Tag Archives: nanomaterial

Holding it all together

microcircuit

When I was a kid, I loved tearing up stuff to see what was inside it.  I guess that’s just a normal guy thing, sort of like spitting off bridges or something.

Electronic devices had especially cool guts back in the day.  First there were tube radios that came with that eerie, 1950s sci-fi glow.  The tubes themselves were pretty cool, filled with all sorts of little metal screens and such.  Those were replaced by transistor radios which were less sci-fi but much more futuristic.

Today, I don’t get much pleasure out of tearing up stuff because all the innards are so integrated into modules that there is no longer anything interesting to look at.

Anyway, the point of this meandering reminesce is really to talk about what holds all those parts together.  In the old days, it was wires.  You could see them.  They were eventually replaced by printed circuit boards with flat metal traces instead of wires.  Now, even the connecting traces are often buried deep down in the circuit boards, or, even worse, designed into the silicon chips themselves.

But whether wires or traces or silicon pathways, something has to hold it all together, and that something has always been solder.  However, if VT Corporate Research Center company NBE Tech has it’s way, solder might be replaced by a new material made from silver nanoparticles.

Elimination of lead based solders has been a goal for many years.  Other types of solders can be used but the perfect combination of processing temperature and performance has not always been possible.  Investigation continues into other bonding methods, such as low temperature and pressure sintering of precious metals.  The new NBTech nanomaterial provides a way to bond semiconductor dice to substrates without solder, simply by applying a small pressure while simultaneously applying a relatively low temperature just over 200 degrees C.

NBE founder GQ Lu invented the material and then set up a company to commercialize it based on a license from Virginia Tech Intellectual Properties.  Since then he has worked to improve the performance and develop a manufacturing process suitable for commercial application.  He recently received an independent verification of the value of his invention by the Fraunhofer Institute.  Researchers there published a paper last fall that indicates sintered bonding using the nanomaterial paste produced stunningly better performance that solder-based attachments.  In one test, nanomaterial and solder bonded parts were subjected to heating/cooling cycles of 45-175 degrees C.  Using the data obtained, it was projected that the sintered parts would withstand up to 160 million cycles, where the soldered components failed after 40,000 cycles.

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Filed under Communications, electronics, Materials, Wireless