Ruben G. Carbonell

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-CO 2 -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 CO 2 . Micrometer- and nanometer-sized silica particle surfaces were covalently modified with C 8 F 17 CH 2 CH 2 Si(CH 3 ) 2 Cl to give C 8 F 17 -silica, and alumina particle surfaces were modified with C 8 F 17 CH 2 CH 2 Si(OEt) 3 and C 8 F 17 COOH to yield C 8 F 17 -alumina and C 8 F 17 COOH-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/ P-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.