Design and fabrication of a novel microfluidic nanoprobe

• Published in: Journal of microelectromechanical systems Vol. 15; no. 1; pp. 204 - 213
• Main Authors: Moldovan, N., Keun-Ho Kim, Espinosa, H.D.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.02.2006; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Applied fluid mechanics; Chips; Design engineering; Devices; Dip-pen nanolithography; Exact sciences and technology; Fabrication; Fluid dynamics; Fluidics; Fundamental areas of phenomenology (including applications); Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Mechanical instruments, equipment and techniques; Microchannel; Microfluidics; Micromachining; Micromechanical devices and systems; micropipette; Nanocomposites; Nanolithography; Nanomaterials; nanoprobe; Nanostructure; Oxidation; Physics; Reservoirs; Silicon; Silicon nitride; Testing; Writing; Bulk micromachining; micropipette; System on a chip; Dip pen lithography; Experimental study; nanoprobe; Sealing; Cantilever beam; Dip-pen nanolithography; Silicon nitrides; Surface micromachining; Oxidation; Microelectromechanical device; Electrochemical etching; Microfluidics; Sacrificial layer; Fluidics
• ISSN: 1057-7157; 1941-0158
• DOI: 10.1109/JMEMS.2005.863701

The design and fabrication of a novel microfluidic nanoprobe system are presented. The nanoprobe consists of cantilevered ultrasharp volcano-like tips, with microfluidic capabilities consisting of microchannels connected to an on-chip reservoir. The chip possesses additional connection capabilities to a remote reservoir. The fabrication uses standard surface micromachining techniques and materials. Bulk micromachining is employed for chip release. The microchannels are fabricated in silicon nitride by a new methodology, based on edge underetching of a sacrificial layer, bird's beak oxidation for mechanically closing the edges, and deposition of a sealing layer. The design and integration of various elements of the system and their fabrication are discussed. The system is conceived mainly to work as a "nanofountain pen", i.e., a continuously writing upgrade of the dip-pen nanolithography approach. Moreover, the new chip shows a much larger applicability area in fields such as electrochemical nanoprobes, nanoprobe-based etching, build-up tools for nanofabrication, or a probe for materials interactive analysis. Preliminary tests for writing and imaging with the new device were performed. These tests illustrate the capabilities of the new device and demonstrate possible directions for improvement.