Method for operating a pulsed arc evaporation source and vacuum process system comprising said pulsed arc evaporation source

The present invention relates to a hard material film precipitated as an oxide arc-PVD functional film (32) on a work piece (30) according to the superordinate concept of claim 1.

The operation of an arc-deposited source, also known as an arc cathode, by supplying an electron pulse has been known in the art for quite some time. Highly efficient deposition rates and thus high deposition rates can be achieved during coating using arc deposition sources. Moreover, the structure of this type of source is technically relatively easy to implement. This source typically operates in the range of about 100 A or more at currents that can be achieved with relatively inexpensive DC power supplies and from a few volts to 10 volts at voltage. An essential drawback of these sources is the very fast progress of melting on the target surface within the cathode point, which forms droplets, so-called droplets, which are ejected as droplets. In addition, it condenses on the work piece and therefore adversely affects the film properties. For example, this causes the film structure to become non-uniform and the surface roughness to deteriorate. When the demand for film quality is high, the film thus obtained cannot often be used as a commercial product. Therefore, mitigation of this problem has already been attempted by operating the arc deposition source in pure pulse operation of the power supply. However, this has so far only achieved a unique improvement in droplet formation.

The use of reaction gases for precipitation of compounds from metal targets in reactive plasmas has traditionally been limited only to the production of electrically conductive films. The problem of droplet formation is increasing in the production of non-conductive, i.e., dielectric films such as oxides in the use of oxygen as the reaction gas. The recoating (Wiederbelegung) of the target surface and counter electrode of the arc deposition equipment, such as the anode and also other parts of the vacuum processing equipment, with a non-conductor film, which is always associated with the process in this case, is a completely unstable situation of arc discharge. And, on the contrary, it causes disappearance. In this case the arc discharge would have to be reignited repeatedly in such cases, or the process would be totally impossible to carry out.

European Patent No. 0666335 states that for the precipitation of purely metal materials using an arc deposition apparatus, this DC basic current is reduced by superimposing a pulsed current on the DC to reduce droplet formation. It has been proposed that In this case, a pulse current up to 5000A, which must be generated by capacitor discharge at a relatively low pulse frequency in the range of 100Hz to 50kHz, is required. This procedure has been proposed to prevent droplet formation in the case of non-reactive deposition of purely metal targets using an arc deposition source. No solution for non-conductor, or dielectric coatings, is shown in this document.

Reactive coatings with an arc-deposited source lack reactivity and process stability, especially in the production of insulating films. Unlike other PVD processes (eg, sputtering), the insulating film can be produced by arc deposition using only conductive targets. Operations using high frequencies, as is the case with sputtering, for example, have traditionally failed due to a flaw in the technology capable of operating large current sources with high frequencies. Operation with a pulsed power supply seems to be an option. However, in that case, the arc as described above must be repeatedly ignited, or the pulse frequency must be selected so large that the arc disappears. This appears to work for special materials, for example in applications with graphite, such as German Federal Patent No. 3,901,401. However, graphite is not an insulator and is electrically conductive even if it has poorer conductivity than ordinary metals.

In the case of an oxidized target surface, new ignition is not possible through mechanical contact and using a DC power source. The original problem with reactive arc deposition is coating with an insulating film on the target and the anode or coating chamber connected as the anode. This insulating coating increases the burning voltage of the spark discharge during the course of its formation, causing an unstable process that ends with increased splash and flashover, interruption of the spark discharge. The target coating involves island growth that reduces the conductive surface. A significantly dilute reaction gas (eg, an argon / oxygen mixture) can slow growth at the target, but does not eliminate the underlying problem of process instability. The proposal by US Pat. No. 5,103,766, in which the cathode and anode are operated with alternating fresh firings each time, contributes significantly to process stability, but increases droplets.

For example, the breakthrough with a pulsed power source, which is possible in the case of reaction sputtering, cannot be performed by typical arc deposition. This is due to the fact that glow discharges "live longer" than arcs when power is interrupted. In the case of a reactive process to produce an insulating film, the reactive gas inlet is spatially separated from the target to avoid the problem of coating the target with the insulating film (where the reactivity of the process is substrate. The temperature is also only guaranteed if it allows oxidation / reaction) or the droplets and ionized parts are separated (so-called filtered arc), and the reaction gas is added to the ionized vapor after filtering. Will be done.

In addition, there is a demand for further reduction or adaptation of the thermal load of the substrate, and there is the possibility of performing a low temperature process in the cathode arc coating. Pamphlet No. 03018862 describes pulsed operation of the plasma source as one possible way to reduce the thermal load on the substrate. However, the rationale for the area of the sputtering method is sufficiently valid in that document. It is manufactured independently of arc deposition.

For the scope of application of hard material coatings, there is a particular need to be able to produce oxidized hard materials with the corresponding hardness, adhesion strength and controlled desired tribological properties. One important role could be played here by aluminum oxide, especially chromium oxide. PVD (Physical Vapor) Previous techniques in the field of Deposition Physical Vapor Deposition) have mostly addressed here only the production of γ-aluminum oxide and α-aluminum oxide. The method often mentioned is dual magnetron sputtering, which has major drawbacks in this application in terms of process reliability and cost. Japanese patents concentrate on the coating system connected to the tool and cite the arc ion plating method as the manufacturing method. The general desire is to be able to precipitate α-aluminum oxide. However, for that reason, the conventional PVD method requires a substrate temperature of about 700 ° C. or higher to obtain this structure. Some users have tried to avoid this high temperature in a sophisticated way by nucleation membranes (TiAlN, Al-Cr-O-based oxidation). However, this does not necessarily make this process relatively inexpensive and fast. To date, it has been considered impossible to satisfactorily produce α-aluminum oxide films using arc deposition.

