用於次25奈米極紫外光曝光機之新穎反射型衰減式相位移光罩
Other Title
A Novel Structure of Reflective Type Attenuated-Phase-Shifting-Masks for Sub-25 nm Extreme Ultraviolet Exposure Tools
Journal
科儀新知
Journal Issue
148
Start Page
24
End Page
29
ISSN
1019-5440
Date Issued
2005-10
Author(s)
Abstract
相位移光罩(phase-shifting-mask)是目前一種極為重要的解析度增益技術，它將被應用於未來的極紫外光(EUV)微影術中，以製作25 nm以下的圖案。在本文中，根據Fabry-Perot結構並結合一般極紫外光微影光罩材料，展示了一種新穎的反射型衰減式相位移光罩結構。此光罩結構在極紫外光波段不僅可達到180°相位移與高反射率，而且在深紫外光(DUV)波段有高檢視對比度(inspection contrast)。此光罩結構表層有良好的導電性，可以消除光罩製作過程中電子束曝光所造成的電荷累積效應(charging effect)。藉由選擇不同膜堆底層材料與調整膜厚，可以調控吸收區與反射區的反射比從32.6% (TaN/SiO2/Mo) 到4.4% (TaN/SiO2/TaN)。檢視對比度也可以提升至99%，並且有相當大的厚度誤差容許度。
Phase-shifting-masks are vital resolution enhance technique that will be used in extreme ultraviolet (EUV) lithography beyond the 25 nm node. In this paper, we demonstrated a novel structure for a reflective type attenuated phase-shifting-mask, which is based on a Fabry-Perot structure with common materials in EUV masks. The mask structure not only performs 180° phase-shift with high-reflectance at EUV wavelength but also has high inspection-contrast at deep ultraviolet (DUV) wavelength. The top layer of mask structures exhibits good conductivity, which can alleviate the charging effect during electron-beam patterning. The reflectance ratio of the absorber stack could be tuned from 32.6% (TaN/SiO2/Mo) to 4.4% (TaN/SiO2/TaN) by choosing different bottom layers and thickness. The inspection contrast could be raised to 99% with large thickness-control-tolerance.
Type
journal article