WHITEPAPER – THREE-DIMENSIONAL LASER WRITING ON THE NANOMETER SCALE
Dipl.-Phys. Steffen Arnold

Three-Dimensional Laser Writing on the Nanometer Scale
Piezo Drives are Driving Technology Forward

Physik Instrumente (PI) GmbH & Co. KG_Auf der Roemerstrasse 1_76228 Karlsruhe, Germany
Tel. +49 721 4846-0, Fax +49 721 4846-1019 Email info@pi.ws, www.pi.ws

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WHITEPAPER – THREE-DIMENSIONAL LASER WRITING ON THE NANOMETER SCALE
Dipl.-Phys. Steffen Arnold

The

best

possiblepositioning

accuracyisnow

Many applications, especially those in the field of

mandatory in many fields of application. The examples

research and development, will benefit from the newstretch from the manufacture of semiconductors throughlithography system, which can be used to produce

biotechnology to optical metrology and microscopy.

reproducible structures on submicrometer scales fully

Nanopositioning systems with piezoelectric actuators

automatically and with a design flexibility not previously

are usually the devices of choice in such applications.

known.

They operate with repeatabilities in the nanometer range
with response times below a millisecond, are vacuumcompatible and work in a wide temperature range. Andso, they are opening up new fields of operation for theprecision positioning systems. New laser lithographysystems are a typical example.

Fig. 1 Novel laser lithography system from NanoscribeGmbH which – for the first time – allows the productionof complex three-dimensional microstructures andnanostructures using photo-sensitive materials (Image:Nanoscribe GmbH)
Nanoscribe GmbH, which was founded at the end of2007 in Eggenstein-Leopoldshafen, has launched a newlaser lithography system (Fig. 1) which, for the first time,allows the production of complex three-dimensional
microstructures and nanostructures using photosensitive
materials. More than seven years of research flowed into
thestart-upcompany,atboththeInstitutefor

Nanotechnology at the Karlsruhe Research Center(FZK) as well as at the Institute for Applied Physics at

Fig. 2 A matrix for cell biology produced with 3D
lithography (Image: Nanoscribe GmbH)
Typical fields of application for the new technology are,forinstance,

theproductionof

three-dimensional

matrices for cellular biology (Fig. 2), the manufacture ofmicro-optical components or photonic crystals (Fig. 3)
andalsomicrofluidic

asaandrapid-prototyping
nanofluidic

instrument

systems

andfortheir

production in small batches.
The desired structures can be designed and thenimported using any CAD software which supports theDXF format, or alternatively by using the speciallydeveloped script language GWL, which is speciallydesigned to meet the needs of 3D structuring.

the University of Karlsruhe (TH).

Physik Instrumente (PI) GmbH & Co. KG_Auf der Roemerstrasse 1_76228 Karlsruhe, Germany
Tel. +49 721 4846-0, Fax +49 721 4846-1019 Email info@pi.ws, www.pi.ws

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WHITEPAPER – THREE-DIMENSIONAL LASER WRITING ON THE NANOMETER SCALE
Dipl.-Phys. Steffen Arnold“This enables us to achieve very high quality results.
This positioning task is made all the more difficult by thefact that it is not sufficient to drive to specific positions
very accurately. The path here is just as important as
the destination, which means the application must also
have a precise trajectory control. During the journey, wecan then vary the laser intensity according to theacceleration or delay of the drive system in order toachieve the required lithography result.”

Fig. 3 Photonic crystal (Image: Nanoscribe GmbH)

Track widths down to 150 nm arepossible
The operating principle of the new lithography process,which is suitable for a large number of commerciallyavailable photoresists, is easily understood: Ultra-shortlaser pulses are strongly focused into the material,
which is thus exposed by means of a nonlinear opticalprocess in the focal point. Like a pen that is moved inthree dimensions, the laser beam writes on the material
following arbitrary paths. It is thus possible to achieve
track widths from several micrometers down to 150 nm.
Two-dimensional or 2½ D structurings are, of course,
also possible and have a resolution which is significantly
higher than that allowed by conventional systems up tonow.

Fig. 4 Martin Hermatschweiler, CEO of
Nanoscribe GmbH (Image: Nanoscribe GmbH)

Positioning System with Piezo Drive
and Parallel Motor Metrology for
Fine Adjustments
One of the key components for the demands is thus thepositioning system from Physik Instrumente (PI). PI
offers the largest selection of high-speed and high-High precision can only be achieved with three-resolution piezo nanopositioning system for scientificdimensional lithography if the corresponding accurate

and industrial applications in the world (Figure 5). “Thepositioning is possible, however. “During the writing

piezo stage can easily be mounted on the XY scannerprocess, both the laser and the focus remain fixed, thestage usually used with microscopes for the coarse

sample is moved according to the three-dimensional

adjustment (Figure 6). It operates with scanning ranges

writing task,” explains Martin Hermatschweiler (Fig. 4),

up to 300 × 300 × 300 µm³, and the repeatability is in the

CEO of Nanoscribe GmbH.

nanometer range,” Hermatschweiler is happy to explain.

