在科技蓬勃發展的年代，各式分析儀器均逐漸朝向微型化、低成本、便利地趨勢發展。桌上型的電子顯微鏡也在近年來走向商業化。現有桌上型掃描式電子顯微鏡利用永磁作為聚焦透鏡來達到系統微型化的目的，但微型化的同時卻也犧牲可調整的特性，在不同加速電壓與工程上都會導致無可避免的缺陷。另一方面傳統立地式電鏡利用電磁線圈作為聚焦透鏡在不同加速電壓下調整強度來維持電子光學系統的特性不變，然而在產生相同聚焦能力條件下，傳統電磁線圈所需要的體積遠大於永久磁鐵。在本論文中，我們提出一個新型電磁聚焦透鏡模組，使此一透鏡模組在體積上比現有永磁透鏡體積小的同時，在1kV-15kV加速電壓下維持全系統光學性質可以做調整。

另一方面，為了有效校準電子束準直性，我們也發展了偏轉器來精準校正電子束的的軌跡來達到更好的解析度及輝度，有別於以往在空間限制下，只能利用機械式調光系統來校準電子束準直性的缺點。

最後，我們也成功利用開發出的新型透鏡拍攝出掃描式電鏡的影像。在本論文中，我們將提出理論及設計基礎來實現所需要滿足的透鏡條件。從模擬結果可以知道，藉由適當的透鏡及偏轉器設計，可調式透鏡能補償傳統電磁透鏡磁通量密度不足，以及永久磁鐵缺乏的可調整的缺點，此一模組可以產生比原來更小的縮小倍率並維持電子束斑在0.5奈米以下。

With the advance of science and technology, all kinds of analytical instruments are gradually developed into miniaturization, low cost and convenience. The tabletop Electron Microscopes (tabletop EMs) have been commercialized in the recent years. A tabletop scanning electron microscope (SEM) utilizes permanent magnets as condenser lenses to minimize its size, but this sacrifices the tunability of condenser lenses such that a tabletop system can only be operated with a fixed accelerating voltage and it would be difficult to adjust if the permanent magnets decline after a long time operating. In contrast, the traditional condenser lens utilizes an electromagnetic coil to adjust the optical properties, but the size of the electromagnetic lens is inevitably larer. Here, we propose a tunable condenser lens for a tabletop SEM that uses a new design of electromagnetic coils. The overall dimensions of the newly designed lens are less than the original permanent magnet lens, but the new lens allows the tabletop SEM to be operated at different accelerating voltages between 1 kV and 15 kV.

On the other hand, in order to increase the alignment precision of the beam, here we integrate a pair of deflector with the tunable condenser lens to align electron beam. Also maintaining the compact column volume. An deflector is added in our desktop system between the anode and the condenser lens allows for more electron beam pass through the lens system to improve the signal/ noise ratio at the image plane.

Finally we success using the new type electromagnetic lens taking an image in tabletop scanning electron microscope. In this paper, we will propose theory and the basic of design to achieve the lens condition. According to the result of simulation, by the suitable design of lens and deflector, tunable lens can compensate the insufficient magnetic flux density of the traditional electromagnetic lens and the untunable defect. And also align the beam more precision than the general tabletop EM. This module can produce a smaller reduction ratio than the original and maintain the electron beam spot below 0.5 nm

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