I.D., or annular, sawing is a widely used for slicing a silicon ingot into wafers, although wire sawing is replacing it in many larger diameter applications. The I.D. saw blade is a large, round piece of tempered stainless steel with a hole in the middle. The hole accommodates the silicon ingot and is coated with industrial diamonds to form an abrasive surface. The blade spins at a high rpm as it is lowered into the silicon. Once the silicon is cut through, the blade lifts, the ingot indexes and a new wafer is cut.
It is extremely important to cool, lubricate and clean the I.D. blade in order to avoid deflection of a dull cutting surface into the wafer, which results in poor wafer geometry. Wafer geometry correlates directly to the efficacy of an I.D. sawing coolant/lubricant, as poor geometry is a result of poor blade life due to insufficient cooling, lubrication or cleaning. A coolant/lubricant is also necessary to protect machine parts from corrosion at an in-use dilution of ~500 parts water to one part coolant/lubricant (500:1). Intersurface Dynamics’ sawing fluid is proven to provide these process benefits, for the highest quality process results.