Studies On Co2-Based Slurries And Fluorinated Silica And Alumina Particles For Chemical Mechanical Polishing Of Copper Films

The microelectronics industry has an interest in implementing condensed-CO2-based processes in many segments of the integrated-circuit manufacturing process. Preliminary studies of the behavior of copper surfaces and functionalized nanoparticles were performed in an attempt to offer insight into potential chemical mechanical planarization (CMP) and post-CMP cleaning applications using condensed CO2. Micrometer- and nanometer-sized silica particle surfaces were covalently modified with C8F17CH2CH2Si(CH3)(2)Cl to give C8F17-silica, and alumina particle surfaces were modified with C8F17CH2CH2Si(OEt)(3) and C8F17COOH to yield C8F17-alumina and C8F17COOH-alumina. Atomic force microscopy was used to examine adhesion between these functionalized microparticles and a copper substrate under a nitrogen atmosphere. The adhesion force significantly decreased for the functionalized particles compared to the unmodified particles. In separate studies, copper was exposed to peroxide/beta-diketone solvents containing functionalized nanoparticles to investigate the effect of the nanoparticles on the copper dissolution rate. It was found that copper removal was proportional to the surface oxide and hydroxyl group concentration. (c) 2006 The Electrochemical Society.