System specifications

The tables below list the accelerating voltages available in the four operating modes, together with the maximum field sizes and minimum scanning steps. Fields can be stitched together to write a whole wafer using a translation stage. The stage moves in a step-and-repeat mode guided by an optical interferometer. The specified stitching accuarcy is better than 40nm, although the system outperforms this (see section on performance below). The specified minimum linewidth is < 10nm, with 9.8nm being achieved.

e-beam writing times

e-beam mode Accelerating voltage Objective lens Maximum field size
1 25 kV Fourth lens 2mm x 2mm
2 50 kV Fourth lens 1mm x 1mm
3 25 kV Fifth lens 200 μm x 200 μm
4 50 kV Fifth lens 100 μm x 100 μm

Scanning step size

e-beam mode Minimum scanning step
1 10 nm
2 5 nm
3 1 nm
4 0.5 nm

The image below shows one of the sample holders capable of holding samples 1cm across of various lengths.

Writing times depend on beam current and the resist used. A range of typical values is given in the table below. Patterns can be written directly on the system, or imported as DXF files.

Writing times

Beam current Beam diameter Exposure time (PMMA)
0.1 nA ~5 nm ~1 day/mm2
1 nA ~10 nm ~1 h/mm2
10 nA ~25 nm ~10 min/mm2

Typical doses for various resists

Resist, Dose in &mu
ma-n 1400