Issue link: https://iconnect007.uberflip.com/i/1269815
40 PCB007 MAGAZINE I JUNE 2020 Not to date myself, but back in those days a design with a 125-micron (5-mil) line and space on flex or rigid materials was pushing technology limits. Today, PCB fabricators are manufacturing designs with 25-micron (1-mil) line and space. In fact, most of us are using smartphones with PCBs with 30-micron trace and space. These extremely high-volume, com- mercial designs are produced using mSAP or modified semi-additive technology. This pro- cess starts with a very thin layer of copper foil and uses an additive rather than a subtractive chemistry process to create the circuit pattern. Fabricators offering mSAP technology typically serve very high-volume requirements, and the process requires significant capital investment. Market dynamics in the electronics indus- try are quickly changing. Today, it is not only high-volume applications that are being driv- en to the need for 25-micron trace and space. Additive and Subtractive: When Opposites Attract The majority of my career has been spent working in the PCB industry. Like many, I landed here "by accident." Fresh out of col- lege with a brand-new economics degree, I was looking for a position in finance and was offered a position in accounting and human re- sources in a small flexible circuit manufactur- ing company. Honestly, I did not even know what a flex circuit was, so they were truly tak- ing a risk with me. My initial training there was not in accounting; it was in manufactur- ing, spending time working on the product, and learning the processes so that I would be better able to understand what I was doing when I did start working in accounting. The manufacturing processes I learned during that time were the traditional subtractive etch pro- cesses, essentially starting with copper lami- nate and etching away the unwanted copper to create the designed circuit pattern. Flex Talk Feature Column by Tara Dunn, OMNI PCB