From Ink-Jet Technology to
Nano Array Writing
Technology
By
Szu-kang Hsien
Ayodeji Coker
OVERVIEW
Objective.
Approach.
Our Nano Array Writing Device.
Conclusion.
Acknowledgements.
OBJECTIVE
The use of nano-technology and
microfabrication techniques for nano array
writing.
Replacing conventional lithography methods
with nano array writing capable of producing
30nm line widths.
The independent control of each AFM tip
used in the nano-array writing technology
using comb-drive actuators.
APPROACH
Using the concept employed in Dip Pen
Nanolithography (DPN) for nano array
writing.
Using ink-jet technology as a mode of
delivering ink to an AFM tip capable of writing
line widths on the order of nano-meters.
Motion control in the x-y-z plane is done
using comb-drive and electrostatic actuators.
INK JET TECHNOLOGY
Drop On Demand (DOD) ink-jet printing is to
be utilized in our device.
A high voltage is to be applied to a PZT
crystal causing it to bend. This effect in turn
applies a pressure on the ink reservoir.
As a result of the applied pressure, the
reservoir jets out ink on demand, in our case
to coat the AFM tip.
Schematic of Ink delivery
structure
Ink Reservoir
piezoelectric material
Drive circuit
Ink
writing substrate
AFM tip
INK JET TECHNOLOGY
A change in voltage gives rise to a corresponding
change in force and the resulting dimensional
change in length.
V=dijFjx/(orA)
F will be 0.11 N using PZT film dimension
100m*100m, r=3000, d11=370 pC/N, d31=110
pC/N, V=10V and x = 2m.
The displacement of the crystal, L= LV/(td31),
will be around 0.2m.
So we can stack around 5 PZT crystals together
in order to have 1m pressing into the ink
DIP-PEN NANOLITHOGRAPHY
(DPN)
Old technique of dip pen
writing.
In place of the nib used
in the regular dip-pen,
an AFM tip is employed.
Using ink-jet technology,
“ink” is transported to
the AFM tip, which it
coats.
The ink is delivered to
the substrate, by
choosing an “ink” and
substrate that have an
affinity for one another
e.g ODT and Au.
AFM Tip
Writting Direction
Molecular Transport
Water Meniscus
Au Substrate
ATOMIC FORCE MICROSCOPE
(AFM)
AFM relies on a scanning technique to to
produce very high resolution 3-D images
of sample surfaces.
There are three methods used in AFM
applications. They are the contact mode,
the intermittent contact mode and the non
contact imaging.
The method employed NAWT is the
intermittent contact mode method.
Force vs. distance curve showing tip
sample Separation of different AFM
operating modes.
Schematic of AFM
x
z
Sample
y
Deflection
Sensor
Tip
xyz
Translator
Lever
Constant
F
COMB DRIVE AND
ELECTROSTATIC ACTUATORS
A large number of fine interdigiated
fingers are actuated by applying a
voltage between them.
This will provide the x-y motion for our
device.
The z-motion is achieved by
electrostatically actuating the cantilever
on which the AFM is attached.
Comb Drive Actuators
Our Nano Array Writing Device
Ink Jet Structure.
Scream Process for the fabrication of
the comb drive actuators.
AFM tip fabrication.
3-D image of our nano array writing
device.
Ink Jet Fabrication
(a)
p++ Si
PZT
Al Inte r co nne ct
(d)
Ink
Si
(b)
(e )
Flow
Chann e l
Ink
Ink Inle t
Or ifice
(c)
LPCV D SiO2
PZT
Ink
Noz z le
Ink Inle t
Or ifice
Persepective view
Scream Process
p h o to r e s is t
( a)
(e )
SiO2
Si
Ph o to lit h o g r ap h y
Re m o ve f lo o r Oxid e
(f)
(b)
Si
Se co n d Silico n e t ch
Pat t e r n T r an s f e r
( c)
(g)
De e p Si e t ch
SF6 Re le as e
(d)
PECV D SiO 2
Sid e w all Oxid e
d e p o s it io n
( PECV D)
(h)
M e t alliz at io n b y
s p u tt e r in g
AFM tip Fabrication
(c)
(a)
Saw Cut
Glas s
M as k ing m ate r ial (SiO
2)
Cr
Si
Bonding
(b)
(d)
s aw cut
Si3N4
Si3N4
Gl ass an d C r
r emoved
100 m
(e )
m e tal
fr e e cantile ve r
tip
3-D Structure Of Our Device
Comb Drive
Cantilever beam
AFM Tip
Ink channel
Electrode to control
Z
Drive Circuit
piezoelectric
material
Ink Reservoir
Conclusion
Technology is feasible.
NAWT is a faster way of doing
lithography.
Comb drive in Collaboration with
electrostatic cantilever deflection is a
good method of control in all 3
dimentions.
Acknowledgements.
Prof. Horacio Espinosa for his guidance
and advice.
Prof. Chad Mirkin for taking time to
provide us with all the necessary
information on DPN.
Zhu the TA for all the literature and
help he gave us.