Method and apparatus for inspecting integrated circuit pattern using a plurality of charged particle beams

Abstract

In a pattern inspection device of the present invention having at least three electron-optical systems, detection signals approximately simultaneously obtained from identical circuit patterns are compared with each other. Further, areas around plural electron sources can be maintained at high degrees of vacuum by evacuating an electron gun chamber mounted with plural electron guns independently of a sample chamber. Further, electric fields and magnetic fields are confined in each electron-optical system by a shield electrode which makes it possible to evacuate an electron beam path to a high degree of vacuum, and at the same time, secondary electrons and reflected electrons are detected in the same electron-optical system by setting the samples to a negative voltage and accelerating secondary electrons and reflected electrons toward the electron source side in the direction of the electron beam axis. Thus, defect determination in pattern inspection is performable substantially simultaneously, and at the same time, the throughput of the inspections is improvable in proportion to the number of the electron-optical systems. Further, three or more electron sources are operable in a stable manner in high vacuum states, and signals from closely arranged electron-optical systems are detectable with high accuracy, and accurate inspections are performable.