Characterization of Molecular Interactions between Abrasives and Additives Used in Chemical-Mechanical Planarization (CMP) via Spectroscopic and Computational Methods

ABSTRACT

Understanding the adsorptive interactions occurring at wafer, pad, and abrasive surfaces is a generally accepted as a key requirement for controlling CMP processes. Characterization of adsorptive interactions at a molecular level requires a detailed analysis of the chemical functional groups on both an abrasive and an additive that produce adsorption at the abrasive’s surface. We have recently employed a combination of attenuated total reflectance/Fourier transform infrared absorbance spectrometry (ATR/FT-IR) and computational studies (1) for this analysis. Thin, porous films of either colloidal ceria or silica are deposited on the internal reflection element of an ATR/FT-IR accessory and the infrared absorbance spectra of adsorbed CMP additives on the surfaces of the porous films are recorded. Density functional theory (DFT) calculations are used to assign the IR spectra of the adsorbed additives and to determine the nature of the additive-abrasive adsorption through calculations of energetically favored orientations of an additive with respect to abrasive’s surface functional groups and the water molecules solvating the abrasive’s surface. Representative results obtained using this approach are discussed.

1. Marsh, J.L.; Wayman, A.E.; Smiddy. N.M.; Campbell, D.J.; Parker, J.C.; Bosma, W.B.; Remsen, E.E. Langmuir 2017, 33, 13224-13233.

About the Speaker

Dr. Remsen received his B.S. degree in Chemistry from Manhattan College, a M.S. degree in Chemistry from the Polytechnic Institute of New York, and his Ph.D. in Chemistry from Princeton University. After receiving his doctorate, he joined Monsanto Plastics and Resins Co. as a Senior Chemist in the company’s Springfield, MA research facility. He later transferred to Monsanto’s Corporate Research group in St. Louis, MO and was appointed Monsanto Fellow in 1992. He left Monsanto in 2000 to take a Research Scientist position in the Dept. of Chemistry of Washington University in St. Louis; and returned to industry in 2003 as Senior Scientist and Manager with Cabot Microelectronics Corporation in Aurora, IL. In 2009, he became an Assistant Professor in the Mund-Lagowski Dept. of Chemistry and Biochemistry at Bradley University in Peoria, IL and was promoted to Associate Professor in 2014. His areas of research include single-molecule fluorescence spectroscopic studies of mass transport and adsorption phenomena, LC/MS analysis of carbohydrate biomarkers in fungi, and the characterization of protein-protein interactions in solution. He teaches the analytical chemistry sequence at Bradley which includes Analytical Chemistry, Instrumental Analysis, and Separation Science.