Effects of Lithographic Parameters and Geometric Exposure Method for Corner Rounding Correction in Massively-Parallel Electron-Beam Systems for the Mask Pattern Development
Type of DegreeMaster's Thesis
Electrical and Computer Engineering
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The ability of electron-beam (e-beam) lithography to transfer fine features onto a substrate is essential in many applications where high-resolution devices need to be fabricated. However, its low throughput has been the major drawback, especially for transferring large-scale patterns such as optical masks. In order to overcome the drawback, e-beam lithography systems with massively-parallel beams were recently developed and their throughput, improved by several orders of magnitude, has been experimentally demonstrated. In this study, for the optimal use of such parallel-beam systems, the effects of lithographic parameters on the writing quality are analyzed, and the approaches to improve the writing quality of the pattern corner are explored. The metrics of writing quality include the exposure variation and contrast, the total dose required, the dose latitude, the line edge roughness, the corner rounding, and directivity. The proposed correction method analysis including the correction impact from the size of the correction beam, the necessary number of correction beams, correction trade off characteristics from the overlap amount with the regular shot, and design guidelines are discussed. The analysis results obtained through an extensive simulation are provided and discussed in this thesis.