Evaporation based micro pump integrated into a scanning force microscope probe
Frederix, P. L. T. M.
de Rooij, Nicolaas F.
Date de parution
Microelectronic Engineering, Elsevier, 2008/85/5-6/1302-1305
A micro pump was integrated into a scanning force microscope probe for circulating liquid through its hollow cantilever and tip. The interior cross section of the cantilever was 2.25 μm × 3.75 μm. All fluidic parts were made of SiO<sub>2</sub>, while the tip apex was made of Si<sub>3</sub>N<sub>4</sub>. The key fabrication techniques were silicon wafer bonding and wet-oxidation. The pumping mechanism was relying on the enhanced evaporation at an enlarged water/air interface at the exit of the microchannel. Capillary forces continuously wetted this interfacial area, thus drawing the liquid through the system. At room temperature, a pump rate of 11 pl s<sub>−1</sub> was experimentally evaluated. The observed temperature dependence of the pump rate could be qualitatively understood by a plain model calculation.
Type de publication
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