【作者】 徐鹏；

【导师】 荣健；

【作者基本信息】 电子科技大学 ， 光学， 2013， 硕士

【摘要】 椭圆偏振测量仪是一种用于研究和测定薄膜以及材料光学性质的重要工具。其工作原理为：以一束偏振光入射到待测样品的表面，让其与待测样品之间发生相互作用(譬如反射、透射和散射等)，这些相互作用将会使其自身的偏振状态发生变化，通过检测该偏振光偏振状态的变化，便可确定或者计算出待测样品的厚度以及光学参数等信息。椭偏仪测量分辨率可以达到0.1的重复精度，而其准确性主要通过系统中的偏振器的物理信息校准保证；因此，系统校准方法决定了椭圆偏振的准确性。另一方面，随着时间和环境的变化，尤其在工业生产环境中，其系统的物理信息和校准参数会产生一定的变化，需要重复性的修正和校准才能够保证椭偏仪处于理想的状态。因此，快速、简单、准确的系统校准方法是维持椭圆偏振仪高效准确的关键环节。本文研究了一种基于标准测量参考系（标准样品）的椭圆偏振光谱仪系统参数校准方法，该方法简单、快速。该方法的基本思路是：如果被测样品的相关信息(折射率n,吸收系数k,厚度d)已知，则可以通过测量光强变化的傅里叶系数，采用最小二乘法原理反演出此时椭偏仪系统的信息（即校准参数:起偏器方位角P，检偏器方位角A，波片起始旋转角Cs，波片位相延迟δ,系统入射角θ0）。然后，再利用校准得到的系统参数和测量未知样品得到的光强傅里叶系数，进行数据的拟合分析，由此求得未知样品的参数值。本文以单波长椭偏仪为基础，对校准方法进行了模拟分析和验证。进行了2至6个标准样品参与校准的实验及该方法的可行性验证，解决和分析了基于该方法下多解的问题和对于待校准参数入射角θ0的灵敏性分析。并且，将该方法用于实际测量，考证校准后的测量效果，最大误差为2.6。在光谱椭偏仪方面，为了说明该方案的优点和实用性，本文对该种方案做了实验验证，将其用于薄膜检测；还结合RCWA算法，用于测量集成电路结构的三维形貌特征。通过本文的研究工作，发明了一种更适用于集成电路在线检测设备的快速修正的方法。并且此方法的灵敏性和准确性相比传统方法也更加优异。通过集成电路薄膜样品和CD样品的测量，验证了创新校准方法在集成电路工艺检测环节的有效性。更多还原

【Abstract】 Ellipsometric measurement instrument is an important tool for research andmeasurement of the optical properties of film and materials. Its principle is: a beam ofpolarized light is incident on the surface of the sample, and the beam will interact withthe sample, such as reflection, transmission, scattering; these interactions will lead tothe changes of polarization of beam depending on the sample’s own properties. Bymodeling the interaction between the polarized light and the sample, the thickness andthe optical parameters and other information of the sample can be determined from thecurve-fitting.The precision of ellipsometer can be achieved down to0.1, and its accuracyprimarily was guaranteed through the calibration of physical information of the system.Therefore, the system calibration method determines the accuracy of ellipsometer. Onthe other hand, especially in the industrial production environment, its physical andcalibration parameters will have variations with the time and environment change.Repetitive correction and calibration are required to keep the ellipsometer in a validstate for daily use. Therefore, a fast, simple, and accurate calibration method forellipsometry is critical for maintaining ellipsometer working efficiently and properly. Inthis thesis, a novel calibration method based on standard measurement reference system(standard samples) was revealed, and the method of calibration is simple and fast. Theprinciple is: if the relevant information of the samples (refractive index n, absorptioncoefficient k, thickness d) is given prior to the measurements (by more accuratemeasurement system or golden calibrated measurement system), the system calibratingparameters (angel of polarizer P, offset angle of compensator Cs,angel of analyzer A,phase shift of compensatorδ, and angel of incidenceθ0) can be deduced from thecomparison of the measured and calculated Fourier coefficients, with nonlinearregression and least square methods. These parameters will be used for systemcalibration and the system can be used to measure unknown samples.In this thesis, based on a single wavelength ellipsometer, the calibration method isanalyzed by simulation and verified by experiment. In detail, the calibration processrequires2to6standard samples, and the feasibility of the method is demonstrated and analyzed. The sensitivity of the angle of incidence and the numerical issue of multiplesolutions are analyzed systematically. Samples are measured by the calibrated systemand the maximum error is2.6. As to spectroscopic ellipsometry, the experimentalverification of the film measurement was carried on to illustrate the advantages of thenovel calibration method, including the combination of RCWA algorithm andmeasurement of the three-dimensional structure of the integrated circuit.In this thesis study, a novel calibration method is developed, which is fast, simpleand good for application in on-line integrated circuit metrology equipment compared tothe conventional method, and is more sensitive and accurate. Through the measurementof the integrated circuits film samples and CD samples, the validity of the innovativecalibration method in metrology of integrated circuit technology is demonstrated.更多还原