Together with slurries, pads play an important role in the mechanical and chemical processes used to polish and planarize wafers.  Pads are typically characterized based on their bulk physical, mechanical, and microstructural properties as they correlate to polishing performance.  Surface interactions at the pad-slurry interface can be characterized using contact angle and zeta potentiometry to measure surface energy and electrokinetic properties.  The molecular structure of the polyurethane material is a critical factor that defines many of the aforementioned pad characteristics.  For example, the stiffness of a chain and the degree of cross-linking are important factors in targeting hardness, elasticity, temperature resistance, and chemical affinity.  The ability to measure and understand the polymer structure and bond composition of a pad is a critical tool to rationalize performance and to design new materials that address future polishing needs.  In this paper, a fundamental molecular study on the polymer structure and network formation will be described.  The work was performed using Fourier Transform infrared spectroscopy coupled with a thermally controlled attenuated total reflection (ATR) accessory.  After an overview of the main polyurethane infrared absorption bands, the investigation will provide important molecular formation insights related to the polymerization reaction (gelation),  curing, and final structure of the polymer.