A Condition Change Detection Method for Solar Conversion Efficiency in Solar Cell Manufacturing Processes

A solar cell manufacturing process typically has multiple, serial fabrication stages. In general, there are limited quality inspection and control points along the multiple fabrication stages, resulting in inconsistent product quality at the final stage. The existing studies on solar cell manufacturing focus on offline quality monitoring after completion of all manufacturing stages. Thus, an effective in-process method of detecting changes in key stages in terms of product quality is necessary to mitigate the effect of the quality fluctuation. This paper proposes an in-process method of detecting the process changes in terms of product quality by studying multichannel sensing signals collected in the epitaxy stage. This stage is an important stage of material layer formation and considerably influences the solar conversion efficiency of the final product. Interpretable geometric features are obtained by considering the process knowledge for each channel of sensing data. A decision-level data fusion method is further proposed to integrate the changes detected from each sensing signal. The proposed method is demonstrated via a real case from solar cell manufacturing processes.