The effects of additives on electrochemical behaviours, microstructure and resistivities evolution of copper during electrodeposition

In the field of microelectronic packaging, copper electrodeposition is one of the core technologies for achieving high-density interconnection and advanced packaging. This process makes full use of the excellent electrical and thermal conductivity of copper, as well as the advantages of low production and maintenance costs of the electroplating process. To obtain high-quality electroplating results, precise coordination between electroplating solution, equipment and process parameters is required. Among them, the electroplating solution plays a key role, which directly affects the appearance, internal structure, composition distribution and long-term reliability of the final copper layer. The synergistic effect between electroplating additives is an important factor in determining the deposition effect. In addition, impurities introduced during the electroplating process will also significantly affect the performance, microstructure and property of the copper coating. Therefore, exploring the appropriate electroplating process has become a research hotspot in recent years.This paper systematically studies the influence mechanism of different electroplating formulas on the electrical, mechanical properties and reliability of copper coatings. The intrinsic correlation is revealed through electrochemical analysis, microstructural characterization by Focused Ion beam microscopy (FIB)and X-ray diffraction (XRD) resistivity test. Based on these research results, it is shown that the leveling agent can significantly affect the crystal orientation of copper deposition and the coating performance, while reducing the impurity content of the coating.