23-Nanoscribe GmbH - Booklet

20
True 3D Laser Lithography 2 µm

Transcript of 23-Nanoscribe GmbH - Booklet

Page 1: 23-Nanoscribe GmbH - Booklet

True 3D Laser Lithography

2 µm

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Company Background

Nanoscribe is a research spin-off of the Karlsruhe

Institute of Technology (KIT), the merger of the

University of Karlsruhe (TH) and the Forschun-

gszentrum Karlsruhe GmbH (National Labora-

tory of the Helmholtz Association).

The company was founded in 2007 by lead-

ing scientists in the field of photonic crystals

and metamaterials. A close interdisciplinary

collaboration with scientists both in Karlsruhe

and internationally provides the basis for fore-

front technical developments specially designed

for the needs of researchers. In 2008, following

a close collaboration, Carl Zeiss AG invested into

this innovative technology, now holding 40% of

the company’s shares.

Company Philosophy

Nanoscribe is set on transferring cutting-edge

technology to versatile and user-friendly systems

for three-dimensional (3D) nano- and microfabri-

cation. We pay particular attention to the needs

of our customers: Nanoscribe cultivates intense

connections with customers, partners and com-

ponent suppliers to develop the best solution for

your application.

We assure highest quality and fast cycles of inno-

vation, expanding our market leadership and

technological leadership in 3D laser lithography.

Contact Persons

Please feel invited to contact us in case of any

questions or inquiries.

» Martin Hermatschweiler (CEO)

management, finance, press

» Dr. Georg von Freymann (CTO)

technology, production, teaching

» Steffen Holtwick (CMO)

sales, marketing

» Dr. Holger Fischer

engineering, service

Com

pany

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True 3D Laser Lithography Systems

Nanoscribe develops and manufactures compact

and easy to operate laser lithography systems,

allowing for true 3D micro- and nanostructures

in various commercially available photoresists.

Applications are, e.g., in photonics, micro-optics,

micro-fluidics and life sciences.

Our unique technology is specially designed for …

» … true 3D micro- and nanostructuring

» … ultra-precise fabrication with feature sizes

ranging down to 100 nm

» … compact, comfortable and easy to use laser

lithography systems

Fabrication of Custom-Built Structures

Nanoscribe manufactures samples at cus-

tomer order and compiles custom designs for

specific structures. These samples comprise, e.g.,

photonic crystals as well as artificial extra-cellular

matrices for various experiments in life sciences.

Advanced Photoresists

Nanoscribe conducts intensive research and

development on novel photoresists for 2D and

3D lithographic applications. Complete photo-

resist systems comprising samples and appro-

priate developers or etchants are provided.

Casting and Coating

Nanoscribe has in-depth knowledge of a broad

bandwidth of casting and coating processes, e.g.,

single and double inversion of polymer struc-

tures into dielectrics as well as metals. We offer

expert advice on the implementation of custom-

ized installations.

Portfolio

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Basic Principles of Direct Laser Writing

The technique of direct laser writing allows for

the fabrication of almost arbitrary 3D nanostruc-

tures in suitable photoresists. It is based on multi-

photon polymerization, a non-linear optical effect.

The center wavelength of the laser is chosen so

that the photoresist is transparent since the one-

photon energy lies well below the absorption

edge of the material. By tightly focusing the light

of an ultra-short pulsed laser, the intensity within

the very focus is sufficiently high to expose the

photoresist by multi-photon absorption. This

process causes a chemical and / or physical

change of the photoresist within a small volume

pixel (“voxel”) that can be scaled by the laser

power.

This voxel typically is of ellipsoidal shape and is

the basic building block for the fabrication of

3D structures. By moving the sample relative to

the fixed focal position, arbitrary paths can be

written into the material. You can consider this

like using a nanometer-sized pen that draws in

three dimensions.

Tech

nol

ogy

The movement of the sample and the adjust-

ment of the laser intensity are synchronized by

a computer. Later on, the material change due to

exposure to the laser light and potentially a sub-

sequent thermal treatment leads to a chemical

selectivity between unexposed and exposed

volumes inside a developer bath. Depending on

the photoresist, either exposed (positive-tone

resist) or unexposed regions (negative-tone

resist) are removed.

The advantages of multi-photon polymerization

are evident:

» Ability to structure truly three-dimensional, no

matter how complex your structure may be.

» Superior resolution due to the non-linear

response of the photoresists.

» Flexibility: The ability to structure truly 3D

implies also the special, simplified cases of

planar structuring (2D) or complex surface

topologies that are suited for mass fabrication

via pattern transfer technique (2½ D).

