Top-down technique
Toshitake Takahashi03/09/2009
EE235
• Demonstrate a new method to fabricate single fluidic-channel of uniform channel width (11-50nm) and over 1.5cm in length
• Imprint mold is created by unconventional nanofabrication (crystallographic anisotropic etching…)
Overview
(a) Innovative mold fabrication that creates a nanoimprint mold
(b) Use of the mold to imprint the nanochannel line in a functionalmaterial layer
(c) Optical RIE that transferres the imprinted patterns into a substrate
Schematic of fabrication steps for making imprint mold
Anisotropic wet etching with KOHAtomically smooth sidewall
• Conformal deposition of SiNxensure uniform channel width
• Channel width is defined by SiNx film thickness
SEM images of each step
Top-down SEM images of 17nm, 1.5cm long channel
• Uniform over the entirechannel• Offer sub-10nm lithographicresolution for patterningsub-20nm channel line
Channel continuity tests
(1) DI water containing fluorescent dye(2) DNA labeled with TOTO-1 fluorescent dye
(1) Flowing colored water (2) Flowing DNA in solution
Electrical conductance measurement
• With a salt solution, electrical conductance : Gm=66.1 nS• Electrical conductivity is σ=GmL/wd=10.2 S/m
Microchannel
Nanochannel
• Electrical conductance : Gm=0.40 pS• channel cross-section: 314 nm2
=(17.7 nm×17.7 nm)
Conclusion
• Demonstrate the fabrication of a single, narrow(as small as 11nm), long (over 1.5cm) and continuousfluidic channel
• This technique can be used for a variety of innovativebio/chemical sensors, particullary single-stranded DNAsequencing device