The robustness of an algorithm applied in wafer-level material property extraction

In this paper, the robustness of a wafer-level testing algorithm was analyzed and the Taguchi methods were used to perform variability analysis on the effects of differences in test key structural length (∆L), material crystal direction, and structural length on the Young’s modulus (E) and mean stress (σ₀) of thin films. TSMC 0.18 μm process metal 2 was used as the test structure material for performing material parameter extraction. The results of this study indicate that structural length difference is the most crucial prominent factor and substantially affects the robustness of this algorithm. Besides, the Taguchi method analysis was then used to determine the suitable scope of application for this algorithm, and determine the optimal test key geometric parameter design that can be used for designing test keys.