Bisphenol A Polyoxyethylene Ether Sodium Sulfate as a New Leveler for Electrodeposition of Copper

The electrochemical behavior of three types of bisphenol A polyoxyethylene ether sodium sulfate (BPA) is investigated through cyclic voltammetry striping tests. The results indicate that BPA-25 exhibited the most significant inhibition of Cu deposition. The nanotwinned Cu (nt-Cu) films are prepared by direct current electrodeposition in an acidic Cu sulfate bath containing a combination of conventional bath additives. Transmission electron microscopy (TEM) and cross-sectional scanning electron microscopy (SEM) results revealed that nt-Cu consisted of microcolumnar grains with high-density nanoscale coherent twin boundaries oriented parallel to the growth surface. The interaction between BPA-25 and the poly2-sulfur-2-propane sodium sulfonate (SPS) was further analyzed through galvanostatic measurements (GMs) and electron backscatter diffraction (EBSD). The results demonstrate that BPA-25 and SPS underwent competitive adsorption on the cathode surface, leading to the formation of nt-Cu. This growth mechanism provides a new perspective for the preparation of nt-Cu by using direct current electrodeposition.