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20 The PCB Magazine • May 2015 Michael Carano is with RBP Chemical Technology. To contact the author, click here. and phosphorous dispersion (shown as the dark areas). As one views each of the structures, the differences are remarkable. The anodes from Manufacturer 1 show large and uneven grain boundaries. In addition, the phosphorous is unevenly distributed. This leads to high organic additive consumption, anode sludge and plating roughness. The anodes from Manufacturer 2 and 3 are the ideal quality re- quired for PCB plating for high-aspect ratio holes. Summary While electroplating PCBs with aspect ra- tios greater that 12:1 is probably best accom- plished with periodic pulse reverse plating, di- rect current plating will produce high-quality circuit boards with aspect ratios up to 12:1. This requires that several parameters be opti- mized for throwing power and plating distri- bution. These parameters include plating cell design, high quality copper anodes, solution agitation with use of eductors, anode length and placement and proper selection of organic plating additives and the electrolyte (inorganic chemistry). PCB references 1. D.R.Gabe, Trans IMF 2003, 81, 7. Ward. 2. Yung, E.K. and Romankiw, L., "Fundamen- tal Study of Acid Copper Through-hole Electro- plating Process," Symposium on Electrodeposi- tion Technology, The Electrochemical Society, Pennington, New Jersey, pages 612–635. 3. Chuck Walker and Steve Doyle, Electro- plating: The Importance of Copper Anodes, Finishing World. realtimewith.com CliCk To View VidEo intErViEw iPC Plating Committee Chair George Milad explains the procedure for generating standards, with particular reference to recent revisions of iPC-4552 for eniG and iPC-4556 for enePiC and dis- cusses current developments in ePiG and electroless silver. ENIG & ENEPIG IPC Standards Update by Real Time with... IPC APEX EXPO 2015 OPTIMIzATION OF ACID COPPEr ELECTrODEPOSITION PrOCESSES continues FEaturE

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