Semiconductor device fabrication is a complex, multistep process involving both photolithographic and chemical techniques. Step one involves slicing an ingot of semiconductor material, typically monocrystalline silicon, into thin wafers. Each wafer then undergoes a microfabrication process and serves as the substrate for hundreds of integrated circuits (IC) that get cut into individual chips.
To obtain the highest quality chips, the silicon ingot must be free of all defects. This is critical, because the wafer undergoes stress during slicing, fabrication and cutting. Cracks at any stage of production make the wafer unusable.