The following drawbacks are briefly described with respect to the prior art, especially with respect to the production of oxide films by reactive processes. 1. Arc vapor deposition of arc discharge Without spatial precipitation between the cathode or anode and the substrate region having the reaction gas inlet, it is not possible to carry out a stable process for the precipitation of the insulating film. 2. There is no fundamental solution to the droplet problem: the aggregate (droplet) is not completely reacted and produces metallic components in the membrane, hindering the increased roughness and stoichiometry of the membrane surface. 3. The heat load of the substrate is too large for the production of oxides in the high temperature phase, which may be insufficient to realize the low temperature process. 4. It has been impossible to produce a flat evaporated interlayer film for an insulating film by arc deposition.

Unlike sputtering, coating with a cathode arc is essentially a vapor deposition process. It is presumed that the non-atomic size portion is accompanied by droplets at the transition between the high-temperature cathode point and its peripheral portion. This conglomerate hits the substrate as if it could not be completely reacted in the droplets, resulting in a rough surface. This droplet avoidance or decomposition has not been successful so far and has not yet been successful for the reactive coating process. In this case, an oxide thin film, which tends to additionally increase the formation of droplets, is still formed on the arc cathode, for example, in an oxygen atmosphere.

<p num="0012"><patcit num="1"><text>European Patent No. 0666335</text></patcit><patcit num="2"><text>Federal Republic of Germany Patent No. 3,901,401</text></patcit><patcit num="3"><text>U.S. Pat. No. 5,103,766</text></patcit><patcit num="4"><text>International Publication No. 03018862 Pamphlet</text></patcit><patcit num="5"><text>Japanese Unexamined Patent Publication No. 2000-129445</text></patcit><patcit num="6"><text>JP-A-2002-254228</text></patcit></p>

<p num="0013"> An object of the present invention is to eliminate the above-mentioned drawbacks of the prior art. In particular, this task involves depositing materials and coatings with better properties using at least one arc deposition source so that better ionization of the reaction gas involved in the process increases reactivity in the process. It is economically precipitated. In the case of this reaction process, the size and frequency of droplets should be reduced essentially, especially in the case of the reactive process for forming an insulating film. Even better process control should be possible, such as controlling the deposition rate, improving the film quality, adjusting the film properties, improving the uniformity of the reaction and reducing the surface roughness of the precipitated film. These improvements are especially important in the production of gradient films and / or alloys. Process stability in the reaction process for the production of insulating films should generally be enhanced. In particular, an arc deposition process should be possible that allows economical precipitation of hard oxide material films, preferably aluminum oxide films and / or aluminum chromium oxide films that essentially have an α and / or γ structure.</p><p num="0014"> In addition, low temperature processes should be feasible, preferably below 700 ° C, and with high economic efficiency of the method. Moreover, the low temperature process must be able to be carried out with the high economic efficiency of the method. In addition, the cost for the equipment and especially the power supply for pulsed operation must be kept low. The above-mentioned problems occur individually or in combination depending on the required field of use.</p><p num="0015"> This problem is solved by a hard material film according to claim 1, which is manufactured by the arc-deposited PVD method according to the present invention. Dependent claims define other advantageous embodiments.</p>

