Chemorheology of Sol-gel Silica for Patterning High Aspect Ratio Structures by Nanoimprint

Alban Letailleur (1) , Jérémie Teisseire (1) , Nicolas Chemin (2) , Etienne Barthel (1) , Elin Sondergard (1)

1 SVI - Surface du Verre et Interfaces
2 SGR - Saint-Gobain Recherche

Among the existing methods, Nanoimprint Lithography (NIL) emerges as a simple route for surface patterning at the sub-micrometer scale over large areas. Thanks to their tunable properties, sol-gel materials form an alternative class of resist for NIL. However, there is only little understanding of the rheological properties responsible for their good imprint ability. Based on previous works on thermal curing of thermosets, this paper establishes a framework which can be used to tune the imprint conditions and to apprehend the rheological properties of complex hybrids materials. Using a combination of Dynamic Mechanical Analysis (DMA) and scratch test, we were able to model the thermorheological behavior of Methyltriethoxysilane (MTES) gel films during isothermal treatments in a time-temperature-transformations (TTT) diagram. Infrared spectroscopy study of the gel demonstrates the existence, for the same elaboration chemistry, of a condensation threshold independent of the temperature above which the material vitrifies: this reveals the closed relation between the rheology and the chemical microstructure of the gel. We also discussed the strong influence of the elaboration chemistry on the initial microstructure and therefore on the vitrification.

Mots clés: Nanoimprint lithography; sol-gel; rheology

Domaines: Chimie inorganique; Matériaux; Micro et nanotechnologies/Microélectronique

Alban Letailleur, Jérémie Teisseire, Nicolas Chemin, Etienne Barthel, Elin Sondergard. Chemorheology of Sol-gel Silica for Patterning High Aspect Ratio Structures by Nanoimprint. Chemistry of Materials, 2010, pp.10.1021/cm100285b. ⟨10.1021/cm100285b⟩. ⟨hal-00477545⟩