Method and device for applying coating

Abstract

The invention relates to a method and a device for applying a coating. The invention also relates to a coated article (60). Articles (60, 62) are provided in a vacuum chamber (12) and a process gas is supplied. Plasma is generated in the vacuum chamber (12) by supplying power to the cathode (30) via application of a cathode voltage VP having a cathode pulse and by atomizing the target (32). A bias VB is applied to the article (60), (62) such that charge carriers of the plasma accelerate toward the article (60), (62) and attach to the surface of the article. In order to achieve advantageous properties of the coating (64) in a controlled manner, the time curve of the bias VB is varied during the application duration D. In the coating (64) of the article (60), (62), the material of the layer (64) contains a rare gas, the concentration of which in the layer (64) varies over the layer thickness.

Description

[0001] The present application is a divisional application of Chinese Patent Application No. 202180043064.8 entitled “Method and apparatus for applying a coating” filed in the International Receiving Office on June 17, 2021 under the Patent Cooperation Treaty as International Application No. PCT / EP2021 / 066499 entering the national phase in the People’s Republic of China as a national application. TECHNICAL FIELD

[0002] The present invention relates to a method and an apparatus for applying a layer to an object. In particular, the present invention relates to coatings produced by cathodic sputtering. BACKGROUND

[0003] It is known to provide objects or parts of objects with a surface coating to improve their mechanical or chemical properties. In particular, for tools and components that are subjected to wear, it is known to provide the functional surface with a coating. In particular, a hard substance layer is referred to as a coating.

[0004] For forming thin coatings, in addition to CVD methods, in particular PVD coating methods are known, in particular cathodic sputtering methods.

[0005] WO 2014 / 063676 A1 describes components with a coating made of chromium, nitrogen and carbon, which is applied in a PVD method with cathodic arc evaporation. In a vacuum chamber, a noble gas is introduced and an initial ion etching is carried out using a bias of -800 V to -1200 V. The bias is then set to a low value and a layer is applied. Argon can be used as noble gas, or neon, which causes lower internal stresses than embedded argon.

[0006] WO 2013 / 045454 A2 describes a method and an apparatus for coating a substrate. A magnetron cathode with a sputter target is arranged in a vacuum chamber. Some cathodes are HIPIMS cathodes, i.e. they are operated with electrical power in the form of voltage pulses by a HIPIMS power source. A bias is applied to the substrate to be coated, which in a preferred embodiment has pulses that are synchronized with the voltage pulses at the cathode, so that the bias is applied during at least a part of the phase characterized by a large number of metal ions generated by the HIPIMS pulses at the cathode. Thus, a lower amount of process gas, e.g. argon, is embedded in the layer compared to a pulse applying a longer or continuous DC bias.

[0007] US 2008 / 0135401 A1 describes an apparatus for sputtering a target at a current density of 0.1 A / cm2to 10 A / cm2on a magnetron cathode to produce a coating on a substrate. The apparatus comprises a power supply connected to the magnetron and a capacitor connected to the power supply. A first switch connects the power supply to the magnetron to charge the magnetron in coordination with a first pulse. A biasing apparatus is connected to the substrate to pre-tune the substrate bias. The biasing can be applied as RF power in a pulsed mode, for example, and can be synchronized with the HIPIMS pulses. A synchronization apparatus synchronizes the frequency and time delay of the first pulses.

[0008] EP 3457428 A1 describes a method and apparatus for processing a semiconductor substrate. A pulse synchronization controller is connected between a pulsed RF bias generator and a HIPIMS generator. A first timing signal is emitted from the pulse synchronization controller to the pulsed RF bias generator and to the HIPIMS generator. Based on the first timing signal, a sputter target and an RF electrode on a substrate carrier are energized and de-energized at the end of the timing signal. A second timing signal is emitted from the pulse synchronization controller to the pulsed RF bias generator and based on the second timing signal the electrode is energized and de-energized without energizing the target. SUMMARY

[0009] It can be considered an object to propose a method and apparatus for applying a layer to an object, in which particularly advantageous layer properties can be realized in a controlled manner.

[0010] The object is solved by the method according to claim 1 and the apparatus according to claim 11. The dependent claims relate to advantageous embodiments of the invention.

[0011] The inventors started from the consideration that when a layer is produced by sputtering through a cathode while a pulsed voltage is applied to the cathode, the layer composition can be predetermined differently by the time profile of the bias. Depending on whether the bias is applied as a DC voltage or as a pulsed voltage, and in the case where the pulsed voltage plays a role in synchronization with the pulse time at the cathode, the prevailing component in the plasma at different points in time can be selected in a controlled manner and used for forming the layer. In particular when the time profile of the gas ions present in the plasma differs from the time profile of the metal ions, as in the HIPIMS method, the ratio of the gas ions to the metal ions can thus be set in a controlled manner by the time course of the bias.

[0012] In contrast to the known teaching of achieving the desired composition of the layer by keeping the time course of the bias the same over the duration of the coating, the inventors have proposed achieving different compositions of the layer over the layer thickness in a controlled manner by varying the time course of the bias during the duration of the coating. This is because, in contrast to the previous understanding that gas ions in the layer are generally undesirable and must always be minimized, the inventors have recognized that depending on the desired application of the object, the layer structure, the general layer properties, the type of substrate, etc., a certain proportion of gas ions can actually be advantageous in certain regions of the layer, for example according to the current case, on the layer surface, in the interface region, or in the middle region of the layer, as long as the proportion varies over the layer thickness and can be set in a controlled manner.

[0013] The gas ions considered are primarily noble gas ions which are used as process gas in the vacuum chamber, in particular argon.

[0014] It has thus been shown that at a relatively high proportion of argon, layers can be achieved which have a very high hardness and high internal stress, i.e. hard and brittle layers, whereas layers without argon or with a lower proportion of argon are rather ductile. Surprisingly, it has been shown that for some applications, for example hard machining, layers with a high internal stress at least on the layer surface achieve particularly good results, for example high cutting performance. On the other hand, layers which are rather ductile due to a lower proportion of argon have very advantageous properties, for example in the interface region, for example for achieving good adhesion to the substrate, or depending on the intended use of the object, for example as a tool, furthermore in the region of the layer surface, for example in terms of tribological properties or for run-in behavior.

[0015] In order to be able to set the desired layer formation and thus the resulting properties in a controlled manner, the method for applying a layer to an object according to the invention provides that the object is arranged in a vacuum chamber and a plasma is generated by operating one or more cathodes by supplying a process gas, for example a noble gas, preferably argon, and sputtering at least one target. The cathode is preferably a magnetron cathode, in particular a non-equilibrium magnetron, which is provided with a target made of the target material, preferably made of one or more metals, so that the material is sputtered to cause the plasma to contain gas ions and metal ions (magnetron sputtering).

[0016] According to the application, at least one cathode is not operated with a constant voltage, but with a pulsed cathode voltage having cathode pulses which are spaced in time. Preferably, one or more cathodes are operated according to the HIPIMS method (High Power Impulse Magnetron Sputtering), in which short cathode pulses with high voltages are applied and very high peak powers are achieved. This HIPIMS method is understood to mean operation particularly within the parameter ranges mentioned below as part of possible exemplary embodiments.

[0017] During at least a part of the coating duration, a bias voltage is applied to the object to be coated, so that the charge carriers of the plasma are accelerated in the direction of the object and adhere as a layer to its surface. The method according to the application is characterized in that the time course of the bias voltage is varied during the coating duration.

