Analysis of Pre- and Post-Conditioned Polyurethane CMP Pad Surfaces as a Function of Conditioning Temperature

• Published in: ECS transactions Vol. 3; no. 41; pp. 31 - 44
• Main Authors: Prasad, Abaneshwar, Xiang, Hongqi, Wang, Jianhua, Remsen, Edward E.
• Format: Journal Article
• Language: English
• Published: 10.12.2007
• ISSN: 1938-5862; 1938-6737
• DOI: 10.1149/1.2819479

The investigation of water diffusion in polyurethane CMP pads via hydrogen-deuterium (H-D) exchange, measured by attenuated total reflectance/FT-IR (ATR/FT-IR), is reported. Significant differences in the kinetics of H-D exchange for a thermoplastic polyurethane (TPU) pad and a conventional cross- linked polyurethane (PU) pad were found. These differences were attributed to the intrinsic chemical and physical differences between the polymeric materials constituting the pads that were characterized by liquid chromatography/mass spectrometry (LCMS) and 1H NMR spectroscopy. Extraction kinetics for low molecular weight compounds in the pads are reported. H-D exchange kinetics for both TPU and PU pads show a strong dependence on temperature and were unique to the specific pad type. Pad conditioning also influenced the kinetics. These findings suggest a re-organization of chain segments at or near the surface during pad conditioning. Additiona l studies are proposed to characterize the nature of the molecular changes modulating water diffusion in the pads.