Effect of Nitrogen-containing Groups on the Reduction of Copper Ions: In situ Raman and AIMD

Abstract

In situ Raman spectroscopy and ab initio molecular dynamics (AIMD) were utilized to observe and analyze the micro-scale variations of levelers on the cathode surface. The cathodic polarization and charge transfer resistance of the three electroplating systems were examined using electrochemical methods. The throwing power of the printed circuit board coating and the nucleation changes at various times were investigated using an OLYMPUS confocal laser microscope and a scanning electron microscope. Based on the first-principles and AIMD calculations, the energy gaps, adsorption energies, and dynamic changes over 20 ps for the three levelers were determined, and the molecular mechanisms of action on the copper surface were analyzed to demonstrate alterations in the coating thickness. Experimental and theoretical results indicate that 2-thiazole-2-thiol possesses the strongest inhibitory energy, significantly repelling copper ions from migrating to the far end. On the surface, 4,6-dimethyl-2-pyrimidinethiol decomposes to form nitrogenous and sulfurous groups, which inhibit and adsorb copper ions. The adsorption states of the three levelers were thoroughly validated using Raman spectroscopy, corroborating the AIMD simulation results.