The experimental shot-noise effects and line-edge roughness are reported for two positive and two negative tone chemically amplified resists (IBM Apex-E, Shipley UVIIHS, IBM ENR, and Shipley SAL-601, respectively) produced by high resolution (10 nm) focused ion-beam exposure. Scanning electron micrographs at the resolution limit for each resist (50–70 nm) showed that the positive resists became negative in tone and that edge roughness was reasonable. Shot-noise effects causing arrays of 10 nm posts to print or not to print at exposure events of 7, 14, and 28 average ions per post were observed in SAL-601 and agree with Poisson statistics. Single exposure events were not observed in any resist possibly owing to the fact that the working minimum exposure level at the resolution limit of the resist material required several overlapping events to print.

Chemically-amplified resists show promise as patterning materials in many advanced lithography systems including optical, electron-beam and ion-beam systems. In this study, four such resists including IBM APEX-E, IBM ENR, Shipley UVIIHS, and Shipley SAL-601 (ion-beam and electron-beam exposure only) were characterized for the three methods of exposure to determine relative sensitivities, fundamental resolution limits, and diffusivity for each of the above mentioned exposure methods. It was discovered that volumetric exposure doses for ion-beam and electron-beam were roughly equivalent but all resists were more sensitive to optical exposure. This is most likely due to a difference in transfer of energy to the photoacid generator during the exposure. Resolution tests were conducted in ion-beam exposure with simple line/space array patterns. All resists demonstrated patterning capability with resolution limits of 150 nm, 70 nm, 70 nm, and 50 nm for APEX-E, SAL-601, UVIIHS, and ENR respectively. Evidence of a competing cross-linking mechanism in the positive tone resists was discovered from the resolution tests. From a simple electron-beam `post/hole' experiment with varying post-exposure bake times, it was determined that SAL-601 and APEX-E demonstrated the highest level of diffusivity while UVIIHS and ENR exhibited negligible levels of diffusion. The characterization tests demonstrated the suitability of all four resists as good ion-beam patterning materials in addition to their suitability for electron-beam and optical exposure.