4) surrounding the outer boundary of the target surface (3’); c) An anode (2) having an electron acceptance surface (2’, 2”, 2”’), the anode (2) including at least one of the following: the target (3), and the restricting portion (4), in at least one of the target plane and the axial distance in front of the active target surface; d) A magnetic guiding system adapted to provide a magnetic field substantially parallel to at least an outer region of the target surface at the target surface such that the magnetic field lines are inclined at an acute angle α towards the target surface, wherein, An active target surface (3”) is defined in the region of the target surface (3’), wherein magnetic field lines enter the target surface at an acute angle α≤45°. e) Central axis Z or central plane Z’; Both the confinement part (4) and the anode (2) are made in a closed geometric shape and are electrically isolated from each other and from the target, wherein the minimum distance of the electron acceptance surfaces (2’, 2”, 2”’) from the active target surface (3”) is defined by at least one of the following: the radial distance Δr from the outer boundary of the target surface (3’) to the inner boundary of the electron acceptance surface 14 , whereby the outer boundary of the target surface (3’) has a radial distance r1 from the middle of the target and the inner boundary of the electron acceptance surface has a radial distance r4 from the middle of the target, and the axial distance h1 from the target surface (3’) to the upper boundary of the confinement part or the axial distance h2 from the target surface (3’) to the lower boundary of the electron acceptance surfaces (2’, 2”, 2”’).

5. A cathodic arc evaporation device, comprising I. A target (3) having a target surface (3’), said target surface (3’) comprising an active target surface (3”), from which material can be evaporated in a cathodic arc process; II. A limiting part (4) surrounding the outer boundary of said target surface (3’); III. An anode (2) having an electron-accepting surface (2’, 2”, 2”’), said anode (2) comprising at least one of the following: said target (3), and said limiting part (4), in at least one of the axial distances in front of the target plane and said active target surface; IV. Magnetic guiding system, which is adapted to provide a magnetic field substantially parallel to at least an outer region of the target surface at the target surface, such that the magnetic field lines are inclined at an acute angle α to the target surface, wherein, An active target surface (3”) is defined in the region of the target surface (3’), where magnetic field lines enter said target surface at an acute angle α ≤ 45°; V. Central axis Z or central plane Z’; Both the limiting part (4) and the anode (2) are made in a closed geometric shape and are electrically isolated from each other and from the target, wherein the minimum distance of the electron acceptance surface (2’, 2”, 2”’) from the active target surface (3”) is defined by at least one of the following: the radial distance Δr from the outer boundary of the target surface (3’) to the inner boundary of the electron acceptance surface 14 , whereby the outer boundary of the target surface (3’) has a radial distance r1 from the middle of the target and the inner boundary of the electron acceptance surface has a radial distance r4 from the middle of the target, and the axial distance h1 from the target surface (3’) to the upper boundary of the limiting part or the axial distance h2 from the target surface (3’) to the lower boundary of the electron acceptance surface (2’, 2”, 2”’). Wherein said magnetic guiding system comprises at least a central magnet and a peripheral annular magnet, said central magnet having a magnetic pole placed in front of the center of the back surface of said target and axially aligned therewith, said peripheral annular magnet having opposite magnetic poles in or below the target plane, said annular magnet being expected to include at least a part of said central magnet and said target; and said magnetic guiding system further comprises a peripheral yoke including said annular magnet, said target and said anode, said peripheral yoke being made of a magnetizable material.

6. The device according to claim 4 or 5, characterized in that Substantially parallel magnetic fields extend from said active target surface (3”) at least to the axial distances (h1, h2) of said limiting part or said electron-accepting surface, and / or at least to a height of 5 - 20 mm above said target surface.

7. The device according to any one of claims 1-5, characterized in that In region A above the active target surface, the intensity of the magnetic flux density B A can be set to 20 - 500 gauss or even higher.

8. The device according to any one of claims 1-5, characterized in that Said limiting part is made of a magnetic or non-magnetic material.

9. The device according to claim 4 or 5, characterized in that Radial distance Δr 14 is 5 - 30 mm.

10. The device according to claim 4 or 5, characterized in that The radial distance r1 of the outer boundary of said target surface from the center of the device is 40 - 110 mm.

11. The device according to claim 4 or 5, characterized in that The axial distances (h1, h2) are 0 - 20 mm.

12. The device according to claim 1 or 5, characterized in that At least one of said central magnet and said annular magnet is an electromagnet or a permanent magnet.

13. The device according to claim 4 or 5, characterized in that The magnetic axis of said annular magnet is inclined upwardly away from the central axis Z or central plane Z’.

14. The device according to claim 1 or 5, characterized in that Said annular magnet comprises two electromagnetic coils C2 and C3, whereby the diameter of C3 is greater than the diameter of C2.

