走査型電子顕微鏡における磁場シールド制振による像ノイズの低減

概要

論文の詳細を見る
This paper addresses Scanning Electron Microscope (SEM). Not only the mechanical vibration but also electro-magnetic field influences the quality of SEM image. The vibration of the electron beam path also causes SEM image noise. We investigated the eigen mode shapes of the magnetic shield experimentally, and found out the frequency of the image noise measured with "Spot-beam analysis" corresponded to those natural frequencies. With changing the acceleration voltage of the electron beam, it was shown that the vibration of the magnetic shield affected magnetically to the electron beam path. As countermeasures, the damping structures with and without binding part were applied. Both structures were effective, however the structure with binding part changed the eigen modes of the magnetic shield and the frequency properties of SEM image noise. Thus, the damping structure without binding part would be more desirable to reduce the magnetic shield vibration. The damping structure had been applied to SEM, and remarkable reductions of the image noise from 250 to 500Hz band in 1/3 octave band were shown. This effect would be more remarkable when the acceleration voltage of the electron beam was smaller to reduce the electron damage to the specimen.
公益社団法人精密工学会の論文
2008-11-05