Critical issues for developing a high-throughput SCALPEL system for sub-0.18 micron lithography generations

The potential for SCALPEL to provide economically viable production lithography capabilities for post-optical generations depends largely on achieving adequate wafer throughput. We have analyzed throughput-limiting performance attributes of the SCALPEL approach in order to identify critical design issues and develop a process for evaluating its unique parameter space. An important feature of the SCALPEL approach is that small image sub-fields are assembled to form complete device patterns. Further, electron-electron interactions result in a throughput-dependent image blur, which is a governing parameter for many inter-related performance areas of SCALPEL. Error budgets for key issues affecting critical dimension (CD) have been developed to analyze this unique design space, using models of the image-forming process including stitching on sub-field seams. These budgets assist in identifying the most critical design issues and demonstrating their inter-relationships and tradeoffs.