Metal process

New Method for BEOL Overlay and Characterization of Process Margins

Test, measurement and analysis

WHITE PAPERS

Using design-assisted voltage contrast measurement, the method allows online testing and monitoring of process-induced OVL and CD variation.

This article presents a new method, design for inspection (DFI) to characterize the overlap. Using design-assisted voltage contrast measurement, the method enables online testing and monitoring of backend-of-line (BEOL) process-induced OVL and CD variation features with a litho pattern. -etch-lithoetch (LELE). While only some of the features in the multi-color pattern scheme are chosen to be directly aligned, other combinations of metal lines and via colors may exhibit uncontrolled misalignment risking open or short failures. The article shows how full metrological coverage of the multi-color combination between dual-patterned vias and dual-patterned metal lines contributes to improved layup and process margins in 14nm technology. The expanded process margin for Via Opens will result in improved throughput and improved reliability.

Click here to read more.