Issue link: https://iconnect007.uberflip.com/i/1467744
MAY 2022 I PCB007 MAGAZINE 67 get certain loss properties and combinations that are attractive, both for performance and cost. You don't always need to use the most costly option. Johnson: is starts to sound pretty custom- ized. Kelley: We want to offer our customers the best cost-performance combination that they're looking for, but we also need to be able to sup- ply in volumes. We don't want a lot of change- overs between one resin system and another in our process because it's very disruptive. If we have the same resin, but we can use different combinations of glass and copper, there is min- imal impact to operational efficiencies. We can offer combinations that satisfy customer needs for cost and performance, and we can manu- facture at high volume with relatively short lead time. Johnson: is customization results in a lot of options, and the one you choose will affect the overall performance of your design. Nowadays, the material—the substrate itself—becomes a key part of the specification of your design, more than it ever was before. Now you have to specify the material as well as component val- ues in the design process to get a certain kind reliability testing. e CAF resis- tance we're seeing is excellent. In fact, with these very smooth cop- per foils for high frequency appli- cations, we've seen cases of copper migration at the bond line between an etched laminate surface and the prepreg that's bonded to it. Traditionally with CAF, people think of migration along the resin- to-glass interface, which is the most common failure. With some of these very low-profile copper foils, the copper suppliers are determining how to get a better chemical bond vs. mechanical bond between the copper and dielectric. ere are various adhe- sion promoters that can be used, but some may not be compatible with all the resin systems that companies like us are trying to develop. If you use the wrong adhesion promoter, when you etch off the copper it may still be on the surface and interfere with the bond of the prepreg to the etched laminate. We've spent considerable time making sure we understand what's driving that and what we need for the right adhesion promoter for our resin system. As we wrap up that work, we are seeing some very good results. Even as we introduce this new product, we're looking at what comes next. Our chem- ists are looking to synthesize some of our own polymers, which would still be used in com- bination with commercially available resins, but may offer us some unique attributes in our applications. As we develop resin systems, we recognize there is a range of operating frequencies to consider, and you don't always need the low- est loss material. When you don't, you don't want to pay for the loss performance you don't need. We are offering a halogen-free resin sys- tem which is extremely low loss, but we could put it on E-glass, low Dk glass, next-generation low Dk glass, and different copper combina- tions. With that one resin system, we can tar- Thermal analysis equipment in the new facility.