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Cu (II) as a Catalyst for Hydrogen Peroxide System Abrasive-Free Polishing on Hard Disk Substrate

With the continuous increase of the hard disk drive capacity, higher requirements are set for hard disk substrate to minimize roughness and defects of the polished surface. Recently, abrasive-free polishing (AFP) has attracted a great deal of attention due to AFP has fewer micro scratches and better cleaning ability than traditional chemical mechanical polishing (CMP). Our present work investigates the effectiveness of Cu (Ⅱ) as a catalyst for hard disk substrate AFP with H2O2 employed as an oxidizer. Polishing slurries used in AFP on hard disk substrate include deionized water, dispersant and oxidizer. The polishing experimental results show that the slurry of H2O2/Cu(Ⅱ) system has higher material removal rate (MRR) than H2O2 system in abrasive-free polishing on hard disk substrate. Further, the catalytic reaction mechanism of Cu (Ⅱ) in AFP of hard disk substrate was investigated. Compared with the H2O2 system, electron spin-resonance spectroscopy (EPR) analysis shows that the H2O2/Cu(Ⅱ) system provides higher concentration of hydroxyl radical. Potentiodynamic polarization measurements shows that corrosion currents (icorr) of disk substrate in the H2O2/Cu(Ⅱ) system is larger than that in the H2O2 system. The results imply that Cu (Ⅱ) as a catalyst for hydrogen peroxide system possesses promising prospects in abrasive-free polishing.