Berlin 2012 – scientific programme
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DF: Fachverband Dielektrische Festkörper
DF 13: Poster II
DF 13.6: Poster
Wednesday, March 28, 2012, 15:00–17:30, Poster E
Restoring the k value in carbon depleted ultra low k surfaces by the silylation of hydroxyl groups with N-trimethylsilylimidazole and dimethyldiacetoxysilane. — Oliver Böhm1,2, Roman Leitsmann2, Philipp Plänitz2, •Christian Radehaus2, Matthias Schaller3, and Michael Schreiber1 — 1Institut für Physik, Technische Universität Chemnitz, 09107 Chemnitz — 2GWT-TUD GmbH, Material Calculation, Annaberger Str. 240, 09125 Chemnitz, Germany — 3GLOBALFOUNDRIES Dresden Module Two GmbH & Co. KG, Germany
To reduce the resistance capacitance delay of integrated circuits, materials with a small k-value - so called ultra low k materials (ULK) - are used as interlayer dielectrics. An important fabrication step in the semiconductor industry is the etching of the trenches, which leads to a carbon depletion and a formation of hydroxyl groups in the ULK material. This results in a moisture uptake and hence an increased k value. To restore the k value, a silylation of the hydroxyl groups can be done. We investigate the silylation of hydroxyl groups by the chemicals N-trimethylsilylimidazole (TMSIM) and dimethyldiacetoxysilane (DMDAS). In particular we use density functional theory to study the different reaction mechanisms. To determine the minimum energy reaction paths as well as transition states, we use the nudged elastic band method. We found significant differences in the activation barriers, reaction energies and the formation of pre and post reaction complexes of TMSIM and DMDAS.