[0018] In the case of a DC voltage, the time course of the bias voltage can be at least partially a constant time course or a variable time course, in particular a pulsed time course. In the case of a periodic time course which varies continuously in time, the variation of the time course during the coating duration can be a variation in frequency or phase position. According to the application, the variation of the time course comprises a synchronization with the duration and / or the time of the cathode pulses, which is different at various points in time or intervals during the coating duration. As explained, the composition of the layer can be influenced by the time course of the bias voltage: while, for example, under a constant bias voltage (DC), all ions of the plasma are uniformly accelerated in the direction of the object by a pulsed bias voltage, the bias pulses of which are time-synchronized with the cathode pulses, i.e. are applied with the same frequency and a fixed phase relationship, the ion species which are present in the plasma at the selected points in time can be selected individually according to the duration and the time position of the pulses and accelerated in the direction of the article.

[0019] The bias voltage with a variable time course during the coating duration can thus have a pulsed profile in part or in whole, wherein the synchronization with the cathode pulses can vary during the coating duration. Likewise, the time course of the bias voltage can be a DC voltage profile in one or more time intervals, while a pulsed time course can be applied in other time intervals.

[0020] According to the invention, the time profile of the bias is pulsed at least during a part of the coating duration, i.e. the bias comprises bias pulses, which are applied in synchronization with the cathode pulses, i.e. with the same (or respective, alternatively multiple) frequency and fixed phase relationship. The pulses are preferably DC voltage pulses, i.e. a bias which is preferably at least essentially constant during the pulse time is applied. The time of the bias pulses effective with respect to the cathode pulses can thus be characterized by the respective pulse duration and by the time position with respect to the cathode pulses, i.e. the time difference at which the respective pulse starts before or respectively after the start of the cathode pulse, wherein the time difference can also possibly be zero. The variation of the time profile of the bias according to the invention during the coating duration is realized in the form of a variation of the duration and / or synchronization of the bias pulses with respect to the cathode pulses, wherein the variation of the duration and / or synchronization can be abrupt or continuous, e.g. in the form of a ramp curve.

[0021] In each case, due to the variation of the time profile of the bias, different layer growth conditions are produced during the coating duration at different points in time or intervals, so that with the progression of the layer growth a layer is obtained which varies in structure and / or composition over the layer thickness. Particularly suitable properties can thus be realized in different regions of the layer, e.g. good adhesion to the substrate, a hard or smooth surface, etc.

[0022] The device according to the invention is suitable for carrying out the method according to the invention. The device comprises a vacuum chamber with a carrier for the object, a process gas supply and a cathode with a target. The cathode is connected to a cathode power supply, and the object or respectively its carrier is connected to a controllable bias power supply. By means of the cathode power supply, preferably a HIPIMS power supply, a cathode voltage with cathode pulses is produced, and by means of the bias power supply a bias is produced. A controller is provided by means of which the bias power supply can be controlled such that the time profile of the bias is varied during the coating duration.

[0023] The controller can in particular be a programmable controller by means of which, preferably in addition to the bias power supply, other functions of the coating device can be controlled in a time-dependent manner in accordance with a coating program, in particular the power supply of the respective cathodes and the supply of process gas and / or reactive gas.

[0024] The coated object can be produced, for example, by means of the method according to the invention and / or the device according to the invention. The object comprises a substrate, which can be a base body made of, for example, steel, in particular HSS or CrMo steel, carbide, a ceramic material or cBN (cubic boron nitride). The substrate can be, for example, a tool, in particular a tool for machining, e.g. a drill, a milling cutter, an indexable insert, a punching or stamping tool, etc.

[0025] A layer made of a layer material applied by cathode sputtering is arranged on a surface of a substrate. The layer material according to the application comprises at least one element from a first group comprising aluminum (Al), silicon (Si), yttrium (Y), and elements from group 4 to 6 according to the IUPAC (1988) periodic table, and at least one element from a second group comprising nitrogen (N), oxygen (O), carbon (C) and boron (B). The selection of the elements of the first group and the second group can be referred to as the material system. Preferred material systems mainly comprise nitrogen and one or more elements of the first group, in particular titanium (Ti), aluminum (Al), silicon (Si) and / or chromium (Cr). The material system is shown here by naming the individual elements with a hyphen, i.e. without indicating a chemical bond. Particularly preferred layer systems are aluminum-titanium-nitride (Al-Ti-N), titanium-nitride (Ti-N), titanium-aluminum-silicon-nitride (Ti-Al-Si-N), titanium-aluminum-chromium-silicon-nitride (Ti-Al-Cr-Si-N), titanium-boride (TiB2), titanium-carbonitride (Ti-C-N), titanium-aluminum-carbonitride (Al-Ti-C-N), chromium-nitride (Cr-N), zirconium-nitride (Zr-N), and titanium-carbide (Ti-C). The indicated elements of the respective material system are preferably listed in the order of their relative atomic mass.

[0026] The layer material also comprises a proportion of a noble gas, preferably argon. Here, in the object according to the application, the concentration of the noble gas in the layer varies over the layer thickness, i.e. depending on the distance of the respective observation position of the layer from the layer surface or respectively the substrate, different concentrations of the noble gas within the layer arise at different positions of the layer.

[0027] The noble gas is the process gas used when applying the layer by cathode sputtering, preferably argon. As described above, in particular by a suitable selection of the time course of the bias voltage, the proportion of the process gas in the layer can be controlled in such a way that the desired concentration profile can be set in a controlled manner over the layer thickness.

[0028] An advantageous development of the method according to the application in particular relates to the type of variation of the time course of the bias voltage. Advantageously, as explained, this can be achieved by a suitable application of the proportion of the process gas in the layer depending on the time course of the bias voltage. By varying the time course during the coating duration, the desired proportion of the process gas in the layer varying over the layer thickness can be achieved in this way.

[0029] For the method according to the application and for the apparatus according to the application, various embodiments are possible. Thus, the bias voltage preferably has a pulsed time course during at least a first time interval of the coating duration, i.e. it comprises voltage pulses which are referred to here as "bias pulses". The bias pulses are preferably synchronized with the cathode pulses, i.e. have the same frequency (or alternatively one of the frequencies is a multiple of the other, which also indicates synchronization). While synchronization in which the bias pulses and the cathode pulses always start at the same time is also possible, as is synchronization of the introduction times of the bias pulses, the bias pulses are preferably delayed by a lag time with respect to the cathode pulses, i.e. the start of the bias pulses is temporally after the start of the cathode pulses. The lag time can be in the range from 5 to 150 µs, for example, and is selected depending on the ions which are preferred in each case. The duration of the bias pulses is in the range from 30 to 150 µs, preferably 50 to 100 µs, for example.

[0030] During a further time interval, which can be temporally before or after the first time interval during the coating duration, it is also possible for there to be a time interval between them, the bias voltage preferably has a time course which deviates from the first time interval. This can be a pulsed profile, for example, as in the first time interval but with a deviating phase relationship, in particular a deviating lag time. Equally, the deviating time course in the further time interval can also be a constant DC voltage (DC bias). In contrast to a pulsed bias in which the ions can be selectively selected by appropriate synchronization with the cathode pulses so that, for example, a higher proportion of metal ions can be selected in a controlled manner, by means of a DC bias all of the ions of the plasma are accelerated in the direction towards the substrate without exception and form a coating with a relatively high proportion of process gas.

