DE102007004760A1 - Apparatus and method for coating plate-shaped or band-shaped metallic substrates - Google Patents

Abstract

The invention relates to a device and a method for coating at least one plate-shaped or strip-shaped metallic substrate, wherein a vacuum chamber is provided, in which a magnetron permanent magnet is arranged on the not to be coated side of the substrate, that its magnetic field over the surface of the is formed to be coated side of the substrate, wherein by means of a feed precursor into the vacuum chamber is einlassbar and the substrate is at least temporarily connected as a cathode of a magnetron discharge.

Description

The The invention relates to an apparatus and a method for coating of plates or bands of metal under vacuum conditions, where the deposition of a layer primarily by processes the chemical vapor deposition takes place.

State of the art

devices and methods in the field of physical vapor deposition as well as in the field of chemical vapor deposition are sufficient known. In devices and methods of chemical vapor deposition (also known by the abbreviation CVD) is often a Precursorgas in a vacuum chamber is recessed, leaving behind chemical reaction products of Precursorgases on a substrate to be coated. Such devices and methods are particularly suitable to coat large-area substrates or to achieve high coating rates. Negative affects CVD processes that these are undirected processes where the reaction products next to a substrate to be coated also on all other unprotected internal components precipitate a vacuum chamber.

at the physical vapor deposition (also under the abbreviation PVD known) is a material to be coated either by Heat supply (evaporation) or by sputtering (Sputtering) transferred to the vapor phase and then deposited on a substrate to be coated. When so-called Magnetron sputtering burns a magnetron charge on a target, which is connected as the cathode of the discharge and the coating material stored. Magnetron sputtering processes are also for coating of plates and tapes, especially if thin layers with consistent layer properties to be separated. It is also advantageous that it is sputtering is a directed process. By Suitable measures can be the atomized Particles are primarily accelerated towards the substrate, thereby Parasitic coatings on parts of the vacuum chamber device can be reduced.

The Properties of the layers growing during magnetron sputtering are also affected by the plasma produced during the discharge. Often an intense plasma on the substrate is desired to to obtain good layer properties. The highest intensity however, the plasma is near the target and not on the substrate, so the effect of the plasma for the growing on the substrate layers remains limited.

By Inlet of a reactive gas into a vacuum chamber may be the deposition process also be reactive, d. H. that the layer is made as a product the material of the target and the reactive gas is formed. At the however, the target also becomes reactive magnetron sputtering occupied with reaction products, whereby parameters of the discharge and influences the properties of the layers growing on the substrate can be. In many coating systems, the deposition process must be stabilized by complex control processes.

When Reactive gas in magnetron sputtering can also be a precursor in a Vacuum chamber are admitted. This will produce both a chemical vapor deposition by splitting the molecules of the precursor in the plasma the magnetron discharge and a condensation of the cleavage products the substrate as well as a physical vapor deposition by sputtering and depositing the target material.

Out WO 03/048406 Devices and methods are known that combine both features of CVD and PVD processes. Within a vacuum chamber, target material disposed on a cathode is atomized by physical means. At the same time, a precursor can also be introduced into the vacuum chamber, as a result of which reaction products of the sputtered target material and the precursor are deposited on a plate-shaped substrate arranged at least close to the anode. In this case, a magnetron is located on the non-coated side of the substrate such that its magnetic field is formed primarily over the surface of the side of the substrate to be coated. In this way, the intensity of the plasma can be increased slightly near the substrate. However, the disadvantage here is still that due to the Precursorgases all components are coated in the interior of the vacuum chamber and here in particular the target surfaces, since in their environment the highest plasma density is present. In particular, during the deposition of electrically insulating layers of the process of sputtering is thereby significantly disturbed, the discharge can be completed in a short time completely. Furthermore, an increase in the plasma intensity near the substrate due to the additional magnetic field is achieved only to a small extent.

task

The invention is therefore the technical problem of providing a device and a method by which the disadvantages of the prior art can be overcome. In particular, it should allow apparatus and methods, layers on plate-shaped or band Shaped metallic substrates deposited by CVD processes, in which also electrically insulating layers can be deposited long-term stable and with homogeneous properties.

