Ultimate 3D e-beam lithography for nano/micro-structuring with NanoMaker

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Ultimate 3D e-beam lithography for
nano/micro-structuring with NanoMaker

• INTERFACE Ltd, Moscow
• IMT RAS, Chernogolovka, Moscow Region

rev. 2015
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Preview
The NanoMaker is a powerful lithography system
for electron and ion beam lithography using a
commercial SEM, FIB or dual beam microscope. The
NanoMaker solutions comprise modern Pattern
Generator hardware and versatile data preparation
software which allow both design and
nanofabrication. It provides friendly graphic
interface to create and design structures of
nano-size as little as 10 nm based on e-beam
lithography method for SEMs, make simulation of
resist exposure, calculate exposure dose
values/times in correlation with proximity effect
correction for 2D/3D structures, compensate
static distortion of e-beam deflecting system,
significantly reduce total exposure time by
reading and actively suppressing dynamic
distortion of e-beam deflection. NanoMaker system
is developed and launched as commercial product
by Interface Ltd. NanoMaker system is a result
of long and fruitful cooperation with a team of
scientists based on IMT RAS, Chernogolovka,
Moscow Region, Russia
Ultimate 3D e-beam lithography for
nano/micro-structuring with NanoMaker
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Goals
NanoMaker
Lithography systems
Families of Microscopes
JEOL Zeiss FEI Hitachi Tescan Leo Focused Ion
Beam and Dual Beam machines and others
The goal of NanoMaker is to achieve with a
conventional microscope maximum resolution
capacity in lithography mode. Practically it
means to convert a standard lab electron
microscope into a full-functionality e-beam
lithography system by fitting software and
hardware to control electron beam by compensating
dynamic and static errors of deflection system.
Just note that price for scanning electron
microscope starts from USD 100,000.00 and price
for full-functionality e-beam lithography system
starts from USD 1,000,000.00
Cost starts from USD1,000,000
Cost starts from USD 100,000
Ultimate 3D e-beam lithography for
nano/micro-structuring with NanoMaker
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NanoMaker purpose
NanoMaker is a unique complex, which facilitates
Scanning Electron Microscopes to obtain the
ultimate resolution and compensate inaccuracies
of microscope characteristics. It is developed

• to create and design structures of various
  geometry forms and of nano-size as little as 10
  nm to be exposed by e-beam lithography method
• to work with 2D and 3D structures in resist,
  create multilevel structures
• to overcome proximity effect appearing when
  micro- and nano- structures are exposed including
  2D and 3D structures
• to compensate static distortion of e-beam
  deflecting system by calculation methods
• to significantly reduce total exposure time by
  measuring and actively, on-the-fly,
  compensating dynamic errors of e-beam deflection

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NanoMaker purpose (continued)

• to simulate results of resist development by
  matching exposure dose and time parameters to
  provide 100 of known-good output
• to provide programmable control over
  cooperative movement of beam and stage, involving
  the blanking system as well
• to provide compatibility with other graphic
  software systems to import and export other known
  formats for images and support various types of
  SEMs, FIBs, lithographs, etc. equipment
• to support operations of scanning metrology
  microscopes and to work with fields, markers,
  video, etc.
• to provide image acquisition and carry out
  processing for fields alignment and stitching
• to work with large fields and provide seamless
  stitching of images

Some of the features are unique and are not
available in the market
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NanoMaker hardware
To provide capabilities of lithography systems
NanoMaker consists of two main parts Pattern
Generator and Software modules. Pattern Generator
is to control the exposure process by
sending/receiving signals to/from microscope as
it is sketched on the slide. Software modules are
intended to solve a number of tasks depending on
requirements to be mentioned further.
Pattern Generator
To control blanker
To control e-beam position
Image acquisition
To control stage
Ultimate 3D e-beam lithography for
nano/micro-structuring with NanoMaker
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NanoMaker hardware
Pattern Generator Elli30 PCIe Hardware comprises
two units analogue unit and digital
unit Analogue unit is a separate box with its own
stabilized power supply unit. Digital and
Analogue units are connected by two fiber optic
cables to provide high speed noise protective
data transfer. Digital unit is a PCIe Board
Controller.

