Fabrication of 20 nm embedded longitudinal nanochannels by etching sacrificial nanowires
D. S. Choi and E. H. Yang
Jet Propulsion Laboratory, US
Keywords: nanochannels, sacrificial etching, FIB
The traditional electron beam lithography and more recently developed focused ion beam (FIB) milling/lithography techniques have been exploited for generating exposed nanometer-size nanochannels. An additional process step of sealing exposed nanochannels can't be avoided to generate complete nanodevices. Currently, sealing techniques such as wafer bonding and soft elastomer sealing are being used for sealing micrometer-scale exposed channels. However, current wafer bonding requires defect free and flat surface, and elastomer sealing process comes with clogging because of soft material intrusion into the channels. Our proposed technique provides a wafer bonding-free process to fabricate embedded nanochannels. In this abstract we describe a technique for fabricating nanometer-scale channels embedded by dielectric materials. Longitudinal "embedded" nanochannels with an opening size 20 nm x 80 nm have been successfully fabricated on silicon wafer by transferring sacrificial nanowire structures.
Longitudinal nanometer-scale embedded channels has been fabricated by a sacrificial nanowire etching technique. In our fabrication, an array of nanometer-scale metal nanowire patterns was first fabricated on SiO2/silicon wafer using FIB lithography and a subsequent metalization/lift-off process. The metal nanowire patterns were transferred onto SiO2 layer by reactive ion etching (RIE). Plasma Enhanced Chemical Vapor Deposition (PECVD) dielectrics were deposited on the SiO2 nanowire patterns. FIB milling was used to generate trenches both front region and rear region of the nanowires. Those trenches provided openings through which etchant chemicals (BOE) were going. As a result of a different etch rate of SiO2 and dielectrics in BOE, "embedded" nanochannel patterns were fabricated on silicon substrates. In order to reveal that channels were gone through two openings, FIB milling was used for a fast and precise analysis. Five various lengths (3, 6, 8, 10, 20 mm) of pillar patterns were tried to find a maximum length of enclosed channels which could be generated without experiencing "diffusion-blocking" during a sacrificial pillar etching process. 3 mm long longitudinal nanochannels were successfully fabricated. Those nanochannels can be used for the manipulation and analysis of biomolecules such as DNA and proteins at single molecule resolution.
NSTI Nanotech 2003 Conference Technical Program Abstract