Ultimate 3D e-beam lithography for nano/micro-structuring with NanoMaker INTERFACE Ltd, Moscow IMT...

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

NanoMaker

INTERFACE Ltd, Moscow

IMT RAS, Chernogolovka, Moscow Region

2007

2Ultimate 3D e-beam lithography for nano/micro-structuring with NanoMaker

NanoMaker - innovative solution for nano-lithography

NanoMaker is a hardware/software system and is intended for nanotechnologies. 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

Preview

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


NanoMakerSEMs Family

Lithography systems

JEOLPHILIPSZEISSLEICALEOHitachiTescanFocused Ion BeamMachinesZRM-20STM/AFM’s -(scanning probe microscopes)

Cost starts from USD 100,000

Cost starts from USD1,000,000


The goal of NanoMaker is to “extract” from a standard electronic microscope maximum resolution capacity in lithography mode. Practically it means to convert a standard lab electronic microscope into a full-functionality e-beam lithography system by fitting software to compensate dynamic and static distortion and hardware to control e-beam.

Just note that price for scanning electronic microscope starts from USD 100,000.00 and price for full-functionality e-beam lithography system starts from USD 1,000,000.00.

Goals


NanoMaker purpose

NanoMaker is a unique complex, which facilitates Scanning Electronic Microscopes to obtain the ultimate resolution and compensate inaccuracies of microscope charachteristics

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 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 reading and actively, “on-the-fly”,

suppressing dynamic distortion of e-beam deflection

- to work with 2D and 3D structures in resist, create multilevel structures

- to work with non-standard elements such as sone plates, kinoforms, hologramms etc.


NanoMaker purpose (continued)

- to simulate the results of resist exposure by matching exposure dose and time parameters to provide 100% of known-good output

- to provide programmable control over e-beam move, blanking system, stage etc.

- to provide compatibility with other graphic software systems to import and export other known formats for images and support various types of SEMs, AFM/SPM , ZRM etc. equipment

- to support operations of scanning metrology microscopes and to work with fields, markers, video, rotations etc.

- to provide image acquisition and carry out postprocessing with image adjustment and alignment

- to work with large fields and provide seamless stitching of images

Some of the features are unique and are not available in the market


NanoMaker hardware To provide capabilities of lithography systems


Pattern Generator

NanoMaker consists of two main parts: Pattern Generator Board and Software modules. Pattern Generator Board is to control the exposure process by assigning physical parameters as it is sketched in the slide. Software modules are intended to solve a number of tasks depending on requirements to be mentioned further.

Image acquisition

To control blanker

To control stage

To control e-beam position


NanoMaker hardware

Pattern Generator with PC Board Controller

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 fiber optic cable to provide high speed noise protective data transfer.

Digital unit is a PC Board Controller.

Pattern Generator board provides:

Two 16-bit Digital-to-Analogue Converters (DACs) (60ns Settling Time)

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 voltages can be tuned for arbitrary intervals in ±10.0 V range.


NanoMaker software To provide capabilities of lithography systems

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 foreign images and insert additional structures under alignment control

NanoMaker provides functions to compensate inaccuracies of microscope and improve lithography yield , i.e. :

•compensates distortion and dynamic delays

• calculates proximity effect correction

•makes simulation and predicts the results of exposure


NanoMaker solution

NanoMaker system can be supplied to the end user in various combinations:

NanoMaker/Full

NanoMaker complete system

fully solves the task to convert

scanning electronic microscope

into e-beam lithograph

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/Workbench

NanoMaker/Writer

NanoMaker/Lite

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.

Inversion 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 has a friendly interface and can work both in online

and off-line mode (without being directly connected to

a scanning microscope).

NanoMaker/Writer + Pattern Generator Board combination

enables to control scanning electronic microscope

or lithograph parameters with the help of Generator.

It is this stage when conversion to lithograph is done

and the best resolution

to achieve proper lithograph quality is “extracted”.

The functions of Pattern Generator Board are elementary.

That is to assign e-beam location (DAC),

to take the image at the given location (ADC),

and to switch on/off blank e-beam

NanoMaker/Editor – demoversion of NanoMaker to introduce the basic functions

.


