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