15. The device according to claim 1 or 5, characterized in that The magnetic guidance system further includes a central limiter disposed in or around the center of the target surface, the central limiter being electrically isolated from the target and made of a magnetic material with a Curie temperature T C > 500 °C.

16. The device according to claim 15, characterized in that Said central limiter projects 0 - 20 mm above said target surface.

17. The device according to claim 15, characterized in that Said central limiter is in a plane with said target surface.

18. The device according to claim 17, characterized in that Said limiting part is made of a non-magnetic material.

19. The device according to claim 4 or 5, characterized in that The minimum distance of the electron acceptance surface (2’, 2”, 2”’) from the active target surface (3”) is defined by the radial distance Δr 14 and the axial distance h1 or h2.

20. A vacuum chamber, comprising the cathodic arc evaporation device according to any one of claims 1 - 19.

21. A method for depositing a coating on a substrate in a vacuum chamber, by using a cathodic arc evaporation device according to any one of claims 1-19, by using a magnetic guiding system, by applying a substantially parallel magnetic field to at least an outer region of the target surface (3’), wherein the magnetic field lines enter the target surface at an acute angle α ≤ 45°, thereby forming an active target surface (3”), and igniting and maintaining a cathodic arc discharge on the active target surface, wherein, Region A is laterally bounded by a limiting part at a floating potential, wherein an electron trap is established at least above the vicinity of the target surface within region A.

22. The method according to claim 21, wherein Region B is formed above region A up to an axial distance h3, h3 being given by the maximum axial distance of said electron-accepting surface from said target surface.

23. The method according to claim 21 or 22, characterized in that Region C is formed above regions A and B, wherein the magnetic field is very low or zero, and the atmosphere of region C contains at least one of reactive gas molecules and positively ionized metal ions and positively ionized reactive metal ions.

24. The method according to claim 21 or 22, characterized in that The cathodic arc discharge is maintained at a discharge voltage between 20 V and 50 V.

25. The method according to claim 21 or 22, characterized in that The coating is an AlMeN, AlMeO or AlMeNO compound, where Me represents one or more metals of groups IV, V or VI of the transition metals.

26. A method of producing a coated substrate by the deposition method according to claim 21 or 22.

27. A method for operating the device according to claim 1 or 2, characterized in that During operation of the device in a vacuum chamber, three plasma regions are produced: A first plasma region that contains electrons which, due to the magnetic field lines that leave the front target surface and terminate at the inner surface of the confinement member, cross the magnetic field and cannot approach the anode. A second plasma region where electrons drift to the anode through the magnetic field lines that leave the front target surface and terminate at the electron receiving surface of the anode, and A third plasma region where there are no magnetic field lines that neither leave the front target surface and terminate at the inner surface of the confinement member nor leave the front target surface and terminate at the electron receiving surface.

28. The method according to claim 27, characterized in that: The electron temperature in the first plasma region is between 1 eV and 5 eV, and The electron temperature in the second plasma region and in the third plasma region is between 0.3 eV and 1 eV.

29. The method according to claim 27, wherein The method includes at least one step in which a reactive gas is introduced into the vacuum chamber and the device is operated while the reactive gas is being introduced into the vacuum chamber, where the first plasma region contains more reactive gas ions than the second and third plasma regions, and thus the density of reactive gas ions in the first plasma region is higher than the density of reactive gas ions in the second and third plasma regions.

30. The method according to claim 29, wherein The target or at least the front target surface is made of a metallic material and the reactive gas reacts with the metallic material from the target to produce a layer containing elements from the reactive gas as well as elements from the metallic material.

31. The method according to claim 30, wherein The target contains Ti or Al and the reactive gas contains nitrogen such that the layer produced by the reaction of the reactive gas with the metallic material from the target is a nitride layer containing TiN, AlN or AlTiN.

32. The method according to claim 30, wherein The target contains Ti and Al and the reactive gas contains nitrogen such that the layer produced by the reaction of the reactive gas with the metallic material from the target is a nitride layer containing AlTiN.

33. The method according to claim 31, wherein The target contains Al and Ti, the concentrations of which allow for the synthesis of a coating on a substrate placed in the third plasma region, the coating containing cubic aluminum nitride, the cubic aluminum nitride having an elemental composition of Al x Ti 1-x N, where x is the atomic concentration fraction of Al, and where x is 0.

8.

34. The method according to claim 31, wherein The target contains Al and Ti, the concentrations of which allow for the synthesis of a coating on a substrate placed in the third plasma region, the coating consisting of cubic aluminum nitride having an elemental composition of Al x Ti 1-x N, where x is the atomic concentration fraction of Al and where x is 0.8.

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