Abstract. Background: In-line metrology for three-dimensional (3D) profiling high-aspect-ratio (HAR) features is highly important for manufacturing semiconductor devices, particularly for memory devices, such as 3D NAND and DRAM. Aim: Our purpose was to obtain the cross-sectional profiles of the HAR features from top-view critical dimension scanning electron microscopy (CD-SEM) images. Approach: Based on Monte Carlo simulation results, we proposed a method for 3D profiling of HAR features using backscattered electron (BSE) signal intensities. Several kinds of HAR holes with different taper angles and bowing geometries were fabricated. High-voltage CD-SEM was used for experiments to determine the feasibility of our approach. Results: Using the BSE line-profile, we constructed cross sections of the taper holes and estimated sidewall angles (SWAs), which were approximately the same as those observed using field-emission scanning electron microscopy (FE-SEM). The constructed cross sections of the bowing holes and the trends of the geometric variance, which were estimated by the middle CD and its depth, were consistent with the cross sections observed by FE-SEM. Conclusions: The results demonstrate that the variation in the HAR holes, such as SWA and bowing geometry, can be measured and monitored using the BSE images.

中文翻译：

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用于监测高纵横比特征的 3D 轮廓的基于高压 CD-SEM 的应用

摘要。背景：三维 (3D) 剖析高纵横比 (HAR) 特征的在线计量对于制造半导体器件非常重要，特别是对于存储器件，例如 3D NAND 和 DRAM。目的：我们的目的是从顶视图临界尺寸扫描电子显微镜 (CD-SEM) 图像中获得 HAR 特征的横截面轮廓。方法：基于蒙特卡罗模拟结果，我们提出了一种使用背散射电子 (BSE) 信号强度对 HAR 特征进行 3D 剖析的方法。制造了几种具有不同锥角和弓形几何形状的 HAR 孔。高压 CD-SEM 用于实验以确定我们方法的可行性。结果：使用 BSE 线轮廓，我们构建了锥孔的横截面和估计的侧壁角 (SWA)，这与使用场发射扫描电子显微镜 (FE-SEM) 观察到的结果大致相同。弓形孔的构造横截面和几何方差的趋势，由中间CD及其深度估计，与FE-SEM观察到的横截面一致。结论：结果表明，可以使用 BSE 图像测量和监测 HAR 孔的变化，例如 SWA 和弯曲几何形状。