The Solution of the technical problem results from the objects with the features of claims 1 and 16. Further advantageous embodiments of the invention will become apparent from the dependent claims.

A inventive device and an inventive Process for coating at least one plate-shaped or band-shaped metallic substrate are distinguished through a vacuum chamber in which a magnetron permanent magnet so arranged on the non-coated side of the substrate is that its magnetic field is above the surface is formed to be coated side of the substrate, by means of a feed a precursor einlassbar in the vacuum chamber is and the substrate at least temporarily as a cathode of a magnetron discharge is switched. Due to the fact that the closed track of the magnetron discharge (also called racetrack) directly above the to be coated Side of the substrate burns, there will be a plasma with a very high intensity, which helps to increase the Coating rate contributes. This has an advantageous effect also that it is a cathode-side plasma. The ionized material particles in the plasma, which predominantly have a positive electric charge, are due to the cathodically connected substrate attracted by this and thus accelerated once again. An inventive Device and a method according to the invention are therefore particularly suitable dense and optionally hard layers deposit. The electrical voltage between the cathode and anode is According to the invention 100 V to 500 V.

At the Injecting the precursor, it is advantageous if this means several evenly distributed nozzles is introduced directly into the plasma zone over the substrate surface to be coated. A uniform movement of the substrate in the coating direction with constant speed leads to a homogeneous Layer on the substrate surface.

at According to one embodiment, the substrate is the discharge current pulsed supplied. This is advantageous, for example during the deposition of electrically insulating layers. That too Applying an AC voltage is possible. Depending on requirements with regard to the electrical properties of the deposited Layers and the layer thickness will be a frequency in the range of 10 kHz to 500 kHz selected.

For the discharge requires another electrode, the is switched as an anode. As an anode, for example, a metallic Vacuum chamber wall can be used.

at an alternative embodiment has a to be coated Substrate the same electrical potential as the vacuum chamber. Therefore, it is necessary to have a separate anode in the vacuum chamber contribute. The anode is preferably arranged in such a way that this the opposite side of the substrate to be coated lies. In a preferred embodiment, the anode is cup-shaped, wherein the opening of the substrate is facing. Anode and substrate limit in this way at least partially a volume in which the inlet port of the precursor ends. The base of the "anode pot" can have any round, oval or square shape.

Around to prevent the magnetron discharge in unwanted Way to other components within the vacuum chamber, is an electrical shield advantageous, which hood-shaped formed surrounds the anode. The towards the substrate directed opening of the hood-shaped shield (also called dark field shielding) is used close to the substrate. hereby will also be a partial overpressure of the incoming Precursors generated in anode and substrate limited volume. The gap between the substrate and the metallic shield becomes It is designed so small that the plasma in the anode and substrate limited volume remains concentrated. For an effective Dark field shielding should be the gap between substrate and shield do not exceed a range of 1 mm to 10 mm. This However, gap can be made larger, for example be when between substrate and shield a metallic Sheet metal or a stack of spaced metallic sheets, which are substantially parallel to the substrate surface run, is / are arranged. However, should also the Distance between the shield and adjacent plate, between the individual adjacent sheets and between substrate and adjacent Sheet not larger than 1 mm to 10 mm each be. In this way, on the one hand increases the cross section through which the gas is confined to that of the anode and substrate Volume in the outer area of the vacuum chamber on the other hand it prevents the discharge burns out of the limited volume of the shield and substrate.

In a further embodiment, a magnetron is arranged within the vacuum chamber, by means of which a portion of the material required for the layer deposition by sputtering a Targets are provided on the magnetron. In this case, an electrode of the magnetron is temporarily connected as an anode with respect to the substrate cathode. Substrate and electrode are periodically switched alternately as cathode or anode. For sputtering of the target, it is advantageous if, in addition to the precursor, a sputtering gas is admitted into the vacuum chamber.

