周期性光学薄膜应力建模

Stress modeling of periodic optical multilayer stack

  • 摘要: 光学薄膜应力会严重影响光学器件的表面面形,研究多层薄膜残余应力是高面形精度多层薄膜器件研制的核心。基于膜系结构和工艺过程重构周期性多层膜结构,建立了周期性多层膜残余应力模型,此模型与中心波长λ0、单周期应力σC、周期数m及周期间应力σC|C有关。设计了中心波长λ0=900 nm的周期性多层膜,使用应力模型估测残余应力,沉积该样片并通过基底形变法测试残余应力。测试结果表明,使用应力模型估测的残余应力与实测残余应力的误差约为30%,证明建立的周期性多层膜应力模型具有较高的精确度,适用于周期性多层膜应力估测。

     

    Abstract: The analysis of the residual in film is crucial to the fabrication of high accuracy multilayer device because it makes significant effects on the surface shape of the optical device. Based on film structure and deposition process, the periodic multilayer stack was reconstructed and then the residual stress model for periodic mutilayer stack was established. The model was related to the reference wavelength λ0, the residual stress in a single cycle σC, the numble of the cycles m, and the interfacial stress between the cycle σC|C. By designing and depositing a periodic multilayer with a reference wavelength λ0=900 nm, the residual stress of the sample was then calculated using the model and substrate deformation method. Comparison reveals that there is a about 30% error in the residual stress between estimating using the stress model and the measuring result. This demonstrates that the periodic multilayer stress model established in this study has high accuracy and qualifies for the stress estimation of periodic multilayer stack, further improving the accuracy of residual stress estimation of perodical multilayer stack.

     

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