<p num="0016"> This problem is solved by the present invention in which a hard material film is deposited on a work piece as an arc PVD functional film, and this film is essentially metal (Me) Al, Cr, Fe, Ni, Co, Zr, It consists of at least one of Mo and Y, and the functional film is formed as an electrically insulating oxide having a concentration of rare gas and / or halogen of less than 2%. However, the concentration of rare gas is less than 0.1%, especially 0.05% or less, or better zero, and / or the concentration of halogen is 0.5% or less, especially 0.1% or less or better zero. These gases are incorporated into the membrane in as little amount as possible, so that the arc deposition process exclusively uses pure reaction gases or pure reaction gas mixtures with rare gas components such as He, Ne, Ar or F.₂, Cl₂, Br₂, I₂Halogen gas or CF like₆Or performed without halogen-containing compounds such as analogs.</p><p num="0017"> Known CVD methods use halogen gases that deposit a film at an undesired high temperature of about 1100 ° C. Known sputtering processes are also operated under reaction process conditions with a high proportion of rare gases such as argon. The concentration of this type of gas in this membrane should be below the above value, or preferably zero. The pulsed arc deposition process according to the present invention makes it possible to do without this kind of process gas.</p><p num="0018"> The previous patent application specification with application number CH00518 / 05 essentially already points out a solution approach to this problem. A first solution has been described that is particularly well suited for fully reacted target surfaces and shows a clear reduction in droplet formation for DC driven arc deposition targets. In this application specification, it is proposed to superimpose a large current pulse on the DC feed of an arc-deposited source having a pulsed power source, as schematically shown in FIG. Further reductions in droplets and their size at a higher economy will be achieved by taking priority to CH00518 / 05 and taking action in accordance with subsequent patent application CH01289 / 05 representing developmental development. In this application specification, a vacuum processing apparatus for surface processing of a workpiece having at least one arc deposition source including a first electrode connected to a DC power source is provided, and one additional arc. A second electrode is provided, which is located separately from the deposition source, and both electrodes are connected to individual pulsed power supplies. Therefore, an additional discharge section with only one individual pulsed power supply is activated between both electrodes, which allows for particularly high ionization of the material involved in the very good controllability of the process. The second electrode can in this case be another arc deposition source, workpiece holder or workpiece itself, thereby driving the second electrode as a bias electrode in this case, or the second electrode being a low voltage arc. It can also be configured as a vapor deposition pit that forms the anode of the vapor deposition apparatus.</p><p num="0019"> A particularly preferred formation is that both electrodes are the cathodes of one arc deposition source each, and this arc deposition source is itself directly connected to a DC power source to maintain the holding current, and the arc or arc of both sources. Both cathodes are connected to individual pulsed power supplies so that the discharge is not extinguished during operation. Therefore, only one pulse power supply is required for this configuration, because this pulse power supply is directly connected between both electrodes of the arc deposition apparatus. In addition to high ionization and good controllability of the process, the high efficiency of the device is also tuned. Between these two electrodes and the pulse discharge gap additionally generated by it, a bipolar pulse consisting of negative and positive parts is electrically generated with respect to this discharge gap, whereby this supplied alternating current is generated. The full cycle time of the voltage can be utilized in the process. Virtually no unused pulse breaks occur and negative and positive pulses contribute to the process as a whole without interruption. The deposition rate can thereby be increased additionally, eliminating the need for additional expensive pulsed power supplies. This device, which has two arc deposition sources, is particularly suitable for film precipitation from metal targets using reactive gases. This arrangement also allows for the elimination of shielded rare gases such as argon altogether, and can be worked with pure reaction gases and, surprisingly, with pure oxygen. The vapor-deposited material also produces a non-conductive membrane with high quality, where the high achievable insulation of the reaction gas, such as oxygen, approaches the quality of the bulk material. The process proceeds very stably in this case, and surprisingly in this case further droplet formation is also dramatically reduced or almost completely avoided. However, the advantage is also that a second electrode, such as a bias electrode or a low voltage arc deposition crucible, is not achieved to the same extent as in the formation of an array with two arc deposition devices. Of another source as</p><p num="0020"> This application has obtained priority over both said prior applications CH00518 / 05 and 01289/05, which present a first solution approach to the problem of precipitation of an essentially electrically non-conductive oxide film. To do. The inventions introduced in this patent application are evolutionary developments relating to the implementation and application of the process. Both of these applications are thereby incorporated components of this application.</p>

<figref num="1">It is a schematic diagram of the arc vapor deposition coating apparatus corresponding to the prior art.</figref><figref num="2">It is an array according to the first invention having one DC fed arc deposition source during operation with superposed large current pulses.</figref><figref num="3">A second array, a dual pulse arc deposition array, having two DC powered arc deposition sources and a large current pulse power supply connected in between according to the present invention.</figref><figref num="4">It is sectional drawing of the film precipitated as a multilayer film according to this invention.</figref><figref num="5">FIG. 5 is an enlarged cross-sectional view of the membrane according to FIG.</figref>

Next, the present invention will be described in detail by way of illustration and illustration. FIG. 1 shows a vacuum processing apparatus showing a conventionally known apparatus for operating an arc-deposited source 5 provided with a DC power source 13. The device 1 is provided with a pump system 2 for generating the required vacuum in the chamber of the vacuum processing device 1. Pump system 2 pressure &lt;10^-1Allows the operation of coating equipment in mbar and is typical of reaction gases such as O₂, N₂, SiH₄, Guarantee operation using hydrocarbons, etc. The reaction gas flows into and corresponds to the chamber through the gas inlet. Inflow of additional reaction gas through yet another gas inlet, but or a rare gas such as argon, if this is required for the etching process or precipitation of non-reactive membranes, for example, gas alone and / Alternatively, it can be inflowed for use in a mixture. The workpiece holder 3 placed in the apparatus is utilized for accommodating and electrical contact of workpieces, which are not shown further here, usually made of metallic materials, and for precipitation of hard material films having this type of process. .. The bias power supply 4 is electrically connected to the workpiece holder 3 in order to excite the substrate voltage or the bias voltage in the workpiece. The bias power supply 4 can be a DC, AC or bipolar pulse or unipolar pulse-board power supply. Rare gas or reaction gas may be introduced via the process gas inlet 11 to set and control the process pressure and gas composition in the processing chamber.

The components of the arc-deposited source 5 are a target 5'with a cooling plate behind it, an arc finger 7 located in the peripheral region of the target surface, and an anode 6 surrounding the target. The switch 14 can be used to select between ungrounded operation of the anode 6 of the anode of the power supply 13 and operation with a defined zero or ground potential. A short contact with the cathode is made using the firing finger 7, for example, during the firing of the arc discharge of the arc deposition source 5, the cathode is subsequently pulled apart, which causes the arc to ignite. The firing finger 7 is for this purpose connected to the anode potential via, for example, a current limiting resistor.

The vacuum processing apparatus 1 may optionally be additionally equipped with an additional plasma source 9 if the process implementation requires it. In this case, the plasma source 9 is formed as a source for generating a low-voltage arc using a hot cathode. The hot cathode is formed as a filament arranged in, for example, a small ionization chamber, and a low voltage in which the working gas, for example, argon, reaches into the main chamber of the vacuum processing apparatus 1 by using the gas inlet 8 in the ionization chamber. It is put in for the generation of arc discharge. The anode 15 for the formation of the low voltage arc discharge is positioned correspondingly within the chamber of the vapor deposition process apparatus 1 and is a DC located between the cathode and the plasma source 9 and the anode 15 in a known manner. Driven by a power source. If necessary, a coil (10,10') placed around the vacuum processing device (1) for magnetic field focusing or magnetic guidance of the low voltage arc plasma, for example a Helmholzartige Anordnungen, is added. It may be prepared for.

