Large Area Production Coatings; Plasma Cleaning and Pretreatment of Large Surfaces
Tuesday, May 1, 2001 1:30 PM in Room Town & Country
G5-1-1 Hollow Cathode Plasma Sources for Large Area Surface Treatment
H. Baránková, L. Bardos (Uppsala University, Sweden)
Generation of plasma over large areas using Hollow Cathode Discharge is described. Different methods are reviewed, including hollow cathode arrays and gas flow sputtering. Radio frequency Linear Hollow Cathodes in several arrangements, for operation at reduced gas pressure and suitable for scale-up, are presented. Hybrid reactors combining hollow cathode plasma with other kinds of plasma are discussed. Non-equilibrium atmospheric plasma source utilizing Fused Hollow Cathode (FHC) with its modular concept can be used for surface treatment of temperature sensitive materials at ambient atmosphere. Examples of surface processing and coating by PVD, both by Hollow Cathode Discharge (HCD) and Hollow Cathode Arc (HCA), are given.
G5-1-3 Large-Area Plasma Cleaning of Steel Strip in a Continuous Air to Air-Process
Otmar Zimmer (Fraunhofer Institute for Material and Beam Technology, Germany); Jrk Richter (von Ardenne Anlagentechnik GmbH, Germany); Bernd Schuhmacher, Christian Schwerdt (Dortmunder OberflächenCentrum GmbH, Germany); Ulf Seyfert (von Ardenne Anlagentechnik GmbH, Germany); P. Siemroth (Fraunhofer Institute for Material and Beam Technology, Germany)
Physical vapour phase deposition (PVD) represents an interesting alternative for steel strip coating instead of conventional processes such as hot-dip coating or electrolytical deposition, giving the product new functional properties. However, for an excellent layer adhesion, PVD-coating of steel strip requires an intensive plasma cleaning of the steel substrate in vacuum prior to PVD-coating, especially in often used air to air-technology. Since usually steel strip coating is performed continuously with strip velocities in the range of 1...4 m/s and with strips width in the order of 1...2 m such plasma cleaning processes must be highly efficient. In this paper, two different plasma-cleaning processes which principally can be scaled up to the usual regime of continuous steel strip coating are presented, on the one hand inverse sputter cleaning and on the other hand arc enhanced plasma cleaning. Technical parameters and cleaning performances of both processes are compared and discussed with results of experimental work. Realization of both processes in a continous air-to-air pilot coating unit are described.
G5-1-4 Multi-Dipolar Plasmas : Concept, Design and Application to Uniform Surface Treatments on Large Areas
Y. Arnal, S. Béchu (Centre National de la Recherche Scientifique, France); A. Lacoste (Institut des Sciences Nucléaires, France); J. Pelletier (Centre National de la Recherche Scientifique, France); T. Lagarde (Metal Process, France)
Besides gas and pumping distribution, the control of plasma uniformity is a necessary condition to obtain the desired uniformity of reactive species and ion bombardment onto surfaces. At industrial level, uniformity of plasma production over square meters and adaptability to given surfaces shapes requires perfect adjustment of power transfer in every part of the plasma source. Achieving this can be obtained by an array of elementary plasma sources where the plasma is produced at ECR on a dipolar magnetron-like field configuration. The interest of such elementary plasma sources lies in their possible assembly in any predetermined surface shapes as well as their scaling up without any physical limitations. Besides surface cleaning, etching, and plasma enhanced chemical vapor deposition on 300 mm wafers, multi-dipolar plasmas can be used for deposition on much larger areas as well as in recent and innovative processes such as plasma-based ion implantation (PBII). The possibilities of multi-dipolar plasma reactors are illustrated with the deposition at room temperature of high quality SiO@sub 2@ films from silane and oxygen gas mixtures. Deposition rates higher than 10 nm per second with a uniformity better than 3 percent are currently obtained on 400 mm x 400 mm substrates.
G5-1-5 A Modular Linear ECR Broad Beam Source for Thin Film Processing
M.Z. Zeuner, F.S. Scholze (IOT - Innovative Oberfläechentechnologien GmbH, Germany); H.N. Neumann (Institut fuer Oberfläechenmodifizierung e.V., Germany)
We present the special microwave excited linear type of ECR (Electron Cyclotron Resonance) broad beam ion source and first results including possible applications in ion beam cleaning, etching and modification. Our source concept overcomes different disadvantages of common linear broad beam ion sources. By means of a modular concept an adaptation at different process requirements with an total beam width of up to 2 m is achieved. Our source consists of modules of 20 cm length arranged in a joined source housing. Each modules bases on a discharge lining from ceramics insulating the discharge plasma and supporting the grid arrangement. Different grid systems are available to shape the beam as required by the process. A special contact arrangement within the ceramics provides for secure and easy electrical contact and gas supply of the source. Each source module gets separately powered by a very compact and reasonably priced autotuning microwave power supply. Permanent magnets placed at the atmosphere side guarantee for an effective discharge heating by utilising the ECR effect. The efficiency of the source is demonstrated analysing the performance in inert and reactive environment. We characterise our ECR ion source by beam profile measurements. An analysis of the beam composition and the energy distribution of the species by means of energy resolved mass spectrometry provides information on chemical reactions and potential conditions in the source. A numerical simulation the beam profile is demonstrated to be a powerful tool in process specific grid design.
