Etching optimization process

Abstract

Method (2) for plasma-chemical cleaning of workpieces prior to coating using PVD and / or PECVD deposition technologies, comprising the following steps: - Applying (S1) a preferably homogeneous indicator coating to a substrate (4; 40; 42; 44; 46; 48, 50) whose three-dimensional shape corresponds to that of the workpiece to be coated; - Performing at least one (plasma) etching process (S2) in a coating chamber with a predetermined set of parameters on the substrate coated with the indicator coating (4; 40; 42; 44; 46; 48, 50); - Comparing (S3) a location-dependent / geometry-dependent coating thickness of the etched substrate (4; 40; 42; 44; 46; 48, 50) with a coating thickness of the untreated substrate (4; 40; 42; 44; 46; 48, 50); - Create (S4) at least one 3D etch profile from at least one comparison result; - Creating (S5) a customized parameter set depending on the at least one 3D etch profile achieved with the predetermined parameter set, with which a specific, in particular uniform, removal of the indicator coating could be achieved; and - Performing the (plasma) etching process (S6), preferably in the coating chamber, with the adapted parameter set on the workpiece.

Description

Technical area

[0001] The invention relates to a method for plasma-chemical cleaning of workpieces, such as cutting tools, before coating using PVD and / or PECVD deposition technologies.

[0002] From the document JP 2003- 171 785 A a method for removing a hard surface coating is known.

[0003] In addition, a method for etching a workpiece is known from the document DE 10 2014 110 275 A1.

[0004] Furthermore, from the document DE 10 2006 032 738 A1 a method for producing a structural body by means of an etching process and a device for carrying out a method are known.

[0005] When coating a workpiece using PVD (Physical Vapor Deposition) and PECVD (Plasma Enhanced Chemical Vapor Deposition), the adhesion between the coating and the workpiece results from the chemical bond between the atoms of the workpiece material and the atoms of the coating material. For this reason, the surface of the workpiece to be coated must be free of contaminants such as grease and / or oil residues. However, when a workpiece is exposed to the atmosphere, an undesirable oxide layer also forms on the workpiece surface, which can have a detrimental effect on adhesion. To obtain a contaminant-free surface at the atomic level, a process often referred to as plasma etching is used. This process involves bombarding the surface with inert gas ions in a high vacuum system. In this process, the glow discharge is ignited on the workpiece.Thus, glow discharge techniques used directly in the coating chamber before the PVD and PECVD processes are part of a common coating cycle.

[0006] A disadvantage of glow discharge techniques, however, is that the sputtering rate is geometry-dependent and can therefore be inhomogeneously distributed. Particularly on workpieces with complex geometries, an inhomogeneous sputtering rate distribution can arise on the surface of the respective workpiece, which in turn leads to geometry-dependent variations in the adhesion between the coating and the workpiece.

[0007] There are already efforts in the state of the art to suppress the inhomogeneous nature of the glow discharge technique. However, the resulting homogeneity of the glow discharge technique has so far only been evaluated using methods based on a profile measurement of a step between a shielded and an etched part of a planar sample. Thus, no method exists that can reliably determine the homogeneity of the glow discharge technique, allowing the evaluation of etching performance at specific, particularly highly stressed, areas of the workpiece to be coated.

[0008] Accordingly, the object of the present invention is to provide a method and a device for the plasma-chemical cleaning of workpieces, with which the quality of the plasma-chemical cleaning, i.e. the quality of an etching process, can be reliably assessed, so that the plasma-chemical cleaning can be optimized as a result of the assessment of the quality and can thus be achieved as homogeneously as possible, even with complex geometries, in a reliable and geometry-independent manner, in order to ensure sufficient adhesion of a coating applied to the cleaned workpiece.

[0009] The object of the invention is achieved by a method having the features of claim 1. Furthermore, the object of the invention is achieved by a device having the features of the independent claim. Advantageous further developments are the subject of the dependent claims.

[0010] Accordingly, the process for plasma-chemical cleaning of workpieces prior to coating using PVD and / or PECVD deposition technologies comprises the following steps: - applying a preferably homogeneous indicator coating to a substrate whose three-dimensional shape corresponds to that of the workpiece to be coated, - carrying out at least one (plasma) etching process, preferably in a coating chamber, with a predetermined set of parameters on the substrate coated with the indicator coating, - comparing a location-dependent / geometry-dependent coating thickness of the substrate processed by etching with a coating thickness of the unprocessed substrate, - Creating at least one 3D etching profile from the at least one comparison result, - Creating an adapted parameter set depending on the at least one 3D etching profile achieved with the predetermined parameter set, with which a specific, in particular uniform, removal of the indicator coating could be achieved, and - Carrying out the (plasma) etching process in the coating chamber with the adapted parameter set on the workpiece.

