Reading time ( words)
In the early ‘80s, the PCB company I worked for was testing some of the first material for buried 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, buried components can be found in that most ubiquitous 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 savings 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: signal integrity, greatly improved imaging capability 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 really was. After all, as circuits get denser and lines/ spaces get smaller, it stands to reason that burying components would be an increasing requirement and they would be part of every complicated multilayer. From our recent survey, we learned that more than half the respondents saw very little embedded technology work and about 5% worked with it a great deal (
To read the full version of this article which appeared in the June 2017 issue of The PCB Magazine, click here.