Quality assessment of advanced photomasks using the Q-CAP cluster tool

The reduction of wavelength in optical lithography and the use of enhancement techniques like phase shift technology, optical proximity correction (OPC), or off-axis illumination, lead to new specifications for advanced photomasks: a challenge for cost effective mask qualification. `Q-CAP', the Qualification Cluster for Advanced Photomasks, comprising different inspection tools (a photomask defect inspection station, a CD metrology system, a photomask review station and a stepper simulation software tool) was developed to face these new requirements. This paper will show the performance and reliability of quality assessment using the Q-CAP cluster tool for inspection and qualification of photomasks. Special attention is paid to a key issue of mask qualification: the impact of CD deviations, loss of pattern fidelity-- especially for OPC pattern and mask defects on wafer level.