• The Pattern Generator carries
• Two 16-bit Digital-to-Analogue Converters (50
  MHz DACs )
• One 8-bit Analogue-to-Digital Converter (ADC)
• Beam Blanker On/Off switch (TTL output level)
• Internal/External scan mode switch (TTL output
  level)
• Output XY DACs and input ADC signals can be tuned
  for arbitrary intervals in 10 V range.

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NanoMaker software
To provide capabilities of lithography system
NanoMaker provides integrated development
environment to create structures and design data
NanoMaker provides functions to control exposure
and stage operations.
NanoMaker provides functions to acquire markers
images, to recognize them and to write structures
under alignment control
NanoMaker provides functions to compensate
inaccuracies of microscope and improve
lithography yield, i.e.

• compensates distortion and dynamic errors
• calculates proximity effect correction
• makes simulation and predicts the results of
  exposure

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NanoMaker solutions
.
NanoMaker system can be supplied to the end user
in various combinations
NanoMaker-Full to create and design structures
of nano-size as little as 10 nm based on e-beam
lithography method for SEMs, make simulation of
resist exposure, calculate exposure dose
values/times in correlation with proximity
effect correction for 2D/3D structures,
compensate static distortion of e-beam deflecting
system, significantly reduce total exposure time
by reading and actively suppressing dynamic
distortion of e-beam deflection
NanoMaker-Editor is fully featured graphical
editor of lithographic structures with some
limitations of export possibilities in
unregistered version. Others functions can be
simulated for training purposes.
NanoMaker-Workbench module to design 2D and
3D structures, solve a problem of proximity
effect correction and to have output data in
formats (GDSII, DFX, ELM) acceptable by most
brands of existing lithographs. The inverse
transformation of data is also possible. It
means that data released in mentioned above
formats can be further corrected or re-designed
and exported back in the same format.
NanoMaker-Workbench allows to work in off-line
mode (without being directly connected to a
scanning microscope).

• NanoMaker-Writer combination of the
• Pattern Generator and software that allows to use
  a microscope
• for lithography tasks. It is this stage when
  conversion to lithograph is done
• and the best resolution to achieve proper
  lithography quality is possible.
• The main functions of the Pattern Generator and
  software are
• to control important microscope parameters
• to assign beam position (DAC),
• to control stage position
• to take image at the given location (ADC),
• to switch on/off the e-beam blanker

NanoMaker complete system fully solves the task
to convert scanning electronic microscope into
e-beam lithograph
NanoMaker-Full
NanoMaker-Workbench
NanoMaker-Writer
NanoMaker-Editor
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Interface Ltd. www.nanomaker.com
NanoMaker software modules diagram
Recommended Parameters Database
Postprocessing
Editor (Specialized 2D/3D CAD)


Negative, Union, Frame, Shrink, Erase,
Stratification, Overlaps out





Proximity Simulation
Proximity Effect Correction
Exposure Development Simulation
NanoMaker-Workbench
NanoMaker-Writer
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Practical implementations of modules
OFFLINE MODE
ONLINE MODE
Import of structures
NanoMaker-Writer
NanoMaker-Workbench
Data designing or redesigning
.DXF, .CSF, .GDS, .TIF, .BMP and
holograms with complex topography up to
100 Mgb
Export of data
Pattern Generator
Or transfer of structures
Designing own structures
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Unique features of NanoMaker
In the market of similar software unites
NanoMaker offers unique features Proximity
effect correction for 2D and 3D
structures Simulation of resist
development "Distortion compensation" -
compensation of static distortions of
deflection system Measurement and active
compensation of dynamic distortions of
deflection system and as a result
possibility to exposure without


beam blanker    Advantage
features for hologram/kinoform applications
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Proximity effect
Proximity effect correction is especially
important for closely packed, differently sized
pattern elements. Though it is applicable to
simple structures as well. The proximity effect
becomes apparent in small enough areas when
forward and backward scattering takes place in
the substrate and leads to overexposure, thus
resulting in breaking the accuracy of the
structure.
In the figure it is depicted an e-beam exposed
to a chip. The chip consists of substrate
covered with resist. Initially the e-beam was
focused. However when it permeates both-way
trough substrate and resist, electron scattering
takes place. As a result radiation dose is
disproportioned and final exposed area (?) is
significantly more than it was initially (?0)
assigned.