[0031] According to one advantageous embodiment, the time course of the bias voltage comprises, during a first time interval, bias pulses which are synchronized with the cathode pulses and occur with a first lag time with respect to the cathode pulses, and, during a second time interval, bias pulses which are also synchronized with the cathode pulses but in this case occur with a second lag time which deviates from the first lag time with respect to the cathode pulses. The second time interval is preferably temporally after the first time interval and can follow the first time interval immediately in time, or there can be a time interval between the time intervals. The first time interval can be at the start of the coating duration.

[0032] The time interval can be short, for example, a few minutes or more, up to several hours. For example, the duration of the first time interval and / or the second time interval can be chosen such that during this time the layer grows a small amount, for example 0.1 pm, but embodiments in which the layer grows up to 3 pm during the first time interval and / or the second time interval are also possible. In order to achieve individual layers in the layer having a layer thickness in the nanometer range, meaning for example 5 nm to 100 nm, preferably 5 nm to 50 nm, the time interval can be chosen to be very short, for example 20 seconds to 360 seconds, preferably 20 seconds to 180 seconds. In order to achieve individual layers in the micrometer range, meaning for example 0.5 pm to 10 pm, preferably 0.5 pm to 2 pm, the time interval can be chosen for example in the range of 50 minutes to 1200 minutes, preferably 50 minutes to 360 minutes.

[0033] For example, one of the lag times can be in a range in which a relatively high proportion of metal ions and a comparatively low proportion of gas ions are present in the plasma, for example in the range of 30 ps to 80 ps, while the other lag times can be chosen such that a relatively high proportion of gas ions is present in the plasma, for example 0 ps to 20 ps or more than 90 ps. For example, the lag time in the first time interval, which is temporally earlier in the coating duration, can be shorter, such that a larger proportion of metal ions is used to form the layer, while the lag time in the second time interval, which is temporally later in the coating duration, is longer, such that a higher proportion of gas ions is incorporated into the layer.

[0034] Preferably, during at least one time period or during the entire coating duration, a synchronized bias voltage pulse having a lag time relative to the cathode pulse is thus generated, wherein the lag time varies. The variation of the lag time can occur suddenly, stepwise, or also (slightly) continuously.

[0035] In order to form a transition layer having a gradual change in layer properties, the variation of the lag time, for example stepwise or continuously, from a first value to a second value, wherein the first value is higher or lower than the first value, can occur during a transition time interval, which can include a portion of the coating duration or the entire coating duration. The progression can for example be linear in the form of a ramp, but equally, a deviating progression is possible. The duration of the transition time interval during which the variation occurs can be chosen such that during this time the layer grows 0.5 pm to 20 pm.

[0036] In other preferred embodiments, the variation can oscillate stepwise or continuously between two values over a part of the coating duration or the entire coating duration, such that, for example, a multi-layer structure is formed in the layer, preferably with more than 2 individual layers. Here, the lag time can assume a first value during a first switching subinterval and a second value during a second switching subinterval, which deviates from the first value. The first switching subinterval and the second switching subinterval can follow each other one or more times during the switching time interval. In doing so, the duration of the first switching subinterval and / or the second switching subinterval can each be chosen such that during this time, a layer grows between 5 nm and 2 pm. Preferred examples are a thickness of the individual layers of, for example, 5 nm to 100 nm, preferably 5 nm to 50 nm, for nano-layer structures, and a thickness of the individual layers in the range of, for example, 0.1 pm to 2 pm, for example, with a total of 6 to 40 individual layers in the layer, for multi-layer structures.

[0037] Further preferred embodiments relate to a device according to the application. The device thus preferably comprises one or more HIPIMS cathodes, i.e. cathodes connected to a HIPIMS power source. The HIPIMS power source preferably comprises a capacitor for supplying electrical power for the HIPIMS pulses and a charging device for the capacitor. The power source is preferably power-regulated. A plurality of cathodes arranged in a vacuum chamber can be equipped with targets of different compositions. Thus, layers of different compositions can be deposited on top of each other in a continuous process without interrupting the vacuum by switching on or off (or correspondingly increasing / decreasing the power) the connected power sources. This is preferably carried out by a controller. BRIEF DESCRIPTION OF DRAWINGS

[0038] In the following, embodiments will be further described with reference to the attached drawings. The drawings show:

[0039] Figure 1 Schematic diagram of a coating system with a circuit;

[0040] Figure 2 Diagram with the time progression of the cathode pulses and the bias pulses;

[0041] Figure 3 Diagram representing the amount and type of ions in the plasma in chronological order from the triggering of the cathode pulses;

[0042] Figures 4a to 4d Different time courses of the bias voltage and the amount and type of ions in the plasma according to Figure 3 the diagram according to the application.

[0043] Figure 5 One exemplary embodiment of a coating in a schematic diagram of a surface region of a coated object;

[0044] Figure 6a 、 Figure 6b a diagram of the progression of a coating over time and a first exemplary embodiment of a coating in a schematic representation of a surface area of ​​a coated object;

[0045] Figure 7a 、 Figure 7b a second exemplary embodiment of a coating in a diagram of the progression of a coating over time and in a schematic representation of a surface area of ​​a coated object;

[0046] Figure 8a 、 Figure 8b a third exemplary embodiment of a coating in a diagram of the progression of a coating over time and in a schematic representation of a surface area of ​​a coated object;

[0047] Figure 9a 、 Figure 9b a fourth exemplary embodiment of a coating in a diagram of the progression of a coating over time and in a schematic representation of a surface area of ​​a coated object;

[0048] Figure 10a 、 Figure 10b a fifth exemplary embodiment of a coating in a diagram of the progression of a coating over time and in a schematic representation of a surface area of ​​a coated object;

[0049] Figure 11a 、 Figure 11b a sixth exemplary embodiment of a coating in a diagram of the progression of a coating over time and in a schematic representation of a surface area of ​​a coated object;

[0050] Figure 12 An exemplary embodiment of a tool having a coating. DETAILED DESCRIPTION

[0051] Figure 1 1 shows a schematic diagram of a coating system 10. The coating system 10 comprises a vacuum chamber 12, shown schematically here from above, with a vacuum system 14, by means of which a vacuum can be generated within the vacuum chamber 12. The vacuum chamber 12 also has a process gas supply 16 and a reactive gas supply 18, by means of which a process gas (in a preferred embodiment, argon) and a reactive gas (for example nitrogen) can be introduced into the vacuum chamber 12.

[0052] A rotating substrate table 20 with a planetary rotating substrate carrier 22 is positioned within the vacuum chamber 12. The substrate 60 to be coated, i.e. a base body, such as a tool (see Figure 12 ) are each arranged on a substrate carrier 22 and electrically connected to the substrate carrier 22 and the substrate stage 20.

[0053] Also provided within the vacuum chamber 10 are magnetron cathodes 30, 34 and the anode 28. The magnetron cathodes 30, 34 each include an unbalanced magnetic system (not shown) and a plate-shaped sputtering target 32, 36.

[0054] The magnetron cathodes 30 , 34 , substrate table 20 , and anode 28 are each connected from outside the vacuum chamber 12 to external circuitry of the coating system 10 by electrical feedthroughs through the walls of the vacuum chamber 12 .

