Incumbent technology takes a long, long time to displace. Just look at all the through-hole components still consuming board real estate today.
It should come as no surprise, then, to learn that printed electronics have been around nearly 30 years. And even though few traditional electronics manufacturers – read: fabricators or assemblers – are building printed electronics today, the total market, according to IDTechEx, will reach a tidy $26.5 billion in 2016.
Granted, that sum includes printed, flexible and organic electronics, and the majority of that is OLEDs, says the research firm. And although OLEDs are often deposited on flexible substrates, when the subject of PE is broached, it generally refers to components such as diodes, sensors and batteries, not conductors on boards.
Recent events suggest that could be primed to change.
Printed electronic technologies – be it screen, inkjet, gravure (engraved) or some other method – are finally reaching the point where the capability and cost could drive simpler and cheaper manufacturing processes.
Hobbyists (also known as “makers”) have jumped on the technology. Various R&D and academia labs are also using it, generally for prototypes, often because of the simplicity and cost. Desktop 3D printers are coming out of the woodwork.
Additive processes have long been seen as the Holy Grail of plating conductors for a host of reasons: less material cost, less waste, less process time, less equipment expense.
Some manufacturers are now able to produce not only small yet electrically robust lines and spaces on a variety of substrates, but they have gone so far as to embed transistors, diodes and antennas. PE will be an enabler of greater levels of embedded technologies, with all the resultant reduction in processing steps and time coupled with greater reliability as the parts are better protected from the external environment.
Much of the current attention appears to be on electronic sensors, where the market is still skimming the surface of what could be possible. Ahmed A. Busnaina, Ph.D., is a former semiconductor executive who now runs a lab at the NSF Nano Center of Northeastern University in Boston. He says sales of IoT hardware are forecast to reach $500 billion by 2024, and sensors, which are predominant in IoT, will grow more than 250% over roughly the same period to reach $64.3 billion.
Speaking at the New England IMAPS meeting in May, Dr. Busnaina said nanoscale offset printing could be a game-changer for producing electronic sensors, as it is capable of producing 20µ micron or smaller line widths, and interconnecting multilayers through the board, as opposed to simply printing in the X axis on top of a substrate. Offset printing could slash state-of-the-art semiconductor fab costs from billions to under $100 million, he added.
While Jabil, Flex and other EMS powerhouses are working diligently on printed electronics, primarily in pursuit of the aforementioned lucrative IoT and wearables markets, I would argue board fabricators are in prime position to take advantage of the emerging technology.
For starters, the process steps are consistent with what fabs are familiar with: screen printing or direct-write of conductive material, followed by an IR or UV cure. Second, the equipment cost is coming down, an important precursor, given that most fabricators today are small and have limited access to capital. PE fits well with current trends toward environmentally friendly manufacturing, especially given the high cost of processing and reclaiming large volumes of copper and other metals used in PCB fabrication.
Perhaps most important, fabricators, particularly in the West, are in dire need of an innovation leap. PE represents an opportunity to level the playing field, especially now that high-rel users such as NASA are giving it a serious look.
There are roadblocks. Much of the ink technology has centered on silver, which is expensive and prone to whiskering. According to Optomec, a developer of aerosol-jetting PE equipment, nanoparticle materials of less than 1µm are needed, preferably with a metals content approximating 70%. Solder and other material suppliers will need to invest in R&D. (Promotion alert! Jabil and Optomec are among the speakers at the Evolving Technologies session I helped coordinate for the SMTAI program this fall.)
As for those emerging technologies, those who are bullish on PE might want to keep an eye on what could be next: Ohio State researchers have successfully embroidered circuits into fabric with 0.1mm precision – the perfect size to integrate electronic components such as sensors and computer memory devices into clothing. Talk about wearables.