INFLUENCE OF ELECTRON-IRRADIATION OF THE NOVER-1 VACUUM RESIST ON ITSRESISTANCE TO ION-BEAM ETCHING

The influence of electron irradiation on the resistance of the NOVER-1 resist to ion-beam etching is studied. Etching is carried out by argo n ions with energies between 300 and 2500 eV. It is found that, depend ing on the energy and angle of incidence of the ions on the surface of the resist, electron irradiation may either speed up or slow down the NOVER-1 etching. A clear correlation is observed between the penetrat ion depth of the ions in the resist and the influence of the electron irradiation on the resistance of the resist to etching. At ion energie s higher than 500 eV (ion penetration depth greater than or similar to 3.5 nm) the resistance decreases, passes through a minimum at low ele ctron irradiation doses, and returns to the etching rate of the initia l resist at high doses. For glancing etching angles (similar to 70 deg rees to the surface normal) and low ion energies (300 eV), i.e., small ion penetration depths (less than or similar to 2.5 nm), an electron- irradiated resist is etched more slowly than the initial resist at all the electron irradiation doses studied. This effect may be used to en hance the resistance of resist structures whose height exceeds their w idth, which in this case is determined mostly by the rate of etching o f the inclined facets. (C) 1998 American Institute of Physics, [S1063- 7842(98)03001-3].