The effect of Hydroxy Ethyl Cellulose (HEC) and chloride ions on the surface morphology and mechanical characteristics during copper electrodeposition

The effect of additives on the surface morphology and mechanical characteristics during copper electrodeposition on the polyimide(PI) film was investigated. Two kinds of additives such as hydroxy ethyl cellulose (HEC) and chloride ions were used in this study. Electrodeposition was carried out with the constant current density of 200 mA/cm² for 68 seconds. Electrochemical experiments, in conjunction with SEM, XRD, AFM and four-point probe, were performed to characterize the morphology and mechanical characteristics of copper electrodeposited in the presence of the additives. The minimum surface roughness of copper deposit was obtained when deposited with 10 ppm of chloride ions. The minimum value of surface roughness (rms value) was 97.05 nm. And the optimum amount of additives to improve the electromigration resistance and ductility of the deposit was a combination of 1 ppm HEC and 10 ppm chloride ions.