Physik Instrumente (PI) GmbH & Co. KG_Auf der Roemerstrasse 1_76228 Karlsruhe, Germany
Tel. +49 721 4846-0, Fax +49 721 4846-1019 Email info@pi.ws, www.pi.ws

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WHITEPAPER – THREE-DIMENSIONAL LASER WRITING ON THE NANOMETER SCALE
Dipl.-Phys. Steffen Arnold

This means all piezo actuators act on a central platform.
And so all axes can be made to behave with identicaldynamics. This is particularly advantageous with 3D
lithography because the samples can have any type ofstructure.

One“slower”

axis,

which

would

beunproblematic for a linear scan, for example, would havedetrimental effects here. Moreover, the sensorics
register all closed-loop controlled degrees of freedom
simultaneously. This parallel

metrology makes it

possible to actively prevent axis crosstalk and lateralFig. 5 The high-speed and high-resolution piezo
nanopositioning systems are suitable for a wide varietyof scientific and industrial applications (Image: PI)

runout.

Thisbenefits

thetrackaccuracyandreproducibility.

The high-precision capacitive sensors integrated into thepositioning system ensure the accurate actual value
measurement which is required to move the sample with
precision below the laser is achieved. They record themotion directly and thus make it possible to have higher
phase fidelity and bandwidth than indirect systems.

Fig. 7 The controller card is constructed as a PCI board
and is specially matched to the control of multi-axis
piezo nanopositioning systems (Image: PI)The trajectory control required here is carried out by aFig. 6 The fine adjustment of object or sample is carriedout by the piezo nanopositioning system, which not onlyoperates with high accuracy but can also be readily
integrated into the application (Image: PI / NanoscribeGmbH)The way it is constructed as a parallel kinematics multi-digital controller constructed as a PCI board. Both thenanopositioning system and the PCI board come fromthe PI program and the former is specially matched tothe multi-axis parallel kinematics piezo nanopositioningsystems.

axis system also contributes to the high positioning“It is even possible to meet the very high demands

accuracy

thewhich our 3D lithography systems make on the track

becausethedriving

forceofsystems are preloaded, extremelyaccuracy” adds Hermatschweiler. The highly accurate

durable high-performance piezo actuators, which arepiezo nanopositioning systems have thus made a

integrated into a friction-free parallel kinematics guiding

significant contribution to driving lithography technology

system with FEM optimized flexures.

a decisive step forward.

nanopositioning

Physik Instrumente (PI) GmbH & Co. KG_Auf der Roemerstrasse 1_76228 Karlsruhe, Germany
Tel. +49 721 4846-0, Fax +49 721 4846-1019 Email info@pi.ws, www.pi.ws

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WHITEPAPER – THREE-DIMENSIONAL LASER WRITING ON THE NANOMETER SCALE
Dipl.-Phys. Steffen Arnold

Piezo Actuators – High Accuracyand Dynamics

About the PI Group

Piezo actuators are the driving force behind the highspeed parallel kinematics nanopositioning systems usedin the new 3D lithography systems for the finepositioning of the objects or samples. These piezoactuatorsconvertelectricalenergydirectly

intomechanical energy and vice versa. Travel ranges of up
to one millimeter can typically be achieved with

Over the last four decades, PI (Physik Instrumente) with
headquarters in Karlsruhe, Germany, has developed
into the leading manufacturer of positioning systems
with accuracies in the range of only a few nanometers.
With four company sites in Germany and ten sales andservice offices abroad, the privately managed company
operates globally.

resolutions down to the nanometer range, and highMore than 700 highly qualified employees all over thedynamics with frequencies of up to several kilohertz areworld enable the PI Group to fulfill almost any

also achievable. The motion is based on crystalline

requirement from the area of innovative precisioneffects and so there are no rotating parts or friction;

positioning

piezo actuators are therefore maintenance-free and non-developed in-house. This allows the company to control

wearing, and because no lubrication is required, they

every step of the process, from design right down toare suitable for use in a vacuum. They can move large

shipment: precision mechanics and electronics as wellloads and have a very compact design.

as position sensors.

technology.

Allkeytechnologies

areThe required piezoceramic elements are manufactured

Authorby our subsidiary PI Ceramic in Lederhose, Germany,

Dipl.-Phys. Steffen Arnold, Head of Marketing &one of the global leaders for piezo actuator and sensor

Products at PI (Physik Instrumente) GmbH & Co. KG

products. The PI miCos GmbH in Eschbach near
Freiburg, Germany, is a specialist for positioning
systems for ultrahigh vacuum applications and parallel-About Nanoscribe
Nanoscribe GmbH, the first spin-off of Karlsruhe Instituteof Technology (KIT) introduced the 3D laser lithography

kinematic positioning systems with six degrees offreedom and custom-made designs.

system PhotonicProfessional on the market in early
2008. Over the last five years, the company has
established itself as market and technology leader in thearea of 3D laser lithography. The multitude of systems
sold to leading research institutes and universities
across the world demonstrates the triumph of thisinnovative technology. The portfolio of the company
additionallycomprisesin-housedevelopedresists

tailored to the different needs of customers. The portfolio
is completed by consultation on reproducing thesethree-dimensional polymer structures in metals orsemiconductors.

Physik Instrumente (PI) GmbH & Co. KG_Auf der Roemerstrasse 1_76228 Karlsruhe, Germany
Tel. +49 721 4846-0, Fax +49 721 4846-1019 Email info@pi.ws, www.pi.ws

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