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

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 wa ter by inductively coupled plasma mass spectrometry (ICP-MS) were investiga ted. Special efforts have been made to the control of reproducible determin ation of these elements. In order to achieve the highly sensitive ICP-MS de termination, analytes were concentrated by a non-boiling evaporation techni que and measured under normal and cool plasma conditions. The results indic ated that the addition of mannitol and proper control in the evaporation pr ocess 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 establi shed method can be as low as 100 fg g(-1) levels. This method was also appl ied to the determination of impurities in semiconductor-grade chemicals for the 0.25 micron or less logic process. (C) 1998 Elsevier Science B.V. All rights reserved.