Jetting fluids in non-traditional packaging and assembly applications
Figure 11: Jetted Carbon Ink
Figure 12: Nafion on catalyst Ink
Jim Klocke, who developed the jet and
process technology for carbon ink and
Nafion dispensing.
references
1. Peter N. Pintauro and Ryszard Wycisk,
Department of Chemical Engineer-
ing, Case Western Reserve University,
“Polymeric Membranes for Fuel Cells:
Overview and Future Outlook”
Figure 12. Nafion on catalyst ink.
2. G. Q. Lu, C. Y. Wang, Penn State
Figure 11. Jetted carbon ink.
Univ. “Electrochemical and flow char-
acterization of a direct methanol fuel
side its bounds or not wet a particular area.
passes that do not crack but also meet the
cell”, Journal of Power Sources, 134
As the Nafion dries, the outer edges dry
throughput needs (Figure 11).
(2004) pp 33-40.
first; this creates a film layer that looks like
Also, the automated dispenser should
3. J. Santander, N. Sabate, N. Torres, J. P.
a bathtub. This problem can be mitigated
have a mass flow calibration function to
Esquivel, I. Gracia, P. Ivanov, L. Fon-
by using a dam and fill technique. There
keep adequate control on the amount
seca & C. Cane, Centro Nacional De
are a multitude of patterns that must be
of ink that is applied—catalyst density is
Microelectronica (CNM-1MB), CSIC,
empirically determined as different formu-
important for good fuel cell operation.
Bellaterra, Spain, “Towards a Mono-
lations of Nafion/solvent present different
Most of the inks also contain a small
lithic Micro Direct Methanol Fuel
drying characteristics. The automated
amount of Nafion, requiring the wetted
Cell”, IEEE Sensors 2008 Conference,
dispenser should offer an easy means to
parts of the jet valves to be passivated.
1-4244-2581, pp 37-40.
fill the desired shape to keep the bathtub
Standard ink jet heads available in the
4. Agilent Technologies, Semiconductor
shape to a minimum and keep the inner
market cannot be adequately passivated for
Manufacturing Technology – Elite
surface flat. By using different patterns of
long term use, which is another limiting
Development, “A Silicon-based Air-
fill a dry film, thickness of 30 microns ±
factor for standard ink jets.
breathing Micro Direct Methanol Fuel
5 microns is possible. Figure 12 shows wet
Nafion application has challenges in
Cell using MEMS technology. pp1-10
Nafion on carbon ink catalyst layer and Fig-
dispensing as well as the after-dispensing
5. Xiaowei Liu, Chunguang Suo, Yufeng
ure 13 shows a typical dry Nafion profile.
surface interactions. Since the Nafion
Zhang, Haifeng Shang, Weiping Chen,
solution is volatile, the jet valve must
Xuebin Lu, “Application of MEMS
conclusions
be managed properly by the automated
Technology to Micro Direct Methanol
The ability to jet adhesives has enabled
dispenser so the nozzles do not plug with
Fuel Cell”, DTIP of MEMS and MO-
new semiconductor packaging processes.
cured Nafion. The jets’ wetted parts must
EMS, Stresa, Italy, 26-28 April 2006.
The ability to jet silver epoxy along a
be a material set that is highly compatible
6. G. Q. Lu, C. Y. Wang, T. J. Yen, X.
stepped edge provides a cost-effective
with sulfonic acid.
Zhang, Penn State Univ. “Develop-
method to stack eight or more die.
Once the valve and automated dis-
ment and Characterization of a Silicon-
Semiconductor devices are moving
penser are adequately configured, the de-
Based Micro Direct Methanol Fuel
out of the traditional market of being just
position of the Nafion presents new issues.
Cell”, Electrochimica Acta 49 (2004)
integrated circuits. In life science markets,
The typical cured PEM layer of Nafion is
pp821-828.
the integrated circuit of a sensor has a
between 30 to 100 microns thick, depend-
7. Didier Marsacq, “Micro-Fuel Cells”,
dispensed reagent as an active part of the
ing on the fuel cell design. If the Nafion is
Technical Research Division, CEA
circuit.
dispensed in one film pass, it may flow out-
Grenoble Center.
Figure 13: Nafion Profile Semiconductor processes are enabling
8. Horatio Quinones, Brian Sawatzky,
new applications further outside the
Expanded Z axis scale et al, Asymtek, “Silicone-Phosphor
traditional use of wafer processing. The
Encapsulation for High Power White
mDMFC could not exist without using
LEDs”, SMTA, Pan Pacific Confer-
semiconductor conductive layer deposi-
ence, 2008
tion and etching processes. Furthermore,
9. DuPont Displays
dispensing of liquids such as catalyst inks
10. Vertical Circuits Inc.
and Nafion PEMs enable the end device
to function as a fuel cell. The part of the
package that is dispensed is a functional
Thickness : 40 microns +/-5 Alec J. Babiarz is president, new business
part of the end device.
development at Asymtek. An Asymtek founder,
The applications for jetting fluids keep
he is co-developer of three patents dealing with
increasing and enabling new products,
equipment and apparatus for fluid dispensing
which further the expansion of semicon-
and is the author of many articles on the topic.
ductors outside integrated circuits.
Mr. Babiarz earned a BSE from Arizona State
University and two master’s degrees (MSME
acknowledgements
and MSEE) from Stanford University. Prior to
Asymtek New Business Development
establishing Asymtek, he was a project manager
Team: Don La, Dave Mejia, Brian Sa-
Figure 13. Nafion profile.
at Hewlett-Packard Co., working on inkjet
watzky, Able Gomez, Rick Horwath and
technology for printers and plotters.
18 – Global SMT & Packaging – May 2009
www.globalsmt.net
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