Abstract
This paper examines wet and dry fabrication of vertical micro-mirrors in (110) silicon for use in an innovative BioMEMS integrating gripping and micro force sensing functionalities. Wet anisotropic chemical etching in potassium hydroxide (KOH) and tetramethyl ammonium hydroxide (TMAH) with and without isopropanol alcohol (IPA) additive was examined. Deep Reactive Ion Etched samples were produced using inductive coupled process. 3D surface roughness of samples was examined using scanning electron microscope, interferometric profilometer and atomic force microscopy. An optic fiber displacement sensor was exploited to measure the reflectivity of uncoated or coated samples with evaporated metallic thin film. The research aimed to find optimal fabrication technique for fabricating vertical micro-mirrors in polymer based BioMEMS. TMAH etched silicon samples with surface roughness R a = 15.1 nm showed highest reflectivity of all structures fabricated, reflectivity was more than doubled by adding a 10 nm layer of evaporated aluminum coating.
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Acknowledgments
Financial support of EPSRC and IDB Technologies Ltd. towards a PhD Studentship for R.E.M. is acknowledged. The authors would like to express gratitude to Dr Camelia Dunare at the SMC, University of Edinburgh for providing DRIE samples; Dr Robert Keatch for constructive discussions; Martin Kierans for help provided using the SEM and Dr Gary Callon for general support in the cleanroom at University of Dundee. Finally, Mark Rainer for help provided using the Zygo interferometer at the University of Cambridge.
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Mackay, R.E., Lionis, N. & Le, H.R. 3D surface topography and reflectivity of anisotropic etched silicon micromirrors for BioMEMS. Microsyst Technol 17, 1763–1770 (2011). https://doi.org/10.1007/s00542-011-1362-3
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DOI: https://doi.org/10.1007/s00542-011-1362-3