A Another embodiment results when the for the magnetron discharge on the substrate required anode a hot evaporating material is formed. The evaporation material is stored in a crucible and as the anode of the magnetron discharge connected. As an energy source for the evaporation is preferably used an electron beam generated by an electron gun becomes. Depending on the evaporation material, the energy source for the evaporation also be another, such as a radiant heater or induction evaporator. The advantage of this embodiment is that the anode by evaporation is always from deposits of the CVD process and the process over a long time a metallic surface with good contact offers to the plasma. In this way, material from the evaporation material additionally installed in the layer to be deposited. These Embodiment is therefore particularly suitable for deposition of electrically insulating layers.

embodiment

The Invention will be described below with reference to preferred embodiments explained in more detail.

The Fig. Show:

1 a schematic representation of a device according to the invention;

2 a schematic representation of an alternative device according to the invention.

In 1 is schematically a device 101 represented by means of within a vacuum chamber 102 on a 100 m long, 50 cm wide and 0.5 mm thick strip-shaped steel substrate 103 a transparent and hard layer is to be deposited. This is done via an inlet 104 the precursor HMDSO in the vacuum chamber 102 admitted. On the non-coated side of the substrate 103 is a magnetron permanent magnet 105 arranged such that its magnetic field over the surface of the side to be coated of the substrate 103 is trained. On the side of the substrate to be coated 103 is inside the vacuum chamber 102 a cup-shaped anode 106 , which consists of copper and is formed water-cooled. By means of a power supply device, not shown, is connected between the connected via a sliding contact as a cathode substrate 103 and the anode 106 an electrical voltage of about 200 V is applied, creating a discharge between the cathode 103 and anode 106 ignited and a plasma 107 is trained. This shows the plasma 107 the highest intensities in the areas in which the magnetic field of the magnetron permanent magnet 105 is formed over the substrate surface.

So that the plasma is mainly in the anode 105 and substrate 103 forms a limited area encloses a hood-shaped shield 108 whose opening is oriented towards the substrate, the anode 105 , The shield 108 consists of sheet steel and is designed as a so-called dark field shielding. Between the edge of the shield 108 and the substrate 103 is a stack of 2 mm thick copper sheets 109 arranged, each spaced 3 mm apart and aligned substantially parallel to the substrate surface. On the one hand, the dark-field shielding is maintained by the copper sheets and, on the other hand, the cross-section through which the precursor gas or its cleavage products escape from the region bounded by the shield and substrate and can be pumped out of the vacuum chamber by pumping devices.

through The described device was able to deposit a transparent layer which primarily comprises the elements Si, C and O, which is a Hardness of 18 GPa and at the ratio of oxygen and silicon one to three relative to those Atomic percent.

An alternative embodiment of a device according to the invention 201 is in 2 shown schematically. Inside a vacuum chamber 202 should be on a 200 m long, 30 cm wide and 1 mm thick strip-shaped aluminum substrate 203 a Ti: C: H layer are deposited. Behind the substrate 203 is again a magnetron permanent magnet 205 arranged, which over the surface to be coated of the substrate 203 forming a magnetic field. The chemical elements required for the layer deposition are on the one hand via an inflow 204 through which the precursor acetylene into the vacuum chamber 202 on the other hand in an evaporator crucible 210 in which titanium material 211 is stored, provided. An electron gun 212 generates an electron beam 213 , by means of which the surface of the titanium material 211 periodically scanned, thereby heated and finally transferred to the vapor phase. The application of a voltage of 300 V between the substrate connected as a cathode 203 and the evaporator crucible connected as an anode 210 including titanium material 211 leads to a magnetron discharge between the cathode and the anode and to form a plasma 207 with a high plasma density directly above the surface of the substrate to be coated 203 , The reaction particles of the vaporized titanium and the precursor constituents are deposited on the substrate surface. The deposition process is thereby reinforced by the fact that the substrate is connected as a cathode, since the majority of the ionized material particles in the plasma are provided with a positive electrical charge.

