The PCB Design Magazine

PCBD-Apr2017

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34 The PCB Design Magazine • April 2017 technologies: not just MEMS mi- crophones but other MEMS devices and technologies. The third area of use where we see growing opportunities are in heater designs. Heater elements are used for things like semi-active la- ser activation of smart munitions or embedded resistors as heater el- ements in a printed circuit board to maintain surface components at optimum temperatures for op- timum operation, whether that's in deep-space applications or even down to earth in medical diagnos- tic type applications. OhmegaPly has also been used as an internal heater in burn-in boards to allow for IC burn-in without the need of a tem- perature chamber. Shaughnessy: Does this work at RF speeds? Mahler: Yes, absolutely. In fact, many of our ap- plications in the gigahertz range are mostly us- ing our product as a replacement of chip resis- tors in power dividers. In that case, we're using low dielectric constant materials like traditional PTFE materials that Rogers, Arlon and Taconic supply. We see a growing trend, both in high- er speed and higher performance, as well as in very, very fine-line modules, chip carrier and those kinds of areas of applications to use low- er dielectric constant, low-loss dielectrics from Rogers and Arlon and Taconic as well as materi- als from companies like Panasonic and Isola. Because the resistor material is essentially inductor-free; we remove a lot of the parasitics coming off a board to make it very attractive at higher frequencies of operations. Line termina- tion in very high-density IO is also an attractive use of the technology by a lot of our end-users, especially in the next generation of memory and in chip carriers and IC carrier modules. In these cases, we, are looking at extremely fine line circuits, resistors built within traces of 50 micron, 40 micron, and even narrower. We're talking about extremely small resis- tors, and the ability to image and etch those ac- curately is very critical, so we see that the kind of copper being used is getting thinner, and now we're offering a 12-micron along with our standard 18-micron copper. We're also working with a five micron, and ultimately a three- micron copper on a peelable copper carrier. In addition, we're starting to supply lower-profile coppers as well so you have not only better performance at the high-frequency gigahertz range for microwave type applications, but the lower-profile copper also adds in the accuracy with the imaging and etching pro- cess of line traces, which ultimately mean more accurate resistive ele- ments as well. For that reason, we see a growing trend in our industry for thinner coppers, lower-profile coppers, new dielectric materials with lower loss and lower dielectric constants and capable at operating effectively at higher frequency. Shaughnessy: What do you see going on in ad- vanced materials that's really caught your eye? Mahler: In advanced materials, our area of fo- cus is the development of products which are more accurate, on thinner and very, very low- profile coppers with good adhesion, and also ul- timately with tighter resistive value tolerances. I think that when it comes to the dielectric types that we're seeing, as I mentioned before, the development of low-loss materials; it's not just PTFEs but also a lot of the other polymers that are being developed today. We all have exacting standards. You want something that is halogen-free. You want things that can handle lead-free assembly. You want things that can environmentally meet all compliances, REACH and RoHS and all the rest. Really what you're looking at is material that operates very effectively at the higher frequen- cies; data rates are increasing, and ICs are going a lot faster, which means more of a need for our product for things like termination. In addition, see more and more applications for, again, heater elements. Our product as a re- sistor can heat up and because of that you want to have dielectric type materials that have good thermal conductivity. Along with the lower di- BRUCE MAHLER DISCUSSES OHMEGA'S RESISTIVE MATERIAL TECHNOLOGY Bruce Mahler

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