Nanomachining processes for 45, 32 nm node mask repair and beyond

The transition to sub 45 nm technology nodes presents a significant technical challenge for mask repair due to a number of previously lesser known physical phenomena. Nanomachining technology, which has a history of equally successful repair of all photomask types-including Cr binary masks, has not been immune to these challenges. This has led to the development of a number of distinctly new processes to meet these technical requirements. In one of the two new processes reviewed in this work, the bulk of the defect is removed by applying compressive instead of tangential stresses to the NanoBitTM during repair. This allows for 45 nm and smaller repairs, with sidewall angles and aspect ratios greater than 70° and 2:1 respectively, in open mask structures. For repair in closed-or missing defect-structures, a process was developed to minimize tip deflection away from the designated repair box boundaries for accurate two dimensional shape reconstructions of deep and complex patterns. The successful application of this technique is shown for actinic phase-correct missing and partial CPL, EAPSM, and Cr-absorber square contacts at these nodes. Additionally, the potential of these new processes to enable higher aspect advanced NanoBitTM designs for robust mask repair, and the new processes developed to effectively clean nanomachining debris from these advanced mask structures are discussed to provide a complete review of these solutions and their supporting technologies.