WO2024042076A1

WO2024042076A1 - Coating method for depositing a coating system on a substrate, and a substrate having a coating system

Info

Publication number: WO2024042076A1
Application number: PCT/EP2023/073028
Authority: WO
Inventors: Jörg Vetter; Jürgen Müller
Original assignee: Oerlikon Surface Solutions Ag, Pfäffikon
Priority date: 2022-08-23
Filing date: 2023-08-22
Publication date: 2024-02-29
Also published as: DE102022003082A1

Abstract

The invention relates to a coating method for depositing a coating system (S) on a substrate (1), wherein at least one HiPIMS layer (HS) and one DCMS layer (DS) are deposited on the substrate (1) by means of magnetron sputtering. In the method, a process chamber (3) which can be evacuated, contains a sputtering gas (2, 21, 22), has an anode and a magnetron (4) formed as a cathode, comprising a magnetic field source (41) and a primary target (42) with a coating material (43), is provided. According to the invention, one and the same primary target (42) is used to deposit, in any order and alternately one after the other, the HiPIMS layer (HS) by means of an HiPIMS sputtering method in a HiPIMS mode using a sequence consisting of a plurality of HiPIMS discharge pulses (5) of high power density with a pulse duration (τ1) having at least one atomic layer of the coating material (43), and the DCMS layer (DS) by means of a pulsed and/or non-pulsed DCMS sputtering method in a DCMS mode using a DCMS discharge pulse (6) of low power density with a pulse duration (τ2) in order to form the DCMS layer (DS) from the coating material (43).

Description

Coating process for depositing a layer system on a

Substrate, as well as a substrate with a layer system

The invention relates to a coating method using magnetron sputtering, wherein a layer system is deposited on a substrate alternately in a HIPIMS mode and in a DCMS mode, as well as a substrate with such a layer system according to the preamble of the independent claim of the respective category.

Magnetron sputtering (MS) is a PVD method (Physical Vapor Deposition) that is now firmly established as a standard method in science and technology and is used in particular in different variants to coat substrates with thin layers. For example, for the production of corrosion protection coatings, wear-resistant hard material coatings for tools and machine parts of all kinds, thermoresistive coatings, decorative coatings or optical coatings and is used very successfully for coating substrates in a variety of other applications.

During the sputtering process itself, a vapor of atoms or molecules is generated in an evacuated process chamber from a target comprising a coating material, which are then deposited on the substrate to be coated. The vapor itself is created by knocking out the atoms or molecules from the target using an ionized working gas (sputtering gas), which is usually an inert gas, often a noble gas such as argon (Ar) or krypton (Kr). The ions of the working gas are released by an electrical discharge, which leads to the generation of electrons, which in turn form the gas ionize, generated. During MS, a magnetic field is generated in the vicinity of the target, which forces the generated electrons into a kind of electron cloud, which leads to a concentration of the electrons in front of the surface of the target, which enables increased ionization of the sputtering gas. The target is at a lower electrical potential than the area in which the electron cloud is positioned. This accelerates the positive ions towards the target and knocks atoms or molecules of the coating material out of the target. The released atoms or molecules ultimately deposit on all surfaces within the process chamber and thus also on the surface of the substrate to be coated.

Compared to other sputtering processes that work without the support of a magnetic field, MS achieves relatively high ionization efficiencies due to the magnetic confinement of the electron cloud. The result of this is that only a relatively low electrical power is required while at the same time high sputtering rates. Through a suitable choice of the magnetic field geometry, the loss of electrons perpendicular to the magnetic field lines can also be greatly reduced, thereby minimizing the impact of these on the substrate and thus significantly reducing the heating of the substrate, in particular of the coating growing on the substrate.

MS enables the use of a wide variety of available materials. In addition to metals and their alloys, less conductive materials as well as brittle materials such as Si, B, Ti, TiB2 SiC, B4C, M0S2, WS2 and many other materials can also be sputtered.

The use of MS as a coating process is also ideal for reactive sputtering using reactive process gases, such as C2H2, NH3, Ar, N2, O2 and their mixtures, as well as a variety of other reactive process gases. For reactive deposition of, for example The corresponding reactive gas is added to nitride, carbide or oxide layers and their mixtures. During reactive sputtering, the sputtered atoms or molecules react with the reactive process gases, with the reaction products ultimately forming the coating on the substrate.

To date, a large number of variants of magnetron sputtering (MS) have been developed.

With classic DC magnetron sputtering (DCMS), either DC voltages are used as sputtering voltages on the target (unpulsed DCMS) or with pulsed DCMS, the DC voltage is applied to the target in a sequence of separated individual pulses. Typically, time-integrated power densities of up to 20W/cm ² are achieved on the target, with typical current densities on the target usually being below 0.1A/cm ² .

Compared to other sputtering processes, DCMS enables high layer rates when building up the coatings on the substrate. Since a low substrate temperature can be guaranteed during the coating process, it is also possible to coat sensitive materials.

Advantageous properties of coatings produced by DCMS include high adhesion of the coatings to the substrate as well as low porosity and lower defect densities in the layers.

In addition, magnetically assisted DCMS causes little radiation damage to the substrate being coated.

A major disadvantage of MS in general and of DCMS in particular is the low utilization of the target, which is well known to those skilled in the art, and the associated effect that the deposited layers often have uneven thicknesses. The reason for this is that due to the low energy (temperature) that the electrons have, the ionization of the sputtering gas takes place in a very localized manner and the location of the ionization regions is thus imaged on the target surface, which leads to uneven erosion or wear of the target (formation of sputtering trenches), which in turn means that only a limited part of the target can be used until it has eroded through.

There are limits to increasing the amount of ionized gas with DOMS. Of course, the amount of ionized sputtering gas can be increased relatively easily by increasing the applied sputtering voltage, but this significantly increases the probability of arcing and leads to the negative layer properties known to those skilled in the art. At the same time, an increased sputtering voltage is limited because thermal overheating of the target limits the power introduced.

In addition, the layers produced by DOMS are often characterized by pronounced columnar growth due to the relatively low ionization of the sputtered material, which unfortunately often leads to a disadvantage in the functionality of the layers in many applications.

Therefore, classic DC magnetron sputtering (DOMS) has been constantly developed and improved over the past years and decades. Significant progress has been achieved by operating the magnetron in pulsed mode with high currents or current densities, which leads to an improved layer structure in the form of denser layers, in particular due to improved ionization of the sputtered material. This means, for example, that columnar growth can be significantly suppressed or even prevented entirely.

Such methods of magnetron sputtering in pulsed mode with high currents or current densities are well known to those skilled in the art under the name “High Power Impulse Magnetron Sputtering” or HiPIMS for short. The Current densities at the target in HiPIMS typically significantly exceed those of classic DCMS, ie they are often well above 0.1 A/cm ² and up to a few A/cm ² , so that power densities range from a few 100W/cm ² up to MW/cm ² can be in contact with the target for a short time. Compared to conventional DCMS, HiPIMS is characterized by a higher plasma density and therefore a significantly higher ionization capacity of the working gas and the reactive gas, especially the proportion of ionized sputtered target atoms.

To illustrate the enormous improvement in ionization rates when using a HiPIMS sputtering process compared to a DCMS sputtering process, reference is made to the following numerical example.

Typically, in a HiPIMS or DCMS coating process, the process pressure in the process chamber is in a pressure range of approximately 10' ⁴ Torr to 10 ^-2 Torr (approx. 0.013 Pa to 1.3 Pa). In practice, with a classic DCMS sputtering process, a maximum cathode current density is in the range of Jmax < 0.1 A/cm ² , with the discharge voltages in the range of approximately 0.3kV to 0.6kV. By appropriately selecting cathode current density and discharge voltage, corresponding cathode power densities are usually selected in the range of less than 0.1 kW/cm ² . At a process pressure of, for example, 1 Pa in the process chamber, the particle number n is approximately 1 O ²⁰ atoms per m ³

From this number of atoms, approximately 10 ¹⁶ to a maximum of 10 ¹⁸ of all gas neutral particles in the mixture of process gas and target material, i.e. only between 0.01% and a maximum of up to 1% of all neutral particles, can be ionized in a DCMS sputtering process. This means that an ionization fraction of a maximum of approx. 1% is achieved. Of these, only about 1% to about 3% consist of ionized target atoms. In a HiPIMS sputtering process, on the other hand, a much higher maximum cathode current density in the range of Jmax <10 A/cm ² is chosen, with the discharge voltages in the range of approximately 0.5kV to 1.5kV. Through a suitable selection of cathode current density and discharge voltage, corresponding cathode power densities are usually set in a range from approximately 1 kW/cm ² to approximately 3 kW/cm ² in a HiPIMS process. As already mentioned above, with a process pressure of, for example, 1 Pa in the process chamber, the particle number n is approx. 1O ²⁰ atoms per m ³ From this number of atoms, approx. 3'10 ¹⁹ up to approx. 9' can be formed in a HiPIMS sputtering process. 10 ¹⁹ of all gas neutral particles in the mixture of process gas and target material, i.e. an enormous proportion of between approx. 30% and 90% of all neutral particles, are ionized. This means that an enormous ionization fraction of between approx. 30% and 90% is achieved. Of these, the ionized target atoms can form a volume fraction of up to 90%.

