Georges Dubourg

All‐Organic Microelectromechanical Systems Integrating Specific Molecular Recognition – A New Generation of Chemical Sensors

Cantilever-type all-organic microelectromechanical systems based on molecularly imprinted polymers for specific analyte recognition are used as chemical sensors. They are produced by a simple spray-coating-shadow-masking process. Analyte binding to the cantilever generates a measurable change in its resonance frequency. This allows label-free detection by direct mass sensing of low-molecular-weight analytes at nanomolar concentrations.

Collective fabrication of all-organic microcantilever chips based on a hierarchical combination of shadow-masking and wafer-bonding processing methods

This paper describes a new collective microfabrication process of all-organic microcantilever chips. This method is based on the hierarchical combination of shadow-masking and wafer-bonding processes. The shadow-masking combines deposition and patterning in one step thanks to spray-coating through a polymer microstencil that allows patterning of thermosensitive materials such as PMMA. The shadow-masking parameters have been optimized to obtain suspended microcantilevers characterized by a convenient thickness profile. The resulting PMMA structures were then transferred onto SU-8 chips by using an SU-8 wafer-bonding process. The effect of the UV exposure dose of both SU-8 layers in contact on the bonding quality has been investigated and optimized. With the optimized bonding process, we have achieved the large-scale transfer of microstructures with a yield of 100% and a bond strength of 50 MPa. These microcantilevers were also tested at resonance to determine Youngs moduli of patterned polymers. The low values obtained (below 5 GPa) make these organic MEMS structures strong candidates for highly sensitive sensing applications when used in the static mode.