[0011] Thus, in a first process step, the indicator coating is applied to the substrate. This indicator coating is different from the final coating to be applied to the workpiece with sufficient adhesion. This means that the indicator coating only serves to determine / measure the efficiency / homogeneity of the subsequent (plasma) etching process on the (sample) substrate. The three-dimensional shape, i.e., the geometry, of the substrate must correspond to that of the workpiece to be coated in order to be able to transfer the significance of the geometry-dependent efficiency of a (plasma) etching process to the workpiece to be coated based on the geometry of the substrate.For example, it is also possible to use several (sample) substrates with different geometries, each corresponding to a section of the workpiece, in order to determine the efficiency only for certain sections of the workpiece or to combine the informative value of the several substrates, for example by superimposing or arranging the several substrates.

[0012] In a second process step, the substrate coated with the indicator coating is processed for plasma-chemical cleaning in the at least one (plasma) etching process, using a predetermined parameter set that determines the properties of the (plasma) etching process used and thus the etching performance. The predetermined parameter set may also be referred to below as a predetermined / first parameter profile. The (plasma) etching process is preferably carried out in the coating chamber in which the final coating is applied, in order to prevent the surface cleaned by the etching process from reacting with the environment.

[0013] Subsequently, in a third process step, the coating thickness of the indicator coating etched with the first parameter profile is compared with the coating thickness of the indicator coating prior to etching. In particular, location-dependent / geometry-dependent differences between individual areas of the substrate, such as weaker or barely etched areas, are identified.

[0014] In a fourth process step, a 3D etching profile is created by comparing the coating thicknesses before and after etching. This profile shows which coating thickness of the indicator coating was removed at which point on the substrate geometry by etching with the first parameter profile. In particular, it is possible to identify areas with high etching performance and which may need to be protected from over-etching, or areas with low etching performance and where sufficient cleaning was not achieved.

[0015] Then, in a fifth process step, a new / adapted parameter set, which is also referred to below as a second parameter profile, is generated. The second parameter profile can, for example, be modified compared to the first parameter profile in such a way that a desired, in particular uniform, removal of the indicator coating can be achieved on a substrate that has not yet been processed by etching, or on the final workpiece, or on the substrate that has already been etched with the first parameter profile. This means that it is possible to clean the already etched substrate in a further (plasma) etching process using the second / different parameter set in order to reach the areas of the substrate that have not yet been sufficiently etched. Likewise, it is also possible to clean another substrate provided with the unprocessed indicator coating with a second / different parameter set in order to reach every area of ​​a not yet etched substrate.In other words, the adapted parameter set may consist of combining / overlaying two predetermined parameter sets or modifying the predetermined parameter set.

[0016] Finally, in a sixth process step, the workpiece is processed in the (plasma) etching process with the second parameter profile, which is optimized compared to the predetermined parameter set.

[0017] According to a preferred embodiment, the indicator coating can be applied with a uniform coating thickness, i.e., uniformly, regardless of geometry. This has the advantage that, after performing the (plasma) etching process with the predetermined parameter set, it is easy to identify the areas of the substrate where a comparatively larger or smaller coating thickness has been removed. This means that, based on the coating remaining on the substrate, a direct statement can be made about the homogeneity of the (plasma) etching process with the predetermined parameter set, without having to calculate the original coating thickness based on the location.

[0018] According to a preferred embodiment, the indicator coating can have a coating thickness of up to a few micrometers, preferably a thickness of 30 to 150 nanometers, preferably 60 nanometers ± 20 nanometers. Such a coating thickness has proven suitable for exhibiting a clear interference color and ensuring that after performing the (plasma) etching process with the predetermined parameter set, a residual coating is still present on the substrate, based on which the etching performance can be assessed.

[0019] According to a preferred embodiment, the indicator coating can be a coating whose optical properties, in particular its color, change depending on its coating thickness. This means that the optical properties, in particular the indicator color, correspond directly to its coating thickness. This has the advantage that the coating thickness can be determined using an optical measuring method in a non-contact and non-destructive manner. Furthermore, the location-dependent / geometry-dependent differences in the achieved etching performance can also be easily and quickly identified manually / by the user, i.e., even without a measuring method.

