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http://dx.doi.org/10.7464/ksct.2013.19.2.084

Prevention of Running Blots between the Patterns during the Electroless Nickel Electroless Palladium Immersion Gold (ENEPIG) Surface Finish  

Eom, Ki Heon (Department of Chemical Engineering, Pukyong National University)
Seo, Jung-Wook (Manufacturing & Engineering Center, Samsung Electro-Mechanics Co., Ltd.)
Won, Yong Sun (Department of Chemical Engineering, Pukyong National University)
Publication Information
Clean Technology / v.19, no.2, 2013 , pp. 84-89 More about this Journal
Abstract
The running blots between patterns during electroless nickel electroless palladium immersion gold (ENEPIG) surface finish of printed circuit board (PCB) are investigated and a proper solution is presented. Computational chemistry is first employed to understand the process and experiments are then designed to verify the proposed ideas. A $PdCl_2$ activator which has relatively weak chemical bonding to the epoxy resin is introduced to prevent the formation of palladium seeds on the epoxy resin and a couple of operational measures such as increasing HCl concentration and lowering the temperature of Pd activation process are executed to prevent a further hydrolysis of $PdCl_2$ to more stable $Pd(OH)_2$ in aqueous solution. Computational chemistry provides thermodynamic backgrounds for experiments and their results. This combined approach is expected to be very useful in the research of relevant processes.
Keywords
Electroless nickel electroless palladium immersion gold (ENEPIG); Printed circuit board (PCB); Pd activator; Computational chemistry; Density functional theory;
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