The repair of an opaque defect by focused ion beam milling is compromised by non-idealities of the repair process, which include an error in the placement of the repaired edge, over-etching and implantation of gallium into the quartz substrate, and the re-deposition of sputtered material. Through the application of the mask simulation software SOLID-CM (Sigma-C GmbH), the relative influence of these repair artifacts upon the aerial image of a line array after the removal of a line-edge defect on a binary mask was simulated under conditions commensurate with the 100-nm lithography node. From these simulations, we conclude that the repair process would benefit most from an enhancement in the repeatability of edge-placement and from a reduction in the Ga stain. Additional modeling was performed on the tradeoff between the improvement in transmission afforded by the removal of the Ga-stained quartz versus the reduction in light as a consequence of increased scattering by the addition of quartz damage. For the feature size investigated, the aerial image was not improved through the substitution of stained quartz with air. In summary, the simulation of the aerial image after the repair of an opaque defect can greatly aid and guide process development.
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