Next Generation Aerosol-Based Printing for Production-Level

Printed ElectronicsD. Keicher1, M. Essien2, J. Lavin1, S. Whetten1, S. Mani1

1 - Sandia National Laboratories2 – Integrated Deposition Solutions

Introduction• Background• Development Goals• Print Head • Print Process Results

– Run time testing– Conductors– Capacitors

• Conclusions• Future Development

Background• Key Personnel

– Inventor of AJ Technology– Other AM Technology– Technical Staff and Student Interns

• Significant Experience with AJ Printing– Strengths– Weaknesses

• Leverage Sandia Technology for Improvements– Brockman, et.al. Patent, September 1999

Development Goals• Focus on User Experience with Printing

– Consistent print performance – Ease of use– Reliable– Quick material change over– Remove “Art” from operation

• Production Oriented Solution– MTBA > 4 hours– Print quality

• Well defined print edges• <5% variation for key parameters during print

– Cost of ownership

Multiple Aerodynamic Lens Aerosol Focusing• Poly dispersed particle source

– Droplets range from 200 nm to 3-5µm.– Multiple Aerodynamic Lenses

• Optimal focusing of all droplets sizes• Highly collimated print stream

– Minimizes overspray/satellites of smaller droplet sizes

2nd Lens Focuses Smaller Droplets Coaxial with Larger Droplets, Creates Highly Collimated

Aerosol Stream

Multiple Aerodynamic Lenses Enhance Focusing for Polydispersed Aerosol

Next Generation NanoJet™ Print Head Operation

1.6 cm

Cartridge Based Prototype Print Head Generation 4

Print Process Results 4 Hour Run Testing• Inks

– Clariant Preselect TPS 50 – UTDots Ag 40 silver np inks

• Substrate– Poylimide

• Configuration– New Cartridge Installation and Testing

• Analysis– Optical measurements of printed linewidth– Resistivity measurement

• Target Line width: ~ 60 microns • Test Duration – 4 hours

Results 4-Hour Test Clariant TPS 50 Ink Note Edge Definition and Line width Consistency for 4-Hour Print Test

Results Clariant TPS 50 Ink

Results 4-Hour Test UTDots Ag40x

Note Clean Edge Definition and

Line width Consistency for

4-Hour Print Test

Results UTDots Ag40X

Apparatus: NanoJet™ Ink: UTDots gold

nanoparticle ink Sintering: Thermal:

300° C Resistivity: ~3X bulk

ELECTRICAL CHARACTERIZATION OF GOLD TRACES

12

2.0

2.5

3.0

3.5

4.0

4.5

5.0

5.5

6.0

0 2 4 6 8

RESI

STIV

ITY

[XBU

LK]

SAMPLE #

Au [TRIAL 1]

Au [TRIAL 2]

Experiment: Repeatability test - Au ink printing Procedure: Print 2 sets of traces, same

parameters, Printed one week apart. Apparatus: 2-orifice NanoJet™ printer Ink: UTDots Au in xylenes

SINGLE PASS LINE HEIGHT MEASUREMENTS

v=2 mm/s

v=20 mm/s

Line height varies from ~4 to 1 micron/pass for print speeds from 2 to 10 mm/s.

13

0.5

1

1.5

2

2.5

3

3.5

4

0 2 4 6 8 10 12

Hei

ght (µ

m)

Velocity (mm/s)

Printed Dielectric Film PropertiesCross-sectional view of STA spray UTDPI sample, showing surface roughness and overspray of polymer on the film surface

Printed film thickness

Group N*avg. thickness

(μm)κ Df

AM spray UTD PI 81 6.6 (1.8) 3.05 (0.77) 0.0021 (0.0005)commercial 90 13.3 (0.2) 3.25 (0.02) 0.0021 (0.0004)

solvent cast UTD PI 31 2.6 (0.9) 3.25 (0.64) 0.0036 (0.0005)

Group N Weibull α (kV/cm) Weibull βAM spray UTD PI 69 2402 1.5

solvent cast UTD PI 54 2060 1.0commercial 89 4891 13.0

Permittivity and Dielectric Loss Mean (St. Dev)

Dielectric breakdown strength

MULTI-MATERIAL PRINTING: 3D CAPACITORSNJ Printed capacitor (a) Au (b) polyimide (c) Au with Dektak profile showing surface roughness ~±0.5µm

AB

Au/polyimide/Ag Polyimide and Ag printed using syringe dispense Single-pass (polyimide deposition) Cavg= 32.5 pF ± 2pF

Printing Ag Electrode onto Polyimide on Au Coated Glass Cylinder Printed Capacitors on Cylinder 64 – 75 pF

Printed Resistors on Glass SlideEXPERIMENTAL• UTDAg40X (0.2ml) Terpeniol (20 drops)• 200 micron tip• Sintered at 200C for 90 minutes• Sintered 50C for 60 minutesRESULTS• Lines measured ~60 microns x 20mm• Resistance = 2 kohm consistently • Lines adhered extremely well to surface

after sintering. Rubbing with isopropyl alcohol did not remove any material

• No overspray observed

Conclusions• Accomplished Goals and Objectives of Effort• Developed and Demonstrated Robust Aerosol

Print Solution• Working with Internal Customers to

Demonstrate Applications

Future Work• Test Printing to Failure• Large Area Printing• Multi Nozzle Printing• Multi Material Printing• Work with Internal and External Customers to

Apply Technology