Yield Management Enhanced Advanced Process Control System (YMeAPC)—Part I: Description and Case Study of Feedback for Optimized Multiprocess Control

Abstract

In today's competitive semiconductor manufacturing environment, improving fab productivity and reducing cost requires that all systems work collaboratively towards production, quality and cost targets. Equipment engineering systems (EES), including advanced process control have risen to the top as key enablers for maximizing fab productivity, however these systems have been hindered as they focus on equipment and process, rather than fab-wide, metrics. Extending EES into the yield management space allows for leveraging yield prediction information as feedback into closing the loop around the fab to better achieve productivity goals. With this added capability of yield prediction, EES can: 1) predict yield excursions as well as excursion sources (leveraging virtual metrology technology), thereby avoiding costly post mortem yield recovery activities; 2) improve EES capabilities such as maintenance management and scheduling/dispatch; and 3) utilize yield prediction information as feedback to all levels of control in the fab, from individual processes up through factory-level controllers so that processes can be continuously tuned to meet yield and device performance targets without resorting to design changes to slower products. Case studies of application of this feedback information illustrate that benefits can be achieved from straight-forward applications, however these benefits can be expanded (especially) as more complex scheduling and control solutions are implemented. Realizing this type of yield-enhanced EES solution (YMeAPC) in a cost-effective manner requires fab-wide adherence to standards and best practices for component integration, event-based control system operation, and user interface management.