EXPERIMENTAL INVESTIGATION OF WIRE SAWING THIN MULTICRYSTALLINE WAFERS

摘要

In this paper we present experimental investigations on wire-sawing thin multicrystalline wafers (down to 140 μm) and a suitable processing processing sequence for high-efficiency solar cells. We assess the material influence on the sawing results as well as the reciprocating cutting scheme. By running the wire back and forth, most geometrical parameters improve while an increased roughness is observed. Additionally, the amount of wire needed in a cut can be considerably reduced. We could experimentally find a relationship for the maximum back reciprocate length in order not to risk wire rupture in the process. For the thin wafer sawing we used a wire guide with stepped thickness so that neighbouring wafers with different thicknesses result. The observed surface quality show an interesting dependence on the wafer thickness. The expected solar cell efficiency increases when the wafer thickness is decreased to reasonable values.