The Study on Electrochemical Mechanical Polishing of Cu Metal Wire in Ammonium Phosphate System and Its Electrochemical Characteristics
Date Issued
2012
Date
2012
Author(s)
Yang, Mu-Huan
Abstract
In this study, the electrochemical characteristics of Cu ECMP were investigated, and we also studied the best working condition during the process of Cu ECMP in ammonium phosphate slurry system. By performing electrochemical measurements such as polarization curves, current-time plot and impedance spectroscopy, the slurry compositions and electrochemical characteristics during ECMP were discussed; besides, surface morphological analysis after ECMP was carried out by atomic force microscopy (AFM). The experimental results showed that the effect of passivation on the Cu surface is better than others when the pH value of electrolyte is 8. As 0.4 voltage was applied during process, the current was more stable. In the case of adding imidazole as the inhibitor, the current would be more stable as the concentration of imidazole was chosen to be 0.3wt%. In the other case of adding benzimidazole as the inhibitor, the concentration of benzimidazole was also chosen to be 0.3wt% for the same reason. By the data of AFM, benzimidazole had better ability to protect Cu surface than imidazole. Finally, we found out that material removal rate would be enhanced by adding abrasive particles, but the effect on planarization of Cu surface would be reduced. So adding abrasive particles is not an effective way to improve the planarization.
The best result of planarization of Cu ECMP in our study is 14.78nm under the working condition: ammonium phosphate electrolyte at pH=8.0, concentration of benzimidazole = 0.3wt%, applied voltage = 0.4V, rotation speed = 300rpm, applied pressure = 0.6psi.
Subjects
ECMP
corrosion inhibitor
imidazole
benzimidazole
Type
thesis
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