Nano-Electron-Beam lithography system and its application for 40-nm gate MOSFETs

A nanometer Electron Beam (EB) lithography system has been developed and used for fabricating nanometer order MOSFETs. The system uses a Zr/O/W Thermal Field Emitter (TFE) and has a 5nm-diameter beam at a current of 100 pA, an acceleration voltage of 50kV. A 10 nm line was successfully delineated in PMMA (Polymethyl Methacrylate) on a thick Si substrate. A chemically amplified negative resist was used as a single layer mask for minute MOSFET gate fabrication, and showed high resolution less than 0.1 μm width. Proximity effect correction was applied to the gate lithography, resulting in excellent line width control even less than 0.1 μm. Operation of a 40 nm-polysilicon gate nMOSFET was confirmed.