NanoMaker software modules diagram

Proximity & Simulation

Proximity Effect Correction Exposure & Development Simulation

· Editor (Specialized 2D/3D CAD)

·

-Design of (hierarchical / multilayered ) structure-Load / Save Graphical Data Base (GDB) files-Import/Export GDS, DXF, ELM formats ·

Stage Control

-Stage Driver

Exposure (Writing )

With Alignment&Compensation for Dynamic/Distortion Errors

SEM inaccuracies characterization for active compensation

-Dynamic ( definition of dynamic delay )-Distortion ( definition of SEM optical system distortion )

·

Alignment & Adjustment (Working with Video)

-Scan Field Alignment Using Test Pattern or Stage-Stage Adjustment to Test Pattern or to Scan Field-Image Acquisition

Recommended Parameters Database

NanoMaker/Workbench NanoMaker/Writer

Interface Ltd. www.nanomaker.com

Postprocessing

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

Pattern Generator Board


Practical implementations of modules

Import of structures *.DXF,

*.CSF,

*.GDS,

*.TIF,

*.BMP and

holograms with complex topography up to 100 Mgb

Data designing or redesigning

NanoMaker/Workbench

Designing own structures

OFFLINE MODE

*.DFX, *.CSF, *.GDS

Export of data

NanoMaker/Writer

ONLINE MODE

Or transfer of structures

PG


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 proximity effect and resist development

"Distortion compensation" - compensation of static distortions of deflection system

Measurement and active countermeasures of dynamic distortions of deflection system and as a result – possibility to exposure without

beam blanker

Advantage features for hologram/kinoform applications


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.

0 – e-beam width when reaching resist

– e-beam width when reaching substrate

– e-beam width when leaving resist. It defines actually exposed area

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.


How Proximity effect worksZ

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.


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.


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 .


Result of proximity effect correctin

After simulation shows satisfied results exposure is done

100% of known-good output


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.


Sample of proximity effect correction for 3D structure

Simulation ofeExposure dose.Iisolevels after correction

An AFM image of a relief of transparent polymer DOE after copying from metal replica.

Presently the problem to create 3D structure with e-beam lithography, say for optical applications, comes into consideration more and more often

Topographic expression of 3D structure


Example of creating 3D structure

Using 3D proximity correction and electron lithography, objectswith arbitrary 3D shape could be created with single exposure session.

Kinoform optics


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.

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.

Ideal shape of scanning

Actual shape of canning


Distortion compensation (dynamic)

NanoMaker/Writer provides with one more absolutely unique feature to measure and carry out active countermeasures of dynamic distortions of deflection system.

Common solution

-Use blanker system

-Wait till e-beam is settled at the point

Result

Waiting time usually exceeds pure exposure time several times

NanoMaker solution

-No blanker system is required

- Compensate distortion by addressing to the trajectory resulting into ideal line

Result

Calculated exposure time is pure time of total exposure process


Example of distortion compensation

The structure with long jump of e-beam

No compensation With compensation


Alignment

This function enables to make lithography of complex multi-layer structures.

It enables:

- to read and acquire the existing lithography image

- make exposure in a new coordinate frame

- rotate and compress/stretch the image

- align a new lay with existing objects of the image as per given markers


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.


Alignment consequence

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.

First optical lithography

Placing metallic ferromagnetic material in the places marked by cross lines.

a)

b)

c)

d)


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


World market

Interface Ltd. JC Nabity *** Lithography Systems

Raith GmbH Leica Lithography Systems Ltd.

Functionality NanoMaker NPGS Elphy-Plus EBL Nanowriter

Proximity correction Yes No Yes No

Development simulation Yes No Yes No

3D**** structure editor Yes No No No

Alignment ** Automated or manual Automated or manual Automated or manual Automated

Stitching Automated, accuracy limited by stage

Automated, accuracy limited by stage

Automated, 0,1 um accuracy with laser stage

Automated, 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

10 to 100 kV

DAC speed Mid-range, 1us per exposure point (1 MHz)

Low, 10 us per exposure point (100 kHz)

Mid-range, 0.4 us per exposure point (2.6 MHz)

Mid-range, 1us per exposure point (1 MHz)

Throughput ** limited by DAC speed, PC performace, not with scan coils

Settling time of scan coils, transmission rate of ISA bus

Settling time of scan coils Settling time of scan coils

Stage Support for any automated stage

Support for any automated stage

optional laser controlled optional laser controlled

Control computer PC compatible

ISA|PC bus DOS/Windows

PC compatible

ISA|PC bus DOS/Windows

PC compatible

DOS/Windows

PC compatible


Resume

•The main purpose of NanoMaker system is to convert standard electronic 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 delay correction

NanoMaker – is a commercial product that can be customized as per customer’s requirements


Future projects

- To extend functionalities for Atomic Force Microscopes

- To provide a bridge between big machines to create dies and SEMs to replicate


Photo Gallery (Cantilever needle)

Front Side view

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.


Photo Gallery (Implementation for fun)

Imitation of gecko paws performed in lab with JEOL - 840

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 >100 g.


Photo Gallery (Nano World)

The width of line is 10 -20 nm

The smallest map of the world.


Contacts

We thank you for your attention

Please visit our site www.nanomaker.com

Contact us at e-mail: [email protected] or [email protected]

Ultimate 3D e-beam lithography for nano/micro-structuring with NanoMaker INTERFACE Ltd, Moscow IMT...

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