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An advanced microcolumn is proposed which adopts a modified einzel lens structure. The newly designed einzel lens is composed of four electrodes. The two center electrodes are specially designed electrostatic quadrupole (EQ) einzel lenses having keyhole instead of circular apertures. We constructed the advanced microcolumn with the EQ-einzel lenses, and operated the newly designed microcolumn in single lens mode and double-lens mode. The preliminary results show that the EQ-einzel lens can improve the performance of the micro-column for large sample applications.

Electron optical image correction subsystem in electron beam projection lithographyA novel magnetic microstigmator was developed for the astigmatism correction in the electron beam microcolumn system. The magnetic microstigmator consists of eight magnetic poles coupled with micromachined solenoid-type coils that are divided into four pairs. The proposed magnetic microstigmator was fabricated using microelectromechamical system technology and was assembled in an electron beam microcolumn for testing. The preliminary experimental results show that the developed magnetic microstigmator can effectively correct the astigmatism of the electron beam in the electron beam microcolumn with a driving current of 300 mA and low power. Rong et al.: Novel magnetic microstigmator for electron beam microcolumn system 2022