[0055] In the example shown, the magnetron cathode 34 is wired as a DC cathode, i.e., is connected to a DC power supply 44, which supplies a DC voltage to the magnetron cathode 34 relative to the anode 28. The anode 28 is connected to an anode power supply 46, which supplies a DC voltage to the anode 28 relative to the conductive wall of the vacuum chamber 12. The magnetron cathode 30 is wired as a HIPIMS cathode, i.e., is electrically connected to a HIPIMS power supply 40, which applies a pulsed voltage V to the magnetron cathode 30 relative to the chamber wall. P The substrate stage 20 is connected to a bias power supply 42 that supplies a bias voltage V to the substrate stage 20 relative to the anode 28. B .

[0056] The coating system 10 is equipped with a controller 48, which controls the bias power supply 42 and the HIPIMS power supply 40, as will be described in detail below. In addition, the controller 48 controls the entire process, i.e., it also controls the vacuum system, the rotation drive of the substrate table 20, the supply of process gases and reactive gases, and all other power supplies 44, 46. The controller is programmable, i.e., it includes a memory for the coating program, which specifies the process and method steps described below.

[0057] It should be noted that the arrangement of the electrodes of the circuit and coating system 10 as shown should be understood as purely exemplary. In alternative embodiments, for example, the HIPIMS cathode 30 can be connected relative to the anode 28, or, for example, the anode 28 can be omitted and the chamber wall can be wired as an anode for all cathodes and for the substrate table 20. Multiple DC cathodes 34 can be provided, or no DC cathodes 34 can be provided. In addition to the HIPIMS cathode 30, further HIPIMS cathodes can be provided in the vacuum chamber 12, each connected to its own HIPIMS power supply. The cathodes 30, 34 can be equipped with targets 32, 36 of the same or different compositions.

[0058] The HIPIMS power supply 40 supplies power to the HIPIMS cathode 30 according to the HIPIMS method, that is, the supplied voltage V P , current I P And the transient power therewith has a time course in the form of short, very high pulses.

[0059] As an example, the period duration T of such a periodic time course is shown in Figure 2 The voltage V P applied to the HIPIMS cathode 30 is negative. The time course comprises an approximately rectangular voltage pulse 50 of the pulse duration T P For the remainder of the period duration T, no voltage is applied.

[0060] By way of example, the following preferred parameters for the HIPIMS method are mentioned. The voltage V P is applied periodically at a frequency of, for example, 100 Hz to 10,000 Hz, preferably 500 Hz to 4000 Hz, such that the period duration T is preferably in the range of 250 µs to 2000 µs. The pulse duration T P is preferably low, for example shorter than 200 µs, preferably 40 µs to 100 µs. Preferably, the duty cycle T P / T is in the range of 1 % to 35 %, preferably 10 % to 30 %, particularly preferably 20 % to 28 %. The operation of the HIPIMS cathode 30 is preferably carried out in a power-regulated manner, for example at values of 3 kW to 20 kW per HIPIMS cathode 30, preferably 10 kW to 16 kW per cathode. The peak current generated during the pulse relative to the front side of the target 32 is preferably 0.4 A / cm² to 2 A / cm², further preferably 0.5 A / cm² to 0.8 A / cm².

[0061] When the coating system 10 is operated to apply a coating 64 to the functional area 62 of the substrate 60, as Figure 12 is shown by way of example in Fig. 2, for a milling tool 66, the substrate 60 to be coated is arranged on the substrate carrier 22 within the vacuum chamber 12. A vacuum is generated in the interior of the vacuum chamber 12. After an optional preparation step (for example, heating, surface treatment of the substrate 60 by ion etching, sputter cleaning of the cathodes 30, 34, etc.), a plasma is generated by operating one or more HIPIMS cathodes 30 (and optionally simultaneously operating one or more DC cathodes 34) while sputtering the targets 32, 36. The components of the plasma adhere themselves to the surface of the substrate 60 and form the layer 64, wherein the positively charged ions of the plasma are accelerated in the direction towards the substrate surface by the negative bias voltage V B .

[0062] Figure 3It is shown by way of example for a HIPIMS cathode 30 with a target 32 made of titanium and aluminum and with simultaneous supply of argon as process gas that the ions measured in the plasma in time resolution after the start of the cathode pulse 50 at t = 0 μβ. As shown, the plasma contains various metal ions and gas ions, wherein, however, the different species show a time course that deviates from one another. In this way, the number of argon ions increases relatively quickly up to a local maximum at about 35 μβ, then decreases and increases again significantly in a later course starting at about t = 90 μβ. The metal ions increase somewhat more slowly, reach a maximum approximately in the range of t = 50 μβ to 60 μβ and then decrease again.

[0063] As shown schematically, three time periods 54, 56, 58 can be defined, wherein in a first time period 54 (about 0 μβ to 40 μβ) gas ions prevail, in a subsequent second time period 56 (from about 40 μβ to 100 μβ) metal ions prevail, and in a subsequent third time period 58 (from about 100 μβ) gas ions prevail significantly.

[0064] By means of a negative bias V B The positive gas ions and metal ions of the plasma are accelerated in the direction toward the surface of the substrate 60 and thus become part of the coating 64 that adheres there itself. In the case of a DC bias, i.e. a continuous DC voltage as bias V B , all ions are selected without exception for layer formation. In Figure 4d , this is shown by way of example, wherein a bias V B is applied constantly.

[0065] Instead of a DC bias, the bias V B can be applied with a pulse time course that is synchronized with the time course of the voltage V P at the HIPIMS cathode 30. Such a pulse time course of the bias V B is shown by way of example in Figure 2 . The bias V B has a rectangular pulse 52 (bias pulse) applied during the bias pulse duration T B during the cathode pulse 50. In this case, the bias pulse 52 is delayed in time relative to the cathode pulse by a delay time T D .

[0066] By appropriate selection of the time synchronization between the cathode pulse 50 and the bias pulse 52, i.e. in particular by appropriate selection of the bias pulse duration T B and the delay time T DA selection between gas ions and metal ions present in the plasma at each point in time can be made.

[0067] For example, Figure 4a The effect of a pre-timing of the time course of the bias pulses 52 is shown, wherein the bias pulse duration T B is about 60 µs and the lag time T D is about 40 µs. Thus, the bias pulses 52 are synchronized with the second time period 56, in which the metal ions are dominant. By pre-timing the bias V B in this time course, a coating 64 with a very low proportion of argon is produced.

[0068] In an experiment using a HIPIMS target 32 made of titanium, silicon and aluminum and supplying nitrogen gas as a reactive gas to deposit a coating 64 made of the Ti-Al-Si-N material system, wherein the time course of the bias V B is shown in Figure 4a , a proportion of argon of 0.03 atom% in the coating 64 is produced. The coating 64 has an internal stress of -1.6 GPa and a hardness of 26 GPa.

[0069] In comparison, in the case of an otherwise identical configuration and process control with the application of a DC bias Figure 4d , a proportion of argon of 0.12 atom% in the coating 64, an internal stress of -5.3 GPa and a hardness of 30 GPa are shown.

[0070] As a further example of a possible time course of the bias V B , Figure 4b a time course with a bias pulse duration T B of about 60 µs and a lag time T D of about 100 µs is shown, so that the bias pulses 52 are synchronized with the third time period 58, in which the gas ions are dominant. By pre-timing the bias V B in this time course, a coating 64 with a high proportion of argon is thus produced.