All sputtering techniques have an inherent performance limit, which is determined by the coolability of the target and the target material itself. If the temperature on the target surface cannot be dissipated quickly enough, the target material melts. With conventional DCMS, the upper limit of the power densities on the target is usually in the range of at most 50W/cm ² . This maximum load limit in continuous DCMS operation is often only a maximum of 20W/cm ² . In order to further increase the power without overheating the target, the discharge must be pulsed. The increasing energy input and the associated temperature development on the target surface can be compensated for by reducing the duty cycle. For this purpose, the sputtering frequencies and pulse lengths are varied in the high-performance range.

The high degree of ionization of the sputtered target atoms when using a HiPIMS process offers improved control of layer growth and layer structure. By applying an electrical substrate bias voltage (Bias voltage) the energy of the incoming ions can also be controlled and the latter can be controlled specifically. Targeted ion bombardment using sputtering gas ions (e.g. Ar) and in particular the ions of the sputtered target material can have a significant influence on the structure and layer properties, as well as crystal orientation, grain size, density and mechanical layer tension. The high degree of ionization enables the layer quality to be improved through higher density and hardness, improved layer adhesion and lower roughness.

Key features of the HiPIMS are peak currents and peak power densities that are up to several orders of magnitude higher than their average power density.

The advantages of coatings produced using HiPIMS are, in particular, a denser layer morphology. With various layer systems, such as AITiN layers, this can lead to higher hardness but also to a lower modulus of elasticity.

For example, while comparable TiAIN or AITiN layers produced using DCMS have a hardness of typically in the range of up to 27 GPa and an elastic modulus of up to 400 GPa, the hardness of such coatings produced using HiPIMS can easily reach up to 35 GPa E-modulus of up to 500 GPa. The ratio of hardness and modulus of elasticity is a measure of the toughness properties of the layer. A high level of hardness with a relatively low modulus of elasticity is beneficial for many applications. Using the method according to the invention, optimization is possible by combining both types of layers.

Another very important advantage of the HiPIMS layers is the extremely high thermal stability, which results, among other things, from the denser layer structure.

In addition, the use of HiPIMS can improve the layer adhesion

Compared to layers produced using the DCMS process so that HiPIMS layers are particularly advantageous for use, for example, in the coating of cutting tools, which can therefore be manufactured with significantly increased cutting parameters and are characterized by much lower tool wear during operation.

However, the expert is also confronted with some disadvantages of the HiPIMS process, which are briefly outlined below, although the following list is not intended to be exhaustive.

In some coating processes, it is not uncommon for increased internal stresses (internal stresses) to be observed in HiPIMS coatings, which can lead to mechanical defects such as cracks, bulges or the layer flaking off.

The deposition rate and thus the speed of layer growth (coating rate) is also significantly reduced in HiPIMS processes compared to DCMS processes, both in reactive and non-reactive processes. The deposition rates and thus the coating rates with HiPIMS can be reduced by up to 70% compared to DCMS.

A main cause of the lower coating rates of the HiPIMS discharge compared to the DCMS discharge with the same input energy is the backflow effect of the ions. This is essentially caused by the fact that a proportion of the positively charged ions of the sputtered target material are drawn back to the day, which is negatively biased, due to the spatial plasma potential distribution during the high-voltage pulse. This results in “self-sputtering” of the target. This is also referred to as “re-deposition”. Unfortunately, this negative effect is precisely a characteristic of the HiPIMS sputtering process. Finally, the problem of “arcing”, which is well known to those skilled in the art, is significantly higher in HiPIMS processes than in DCMS processes. The expert understands arcing to mean unwanted discharges that can be observed, for example, on sputtering targets. These discharges are local, time-limited cathodic vacuum arc discharges. Arcing leads in particular to uneven coating, particularly through the formation of undesirable particles that have a negative impact on the coatings.

Last but not least, the energy consumption per slice volume with HiPIMS is significantly higher than when using a DCMS process.

In addition to the use of pure HiPIMS methods or the use of pure DCMS methods, so-called hybrid methods are also known in the prior art, which use one or more identical or different magnetrons or sputtering sources in different variants of HiPIMS methods and DCMS -Use processes to form coatings on a substrate simultaneously in the same process step.

The idea is to combine the advantages of HiPIMS and DCMS coating processes. A current overview of such coating techniques can be found, for example, at V.O. Oskirko et al. In Vacuum 181 (2020) 109670.

By using such hybrid coating processes, some of the disadvantages described above can be at least partially reduced. However, due to the nature of the process, such hybrid processes have, among other things, other significant disadvantages or impose restrictions on the coating processes, which in turn completely or partially nullify the advantages of such processes.

For example, in these hybrid processes in which HiPMS and DCMS processes are used simultaneously, i.e. mixed, the gas pressure in the process chamber or the bias voltage on the target can either only be used for the HiPIMS portion of the hybrid process or only for the DCMS portion of the hybrid process can be optimized. Or you have to look for compromises for these or other process parameters, which then do not lead to sufficiently optimal coating results.

Especially when it comes to reactive coating processes using reactive process gases, such hybrid processes lead to massive, unavoidable restrictions in process design. In these hybrid processes, the reactive gases used, their mixtures, partial pressures (flows), etc. cannot naturally be optimally adapted to the HiPIMS process and the DCMS process at the same time, since both processes are used at the same time and ultimately changes in these process parameters of the gas flows can also only be carried out very sluggishly, so that in principle, with the known hybrid processes, a simultaneous optimal choice of parameters for the HiPIMS process and the DCMS process is excluded, both with regard to the layer properties, the layer thickness of the individual layers depending on the load and rotation, as well also the separation rates.

The person skilled in the art knows that the coating rates BR in both the HiPIMS and the DCMS process depend sensitively on the one hand on the magnetic field strength MFS of the magnetic field in front of the target and on the pulse frequencies of the HiPIMS or DCMS pulse sequences, as shown for example in FIG. 4 ( J W Bradley et al 2015 J. Phys. D Appl.

Phys. 48 215202) should be remembered again. The essential point is that the dependence of the coating rate BR on the magnetic field strength MFS of the magnetic field in HiPIMS processes and DCMS processes is exactly the opposite, as can be clearly seen from FIG. 4.

While in DCMS processes the coating rate BR increases with

Magnetic field strength MFS of the magnetic field increases, increases in HiPIMS processes the coating rate BR decreases with increasing magnetic field strength MFS of the magnetic field. Note that in Fig. 4 the magnetic field strength MFS of the magnetic field increases to the left.

With the known hybrid methods, this of course means that the magnetic field strength MFS of the magnetic field can either only be optimally adapted to the HiPMS process or only to the DCMS process, or that a compromise has to be made with regard to the magnetic field strength MFS of the magnetic field, so that the magnetic field strength MFS of the magnetic field cannot be selected either optimally for the HiPIMS process or optimally for the DCMS process.

The object of the invention is therefore to provide an improved coating process for producing a multilayer system by means of magnetron sputtering and, as a result, a substrate with an improved layer system, whereby all the advantages of the HiPIMS and those of the DCMS process can be optimally realized at the same time, without the disadvantages of the known hybrid processes.

The objects of the invention that solve these tasks are characterized by the features of the respective independent claims. The dependent claims relate to particularly advantageous embodiments of the invention.