[0020] According to the preferred embodiment, the optical properties, particularly the color, of the indicator coating can vary depending on its coating thickness in the range of ten nanometers. This means that thickness differences of ten nanometers can be visually detected, for example, by color differences. This allows the etching performance to be determined particularly reliably and precisely.

[0021] According to a preferred embodiment, the indicator coating can be an oxide layer, preferably a metal oxide layer, in particular a titanium oxide layer or chromium oxide layer. Such oxide layers have proven successful due to their homogeneity and their easy oxidization. The use of a titanium oxide layer is particularly advantageous because the oxidation / anodization of titanium has been very well researched. The thickness of the indicator coating, i.e., the upper oxidized part produced later, does not vary, even if the thickness of this layer on the substrate varies due to the geometry dependence of the PVD coating techniques. Preferably, the minimum thickness of the titanium base layer is greater at all locations on the substrate than the thickness of the titanium oxide layer produced in the following step.

[0022] According to a preferred embodiment, the indicator coating can be applied by oxidation and / or anodization and / or anodizing. Preferably, the indicator coating can be applied in the coating chamber. It is possible to carry out the oxidation process directly in the coating chamber using oxygen discharge, while the substrate is at floating potential and the temperature of the substrate is 550±30 degrees C. Floating potential can, for example, be understood as a voltage range from -5V to -20V. The floating potential is necessary to prevent the inhomogeneous surface reaction caused by the antenna effect. To carry out such a process, the substrate cannot be used as a cathode, as is typical for the glow discharge techniques of plasma etching, so an external ionization source is required.Furthermore, the presence of oxygen and oxygen discharges in the coating chamber is often undesirable, especially at high temperatures, as the oxygen can react with other parts of the coating chamber. This can negatively affect the conductivity between the parts of the coating chamber, and later, during a different coating process, the desorption of oxygen could impair the properties of the coating. Alternatively, the standard anodizing process (especially titanium anodizing) can be performed outside the coating chamber in a special acid bath while a specific positive voltage is applied to the substrate.

[0023] According to a preferred embodiment, the (plasma) etching process can be carried out on the substrate coated with the indicator coating for a predetermined substrate etching time, and the (plasma) etching process can be carried out on the workpiece for a predetermined workpiece etching time. The predetermined workpiece etching time can preferably be several times longer than the predetermined substrate etching time, in particular by twice or three times up to five times or six times. The predetermined substrate etching time is preferably selected depending on the coating thickness of the indicator coating such that the indicator coating is reduced at every point after etching over the predetermined substrate etching time, but not at every point, or in particular, is not completely removed at any point.This means that to etch the indicator layer, a substrate etching time is initially used that must be long enough to cause a change in the optical property, i.e., a color change is visible, but small enough so that the indicator layer is not completely removed at every point (and may be "over-etched" in some places) in order to be able to make a statement about geometry-dependent / regional differences. For the workpiece etching time, a longer time is selected depending on the geometry and / or size of the workpiece and the severity of the contamination. For example, the predetermined substrate etching time can be between 5 and 10 minutes, while the predetermined workpiece etching time can be between 5 and 60 minutes, preferably between 30 and 60 minutes.

[0024] According to a preferred embodiment, an etching technology used can be a parameter of the predetermined parameter set. Preferably, a standard glow discharge, an enhanced glow discharge, such as a glow discharge assisted by electrons from the side-arc cathode, and / or metal ion etching, ie, ionized material vaporized by the arc cathode is accelerated onto the substrate, can be used as the etching technology.

[0025] According to a preferred embodiment, the predetermined workpiece etching time may be between 5 and 60 minutes for standard glow discharge, between 5 and 60 minutes for enhanced glow discharge, and between 5 and 30 minutes for metal ion etching.

[0026] According to a preferred embodiment, the argon pressure used in the coating chamber can be a parameter of the predetermined parameter set. Preferably, the argon pressure can be between 0.5 and 6.0 Pascal for standard glow discharge and enhanced glow discharge, and between 0.1 and 0.6 Pascal for metal ion etching.

[0027] According to a preferred embodiment, a voltage applied to the substrate can be one of the predetermined parameter sets. Preferably, the voltage can be between 500 and 750 volts for standard glow discharge, between 200 and 500 volts for enhanced glow discharge, and between 700 and 1200 volts for metal ion etching.

[0028] According to a preferred embodiment, a temperature in the coating chamber can be one of the predetermined parameter sets. Preferably, the temperature can be between 100 and 600°C for standard glow discharge, between 200 and 600°C for enhanced glow discharge, and between 200 and 600°C for metal ion etching.

