Shot-noise and edge roughness effects in resists patterned at 10 nm exposure

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. (C) 1998 American Vacuum Society. [S0734-211X(98)08606-5].