Real-time profile shape reconstruction using dynamic scatterometry
Real-time profile shape reconstruction using dynamic scatterometry
复制标题
使用动态散射测量进行实时轮廓形状重建
DOI：
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发表时间：
2007
期刊：
影响因子：
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通讯作者：
P. Schiavone
中科院分区：
文献类型：
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作者：
S. Soulan;M. Besacier;T. Lévéder;P. Schiavone
微电子制造业的在线过程控制需要实时和非侵入式监控技术。在不同的测量技术中，散射测量法是基于对图案结构散射光的椭偏特征（即斯托克斯系数与波长）的分析，似乎是很适合的。传统上用模态方法处理形状的定义和特征的计算问题，称为直接问题。相反，逆问题可以通过实验信号采集找到光栅形状，但不容易解决。已经引入了不同类型的算法（进化算法、单纯形算法等）来解决这个问题，但是库搜索方法似乎是对工业界最有吸引力的技术。本文将介绍该技术的许多优点，但其在实时环境中的主要限制在于不同波长的数据采集时间短。事实上，数据的缺乏导致了方法的失败，并且有几种数据库模式可以与实验数据匹配。本文提出了一种利用动态散射法实时重建光栅形状变化的方法。然后介绍了实现这种重构的不同工具，如傅里叶展开模态法、正则化技术和具体的软硬件体系结构。最后给出的动态实验结果将对本文进行说明。
In-line process control in microelectronics manufacturing requires real-time and non-invasive monitoring techniques. Among the different metrology techniques, scatterometry, based on the analysis of ellipsometric signatures (i.e stokes coefficients vs. wavelength) of the light scattered by a patterned structures, seems to be well adapted. Traditionally, the problem of defining the shape and computing the signature is dealt with modal methods and is called direct problem. On the opposite, the inverse problem allows to find the grating shape thanks to an experimental signature acquisition, and can not be solved as easily. Different classes of algorithms have been introduced (evolutionary, simplex, etc.) to address this problem, but the method of library searching seems to be the most attractive technique for industry. This technique has many advantages that will be presented in this article, however the main limitation in real-time context comes from the short data acquisition time for different wavelengths. Indeed, the lack of data leads to the method failure and several database patterns can match the experimental data. In this article, a technique for real time reconstruction of grating shape variation using dynamic scatterometry is presented. The different tools to realize this reconstruction, such as Modal Method by Fourier Expansion, regularization technique and specific software and hardware architectures are then introduced. Results issued from dynamic experiments will finally illustrate this paper.