optimizing lift-out - fib sem · direct tem sample extraction in the fib tmm 11/25/96 materials...
TRANSCRIPT
Lift-out Solutions
• Lift-out involves multiple aspects– How you cut: Total Release™ Milling*– How you lift: Plan-View TEM**– How you attach: Atom Probe Preparation*– Address many applications:
• Quality imaging for holography, high resolution TEM (Short-Cut® grid attach for backside milling)*
• Materials characterization of particles, nanowires (Short-Cut® grid attach)*
Patents issued* or pending**
How You Cut: Total Release™
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DIRECT TEM SAMPLE EXTRACTION IN THE FIB
MATERIALS SCIENCE LABSTMM 11/25/96
Pt deposition
Expose slab
Attach probe with Pt patch
Remove slab from wafer
10mm
PHEMT T-gate
Total Release™ Wedge• Cuts made using 2 angles of incidence• Most common shape for Total Release™ (all cuts
completed before attaching needle)
• Commonly used for atom probe prep, plan-view, and high volume sampling (fast lift-out)
5um 20um3um
Lamella vs Wedge (Chunk/Block)
• Automated overnight milling
• Warping during thinning or Pt welding
• Reduced area for welding
• Shifting or falling over with one free end
• Robust sample thickness
• Large area for welding• Faster thinning • Possible redeposition• Possible position
change
Milling High Aspect Ratio Trenches
• Use optimum parameters to avoid redeposition:
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Parameter Good Bad
Angle of Incidence Lower Higher
Passes/Layers (Constant Dose)
More Less
Dwell Time (Constant Dose)
Less More
Current Less More
Use Guides for Sample Position
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Use Guides for Sample Position
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Use Guides for Sample Position
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Total Release™ Benefits• Fast: less milled area = less process time
• Best for pre-lift orientation moves– Plan-view and sideways milling
– Short-Cut™ grid attach for backside and atom probe
• Eliminates/reduces “blind view” milling
• Ideal for many applications
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Time Comparison• Creating a 10µm x 5µm lamella in Si-based
material using a modern FIB
Total ReleaseLamella
FIB TIME
60 minutes 8 minutesvs
FIB Preparation of TEM Lamella • Creating a 10µm x 5µm lamella in Si-based
material using a modern FIBFrom Sample….
….To Grid Ready for Final Thinning
Omniprobe Solution Minutes
Total Release 8
Positioning the stage* 2Positioning the tip 1Attaching the tip (IBID) 3Lift-Out 1Shaft rotation* 1Grid positioning* 5Contacting the grid 3Grid attach (EBID) 4Tip detach 3
FIB Milling
INLO + Grid Attach
TOTAL FIB TIME: 31 minutes* Timings specific to plan-view samples
FIB Preparation of TEM Lamella • Creating a 10µm x 5µm lamella in Si-based
material using a modern FIBPreparation Comparison Minutes
Omni H-Bar EXLO Pre-FIB Prep 30Thinning to 1um Lamella 60 60Total Release™ Milling 8In Situ Lift-Out 23FIB Time Before Final Thinning 31 60 60FIB Final Thinning 30 30 30Total FIB Prep Time 61 90 90Ex Situ Lift-Out 15Total Prep Time 61 120 105
Wedge Visualizer
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W=4
D=7
?
W=6
D=6
?
Shallow Wedge Parameters
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2.8nA1us, 50% OL
1nA1us, 50% OL
4 um5 um
1 um
1 um 0.5 um
4um 2.5um
U-Cut Release Cut
Depth
Relatively Low Currents
10 um
2.2 um
AOI = 52o AOI = 0o
3.5’ 1.5’
Total Release™ for Lamella
• What about leveraging automated milling routines?
10µm
“J or “L” cut “T” cut
“T-Shirt Total Release”
• T-shirt Cut
3/13/2011 Acknowledgement: Kurt Langworthy, CAMCOR, University of Oregon
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How You Lift: Plan-View Samples
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Contact target Weld and lift Align grid and sample
Weld, release the tip
Plan-View Samples (and Sideways)
Shaft Rotation
Plan-View FIB “X” Solution
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Plan-View Movie
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Achieving Plan-View Samples in 30 Minutes, Start to Grid
Total Release™ Applications….….Beyond Lamellae
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EDS Maps
• Al peak indicates significant signal comes from the bulk material
Before Lift-Out
After Block Lift-Out
M. Schaffer, J. Wagner, Microchimica Acta 161, 421 (2008)
Al substrate
Cu-Ag solder
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Tomography
• Lift, Locate, Pattern, Analyze1 2
3 4
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Lift Locate
Pattern Analyze
FIB Tomography
• Orthogonal cuts made, followed by oblique cuts.
• Used for in situ 3D analysis (tomography).M. Schaffer, J. Wagner, Microchimica Acta 161, 421 (2008)
Thank You
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