DE102009015478A1 - Producing hard material layers by magnetron sputtering, comprises carrying out a substrate cleaning and then a substrate pre-treatment, in which a coating material is deposited on a substrate with a magnetron in pure inert gas atmosphere - Google Patents

Abstract

The method comprises carrying out a substrate pre-treatment, in which a coating material (2) is deposited on the substrate (3) with a magnetron in pure inert gas atmosphere, where the substrate is at a negative bias, which is high, so that the coating material is partially implanted into the substrate. The negative bias is controlled during the substrate pre-treatment, so that a balance between the deposited and re-etched material is adjusted. The negative bias of the substrate is adjusted to -800 V to -1200 V during the substrate pre-treatment. The method comprises carrying out a substrate pre-treatment, in which a coating material (2) is deposited on the substrate (3) with a magnetron in pure inert gas atmosphere, where the substrate is at a negative bias, which is high, so that the coating material is partially implanted into the substrate. The negative bias is controlled during the substrate pre-treatment, so that a balance between the deposited and re-etched material is adjusted. The negative bias of the substrate is adjusted to -800 V to -1200 V during the substrate pre-treatment. Before the substrate pre-treatment, a substrate cleaning is carried out, in which the coating material is sputtered on the substrate with the magnetron in pure inert gas atmosphere, where the substrate is at negative bias, which is high, so that a removal of the substrate material adjusts itself in spite of coating. The negative bias of the substrate is adjusted to -1500 V during the substrate cleaning, and is reduced to an amount of less than 400V at the end of the substrate cleaning. The negative bias of the substrate is reduced to -50 V to -200 V for a layer construction on the substrate. The bias reduction takes place continuously or in steps of 100 V up to 200 V. The substrate pre-treatment takes place with chromium, titanium, titanium aluminide, zirconium, vanadium, niobium, tantalum, tungsten or tungsten carbide. For the substrate pre-treatment and the layer construction, a combination of the different coating materials is used. The reactive hard material layer is deposited on the substrate for the layer construction. For the layer construction on the substrate, carbon from a highly-pure graphite target is deposited in a weak reactive atmosphere containing argon and ethyne or argon and nitrogen, where a super-hard ta-carbon (C)-layer, tantalum-C:hydrogen (H) layer or a-C:H layer grows up on the substrate. The gas flow of the reactive gases is adjusted to 1-20% of the argon flow. For the layer construction on the substrate, the deposition of the carbon takes place in the atmosphere with a mixture of argon and neon and in pure neon atmosphere.

Description

The The present invention relates to a process for the preparation of Hard material layers by means of magnetron sputtering.

A method of this type is from the document DE 10 2006 020 004 A1 known.

at the deposition of hard coatings on substrates results due to high layer stresses of the deposited hard layers often the problem of a lack of adhesion.

It is therefore the object of the present invention, a method the species mentioned to seduce, in which Hard material layers with sufficient adhesion to substrates can be separated.

The Task is by a process for the production of hard coatings solved by magnetron sputtering, wherein in the process a substrate pretreatment is performed, wherein at least a magnetron coating material in pure noble gas atmosphere is deposited on at least one substrate on a negative Preload is so high that the coating material at least partially implanted in the substrate.

at the method according to the invention occupy first Particles of the coating material the surface of the Substrate. By the invention according to the substrates present very high negative bias voltage meet rare gas ions with high energy on the substrate surface and act on the one hand back sputtering, so many of the already on the surface deposited particles of the coating material sputtered back into the atmosphere of the deposition chamber become. On the other hand, due to the high energy of the incident noble gas ions also some of the resting on the substrate surface Particles of the coating material in the surface of the Substrate struck, d. H. implanted. The by the partial Implantation modified surface forms a special good basis for a subsequent growth of a hard material layer, so that by the inventive method Adhesive strength of a modified by the implantation Surface deposited hard material layer increases can be.

Preferably becomes the negative during this substrate pretreatment Bias of at least one substrate controlled so that a balance between deposited and etched material is set. In this way, during substrate pretreatment no new layer built on the substrate, so through the Substrate pretreatment a pure modified, implanted surface of the substrate can be made available.

It has proved to be particularly advantageous when the negative bias of the at least one substrate in the substrate pretreatment between about -800 V and about -1200 V is set.

Corresponding a preferred embodiment of the present invention Invention, a substrate cleaning is carried out before the substrate pretreatment, in which with the at least one magnetron coating material in pure noble gas atmosphere on the at least one substrate sputtered, which is on a negative bias, the is so high that, despite coating, a net removal of the substrate material established. By removing the substrate material can be a clean Surface before the actual coating, d. H. one actual cleaning effect can be achieved, so a better grip of the subsequently deposited layer allows can be.

Preferably the negative bias in substrate cleaning will be up to about -1500 V set.

It is particularly favorable when the negative bias of the at least one substrate at the end of the substrate cleaning on a Amount of less than 400 V is reduced. For negative biases of an amount less than 400 V leads the least Magnetron supplied power to the fact that no substrate removal more takes place, but instead a layer buildup on the Substrate takes place.

