Line edge roughness investigation on chemically amplified resist materials with masked helium ion beam lithography

We conducted line edge roughness (LER) measurements on resists with various sensitivities, exposed with a 75 keV 1:1 masked ion beam lithography tool. The critical dimension measurement data were treated with an algorithm for separation of mask induced roughness from random LER. The scaling analysis approach provided the correlation length and the roughness exponent. The results indicate that for exposure doses >2.5 μC/cm 2 LER is not governed by shot noise but by the resist material properties (sensitivity, molecular weight, acid diffusion length) and development conditions.