[0029] According to a preferred embodiment, the loading / assembly and / or positioning of a substrate carrier in the coating chamber can be a parameter of the predetermined parameter set. Since the substrates shield each other at higher loadings, the loading has a direct influence on the etching performance.

[0030] According to a preferred embodiment, a pulse type can be a parameter of the predetermined parameter set. Preferably, direct current and pulsed operation can be pulse types.

[0031] According to a preferred embodiment, an electron current on the fed anode can be one of the predetermined parameter sets. Preferably, the electron current can be between 40 and 85 amperes.

[0032] According to a preferred embodiment, a voltage on the supplied anode can be a parameter of the predetermined parameter set. Preferably, the voltage can be between 20 and 60 volts.

[0033] According to a preferred embodiment, a current from the arc cathode can be one of the predetermined parameter sets. Preferably, the current can be between 60 and 120 amperes.

[0034] According to a preferred embodiment, a plurality of geometries / partial geometries and a plurality of parameter profiles, i.e., at predetermined parameter sets, can be stored in a database. Preferably, in a method step preceding the execution of the at least one (plasma) etching process with the predetermined parameter set, the substrate can be compared with the plurality of geometries / partial geometries, and based on the geometry comparison, a suitable parameter profile can be selected with which the (plasma) etching process is carried out on the substrate. This means that it is possible to learn from previously coated substrate geometries, in particular by means of artificial intelligence, which parameter profile is suitable for which geometry to be coated, so that the etching performance can be further optimized with each coating pass for known geometries and any iteration processes can be eliminated.

[0035] The object of the invention is also achieved by a device for carrying out plasma-chemical cleaning of workpieces prior to coating using PVD and / or PECVD deposition technologies, comprising a means for applying a preferably homogeneous indicator coating to a substrate whose three-dimensional shape corresponds to that of the workpiece to be coated; a means for carrying out at least one (plasma) etching process with a predetermined set of parameters on the substrate coated with the indicator coating; a means for comparing the location-dependent / geometry-dependent coating thickness of the substrate processed by etching with the coating thickness of the unprocessed substrate; a means for creating at least one 3D etching profile from the at least one comparison result;a means for creating an adapted parameter set depending on the at least one 3D etching profile achieved with the predetermined parameter set, with which a uniform removal of the indicator coating can be achieved; and a means for carrying out the (plasma) etching process with the adapted parameter set on the workpiece.

[0036] In other words, the method according to the invention can provide a visual three-dimensional profile of the plasma etching effect at any point on a surface of any shape. No other method is currently capable of providing a 3D-resolved plasma etching rate on a substrate of any geometry. Thus, with the complete, visual, three-dimensional profile, the cleaning efficiency of plasma etching techniques can be determined in order to improve efficiency. For example, substrates of any shape (e.g., cutting tools) can be covered with a layer exhibiting a homogeneous interference color or a self-supporting film exhibiting a homogeneous interference color before the plasma etching process in order to obtain such three-dimensional, resolved etching profiles. The color of a thin oxide layer, such as a titanium oxide layer, varies depending on its thickness on a scale of tens of nanometers.While the anodization / oxidation process is geometry-independent, the plasma etching process is geometry-dependent. The substrates covered with the film can be placed in the coating chamber, allowing the plasma etching process to be carried out with a predetermined set of parameters, e.g., for a predetermined time. Etching causes the thickness of the thin layer on the substrate surface to decrease unevenly. Since the interference color of the indicator coating corresponds directly to its thickness, the resulting color at any point on the surface provides information about the etching effect at that location.This means that the inventive idea is to use the homogeneous interference layers for 3D profiling of the plasma etching performance, so that the adhesion of the coating on substrates of any geometry, in particular on tools, molds or components with grooves, cavities, negative curvatures and different aspect ratios, can be optimized, which is not possible with conventional one-dimensional or two-dimensional measuring methods with such a high resolution, i.e. 3-D profile measurement with a resolution of approximately ± 5 nm.