For example can the negative bias of the at least one substrate for a layer structure on the at least one substrate to about -50 V be reduced to about -200V. With such a negative Pretension of the substrate is the substrate removal and implantation of coating material in the surface of the substrate towards zero and there is an effective layer buildup on the substrate instead of.

For example In this case, the voltage reduction can be continuous or in steps from about 100V to about 200V.

It has proven to be particularly advantageous when the substrate pretreatment with Cr, Ti, TiAl, Zr, V, Nb, Ta, W or WC.

Furthermore, it is advantageous if, for the actual layer structure on the at least one sub Preferably, at least one hard material layer of CrN, CrCN, TiN, TiCN, TiAlN, TiAlCN, TiAlON, ZrN, ZrCN, VN or VCN, or non-reactive corrosion-resistant and biocompatible Ti, Nb, Ta or W is deposited.

The possible range of applications for the inventive method can be increased when used for substrate treatment and for the actual Layer construction a combination of the listed different Coating materials is used.

According to one preferred embodiment of the present invention is used for substrate pretreatment Cr, Ti, W or WC used and for the actual layer structure on the substrate carbon of at least one high purity graphite target deposited.

In this process variant, it is particularly advantageous if the carbon in a weakly reactive atmosphere of Ar + C ₂ H ₂ or Ar + N _{2 is} deposited and on the at least one substrate, a superhard ta-C, Ta-C: H or aC: H layer grows up.

in this connection it is particularly advantageous if the gas flow of the reactive gas is set in a range of about 1% to about 20% of the Ar flow.

Further it is favorable in this process variant, if for a layer structure on the at least one substrate the deposition of the carbon in an atmosphere with a mixture from Ar and Ne or in pure Ne atmosphere takes place.

in the The following is the method according to the invention explained in more detail with reference to an embodiment in which

1 schematically shows the processes taking place on a substrate surface during a substrate cleaning which can optionally be used according to the invention;

2 schematically shows the processes taking place on a substrate surface during the substrate pretreatment proposed according to the invention; and

3 schematically shows the processes taking place on a cleaned and pretreated substrate surface during the actual layer construction according to the present invention.

1 schematically shows an arrangement in a vacuum chamber 10 a PVD deposition device with at least one magnetron 1 to which a target 11 with a coating material 2 assigned. Further, in the vacuum chamber 10 at least one substrate to be coated 3 with a substrate surface 4 intended. The substrate 3 is either directly or indirectly with a power supply 5 coupled, through which the substrate 3 can be placed on a very negative bias.

Furthermore, the vacuum chamber has 10 at least one gas supply 6 for the supply of a noble gas or noble gas mixture. In the example of 1 is used as noble gas argon. In addition, at the vacuum chamber 10 at least one gas outlet 7 with a vacuum pump and a throttle valve 9 intended.

In the in 1 illustrated method step, according to an embodiment of the method according to the invention, a substrate cleaning of the surface 4 of the substrate 3 carried out. Here, the coating material is before the actual coating 2 in a noble gas atmosphere on the at least one substrate 3 sputtered, with the substrate 3 is at a very high negative bias, which is so high that, despite the deposition of the coating material 2 net, a removal of the substrate material of the substrate 3 on its surface 4 results. That is, by the high negative bias the particles hit 21 of the coating material 2 with such high energy on the surface 4 of the substrate 3 on that particle 31 of the substrate 3 from its surface 4 be knocked out. This can make a clean surface 4 of the substrate 3 , that is, an actual cleaning effect, to be set.

In the example of 1 is the negative bias of the substrate 3 up to -1500 V.

At the end of in 1 schematically shown substrate cleaning of the substrate 3 For example, the amount of negative bias can be reduced to less than 400V, leaving the substrate 3 is coated and net no substrate removal takes place.

2 schematically shows the processes occurring in the substrate pretreatment proposed according to the invention on the basis of FIGS 1 already described above arrangement.

In the process step of 2 is attached to the at least one substrate 3 placed such a high negative bias, that by the magnetron 1 on the substrate 3 deposited coating material 2 at least partially into the substrate 3 is implanted. This is done as follows: The substrate 3 is caused by the voltage source 5 placed on a negative bias between about -800 volts and about -1200 volts. Through the magnetron 1 becomes the coating material 2 on the surface 4 of the substrate 3 deposited, so first particles 21 of the coating material 2 the surface 4 of the substrate 3 occupy. Noble gas ions 61 hit by the high negative bias of the substrate 3 with high energy on the surface 4 of the substrate 3 and thus back sputtering, so that already deposited particles 22 of the coating material 2 again from the surface 4 be thrown back into the atmosphere or the plasma.

Others, on the substrate surface 4 separated particles 23 of the coating material 2 are due to the very high energy on the substrate surface 4 impinging noble gas ions 61 in the surface 4 literally hit, that is in the surface 4 of the substrate 3 implanted.

At the in 2 The method step shown is the negative bias of the substrate 3 preferably adjusted so that about the same amount of coating material 2 etched back as it is deposited so that essentially no new layer on the substrate surface 4 is generated, but the in 2 shown substrate pretreatment is used to the substrate surface 4 of the substrate 3 by the implantation of the coating material 2 to modify.