G5-1-6 Reactive Sputtering of Dielectrics: Substrate Biasing Problems.
A. Belkind, Z. Zhao (Stevens Institute of Technology); D. Carter, G. McDonough, G. Roche, R. Scholl (Advanced Energy Industries, Inc.)
Substrate biasing in reactive sputtering often presents a number of engineering and system design challenges. Aside from material and thermal concerns, adding substrate biasing to a system typically represents significant costs associated with the addition of a dedicated power supply for this purpose. Use of a dual anode or dual magnetron approach employing a center-tapped isolation transformer provides the process engineer or system designer unique design and control options for addressing this issue in a more cost effective approach. In this case a center-tapped step-up transformer is used to power either a dual anode or dual cathode assembly. By connecting the substrate to a center tap on the secondary coil of the transformer a substrate bias can be achieved. A resistor and/or bias supply can then added to the circuit to manipulate the achieved bias. Al2O3 films were deposited using both dual magnetron and dual anode configurations in this manner. The effects of various resistors and bias voltages on substrate conditions and deposition characteristics were investigated and are reported on here.
G5-1-7 A Versatile Coating Tool for Reactive In-line Sputtering in Different Pulse Modes
P. Frach, K. Goedicke, Chr. Gottfried, H. Bartzsch, S. Klinkenberg (Fraunhofer-Institut Elektronenstrahl und Plasmatechnik, Germany)
Recently, FEP developed a new family of flange mounted magnetron sources together with pulsed powering and process control. This system can be applied either as single magnetrons powered in unipolar pulse mode, e.g. with a pulsed dc voltage, or can be applied as a pair of magnetrons powered in bipolar mode, e.g. with an alternating pulsed voltage between both magnetrons that act alternately as the anode and cathode of the discharge. The pulse unit can be switched between the two pulse modes. This allows to investigate directly the influence of the pulse mode and pulse parameters using the same magnetron configuration and the same type of pulse power supply. Experimental results of the reactive deposition of SiO2, Si3N4 and TiO2 demonstrate the specifics of both process modes. There are effects of the pulse mode observed for all this materials that are independent on the target material. Furthermore we observed effects of the duty cycle, i.e. the ratio of the pulse-on-time to the cycle time of the rectangular current or voltage pulses. The deposition rate and thermal substrate load exhibit a pronounced dependence on the pulse parameters. The values of film properties like refractive index and internal stress will be discussed for the materials SiO2, Si3N4 and TiO2. The flexibility of the pulse sputtering system with free choice of pulse mode allows the universal use either for basic research or in production. The investigations made with this system demonstrate the new possibility to use the pulse parameters to influence film properties.
G5-1-8 On the Vacuum Metallization of Plastics, Composite Materials and Powder Lacquered Aluminium
K. De Bruyn, M Van Stappen (WTCM - Surface Treatment, Belgium); H De Deurwaerder (Coatings Research Institute (CoRI), Belgium); L Rouxhet (CRIF, Beligum); J.P. Celis (Katholieke Universiteit Leuven, Beligum)
This text will describe the work done during the two previous years on the vacuum metallization of different kinds of substrates ranging from plastics (ABS, PC, PP, PA) over a composite material (glass fiber/epoxy resin) to powder lacquered aluminium. The influence on the adhesion of different kinds of pretreatments like flame treatment, chemical treatment, mechanical treatment, oxigen plasma treatment and the deposition of an organic base layer was studied. To measure the adhesion a cross cut + Scotch tape test set-up as well as an impact tester were used. Aluminium, chromium and titanium layers were deposited with different thicknesses using a vacuum magnetron sputter deposition process. Surface roughness and surface morfology were studied using profilometry, SEM and AFM. XPS was used to look at the state of oxidation of the surface after pretreatment. To measure the thickness of the deposited coatings a 4 point resistivity test was succesfully used. .
G5-1-9 Special Aspects Concerning the Electron Beam Deposition of Multi-Component Alloys
Chr. Metzner (FhG-FEP Dresden, Germany)
PVD coatings deposited by electron beam evaporation have been used for many years. This technology is principally qualified to deposit alloys by evaporation from a single crucible. In the last time the electron beam evaporation of multi-component alloys plays a more and more important role. Taylor made substrate layer systems with special functions can be obtained. The composition of the liquid evaporation pool is strongly influenced by the saturation vapor pressures of the particular elements and their differences. The author has investigated the parameters influencing the layer composition and has developed a mathematical model for the calculation of the evaporation and deposition parameters. The so-called activity coefficients of the elements represent the interaction between the components in the liquid evaporation pool. It was found, that there is a strong influence of the activity coefficients on the evaporation in addition to the effect of the different saturation vapor pressures of the elements. The results will be presented at the example of the electron beam evaporation of a special iron-chromium-nickel alloy. Experimental and calculated data will be compared. The developed model for the calculation of the evaporation and deposition parameters of multi-component alloys is universally valid and therefore useful for a lot of applications.