[0037] The invention is explained below with reference to the figures. They show: Fig. 1 a schematic block diagram of a method according to the invention; Fig. 2 a side view of a first substrate, the shape of which corresponds to a first workpiece to be coated, at different times of the process; Fig. 3a and Fig. 3b a view of a second substrate at different times of the process; Fig. 4a and Fig. 4b a view of a third substrate at different times of the process; Fig. 5a to 5c show a side view of the first substrate on which the process was carried out with different sets of parameters; Fig. 6 a side view of the first substrate after carrying out the method with several different parameter sets; Fig. 7a to 7c show different views of a fourth substrate at different times of the process; Fig. 8a to 8c show different views of a fifth substrate at different times of the process; Fig. 9a to 9c show different views of a sixth substrate at different times of the process; and Fig. 10a to 10c show different views of a seventh substrate at different times of the process. Fig. 11 shows a schematic view or a block diagram of an apparatus 52 for carrying out the Fig. 1 shown procedure.

[0038] Fig. 1 shows a schematic block diagram of a method 2 according to the invention. The method 2 is used for the plasma-chemical cleaning of workpieces before coating using PVD and / or PECVD deposition technologies.

[0039] In a first method step S1, an indicator coating is applied to a substrate. The substrate has a geometry / three-dimensional shape that corresponds to that of the workpiece to be coated. Preferably, the in particular homogeneous indicator coating can be applied uniformly, i.e. with the same coating thickness, regardless of the geometry of the substrate. For example, the indicator coating has a coating thickness of up to a few micrometers, preferably a coating thickness of 30 to 150 nanometers, preferably 60 nanometers ± 20 nanometers. The indicator coating can be a coating whose optical properties, in particular its color, change depending on its coating thickness. Thickness differences in the range of ten nanometers can be optically detected by color differences.

[0040] For example, the indicator coating can be an oxide layer, preferably a metal oxide layer, in particular a titanium oxide layer or chromium oxide layer. The indicator coating can be applied to the substrate by oxidation and / or anodization and / or anodization. In particular, a base layer (e.g., made of titanium) is applied to the substrate, and this base layer is oxidized, anodized, or anodized, respectively, thereby creating a homogeneous and geometry-independent oxide layer (e.g., made of titanium) on the substrate, the thickness of which can be determined by the color of the oxide layer.

[0041] In a second method step S2, at least one (plasma) etching process is carried out in a coating chamber using a predetermined set of parameters on the substrate coated with the indicator coating. In particular, the substrate coated with the indicator coating is processed by the (plasma) etching process for a predetermined substrate etching time using the predetermined set of parameters, wherein the predetermined substrate etching time is different from a predetermined workpiece etching time with which the (final) workpiece is processed. Preferably, the predetermined substrate etching time is selected depending on the coating thickness of the indicator coating such that the indicator coating is reduced at every point after etching over the predetermined substrate etching time, but is not removed at every point or, in particular, is not completely removed at any point.For example, the predetermined substrate etching time may be shorter, such as 2 or 3 times to 5 or 6 times shorter, than the predetermined workpiece etching time.

[0042] In a third method step S3, a location-dependent or geometry-dependent coating thickness of the substrate processed by etching is compared with the coating thickness of the unprocessed substrate or with a previously (empirically) determined (color) scale, so that in particular location-dependent differences in the etching performance achieved by the predetermined parameter set are identified.

[0043] In a fourth process step S4, a 3D etching profile is created by comparing the coating thicknesses before and after etching. The 3D etching profile depicts, in particular for the predetermined parameter set, which geometric regions of the substrate exhibit particularly high / highest etching power and which geometric regions of the substrate exhibit particularly low / lowest etching power.

[0044] In a fifth method step S5, an adapted parameter set is created depending on the at least one 3D etching profile achieved with the predetermined parameter set, with which a specific, in particular uniform, removal of the indicator coating could be achieved. For example, to create the adapted parameter set, two (or more) different predetermined parameter sets can be combined (or two (or more) etching processes with the respective predetermined parameter sets can be carried out one after the other) in order, for example, to superimpose a 3D etching profile that has a low etching power in the first regions with another 3D etching profile that has a particularly high or comparatively high etching power in the first regions.The adjusted parameter set can also be selected so that the etching profile achieved thereby provides a comparatively high etching performance in the more highly stressed areas, such as in the area of ​​cutting edges, or so that the etching profile achieved thereby provides a uniform etching performance in all areas.

[0045] In a sixth method step S6, the (plasma) etching process is carried out on the workpiece, preferably in the coating chamber, using the adapted parameter set. In particular, the (plasma) etching process is carried out on the workpiece using the adapted parameter set for the predetermined workpiece etching time, which, as described above, can be longer than the predetermined substrate etching time.

