Grinding of hard substrates

Abstract

The invention provides improved slurries for the polishing of hard materials such as those having a Mohs hardness of greater than about 6. Exemplary hard surfaces include sapphire, silicon carbide, silicon nitride, and gallium nitride, and diamond. In the compositions and method of the invention, novel compositions comprising a unique combination of additives which surprisingly were found to uniformly disperse diamond particles having a wide range of particle size in a slurry. In the method of the invention, the generally alkaline slurry compositions of the invention are capable of utilizing diamond particle sizes of greater than 40 microns while effecting good removal rates. In such cases, when utilized with a suitable pad, rapid and planar grinding of silicon carbide, silicon nitride, sapphire, gallium nitride, and diamond is possible, with uniform surface damage.

Dependencies are inferred from the claim text.