Electrolithography

Electronolithography, or electron-beam lithography, allows patterns to be written directly onto the resist layer, resulting in possible feature dimensions at the level of single nanometers. It gives much greater flexibility in transferring patterns onto the layer compared to other types of lithography. This approach eliminates the need to produce and expose the patterns through a mask, as used, in photolithography. Thanks to this advantage, quick changes and corrections to the design of the patterns are possible. These advantages give electron-beam lithography a great deal of flexibility useful especially in the research and prototyping phase of structures and components. The accelerating voltages used is 100 kV. The minimum diameter of the electron beam used for exposure is less than 5 nm and the minimum width of the resulting line is less than 20 nm. The maximum exposure area without stitching is 1 mm2.

Technological possibilities:

• accelerating voltage 100 kV, exposure beam current range 0.1 – 50 nA. Exposure field sizes 100×100 μm, 500×500 μm and 1000×1000 μm
• stitching error of the exposure fields ≤±30 nm
• possibility to work with circular substrates with diameters of 2, 3, 4, 6, 8 inches and square substrates with side lengths of 5 and 7 inches
• Possibility to process nonstandard substrates by prior agreement, Possibility to work with positive (e.g. 950PMMA A from MicroChem and ZEP520A from Zeon) and negative (e.g. XR-1541 from Dow Corning) e-beam resists, others possible by prior agreement,
• resists layer thicknesses from several tens of nanometers upwards are possible
• minimum line width possible in negative resist from several nm, in positive resist from several tens of nanometers
• accepted patterns in files: LEDB, GDS OASIS, LTxt, CIF, DXF, PNG
• possibility of preparation and optimization of the exposure process – available software enables, among others, optimal selection and sequence of exposing areas to minimize mapping errors and shorten working time, preparation of beam dosage plan with consideration of proximity effects and visualization of exposure effects

Keywords: electronolithography, lithography, electron beam, exposure process

contact: uslugi.cezamat@pw.edu.pl