Direct-write electron beam lithography in silicon dioxide at low energy

Abstract : Electron beam lithography in silicon dioxide has been investigated with energies ranging from 0.5 up to 6 keV. The etch ratio of SiO2SiO2 has been studied and interpreted with regard to the limited penetration of electrons at such low energies. Monte Carlo simulations have been carried out to investigate the depth of penetration and the density of energy absorbed by SiO2SiO2. The etch ratio is also shown to depend on the dilution of the developer (a buffered hydrofluoric acid diluted in water). Finally, a possible application of low energy direct writing in silicon dioxide is described for the control of damascene processes, enabling the fabrication of nanodevices embedded in an insulator.