Microwave-assisted vapor phase dissolution of photoresist and silicon oxide based slurry samples for the determination of trace impurities by high resolution ICP-MS

Abstract

An effective and contamination free matrix removal method, by closed-vessel microwave assisted volatilization in the presence of vapors of HF and HNO₃, for the determination of trace impurities in photoresist samples and slurry with SiO₂ particles used for chemical mechanical polishing processes in the electronics industry, is reported. The volatilization of the matrix element from the photoresist and slurry is 99.7% and 99.9%, respectively, using vapors generated from a 1 ∶ 9 ratio of HF ∶ HNO₃. The recoveries of Na, Mg, Al, Ca, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ag, Cd, Ba and Pb after volatilization of matrix element are in the range 96–108% and 95–105% for the photoresist and SiO₂ based slurry, respectively. Determinations are carried out using an inductively coupled plasma mass spectrometer with a sector field (ICP-SFMS). The experimental blanks along with the method detection limits computed based on 3σ variation in blank measurements (n = 5) are also reported.