[0046] In Fig. For better understanding, Figure 2 shows an embodiment of the method 2 according to the invention, in which a first substrate 4, more precisely a (twist) drill, is depicted at different times during the method 2. The first substrate 4 has a geometry / three-dimensional shape that corresponds (at least in sections) to that of a first workpiece to be coated.

[0047] In an upper part of the Fig. 2, the first substrate 4 is shown at a time between the first method step S1 and the second method step S2. The substrate 4 has a cutting section 6 and a shank section 8. The cutting section 6 has a plurality of secondary cutting edges 10 extending helically over the cutting section 6, to which an associated drill web 12 adjoins on one side in the circumferential direction and to which an associated chip groove 14 adjoins on the other side in the circumferential direction. The cutting section 6 is provided with the indicator coating with a constant coating thickness, independent of the geometry. This can be seen from the fact that the cutting section 6 has the same optical property, in particular color, in every area, which in Fig. 2 is represented by the uniform dotted filling. The shaft section 8 is not coated with the indicator coating.

[0048] In a central part of the Fig. Figure 2 shows the first substrate 4 after the second method step S2, in which the substrate 4 was processed with the predetermined parameter set for the predetermined substrate etching time. It can be seen here that the indicator coating has locally / regionally different optical properties, in particular colors, which is Fig. 2 is represented by the differently dotted filling. In particular, it can be seen that the indicator coating is thinnest in the area of ​​the secondary cutting edges 10, thicker on an outer peripheral surface in the area of ​​the drill lands 12 than in the area of ​​the secondary cutting edges 10, and thickest in the area of ​​the chip grooves 14, which can be seen from the different fillings. This means that the greatest etching power has been achieved in the area of ​​the secondary cutting edges 10 and the lowest etching power has been achieved in the area of ​​the chip grooves 14.

[0049] In a lower part of the Fig. 2 shows a scale 20 that assigns a coating thickness to the optical properties of the indicator coating. For illustrative purposes, different dot densities in the Fig. 2 different colors. Thus, areas 22, which have a corresponding dot density shown on scale 20, have a thickness of 0 to 10 nanometers; areas 24, which have a corresponding dot density shown on scale 20, have a thickness of 10 to 20 nanometers; areas 26, which have a corresponding dot density shown on scale 20, have a thickness of 20 to 35 nanometers; areas 28, which have a corresponding dot density shown on scale 20, have a thickness of 35 to 50 nanometers; and areas 30, which have a corresponding dot density shown on scale 20, have a thickness of 50 to 80 nanometers.

[0050] In comparison with scale 20 it can be seen that the indicator coating before etching is everywhere in the cutting area 6 in Fig. 2 has a thickness of the regions 30, in particular a thickness of 56 ± 5 nm. After etching, the indicator coating has a thickness of the regions 22 on the peripheral cutting edges 10, in particular a thickness of 5 ± 5 nm, a thickness of the regions 24 on the drill lands 12, in particular a thickness of 15 ± 5 nm, and a thickness of the regions 28 on the chip grooves 14, in particular a thickness of 39 ± 5 nm.

[0051] Fig. 3a and Fig. 3b show a second substrate 40 in the form of a circular cylindrical plate, in which, before etching (cf. Fig. 3a) there is a thickness of the areas 30 everywhere and after etching (cf. Fig. 3b) predominantly a thickness of the areas 28 and only in the area of ​​an upper edge a thickness of the area 24 is present.

[0052] Fig. 4a and Fig. 4b show a third substrate 42 in the form of a triangular plate, in which, before etching (cf. Fig. 4a) there is a thickness of the areas 30 everywhere and after etching (cf. Fig. 4b) predominantly a thickness of the regions 28 is present, which continuously decreases towards their outer edges over a thickness of the regions 26, 24, 22 and 20.

[0053] Fig. Figures 5a to 5c show the first substrate 4 on which the process was carried out with different parameter sets. It can be seen that in the Fig. 5a, a parameter set was selected with which, in particular, only the secondary cutting edges 10 were etched, in which Fig. 5b, a parameter set was selected with which the etching power decreases from a tip to the shaft section 8 and is weakest in the central area of ​​the chip grooves 14, and that the Fig. 5c, a parameter set was selected with which the etching power decreases from a tip to the shaft section 8 and is weakest in the area of ​​the chip grooves 14 directly adjacent to the secondary cutting edges 10.

[0054] Fig. Figure 6 shows the first substrate after performing the process with several different parameter sets or an adapted parameter set. The substrate has been completely etched and no longer has any areas with a residual indicator coating. Thus, for a workpiece whose geometry corresponds to that of the first substrate 4, all contaminants can be removed with the adapted parameter set.

