As the next major inflection in lithography, EUV is making steady progress towards production implementation. Similar to past major technology inflections, it is critical to understand the sources of process variation associated with EUV lithography to enable ramp at optimal yield. With EUV, the sources of process variation could be based on the new lithography technology, but also could be related to infrastructure elements associated with EUV lithography – e.g., new materials and mask types. Thus, the industry has to focus on ensuring the readiness of the EUV infrastructure and the success of EUV’s process ramp.
Further with the advanced process nodes that EUV enables, process windows are getting small. The challenge has grown beyond identifying the process window, to needing to monitor metrology and defect parameters at multiple points, so that process shifts are identified and corrected as quickly as possible. To monitor a dynamic process, inspection and metrology tools need to have sensitivity to a wide variety of defect types plus robustness to process variation, so that they can capture all defect types or measure all parameters even as the process center moves.