Journal of the Korean institute of surface engineering (한국표면공학회지)

The Korean Institute of Surface Engineering (한국표면공학회)
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Effects of PEG addition as an additive for electroplating of Cu at high current density

고전류밀도 전해도금 공정에서 PEG 첨가 효과

  • Byeoung-Jae Kang (Department of Metallurgical Engineering, Jeonbuk National University) ;
  • Jun-Seo Yoon (Department of Metallurgical Engineering, Jeonbuk National University) ;
  • Jong-Jae Park (Department of Metallurgical Engineering, Jeonbuk National University) ;
  • Tae-Gyu Woo (Graduate School of Flexible and Printable Electronics and LANL-CBNU Engineering Institute Korea, Jeonbuk National University) ;
  • Il-Song Park (Department of Metallurgical Engineering, Jeonbuk National University)
  • 강병재 (전북대학교 금속공학과) ;
  • 윤준서 (전북대학교 금속공학과) ;
  • 박종재 (전북대학교 금속공학과) ;
  • 우태규 (전북대학교 유연인쇄전자전문대학원 및 로스알라모스연구소-전북대학교 한국공학연구소) ;
  • 박일송 (전북대학교 금속공학과)
  • Received : 2024.07.04
  • Accepted : 2024.07.23
  • Published : 2024.08.31
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Abstract

In this study, copper foil was electroplated under high current density conditions. We used Polyethylene Glycol (PEG), known for its thermal stability and low decomposition rate, as an inhibitor to form a stable and smooth copper layer on the titanium cathode. The electrolyte was composed of 50 g/L CuSO4 and 100 g/L H2SO4, MPSA as an accelerator, JGB as a leveler, and PEG as a suppressor, and HCl was added as chloride ions for improving plating efficiency. The copper foil electroplated in the electrolyte added PEG which induced to inhibit the growth of rough crystals. As a result, the surface roughness value was reduced, and a uniform surface was formed over a large area. Moreover, the addition of PEG led to priority growth to the (111) plane and the formation of polygonal crystals through horizontal and vertical growth of crystals onto the cathode. In addition, the grains became fine when more than 30 ppm of PEG was added. As the microcrystalline structure changed, mechanical and electrical properties were altered. With the addition of PEG, the tensile strength increased due to grain refinement, and the elongation was improved due to the uniform surface. However, as the amount of PEG added increased, the corrosion rate and resistivity increased due to grain refinement. Finally, it was possible to manufacture a copper foil with excellent electrical and mechanical properties and the best surface properties when electroplating was carried out under the condition of additives with Cl-20 ppm, MPSA 10 ppm, JGB 5 ppm, and PEG 10 ppm.

Keywords

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