Novel Precipitation Method for Producing Novel Precipitation Method for Producing Dispersed Crystalline Copper PowdersDispersed Crystalline Copper Powders

for Electronic Applicationsfor Electronic Applications

I. Halaciuga, S. LaPlante, and D.V. GoiaClarkson University, Potsdam NY

CARTS USA 2009, The Passive Components Symposium and Exhibition

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FundingAdvisors:Prof. Dan V. Goia (Chemistry)Prof. Vladimir Privman (Physics)

Collaborators (students / postdocs):Dr. D.T. Robb (Berry College - GA)Dr. D. AndreescuDr. M. Jitianu (Rutgers University)Dr. R.K. Roy (Indian association for the cultivation of science)C. GoiaS. Chevalliot (University of Cincinnati)S. Reiche (Max Planck Institute - Berlin)D. Le (University of North Carolina at Chapel Hill)I. SevonkaevB. FarrellK. BalantrapuB. MorrowS. LaPlanteL. LuN. PorterW. Olson (General Electric)G. Burkey

www.clarkson.edu/programs/goia_group

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Instrumentation:

• SEM / FE-SEM• HRTEM / STEM• Particle sizing – Laser diffraction

– Dynamic light scattering• BET surface area and pore analyzer• Thermogravimetric analyzer (TGA)• Thermomechanical analyzer (TMA)• UV-Vis spectrophotometer• Powder X-ray diffraction analyzer• Zeta potential analyzer• Energy dispersive X – ray spectroscopy (EDX)• Inkjet printer• Profilometer• Viscometer• Attritor / mixers

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Why colloids?

– Colloid from “Kolla, Kolloid” – glue in ancient Greek.– Mixture where one component (e.g. particles) is dispersed evenly throughout another (e.g. solution).

e.g. milk, paint, ink, cosmetics, blood, smoke, styrofoam, mist, etc.

Why metal particles?

• Electronics• Catalysis• Metallurgy• Pigments• Medicine & Biology• Transparent conductive coatings• High density storage• Obscurant smokes

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Typical preparation approaches:

Phase break Phase break –– downdown- milling / grinding- atomization

Phase transformationPhase transformation- pirolysis / thermolysis- reduction

Phase build Phase build –– upup- condensation in gas phase- condensation in liquid phase

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CLUSTERS

METAL IONS / COMPLEXES

METAL ATOMS

Reduction

NANOSIZEPRIMARY PARTICLES

Diffusional growthNUCLEI (~8-10Å)

POLYCRYSTALLINEPARTICLES

CRYSTALLINEPARTICLES

Diffusional growth Aggregation

STABLENANOSYSTEMS

Me n+ + Red m- ⇔ Me0 + Ox m-n

ΔE0 = E01 - E0

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ΔG0 = -nFΔE0

D. V. Goia: Preparation and formation mechanisms of uniform metallic particles in homogeneous solutionsJ. Mater. Chem. 14, 2004. pp. 451-458

Chemical precipitation:

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Properties of metal particles:

• Size and size distribution• Dispersion• Internal structure (crystalline, polycrystalline)• Internal composition • Morphology• Surface properties

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Wet film

Dry film

Sintered film

Drying

“Burn-out”

Sintering

“Clean” film

Industrial Applications:•MLCC

•Resistors

•Solar Cells / Panels

•Plastic Electronics

•Radio Frequency I.D. Tags

•Displays

Paste Deposition:•flexography•spin coating

•screen printing•ink-jet printing

Preparation of metallic layers via thick – film technology

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Multilayer ceramic capacitor (MLCC)

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Fe(II) – citrate

complex

CuCl

dispersion

Simple, cheap, ‘clean’ method< 30$ / 1 Kg pure Copper

- Patented by E.I. DuPont de Nemours and Company

Synthesis of Cu particles

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Cu particles

~1.5µm ~0.5µm20oC 60oC

- Patented by E.I. DuPont de Nemours and Company

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0.01 0.1 1 10 100 1000 100000

2

4

6

8

10

12

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Vol

ume

(%)

Size (μm)

D (0.5) = 2.2 μm

Degree of dispersion (PSD)

Tap density > 3.5 g/cc

- Patented by E.I. DuPont de Nemours and Company

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Crystallinity (XRD)

30 40 50 60 70 80 90 100

1000

2000

3000

4000

5000

Inte

nsity

(a.u

.)

2 theta (degrees)

88 90 92

200

400

600

800

1000

Inte

nsity

(a.u

.)

2 theta (degrees)

24nm60

42nm20

Crystallite sizeTemperature ( oC)

- Patented by E.I. DuPont de Nemours and Company

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100 200 300 400 500 600 70098.0

98.5

99.0

99.5

100.0

100.5

101.0

101.5

102.0

Wei

ght (

%)

Temperature (oC)

Δ = ~ 0.49 %

0 200 400 600 800

100

105

110

115

120

125

Δ=24.36%

Wei

ght (

%)

Temperature (oC)

Purity and oxidation

in 5%H2 / 95%N2 in air

- Patented by E.I. DuPont de Nemours and Company

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Sintering of Cu particles

100 200 300 400 500 600 700 800 900-10

-8

-6

-4

-2

0

2

4

6

8

10

D

imen

sion

Cha

nge

(%)

Temperature (oC)

Commercial powder Precipitated powder

- Patented by E.I. DuPont de Nemours and Company

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Cu particles

~0.3µm ~1.5µm

- Patented by E.I. DuPont de Nemours and Company

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Conclusions

Chemical precipitation is a versatile technique, offering many ways to control synthetic processes.

Understanding the mechanisms and parameters controlling the formation of metallic particles offers the capability to yield dispersed uniform Cu particles with controlled morphology.

The particle size is varied in a broad range (0.3 to 1.5 µm) without altering their uniformity and dispersity.

The simplicity of the process and the high concentration of metal make the described process an advantageous route to manufacture cost effectively in large scale dispersed copper particles for applications in electronic industry.

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FundingAdvisors:Prof. Dan V. Goia (Chemistry)Prof. Vladimir Privman (Physics)

Collaborators (students / postdocs):Dr. D.T. Robb (Berry College - GA)Dr. D. AndreescuDr. M. Jitianu (Rutgers University)Dr. R.K. Roy (Indian association for the cultivation of science)C. GoiaS. Chevalliot (University of Cincinnati)S. Reiche (Max Planck Institute - Berlin)D. Le (University of North Carolina at Chapel Hill)I. SevonkaevB. FarrellK. BalantrapuB. MorrowS. LaPlanteL. LuN. PorterW. Olson (General Electric)G. Burkey

www.clarkson.edu/programs/goia_group

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Thank you !Thank you !