Surface micromachined glass and polysilicon microchannels using MUMPs for BioMEMS applications

MUMPs (Multi-User MEMS Process) based microchannels made of either glass or polysilicon have been successfully designed, fabricated and tested. The fabrication process used timed wet-chemical etching to selectively etch sacrificial materials with the assistance of etch holes. The prototype glass and polysilicon microchannels have cross-section areas of 70 mum x 4 mum and 70 mum x 2 mum, respectively, and both microchannels have been tested to transport and contain water by means of surface tension. A simplified surface tension analysis shows that the height of the etch holes and the surface tension of the working liquid inside the microchannel dominates the pressure difference that holds the liquid from leaking outside the microchannel via etch holes. Because these rnicrochannels are fabricated using the foundry-based micromachining process, they present opportunities for economical prototyping and have great potential for integration with other microfluidic devices for system-level applications, such as DNA chip and lab-on-a-chip. (C) 2003 Elsevier B.V. All rights reserved.