Industrial realization of dry plasma etching for PSG removal and rear side emitter etching

Inline production sequences are gaining more and more importance considering improved material flow and decreasing wafer material thickness. With the application of dry phosphorus silicate glass (PSG) etching combined with a subsequent SiNx deposition a further simplification of the process flow can be reached. Within this work, a new prototype etching and deposition system from Roth&Rau (called MAiA) is presented implementing a dry PSG removal, a single side emitter etch for the rear side as well as a SiNx deposition without leaving the vacuum line. Each process step itself has been tested and optimized and complete multicrystalline silicon solar cells have been produced implementing the new process sequence.