pA method of forming a substrate is performed by grinding a substrate using abrasives so that both major surfaces of the substrate achieve desired flatness, smoothness , or both. In an embodiment ,a coarser abrasive is used to grind one major surface , while a finer abrasive is simultaneously used to grind the other major surface. A single grinding step can used to produce a substrate having opposing surfaces of different surface roughnesses. This may help to eliminate a typical second downstream fine polishing step used in the prior art. Embodiments can be used with a wide variety of substrates, including sapphire, silicon carbide and gallium nitride single crystal structures grown by various techniques./p
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