[0071] As a further example, Figure 4c the effect of a bias V B with a bias pulse duration T D of about 100 µs and a lag time T B of about 20 µs is shown. In each case, the bias pulses 52 completely cover the second time period 56 and partially cover the first time period 54 and the third time period 58. By pre-timing the bias V B in this time course, a coating 64 with a medium proportion of argon is produced.

[0072] Thus, by pre-timing the bias VB The time course of the bias voltage V Figure 4a ) can influence the layer composition and, in particular, can set the proportion of argon in a controlled manner to a value between a minimum proportion ( Figure 4b ) and a maximum proportion (

[0073] The layer properties are thus significantly influenced, in particular the internal stresses in the coating 64 and its hardness.

[0074] By means of the coating system 10, a coating 64 is applied to each substrate 60. These coatings grow with the progressing coating duration D such that they each have a thickness S from the surface of the substrate 60. By means of the controller 48, both the HIPIMS power supply 40 and the bias power supply 42 are controlled during the coating duration D such that, in different time intervals during the coating duration D, bias voltages V B with a time course that deviates from one another. This achieves a varying composition of the coating 64 over the layer thickness S, i.e. a respective proportion of argon that differs depending on the time course set in each case.

[0075] In the case of synchronization of the bias pulses 52 with the cathode pulses 50 ( Figure 2 ), the time course can be characterized by a lag time T D and a bias pulse duration T B . By way of example, the bias pulse duration T B may thus be set as a fixed value of, for example, 60 ps, while the lag time T D varies depending on the coating duration D.

[0076] One exemplary embodiment is explained below with reference to Figure 5 in which a bilayer coating 64 is deposited on the substrate 62 by means of a synchronous change in the bias voltage VB during the coating duration.

[0077] For the application of the coating 64, the object 60 to be coated made of the substrate material 62 is first positioned on the substrate carrier 22 within the vacuum chamber 12, for example a double-edged ball-end mill with a diameter of 6 mm made of carbide with a cobalt content of 6 atomic percent (WC / Co).

[0078] The coating system 10 is equipped with four HIPIMS cathodes 30 arranged around the substrate table 20. Two cathodes 30 arranged next to one another are each equipped with a target 32 made of a titanium aluminum material (for example, 60 atomic percent Ti, 40 atomic percent Al), and the two remaining electrodes are equipped with a target 32 made of a titanium silicon material (for example, 80 atomic percent Ti, 20 atomic percent Si).

[0079] A vacuum is generated by operating the vacuum system 14. The interior of the vacuum chamber 12 is heated. While the cathodes 30 and 34 are in operation, the surface of the substrate 60 is cleaned by gas ion etching. The targets 32 and 36 are prepared by sputter cleaning.

[0080] At the start of coating, a first layer 80a is first deposited on the substrate 60 during a first time interval. For this purpose, two cathodes 30 having Al-Ti targets are operated, each with a cathode power of 12 kW, while the two remaining cathodes 30 having Ti-Si targets are initially not operated. Power is supplied in the form of HIPIMS cathode pulses 50 with a frequency of 4000 Hz and a pulse length of 70 μs. A bias voltage V is thus applied to the substrate 60 via the substrate stage 20 and the substrate carrier 22. B With a bias pulse of 60 V and a bias pulse duration of 40 µs, T B Bias voltage V B The bias pulse 52 is synchronized with the cathode pulse 50 but with a 40µs lag time T D occur.

[0081] The first layer 80a is deposited at a layer rate of about 1 μm / hour so that it reaches a thickness of 1.5 μm after a first time interval of 1.5 hours. B With a 40µs hysteresis time T D , whereby the metal ions are selected in a controlled manner to form the coating 64, while the argon ions which are generated increasingly in the later time curves of the respective pulses are present only to a low extent (cf. Figure 4a ). The argon content of the coating layer 64 in the first layer 80a is less than or equal to 0.03 atomic %, so that an internal stress of less than or equal to -1.6 GPa is generated.

[0082] Subsequently, in a second time interval, a second layer 80b was deposited onto the 1.5 μm thick first layer 80a. To this end, while further coating was performed, the controller 48 controlled the power supply to the two cathodes 30 having Ti-Si targets so that each operated at a cathode power of 12 kW, while the remaining two cathodes 30 having Al-Ti targets were not operated. The HIPIMS parameters for the power supply in the second time interval were the same as those in the first time interval, namely, a frequency of 4000 Hz and a pulse length of 70 μs.

[0083] However, during the transition from the first time interval to the second time interval, the bias voltage V B The time course of ΔV is changed so that it is not applied in a pulsed time course in the second time interval but is applied as a continuous DC voltage, so that the coating 64 also contains a considerable amount of argon ions.

[0084] The second layer 80b is deposited with a layer rate of about 1 pm / hour so that it reaches a thickness of 1.5 pm after the duration of a second time interval of 1.5 hours. Due to the non-pulsed bias V B The argon content of the coating 64 in the second layer 80b is thus at least 0.12 atom% so that an internal stress of at least 5.3 GPa is generated.

[0085] The layer 64 is thus bi-layered, wherein the first layer 80a realizes a very good layer adhesion due to the low internal stress and the higher ductility, while the outer second layer 80b ensures a hard, smooth surface of the coated object 60. A ball-end-mill coated in this way is suitable for milling high-carbon steel of more than 60 HRC without emulsion.

[0086] In the following, further separate exemplary embodiments are shown in which a coating 164, 264, 364, 464, 564, 664 is generated on a substrate 62, wherein in each case the composition and the properties of the coating are changed by a change of the time course during the coating duration, in particular by changing the synchronization of the bias V B In the following description, all further details of the coating procedure, such as the equipping of the targets as well as the specific parameters and durations, will not be mentioned, since it is mainly about showing the main embodiments, which can be applied to different material systems and with different parameters.

[0087] Figure 6a 、 Figure 6b A first exemplary embodiment of a coated object 166 with a bi-layered coating 164 is shown.

[0088] When depositing the coating 164, in each case a bias voltage V B is applied with a pulsed time course of bias pulses 52 synchronized with cathode pulses 50. However, as Figure 6a is shown, the synchronization is changed during the coating duration D. Thus, in a first time interval 170a, the lag time T D is initially 40 ps and in a subsequent second time interval 170b 110 ps.

[0089] Figure 6bA cross-section through the respective coated object 166 is schematically shown, with the resulting coating 164 on the substrate 62. The coating 164 comprises a first layer 180a with a low proportion of argon on the substrate 62 and a second layer 180b with a higher proportion of argon on top of the first layer 180a. The first layer 180a is rather ductile and has a low internal stress due to the lower proportion of argon, so that it can be used as a good adhesive to the substrate 62. The second outer layer 180b has a high hardness due to the higher proportion of argon. Such layers have proven to be particularly suitable for tools that are required for machining applications, such as for example for drilling and milling tools, such as end mills, ball end mills, and indexable inserts.

[0090] Figure 7a 、 Figure 7b A second exemplary embodiment with a process control that is essentially opposite to the first exemplary embodiment is schematically shown. In the second exemplary embodiment, the lag time T D is changed from initially 110 µs in a first time interval 270a to 40 µs in a subsequent second time interval 270b. The resulting coating 264 of the coated object 260 has a first layer 280a with a high proportion of argon and a second layer 280b with a lower proportion of argon.

