A novel approach to determine the diamond occupancy of diamond wires for optimized cutting processes for crystalline silicon

The production of wafers from crystalline silicon for solar cells is increasingly realized by diamond wire sawing. A steel core wire is used on which diamonds are fixed in a layer of nickel or resin. The cutting efficiency of the wire is determined by the interplay of the material properties of the crystal that is cut, the cooling fluid and the characteristics of the diamond grit on the wire. Hereby, the density of diamonds with respect to the wire length, the shape of the diamonds and the grain size distribution of the diamonds are important. A new approach is presented to remove diamonds from nickel bonded diamond wires and subsequently analyze their density and grain size distribution. The gravimetrically determined mass of diamonds on the wire shows the same trend as the number of diamonds counted manually on microscope images. Thus, a quality control of diamond wires prior to the wafering process as well as a characterization of the wire wear during the cutting process becomes possible with higher accuracy.