• This fact is depicted in the slide.
• The resulting radiation dose redistribution in
  resist
• is known as proximity function
• and has the following values of parameters
• ? - fractions of micron,
• ?0 hundredths of micron,
• - microns.
• The fact is the more e-beam energy the more
  disproportion is.
• The value of disproportion is as well subject to
• parameters of substrate and resist.
• To the convenience of the users NanoMaker
• offers its own integral database of Recommended
  Parameters.
• It enables to fast match assignments of
  parameters.

?0 e-beam width when reaching resist
? e-beam width when leaving resist. It defines
actually exposed area
? e-beam width when reaching substrate
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How Proximity effect works
Z
Simple exapmple to demonstarte the impact of
proximity effect
An elementary structure is shown. The total area
is about 20 micrometers. The structure resembles
field-effect transistor (FET). It consists of two
rectangulars and has a line of 0.2 micrometers
width. All gaps between elements are of the
similar width (0.2 micrometers). The circuit is
designed on Silicon chip with accelerating
voltage of 25 Kilo electro Volt.
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How Proximity effect impacts
If proximity effect is not corrected then the
result coud be depicted this way
Simulation
Photo of the exposed pattern
The fact the top line is missing is due to
insufficient radiation dose, contrary, excessive
dose resulted in gaps vanishing between
rectangular.
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How proximity effect is corrected
NanoMaker provides function to calculate the dose
distribution along the area.
Figure shows the areas depicted by isolines,
which highlight the zones with uniform
characteristics. In our case it means that each
zone has ascending dose from 105 up to 125
against 100 initial dose .  
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Result of proximity effect correction
After simulation shows satisfied results exposure
is done
100 of known-good output
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Simulation proximity effect and resist
development
One more unique feature of NanoMaker is
possibility to output the lithography image
simulated in the screen. It is possible to assign
and alter various dose/time parameters and then
follow it with preview in the screen as if resist
development has taken place. In the preceding
figures we can notice the coincidence with the
experimental data obtained. This way simulation
process effects in saving time and physical
resources. We have to note that resulting
accuracy of proximity effect correction is very
much subject to accuracy of assigned parameters.
Wrongly assigned, from accuracy point, parameters
can even increase distortion effect. That is why
NanoMaker maintains the database of Recommended
Parameters for most common types of substrate.  
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Sample of proximity effect correction for 3D
structure
Presently the problem to create 3D structure with
e-beam lithography, say for optical applications,
comes into consideration more and more often
Simulation ofeExposure dose. Iisolevels after
correction
Topographic expression of 3D structure
An AFM image of a relief of transparent polymer
DOE after copying from metal replica.
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Example of creating 3D structure
Kinoform optics
Using 3D proximity correction and electron
lithography, objectswith arbitrary 3D shape
could be created with single exposure session.
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Distortion compensation (static)
One of the significant NanoMaker function is
capability to compensate distortions, both static
distortion of deflection system and dynamic
distortion of e-beam long jump.
The static distortions arise from electromagnetic
lenses imperfection.
Ideal shape of scanning
Actual shape of canning
NanoMaker provides with a function to measure the
distortions of microscope operative field and
store the values of deviation from pattern grid.
These values are used for calculation of e-beam
trajectory to meet the parameters of a given
pattern grid.
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Distortion compensation (dynamic)
NanoMaker/Writer provides with one more
absolutely unique feature to measure and carry
out active compensation of dynamic distortions of
deflection system.

