Exploring Advanced Mask Repair Options

摘要

The extension of 193 nm lithography to the 65 and 45nm nodes transfers the development challenges from those associated with a new wavelength to those required to push an existing technology further. With respect to mask repair, new challenges are introduced as the mask features shrink and OPC becomes increasingly aggressive. These same factors increase mask costs to provide strong motivation for enhancing existing repair capabilities. The business case for investing in repair has only become stronger for leading edge 193 nm masks. This paper evaluates several repair techniques on a range of clear and opaque defects in Cr, MoSi and quartz features. A systematic approach is used to evaluate options for understanding the quality of a repair. Though conventional reconstruction techniques are used, we also explore non-intuitive repairs. These non-standard repairs attempt to reconstruct the printed image without duplicating the designed physical structure. An understanding of each method's process latitude is gained. AIMS analysis, lithographic simulations, and wafer print results are used to refine the understanding of repair specifications.