844639-65-2Relevant academic research and scientific papers
Oxidative dissolution of copper and zinc metal in carbon dioxide with tert-butyl peracetate and a β-diketone chelating agent
Visintin, Pamela M.,Bessel, Carol A.,White, Peter S.,Schauer, Cynthia K.,DeSimone, Joseph M.
, p. 316 - 324 (2005)
A series of β-diketone ligands, R1COCH2COR 2 [tmhdH (R1 = R2 = C(CH3) 3); tfacH (R1 = CF3; R2 = CH 3); hfacH (R1 = R2 = CF3)], in combination with tert-butyl peracetate (t-BuPA), have been investigated as etchant solutions for dissolution of copper metal into carbon dioxide solvent. Copper removal in CO2 increases in the order tfacH A study of the reactions of the hfacH/t-BuPA etchant solution with metallic copper and zinc was conducted in three solvents: scCO2 (supercrical CO2); hexanes; CD2Cl2. The etchant solution/metallic zinc reaction produced a diamagnetic Zn(II) complex, which allowed NMR identification of the t-BuPA decomposition products as tert-butyl alcohol and acetic acid. Gravimetric analysis of the amount of zinc consumed, together with NMR studies, confirmed the 1:1:2 Zn:t-BuPA:hfacH reaction stoichiometry, showing t-BuPA to be an overall two-electron oxidant for Zn(0). The metal-containing products of the copper and zinc reactions were characterized by elemental analysis, IR spectroscopy, and, as appropriate, NMR spectroscopy and single-crystal X-ray diffraction [trans-M(hfac) 2-(H2O)(CH3CO2H) (1, M = Cu; 2, M = Zn)]. On the basis of the experimental results, a working model of the oxidative dissolution reaction is proposed, which delineates the key chemical variables in the etching reaction. These t-BuPA/hfacH etchant solutions may find application in a CO2-based chemical mechanical planarization (CMP) process.