The invention therefore relates to a coating method for depositing a layer system on a substrate, wherein at least one HiPIMS layer and one DCMS layer are deposited on the substrate by means of magnetron sputtering. An evacuable process chamber containing a sputtering gas, with an anode and a magnetron designed as a cathode, comprising a magnetic field source and a primary target with a coating material, is provided. According to the invention, one and the same primary target is used in any order and one after the other the HiPIMS layer is alternately deposited from the coating material by a HiPIMS sputtering process in a HiPIMS mode using a sequence consisting of a plurality of HiPIMS discharge pulses of high power density with a pulse duration of at least one atomic layer, and the DCMS layer is deposited by a pulsed and/or or unpulsed DCMS sputtering process in a DCMS mode using a DCMS discharge pulse of low power density with pulse duration to form the DCMS layer from the coating material.

The present invention has made it possible for the first time to successfully combine the HiPIMS sputtering process and the DCMS sputtering process in a single coating process in such a way that, for the first time, essentially all of the advantages of the DCMS sputtering process and essentially all of the advantages of the HiPIMS sputtering process for the formation of layer systems on a substrate can be exploited at the same time without having to compromise on the coating parameters in favor or disadvantage of the HiPIMS sputtering process or the DCMS sputtering process.

A coating process according to the invention therefore has practically all of the advantages of DCMS sputtering, such as high coating rates, ensuring a low substrate temperature for coating sensitive materials, high adhesive strength of the coatings on the substrate, low porosity and lower defect densities in the layers, while at the same time being low Radiation damage to the substrate to be coated due to the magnetic field of the magnetron, as well as lower energy consumption.

At the same time, a coating process according to the invention also shows all the advantages of the HiPIMS sputtering processes known per se. Such as a high degree of ionization of the sputtering gases and the sputtered target atoms, which results in improved control of the layer growth and the layer structure guaranteed. Targeted ion bombardment using sputtering gas ions (e.g. Ar) and in particular the ions of the sputtered target material can have a significantly positive influence on the structure and layer properties, as well as crystal orientation, grain size, density and mechanical layer tension. The high degree of ionization in HiPIMS sputtering enables a significant improvement in layer quality through higher density and hardness, even further improved layer adhesion, and lower roughness.

Advantages of coatings produced using HiPIMS include, in particular, denser layer morphology and less columnar layer growth. This can lead to higher hardness with different layer systems, such as AITiN layers. Another very important advantage of the HiPIMS layers is the extremely high thermal stability, which results, among other things, from the denser layer structure.

Not only can all of these advantages of the HiPIMS sputtering processes and DCMS sputtering processes be successfully combined for the first time by the coating process according to the invention. The well-known disadvantages of the HiPIMS sputtering process and those of the DCMS sputtering process can at least be significantly reduced or avoided entirely. This is particularly true with regard to the hybrid sputtering processes known from the prior art, which, as already described, have attempted to combine the advantages of HiPIMS sputtering and DCMS sputtering with rather moderate success and at the expense of significant disadvantages. by carrying out a HiPIMS sputtering process and a DCMS sputtering process simultaneously or superimposed.

In pure HiPIMS layer systems, it is not uncommon for increased internal stresses (internal stresses) to be observed, which can lead to mechanical defects such as cracks, bulges or the layer flaking off. This danger is eliminated by the deposition according to the invention Pure HiPIMS and DCMS layers deposited alternately directly on top of each other are significantly reduced or almost completely avoided.

The problem of the relatively low deposition rate and thus the speed of layer growth (coating rate) is also significantly reduced with pure HiPIMS processes in relation to the entire layer system. This applies to both reactive and non-reactive processes. Thus, the deposition rates in a method according to the invention can be easily adjusted according to the invention, depending on the process control and the ratio of the layer thicknesses of HiPIMS partial layers to DCMS partial layers of a layer system according to the invention, and thus the coating rates compared to coatings that are only deposited using a HiPIMS sputtering method, for example e.g. 15% or 50% and up to 90% or more.

As already mentioned, a main cause of the lower coating rates of the pure HiPIMS discharge compared to the DCMS discharge with the same input energy is the backflow effect of the ions. This is essentially caused by the fact that a proportion of the positively charged ions of the sputtered target material are drawn back to the target, which is negatively biased, due to the spatial plasma potential distribution during the high-voltage pulse. This results in “self-sputtering” of the target. This is also referred to as “re-deposition”. This negative effect is known to be an inherent characteristic of the HiPIMS sputtering process and of course cannot be avoided per se even in a corresponding sub-step of a HiPIMS sputtering process as part of a coating process according to the invention.

However, in a coating process according to the invention, this essential disadvantage of the HiPIMS sputtering process is at least partially exploited positively. As already stated, a major disadvantage of magnetron sputtering in general and of pulsed or non-pulsed DCMS in particular is the low utilization of the target and the associated effect that the deposited layers often have uneven thicknesses. The reason for this is that the ionization of the sputtering gas takes place in a very localized manner and the location of the ionization regions is thus imaged on the target surface, which leads to uneven erosion or wear of the target (formation of sputtering trenches), which in turn leads to only one A limited part of the target can be used until it has eroded through.

Here, the above-described, inherently negative re-deposition effect of the HiPIMS sputtering process suddenly has a surprisingly positive effect in a H iPIMS step following a DCMS step due to the present invention. The re-deposition effect in the HiPIMS process step caused by the "backflow" of the sputtered target ions leads to target ions that have already been sputtered returning to the target, re-depositing on the target surface and thus the "damaged" by the previously carried out DCMS sputtering. At least partially restore the surface of the target, so to speak at least partially heal it, by at least partially repairing the erosion damage caused by DCMS sputtering by re-depositing target ions that have fallen back onto the surface of the target. As a result, with a coating process according to the invention, the targets can not only be used for much longer than with a pure DCMS sputtering process, but the DCMS partial layers become more uniform when using a coating process according to the invention, i.e. have, among other things, a significantly more uniform thickness than when using a known one pure DCMS sputtering process. Of course, this not only has an isolated effect on the DCMS layers of a layer system according to the invention, but also improves the properties of the layer system according to the invention overall, e.g. in terms of the adhesion of the partial layers, resistance to chipping, hardness, temperature resistance, etc.

With a coating method according to the invention, the known and above-described problem of “arcing” in HiPIMS processes is also significantly reduced overall in relation to the formation of the layer system. Simply because the HiPIMS process steps are only used during part of the entire coating process, i.e. not over the entire coating period.

Especially in comparison to the known hybrid processes, in which at least some HiPIMS pulses and DCMS pulses are applied to the target at the same time, which can lead to arcing due to the mixed-in HiPIMS discharge pulses even during the arcing itself unproblematic DCMS coating phases can be induced, the coating process according to the invention shows significantly better properties and leads to significantly improved properties of the layer systems according to the invention.

It should be pointed out very expressly that the coating process according to the invention should under no circumstances be confused with the hybrid coating processes already discussed above. The coating process of the present invention has very significant advantages, particularly in comparison to the known hybrid processes from the prior art, in which HiPIMS sputtering processes and DCMS sputtering processes are carried out simultaneously or overlapping in time, which are fundamentally not the case with the known hybrid processes can be achieved. In addition, such known hybrid processes have significant process-related disadvantages or impose restrictions on the coating processes that can essentially be completely avoided by the present invention. For example, as already described, in the known hybrid processes in which HiPMS and DCMS methods are used simultaneously, i.e. mixed, the gas pressure in the process chamber or the bias voltage on the target or the magnetic field strength on the target can either only be used for the HiPIMS portion of the hybrid process or only for the DCMS portion of the hybrid process can be optimized. Or you have to look for compromises for these or other process parameters, which then do not lead to sufficiently optimal coating results.

With a coating method according to the invention, however, it is easily possible to optimize process parameters such as the gas pressure in the process chamber and/or the bias voltage on the target and/or the magnetic field strength on the target separately for both the HiPIMS process step and the DCMS process step to choose, although according to the invention the HiPIMS layer and the DCMS layer are produced with one and the same primary target, because in a method according to the invention, in contrast to the known hydride methods, the HiPIMS sputtering process and the DCMS sputtering process are decoupled from one another in time, and be carried out one after the other alternately.

