Abstract. Line edge roughness (LER) measurement is one of the metrology challenges for three-dimensional device structures, and LER reference metrology is important for reliable LER measurements. For the purpose of LER reference metrology, we developed an LER measurement technique that can analyze LER distribution along the height of a line pattern, with high resolution and repeatability. A high-resolution atomic force microscopy (AFM) image of a vertical sidewall of a line pattern was obtained using a metrological tilting-AFM, which offers SI-traceable dimensional measurements. The tilting-tip was controlled with an inclined servo axis, and it scans the vertical sidewall along a line pattern with a high sampling density to enable an analysis of the LER height distribution at the sidewall. A horizontal cross-section of the sidewall shows sidewall roughness with sub-nm resolution. Power spectral density (PSD) analysis of the sidewall profile showed that the PSD noise in the high-frequency region was several orders of magnitude lower than the noise of typical scanning electron microscopy methods. AFM measurements were sequentially repeated three times to evaluate the repeatability of the LER measurement; results indicated a high repeatability of 0.07 nm evaluated as a standard deviation of LER at each height.

中文翻译：

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使用计量倾斜原子力显微镜在垂直侧壁上测量参考计量的线边缘粗糙度

摘要。线边缘粗糙度 (LER) 测量是三维器件结构的计量挑战之一，LER 参考计量对于可靠的 LER 测量非常重要。出于 LER 参考计量的目的，我们开发了一种 LER 测量技术，该技术可以分析沿线图案高度的 LER 分布，具有高分辨率和可重复性。使用计量倾斜-AFM 获得线图案垂直侧壁的高分辨率原子力显微镜 (AFM) 图像，它提供 SI 可追溯的尺寸测量。倾斜尖端由倾斜的伺服轴控制，它沿着具有高采样密度的线图案扫描垂直侧壁，以分析侧壁处的 LER 高度分布。侧壁的水平横截面显示具有亚纳米分辨率的侧壁粗糙度。侧壁轮廓的功率谱密度 (PSD) 分析表明，高频区域的 PSD 噪声比典型的扫描电子显微镜方法的噪声低几个数量级。AFM 测量依次重复 3 次，以评估 LER 测量的可重复性；结果表明，0.07 nm 的高重复性被评估为每个高度的 LER 标准偏差。AFM 测量依次重复 3 次，以评估 LER 测量的可重复性；结果表明，0.07 nm 的高重复性被评估为每个高度的 LER 标准偏差。AFM 测量依次重复 3 次，以评估 LER 测量的可重复性；结果表明，0.07 nm 的高重复性被评估为每个高度的 LER 标准偏差。