Issue link: https://iconnect007.uberflip.com/i/374650
54 The PCB Magazine • September 2014 What is eSurface? eSurface is an additive (or embedded) pro- cess that may change the way many circuit boards are manufactured—particularly HDI boards and high-performance boards that are built for speed and require the highest levels of signal integrity. The inventor of eSurface is Dr. William Wismann. He developed a liquid co- valent bond that reduces over a dozen steps of current subtractive technology, down to these three steps: • eSurface covalent bond is applied directly to unclad substrate • The coated panel goes directly into a standard or LDI photo imaging unit, followed by a water rinse and dry • The panel then goes directly into an electroless-plating tank The first and most obvious benefit of eSur- face is that it eliminates processes. No dry-film photo resist, no more developing solution, no more plating conditioners, etchants or waste treatment—making it cheaper, environmental- ly friendly, and capable of trace widths down to 1–2 mils, while offering increased yields. Cheaper, faster, smaller, cleaner; it's a PCB fab- ricator's dream! Additive or Embedded? After watching several live demos of the eS- urface process at their lab in Carlsbad, Califor- nia, and after looking at multiple panels under a high-powered microscope on a huge monitor, I understand why the leaders at eSurface hesitate to call this an additive process. It needs its own category, due to the fact that the chemistry is absorbed into the pores of the substrate and the copper displaces the chemistry there, embedding it (at an atomic and microscopic level) and caus - ing the substrate and copper to share electrons, thereby locking the metal in place. What this means practically is that the peel strength is out- standing—far better than panels laminated with copper foil from substrate manufacturers. Fur- thermore, even if we could reliably produce 1–2 mil traces through current print and etch tech- nology, the fragile traces are easily wiped away with a brush of your hand. There's simply not enough adhesive left beneath that trace to hold it securely in place. I cringed when Vice President of Strategic Operations Alex Richardson took a car key to a 1mil trace—and then I was stunned to see it remain fully intact! Though the trace was understandably marred, the trace was unmoved. So far, I have explained how eSurface has made the impossible possible by offering the following: • Chemistry that enables direct imaging and plating to bare substrates while eliminating the side effects of etching (such as over or under-etching and inconsistent trace geometries) • The elimination of multiple process steps that save time and money • The ability to offer HDI and robust fine features, with relative ease and cost- effectiveness for the first time in our industry's history • Unprecedented bond/peel strength • Water-soluble chemistry that can go right down city drains, offering us an environmentally friendly solution for our customers and ourselves In addition to: • Traces, pads, and holes are plated simultaneously offering homogenous plating surfaces, which eliminate many issues that arise from the current 2-step plating process—particularly around the hole-knee • Any electroless metal can be plated directly to the substrate (i.e., copper, silver, tin or gold) • Nearly all capital equipment required is already present in most PCB facilities. The only additions needed are two retrofit pieces of equipment from Chemcut and Austin American, which are relatively minor investments • Conductor and feature geometries that are pristinely crisp and consistent and will certainly offer better signal integrity • 3D products and features that can now be easily printed and plated. We are no longer limited to planar, 2D surfaces MAKING THE IMPOSSIBLE POSSIBLE continues