Structural Estimation and Hazard Evaluation of Potentially Explosive Residual Silanes Generated in Semiconductor Manufacturing Processes

We have proposed a scheme to analyze potentially explosive residual silanes (RS) generated in silicon-based semiconductor manufacturing processes in the Yokkaichi Plant, Kioxia Corporation, properly under an inert gas atmosphere. Thermal analysis and ballistic mortar tests revealed that the incomplete hydrolyzed RS poses the highest risk. The mass spectrum suggests that the possible structures of the major components of the RS are cyclic polychlorosilanes with the number of silicon atoms less than 16. A combination of instrumental analyses and theoretical calculations suggest that the hydrolyzed products of the RS involve Si–OH, Si–O–Si, and Si–Si moieties. Theoretical calculations predicted the substantial exergonic processes of a model compound (HO)­H2Si–SiH2(OH) to form a hydroxylsiloxane and H2.