Advanced methods for analysis of wafer-to-wafer yield variation

A fab-wide, wafer position tracking (WPT) system, along with advanced methods for data analysis, has been developed and implemented at AMD´s Submicron Development Center (SDC). This system partitions the manufacturing flow into segments to efficiently monitor the entire process without adversely affecting cycle time or defectivity. A fully automated system of data analysis detects systematic relationships between wafer processing order and yield and/or parametric data. The system can detect linear, alternating, end-wafer, and other non-random trends. In addition, a spatial analysis technique has been incorporated for added sensitivity to small, localized phenomena. The modular nature of the WPT system allows it to be used with other wafer-level, data-gathering tools such as an in-situ particle monitor (ISPM). The analysis of wafer-to-wafer yield variation using this system has led to tightening of the wafer-level yield distribution and resulted in increased overall yield