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Improving Manufacturing Process Efficiency Through Automated Analysis by Laurie Union, Product Marketing Manager
Cycle time and throughput are major cost issues in semiconductor manufacturing today. Yield and process engineers spend substantial time reacting to defective lots on a one-to-one basis, thereby reducing the total impact they can have on the yield-improvement process. Installation of KLA-Tencor’s new automated analysis system together with the company’s on-line automatic defect classification (ADC) system at a customer site, has been shown to greatly improve cycle time and reduce manufacturing costs in semiconductor processing. Two of KLA-Tencor’s yield management solutions were used for the purpose of this study — Klarity™ and IMPACT/Online™ ADC. Klarity, KLA-Tencor’s automated analysis system, embeds expert decisionmaking processes in the company’s defect analysis software resulting in accelerated resolution of problems impacting fab yields. IMPACT/Online ADC, the company’s on-line automatic defect classification system, quickly and accurately classifies defects in real time according to userdefined categories, surpassing the capabilities of manual classification techniques. Engineers at a major semiconductor manufacturing site in the United States were assigned the task of implementing a more automated system to transfer some of the 22
Summer 1998
Yield Management Solutions
routine analyses to IMPACT/Online ADC and Klarity. IMPACT/Online ADC was implemented to eliminate the need for time-consuming manual classification. Klarity was implemented to automate complex manual analyses and, thereby, reduce lot disposition overhead. Image classifications were taught to the IMPACT/ Online ADC system. This was completed prior to the implementation of Klarity to allow the system to make intelligent classifications and thus move some of the routine lot dispositioning tasks from the hands of the engineers and technicians to the fab operators. Klarity was installed and connected to all defect measurement systems including the IMPACT/Online ADC system. Klarity, with its unique Decision Flow Analysis™ (DFA) capability (figure 1), allowed the engineering team at this site to build recipes that encapsulated the kinds of decisions and process instructions they would normally perform on a lot-by-lot basis. Klarity recipes were tested on two of their high-volume semiconductor products with more than 15 zones (process sectors). One of the recipes incorporated statistical process control where lots were tracked at each process zone with specific limits and then dispositioned automatically (figure 2). This was done as the data was being processed across the network and was loaded into the database in real time.