[0091] Such a coating 264 can be advantageous especially for coated objects 260 that are provided for tribological applications. The first layer 280b serves as a hard base layer with internal stress. The second layer 280b serves as a top layer on top of the first layer 280b, which has good running-in properties due to the higher ductility. Possible applications can include thread cutting taps, formed taps, drills, and punching and stamping tools.

[0092] Figure 8a 、 Figure 8b A third exemplary embodiment is schematically shown. The third exemplary embodiment shows a coating duration D of 60 s and a lag time T D is changed stepwise in three time intervals 370a, 370b, 370c. In this case, the lag time T D is increased stepwise as in the first exemplary embodiment. The resulting coating 364 of the coated object 360 has a first layer 380a with a low proportion of argon, a second layer 380b with a medium proportion of argon, and a third outer layer 380c with a high proportion of argon.

[0093] Figure 9a 、 Figure 9b A fourth exemplary embodiment is shown, in which the lag time T DAs a result, the argon content also changes not stepwise but gradually over the coating duration, here, for example, in the form of a linearly increasing ramp. Consequently, the resulting coating 464 of the coated object 460 exhibits an increasing argon content moving from the substrate 62 toward the surface. Consequently, the coating 464 exhibits only low internal stresses in the interface region with the substrate 62, which promotes adhesion. In the surface region, the coating 464 exhibits a high hardness, making it particularly advantageous for use in tools for machining applications.

[0094] exist Figure 10a 、 Figure 10b , a fifth exemplary embodiment is shown with a process control opposite to that of the fourth exemplary embodiment, i.e., a lag time T D The argon content in the coating 564 of the coated object 560 decreases constantly over the coating duration D, here in the form of a linearly decreasing slope.

[0095] Figure 11a 、 Figure 11b A sixth exemplary embodiment is shown, wherein the lag time T during the coating duration D D Repeatedly changes suddenly one after another in the first time interval 670a and the second time interval 670b. During the first time interval 670a, the lag time T D is 40µs, and during the second time interval 670b, the lag time T D is 110µs.

[0096] As a result, the resulting coating 664 of the coated object 660 has first layers 680a with a low argon content and second layers 680b with a higher argon content, alternating one after another in the direction of the layer thickness S. The layer directly disposed on the substrate 62 in the interface region is the first layer 680a with low internal stress, which promotes adhesion. The outermost layer in the surface region is the second layer 680b with a high hardness.

[0097] The thickness of layers 680a, 680b is preset at a constant layer rate by the duration of time intervals 670a, 670b. By selecting the duration of time intervals 670a, 670b and the number of switching operations, a multilayer coating 664 can be produced, wherein, for example, the thickness of individual layers 680a, 680b is 0.1 µm to 2 µm. Similarly, by switching time intervals 670a, 670b more quickly, a nanolayer coating 664 can be produced, wherein the thickness of individual layers 680a, 680b is 5 nm to 50 nm, for example.

[0098] Table 1 below shows other exemplary embodiments of the coating:

[0099] Number Layer material Layer structure Distribution of Ar concentration over layer thickness Layer thickness 1 Al-Ti-N Single layer, gradual Slope increase up to surface 0.5 pm to 20 pm 2 [Ti-B2] Single layer, gradual Slope increase up to surface 0.5 pm to 5 pm 3 Ti-C-N Single layer, gradual Slope decrease up to surface 0.5 pm to 3 pm 4 Ti-N Single layer, gradual Slope increase up to surface 0.1 pm to 2 pm 5 First layer Al-Ti-N second layer Ti-Al-C-N Double layer, stepwise Stepwise decrease: first layer with much argon, second layer with little argon First layer 0.5 pm to 3 pm second layer 0.1 pm to 1.5 pm 6 First layer Al-Ti-N second layer Ti-C-N Double layer, stepwise Stepwise decrease: first layer with much argon, second layer with little argon First layer 0.5 pm to 3 pm second layer 0.1 pm to 1.5 pm 7 First layer Al-Ti-N second layer Ti-C Double layer, stepwise Stepwise decrease: first layer with much argon, second layer with little argon First layer 0.5 pm to 3 pm second layer 0.1 pm to 1.5 pm 8 As in example 5, 6 or 7 Double layer, stepwise, gradual transition Gradual decrease: first layer with much argon, second layer with gradual decrease to little argon First layer 0.5 pm to 3 pm second layer 0.1 pm to 1.5 pm 9 First layer Al-Ti-N second layer Ti-Si-N Double layer, stepwise Stepwise increase: first layer with little argon, second layer with much argon First layer 0.5 pm to 10 pm second layer 0.1 pm to 20 pm 10 First layer Al-Ti-N second layer Ti-Al-Si-N Double layer, stepwise Stepwise increase: first layer with little argon, second layer with much argon First layer 0.5 pm to 10 pm second layer 0.1 pm to 20 pm 11 First layer Al-Ti-N second layer Ti-Al-Cr-Si-N Double layer, stepwise Stepwise increase: first layer with little argon, second layer with much argon First layer 0.5 pm to 10 pm second layer 0.1 pm to 20 pm 12 First layer Al-Ti-N second layer Ti-N Double layer, stepwise Stepwise increase: first layer with little argon, second layer with much argon First layer 0.5 pm to 10 pm second layer 0.1 pm to 2 pm 13 First layer Al-Ti-N second layer Zr-N Double layer, stepwise Stepwise increase: first layer with little argon, second layer with much argon First layer 0.5 pm to 10 pm second layer 0.1 pm to 2 pm 14 First layer Al-Ti-N second layer Ti-N or Zr-N or C Double layer, stepwise Stepwise increase: first layer low argon, second layer high argon First layer 0.5 µm to 10 µm second layer 0.1 µm to 2 µm 15 First layer Al-Ti-N second layer Ti-Al-Cr-Si-N or Ti-C-N or Ti-C or C Double layer, stepwise, gradual transition Gradual increase: first layer low argon, second layer gradual increase to higher argon content First layer 0.5 µm to 10 µm second layer 0.1 µm to 2 µm 16 As in example 5, 6, 7 or 15 Multiple layers (more than 2 layers) Alternating layers with higher and lower argon content Individual layers each 0.5 µm to 2 µm 17 As in example 5, 6, 7 or 15 Nanometer layers Alternating layers with higher and lower argon content Individual layers each 5 nm to 50 nm

[0100] The coating according to embodiment 1 can be applied to tools such as for example milling cutters, drills, indexable inserts or the like made of steel, stainless steel or CrMo steel as base material. The coating is a standard layer with low internal stress in the interface region and higher internal stress towards the surface.

[0101] In embodiment 2 the coating is a layer for special applications (in particular a smoothing layer) with low internal stress in the interface region and higher internal stress towards the surface. They can be applied to tools such as for example milling cutters, drills, indexable inserts for machining of aluminium, titanium or non-ferrous metals. Possible applications are applications requiring machining of special materials, where material build-up should be avoided, meaning a smoothing layer is needed.

[0102] According to embodiment 3 the argon content is high at the beginning of deposition and decreases towards the surface. Such a layer can be used for example for thread cutting taps, form taps, drills or punching and stamping tools. Steel, stainless steel or CrMo steel can for example be used as base material. The layer is characterized by a hard base layer with higher internal stress and a soft top layer with good running-in properties and low internal stress. Possible applications of tools with such a layer are in particular tribological applications.

