This organization seeks printing technology to produce higher-current miniature circuitry. Approaches of interest include reducing use of expensive inks, eliminating a plating step, and increasing adhesion to a variety of substrates. An additional area of interest is to enable multilayer structures for more complex circuitry.
Details of the Technology Call
Applying print technologies such as inkjet to circuitry offers rapid prototyping and potentially inexpensive production opportunities for many electronic devices that range from RFID tags, through intelligent cables, to flexible displays and touch screens.
Currently, this company prints their circuitry using a relatively low-viscosity ink that incorporates silver nanoparticles. They print in a single layer -- with some adhesion difficulties, depending on substrate -- and then electroplate on top of that in order to provide a trace that can handle higher currents. They are aware of several printing technologies that may be adapted to the process, such as variations on inkjet, metal-jet, gravure, screen, stencil, and laser transfer printing, each of which has advantages and drawbacks.
They are looking for several possible technological answers:
o An alternate ink material that may have lower viscosity but that can produce the trace thickness capable of handling sufficient current.
o Higher silver loadings (on the order of 40-60%).
o An inexpensive seed ink that could be electroplated (or used with electroless deposit) and then electroplated afterwards, but where the seed is much less expensive than the silver currently used. Finished thickness needs to be in the range of 50-70 microns.
Key characteristics include good adhesion to a variety of substrates, including dielectrics and polymers including flexible substrates, as well as the usual properties of good ink: jettable, small drop volumes, and excellent control over surface tension and viscosity.
o The ability to print thicker traces to handle higher currents.
o The ability to print multiple layers. Currently, later passes disturb traces laid down by earlier passes.
o Higher silver loadings for the ink, or a different seed technology that is less expensive than silver.
o Excellent control over surface tension and viscosity.
POSSIBLE SOLUTION AREAS
Nano- and nano-assembler technologies