[0055] Fig. 7a to 7c show a fourth substrate 44 in which, before etching (cf. Fig. 7a) there is a thickness of the areas 30 everywhere and after etching (cf. Fig. 7b and 7c) there are locally significant differences, wherein in particular recessed sections of the fourth substrate 44 have a greater residual coating thickness after etching, approximately a thickness in the region 28, and exposed sections of the fourth substrate 44 have almost no residual coating thickness after etching, approximately a thickness in the region 22.

[0056] Fig. 8a to 8c show a fifth substrate 46 in the form of an indexable insert, which is accommodated in a substrate carrier carousel. In the fifth substrate 46, prior to etching (cf. Fig. 8a) everywhere a thickness of the areas 30 before and after etching (cf. Fig. 8b or 8c) predominantly provide a thickness of the regions 28 which decreases towards their outer edges to a thickness of the region 26.

[0057] Fig. 9a to 9c show a sixth substrate 48 in the form of a gearwheel, which is accommodated in a substrate carrier carousel. In the sixth substrate 48, prior to etching (cf. Fig. 8a) everywhere a thickness of the areas 30 before and after etching (cf. Fig. 9b or 9c) predominantly provide a thickness of the regions 28 which decreases towards their outer edges to a thickness of the region 24, wherein the outer surfaces of the gear have a thickness of the region 26.

[0058] Fig. 10a to 10c show a seventh substrate 50 in which, before etching (cf. Fig. 10a) there is a thickness of the areas 30 everywhere and after etching (cf. Fig. 10b or 10c) predominantly a thickness of the regions 28 is present, which continuously decreases outwards over a thickness of the regions 26 and 24 to a thickness of the region 22.

[0059] Fig. 11 shows a schematic view or a block diagram of an apparatus 52 for carrying out the Fig. 1 shown procedure.

[0060] The device 52 is used to perform plasma-chemical cleaning of workpieces prior to coating using PVD and / or PECVD deposition technologies. The device 52 has a (first) means 54 for applying the preferably homogeneous indicator coating to the substrate, whose three-dimensional shape corresponds to that of the workpiece to be coated. Furthermore, the device 52 has a (second) means 56 for performing the at least one (plasma) etching process with the predetermined parameter set on the substrate coated with the indicator coating. Furthermore, the device 52 has a (third) means 58 for comparing the location-dependent / geometry-dependent coating thickness of the substrate processed by etching with the coating thickness of the unprocessed substrate. In addition, the device 52 has a (fourth) means 60 for creating the at least one 3D etching profile from the at least one comparison result.The device 52 further comprises a (fifth) means 62 for creating the adapted parameter set as a function of the at least one 3D etching profile obtained with the predetermined parameter set, with which a specific, in particular uniform, removal of the indicator coating can be achieved. Furthermore, the device 52 comprises a (sixth) means 64 for carrying out the (plasma) etching process on the workpiece with the adapted parameter set.