Correspondingly, according to the present invention, the arc vapor deposition source 5 shown in FIG. 2 is additionally fed and driven by the pulse large current supply device 16'. The pulse power supply 16'is preferably superimposed directly on the DC power supply. Of course, both feeders must be operated electrically coupled to each other for their protection. This is a conventional method and can be done with a filter such as inductance, as is well known to electrical parties. Already according to the present invention, according to the present invention, a pure reaction gas or mixture of reaction gases such as oxides, nitrides, etc. without an undesired shield gas component such as argon in a PVD sputtering process or precursor halogen in a CVD process. It can be used to precipitate a film. In particular, it makes it possible to produce an electrically non-conductive, pure oxide in the desired crystalline form and precipitate as a film, which is very difficult and economical to obtain. This reactive pulse arc deposition method is thereby called the RPAE method.

In addition to the first arc-deposited source 5, which here has a target electrode 5', in another improved and preferred vacuum-processed arrangement according to the invention, this is shown in FIG. A second arc deposition source 20 having 2 target electrodes 20'is provided. Both arc-deposited sources 5, 20 are driven by one DC power source 13 and 13', respectively, so that the DC power source guarantees the maintenance of the arc discharge by the fundamental current. The DC power supplies 13 and 13'equivalent to today's technological level and can be realized at a suitable cost. Both electrodes 5'and 20'forming the cathodes of both arc deposition sources 5 and 20 have a high pulse current with a constant pulse shape and rising intensity on both electrodes 5'and 20' according to the present invention. It is connected to an individual pulse power supply 16 that can be delivered. In the array illustrated by FIG. 3, the anodes 6 of both arc deposition sources 5 and 20 are drawn into the ground potential of process equipment 1. This is also called the Dual Pulse Arc Deposition (DPAE) method.

It is possible to drive a spark discharge with or without grounding. In the absence of a preferred ground, the first DC power source 13 is connected to the cathode 5'of the first arc-deposited source 5 along with its negative electrode and to the anode of the second arc-deposited source 20 facing at its positive electrode. ing. The second arc-deposited source 20 is similarly driven, and the second power source 13'is connected to the positive electrode of the anode of the first arc-deposited source 5. This opposing operation of the anode of the arc deposition source results in good insulation of the material during the process. Ungrounded or floating or floating operation of arc deposition sources 5 and 20 can also be performed, but also without the use of opposing anode feeds. Further, a switch 14 can be provided as shown in FIG. 1 so that it can be selectively switched between ungrounded and grounded operations.

The power supply for this "dual pulsed mode" must be able to cover various impedance ranges and nevertheless be "robust" under voltage. That is, the power supply must provide a large current, but in that case it can nevertheless be sufficiently voltage stable. An example of such a supply was filed in parallel on the same date as said Patent Application No. CH1289 / 05 with No. CH518 / 05.

The first and advantageous field of use of the present invention is, for example, the field of use of cathode arc deposition using two pulsed arc deposition sources (5,20) shown in FIG. For this use, the impedance at intervals is about 0.01Ω ~ 1Ω. It should be noted here that the impedances of the sources, "dually pulsed" between these sources, usually vary. It may be because they are made of different materials or alloys, the magnetic fields of the source are different, or the removal of the material of the source is at different stages. This "dual pulsed mode" will now allow equalization of pulse width adjustments so that the two sources consume the same current. As a result, various voltages are brought to the source. Of course, the power supply may also be asymmetrically loaded with respect to current if it is deemed desirable for the implementation of the process, which is true, for example, for functionally graded membranes of various materials. The voltage stability of the supply becomes more difficult to achieve as the impedance of each plasma decreases. Therefore, the switchability or followability of the supply to various output impedances is realized when the entire region of the output is to be used, that is, for example, in the range 500V / 100A to 50V / 1000A or in parallel application number CH518 / 05. It is a particular advantage as it has been.

The advantages of such a dual pulsed cathode device, in particular consisting of two arc deposition sources, can be summarized as follows.

1. Increased electron emission in steeply sloping pulses results in greater current (also substrate current) and increased ionization of evaporated materials and reaction gases.

2. The increased electron density in the case of insulating film formation also contributes to the faster discharge of the substrate surface, i.e., a relatively small reload time (Umladezeiten) (or bias voltage pulse break only) in the substrate is generated. Sufficient to discharge the insulating film.

3. Bipolar operation between two cathodic arc deposition sources allows for a pulse break ratio (duty cycle) of nearly 100%, whereas pulses from only one source inevitably always require pauses and are therefore less efficient. Absent.

4. The dual pulsed operation of the two cathode arc sources facing each other immerses the substrate region in dense plasma, increasing the reactivity of the reaction gas in this region as well. The increase in substrate current is obvious.

5. In the case of reaction processes under oxygen atmosphere, increased electron emission values can still be achieved in pulsed operation, and melting of the spark region as is the case with conventional deposition from metal targets. It can be sufficiently avoided. Working in a pure oxidation reaction mode without any other external or shielded gas is effortlessly possible here.

