本研究以史托克參數解出等效橢偏參數(Ѱp’p’, Ѱp’s’, Ѱs’p’, Δp’p’, Δp’s’, and Δs’p’)為理論基礎，不同於傳統式的橢偏參數僅能表示P-S波的關係，它可以表示任意方向的兩個正交波，在經過材料後其相互的振幅及相位關係，並以此基礎發展新式的偏振掃描式橢偏儀。此量測系統於量測過程中僅利用簡單的線性偏振光，即可解出所有方向的等效橢偏參數，並以這些參數作為基因演算法的目標函數，最後由基因演算法可以解出待測物的光學常數、物理參數。
一般的橢偏儀可以量測等向及非等向性光學薄膜的厚度與折射率，也可應用於TN，VA及ITN的向列型液晶量測，除了可以解出液晶的厚度，配向與預傾角，另外還可解出TN型液晶的扭轉角。然而，新型偏振掃描式橢偏儀藉由電光調變器調變相位產生各種不同角度的線性偏振光掃描待測材料; 同時，出射待測材料的偏振光再經由電子訊號調變的檢偏器量測並擷取，因此頻率響應較傳統式的橢偏儀高出許多。此外，藉由鋸齒波調變的檢偏器所擷取的訊號不需要利用鎖相放大器去抓出特定頻率與相位的訊號，也不需要複雜的解調變技術，僅利用簡單的傅立葉變換即可解出所有史托克參數，因此準確性較商用型動態史托克偏光儀高且其量測速度可藉由搭配200MS/s 資料擷取卡達到知名商用型 (Hinds Instruments) 動態史托克偏光儀的2000倍; 其量測過程中不需機械式旋轉任何光學元件及待測材料，不僅大幅降低機械擾動，並且可對待測材料做及時動態量測，進而了解材料參數隨時間的變化; 不論是薄膜的成長、液晶盒受外在電壓下傾角及扭轉角分佈的變化都可以藉由此動態量測系統量測出其光學參數的變化，因此可適用於液晶面板、光學薄膜、半導體製程上; 若搭配200MS/s 資料擷取卡, 每秒1000 組物理參數可經由新型動態偏振掃描式橢偏儀擷取出來。除此之外，自動光學檢測具有非破壞性和非接觸之優點，且可提供極佳的準確性。

A dynamic polarization scanning ellipsometry based on the Mueller matrix formulation and Stokes polarimetry is proposed for dynamically extracting the effective ellipsometric parameters of anisotropic material. The effective ellipsometric parameters (Ѱp’p’, Ѱp’s’, Ѱs’p’, Δp’p’, Δp’s’, and Δs’p’) describe the amplitude ratio and phase difference of two orthogonal waves in any arbitrary coordinate system with a scanning angle θ relative to the X-Y coordinate frame. The dynamic polarization scanning ellipsometry is composed of a linear polarization scanner and a polarization state analyzer. In a linear polarization scanner, an EO modulator is modulated to scan the linear polarization states of incident light with orientations in the range of 0˚ ~ 180˚. In a polarization state analyzer, two EO modulators are implemented for dynamically extracting the Stokes vectors. As a result, characteristic of a twisted nematic liquid crystal cell modulated by an AC voltage is verified by a dynamic polarization scanning ellipsometry. The dynamic variations in twist angle and tilt angle of a twisted nematic liquid crystal cell are successfully extracted by a genetic algorithm (GA) in curve fitting. Thus, without dynamically scanning the mechanical stage in the incident angle or the sample in a traditional ellipsometry or dynamically scanning spectrum in a spectroscopic ellipsometry, the frequency response in the new dynamic polarization scanning ellipsometry can be easily improved. Besides, this new system can also extract the Mueller matrix of the sample as long as the scattering effect of the sample is small enough to be ignored.
It is noted that 200000 groups of Stokes parameters per second can be extracted by using the new polarization state analyzer if 200MS/s DAQ card is used. As compared to the commercial PSA from a famous company (Hinds Instruments) with only extracting 100 groups of Stokes parameters per second, the performance of number groups of Stokes parameters per second is greatly improved. Importantly, the use of EO modulators will not only improve the angular resolution, but will also eliminate mechanical vibration from a rotation mechanical stage; thereby improving the accuracy of the measurement results.
In addition, this new dynamic polarization scanning ellipsometry can also provide high-speed measurement to characterize the physical properties of the anisotropic sample. For example, if 200MS/s DAQ card is used, 1000 groups of physical parameters per second can be extracted by using this new dynamic polarization scanning ellipsometry. Finally, the applications of the new dynamic polarization scanning ellipsometry in semiconductor/LCD industries can be explored in an in-line monitoring on thin-film growth on substrate and optical properties on LCD panel.

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