Through the implant surface modified by implantation 4 can be deposited subsequently on this substrate surface, for example, a hard material layer, which, due to the surface modification of the substrate 3 , has a particularly high adhesive strength.

For example, for the in 2 schematically shown substrate pretreatment materials such as Cr, Ti, TiAl, Zr, V, Nb, Ta, W or WC can be used.

3 schematically shows an actual layer structure on the substrate 3 according to the in 1 and 2 illustrated arrangements. Here is the substrate 3 placed a negative bias, which is between about -50 V and about -200 V. For this purpose, the negative bias starting from the in 2 illustrated method step is reduced either continuously or in steps of about 100 V to about 200 V to said negative bias value.

For the actual layer structure according to the in 3 1, at least one hard material layer of materials such as CrN, CrCN, TiN, TiCN, TiAlN, TiAlCN, TiAlON, ZrN, ZrCN, VN or VCN or non-reactive corrosion-resistant and biocompatible Ti, Nb, Ta or W can be deposited by reaction.

For substrate pretreatment according to 2 and for the layer structure after 3 For example, a combination of the listed different coating materials may also be used.

It is also possible, according to an embodiment of the present invention, for the layer structure on the substrate 3 Carbon is deposited by at least one high purity graphite target. It is advisable to deposit the carbon in a weakly reactive atmosphere of Ar + C ₂ H ₂ or Ar + N ₂ and then on the at least one substrate 3 to grow a superhard ta-C, Ta-C: H or aC: H layer. Preferably, in this case, the gas flow of the reactive gas can be adjusted in a range from about 1% to about 20% of the Ar flow. For the actual layer structure on the at least one substrate 3 it is particularly advantageous if the deposition of the carbon from the at least one graphite target in an atmosphere with a mixture of Ar and Ne or in pure Ne atmosphere takes place.

QUOTES INCLUDE IN THE DESCRIPTION

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Cited patent literature

• - DE 102006020004 A1 [0002]

Claims (15)

Process for the production of hard coatings by means of magnetron sputtering, characterized in that in the process a substrate pretreatment is carried out, in which with at least one magnetron ( 1 ) Coating material ( 2 ) in a pure noble gas atmosphere on at least one substrate ( 3 ) is deposited, which is at a negative bias that is so high that the coating material ( 2 ) at least partially into the substrate ( 3 ) is implanted. Method according to claim 1, characterized in that That is, the negative bias in substrate pretreatment is controlled will that balance between deposited and re-etched Material is set. Method according to claim 1 or 2, characterized in that the negative bias of the at least one substrate ( 3 ) is set at substrate pretreatment between about -800V and about -1200V. Method according to one of the preceding claims, characterized in that before the substrate pretreatment, a substrate cleaning is carried out, in which with the at least one Magnatron ( 1 ) Coating material ( 2 ) in a pure noble gas atmosphere on the at least one substrate ( 3 ) is sputtered, which is at a negative bias, which is so high that, despite coating net, a removal of the substrate material. Method according to claim 4, characterized in that that the negative bias in the substrate cleaning up to about -1500 V is set. Method according to claim 4 or 5, characterized in that the negative bias of the at least one substrate ( 3 ) is reduced to an amount less than 400V at the end of substrate cleaning. Method according to one of the preceding claims, characterized in that the negative bias of the at least one substrate ( 3 ) for a layer structure on the at least one substrate ( 3 ) is reduced to about -50V to about -200V. Method according to claim 7, characterized in that that the voltage reduction is continuous or in steps of about 100 V to about 200 V takes place. Method according to one of the preceding claims, characterized in that the substrate pretreatment with Cr, Ti, TiAl, Zr, V, Nb, Ta, W or WC takes place. Method according to one of the preceding claims, characterized in that for the layer structure on the at least one substrate ( 3 ) reactive at least one hard material layer of CrN, CrCN, TiN, TiCN, TiAlN, TiAlCN, TiAlON, ZrN, ZrCN, VN or VCN or non-reactive corrosion-resistant and biocompatible Ti, Nb, Ta or W is deposited. Method according to claims 9 and 10, characterized that for substrate pretreatment and for the layer structure a combination of the listed different coating materials is used. Method according to one of the preceding claims, characterized in that for substrate pretreatment Cr, Ti, W or WC is used and that for the layer structure on the substrate ( 3 ) Carbon is deposited from at least one high purity graphite target. A method according to claim 12, characterized in that the carbon is deposited in a weakly reactive atmosphere of Ar + C ₂ H ₂ or Ar + N ₂ and on the at least one substrate ( 3 ) grows a superhard ta-C, Ta-C: H or aC: H layer. Method according to claim 13, characterized in that that the gas flow of the reactive gas is in a range of about 1% until about 20% of the Ar flow is stopped. Method according to one of claims 12 to 14, characterized in that for a layer structure on the at least one substrate ( 3 ) the deposition of the carbon takes place in an atmosphere with a mixture of Ar and Ne or in pure Ne atmosphere.