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Aerosol Jet of 3D Printed Structural Electronics (3DPSE) for Redistribution(RDL), Wafer Level Packaging(WLP), Micro LED, QD LED and IoT Sensor.
Pascal Piera Director Sales Asia Pacific
SEMICON Taiwan 2017 創新技術發表會
Power
Healthcare
Aviation 300+50+ Issued
50+ Pending40+ 75+
Differentiated Leader in Additive Manufacturing
Aerosol Jet : Technology Overview
• High Precision Material Deposition Process
• Broad Range of Material Handling
– Conductors, Insulators, Resistors
– Bio-materials, Ceramics
• Wide Range of Geometries
– <10µm to >10mm line width
– Coatings to < 100nm thickness
– Non-contact - Well suited for 3D Printing
• Additive Manufacturing Potential
– Fewer Process Steps, Lower Material Costs
Aerosol Jet Technology Basics
Substrate
Atomize Liquid Electronic Material: conductive inks, dielectric, (1-1,000 cP) 1
41
2
2
Mist of 2 to 5 um Ø highly dense, highly loaded droplets
5
5
Print on planar and non planar substrates
3
3
Sheath gas surrounds and focuses particle beam
4
4
Continuous Flow Exits at 50m/s remains collimated for up to 5 mm
1mmto
5mm
3
4
5
Click for CFD
Animation
Aerosol Jet Key Process Advantage: 2D to 3D
Control of material beam width &
height through sheath gas & print
speed
Variable
standoff/focal length
capability
Print on oblique
angle surfaces
Control of trace width angle to
the substrate surface
Wide array of supported materials
Material Availability
Metal Inks Resistor Inks Non-Metallic Conductors
An Cuig (Pt) Acheson (carbon) Brewer Science (SWCNTs)
Applied Nanotech (Ag, Cu, Ni, Al) Asahi (carbon) Heraeus (PEDOT:PSS)
Clariant (Ag) DuPont (carbon and ruthenate) NanoIntegris (S & M WCNTs)
DuPont (Ag) Lord (carbon) SouthWest Nano (S & M WCNTs)
Henkel (AG) Methode Development (carbon) Semiconductors
Intrinsiq (Cu) Dielectrics and Adhesives Aldrich (organic semiconductors)
Novacentrix (Ag, Cu) Aldrich (polyimide) Alfa (organic semiconductors)
Paru (Ag) BASF (PVP) Merck (organic semiconductors)
Resin Designs (AgE) DuPont (Teon AF) NanoIntegris (SWCNTs)
Sun Chemical (Ag) Henkel (adhesives) Reactive Chemistries
UTDots (Ag, Au, Pt) Loctite (adhesives) Rohm & Hass (Enlight)
Xerox (Ag) Norland (UV adhesives) Shipley (photo and etch resists)
Partial Listing 0114
3D Printing of Flexible Circuits and Sensors
Art to Part Process
• CAD Model• Convert to DWG file• Tool path generated with Optomec
software
• Liquid raw material• Create fine(femto Litre) aerosol• Focus to beam(~10μm >)• Post-process(dry,cure,sinter…)
• 3D Conformal printing• Interconnects• Fine Line traces• Embedded passives• Selective Coatings• Microfluidic components
Material Resistivity
(µΩ∙cm)
TCR Yield Strength
(MPa)
Elongation
(%)
Sintering
(C)
Seebeck Coefficient
(µV/K)
Ag 1.6 3.8E-3 55 35 120 6.5
Au 2.4 3.4E-3 205 45 200 6.5
Cu 1.7 3.9E-3 117 40 220 6.5
Ni 7.0 5.8E-3 140-350 40 350 -15
Cu55Ni45 49.0 -7.4E-5 140 45 400 -35
Ag PTF 1000 100+ 170
Materials for Sensors and Flex
• Ag, Cu, Au are best electrical conductors
• Cu, Ni are harder materials with good solderability, low electromigration
• CuNi alloy has low TCR, higher resistance, high Seebeck coefficient
• Sintering of high temperature materials on low temperature substrates possible with localized heating
• Inert and reducing cover gas (H5N) inhibits oxidation of air sensitive materials
• Ink samples can be dried with laser at low power, then sintered at higher power
• Scan speeds from 1-20+ mm/s depending on power
• Sintering reactions self-limiting
Inert gas sheath
Multi-mode optics,
50µm spot size
CW Laser:100mW - 700mW
830nm
Laser Sintering
Laser Sintering Video
Silver ink printed on medical grade Silicone elastomer
• Resistance stability (extrapolated):
• Ag [uncoated] = 4.5%(ohm)/yr
• Ag [coated] = 0.4%(ohm)/yr
• CuNi = 2.75%(ohm)/yr
• Cu = 0.06%(ohm)/yr
• TCR:
Temperature Coefficients
*https://www.allaboutcircuits.com/textbook/direct-current/chpt-12/temperature-coefficient-resistance/
Material TCR (measured) TCR (literature)
CuNi 3.7E-4 C-1 7.4E-5 C-1
Cu 2.7E-3 C-1 4.0E-3 C-1
Ag 2.1E-3 C-1 3.8E-3 C-1
Au 1.4E-3 C-1 3.7E-3 C-1
Constantan (left) and Copper (right) strain gauge
Wheatstone Bridge Circuit diagram
Strain gauge on steel beam showing 3D interconnects
Flex Application: Strain Gauges
Strain Gauge Performance
• Cyclic bending over 60 mm diameter pipe (0.6% strain)
• >5,000 flexes without signal degradation
CuNi gauge on 0.005” Kapton
