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http://dx.doi.org/10.6117/kmeps.2022.29.1.049

A Study on The Effect of Current Density on Copper Plating for PCB through Electrochemical Experiments and Calculations  

Kim, Seong-Jin (Department of Materials Science and Engineering, Dong-A University)
Shin, Han-Kyun (Department of Materials Science and Engineering, Dong-A University)
Park, Hyun (Department of Materials Science and Engineering, Dong-A University)
Lee, Hyo-Jong (Department of Materials Science and Engineering, Dong-A University)
Publication Information
Journal of the Microelectronics and Packaging Society / v.29, no.1, 2022 , pp. 49-54 More about this Journal
Abstract
The copper plating process used to fabricate the submicron damascene pattern of Cu wiring for Si wafer was applied to the plating of a PCB pattern of several tens of microns in size using the same organic additives and current density conditions. In this case, the non-uniformity of the plating thickness inside the pattern was observed. In order to quantitatively analyze the cause, a numerical calculation considering the solution flow and electric field was carried out. The calculation confirmed that the depletion of Cu2+ ions in the solution occurred relatively earlier at the bottom corner than the upper part of the pattern due to the plating of the sidewall and the bottom at the corner of the pattern bottom. The diffusion coefficient of Cu2+ ions is 2.65 10-10 m2/s, which means that Cu2+ ions move at 16.3 ㎛ per second on average. In the cases of small damascene patterns, the velocity of Cu2+ ions is high enough to supply sufficient ions to the inside of the patterns, while sufficient time is required to replenish the exhausted copper ions in the case of a PCB pattern having a size of several tens of microns. Therefore, it is found that the thickness uniformity can be improved by reducing the current density to supply sufficient copper ions to the target area.
Keywords
electroplating; copper; organic additive; numerical calculation;
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Times Cited By KSCI : 1  (Citation Analysis)
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