Effects of JGB Additives on the Microstructures and Electrical Properties of Electroplated Copper Foil

Abstract

Extremely thin film high quality copper foil is required to ensure high performance in electronics and slimness in secondary batteries. During the electroplating of copper foil, Janus Green B(JGB) and Collagen were introduced as additives to the electrolytes to study their effects. The structural and electrical properties of the electroplated copper foil were evaluated. When each additive was added individually, the potential was increased. Specifically, the potential of the group with 30 ppm added collagen was about 27% higher rather than the non-additive group. When Cl- ions and MPSA(3-mercapto-1-propane sulfonic acid) were added to the electrolytes without collagen and JGB, the surface roughness(Rz) increased by about 136% to 2.24 μm compared to the non-additive group. This was the highest value among all groups. However, a uniform layer with a surface roughness value below 0.3 μm was formed when less than 30 ppm and 10 ppm collagen and JGB were added, respectively, to the electrolyte. The direction of crystal growth with the JGB additives tended to go forward to the (220) direction, and the crystal size was reduced by 10~27% compared to the non-additive group. The addition of Collagen is necessary to reduce the difference in resistivity of the shiny layer and right matte layer. JGB additives were required to reduce the deviation in grain size. The results confirmed that the accelerators, inhibitors and leveler need to be properly added to form a copper plating layer with low surface roughness and to reduce differences in crystal texture of the shiny layer and right matte layer. Copper foil can be safely and uniformly deposited from electrolytes with JGB below 10 ppm and collagen below 30 ppm.