Ion beam lithography: An investigation of resolution limits and sensitivities of ion-beam exposed PMMA

Abstract

High resolution thin-membrane masks are duplicated in PMMA by contact printing with 250 ke V Ga + ions, Upon development, minimum feature widths on the order of 70 nm are obtained, Broadening of ion-exposed lines in PMMA as a function of development time is studied, A microscopic investigation of PMMA irradiated with 50 ke V H + ions and 250 ke V Ga + ions at doses near the development threshold reveals peculiar morphological modifications prior to, and following development. The modification of theoretical energy dissipation distributions with the inclusion of recoil atoms in heavy-ion irradiation of resists is investigated with the aid of a Monte Carlo simulation program (RECUL). Using the three-dimensional energy distributions thus obtained, developed-line profiles are simulated,

Neutral particle lithography: a simple solution to charge-related artefacts in ion beam proximity printing

“…The intrinsic advantages of light ions over electrons are the significantly smaller beam spreading as it passes through resist and the absence of a proximity effect due to resist exposure by backscattered particles [26,27]. A TRIM [28] simulation of the spreading of a point source of He + and H + ions in PMMA resist is shown in figure 7 for incident energies of 10, 30 and 50 keV.…”

Integration of Scanning Probes and Ion Beams

“…Markers were imaged and an off marker area was selected with the SP. The equivalent argon ion dose per dot was approximately 10 13 cm -2 (or several μC).…”