In-situ particle monitoring in a vertical poly furnace

In-situ particle monitoring (ISPM) is a key semiconductor initiative as wafer production facilities strive to reduce operating costs. The benefits of using ISPM include real-time process monitoring, reduced tool qualification costs and improved product cycle time (Pham et al., 1995; Scharnagl, 1996). All of these improvements lead to increased manufacturing productivity and a lower operating cost (Burghard et al., 1992). This paper describes the production implementation of an in-situ particle monitor on an LPCVD vertical furnace. The furnace is a high-risk, critical process to monitor in real time because of the large number of wafers processed in each batch. Correlation between surface scanner counts, ISPM counts, test yield and process trending is discussed, along with sensor reliability and a future plan for statistical control.