Electron beam drift detection device and method for detecting electron beam drift

An electron beam drift detection device, comprising:

• a characteristic identification pattern placed on a surface of a workpiece and having a predetermined shape;
• an electron beam emission module used for emitting an electron beam, the electron beam emission including an electron beam focus and deflection coil module that focuses and deflects the electron beam such that the focused and deflected electron beam scans the surface of the workpiece and the characteristic identification pattern;
• a backscattered electron and secondary electron detection module detecting backscattered electrons and secondary electrons generated as a result of action of the focused and deflected electron beam upon the surface of the workpiece and the characteristic identification pattern, and thus providing corresponding detection signals;
• and
• an image processing module receiving the detection signals and performing an image process on the detection signals in order to obtain electronic image of the characteristic identification pattern, and measuring a drift degree of the electronic beam by comparing the electronic image and the predetermined shape of the characteristic identification pattern.