Charge Neutralization Using Focused 500 eV Electron Beam in Focused Ion Beam System

We have proposed a technique for novel charge neutralization in a focused ion beam (FIB) system. To neutralize positive charges induced by FIB, this technique utilizes a focused 500 eV electron beam instead of an electron shower that often causes negative charges in a broad area around the FIB-irradiated point. We used erasable-programmable read-only memory devices to monitor surface charges. The results showed that the focused electron beam is effective for charge neutralization and prevented threshold voltage shifts of both irradiated and neighboring transistors. We also found that the ratio of electron to ion beam currents is a key parameter to achieving effective charge neutralization.