Berlin 2018 – scientific programme
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DS: Fachverband Dünne Schichten
DS 17: Poster Session I
DS 17.49: Poster
Tuesday, March 13, 2018, 18:15–20:15, Poster B
Partial Least Square Regression of AES depth profiles and UV-visible spectroscopy for determining oxide layer thicknesses on technical copper — •Jan Stiedl1,2,3, Simon Green3, Thomas Chassé2, and Karsten Rebner1 — 1Reutlingen University, Alteburgstrasse 150, 72762 Reutlingen, Germany — 2University of Tuebingen, Auf der Morgenstelle 18, 72076 Tuebingen, Germany — 3Robert Bosch GmbH, Postfach 1342, 72703 Reutlingen, Germany
In research as in industry, copper is a very commonly used raw material. Due to its electrical properties, copper is used both in battery development and in the development of control units for automotive and non-automotive applications. To ensure the electrical properties and the adhesion of material used in the contacting and packaging technology, the surface of the copper must not be covered by uncontrolled growth of oxide layers. In order to assess this, photoelectron spectroscopy, such as XPS or AES is used. However, these methods are not sufficient for satisfactory statistics and cover-age of production batches. For this purpose, an UV-visible spectroscopy measurement system was developed, which can qualitatively and quantitatively characterize the surface with a Partial Least Square regression (PLS) model in the range of 0 - 50 nm. Superimposed absorption and interference spectra are used to determine oxide layers. PLS is used as a data evaluation tool to establish a regression between the UV-Visible spectra and AES depth profiles. The accuracy of the regression is about 5 %. Already known methods cannot be used in these cases, mostly due to the high roughness of the technical copper surfaces.