Press Release

Printed Electronics: The Next Generation of PCBs?

The next generation of printed circuits may be totally different than what we produce now.

To evolve into a greener, higher-density product, the printed circuit board may well become just that: Printed. New nano silver and copper powders, combined with advanced nano ceramic-based photoimageable dielectrics, will be a force to contend with.
'But this is still years away,' you say? No, these technologies exist today. I have made prototypes this way, protos that were fully functional at first test.

The technology is not new, but the materials are. Imagine manufacturing a complicated fine line (2 mil) 10-layer HDI board with no drills, no plating, etching, stripping, dryfilm, lamination press, scrubbers, deburr, electroless, plasma or waste treatment. And imagine producing such a circuit in hours, not days.

This technology is here now, awaiting adventurous companies unafraid to proceed into the next generation of PCBs. The basic idea: A layer of photoimagable dielectric is laid down and exposed along with the traces. After a short semi-cure, nano silver or copper ink is squeegeed into the opening and the surface is cleaned, which creates the traces. Then there's another short semi-cure oven cycle.

The next dielectric layer is layered down and imaged and developed, and again the silver ink is squeegeed in, producing short, free square traces with very defined edges and lines. The layering and filling with silver, gold or copper ink continues till the circuit is finished and a final full cure is performed. The printed circuit can be placed on just about any material: FR-4, a semi-finished FR-4 board, flex material, waterproof paper, cloth, plastic or glass. This works on almost any surface that can withstand 180 ºC.

There are many possibilities for the makeup of the conductive ink, normal silver or copper ink, or the new nano particle copper and silver inks. Printed electronics technology is quick to manufacture and is especially green when compared to traditional PCB fabrication with its plating tanks, machines and processes. The carbon footprint of a new printed electronics manufacturing facility is a small percentage of the size of a normal PCB facility, with considerably less waste generated and considerably less equipment and processes to buy, maintain and worry about.

Reliability has been tested and explored, but as with any new technology, one must be aware of future ramifications. All the testing so far has shown the new nano ceramic dielectric layer to be superior or equal to FR-4, with low moisture absorption, a high number of solder cycles (18), long thermal life cycles (> 2,000), and a large dielectric (2,000 volts per mil) rating. One big advantage is that the dielectric material's ceramic, silica, boron and alumina composite base has a higher thermal conductivity. The dielectric layer can be screened, rolled or curtain-coat applied. So far I have used screened and rolled, with both performing well, laying down a 1 mil layer each time.

Many companies are researching ways to apply the conductive traces using inkjet printer heads. This has potential for the future of our industry, although the advancement may hurt us just like the laser color copier hurt the printing business. Any local corner store can produce great looking brochures and printed goods quicker and cheaper than any printer could.

We may well see the advent of small desktop PCB manufacturing units that can inkjet print your PCB while you wait. You'll simply inkjet a dielectric layer and create plating-like technology by laying down a second conductive layer interconnection. We may very well be able to produce very sophisticated circuits, all in a desktop unit.
But, you say, 'This will never replace our everyday printed circuit board.'

Yes it can, and it will. To manufacture a multilayer through-hole board, an FR-4 core with middle layers would be processed normally, and the outer 2-30 layers added with the printed method. Don't be so surprised. Any mature, dated product like the PCB--one that has been manufactured the same way for 40 years--is due for a technology update.

The new kid on the block is greener, less wasteful, faster, better, thinner, able to create smaller lines and--most importantly--less expensive. Printed electronics is not a new invention, just a reinvention of existing technologies. Anyone ready to step up and advance into the 22nd century?