NEW DEVELOPMENTS IN PLASMA ENHANCED CHEMICAL ETCHING AT ATMOSPHERIC PRESSURE FOR CRYSTALLINE SILICON WAFER PROCESSING

摘要

In standard production technology of crystalline silicon solar cells most of the etching steps are carriedout by wet chemical processing. In an advanced in-line process sequence, there is a potential interest in dry etchingas alternative to the current technology, especially when combined with similar process technologies, for exampleatmospheric pressure deposition techniques.Based on a linear extended DC arc with a working with of 150 mm for plasma activation, an innovative atmosphericpressure plasma etching technology was studied and optimized. In this contribution, an up-graded reactor design ispresented with allows higher etch rates (higher wafer throughput) than previously reported. In-situ gas phase FourierTransformed Infrared Spectroscopy (FTIR) has been carried out in order to estimate the utilization of the etch gas inthe new reactor configuration. Rear side etching and edge isolation of 125×125 mm~2 mono-crystalline silicon wafershave been carried out with NF_3 as etch gas on wafers which were processed to solar cells under industrial conditions.