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.