Investigation of synthesized carbazole derivative Cz-BPDB as a high-performance leveler for copper electroplating

Electroplating additives, especially levelers of copper electroplating, are the most critical components of electroplating solutions in the manufacture of printed circuit boards and integrated circuits. A series of carbazole derivatives have been synthesized and used as levelers for through-hole electroplating. Electrochemical tests, theoretical calculations, and simulations were used to compare the various properties of the carbazole derivatives. Among them, the carbazole derivative Cz-BPDB was preferably subjected to electroplating which was demonstrated by metallographic microscopy, SEM, and XRD. To further investigate the mechanism of leveler Cz-BPDB, the nucleation model theory was used to explain the phenomenon of flat and smooth electroplating surfaces. The electrostatic potential plot and the average local ionization energy plot were employed to analyze the active sites of the Cz-BPDB. Moreover, the galvanostatic measurements were applied to investigate the interaction of the Cz-BPDB with PEG and SPS. Therefore, a more reasonable through-hole electroplating mechanism was proposed in electroplating solution with Cz-BPDB used as leveler. This work introduced an excellent performance leveler and contributed to the continuing development of the copper electroplating mechanism.