Virtual Material Modeling and Vibration Reduction Design of Electron Beam Imaging System

The electron beam imaging system is used for wafer inspection, and its imaging accuracy is directly affected by the vibration characteristics of the system. In order to explore the influence of the vibration characteristics of the electron beam imaging system on its imaging accuracy, the key vibration transmission path was selected, and the high-precision joint surface virtual material modeling method was introduced into the structure to establish the whole vibration transmission model. The first 10 natural frequencies, mode shapes and the harmonious response of the electron gun tip are obtained by the finite element method. Two schemes of lens tube materials were proposed to increase the natural frequency, and the second solution suppressed the maximum response displacement of the gun tip to 83% of the original structure. Then the structure of the chamber was redesigned to reduce the displacement response of the electron gun tip when the molecular pump was working. The weight of the chamber of the final scheme is 75.6% of the original structure, and the response displacement of the electron gun tip are suppressed to about 40% the original structure, therefore improving the imaging accuracy.