Chang Yia-Chung, Li Guangwei, Chu Hanyou, Opsal Jon
Department of Physics, University of Illinois at Urbana-Champaign, Illinois 61801, USA.
J Opt Soc Am A Opt Image Sci Vis. 2006 Mar;23(3):638-45. doi: 10.1364/josaa.23.000638.
We present an efficient method for calculating the reflectivity of three-dimensional gratings on multilayer films based on a finite-element, Green's function approach. Our method scales as NlogN, where N is the number of plane waves used in the expansion. Therefore, it is much more efficient than the commonly adopted rigorous-coupled-wave analysis (RCWA), which scales as N3. We demonstrate the effectiveness of this method by applying it to a two-dimensional periodic array of contact holes on a multilayer film. We find that our Green's function approach is about one order of magnitude faster than the RCWA approach when applied to typical contact holes considered in industry. For most cases, this method is efficient enough for application as a realtime, critical-dimension metrology tool.
我们提出了一种基于有限元格林函数方法来计算多层膜上三维光栅反射率的有效方法。我们的方法按NlogN缩放，其中N是展开中使用的平面波数量。因此，它比通常采用的严格耦合波分析（RCWA）效率高得多，后者按N3缩放。我们通过将该方法应用于多层膜上二维周期性接触孔阵列来证明其有效性。我们发现，当应用于工业中考虑的典型接触孔时，我们的格林函数方法比RCWA方法快约一个数量级。在大多数情况下，这种方法效率足够高，可作为实时临界尺寸计量工具应用。
