DD141932A1 - METHOD AND DEVICE FOR PARTICLE CURRENCY AND HIGH-RATE COATING - Google Patents

Abstract

The invention relates to a method and apparatus for generating ionized Teilchenstroeme and for depositing them on a Traeger. The object and the object of the invention to be solved are to provide a method and a device which enable the high-rate deposition of layers optionally also on large surfaces and allow an increase in the density of the ion carrier or ion current component reaching the layer carrier. According to the invention, neutral or partially ionized dense and / or vaporous particle streams are passed through a hollow cathode which is surrounded by self-contained pole shoes of one or more permanent magnets or electromagnets. In systems of suitable voltage between the hollow cathode and an anode, a significant portion of the particle current is ionized in the resulting hollow cathode annular gap discharge. The extraction of the ionized particles is carried out with the aid of an ion extraction system, by applying an acceleration voltage between hollow cathode and layer carrier or by the negative wall potential of the electrically insulated, in contact with the discharge plasma Schichttraegers. The invention is applicable: microelectronics, surface trimming, wear reduction and corrosion protection

Description

Process and apparatus for particle striation and high rate coating

Fields of application of the invention

The invention is applicable in the fields of technology that require layers with specific properties, such. As the coating and layering in microelectronics, optoelectronics and optics, for surface treatment, for corrosion protection and to reduce wear.

Characteristic of the known technical solutions

Methods for producing ionized particle streams and depositing them on a support are already known. This process includes ion beam sputtering, ion plating, ion beam deposition of thin films, and ion beam nitriding of plaque body surfaces.

The common feature of these methods is that at least part of the elements or compounds involved in the layer construction are delivered as ions, the energy and momentum of the particle carrier passing to the substrate appearing as a cause for the formation of specific layer properties or compounds, and that the layer deposition can be done except in the case of plasma-assisted ion plating in a high vacuum. In ion beam sputtering - (DD-WP 76283), the starting material referred to as target is characterized by a in a Io-

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nenquelle generated atomized atomized. The atomized particle strorage, which forms a layer on the correspondingly arranged support, contains only a small proportion of ions; the average energy of the particles is 5 to 10 eV. In ion beam sputtering (DD-WP 130 157), an ion current from a separate ion source is directed onto the carrier simultaneously with the sputtered particle stream, so that an additional variable energy, momentum, and particle supply takes place in the growing layer. These methods were previously used because of the independently variable experimental parameters mainly in basic research. For industrial coatings, the achievable layer growth rates and coating areas are still too low; The ion content in the atomized particle stream is physical and can not be varied. In the ion-plating method (DE-AS 15215 ^ 1), a fraction of the material vaporized or vapor-deposited or gasified is ionized in a low-pressure gas discharge plasma plasma and applied to the electric field between the substrate and an auxiliary electrode Carrier accelerates. The gas discharge forms heretofore used for this process do not allow the ratio of ions having energies up to several 100 eV to neutral particles in the carrier particle stream to be such as to allow a high rate of deposition with simultaneous delivery of up to several 10 eV of energy per deposited layered particle is. Higher ion energies lead to the formation of structural defects in the growing layer and to the re-atomization of the layer material. Furthermore, the deposition of compound, alloy and doped layers using this method is only possible with difficulty.

In ion beam deposition (DE-OS 2113375) of layers, the entire material used for layer construction is ionized in an ion source and accelerated to the surface to be coated. This process is very expensive

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and allows mainly only the deposition of layers of chemical elements. The layer growth rates achieved so far are low.

In ion beam nitriding (DD-WP 130 157), nitrogen ions act on the solid body connected as a target, the temperature of the solid surface being adjusted, for example by radiation heating, to a value suitable for the plague diffusion of the nitrogen particles and the compound formation. Purely an effective application of this method, the previously achieved ion current densities and treatment areas are too low.

Object of the invention

It is the object of the invention to produce a high ion content in the particle stream and to substantially increase the growth rate of the deposited layers.

Explanation of the essence of the invention

The invention has for its object to develop a method and an apparatus which have a generation of ionized particle streams and their deposition on a carrier to the content, wherein the high-rate deposition of Einkomponentenschichten-, bonding layers and doped layers should be made optionally on large areas.

