Electron beam inspection apparatus stage positioning

An electron beam apparatus includes an electron optics system to generate an electron beam, an object table to hold the specimen at a target position so that a target portion of the specimen is irradiated by the electron beam, and a positioning device to displace the object table relative to the electron beam. The positioning device includes a stage actuator and a balance mass. The stage actuator exerts a force onto the object table to cause an acceleration of the object table. The force onto the object table results in a reaction force onto the balance mass. The balance mass moves in response to the reaction force. The positioning device enables the balance mass to move in a first direction in response to a component of the reaction force in the first direction.