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58 PCB007 MAGAZINE I MAY 2023 Electroplating has always been at the core of printed circuit fabrication. It was the first pro- cess I was assigned to as a young engineer at Hewlett-Packard in 1970. Of course, the cop- per-plating process was copper pyrophos- phate, an alkaline solution—a very temper- amental bath from MT Chemicals Inc. Soon aer I mastered the chemistry and control of this plating solution, I had the opportunity to test and introduce PC-GLEEM from LeaRonal, Inc., a new sulfuric acid-based copper sulfate copper-plating chemistry. We never switched back. e technical editor at CircuiTree was Karl Dietz, who wrote many Tech Talks about acid copper plating. At that time, electroplating systems were primitive and simple. I will focus on the equip- ment changes, because Karl covered most of the plating chemical changes in his columns. Electroplating e plating cell itself has gone through multiple upgrades to accommodate differ- ent chemistries and via constructions. e first innovation I ever saw was in 1971, when Nathan Pritikin (of the Pritikin diet) intro- duced me to a box plater at his PCB shop in Galena, California, and Peter Pellegrino demonstrated his flo-motion plating mani- fold—a fluid manifold with numerous out- lets to distribute the plating electrolyte at such a velocity and volume that it allowed a much higher current density and ion distribu- tion even down into the plated through holes— that could plate one-mil of copper (in the hole) in 15 minutes. Since then, most of the innova- tions have come from plating equipment ven- dors and the rapid growth of multilayer and high-density interconnect PCB. Some areas of focus are discussed here. Next-generation Electroplating Systems Happy's Tech Talk #19 by Happy Holden, I-CONNECT007 Figure 1: The use of an anode box to contain a semi-permeable membrane improves the consumption of additives when employing an insoluble anode for electroplating copper 1 .

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