[0103] In embodiment 4 the argon content increases in a gradual manner towards the surface of the coating, so that it is smooth and visually appealing. Such a layer can be used for all types of machining tools and all types of base materials. Possible applications are for example with decorative properties. A colouring top layer can be applied in a separate process.

[0104] The layers according to embodiments 5, 6 and 7 provide on the one hand an improved composition of the layers following each other and on the other hand an improvement of the argon content. This can for example be achieved by equipping the respective HIPIMS magnetron cathodes in the vacuum chamber with targets made of different materials and controlling them separately from each other. By switching off the power supply of a first cathode equipped for example with an Al-Ti target and simultaneously switching on the power supply of a second cathode equipped with a Ti-C target, a change from a first layer to a second layer can be made, for example in embodiment 5. The switching on and off of the correspondingly equipped cathodes can occur abruptly or gradually in the form of a short ramp.

[0105] In embodiment 6 the first cathode is equipped with an Al-Ti target and the second cathode with a Ti-C target; when changing the layer, a switch between the cathodes is made.

[0106] In embodiment 7 the second cathode is equipped with a Ti-C target and the supply of nitrogen as reactive gas is switched off at the beginning of the deposition of the second layer.

[0107] In all three examples 5, 6 and 7, the argon content is abruptly reduced at the beginning of the second layer. The resulting layer can be applied, for example, to the following tools: thread cutting taps, formed taps, drills, punching and stamping tools, for example made of a base material such as steel, stainless steel, or CrMo steel. The application is, for example, tribological applications for which it is advantageous for the resulting layer to have a hard base layer with internal stresses and a softer top layer with good running-in properties and low internal stresses.

[0108] The layer according to example 8 can be used for the same type of tools, base materials and applications as according to examples 5, 6 and 7. In contrast to an abrupt, stepwise reduction of the argon content during the coating duration, according to example 8, the argon content is gradually reduced, i.e. in the form of a ramp.

[0109] The layers according to examples 9, 10 and 11 also provide an improved composition of the layer, which is achieved by cathodes with different target arrangements and a corresponding change in the electrical control. The layers can be applied, for example, to the following tools: end mills, ball nose end mills, drills or indexable inserts, for example made of a base material such as high carbon steel, nickel-based alloys, titanium alloys, or stainless steel. Possible applications of the resulting layer are, in particular, applications requiring mechanical processing, the resulting layer being hard and smooth (property of the second layer with high argon content as functional layer) and having good adhesion (property of the first layer with low argon content acting as an adhesive).

[0110] Examples 12, 13 and 14 can be used for applications such as decorative layers on all types of functional layers or, respectively, layers for better wear detection. Such a layer can thus, for example, be applied to other layers as a top finish in a combined method. All types of mechanical processing tools can be considered as a base made of, for example, steel, cast iron, CrMo steel, or stainless steel. The lower layer acts as a functional layer and the upper layer acts as a decorative color layer with, for example, a golden color, enabling good wear detection.

[0111] Example 15 represents an alternative to examples 12, 13 and 14 for the same applications and bases in the case of a ramped transition of the argon content. In the mentioned variant with a second carbon (C) layer, a grey top layer is produced, enabling simple visual wear detection.

[0112] In the layers of the multi-layer according to example 16 and the nanolayer according to example 17, layers with a high argon content (i.e. high hardness, high internal stresses) alternate with layers with a low argon content. The constant alternation prevents crack formation and enables low internal stresses of the entire system. Such layers can be provided for all types of mechanical processing tools and for base materials such as steel, in particular stainless steel, high carbon steel, CrMo, Ni-based alloys, titanium alloys.

[0113] In summary, the present application can be realized by various coating methods, coating devices, and resulting coated objects, wherein the individual embodiments each provide specific advantages for different applications. The embodiments mentioned in detail here each represent examples and are to be understood as illustrative rather than limiting. Various modifications and alternatives to the embodiments shown are possible. For example, the aforementioned embodiments can be realized with a wide variety of layer materials, i.e. with deviating target arrangements, and in the case of the supply of different reactive gases or also in the case of no supply of reactive gases. It remains advantageous at all times that the resulting coating can be optimized for the respective application by controlled setting of the properties in the different layer regions.

[0114] The present application provides the following technical solutions:

[0115] Scheme 1. A method for applying a layer (64) to an object (60), comprising

[0116] - providing the object (60) in a vacuum chamber (12),

[0117] - supplying a process gas into the vacuum chamber (12),

[0118] - operating at least one cathode (30) and sputtering a target (32) by applying a cathode voltage (V P ) with cathode pulses (50), thereby generating a plasma in the vacuum chamber (12),

[0119] - applying a bias voltage (V B ) to the object (60) during a coating duration (D) such that charge carriers of the plasma are accelerated in the direction of the object (60) and adhere to the surface of the object (60),

[0120] - wherein a time course of the bias voltage (V B ) is varied during the coating duration (D).

[0121] Scheme 2. The method according to scheme 1, wherein

[0122] - the time course of the bias voltage (V B ) comprises bias pulses (52) at least during a part of the coating duration (D), wherein the bias pulses (52) are synchronized with the cathode pulses (50),

[0123] - and the variation of the time course of the bias voltage (V B ) during the coating duration (D) at least comprises

[0124] a) the bias voltage (V B) from a pulsed bias (V B ) with bias pulses (52) to a DC voltage or from a DC voltage to a pulsed bias (V B ) with bias pulses (52),

[0125] and / or

[0126] b) a variation of the duration and / or synchronization of the bias pulses (52) relative to the cathode pulses (50).

[0127] Scheme 3. The method according to scheme 1 or 2, wherein

[0128] - the proportion of the process gas in the layer (64) depends on the time course of the bias (V B ),

[0129] - and wherein the proportion of process gas in the layer (64) is varied by a variation of the time course during the coating duration (D).

[0130] Scheme 4. The method according to one of schemes 1 to 3, wherein

[0131] - the time course of the bias (V B ) comprises bias pulses (52) at least during a first time interval,

[0132] - and wherein the bias (V B ) is a DC voltage at least during a further time interval.

[0133] Scheme 5. The method according to one of the preceding schemes, wherein

[0134] - the time course of the bias (V B ) comprises bias pulses (52) at least during a first time interval (170a, 270a, 370a),

[0135] - wherein the bias pulses (52) are synchronized with the cathode pulses (50),

[0136] - and wherein the bias pulses (52) occur with a delay of a lag time (T D ) relative to the cathode pulses (50).

[0137] Scheme 6. The method according to scheme 5, wherein

[0138] - during the first time interval (170a, 270a, 370a) the bias pulses (52) occur with a delay of a first lag time (T D ) relative to the cathode pulses (50).

[0139] - and the time course of the bias (V B ) comprises a bias pulse (52) which occurs at least during the second time interval (170b, 270b, 370b) in synchronization with the cathode pulse (50) and with a second delay time (T D ) relative to the cathode pulse (50),

[0140] - wherein the first delay time (T D ) is different from the second delay time (T D ).

[0141] Scheme 7. The method according to scheme 6, wherein

[0142] - the duration of the first time interval (170a, 270a, 370a) and / or the second time interval (170b, 270b, 370b) is chosen such that during this time the layer grows between 0.1 pm and 3 pm.

