- 學位論文
高解析度反射式三維光電顯微鏡之研究
High-precision Reflection-type Three-dimensional (3D) Electro-optics Microscope
摘要
本研究提出「高解析度反射式三維光電顯微鏡」以高倍率反射量測方式，結合CCD光強度影像分析技術來量測出CD溝槽之三維表面輪廓。由於CD溝槽間隔極小，必須要使用高倍率之物鏡來放大其影像以利觀察，若要再增加其放大倍率則可在CCD前再加入兩個透鏡，並且可濾除空間雜訊，使影像清晰可見。 當一經擴束後之平行光投射在待測物上後，表面上的高度落差會造成反射光角度的改變，再經由平行四邊形稜鏡形成靈敏的出射光強度變化。因此可以很清楚的看出待測物表面上高度的變化，這是因為在臨界角附近入射角度變化與平行四邊形稜鏡之反射率變化成正比的關係，而且投射在平行四邊形稜鏡的入射角度變化又與待測表面高度成正比的關係。因此反射率變化量與高度差成正比，所以最後就可以利用CCD所擷取到的光強度變化來分析待測表面的三維形貌。 此「高解析度反射式三維光電顯微鏡」利用高倍率物鏡來放大CD溝槽之影像，可以立即得到二維表面輪廓，但若從CCD即時的影像分析其反射率，即可轉成三維表面形貌，從中可以馬上得到我們想要的任何一維的資訊，此量測方式不但可以做快速之量測，而且在組裝方面也很容易，精確度也相對提高。本研究結果顯示，對於光學放大倍率為1250倍、NA=0.7的顯微鏡而言，其橫向與縱向解析度分別為0.55μm與0.7nm，量測深度最大為183nm，精確度為±2%。
並列摘要
In this study, we proposed a new microscopy named as “High-precision reflection-type three-dimensional (3D) electro-optics microscope” for CD groove measurements. The method is based on geometrical optics and the critical angle method with a high magnification objective and two CCD cameras. For submicron lateral resolution measurement, we add two lenses to increase its magnification. The deflection angle of the reflection light from the test CD is proportional to its surface height. In addition, the reflectance of a parallelogram is also proportional to the incident angle near at the critical angle. Thus the output light intensity is proportion to the surface height. We utilize two CCDs to capture the image profiles. One profile is captured at TIR as a reference profile and another is captured near at the critical angle. The ratio of them is a reflectance profile that is used to calculate the final results of the surface height. Therefore, the surface height of each point on CD is obtained. This method is a non-scanning and non-interferometric method. From the high magnification microscope, the two dimensional image is directly captured by CCD. Furthermore, in our method, the reflectance of each point on the surface reveals the third dimensional information. Thus, the three-dimensional profile can be organized and displayed using the Matlab program. Not only CD but other submicron specimen could be tested. The microscope with submicron lateral and nanometer axial resolutions has other merits, such as, simple structure, easy operation, large area test at one shot, and 3D measurement, etc. It is applicable for MEMs measurement, surface analysis, and industrial application.