The quest for ultimate patterning tools and techniques

11th European FIB Users Group MeetingMonday 8 October 2007 Arcachon

The quest for ultimate patterning tools and The quest for ultimate patterning tools and techniques techniques -- Focused Ion Beams : Status Future Focused Ion Beams : Status Future

Applications and New IdeasApplications and New Ideas

J. Gierak, A. Madouri, B. Schiedt A. L. Biance, G. Patriarche, L. Auvray1 and R. Jede2

LPN-CNRS Route de Nozay, F-91460 Marcoussis1 MPI, Université d’Évry Val d’Essone, Bd. François Mitterrand, F-91025 Evry2 Raith GmbH, Hauert 18, Technologiepark, D-44227 Dortmund, Germany


111 - Introduction

222 - The nanoFIB project

333 - Highest demonstrated patterning resolution

444 - Applications – Experimental results

555 - Conclusions & Perspectives


1INTRODUCTION

FIB Technology

Device modification

Mask repair

Process control

Failure analysis

TEM Lamellae preparation

Challenges for nanotechnology = Development of tools, techniques and methods for the

patterning of materials on the nanoscale

Technology for mass-production Tools for rapid prototyping of

individual nanodevices


• Nanomagnetism: Ion Beam mixing experiments at record low doses & resolution (J. Ferré Lab. Phys. Sol.)

• Artificial defects: Surface functionalisation- Surface bumps (L. Bardotti, LPMCN)- Nanopits (H. Hövel; Univ. Dortmund)

• Focused Ion Beam lithography on thin films- Local epitaxy of GaN, InP, GaAs (P. Gibart CRHEA, I. Sagnes LPN-CNRS)

- Aluminium film as inorganic mask for Si processing (M. Villaroya UAB)

• Artificial nanopores- Biology (L. Auvray, A.L. Biance Univ. Evry)

- Shadow deposition techniques

• Nanowires …

ADVANCED FIB A P P L I C A T I O N S


1. The machineBeam quality compatible “nano”Advanced patterning modesSample handling

2. Ion SourceHighest brightnessStability- Lifetime

3. Ion OpticsBeam size sub-10 nm (FWHM)Probe current 2-10 pA30 to 40 kV

4. Platform configurationLaserstageClean and low vacuum- Loadlock

5. Patterning strategiesGDSII software platformMetrology

NanoFIB : T H E I D E A

2


RAITH GmbH, Hauert 18, Technologiepark, D - 44227 DORTMUND

FuG GmbH,Florianstrasse 2, D - 83024 Rosenheim

CEMES/CNRS, 29 rue Jeanne Marvig, BP 4347, F - 31055 TOULOUSE CEDEX

CPO Group, Delft University of Technology, Lorentzweg 1, NL - 2628CJ DELFT

Commisariat à l'Energie Atomique DECM/SRMA/LCMS F - 91191 Gif sur Yvette

Universitaet Essen Institut Chemie Universitaetsstrasse 5-7 D - 45117 Essen

Laboratoire de Physique des Solides, Université Paris-Sud, F - 91405 Orsay

University of Surrey, School of Electronic Eng. UK - Guildford Surrey GU2 5XH

Institute of Scientific Instruments, Acad. of Sciences, Králov. 147, 612 64 Brno

NanoNano--fabrication with Focused Ion Beamsfabrication with Focused Ion Beams

LPN/CNRS, route de Nozay, F - 91460 MARCOUSSIS

NanoFIB : T H E C O N S O R T I U M

GROWTH Contract European Commission


33.a. G a l l i u m L I Q U I D M E T A L ION SOURCE

I D E A L F O R N A N O - F A B R I C A T I O N ?

