IMPROVING RESOLUTION IN PHOTOLITHOGRAPHY WITH A PHASE-SHIFTING MASK
IMPROVING RESOLUTION IN PHOTOLITHOGRAPHY WITH A PHASE-SHIFTING MASK
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DOI：
10.1109/t-ed.1982.21037
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发表时间：
1982-01-01
影响因子：
3.1
通讯作者：
SIMPSON, RA
中科院分区：
文献类型：
--
作者：
LEVENSON, MD;VISWANATHAN, NS;SIMPSON, RA
相移掩模由正常透射掩模组成，该掩模涂覆有透明层，该透明层被图案化以确保最近孔径的光学相位相反。来自相邻孔径的波之间的相消干涉抵消了一些衍射效应，并增加了这种图案可以投射的空间分辨率。一个简单的理论预测，对于部分不相干性σ < 0.3的照明，分辨率几乎加倍，并且对于σ < 0.7，分辨率有实质性的改进。与相移掩模图案化与典型的器件结构，通过电子束光刻和曝光使用曼4800 10 X工具获得的初步结果显示，在可用的分辨率增加了40%，一些结构印刷在1000线/mm的分辨率。相移掩模结构可以用来促进接近印刷掩模和晶片之间的较大间隙。理论表明，分辨率的增加伴随着焦深的最小减小。因此，相移掩模可能是VLSI/VHSIC时代提高光刻分辨率最理想的器件。
The phase-shifting mask consists of a normal transmission mask that has been coated with a transparent layer patterned to ensure that the optical phases of nearest apertures are opposite. Destructive interference between waves from adjacent apertures cancels some diffraction effects and increases the spatial resolution with which such patterns can be projected. A simple theory predicts a near doubling of resolution for illumination with partial incoherence σ < 0.3, and substantial improvements in resolution for σ < 0.7. Initial results obtained with a phase-shifting mask patterned with typical device structures by electron-beam lithography and exposed using a Mann 4800 10X tool reveals a 40-percent increase in usuable resolution with some structures printed at a resolution of 1000 lines/mm. Phase-shifting mask structures can be used to facilitate proximity printing with larger gaps between mask and wafer. Theory indicates that the increase in resolution is accompanied by a minimal decrease in depth of focus. Thus the phase-shifting mask may be the most desirable device for enhancing optical lithography resolution in the VLSI/VHSIC era.