In order to be able to achieve the above-mentioned advantageous process characteristics in the various possible embodiments described above of the present invention, the pulse power supplies 16 and 16'must satisfy various conditions. In the case of bipolar pulse representation, the process can be operated at frequencies in the range of 10 Hz to 500 kHz. Due to the ionization properties, the rising edge of the pulse that can be stopped here is important. The amount of rising edge U2 / (t2-t1), U1 (t6-t5) and the amount of falling edge U2 / (t4-t3) and U1 (t8-t7) are in the range of 0.02V / ns ~ 2V / ns. It should have a steepness in, and it should have at least in no-load operation, i.e. no load, but preferably in the case of load. Of course, the rise degree is affected during operation depending on the corresponding load or the magnitude of the applied impedance or the corresponding height of adjustment. The pulse width in the bipolar display is favorably 1 μs for t4 ~ t1 and t8 ~ t5, and the dormant t5 ~ t4 and t9 ~ t8 can be advantageously essentially zero, but certain prerequisites. It can be 0 μs below. If the pulse break is&gt; 0, this operation is said to have a gap, and for example a variable time shift of the pulse gap width can adjust the proper input of energy to the plasma and its stability. .. It is especially advantageous when the pulse power supply is designed so that the pulse mode can be up to 500A at 1000V, in which case the pulse intermittent ratio (duty cycle) is considered correspondingly to the designed possible supply output. Or it must be adapted. It is noted that in addition to the rise in pulse voltage, preferably the pulsed power supply (16) can overcome the current increase to 500 A in at least 1 μs.

By the operation introduced here for arc deposition sources with DC feed and superposed high current pulse feed (RPAE, DPAE), the corresponding metal compounds are processed from one or more metal targets using a reactive gas atmosphere 30 It is possible to deposit on top. This is particularly suitable for the formation of pure oxide films, as this method does not require a rare gas, usually an additional shielding gas such as argon. Thereby, the plasma discharge of the arc deposition apparatus 5, 20 can be carried out, for example, and preferably in a pure oxygen atmosphere at a desired operating pressure without unstable discharge, or too strong droplet formation or poor film. It can be prevented from providing useless results such as traits. Moreover, it is not necessary to use a halogen compound as in the case of the CVD method. This is the first time a low process temperature, preferably below 500 ° C, and the result is nevertheless heat resistant, preferably above 800 ° C, and chemically very much, for example high oxidation resistance. It makes it possible to economically produce a wear-resistant hard oxide material film having high quality and resistance. Diffusion of oxygen due to oxidation associated with it to achieve a more stable membrane system should be avoided as much as possible in lower membrane systems and / or workpieces.

Here, the oxide film can be easily produced as a reaction gas from periodic subgroups IV, V, VI transition metals and Al, Si, Fe, Co, Ni, Y in pure oxygen, in which case Al, Cr, Mo, Zr and Fe, Co, Ni, Y are preferred. The functional membrane 32 does not contain any halogens such as rare gases and / or Cl as oxides of one or more of the metals, but at least less than 0.1% or better less than 0.05% rare gases and 0.5. Contains less than% or better less than 0.1% halogen to achieve the desired film quality.

This type of functional film 32 or multilayer system 33 (multilayer) should have a thickness in the range of 0.5-12 μm, preferably 1.0-5.0 μm, especially as a hard material film. It can be deposited directly on the workpiece 30 as a functional film, which is a cutting tool such as a tool, mechanical member, preferably a indexing tool. It contains at least one other membrane or membrane system between this membrane and the work piece 30, particularly an adherent membrane, and preferably one of the metals of the periodic subtribes IVa, Va and VIa. And / or can be precipitated for the formation of an interlayer 31 containing Al or SI or a mixture thereof. Good adhesion properties are achieved with compounds of this metal, N, C, O, B or mixtures thereof, and it is advantageous for the compounds to have N. The film thickness of the interlayer film 31 should be in the range of 0.05 to 5 μm, preferably 0.1 to 0.5 μm. At least one of the functional membrane 32 and / or the interlayer 31 can be advantageously formed as a stretched membrane 34, which results in a good transition of the properties of each membrane. This stretching can extend from metals through nitrides to nitrogen oxides and even to pure oxides. That is, a stretched region 34 is formed, in which the material of the mutual butt membrane or the work piece material is mixed with each other if there is no interlayer film.

Another membrane or membrane system 35 can be deposited on the functional membrane 32 as a coating layer, if required. The coating layer 35 can be precipitated as an additional friction reducing film to further improve the tribological behavior of the coated workpiece 30.

Depending on each requirement, one or more of said membranes or membrane systems, where this is the region where the flanking membrane 34 is formed, or where any form of concentration gradient is generated within the individual membranes. Can form a film. In the present invention, this can be easily done by controlling and blowing the reaction gas into the vapor deposition process apparatus 1 to adjust the type of gas required for that purpose and the amount of gas in the reactive arc plasma process, respectively. is there.

Here, without difficulty, an aluminum oxide film (Al) having a desired hard material property as a functional film 32 and a composition of stoichiometry in essence.₂O₃) Membranes can be manufactured. A particularly preferred hard material film as the functional film 32 is essentially the formula (Al_xMe_1-x)_yO_z(In the formula, Me is preferably one of the metals Cr, Fe, Ni, Co, Zr, Mo, Y and can be adjusted individually or in admixture according to the desired proportions x, y and z of the participating substances, respectively. It consists of an aluminum metal (Me) metal oxide film. More particularly preferably, it results in the equation (Al_xCr_1-x)_yO_zOr (AlCr)_yO_zForm (Al_xMe_1-x)_yO_zChrome as the metal Me in the metal mixed oxide of. In this case, the proportion 1-x of metallic chromium in the film should have 5-80At%, preferably 10-60At%. As a hard material functional film 32, metal nitrides, especially aluminum chromium nitrides (AlCr)_yN_zOr if necessary (AlTi)_yN_zIs very suitable.

