Observation of the Behavior of Additives in Copper Electroplating Using a Microfluidic Device

The suppression behavior of copper electrodeposition by additives was studied using a microfluidic device. Strong suppression and its cessation due to additive adsorption and deactivation on the plating surface is believed to be crucial for copper bottom-up TSV (Through Silicon Via) filling. In the present study a micro working electrode was prepared on a microchannel wall and electrodeposition was performed with in-situ microscopic observation. During the electroplating, the supply of the additive was interrupted by switching of the plating solution in the microfluidic device, and deactivation of the additive was observed directly. Moderate agreement between the experimental result and numerical simulation was found, and the additive adsorption-deactivation parameters, kp and km, were estimated.