Recycling of cantilevers for nanoparticle detection by lift-off technique

Monitoring of engineered airborne nanoparticles is prerequisite to their safe industrial use. Workmen, inhaling particles, are endangered to sustain health hazards. A silicon resonant cantilever sensor has been proven a tool for sampling and recognizing airborne particles at high sensitivity. For repeated usability of the resonator the trapped particles have to be removed which is accomplished by a sacrificial layer deposited on the polluted cantilever surface. Particles, forced by an electrostatic field, settle on top of the layer in spite of the silicon. Within a wet cleaning, not only the additional layer is removed, but also the trapped nanoparticles. This method has been proven by using titanium or conventional photoresist as a covering layer. For the latter, cleaning efficiency is proven by detection of resonant frequency.