The deficiency of the known solutions are due to the fact that in the ion beam sputtering and Ionenzrahlzeretäubung the sputtered from the target, the carrier-reaching particle flow of ionic strands on the target and the Zerstäubungsausbeute is determined. The sputtering yield can not exceed a limit depending on the ionic, ionic and target material; The ion current density of the known large-area ion sources is a maximum of several mA / cm, so that the layer growth rate of ion-beam-sputtered layers does not exceed a limit that is for metals at 50 nm / min. Due to the limited ion current density of the known large area ion sources, the layer growth rate in ion beam deposition is

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and ion beam nitriding also limited. In the known ion-plating method, the density of the ion beam reaching the substrate is low because of the low plasma density of the low-pressure gas discharges used; the energy of the ions must not exceed a threshold, the exceeding of which would lead to the formation of defects in the growing layers. Sufficient energy and pulse supply into the growing layer can thus be achieved only at limited layer growth rates. , Increasing the layer growth rate with sufficient energy and pulse supply into the growing layer requires an increase in the density of the ion current or ion current component reaching the substrate.

According to the invention the object is achieved in that neutral or teilionisierte gas and / or vapor partial. chen currents passed through a hollow cathode and / or generated in this, which is surrounded by self-contained pole pieces of one or more permanent or electromagnet, so that forms an inhomogeneous, tunnel-shaped, closed magnetic field in the range of action of Polschuhpaares on the Hohlkatodenoberfläche, which Electron trap works. When a suitable voltage is applied between the hollow cathode and the anode arranged near the particle flow inlet and / or outlet side, the resulting hollow cathode discharge, predominantly in the region of the pole shoe pairs, is thus superimposed on an annular gap charge. In the gas discharge plasma, whose density in the hollow cathode annular column discharge reaches high values, a significant portion of the particle flow is ionized. In addition to the particles introduced, the gas discharge plasma contains neutral and ionized particles of the hollow cathode surface, which are atomized by ion bombardment as a result of the special discharge mechanism. With sufficiently intensive atomization of Hohlkatoden- 'surface, the discharge can be maintained even after switching off the introduced particle flow. The extrak

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tion of the ionized particles from the gas discharge plasma and their acceleration on the support is carried out by means of a suitable ion extraction system or by applying an acceleration voltage between hollow cathode and substrate or by the self-adjusting, negative wall potential of the electrically isolated, but in contact with the discharge plasma mounted carrier.

The energy of the gas-kinetic stream of neutral and plasma-excited particles can be influenced by the shape of the hollow cathode, for example by forming a nozzle; by collisions with the ions there is a further increase in energy. By different shaping of the discharge space and the magnetic field, the device is further adapted to the substrate geometry. The proportion of sputtered particles from the cathode surface in the particle stream to the substrate iet also variable due to the distribution characteristics of the sputtered material by the shape of the discharge space. According to the invention, the discharge space of the hollow-cathode annular gap discharge is optionally cylindrical, hollow-cylindrical, frustoconical, rotationally ellipsoidal or prismatic and flows through the particle stream in the axial direction, or the discharge space is annular with prismatic, elliptical or trapezoidal cross-section and is flowed through in the radial direction. In order to increase the coating area and thus the productivity, in a further embodiment of the invention, a plurality of hollow cathodes, which are surrounded by self-contained pole piece pairs of one or more permanent magnets or electron magnets, are arranged parallel to one another. The particle stream used is a noble gas and / or a gas containing at least one material component and / or the alloying or doping material of a layer to be deposited or deposited on the support.

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The production of contamination-free one-component layers, tie layers, alloy layers or doped layers is made possible in that the wall of the hollow cathode consists of the layer material or of a component or sectorwise of the components thereof and / or of the material intended for the alloying or doping of the layer, or is occupied. The individual sectors are further optionally each surrounded by a self-contained pair of pole pieces and receive the same or different, separately controllable electrical potentials, whereby the proportion of different material components in the layer can be varied. For the same reason, the magnetic flux in the existing pairs of pole shoes is optionally regulated separately and set to different values. In order to achieve a long service life of the hollow cathode, the location of the strongest removal of the hollow cathode wall is displaced by displacement of the pole shoes, or the cathode material, with appropriate formation of the hollow cathode by suitable supply means running. added.

The ignition and maintenance of the hollow cathode ring gap discharge at low voltages and an increase in the plasma density can be achieved by irradiation of additional electrons or by introducing a plasma jet or a pre-ionized particle beam in the discharge. In a further embodiment of the invention, the device is therefore connected downstream of a device for generating an electron beam, a plasma jet or a pre-ionized particle beam, wherein the hollow cathode of the closest electrode of this device relative to the hollow cathode receives a positive potential and thus simultaneously the anode of the hollow cathode annular gap discharge represents. The apparatus can be connected downstream, for example, Pinkelstein type ion sources, wherein the extraction electrode of the ion source with respect to the emission electrode of the ion source receives a positive potential and is simultaneously switched as an anode of Hohlkatodenringspaltentladung.