Depending on the defined possibility of carrying out the process, it is also possible here that aluminum oxide and chromium oxide can also achieve particularly desired α and / or γ structures.

For the first time for the above-mentioned easy tweakability of membrane conditions having a composition of the reaction gas via control of the supply of the reaction gas, and for the implementation of a stable process, the multilayer system (multilayer) 33. It is also possible to produce the above in any number of layers, in any composition, and with further stretchability. In this case, multiple layers can be produced from a variety of materials, or, often advantageous, in alternating equal materials as a sandwich form. In the case of the rigid material functional membrane 32, a membrane system having a repeating membrane forward 33 in which the material composition changes periodically is advantageous. Especially Me₁From Me₂To oxides and / or Me₁From Nitride to Me₁To oxides and / or Me₁From Nitride to Me₂The structure to the oxide provides excellent results with respect to the useful life and less crack formation of the functional membrane or this membrane system. An example of the functional film 32 as the multilayer film 33 is shown in FIG. 4, and an enlarged cross-sectional view is shown in FIG. Alternating aluminum nitride chromium (AlCr)_xN_yThe preferred material pair is aluminum oxide chromium (AlCr) according to the method according to the present invention, preferably stoichiometric material composition._xO_yIndicates that it was manufactured by. The membrane package comprises a membrane pair having alternating materials as described above in Example 42. The total film thickness of this functional film 32 is about 4.1 μm for the multilayer system 33, so that the thickness of the film pair, that is, the two layers are 98 nm. Other preferred material pairs are, by the method according to the invention, preferably stoichiometric material compositions, alternating with aluminum nitride zirconium (AlZr)._xN_yIs aluminum oxide zirconium (AlZr)_xO_yManufactured in. It is advantageous when the multilayer system 33 has at least 20 layers, preferably 500 layers, with respect to the hard material layer as the functional film 32. In this case, the thickness per layer should be in the range 0.01-0.5 μm, preferably in the range 0.2-0.1 μm. In the region of the individually adjacent layers of the membrane, the stretched portion 34 is also clearly considered for the good behavior of the transition portion. In the example shown in FIG. 4, as an example, the coating layer 35 is also deposited as a friction reducing film via the functional films 32 and 33. The coating layer is made of titanium nitride and has a thickness of about 0.83 μm. As an example, one intermediate film 31 is additionally arranged under the functional film as an adhesive film, and this intermediate film is about 1.31 μm thick, and the Al-Cr-N intermediate film is processed by RPAE 30. Precipitated upwards.

The coatings presented here, whether single or multi-membrane systems, preferably do not exceed 2 μm._zValue and / or R not less than 0.2 μm_aShould have a value. Each of these values is measured directly on the surface before possible post-treatment such as direct brushing, sandblasting, grinding, etc. Thereby this value indicates a purely process-constrained surface roughness. R_aUnder the above, the average roughness according to DIN 4768 is understood. This is the arithmetic mean value of the total deviation of the roughness characteristics from the average line inside the entire measurement section lm. R_zUnder the above, the average roughness depth according to DIN 4768 is understood. This is 5 consecutive individual measurement intervals in roughness characteristics l_eIt is an average value from the individual roughness of. R_zDepends on the distance between the deepest valley and the highest peak. The mean value formation alleviates the influence of individual peaks (valleys), and the mean width of the band containing the R characteristic is calculated.

The coatings introduced according to the present invention are particularly suitable for workpieces such as cutting tools, forming tools, injection molding dies or punching tools, but perfectly particularly particularly for indexing tools.

Hereinafter, the typical process of substrate processing is described in use of the present invention, a reactive pulsed arc vapor deposition coating process. In addition to the original coating process in which the present invention is realized, other process steps related to pretreatment and posttreatment of the work piece will also be described in detail. All these steps allow a wide range of deformations, some can be abolished, shortened or stretched or otherwise combined under special conditions. In the first step, the work piece is usually subjected to a wet chemical cleaning, which is performed differently depending on the material and prior history. Example 1: Al-Cr-O film 32 by RPAE (Reactive Pulse Arc Deposition) for coating workpiece 30, such as cutting tools, preferably indexing tools, (and AL-Cr-N / Al-Cr- Description of typical process processes for the production of O-multilayer 33) and Al-Cr-N interlayers 31.

1. Pretreatment (cleaning, etc.) of processed products (30) (boards) as known to those skilled in the art 2. Insertion of the substrate into the holder provided for that purpose and incorporation into the coating system 3. As is known to those skilled in the art, pumping of the coating chamber at a pressure of approximately 10-4 mbar by the pumping system (prepuming / Diffusion pump, pre-pumping / turbo molecular pump, final pressure about 10-7mbar can be achieved) 4. Initiation of substrate pretreatment in vacuum with heating steps in argon hydrogen plasma or other known plasma treatment. This pretreatment can be carried out with the following parameters without limitation. A discharge current of about 100 A, a low voltage arc discharge plasma up to 200 A, up to 400 A, preferably the substrate is connected as an anode for this low voltage arc discharge. Argon flow 50sccm Hydrogen flow 300sccm Substrate temperature 500 ° C (partially by plasma heating, partly by radiant heating) Process time 45 minutes Preferably, during this step, the substrate 30 and ground or the substrate is between other reference potentials that can be applied as direct current (preferably positive) or direct current pulse (unipolar, bipolar) or MF (intermediate frequency) or RF (radio frequency). Is applied to the supply section of.

