Today, wire sawing is perhaps the most popular method used to saw a silicon ingot into wafers. Wire sawing allows for an entire ingot to be sliced into wafers simultaneously, thereby substantially lowering cycle time. Due to a thinner kerf (sawed area), it also produces more wafers from an equal amount of silicon than does ID sawing, for obvious yield enhancement.
During wire sawing the silicon ingot is lowered into a web of ultra-thin wire moving at high rpm. The wire web is actually a single wire being fed from one large spool to another. The cutting action is created by dispensing a silicon carbide slurry over the web while the wire moves in a high-speed, back and forth lateral motion. Silicon carbide slurry used for wire sawing is typically comprised of a silicon carbide abrasive and a liquid media of either specific molecular weight polyethylene glycol or a mineral oil. Intersurface Dynamics has formulated a specialized wire sawing coolant that consistently improves both yield and quality, and is currently developing a specialized polymeric material that stays viscous until exposed to shear, and then returns to its viscous state in the absence of shear.