Current status of next-generation EUVL mask blank tool development

Mask blanks for extreme ultraviolet lithography (EUVL) are fabricated by depositing Mo/Si multilayer films on super polished substrates. These mask blanks must be nearly defect-free, and therefore particles occurring during the deposition process are a serious concern. Development of the next-generation ultra low defect deposition tool for fabricating EUVL mask blanks is crucial for the commercialization of the EUVL technology. ISMT initiated a project at the ISMT-N (Albany, NY) facility to provide an ion beam sputter deposition tool for multilayer deposition on 6” square format substrates to support the development and production of EUV mask blanks. The project has access to state-of-the-art metrology tools recently installed at the Albany facility and also has process development support from Lawrence Livermore National Laboratory (LLNL) and Veeco. The project goal is to work with suppliers, LLNL, Veeco, to baseline, perform defect and root cause analysis, and improve the current tool with an upgrade path to meet the final specification for EUV mask blanks. We will provide results on the quality of the mask blanks produced during the benchmarking phase of this tool; data will be presented for the EUV reflectivity, reflectance uniformity, centroid wavelength, and uniformity.