Soft-lithographic patterning of oxide films

The application of some soft-lithographic techniques, e.g. microtransfer molding (µTM), Conventional Micromolding (µM) and specifically micromolding in capillaries (MIMIC) has proven to be a suitable, technically simple and low-cost route to obtain inorganic (mainly oxide) thin films with high fidelity. We make use of MIMIC to pattern ceramic suspensions and sol-gel precursors, where the patterns have periodicities typically between 1 and 5 µm. The MIMIC process is schematically depicted below.

MIMIC process

Elastomeric (PDMS) molds are typically obtained from relief patterned Si or photoresist masters. Subsequently, after the patterning step the precursor is subjected to a heat treatment in order to transform sol-gels into the oxide material or sinter suspensions to higher densities. An example is shown below.

These kinds of micropatterns are very generic structures and could therefore be applied in a wide range of applications, such as miniaturized electronic components, optical waveguides, luminescent pixel displays, scaffolds for biological tissue growth, etc. We are currently developing several kinds of oxide-based line and dot patterns. In order to understand the filling behavior/process of the capillaries better, we are also studying the wetting behavior of water on a number of potential materials for the elastomeric molds.

This project is carried out by Sajid Khan and Ole Göbel.

Daily supervisor: André ten Elshof