基於像散式光學輪廓儀之定量反射率量測方法

A Method of Quantitative Reflectivity Measurement based on an Astigmatic Optical Profilometer

劉晏昀(Yan-Yun Liou)

指導教授 ： 廖先順

國立臺灣大學/工學院/機械工程學研究所/碩士(2021年)

https://doi.org/10.6342/NTU202104000

摘要

光學輪廓儀為非接觸式之量測儀器，可量測樣品表面之形貌、粗糙度等資訊，已被廣泛應用於晶圓製造、電子電機及生醫工程等領域。像散式光學輪廓儀係利用商用光學讀取頭作為其感測元件，具有低成本、高解析度及體積小等優點。此外，在Z軸調變模式下，像散式光學輪廓儀可量測XY平面上各位置之S曲線，進而在具不同反射率材料之表面上得到量化之高度影像。其中，量測所得到之S曲線線性區間之斜率與表面反射率呈現正相關。然而，現有之像散式光學輪廓儀仍無法得到量化之表面反射率。本論文利用一自製像散式光學輪廓儀對已知反射率之樣品進行S曲線量測，據此建立S曲線之斜率及峰對峰值等特徵與反射率之間的線性關係式。為驗證前述所得之反射率定量線性關係，實驗利用Z軸調變模式量測一鍍有鉻之玻璃基板樣品R2L2S1N1，得到之量化反射率結果與商用儀器所量測之樣品實際反射率進行比較，發現斜率之關係式可得到誤差較小之結果，在鉻與玻璃上之誤差分別為6.30%及2.30%。

關鍵字

光學輪廓儀 ； 反射率量測 ； 像散光學原理

並列摘要

Optical profilometer (OP) is a non-contact instrument for measuring the surface morphology and roughness, which has been widely used in multiple fields such as semiconductor manufacturing, electrical engineering and biomedical engineering. In this study, we focus on the astigmatic optical profilometer (AOP) with a commercial optical pick-up head as the sensing element, which has advantages including low cost, high resolution, and compact size. Through the Z-axis modulation mode, AOP is able to obtain the quantitative height image of the sample surface. Moreover, the slope of the linear region in the S-Curve has positive correlation with the surface reflectivity of the sample. However, the quantitative reflectivity is still not available in the current AOP. Herein, the relation between the S-Curve features and surface reflectivity was calibrated by measuring the standard samples. The results showed that both the peak-to-peak value and the slope of the S-Curve were approximately proportional to the reflectivity. To verify the calibrated relation, a standard sample R2L2S1N1 with a chrome coating on a glass substrate was measured using the Z-modulation mode. Then the results of quantitative reflectivity by the relation are compared with the actual reflectivity by the commercial instrument, we find the relation based on the slope of the S-Curve has less error of reflectivities on the surfaces of the glass substrate and the chrome coating, to be 6.30% and 2.30% respectively.

並列關鍵字

optical profilometer ； reflectivity measurement ； optical astigmatism

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