AVS 52nd International Symposium
    Nanometer-Scale Science and Technology Monday Sessions
       Session NS1-MoM

Paper NS1-MoM5
Three-Dimensional Nanochannels Formed by Oxide Deposition and Fast Etching of Polymer

Monday, October 31, 2005, 9:40 am, Room 204

Session: Nanometer Scale Structures
Presenter: C. Peng, University of Michigan-Ann Arbor
Authors: C. Peng, University of Michigan-Ann Arbor
S.W. Pang, University of Michigan-Ann Arbor
Correspondent: Click to Email
Nanochannels are widely used in biomedical applications such as DNA analysis and biomolecule detection. We report a method using sacrificial polymer and oxide to form three-dimensional (3D) nanochannels. Polymer nanostructures were patterned on Si substrates using optical lithography or nanoimprint lithography, followed by oxide deposition to form the sealed channels. A high-speed dry etching technique for removing the sacrificial polymer was developed using an oxygen plasma at high power, high pressure, and elevated temperature. This dry etching technique provides a fast lateral etch rate of 3.91 µm/min for the polymer inside nanochannels, which is an order higher than conventional reactive ion etching. High selectivity of 1200 is obtained between the lateral etch rate of polymer inside the nanochannels and the vertical etch rate of oxide. Etch rate dependence on pressure, temperature, and channel width were studied. It was found that the etch rate increases with pressure and temperature. To form multiple levels of nanochannels, the oxide covering the channels was planarized by a photoresist coating and etch-back process. After oxide planarization, the channel formation process is repeated and multiple levels of nanochannels can be stacked to build 3D nanostructures. A two-level nanochannel structure has been demonstrated and more complex 3D system is developed. Since oxide is transparent to visible light and the channels have hydrophilic surfaces, such 3D nanofluidic system is suitable for various biomedical studies.