This is a significant advantage of the method according to the invention, especially with regard to reactive coating processes using reactive process gases, compared to the known hybrid processes in which HiPIMS processes and DCMS processes are carried out at the same time or superimposed. In contrast to the known hybrid processes, in a coating process according to the invention, the reactive gases used, their mixtures, partial pressures, flows, etc. can each be optimally adapted to the HiPIMS process and to the DCMS process separately, even if the change in these process parameters is rather slow go, since according to the invention the two different sputtering processes are not used simultaneously but rather in a time-decoupled manner one after the other. Another significant advantage of a method according to the invention compared to the known hybrid methods results from the fact that, as already mentioned, the coating rates in both the HiPIMS and the DCMS process depend sensitively on the one hand on the magnetic field strength of the magnetic field in front of the target. The essential point is that the dependence of the coating rate on the magnetic field strength of the magnetic field in HiPIMS processes and DCMS processes is exactly the opposite, as has already been impressively shown in FIG. 4.

While in DCMS processes the coating rate increases with increasing magnetic field strength MFS of the magnetic field, in HiPIMS processes the coating rate decreases with increasing magnetic field strength MFS of the magnetic field.

In contrast to the known hybrid methods, when using a method according to the invention, the magnetic field strength of the magnetic field in front of the magnetron can easily be optimally adapted to both the HiPIMS process and the DCMS process separately, without having to make a compromise with regard to the magnetic field strength of the magnetic field , as with the well-known hybrid processes. Typical magnetic field strengths are, for example, in the range from approx. 50Gauss to approx. WOOGauss. In practice, magnetic field strengths in the range of approximately 50Gauss to 600Gauss are advantageously selected for the HiPIMS process, while typical magnetic field strengths for the DCMS process are often in the range of approximately 300Gauss to WOOGauss.

Of course, because the two different sputtering methods HiPIMS and DCMS are not used simultaneously according to the invention, but are decoupled from one another in time.

Last but not least, of course, is the consumption of electrical energy per deposited layer volume in a device according to the invention Coating process significantly reduced, at least in comparison to a known pure HiPIMS sputtering process.

Essential exemplary embodiments and process parameters are reported below in general and schematic form, which have proven to be advantageous for carrying out coating processes according to the invention and for producing corresponding substrates.

In the HiPIMS mode in a method according to the invention, the maximum power density of the HiPIMS discharge pulse on the primary target is preferably in a range of 0.05kW/cm ² and 10kW/cm ² , preferably 0.1 kW/cm ² and 5kW/cm ² , in particular from 0.2kW/cm ² to 3kW/cm ² , particularly preferably at approximately 0.4kW/cm ² or 2kW/cm ² , whereby in HiPIMS mode in the sequence of HiPIMS discharge pulses, the pulse duration of the HiPIMS discharge pulse is between 5ps and 20ms, preferably between 20ps and 10ms, in particular at approximately 50ps to 5ms and / or in HiPIMS mode a HiPIMS dead time in the sequence of HiPIMS discharge pulses between two successive HiPIMS discharge pulses between 100ps and 500ms, preferably between 250ps and 250ms, in particular between approximately 500ps and 150ms, and / or wherein a HiPIMS duty cycle of a sequence of HiPIMS discharge pulse and HiPIMS death time between 0.5% and 20%, preferably between 1% and 10%, in particular is preferably chosen between approximately 2% to 6% of the duration of the sequence of HiPIMS discharge pulse and HiPIMS death time.

In a special embodiment of the present invention, it is possible that in a sequence of HiPIMS discharge pulses and HiPIMS death time, the pulse duration of the HiPIMS discharge pulse and / or the duration of the HiPIMS death time and / or the HiPIMS duty cycle during the deposition of the Shift system is changed according to a predeterminable scheme. This procedure can be used advantageously, for example, to optimize the layer properties or sub-layers with varying ones To create layer properties such as adhesive strength, hardness, internal stresses, thermal resistance, elastic modulus and other varying or different properties. The gradient layers according to the invention mentioned later can also be generated in this way.

In the DCMS mode, however, the power density of the DCMS discharge pulse on the primary target is preferably in a range of 1W/cm ² and 50W/cm ² , preferably between 2W/cm ² and 30W/cm ² , particularly preferably approximately 5W /cm ² to 25W/cm ² is selected, and / or in the pulsed and / or unpulsed DCMS mode, the pulse duration of the DCMS discharge pulse is advantageously but not necessary between 1 ps and 10ms, preferably between 5ps and 500ps, in particular at approx. 20ps or 200ps is selected, whereby in pulsed DCMS mode a DCMS death time in a sequence of DCMS discharge pulses between two successive DCMS discharge pulses in practice is often between 0.5ps and 10ms, preferably between 2ps and 300ps, in particular at approx. 5ps to 100ps is selected, and / or wherein a DCMS duty cycle of a sequence of DCMS discharge pulse and DCMS death time is between 30% and 99%, preferably between 50% and 97%, particularly preferably at approximately 75% or 95% of Duration of the sequence from DCMS discharge pulse and DCMS death time is selected.

In a further special exemplary embodiment of the invention, in a sequence of DCMS discharge pulses and DCMS death time, the pulse duration of the DCMS discharge pulse and / or the duration of the HiPIMS death time and / or the HiPIMS duty cycle during the deposition of the layer system can be after a predetermined scheme can be changed. Such manipulation of the parameters of the DCMS pulse sequences can also be used advantageously to optimize the layer properties of a layer system according to the invention or to create partial layers with varying layer properties such as adhesive strength, hardness, internal stresses, thermal To create resistance, elastic modulus and other varying or different properties. The gradient layers according to the invention mentioned later can also be generated in this way.

In practice, the HiPIMS discharge pulse of high power density and/or DCMS discharge pulse of low power density is a rectangular and/or a triangular and/or a needle-shaped discharge pulse, in particular a bipolar discharge pulse or a bipolar sequence of discharge pulses, as are known per se are and e.g. in Figs. 3a to 3f. are shown schematically.

As already indicated, in a coating method according to the invention, the HiPIMS layer can be deposited in the HiPIMS mode and/or the DCMS layer in the DCMS mode using a reactive and/or a non-reactive sputtering process, the HiPIMS layer being deposited in the HiPIMS -Mode using an HP process gas and the DCMS layer is deposited in the DCMS mode using a DC process gas different from the HP process gas, and / or wherein the HP process gas and / or the DC process gas is preferably a mixture of a number of different reactive gases are used.

In a particularly preferred embodiment of a reactive sputtering method according to the invention, during the deposition of the HiPIMS layer in the HiPIMS mode, a composition of the HP process gas and / or during the deposition of the DCMS layer in the DCMS mode, a composition of the DC process gas according to one predetermined scheme can be varied, for example, but not only, to form a gradient layer with regard to its chemical composition or to optimize the layer properties or partial layers with varying layer properties such as adhesion, hardness, internal stresses, thermal To create resistance, elastic modulus and other varying or different properties.

For the same or other reasons, which depend on the desired properties of the layer system to be created, a partial pressure of the HP process gas can be used during the deposition of the HiPIMS layer in the HiPIMS mode and / or during the deposition of the DCMS layer in the DCMS mode a partial pressure of the DC process gas can be varied.

Likewise, for the same or other reasons that depend on the desired properties of the layer system to be produced, during the deposition of the HiPIMS layer in HiPIMS mode, an HP bias voltage of the substrate can be different from a DC bias voltage during deposition of the DCMS layer can be selected in DCMS mode and / or during the deposition of the HiPIMS layer in HiPIMS mode the HP bias voltage can be varied and / or during the deposition of the DCMS layer in DCMS mode the DC can also be varied Bias voltage of the substrate can be advantageously varied.

Particularly advantageously, as already described above, a magnetic field strength of the magnetic field source during the pulsed and / or unpulsed DCMS sputtering process can be selected to be different from a magnetic field strength of the magnetic field source during the HiPIMS sputtering process.

This can be done, for example, by means of a mechanical adjustment device, for example by means of a stepper motor or other mechanical adjustment units that are known to those skilled in the art, which determine the position and/or orientation of the magnetic field source in relation to the magnetron or in relation to the primary Target can be changed or adjusted so that the magnetic field strength at the location or in the surroundings of the magnetron or the primary target can be variably adjusted to a predetermined value. Of course, it is also possible that, as an alternative or in addition to the mechanical adjustment device described above, the magnetic field strength can be controlled in a manner known per se by varying a current via an electromagnetic coil, which can be provided in the vicinity of the magnetron and / or the primary target the electromagnetic coil is changed or adjusted so that the magnetic field strength at the location or in the surroundings of the magnetron or the primary target can be variably adjusted to a predetermined value.

