Metal-coating of polymer cantilevers

Contact:

Stephan Keller, DTU Nanotech, 4525-5846 (stephan.keller@nanotech.dtu.dk)

(a) Principle of surface stress sensor (b) Gold-coated polymer cantilevers.

A cantilever is a beam that is clamped at one end and free-standing at the other. In biosensing cantilevers are used as surface stress sensors (Figure (a)). There, one surface of the cantilever is functionalized with receptor molecules. If analyte molecules bind to the receptors, surface stress is generated due to molecular interactions, and the cantilever is deflected. This bending is typically measured by a laser beam reflected at the apex of the cantilever. In the Nanoprobes group, polymer cantilevers are used for this purpose (Figure (b)). These structures have to be covered by a thin metal film to ensure the reflection of the laser beam and to allow for the attachment of receptor molecules to the cantilever surface. Unfortunately, the metal deposition process often results in bending and deformation of the polymer cantilevers which is not suitable for their use as biosensors.

The goal of this project is the optimization of the metal deposition process in the cleanroom at Danchip. First, polymer cantilevers are fabricated using standard photolithography. Then, the influence of the metal deposition on the initial bending of the cantilevers is compared. Finally, optimal process conditions for the metal-coating of polymer cantilevers will be defined.