AN ELECTRON-BEAM LITHOGRAPHY TOOL WITH A SCHOTTKY EMITTER FOR WIDE-RANGE APPLICATIONS

An electron beam lithography tool with a Schottky field emitter source has been designed. The electron beam column can produce beam diameters between 6 nm and 250 nm, with corresponding currents up to 250 nA at 20, 50 and 100 kV accelerating voltage. It has been demonstrated that the tool is suitable for both very high resolution and fast reticle production. Feature sizes below 15 nm were resolved in resist after exposing with a calculated spot of 5.6 nm at 50 kV. Masks were produced with a 250 nm / 250 nA beam at 50 kV. The overlay between three masks was measured to be 78 nm over a 100 mm area and the placement accuracy in each mask was better than 60 nm. The stability at 50 kV was below 30 nm/h in position and around 1 %/h in current. 100 kV measurements showed an open loop position stability of better than 20 nm/h and 3 %/h current variation.