In principle, in addition to the previously mentioned options, other measures known to those skilled in the art can also be taken to change the magnetic field strength at the location of the magnetron or at the location of the primary target during a coating step. For example, to produce a gradient layer and/or to optimally adjust the magnetic field strength on the magnetron and/or on the primary target for carrying out the HiPIMS sputtering process and/or the DCMS sputtering process.

And of course it is also possible for the strength of a magnetic field on the additional magnetron to also be adjusted as described above, even with an additional magnetron in the coating chamber, if present.

As has already been mentioned several times, in special exemplary embodiments of the present invention, the HiPIMS layer and/or the DCMS layer can be deposited as a gradient layer as described, which can be particularly advantageous depending on the application, as the person skilled in the art knows.

The gradient layer can be formed, among other things, by varying the chemical composition of the HP process gas and/or by varying the chemical composition of the DC process gas or using other measures known per se. Since, in addition to the described sequences of HiPIMS and DCMS layers deposited directly on top of one another according to the invention, other types of partial layers can also be provided in layer systems according to the invention that are complex in terms of layer structure and layer structure, a plurality of identical or different magnetrons can also be included in a process chamber for carrying out the invention Primary target, in particular comprising different coating materials, can be provided, and/or at least one further magnetron with a target with a further coating material can be provided in the process chamber.

A process time for producing the HiPIMS layer and/or the DCMS layer produced in an unpulsed and/or pulsed DCMS sputtering process is, for example, in the range from 0.5s to 10,000s, preferably 1s to 5000s, in particular from approximately 5s to 2500s , where a ratio of the proportions of the sum of the layer thicknesses of the HiPIMS layers divided by the sum of the layer thicknesses of the DCMS layers produced in an unpulsed and / or pulsed DCMS sputtering process within the overall layer z. Example in a range from 0.02 to 50, preferably in a range from 0.05 to 25, in particular in a range from 0.1 to 9.

A thickness of the individual layer, which can be varied in layer thickness, in a layer system consisting of the HiPIMS layers and the DCMS layers produced in an unpulsed and / or pulsed DCMS sputtering process can be in a range from 1 nm to 5000 nm, preferably in a range from 2 nm to 500nm, in particular in a range from 5nm to 250nm.

Two specific exemplary embodiments of layer systems will be described below, one layer system being deposited using a non-reactive sputtering process according to the invention and another layer system being deposited using a reactive sputtering process according to the invention. In these two special exemplary embodiments, layer systems according to the invention made of TiB or AITiN were used Use of a rectangular primary target with a length of approx.

70cm and a width of approx. 7.5cm.

Embodiment 1 (non-reactive process)

A non-reactive coating process according to the invention was used as an example for the deposition of TiB2 hard material layers, which is explained below as an example for all other non-reactive coating processes, including for metals and their alloys, silicon and others.

In all coating processes according to the invention carried out, a target power of approximately 4.5 kW was selected for the bonded TiB2 target mounted on the magnetron. The flow of argon used as sputtering gas was 120 sccm. A negative bias voltage of 125V was applied to the substrate holder. The coating time was 2 hours. In the method according to the invention, a modulated layer consisting of a HiPIMS single layer with a deposition time of 4 min plus a pulsed DCMS single layer with a deposition time of 2 min was deposited within 2 hours. The result was an alternating layer structure, as shown in general and as an example in Fig. 2c, whereby, depending on the process, either the HiPIMS layer or the DCMS layer was of course applied directly to the substrate. The most important deposition parameters and the results are summarized in Table 1 below.

The pulsed DCMS process, which does not belong to the HiPIMS discharges, is characterized by typical values for this process. The maximum current density of 0.017 mA/cm ² at the target, which is constant throughout the entire pulse, corresponds to a power of 8.5 W/cm ² The HiPIMS process is characterized by typical peak values. The maximum current density of 0.48 A/cm ² is 30 times greater than in the pulsed DCMS process, the peak power density is approx. 350W/cm ² . The absolute peak power is 189kW. The layer sequence of pulsed DCMS and HiPIMS resulting from the layer rate of 0.67 m/h results in a thickness of the double layer of approx. 66nm.

The division within the double layer results from the coating rates in the pure HiPIMS process and in the pure pulsed DCMS process. A HiPIMS single layer has approx. 36nm and a pulsed DCMS single layer has approx. 30nm.

Table 1: Process parameters for deposition of a TiB2 layer system.

The coating rates were determined using a method well known to those skilled in the art using dome grinding. The hardness was measured with a load of 30mN using a Berkovich diamond and the internal stresses were determined using a bending method in a manner known per se.

The method according to the invention shows a significant increase in the coating rate compared to the pure HiPIMS method in the direction of the rate of the pulsed DCMS method. A reduction in the internal stress state compared to the HiPIMS process could also be achieved without a significant loss of hardness.

Embodiment 2 (reactive process)

A reactive coating process for the deposition of AITiN hard material layers was implemented, which is representative of all other possible reactive processes with different reactive gases. For all coatings, a target power of 10 kW was selected for the targets with the composition 55 at% Al and 45 at%. The flow of argon used as sputtering gas was 120 sccm. A stepped preload of 40V, 80V and 120V were applied to the substrate holder for one third of the total coating time. The coating time for the HiPIMS was

process and the DCMS process 2h. In the method according to the invention, a modulated layer consisting of a HiPIMS single layer was used

Deposition time of 4 minutes plus a pulsed DCMS single layer

Deposition time of 2 m in deposited with 13 layers. The most important

Deposition parameters and the results are shown in Table 2.

Table 2: Process parameters for deposition of an AITiN layer system.

As in exemplary embodiment 1, the coating rates were determined using a method well known to those skilled in the art using dome grinding. The hardness was measured with a load of 30mN using a Berkovich diamond and the internal stresses were determined using a bending method in a manner known per se.

The pulsed DCMS process, which does not belong to the HiPIMS discharges, is characterized by typical values for this process. The maximum current density of 0.034 mA/cm ² , which is constant throughout the entire pulse (power 10kW), corresponds to a power density of 19W/cm ² . The HiPIMS process is characterized by typical peak values in the pulse. The maximum current density of 1.43A/cm ² is 42 times greater than in the pulsed DCMS process, the peak power density is approx. 1180W/cm ² . The absolute peak power is 618kW. The single layer thicknesses within a HiPIMS-DCMS double layer were 135nm for the HiPIMS single layer and 145nm for the DCMS single layer. This made it possible to show that due to the lower nitrogen flow in the process according to the invention of 45 sccm, a thicker layer could be deposited compared to the pure HiPIMS layer, which is deposited at 60 sccm. Mathematically, this results in 85nm for the pure HiPIMS layer. In a process according to the invention, however, 135 nm was achieved. This is due to the reduced nitrogen flow. Sputtering here is done more in a metallic fashion. Substoichiometric layers form. These can be seen in a lighter color as rings compared to the stoichiometric DCMS individual layers in the images of sections of the sample. The method according to the invention shows a significant increase in the coating rate compared to the pure HiPIMS method in the direction of the rate of the pulsed DCMS method. A reduction in the internal stress state compared to the HiPIMS process could be achieved. The higher rate is essentially due to the modulation of HiPIMS individual layers with DCMS individual layers as well as the changed reactive gas flow in the HiPIMS process.

The two exemplary embodiments shown, non-reactive process and reactive process, can of course also be combined combinatorially. An example would be the Cr/CrN system. The Cr layers could be deposited non-reactively with HiPIMS in order to achieve a particularly high density for a corrosion protection effect, whereas the hard CrN is deposited using DCMS to enable wear protection, or vice versa, depending on the desired property profile.

It is advantageous to vary reactive gases at least temporarily during coating for different layers. For example, layer architectures can be realized that contain a gradient with at least one element of the reactive gas or mixture, so that For example, starting with CrN, CrNO is initially created by adding O2 and CrO is formed as the top layer.

The invention is explained in more detail below using the schematic drawing and other very specific exemplary embodiments.