Energy width E min ~ 4,5 eV

Virtual source size: dv ~ 30 à 50 nm

Angular density dI/d = 20 µA/sr

Brightness r ~ 106 A/cm².sr

Liquid

Taylor-Gilbert coneof liquid metal

Ion emission

Solid tip

metal flow

Off-AxisEmission

Droplet growthand emission

Balance (Taylor 1964)

)11

(2

1

21

2

0RR

E

Ion Beam

Extractor

Reservoir

Liquid metalV < Vth V > Vth

Taylor cone

W tip

Heating loop


(Swanson et al 1988)

Beckman 1996

(Driesel 1995)

(Sudraud 1984)

I N T R I G A T I N G F U N D A M E N T A L QUESTIONS S T I L L O P E N


INTENSIVE E F F O R T

LMIS R E S E A R C H A N D D E V E L O P M E N T


OPTIMISED G E O M E T R Y C A P A B L E O F L O N G – T E R M S T A B I L I T Y

Strong supply function

Tungsten tip rc ~ 10 µm

Very low sensitivity to contamination - Stability & Time of life

Emitted current regulation method (CNRS Patent)

1 MV 100 nm

0 500 1000 1500

0

5000

10000

15000

20000

25000

30000

35000

Em

itte

r vo

ltag

e (

V)

Time (s)


16,9 17,0 17,1 17,2 17,3 17,4 17,50

1

2

3

4

5

6

7

8

9

10

dI/d

V=

38.3

µA/k

V

dI/dV = 8.4 µA/kV

Em

issi

on c

urr

ent

(µA

)

Extracting voltage (kV)

STABLE AND LINEAR I–V C H A R A C T E R I S T I C S

Gallium = 5910 kg/m3, = 0,72 N/m et m = 1.16. 10-25 kg jet radius ra = 1,09 nm

3/2

)3/2(e

imr

Mair 1986


0,008

0,0085

0,009

0,0095

0,01

0,0105

0,011

0,0115

0,012

0,0

0

0,9

2

1,7

8

2,6

3

3,4

8

4,3

3

Time (hours)

Bea

m C

urr

en

t (n

A)

OPTIMISED G E O M E T R Y C A P A B L E O F L O N G – T E R M S T A B I L I T Y

Slope < 0.5% in 1 hour

“Flashing” not required

Slope < 0.5% in 1 hour

“Flashing” not required

Cold startCold start


(1) Since # 30 to 50 nm Optics magnification <<1

M. = dG < 10 nm

M < 0,3

(2) Low Cc if

(3) Strongly collimated mode: o = 0.1 to 0.2 mrd

(4) All electrodes are mechanically “auto-aligned” on a single optical axis

d² =dG2+ dch

2+dsp2 +dal

2

i

o

f

fM #

0V

VCd cch

3

02

1spsp Cd

X-Short WD = Single beam architecture

High local field ~10 kV / mm (Critical)

Very low Tails (Rejection)

Low spherical aberration coefficients

“No” Alignment aberrations

3.b. O P T I M I S E D ION OPTICS

3


Calculation and optimisation via CPO modelling

Magnification 6.33 nm 4.95 nm 2.98 nm

Aberrations

Cc 1.76 nm 2.45 nm 2.92

Sp 0.03 nm 0.06 nm 0.33 nm

Probe size 6.57 nm 5.53 nm 4.27 nm

(FWHM)

SUB-10 nm D E S I G N E D I O N O P T I C S

2 4 6 8 10 12

4,0

4,5

5,0

5,5

6,0

6,5

7,0

7,5

8,0

8,5

9,0

9,5

10,0

10,5

Gen#1

Gen#2

Gen#3

Pro

be

dia

me

ter

-FW

HM

50 (

nm

)Working distance (mm)

WHILE K E E P I N G A C C E P T A B LE P R O B E C U R R E N T

Ion source geometry (LMIS),Design of extraction region,

Operating parameter

dI/d > 50 µA/srd Ip ~ 2 to 5 pA


-50 -40 -30 -20 -10 0 10

-2

-1

0

1

2

3

4

z [mm]

x[m

m]

Electrode 0 V

Electrode -19 kV

Deflector

B E A M C H A R A C T E R I S T I C S F I E L D D I S T O R T I O N

ANLYSIS A N D OPTIMISATION

Deflected and undeflected beam (scaled x10) for a 35 keV Ga ion beam

Deflection aberrations kept close to the size of the undeflected beam (Max field size ~ 65 µm)


Laser-interferometer stage

• Stitching < 60 nm

(2 in 50-µm field)

• Overlay < 60 nm(2 in 50-µm field)

150-mm travel range

1-nm positioning

Extended lines FBMS mode

with

- Length > 1 mm

- Width < 30 nm



Pattern Generator and software

Dedicated lithography

software suite

20-MHz, 16-bit Digital Pattern

Generator

6 filling modes with about 20

sub-modes

Supported patterns: polygons,

boxes, circles, lines, dots,

wedges (for cross-sectioning)

multi-user management



Stitching-free writing of elongated structures

Fixed Beam Moving Stage : continuous moving stage along pathsposition control via Interferometeron-the-fly beam position correction

mm distances patterning of nm sizes features



Pattern Generator and software

For rapid prototyping

Acquire ion-beam image.