[0143] Scheme 8. The method according to scheme 6 or 7, wherein

[0144] - the first time interval (170a, 270a, 370a) precedes the second time interval (170b, 270b, 370b) within the coating duration (D),

[0145] - and the delay time (T D ) is shorter in the first time interval (170a, 270a, 370a) than in the second time interval (170b, 270b, 370b).

[0146] Scheme 9. The method according to scheme 8, wherein

[0147] - the first time interval (170a, 270a, 370a) is at the beginning of the coating duration (D).

[0148] Scheme 10. The method according to one of schemes 5 to 9, wherein

[0149] - the delay time (T D ) is changed from a first value to a second value stepwise or continuously during a transition time interval.

[0150] Scheme 11. The method according to scheme 10, wherein

[0151] - the duration of the transition time interval is chosen such that during this time the layer grows between 0.5 pm and 20 pm.

[0152] Scheme 12. The method according to one of schemes 5 to 11, wherein

[0153] - the hysteresis time (T D ) has a first value during a first switching sub-interval (670a) and the hysteresis time (T D ) has a second value during a second switching sub-interval (670b)

[0154] - and during the switching time interval, alternating first switching sub-intervals (670a) and second switching sub-intervals (670b) follow each other.

[0155] Scheme 13. The method according to scheme 12, wherein

[0156] - the duration of the first switching sub-interval and / or the second switching sub-interval is / are each selected such that during this time the layer grows 5 nm to 500 nm.

[0157] Scheme 14. The method according to one of the preceding schemes, wherein

[0158] - the cathode (30) is operated by applying the cathode pulses (50) according to the HIPIMS method and the process gas is argon.

[0159] Scheme 15. A device for applying a layer to an object, having

[0160] - a vacuum chamber (12) with a carrier (22) for the object (60), a process gas supply (16), and at least one cathode (30) with a target (32),

[0161] - a pulsed cathode power supply (40) for supplying a cathode voltage (V P ) with cathode pulses (50) to the cathode (30),

[0162] - a controllable bias power supply (42) for applying a bias voltage (V B ) to the object (60)

[0163] - a controller (48) for controlling the bias power supply (60) such that the time course of the bias pulses (52) varies during the coating duration (D).

[0164] Scheme 16. A coated object, comprising

[0165] - a substrate (62),

[0166] - and a layer (64) applied by cathode sputtering to a surface of the substrate (62) having a layer thickness (d),

[0167] - wherein the layer (64) consists of a material comprising at least one element from the group comprising Al, Si, Y and elements from group 4 to 6 of the periodic table according to IUPAC (1988), and at least one element from the group N, O, C, B,

[0168] - and wherein the material of the layer (64) comprises a proportion of a noble gas,

[0169] - wherein the concentration of the noble gas in the layer (64) varies over the layer thickness (d).

Claims

1. A method for applying a layer (64) to an object (60), comprising - placing the object (60) in a vacuum chamber (12), - supplying process gas into the vacuum chamber (12), - By applying a cathode voltage (V P ) to operate at least one cathode (30) and sputter a target (32), thereby generating a plasma in the vacuum chamber (12), - applying a bias voltage (V) to the object (60) during a coating duration (D) B ), so that the charge carriers of the plasma are accelerated toward the object (60) and adhere to the surface of the object (60), - where the bias voltage (V B ), wherein the time course of the coating comprises a bias pulse (52) during at least a portion of the coating duration (D), wherein the bias pulse (52) is synchronized with the cathodic pulse (50), - and wherein the bias voltage (V B ) varies during said coating duration (D); and - where the bias voltage (V B The time course of the cathode pulse (50) includes synchronization with the cathode pulse (50) during a first time interval (170a, 270a, 370a) and delay with respect to the cathode pulse (50) by a first lag time (T D ) occurs a bias pulse (52); and - The bias voltage (V B The time course of the cathode pulse (50) includes synchronization with the cathode pulse (50) during a second time interval (170b, 270b, 370b) and delay with respect to the cathode pulse (50) by a second lag time (T D ) occurs a bias pulse (52); and - within the coating duration (D), the first time interval (170a, 270a, 370a) precedes the second time interval (170b, 270b, 370b); and - The first lag time (T D ) than the second lag time (T D )short.

2. The method according to claim 1, wherein - The proportion of the process gas in the layer (64) depends on the bias voltage (V B ), - and among them, By varying the time course during the coating duration (D), the proportion of process gas in the layer (64) changes.

3. The method according to claim 2, wherein - A first portion of the layer (64) deposited during the first time interval (170a, 270a, 370a) contains a lower proportion of process gas than a second portion of the layer (64) deposited during the second time interval (170b, 270b, 370b).

4. The method according to claim 1, wherein The duration of the first time interval (170a, 270a, 370a) and / or the second time interval (170b, 270b, 370b) is selected such that during this period the layer grows by 0.1 μm to 3 μm.

5. The method according to claim 1, wherein The first time interval (170a, 270a, 370a) is at the beginning of the coating duration (D).

6. The method according to claim 1, wherein - the bias pulse (52) is synchronized with the cathode pulse (50) and delayed relative to the cathode pulse (50) by a lag time (T D )occur, - wherein the lag time (T D ) changes gradually or continuously from a first value to a second value during a transition time interval.

7. The method according to claim 6, wherein The duration of the transition time interval is selected such that during this time the layer grows by 0.5 μm to 20 μm.

8. The method according to claim 4 , wherein - During the first switching subinterval (670a), the lag time (T D ) has a first value, and during the second switching subinterval (670b), the lag time (T D ) has a second value - and during the switching time interval, alternating first switching sub-intervals (670a) and second switching sub-intervals (670b) follow each other.

9. The method according to claim 8, wherein The duration of the first switching subinterval and / or the second switching subinterval is each selected such that during this time the layer grows by 5 nm to 500 nm.

10. The method according to one of the preceding claims, wherein - The cathode (30) is operated by applying the cathode pulse (50) according to the HIPIMS method, and the process gas is argon.

11. A device for applying a layer to an object, having - a vacuum chamber (12) having a carrier (22) for the object (60), a process gas supply (16), and at least one cathode (30) having a target (32), - a pulsed cathode power supply (40) that supplies a cathode voltage (V) with a cathode pulse (50) to the cathode (30) during a coating duration (D) P ), - a controllable bias power supply (42), the controllable bias power supply (42) being used to apply a bias voltage (V B ) - and a controller (48), the controller (48) being configured to control the bias power supply (60) so that the bias voltage (V B ) comprises a bias pulse (52) during at least a portion of said coating duration (D), said bias pulse (52) being synchronized with said cathodic pulse (50), - and wherein the bias voltage (V B ) varies during said coating duration (D); and - where the bias voltage (V B The time course of the cathode pulse (50) includes synchronization with the cathode pulse (50) during a first time interval (170a, 270a, 370a) and delay with respect to the cathode pulse (50) by a first lag time (T D ) occurs a bias pulse (52); and - The bias voltage (V B The time course of the cathode pulse (50) includes synchronization with the cathode pulse (50) during a second time interval (170b, 270b, 370b) and delay with respect to the cathode pulse (50) by a second lag time (T D ) occurs a bias pulse (52); and - within the coating duration (D), the first time interval (170a, 270a, 370a) precedes the second time interval (170b, 270b, 370b); and - The first lag time (T D ) than the second lag time (T D )short.

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