It shows in a schematic representation:

1 shows a known coating device with a process chamber, DC power supply and gas supply;

Fig. 2a shows a sequence of HiPIMS discharge pulses for deposition of the HiPIMS layer according to Fig. 2c;

2b shows a sequence of DCMS discharge pulses for depositing the DCMS layer according to FIG. 2c;

2c shows a simple exemplary embodiment of a layer system according to the invention produced with the pulse sequences according to FIGS. 2a and 2b;

3a shows a schematic of a rectangular HiPIMS or DCMS discharge pulse;

3b shows a schematic triangular HiPIMS or DCMS discharge pulse;

Fig. 3c shows a schematic of a needle-shaped HiPIMS or DCMS discharge pulse;

3d shows a schematic of a rectangular HiPIMS or DCMS discharge pulse according to FIG. 3a with a preparation pulse;

3e schematically shows a triangular HiPIMS or DCMS discharge pulse according to FIG. 3b with a positive square-wave pulse;

3f shows schematically a bipolar pulse sequence with needle-shaped discharge pulses; Fig. 4 Deposition rate as a function of magnetic field strength and pulse frequency.

For a better understanding of the invention, a coating device B known per se is shown below with reference to FIG Fig. 1 comprising a DC power supply 81 and a pulse unit 82, described schematically. At least the first power supply unit 7 must be designed and operable in such a way that the method according to the invention can be carried out by means of the magnetron 4, as will be explained in more detail below. The second power supply unit 8 can either be identical to the first power supply unit 7, or can also be different from the power supply unit 7, depending on which specific sputtering process is to be carried out with the magnetron 400.

At this point it should be expressly mentioned that in order to carry out a coating method according to the invention according to claim 1, for example to form a layer system S according to the invention according to FIG. 2c using pulse sequences according to FIGS. 2a and 2b, the second magnetron 400 with a second power supply unit is not required and therefore can also be missing, or operated with the same parameters as the first magnetron.

In the present specific example of a coating device B, the first power supply unit 7 is electrically connected to the magnetron 4, comprising a magnetic field source 41 and a primary target 42 with a coating material 43.

In the present special exemplary embodiment of FIG. 1, the magnetic field source 41 is designed such that a magnetic field strength MFS of Magnetic field source 41 during the pulsed and / or unpulsed DCMS sputtering process can be selected differently from a magnetic field strength MFS of the magnetic field source 41 during the HiPIMS sputtering process.

This can be done, for example, by means of a mechanical adjustment device, for example by means of a stepper motor or other mechanical adjustment units that are known to those skilled in the art, for example by determining a position and / or orientation of the magnetic field source 41 in relation to the magnetron 4 or in relation to the primary target 42 can be changed or adjusted, so that the magnetic field strength MFS at the location or in the vicinity of the magnetron 4 or the primary target 42 can be variably set to a predetermined value. Typical magnetic field strengths MFS are, for example, in the range from approx. 50Gauss to approx. WOOGauss. In practice, magnetic field strengths MFS in the range of approximately 50Gauss to 600Gauss are advantageously selected for the HiPIMS process, while typical magnetic field strengths MFS for the DCMS process are often in the range of approximately 300Gauss to WOOGauss.

Of course, it is also possible that, as an alternative or in addition to the previously described mechanical adjustment device, the magnetic field strength MFS can be varied in a manner known per se via an electromagnetic coil, which can be provided in the vicinity of the magnetron 4 and / or the primary target 42 a current through the electromagnetic coil can be changed or adjusted, so that the magnetic field strength MFS at the location or in the surroundings of the magnetron 4 or the primary target 42 can be variably adjusted to a predetermined value.

In principle, in addition to the previously mentioned options, other measures known to those skilled in the art can also be taken to change the magnetic field strength MFS at the location of the magnetron 4 or at the location of the primary target 42 during a coating step. For example around to produce a gradient layer and / or to optimally adjust the magnetic field strength MFS on the magnetron 4 and / or on the primary target 42 for carrying out the HiPIMS sputtering process and / or the DCMS sputtering process.

And of course it is also possible that, even with a further magnetron 400, if present, the strength of a magnetic field on the further magnetron 400 can also be adjusted as described above.

To deposit a HiPIMS layer HS, the first power supply unit 7 can provide a sequence consisting of a plurality of HiPIMS discharge pulses 5 of high power density with pulse duration TI in the operating state on the magnetron 4 for carrying out a HiPIMS sputtering method in a HiPIMS mode.

To deposit a DCMS layer DS on the substrate 1, the first power supply unit 7 can alternatively also be operated in a DCMS mode in a different operating state for carrying out a pulsed and/or non-pulsed DCMS sputtering process. The first power supply unit 7 is then operated in such a way that the magnetron 4 is operated with one or a plurality of DCMS discharge pulses 6 of low power density with a pulse duration T2 to form the DCMS layer. An unpulsed DCMS can also be selected.

The second power supply unit 8 is electrically connected to the magnetron 400 comprising a magnetic field source 401 and a primary target 402 with a coating material 403. In the operating state, the second power supply unit 8 can supply the second magnetron 400 with electrical energy in order to carry out a sputtering process in a manner well known to those skilled in the art.

In principle, it is possible for the second magnetron 400 to operate like the first by means of the second power supply unit 8 as described above Magnetron 4 is operated. However, it is also possible to operate the magnetron 400 according to any other sputtering method known per se, with or without the support of a magnetic field source 401.

1 in a HiPIMS mode, since only the first power supply unit 7 is in operation and only provides a sequence of HiPIMS discharge pulses 5 on the magnetron 4 or on the primary target 42, while the power supply unit 8 is not in operation.

The substrates 1 to be coated are advantageously, but not absolutely necessary in certain special cases, provided on a rotating substrate holder 9 in a manner known to those skilled in the art, so that a uniform coating of the substrates 1 can be ensured.

The rotating substrate holder 9 is here advantageous, but also fundamentally not necessary, connected to an electrical bias voltage supply 10, so that the rotating substrate holder 9 can be electrically biased to a predeterminable bias voltage.

In addition, the same or different sputtering gases 2, 21, 22 or predeterminable mixtures thereof can be supplied to the process chamber in a known manner. The sputtering gas 21 is used in the HiPIMS sputtering process, while the sputtering gas 22 is used to carry out the DCMS sputtering process.

Since the coating device B of FIG. 1 is currently operated in a HiPIMS mode, the process chamber 3 is flooded with the sputtering gas 21.

Examples of frequently used sputtering gases include noble gases such as argon or krypton or other known sputtering gases.

If the layer system S is to be deposited on the substrate 1 using a reactive sputtering process, which is the case in the specific example of FIG If this is the case, the process chamber can optionally be additionally supplied with the same or different process gases HPG, DCG or predeterminable mixtures thereof in a known manner. The process gas HPG is used in the HiPIMS sputtering process, while the process gas DCG is used to carry out the DCMS sputtering process.

Since the coating device B of FIG. 1 is currently operated in a HiPIMS mode, the process chamber 3 is flooded with the process gas HPG.

Examples of frequently used process gases include reactive gases such as C2H2, Ar, N2, O2 or other reactive gases known to those skilled in the art.

In principle, the magnetron 4 and the second magnetron 400 can comprise the same or different coating materials 43, 403. In addition, the coating device B according to FIG. 1 has a high vacuum pump system, which is not shown here for reasons of clarity. Particularly advantageously, but not necessarily, a radiation heater (also not shown here), which is known per se, for heating the substrates to be coated, as well as an AEGD module (Arc Enhanced Glow Discharge), which is also known per se, for ion cleaning of the substrates can also be provided.

2c of a very simple layer system S according to the invention was created using a coating device B according to FIG. 1 in a first process step in a HiPIMS sputtering process using the primary target 42 by depositing the HiPIMS layer HS from coating material 43 directly onto the substrate 1 deposited using a sequence consisting of a plurality of HiPIMS discharge pulses 5 of high power density with pulse duration TI according to FIG. 2a. In a second process step, the DCMS layer DS was then made from the same coating material 43 using one and the same primary target 42 in a pulsed DCMS sputtering process deposited on the HiPIMS layer in a DCMS mode by means of a sequence of a plurality of DCMS discharge pulses 6 of low power density with pulse duration T2 according to FIG. 2b.