Copper–Constantan Thermocouples
• Two different CuNi formulations
• Cu55Ni45
• Cu50Ni50
• Seebeck coefficient approaches type T thermocouple (Cu / Cu55Ni45)
• Pad to pad resistance ~2kOhm
S=43.6 uV/K
S=30.6 uV/K
S=22.9 uV/KCu CuNi
Stretchable wires on Medical Grade Silicone
Xiaowei Yu, Bikram K. Mahajan,Wan Shou and Heng Pan, Micromachines, December 2016
2 mm
Trace Width
200um
Silver serpentine wire printed on Silicone
2D pattern
Line profile
Lines terminated with solderableCopper pads
Geometric Approach to Stretchable Conductors
Resistance = 9 W over 100 mm Length
Line resistance flat to
10% elongation
Stretch
Failure mode at high strain
Hemisphere
stretches
silicone wire
Survives ‘crumple test’
• Air sensitive copper-based materials printed with Aerosol Jet
• Local sintering with laser inert shield gas results in high conductivity
• Laser sintering high-temp materials on low-temp substrates
• Cu and Cu-alloy strain gauges cycled over 5,000 times on Kapton
• Copper-Constantan printed thermocouples demonstrate linearity
Summary
Aerosol Jet of 3D Printed Structural Electronics (3DPSE) for Redistribution(RDL), Wafer Level Packaging(WLP), Micro LED, QD LED and IoT Sensor.
Peter Chiu General manager
SEMICON Taiwan 2017 創新技術發表會
3D printing additive manufacturing service providers
DETEKT
3D Printed Electronics Service
–Electronic Circuit Print
– Micro LED
– Wearable sensors
– PCB
– Antenna
– RDL on FOWLP/FIWLP
DETEKT Open house 2017
“DETEKT Open house 2017」” comprehensive display of DETEKT in the 3D printed medical,
electronic circuits, semiconductor, aerospace and R&D application technology to build energy.
At 2020,Market will rise to 12 billion USD
Printed Electronics
Picture Source:
Dimatix/FUJIFILM
Electronic Device
application
Solar Panel
Computer
Automobile
Aerospace
Robot
MobileTouch panelFlexible PCB
Sensor
3D complex lines
Special material
Deposition head module
Aerosol Jet 300
[Patent number: US 7485345 B2, 2005]Apparatuses and methods for maskless mesoscale material deposition
100μm Tip
10μm Beam
Minimum fine line width: 5μm~10μmMinimum single layer thickness: 50nm~100nmPitch between line: 15~20μmAvailable substrates: Flat, 3D surface
Official Capability
Aerosol Jet Technology
Redistribution Layer RDL
• Flip chip assembly is one advanced packaging solution
• Flip chip bumps provide both mechanical supports and electrical
connections
• Short interconnects, low inductance, better electrical
performance
• Requires underfill to improve the long term reliability
• Fine pitch, area array, high density interconnect
• Need an interposer to redistribute the I/Os to a coarser
pitch for board level assembly
• Redistribution layer (RDL)
• Replace interposer, thinner package
• Fan-in RDL redistribute the I/O from peripheral array to area
array (Chip Scale Package)
• Larger solder joint for more robust SMT process
• No underfill is needed
• Fan-out RDL redistribute the I/O on the chips to the molding
compound
• Package-on-Package (Apple A10)
• SiP (multi-chips)
FIWLP and FOWLP
FIWLP and FOWLP
Wafer Level Chip Scale Packaging (WLCSP)
• Small package size (same as the chip size) with a coarser pitch, more robust assembly process
• Utilize solder bump instead of long bond wire to achieve better electrical performance• Short interconnection path reduces transmission delay and
hence increase the circuit bandwidth
• Low I/O capacitance and inductance• Favor high speed signal transmission
• Low impedance• Favor power transmission• High current flow by low voltages
• WiFi/BT combos, transceivers, PMIC and DC/DC converters, analog/digital/mixed signal devices including MEMS and image sensors
• Various types of CSP• Bump on Repassivation (no redistribution layer)• Bump on Nitride (polymer is not subjected to stress by has a
higher parasitic capacitance)• Bump on Redistribution (low parasitic capacitance)
• Wafer level packaging process• Low cost, high throughput for mass production• High cost for prototyping
Bump on Repassivation
Bump on Redistribution (with UBM)
Bump on Redistribution (without UBM)
Conventional RDL Fabrication Process
Silicon
Silicon
Silicon
Silicon
Silicon
Silicon
Silicon
Passivation Deposition
Al Pad Patterning (1st Mask)
Dielectric Layer Patterning (2nd Mask)
Redistribution Layer Deposition and Patterning (3rd Mask)
Passivation Opening (4th Mask)
Aerosol Jet RDL Fabrication Process
Ref. Hong Kong University of Science and Technology EPACK Lab.