Draw any shape on it.

Define process parameters

and execute process.

Save shapes, if necessary.

POI = Patterning over images



Nanomanipulation

NMT1

GISNMT2

Integration ensures

Collision free operation

Intuitive operation and automation



3.c. T H E P R O T O T Y P E A T LPN-CNRS

3GROWTH Contract European Commission


E X P L O R A T I O N O F T H E FIB U L T I M A T E P O T E N T I A L

J. Ferré, C. Chappert et al.

(Univ. Paris Sud)

P. Gibart, B. Beaumont

(CRHEA - Lumilog S.A.)

I. Sagnes, S. Bouchoule

(CNRS-LPN)

B. Prevel, L. Bardotti, A. Perez

et al. (LPMCN UCB Lyon1)

G. Schmid (Institut für

Anorganische Chemie,

Essen – Germany)


-20

-10

0

10

20

-20-10 0 10 20

x nm

y nm

-20

-10

0

10

20

0

20 40 60 80

y nm

x nm

Part 1. NANOMAGNETISM – Top DownJ. Ferré, J.-P. Jamet, A. Mougin, C. Chappert, V. Mathet

• 30 KeV Ga+ gaussian spot (FWHM < 10 nm)

• FIB patterning process based on defect injection

• Well below sputtering (1018 1012 ions/cm²)

• No “protective” layer (redeposition, beam tails, …)

• Low dose & high speed patterning envisioned

• Surface kept flat

Shot noise ?

Methodology


TRIM based mapping of the vacancies created by the impact on a target of a 8 nm probe

transporting 37200 gallium ions (30 keV).

I O N B E A M A S S I S T E D MIXING S M O O T H I N G

100 200 300 400 500

-200

0

200

Vacancy CreationDensity

1x1021

cm3

Depth, z (Å)

Late

ral d

ista

nce

(Å

)

1,000

10,00

100,0

200,0

300,0

400,0

500,0

750,0

1000

Mapping detail

0 100


Dot size: 1800 nm 900 nm

340 nm 70 nm

Magneto-optical images (18 µm x 18 µm) of thecentral part of the demagnetized dot arrays

Remnant magnetic hysteresis loops of

Pt/Co(1.4nm)/Pt dot arrays determined by

magneto-optical microscopy (MOKE).

Hysteresis loops evidenced for 70 nm dots

Evidence for Dipolar Coupling

F A B R I C A T I O N O F MAGNETIC ARRAYS c


Dose

T c

295 K

x

PARAMAGNETIC

MAGNETIC

FERRO-

MAGNETIC

DOT

IRRADIATED LINE

FERRO-

MAGNETIC

DOT

FERRO-

MAGNETIC

DOT

FERRO-

MAGNETIC

DOT

• High ion deposited doses (> 1015 ions/cm²)

= paramagnetic lines / etched lines

• Moderate fluences (< 1015 ions/cm²)

= lines with reduced coercivity

•Paramagnetic parts of lines cut the Exchange

Coupling leaving the longer range Dipolar Interaction

(Hd)

•Soft border acts as a reservoir of low field nucleation

centers in each dot allowing rapid reversal under the

influence of local dipolar fields.

• Very high patterning speeds demonstrated (200

mm/s) Record value for a sequential patterning

technique

Hc REDUCED

D A M A G E P R O F I L E I N F L U E N C E S MAGNETIC PROPERTIES


60 m

Nucleation : H = 175 Oe, t = 40 s

Domain wall propagation : H = 70 Oe

40 µs t 20 s

40 µs t 50 s

50 s t 60 s

t 40 µs

H(Oe)

-24

-22

-20

-18

-16

-14

-12

-10

-8

0.2 0.3 0.4 0.5 0.6 0.7

Ln

[V(m

/s)]

H(Oe)-1/4

102050100500 5

V(m

/s)10

-6

10-8

10-4

10-10

piste de

0.9 micron

0.45 micron

multicouche

vierge

piste de

Propagation of a magnetic domain in a 0.9

µm track under a constant applied magnetic

field of 70 Oe. (MOKE images at : 540 nm).

