不連續製鍍法降低高反射鏡之薄膜應力

Residual stress of high reflection mirror with a discontinued sputtering process

呂聿堂(Ywh-Tarng Leu)

指導教授 ： 李正中 ； 陳昇暉

國立中央大學/理學院/光電科學研究所/碩士(2011年)

摘要

本論文以不連續製鍍法來製鍍高低折射率材料 Ta2O5 與SiO2 的光學薄膜以達到「在不影響光學常數與薄膜品質的條件下，減低薄膜的殘留應力」的目標。 本實驗在光學性質的測量部分，是利用光譜儀量測，看不同參數的不連續製鍍法會不會對光譜產生飄移，來決定光學常數是否產生改變；在薄膜應力的量測部分，利用Twyman – Green 干涉儀測量其鍍膜前後樣品的撓曲量變化，再代入Stoney 公式得到薄膜應力大小；掃描式電子顯微鏡來觀看薄膜橫切面的介面；原子力顯微鏡用來量測薄膜的表面粗糙度，以驗證在此實驗中粗糙度跟應力變化的關係。 實驗結果部分，我們發現用使用不連續製鍍法中，應力並不隨切層數的增加而有增加或減少，反而會呈現增減交錯的變化結果。因為本實驗主要原理是利用增加介面應力來降低薄膜的殘留應力，所以當增加的介面應力無法與切薄厚度的薄膜應力抗衡時，總殘留應力就會增加；相反的，如果介面應力可以抵消每一層薄膜應力，那麼總殘留應力將會減小。 應用不連續製鍍法的到高反射鏡的結果，可以發現，在光學常數上的影響極小，而在降低應力的結果方面，可以達到17.6%的降低效果。

關鍵字

高反射鏡 ； 不連續製鍍法 ； 應力

並列摘要

In this study, the discontinuous sputtering process has been applied to fabricate the optical thin films of Ta2O5 and SiO2. The residual stresses of the films can be decreased without affecting the optical parameters of the films.
The measured spectra could confirm whether the optical parameters of the thin films have been changed or not. Besides, the residual stresses of the films have been measured by Twyman-Green interferometer. We utilized the amount of deflection of the substrate before and after thin-film depositing to calculate the stress by Stoney’s equation. Furthermore, the interfaces and roughness of the
films were measured by Scanning Electron Microscopy (SEM) and Atomic Force Microscope (AFM).
The experiment results of high reflection mirror showed the optical constants were almost the same, because the full width half maximum of high reflection mirror spectrum was almost the same, and the residual stress of the high reflection mirror fabricated by the cutting method (H, 1/3L*3) was -0.423GPa and that fabricated by the traditional method was -0.507GPa. The reduction ratio of the residual stress was 17.6%.

並列關鍵字

high reflection mirror ； stress ； discontinued sputtering process

參考文獻

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