The development of Light Emitting Diode (LED) technology over the past thirty years, has led to an exponential increase in device efficiency and light output, such that LEDs are now becoming the light source of choice for virtually all applications. High brightness LEDs (HB LEDs) are driving market growth of around 20% year on year, for applications such as LCD TV backlighting and general illumination, where LED lamps are replacing standard incandescent and fluorescent lighting. Sapphire (alpha aluminum oxide) is used as the substrate of choice for around 90% of LED chips, with 2" and 4" wafer diameters being the most commonly used. Some leading companies are transitioning to 6" wafer production next year, with 8" wafer processing on the horizon. It is important to produce defect-free sapphire surfaces, in order to efficiently grow the III-V semiconductor stack, responsible for generating the desired wavelengths of light and this is done by CMP. Silica slurries are mostly used as the final polish, but these have very low removal rates, with polishing times of up to a few hours. Silica slurries also exhibit instability at elevated temperatures generated during long polishing and temperature control is critical. As the industry moves to larger diameter wafers, it will become more important to realize increased throughput and therefore, a faster polishing slurry would have a big advantage. Ferro has developed alumina-based slurries for sapphire polishing, which give faster removal rates and greater stability, whilst producing the required surface quality.