Analytical Model of the 'Shot Noise' Effect in Photoresist

Decreasing feature size implies increased sensitivity to statistical fluctuations in various process parameters wuch as dose and the number of relevant bonds broken during post exposure bake. Here we develop a generic analytical model which accounts for essentially all these effects. The lowest order contribution to surface roughness from the bond statistics alone are shown to be very similar to recent experimental data. The lowest order contribution to a scaling law for predicting edge roughness is also derived.