Berlin 2008 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 18: Poster Session I - MA 141/144 (Atomic Wires; Size-Selected Clusters; Nanostructures; Metal Substrates: Clean Surfaces+Adsorption of Organic / Bio Molecules+Solid-Liquid Interfaces+Adsorption of O and/or H; Surface or Interface Magnetism; Oxides and Insulators: Clean Surfaces)
O 18.19: Poster
Montag, 25. Februar 2008, 18:30–19:30, Poster F
Aluminum oxide etching with hydrogen — •Markus Reinl, Andreas Assmuth, Rudolf Nüssl, Tanja Stimpel-Lindner, Torsten Sulima, Hermann Baumgärtner, and Ignaz Eisele — Universität der Bundeswehr, Institut für Physik, Werner-Heisenberg-Weg 39, 85577 Neubiberg, Germany
In modern semiconductor production Al is still used as material for the probing and bonding pads. It is widely spread that the difficulties during probing are caused by the native Al2O3 on top of the Al pads. In order to improve the probing performance different hydrogen processes to remove the native oxide were investigated on sputtered Al.
The first experiments were implemented in an UHV chamber. The Al was exposed to H* radicals to investigate the etching behavior. Therefore pure hydrogen was piped through a 1900 K hot tantalum tube into the process chamber. With this configuration a dissociation rate of 90 % can be achieved. The in-situ analysis was done by an x-ray photoelectron spectroscopy (XPS).
The hydrogen plasma experiments were performed in a modular UHV cluster tool with Ar as plasma gas and H2 as etching component. In the purpose of analysis with secondary ion mass spectrometry (SIMS) the cleaned surface needs to be covered with a protective layer in order to avoid a recontamination respectively re-oxidation. Therefore a cap of pure Al was deposited.
As expected the results show that the pure chemical reaction does not lead to a sufficient etching rate. In fact ion bombardment is necessary to achieve a significant etching effect.