5. Etching starts as the next process step. Therefore, a low voltage arc is operated between the filament and the auxiliary anode. A DC, pulsed DC, MF or RF power supply is connected between the board and ground, and the board is preferably applied at a negative voltage. Positive voltages are also applied to the substrate in the pulsed power supply and the MF and RF power supplies. This power supply can operate unipolar or bipolar. Typical but non-exclusive process parameters during this step: Argon flow 60sccm Discharge current low voltage arc 150A Substrate temperature 500 ° C (partly by plasma heating, partly by radiant heating) Process time 30 minutes A large power source treated or pulsed with a hot conductive auxiliary anode is connected between the auxiliary electrode and ground to ensure the stability of the low voltage arc discharge during the manufacture of the insulating film. Has been done.

6. Start of coating with interlayer film 31 (about 15 minutes) Spark vapor deposition (source current 140A, Ar80sccm, N₂ CrN interlayer film 300 nm with bias from 1200 sccm, -80V or -100V to -60V or 40V. Coating can be done with or without a low voltage arc.

7. Transition to functional membrane 32 (about 5 minutes) In the transition to the original functional membrane, the arc source is additionally superimposed on the unipolar DC pulse of the second power source that can operate at 50kHz (Fig. 2). In addition, the Al target is driven in the same way to produce AlCr as a film. For example, at 10 μs, a pulse / 10 μs pause is activated, which produces a current of up to 150 A. An influx of 200 sccm of oxygen is then carried out.

8. Return of AlCrN coating After the oxygen gas flow stabilizes, the AlCrN coating is decelerated. Therefore, the N2 gas flow is reduced. This lamp runs for about 10 minutes. The Ar flow is then driven to zero (unless working with a low voltage arc).

9. Coating with functional film 32 Coating of the substrate with the original functional membrane is carried out with pure reaction gas (oxygen in this case). Most important process parameters: Oxygen flow 400sccm Substrate temperature 500 ° C DC source current 60A A 150A pulsed DC current (unipolar) with a pulse frequency of 50kHz and a pulse characteristic of 10μs pulse / 10μs pause is superimposed on the DC source current. Process pressure in the coating chamber 9 × 10^-3mbar. The bias on the board is returned to -40V. Since aluminum oxide is an insulating film, a bias supply driven as a DC pulse or MF (50kHz-350kHz) is used. The coating can be performed at the same time as the low voltage arc. In this case, higher reactivity can be obtained. Furthermore, the simultaneous use of low voltage arc has the advantage that the DC component can be reduced at the source during coating.

This can make the arc current higher and even lower. The coating process thus guided is stable over several hours. Targets 5 and 5'are covered with a thin flat oxide film. However, despite the fact that the target surface is changed by oxygen, no insulating islands are generated, which also appears at the high burning voltage. The target surface is essentially flatter. The arc travels coarser and is split into multiple smaller arcs. The number of droplets is essentially reduced.

The process is a basic preferred version as this process reduces the requirements for pulsed power supplies. DC feeding provides the minimum or holding current for the arc, and pulse maximum power supplies 16, 16'are used to avoid droplets, making the process more stable.

The possibility of generating a multilayer system 33, that is, a multilayer system 33 for the above membrane train, is that the oxygen flow during membrane precipitation is reduced or completely blocked here, while the nitrogen flow is connected. is there. This can be done with a membrane of oxygen-nitrogen concentration that is exclusive or mixed, both cyclically and aperiodically. By this method, the multilayer 33 is manufactured as enlarged in FIGS. 4 and 5 as shown in the cross-sectional view as an example. In many cases, this functional membrane 32 closes the coating outwards, with no other membrane on top of it.

Abrasion properties can be "getopted" by one or more coating layers 35 for each application and as required. An example of an AlCrN / AlCrO multilayer that already has the TiN topcoat described above is also shown in FIG. At least one coating layer 35 can be, for example, a friction reduction film in this case, and then a hard material film 32 or a functional or multilayer film is utilized as a protective film for the friction reduction film 35.

The preferred process deformation is exactly that the target exhibits the first poisoning phenomenon (voltage rise, usually a few minutes), especially if there is a desire to produce a multilayer functional film 33 or a multilayer interlayer film with a thin oxide-containing film thickness. It can also be carried out by the operation of the oxide-forming target under oxygen flow until (later) and then again switched to, for example, a nitrogen stream. This process transformation is particularly simple and can be achieved by existing conventional techniques (Figure 1), namely target pulse operation. However, this does not allow free alignment of film thickness to each requirement.

Aspects of the above example during dual pulse operation with two or more arc deposition sources provide additional advantages in terms of process implementation and economy. Example 2: Coating of a workpiece 30 such as a cutting tool, preferably a indexing tool, with an Al-Cr-O hard material film system 32 and a Cr-N interlayer 31 by DPAE (Dual Pulse Arc Deposition Equipment).

Includes steps 1 through 5 according to Example 1. 6. Start of coating with interlayer film (about 15 minutes) -Spark deposition (target material AlCr (50%, 50%), source current 180A, N, with bipolar bias of -180V (36μs minus, 4μs plus)₂ AlCrN interlayer film 300 nm by 800 sccm. Coating can be performed with and without a low voltage arc. To this point, the method follows this conventional technique, as shown in FIG. 1 as an example of the prior art.

