Issue link: https://iconnect007.uberflip.com/i/834021
8 The PCB Magazine • June 2017 In the early '80s, the PCB company I worked for was testing some of the first material for bur- ied resistors. I can't recall what customer it was for, or how far along the project got, but over the years it seemed like the technology was slow to be adopted and perhaps ahead of its time. Now, a lot of years later, embedded technology seems to be finally coming into its own—thanks to Moore's Law and the ever-pressing need for more real estate on the circuit board surface. No longer just for the odd, expensive military product, bur - ied components can be found in that most ubiq- uitous of consumer products, the smartphone, as you will learn in this issue. Who knew! Back then, there were only buried resistors and from what I understand, the material was not cheap. Most uses involved either a need for extraordinary reliability or there was enough sav - ings in reduced layers or improved abilities that would justify the cost. But there are other types of passives as well as buried active components. And the justifications are more complicated: sig - nal integrity, greatly improved imaging capabil- ity which means more accurate resistive values, and always space, as in the required surface area of a circuit board. We thought we would find out from our readers just how "popular" this technology real- ly was. After all, as circuits get denser and lines/ spaces get smaller, it stands to reason that bury- ing components would be an increasing require- ment and they would be part of every complicat- ed multilayer. From our recent survey, we learned that more than half the respondents saw ver y lit- tle embedded technology work and about 5% worked with it a great deal (<75% of their work). So that leaves roughly 40% working with bur- ied technology some amount of the time. When asked what type, the answers were fairly evenly divided between resistance, capacitance and ac- tive components. W e were curious as to the reasons for using embedded technology and got a wide variety of responses. The three main reasons were to free up board real estate, increase active circuit densi - ty, and to improve electrical performance. To im- prove reliability and to reduce cost were a little lower on the list but significant (Table 1). by Patty Goldman I-CONNECT007 Embedded Technology: It's All Around Us PATTY'S PERSPECTIVE