When the electron beam (EB) irradiates insulating films on a conducting substrate, the film charges positively or negatively, depending on the condition. The surface potential distribution is measured using an electrostatic force microscope installed in the specimen chamber of a scanning electron microscope. The multiple backscattering phenomenon of electrons between the specimen and the bottom of the objective lens electrode causes a global charging even a few millimeters away from the EB irradiation area. This charging can be suppressed by applying −5 V to the specimen. On the other hand, the charge in the irradiation area changes depending on the exposure dose. When the dose is small, it is positively charged, but when the exposure dose is large, it is negatively charged. However, as the dose increases, it becomes positive again. When the insulating film is irradiated with an EB, the charging potential disappears twice depending on the irradiation dose, and the electric potential distribution was found to be M-shaped and W-shaped. We propose a model to explain this phenomenon.

当电子束 (EB) 照射导电基板上的绝缘膜时，根据条件，该膜会带正电或带负电。使用安装在扫描电子显微镜样品室中的静电力显微镜测量表面电位分布。样品与物镜电极底部之间的电子多重背向散射现象会导致全局充电，即使距离 EB 照射区域几毫米。这种充电可以通过向样品施加 -5 V 来抑制。另一方面，照射区域的电荷根据照射剂量而变化。剂量小时带正电，照射剂量大时带负电。然而，随着剂量的增加，它再次变为阳性。当用 EB 照射绝缘膜时，根据照射剂量，充电电位消失两次，发现电位分布呈 M 形和 W 形。我们提出了一个模型来解释这种现象。