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.