基於直接蒙地卡羅方法之電子束微影圖像模擬及其於電子光學系統優化設計之應用

Abstract

低能電子微影術擁有高解析度，低基底損害，增加光阻敏感度的優勢，被認為實踐22奈米製程的技術之一。為了在高斯電子束柵狀掃描系統下增加製程的產量，電子的曝光量，曝光之距離和曝光點大小等參數必須謹慎選取，以達到產量的最佳化。為此我們以一個蒙地卡羅的模擬方法去模擬出光阻的曝光形狀，根據邊緣粗糙度對ITRS上的標準值的比較而把以上所述的參數的邊界找出。同時把曝光形狀作為電子光學系統的判定條件，對電子光學系統的參數作出進一步的最佳化。

Low-energy electron beam lithography (LEEBL) is a promising patterning solution for the 22-nm half-pitch node and beyond due to its high resolution, low substrate damage, and increased resist sensitivities. In order to achieve throughout required for high-volume manufacturing, writing parameters such as probe size, pixel size, electron dosage, proximity correction scheme, and number of beams need to be carefully selected in a Gaussian-beam–raster-scan system. In high-throughput LEEBL, line edge roughness (LER) caused by shot noise becomes a critical issue for both device patterning and device performance variability. To characterize these effects, stochastic MOSFET gate patterning with LEEBL is constructed by overlapping energy distributions from an in-house electron scattering Monte Carlo simulation program with various writing parameters. Parameter optimization can help provide initial guidelines and specifications for design and operation of multiple electron beam direct-write systems.