Analysis of the topography and the sub-surface damage of Cz- and mc-silicon wafers sawn with diamond wire

Abstract

The goal of this work was to investigate the influence of different sawing coolants concerning topography parameters and fracture strength of diamond wire sawn Cz- and mc-Si wafers. Therefore, silicon bricks were sawn using glycol- and water-based coolants. Fracture strength was determined by four bending bar fracture test setup. Additionally, crack depth analyses on beveled samples depending on the crystal orientation of the investigated grains have been done by means of XRD measurements. We found a strong indication of a crystal orientation dependency of the crack depth. Furthermore, we have made single scratch tests with a novel scratch test technique, which offers the possibility to use test parameters comparable to real sawing conditions. The scratch tests have been done on Cz-Si. We investigated the cracks using OCM and SEM images as well as Raman spectroscopy of cross section preparations through the single scratches.