本研究提出了一種新的方法，將橢偏技術和光譜反射量測結合，用於分析光學薄膜的特性，包括厚度和折射率。為了確保測量的準確性，在進行實際薄膜量測之前，先透過模擬方式做誤差分析，以了解可能的誤差來源及其對結果的影響。此做法有助於在實驗過程中迅速識別出潛在的問題，並採取修正措施，從而提高整體的準確度。 完成模擬分析後，進一步對分析結果預測各種參數的誤差閾值。例如，在預期的誤差範圍內，如厚度誤差小於2奈米和折射率誤差小於0.5%的情況下，則在實際薄膜量測中，偏振角和檢偏角的絕對值誤差需小於0.1度，而入射角的絕對值誤差需小於0.2度。這些誤差閾值確保了在實驗過程中所獲得的結果能夠在可接受的範圍內保持一定的準確性。 為了實現最佳的擬合效果，本研究使用了基因演算法，以找到在整個參數空間中的全域最佳解。此外，採用了RAE架構和四點量測法，以實現快速的系統量測和計算。這些選擇不僅加速了測量過程，還使操作變得更加簡便。 在實際的穩定性測試和標準片測試中，成功地驗證了系統的穩定性和準確性。隨著誤差的減少和程式的優化，將超薄膜與JA Woo的擬合結果相比，發現此系統所量測的厚度絕對誤差皆小於0.8奈米，而折射率的百分誤差也皆小於1%，再次呈現了系統穩定性與精確度。 總結而言，本研究所提出的方法和系統為分析光學薄膜的特性提供了一個強大的工具。通過結合橢偏技術和光譜反射量測，並在模擬分析的指導下，成功地實現了對數奈米級厚度的高精度量測。;This study proposes a novel approach that combines ellipsometry techniques with spectral reflection measurements to analyze the characteristics of optical thin films, including thickness and refractive index. To ensure measurement accuracy, error analysis is conducted through simulations before actual thin film measurements are performed. This practice aids in promptly identifying potential issues during the experimental process and taking corrective measures to enhance overall accuracy. Following the simulation analysis, further prediction of error thresholds for various parameters is carried out. For instance, within the anticipated range of errors, such as thickness deviations below 2 nanometers and refractive index errors less than 0.5%, the absolute errors of polarizing angles and analyzer angles in actual thin film measurements need to be less than 0.1 degrees, while the absolute error of the incident angle should be less than 0.2 degrees. These error thresholds ensure that the results obtained during the experimental process maintain a certain level of accuracy within acceptable limits. To achieve optimal fitting effects, this study employs a genetic algorithm to identify the global best solution within the entire parameter space. Additionally, the use of the RAE architecture and a four-point measurement method facilitates rapid system measurement and computation. These choices not only expedite the measurement process but also simplify operations. Stability tests and standard sample assessments successfully validate the stability and accuracy of the system. With decreasing errors and program optimization, the measured thickness of ultra-thin films using this system exhibits absolute errors consistently below 0.8 nanometers, while the percentage error in refractive index remains below 1%, showcasing system stability and precision once again. In summary, the method and system presented in this study provide a potent tool for analyzing the characteristics of optical thin films. By combining ellipsometry techniques with spectral reflection measurements and guided by simulation analysis, the research effectively achieves high-precision measurements of sub-nanometer-level thickness.