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Technolog

y

Sample Fabrication Procedure

The course of sample fabrication is simple:

Blanks are usually produced by spin coating of a

photoresist onto a glass substrate and subse-

quent mounting in matched substrate holders

which are again inserted into the lithography

system. The desired structures are typically

programmed in a specialized general writing

language (GWL) that is well adapted for 3D struc-

tures. Alternatively, the structure data is imported

from common CAD data format (DXF) or a stereo

lithography file (STL). The system visualizes the

loaded structure data, automatically approaches

the designated sample and adjusts the focus

to the interface. By command the lithography

system exposes the sample. The system is capa-

ble of automatically processing multiple samples

in succession. Finally, the samples are developed

and post-processed.

In mathematics and physics, the dimension of a space or object is informally defined as the minimum number of coor-dinates needed to specify each point within it. Thus an array of lines has a dimension of 2 (2 D) since two coordinates are needed to specify a point on it. 2½ D is the construction of a 3 D environment from 2 D reti-nal projections. 2½ D

2½ D

2D

3D

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Phot

onic

Pro

fess

iona

l

PhotonicProfessionalTrue 3D Laser Lithography System

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Photonic Professional

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Phot

onic

Pro

fess

iona

l

Autofocus

A unique feature of Nanoscribe’s laser litho-

graphy systems is an autofocus. Due to patented

technology, the interface between substrate and

photoresist is determined exactly and autono-

mously. This establishes the basis for reliable

anchoring of your structures to the substrate—

may these structures be 2D or 3D.

The lithography systems automatically approach

the focusing objectives to the blanks and adjust

the focus to a designated elevation in reference

to the interface. Based on this unique techno-

logy, the lithography systems also offer a fully

automated substrate tilt measurement and

correction feature.

A motorized scanning stage combined with the

autofocus system and tilt correction allows for

the automated fabrication of large-area struc-

tures on numerous samples in a row.

PerfectShape™

PerfectShape™ is a routine of our control soft-

ware NanoWrite (see also page 9), automatically

adjusting the laser power with respect to the

actual writing speed while preventing over- or

underexposure of the resist in the case of varying

writing speeds (e.g., at the beginning and the end

of lines or during sharp turns). It also ensures a high

positioning accuracy along the writing path,

where sharp corners and bends may appear (see

images below).

Basic Features

The Nanoscribe 3D laser lithography system

“Photonic Professional” is designed for true 3D

micro- and nanostructuring of photosensitive

media, e.g., organic photoresists (like SU-8, IP-L,

IP-G), hybrid materials (ormocere) or the amor-

phous semiconductor As2S

3—materials which

are capable of two-photon polymerization.

PerfectShape™ OFF

PerfectShape™ ON

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Photonic Professional

NanoWrite

One of the key features of Nanoscribe’s laser

lithography systems is the user-friendly software.

A functional and intuitive user interface consid-

erably simplifies the realization of your structure

design. The software provides easy access to all

adjustable features of the lithography system.

NanoWrite has the ability to load GWL files (script

language developed by Nanoscribe to define

the writing of 3D structures, specialized on the

writing tasks in two and three dimensions) and

to import CAD data from common DXF files as

well as stereo lithography files (STL). The user

interface provides a visualization of the structure

data as well as a live camera view of the sample.

DeScribe

DeScribe is our GWL script editor which helps to

build command lists for the NanoWrite software.

Its main features are:

» GWL syntax highlighting

» Well-arranged list of all GWL commands

» Completion proposal

» Add code with help comments

» Text comparison (e.g., old script file and

recently updated script)

» Bookmarking

» Advanced text search and replacement

» Simple inclusions of pre-defined

template files

» Open files via drag-and-drop and via an

internal file explorer

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Phot

onic

Pro

fess

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l

-500 0 500lateral (nm)

600

400

200

0

-200

-400

-600

axia

l (n

m)

Isointensity curves by using an SRF

-500 0 500lateral (nm)

600

400

200

0

-200

-400

-600

axia

l (n

m)

Isointensity curves without SRF

x (nm)y (nm)

z (n

m)

500

0

-500200

0-200

2000

-200 x (nm)y (nm)

z (n

m)

500

0

-500200

0-200

2000

-200

The basic building block geometry (“voxel”) by using an SRF

The basic building block geometry (“voxel”) without SRF

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Photonic Professional

Options

Besides the aforementioned standard compo-

nents and features of Nanoscribe’s Photonic

Professional system, we offer the following

additional options which can be adapted to your

specific needs.