Claims

[1] Process (2) for the plasma-chemical cleaning of workpieces prior to coating using PVD and / or PECVD deposition technologies, comprising the following steps: - applying (S1) a preferably homogeneous indicator coating to a substrate (4; 40; 42; 44; 46; 48, 50) whose three-dimensional shape corresponds to that of the workpiece to be coated; - carrying out at least one (plasma) etching process (S2) in a coating chamber with a predetermined set of parameters on the substrate (4; 40; 42; 44; 46; 48, 50) coated with the indicator coating; - comparing (S3) a location-dependent / geometry-dependent coating thickness of the substrate (4; 40; 42; 44; 46; 48, 50) processed by etching with a coating thickness of the unprocessed substrate (4; 40; 42; 44; 46; 48, 50); - creating (S4) at least one 3D etching profile from the at least one comparison result; - creating (S5) an adapted parameter set depending on the at least one 3D etching profile achieved with the predetermined parameter set, with which a specific, in particular uniform, removal of the indicator coating could be achieved; and - Carrying out the (plasma) etching process (S6), preferably in the coating chamber, with the adapted parameter set on the workpiece. [2] Method (2) according to claim 1, characterized by that the indicator coating is applied evenly / with the same coating thickness regardless of the geometry. [3] Method (2) according to claim 1 or 2, characterized by that the indicator coating has a coating thickness of up to a few micrometers, preferably a thickness of 30 to 150 nanometers, preferably 60 nanometers ± 20 nanometers. [4] Method (2) according to one of claims 1 to 3, characterized bythat the indicator coating is a coating whose optical properties, in particular its colour, change depending on its coating thickness, in particular in the range of ten nanometres. [5] Method (2) according to one of claims 1 to 4, characterized by that the indicator coating is an oxide layer, preferably a metal oxide layer, in particular a titanium oxide layer or chromium oxide layer, wherein the indicator coating is applied by oxidizing and / or anodizing and / or anodizing. [6] Method (2) according to one of claims 1 to 5, characterized bythat the (plasma) etching process is carried out on the substrate (4; 40; 42; 44; 46; 48, 50) coated with the indicator coating for a predetermined substrate etching time and the (plasma) etching process is carried out on the workpiece for a predetermined workpiece etching time, wherein the predetermined workpiece etching time is preferably many times, in particular twice or three times up to five times or six times, longer than the predetermined substrate etching time, wherein the predetermined substrate etching time is between 5 and 10 minutes and / or the predetermined workpiece etching time is between 5 and 60 minutes, preferably between 30 and 60 minutes. [7] Method (2) according to one of claims 1 to 6, characterized by that an etching technology used is a parameter of the predetermined parameter set, wherein a standard glow discharge, an enhanced glow discharge and metal ion etching can be used as etching technology. [8] Method (2) according to claim 7, characterized by that the predetermined workpiece etching time is between 5 and 60 minutes for standard glow discharge, between 5 and 60 minutes for enhanced glow discharge and between 5 and 30 minutes for metal ion etching. [9] Method (2) according to one of claims 1 to 8, characterized by that an argon pressure used in the coating chamber is a parameter of the predetermined parameter set, wherein the argon pressure is between 0.5 and 6.0 Pascal for the standard glow discharge and the enhanced glow discharge and between 0.1 and 0.6 Pascal for the metal ion etching. [10] Method (2) according to one of claims 1 to 9, characterized bythat a voltage applied to the substrate (4; 40; 42; 44; 46; 48, 50) is a parameter of the predetermined set of parameters, the voltage being between 500 and 750 volts for the standard glow discharge, between 200 and 500 volts for the enhanced glow discharge and between 700 and 1200 volts for the metal ion etching. [11] Method (2) according to one of claims 1 to 10, characterized by that a temperature in the coating chamber is a parameter of the predetermined set of parameters, the temperature being between 100 and 600°C for the standard glow discharge, between 200 and 600°C for the enhanced glow discharge and between 200 and 600°C for the metal ion etching. [12] Method (2) according to one of claims 1 to 11, characterized by that a loading / assembly in the coating chamber is a parameter of the predetermined parameter set. [13] Method (2) according to one of claims 1 to 12, characterized bythat a pulse type is a parameter of the predetermined parameter set, where direct current and pulsed operation are pulse types. [14] Method (2) according to one of claims 1 to 13, characterized by that an electron current on the fed anode is a parameter of the predetermined parameter set, wherein the electron current is preferably between 40 and 85 amperes. [15] Method (2) according to one of claims 1 to 14, characterized by that a voltage on the supplied anode is a parameter of the predetermined parameter set, wherein the voltage is preferably between 20 and 60 volts. [16] Method (2) according to one of claims 1 to 15, characterized by that a current from the arc cathode is a parameter of the predetermined parameter set, wherein the current is preferably between 60 and 120 amperes. [17] Device (52) for carrying out a plasma-chemical cleaning of workpieces prior to coating by means of PVD and / or PECVD deposition technologies, comprising - a means (54) for applying a preferably homogeneous indicator coating to a substrate (4; 40; 42; 44; 46; 48, 50) whose three-dimensional shape corresponds to that of the workpiece to be coated; - a means (56) for carrying out at least one (plasma) etching process with a predetermined set of parameters on the substrate (4; 40; 42; 44; 46; 48, 50) coated with the indicator coating; - a means (58) for comparing the location-dependent / geometry-dependent coating thickness of the substrate (4; 40; 42; 44; 46; 48, 50) processed by etching with the coating thickness of the unprocessed substrate (4; 40; 42; 44; 46; 48, 50); - means (60) for creating at least one 3D etching profile from the at least one comparison result; - a means (62) for creating an adapted parameter set depending on the at least one 3D etching profile achieved with the predetermined parameter set, with which a specific, in particular uniform, removal of the indicator coating could be achieved; and - a means (64) for carrying out the (plasma) etching process with the adapted parameter set on the workpiece.

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