• NanoMaker solution
• No blanker system is required when structure is
  written in one field
• Compensate distortion by addressing to the
  trajectory resulting into ideal line

• Common solution
• Use blanker system
• Wait till e-beam is settled at the point

Result Waiting time usually exceeds pure exposure
time several times
Result Calculated exposure time is pure time of
total exposure process
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Example of distortion compensation
The structure with long jump of e-beam
No compensation
With compensation
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Alignment
This function enables to make lithography of
complex multi-layer structures. It enables

• acquire an image of existing lithography layers
  and recognize markers in automatic or
  semi-automatic mode
• rotate, zoom and shift the image
• align a new layer with existing objects of the
  image as per given markers
• make exposure in a new coordinate frame

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Alignment (example)
Here we will demonstrate how it works on the
samples prepared with the NanoMaker alignment
function.
In the figure shown gold contacts along with
markers were done with optical lithography tools.
With the help of NanoMaker the dimensions of gold
contacts were measured, depicted and aligned with
the given layers and whereupon they were pickled
in hetero-structure on GaAs.
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Alignment consequence
First optical lithography
With NanoMaker the dimensions of gold contacts
were measured, depicted and aligned with the
given layers and whereupon they were pickled in
hetero-structure on GaAs.
a)
c)
Placing metallic ferromagnetic material in the
places marked by cross lines.
d)
b)
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World market

• Nearest competitors
• The nearest competitors at the market are
• NPGS
• Raith GmbH
• We refer to the book Micro-lithography,
  Micromachining and Microfabrication (ed. P
  Rai-Choudhury),Volume1 Microlithography, Section
  2.5, written by M. McCord and M. Rooks. Web ref
  http//www.cnf.cornell.edu/cnf_spie54.html

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World market
Interface Ltd. JC Nabity Lithography Systems Raith GmbH
Functionality NanoMaker, Elli30 PCIe NPGS, ver. 9 Elphy-Plus or Elphy-Quantum
Proximity correction Yes No Yes
Development simulation Yes No Yes
3D structure editor Yes No No
Alignment Automated or manual Automated or manual Automated or manual
Stitching Automated, accuracy limited by stage Automated, accuracy limited by stage Automated, 0.1 um accuracy with laser stage
Energy 0-40 kV for typical SEM, but depends on target instrument 0-40 kV for typical SEM, but depends on target instrument 0-40 kV for typical SEM, but depends on target instrument
DAC speed Fast, 50 ns per exposure point (20 MHz) Mid-range, 0.2 us per exposure point (5 MHz) Mid-range, 0.16 us per exposure point (6 MHz) for Elphy-Plus
Stage Support for any automated stage Support for any automated stage optional laser controlled
Control computer PC compatible, PCIe bus, OS Windows PC compatible, PCI bus, OS Windows PC compatible, PCI bus (Elphy-Quantum), OS Windows
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Resume
NanoMaker is a commercial product that can be
customized as per customers requirements

• The main purpose of NanoMaker system is to
  convert conventional
• electron microscope into lithography system
• Successfully defined and solved Proximity Effect
  Correction problem
• for 2D and 3D structures that enables to
  fulfill designing and simulation
• Unique functions are developed and implemented
• Proximity effect correction for 3D structures
• Static distortion compensation
• Dynamic error correction

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Photo Gallery (Cantilever needle)
The examples of integration of NanoMaker into AFM
are shown at the slides as possibility to grow up
tips for cantilevers with high accuracy. Actually
this is an unique technique which is used for
industrial needs. The process is done in the
standard work chamber.
This technique is used in manufacturing
probes/sondes and calibration standard for
scanning sonde microscopy. NanoMaker enables to
grow up the tip of a standard silicon cone tip
and get tip with diameter of 100-200 nm and
length up to unites of micrometer.
Front
Side view
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Photo Gallery (Implementation for fun)
Nature Materials - published the photo to
illustrate macroscopic adhesive properties by
showing a spider-man toy clinging with one of its
hands to a horizontal glass plate. The toy (15 cm
high weighing 40 g) has its hand covered with
the microfabricated gecko tape, which provides a
0.5 cm2 contact with the glass and a carrying
capacity of gt100 g.
Imitation of gecko paws performed in lab with
JEOL - 840
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Photo Gallery (Nano World)
The smallest map of the world.
The width of line is 10 -20 nm
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Contacts

• We thank you for your attention
• Please visit our site www.nanomaker.com
• Contact us at e-mail sales_at_nanomaker.com