Nanobeam process system: An ultrahigh vacuum electron beam lithography system with 3 nm probe size

Abstract

We have constructed a ‘‘nanobeam process system’’ which is applicable to high resolution electron beam lithography using inorganic resists and is also compatible with electron beam induced surface reaction. It is a 50 kV electron beam lithography system with a gas introducible ultrahigh vacuum sample chamber using a double chamber stage system which isolates stage mechanisms from the sample chamber. The probe size measured with a knife edge method was 2.8 nm, where the probe current was 127 pA. The base pressure of the sample chamber was 3.5×10−7 Pa after baking. The pressure of the gun chamber did not vary at all and the pressure rise of the mechanism chamber was 3×10−6 Pa when the pressure of the sample chamber increased to 1×10−3 Pa during N2 gas introduction. Standard deviations of stitching and overlay accuracy were 14 and 18 nm, respectively. Line patterns with a width of about 5 nm and a pitch of 15 nm were delineated in SiO2 when used as a high resolution resist.