SLM-based DUV laser writers are gaining acceptance for 2nd level PSM and binary mask patterning. These writers can use an e-beam compatible resist enabling tool and process sharing. For binary mask patterning, critical metrics include: critical dimension uniformity (CDU), CD targeting, mask registration, defect performance and inspectability. For PSM applications, pattern fidelity matching to 1st level and PSM overlay are also important. A Sigma7300 is being integrated into 65nm and 45nm production. Binary and PSM mask performance data will be presented. Tool self metrics to characterize SLM health will also be presented. Data conversion, data preparation and production write times will be discussed.
Phase shift mask (PSM) applications are becoming essential for addressing the lithography requirements of the 65 nm technology node and beyond. Many mask writer properties must be under control to expose the second level of advanced PSM: second level alignment system accuracy, resolution, pattern fidelity, critical dimension (CD) uniformity and registration. Optical mask writers have the advantage of process simplicity for this application, as they do not require a discharge layer. This paper discusses how the mask writer properties affect the error budget for printing the second level. A deep ultraviolet (DUV) mask writer with a spatial light modulator (SLM) is used in the experimental part of the paper. Partially coherent imaging optics at the 248 nm wavelength provide improved resolution over previous systems, and pattern fidelity is optimized by a real-time corner enhancement function. Lithographic performance is compared to the requirements for second level exposure of advanced PSM. The results indicate sufficient capability and stability for 2nd level alternating PSM patterning at the 65 nm and 45 nm nodes.