Proposed architecture of a multicolumn electron-beam wafer inspection system for high-volume manufacturing

While optical patterned wafer inspection systems have been successfully used for many years to both improve and control yield during wafer fabrication, their sensitivity is no longer adequate to meet advanced device manufacturing requirements. An alternative is to use wafer inspection systems based on electron-beam technology, which have been commercially available for many years. However, the relatively low throughput of these single-beam systems has kept them from being used to support high-volume manufacturing. One possible way to improve the throughput would be to use multiple columns. However, it has proven difficult in the past to build columns small enough to fit many on a 300 mm wafer and also have the performance of a large single column. Recently, a commercially available scanning electron microscope that utilizes a miniature field-emission column was shown to have adequate resolution to locate defects in a test pattern provided by SEMATECH. The column is all electrostatic and the lenses and def...