Test Chip
Silicon
1. 0.5 um Al Deposition and Patterning (1st Mask)
Silicon
0. Si Wafer with 1 um SiO2
Silicon
2. 1 um SiO2 Dielectric Deposition and Patterning (2st Mask)
Al Pad
40 um Dielectric Opening
Al Trace (10 um width)
3 mm by 3 mm
Chip Boundary
Dicing Mark
Al Daisy
Chains
Ref. Hong Kong University of Science and Technology EPACK Lab.
Printed RDL
Silicon
1. Test chip
Silicon
5. Conductive metal (Ag) layer for RDL
Silicon
6. Passivation polymer (240 um opening for solder ball)
Silicon
2. Conductive metal (Ag) on Al pads
Silicon
3. Dielectric polymer dam (35 um opening)
Silicon
4. Dielectric polymer on the entire chip
RDL design Microscopic
image
Ref. Hong Kong University of Science and Technology EPACK Lab.
Surface morphology measured by optical profiler
Surface Morphology of the Printed RDL
Ref. Hong Kong University of Science and Technology EPACK Lab.
Package Characterizations
• Performed by Hong Kong University of Science and Technology EPACK Lab.
• Electrical performance characterization (compare RDL by conventional processes and 3D printing)
– Signal integrity
– Power integrity
• Reliability tests (compare RDL by conventional processes and 3D printing)
– Solder ball shear/pull test
– Package shear/pull test
– Thermal aging
– Moisture sensitivity level characterization
– HAST (package level)
– Thermal shock (package level)
– Thermal cycling (board level)
– Drop test (package and board level)
• Failure Analysis
– Cross-section inspection
– SEM/EDX inspection
Printing m3D structures with Aerosol Jet
UV polymer ink
Vertical Build
UV illumination
0.5 mm
•Precision spacers•Interposers•Controlled surface texture
•3D composites•MEMS
•Micro fluidics•Scaffolds•3D electronics•mm-wave antenna
Micro LED, QD LED
ConclusionsDirect attachment of LED die to the heat sink results in a significant reduction in Rth between the junctionand heat sink allowing either increased power densities or reduced heat sink requirements.Aerosol Jet printing is able to write the necessary interconnect traces and conductive adhesive on low-costanodized aluminum needed to make this approach practical.
High LED junction temperature leads to reduced LED output and color shift, and is a factor in most LED failuremechanisms. Every interface and layer of packaging between the junction and the heat sink increases thedevice operating temperature necessitating more aggressive heat sink design. Packaging also increases thefootprint of the device, limiting packing density. The ideal design would have the bare LED die attacheddirectly to the heat sink with a micron-scale bond of thermally conductive adhesive.
LED die attached directly to an anodized Al heat sink
LED mounted directly on the heat sink with junction up(A) junction down (B) and junction down enlarged to show the silver and silver-epoxy(AgE) electrical connections.
Direct Wire Printing
Direct Write Printing on Thin and Flexible Substrates for Space Applications
Summary (I)
• Packaging play an important role in device overall performance
• RDL is the key element in both Fan-in and Fan-out WLP
• Process on a whole wafer (material deposition, photolithography, electroplating, polishing, bumping)
• Not suitable for singulated chips and devices with complicated 3D structures
• High fixed setup cost, large volume is required for cost effective production
• No universal routing layout
• Expensive to apply RDL on singulated chips
• RDL by 3D printing is an enabling technology for small volume CSP prototyping
• Low cost in small volume production
• Flexible in design, fast turn-around time
• Maskless or less mask packaging by aerosol jet is the great solution
Summary (II)
• Aerosol Jet has significant advantages for manufacturing antenna on 3D substrates
• Many commercial materials compatible with Aerosol Jet
• Direct printing is a high throughput production solution with comparable antenna
performance to existing processes
• Material flexibility of Aerosol Jet process enables the additive manufacturing of a wide
range of sensors
• AJ offers a complete solution for the production of networked IoT devices
Peter Chiu Ph.D
General manager
+886-2-2267-3158
Pascal Piera
Director Sales Asia Pacific
Thank you for your attention！
