The need for LWR metrology standardization: the imec roughness protocol
The need for LWR metrology standardization: the imec roughness protocol
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LWR 计量标准化的必要性：imec 粗糙度协议
DOI：
10.1117/12.2294617
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发表时间：
2018
期刊：
影响因子：
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通讯作者：
S. Koshihara
中科院分区：
文献类型：
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作者：
G. Lorusso;T. Sutani;V. Rutigliani;F. van Roey;A. Moussa;A. Charley;C. Mack;P. Naulleau;V. Constantoudis;M. Ikota;T. Ishimoto;S. Koshihara
随着半导体技术不断向前发展，不受未来诸多挑战的影响，一个特定的可交付成果引起了该领域许多专家的关注：线宽粗糙度（LWR）规格预计在短期内将低于2nm，并在短短几年内降至1 nm以下。这是一个艰巨的挑战，整个行业的工程师都在努力使用他们所掌握的一切手段来实现这些目标。然而，尽管目前的努力肯定令人钦佩，但我们认为这些努力还不够。事实是，只有当有一个商定的方法来验证是否符合标准时，规范才有意义。这种标准化在任何科学技术领域都是至关重要的，我们今天需要问自己的问题是我们是否有标准化的轻水堆计量。换句话说，如果只提供一个参考样本，那么每个测量它的人都能得到合理的可比结果吗？我们开始意识到，事实并非如此，整个行业的结果分布相当大。在我们看来，这使得机构之间的LWR数据的比较，或规范，非常困难。在本文中，我们报告了测量的LWR数据在半导体行业的传播。我们调查的图像采集，测量算法，和频率分析参数LWR计量的影响。我们对国际半导体技术路线图（ITRS）的一些计量准则（如测量盒长度大于2μm和需要校正SEM噪声）进行了严格的审查。我们比较SEM粗糙度的结果，AFM测量。最后，我们提出了一个标准化的LWR测量协议-imec粗糙度协议（iRP）-旨在确保每次LWR测量进行比较（从各种来源或规格），比较是明智的和健全的。我们坚信，该行业正处于这样一个时刻，即必须确保在谈论LWR等关键参数时，每个人都说同一种语言，而目前并非如此。
As semiconductor technology keeps moving forward, undeterred by the many challenges ahead, one specific deliverable is capturing the attention of many experts in the field: Line Width Roughness (LWR) specifications are expected to be less than 2nm in the near term, and to drop below 1nm in just a few years. This is a daunting challenge and engineers throughout the industry are trying to meet these targets using every means at their disposal. However, although current efforts are surely admirable, we believe they are not enough. The fact is that a specification has a meaning only if there is an agreed methodology to verify if the criterion is met or not. Such a standardization is critical in any field of science and technology and the question that we need to ask ourselves today is whether we have a standardized LWR metrology or not. In other words, if a single reference sample were provided, would everyone measuring it get reasonably comparable results? We came to realize that this is not the case and that the observed spread in the results throughout the industry is quite large. In our opinion, this makes the comparison of LWR data among institutions, or to a specification, very difficult. In this paper, we report the spread of measured LWR data across the semiconductor industry. We investigate the impact of image acquisition, measurement algorithm, and frequency analysis parameters on LWR metrology. We review critically some of the International Technology Roadmap for Semiconductors (ITRS) metrology guidelines (such as measurement box length larger than 2μm and the need to correct for SEM noise). We compare the SEM roughness results to AFM measurements. Finally, we propose a standardized LWR measurement protocol - the imec Roughness Protocol (iRP) - intended to ensure that every time LWR measurements are compared (from various sources or to specifications), the comparison is sensible and sound. We deeply believe that the industry is at a point where it is imperative to guarantee that when talking about a critical parameter such like LWR, everyone speaks the same language, which is not currently the case.