J. Chem. Eng. Data 2004, 49, 599-606
599
Phase Behavior and Modeling of CO2/Methanol/ Tetramethylammonium Bicarbonate and CO2/Methanol/ Tetramethylammonium Bicarbonate/Water Mixtures at High Pressures Galit Levitin, David Bush, Charles A. Eckert, and Dennis W. Hess* School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0100
High-pressure phase behavior has been measured for CO2/methanol/tetramethylammonium bicarbonate (TMAB) and CO2/methanol/TMAB/water systems at (25 and 70) °C and pressures up to 30 MPa. An increase in methanol concentration results in a decrease in the phase-transition pressure due to the higher miscibility of methanol and salt in CO2. At higher methanol concentrations, single phase mixtures could be achieved at moderate pressures with up to 70 mol % CO2. As expected, the addition of water sharply increases the phase transition pressure. The experimental results for the above systems were modeled using the Peng-Robinson equation of state; model predictions were found to be sensitive to adjustable parameters.
Introduction Cleaning processes represent about 35% of the elementary production steps in advanced integrated circuit (IC) manufacturing, and photoresist stripping accounts for half of these (i.e., typically 50 of the 300 production steps).1 As feature dimensions decrease and new materials are incorporated into device structures, photoresist stripping and etch residue removal face several challenges. Incomplete removal of the residues leads to defects and impurity incorporation into devices, resulting in reduced device yield and reliability.2 Conventional stripping by plasmas3,4 and wet processes5-7 have serious drawbacks. Plasma cleaning can alter structure and properties of low-k dielectrics. Liquid strippers may lead to silicon and metal surface oxidation and have difficulty penetrating narrow trenches of modern devices (
