Collective fabrication of an in-plane silicon nanotip for parallel femtoliter droplet deposition

• Published in: Journal of micromechanics and microengineering 2007-01, Vol.17 (1), p.N1-N5
• Main Authors: Saya, D, Leïchlé, T, Pourciel, J B, Bergaud, C, Nicu, L
• Format: Article
• Language: English
• Subjects: Applied fluid mechanics; Applied sciences; Biological and medical sciences; Biosensors; Biotechnology; Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; Fluid dynamics; Fluidics; Fundamental and applied biological sciences. Psychology; Fundamental areas of phenomenology (including applications); Mechanical engineering. Machine design; Methods. Procedures. Technologies; Physics; Precision engineering, watch making; Solid-fluid interfaces; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Various methods and equipments; Wetting
• ISSN: 0960-1317; 1361-6439
• DOI: 10.1088/0960-1317/17/1/N01

We present an in-plane nanotip incorporated into a microchannel at the tip of microcantilevers for the deposition of femtoliter droplets, thus addressing the miniaturization of biochips. The nanotip fabrication is based on anisotropic etching of Si by tetramethyl ammonium hydroxide with silicon nitride and local oxidation of silicon films as masking layers. This technique does not require high-resolution lithography nor an alignment technique. By using the obtained cantilever array with in-plane nanotips, matrices of water-glycerol droplets with a diameter of 2 mum and an interspot distance of 10 mum are achieved. It is demonstrated that the surface wettability of the nanotip and the substrate is an important factor influencing the droplet size.