Issue link: https://iconnect007.uberflip.com/i/291105
86 The PCB Magazine • April 2014 Padmani the "Cowboys," because they con- tinually head into uncharted technological ter- ritory to meet our customer's needs. Despite our pioneering spirits, however, I find myself wondering about where we can go from here to meet ever-increasing speeds and ever-lowering toleranc es that can't be held consistently due to the inherent limitations of the PCB manufacturing process. Let's face it, even on a good day, neither plating nor etching is an exact science—which is why there are tolerances in the first place. With increasing frequency I am asked if we can hold line width/spacing to 1 mil toler - ance or less. The speed of the chips running on these boards is screaming fast and the lami- nate, finishes, conductors and connectors are slowing these racehorses down. Engineers are searching everywhere possible to eke out a little more speed or performance. Meanwhile, ev- ery point along the supply chain is looking to save a buck. So in short—people want unprecedented precision, consistently and dirt cheap! After I blogged about this issue recently, a retired engineer said he could achieve those tolerances 30 years ago and wondered why things hadn't progressed. Well, he was referring to a time when he worked for a large R&D com- pany that had an almost limitless budget and a small army of engineers to make that happen. They developed custom tools and equipment.. As we all know, those days are sadly gone and progress is certainly impeded by today's limited budgets. Laminate manufacturers, like Rogers Corp. and Taconic, who make advance circuit materi- als for high-speed applications, continually ad- vance in producing lower-loss materials, bond ply and adhesives. Progress is also being made on connectors and points of connection to al- low signals to flow freely. Currently, it seems like PCB fabricators are the weakest link—con- strained by the limits of the manufacturing pro- cess itself. I believe part of the solution may lie in a closer working relationship between designers and their board suppliers. When a designer thor- oughly understands the manufacturing process, adjustments can be made during the design phase, which may aid in reliability, consistency and price. Due to economic constraints, many RF engineers are being called upon to lay out their boards without the help of a formally trained PCB designer. Some of these indi- viduals understand the manu- facturing process, and some do not. This creates a disconnect between the intent of the de- sign and the realities of board fabrication. Due to the current state of the industry, we are all being called upon to wear more hats—putting a strain on time and available funds. How- ever, the investment in collab- orative time is crucial to long term success and cost control. The demand for RF/micro- wave and high-performance boards is growing on both the commercial and military front. It seems to me that we are ripe for some breakthroughs that will enable us to produce boards that will aid, rather than hold back, the current generation of high speed chips. Perhaps technologies such as 3D printing will become a viable solution down the road. Whatever the case may be, I am sure we will one day look back with nostalgia, as I now do the Olympics. Then we will recall these days in which we faced these obstacles, transcended them and then pulled off our own version of a perfect triple Lutz. PCB Judy warner is the director of sales and marketing for transline technology, a pcB manufacturer specializing in rF and microwave applica- tions in anaheim california. to contact warner, or to read past columns, click here. Engineers are searching everywhere possible to eke out a little more speed or performance. Meanwhile, every point along the supply chain is looking to save a buck. So in short—people want unprecedented precision, consistently and dirt cheap! " " THE CONUNDRUM OF RF/MICROWAVE AND HIGH-PERFORMANCE PCBS continues