Offline programming of CD-SEM systems enhances wafer fab productivity

Abstract

The high cost of semiconductor manufacturing equipment and facilities has driven the industry to develop cost of ownership models to evaluate equipment productivity. However, traditional cost of ownership models do not accurately reflect the negative effects of system setup time on overall equipment productivity. The overall equipment effectiveness model is one model which addressed these shortcomings considering system setup time as nonproductive time. We have discovered an opportunity to decrease this nonproductive time with off-line programming capabilities on the new Opal-CD-SEM workstation. Off-line programming allows the process engineer to develop equipment setup recipes concurrent with system operation in production. This new system allows the process engineer to use the fabrication area's existing computer network to access the mask CAD database, stepper job data, and Opal's library of program elements to create a process recipe long before any wafers are actually processed. In practice, this reduces nonproductive equipment setup time and enlarges the overall production utilization of the CD-SEM. In fabs with relatively frequent changes in the production product mix, these improvements have increased productivity significantly.