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Evaporation based micro pump integrated into a scanning force microscope probe
Auteur(s)
Heuck, F.
Hug, T.
Akiyama, Terunobu
Frederix, P. L. T. M.
Engel, A.
Meister, André
Heinzelmann, Harry
de Rooij, Nicolaas F.
Staufer, Urs
Date Issued
2008
Journal
Microelectronic Engineering, Elsevier, 2008/85/5-6/1302-1305
Abstract
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.
Publication type
journal article