Shaded-Ring Filter

Nanoscribe’s shaded-ring filters (SRFs) are spe-

cially designed to achieve a maximal resolu-

tion in three dimensions. The axial resolution

is increased by more than 28% with respect to

operation without this special optic. This com-

ponent is essential if you intend to work at the

physical boundaries of photolithography.

Positioning Systems

In addition to the piezo-electrical scanning stage

and the manual stage, further positioning solu-

tions are available. A motorized scanning stage

with a travel range of 130 mm by 100 mm is

fully controllable via the software and allows for

laterally stitching together neighboring writing

volumes of the piezo to large sample areas as

well as direct writing by moving the motorized

scanning stage which is especially favorable for

large-scale microstructuring. Additionally, con-

secutive and automated processing of multiple

samples is possible.

Substrate Holders

Nanoscribe offers several specially designed sub-

strate holders. The most established version is a

holder for 10 round cover slips with 30 mm diam-

eter. Individual designs for particular substrates

can easily be implemented for dimensions of up

to 125 x 125 x 3 mm3.

Objectives

The microscope possesses an automated objec-

tive revolver that is controlled by the software.

A variety of oil immersion and air objectives are

available. Depending on feature sizes, processing

speed, and substrate properties, your lithography

system is tooled up with dedicated objectives.

Coupling of External Lasers

If you already have a suitable femtosecond-laser,

the lithography system can be adapted to be

operated with this external light source. Please

contact us regarding the eligibility of your laser.

Vibration Isolating Tables

We strongly recommend operating the system

on a vibration isolated table. Suitable optical

tables can be obtained from us on request.

Auxiliary Equipment

Auxiliary equipment for the sample preparation

(spin coater, hot plate, developer glassware) as

well as measuring tools (e.g., to determine the

sample thickness) can also be provided by Nano-

scribe. We are glad to assist you in order to make

your entrance into the third nano-dimension as

smooth and comfortable as possible.

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Are

as o

f A

pplic

atio

n Areas of Application

The advantages of multi-photon polymeriza-

tion recommend our systems not only the ideal

candidate for highly specialized tasks, but also

an excellent generalist for manifold demands

and activities, e.g., in instrument pools of nano-

fabrication centers. This versatility is also

reflected in the field of applications.

Most prominently one can find our systems

actively in operation in following research areas:

» Photonics

photonic crystals, metamaterials, diffractive

optics, distributed feedback lasers, photonic

ring resonators

» Micro Optics

micro optical devices, integrated optics

» Micro Fluidics

lab-on-a-chip systems, development of

substances, analysis

» Life Sciences

cell migration / stem cell differentiation / cell

growth studies, tissue engineering

» Nano- and Microtechnology

mask manufacturing, examination of Gecko

and Lotus effect

10 µm

10 µm

Courtesy of F. Klein, T. Striebel, and M. Bastmeyer, KIT (Germany)

Courtesy of T. Striebel and M. Bastmeyer, KIT (Germany)

Courtesy of F. Klein and M. Bastmeyer, KIT (Germany)

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Areas of A

pplication

10 µm

See also: M. Thiel et al., Adv. Mater. 21, 4680 (2009)

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1. IP-L and IP-G

Nanoscribe’s family of IPx photoresists is

specifically designed for the demands of true 3D

laser lithography by two-photon polymerization:

Extraordinary resolution in three dimensions

combined with high mechanical stability. Both

formulations available (IP-L, IP-G) are acrylic-

based negative-tone resists—ideal candidates,

e.g., in the field of photonics.

Basic Features:

» Feature sizes smaller than 100 nm

» Low proximity effect

» Low stress

» Little shrinkage

» Good adhesion on glass substrates

» Easy handling:

drop-casting of the photoresist

no pre-bake (IP-L)

no post-exposure bake (IP-L, IP-G)

Phot

ores

ists Applicable Photoresists

Nanoscribe continuously evaluates and develops

photoresists for 2D and 3D applications. Listed in

the following is a series of standard resists either

commercially available from Nanoscribe or other

suppliers. Please consult us to identify the photo-

resist best fitting your requirements.

10 µm

Courtesy of I. Staude and M. Wegener, KIT (Germany)

1 µm

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2. SU-8 (25, 50, 100, 3000-series)

The resists of the SU-8 series are common

negative-tone resists provided by MicroChem

Corp. They are commercially available, inexpen-

sive and their handling is unpretentious.

