The Simulation Studies of Increasing Depth of Focus of Forbidden Pitches by Scattering Bar for 32 nm Linewidth

• Main Authors: Huang Chih-chuan, 黃志全
• Other Authors: Loong Wen-an
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/57121490686374332493

碩士 === 國立交通大學 === 應用化學系所 === 96 === The lithographic simulation software of Prolith v. 9.0 from USA KLA-Tencor was used in this thesis, the positive bias, chromium whole scattering bar (CSB) and attenuated whole scattering bar (ASB) were used to study the relative issues of eliminating the forbidden pitches for 32 nm linewidth. Some important findings of this thesis are reported as following: 1. For 32 nm linewidth, by the modulation of transmittance (T) and phase change of ASB, the width of ASB can be nearly doubled if compared to CSB. At the ASB width 32 nm, transmittance (T)=0.4, and phase change <30 degree, the forbidden pitches can be improved, and also, image of ASB will not be formed. 2. At the smaller pitches, the adding of scattering bars will easily affect the aerial images of main lines, resulted the decreasing of NILS, contrast and depth of focus (DOF), and decreasing of both maximum exposure latitude (ELmax) and maximum DOF (DOFmax). As the pitches increased, before and after the adding of scattering bars, crossing point from 2 curves showed up in the EL vs. DOF plots, rising of position of crossing point followed the increasing of pitches. If the setting of EL is lower than the crossing point, DOF can be increased. So, when crossing points are higher than EL=6%, meet the requirement of this thesis, DOF can be increased, under these conditions, ELmax decreased, and DOFmax increased. As the pitches increased further, the aerial images of main lines will not be affected, however, NILS increased, under these conditions, both ELmax and DOFmax increased. 3. For 32 nm linewidth, the adding of ASB at the smaller pitches, if the main maximum of interference formed by edge effect overlapped, the relative intensity of aerial image from space is relatively high, image of ASB itself will not be easily formed. At the larger pitches, if the main maximum of interference formed by edge effect separated, the relative intensity of aerial image from space is relatively low, image of ASB itself will be easily formed.