Effect of pH on Hard Disk Substrate Polishing in Glycine-Hydrogen Peroxide System Abrasive-Free Slurry

The effect of pH on the material removal rate (MRR) and surface roughness (Ra) of hard disk substrate in glycine–hydrogen peroxide system abrasive-free slurry was investigated. The results show that, the MRR of hard disk substrate increases when both glycine and H2O2 are used in acidic slurries (pH=3.0) and decreases drastically in alkaline slurries (pH=10.0). The Ra of hard disk substrates is small in acidic slurries and increases drastically in alkaline slurries. Further, the effects of glycine, H2O2, and solution pH on hard disk removal were investigated by auger electron spectroscopy (AES), electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization measurements. We also develop a reaction scheme describing the surface chemistry of the hard disk in this system.