ALD W CMP for HKMG

ALD W CMP characteristic are examined for SiH4 and B2H6 base respectively. ALD W removal rate of B2H6 base is higher than that of SiH4 base. Potentiodynamic polarization scans results indicate that the amorphous structure of the B2H6 base has a higher tendency to be corroded than the polycrystalline structure of the SiH4 base in the W CMP slurry with 2 wt% H2O2. RMS of ALD W after CMP are all less than 1nm for SiH4 and B2H6 base.