A new developed method assisting mass transfer of Ni ions in via

Abstract

This paper proposes an idea to assist the mass transfer of Ni ions in via during the electroplating process, which is considered difficult and still unsolved for a via with a high aspect ratio condition. In addition, a new and easier method is proposed to enable observation and analysis of the in situ phenomenon that arises in via plating. The function of selected important operational parameters influencing the electroplating process can be immediately evaluated. Studies show that the added surfactant FS can not only effectively decrease the surface tension of produced H 2 bubbles, but also increase the disturbance within the via; therefore it can enable us to enhance the mass transfer of ions even within the via. This phenomenon confirms that the role of surfactant FS is advantageous in assisting the mass transfer of ions in via, and enables electroplating through the polymeric masks process to be effectively carried out without disruption occurring even at a high height-to-width aspect ratio 30 (AR = 30) condition.

A study on utilizing a chloride bath to electroform MEMS devices with high aspect ratio structures

“…At the beginning of the electroforming process, the major mass transfer mode is diffusion. During the electroforming process, forced convection gradually becomes the primary method of mass transfer [20]. This implies that in order to improve the electroforming performance, we could gradually increase the current density as aspect ratio is decreased.…”