一种光谱型椭偏仪的校准方法

A calibration method for spectroscopic ellipsometer

针对光谱型椭偏仪校准结果受测量模型影响大的问题进行研究,提出一种不受测量模型影响的校准方法,即通过校准椭偏角实现光谱型椭偏仪的校准。依据椭偏仪测量原理,通过仿真分析确定实现较大范围内椭偏角校准所需标准样片的薄膜厚度量值,并采用半导体热氧化工艺制备出性能稳定的膜厚标准样片。使用标准样片对型号为M-2000XF的光谱型椭偏仪的椭偏角进行校准,样片厚度为2,50,500 nm对应的椭偏角偏差分别在±0.6°,±1.5°,±2°以内,该偏差对薄膜厚度的影响不超过±0.5 nm。经实验表明:该方法不受椭偏仪测量模型的影响,可有效解决光谱型椭偏仪的校准问题。

In order to solve the problem that spectroscopic ellipsometry calibration results is effected by measurement model, a calibration method without being influenced by measurement model is proposed to calibrate spectroscopic ellipsometer by calibrating the elliptic angle. Standard sample film thickness required by calibration of elliptic angle is determined in wide range via simulation analysis based on the ellipsometry principle, and film thickness standard sample with stable performance is fabricated by using semiconductor thermal oxidation process. When calibrating the elliptic angle of M -2000XF spectral ellipsometer by standard samples, the deviations of elliptic angle corresponding to the thickness of 2,50,500 nm are within ±0.6., ±1.5.,±2., and result in the influence on the thickness of film no more than ±0.5nm. The test shows that this method is not affected by the ellipsometry measurement model, and it can effectively solve the calibration problem of spectroscopic ellipsometer.