Again, as already too 1 described, the anode (evaporator crucible 210 and titanium material 211 ) with an electrical shield 208 provided, which encloses the anode and is formed open on the substrate side, wherein between the edge of the shield and the substrate 203 again a stack of spaced sheets 209 made of copper.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• WO 03/048406 [0007]

Claims (26)

Apparatus for coating at least one plate-shaped or strip-shaped metallic substrate, comprising a vacuum chamber, in which a magnetron permanent magnet is arranged on the side of the substrate not to be coated such that its magnetic field is formed over the surface of the side of the substrate to be coated, wherein by means of a feed, a precursor can be introduced into the vacuum chamber, characterized in that the substrate is at least temporarily connected as a cathode of a magnetron discharge. Device according to claim 1, characterized in that that the vacuum chamber is formed as an anode of the magnetron discharge is. Device according to claim 1, characterized in that that a separate anode for the magnetron discharge within the vacuum chamber on the side of the substrate to be coated is arranged. Device according to claim 3, characterized in that that the substrate is connected to the electrical vacuum chamber mass is. Apparatus according to claim 3 or 4, characterized that an electrical shield open to the substrate is the anode encloses. Device according to claim 5, characterized in that that between the substrate and the shield a metal sheet or arranged a stack of a plurality of spaced metal sheets is, wherein the metal sheet or the metal sheets are substantially parallel are aligned to the substrate surface. Apparatus according to claim 5 or 6, characterized that the adjoining elements shielding, sheet metal and substrate at a distance of 1 mm to 10 mm. Device according to one of claims 5 to 7, characterized in that the supply for the precursor into the volume bounded by the shield and the substrate is led into it. Device according to one of claims 3 to 8, characterized in that an electrode of a magnetron is designed as an anode for the magnetron discharge. Device according to claim 9, characterized in that that the substrate and the electrode alternately cathode or anode the magnetron discharge are. Apparatus according to claim 9 or 10, characterized through a sputtering gas inlet. Device according to one of claims 3 to 8, characterized in that the evaporation material of a Evaporator device connected as the anode of the magnetron discharge is. Device according to claim 12, characterized in that that the evaporator device is designed as an electron beam evaporator is. Device according to one of the preceding claims, characterized in that the substrate pulsed energy can be supplied is. Device according to one of claims 12 to 14, characterized in that the substrate with AC voltage can be acted upon. Process for coating at least one plate-shaped or band-shaped metallic substrate in a vacuum chamber, in which a magnetron permanent magnet on the not to coating side of the substrate is arranged that the Magnetic field over the surface of the to be coated Side of the substrate is formed, wherein by means of a feed introduce a precursor into the vacuum chamber, characterized that the substrate at least temporarily as a cathode of a magnetron discharge is switched. Method according to claim 16, characterized in that in that the vacuum chamber is connected as the anode of the magnetron discharge becomes. Method according to claim 16, characterized in that that a separate anode for the magnetron discharge within the vacuum chamber on the side of the substrate to be coated is arranged. Method according to claim 18, characterized that the substrate is connected to the electrical vacuum chamber mass becomes. Method according to claim 18 or 19, characterized that is an open to the substrate electrical shield, which enclosing the anode is used. Method according to claim 20, characterized in that that between the substrate and the shield a metal sheet or arranged a stack of a plurality of spaced metal sheets is, wherein the metal sheet or the metal sheets are substantially parallel be aligned to the substrate surface. Method according to one of claims 18 to 21, characterized in that constituents of the deposited layer material provided by magnetron sputtering within the vacuum chamber become. Method according to one of claims 18 to 21, characterized in that constituents of the deposited layer material be provided by evaporation within the vacuum chamber, wherein the material to be evaporated as the anode of the magnetron discharge is switched. Method according to claim 23, characterized the evaporation material evaporates by means of an electron beam becomes. Method according to one of the preceding claims, characterized in that supplied to the substrate pulsed energy becomes. Method according to one of the preceding claims, characterized in that the substrate is DC or AC voltage is applied.