CD bias reduction in CD-SEM linewidth measurements for advanced lithography
CD bias reduction in CD-SEM linewidth measurements for advanced lithography
复制标题
先进光刻的 CD-SEM 线宽测量中的 CD 偏差减少
DOI：
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发表时间：
2008
期刊：
影响因子：
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通讯作者：
P. Vanoppen
中科院分区：
文献类型：
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作者：
Maki Tanaka;J. Meessen;Chie Shishido;Kenji Watanabe;Ingrid Minnaert;P. Vanoppen
实验评估了基于模型库（MBL）匹配技术的线宽测量能力。该技术通过将测量的SEM图像轮廓与模拟线扫描的库进行比较来估计目标图案的尺寸和形状。该仿真模型采用非线性最小二乘法来估计图案的几何参数。为了研究MBL匹配在先进光刻工艺中的应用，用前沿浸没式光刻工具制备聚焦曝光矩阵晶片。评估使用了36个位点，目标结构具有从45到200 nm的各种线宽。通过使用原子力显微镜（AFM）作为参考测量系统来评估测量精度。第一次试验的结果表明，在MBL匹配的参数空间中可以存在两个或更多的解决方案。为了解决这个问题，我们得到了一个粗略的估计尺度参数的SEM成像，根据实验结果，以增加在匹配过程中的约束。结果表明，MBL匹配对侧壁变化的灵敏度得到了提高，测量偏差从22.1 nm减小到16 nm。这些结果表明，通过适当地应用该工具参数，可以提高CD测量能力。
The linewidth measurement capability of the model-based library (MBL) matching technique was evaluated experimentally. This technique estimates the dimensions and shape of a target pattern by comparing a measured SEM image profile to a library of simulated line scans. The simulation model uses a non-linear least squares method to estimate pattern geometry parameters. To examine the application of MBL matching in an advanced lithography process, a focus-exposure matrix wafer was prepared with a leading-edge immersion lithography tool. The evaluation used 36 sites with target structures having various linewidths from 45 to 200 nm. The measurement accuracy was evaluated by using an atomic force microscope (AFM) as a reference measurement system. The results of a first trial indicated that two or more solutions could exist in the parameter space in MBL matching. To solve this problem, we obtained a rough estimation of the scale parameter in SEM imaging, based on experimental results, in order to add a constraint in the matching process. As a result, the sensitivity to sidewall variation in MBL matching was improved, and the measurement bias was reduced from 22.1 to 16 nm. These results indicate the possibility of improving the CD measurement capability by applying this tool parameter appropriately.