Effects of Electrolyte Temperature and pH Value on Behavior and Properties of Electrodeposited Copper

The effects of temperature and pH value of electrolyte on the electrochemical crystallization behavior of copper was investigated through cyclic voltammetry (CV) and chronoamperometry (CA) experiments. The effects of electrolyte temperature and pH value on the phase composition, preferred orientation, microstructure, roughness, and hardness of copper electrodeposited layers were analyzed by XRD, SEM, three-dimensional ultra depth of field microscopy and microhardness tester. The results indicate that the copper electrocrystallization process is a three-dimensional nucleation and growth mode controlled by diffusion. When the electrolyte temperature is 35 degrees C, the electrodeposition efficiency of copper is the highest; when the pH value of the electrolyte is 9, the promotion effect on copper electrodeposition is optimal. The final nucleation mechanism of copper deposition layer at different electrolyte temperatures and pH values is three-dimensional instantaneous nucleation growth. With the increase in electrolyte temperature and the decrease in pH value, the preferred orientation changes from (111) crystal plane to (220) crystal plane. When the electrolyte temperature is 35 degrees C and pH is 9, a flat, dense, rough and hard electrodeposited copper layer can be obtained.