1. No category

High throughput TEM
sample preparation using
automated FIB preparation
Hans-Jürgen Engelmann1), Dirk Utess1), Enrico Vales1), Lars Heller1), Alexander
Würfel2), Heiko Stegmann3), Ralf Lehmann4)
1) GLOBALFOUNDRIES, Dresden; 2) GWT Dresden; 3) Carl Zeiss NTS GmbH,
Oberkochen; 4) FEI Deutschland GmbH, Kassel
Introduction
decreasing feature size, new materials and the introduction
of new process steps require more and more TEM samples
number of TEM samples per year (AMD/GF Dresden)
5000
4500
4000
3500
3000
2500
2000
1500
1000
500
0
1999 2000 2001 2002 2003 2004 2005 2006 2007 2008
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GLOBALFOUNDRIES/CCA
Introduction
TEM has become a valuable tool for
• process control
• physical failure analysis
• process development
currently
used TEM
techniques
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•Imaging (bright field & STEM)
•Analytics (EELS, EFTEM, EDX;
Line-Scans & Mapping)
•Strain analysis (NBD)
•3D imaging (tomography)
•Determination of dielectric constant
(VEELS)
•Grain orientation maps (DFD)
•Band gap measurements (VEELS)
•Pore size measurements
•p-n transitions (Holography)
GLOBALFOUNDRIES/CCA
Introduction
TEM sample preparation at AMD/GF:
• 95% target preparation
• 95% FIB preparation (H-bar)
• 3% FIB preparation (lift-out)
• 2% classical cross-section preparation
How to increase number of TEM samples with nearly
the same lab manpower & lab tool capacity?
application of automated TEM sample preparation
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GLOBALFOUNDRIES/CCA
H-bar samples
1. Mechanical pre-preparation
30…50 µm
2. FIB preparation
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GLOBALFOUNDRIES/CCA
Tools & Software
1) NVISION 40 (Zeiss)
ASP software
2) Strata 400 (FEI)
AutoFIB® software
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GLOBALFOUNDRIES/CCA
Sample preparation @ NVISION 40
Steps:
• Pt outgassing
• stage point list for TEM grids
• eucentricity
• accurate FIB alignment
• detector/scan-speed/noise reduction
• start ASP
• template selection
• selection of desired location
• metal deposition definition
• position of boxes
• align mark definition
• drift correction definition
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GLOBALFOUNDRIES/CCA
Sample preparation @ NVISION 40
Process (lift-out sample):
1. Alignment mark
4. Medium milling
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2. Pt deposition
3. Coarse milling
5. Fine milling
6. Cut out
GLOBALFOUNDRIES/CCA
Sample preparation @ NVISION 40
Reproducibility:
average thickness of the
prepared nine lamellae:
71 ± 4 nm
(application of
‘fine correction’)
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GLOBALFOUNDRIES/CCA
Results: NVISION 40
• number of TEM samples per run:
- max.12 H-bar samples
- (arbitrarily) many lamellae on the bar
• lead time per sample/lamella: 6…10 min
• yield: 95%
(if well aligned & stage shows no mechanical clearance)
• lamella final thickness: About 60 nm
(depends on ion column alignment)
• surface damage: Protection layer is required
(80 pA ion beam is used for positioning)
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GLOBALFOUNDRIES/CCA
Sample preparation @ Strata 400
Steps:
• sample adjustment (eucentricity, x/y alignment)
• start Autofib.exe and RunScript.exe
• recipe selection
• selection of desired location
• Pt deposition for cross-marks
• cross-marking
• definition of boxes
• Pt protection layer definition
• run now
(this script was developed originally
for lift-out samples, now it has been
adapted for H-bar samples)
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GLOBALFOUNDRIES/CCA
Sample preparation @ Strata 400
Process (H-bar sample):
1. Alignment mark
4. Coarse milling
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2. Fine Pt deposition
5. Fine milling
GLOBALFOUNDRIES/CCA
3. Pt deposition
6. Final Width
Sample preparation @ Strata 400
Process:
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GLOBALFOUNDRIES/CCA
Results: Strata 400
• number of TEM samples per run:
- max.6 H-bar samples
- (arbitrarily) many lamellae on the bar
• lead time per sample/lamella: About 10 min
• yield: 100% (if well aligned & good samples)
70…80% (if difficult samples)
• lamella final thickness: 80 nm with high reproducibility
(currently according to the width of the Pt protection layer)
• surface damage: Thick protection layer is required
(2800 pA ion beam is used for positioning)
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GLOBALFOUNDRIES/CCA
Acknowledgement
The financial support by the German Federal Ministry for
Education and Research, FKZ 13N9431, is gratefully
acknowledged.
28.07.2009
GLOBALFOUNDRIES/CCA