Advanced
Scanning Probe Lithography
第五组 盛博文 刘杰 王倩 张存志 王士博
Outline
• Introduction
• Several Advanced SPL
• Outlook
Introduction
What is SPL
Why do we develop SPL?
How do we develop SPL
What is SPL
Schematic of scanning probe lithography
Ricardo Garcia. et al. Advanced scanning probe lithography. Nature nanotechnology. 10,1038(2014)
Full name:
scanning probe lithography
a kind of nanotechnology
So many methods to develop SPL, but they have
common thread which is the core of SPL
Classification of SPL
The process of the contact or near contact between the sharp
probe and the nanoscale region of the sample surface
The various methods that control the position of the scanning probe
relative to the underneath surface ,also the feedback mechanism of SPL
Classification of SPL methods according to the dominant tip–surface interaction
used for patterning, namely electrical, thermal, mechanical and diffusive processes
Ricardo Garcia. et al. Advanced scanning probe lithography. Nature nanotechnology. 10,1038(2014)
Why do we develop SPL
The physical limitation of conventional lithography reached
A single patterning run about 80nm
Conventional lithography
• The resolutions below 30 nm with EBL is difficult because of
proximity effects
Photolithography
electron beam lithography
Tennant, D. M. in Nanotechnology (ed. Timp, G.) Ch. 4, 161–205 (Springer, 1999).
The relationship between resolution and throughput in the advanced
scanning probe techniques
Martinez, R. V., Losilla, N. S., Martinez, J. & Garcia, R. Patterning polymeric structures with 2 nm resolution at
3 nm half pitch in ambient conditions. Nano Lett. 7, 1846–1850 (2007).
The advantages of SPL
compared with conventional lithography
• SPL is capable of patterning a large variety of materials
• Most of SPL writing processes are direct write
Just as single-step process
• Simplify the facilitates and save money
Lin, Y. C. et al. Graphene annealing: how clean can it be? Nano Lett. 12, 414–419 (2012).
Some striking examples of SPL’s wonderful capabilities
nanoribbon on graphene
Patterning of ferritin molecules
A nanoring inner
radius 160 nm, outer
radius 380 nm
Height image of
three trenches and
one bump
patterned on a
graphene
Weng, L., Zhang, L., Chen, Y. P. & Rokhinson, L. P. Atomic
force microscope local oxidation nanolithography of
Thermal and thermochemical SPL
thermal cantilever
comprising integrated joule
heaters for tip heating
利用悬臂梁尖端高温改变基底
物理、化学性质
Methods of heating
laser heating
resistively heated
热流传导
Four conduction
 Radiation一般可以忽略
 Air conduction有时可以很大，但是加热面积大，无法使基底产生高温
 Conduction through tip较多，并且热流集中，利于局部产生高温
application
880X880pixels
Less than 12 seconds
苯二醛基底
Reduced graphene oxide（tc-SPL）
处理后的区域导电性明显增强
电导率实现4个量级的调控
3D Greyscale patterning
Ricardo Garcia. et al. Advanced scanning probe lithography. Nature nanotechnology. 10,1038(2014)
Bias SPL(b-SPL)
• The small size of the AFM tip’s apex and the proximity of the
surface facilitates the generation of extremely high electrical
fields and, in conducting samples, a focused electron current.
• b-SPL experiments can be performed in ambient or liquid
environments, which, in turn, increases the number of
available chemical species.
Oxidation SPL
Oxidation SPL is based on the spatial confinement of an
anodic oxidation reaction between the tip and the sample
surface
oxidation process is mediated by the
a water bridge
General electrochemical reactions
in local anodic oxidation
The role of water and electric field
provides the oxyanions(含氧阴离子)
Water meniscus(液膜)
confines the reaction laterally, determines
the resolution（分辨率）
induces the formation of the water bridge
electric field
generates the oxyanions
drives the oxyanions to the sample
interface and facilitates the oxidation
process
Reasons for widespread academic use of o-SPL
1 the ability to nanopattern a wide variety of materials
2
minimal technological requirements(room temperature and atmospheric pressure)
3
performing many tasks concurrently
Application of Oxidation SPL—Molecular architectures
Typical example: pattern linear arrays of ferritin proteins
Main steps to pattern ferritin proteins
on a silicon surface
AFM image of an array of
ferritin molecules
Process illustration
1
functionalization of the silicon
surface
1
2
removes the self-assembled monolayer
in the regions exposed to the field
3
3
2
an APTES monolayer is deposited in the
patterned lines
4
ferritin deposited on the amino-terminated(氨基末端) regions of
the APTES patterns
4
Application of Oxidation SPL— Nanoelectronic devices
Typical example: silicon nanowire transistors
Scheme of the fabrication of a very thin and
narrow oxide mask
Atomic force microscopy images of
silicon nanowires
Application of Oxidation SPL— Nanoelectronic devices
Typical example : Nanoelectronic devices
Scheme of the fabrication of a graphene
quantum dot
Atomic force microscopy image of a
single quantum dot
Additional SPL methods
1. Nanomachining
2. Nanoscale dispensing
3. dip-pen nanolithography
Some examples
Mechanical SPL (nanomachining) uses the mechanical force exerted by the tip
to induce the selective removal of material from a surface .
Schematic of material removal using atomic force microscopy
Tseng, A. A. Removing material using atomic
force microscopy with single- and multiple-tip
sources. Small 7, 3409–3427 (2011).
Tseng, A. A.
Removing
material using
atomic force
microscopy with
single- and
multiple-tip
sources. Small 7,
3409–3427
(2011).
Biological protein patterning using AFM mechanical scratching: a) AFM image of a
scratched groove pattern with a typical groove depth of 7 nm and a mouth width of 300
nm. b) AFM image after sequential adsorption of an IgG protein and a fluorescently
labeled anti-IgG protein antibody. c) Fluorescence microscopy image of b. d) DGpp surface
being scratched by an AFM tip to expose the underlying HApp substrate. e)Scratched
surface incubated with a rabbit IgG protein solution. f) A fluorescently labeled anti-IgG
protein that selectively binds to the rabbit IgG molecules being incubated with the surface.
g) After rinsing, the immobilized protein remains on the exposed HApp scratched regions.
Tseng, A. A.
Removing
material
using
atomic
force
microscopy
with singleand
multiple-tip
sources.
Small 7,
3409–3427
(2011).
NiFe nanoconstriction made by AFM scratching: a) AFM images of a NiFe
planar nanowire after machining or scratching. b) Cross-sectional profiles
before and after machining. c) Current–voltage ( I – V ) characteristics of
nanoconstriction measured before and after machining
Outlook & Conclusion
 SPL in scientific research is established and
expanding, however more technological
applications still need to be fulfilled.
 The throughput is a main challenge before
application
 Some other challenges like parallelization
and tip lifetime are still to be resolved