Determination of ultra-trace impurities in semiconductor-grade water and chemicals by inductively coupled plasma mass spectrometry following a concentration step by boiling with mannitol Original Research Article

Pre-concentration and determination methods for 28 different impurities (Li, Be, Na, Mg, Al, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, Sr, Mo, Ag, Cd, Sn, Sb, Ba, Tl, Pb and Bi) at 100 fg g−1 levels in ultra-pure water by inductively coupled plasma mass spectrometry (ICP-MS) were investigated. Special efforts have been made to the control of reproducible determination of these elements. In order to achieve the highly sensitive ICP-MS determination, analytes were concentrated by a non-boiling evaporation technique and measured under normal and cool plasma conditions. The results indicated that the addition of mannitol and proper control in the evaporation process were effective in preventing loss of several elements such as Ti, Ge, Sn and Sb. The limit of determination for the 28 elements with the established method can be as low as 100 fg g−1 levels. This method was also applied to the determination of impurities in semiconductor-grade chemicals for the 0.25 micron or less logic process.