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Transcript of $SSOLFDWLRQV 0DUNHWV · 2017. 3. 18. · Microsoft PowerPoint - INV5-NanoCopper-AAZinn-b Author:...
A Novel NanoCopper-Based Advanced Packaging Material
Dr. Alfred A. Zinn
Kuprion Inc.
Core Team: Dr. Randall Stoltenberg, Jerome Chang, Yenling Tseng, Shannon Clark
Lockheed Martin Space Systems Company Advanced Technology Center
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Flowable, nanoCopper “metal-adhesive”
and printable ink – pressure-less
sintering as low as 200C forms solid
metal with high electrical and thermal
conductivity.
• Large-scale manufacture
• Product formulation
• System application & assembly
• Many products / markets
Scaled-up productionnanoCu paste
Solder-free electronics
HIGH PERFORMANCE, HIGH RELIABILITY SOLDER-FREE
ELECTRONICS
NanoCopper Metal Adhesive
Thermal interface
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Electronic Solder-like
Pastes
3D Printable
Inks
Emulsions/ Coatings
High-Reliability Electronics & Packaging
1 kgPilotplant
PhotovoltaicsFlexible / Printed Electronics (e.g phased array antennas)
Flat Panel Displays /Touchscreens
Thermal Interface Applications3D Electronics
Packaging
Low Temp.Cu / Al Brazing
Courtesy NASA
Co
urte
sy NA
SA
CuantumFuse™ Materials PlatformAddresses Many Applications & Markets
CUANTUMFUSETM COMBINES THE BENEFITS OF COPPER (PERFORMANCE, COST)WITH INDUSTRY-COMPATIBLE LOW-TEMPERATURE PROCESSING
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Demonstrate Scaleability for Cost Reduction
• Industrial scale production
– Economy of scale = minimizes materials & labor cost
– Commodity material requires competitive pricing
• Enabled by single “pot” process:
– Mix precursor and surfactants
– Add reducing agent
– Isolate powder
• Setting up & qualifying supply chain
– Yield increased to over 1 kg per batch
100 L PILOT PROCESS >1 KG NANOCOPPER
100 L reactor>1 kg / batch
ATC pilot plant
The Future:
IndustrialScale
(>100 kgper batch)
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2015-2016 Process Improvements
• Raw nanoCopper Cost Reduction
– Yield approaching 95%
• Process Chemistry Improvements
– Replace original solvent due to phase-out (REACH)
• Improved process characteristics (no foaming)
• Manufacturing Process Scale-Up
– Cost reduction through further scale-up and process stream-lining
• >1 kg batches
YIELD APPROCHING 95%
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Fuses to form solidcopper slugs
Hard, dense, metallic luster, behaves like Cu
Agglomerated raw nanoCu powder
NanoCopper Morphology (TEM / SEM)
PRESSURE-LESS FUSION TO SOLID COPPER
Fusion
Raw nanoCopper paste
Fused state: crystalline copper grains
20 nm20 nm
Energy (keV)
Cou
nts
50
3000
2000
1000
0
C
Cu
Cu
CuCu
Au
O
C & Au are from TEM Grid
Agglomerated Raw Powder
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• Bonds well to low activity bulk copper surface
• Widespread cohesive ductile failure
– Responsible for high strength = true metal bond
• Average range around 6000 psi
– Equals current space qualified solder (4-8ksi)
EQUALS STRENGTH OF SPACE QUALIFIED SOLDER
Fracture Surface Analysis
Cohesive ductile failure
Effective bonding to bulk Cu
Extensive shear deformation
Stress – Strain Curve
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LED Bonding Application• Over 130 formulations evaluated
– Repeatable dispensing of less than 0.1 mg
• Improved Rheology
– Can readily dispense >4g/mL dense paste
• using standard solder dispensing equipment
– Paste is stable, does not “cream”
• Paste density can now be controlled
– Can dial-in to over 5 g/mL
• Over 90% Cu by weight!
DENSITY > 3.7 g/mL, > 90% BY WEIGHT CU
Assembled Emitter
Dispensed nCu
After die placement
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Cross-Section and Porosity• Very thin bond layer
– 2-10 micron
– High heat transfer rate
• Conforms well to rough surface
• Low porosity
• X-ray analysis comparison
NO LARGE VOIDS – HIGHLY UNIFORM
No voidsPotential for long life
Commercial AuSn solder
Multiple large voids
– Chance of early failure due to burn-out
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MMIC onENiPG/Metgraf
SIGNIFICANT IMPROVEMENTS IN SHEAR STRENGTH AND REPRODUCIBILITY
LED Shear Test ResultsComparison with AuSn
Mil-spec
• LEDs as test vehicles
• 5 LEDs per run
• Shear test as high as 9 kg
– Mil-standard for 1 mm2 is ~ 600g
• Starting to test larger dies– 2 x 4 mm MMICs
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Shelve-Life Investigation
• One large batch split into 12
samples
• Periodic testing and retesting
over 8 months
• Doubled shear strength over
first 4 months
• After 7 months start to see drop
off in strength
FOUND 7 MONTH SHELF-LIFE
Test vehiculelayout
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SMT Bonding
• Good bonding to Cu, Ag, Au,
ENIG, Sn / SAC
– In some cases over 80MPa
– Average around 50 MPa
– Voltage regulators
– BGA and QFP packages
– 26 pin through-hole connector
Broken ResistorContact ripped off
BGA (208)
68 pin QFP
26-pin through-hole connector
5-lead voltage regulators
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Printing Applications
• Initial demonstration of:
– As narrow as 25 micron
– 250 nm to 2 micron thick
– Six passes on top of each other
– Bumps / pillars >60 micron tall
(10 x 10 arrays)
• Applications in 3D printing &
additive manufacturing
– Potential for injection molding
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Overall Materials Advantages
• Special features:
– Processing temperature as low as 200C
– Drop-in replacement for solder
– Good adhesion to Cu, Ag, Sn*, SAC*, ENIG
• Up to 10x higher thermal / electr. conductivity compared to solder once fully optimized
• Tin-whisker-free
• No Cu dissolution or pad weakening / failure
• No brittle IMC formation / no gold embrittlement
ENABLES RELIABLE ALL-COPPER SYSTEMS
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