High volume products in manufacturing require fast yield learning, root cause identification, and verification that process or tool problems are fixed. Yield losses of 1% correspond to very large dollar losses. Therefore, it is important to have sophisticated data analysis tools that handle large volumes of data to drive higher yields. This paper will present our methodology for defining yields, assessing wafer yield signatures, and using data analysis tools to determine tools or processes which drive yield loss. A SAS based data analysis tool will be shown which can identify tool or process related problems causing abnormalities in parametrics and impacting yield. Case studies illustrating the usefulness of the tool are shown for a Synchronous Dynamic Random Access Memory (SDRAM) product from our wafer fab. In the final analysis, it is clear that an efficient data analysis approach utilizes resources most effectively and pinpoints yield problems with minimal cycle time.