7. Transition to functional membrane 32 (about 5 minutes) In the transition to the original functional membrane 32, nitrogen is tilted down from 800 sccm to about 600 sccm, followed by an oxygen stream of 400 sccm. Here the nitrogen flow is blocked.

8. Coating with functional film 32 Here, as shown in FIG. 3, the bipolar pulse maximum power supply 16 is operated between both arc-deposited cathodes 5 and 20. The process operates with a temporally positive or negative mean of a current of about 50 A. The pulse time is 10 μs each at a voltage of 160 V in between for the positive and negative voltage regions, each with a 10 μs pause. The peak value of the current from the bipolar pulse power supply 16 depends on each pulse shape. The difference from the DC current due to each arc-deposited cathode 5, 20 and peak value of the bipolar pulse current is less than the holding current of the so-called arc-deposited cathodes 5, 20 because the arc (spark) is otherwise extinguished. Must not be. The bias is tilted from -180V to -60V during the first 10 minutes of coating. Typical coating rates for the doubly rotating workpiece 30 are 3 μm / h and 6 μm / h. That is, the coating of the work piece 30 having the original functional membrane 32 is carried out with a pure reaction gas (oxygen in this example). The most important process parameters are summarized again. Oxygen flow 400sccm Work piece temperature 500 ° C DC source current 180A for both Al and Cr sources The bipolar pulsed direct current between both cathodes has a frequency of 25 kHz. Process pressure about 9 × 10^-3mbar As mentioned above, the coating can be performed at the same time as the operation of the low voltage arc. In this case a further increase in reactivity is achieved, especially in the vicinity of the work piece. Furthermore, the simultaneous use of low voltage arcs during coating has the advantage that the DC component can be reduced at the source. With higher arc current, this can be further reduced.

The coating process thus guided is stable over several hours. Arc vapor deposition equipment 5, 20 Targets 5', 20'are covered with a thin, flat oxide film. This is also a prerequisite for a desirable, widespread, droplet-free and stable process. This coating is embodied in the voltage rise at the target.

The work piece is coated with various coatings and is subjected to substantial comparative tests under the same conditions. Rotation test conditions: A known TiAlN film and a known aluminium oxide film precipitated by CVD were considered as the criteria for this test. The film thickness of 4 μm was investigated for all test membranes. Stainless steel (1.1192) was used as the test material. We selected 1, 2 and 4 minutes as the rotation cycle, respectively. This cutting speed is 350m / min, feed is 0.3mm / rev, and bite depth is 2mm. This condition was chosen so that a short test time could be achieved at high temperatures at the cutting edge of the workpiece. The wear on the free and cut surfaces and the surface roughness of the machined steel were investigated, and the duration until a certain increased roughness occurred was calculated. This durability time was calculated as a quantitative standard for wear. result: a) CVD film α-aluminum oxide (conventional technology) Film thickness d = 4 μm. The tool withstood the test for 4 minutes. However, after testing with SEM, the membrane material was no longer on the cutting surface.

b) TiAlN membrane (conventional technology), d = 4 μm This film already showed first fracture after less than 2 minutes and left a rough surface on the work piece. invention: c) AlCrN interlayer, d = 0.4 μm AlCrN / AlCrO multilayer, d = 3.6 μm TiN top coat, d = 0.8 μm Endurance time 4 minutes d) AlCrN interlayer, d = 0.4 μm AlCrN / AlCrO multilayer, d = 3.6 μm 3 minutes 40 seconds e) AlCrN interlayer, d = 0.3 μm AlCrO single layer, d = 2.9 μm TiN top coat, d = 0.9 μm 4 minutes f) AlCrN interlayer, d = 0.35 μm AlCrO single layer, d = 3.5 μm 3 minutes 20 seconds g) ZrN interlayer film, d = 0.3 μm ZrN / AlCrO multilayer, d = 3.8 μm ZrN top coat, d = 0.5 μm 3 minutes 10 seconds h) ZrN interlayer film, d = 0.2 μm ZrO / AlCrO multilayer, d = 6.4 μm ZrN top coat, d = 0.8 μm 4 minutes i) AlCrN interlayer, d = 0.5 μm AlCrO / α Alumina Multilayer, d = 8.2 μm 4 minutes k) (Ti, AlCrN) interlayer film, d = 0.4 μm AlCrO / TiAlCrN multilayer, d = 4.5 μm 3 minutes 50 seconds Multilayers containing films or oxides of the indicated material show less wear at apparently higher cutting speeds. According to prior art, conductive films (TiAlN) are clearly inferior to oxides according to the present invention in terms of wear at high cutting speeds. (AlCr)_yO_zAnd (AlZr)_yO_zThe system according to the present invention consisting of shows less wear similar to known CVD films made of alpha aluminum oxide, but without those drawbacks of high temperature loading or corrosive chemical loading of the workpiece during the coating process. .. In addition, the implementation of the process is essentially easier, for example gas switching or controlled changes in gas composition (eg O).₂From N₂It can be carried out by switching the target or by controlling the components of the target feed to the other, while in the CVD process intermediate cleaning and temperature levels for the individual membranes of the multi-layer membrane system. Conformity is required.

1 Vacuum processing equipment, 2 Pump system, 3 holders, 4 Bias power supply, 5 Arc deposition source, 5'Target, 6 Anode, 7 Fire finger, 8 Gas, 9 Plasma source, 10, 10'Coil, 11 Process gas inlet , 13 DC power supply, 14 switches, 15 anodes, 16, 16'pulse power supply, 20 arc deposition source, 20'target.