The HiPIMS discharge pulses 5 of the sequence according to FIG. 2a are rectangular HiPIMS discharge pulses 5 with a pulse duration TI of 5 ms each, i.e. the DCMS duty cycle DUD of the individual DCMS discharge pulses 6 was 5 ms, and the HiPIMS discharge pulses 5 were in one A distance of 150ms, i.e. at a distance of a HiPIMS death time Ti of 150ms, is applied to the primary target 42. The HiPIMS duty cycle DUH of the sequence of HiPIMS discharge pulse 5 and HiPIMS death time Ti is therefore approx. 3.2%. The HiPMS layer HS of FIG. 2c was deposited with a large number of atomic layers within 60 s, which of course corresponds to the total duration of the sequence of HiPIMS discharge pulses 5 of high power density with pulse duration TI according to FIG. 2a. A partial sequence consisting of a HiPIMS duty cycle DUH of a single HiPIMS discharge pulse 5 and a HiPIMS death time Ti was a total of 155 ms, so that almost 400 individual HiPIMS discharge pulses 5 were used in the total coating time of 60 s, which corresponds to a pulse frequency of approx .6Hz, so that the entire duty cycle of the total coating time of around 60s also accounts for approx. 3.2%, since the pulse duration TI of the HiPIMS discharge pulses 5 and also the HiPIMS death time Ti were not changed during the entire coating process, which is of course possible in principle would be and is also practiced in special methods according to the invention. This means that to form the entire HiPIMS layer HS of FIG. 3c, the HiPIMS discharge pulses 5 were only switched on for approximately 3.2% of the total coating time of the HiPIMS layer HS.

A circular primary target 42 with a rather small area of approximately 30cm ² was used as the primary target 42. The applied rectangular sputtering voltage of the HiPIMS discharge pulses 5 was approx. 600V and the current of approx. 30A of the individual pulses was rectangular, so that a Pulse power of 18KW was achieved with each HiPIMS discharge pulse 5, which corresponds to a pulse power of 600W/cm ² on the primary target 42, as can be easily calculated.

As already mentioned, the DCMS layer DS was then applied to the HiPIMS layer HS in a DCMS sputtering process in a DCMS mode using a sequence consisting of a plurality of DCMS discharge pulses 6 of low power density with a pulse duration T2 according to FIG. 2b the coating material 43 is deposited directly onto the HiPIMS layer HS.

The DCMS discharge pulses 6 of low power density of the sequence of discharge pulses 6 according to FIG. 2b are rectangular DCMS discharge pulses 6 with a pulse duration T2 of 10Ops each, i.e. the DCMS duty cycle DUD of the individual DCMS discharge pulses 6 was 100ps and the DCMS Discharge pulses 6 were applied to the primary target 42 at a distance of 10ps, i.e. at a distance of a DCMS death time T2 of 10ps. The DCMS duty cycle DUD of the sequence of DCMS discharge pulse 5 and DCMS death time Ti is therefore approx. 90%. The DCMS layer DS of FIG. 2c was also deposited within 60 s, as can be seen from FIG. 2b, which of course corresponds to the total duration of the sequence of DCMS discharge pulses 6 of low power density with pulse duration T2 according to FIG. 2b. A partial sequence consisting of a duty cycle and a DCMS death time T2 was a total of 110ps, so that around 550,000 individual DCMS discharge pulses 6 were used in the total coating time of 60s, which corresponds to a pulse frequency of approx. 9kHz, so that the entire duty -Cycle of the total coating time of around 60s also accounts for approximately 90%, since the pulse duration T2 of the DCMS discharge pulses 6 and also the DCMS death time T2 were not changed during the entire coating process, which of course would be possible in principle and is also practiced in special methods according to the invention becomes. This means that to form the entire DCMS Layer DS of FIG. 2c, the DCMS discharge pulses 6 were switched on for approximately 90% of the total coating time of the DCMS layer DS.

As already mentioned, a circular primary target 42 with a rather small area of approximately 30cm ² was used as the primary target 42. The applied rectangular sputtering voltage of the DCMS discharge pulses 6 was approximately 500V and the current of approximately 1.3A of the individual pulses was also rectangular, so that a pulse power of around 600W was achieved with each DCMS discharge pulse 6, which was on the primary target 42 corresponds to a pulse power of 20W/cm ² , as can be easily calculated.

It should be noted that, as can be seen from FIG. different from what is the case in the prior art, where different power supply units must be used for the HiPIMS process and the DCMS process, which is the case, for example, with V.O. Oskirko et al. Can be read in Vacuum 181 (2020) 109670. When carrying out a method according to the invention, this can be done, for example, by the power supply unit 7 comprising a capacitor bank known per se for generating the HiPIMS discharge pulses 5 of high power density, which is then simply bypassed when switching to the DCMS mode by switching over a direct connection the DC power supply is made with the magnetron. As a result, the method according to the invention can not only be used to produce layer systems S with better properties than those known from the prior art, but the apparatus structure for carrying out a method according to the invention can also be significantly simplified.

It goes without saying that the primary target 42 does not necessarily have to be circular, but basically has any suitable geometry can. Layer systems S according to the invention, including those according to FIG. 2c, were produced, for example with rectangular primary targets 42.

In a special exemplary embodiment of a coating method according to the invention, the HiPIMS discharge pulses 5 and/or the DCMS discharge pulses 6 applied to the rectangular primary target 42 were triangular or needle-shaped discharge pulses 5, 6 with pulse durations in the range from a few ps to several 100 ms or even up to in the second range, for example if the DCMS layer DS is to be deposited in an unpulsed DCMS mode. The specific pulse duration to be selected is, as the person skilled in the art knows, determined by the type of discharge pulse (HiPIMS or DCMS discharge pulse) and depends on the coating material 43, the desired layer properties, such as hardness, E-modulus. Yield strength, adhesion strength, thermal stability of the layers to be produced, etc. Typical values for HiPIMS discharge pulses 5 are: Pulse duration of the HiPIMS discharge pulse 5 e.g. 80ps, dead time Ti between two HiPIMS discharge pulses 5 e.g. 1500ps, pulse frequency 63 Hz, duty cycle approx. 5%. Typical values for DCMS discharge pulses 6 are: Pulse duration of the DCMS discharge pulse 6 e.g. 1500ps, dead time T2 between two DCMS discharge pulses 6 e.g. 80ps, pulse frequency e.g. 630 Hz, duty cycle approx. 95%.

The person skilled in the art will readily understand that the schematically illustrated coating according to FIG. and in the case of a non-reactive sputtering process can also be produced without using reactive gases RG, RG1, RG2.

Furthermore, it goes without saying that in practice a layer system S according to the invention often has a plurality of sequences of the same or different HiPIMS layers, HS and DCMS layers deposited directly on top of one another DS can include and other, different types of layers, which are deposited using a different sputtering process, can also be provided between, below or above a sequence of HiPIMS and DCMS layer sequences deposited directly on one another.

And of course, the order of the deposited HiPIMS layers HS and DCMS layers DS can also be in the reverse order to that shown schematically in Fig. 2c, depending on the requirement or application. It is therefore entirely possible that the DCMS layer is first deposited in a sequence of different layers and then the HiPIMS layer HS is deposited on the DCMS layer DS.

It should be noted at this point that when “pulse shapes” are mentioned in the context of this application, i.e. rectangular, needle-shaped or triangular pulses, what is meant is the shape of the time course of the current of the discharge pulses. The applied voltage is usually always rectangular, but in special cases it can of course have any other suitable shape. For clarity, this situation will be briefly explained using FIGS. 3a to 3f.

3a to 3f show schematically some selected possible pulse shapes of current and voltage, which in practice have a particular significance for forming HiPIMS discharge pulses 5, but of course can also be used to form DCMS discharge pulses 6 and can be used advantageously when carrying out methods according to the invention. In the diagrams of FIGS. 3a to 3f, the negative target voltage U and the target current I are plotted on the ordinate upwards, while the time is plotted on the abscissa. The solid line U _p schematically represents the time course of the voltage and the dashed line l _p schematically represents the time course of the current of the HiPIMS discharge pulses 5 or the DCMS discharge pulses 6. In Fig. 3a, both the voltage U _p and the current l _p of the discharge pulse 5, 6 have a rectangular shape, which is why such pulses are referred to as rectangular discharge pulses. A typical triangular pulse is shown in Fig. 3b. The current l _p of the discharge pulse 5, 6 increases linearly over time t in the form of a ramp, while the voltage U _p has a rectangular shape. Fig. 3c shows two successive needle-shaped discharge pulses 5, 6. The current l _p rises rapidly as a function of time t in the form of a sharp needle to a peak value and then suddenly falls back to zero with voltage. The time course of the voltage U _p is again rectangular. 3d shows a schematic diagram of a rectangular discharge pulse according to FIG / or the reactive gases RG, RG1, RG2 can be achieved. 3e shows a further special pulse shape in which a first triangular discharge pulse 5, 6 according to FIG. 3b is followed by an oppositely polarized rectangular pulse with a positive voltage. Finally, Fig. 3f shows a so-called bipolar pulse sequence in which a reversed polarity needle-shaped pulse with positive voltage follows between two needle-shaped discharge pulses 5, 6 according to Fig. 3c.

