Comparison of ultimate resolution achieved by e-beam writers with shaped beam and with Gaussian beam

This contribution deals with the comparison of two different e–beam writer systems. E–beam writer with rectangular shaped beam BS600 is the first system. This system works with electron energy of 15 keV. Vistec EBPG5000+ HR is the second system. That system uses the Gaussian beam for pattern generation and it can work with two different electrons energies of values 50 keV and 100 keV. The ultimate resolution of both systems is the main aspect of comparison. The achievable resolution was tested on patterns consisted of single lines, single dots (rectangles for e–beam writer with shaped beam) and small areas of periodic gratings. Silicon wafer was used as a substrate for resist deposition. Testing was carried out with two resists, PMMA as a standard resist for electron beam lithography, and HSQ resist as a material for ultimate resolution achievement. Process of pattern generation (exposition) is affected by the same undesirable effect (backscattering and forward scattering of electrons, proximity effect etc.). However, these effects contribute to final pattern (resolution) by various dispositions. These variations caused the different results for similar conditions (the same resist, dose, chemical developer etc.). Created patterns were measured and evaluated by using of atomic force microscope and scanning electron microscope