Issue link: https://iconnect007.uberflip.com/i/1471044
46 PCB007 MAGAZINE I JUNE 2022 We had nitrate-free silver, which builds up about 10–15 microinches of silver in five min- utes, so we tried simple tests with it. To our sur- prise, it solved all their issues, and they became an instant customer for this silver. ey had had ongoing champagne voids and line reduc- tion issues, and this silver solved that for them. Strong on that success, we made a few instal- lations where those issues were identified. As I mentioned, the silver market was slow, and we did not push because we did not know of any corrosion benefit yet. e nitrate-based pro- cess can deposit up to 20–30 microinches in one minute, and for us, that is the main issue. We felt that thinner, pore-free silver had to be better than thicker, fast deposited silver. We had in mind to do a side-by-side bench comparison of these two silvers. e nitrate base is still dominating the market and is also directly related to the minuscule market share of silver as a final finish. en the pandemic hit, and I had a lot of free time to involve myself in that long-desired bench comparison study. Some material manufacturers had begun to share their findings on 5G requirements and, based on the requirements of high-frequency PCBs, it looked like silver was the way to go. To make a long story short, high frequencies travel on the surface, and silver is practically as good as copper at precluding signal loss. Signal loss was the main problem for 5G applications as the component will stop working. Compensating for insertion loss requires a more sophisticated material, or heat-resistant components, or signal boosters, all of which lead to higher costs to accommodate ENIG. Or you could use alkaline nitrate-free immer- sion silver, at no extra cost. In this world, ENIG is the worst conductor due to its thickness and magnetic properties (Figure 1). Figure 1: A comparison of various final finishes.