All of these pulse shapes and also combinations and variants thereof, in addition to other pulse shapes known per se, which cannot all be shown in detail here for reasons of clarity, can be used advantageously in the context of a coating process according to the invention and the person skilled in the art understands which pulse shapes he has to select in order to produce a layer system S according to the invention with the desired properties.

The person skilled in the art will readily understand that all general and specific exemplary embodiments discussed in the context of this application vary depending on Application and requirement can also be suitably combined with one another and also other possible exemplary embodiments, which cannot all be presented in the context of this application for reasons of space, are also covered by the invention.

Claims

1 . Coating method for depositing a layer system (S) on a substrate (1), at least one HiPIMS layer (HS) and one DCMS layer (DS) being deposited on the substrate (1) by means of magnetron sputtering, and one using a sputtering gas (2, 21, 22) containing evacuable process chamber (3) with an anode and a magnetron (4) designed as a cathode, comprising a magnetic field source (41) and a primary target (42) with a coating material (43) is provided, characterized in that with one and the same primary target

(42) in any order and one after the other alternately the HiPIMS layer (HS) by a HiPIMS sputtering process in a HiPIMS mode using a sequence consisting of a plurality of HiPIMS discharge pulses (5) of high power density with a pulse duration (TI) of at least one Atomic layer is deposited from the coating material (43), and the DCMS layer (DS) is formed by a pulsed and / or unpulsed DCMS sputtering process in a DCMS mode using a DCMS discharge pulse (6) of low power density with pulse duration (T2). the DCMS layer (DS) made of the coating material

(43) is deposited.

2. Coating method according to claim 1, wherein in HiPIMS mode the power density of the HiPIMS discharge pulse (5) on the primary target (42) is in a range of 0.05kW/cm ² and 10kW/cm ² , preferably 0.1 kW/cm ² and 5kW/kW/cm ² , in particular from 0.2 kW/cm ² to 3 kW/cm ² , particularly preferably at approximately 0.4 kW/cm ² or 2 kW/cm ² , and/or where in HiPIMS mode in the sequence of HiPIMS discharge pulses (5), the pulse duration (TI) of the HiPIMS discharge pulse (5) is selected between 5ps and 20ms, preferably between 20ps and 10ms, in particular at approximately 50ps to 5ms.

3. Coating method according to one of the preceding claims, wherein in HiPIMS mode a HiPIMS death time (Ti) in the sequence of HiPIMS discharge pulses (5) between two successive HiPIMS discharge pulses (5) between 100ps and 500ms, preferably between 250ps and 250ms, in particular approximately 500ps and 150ms is selected, and / or a HiPIMS duty cycle (DUH) of a sequence of HiPIMS discharge pulse (5) and HiPIMS death time (T1) between 0.5% and 20%, preferably between 1% and 10%, particularly preferably between approximately 2% to 6% of the duration of the sequence of HiPIMS discharge pulse (5) and HiPIMS death time (T1) is selected and / or wherein in a sequence of HiPIMS discharge pulses (5) and HiPIMS dead time (Ti) the pulse duration (TI) of the HiPIMS discharge pulse (5) and / or the duration of the HiPIMS dead time (Ti) and / or the HiPIMS duty cycle (DUH) during the deposition of the layer system (S) is changed according to a predeterminable scheme.

4. Coating method according to one of the preceding claims, wherein in the DCMS mode the power density of the DCMS discharge pulse (6) on the primary target (42) is in a range of 1W/cm ² and 50W/cm ² , preferably between 2W/cm ² and 30W/cm ² , particularly preferably from approximately 5W/cm ² to 25W/cm ² , and/or wherein in the pulsed and/or non-pulsed DCMS mode the pulse duration (12) of the DCMS discharge pulse (6) is between 1 ps and 10ms, preferably between 5ps and 500ps, in particular at approximately 20ps or 200ps.

5. Coating method according to one of the preceding claims, wherein in the pulsed DCMS mode a DCMS death time (T2) in a sequence of DCMS discharge pulses (6) between two successive DCMS discharge pulses (6) between 0.5ps and 10ms, preferably between 2ps and 300ps, in particular at approx. 5ps to 100ps, and / or where a DCMS duty cycle (DUD) of a sequence of DCMS discharge pulse (5) and DCMS death time (T2) between 30% and 99%, preferably between 50% and 97%, particularly preferably at approximately 75% or 95% of the duration of the sequence of DCMS discharge pulse (5) and DCMS death time (T2), and / or wherein in a sequence of DCMS discharge pulses (6) and DCMS dead time (T2) the pulse duration (12) of the DCMS discharge pulse (6) and / or the duration of the HiPIMS dead time (T2) and / or the HiPIMS duty cycle (DUH) during the deposition of the Shift system (S) is changed according to a predeterminable scheme. Coating method according to one of the preceding claims, wherein the HiPIMS discharge pulse (5) of high power density and/or DCMS discharge pulse (6) of low power density is a rectangular and/or a triangular and/or a needle-shaped discharge pulse (5, 6), in particular is a bipolar discharge pulse (5, 6) or a bipolar sequence of discharge pulses (5, 6). Coating method according to one of the preceding claims, wherein the HiPIMS layer (HS) in HiPIMS mode using an HP process gas (HPG) and the DCMS layer (DS) in DCMS mode using one of the HP process gas (HPG) different DC process gas (DCG) is deposited, whereby a mixture of a plurality of different reactive gases (RG, RG1, RG2) is preferably used as the HP process gas (HPG) and / or as the DC process gas (DCG) and / or where during during the deposition of the HiPIMS layer (HS) in the HiPIMS mode, a composition of the HP process gas (HPG) and / or during the deposition of the DCMS layer (DS) in the DCMS mode, a composition of the DC process gas (DCG) is varied , and / or where during the deposition of the HiPIMS layer (HS) in the HiPIMS mode a partial pressure of the HP process gas (HPG) and / or during the deposition of the DCMS layer (DS) in the DCMS mode a partial pressure of the DC Process gas (DCG) is varied.

8. Coating method according to one of the preceding claims, wherein during the deposition of the HiPIMS layer (HS) in HiPIMS mode, an HP bias voltage (HPV) of the substrate (1) is different from a DC bias voltage (DCV). the deposition of the DCMS layer (DS) is selected in the DCMS mode and / or the HP bias voltage (HPV) is varied during the deposition of the HiPIMS layer (HS) in the HiPIMS mode and / or during the deposition the DCMS layer (DS) in DCMS mode, the DC bias voltage (DCV) of the substrate (1) is varied.

9. Coating method according to one of the preceding claims, wherein a magnetic field strength (MFS) of the magnetic field source (41) during the pulsed and / or unpulsed DCMS sputtering process is selected to be different from a magnetic field strength (MFS) of the magnetic field source (41) during the HiPIMS sputtering process.

10. Coating method according to one of the preceding claims, wherein a process time for producing the HiPIMS layer (HS) and / or the DCMS layer (DS) produced in an unpulsed and / or pulsed DCMS sputtering process is in the range from 0.5s to 10000s, preferably 1s to 5000s, in particular from approximately 5s to 2500s and / or where a ratio of the proportions of the sum of the layer thicknesses of the HiPIMS layers (HS) divided by the sum of the layer thicknesses of those produced in an unpulsed and / or pulsed DCMS sputtering process DCMS layers (DS) within the overall layer are in a range from 0.02 to 50, preferably in a range from 0.05 to 25, in particular in a range from 0.1 to 9 and / or wherein a thickness of the individual layers, which can be varied in a layer thickness, in a layer system (S) from the HiPIMS layers (HS) and the DCMS layers (DS) produced in an unpulsed and / or pulsed DCMS sputtering process in a range from 1 nm to 5000 nm, preferably in a range from 2 nm to 500 nm, in particular in a range from 5nm to 250nm.