EUV Mask Absorber Characterization and Selection

摘要

In this paper, we will present our research work in Extreme Ultraviolet Lithography (EUVL) mask absorber characterization and selection. The EUV mask patterning process development depends on the choice of EUVL mask absorber material, which has direct impact on the mask quality such as critical dimension (CD) control, defect control, and registrayion. EUVL mask absorber material selectkon consideration involves many aspects of material properties and processes. These include film absorption at EUV wavelength, film emissivity, film stress, mask CD and defect control, defect inspection contrast, absorber repair selectivity to the buffer layer, etc. The selection of the best candidate is nontrivial since no material is found to be superior in all aspects. In an effort of searching the best absorber materials and processes, we evaluated Al-Cu, Ti, TiN, Ta, TaN,and Cr absorbers. The comparison of material intrinsic properties and process properties allowed us to focus on the most promising absorbers and to further develop the corresponding processes to meet EUVL requirement.