SU-8 is available in different viscosities, depend-

ing on the desired film thickness. The mechanical

and chemical properties make it ideally suited for

many different applications in the field of micro-

fabrication.

Photoresists

See also: M. Thiel et al., Appl. Phys. Lett. 91, 123515 (2007)

M. Deubel, PhD thesis (2006), KIT (Germany) See also: M. Thiel et al., Opt. Lett. 32, 2547 (2007)

See also: M. Thiel et al., Opt. Lett. 35, 166 (2010)

2 µm 10 µm

4 µm5 µm

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3. Chalcogenide Glass (As2S

3)

Nanoscribe provides a high refractive index

resist system for 3D micro- and nanolithography.

This negative-tone photoresist system is based

on arsenic trisulfide (As2S

3) and has a refractive

index of 2.45. In combination with the 3D laser

lithography system, it enables the fabrication

of manifold structures such as photonic wave-

guides, couplers, splitters, resonators, and 3D

photonic crystals, all of which benefit from a

material with an inherently high refractive index.

Basic Features:

» High refractive index:

n = 2.45 (at 1550 nm wavelength)

» Feature sizes down to 200 nm

» Low stress

» Little shrinkage

» Easy handling:

no pre-bake

no post-exposure bake

Phot

ores

ists See also: S. Wong et al., Chem. Mater. 19, 4213 (2007)

See also: S. Wong et al., Adv. Mater. 18, 265 (2006)

See also: S. Wong et al., Adv. Mater. 18, 265 (2006)

500 nm

1 µm

500 nm

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4. Ormocere

These organically modified ceramics are devel-

oped by the Fraunhofer-Institut für Silicat-

forschung (ISC) Würzburg, Germany.

Please contact us or refer to www.ormocer.de for

detailed information.

5. PDMS

Polydimethylsiloxane is a silicon-based organic

polymer with variable physical properties. This

viscoelastic and inert resist is biocompatible and

particularly applicable in life-sciences.

6. AZ MiR 701, AR-P-3120

Thin film positive-tone resists used in semicon-

ductor industry for 2D structuring.

7. AZ 5214

Thin film negative-tone resist for 2D structuring.

8. AZ 9260

Thick film positive-tone photoresist used for, e.g.,

electrodeposition in the resulting air voids.

Photoresists

Courtesy of T. Striebel and M. Bastmeyer, KIT (Germany) Courtesy of T. Striebel and M. Wegener, KIT (Germany)

10 µm 2 µm

2 µm

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Services

Design and Manufacturing of Samples

Nanoscribe offers the services of designing and

manufacturing client-specific samples in com-

mercially available photoresists. Customers may

submit complete structures as CAD, STL or GWL

data or solely provide descriptions and blue-

prints as guideline for the implementation of

the structure by Nanoscribe. The expenses for

structures depend on size, complexity, substrate

and resist material. Please inquire for a customized

quotation.

Casting and Coating

Nano- and microstructured devices often solely

reveal their full functionality when not only their

shape is given but also the material requirement

is fulfilled. In the last decade, a broad variety of

casting techniques has been developed in order

to transfer complex photoresist structures into

materials such as metals, semiconductors or

oxides. Nanoscribe has in-depth knowledge

in casting and coating processes and offers

expert advice on process know-how and the

implementation of customized installations.

For example, the casting of a polymer structure

into silicon can be achieved by two alternative

routes: The structure can either be inverted via a

single-inversion method (SI, left column on page

19) or replicated via a double-inversion method

(DI, right column on page 19).

Both processes involve pulsed-layer deposition

of silica which is done at room temperature.

The silica coating protects the template from

high temperatures and aggressive chemicals. For

the DI method, it also serves as an inverse tem-

plate. After this intermediate step, silicon is de-

posited in the remaining interstitial air voids via

chemical-vapor deposition. Finally, the interme-

diate materials silica (DI) as well as the polymer

(SI) are removed. As a result, the inverse of the

original structure transferred into silicon (SI) or

its replica (DI).

Serv

ice

and

Cas

ting

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Service and C

asting

See also: M. Hermatschweiler et al., Adv. Funct. Mater. 17, 2273 (2007)

N. Tétreault et al., Adv. Mater. 18, 457 (2006)

500 nm

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Nanoscribe GmbH

Hermann-von-Helmholtz-Platz 1

76344 Eggenstein-Leopoldshafen

Germany

Fon +49 7247 82 88 40

Fax +49 7247 82 88 48

Web www.nanoscribe.de

E-Mail [email protected]

Version 2.112/01/2010© 2010 Nanoscribe GmbHAll rights reserved.

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