Clean Wafers

© Fraunhofer CSP
Schematic representation of the wet chemical surface extraction.
© Fraunhofer CSP
Lateral distribution of the surface energy of a PV silicon wafer after standard cleaning.

Inorganic and organic impurities on wafer surfaces affect the subsequent process steps as well as the final component function. The quantitative determination of the physico-chemical surface properties enables reliable product and process monitoring. In addition to surface TOC (total organic carbon) analysis for integral quantification of organic impurities and contact angle mapping to determine the homogeneity of surface energy, metallic contaminations in particular can be detected sensitively and quantitatively using SE (surface extraction) - ICP-MS. Our extraction methods are adapted to different surfaces (polished, sawn, etched) and geometries of the wafers. On request, we also develop customer-specific methods.