Silicon Slicing with Diamond Wire for Commercial Production of PV Wafers

Today’s industrial standard technique for wafering substrates for photovoltaic processing typically involves the use of steel wire and a slurry mixture. This process is reaching its limitation in achieving further cost reductions. New silicon wafering technology using diamond coated wires has been developed for commercial production and is presented in this paper. The new process improves the sawing efficiency substantially and therefore increases productivity by a factor of two or more in terms of table feed speed. The wire lifetime is increased substantially due to this fixed abrasive sawing process and using appropriate sawing parameters, therefore reducing the overall wafering cost potentially significantly. We demonstrate the advantages of using diamond wire sawing in a manufacturing environment resulting in increased productivity while at the same time producing wafers with excellent quality, similar or better than slurry cut reference wafers, e.g. showing very low surface metal contamination and total thickness variation of less than 10 μm. This was demonstrated both for cutting in a reciprocating mode and in a single direction with long lengths of diamond wire.