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embodiment

The invention will be explained in more detail in three exemplary embodiments. In the accompanying drawings show:

1: the device with a cylindrical discharge space,

2: the device with hollow cylindrical discharge space,

3: the device with annular discharge space,

In the first embodiment (FIG. 1), the hollow cathode 3 is tubular, so that a cylindrical discharge space 4 is formed. The hollow cathode is annularly surrounded by the PoI-shoe pair 5 of an electric or permanent magnet 6. At the inlet of the particle stream 1 through the openings of the disk-shaped anode 2 and applying a voltage U. a hollow cathode discharge is ignited and maintained in the pressure range of 0.1 ... 1 Pa, which predominantly in the region of the magnetic field whose field lines in the region of PoI Pair of shoes 5 parallel to the hollow cathode surface, and the electric field, which is directed starting from the discharge plasma perpendicular to the hollow cathode surface, is superimposed by an annular gap discharge. The degree of ionization and the charge carrier density reach very high values in the plasma of the emerging hollow-cathode ring-gap discharge, so that a considerable proportion of the introduced particle current is ionized. Due to the present discharge mechanism, the surface of the hollow cathode 3 is atomized predominantly in the region of the pole shoe pair 5 by ion bombardment.

The sputtered particles are also partially ionized in the discharge and mix in the introduced particle stream 1 at. By varying the discharge voltage U 1 and the magnetic field, both the density and the energy of the ions accelerated from the plasma boundary layer to the hollow cathode surface and thus the amount of dusted material as well as the degree of ionization and the charge carrier can be determined.

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Density can be controlled in the plasma, so that there is a certain ratio of introduced to sputtered particles and ions to neutral in the discharge plasma. The extraction of the ionized particles and their acceleration on the holder 10 fixed to the substrate 9 takes place in the present example with the aid of a Zweielektrodenextraktions sy st ems with multiple emission openings, the emission electrode 7, the potential of the hollow cathode 3 and the acceleration electrode 8, the voltage U _ß compared to Hollow cathode 3 obtained. At the same time, a gas-kinetic stream of neutral particles passes to the substrate 9. The extraction system also acts as a pressure stage, so that the coating can be carried out under high vacuum conditions.

Another possibility of ion extraction is that the substrate is connected as an acceleration electrode. In this ion plating variant, emission and acceleration electrodes 8 are omitted; the substrate 9 is positioned at the location of the accelerating electrode and receives the potential U ^ with respect to the plasma. The coating of a carrier can also take place in that substrate 9 and holder are mounted electrically insulated and positioned at the location of the emission electrode 7 when the emission and acceleration electrode 7, 8 is omitted. Due to the direct contact of the electrically insulated layered carrier 9 with the discharge plasma, its surface charges negatively except for the wall potential and causes the ion extraction from the plasma.

In the second exemplary embodiment (FIG. 2), the hollow cathode 3 consists of the inner cathode tube 11 and the outer cathode tube 12, which, when placed in one another, form a hollow-cylindrical discharge space 4. The two cathode tubes 11, 12 are each surrounded by a pole piece pair 5 of an outer and inner electric or permanent magnets 13, 14 annular. The anode 2, the emission 7 and acceleration electrode 8 and the holder 10 for the substrate 9 are formed disc-shaped.

In the third embodiment (Pig * 3), the hollow cathode of two disc-annular cathodes 15 »16 is formed, so that an annular discharge space 4 is formed with a rectangular cross-section. An annular pole shoe pair 5 of an electric or permanent magnet 17, 18 is arranged on the side of each cathode 15, 16 facing away from the discharge space 4. The anode 2, the emission and extraction electrodes 8 are tubular; the holder 10 for the substrate 9 is tubular or has the shape of a prismatic lateral surface ·

The inlet of the particle stream 1, the ignition and Aufrechterhal tion of the discharge, the ionization of the particle stream 1, the sputtering of the Hohlkatodenoberflächen, the ion extraction and the coating in the same manner as in the first embodiment with the difference that the two cathode tubes 11, 12th In the second embodiment and the two disc-annular cathodes 15 .16 · can consist of different material in the third embodiment and that by separately controlling the magnetic field strengths in the existing magnet and by applying different potentials U ^ and U ^ ₂ n the cathodes, the sputtering rate of the cathode surfaces and thus the proportion of the respective cathode material in the particle stream 1 to the substrate 9 can be varied. With the ion-plating variant described in the first exemplary embodiment, for example, hard, transparent carbon layers could be deposited with the following parameters:

Material of the hollow cathode: Graphite introduced particle flow: 90 % methane / 10 % argon pressure in the coating space: ρ = 0.3 Pa Discharge voltage: U. = 300 V

Acceleration voltage: Ug = 100 V layer growth rate: 500 nm / min

Claims (3)

- ίο - 209 84 6 Claim for invention 1.6. Proceduresafter items 1 to 1.5. , characterized in that the Hohlkatoden-annular gap discharge at sufficiently high, caused by intensive atomization removal rate of Hohlkatodenoberfläche and by appropriate shaping of the discharge space, for example by concave discharge space walls and small cross section of the particle flow outlets, after switching off the particle flow is operated. 2. Apparatus for carrying out the method according to item 1 to 1.6, characterized in that the hollow cathode (3) of self-contained pole pieces (5.) of one or more permanent or electromagnets (6) is surrounded, near the Teilchenstromeintritts- and / or exit side an anode (2) is arranged and near the particle flow exit side of the hollow cathode (3) optionally an extraction electrode system is mounted, for example, the emission electrode (7) and accelerating electrode (8), or between the substrate (9) and hollow cathode ( 3) or anode (2) an acceleration voltage (Ug) is applied or the support (9) is arranged electrically isolated near the hollow cathode (3). 2.1. Device according to point 2, characterized in that the discharge space (4) of the hollow cathode annular gap discharge is optionally cylindrical, hollow cylindrical, truncated cone-shaped, rotationally elliptic or prismatic and flows through the particle stream (1) in the axial direction, or annularly with prismatic, - 209 84 6 is formed elliptical or trapezoidal cross-section and is traversed by the particle flow (1) in the radial direction. 2.2. Device according to point 2. and 2.1, characterized in that a plurality of hollow cathodes (3), which are surrounded by self-contained pole shoes (5) of one or more permanent or electromagnets (6), are arranged parallel to each other. 2.3. Device according to items 2 to 2.2, characterized in that the hollow cathode (3) is composed of successively arranged sectors, the sectors
optionally of pole pieces (5) are each a permanent or electromagnet (6) are surrounded and optionally receive the same or different, separately controllable electrical potentials. 2.4. Device according to point 2. to 2.3 , characterized in that the magnetic flux in the pole pieces (5) of each permanent or electromagnet (6) is separately controllable and adjustable to different values. 2.5. Device according to point 2. to 2.4. t characterized in that the pole pieces (5) are arranged displaceably. 1.5. Procedure according to point 1. to 1.4. _y characterized in that the cathode material is continuously supplemented at the place of the strongest erosion. 1.4. Method according to item 1 to 1.2, characterized in that the hollow cathode consists of pure or doped silicon and is used as a gas silane. 1.3. Process according to items 1 to 1.2, characterized in that the hollow cathode consists of carbon and a methane / argon gas mixture and / or polycyclic hydrocarbons are used as the particle stream. -11 - 209 84 6 1.2. Method according to item 1 and 1.1, characterized in that the hollow cathode consists of the layer material or of a component or sectorwise of the components thereof and / or of the material intended for the alloy or the doping of the layer or is occupied therewith. 1.1. Method according to item 1, characterized in that the particle stream used is a noble gas and / or a gas which contains at least one material component and / or the doping or alloying material of a layer to be deposited or deposited on the support. 1. A method for Teilchenstromionisierung and high-rate coating using known means for vacuum generation, the gas and / or steam inlet, for the generation of magnetic fields and the power and power supply ₉ characterized characterized; a neutral or partially ionized gaseous and / or vaporous particle stream is passed through a hollow cathode in which an inhomogeneous, tunnel-shaped, closed magnetic field is generated, which acts as an electron trap and / or is generated therein, when a suitable voltage is applied the hollow cathode and an anode form and overlap a Hohlkatcden discharge and an annular gap discharge, is ionized in Gaeentladungsoplasma the Hohlkatoden-annular gap discharge a significant portion of the particle stream and then the ionized particles are extracted from the gas discharge plasma and accelerated onto a carrier. 2.6. Device according to points 2 to 2.5, characterized in that the device is followed by a device for generating an electron beam, a plasma jet or a pre-ionized particle beam and that the hollow cathode (3) closest Elek - - trode this device simultaneously the anode (2) represents the hollow cathode ring gap discharge. For this 3 pages drawings