An alternate of MPS and SPS collocated with dimensionally stable anode (DSA) for Cu fill of microvia and TSV

To exhibit superfilling phenomenon in microvia and through silicon via (TSV), small amounts of organic and inorganic compounds are employed as additives in commercial electroplating baths. In addition, the desired deposition results, such as morphologies and textures, are thereupon obtained " A typical formula used in laboratory that is able to achieve superfilling consists of CuSO₄, small amounts of Cl", a suppressor, and an accelerator. The common accelerators are bis(3-sulfopropyl) disulfide (SPS) and mercaptopropylsulfonic acid (MPS). Recently, their electrochemical properties and behaviors have been widely investigated and discussed. " Herein, we developed a novel accelerator that can replace MPS and SPS. To the best knowledge, there is no report on the study of this additive. In addition to that mentioned above, we know that the common material of anode is phosphorus-containing copper. But the phosphorus-containing copper is consumable and reacts with the plating additives to produce undesirable by-products. Here we chose dimensionally stable anode (DSA) to take the place of the traditional phosphorus-containing copper anode because it has many beneficial properties such as high corrosion resistance, physical, chemical stability and long service life under high positive potentials. So it is anticipated that DSA will be the future trend as the choice of anode. We also found that the electrochemical behaviors of additives in the system with DSA differ from that with phosphorus-containing copper. The possible reason may be related to the anodic potential and composition of anode. Finally, we successfully integrated a novel accelerator (TBPS) with the DSA and searched out the optimal concentration rang and plating condition to meet our desired results in the Cu fill of microvia and TSV.