Performance requirements of crack detection systems in silicon solar cell production

Abstract

During the production of silicon solar cells crack detection systems can help to sort out damaged wafers and reduce wafer breakage before they enter the production line. In order to be cost effective, the crack detection system needs to minimize false detections as much as possible. False detections in crack detection systems occur when bad wafers are not detected or when good wafers are falsely detected as bad. The first error leads to an increase in cell breakage, the second error raises cell costs because non-damaged wafers are sorted out prior to cell processing. In this work a model has been developed to calculate the maximum allowable error rates of crack detection systems in order to achieve a cost per wafer benefit. Therefore a breakage rate dependent throughput calculation, based on manufacturing data, has been implemented. A sensitivity analysis shows that avoiding a high sorting out rate is crucial to favor the implementation of a crack detection system