Data analysis of industrial czochralski process: Investigation of ingots with structure loss

As the demand for high-quality silicon ingots rises, enhancing efficiency and yield in silicon wafer production remains essential. The Czochralski method continues to face challenges such as structure loss (SL), which significantly affects production yield. Tackling these issues is crucial to meet the growing industrial need for reliable and efficient silicon ingot production. This study employs data analysis to investigate industrial 7-inch Czochralski silicon ingots doped with phosphorus, sourced from two industry partners, to assess how specific process parameters influence SL. Our analysis covers the effects of pressure and gas flow, with findings indicating that SL incidents are associated with higher pressure buildup at the end of the growth process, while gas flow variations do not significantly impact SL. We also explored the influence of crucible size, noting a slight increase in SL risk with larger crucibles, and assessed the impact of feedstock types and combinations on SL occurrences. Our findings indicate that structure loss is more likely to occur within the initial 600 mm of crystal growth, particularly in the first ingot grown in the quartz crucible. A substantial portion of structure loss incidents were found to be associated with low thermal gradients at the point of failure, and a significant reduction in thermal gradient correlates with higher SL rates. Extended stabilization times were observed to decrease the likelihood of structure loss, highlighting the importance of process stabilization. Additionally, approximately 25 % of structure loss events were linked to foreign particle impacts at the solid-liquid interface. • Increased pressure buildup at the end of growth correlates with higher structure loss (SL). • Larger crucibles slightly raise the risk of structure loss during Czochralski growth. • Structure loss is more frequent in the initial 600 mm of crystal growth. • Low thermal gradients at the growth point are associated with higher SL rates.