Giant enhancement of the domain wall velocity

•Soft border acts as a reservoir of low

field nucleation centers allowing rapid

propagation of a magnetic domain.

F A B R I C A T I O N O F CHANNELS


NANOMAGNETISM – Bottom UpL. Bardotti, B. Prével, P. Mélinon, A. Perez

# 102 ion impact

(Ga+, 30 KeV, 8 nm, HPOG target)

# 104 ion impact


TMAFM images (980 nm x 980 nm) Array of defects created by FIB (HOPG substrate, 35

keV Ga+ ions, probe size # 6 nm, N=3750 ions/pt

Perspective = Auto-organisation


F I N A L L O W E N E R G Y C L U S T E R B E A M DEPOSITION

(a) Gold film deposited on HOPG FIB patterned

TMAFM (2 µm x 2 µm)

(b) Co50Pt50 magnetic clusters (2 nm mean

diameter) deposited on HPOG FIB patterned

• Deposition of pre-formed nanometre-sized clusters on FIB patterned surfaces

• Cluster formation and substrate functionalisation are completely independent


Part 2. NANOPORES : N E W C H A L L E N G E F O R F I B T E C H N O L O G Y

(A. Illie 2005)

FIBNanoelectronics

NanoBiology

Work supported under

ANR project “Active nanopores”

L. Auvray Univ Evry


ULTRA THIN S I C M E M B R A N E S ( < 6 0 n m )

Silicon wafer <100> e ~ 280 µm

Thermal oxidation – 950°C

Resist spin coating

Development

SiO2 etching

Reactive Ion Etching

Silicon etching (TMAH)2

2222 )(222 OOHSiHOHOHSi

Strain optimization: thermal treatment

SiO2 removal (AF)

SiC deposition: e ~ 10-110nm


H I G H R E S O L U T I O N

SHADOW MASKS

Pattern placement, organisation and metrology

FIB nanowriter architecture

Batch processing


min. dose (~5.105 ions/dot)

MAX. dose (~5.107 ions/point)

N

0

20

40

60

80

100D (nm)

106 107 108 109

N

20 nm

80 nm

110 nm

Pore

dia

mete

r (n

m)

Number of ions / point

ULTRA HIGH R E S O L U T I O N N A N O P O R E S

Part 1 : D O S E C A L I B R A T I O N A N D B E A M S H A P I N G

Critical dose

4


Part 2 : O R G A N I S I N G A N D R E T R I E V I N G SINGLE N A N O P O R E S - A N E E D L E I N A H A Y S T A C K ?

50 nm x 50 nm TEM images of nanopores

20 nm thick membrane, same point dose ~106 ions.

3 nm < 3 nm

Centred nanopore

Alignment mark


Membrane

MECHANISMS F O R U L T R A N A R R O W N A N O P O R E S

F A B R I C A T I O N

(2) Stamping Edc > Binding

energy

(3) Forward

scattering

FIB

Sample

10 nm

SRIM based simulation of

damages generated by a 35

keV Ga+ impact

(1) Upper side Sputtering


CONCLUSIONS & PERSPECTIVES5http:/www.cordis.lu/nanotechnologyhttp://europa.eu.int/comm/research/industrial_technologies/30-06-03_pro-nanofibhttp://www.nanofib.com

• « Nice story » « FP5-EC success story » (...)(...)

• Successful Very ambitious instrumental research & development

Mix instrumentation with leading edge application teams

Efficient support and Guidance

Seeding germ for Future Applications & New Ideas

• Perspectives:

- Partnership & Expertise continues to grow

- New challenges exploration via nanoFIB technology

- Exploration of the ultimate patterning capabilities of FIB technique


Acknowledgements are due to …


Merci !!

Merci !!Herzl

ichen

Herzlich

en DankeDanke

!!!!Société Française de Physique

Prix Yves Rocard 2007

Ralf Jede

Jacques Gierak

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The quest for ultimate patterning tools and techniques